Fri, 11 Jan 2019 13:34:57 +0100
8216559: [JFR] Native libraries not correctly parsed from /proc/self/maps
Summary: Use %7s for the dev scan format as major:minor may be up to that length
Reviewed-by: mgronlun, jwilhelm
1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 // no precompiled headers
26 #include "classfile/classLoader.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "classfile/vmSymbols.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/vtableStubs.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "compiler/disassembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "jvm_linux.h"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/filemap.hpp"
37 #include "mutex_linux.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "os_share_linux.hpp"
40 #include "osContainer_linux.hpp"
41 #include "prims/jniFastGetField.hpp"
42 #include "prims/jvm.h"
43 #include "prims/jvm_misc.hpp"
44 #include "runtime/arguments.hpp"
45 #include "runtime/extendedPC.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.hpp"
48 #include "runtime/init.hpp"
49 #include "runtime/java.hpp"
50 #include "runtime/javaCalls.hpp"
51 #include "runtime/mutexLocker.hpp"
52 #include "runtime/objectMonitor.hpp"
53 #include "runtime/orderAccess.inline.hpp"
54 #include "runtime/osThread.hpp"
55 #include "runtime/perfMemory.hpp"
56 #include "runtime/sharedRuntime.hpp"
57 #include "runtime/statSampler.hpp"
58 #include "runtime/stubRoutines.hpp"
59 #include "runtime/thread.inline.hpp"
60 #include "runtime/threadCritical.hpp"
61 #include "runtime/timer.hpp"
62 #include "services/attachListener.hpp"
63 #include "services/memTracker.hpp"
64 #include "services/runtimeService.hpp"
65 #include "utilities/decoder.hpp"
66 #include "utilities/defaultStream.hpp"
67 #include "utilities/events.hpp"
68 #include "utilities/elfFile.hpp"
69 #include "utilities/growableArray.hpp"
70 #include "utilities/vmError.hpp"
72 // put OS-includes here
73 # include <sys/types.h>
74 # include <sys/mman.h>
75 # include <sys/stat.h>
76 # include <sys/select.h>
77 # include <pthread.h>
78 # include <signal.h>
79 # include <errno.h>
80 # include <dlfcn.h>
81 # include <stdio.h>
82 # include <unistd.h>
83 # include <sys/resource.h>
84 # include <pthread.h>
85 # include <sys/stat.h>
86 # include <sys/time.h>
87 # include <sys/times.h>
88 # include <sys/utsname.h>
89 # include <sys/socket.h>
90 # include <sys/wait.h>
91 # include <pwd.h>
92 # include <poll.h>
93 # include <semaphore.h>
94 # include <fcntl.h>
95 # include <string.h>
96 # include <syscall.h>
97 # include <sys/sysinfo.h>
98 # include <gnu/libc-version.h>
99 # include <sys/ipc.h>
100 # include <sys/shm.h>
101 # include <link.h>
102 # include <stdint.h>
103 # include <inttypes.h>
104 # include <sys/ioctl.h>
106 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
108 #ifndef _GNU_SOURCE
109 #define _GNU_SOURCE
110 #include <sched.h>
111 #undef _GNU_SOURCE
112 #else
113 #include <sched.h>
114 #endif
116 // if RUSAGE_THREAD for getrusage() has not been defined, do it here. The code calling
117 // getrusage() is prepared to handle the associated failure.
118 #ifndef RUSAGE_THREAD
119 #define RUSAGE_THREAD (1) /* only the calling thread */
120 #endif
122 #define MAX_PATH (2 * K)
124 #define MAX_SECS 100000000
126 // for timer info max values which include all bits
127 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
129 #define LARGEPAGES_BIT (1 << 6)
130 ////////////////////////////////////////////////////////////////////////////////
131 // global variables
132 julong os::Linux::_physical_memory = 0;
134 address os::Linux::_initial_thread_stack_bottom = NULL;
135 uintptr_t os::Linux::_initial_thread_stack_size = 0;
137 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
138 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
139 int (*os::Linux::_pthread_setname_np)(pthread_t, const char*) = NULL;
140 Mutex* os::Linux::_createThread_lock = NULL;
141 pthread_t os::Linux::_main_thread;
142 int os::Linux::_page_size = -1;
143 const int os::Linux::_vm_default_page_size = (8 * K);
144 bool os::Linux::_is_floating_stack = false;
145 bool os::Linux::_is_NPTL = false;
146 bool os::Linux::_supports_fast_thread_cpu_time = false;
147 const char * os::Linux::_glibc_version = NULL;
148 const char * os::Linux::_libpthread_version = NULL;
149 pthread_condattr_t os::Linux::_condattr[1];
151 static jlong initial_time_count=0;
153 static int clock_tics_per_sec = 100;
155 // For diagnostics to print a message once. see run_periodic_checks
156 static sigset_t check_signal_done;
157 static bool check_signals = true;
159 static pid_t _initial_pid = 0;
161 /* Signal number used to suspend/resume a thread */
163 /* do not use any signal number less than SIGSEGV, see 4355769 */
164 static int SR_signum = SIGUSR2;
165 sigset_t SR_sigset;
167 /* Used to protect dlsym() calls */
168 static pthread_mutex_t dl_mutex;
170 // Declarations
171 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
173 // utility functions
175 static int SR_initialize();
177 julong os::available_memory() {
178 return Linux::available_memory();
179 }
181 julong os::Linux::available_memory() {
182 // values in struct sysinfo are "unsigned long"
183 struct sysinfo si;
184 julong avail_mem;
186 if (OSContainer::is_containerized()) {
187 jlong mem_limit, mem_usage;
188 if ((mem_limit = OSContainer::memory_limit_in_bytes()) < 1) {
189 if (PrintContainerInfo) {
190 tty->print_cr("container memory limit %s: " JLONG_FORMAT ", using host value",
191 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
192 }
193 }
195 if (mem_limit > 0 && (mem_usage = OSContainer::memory_usage_in_bytes()) < 1) {
196 if (PrintContainerInfo) {
197 tty->print_cr("container memory usage failed: " JLONG_FORMAT ", using host value", mem_usage);
198 }
199 }
201 if (mem_limit > 0 && mem_usage > 0 ) {
202 avail_mem = mem_limit > mem_usage ? (julong)mem_limit - (julong)mem_usage : 0;
203 if (PrintContainerInfo) {
204 tty->print_cr("available container memory: " JULONG_FORMAT, avail_mem);
205 }
206 return avail_mem;
207 }
208 }
210 sysinfo(&si);
211 avail_mem = (julong)si.freeram * si.mem_unit;
212 if (Verbose) {
213 tty->print_cr("available memory: " JULONG_FORMAT, avail_mem);
214 }
215 return avail_mem;
216 }
218 julong os::physical_memory() {
219 jlong phys_mem = 0;
220 if (OSContainer::is_containerized()) {
221 jlong mem_limit;
222 if ((mem_limit = OSContainer::memory_limit_in_bytes()) > 0) {
223 if (PrintContainerInfo) {
224 tty->print_cr("total container memory: " JLONG_FORMAT, mem_limit);
225 }
226 return mem_limit;
227 }
229 if (PrintContainerInfo) {
230 tty->print_cr("container memory limit %s: " JLONG_FORMAT ", using host value",
231 mem_limit == OSCONTAINER_ERROR ? "failed" : "unlimited", mem_limit);
232 }
233 }
235 phys_mem = Linux::physical_memory();
236 if (Verbose) {
237 tty->print_cr("total system memory: " JLONG_FORMAT, phys_mem);
238 }
239 return phys_mem;
240 }
242 ////////////////////////////////////////////////////////////////////////////////
243 // environment support
245 bool os::getenv(const char* name, char* buf, int len) {
246 const char* val = ::getenv(name);
247 if (val != NULL && strlen(val) < (size_t)len) {
248 strcpy(buf, val);
249 return true;
250 }
251 if (len > 0) buf[0] = 0; // return a null string
252 return false;
253 }
256 // Return true if user is running as root.
258 bool os::have_special_privileges() {
259 static bool init = false;
260 static bool privileges = false;
261 if (!init) {
262 privileges = (getuid() != geteuid()) || (getgid() != getegid());
263 init = true;
264 }
265 return privileges;
266 }
269 #ifndef SYS_gettid
270 // i386: 224, ia64: 1105, amd64: 186, sparc 143
271 #ifdef __ia64__
272 #define SYS_gettid 1105
273 #else
274 #ifdef __i386__
275 #define SYS_gettid 224
276 #else
277 #ifdef __amd64__
278 #define SYS_gettid 186
279 #else
280 #ifdef __sparc__
281 #define SYS_gettid 143
282 #else
283 #error define gettid for the arch
284 #endif
285 #endif
286 #endif
287 #endif
288 #endif
290 // Cpu architecture string
291 static char cpu_arch[] = HOTSPOT_LIB_ARCH;
293 // pid_t gettid()
294 //
295 // Returns the kernel thread id of the currently running thread. Kernel
296 // thread id is used to access /proc.
297 //
298 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
299 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
300 //
301 pid_t os::Linux::gettid() {
302 int rslt = syscall(SYS_gettid);
303 if (rslt == -1) {
304 // old kernel, no NPTL support
305 return getpid();
306 } else {
307 return (pid_t)rslt;
308 }
309 }
311 // Most versions of linux have a bug where the number of processors are
312 // determined by looking at the /proc file system. In a chroot environment,
313 // the system call returns 1. This causes the VM to act as if it is
314 // a single processor and elide locking (see is_MP() call).
315 static bool unsafe_chroot_detected = false;
316 static const char *unstable_chroot_error = "/proc file system not found.\n"
317 "Java may be unstable running multithreaded in a chroot "
318 "environment on Linux when /proc filesystem is not mounted.";
320 void os::Linux::initialize_system_info() {
321 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
322 if (processor_count() == 1) {
323 pid_t pid = os::Linux::gettid();
324 char fname[32];
325 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
326 FILE *fp = fopen(fname, "r");
327 if (fp == NULL) {
328 unsafe_chroot_detected = true;
329 } else {
330 fclose(fp);
331 }
332 }
333 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
334 assert(processor_count() > 0, "linux error");
335 }
337 void os::init_system_properties_values() {
338 // The next steps are taken in the product version:
339 //
340 // Obtain the JAVA_HOME value from the location of libjvm.so.
341 // This library should be located at:
342 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
343 //
344 // If "/jre/lib/" appears at the right place in the path, then we
345 // assume libjvm.so is installed in a JDK and we use this path.
346 //
347 // Otherwise exit with message: "Could not create the Java virtual machine."
348 //
349 // The following extra steps are taken in the debugging version:
350 //
351 // If "/jre/lib/" does NOT appear at the right place in the path
352 // instead of exit check for $JAVA_HOME environment variable.
353 //
354 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
355 // then we append a fake suffix "hotspot/libjvm.so" to this path so
356 // it looks like libjvm.so is installed there
357 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
358 //
359 // Otherwise exit.
360 //
361 // Important note: if the location of libjvm.so changes this
362 // code needs to be changed accordingly.
364 // See ld(1):
365 // The linker uses the following search paths to locate required
366 // shared libraries:
367 // 1: ...
368 // ...
369 // 7: The default directories, normally /lib and /usr/lib.
370 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
371 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
372 #else
373 #define DEFAULT_LIBPATH "/lib:/usr/lib"
374 #endif
376 // Base path of extensions installed on the system.
377 #define SYS_EXT_DIR "/usr/java/packages"
378 #define EXTENSIONS_DIR "/lib/ext"
379 #define ENDORSED_DIR "/lib/endorsed"
381 // Buffer that fits several sprintfs.
382 // Note that the space for the colon and the trailing null are provided
383 // by the nulls included by the sizeof operator.
384 const size_t bufsize =
385 MAX3((size_t)MAXPATHLEN, // For dll_dir & friends.
386 (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir
387 (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
388 char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
390 // sysclasspath, java_home, dll_dir
391 {
392 char *pslash;
393 os::jvm_path(buf, bufsize);
395 // Found the full path to libjvm.so.
396 // Now cut the path to <java_home>/jre if we can.
397 *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
398 pslash = strrchr(buf, '/');
399 if (pslash != NULL) {
400 *pslash = '\0'; // Get rid of /{client|server|hotspot}.
401 }
402 Arguments::set_dll_dir(buf);
404 if (pslash != NULL) {
405 pslash = strrchr(buf, '/');
406 if (pslash != NULL) {
407 *pslash = '\0'; // Get rid of /<arch>.
408 pslash = strrchr(buf, '/');
409 if (pslash != NULL) {
410 *pslash = '\0'; // Get rid of /lib.
411 }
412 }
413 }
414 Arguments::set_java_home(buf);
415 set_boot_path('/', ':');
416 }
418 // Where to look for native libraries.
419 //
420 // Note: Due to a legacy implementation, most of the library path
421 // is set in the launcher. This was to accomodate linking restrictions
422 // on legacy Linux implementations (which are no longer supported).
423 // Eventually, all the library path setting will be done here.
424 //
425 // However, to prevent the proliferation of improperly built native
426 // libraries, the new path component /usr/java/packages is added here.
427 // Eventually, all the library path setting will be done here.
428 {
429 // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
430 // should always exist (until the legacy problem cited above is
431 // addressed).
432 const char *v = ::getenv("LD_LIBRARY_PATH");
433 const char *v_colon = ":";
434 if (v == NULL) { v = ""; v_colon = ""; }
435 // That's +1 for the colon and +1 for the trailing '\0'.
436 char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
437 strlen(v) + 1 +
438 sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
439 mtInternal);
440 sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
441 Arguments::set_library_path(ld_library_path);
442 FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
443 }
445 // Extensions directories.
446 sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
447 Arguments::set_ext_dirs(buf);
449 // Endorsed standards default directory.
450 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
451 Arguments::set_endorsed_dirs(buf);
453 FREE_C_HEAP_ARRAY(char, buf, mtInternal);
455 #undef DEFAULT_LIBPATH
456 #undef SYS_EXT_DIR
457 #undef EXTENSIONS_DIR
458 #undef ENDORSED_DIR
459 }
461 ////////////////////////////////////////////////////////////////////////////////
462 // breakpoint support
464 void os::breakpoint() {
465 BREAKPOINT;
466 }
468 extern "C" void breakpoint() {
469 // use debugger to set breakpoint here
470 }
472 ////////////////////////////////////////////////////////////////////////////////
473 // signal support
475 debug_only(static bool signal_sets_initialized = false);
476 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
478 bool os::Linux::is_sig_ignored(int sig) {
479 struct sigaction oact;
480 sigaction(sig, (struct sigaction*)NULL, &oact);
481 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
482 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
483 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
484 return true;
485 else
486 return false;
487 }
489 void os::Linux::signal_sets_init() {
490 // Should also have an assertion stating we are still single-threaded.
491 assert(!signal_sets_initialized, "Already initialized");
492 // Fill in signals that are necessarily unblocked for all threads in
493 // the VM. Currently, we unblock the following signals:
494 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
495 // by -Xrs (=ReduceSignalUsage));
496 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
497 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
498 // the dispositions or masks wrt these signals.
499 // Programs embedding the VM that want to use the above signals for their
500 // own purposes must, at this time, use the "-Xrs" option to prevent
501 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
502 // (See bug 4345157, and other related bugs).
503 // In reality, though, unblocking these signals is really a nop, since
504 // these signals are not blocked by default.
505 sigemptyset(&unblocked_sigs);
506 sigemptyset(&allowdebug_blocked_sigs);
507 sigaddset(&unblocked_sigs, SIGILL);
508 sigaddset(&unblocked_sigs, SIGSEGV);
509 sigaddset(&unblocked_sigs, SIGBUS);
510 sigaddset(&unblocked_sigs, SIGFPE);
511 #if defined(PPC64)
512 sigaddset(&unblocked_sigs, SIGTRAP);
513 #endif
514 sigaddset(&unblocked_sigs, SR_signum);
516 if (!ReduceSignalUsage) {
517 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
518 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
519 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
520 }
521 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
522 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
523 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
524 }
525 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
526 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
527 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
528 }
529 }
530 // Fill in signals that are blocked by all but the VM thread.
531 sigemptyset(&vm_sigs);
532 if (!ReduceSignalUsage)
533 sigaddset(&vm_sigs, BREAK_SIGNAL);
534 debug_only(signal_sets_initialized = true);
536 }
538 // These are signals that are unblocked while a thread is running Java.
539 // (For some reason, they get blocked by default.)
540 sigset_t* os::Linux::unblocked_signals() {
541 assert(signal_sets_initialized, "Not initialized");
542 return &unblocked_sigs;
543 }
545 // These are the signals that are blocked while a (non-VM) thread is
546 // running Java. Only the VM thread handles these signals.
547 sigset_t* os::Linux::vm_signals() {
548 assert(signal_sets_initialized, "Not initialized");
549 return &vm_sigs;
550 }
552 // These are signals that are blocked during cond_wait to allow debugger in
553 sigset_t* os::Linux::allowdebug_blocked_signals() {
554 assert(signal_sets_initialized, "Not initialized");
555 return &allowdebug_blocked_sigs;
556 }
558 void os::Linux::hotspot_sigmask(Thread* thread) {
560 //Save caller's signal mask before setting VM signal mask
561 sigset_t caller_sigmask;
562 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
564 OSThread* osthread = thread->osthread();
565 osthread->set_caller_sigmask(caller_sigmask);
567 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
569 if (!ReduceSignalUsage) {
570 if (thread->is_VM_thread()) {
571 // Only the VM thread handles BREAK_SIGNAL ...
572 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
573 } else {
574 // ... all other threads block BREAK_SIGNAL
575 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
576 }
577 }
578 }
580 //////////////////////////////////////////////////////////////////////////////
581 // detecting pthread library
583 void os::Linux::libpthread_init() {
584 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
585 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
586 // generic name for earlier versions.
587 // Define macros here so we can build HotSpot on old systems.
588 # ifndef _CS_GNU_LIBC_VERSION
589 # define _CS_GNU_LIBC_VERSION 2
590 # endif
591 # ifndef _CS_GNU_LIBPTHREAD_VERSION
592 # define _CS_GNU_LIBPTHREAD_VERSION 3
593 # endif
595 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
596 if (n > 0) {
597 char *str = (char *)malloc(n, mtInternal);
598 confstr(_CS_GNU_LIBC_VERSION, str, n);
599 os::Linux::set_glibc_version(str);
600 } else {
601 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
602 static char _gnu_libc_version[32];
603 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
604 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
605 os::Linux::set_glibc_version(_gnu_libc_version);
606 }
608 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
609 if (n > 0) {
610 char *str = (char *)malloc(n, mtInternal);
611 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
612 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
613 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
614 // is the case. LinuxThreads has a hard limit on max number of threads.
615 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
616 // On the other hand, NPTL does not have such a limit, sysconf()
617 // will return -1 and errno is not changed. Check if it is really NPTL.
618 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
619 strstr(str, "NPTL") &&
620 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
621 free(str);
622 os::Linux::set_libpthread_version("linuxthreads");
623 } else {
624 os::Linux::set_libpthread_version(str);
625 }
626 } else {
627 // glibc before 2.3.2 only has LinuxThreads.
628 os::Linux::set_libpthread_version("linuxthreads");
629 }
631 if (strstr(libpthread_version(), "NPTL")) {
632 os::Linux::set_is_NPTL();
633 } else {
634 os::Linux::set_is_LinuxThreads();
635 }
637 // LinuxThreads have two flavors: floating-stack mode, which allows variable
638 // stack size; and fixed-stack mode. NPTL is always floating-stack.
639 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
640 os::Linux::set_is_floating_stack();
641 }
642 }
644 /////////////////////////////////////////////////////////////////////////////
645 // thread stack
647 // Force Linux kernel to expand current thread stack. If "bottom" is close
648 // to the stack guard, caller should block all signals.
649 //
650 // MAP_GROWSDOWN:
651 // A special mmap() flag that is used to implement thread stacks. It tells
652 // kernel that the memory region should extend downwards when needed. This
653 // allows early versions of LinuxThreads to only mmap the first few pages
654 // when creating a new thread. Linux kernel will automatically expand thread
655 // stack as needed (on page faults).
656 //
657 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
658 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
659 // region, it's hard to tell if the fault is due to a legitimate stack
660 // access or because of reading/writing non-exist memory (e.g. buffer
661 // overrun). As a rule, if the fault happens below current stack pointer,
662 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
663 // application (see Linux kernel fault.c).
664 //
665 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
666 // stack overflow detection.
667 //
668 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
669 // not use this flag. However, the stack of initial thread is not created
670 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
671 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
672 // and then attach the thread to JVM.
673 //
674 // To get around the problem and allow stack banging on Linux, we need to
675 // manually expand thread stack after receiving the SIGSEGV.
676 //
677 // There are two ways to expand thread stack to address "bottom", we used
678 // both of them in JVM before 1.5:
679 // 1. adjust stack pointer first so that it is below "bottom", and then
680 // touch "bottom"
681 // 2. mmap() the page in question
682 //
683 // Now alternate signal stack is gone, it's harder to use 2. For instance,
684 // if current sp is already near the lower end of page 101, and we need to
685 // call mmap() to map page 100, it is possible that part of the mmap() frame
686 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
687 // That will destroy the mmap() frame and cause VM to crash.
688 //
689 // The following code works by adjusting sp first, then accessing the "bottom"
690 // page to force a page fault. Linux kernel will then automatically expand the
691 // stack mapping.
692 //
693 // _expand_stack_to() assumes its frame size is less than page size, which
694 // should always be true if the function is not inlined.
696 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
697 #define NOINLINE
698 #else
699 #define NOINLINE __attribute__ ((noinline))
700 #endif
702 static void _expand_stack_to(address bottom) NOINLINE;
704 static void _expand_stack_to(address bottom) {
705 address sp;
706 size_t size;
707 volatile char *p;
709 // Adjust bottom to point to the largest address within the same page, it
710 // gives us a one-page buffer if alloca() allocates slightly more memory.
711 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
712 bottom += os::Linux::page_size() - 1;
714 // sp might be slightly above current stack pointer; if that's the case, we
715 // will alloca() a little more space than necessary, which is OK. Don't use
716 // os::current_stack_pointer(), as its result can be slightly below current
717 // stack pointer, causing us to not alloca enough to reach "bottom".
718 sp = (address)&sp;
720 if (sp > bottom) {
721 size = sp - bottom;
722 p = (volatile char *)alloca(size);
723 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
724 p[0] = '\0';
725 }
726 }
728 void os::Linux::expand_stack_to(address bottom) {
729 _expand_stack_to(bottom);
730 }
732 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
733 assert(t!=NULL, "just checking");
734 assert(t->osthread()->expanding_stack(), "expand should be set");
735 assert(t->stack_base() != NULL, "stack_base was not initialized");
737 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
738 sigset_t mask_all, old_sigset;
739 sigfillset(&mask_all);
740 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
741 _expand_stack_to(addr);
742 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
743 return true;
744 }
745 return false;
746 }
748 //////////////////////////////////////////////////////////////////////////////
749 // create new thread
751 static address highest_vm_reserved_address();
753 // check if it's safe to start a new thread
754 static bool _thread_safety_check(Thread* thread) {
755 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
756 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
757 // Heap is mmap'ed at lower end of memory space. Thread stacks are
758 // allocated (MAP_FIXED) from high address space. Every thread stack
759 // occupies a fixed size slot (usually 2Mbytes, but user can change
760 // it to other values if they rebuild LinuxThreads).
761 //
762 // Problem with MAP_FIXED is that mmap() can still succeed even part of
763 // the memory region has already been mmap'ed. That means if we have too
764 // many threads and/or very large heap, eventually thread stack will
765 // collide with heap.
766 //
767 // Here we try to prevent heap/stack collision by comparing current
768 // stack bottom with the highest address that has been mmap'ed by JVM
769 // plus a safety margin for memory maps created by native code.
770 //
771 // This feature can be disabled by setting ThreadSafetyMargin to 0
772 //
773 if (ThreadSafetyMargin > 0) {
774 address stack_bottom = os::current_stack_base() - os::current_stack_size();
776 // not safe if our stack extends below the safety margin
777 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
778 } else {
779 return true;
780 }
781 } else {
782 // Floating stack LinuxThreads or NPTL:
783 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
784 // there's not enough space left, pthread_create() will fail. If we come
785 // here, that means enough space has been reserved for stack.
786 return true;
787 }
788 }
790 // Thread start routine for all newly created threads
791 static void *java_start(Thread *thread) {
792 // Try to randomize the cache line index of hot stack frames.
793 // This helps when threads of the same stack traces evict each other's
794 // cache lines. The threads can be either from the same JVM instance, or
795 // from different JVM instances. The benefit is especially true for
796 // processors with hyperthreading technology.
797 static int counter = 0;
798 int pid = os::current_process_id();
799 alloca(((pid ^ counter++) & 7) * 128);
801 ThreadLocalStorage::set_thread(thread);
803 OSThread* osthread = thread->osthread();
804 Monitor* sync = osthread->startThread_lock();
806 // non floating stack LinuxThreads needs extra check, see above
807 if (!_thread_safety_check(thread)) {
808 // notify parent thread
809 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
810 osthread->set_state(ZOMBIE);
811 sync->notify_all();
812 return NULL;
813 }
815 // thread_id is kernel thread id (similar to Solaris LWP id)
816 osthread->set_thread_id(os::Linux::gettid());
818 if (UseNUMA) {
819 int lgrp_id = os::numa_get_group_id();
820 if (lgrp_id != -1) {
821 thread->set_lgrp_id(lgrp_id);
822 }
823 }
824 // initialize signal mask for this thread
825 os::Linux::hotspot_sigmask(thread);
827 // initialize floating point control register
828 os::Linux::init_thread_fpu_state();
830 // handshaking with parent thread
831 {
832 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
834 // notify parent thread
835 osthread->set_state(INITIALIZED);
836 sync->notify_all();
838 // wait until os::start_thread()
839 while (osthread->get_state() == INITIALIZED) {
840 sync->wait(Mutex::_no_safepoint_check_flag);
841 }
842 }
844 // call one more level start routine
845 thread->run();
847 return 0;
848 }
850 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
851 assert(thread->osthread() == NULL, "caller responsible");
853 // Allocate the OSThread object
854 OSThread* osthread = new OSThread(NULL, NULL);
855 if (osthread == NULL) {
856 return false;
857 }
859 // set the correct thread state
860 osthread->set_thread_type(thr_type);
862 // Initial state is ALLOCATED but not INITIALIZED
863 osthread->set_state(ALLOCATED);
865 thread->set_osthread(osthread);
867 // init thread attributes
868 pthread_attr_t attr;
869 pthread_attr_init(&attr);
870 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
872 // stack size
873 if (os::Linux::supports_variable_stack_size()) {
874 // calculate stack size if it's not specified by caller
875 if (stack_size == 0) {
876 stack_size = os::Linux::default_stack_size(thr_type);
878 switch (thr_type) {
879 case os::java_thread:
880 // Java threads use ThreadStackSize which default value can be
881 // changed with the flag -Xss
882 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
883 stack_size = JavaThread::stack_size_at_create();
884 break;
885 case os::compiler_thread:
886 if (CompilerThreadStackSize > 0) {
887 stack_size = (size_t)(CompilerThreadStackSize * K);
888 break;
889 } // else fall through:
890 // use VMThreadStackSize if CompilerThreadStackSize is not defined
891 case os::vm_thread:
892 case os::pgc_thread:
893 case os::cgc_thread:
894 case os::watcher_thread:
895 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
896 break;
897 }
898 }
900 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
901 pthread_attr_setstacksize(&attr, stack_size);
902 } else {
903 // let pthread_create() pick the default value.
904 }
906 // glibc guard page
907 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
909 ThreadState state;
911 {
912 // Serialize thread creation if we are running with fixed stack LinuxThreads
913 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
914 if (lock) {
915 os::Linux::createThread_lock()->lock_without_safepoint_check();
916 }
918 pthread_t tid;
919 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
921 pthread_attr_destroy(&attr);
923 if (ret != 0) {
924 if (PrintMiscellaneous && (Verbose || WizardMode)) {
925 perror("pthread_create()");
926 }
927 // Need to clean up stuff we've allocated so far
928 thread->set_osthread(NULL);
929 delete osthread;
930 if (lock) os::Linux::createThread_lock()->unlock();
931 return false;
932 }
934 // Store pthread info into the OSThread
935 osthread->set_pthread_id(tid);
937 // Wait until child thread is either initialized or aborted
938 {
939 Monitor* sync_with_child = osthread->startThread_lock();
940 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
941 while ((state = osthread->get_state()) == ALLOCATED) {
942 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
943 }
944 }
946 if (lock) {
947 os::Linux::createThread_lock()->unlock();
948 }
949 }
951 // Aborted due to thread limit being reached
952 if (state == ZOMBIE) {
953 thread->set_osthread(NULL);
954 delete osthread;
955 return false;
956 }
958 // The thread is returned suspended (in state INITIALIZED),
959 // and is started higher up in the call chain
960 assert(state == INITIALIZED, "race condition");
961 return true;
962 }
964 /////////////////////////////////////////////////////////////////////////////
965 // attach existing thread
967 // bootstrap the main thread
968 bool os::create_main_thread(JavaThread* thread) {
969 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
970 return create_attached_thread(thread);
971 }
973 bool os::create_attached_thread(JavaThread* thread) {
974 #ifdef ASSERT
975 thread->verify_not_published();
976 #endif
978 // Allocate the OSThread object
979 OSThread* osthread = new OSThread(NULL, NULL);
981 if (osthread == NULL) {
982 return false;
983 }
985 // Store pthread info into the OSThread
986 osthread->set_thread_id(os::Linux::gettid());
987 osthread->set_pthread_id(::pthread_self());
989 // initialize floating point control register
990 os::Linux::init_thread_fpu_state();
992 // Initial thread state is RUNNABLE
993 osthread->set_state(RUNNABLE);
995 thread->set_osthread(osthread);
997 if (UseNUMA) {
998 int lgrp_id = os::numa_get_group_id();
999 if (lgrp_id != -1) {
1000 thread->set_lgrp_id(lgrp_id);
1001 }
1002 }
1004 if (os::is_primordial_thread()) {
1005 // If current thread is primordial thread, its stack is mapped on demand,
1006 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1007 // the entire stack region to avoid SEGV in stack banging.
1008 // It is also useful to get around the heap-stack-gap problem on SuSE
1009 // kernel (see 4821821 for details). We first expand stack to the top
1010 // of yellow zone, then enable stack yellow zone (order is significant,
1011 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1012 // is no gap between the last two virtual memory regions.
1014 JavaThread *jt = (JavaThread *)thread;
1015 address addr = jt->stack_yellow_zone_base();
1016 assert(addr != NULL, "initialization problem?");
1017 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1019 osthread->set_expanding_stack();
1020 os::Linux::manually_expand_stack(jt, addr);
1021 osthread->clear_expanding_stack();
1022 }
1024 // initialize signal mask for this thread
1025 // and save the caller's signal mask
1026 os::Linux::hotspot_sigmask(thread);
1028 return true;
1029 }
1031 void os::pd_start_thread(Thread* thread) {
1032 OSThread * osthread = thread->osthread();
1033 assert(osthread->get_state() != INITIALIZED, "just checking");
1034 Monitor* sync_with_child = osthread->startThread_lock();
1035 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1036 sync_with_child->notify();
1037 }
1039 // Free Linux resources related to the OSThread
1040 void os::free_thread(OSThread* osthread) {
1041 assert(osthread != NULL, "osthread not set");
1043 if (Thread::current()->osthread() == osthread) {
1044 // Restore caller's signal mask
1045 sigset_t sigmask = osthread->caller_sigmask();
1046 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1047 }
1049 delete osthread;
1050 }
1052 //////////////////////////////////////////////////////////////////////////////
1053 // thread local storage
1055 // Restore the thread pointer if the destructor is called. This is in case
1056 // someone from JNI code sets up a destructor with pthread_key_create to run
1057 // detachCurrentThread on thread death. Unless we restore the thread pointer we
1058 // will hang or crash. When detachCurrentThread is called the key will be set
1059 // to null and we will not be called again. If detachCurrentThread is never
1060 // called we could loop forever depending on the pthread implementation.
1061 static void restore_thread_pointer(void* p) {
1062 Thread* thread = (Thread*) p;
1063 os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
1064 }
1066 int os::allocate_thread_local_storage() {
1067 pthread_key_t key;
1068 int rslt = pthread_key_create(&key, restore_thread_pointer);
1069 assert(rslt == 0, "cannot allocate thread local storage");
1070 return (int)key;
1071 }
1073 // Note: This is currently not used by VM, as we don't destroy TLS key
1074 // on VM exit.
1075 void os::free_thread_local_storage(int index) {
1076 int rslt = pthread_key_delete((pthread_key_t)index);
1077 assert(rslt == 0, "invalid index");
1078 }
1080 void os::thread_local_storage_at_put(int index, void* value) {
1081 int rslt = pthread_setspecific((pthread_key_t)index, value);
1082 assert(rslt == 0, "pthread_setspecific failed");
1083 }
1085 extern "C" Thread* get_thread() {
1086 return ThreadLocalStorage::thread();
1087 }
1089 //////////////////////////////////////////////////////////////////////////////
1090 // primordial thread
1092 // Check if current thread is the primordial thread, similar to Solaris thr_main.
1093 bool os::is_primordial_thread(void) {
1094 char dummy;
1095 // If called before init complete, thread stack bottom will be null.
1096 // Can be called if fatal error occurs before initialization.
1097 if (os::Linux::initial_thread_stack_bottom() == NULL) return false;
1098 assert(os::Linux::initial_thread_stack_bottom() != NULL &&
1099 os::Linux::initial_thread_stack_size() != 0,
1100 "os::init did not locate primordial thread's stack region");
1101 if ((address)&dummy >= os::Linux::initial_thread_stack_bottom() &&
1102 (address)&dummy < os::Linux::initial_thread_stack_bottom() +
1103 os::Linux::initial_thread_stack_size()) {
1104 return true;
1105 } else {
1106 return false;
1107 }
1108 }
1110 // Find the virtual memory area that contains addr
1111 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1112 FILE *fp = fopen("/proc/self/maps", "r");
1113 if (fp) {
1114 address low, high;
1115 while (!feof(fp)) {
1116 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1117 if (low <= addr && addr < high) {
1118 if (vma_low) *vma_low = low;
1119 if (vma_high) *vma_high = high;
1120 fclose (fp);
1121 return true;
1122 }
1123 }
1124 for (;;) {
1125 int ch = fgetc(fp);
1126 if (ch == EOF || ch == (int)'\n') break;
1127 }
1128 }
1129 fclose(fp);
1130 }
1131 return false;
1132 }
1134 // Locate primordial thread stack. This special handling of primordial thread stack
1135 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1136 // bogus value for the primordial process thread. While the launcher has created
1137 // the VM in a new thread since JDK 6, we still have to allow for the use of the
1138 // JNI invocation API from a primordial thread.
1139 void os::Linux::capture_initial_stack(size_t max_size) {
1141 // max_size is either 0 (which means accept OS default for thread stacks) or
1142 // a user-specified value known to be at least the minimum needed. If we
1143 // are actually on the primordial thread we can make it appear that we have a
1144 // smaller max_size stack by inserting the guard pages at that location. But we
1145 // cannot do anything to emulate a larger stack than what has been provided by
1146 // the OS or threading library. In fact if we try to use a stack greater than
1147 // what is set by rlimit then we will crash the hosting process.
1149 // Maximum stack size is the easy part, get it from RLIMIT_STACK.
1150 // If this is "unlimited" then it will be a huge value.
1151 struct rlimit rlim;
1152 getrlimit(RLIMIT_STACK, &rlim);
1153 size_t stack_size = rlim.rlim_cur;
1155 // 6308388: a bug in ld.so will relocate its own .data section to the
1156 // lower end of primordial stack; reduce ulimit -s value a little bit
1157 // so we won't install guard page on ld.so's data section.
1158 // But ensure we don't underflow the stack size - allow 1 page spare
1159 if (stack_size >= (size_t)(3 * page_size())) {
1160 stack_size -= 2 * page_size();
1161 }
1163 // Try to figure out where the stack base (top) is. This is harder.
1164 //
1165 // When an application is started, glibc saves the initial stack pointer in
1166 // a global variable "__libc_stack_end", which is then used by system
1167 // libraries. __libc_stack_end should be pretty close to stack top. The
1168 // variable is available since the very early days. However, because it is
1169 // a private interface, it could disappear in the future.
1170 //
1171 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1172 // to __libc_stack_end, it is very close to stack top, but isn't the real
1173 // stack top. Note that /proc may not exist if VM is running as a chroot
1174 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1175 // /proc/<pid>/stat could change in the future (though unlikely).
1176 //
1177 // We try __libc_stack_end first. If that doesn't work, look for
1178 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1179 // as a hint, which should work well in most cases.
1181 uintptr_t stack_start;
1183 // try __libc_stack_end first
1184 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1185 if (p && *p) {
1186 stack_start = *p;
1187 } else {
1188 // see if we can get the start_stack field from /proc/self/stat
1189 FILE *fp;
1190 int pid;
1191 char state;
1192 int ppid;
1193 int pgrp;
1194 int session;
1195 int nr;
1196 int tpgrp;
1197 unsigned long flags;
1198 unsigned long minflt;
1199 unsigned long cminflt;
1200 unsigned long majflt;
1201 unsigned long cmajflt;
1202 unsigned long utime;
1203 unsigned long stime;
1204 long cutime;
1205 long cstime;
1206 long prio;
1207 long nice;
1208 long junk;
1209 long it_real;
1210 uintptr_t start;
1211 uintptr_t vsize;
1212 intptr_t rss;
1213 uintptr_t rsslim;
1214 uintptr_t scodes;
1215 uintptr_t ecode;
1216 int i;
1218 // Figure what the primordial thread stack base is. Code is inspired
1219 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1220 // followed by command name surrounded by parentheses, state, etc.
1221 char stat[2048];
1222 int statlen;
1224 fp = fopen("/proc/self/stat", "r");
1225 if (fp) {
1226 statlen = fread(stat, 1, 2047, fp);
1227 stat[statlen] = '\0';
1228 fclose(fp);
1230 // Skip pid and the command string. Note that we could be dealing with
1231 // weird command names, e.g. user could decide to rename java launcher
1232 // to "java 1.4.2 :)", then the stat file would look like
1233 // 1234 (java 1.4.2 :)) R ... ...
1234 // We don't really need to know the command string, just find the last
1235 // occurrence of ")" and then start parsing from there. See bug 4726580.
1236 char * s = strrchr(stat, ')');
1238 i = 0;
1239 if (s) {
1240 // Skip blank chars
1241 do s++; while (isspace(*s));
1243 #define _UFM UINTX_FORMAT
1244 #define _DFM INTX_FORMAT
1246 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1247 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1248 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld " _UFM _UFM _DFM _UFM _UFM _UFM _UFM,
1249 &state, /* 3 %c */
1250 &ppid, /* 4 %d */
1251 &pgrp, /* 5 %d */
1252 &session, /* 6 %d */
1253 &nr, /* 7 %d */
1254 &tpgrp, /* 8 %d */
1255 &flags, /* 9 %lu */
1256 &minflt, /* 10 %lu */
1257 &cminflt, /* 11 %lu */
1258 &majflt, /* 12 %lu */
1259 &cmajflt, /* 13 %lu */
1260 &utime, /* 14 %lu */
1261 &stime, /* 15 %lu */
1262 &cutime, /* 16 %ld */
1263 &cstime, /* 17 %ld */
1264 &prio, /* 18 %ld */
1265 &nice, /* 19 %ld */
1266 &junk, /* 20 %ld */
1267 &it_real, /* 21 %ld */
1268 &start, /* 22 UINTX_FORMAT */
1269 &vsize, /* 23 UINTX_FORMAT */
1270 &rss, /* 24 INTX_FORMAT */
1271 &rsslim, /* 25 UINTX_FORMAT */
1272 &scodes, /* 26 UINTX_FORMAT */
1273 &ecode, /* 27 UINTX_FORMAT */
1274 &stack_start); /* 28 UINTX_FORMAT */
1275 }
1277 #undef _UFM
1278 #undef _DFM
1280 if (i != 28 - 2) {
1281 assert(false, "Bad conversion from /proc/self/stat");
1282 // product mode - assume we are the primordial thread, good luck in the
1283 // embedded case.
1284 warning("Can't detect primordial thread stack location - bad conversion");
1285 stack_start = (uintptr_t) &rlim;
1286 }
1287 } else {
1288 // For some reason we can't open /proc/self/stat (for example, running on
1289 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1290 // most cases, so don't abort:
1291 warning("Can't detect primordial thread stack location - no /proc/self/stat");
1292 stack_start = (uintptr_t) &rlim;
1293 }
1294 }
1296 // Now we have a pointer (stack_start) very close to the stack top, the
1297 // next thing to do is to figure out the exact location of stack top. We
1298 // can find out the virtual memory area that contains stack_start by
1299 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1300 // and its upper limit is the real stack top. (again, this would fail if
1301 // running inside chroot, because /proc may not exist.)
1303 uintptr_t stack_top;
1304 address low, high;
1305 if (find_vma((address)stack_start, &low, &high)) {
1306 // success, "high" is the true stack top. (ignore "low", because initial
1307 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1308 stack_top = (uintptr_t)high;
1309 } else {
1310 // failed, likely because /proc/self/maps does not exist
1311 warning("Can't detect primordial thread stack location - find_vma failed");
1312 // best effort: stack_start is normally within a few pages below the real
1313 // stack top, use it as stack top, and reduce stack size so we won't put
1314 // guard page outside stack.
1315 stack_top = stack_start;
1316 stack_size -= 16 * page_size();
1317 }
1319 // stack_top could be partially down the page so align it
1320 stack_top = align_size_up(stack_top, page_size());
1322 // Allowed stack value is minimum of max_size and what we derived from rlimit
1323 if (max_size > 0) {
1324 _initial_thread_stack_size = MIN2(max_size, stack_size);
1325 } else {
1326 // Accept the rlimit max, but if stack is unlimited then it will be huge, so
1327 // clamp it at 8MB as we do on Solaris
1328 _initial_thread_stack_size = MIN2(stack_size, 8*M);
1329 }
1331 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1332 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1333 assert(_initial_thread_stack_bottom < (address)stack_top, "overflow!");
1334 }
1336 ////////////////////////////////////////////////////////////////////////////////
1337 // time support
1339 // Time since start-up in seconds to a fine granularity.
1340 // Used by VMSelfDestructTimer and the MemProfiler.
1341 double os::elapsedTime() {
1343 return ((double)os::elapsed_counter()) / os::elapsed_frequency(); // nanosecond resolution
1344 }
1346 jlong os::elapsed_counter() {
1347 return javaTimeNanos() - initial_time_count;
1348 }
1350 jlong os::elapsed_frequency() {
1351 return NANOSECS_PER_SEC; // nanosecond resolution
1352 }
1354 bool os::supports_vtime() { return true; }
1355 bool os::enable_vtime() { return false; }
1356 bool os::vtime_enabled() { return false; }
1358 double os::elapsedVTime() {
1359 struct rusage usage;
1360 int retval = getrusage(RUSAGE_THREAD, &usage);
1361 if (retval == 0) {
1362 return (double) (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) + (double) (usage.ru_utime.tv_usec + usage.ru_stime.tv_usec) / (1000 * 1000);
1363 } else {
1364 // better than nothing, but not much
1365 return elapsedTime();
1366 }
1367 }
1369 jlong os::javaTimeMillis() {
1370 timeval time;
1371 int status = gettimeofday(&time, NULL);
1372 assert(status != -1, "linux error");
1373 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1374 }
1376 #ifndef CLOCK_MONOTONIC
1377 #define CLOCK_MONOTONIC (1)
1378 #endif
1380 void os::Linux::clock_init() {
1381 // we do dlopen's in this particular order due to bug in linux
1382 // dynamical loader (see 6348968) leading to crash on exit
1383 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1384 if (handle == NULL) {
1385 handle = dlopen("librt.so", RTLD_LAZY);
1386 }
1388 if (handle) {
1389 int (*clock_getres_func)(clockid_t, struct timespec*) =
1390 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1391 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1392 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1393 if (clock_getres_func && clock_gettime_func) {
1394 // See if monotonic clock is supported by the kernel. Note that some
1395 // early implementations simply return kernel jiffies (updated every
1396 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1397 // for nano time (though the monotonic property is still nice to have).
1398 // It's fixed in newer kernels, however clock_getres() still returns
1399 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1400 // resolution for now. Hopefully as people move to new kernels, this
1401 // won't be a problem.
1402 struct timespec res;
1403 struct timespec tp;
1404 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1405 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1406 // yes, monotonic clock is supported
1407 _clock_gettime = clock_gettime_func;
1408 return;
1409 } else {
1410 // close librt if there is no monotonic clock
1411 dlclose(handle);
1412 }
1413 }
1414 }
1415 warning("No monotonic clock was available - timed services may " \
1416 "be adversely affected if the time-of-day clock changes");
1417 }
1419 #ifndef SYS_clock_getres
1421 #if defined(IA32) || defined(AMD64)
1422 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1423 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1424 #else
1425 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1426 #define sys_clock_getres(x,y) -1
1427 #endif
1429 #else
1430 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1431 #endif
1433 void os::Linux::fast_thread_clock_init() {
1434 if (!UseLinuxPosixThreadCPUClocks) {
1435 return;
1436 }
1437 clockid_t clockid;
1438 struct timespec tp;
1439 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1440 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1442 // Switch to using fast clocks for thread cpu time if
1443 // the sys_clock_getres() returns 0 error code.
1444 // Note, that some kernels may support the current thread
1445 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1446 // returned by the pthread_getcpuclockid().
1447 // If the fast Posix clocks are supported then the sys_clock_getres()
1448 // must return at least tp.tv_sec == 0 which means a resolution
1449 // better than 1 sec. This is extra check for reliability.
1451 if(pthread_getcpuclockid_func &&
1452 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1453 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1455 _supports_fast_thread_cpu_time = true;
1456 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1457 }
1458 }
1460 jlong os::javaTimeNanos() {
1461 if (Linux::supports_monotonic_clock()) {
1462 struct timespec tp;
1463 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1464 assert(status == 0, "gettime error");
1465 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1466 return result;
1467 } else {
1468 timeval time;
1469 int status = gettimeofday(&time, NULL);
1470 assert(status != -1, "linux error");
1471 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1472 return 1000 * usecs;
1473 }
1474 }
1476 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1477 if (Linux::supports_monotonic_clock()) {
1478 info_ptr->max_value = ALL_64_BITS;
1480 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1481 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1482 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1483 } else {
1484 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1485 info_ptr->max_value = ALL_64_BITS;
1487 // gettimeofday is a real time clock so it skips
1488 info_ptr->may_skip_backward = true;
1489 info_ptr->may_skip_forward = true;
1490 }
1492 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1493 }
1495 // Return the real, user, and system times in seconds from an
1496 // arbitrary fixed point in the past.
1497 bool os::getTimesSecs(double* process_real_time,
1498 double* process_user_time,
1499 double* process_system_time) {
1500 struct tms ticks;
1501 clock_t real_ticks = times(&ticks);
1503 if (real_ticks == (clock_t) (-1)) {
1504 return false;
1505 } else {
1506 double ticks_per_second = (double) clock_tics_per_sec;
1507 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1508 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1509 *process_real_time = ((double) real_ticks) / ticks_per_second;
1511 return true;
1512 }
1513 }
1516 char * os::local_time_string(char *buf, size_t buflen) {
1517 struct tm t;
1518 time_t long_time;
1519 time(&long_time);
1520 localtime_r(&long_time, &t);
1521 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1522 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1523 t.tm_hour, t.tm_min, t.tm_sec);
1524 return buf;
1525 }
1527 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1528 return localtime_r(clock, res);
1529 }
1531 ////////////////////////////////////////////////////////////////////////////////
1532 // runtime exit support
1534 // Note: os::shutdown() might be called very early during initialization, or
1535 // called from signal handler. Before adding something to os::shutdown(), make
1536 // sure it is async-safe and can handle partially initialized VM.
1537 void os::shutdown() {
1539 // allow PerfMemory to attempt cleanup of any persistent resources
1540 perfMemory_exit();
1542 // needs to remove object in file system
1543 AttachListener::abort();
1545 // flush buffered output, finish log files
1546 ostream_abort();
1548 // Check for abort hook
1549 abort_hook_t abort_hook = Arguments::abort_hook();
1550 if (abort_hook != NULL) {
1551 abort_hook();
1552 }
1554 }
1556 // Note: os::abort() might be called very early during initialization, or
1557 // called from signal handler. Before adding something to os::abort(), make
1558 // sure it is async-safe and can handle partially initialized VM.
1559 void os::abort(bool dump_core) {
1560 os::shutdown();
1561 if (dump_core) {
1562 #ifndef PRODUCT
1563 fdStream out(defaultStream::output_fd());
1564 out.print_raw("Current thread is ");
1565 char buf[16];
1566 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1567 out.print_raw_cr(buf);
1568 out.print_raw_cr("Dumping core ...");
1569 #endif
1570 ::abort(); // dump core
1571 }
1573 ::exit(1);
1574 }
1576 // Die immediately, no exit hook, no abort hook, no cleanup.
1577 void os::die() {
1578 // _exit() on LinuxThreads only kills current thread
1579 ::abort();
1580 }
1583 // This method is a copy of JDK's sysGetLastErrorString
1584 // from src/solaris/hpi/src/system_md.c
1586 size_t os::lasterror(char *buf, size_t len) {
1588 if (errno == 0) return 0;
1590 const char *s = ::strerror(errno);
1591 size_t n = ::strlen(s);
1592 if (n >= len) {
1593 n = len - 1;
1594 }
1595 ::strncpy(buf, s, n);
1596 buf[n] = '\0';
1597 return n;
1598 }
1600 intx os::current_thread_id() { return (intx)pthread_self(); }
1601 int os::current_process_id() {
1603 // Under the old linux thread library, linux gives each thread
1604 // its own process id. Because of this each thread will return
1605 // a different pid if this method were to return the result
1606 // of getpid(2). Linux provides no api that returns the pid
1607 // of the launcher thread for the vm. This implementation
1608 // returns a unique pid, the pid of the launcher thread
1609 // that starts the vm 'process'.
1611 // Under the NPTL, getpid() returns the same pid as the
1612 // launcher thread rather than a unique pid per thread.
1613 // Use gettid() if you want the old pre NPTL behaviour.
1615 // if you are looking for the result of a call to getpid() that
1616 // returns a unique pid for the calling thread, then look at the
1617 // OSThread::thread_id() method in osThread_linux.hpp file
1619 return (int)(_initial_pid ? _initial_pid : getpid());
1620 }
1622 // DLL functions
1624 const char* os::dll_file_extension() { return ".so"; }
1626 // This must be hard coded because it's the system's temporary
1627 // directory not the java application's temp directory, ala java.io.tmpdir.
1628 const char* os::get_temp_directory() { return "/tmp"; }
1630 static bool file_exists(const char* filename) {
1631 struct stat statbuf;
1632 if (filename == NULL || strlen(filename) == 0) {
1633 return false;
1634 }
1635 return os::stat(filename, &statbuf) == 0;
1636 }
1638 bool os::dll_build_name(char* buffer, size_t buflen,
1639 const char* pname, const char* fname) {
1640 bool retval = false;
1641 // Copied from libhpi
1642 const size_t pnamelen = pname ? strlen(pname) : 0;
1644 // Return error on buffer overflow.
1645 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1646 return retval;
1647 }
1649 if (pnamelen == 0) {
1650 snprintf(buffer, buflen, "lib%s.so", fname);
1651 retval = true;
1652 } else if (strchr(pname, *os::path_separator()) != NULL) {
1653 int n;
1654 char** pelements = split_path(pname, &n);
1655 if (pelements == NULL) {
1656 return false;
1657 }
1658 for (int i = 0 ; i < n ; i++) {
1659 // Really shouldn't be NULL, but check can't hurt
1660 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1661 continue; // skip the empty path values
1662 }
1663 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1664 if (file_exists(buffer)) {
1665 retval = true;
1666 break;
1667 }
1668 }
1669 // release the storage
1670 for (int i = 0 ; i < n ; i++) {
1671 if (pelements[i] != NULL) {
1672 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1673 }
1674 }
1675 if (pelements != NULL) {
1676 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1677 }
1678 } else {
1679 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1680 retval = true;
1681 }
1682 return retval;
1683 }
1685 // check if addr is inside libjvm.so
1686 bool os::address_is_in_vm(address addr) {
1687 static address libjvm_base_addr;
1688 Dl_info dlinfo;
1690 if (libjvm_base_addr == NULL) {
1691 if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1692 libjvm_base_addr = (address)dlinfo.dli_fbase;
1693 }
1694 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1695 }
1697 if (dladdr((void *)addr, &dlinfo) != 0) {
1698 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1699 }
1701 return false;
1702 }
1704 bool os::dll_address_to_function_name(address addr, char *buf,
1705 int buflen, int *offset) {
1706 // buf is not optional, but offset is optional
1707 assert(buf != NULL, "sanity check");
1709 Dl_info dlinfo;
1711 if (dladdr((void*)addr, &dlinfo) != 0) {
1712 // see if we have a matching symbol
1713 if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1714 if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1715 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1716 }
1717 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1718 return true;
1719 }
1720 // no matching symbol so try for just file info
1721 if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1722 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1723 buf, buflen, offset, dlinfo.dli_fname)) {
1724 return true;
1725 }
1726 }
1727 }
1729 buf[0] = '\0';
1730 if (offset != NULL) *offset = -1;
1731 return false;
1732 }
1734 struct _address_to_library_name {
1735 address addr; // input : memory address
1736 size_t buflen; // size of fname
1737 char* fname; // output: library name
1738 address base; // library base addr
1739 };
1741 static int address_to_library_name_callback(struct dl_phdr_info *info,
1742 size_t size, void *data) {
1743 int i;
1744 bool found = false;
1745 address libbase = NULL;
1746 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1748 // iterate through all loadable segments
1749 for (i = 0; i < info->dlpi_phnum; i++) {
1750 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1751 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1752 // base address of a library is the lowest address of its loaded
1753 // segments.
1754 if (libbase == NULL || libbase > segbase) {
1755 libbase = segbase;
1756 }
1757 // see if 'addr' is within current segment
1758 if (segbase <= d->addr &&
1759 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1760 found = true;
1761 }
1762 }
1763 }
1765 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1766 // so dll_address_to_library_name() can fall through to use dladdr() which
1767 // can figure out executable name from argv[0].
1768 if (found && info->dlpi_name && info->dlpi_name[0]) {
1769 d->base = libbase;
1770 if (d->fname) {
1771 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1772 }
1773 return 1;
1774 }
1775 return 0;
1776 }
1778 bool os::dll_address_to_library_name(address addr, char* buf,
1779 int buflen, int* offset) {
1780 // buf is not optional, but offset is optional
1781 assert(buf != NULL, "sanity check");
1783 Dl_info dlinfo;
1784 struct _address_to_library_name data;
1786 // There is a bug in old glibc dladdr() implementation that it could resolve
1787 // to wrong library name if the .so file has a base address != NULL. Here
1788 // we iterate through the program headers of all loaded libraries to find
1789 // out which library 'addr' really belongs to. This workaround can be
1790 // removed once the minimum requirement for glibc is moved to 2.3.x.
1791 data.addr = addr;
1792 data.fname = buf;
1793 data.buflen = buflen;
1794 data.base = NULL;
1795 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1797 if (rslt) {
1798 // buf already contains library name
1799 if (offset) *offset = addr - data.base;
1800 return true;
1801 }
1802 if (dladdr((void*)addr, &dlinfo) != 0) {
1803 if (dlinfo.dli_fname != NULL) {
1804 jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1805 }
1806 if (dlinfo.dli_fbase != NULL && offset != NULL) {
1807 *offset = addr - (address)dlinfo.dli_fbase;
1808 }
1809 return true;
1810 }
1812 buf[0] = '\0';
1813 if (offset) *offset = -1;
1814 return false;
1815 }
1817 // Loads .dll/.so and
1818 // in case of error it checks if .dll/.so was built for the
1819 // same architecture as Hotspot is running on
1822 // Remember the stack's state. The Linux dynamic linker will change
1823 // the stack to 'executable' at most once, so we must safepoint only once.
1824 bool os::Linux::_stack_is_executable = false;
1826 // VM operation that loads a library. This is necessary if stack protection
1827 // of the Java stacks can be lost during loading the library. If we
1828 // do not stop the Java threads, they can stack overflow before the stacks
1829 // are protected again.
1830 class VM_LinuxDllLoad: public VM_Operation {
1831 private:
1832 const char *_filename;
1833 char *_ebuf;
1834 int _ebuflen;
1835 void *_lib;
1836 public:
1837 VM_LinuxDllLoad(const char *fn, char *ebuf, int ebuflen) :
1838 _filename(fn), _ebuf(ebuf), _ebuflen(ebuflen), _lib(NULL) {}
1839 VMOp_Type type() const { return VMOp_LinuxDllLoad; }
1840 void doit() {
1841 _lib = os::Linux::dll_load_in_vmthread(_filename, _ebuf, _ebuflen);
1842 os::Linux::_stack_is_executable = true;
1843 }
1844 void* loaded_library() { return _lib; }
1845 };
1847 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1848 {
1849 void * result = NULL;
1850 bool load_attempted = false;
1852 // Check whether the library to load might change execution rights
1853 // of the stack. If they are changed, the protection of the stack
1854 // guard pages will be lost. We need a safepoint to fix this.
1855 //
1856 // See Linux man page execstack(8) for more info.
1857 if (os::uses_stack_guard_pages() && !os::Linux::_stack_is_executable) {
1858 ElfFile ef(filename);
1859 if (!ef.specifies_noexecstack()) {
1860 if (!is_init_completed()) {
1861 os::Linux::_stack_is_executable = true;
1862 // This is OK - No Java threads have been created yet, and hence no
1863 // stack guard pages to fix.
1864 //
1865 // This should happen only when you are building JDK7 using a very
1866 // old version of JDK6 (e.g., with JPRT) and running test_gamma.
1867 //
1868 // Dynamic loader will make all stacks executable after
1869 // this function returns, and will not do that again.
1870 assert(Threads::first() == NULL, "no Java threads should exist yet.");
1871 } else {
1872 warning("You have loaded library %s which might have disabled stack guard. "
1873 "The VM will try to fix the stack guard now.\n"
1874 "It's highly recommended that you fix the library with "
1875 "'execstack -c <libfile>', or link it with '-z noexecstack'.",
1876 filename);
1878 assert(Thread::current()->is_Java_thread(), "must be Java thread");
1879 JavaThread *jt = JavaThread::current();
1880 if (jt->thread_state() != _thread_in_native) {
1881 // This happens when a compiler thread tries to load a hsdis-<arch>.so file
1882 // that requires ExecStack. Cannot enter safe point. Let's give up.
1883 warning("Unable to fix stack guard. Giving up.");
1884 } else {
1885 if (!LoadExecStackDllInVMThread) {
1886 // This is for the case where the DLL has an static
1887 // constructor function that executes JNI code. We cannot
1888 // load such DLLs in the VMThread.
1889 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1890 }
1892 ThreadInVMfromNative tiv(jt);
1893 debug_only(VMNativeEntryWrapper vew;)
1895 VM_LinuxDllLoad op(filename, ebuf, ebuflen);
1896 VMThread::execute(&op);
1897 if (LoadExecStackDllInVMThread) {
1898 result = op.loaded_library();
1899 }
1900 load_attempted = true;
1901 }
1902 }
1903 }
1904 }
1906 if (!load_attempted) {
1907 result = os::Linux::dlopen_helper(filename, ebuf, ebuflen);
1908 }
1910 if (result != NULL) {
1911 // Successful loading
1912 return result;
1913 }
1915 Elf32_Ehdr elf_head;
1916 int diag_msg_max_length=ebuflen-strlen(ebuf);
1917 char* diag_msg_buf=ebuf+strlen(ebuf);
1919 if (diag_msg_max_length==0) {
1920 // No more space in ebuf for additional diagnostics message
1921 return NULL;
1922 }
1925 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1927 if (file_descriptor < 0) {
1928 // Can't open library, report dlerror() message
1929 return NULL;
1930 }
1932 bool failed_to_read_elf_head=
1933 (sizeof(elf_head)!=
1934 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1936 ::close(file_descriptor);
1937 if (failed_to_read_elf_head) {
1938 // file i/o error - report dlerror() msg
1939 return NULL;
1940 }
1942 typedef struct {
1943 Elf32_Half code; // Actual value as defined in elf.h
1944 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1945 char elf_class; // 32 or 64 bit
1946 char endianess; // MSB or LSB
1947 char* name; // String representation
1948 } arch_t;
1950 #ifndef EM_486
1951 #define EM_486 6 /* Intel 80486 */
1952 #endif
1954 static const arch_t arch_array[]={
1955 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1956 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1957 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1958 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1959 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1960 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1961 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1962 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1963 #if defined(VM_LITTLE_ENDIAN)
1964 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2LSB, (char*)"Power PC 64 LE"},
1965 #else
1966 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1967 #endif
1968 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1969 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1970 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1971 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1972 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1973 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1974 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1975 };
1977 #if (defined IA32)
1978 static Elf32_Half running_arch_code=EM_386;
1979 #elif (defined AMD64)
1980 static Elf32_Half running_arch_code=EM_X86_64;
1981 #elif (defined IA64)
1982 static Elf32_Half running_arch_code=EM_IA_64;
1983 #elif (defined __sparc) && (defined _LP64)
1984 static Elf32_Half running_arch_code=EM_SPARCV9;
1985 #elif (defined __sparc) && (!defined _LP64)
1986 static Elf32_Half running_arch_code=EM_SPARC;
1987 #elif (defined __powerpc64__)
1988 static Elf32_Half running_arch_code=EM_PPC64;
1989 #elif (defined __powerpc__)
1990 static Elf32_Half running_arch_code=EM_PPC;
1991 #elif (defined ARM)
1992 static Elf32_Half running_arch_code=EM_ARM;
1993 #elif (defined S390)
1994 static Elf32_Half running_arch_code=EM_S390;
1995 #elif (defined ALPHA)
1996 static Elf32_Half running_arch_code=EM_ALPHA;
1997 #elif (defined MIPSEL)
1998 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1999 #elif (defined PARISC)
2000 static Elf32_Half running_arch_code=EM_PARISC;
2001 #elif (defined MIPS)
2002 static Elf32_Half running_arch_code=EM_MIPS;
2003 #elif (defined M68K)
2004 static Elf32_Half running_arch_code=EM_68K;
2005 #else
2006 #error Method os::dll_load requires that one of following is defined:\
2007 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
2008 #endif
2010 // Identify compatability class for VM's architecture and library's architecture
2011 // Obtain string descriptions for architectures
2013 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
2014 int running_arch_index=-1;
2016 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
2017 if (running_arch_code == arch_array[i].code) {
2018 running_arch_index = i;
2019 }
2020 if (lib_arch.code == arch_array[i].code) {
2021 lib_arch.compat_class = arch_array[i].compat_class;
2022 lib_arch.name = arch_array[i].name;
2023 }
2024 }
2026 assert(running_arch_index != -1,
2027 "Didn't find running architecture code (running_arch_code) in arch_array");
2028 if (running_arch_index == -1) {
2029 // Even though running architecture detection failed
2030 // we may still continue with reporting dlerror() message
2031 return NULL;
2032 }
2034 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
2035 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
2036 return NULL;
2037 }
2039 #ifndef S390
2040 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
2041 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
2042 return NULL;
2043 }
2044 #endif // !S390
2046 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
2047 if ( lib_arch.name!=NULL ) {
2048 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2049 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
2050 lib_arch.name, arch_array[running_arch_index].name);
2051 } else {
2052 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
2053 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
2054 lib_arch.code,
2055 arch_array[running_arch_index].name);
2056 }
2057 }
2059 return NULL;
2060 }
2062 void * os::Linux::dlopen_helper(const char *filename, char *ebuf, int ebuflen) {
2063 void * result = ::dlopen(filename, RTLD_LAZY);
2064 if (result == NULL) {
2065 ::strncpy(ebuf, ::dlerror(), ebuflen - 1);
2066 ebuf[ebuflen-1] = '\0';
2067 }
2068 return result;
2069 }
2071 void * os::Linux::dll_load_in_vmthread(const char *filename, char *ebuf, int ebuflen) {
2072 void * result = NULL;
2073 if (LoadExecStackDllInVMThread) {
2074 result = dlopen_helper(filename, ebuf, ebuflen);
2075 }
2077 // Since 7019808, libjvm.so is linked with -noexecstack. If the VM loads a
2078 // library that requires an executable stack, or which does not have this
2079 // stack attribute set, dlopen changes the stack attribute to executable. The
2080 // read protection of the guard pages gets lost.
2081 //
2082 // Need to check _stack_is_executable again as multiple VM_LinuxDllLoad
2083 // may have been queued at the same time.
2085 if (!_stack_is_executable) {
2086 JavaThread *jt = Threads::first();
2088 while (jt) {
2089 if (!jt->stack_guard_zone_unused() && // Stack not yet fully initialized
2090 jt->stack_yellow_zone_enabled()) { // No pending stack overflow exceptions
2091 if (!os::guard_memory((char *) jt->stack_red_zone_base() - jt->stack_red_zone_size(),
2092 jt->stack_yellow_zone_size() + jt->stack_red_zone_size())) {
2093 warning("Attempt to reguard stack yellow zone failed.");
2094 }
2095 }
2096 jt = jt->next();
2097 }
2098 }
2100 return result;
2101 }
2103 /*
2104 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
2105 * chances are you might want to run the generated bits against glibc-2.0
2106 * libdl.so, so always use locking for any version of glibc.
2107 */
2108 void* os::dll_lookup(void* handle, const char* name) {
2109 pthread_mutex_lock(&dl_mutex);
2110 void* res = dlsym(handle, name);
2111 pthread_mutex_unlock(&dl_mutex);
2112 return res;
2113 }
2115 void* os::get_default_process_handle() {
2116 return (void*)::dlopen(NULL, RTLD_LAZY);
2117 }
2119 static bool _print_ascii_file(const char* filename, outputStream* st) {
2120 int fd = ::open(filename, O_RDONLY);
2121 if (fd == -1) {
2122 return false;
2123 }
2125 char buf[32];
2126 int bytes;
2127 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
2128 st->print_raw(buf, bytes);
2129 }
2131 ::close(fd);
2133 return true;
2134 }
2136 void os::print_dll_info(outputStream *st) {
2137 st->print_cr("Dynamic libraries:");
2139 char fname[32];
2140 pid_t pid = os::Linux::gettid();
2142 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2144 if (!_print_ascii_file(fname, st)) {
2145 st->print("Can not get library information for pid = %d\n", pid);
2146 }
2147 }
2149 int os::get_loaded_modules_info(os::LoadedModulesCallbackFunc callback, void *param) {
2150 FILE *procmapsFile = NULL;
2152 // Open the procfs maps file for the current process
2153 if ((procmapsFile = fopen("/proc/self/maps", "r")) != NULL) {
2154 // Allocate PATH_MAX for file name plus a reasonable size for other fields.
2155 char line[PATH_MAX + 100];
2157 // Read line by line from 'file'
2158 while (fgets(line, sizeof(line), procmapsFile) != NULL) {
2159 u8 base, top, offset, inode;
2160 char permissions[5];
2161 char device[6];
2162 char name[PATH_MAX + 1];
2164 // Parse fields from line
2165 sscanf(line, UINT64_FORMAT_X "-" UINT64_FORMAT_X " %4s " UINT64_FORMAT_X " %7s " INT64_FORMAT " %s",
2166 &base, &top, permissions, &offset, device, &inode, name);
2168 // Filter by device id '00:00' so that we only get file system mapped files.
2169 if (strcmp(device, "00:00") != 0) {
2171 // Call callback with the fields of interest
2172 if(callback(name, (address)base, (address)top, param)) {
2173 // Oops abort, callback aborted
2174 fclose(procmapsFile);
2175 return 1;
2176 }
2177 }
2178 }
2179 fclose(procmapsFile);
2180 }
2181 return 0;
2182 }
2184 void os::print_os_info_brief(outputStream* st) {
2185 os::Linux::print_distro_info(st);
2187 os::Posix::print_uname_info(st);
2189 os::Linux::print_libversion_info(st);
2191 }
2193 void os::print_os_info(outputStream* st) {
2194 st->print("OS:");
2196 os::Linux::print_distro_info(st);
2198 os::Posix::print_uname_info(st);
2200 // Print warning if unsafe chroot environment detected
2201 if (unsafe_chroot_detected) {
2202 st->print("WARNING!! ");
2203 st->print_cr("%s", unstable_chroot_error);
2204 }
2206 os::Linux::print_libversion_info(st);
2208 os::Posix::print_rlimit_info(st);
2210 os::Posix::print_load_average(st);
2212 os::Linux::print_full_memory_info(st);
2214 os::Linux::print_container_info(st);
2215 }
2217 // Try to identify popular distros.
2218 // Most Linux distributions have a /etc/XXX-release file, which contains
2219 // the OS version string. Newer Linux distributions have a /etc/lsb-release
2220 // file that also contains the OS version string. Some have more than one
2221 // /etc/XXX-release file (e.g. Mandrake has both /etc/mandrake-release and
2222 // /etc/redhat-release.), so the order is important.
2223 // Any Linux that is based on Redhat (i.e. Oracle, Mandrake, Sun JDS...) have
2224 // their own specific XXX-release file as well as a redhat-release file.
2225 // Because of this the XXX-release file needs to be searched for before the
2226 // redhat-release file.
2227 // Since Red Hat has a lsb-release file that is not very descriptive the
2228 // search for redhat-release needs to be before lsb-release.
2229 // Since the lsb-release file is the new standard it needs to be searched
2230 // before the older style release files.
2231 // Searching system-release (Red Hat) and os-release (other Linuxes) are a
2232 // next to last resort. The os-release file is a new standard that contains
2233 // distribution information and the system-release file seems to be an old
2234 // standard that has been replaced by the lsb-release and os-release files.
2235 // Searching for the debian_version file is the last resort. It contains
2236 // an informative string like "6.0.6" or "wheezy/sid". Because of this
2237 // "Debian " is printed before the contents of the debian_version file.
2238 void os::Linux::print_distro_info(outputStream* st) {
2239 if (!_print_ascii_file("/etc/oracle-release", st) &&
2240 !_print_ascii_file("/etc/mandriva-release", st) &&
2241 !_print_ascii_file("/etc/mandrake-release", st) &&
2242 !_print_ascii_file("/etc/sun-release", st) &&
2243 !_print_ascii_file("/etc/redhat-release", st) &&
2244 !_print_ascii_file("/etc/lsb-release", st) &&
2245 !_print_ascii_file("/etc/SuSE-release", st) &&
2246 !_print_ascii_file("/etc/turbolinux-release", st) &&
2247 !_print_ascii_file("/etc/gentoo-release", st) &&
2248 !_print_ascii_file("/etc/ltib-release", st) &&
2249 !_print_ascii_file("/etc/angstrom-version", st) &&
2250 !_print_ascii_file("/etc/system-release", st) &&
2251 !_print_ascii_file("/etc/os-release", st)) {
2253 if (file_exists("/etc/debian_version")) {
2254 st->print("Debian ");
2255 _print_ascii_file("/etc/debian_version", st);
2256 } else {
2257 st->print("Linux");
2258 }
2259 }
2260 st->cr();
2261 }
2263 void os::Linux::print_libversion_info(outputStream* st) {
2264 // libc, pthread
2265 st->print("libc:");
2266 st->print("%s ", os::Linux::glibc_version());
2267 st->print("%s ", os::Linux::libpthread_version());
2268 if (os::Linux::is_LinuxThreads()) {
2269 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2270 }
2271 st->cr();
2272 }
2274 void os::Linux::print_full_memory_info(outputStream* st) {
2275 st->print("\n/proc/meminfo:\n");
2276 _print_ascii_file("/proc/meminfo", st);
2277 st->cr();
2278 }
2280 void os::Linux::print_container_info(outputStream* st) {
2281 if (!OSContainer::is_containerized()) {
2282 return;
2283 }
2285 st->print("container (cgroup) information:\n");
2287 const char *p_ct = OSContainer::container_type();
2288 st->print("container_type: %s\n", p_ct != NULL ? p_ct : "failed");
2290 char *p = OSContainer::cpu_cpuset_cpus();
2291 st->print("cpu_cpuset_cpus: %s\n", p != NULL ? p : "failed");
2292 free(p);
2294 p = OSContainer::cpu_cpuset_memory_nodes();
2295 st->print("cpu_memory_nodes: %s\n", p != NULL ? p : "failed");
2296 free(p);
2298 int i = OSContainer::active_processor_count();
2299 if (i > 0) {
2300 st->print("active_processor_count: %d\n", i);
2301 } else {
2302 st->print("active_processor_count: failed\n");
2303 }
2305 i = OSContainer::cpu_quota();
2306 st->print("cpu_quota: %d\n", i);
2308 i = OSContainer::cpu_period();
2309 st->print("cpu_period: %d\n", i);
2311 i = OSContainer::cpu_shares();
2312 st->print("cpu_shares: %d\n", i);
2314 jlong j = OSContainer::memory_limit_in_bytes();
2315 st->print("memory_limit_in_bytes: " JLONG_FORMAT "\n", j);
2317 j = OSContainer::memory_and_swap_limit_in_bytes();
2318 st->print("memory_and_swap_limit_in_bytes: " JLONG_FORMAT "\n", j);
2320 j = OSContainer::memory_soft_limit_in_bytes();
2321 st->print("memory_soft_limit_in_bytes: " JLONG_FORMAT "\n", j);
2323 j = OSContainer::OSContainer::memory_usage_in_bytes();
2324 st->print("memory_usage_in_bytes: " JLONG_FORMAT "\n", j);
2326 j = OSContainer::OSContainer::memory_max_usage_in_bytes();
2327 st->print("memory_max_usage_in_bytes: " JLONG_FORMAT "\n", j);
2328 st->cr();
2329 }
2331 void os::print_memory_info(outputStream* st) {
2333 st->print("Memory:");
2334 st->print(" %dk page", os::vm_page_size()>>10);
2336 // values in struct sysinfo are "unsigned long"
2337 struct sysinfo si;
2338 sysinfo(&si);
2340 st->print(", physical " UINT64_FORMAT "k",
2341 os::physical_memory() >> 10);
2342 st->print("(" UINT64_FORMAT "k free)",
2343 os::available_memory() >> 10);
2344 st->print(", swap " UINT64_FORMAT "k",
2345 ((jlong)si.totalswap * si.mem_unit) >> 10);
2346 st->print("(" UINT64_FORMAT "k free)",
2347 ((jlong)si.freeswap * si.mem_unit) >> 10);
2348 st->cr();
2349 }
2351 void os::pd_print_cpu_info(outputStream* st) {
2352 st->print("\n/proc/cpuinfo:\n");
2353 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2354 st->print(" <Not Available>");
2355 }
2356 st->cr();
2357 }
2359 void os::print_siginfo(outputStream* st, void* siginfo) {
2360 const siginfo_t* si = (const siginfo_t*)siginfo;
2362 os::Posix::print_siginfo_brief(st, si);
2363 #if INCLUDE_CDS
2364 if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2365 UseSharedSpaces) {
2366 FileMapInfo* mapinfo = FileMapInfo::current_info();
2367 if (mapinfo->is_in_shared_space(si->si_addr)) {
2368 st->print("\n\nError accessing class data sharing archive." \
2369 " Mapped file inaccessible during execution, " \
2370 " possible disk/network problem.");
2371 }
2372 }
2373 #endif
2374 st->cr();
2375 }
2378 static void print_signal_handler(outputStream* st, int sig,
2379 char* buf, size_t buflen);
2381 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2382 st->print_cr("Signal Handlers:");
2383 print_signal_handler(st, SIGSEGV, buf, buflen);
2384 print_signal_handler(st, SIGBUS , buf, buflen);
2385 print_signal_handler(st, SIGFPE , buf, buflen);
2386 print_signal_handler(st, SIGPIPE, buf, buflen);
2387 print_signal_handler(st, SIGXFSZ, buf, buflen);
2388 print_signal_handler(st, SIGILL , buf, buflen);
2389 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2390 print_signal_handler(st, SR_signum, buf, buflen);
2391 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2392 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2393 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2394 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2395 #if defined(PPC64)
2396 print_signal_handler(st, SIGTRAP, buf, buflen);
2397 #endif
2398 }
2400 static char saved_jvm_path[MAXPATHLEN] = {0};
2402 // Find the full path to the current module, libjvm.so
2403 void os::jvm_path(char *buf, jint buflen) {
2404 // Error checking.
2405 if (buflen < MAXPATHLEN) {
2406 assert(false, "must use a large-enough buffer");
2407 buf[0] = '\0';
2408 return;
2409 }
2410 // Lazy resolve the path to current module.
2411 if (saved_jvm_path[0] != 0) {
2412 strcpy(buf, saved_jvm_path);
2413 return;
2414 }
2416 char dli_fname[MAXPATHLEN];
2417 bool ret = dll_address_to_library_name(
2418 CAST_FROM_FN_PTR(address, os::jvm_path),
2419 dli_fname, sizeof(dli_fname), NULL);
2420 assert(ret, "cannot locate libjvm");
2421 char *rp = NULL;
2422 if (ret && dli_fname[0] != '\0') {
2423 rp = realpath(dli_fname, buf);
2424 }
2425 if (rp == NULL)
2426 return;
2428 if (Arguments::created_by_gamma_launcher()) {
2429 // Support for the gamma launcher. Typical value for buf is
2430 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2431 // the right place in the string, then assume we are installed in a JDK and
2432 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2433 // up the path so it looks like libjvm.so is installed there (append a
2434 // fake suffix hotspot/libjvm.so).
2435 const char *p = buf + strlen(buf) - 1;
2436 for (int count = 0; p > buf && count < 5; ++count) {
2437 for (--p; p > buf && *p != '/'; --p)
2438 /* empty */ ;
2439 }
2441 if (strncmp(p, "/jre/lib/", 9) != 0) {
2442 // Look for JAVA_HOME in the environment.
2443 char* java_home_var = ::getenv("JAVA_HOME");
2444 if (java_home_var != NULL && java_home_var[0] != 0) {
2445 char* jrelib_p;
2446 int len;
2448 // Check the current module name "libjvm.so".
2449 p = strrchr(buf, '/');
2450 assert(strstr(p, "/libjvm") == p, "invalid library name");
2452 rp = realpath(java_home_var, buf);
2453 if (rp == NULL)
2454 return;
2456 // determine if this is a legacy image or modules image
2457 // modules image doesn't have "jre" subdirectory
2458 len = strlen(buf);
2459 assert(len < buflen, "Ran out of buffer room");
2460 jrelib_p = buf + len;
2461 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2462 if (0 != access(buf, F_OK)) {
2463 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2464 }
2466 if (0 == access(buf, F_OK)) {
2467 // Use current module name "libjvm.so"
2468 len = strlen(buf);
2469 snprintf(buf + len, buflen-len, "/hotspot/libjvm.so");
2470 } else {
2471 // Go back to path of .so
2472 rp = realpath(dli_fname, buf);
2473 if (rp == NULL)
2474 return;
2475 }
2476 }
2477 }
2478 }
2480 strncpy(saved_jvm_path, buf, MAXPATHLEN);
2481 }
2483 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2484 // no prefix required, not even "_"
2485 }
2487 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2488 // no suffix required
2489 }
2491 ////////////////////////////////////////////////////////////////////////////////
2492 // sun.misc.Signal support
2494 static volatile jint sigint_count = 0;
2496 static void
2497 UserHandler(int sig, void *siginfo, void *context) {
2498 // 4511530 - sem_post is serialized and handled by the manager thread. When
2499 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2500 // don't want to flood the manager thread with sem_post requests.
2501 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2502 return;
2504 // Ctrl-C is pressed during error reporting, likely because the error
2505 // handler fails to abort. Let VM die immediately.
2506 if (sig == SIGINT && is_error_reported()) {
2507 os::die();
2508 }
2510 os::signal_notify(sig);
2511 }
2513 void* os::user_handler() {
2514 return CAST_FROM_FN_PTR(void*, UserHandler);
2515 }
2517 class Semaphore : public StackObj {
2518 public:
2519 Semaphore();
2520 ~Semaphore();
2521 void signal();
2522 void wait();
2523 bool trywait();
2524 bool timedwait(unsigned int sec, int nsec);
2525 private:
2526 sem_t _semaphore;
2527 };
2529 Semaphore::Semaphore() {
2530 sem_init(&_semaphore, 0, 0);
2531 }
2533 Semaphore::~Semaphore() {
2534 sem_destroy(&_semaphore);
2535 }
2537 void Semaphore::signal() {
2538 sem_post(&_semaphore);
2539 }
2541 void Semaphore::wait() {
2542 sem_wait(&_semaphore);
2543 }
2545 bool Semaphore::trywait() {
2546 return sem_trywait(&_semaphore) == 0;
2547 }
2549 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2551 struct timespec ts;
2552 // Semaphore's are always associated with CLOCK_REALTIME
2553 os::Linux::clock_gettime(CLOCK_REALTIME, &ts);
2554 // see unpackTime for discussion on overflow checking
2555 if (sec >= MAX_SECS) {
2556 ts.tv_sec += MAX_SECS;
2557 ts.tv_nsec = 0;
2558 } else {
2559 ts.tv_sec += sec;
2560 ts.tv_nsec += nsec;
2561 if (ts.tv_nsec >= NANOSECS_PER_SEC) {
2562 ts.tv_nsec -= NANOSECS_PER_SEC;
2563 ++ts.tv_sec; // note: this must be <= max_secs
2564 }
2565 }
2567 while (1) {
2568 int result = sem_timedwait(&_semaphore, &ts);
2569 if (result == 0) {
2570 return true;
2571 } else if (errno == EINTR) {
2572 continue;
2573 } else if (errno == ETIMEDOUT) {
2574 return false;
2575 } else {
2576 return false;
2577 }
2578 }
2579 }
2581 extern "C" {
2582 typedef void (*sa_handler_t)(int);
2583 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2584 }
2586 void* os::signal(int signal_number, void* handler) {
2587 struct sigaction sigAct, oldSigAct;
2589 sigfillset(&(sigAct.sa_mask));
2590 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2591 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2593 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2594 // -1 means registration failed
2595 return (void *)-1;
2596 }
2598 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2599 }
2601 void os::signal_raise(int signal_number) {
2602 ::raise(signal_number);
2603 }
2605 /*
2606 * The following code is moved from os.cpp for making this
2607 * code platform specific, which it is by its very nature.
2608 */
2610 // Will be modified when max signal is changed to be dynamic
2611 int os::sigexitnum_pd() {
2612 return NSIG;
2613 }
2615 // a counter for each possible signal value
2616 static volatile jint pending_signals[NSIG+1] = { 0 };
2618 // Linux(POSIX) specific hand shaking semaphore.
2619 static sem_t sig_sem;
2620 static Semaphore sr_semaphore;
2622 void os::signal_init_pd() {
2623 // Initialize signal structures
2624 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2626 // Initialize signal semaphore
2627 ::sem_init(&sig_sem, 0, 0);
2628 }
2630 void os::signal_notify(int sig) {
2631 Atomic::inc(&pending_signals[sig]);
2632 ::sem_post(&sig_sem);
2633 }
2635 static int check_pending_signals(bool wait) {
2636 Atomic::store(0, &sigint_count);
2637 for (;;) {
2638 for (int i = 0; i < NSIG + 1; i++) {
2639 jint n = pending_signals[i];
2640 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2641 return i;
2642 }
2643 }
2644 if (!wait) {
2645 return -1;
2646 }
2647 JavaThread *thread = JavaThread::current();
2648 ThreadBlockInVM tbivm(thread);
2650 bool threadIsSuspended;
2651 do {
2652 thread->set_suspend_equivalent();
2653 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2654 ::sem_wait(&sig_sem);
2656 // were we externally suspended while we were waiting?
2657 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2658 if (threadIsSuspended) {
2659 //
2660 // The semaphore has been incremented, but while we were waiting
2661 // another thread suspended us. We don't want to continue running
2662 // while suspended because that would surprise the thread that
2663 // suspended us.
2664 //
2665 ::sem_post(&sig_sem);
2667 thread->java_suspend_self();
2668 }
2669 } while (threadIsSuspended);
2670 }
2671 }
2673 int os::signal_lookup() {
2674 return check_pending_signals(false);
2675 }
2677 int os::signal_wait() {
2678 return check_pending_signals(true);
2679 }
2681 ////////////////////////////////////////////////////////////////////////////////
2682 // Virtual Memory
2684 int os::vm_page_size() {
2685 // Seems redundant as all get out
2686 assert(os::Linux::page_size() != -1, "must call os::init");
2687 return os::Linux::page_size();
2688 }
2690 // Solaris allocates memory by pages.
2691 int os::vm_allocation_granularity() {
2692 assert(os::Linux::page_size() != -1, "must call os::init");
2693 return os::Linux::page_size();
2694 }
2696 // Rationale behind this function:
2697 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2698 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2699 // samples for JITted code. Here we create private executable mapping over the code cache
2700 // and then we can use standard (well, almost, as mapping can change) way to provide
2701 // info for the reporting script by storing timestamp and location of symbol
2702 void linux_wrap_code(char* base, size_t size) {
2703 static volatile jint cnt = 0;
2705 if (!UseOprofile) {
2706 return;
2707 }
2709 char buf[PATH_MAX+1];
2710 int num = Atomic::add(1, &cnt);
2712 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2713 os::get_temp_directory(), os::current_process_id(), num);
2714 unlink(buf);
2716 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2718 if (fd != -1) {
2719 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2720 if (rv != (off_t)-1) {
2721 if (::write(fd, "", 1) == 1) {
2722 mmap(base, size,
2723 PROT_READ|PROT_WRITE|PROT_EXEC,
2724 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2725 }
2726 }
2727 ::close(fd);
2728 unlink(buf);
2729 }
2730 }
2732 static bool recoverable_mmap_error(int err) {
2733 // See if the error is one we can let the caller handle. This
2734 // list of errno values comes from JBS-6843484. I can't find a
2735 // Linux man page that documents this specific set of errno
2736 // values so while this list currently matches Solaris, it may
2737 // change as we gain experience with this failure mode.
2738 switch (err) {
2739 case EBADF:
2740 case EINVAL:
2741 case ENOTSUP:
2742 // let the caller deal with these errors
2743 return true;
2745 default:
2746 // Any remaining errors on this OS can cause our reserved mapping
2747 // to be lost. That can cause confusion where different data
2748 // structures think they have the same memory mapped. The worst
2749 // scenario is if both the VM and a library think they have the
2750 // same memory mapped.
2751 return false;
2752 }
2753 }
2755 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2756 int err) {
2757 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2758 ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2759 strerror(err), err);
2760 }
2762 static void warn_fail_commit_memory(char* addr, size_t size,
2763 size_t alignment_hint, bool exec,
2764 int err) {
2765 warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2766 ", " SIZE_FORMAT ", %d) failed; error='%s' (errno=%d)", addr, size,
2767 alignment_hint, exec, strerror(err), err);
2768 }
2770 // NOTE: Linux kernel does not really reserve the pages for us.
2771 // All it does is to check if there are enough free pages
2772 // left at the time of mmap(). This could be a potential
2773 // problem.
2774 int os::Linux::commit_memory_impl(char* addr, size_t size, bool exec) {
2775 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2776 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2777 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2778 if (res != (uintptr_t) MAP_FAILED) {
2779 if (UseNUMAInterleaving) {
2780 numa_make_global(addr, size);
2781 }
2782 return 0;
2783 }
2785 int err = errno; // save errno from mmap() call above
2787 if (!recoverable_mmap_error(err)) {
2788 warn_fail_commit_memory(addr, size, exec, err);
2789 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, "committing reserved memory.");
2790 }
2792 return err;
2793 }
2795 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2796 return os::Linux::commit_memory_impl(addr, size, exec) == 0;
2797 }
2799 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2800 const char* mesg) {
2801 assert(mesg != NULL, "mesg must be specified");
2802 int err = os::Linux::commit_memory_impl(addr, size, exec);
2803 if (err != 0) {
2804 // the caller wants all commit errors to exit with the specified mesg:
2805 warn_fail_commit_memory(addr, size, exec, err);
2806 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2807 }
2808 }
2810 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2811 #ifndef MAP_HUGETLB
2812 #define MAP_HUGETLB 0x40000
2813 #endif
2815 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2816 #ifndef MADV_HUGEPAGE
2817 #define MADV_HUGEPAGE 14
2818 #endif
2820 int os::Linux::commit_memory_impl(char* addr, size_t size,
2821 size_t alignment_hint, bool exec) {
2822 int err = os::Linux::commit_memory_impl(addr, size, exec);
2823 if (err == 0) {
2824 realign_memory(addr, size, alignment_hint);
2825 }
2826 return err;
2827 }
2829 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2830 bool exec) {
2831 return os::Linux::commit_memory_impl(addr, size, alignment_hint, exec) == 0;
2832 }
2834 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2835 size_t alignment_hint, bool exec,
2836 const char* mesg) {
2837 assert(mesg != NULL, "mesg must be specified");
2838 int err = os::Linux::commit_memory_impl(addr, size, alignment_hint, exec);
2839 if (err != 0) {
2840 // the caller wants all commit errors to exit with the specified mesg:
2841 warn_fail_commit_memory(addr, size, alignment_hint, exec, err);
2842 vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2843 }
2844 }
2846 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2847 if (UseTransparentHugePages && alignment_hint > (size_t)vm_page_size()) {
2848 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2849 // be supported or the memory may already be backed by huge pages.
2850 ::madvise(addr, bytes, MADV_HUGEPAGE);
2851 }
2852 }
2854 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2855 // This method works by doing an mmap over an existing mmaping and effectively discarding
2856 // the existing pages. However it won't work for SHM-based large pages that cannot be
2857 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2858 // small pages on top of the SHM segment. This method always works for small pages, so we
2859 // allow that in any case.
2860 if (alignment_hint <= (size_t)os::vm_page_size() || can_commit_large_page_memory()) {
2861 commit_memory(addr, bytes, alignment_hint, !ExecMem);
2862 }
2863 }
2865 void os::numa_make_global(char *addr, size_t bytes) {
2866 Linux::numa_interleave_memory(addr, bytes);
2867 }
2869 // Define for numa_set_bind_policy(int). Setting the argument to 0 will set the
2870 // bind policy to MPOL_PREFERRED for the current thread.
2871 #define USE_MPOL_PREFERRED 0
2873 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2874 // To make NUMA and large pages more robust when both enabled, we need to ease
2875 // the requirements on where the memory should be allocated. MPOL_BIND is the
2876 // default policy and it will force memory to be allocated on the specified
2877 // node. Changing this to MPOL_PREFERRED will prefer to allocate the memory on
2878 // the specified node, but will not force it. Using this policy will prevent
2879 // getting SIGBUS when trying to allocate large pages on NUMA nodes with no
2880 // free large pages.
2881 Linux::numa_set_bind_policy(USE_MPOL_PREFERRED);
2882 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2883 }
2885 bool os::numa_topology_changed() { return false; }
2887 size_t os::numa_get_groups_num() {
2888 // Return just the number of nodes in which it's possible to allocate memory
2889 // (in numa terminology, configured nodes).
2890 return Linux::numa_num_configured_nodes();
2891 }
2893 int os::numa_get_group_id() {
2894 int cpu_id = Linux::sched_getcpu();
2895 if (cpu_id != -1) {
2896 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2897 if (lgrp_id != -1) {
2898 return lgrp_id;
2899 }
2900 }
2901 return 0;
2902 }
2904 int os::Linux::get_existing_num_nodes() {
2905 size_t node;
2906 size_t highest_node_number = Linux::numa_max_node();
2907 int num_nodes = 0;
2909 // Get the total number of nodes in the system including nodes without memory.
2910 for (node = 0; node <= highest_node_number; node++) {
2911 if (isnode_in_existing_nodes(node)) {
2912 num_nodes++;
2913 }
2914 }
2915 return num_nodes;
2916 }
2918 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2919 size_t highest_node_number = Linux::numa_max_node();
2920 size_t i = 0;
2922 // Map all node ids in which is possible to allocate memory. Also nodes are
2923 // not always consecutively available, i.e. available from 0 to the highest
2924 // node number.
2925 for (size_t node = 0; node <= highest_node_number; node++) {
2926 if (Linux::isnode_in_configured_nodes(node)) {
2927 ids[i++] = node;
2928 }
2929 }
2930 return i;
2931 }
2933 bool os::get_page_info(char *start, page_info* info) {
2934 return false;
2935 }
2937 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2938 return end;
2939 }
2942 int os::Linux::sched_getcpu_syscall(void) {
2943 unsigned int cpu = 0;
2944 int retval = -1;
2946 #if defined(IA32)
2947 # ifndef SYS_getcpu
2948 # define SYS_getcpu 318
2949 # endif
2950 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2951 #elif defined(AMD64)
2952 // Unfortunately we have to bring all these macros here from vsyscall.h
2953 // to be able to compile on old linuxes.
2954 # define __NR_vgetcpu 2
2955 # define VSYSCALL_START (-10UL << 20)
2956 # define VSYSCALL_SIZE 1024
2957 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2958 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2959 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2960 retval = vgetcpu(&cpu, NULL, NULL);
2961 #endif
2963 return (retval == -1) ? retval : cpu;
2964 }
2966 // Something to do with the numa-aware allocator needs these symbols
2967 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2968 extern "C" JNIEXPORT void numa_error(char *where) { }
2969 extern "C" JNIEXPORT int fork1() { return fork(); }
2971 // Handle request to load libnuma symbol version 1.1 (API v1). If it fails
2972 // load symbol from base version instead.
2973 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2974 void *f = dlvsym(handle, name, "libnuma_1.1");
2975 if (f == NULL) {
2976 f = dlsym(handle, name);
2977 }
2978 return f;
2979 }
2981 // Handle request to load libnuma symbol version 1.2 (API v2) only.
2982 // Return NULL if the symbol is not defined in this particular version.
2983 void* os::Linux::libnuma_v2_dlsym(void* handle, const char* name) {
2984 return dlvsym(handle, name, "libnuma_1.2");
2985 }
2987 bool os::Linux::libnuma_init() {
2988 // sched_getcpu() should be in libc.
2989 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2990 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2992 // If it's not, try a direct syscall.
2993 if (sched_getcpu() == -1)
2994 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2996 if (sched_getcpu() != -1) { // Does it work?
2997 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2998 if (handle != NULL) {
2999 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
3000 libnuma_dlsym(handle, "numa_node_to_cpus")));
3001 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
3002 libnuma_dlsym(handle, "numa_max_node")));
3003 set_numa_num_configured_nodes(CAST_TO_FN_PTR(numa_num_configured_nodes_func_t,
3004 libnuma_dlsym(handle, "numa_num_configured_nodes")));
3005 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
3006 libnuma_dlsym(handle, "numa_available")));
3007 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
3008 libnuma_dlsym(handle, "numa_tonode_memory")));
3009 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
3010 libnuma_dlsym(handle, "numa_interleave_memory")));
3011 set_numa_interleave_memory_v2(CAST_TO_FN_PTR(numa_interleave_memory_v2_func_t,
3012 libnuma_v2_dlsym(handle, "numa_interleave_memory")));
3013 set_numa_set_bind_policy(CAST_TO_FN_PTR(numa_set_bind_policy_func_t,
3014 libnuma_dlsym(handle, "numa_set_bind_policy")));
3015 set_numa_bitmask_isbitset(CAST_TO_FN_PTR(numa_bitmask_isbitset_func_t,
3016 libnuma_dlsym(handle, "numa_bitmask_isbitset")));
3017 set_numa_distance(CAST_TO_FN_PTR(numa_distance_func_t,
3018 libnuma_dlsym(handle, "numa_distance")));
3020 if (numa_available() != -1) {
3021 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
3022 set_numa_all_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_all_nodes_ptr"));
3023 set_numa_nodes_ptr((struct bitmask **)libnuma_dlsym(handle, "numa_nodes_ptr"));
3024 // Create an index -> node mapping, since nodes are not always consecutive
3025 _nindex_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3026 rebuild_nindex_to_node_map();
3027 // Create a cpu -> node mapping
3028 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
3029 rebuild_cpu_to_node_map();
3030 return true;
3031 }
3032 }
3033 }
3034 return false;
3035 }
3037 void os::Linux::rebuild_nindex_to_node_map() {
3038 int highest_node_number = Linux::numa_max_node();
3040 nindex_to_node()->clear();
3041 for (int node = 0; node <= highest_node_number; node++) {
3042 if (Linux::isnode_in_existing_nodes(node)) {
3043 nindex_to_node()->append(node);
3044 }
3045 }
3046 }
3048 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
3049 // The table is later used in get_node_by_cpu().
3050 void os::Linux::rebuild_cpu_to_node_map() {
3051 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
3052 // in libnuma (possible values are starting from 16,
3053 // and continuing up with every other power of 2, but less
3054 // than the maximum number of CPUs supported by kernel), and
3055 // is a subject to change (in libnuma version 2 the requirements
3056 // are more reasonable) we'll just hardcode the number they use
3057 // in the library.
3058 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
3060 size_t cpu_num = processor_count();
3061 size_t cpu_map_size = NCPUS / BitsPerCLong;
3062 size_t cpu_map_valid_size =
3063 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
3065 cpu_to_node()->clear();
3066 cpu_to_node()->at_grow(cpu_num - 1);
3068 size_t node_num = get_existing_num_nodes();
3070 int distance = 0;
3071 int closest_distance = INT_MAX;
3072 int closest_node = 0;
3073 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
3074 for (size_t i = 0; i < node_num; i++) {
3075 // Check if node is configured (not a memory-less node). If it is not, find
3076 // the closest configured node.
3077 if (!isnode_in_configured_nodes(nindex_to_node()->at(i))) {
3078 closest_distance = INT_MAX;
3079 // Check distance from all remaining nodes in the system. Ignore distance
3080 // from itself and from another non-configured node.
3081 for (size_t m = 0; m < node_num; m++) {
3082 if (m != i && isnode_in_configured_nodes(nindex_to_node()->at(m))) {
3083 distance = numa_distance(nindex_to_node()->at(i), nindex_to_node()->at(m));
3084 // If a closest node is found, update. There is always at least one
3085 // configured node in the system so there is always at least one node
3086 // close.
3087 if (distance != 0 && distance < closest_distance) {
3088 closest_distance = distance;
3089 closest_node = nindex_to_node()->at(m);
3090 }
3091 }
3092 }
3093 } else {
3094 // Current node is already a configured node.
3095 closest_node = nindex_to_node()->at(i);
3096 }
3098 // Get cpus from the original node and map them to the closest node. If node
3099 // is a configured node (not a memory-less node), then original node and
3100 // closest node are the same.
3101 if (numa_node_to_cpus(nindex_to_node()->at(i), cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
3102 for (size_t j = 0; j < cpu_map_valid_size; j++) {
3103 if (cpu_map[j] != 0) {
3104 for (size_t k = 0; k < BitsPerCLong; k++) {
3105 if (cpu_map[j] & (1UL << k)) {
3106 cpu_to_node()->at_put(j * BitsPerCLong + k, closest_node);
3107 }
3108 }
3109 }
3110 }
3111 }
3112 }
3113 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
3114 }
3116 int os::Linux::get_node_by_cpu(int cpu_id) {
3117 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
3118 return cpu_to_node()->at(cpu_id);
3119 }
3120 return -1;
3121 }
3123 GrowableArray<int>* os::Linux::_cpu_to_node;
3124 GrowableArray<int>* os::Linux::_nindex_to_node;
3125 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
3126 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
3127 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
3128 os::Linux::numa_num_configured_nodes_func_t os::Linux::_numa_num_configured_nodes;
3129 os::Linux::numa_available_func_t os::Linux::_numa_available;
3130 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
3131 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
3132 os::Linux::numa_interleave_memory_v2_func_t os::Linux::_numa_interleave_memory_v2;
3133 os::Linux::numa_set_bind_policy_func_t os::Linux::_numa_set_bind_policy;
3134 os::Linux::numa_bitmask_isbitset_func_t os::Linux::_numa_bitmask_isbitset;
3135 os::Linux::numa_distance_func_t os::Linux::_numa_distance;
3136 unsigned long* os::Linux::_numa_all_nodes;
3137 struct bitmask* os::Linux::_numa_all_nodes_ptr;
3138 struct bitmask* os::Linux::_numa_nodes_ptr;
3140 bool os::pd_uncommit_memory(char* addr, size_t size) {
3141 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
3142 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
3143 return res != (uintptr_t) MAP_FAILED;
3144 }
3146 static
3147 address get_stack_commited_bottom(address bottom, size_t size) {
3148 address nbot = bottom;
3149 address ntop = bottom + size;
3151 size_t page_sz = os::vm_page_size();
3152 unsigned pages = size / page_sz;
3154 unsigned char vec[1];
3155 unsigned imin = 1, imax = pages + 1, imid;
3156 int mincore_return_value = 0;
3158 assert(imin <= imax, "Unexpected page size");
3160 while (imin < imax) {
3161 imid = (imax + imin) / 2;
3162 nbot = ntop - (imid * page_sz);
3164 // Use a trick with mincore to check whether the page is mapped or not.
3165 // mincore sets vec to 1 if page resides in memory and to 0 if page
3166 // is swapped output but if page we are asking for is unmapped
3167 // it returns -1,ENOMEM
3168 mincore_return_value = mincore(nbot, page_sz, vec);
3170 if (mincore_return_value == -1) {
3171 // Page is not mapped go up
3172 // to find first mapped page
3173 if (errno != EAGAIN) {
3174 assert(errno == ENOMEM, "Unexpected mincore errno");
3175 imax = imid;
3176 }
3177 } else {
3178 // Page is mapped go down
3179 // to find first not mapped page
3180 imin = imid + 1;
3181 }
3182 }
3184 nbot = nbot + page_sz;
3186 // Adjust stack bottom one page up if last checked page is not mapped
3187 if (mincore_return_value == -1) {
3188 nbot = nbot + page_sz;
3189 }
3191 return nbot;
3192 }
3195 // Linux uses a growable mapping for the stack, and if the mapping for
3196 // the stack guard pages is not removed when we detach a thread the
3197 // stack cannot grow beyond the pages where the stack guard was
3198 // mapped. If at some point later in the process the stack expands to
3199 // that point, the Linux kernel cannot expand the stack any further
3200 // because the guard pages are in the way, and a segfault occurs.
3201 //
3202 // However, it's essential not to split the stack region by unmapping
3203 // a region (leaving a hole) that's already part of the stack mapping,
3204 // so if the stack mapping has already grown beyond the guard pages at
3205 // the time we create them, we have to truncate the stack mapping.
3206 // So, we need to know the extent of the stack mapping when
3207 // create_stack_guard_pages() is called.
3209 // We only need this for stacks that are growable: at the time of
3210 // writing thread stacks don't use growable mappings (i.e. those
3211 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
3212 // only applies to the main thread.
3214 // If the (growable) stack mapping already extends beyond the point
3215 // where we're going to put our guard pages, truncate the mapping at
3216 // that point by munmap()ping it. This ensures that when we later
3217 // munmap() the guard pages we don't leave a hole in the stack
3218 // mapping. This only affects the main/primordial thread
3220 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
3222 if (os::is_primordial_thread()) {
3223 // As we manually grow stack up to bottom inside create_attached_thread(),
3224 // it's likely that os::Linux::initial_thread_stack_bottom is mapped and
3225 // we don't need to do anything special.
3226 // Check it first, before calling heavy function.
3227 uintptr_t stack_extent = (uintptr_t) os::Linux::initial_thread_stack_bottom();
3228 unsigned char vec[1];
3230 if (mincore((address)stack_extent, os::vm_page_size(), vec) == -1) {
3231 // Fallback to slow path on all errors, including EAGAIN
3232 stack_extent = (uintptr_t) get_stack_commited_bottom(
3233 os::Linux::initial_thread_stack_bottom(),
3234 (size_t)addr - stack_extent);
3235 }
3237 if (stack_extent < (uintptr_t)addr) {
3238 ::munmap((void*)stack_extent, (uintptr_t)(addr - stack_extent));
3239 }
3240 }
3242 return os::commit_memory(addr, size, !ExecMem);
3243 }
3245 // If this is a growable mapping, remove the guard pages entirely by
3246 // munmap()ping them. If not, just call uncommit_memory(). This only
3247 // affects the main/primordial thread, but guard against future OS changes.
3248 // It's safe to always unmap guard pages for primordial thread because we
3249 // always place it right after end of the mapped region.
3251 bool os::remove_stack_guard_pages(char* addr, size_t size) {
3252 uintptr_t stack_extent, stack_base;
3254 if (os::is_primordial_thread()) {
3255 return ::munmap(addr, size) == 0;
3256 }
3258 return os::uncommit_memory(addr, size);
3259 }
3261 static address _highest_vm_reserved_address = NULL;
3263 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
3264 // at 'requested_addr'. If there are existing memory mappings at the same
3265 // location, however, they will be overwritten. If 'fixed' is false,
3266 // 'requested_addr' is only treated as a hint, the return value may or
3267 // may not start from the requested address. Unlike Linux mmap(), this
3268 // function returns NULL to indicate failure.
3269 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
3270 char * addr;
3271 int flags;
3273 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
3274 if (fixed) {
3275 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
3276 flags |= MAP_FIXED;
3277 }
3279 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
3280 // touch an uncommitted page. Otherwise, the read/write might
3281 // succeed if we have enough swap space to back the physical page.
3282 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
3283 flags, -1, 0);
3285 if (addr != MAP_FAILED) {
3286 // anon_mmap() should only get called during VM initialization,
3287 // don't need lock (actually we can skip locking even it can be called
3288 // from multiple threads, because _highest_vm_reserved_address is just a
3289 // hint about the upper limit of non-stack memory regions.)
3290 if ((address)addr + bytes > _highest_vm_reserved_address) {
3291 _highest_vm_reserved_address = (address)addr + bytes;
3292 }
3293 }
3295 return addr == MAP_FAILED ? NULL : addr;
3296 }
3298 // Allocate (using mmap, NO_RESERVE, with small pages) at either a given request address
3299 // (req_addr != NULL) or with a given alignment.
3300 // - bytes shall be a multiple of alignment.
3301 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3302 // - alignment sets the alignment at which memory shall be allocated.
3303 // It must be a multiple of allocation granularity.
3304 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3305 // req_addr or NULL.
3306 static char* anon_mmap_aligned(size_t bytes, size_t alignment, char* req_addr) {
3308 size_t extra_size = bytes;
3309 if (req_addr == NULL && alignment > 0) {
3310 extra_size += alignment;
3311 }
3313 char* start = (char*) ::mmap(req_addr, extra_size, PROT_NONE,
3314 MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
3315 -1, 0);
3316 if (start == MAP_FAILED) {
3317 start = NULL;
3318 } else {
3319 if (req_addr != NULL) {
3320 if (start != req_addr) {
3321 ::munmap(start, extra_size);
3322 start = NULL;
3323 }
3324 } else {
3325 char* const start_aligned = (char*) align_ptr_up(start, alignment);
3326 char* const end_aligned = start_aligned + bytes;
3327 char* const end = start + extra_size;
3328 if (start_aligned > start) {
3329 ::munmap(start, start_aligned - start);
3330 }
3331 if (end_aligned < end) {
3332 ::munmap(end_aligned, end - end_aligned);
3333 }
3334 start = start_aligned;
3335 }
3336 }
3337 return start;
3338 }
3340 // Don't update _highest_vm_reserved_address, because there might be memory
3341 // regions above addr + size. If so, releasing a memory region only creates
3342 // a hole in the address space, it doesn't help prevent heap-stack collision.
3343 //
3344 static int anon_munmap(char * addr, size_t size) {
3345 return ::munmap(addr, size) == 0;
3346 }
3348 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
3349 size_t alignment_hint) {
3350 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
3351 }
3353 bool os::pd_release_memory(char* addr, size_t size) {
3354 return anon_munmap(addr, size);
3355 }
3357 static address highest_vm_reserved_address() {
3358 return _highest_vm_reserved_address;
3359 }
3361 static bool linux_mprotect(char* addr, size_t size, int prot) {
3362 // Linux wants the mprotect address argument to be page aligned.
3363 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
3365 // According to SUSv3, mprotect() should only be used with mappings
3366 // established by mmap(), and mmap() always maps whole pages. Unaligned
3367 // 'addr' likely indicates problem in the VM (e.g. trying to change
3368 // protection of malloc'ed or statically allocated memory). Check the
3369 // caller if you hit this assert.
3370 assert(addr == bottom, "sanity check");
3372 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
3373 return ::mprotect(bottom, size, prot) == 0;
3374 }
3376 // Set protections specified
3377 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
3378 bool is_committed) {
3379 unsigned int p = 0;
3380 switch (prot) {
3381 case MEM_PROT_NONE: p = PROT_NONE; break;
3382 case MEM_PROT_READ: p = PROT_READ; break;
3383 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
3384 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
3385 default:
3386 ShouldNotReachHere();
3387 }
3388 // is_committed is unused.
3389 return linux_mprotect(addr, bytes, p);
3390 }
3392 bool os::guard_memory(char* addr, size_t size) {
3393 return linux_mprotect(addr, size, PROT_NONE);
3394 }
3396 bool os::unguard_memory(char* addr, size_t size) {
3397 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
3398 }
3400 bool os::Linux::transparent_huge_pages_sanity_check(bool warn, size_t page_size) {
3401 bool result = false;
3402 void *p = mmap(NULL, page_size * 2, PROT_READ|PROT_WRITE,
3403 MAP_ANONYMOUS|MAP_PRIVATE,
3404 -1, 0);
3405 if (p != MAP_FAILED) {
3406 void *aligned_p = align_ptr_up(p, page_size);
3408 result = madvise(aligned_p, page_size, MADV_HUGEPAGE) == 0;
3410 munmap(p, page_size * 2);
3411 }
3413 if (warn && !result) {
3414 warning("TransparentHugePages is not supported by the operating system.");
3415 }
3417 return result;
3418 }
3420 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
3421 bool result = false;
3422 void *p = mmap(NULL, page_size, PROT_READ|PROT_WRITE,
3423 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
3424 -1, 0);
3426 if (p != MAP_FAILED) {
3427 // We don't know if this really is a huge page or not.
3428 FILE *fp = fopen("/proc/self/maps", "r");
3429 if (fp) {
3430 while (!feof(fp)) {
3431 char chars[257];
3432 long x = 0;
3433 if (fgets(chars, sizeof(chars), fp)) {
3434 if (sscanf(chars, "%lx-%*x", &x) == 1
3435 && x == (long)p) {
3436 if (strstr (chars, "hugepage")) {
3437 result = true;
3438 break;
3439 }
3440 }
3441 }
3442 }
3443 fclose(fp);
3444 }
3445 munmap(p, page_size);
3446 }
3448 if (warn && !result) {
3449 warning("HugeTLBFS is not supported by the operating system.");
3450 }
3452 return result;
3453 }
3455 /*
3456 * Set the coredump_filter bits to include largepages in core dump (bit 6)
3457 *
3458 * From the coredump_filter documentation:
3459 *
3460 * - (bit 0) anonymous private memory
3461 * - (bit 1) anonymous shared memory
3462 * - (bit 2) file-backed private memory
3463 * - (bit 3) file-backed shared memory
3464 * - (bit 4) ELF header pages in file-backed private memory areas (it is
3465 * effective only if the bit 2 is cleared)
3466 * - (bit 5) hugetlb private memory
3467 * - (bit 6) hugetlb shared memory
3468 */
3469 static void set_coredump_filter(void) {
3470 FILE *f;
3471 long cdm;
3473 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
3474 return;
3475 }
3477 if (fscanf(f, "%lx", &cdm) != 1) {
3478 fclose(f);
3479 return;
3480 }
3482 rewind(f);
3484 if ((cdm & LARGEPAGES_BIT) == 0) {
3485 cdm |= LARGEPAGES_BIT;
3486 fprintf(f, "%#lx", cdm);
3487 }
3489 fclose(f);
3490 }
3492 // Large page support
3494 static size_t _large_page_size = 0;
3496 size_t os::Linux::find_large_page_size() {
3497 size_t large_page_size = 0;
3499 // large_page_size on Linux is used to round up heap size. x86 uses either
3500 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
3501 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
3502 // page as large as 256M.
3503 //
3504 // Here we try to figure out page size by parsing /proc/meminfo and looking
3505 // for a line with the following format:
3506 // Hugepagesize: 2048 kB
3507 //
3508 // If we can't determine the value (e.g. /proc is not mounted, or the text
3509 // format has been changed), we'll use the largest page size supported by
3510 // the processor.
3512 #ifndef ZERO
3513 large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3514 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3515 #endif // ZERO
3517 FILE *fp = fopen("/proc/meminfo", "r");
3518 if (fp) {
3519 while (!feof(fp)) {
3520 int x = 0;
3521 char buf[16];
3522 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3523 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3524 large_page_size = x * K;
3525 break;
3526 }
3527 } else {
3528 // skip to next line
3529 for (;;) {
3530 int ch = fgetc(fp);
3531 if (ch == EOF || ch == (int)'\n') break;
3532 }
3533 }
3534 }
3535 fclose(fp);
3536 }
3538 if (!FLAG_IS_DEFAULT(LargePageSizeInBytes) && LargePageSizeInBytes != large_page_size) {
3539 warning("Setting LargePageSizeInBytes has no effect on this OS. Large page size is "
3540 SIZE_FORMAT "%s.", byte_size_in_proper_unit(large_page_size),
3541 proper_unit_for_byte_size(large_page_size));
3542 }
3544 return large_page_size;
3545 }
3547 size_t os::Linux::setup_large_page_size() {
3548 _large_page_size = Linux::find_large_page_size();
3549 const size_t default_page_size = (size_t)Linux::page_size();
3550 if (_large_page_size > default_page_size) {
3551 _page_sizes[0] = _large_page_size;
3552 _page_sizes[1] = default_page_size;
3553 _page_sizes[2] = 0;
3554 }
3556 return _large_page_size;
3557 }
3559 bool os::Linux::setup_large_page_type(size_t page_size) {
3560 if (FLAG_IS_DEFAULT(UseHugeTLBFS) &&
3561 FLAG_IS_DEFAULT(UseSHM) &&
3562 FLAG_IS_DEFAULT(UseTransparentHugePages)) {
3564 // The type of large pages has not been specified by the user.
3566 // Try UseHugeTLBFS and then UseSHM.
3567 UseHugeTLBFS = UseSHM = true;
3569 // Don't try UseTransparentHugePages since there are known
3570 // performance issues with it turned on. This might change in the future.
3571 UseTransparentHugePages = false;
3572 }
3574 if (UseTransparentHugePages) {
3575 bool warn_on_failure = !FLAG_IS_DEFAULT(UseTransparentHugePages);
3576 if (transparent_huge_pages_sanity_check(warn_on_failure, page_size)) {
3577 UseHugeTLBFS = false;
3578 UseSHM = false;
3579 return true;
3580 }
3581 UseTransparentHugePages = false;
3582 }
3584 if (UseHugeTLBFS) {
3585 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3586 if (hugetlbfs_sanity_check(warn_on_failure, page_size)) {
3587 UseSHM = false;
3588 return true;
3589 }
3590 UseHugeTLBFS = false;
3591 }
3593 return UseSHM;
3594 }
3596 void os::large_page_init() {
3597 if (!UseLargePages &&
3598 !UseTransparentHugePages &&
3599 !UseHugeTLBFS &&
3600 !UseSHM) {
3601 // Not using large pages.
3602 return;
3603 }
3605 if (!FLAG_IS_DEFAULT(UseLargePages) && !UseLargePages) {
3606 // The user explicitly turned off large pages.
3607 // Ignore the rest of the large pages flags.
3608 UseTransparentHugePages = false;
3609 UseHugeTLBFS = false;
3610 UseSHM = false;
3611 return;
3612 }
3614 size_t large_page_size = Linux::setup_large_page_size();
3615 UseLargePages = Linux::setup_large_page_type(large_page_size);
3617 set_coredump_filter();
3618 }
3620 #ifndef SHM_HUGETLB
3621 #define SHM_HUGETLB 04000
3622 #endif
3624 #define shm_warning_format(format, ...) \
3625 do { \
3626 if (UseLargePages && \
3627 (!FLAG_IS_DEFAULT(UseLargePages) || \
3628 !FLAG_IS_DEFAULT(UseSHM) || \
3629 !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { \
3630 warning(format, __VA_ARGS__); \
3631 } \
3632 } while (0)
3634 #define shm_warning(str) shm_warning_format("%s", str)
3636 #define shm_warning_with_errno(str) \
3637 do { \
3638 int err = errno; \
3639 shm_warning_format(str " (error = %d)", err); \
3640 } while (0)
3642 static char* shmat_with_alignment(int shmid, size_t bytes, size_t alignment) {
3643 assert(is_size_aligned(bytes, alignment), "Must be divisible by the alignment");
3645 if (!is_size_aligned(alignment, SHMLBA)) {
3646 assert(false, "Code below assumes that alignment is at least SHMLBA aligned");
3647 return NULL;
3648 }
3650 // To ensure that we get 'alignment' aligned memory from shmat,
3651 // we pre-reserve aligned virtual memory and then attach to that.
3653 char* pre_reserved_addr = anon_mmap_aligned(bytes, alignment, NULL);
3654 if (pre_reserved_addr == NULL) {
3655 // Couldn't pre-reserve aligned memory.
3656 shm_warning("Failed to pre-reserve aligned memory for shmat.");
3657 return NULL;
3658 }
3660 // SHM_REMAP is needed to allow shmat to map over an existing mapping.
3661 char* addr = (char*)shmat(shmid, pre_reserved_addr, SHM_REMAP);
3663 if ((intptr_t)addr == -1) {
3664 int err = errno;
3665 shm_warning_with_errno("Failed to attach shared memory.");
3667 assert(err != EACCES, "Unexpected error");
3668 assert(err != EIDRM, "Unexpected error");
3669 assert(err != EINVAL, "Unexpected error");
3671 // Since we don't know if the kernel unmapped the pre-reserved memory area
3672 // we can't unmap it, since that would potentially unmap memory that was
3673 // mapped from other threads.
3674 return NULL;
3675 }
3677 return addr;
3678 }
3680 static char* shmat_at_address(int shmid, char* req_addr) {
3681 if (!is_ptr_aligned(req_addr, SHMLBA)) {
3682 assert(false, "Requested address needs to be SHMLBA aligned");
3683 return NULL;
3684 }
3686 char* addr = (char*)shmat(shmid, req_addr, 0);
3688 if ((intptr_t)addr == -1) {
3689 shm_warning_with_errno("Failed to attach shared memory.");
3690 return NULL;
3691 }
3693 return addr;
3694 }
3696 static char* shmat_large_pages(int shmid, size_t bytes, size_t alignment, char* req_addr) {
3697 // If a req_addr has been provided, we assume that the caller has already aligned the address.
3698 if (req_addr != NULL) {
3699 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Must be divisible by the large page size");
3700 assert(is_ptr_aligned(req_addr, alignment), "Must be divisible by given alignment");
3701 return shmat_at_address(shmid, req_addr);
3702 }
3704 // Since shmid has been setup with SHM_HUGETLB, shmat will automatically
3705 // return large page size aligned memory addresses when req_addr == NULL.
3706 // However, if the alignment is larger than the large page size, we have
3707 // to manually ensure that the memory returned is 'alignment' aligned.
3708 if (alignment > os::large_page_size()) {
3709 assert(is_size_aligned(alignment, os::large_page_size()), "Must be divisible by the large page size");
3710 return shmat_with_alignment(shmid, bytes, alignment);
3711 } else {
3712 return shmat_at_address(shmid, NULL);
3713 }
3714 }
3716 char* os::Linux::reserve_memory_special_shm(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3717 // "exec" is passed in but not used. Creating the shared image for
3718 // the code cache doesn't have an SHM_X executable permission to check.
3719 assert(UseLargePages && UseSHM, "only for SHM large pages");
3720 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3721 assert(is_ptr_aligned(req_addr, alignment), "Unaligned address");
3723 if (!is_size_aligned(bytes, os::large_page_size())) {
3724 return NULL; // Fallback to small pages.
3725 }
3727 // Create a large shared memory region to attach to based on size.
3728 // Currently, size is the total size of the heap.
3729 int shmid = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3730 if (shmid == -1) {
3731 // Possible reasons for shmget failure:
3732 // 1. shmmax is too small for Java heap.
3733 // > check shmmax value: cat /proc/sys/kernel/shmmax
3734 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3735 // 2. not enough large page memory.
3736 // > check available large pages: cat /proc/meminfo
3737 // > increase amount of large pages:
3738 // echo new_value > /proc/sys/vm/nr_hugepages
3739 // Note 1: different Linux may use different name for this property,
3740 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3741 // Note 2: it's possible there's enough physical memory available but
3742 // they are so fragmented after a long run that they can't
3743 // coalesce into large pages. Try to reserve large pages when
3744 // the system is still "fresh".
3745 shm_warning_with_errno("Failed to reserve shared memory.");
3746 return NULL;
3747 }
3749 // Attach to the region.
3750 char* addr = shmat_large_pages(shmid, bytes, alignment, req_addr);
3752 // Remove shmid. If shmat() is successful, the actual shared memory segment
3753 // will be deleted when it's detached by shmdt() or when the process
3754 // terminates. If shmat() is not successful this will remove the shared
3755 // segment immediately.
3756 shmctl(shmid, IPC_RMID, NULL);
3758 return addr;
3759 }
3761 static void warn_on_large_pages_failure(char* req_addr, size_t bytes, int error) {
3762 assert(error == ENOMEM, "Only expect to fail if no memory is available");
3764 bool warn_on_failure = UseLargePages &&
3765 (!FLAG_IS_DEFAULT(UseLargePages) ||
3766 !FLAG_IS_DEFAULT(UseHugeTLBFS) ||
3767 !FLAG_IS_DEFAULT(LargePageSizeInBytes));
3769 if (warn_on_failure) {
3770 char msg[128];
3771 jio_snprintf(msg, sizeof(msg), "Failed to reserve large pages memory req_addr: "
3772 PTR_FORMAT " bytes: " SIZE_FORMAT " (errno = %d).", req_addr, bytes, error);
3773 warning("%s", msg);
3774 }
3775 }
3777 char* os::Linux::reserve_memory_special_huge_tlbfs_only(size_t bytes, char* req_addr, bool exec) {
3778 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3779 assert(is_size_aligned(bytes, os::large_page_size()), "Unaligned size");
3780 assert(is_ptr_aligned(req_addr, os::large_page_size()), "Unaligned address");
3782 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3783 char* addr = (char*)::mmap(req_addr, bytes, prot,
3784 MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB,
3785 -1, 0);
3787 if (addr == MAP_FAILED) {
3788 warn_on_large_pages_failure(req_addr, bytes, errno);
3789 return NULL;
3790 }
3792 assert(is_ptr_aligned(addr, os::large_page_size()), "Must be");
3794 return addr;
3795 }
3797 // Reserve memory using mmap(MAP_HUGETLB).
3798 // - bytes shall be a multiple of alignment.
3799 // - req_addr can be NULL. If not NULL, it must be a multiple of alignment.
3800 // - alignment sets the alignment at which memory shall be allocated.
3801 // It must be a multiple of allocation granularity.
3802 // Returns address of memory or NULL. If req_addr was not NULL, will only return
3803 // req_addr or NULL.
3804 char* os::Linux::reserve_memory_special_huge_tlbfs_mixed(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3805 size_t large_page_size = os::large_page_size();
3806 assert(bytes >= large_page_size, "Shouldn't allocate large pages for small sizes");
3808 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3809 assert(is_size_aligned(bytes, alignment), "Must be");
3811 // First reserve - but not commit - the address range in small pages.
3812 char* const start = anon_mmap_aligned(bytes, alignment, req_addr);
3814 if (start == NULL) {
3815 return NULL;
3816 }
3818 assert(is_ptr_aligned(start, alignment), "Must be");
3820 char* end = start + bytes;
3822 // Find the regions of the allocated chunk that can be promoted to large pages.
3823 char* lp_start = (char*)align_ptr_up(start, large_page_size);
3824 char* lp_end = (char*)align_ptr_down(end, large_page_size);
3826 size_t lp_bytes = lp_end - lp_start;
3828 assert(is_size_aligned(lp_bytes, large_page_size), "Must be");
3830 if (lp_bytes == 0) {
3831 // The mapped region doesn't even span the start and the end of a large page.
3832 // Fall back to allocate a non-special area.
3833 ::munmap(start, end - start);
3834 return NULL;
3835 }
3837 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
3839 void* result;
3841 // Commit small-paged leading area.
3842 if (start != lp_start) {
3843 result = ::mmap(start, lp_start - start, prot,
3844 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3845 -1, 0);
3846 if (result == MAP_FAILED) {
3847 ::munmap(lp_start, end - lp_start);
3848 return NULL;
3849 }
3850 }
3852 // Commit large-paged area.
3853 result = ::mmap(lp_start, lp_bytes, prot,
3854 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED|MAP_HUGETLB,
3855 -1, 0);
3856 if (result == MAP_FAILED) {
3857 warn_on_large_pages_failure(lp_start, lp_bytes, errno);
3858 // If the mmap above fails, the large pages region will be unmapped and we
3859 // have regions before and after with small pages. Release these regions.
3860 //
3861 // | mapped | unmapped | mapped |
3862 // ^ ^ ^ ^
3863 // start lp_start lp_end end
3864 //
3865 ::munmap(start, lp_start - start);
3866 ::munmap(lp_end, end - lp_end);
3867 return NULL;
3868 }
3870 // Commit small-paged trailing area.
3871 if (lp_end != end) {
3872 result = ::mmap(lp_end, end - lp_end, prot,
3873 MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED,
3874 -1, 0);
3875 if (result == MAP_FAILED) {
3876 ::munmap(start, lp_end - start);
3877 return NULL;
3878 }
3879 }
3881 return start;
3882 }
3884 char* os::Linux::reserve_memory_special_huge_tlbfs(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3885 assert(UseLargePages && UseHugeTLBFS, "only for Huge TLBFS large pages");
3886 assert(is_ptr_aligned(req_addr, alignment), "Must be");
3887 assert(is_size_aligned(alignment, os::vm_allocation_granularity()), "Must be");
3888 assert(is_power_of_2(os::large_page_size()), "Must be");
3889 assert(bytes >= os::large_page_size(), "Shouldn't allocate large pages for small sizes");
3891 if (is_size_aligned(bytes, os::large_page_size()) && alignment <= os::large_page_size()) {
3892 return reserve_memory_special_huge_tlbfs_only(bytes, req_addr, exec);
3893 } else {
3894 return reserve_memory_special_huge_tlbfs_mixed(bytes, alignment, req_addr, exec);
3895 }
3896 }
3898 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
3899 assert(UseLargePages, "only for large pages");
3901 char* addr;
3902 if (UseSHM) {
3903 addr = os::Linux::reserve_memory_special_shm(bytes, alignment, req_addr, exec);
3904 } else {
3905 assert(UseHugeTLBFS, "must be");
3906 addr = os::Linux::reserve_memory_special_huge_tlbfs(bytes, alignment, req_addr, exec);
3907 }
3909 if (addr != NULL) {
3910 if (UseNUMAInterleaving) {
3911 numa_make_global(addr, bytes);
3912 }
3914 // The memory is committed
3915 MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
3916 }
3918 return addr;
3919 }
3921 bool os::Linux::release_memory_special_shm(char* base, size_t bytes) {
3922 // detaching the SHM segment will also delete it, see reserve_memory_special_shm()
3923 return shmdt(base) == 0;
3924 }
3926 bool os::Linux::release_memory_special_huge_tlbfs(char* base, size_t bytes) {
3927 return pd_release_memory(base, bytes);
3928 }
3930 bool os::release_memory_special(char* base, size_t bytes) {
3931 bool res;
3932 if (MemTracker::tracking_level() > NMT_minimal) {
3933 Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
3934 res = os::Linux::release_memory_special_impl(base, bytes);
3935 if (res) {
3936 tkr.record((address)base, bytes);
3937 }
3939 } else {
3940 res = os::Linux::release_memory_special_impl(base, bytes);
3941 }
3942 return res;
3943 }
3945 bool os::Linux::release_memory_special_impl(char* base, size_t bytes) {
3946 assert(UseLargePages, "only for large pages");
3947 bool res;
3949 if (UseSHM) {
3950 res = os::Linux::release_memory_special_shm(base, bytes);
3951 } else {
3952 assert(UseHugeTLBFS, "must be");
3953 res = os::Linux::release_memory_special_huge_tlbfs(base, bytes);
3954 }
3955 return res;
3956 }
3958 size_t os::large_page_size() {
3959 return _large_page_size;
3960 }
3962 // With SysV SHM the entire memory region must be allocated as shared
3963 // memory.
3964 // HugeTLBFS allows application to commit large page memory on demand.
3965 // However, when committing memory with HugeTLBFS fails, the region
3966 // that was supposed to be committed will lose the old reservation
3967 // and allow other threads to steal that memory region. Because of this
3968 // behavior we can't commit HugeTLBFS memory.
3969 bool os::can_commit_large_page_memory() {
3970 return UseTransparentHugePages;
3971 }
3973 bool os::can_execute_large_page_memory() {
3974 return UseTransparentHugePages || UseHugeTLBFS;
3975 }
3977 // Reserve memory at an arbitrary address, only if that area is
3978 // available (and not reserved for something else).
3980 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3981 const int max_tries = 10;
3982 char* base[max_tries];
3983 size_t size[max_tries];
3984 const size_t gap = 0x000000;
3986 // Assert only that the size is a multiple of the page size, since
3987 // that's all that mmap requires, and since that's all we really know
3988 // about at this low abstraction level. If we need higher alignment,
3989 // we can either pass an alignment to this method or verify alignment
3990 // in one of the methods further up the call chain. See bug 5044738.
3991 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3993 // Repeatedly allocate blocks until the block is allocated at the
3994 // right spot. Give up after max_tries. Note that reserve_memory() will
3995 // automatically update _highest_vm_reserved_address if the call is
3996 // successful. The variable tracks the highest memory address every reserved
3997 // by JVM. It is used to detect heap-stack collision if running with
3998 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3999 // space than needed, it could confuse the collision detecting code. To
4000 // solve the problem, save current _highest_vm_reserved_address and
4001 // calculate the correct value before return.
4002 address old_highest = _highest_vm_reserved_address;
4004 // Linux mmap allows caller to pass an address as hint; give it a try first,
4005 // if kernel honors the hint then we can return immediately.
4006 char * addr = anon_mmap(requested_addr, bytes, false);
4007 if (addr == requested_addr) {
4008 return requested_addr;
4009 }
4011 if (addr != NULL) {
4012 // mmap() is successful but it fails to reserve at the requested address
4013 anon_munmap(addr, bytes);
4014 }
4016 int i;
4017 for (i = 0; i < max_tries; ++i) {
4018 base[i] = reserve_memory(bytes);
4020 if (base[i] != NULL) {
4021 // Is this the block we wanted?
4022 if (base[i] == requested_addr) {
4023 size[i] = bytes;
4024 break;
4025 }
4027 // Does this overlap the block we wanted? Give back the overlapped
4028 // parts and try again.
4030 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
4031 if (top_overlap >= 0 && top_overlap < bytes) {
4032 unmap_memory(base[i], top_overlap);
4033 base[i] += top_overlap;
4034 size[i] = bytes - top_overlap;
4035 } else {
4036 size_t bottom_overlap = base[i] + bytes - requested_addr;
4037 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
4038 unmap_memory(requested_addr, bottom_overlap);
4039 size[i] = bytes - bottom_overlap;
4040 } else {
4041 size[i] = bytes;
4042 }
4043 }
4044 }
4045 }
4047 // Give back the unused reserved pieces.
4049 for (int j = 0; j < i; ++j) {
4050 if (base[j] != NULL) {
4051 unmap_memory(base[j], size[j]);
4052 }
4053 }
4055 if (i < max_tries) {
4056 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
4057 return requested_addr;
4058 } else {
4059 _highest_vm_reserved_address = old_highest;
4060 return NULL;
4061 }
4062 }
4064 size_t os::read(int fd, void *buf, unsigned int nBytes) {
4065 return ::read(fd, buf, nBytes);
4066 }
4068 size_t os::read_at(int fd, void *buf, unsigned int nBytes, jlong offset) {
4069 return ::pread(fd, buf, nBytes, offset);
4070 }
4072 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
4073 // Solaris uses poll(), linux uses park().
4074 // Poll() is likely a better choice, assuming that Thread.interrupt()
4075 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
4076 // SIGSEGV, see 4355769.
4078 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
4079 assert(thread == Thread::current(), "thread consistency check");
4081 ParkEvent * const slp = thread->_SleepEvent ;
4082 slp->reset() ;
4083 OrderAccess::fence() ;
4085 if (interruptible) {
4086 jlong prevtime = javaTimeNanos();
4088 for (;;) {
4089 if (os::is_interrupted(thread, true)) {
4090 return OS_INTRPT;
4091 }
4093 jlong newtime = javaTimeNanos();
4095 if (newtime - prevtime < 0) {
4096 // time moving backwards, should only happen if no monotonic clock
4097 // not a guarantee() because JVM should not abort on kernel/glibc bugs
4098 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
4099 } else {
4100 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
4101 }
4103 if(millis <= 0) {
4104 return OS_OK;
4105 }
4107 prevtime = newtime;
4109 {
4110 assert(thread->is_Java_thread(), "sanity check");
4111 JavaThread *jt = (JavaThread *) thread;
4112 ThreadBlockInVM tbivm(jt);
4113 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
4115 jt->set_suspend_equivalent();
4116 // cleared by handle_special_suspend_equivalent_condition() or
4117 // java_suspend_self() via check_and_wait_while_suspended()
4119 slp->park(millis);
4121 // were we externally suspended while we were waiting?
4122 jt->check_and_wait_while_suspended();
4123 }
4124 }
4125 } else {
4126 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4127 jlong prevtime = javaTimeNanos();
4129 for (;;) {
4130 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
4131 // the 1st iteration ...
4132 jlong newtime = javaTimeNanos();
4134 if (newtime - prevtime < 0) {
4135 // time moving backwards, should only happen if no monotonic clock
4136 // not a guarantee() because JVM should not abort on kernel/glibc bugs
4137 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
4138 } else {
4139 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
4140 }
4142 if(millis <= 0) break ;
4144 prevtime = newtime;
4145 slp->park(millis);
4146 }
4147 return OS_OK ;
4148 }
4149 }
4151 //
4152 // Short sleep, direct OS call.
4153 //
4154 // Note: certain versions of Linux CFS scheduler (since 2.6.23) do not guarantee
4155 // sched_yield(2) will actually give up the CPU:
4156 //
4157 // * Alone on this pariticular CPU, keeps running.
4158 // * Before the introduction of "skip_buddy" with "compat_yield" disabled
4159 // (pre 2.6.39).
4160 //
4161 // So calling this with 0 is an alternative.
4162 //
4163 void os::naked_short_sleep(jlong ms) {
4164 struct timespec req;
4166 assert(ms < 1000, "Un-interruptable sleep, short time use only");
4167 req.tv_sec = 0;
4168 if (ms > 0) {
4169 req.tv_nsec = (ms % 1000) * 1000000;
4170 }
4171 else {
4172 req.tv_nsec = 1;
4173 }
4175 nanosleep(&req, NULL);
4177 return;
4178 }
4180 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
4181 void os::infinite_sleep() {
4182 while (true) { // sleep forever ...
4183 ::sleep(100); // ... 100 seconds at a time
4184 }
4185 }
4187 // Used to convert frequent JVM_Yield() to nops
4188 bool os::dont_yield() {
4189 return DontYieldALot;
4190 }
4192 void os::yield() {
4193 sched_yield();
4194 }
4196 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
4198 void os::yield_all(int attempts) {
4199 // Yields to all threads, including threads with lower priorities
4200 // Threads on Linux are all with same priority. The Solaris style
4201 // os::yield_all() with nanosleep(1ms) is not necessary.
4202 sched_yield();
4203 }
4205 // Called from the tight loops to possibly influence time-sharing heuristics
4206 void os::loop_breaker(int attempts) {
4207 os::yield_all(attempts);
4208 }
4210 ////////////////////////////////////////////////////////////////////////////////
4211 // thread priority support
4213 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
4214 // only supports dynamic priority, static priority must be zero. For real-time
4215 // applications, Linux supports SCHED_RR which allows static priority (1-99).
4216 // However, for large multi-threaded applications, SCHED_RR is not only slower
4217 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
4218 // of 5 runs - Sep 2005).
4219 //
4220 // The following code actually changes the niceness of kernel-thread/LWP. It
4221 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
4222 // not the entire user process, and user level threads are 1:1 mapped to kernel
4223 // threads. It has always been the case, but could change in the future. For
4224 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
4225 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
4227 int os::java_to_os_priority[CriticalPriority + 1] = {
4228 19, // 0 Entry should never be used
4230 4, // 1 MinPriority
4231 3, // 2
4232 2, // 3
4234 1, // 4
4235 0, // 5 NormPriority
4236 -1, // 6
4238 -2, // 7
4239 -3, // 8
4240 -4, // 9 NearMaxPriority
4242 -5, // 10 MaxPriority
4244 -5 // 11 CriticalPriority
4245 };
4247 static int prio_init() {
4248 if (ThreadPriorityPolicy == 1) {
4249 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
4250 // if effective uid is not root. Perhaps, a more elegant way of doing
4251 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
4252 if (geteuid() != 0) {
4253 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
4254 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
4255 }
4256 ThreadPriorityPolicy = 0;
4257 }
4258 }
4259 if (UseCriticalJavaThreadPriority) {
4260 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
4261 }
4262 return 0;
4263 }
4265 OSReturn os::set_native_priority(Thread* thread, int newpri) {
4266 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
4268 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
4269 return (ret == 0) ? OS_OK : OS_ERR;
4270 }
4272 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
4273 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
4274 *priority_ptr = java_to_os_priority[NormPriority];
4275 return OS_OK;
4276 }
4278 errno = 0;
4279 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
4280 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
4281 }
4283 // Hint to the underlying OS that a task switch would not be good.
4284 // Void return because it's a hint and can fail.
4285 void os::hint_no_preempt() {}
4287 ////////////////////////////////////////////////////////////////////////////////
4288 // suspend/resume support
4290 // the low-level signal-based suspend/resume support is a remnant from the
4291 // old VM-suspension that used to be for java-suspension, safepoints etc,
4292 // within hotspot. Now there is a single use-case for this:
4293 // - calling get_thread_pc() on the VMThread by the flat-profiler task
4294 // that runs in the watcher thread.
4295 // The remaining code is greatly simplified from the more general suspension
4296 // code that used to be used.
4297 //
4298 // The protocol is quite simple:
4299 // - suspend:
4300 // - sends a signal to the target thread
4301 // - polls the suspend state of the osthread using a yield loop
4302 // - target thread signal handler (SR_handler) sets suspend state
4303 // and blocks in sigsuspend until continued
4304 // - resume:
4305 // - sets target osthread state to continue
4306 // - sends signal to end the sigsuspend loop in the SR_handler
4307 //
4308 // Note that the SR_lock plays no role in this suspend/resume protocol.
4309 //
4311 static void resume_clear_context(OSThread *osthread) {
4312 osthread->set_ucontext(NULL);
4313 osthread->set_siginfo(NULL);
4314 }
4316 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
4317 osthread->set_ucontext(context);
4318 osthread->set_siginfo(siginfo);
4319 }
4321 //
4322 // Handler function invoked when a thread's execution is suspended or
4323 // resumed. We have to be careful that only async-safe functions are
4324 // called here (Note: most pthread functions are not async safe and
4325 // should be avoided.)
4326 //
4327 // Note: sigwait() is a more natural fit than sigsuspend() from an
4328 // interface point of view, but sigwait() prevents the signal hander
4329 // from being run. libpthread would get very confused by not having
4330 // its signal handlers run and prevents sigwait()'s use with the
4331 // mutex granting granting signal.
4332 //
4333 // Currently only ever called on the VMThread and JavaThreads (PC sampling)
4334 //
4335 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
4336 // Save and restore errno to avoid confusing native code with EINTR
4337 // after sigsuspend.
4338 int old_errno = errno;
4340 Thread* thread = Thread::current();
4341 OSThread* osthread = thread->osthread();
4342 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
4344 os::SuspendResume::State current = osthread->sr.state();
4345 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
4346 suspend_save_context(osthread, siginfo, context);
4348 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
4349 os::SuspendResume::State state = osthread->sr.suspended();
4350 if (state == os::SuspendResume::SR_SUSPENDED) {
4351 sigset_t suspend_set; // signals for sigsuspend()
4353 // get current set of blocked signals and unblock resume signal
4354 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
4355 sigdelset(&suspend_set, SR_signum);
4357 sr_semaphore.signal();
4358 // wait here until we are resumed
4359 while (1) {
4360 sigsuspend(&suspend_set);
4362 os::SuspendResume::State result = osthread->sr.running();
4363 if (result == os::SuspendResume::SR_RUNNING) {
4364 sr_semaphore.signal();
4365 break;
4366 }
4367 }
4369 } else if (state == os::SuspendResume::SR_RUNNING) {
4370 // request was cancelled, continue
4371 } else {
4372 ShouldNotReachHere();
4373 }
4375 resume_clear_context(osthread);
4376 } else if (current == os::SuspendResume::SR_RUNNING) {
4377 // request was cancelled, continue
4378 } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
4379 // ignore
4380 } else {
4381 // ignore
4382 }
4384 errno = old_errno;
4385 }
4388 static int SR_initialize() {
4389 struct sigaction act;
4390 char *s;
4391 /* Get signal number to use for suspend/resume */
4392 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
4393 int sig = ::strtol(s, 0, 10);
4394 if (sig > 0 || sig < _NSIG) {
4395 SR_signum = sig;
4396 }
4397 }
4399 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
4400 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
4402 sigemptyset(&SR_sigset);
4403 sigaddset(&SR_sigset, SR_signum);
4405 /* Set up signal handler for suspend/resume */
4406 act.sa_flags = SA_RESTART|SA_SIGINFO;
4407 act.sa_handler = (void (*)(int)) SR_handler;
4409 // SR_signum is blocked by default.
4410 // 4528190 - We also need to block pthread restart signal (32 on all
4411 // supported Linux platforms). Note that LinuxThreads need to block
4412 // this signal for all threads to work properly. So we don't have
4413 // to use hard-coded signal number when setting up the mask.
4414 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
4416 if (sigaction(SR_signum, &act, 0) == -1) {
4417 return -1;
4418 }
4420 // Save signal flag
4421 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
4422 return 0;
4423 }
4425 static int sr_notify(OSThread* osthread) {
4426 int status = pthread_kill(osthread->pthread_id(), SR_signum);
4427 assert_status(status == 0, status, "pthread_kill");
4428 return status;
4429 }
4431 // "Randomly" selected value for how long we want to spin
4432 // before bailing out on suspending a thread, also how often
4433 // we send a signal to a thread we want to resume
4434 static const int RANDOMLY_LARGE_INTEGER = 1000000;
4435 static const int RANDOMLY_LARGE_INTEGER2 = 100;
4437 // returns true on success and false on error - really an error is fatal
4438 // but this seems the normal response to library errors
4439 static bool do_suspend(OSThread* osthread) {
4440 assert(osthread->sr.is_running(), "thread should be running");
4441 assert(!sr_semaphore.trywait(), "semaphore has invalid state");
4443 // mark as suspended and send signal
4444 if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
4445 // failed to switch, state wasn't running?
4446 ShouldNotReachHere();
4447 return false;
4448 }
4450 if (sr_notify(osthread) != 0) {
4451 ShouldNotReachHere();
4452 }
4454 // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
4455 while (true) {
4456 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4457 break;
4458 } else {
4459 // timeout
4460 os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
4461 if (cancelled == os::SuspendResume::SR_RUNNING) {
4462 return false;
4463 } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
4464 // make sure that we consume the signal on the semaphore as well
4465 sr_semaphore.wait();
4466 break;
4467 } else {
4468 ShouldNotReachHere();
4469 return false;
4470 }
4471 }
4472 }
4474 guarantee(osthread->sr.is_suspended(), "Must be suspended");
4475 return true;
4476 }
4478 static void do_resume(OSThread* osthread) {
4479 assert(osthread->sr.is_suspended(), "thread should be suspended");
4480 assert(!sr_semaphore.trywait(), "invalid semaphore state");
4482 if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
4483 // failed to switch to WAKEUP_REQUEST
4484 ShouldNotReachHere();
4485 return;
4486 }
4488 while (true) {
4489 if (sr_notify(osthread) == 0) {
4490 if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
4491 if (osthread->sr.is_running()) {
4492 return;
4493 }
4494 }
4495 } else {
4496 ShouldNotReachHere();
4497 }
4498 }
4500 guarantee(osthread->sr.is_running(), "Must be running!");
4501 }
4503 ////////////////////////////////////////////////////////////////////////////////
4504 // interrupt support
4506 void os::interrupt(Thread* thread) {
4507 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4508 "possibility of dangling Thread pointer");
4510 OSThread* osthread = thread->osthread();
4512 if (!osthread->interrupted()) {
4513 osthread->set_interrupted(true);
4514 // More than one thread can get here with the same value of osthread,
4515 // resulting in multiple notifications. We do, however, want the store
4516 // to interrupted() to be visible to other threads before we execute unpark().
4517 OrderAccess::fence();
4518 ParkEvent * const slp = thread->_SleepEvent ;
4519 if (slp != NULL) slp->unpark() ;
4520 }
4522 // For JSR166. Unpark even if interrupt status already was set
4523 if (thread->is_Java_thread())
4524 ((JavaThread*)thread)->parker()->unpark();
4526 ParkEvent * ev = thread->_ParkEvent ;
4527 if (ev != NULL) ev->unpark() ;
4529 }
4531 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
4532 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
4533 "possibility of dangling Thread pointer");
4535 OSThread* osthread = thread->osthread();
4537 bool interrupted = osthread->interrupted();
4539 if (interrupted && clear_interrupted) {
4540 osthread->set_interrupted(false);
4541 // consider thread->_SleepEvent->reset() ... optional optimization
4542 }
4544 return interrupted;
4545 }
4547 ///////////////////////////////////////////////////////////////////////////////////
4548 // signal handling (except suspend/resume)
4550 // This routine may be used by user applications as a "hook" to catch signals.
4551 // The user-defined signal handler must pass unrecognized signals to this
4552 // routine, and if it returns true (non-zero), then the signal handler must
4553 // return immediately. If the flag "abort_if_unrecognized" is true, then this
4554 // routine will never retun false (zero), but instead will execute a VM panic
4555 // routine kill the process.
4556 //
4557 // If this routine returns false, it is OK to call it again. This allows
4558 // the user-defined signal handler to perform checks either before or after
4559 // the VM performs its own checks. Naturally, the user code would be making
4560 // a serious error if it tried to handle an exception (such as a null check
4561 // or breakpoint) that the VM was generating for its own correct operation.
4562 //
4563 // This routine may recognize any of the following kinds of signals:
4564 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
4565 // It should be consulted by handlers for any of those signals.
4566 //
4567 // The caller of this routine must pass in the three arguments supplied
4568 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
4569 // field of the structure passed to sigaction(). This routine assumes that
4570 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
4571 //
4572 // Note that the VM will print warnings if it detects conflicting signal
4573 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
4574 //
4575 extern "C" JNIEXPORT int
4576 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
4577 void* ucontext, int abort_if_unrecognized);
4579 void signalHandler(int sig, siginfo_t* info, void* uc) {
4580 assert(info != NULL && uc != NULL, "it must be old kernel");
4581 int orig_errno = errno; // Preserve errno value over signal handler.
4582 JVM_handle_linux_signal(sig, info, uc, true);
4583 errno = orig_errno;
4584 }
4587 // This boolean allows users to forward their own non-matching signals
4588 // to JVM_handle_linux_signal, harmlessly.
4589 bool os::Linux::signal_handlers_are_installed = false;
4591 // For signal-chaining
4592 struct sigaction os::Linux::sigact[MAXSIGNUM];
4593 unsigned int os::Linux::sigs = 0;
4594 bool os::Linux::libjsig_is_loaded = false;
4595 typedef struct sigaction *(*get_signal_t)(int);
4596 get_signal_t os::Linux::get_signal_action = NULL;
4598 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
4599 struct sigaction *actp = NULL;
4601 if (libjsig_is_loaded) {
4602 // Retrieve the old signal handler from libjsig
4603 actp = (*get_signal_action)(sig);
4604 }
4605 if (actp == NULL) {
4606 // Retrieve the preinstalled signal handler from jvm
4607 actp = get_preinstalled_handler(sig);
4608 }
4610 return actp;
4611 }
4613 static bool call_chained_handler(struct sigaction *actp, int sig,
4614 siginfo_t *siginfo, void *context) {
4615 // Call the old signal handler
4616 if (actp->sa_handler == SIG_DFL) {
4617 // It's more reasonable to let jvm treat it as an unexpected exception
4618 // instead of taking the default action.
4619 return false;
4620 } else if (actp->sa_handler != SIG_IGN) {
4621 if ((actp->sa_flags & SA_NODEFER) == 0) {
4622 // automaticlly block the signal
4623 sigaddset(&(actp->sa_mask), sig);
4624 }
4626 sa_handler_t hand = NULL;
4627 sa_sigaction_t sa = NULL;
4628 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
4629 // retrieve the chained handler
4630 if (siginfo_flag_set) {
4631 sa = actp->sa_sigaction;
4632 } else {
4633 hand = actp->sa_handler;
4634 }
4636 if ((actp->sa_flags & SA_RESETHAND) != 0) {
4637 actp->sa_handler = SIG_DFL;
4638 }
4640 // try to honor the signal mask
4641 sigset_t oset;
4642 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
4644 // call into the chained handler
4645 if (siginfo_flag_set) {
4646 (*sa)(sig, siginfo, context);
4647 } else {
4648 (*hand)(sig);
4649 }
4651 // restore the signal mask
4652 pthread_sigmask(SIG_SETMASK, &oset, 0);
4653 }
4654 // Tell jvm's signal handler the signal is taken care of.
4655 return true;
4656 }
4658 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
4659 bool chained = false;
4660 // signal-chaining
4661 if (UseSignalChaining) {
4662 struct sigaction *actp = get_chained_signal_action(sig);
4663 if (actp != NULL) {
4664 chained = call_chained_handler(actp, sig, siginfo, context);
4665 }
4666 }
4667 return chained;
4668 }
4670 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
4671 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
4672 return &sigact[sig];
4673 }
4674 return NULL;
4675 }
4677 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
4678 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4679 sigact[sig] = oldAct;
4680 sigs |= (unsigned int)1 << sig;
4681 }
4683 // for diagnostic
4684 int os::Linux::sigflags[MAXSIGNUM];
4686 int os::Linux::get_our_sigflags(int sig) {
4687 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4688 return sigflags[sig];
4689 }
4691 void os::Linux::set_our_sigflags(int sig, int flags) {
4692 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4693 sigflags[sig] = flags;
4694 }
4696 void os::Linux::set_signal_handler(int sig, bool set_installed) {
4697 // Check for overwrite.
4698 struct sigaction oldAct;
4699 sigaction(sig, (struct sigaction*)NULL, &oldAct);
4701 void* oldhand = oldAct.sa_sigaction
4702 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4703 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4704 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
4705 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
4706 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
4707 if (AllowUserSignalHandlers || !set_installed) {
4708 // Do not overwrite; user takes responsibility to forward to us.
4709 return;
4710 } else if (UseSignalChaining) {
4711 // save the old handler in jvm
4712 save_preinstalled_handler(sig, oldAct);
4713 // libjsig also interposes the sigaction() call below and saves the
4714 // old sigaction on it own.
4715 } else {
4716 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
4717 "%#lx for signal %d.", (long)oldhand, sig));
4718 }
4719 }
4721 struct sigaction sigAct;
4722 sigfillset(&(sigAct.sa_mask));
4723 sigAct.sa_handler = SIG_DFL;
4724 if (!set_installed) {
4725 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4726 } else {
4727 sigAct.sa_sigaction = signalHandler;
4728 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
4729 }
4730 // Save flags, which are set by ours
4731 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
4732 sigflags[sig] = sigAct.sa_flags;
4734 int ret = sigaction(sig, &sigAct, &oldAct);
4735 assert(ret == 0, "check");
4737 void* oldhand2 = oldAct.sa_sigaction
4738 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
4739 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
4740 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
4741 }
4743 // install signal handlers for signals that HotSpot needs to
4744 // handle in order to support Java-level exception handling.
4746 void os::Linux::install_signal_handlers() {
4747 if (!signal_handlers_are_installed) {
4748 signal_handlers_are_installed = true;
4750 // signal-chaining
4751 typedef void (*signal_setting_t)();
4752 signal_setting_t begin_signal_setting = NULL;
4753 signal_setting_t end_signal_setting = NULL;
4754 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4755 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
4756 if (begin_signal_setting != NULL) {
4757 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
4758 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
4759 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
4760 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
4761 libjsig_is_loaded = true;
4762 assert(UseSignalChaining, "should enable signal-chaining");
4763 }
4764 if (libjsig_is_loaded) {
4765 // Tell libjsig jvm is setting signal handlers
4766 (*begin_signal_setting)();
4767 }
4769 set_signal_handler(SIGSEGV, true);
4770 set_signal_handler(SIGPIPE, true);
4771 set_signal_handler(SIGBUS, true);
4772 set_signal_handler(SIGILL, true);
4773 set_signal_handler(SIGFPE, true);
4774 #if defined(PPC64)
4775 set_signal_handler(SIGTRAP, true);
4776 #endif
4777 set_signal_handler(SIGXFSZ, true);
4779 if (libjsig_is_loaded) {
4780 // Tell libjsig jvm finishes setting signal handlers
4781 (*end_signal_setting)();
4782 }
4784 // We don't activate signal checker if libjsig is in place, we trust ourselves
4785 // and if UserSignalHandler is installed all bets are off.
4786 // Log that signal checking is off only if -verbose:jni is specified.
4787 if (CheckJNICalls) {
4788 if (libjsig_is_loaded) {
4789 if (PrintJNIResolving) {
4790 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
4791 }
4792 check_signals = false;
4793 }
4794 if (AllowUserSignalHandlers) {
4795 if (PrintJNIResolving) {
4796 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
4797 }
4798 check_signals = false;
4799 }
4800 }
4801 }
4802 }
4804 // This is the fastest way to get thread cpu time on Linux.
4805 // Returns cpu time (user+sys) for any thread, not only for current.
4806 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
4807 // It might work on 2.6.10+ with a special kernel/glibc patch.
4808 // For reference, please, see IEEE Std 1003.1-2004:
4809 // http://www.unix.org/single_unix_specification
4811 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
4812 struct timespec tp;
4813 int rc = os::Linux::clock_gettime(clockid, &tp);
4814 assert(rc == 0, "clock_gettime is expected to return 0 code");
4816 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
4817 }
4819 /////
4820 // glibc on Linux platform uses non-documented flag
4821 // to indicate, that some special sort of signal
4822 // trampoline is used.
4823 // We will never set this flag, and we should
4824 // ignore this flag in our diagnostic
4825 #ifdef SIGNIFICANT_SIGNAL_MASK
4826 #undef SIGNIFICANT_SIGNAL_MASK
4827 #endif
4828 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
4830 static const char* get_signal_handler_name(address handler,
4831 char* buf, int buflen) {
4832 int offset = 0;
4833 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
4834 if (found) {
4835 // skip directory names
4836 const char *p1, *p2;
4837 p1 = buf;
4838 size_t len = strlen(os::file_separator());
4839 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
4840 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
4841 } else {
4842 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
4843 }
4844 return buf;
4845 }
4847 static void print_signal_handler(outputStream* st, int sig,
4848 char* buf, size_t buflen) {
4849 struct sigaction sa;
4851 sigaction(sig, NULL, &sa);
4853 // See comment for SIGNIFICANT_SIGNAL_MASK define
4854 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4856 st->print("%s: ", os::exception_name(sig, buf, buflen));
4858 address handler = (sa.sa_flags & SA_SIGINFO)
4859 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
4860 : CAST_FROM_FN_PTR(address, sa.sa_handler);
4862 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
4863 st->print("SIG_DFL");
4864 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
4865 st->print("SIG_IGN");
4866 } else {
4867 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
4868 }
4870 st->print(", sa_mask[0]=");
4871 os::Posix::print_signal_set_short(st, &sa.sa_mask);
4873 address rh = VMError::get_resetted_sighandler(sig);
4874 // May be, handler was resetted by VMError?
4875 if(rh != NULL) {
4876 handler = rh;
4877 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
4878 }
4880 st->print(", sa_flags=");
4881 os::Posix::print_sa_flags(st, sa.sa_flags);
4883 // Check: is it our handler?
4884 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
4885 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
4886 // It is our signal handler
4887 // check for flags, reset system-used one!
4888 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
4889 st->print(
4890 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
4891 os::Linux::get_our_sigflags(sig));
4892 }
4893 }
4894 st->cr();
4895 }
4898 #define DO_SIGNAL_CHECK(sig) \
4899 if (!sigismember(&check_signal_done, sig)) \
4900 os::Linux::check_signal_handler(sig)
4902 // This method is a periodic task to check for misbehaving JNI applications
4903 // under CheckJNI, we can add any periodic checks here
4905 void os::run_periodic_checks() {
4907 if (check_signals == false) return;
4909 // SEGV and BUS if overridden could potentially prevent
4910 // generation of hs*.log in the event of a crash, debugging
4911 // such a case can be very challenging, so we absolutely
4912 // check the following for a good measure:
4913 DO_SIGNAL_CHECK(SIGSEGV);
4914 DO_SIGNAL_CHECK(SIGILL);
4915 DO_SIGNAL_CHECK(SIGFPE);
4916 DO_SIGNAL_CHECK(SIGBUS);
4917 DO_SIGNAL_CHECK(SIGPIPE);
4918 DO_SIGNAL_CHECK(SIGXFSZ);
4919 #if defined(PPC64)
4920 DO_SIGNAL_CHECK(SIGTRAP);
4921 #endif
4923 // ReduceSignalUsage allows the user to override these handlers
4924 // see comments at the very top and jvm_solaris.h
4925 if (!ReduceSignalUsage) {
4926 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4927 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4928 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4929 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4930 }
4932 DO_SIGNAL_CHECK(SR_signum);
4933 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4934 }
4936 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4938 static os_sigaction_t os_sigaction = NULL;
4940 void os::Linux::check_signal_handler(int sig) {
4941 char buf[O_BUFLEN];
4942 address jvmHandler = NULL;
4945 struct sigaction act;
4946 if (os_sigaction == NULL) {
4947 // only trust the default sigaction, in case it has been interposed
4948 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4949 if (os_sigaction == NULL) return;
4950 }
4952 os_sigaction(sig, (struct sigaction*)NULL, &act);
4955 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4957 address thisHandler = (act.sa_flags & SA_SIGINFO)
4958 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4959 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4962 switch(sig) {
4963 case SIGSEGV:
4964 case SIGBUS:
4965 case SIGFPE:
4966 case SIGPIPE:
4967 case SIGILL:
4968 case SIGXFSZ:
4969 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4970 break;
4972 case SHUTDOWN1_SIGNAL:
4973 case SHUTDOWN2_SIGNAL:
4974 case SHUTDOWN3_SIGNAL:
4975 case BREAK_SIGNAL:
4976 jvmHandler = (address)user_handler();
4977 break;
4979 case INTERRUPT_SIGNAL:
4980 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4981 break;
4983 default:
4984 if (sig == SR_signum) {
4985 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4986 } else {
4987 return;
4988 }
4989 break;
4990 }
4992 if (thisHandler != jvmHandler) {
4993 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4994 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4995 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4996 // No need to check this sig any longer
4997 sigaddset(&check_signal_done, sig);
4998 // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
4999 if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
5000 tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
5001 exception_name(sig, buf, O_BUFLEN));
5002 }
5003 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
5004 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
5005 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
5006 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
5007 // No need to check this sig any longer
5008 sigaddset(&check_signal_done, sig);
5009 }
5011 // Dump all the signal
5012 if (sigismember(&check_signal_done, sig)) {
5013 print_signal_handlers(tty, buf, O_BUFLEN);
5014 }
5015 }
5017 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
5019 extern bool signal_name(int signo, char* buf, size_t len);
5021 const char* os::exception_name(int exception_code, char* buf, size_t size) {
5022 if (0 < exception_code && exception_code <= SIGRTMAX) {
5023 // signal
5024 if (!signal_name(exception_code, buf, size)) {
5025 jio_snprintf(buf, size, "SIG%d", exception_code);
5026 }
5027 return buf;
5028 } else {
5029 return NULL;
5030 }
5031 }
5033 // this is called _before_ most of the global arguments have been parsed
5034 void os::init(void) {
5035 char dummy; /* used to get a guess on initial stack address */
5037 // With LinuxThreads the JavaMain thread pid (primordial thread)
5038 // is different than the pid of the java launcher thread.
5039 // So, on Linux, the launcher thread pid is passed to the VM
5040 // via the sun.java.launcher.pid property.
5041 // Use this property instead of getpid() if it was correctly passed.
5042 // See bug 6351349.
5043 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
5045 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
5047 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
5049 init_random(1234567);
5051 ThreadCritical::initialize();
5053 Linux::set_page_size(sysconf(_SC_PAGESIZE));
5054 if (Linux::page_size() == -1) {
5055 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
5056 strerror(errno)));
5057 }
5058 init_page_sizes((size_t) Linux::page_size());
5060 Linux::initialize_system_info();
5062 // _main_thread points to the thread that created/loaded the JVM.
5063 Linux::_main_thread = pthread_self();
5065 Linux::clock_init();
5066 initial_time_count = javaTimeNanos();
5068 // pthread_condattr initialization for monotonic clock
5069 int status;
5070 pthread_condattr_t* _condattr = os::Linux::condAttr();
5071 if ((status = pthread_condattr_init(_condattr)) != 0) {
5072 fatal(err_msg("pthread_condattr_init: %s", strerror(status)));
5073 }
5074 // Only set the clock if CLOCK_MONOTONIC is available
5075 if (Linux::supports_monotonic_clock()) {
5076 if ((status = pthread_condattr_setclock(_condattr, CLOCK_MONOTONIC)) != 0) {
5077 if (status == EINVAL) {
5078 warning("Unable to use monotonic clock with relative timed-waits" \
5079 " - changes to the time-of-day clock may have adverse affects");
5080 } else {
5081 fatal(err_msg("pthread_condattr_setclock: %s", strerror(status)));
5082 }
5083 }
5084 }
5085 // else it defaults to CLOCK_REALTIME
5087 pthread_mutex_init(&dl_mutex, NULL);
5089 // If the pagesize of the VM is greater than 8K determine the appropriate
5090 // number of initial guard pages. The user can change this with the
5091 // command line arguments, if needed.
5092 if (vm_page_size() > (int)Linux::vm_default_page_size()) {
5093 StackYellowPages = 1;
5094 StackRedPages = 1;
5095 StackShadowPages = round_to((StackShadowPages*Linux::vm_default_page_size()), vm_page_size()) / vm_page_size();
5096 }
5098 // retrieve entry point for pthread_setname_np
5099 Linux::_pthread_setname_np =
5100 (int(*)(pthread_t, const char*))dlsym(RTLD_DEFAULT, "pthread_setname_np");
5102 }
5104 // To install functions for atexit system call
5105 extern "C" {
5106 static void perfMemory_exit_helper() {
5107 perfMemory_exit();
5108 }
5109 }
5111 void os::pd_init_container_support() {
5112 OSContainer::init();
5113 }
5115 // this is called _after_ the global arguments have been parsed
5116 jint os::init_2(void)
5117 {
5118 Linux::fast_thread_clock_init();
5120 // Allocate a single page and mark it as readable for safepoint polling
5121 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
5122 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
5124 os::set_polling_page( polling_page );
5126 #ifndef PRODUCT
5127 if(Verbose && PrintMiscellaneous)
5128 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
5129 #endif
5131 if (!UseMembar) {
5132 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
5133 guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
5134 os::set_memory_serialize_page( mem_serialize_page );
5136 #ifndef PRODUCT
5137 if(Verbose && PrintMiscellaneous)
5138 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
5139 #endif
5140 }
5142 // initialize suspend/resume support - must do this before signal_sets_init()
5143 if (SR_initialize() != 0) {
5144 perror("SR_initialize failed");
5145 return JNI_ERR;
5146 }
5148 Linux::signal_sets_init();
5149 Linux::install_signal_handlers();
5151 // Check minimum allowable stack size for thread creation and to initialize
5152 // the java system classes, including StackOverflowError - depends on page
5153 // size. Add a page for compiler2 recursion in main thread.
5154 // Add in 2*BytesPerWord times page size to account for VM stack during
5155 // class initialization depending on 32 or 64 bit VM.
5156 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
5157 (size_t)(StackYellowPages+StackRedPages+StackShadowPages) * Linux::page_size() +
5158 (2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::vm_default_page_size());
5160 size_t threadStackSizeInBytes = ThreadStackSize * K;
5161 if (threadStackSizeInBytes != 0 &&
5162 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
5163 tty->print_cr("\nThe stack size specified is too small, "
5164 "Specify at least %dk",
5165 os::Linux::min_stack_allowed/ K);
5166 return JNI_ERR;
5167 }
5169 // Make the stack size a multiple of the page size so that
5170 // the yellow/red zones can be guarded.
5171 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
5172 vm_page_size()));
5174 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
5176 #if defined(IA32)
5177 workaround_expand_exec_shield_cs_limit();
5178 #endif
5180 Linux::libpthread_init();
5181 if (PrintMiscellaneous && (Verbose || WizardMode)) {
5182 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
5183 Linux::glibc_version(), Linux::libpthread_version(),
5184 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
5185 }
5187 if (UseNUMA) {
5188 if (!Linux::libnuma_init()) {
5189 UseNUMA = false;
5190 } else {
5191 if ((Linux::numa_max_node() < 1)) {
5192 // There's only one node(they start from 0), disable NUMA.
5193 UseNUMA = false;
5194 }
5195 }
5196 // With SHM and HugeTLBFS large pages we cannot uncommit a page, so there's no way
5197 // we can make the adaptive lgrp chunk resizing work. If the user specified
5198 // both UseNUMA and UseLargePages (or UseSHM/UseHugeTLBFS) on the command line - warn and
5199 // disable adaptive resizing.
5200 if (UseNUMA && UseLargePages && !can_commit_large_page_memory()) {
5201 if (FLAG_IS_DEFAULT(UseNUMA)) {
5202 UseNUMA = false;
5203 } else {
5204 if (FLAG_IS_DEFAULT(UseLargePages) &&
5205 FLAG_IS_DEFAULT(UseSHM) &&
5206 FLAG_IS_DEFAULT(UseHugeTLBFS)) {
5207 UseLargePages = false;
5208 } else {
5209 warning("UseNUMA is not fully compatible with SHM/HugeTLBFS large pages, disabling adaptive resizing");
5210 UseAdaptiveSizePolicy = false;
5211 UseAdaptiveNUMAChunkSizing = false;
5212 }
5213 }
5214 }
5215 if (!UseNUMA && ForceNUMA) {
5216 UseNUMA = true;
5217 }
5218 }
5220 if (MaxFDLimit) {
5221 // set the number of file descriptors to max. print out error
5222 // if getrlimit/setrlimit fails but continue regardless.
5223 struct rlimit nbr_files;
5224 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
5225 if (status != 0) {
5226 if (PrintMiscellaneous && (Verbose || WizardMode))
5227 perror("os::init_2 getrlimit failed");
5228 } else {
5229 nbr_files.rlim_cur = nbr_files.rlim_max;
5230 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
5231 if (status != 0) {
5232 if (PrintMiscellaneous && (Verbose || WizardMode))
5233 perror("os::init_2 setrlimit failed");
5234 }
5235 }
5236 }
5238 // Initialize lock used to serialize thread creation (see os::create_thread)
5239 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
5241 // at-exit methods are called in the reverse order of their registration.
5242 // atexit functions are called on return from main or as a result of a
5243 // call to exit(3C). There can be only 32 of these functions registered
5244 // and atexit() does not set errno.
5246 if (PerfAllowAtExitRegistration) {
5247 // only register atexit functions if PerfAllowAtExitRegistration is set.
5248 // atexit functions can be delayed until process exit time, which
5249 // can be problematic for embedded VM situations. Embedded VMs should
5250 // call DestroyJavaVM() to assure that VM resources are released.
5252 // note: perfMemory_exit_helper atexit function may be removed in
5253 // the future if the appropriate cleanup code can be added to the
5254 // VM_Exit VMOperation's doit method.
5255 if (atexit(perfMemory_exit_helper) != 0) {
5256 warning("os::init_2 atexit(perfMemory_exit_helper) failed");
5257 }
5258 }
5260 // initialize thread priority policy
5261 prio_init();
5263 return JNI_OK;
5264 }
5266 // Mark the polling page as unreadable
5267 void os::make_polling_page_unreadable(void) {
5268 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
5269 fatal("Could not disable polling page");
5270 };
5272 // Mark the polling page as readable
5273 void os::make_polling_page_readable(void) {
5274 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
5275 fatal("Could not enable polling page");
5276 }
5277 };
5279 static int os_cpu_count(const cpu_set_t* cpus) {
5280 int count = 0;
5281 // only look up to the number of configured processors
5282 for (int i = 0; i < os::processor_count(); i++) {
5283 if (CPU_ISSET(i, cpus)) {
5284 count++;
5285 }
5286 }
5287 return count;
5288 }
5290 // Get the current number of available processors for this process.
5291 // This value can change at any time during a process's lifetime.
5292 // sched_getaffinity gives an accurate answer as it accounts for cpusets.
5293 // If anything goes wrong we fallback to returning the number of online
5294 // processors - which can be greater than the number available to the process.
5295 int os::Linux::active_processor_count() {
5296 cpu_set_t cpus; // can represent at most 1024 (CPU_SETSIZE) processors
5297 int cpus_size = sizeof(cpu_set_t);
5298 int cpu_count = 0;
5300 // pid 0 means the current thread - which we have to assume represents the process
5301 if (sched_getaffinity(0, cpus_size, &cpus) == 0) {
5302 cpu_count = os_cpu_count(&cpus);
5303 if (PrintActiveCpus) {
5304 tty->print_cr("active_processor_count: sched_getaffinity processor count: %d", cpu_count);
5305 }
5306 }
5307 else {
5308 cpu_count = ::sysconf(_SC_NPROCESSORS_ONLN);
5309 warning("sched_getaffinity failed (%s)- using online processor count (%d) "
5310 "which may exceed available processors", strerror(errno), cpu_count);
5311 }
5313 assert(cpu_count > 0 && cpu_count <= os::processor_count(), "sanity check");
5314 return cpu_count;
5315 }
5317 // Determine the active processor count from one of
5318 // three different sources:
5319 //
5320 // 1. User option -XX:ActiveProcessorCount
5321 // 2. kernel os calls (sched_getaffinity or sysconf(_SC_NPROCESSORS_ONLN)
5322 // 3. extracted from cgroup cpu subsystem (shares and quotas)
5323 //
5324 // Option 1, if specified, will always override.
5325 // If the cgroup subsystem is active and configured, we
5326 // will return the min of the cgroup and option 2 results.
5327 // This is required since tools, such as numactl, that
5328 // alter cpu affinity do not update cgroup subsystem
5329 // cpuset configuration files.
5330 int os::active_processor_count() {
5331 // User has overridden the number of active processors
5332 if (ActiveProcessorCount > 0) {
5333 if (PrintActiveCpus) {
5334 tty->print_cr("active_processor_count: "
5335 "active processor count set by user : %d",
5336 ActiveProcessorCount);
5337 }
5338 return ActiveProcessorCount;
5339 }
5341 int active_cpus;
5342 if (OSContainer::is_containerized()) {
5343 active_cpus = OSContainer::active_processor_count();
5344 if (PrintActiveCpus) {
5345 tty->print_cr("active_processor_count: determined by OSContainer: %d",
5346 active_cpus);
5347 }
5348 } else {
5349 active_cpus = os::Linux::active_processor_count();
5350 }
5352 return active_cpus;
5353 }
5355 void os::set_native_thread_name(const char *name) {
5356 if (Linux::_pthread_setname_np) {
5357 char buf [16]; // according to glibc manpage, 16 chars incl. '/0'
5358 snprintf(buf, sizeof(buf), "%s", name);
5359 buf[sizeof(buf) - 1] = '\0';
5360 const int rc = Linux::_pthread_setname_np(pthread_self(), buf);
5361 // ERANGE should not happen; all other errors should just be ignored.
5362 assert(rc != ERANGE, "pthread_setname_np failed");
5363 }
5364 }
5366 bool os::distribute_processes(uint length, uint* distribution) {
5367 // Not yet implemented.
5368 return false;
5369 }
5371 bool os::bind_to_processor(uint processor_id) {
5372 // Not yet implemented.
5373 return false;
5374 }
5376 ///
5378 void os::SuspendedThreadTask::internal_do_task() {
5379 if (do_suspend(_thread->osthread())) {
5380 SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
5381 do_task(context);
5382 do_resume(_thread->osthread());
5383 }
5384 }
5386 class PcFetcher : public os::SuspendedThreadTask {
5387 public:
5388 PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
5389 ExtendedPC result();
5390 protected:
5391 void do_task(const os::SuspendedThreadTaskContext& context);
5392 private:
5393 ExtendedPC _epc;
5394 };
5396 ExtendedPC PcFetcher::result() {
5397 guarantee(is_done(), "task is not done yet.");
5398 return _epc;
5399 }
5401 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
5402 Thread* thread = context.thread();
5403 OSThread* osthread = thread->osthread();
5404 if (osthread->ucontext() != NULL) {
5405 _epc = os::Linux::ucontext_get_pc((ucontext_t *) context.ucontext());
5406 } else {
5407 // NULL context is unexpected, double-check this is the VMThread
5408 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
5409 }
5410 }
5412 // Suspends the target using the signal mechanism and then grabs the PC before
5413 // resuming the target. Used by the flat-profiler only
5414 ExtendedPC os::get_thread_pc(Thread* thread) {
5415 // Make sure that it is called by the watcher for the VMThread
5416 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
5417 assert(thread->is_VM_thread(), "Can only be called for VMThread");
5419 PcFetcher fetcher(thread);
5420 fetcher.run();
5421 return fetcher.result();
5422 }
5424 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
5425 {
5426 if (is_NPTL()) {
5427 return pthread_cond_timedwait(_cond, _mutex, _abstime);
5428 } else {
5429 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
5430 // word back to default 64bit precision if condvar is signaled. Java
5431 // wants 53bit precision. Save and restore current value.
5432 int fpu = get_fpu_control_word();
5433 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
5434 set_fpu_control_word(fpu);
5435 return status;
5436 }
5437 }
5439 ////////////////////////////////////////////////////////////////////////////////
5440 // debug support
5442 bool os::find(address addr, outputStream* st) {
5443 Dl_info dlinfo;
5444 memset(&dlinfo, 0, sizeof(dlinfo));
5445 if (dladdr(addr, &dlinfo) != 0) {
5446 st->print(PTR_FORMAT ": ", addr);
5447 if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
5448 st->print("%s+%#x", dlinfo.dli_sname,
5449 addr - (intptr_t)dlinfo.dli_saddr);
5450 } else if (dlinfo.dli_fbase != NULL) {
5451 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
5452 } else {
5453 st->print("<absolute address>");
5454 }
5455 if (dlinfo.dli_fname != NULL) {
5456 st->print(" in %s", dlinfo.dli_fname);
5457 }
5458 if (dlinfo.dli_fbase != NULL) {
5459 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
5460 }
5461 st->cr();
5463 if (Verbose) {
5464 // decode some bytes around the PC
5465 address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
5466 address end = clamp_address_in_page(addr+40, addr, os::vm_page_size());
5467 address lowest = (address) dlinfo.dli_sname;
5468 if (!lowest) lowest = (address) dlinfo.dli_fbase;
5469 if (begin < lowest) begin = lowest;
5470 Dl_info dlinfo2;
5471 if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
5472 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
5473 end = (address) dlinfo2.dli_saddr;
5474 Disassembler::decode(begin, end, st);
5475 }
5476 return true;
5477 }
5478 return false;
5479 }
5481 ////////////////////////////////////////////////////////////////////////////////
5482 // misc
5484 // This does not do anything on Linux. This is basically a hook for being
5485 // able to use structured exception handling (thread-local exception filters)
5486 // on, e.g., Win32.
5487 void
5488 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
5489 JavaCallArguments* args, Thread* thread) {
5490 f(value, method, args, thread);
5491 }
5493 void os::print_statistics() {
5494 }
5496 int os::message_box(const char* title, const char* message) {
5497 int i;
5498 fdStream err(defaultStream::error_fd());
5499 for (i = 0; i < 78; i++) err.print_raw("=");
5500 err.cr();
5501 err.print_raw_cr(title);
5502 for (i = 0; i < 78; i++) err.print_raw("-");
5503 err.cr();
5504 err.print_raw_cr(message);
5505 for (i = 0; i < 78; i++) err.print_raw("=");
5506 err.cr();
5508 char buf[16];
5509 // Prevent process from exiting upon "read error" without consuming all CPU
5510 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
5512 return buf[0] == 'y' || buf[0] == 'Y';
5513 }
5515 int os::stat(const char *path, struct stat *sbuf) {
5516 char pathbuf[MAX_PATH];
5517 if (strlen(path) > MAX_PATH - 1) {
5518 errno = ENAMETOOLONG;
5519 return -1;
5520 }
5521 os::native_path(strcpy(pathbuf, path));
5522 return ::stat(pathbuf, sbuf);
5523 }
5525 bool os::check_heap(bool force) {
5526 return true;
5527 }
5529 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
5530 return ::vsnprintf(buf, count, format, args);
5531 }
5533 // Is a (classpath) directory empty?
5534 bool os::dir_is_empty(const char* path) {
5535 DIR *dir = NULL;
5536 struct dirent *ptr;
5538 dir = opendir(path);
5539 if (dir == NULL) return true;
5541 /* Scan the directory */
5542 bool result = true;
5543 while (result && (ptr = readdir(dir)) != NULL) {
5544 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
5545 result = false;
5546 }
5547 }
5548 closedir(dir);
5549 return result;
5550 }
5552 // This code originates from JDK's sysOpen and open64_w
5553 // from src/solaris/hpi/src/system_md.c
5555 #ifndef O_DELETE
5556 #define O_DELETE 0x10000
5557 #endif
5559 // Open a file. Unlink the file immediately after open returns
5560 // if the specified oflag has the O_DELETE flag set.
5561 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
5563 int os::open(const char *path, int oflag, int mode) {
5565 if (strlen(path) > MAX_PATH - 1) {
5566 errno = ENAMETOOLONG;
5567 return -1;
5568 }
5569 int fd;
5570 int o_delete = (oflag & O_DELETE);
5571 oflag = oflag & ~O_DELETE;
5573 fd = ::open64(path, oflag, mode);
5574 if (fd == -1) return -1;
5576 //If the open succeeded, the file might still be a directory
5577 {
5578 struct stat64 buf64;
5579 int ret = ::fstat64(fd, &buf64);
5580 int st_mode = buf64.st_mode;
5582 if (ret != -1) {
5583 if ((st_mode & S_IFMT) == S_IFDIR) {
5584 errno = EISDIR;
5585 ::close(fd);
5586 return -1;
5587 }
5588 } else {
5589 ::close(fd);
5590 return -1;
5591 }
5592 }
5594 /*
5595 * All file descriptors that are opened in the JVM and not
5596 * specifically destined for a subprocess should have the
5597 * close-on-exec flag set. If we don't set it, then careless 3rd
5598 * party native code might fork and exec without closing all
5599 * appropriate file descriptors (e.g. as we do in closeDescriptors in
5600 * UNIXProcess.c), and this in turn might:
5601 *
5602 * - cause end-of-file to fail to be detected on some file
5603 * descriptors, resulting in mysterious hangs, or
5604 *
5605 * - might cause an fopen in the subprocess to fail on a system
5606 * suffering from bug 1085341.
5607 *
5608 * (Yes, the default setting of the close-on-exec flag is a Unix
5609 * design flaw)
5610 *
5611 * See:
5612 * 1085341: 32-bit stdio routines should support file descriptors >255
5613 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
5614 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
5615 */
5616 #ifdef FD_CLOEXEC
5617 {
5618 int flags = ::fcntl(fd, F_GETFD);
5619 if (flags != -1)
5620 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
5621 }
5622 #endif
5624 if (o_delete != 0) {
5625 ::unlink(path);
5626 }
5627 return fd;
5628 }
5631 // create binary file, rewriting existing file if required
5632 int os::create_binary_file(const char* path, bool rewrite_existing) {
5633 int oflags = O_WRONLY | O_CREAT;
5634 if (!rewrite_existing) {
5635 oflags |= O_EXCL;
5636 }
5637 return ::open64(path, oflags, S_IREAD | S_IWRITE);
5638 }
5640 // return current position of file pointer
5641 jlong os::current_file_offset(int fd) {
5642 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
5643 }
5645 // move file pointer to the specified offset
5646 jlong os::seek_to_file_offset(int fd, jlong offset) {
5647 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
5648 }
5650 // This code originates from JDK's sysAvailable
5651 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
5653 int os::available(int fd, jlong *bytes) {
5654 jlong cur, end;
5655 int mode;
5656 struct stat64 buf64;
5658 if (::fstat64(fd, &buf64) >= 0) {
5659 mode = buf64.st_mode;
5660 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
5661 /*
5662 * XXX: is the following call interruptible? If so, this might
5663 * need to go through the INTERRUPT_IO() wrapper as for other
5664 * blocking, interruptible calls in this file.
5665 */
5666 int n;
5667 if (::ioctl(fd, FIONREAD, &n) >= 0) {
5668 *bytes = n;
5669 return 1;
5670 }
5671 }
5672 }
5673 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
5674 return 0;
5675 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
5676 return 0;
5677 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
5678 return 0;
5679 }
5680 *bytes = end - cur;
5681 return 1;
5682 }
5684 int os::socket_available(int fd, jint *pbytes) {
5685 // Linux doc says EINTR not returned, unlike Solaris
5686 int ret = ::ioctl(fd, FIONREAD, pbytes);
5688 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
5689 // is expected to return 0 on failure and 1 on success to the jdk.
5690 return (ret < 0) ? 0 : 1;
5691 }
5693 // Map a block of memory.
5694 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
5695 char *addr, size_t bytes, bool read_only,
5696 bool allow_exec) {
5697 int prot;
5698 int flags = MAP_PRIVATE;
5700 if (read_only) {
5701 prot = PROT_READ;
5702 } else {
5703 prot = PROT_READ | PROT_WRITE;
5704 }
5706 if (allow_exec) {
5707 prot |= PROT_EXEC;
5708 }
5710 if (addr != NULL) {
5711 flags |= MAP_FIXED;
5712 }
5714 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
5715 fd, file_offset);
5716 if (mapped_address == MAP_FAILED) {
5717 return NULL;
5718 }
5719 return mapped_address;
5720 }
5723 // Remap a block of memory.
5724 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
5725 char *addr, size_t bytes, bool read_only,
5726 bool allow_exec) {
5727 // same as map_memory() on this OS
5728 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
5729 allow_exec);
5730 }
5733 // Unmap a block of memory.
5734 bool os::pd_unmap_memory(char* addr, size_t bytes) {
5735 return munmap(addr, bytes) == 0;
5736 }
5738 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
5740 static clockid_t thread_cpu_clockid(Thread* thread) {
5741 pthread_t tid = thread->osthread()->pthread_id();
5742 clockid_t clockid;
5744 // Get thread clockid
5745 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
5746 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
5747 return clockid;
5748 }
5750 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
5751 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
5752 // of a thread.
5753 //
5754 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
5755 // the fast estimate available on the platform.
5757 jlong os::current_thread_cpu_time() {
5758 if (os::Linux::supports_fast_thread_cpu_time()) {
5759 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5760 } else {
5761 // return user + sys since the cost is the same
5762 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
5763 }
5764 }
5766 jlong os::thread_cpu_time(Thread* thread) {
5767 // consistent with what current_thread_cpu_time() returns
5768 if (os::Linux::supports_fast_thread_cpu_time()) {
5769 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5770 } else {
5771 return slow_thread_cpu_time(thread, true /* user + sys */);
5772 }
5773 }
5775 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
5776 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5777 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
5778 } else {
5779 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
5780 }
5781 }
5783 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5784 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
5785 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
5786 } else {
5787 return slow_thread_cpu_time(thread, user_sys_cpu_time);
5788 }
5789 }
5791 //
5792 // -1 on error.
5793 //
5795 PRAGMA_DIAG_PUSH
5796 PRAGMA_FORMAT_NONLITERAL_IGNORED
5797 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
5798 static bool proc_task_unchecked = true;
5799 static const char *proc_stat_path = "/proc/%d/stat";
5800 pid_t tid = thread->osthread()->thread_id();
5801 char *s;
5802 char stat[2048];
5803 int statlen;
5804 char proc_name[64];
5805 int count;
5806 long sys_time, user_time;
5807 char cdummy;
5808 int idummy;
5809 long ldummy;
5810 FILE *fp;
5812 // The /proc/<tid>/stat aggregates per-process usage on
5813 // new Linux kernels 2.6+ where NPTL is supported.
5814 // The /proc/self/task/<tid>/stat still has the per-thread usage.
5815 // See bug 6328462.
5816 // There possibly can be cases where there is no directory
5817 // /proc/self/task, so we check its availability.
5818 if (proc_task_unchecked && os::Linux::is_NPTL()) {
5819 // This is executed only once
5820 proc_task_unchecked = false;
5821 fp = fopen("/proc/self/task", "r");
5822 if (fp != NULL) {
5823 proc_stat_path = "/proc/self/task/%d/stat";
5824 fclose(fp);
5825 }
5826 }
5828 sprintf(proc_name, proc_stat_path, tid);
5829 fp = fopen(proc_name, "r");
5830 if ( fp == NULL ) return -1;
5831 statlen = fread(stat, 1, 2047, fp);
5832 stat[statlen] = '\0';
5833 fclose(fp);
5835 // Skip pid and the command string. Note that we could be dealing with
5836 // weird command names, e.g. user could decide to rename java launcher
5837 // to "java 1.4.2 :)", then the stat file would look like
5838 // 1234 (java 1.4.2 :)) R ... ...
5839 // We don't really need to know the command string, just find the last
5840 // occurrence of ")" and then start parsing from there. See bug 4726580.
5841 s = strrchr(stat, ')');
5842 if (s == NULL ) return -1;
5844 // Skip blank chars
5845 do s++; while (isspace(*s));
5847 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
5848 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
5849 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
5850 &user_time, &sys_time);
5851 if ( count != 13 ) return -1;
5852 if (user_sys_cpu_time) {
5853 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
5854 } else {
5855 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
5856 }
5857 }
5858 PRAGMA_DIAG_POP
5860 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5861 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5862 info_ptr->may_skip_backward = false; // elapsed time not wall time
5863 info_ptr->may_skip_forward = false; // elapsed time not wall time
5864 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5865 }
5867 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
5868 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
5869 info_ptr->may_skip_backward = false; // elapsed time not wall time
5870 info_ptr->may_skip_forward = false; // elapsed time not wall time
5871 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
5872 }
5874 bool os::is_thread_cpu_time_supported() {
5875 return true;
5876 }
5878 // System loadavg support. Returns -1 if load average cannot be obtained.
5879 // Linux doesn't yet have a (official) notion of processor sets,
5880 // so just return the system wide load average.
5881 int os::loadavg(double loadavg[], int nelem) {
5882 return ::getloadavg(loadavg, nelem);
5883 }
5885 void os::pause() {
5886 char filename[MAX_PATH];
5887 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
5888 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
5889 } else {
5890 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
5891 }
5893 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
5894 if (fd != -1) {
5895 struct stat buf;
5896 ::close(fd);
5897 while (::stat(filename, &buf) == 0) {
5898 (void)::poll(NULL, 0, 100);
5899 }
5900 } else {
5901 jio_fprintf(stderr,
5902 "Could not open pause file '%s', continuing immediately.\n", filename);
5903 }
5904 }
5907 // Refer to the comments in os_solaris.cpp park-unpark.
5908 //
5909 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
5910 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
5911 // For specifics regarding the bug see GLIBC BUGID 261237 :
5912 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
5913 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
5914 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
5915 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
5916 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
5917 // and monitorenter when we're using 1-0 locking. All those operations may result in
5918 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
5919 // of libpthread avoids the problem, but isn't practical.
5920 //
5921 // Possible remedies:
5922 //
5923 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
5924 // This is palliative and probabilistic, however. If the thread is preempted
5925 // between the call to compute_abstime() and pthread_cond_timedwait(), more
5926 // than the minimum period may have passed, and the abstime may be stale (in the
5927 // past) resultin in a hang. Using this technique reduces the odds of a hang
5928 // but the JVM is still vulnerable, particularly on heavily loaded systems.
5929 //
5930 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
5931 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
5932 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
5933 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
5934 // thread.
5935 //
5936 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
5937 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
5938 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
5939 // This also works well. In fact it avoids kernel-level scalability impediments
5940 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
5941 // timers in a graceful fashion.
5942 //
5943 // 4. When the abstime value is in the past it appears that control returns
5944 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
5945 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
5946 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
5947 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
5948 // It may be possible to avoid reinitialization by checking the return
5949 // value from pthread_cond_timedwait(). In addition to reinitializing the
5950 // condvar we must establish the invariant that cond_signal() is only called
5951 // within critical sections protected by the adjunct mutex. This prevents
5952 // cond_signal() from "seeing" a condvar that's in the midst of being
5953 // reinitialized or that is corrupt. Sadly, this invariant obviates the
5954 // desirable signal-after-unlock optimization that avoids futile context switching.
5955 //
5956 // I'm also concerned that some versions of NTPL might allocate an auxilliary
5957 // structure when a condvar is used or initialized. cond_destroy() would
5958 // release the helper structure. Our reinitialize-after-timedwait fix
5959 // put excessive stress on malloc/free and locks protecting the c-heap.
5960 //
5961 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
5962 // It may be possible to refine (4) by checking the kernel and NTPL verisons
5963 // and only enabling the work-around for vulnerable environments.
5965 // utility to compute the abstime argument to timedwait:
5966 // millis is the relative timeout time
5967 // abstime will be the absolute timeout time
5968 // TODO: replace compute_abstime() with unpackTime()
5970 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
5971 if (millis < 0) millis = 0;
5973 jlong seconds = millis / 1000;
5974 millis %= 1000;
5975 if (seconds > 50000000) { // see man cond_timedwait(3T)
5976 seconds = 50000000;
5977 }
5979 if (os::Linux::supports_monotonic_clock()) {
5980 struct timespec now;
5981 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
5982 assert_status(status == 0, status, "clock_gettime");
5983 abstime->tv_sec = now.tv_sec + seconds;
5984 long nanos = now.tv_nsec + millis * NANOSECS_PER_MILLISEC;
5985 if (nanos >= NANOSECS_PER_SEC) {
5986 abstime->tv_sec += 1;
5987 nanos -= NANOSECS_PER_SEC;
5988 }
5989 abstime->tv_nsec = nanos;
5990 } else {
5991 struct timeval now;
5992 int status = gettimeofday(&now, NULL);
5993 assert(status == 0, "gettimeofday");
5994 abstime->tv_sec = now.tv_sec + seconds;
5995 long usec = now.tv_usec + millis * 1000;
5996 if (usec >= 1000000) {
5997 abstime->tv_sec += 1;
5998 usec -= 1000000;
5999 }
6000 abstime->tv_nsec = usec * 1000;
6001 }
6002 return abstime;
6003 }
6006 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
6007 // Conceptually TryPark() should be equivalent to park(0).
6009 int os::PlatformEvent::TryPark() {
6010 for (;;) {
6011 const int v = _Event ;
6012 guarantee ((v == 0) || (v == 1), "invariant") ;
6013 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
6014 }
6015 }
6017 void os::PlatformEvent::park() { // AKA "down()"
6018 // Invariant: Only the thread associated with the Event/PlatformEvent
6019 // may call park().
6020 // TODO: assert that _Assoc != NULL or _Assoc == Self
6021 int v ;
6022 for (;;) {
6023 v = _Event ;
6024 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
6025 }
6026 guarantee (v >= 0, "invariant") ;
6027 if (v == 0) {
6028 // Do this the hard way by blocking ...
6029 int status = pthread_mutex_lock(_mutex);
6030 assert_status(status == 0, status, "mutex_lock");
6031 guarantee (_nParked == 0, "invariant") ;
6032 ++ _nParked ;
6033 while (_Event < 0) {
6034 status = pthread_cond_wait(_cond, _mutex);
6035 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
6036 // Treat this the same as if the wait was interrupted
6037 if (status == ETIME) { status = EINTR; }
6038 assert_status(status == 0 || status == EINTR, status, "cond_wait");
6039 }
6040 -- _nParked ;
6042 _Event = 0 ;
6043 status = pthread_mutex_unlock(_mutex);
6044 assert_status(status == 0, status, "mutex_unlock");
6045 // Paranoia to ensure our locked and lock-free paths interact
6046 // correctly with each other.
6047 OrderAccess::fence();
6048 }
6049 guarantee (_Event >= 0, "invariant") ;
6050 }
6052 int os::PlatformEvent::park(jlong millis) {
6053 guarantee (_nParked == 0, "invariant") ;
6055 int v ;
6056 for (;;) {
6057 v = _Event ;
6058 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
6059 }
6060 guarantee (v >= 0, "invariant") ;
6061 if (v != 0) return OS_OK ;
6063 // We do this the hard way, by blocking the thread.
6064 // Consider enforcing a minimum timeout value.
6065 struct timespec abst;
6066 compute_abstime(&abst, millis);
6068 int ret = OS_TIMEOUT;
6069 int status = pthread_mutex_lock(_mutex);
6070 assert_status(status == 0, status, "mutex_lock");
6071 guarantee (_nParked == 0, "invariant") ;
6072 ++_nParked ;
6074 // Object.wait(timo) will return because of
6075 // (a) notification
6076 // (b) timeout
6077 // (c) thread.interrupt
6078 //
6079 // Thread.interrupt and object.notify{All} both call Event::set.
6080 // That is, we treat thread.interrupt as a special case of notification.
6081 // The underlying Solaris implementation, cond_timedwait, admits
6082 // spurious/premature wakeups, but the JLS/JVM spec prevents the
6083 // JVM from making those visible to Java code. As such, we must
6084 // filter out spurious wakeups. We assume all ETIME returns are valid.
6085 //
6086 // TODO: properly differentiate simultaneous notify+interrupt.
6087 // In that case, we should propagate the notify to another waiter.
6089 while (_Event < 0) {
6090 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
6091 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
6092 pthread_cond_destroy (_cond);
6093 pthread_cond_init (_cond, os::Linux::condAttr()) ;
6094 }
6095 assert_status(status == 0 || status == EINTR ||
6096 status == ETIME || status == ETIMEDOUT,
6097 status, "cond_timedwait");
6098 if (!FilterSpuriousWakeups) break ; // previous semantics
6099 if (status == ETIME || status == ETIMEDOUT) break ;
6100 // We consume and ignore EINTR and spurious wakeups.
6101 }
6102 --_nParked ;
6103 if (_Event >= 0) {
6104 ret = OS_OK;
6105 }
6106 _Event = 0 ;
6107 status = pthread_mutex_unlock(_mutex);
6108 assert_status(status == 0, status, "mutex_unlock");
6109 assert (_nParked == 0, "invariant") ;
6110 // Paranoia to ensure our locked and lock-free paths interact
6111 // correctly with each other.
6112 OrderAccess::fence();
6113 return ret;
6114 }
6116 void os::PlatformEvent::unpark() {
6117 // Transitions for _Event:
6118 // 0 :=> 1
6119 // 1 :=> 1
6120 // -1 :=> either 0 or 1; must signal target thread
6121 // That is, we can safely transition _Event from -1 to either
6122 // 0 or 1. Forcing 1 is slightly more efficient for back-to-back
6123 // unpark() calls.
6124 // See also: "Semaphores in Plan 9" by Mullender & Cox
6125 //
6126 // Note: Forcing a transition from "-1" to "1" on an unpark() means
6127 // that it will take two back-to-back park() calls for the owning
6128 // thread to block. This has the benefit of forcing a spurious return
6129 // from the first park() call after an unpark() call which will help
6130 // shake out uses of park() and unpark() without condition variables.
6132 if (Atomic::xchg(1, &_Event) >= 0) return;
6134 // Wait for the thread associated with the event to vacate
6135 int status = pthread_mutex_lock(_mutex);
6136 assert_status(status == 0, status, "mutex_lock");
6137 int AnyWaiters = _nParked;
6138 assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
6139 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
6140 AnyWaiters = 0;
6141 pthread_cond_signal(_cond);
6142 }
6143 status = pthread_mutex_unlock(_mutex);
6144 assert_status(status == 0, status, "mutex_unlock");
6145 if (AnyWaiters != 0) {
6146 status = pthread_cond_signal(_cond);
6147 assert_status(status == 0, status, "cond_signal");
6148 }
6150 // Note that we signal() _after dropping the lock for "immortal" Events.
6151 // This is safe and avoids a common class of futile wakeups. In rare
6152 // circumstances this can cause a thread to return prematurely from
6153 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
6154 // simply re-test the condition and re-park itself.
6155 }
6158 // JSR166
6159 // -------------------------------------------------------
6161 /*
6162 * The solaris and linux implementations of park/unpark are fairly
6163 * conservative for now, but can be improved. They currently use a
6164 * mutex/condvar pair, plus a a count.
6165 * Park decrements count if > 0, else does a condvar wait. Unpark
6166 * sets count to 1 and signals condvar. Only one thread ever waits
6167 * on the condvar. Contention seen when trying to park implies that someone
6168 * is unparking you, so don't wait. And spurious returns are fine, so there
6169 * is no need to track notifications.
6170 */
6172 /*
6173 * This code is common to linux and solaris and will be moved to a
6174 * common place in dolphin.
6175 *
6176 * The passed in time value is either a relative time in nanoseconds
6177 * or an absolute time in milliseconds. Either way it has to be unpacked
6178 * into suitable seconds and nanoseconds components and stored in the
6179 * given timespec structure.
6180 * Given time is a 64-bit value and the time_t used in the timespec is only
6181 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
6182 * overflow if times way in the future are given. Further on Solaris versions
6183 * prior to 10 there is a restriction (see cond_timedwait) that the specified
6184 * number of seconds, in abstime, is less than current_time + 100,000,000.
6185 * As it will be 28 years before "now + 100000000" will overflow we can
6186 * ignore overflow and just impose a hard-limit on seconds using the value
6187 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
6188 * years from "now".
6189 */
6191 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
6192 assert (time > 0, "convertTime");
6193 time_t max_secs = 0;
6195 if (!os::Linux::supports_monotonic_clock() || isAbsolute) {
6196 struct timeval now;
6197 int status = gettimeofday(&now, NULL);
6198 assert(status == 0, "gettimeofday");
6200 max_secs = now.tv_sec + MAX_SECS;
6202 if (isAbsolute) {
6203 jlong secs = time / 1000;
6204 if (secs > max_secs) {
6205 absTime->tv_sec = max_secs;
6206 } else {
6207 absTime->tv_sec = secs;
6208 }
6209 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
6210 } else {
6211 jlong secs = time / NANOSECS_PER_SEC;
6212 if (secs >= MAX_SECS) {
6213 absTime->tv_sec = max_secs;
6214 absTime->tv_nsec = 0;
6215 } else {
6216 absTime->tv_sec = now.tv_sec + secs;
6217 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
6218 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6219 absTime->tv_nsec -= NANOSECS_PER_SEC;
6220 ++absTime->tv_sec; // note: this must be <= max_secs
6221 }
6222 }
6223 }
6224 } else {
6225 // must be relative using monotonic clock
6226 struct timespec now;
6227 int status = os::Linux::clock_gettime(CLOCK_MONOTONIC, &now);
6228 assert_status(status == 0, status, "clock_gettime");
6229 max_secs = now.tv_sec + MAX_SECS;
6230 jlong secs = time / NANOSECS_PER_SEC;
6231 if (secs >= MAX_SECS) {
6232 absTime->tv_sec = max_secs;
6233 absTime->tv_nsec = 0;
6234 } else {
6235 absTime->tv_sec = now.tv_sec + secs;
6236 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_nsec;
6237 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
6238 absTime->tv_nsec -= NANOSECS_PER_SEC;
6239 ++absTime->tv_sec; // note: this must be <= max_secs
6240 }
6241 }
6242 }
6243 assert(absTime->tv_sec >= 0, "tv_sec < 0");
6244 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
6245 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
6246 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
6247 }
6249 void Parker::park(bool isAbsolute, jlong time) {
6250 // Ideally we'd do something useful while spinning, such
6251 // as calling unpackTime().
6253 // Optional fast-path check:
6254 // Return immediately if a permit is available.
6255 // We depend on Atomic::xchg() having full barrier semantics
6256 // since we are doing a lock-free update to _counter.
6257 if (Atomic::xchg(0, &_counter) > 0) return;
6259 Thread* thread = Thread::current();
6260 assert(thread->is_Java_thread(), "Must be JavaThread");
6261 JavaThread *jt = (JavaThread *)thread;
6263 // Optional optimization -- avoid state transitions if there's an interrupt pending.
6264 // Check interrupt before trying to wait
6265 if (Thread::is_interrupted(thread, false)) {
6266 return;
6267 }
6269 // Next, demultiplex/decode time arguments
6270 timespec absTime;
6271 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
6272 return;
6273 }
6274 if (time > 0) {
6275 unpackTime(&absTime, isAbsolute, time);
6276 }
6279 // Enter safepoint region
6280 // Beware of deadlocks such as 6317397.
6281 // The per-thread Parker:: mutex is a classic leaf-lock.
6282 // In particular a thread must never block on the Threads_lock while
6283 // holding the Parker:: mutex. If safepoints are pending both the
6284 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
6285 ThreadBlockInVM tbivm(jt);
6287 // Don't wait if cannot get lock since interference arises from
6288 // unblocking. Also. check interrupt before trying wait
6289 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
6290 return;
6291 }
6293 int status ;
6294 if (_counter > 0) { // no wait needed
6295 _counter = 0;
6296 status = pthread_mutex_unlock(_mutex);
6297 assert (status == 0, "invariant") ;
6298 // Paranoia to ensure our locked and lock-free paths interact
6299 // correctly with each other and Java-level accesses.
6300 OrderAccess::fence();
6301 return;
6302 }
6304 #ifdef ASSERT
6305 // Don't catch signals while blocked; let the running threads have the signals.
6306 // (This allows a debugger to break into the running thread.)
6307 sigset_t oldsigs;
6308 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
6309 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
6310 #endif
6312 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
6313 jt->set_suspend_equivalent();
6314 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
6316 assert(_cur_index == -1, "invariant");
6317 if (time == 0) {
6318 _cur_index = REL_INDEX; // arbitrary choice when not timed
6319 status = pthread_cond_wait (&_cond[_cur_index], _mutex) ;
6320 } else {
6321 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
6322 status = os::Linux::safe_cond_timedwait (&_cond[_cur_index], _mutex, &absTime) ;
6323 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
6324 pthread_cond_destroy (&_cond[_cur_index]) ;
6325 pthread_cond_init (&_cond[_cur_index], isAbsolute ? NULL : os::Linux::condAttr());
6326 }
6327 }
6328 _cur_index = -1;
6329 assert_status(status == 0 || status == EINTR ||
6330 status == ETIME || status == ETIMEDOUT,
6331 status, "cond_timedwait");
6333 #ifdef ASSERT
6334 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
6335 #endif
6337 _counter = 0 ;
6338 status = pthread_mutex_unlock(_mutex) ;
6339 assert_status(status == 0, status, "invariant") ;
6340 // Paranoia to ensure our locked and lock-free paths interact
6341 // correctly with each other and Java-level accesses.
6342 OrderAccess::fence();
6344 // If externally suspended while waiting, re-suspend
6345 if (jt->handle_special_suspend_equivalent_condition()) {
6346 jt->java_suspend_self();
6347 }
6348 }
6350 void Parker::unpark() {
6351 int s, status ;
6352 status = pthread_mutex_lock(_mutex);
6353 assert (status == 0, "invariant") ;
6354 s = _counter;
6355 _counter = 1;
6356 if (s < 1) {
6357 // thread might be parked
6358 if (_cur_index != -1) {
6359 // thread is definitely parked
6360 if (WorkAroundNPTLTimedWaitHang) {
6361 status = pthread_cond_signal (&_cond[_cur_index]);
6362 assert (status == 0, "invariant");
6363 status = pthread_mutex_unlock(_mutex);
6364 assert (status == 0, "invariant");
6365 } else {
6366 // must capture correct index before unlocking
6367 int index = _cur_index;
6368 status = pthread_mutex_unlock(_mutex);
6369 assert (status == 0, "invariant");
6370 status = pthread_cond_signal (&_cond[index]);
6371 assert (status == 0, "invariant");
6372 }
6373 } else {
6374 pthread_mutex_unlock(_mutex);
6375 assert (status == 0, "invariant") ;
6376 }
6377 } else {
6378 pthread_mutex_unlock(_mutex);
6379 assert (status == 0, "invariant") ;
6380 }
6381 }
6384 extern char** environ;
6386 // Run the specified command in a separate process. Return its exit value,
6387 // or -1 on failure (e.g. can't fork a new process).
6388 // Unlike system(), this function can be called from signal handler. It
6389 // doesn't block SIGINT et al.
6390 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
6391 const char * argv[4] = {"sh", "-c", cmd, NULL};
6393 pid_t pid ;
6395 if (use_vfork_if_available) {
6396 pid = vfork();
6397 } else {
6398 pid = fork();
6399 }
6401 if (pid < 0) {
6402 // fork failed
6403 return -1;
6405 } else if (pid == 0) {
6406 // child process
6408 execve("/bin/sh", (char* const*)argv, environ);
6410 // execve failed
6411 _exit(-1);
6413 } else {
6414 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
6415 // care about the actual exit code, for now.
6417 int status;
6419 // Wait for the child process to exit. This returns immediately if
6420 // the child has already exited. */
6421 while (waitpid(pid, &status, 0) < 0) {
6422 switch (errno) {
6423 case ECHILD: return 0;
6424 case EINTR: break;
6425 default: return -1;
6426 }
6427 }
6429 if (WIFEXITED(status)) {
6430 // The child exited normally; get its exit code.
6431 return WEXITSTATUS(status);
6432 } else if (WIFSIGNALED(status)) {
6433 // The child exited because of a signal
6434 // The best value to return is 0x80 + signal number,
6435 // because that is what all Unix shells do, and because
6436 // it allows callers to distinguish between process exit and
6437 // process death by signal.
6438 return 0x80 + WTERMSIG(status);
6439 } else {
6440 // Unknown exit code; pass it through
6441 return status;
6442 }
6443 }
6444 }
6446 // is_headless_jre()
6447 //
6448 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
6449 // in order to report if we are running in a headless jre
6450 //
6451 // Since JDK8 xawt/libmawt.so was moved into the same directory
6452 // as libawt.so, and renamed libawt_xawt.so
6453 //
6454 bool os::is_headless_jre() {
6455 struct stat statbuf;
6456 char buf[MAXPATHLEN];
6457 char libmawtpath[MAXPATHLEN];
6458 const char *xawtstr = "/xawt/libmawt.so";
6459 const char *new_xawtstr = "/libawt_xawt.so";
6460 char *p;
6462 // Get path to libjvm.so
6463 os::jvm_path(buf, sizeof(buf));
6465 // Get rid of libjvm.so
6466 p = strrchr(buf, '/');
6467 if (p == NULL) return false;
6468 else *p = '\0';
6470 // Get rid of client or server
6471 p = strrchr(buf, '/');
6472 if (p == NULL) return false;
6473 else *p = '\0';
6475 // check xawt/libmawt.so
6476 strcpy(libmawtpath, buf);
6477 strcat(libmawtpath, xawtstr);
6478 if (::stat(libmawtpath, &statbuf) == 0) return false;
6480 // check libawt_xawt.so
6481 strcpy(libmawtpath, buf);
6482 strcat(libmawtpath, new_xawtstr);
6483 if (::stat(libmawtpath, &statbuf) == 0) return false;
6485 return true;
6486 }
6488 // Get the default path to the core file
6489 // Returns the length of the string
6490 int os::get_core_path(char* buffer, size_t bufferSize) {
6491 const char* p = get_current_directory(buffer, bufferSize);
6493 if (p == NULL) {
6494 assert(p != NULL, "failed to get current directory");
6495 return 0;
6496 }
6498 return strlen(buffer);
6499 }
6501 /////////////// Unit tests ///////////////
6503 #ifndef PRODUCT
6505 #define test_log(...) \
6506 do {\
6507 if (VerboseInternalVMTests) { \
6508 tty->print_cr(__VA_ARGS__); \
6509 tty->flush(); \
6510 }\
6511 } while (false)
6513 class TestReserveMemorySpecial : AllStatic {
6514 public:
6515 static void small_page_write(void* addr, size_t size) {
6516 size_t page_size = os::vm_page_size();
6518 char* end = (char*)addr + size;
6519 for (char* p = (char*)addr; p < end; p += page_size) {
6520 *p = 1;
6521 }
6522 }
6524 static void test_reserve_memory_special_huge_tlbfs_only(size_t size) {
6525 if (!UseHugeTLBFS) {
6526 return;
6527 }
6529 test_log("test_reserve_memory_special_huge_tlbfs_only(" SIZE_FORMAT ")", size);
6531 char* addr = os::Linux::reserve_memory_special_huge_tlbfs_only(size, NULL, false);
6533 if (addr != NULL) {
6534 small_page_write(addr, size);
6536 os::Linux::release_memory_special_huge_tlbfs(addr, size);
6537 }
6538 }
6540 static void test_reserve_memory_special_huge_tlbfs_only() {
6541 if (!UseHugeTLBFS) {
6542 return;
6543 }
6545 size_t lp = os::large_page_size();
6547 for (size_t size = lp; size <= lp * 10; size += lp) {
6548 test_reserve_memory_special_huge_tlbfs_only(size);
6549 }
6550 }
6552 static void test_reserve_memory_special_huge_tlbfs_mixed() {
6553 size_t lp = os::large_page_size();
6554 size_t ag = os::vm_allocation_granularity();
6556 // sizes to test
6557 const size_t sizes[] = {
6558 lp, lp + ag, lp + lp / 2, lp * 2,
6559 lp * 2 + ag, lp * 2 - ag, lp * 2 + lp / 2,
6560 lp * 10, lp * 10 + lp / 2
6561 };
6562 const int num_sizes = sizeof(sizes) / sizeof(size_t);
6564 // For each size/alignment combination, we test three scenarios:
6565 // 1) with req_addr == NULL
6566 // 2) with a non-null req_addr at which we expect to successfully allocate
6567 // 3) with a non-null req_addr which contains a pre-existing mapping, at which we
6568 // expect the allocation to either fail or to ignore req_addr
6570 // Pre-allocate two areas; they shall be as large as the largest allocation
6571 // and aligned to the largest alignment we will be testing.
6572 const size_t mapping_size = sizes[num_sizes - 1] * 2;
6573 char* const mapping1 = (char*) ::mmap(NULL, mapping_size,
6574 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6575 -1, 0);
6576 assert(mapping1 != MAP_FAILED, "should work");
6578 char* const mapping2 = (char*) ::mmap(NULL, mapping_size,
6579 PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE,
6580 -1, 0);
6581 assert(mapping2 != MAP_FAILED, "should work");
6583 // Unmap the first mapping, but leave the second mapping intact: the first
6584 // mapping will serve as a value for a "good" req_addr (case 2). The second
6585 // mapping, still intact, as "bad" req_addr (case 3).
6586 ::munmap(mapping1, mapping_size);
6588 // Case 1
6589 test_log("%s, req_addr NULL:", __FUNCTION__);
6590 test_log("size align result");
6592 for (int i = 0; i < num_sizes; i++) {
6593 const size_t size = sizes[i];
6594 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6595 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, NULL, false);
6596 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " -> " PTR_FORMAT " %s",
6597 size, alignment, p, (p != NULL ? "" : "(failed)"));
6598 if (p != NULL) {
6599 assert(is_ptr_aligned(p, alignment), "must be");
6600 small_page_write(p, size);
6601 os::Linux::release_memory_special_huge_tlbfs(p, size);
6602 }
6603 }
6604 }
6606 // Case 2
6607 test_log("%s, req_addr non-NULL:", __FUNCTION__);
6608 test_log("size align req_addr result");
6610 for (int i = 0; i < num_sizes; i++) {
6611 const size_t size = sizes[i];
6612 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6613 char* const req_addr = (char*) align_ptr_up(mapping1, alignment);
6614 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6615 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6616 size, alignment, req_addr, p,
6617 ((p != NULL ? (p == req_addr ? "(exact match)" : "") : "(failed)")));
6618 if (p != NULL) {
6619 assert(p == req_addr, "must be");
6620 small_page_write(p, size);
6621 os::Linux::release_memory_special_huge_tlbfs(p, size);
6622 }
6623 }
6624 }
6626 // Case 3
6627 test_log("%s, req_addr non-NULL with preexisting mapping:", __FUNCTION__);
6628 test_log("size align req_addr result");
6630 for (int i = 0; i < num_sizes; i++) {
6631 const size_t size = sizes[i];
6632 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6633 char* const req_addr = (char*) align_ptr_up(mapping2, alignment);
6634 char* p = os::Linux::reserve_memory_special_huge_tlbfs_mixed(size, alignment, req_addr, false);
6635 test_log(SIZE_FORMAT_HEX " " SIZE_FORMAT_HEX " " PTR_FORMAT " -> " PTR_FORMAT " %s",
6636 size, alignment, req_addr, p,
6637 ((p != NULL ? "" : "(failed)")));
6638 // as the area around req_addr contains already existing mappings, the API should always
6639 // return NULL (as per contract, it cannot return another address)
6640 assert(p == NULL, "must be");
6641 }
6642 }
6644 ::munmap(mapping2, mapping_size);
6646 }
6648 static void test_reserve_memory_special_huge_tlbfs() {
6649 if (!UseHugeTLBFS) {
6650 return;
6651 }
6653 test_reserve_memory_special_huge_tlbfs_only();
6654 test_reserve_memory_special_huge_tlbfs_mixed();
6655 }
6657 static void test_reserve_memory_special_shm(size_t size, size_t alignment) {
6658 if (!UseSHM) {
6659 return;
6660 }
6662 test_log("test_reserve_memory_special_shm(" SIZE_FORMAT ", " SIZE_FORMAT ")", size, alignment);
6664 char* addr = os::Linux::reserve_memory_special_shm(size, alignment, NULL, false);
6666 if (addr != NULL) {
6667 assert(is_ptr_aligned(addr, alignment), "Check");
6668 assert(is_ptr_aligned(addr, os::large_page_size()), "Check");
6670 small_page_write(addr, size);
6672 os::Linux::release_memory_special_shm(addr, size);
6673 }
6674 }
6676 static void test_reserve_memory_special_shm() {
6677 size_t lp = os::large_page_size();
6678 size_t ag = os::vm_allocation_granularity();
6680 for (size_t size = ag; size < lp * 3; size += ag) {
6681 for (size_t alignment = ag; is_size_aligned(size, alignment); alignment *= 2) {
6682 test_reserve_memory_special_shm(size, alignment);
6683 }
6684 }
6685 }
6687 static void test() {
6688 test_reserve_memory_special_huge_tlbfs();
6689 test_reserve_memory_special_shm();
6690 }
6691 };
6693 void TestReserveMemorySpecial_test() {
6694 TestReserveMemorySpecial::test();
6695 }
6697 #endif