Thu, 04 Oct 2012 06:31:07 -0700
8000102: Resolve include conflicts
Summary: Removing include of c1/c1_runtime.hpp and opto/runtime.hpp from all os-files.
Reviewed-by: kvn
Contributed-by: nils.eliasson@oracle.com
1 /*
2 * Copyright (c) 1999, 2012, 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 "interpreter/interpreter.hpp"
33 #include "jvm_linux.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/filemap.hpp"
36 #include "mutex_linux.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "os_share_linux.hpp"
39 #include "prims/jniFastGetField.hpp"
40 #include "prims/jvm.h"
41 #include "prims/jvm_misc.hpp"
42 #include "runtime/arguments.hpp"
43 #include "runtime/extendedPC.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.hpp"
46 #include "runtime/java.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/mutexLocker.hpp"
49 #include "runtime/objectMonitor.hpp"
50 #include "runtime/osThread.hpp"
51 #include "runtime/perfMemory.hpp"
52 #include "runtime/sharedRuntime.hpp"
53 #include "runtime/statSampler.hpp"
54 #include "runtime/stubRoutines.hpp"
55 #include "runtime/threadCritical.hpp"
56 #include "runtime/timer.hpp"
57 #include "services/attachListener.hpp"
58 #include "services/runtimeService.hpp"
59 #include "thread_linux.inline.hpp"
60 #include "utilities/decoder.hpp"
61 #include "utilities/defaultStream.hpp"
62 #include "utilities/events.hpp"
63 #include "utilities/growableArray.hpp"
64 #include "utilities/vmError.hpp"
65 #ifdef TARGET_ARCH_x86
66 # include "assembler_x86.inline.hpp"
67 # include "nativeInst_x86.hpp"
68 #endif
69 #ifdef TARGET_ARCH_sparc
70 # include "assembler_sparc.inline.hpp"
71 # include "nativeInst_sparc.hpp"
72 #endif
73 #ifdef TARGET_ARCH_zero
74 # include "assembler_zero.inline.hpp"
75 # include "nativeInst_zero.hpp"
76 #endif
77 #ifdef TARGET_ARCH_arm
78 # include "assembler_arm.inline.hpp"
79 # include "nativeInst_arm.hpp"
80 #endif
81 #ifdef TARGET_ARCH_ppc
82 # include "assembler_ppc.inline.hpp"
83 # include "nativeInst_ppc.hpp"
84 #endif
86 // put OS-includes here
87 # include <sys/types.h>
88 # include <sys/mman.h>
89 # include <sys/stat.h>
90 # include <sys/select.h>
91 # include <pthread.h>
92 # include <signal.h>
93 # include <errno.h>
94 # include <dlfcn.h>
95 # include <stdio.h>
96 # include <unistd.h>
97 # include <sys/resource.h>
98 # include <pthread.h>
99 # include <sys/stat.h>
100 # include <sys/time.h>
101 # include <sys/times.h>
102 # include <sys/utsname.h>
103 # include <sys/socket.h>
104 # include <sys/wait.h>
105 # include <pwd.h>
106 # include <poll.h>
107 # include <semaphore.h>
108 # include <fcntl.h>
109 # include <string.h>
110 # include <syscall.h>
111 # include <sys/sysinfo.h>
112 # include <gnu/libc-version.h>
113 # include <sys/ipc.h>
114 # include <sys/shm.h>
115 # include <link.h>
116 # include <stdint.h>
117 # include <inttypes.h>
118 # include <sys/ioctl.h>
120 #define MAX_PATH (2 * K)
122 // for timer info max values which include all bits
123 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
125 #define LARGEPAGES_BIT (1 << 6)
126 ////////////////////////////////////////////////////////////////////////////////
127 // global variables
128 julong os::Linux::_physical_memory = 0;
130 address os::Linux::_initial_thread_stack_bottom = NULL;
131 uintptr_t os::Linux::_initial_thread_stack_size = 0;
133 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
134 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
135 Mutex* os::Linux::_createThread_lock = NULL;
136 pthread_t os::Linux::_main_thread;
137 int os::Linux::_page_size = -1;
138 bool os::Linux::_is_floating_stack = false;
139 bool os::Linux::_is_NPTL = false;
140 bool os::Linux::_supports_fast_thread_cpu_time = false;
141 const char * os::Linux::_glibc_version = NULL;
142 const char * os::Linux::_libpthread_version = NULL;
144 static jlong initial_time_count=0;
146 static int clock_tics_per_sec = 100;
148 // For diagnostics to print a message once. see run_periodic_checks
149 static sigset_t check_signal_done;
150 static bool check_signals = true;;
152 static pid_t _initial_pid = 0;
154 /* Signal number used to suspend/resume a thread */
156 /* do not use any signal number less than SIGSEGV, see 4355769 */
157 static int SR_signum = SIGUSR2;
158 sigset_t SR_sigset;
160 /* Used to protect dlsym() calls */
161 static pthread_mutex_t dl_mutex;
163 #ifdef JAVASE_EMBEDDED
164 class MemNotifyThread: public Thread {
165 friend class VMStructs;
166 public:
167 virtual void run();
169 private:
170 static MemNotifyThread* _memnotify_thread;
171 int _fd;
173 public:
175 // Constructor
176 MemNotifyThread(int fd);
178 // Tester
179 bool is_memnotify_thread() const { return true; }
181 // Printing
182 char* name() const { return (char*)"Linux MemNotify Thread"; }
184 // Returns the single instance of the MemNotifyThread
185 static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
187 // Create and start the single instance of MemNotifyThread
188 static void start();
189 };
190 #endif // JAVASE_EMBEDDED
192 // utility functions
194 static int SR_initialize();
195 static int SR_finalize();
197 julong os::available_memory() {
198 return Linux::available_memory();
199 }
201 julong os::Linux::available_memory() {
202 // values in struct sysinfo are "unsigned long"
203 struct sysinfo si;
204 sysinfo(&si);
206 return (julong)si.freeram * si.mem_unit;
207 }
209 julong os::physical_memory() {
210 return Linux::physical_memory();
211 }
213 julong os::allocatable_physical_memory(julong size) {
214 #ifdef _LP64
215 return size;
216 #else
217 julong result = MIN2(size, (julong)3800*M);
218 if (!is_allocatable(result)) {
219 // See comments under solaris for alignment considerations
220 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
221 result = MIN2(size, reasonable_size);
222 }
223 return result;
224 #endif // _LP64
225 }
227 ////////////////////////////////////////////////////////////////////////////////
228 // environment support
230 bool os::getenv(const char* name, char* buf, int len) {
231 const char* val = ::getenv(name);
232 if (val != NULL && strlen(val) < (size_t)len) {
233 strcpy(buf, val);
234 return true;
235 }
236 if (len > 0) buf[0] = 0; // return a null string
237 return false;
238 }
241 // Return true if user is running as root.
243 bool os::have_special_privileges() {
244 static bool init = false;
245 static bool privileges = false;
246 if (!init) {
247 privileges = (getuid() != geteuid()) || (getgid() != getegid());
248 init = true;
249 }
250 return privileges;
251 }
254 #ifndef SYS_gettid
255 // i386: 224, ia64: 1105, amd64: 186, sparc 143
256 #ifdef __ia64__
257 #define SYS_gettid 1105
258 #elif __i386__
259 #define SYS_gettid 224
260 #elif __amd64__
261 #define SYS_gettid 186
262 #elif __sparc__
263 #define SYS_gettid 143
264 #else
265 #error define gettid for the arch
266 #endif
267 #endif
269 // Cpu architecture string
270 #if defined(ZERO)
271 static char cpu_arch[] = ZERO_LIBARCH;
272 #elif defined(IA64)
273 static char cpu_arch[] = "ia64";
274 #elif defined(IA32)
275 static char cpu_arch[] = "i386";
276 #elif defined(AMD64)
277 static char cpu_arch[] = "amd64";
278 #elif defined(ARM)
279 static char cpu_arch[] = "arm";
280 #elif defined(PPC)
281 static char cpu_arch[] = "ppc";
282 #elif defined(SPARC)
283 # ifdef _LP64
284 static char cpu_arch[] = "sparcv9";
285 # else
286 static char cpu_arch[] = "sparc";
287 # endif
288 #else
289 #error Add appropriate cpu_arch setting
290 #endif
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 // char arch[12];
339 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
341 // The next steps are taken in the product version:
342 //
343 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
344 // This library should be located at:
345 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
346 //
347 // If "/jre/lib/" appears at the right place in the path, then we
348 // assume libjvm[_g].so is installed in a JDK and we use this path.
349 //
350 // Otherwise exit with message: "Could not create the Java virtual machine."
351 //
352 // The following extra steps are taken in the debugging version:
353 //
354 // If "/jre/lib/" does NOT appear at the right place in the path
355 // instead of exit check for $JAVA_HOME environment variable.
356 //
357 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
358 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
359 // it looks like libjvm[_g].so is installed there
360 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
361 //
362 // Otherwise exit.
363 //
364 // Important note: if the location of libjvm.so changes this
365 // code needs to be changed accordingly.
367 // The next few definitions allow the code to be verbatim:
368 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n), mtInternal)
369 #define getenv(n) ::getenv(n)
371 /*
372 * See ld(1):
373 * The linker uses the following search paths to locate required
374 * shared libraries:
375 * 1: ...
376 * ...
377 * 7: The default directories, normally /lib and /usr/lib.
378 */
379 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
380 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
381 #else
382 #define DEFAULT_LIBPATH "/lib:/usr/lib"
383 #endif
385 #define EXTENSIONS_DIR "/lib/ext"
386 #define ENDORSED_DIR "/lib/endorsed"
387 #define REG_DIR "/usr/java/packages"
389 {
390 /* sysclasspath, java_home, dll_dir */
391 {
392 char *home_path;
393 char *dll_path;
394 char *pslash;
395 char buf[MAXPATHLEN];
396 os::jvm_path(buf, sizeof(buf));
398 // Found the full path to libjvm.so.
399 // Now cut the path to <java_home>/jre if we can.
400 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
401 pslash = strrchr(buf, '/');
402 if (pslash != NULL)
403 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
404 dll_path = malloc(strlen(buf) + 1);
405 if (dll_path == NULL)
406 return;
407 strcpy(dll_path, buf);
408 Arguments::set_dll_dir(dll_path);
410 if (pslash != NULL) {
411 pslash = strrchr(buf, '/');
412 if (pslash != NULL) {
413 *pslash = '\0'; /* get rid of /<arch> */
414 pslash = strrchr(buf, '/');
415 if (pslash != NULL)
416 *pslash = '\0'; /* get rid of /lib */
417 }
418 }
420 home_path = malloc(strlen(buf) + 1);
421 if (home_path == NULL)
422 return;
423 strcpy(home_path, buf);
424 Arguments::set_java_home(home_path);
426 if (!set_boot_path('/', ':'))
427 return;
428 }
430 /*
431 * Where to look for native libraries
432 *
433 * Note: Due to a legacy implementation, most of the library path
434 * is set in the launcher. This was to accomodate linking restrictions
435 * on legacy Linux implementations (which are no longer supported).
436 * Eventually, all the library path setting will be done here.
437 *
438 * However, to prevent the proliferation of improperly built native
439 * libraries, the new path component /usr/java/packages is added here.
440 * Eventually, all the library path setting will be done here.
441 */
442 {
443 char *ld_library_path;
445 /*
446 * Construct the invariant part of ld_library_path. Note that the
447 * space for the colon and the trailing null are provided by the
448 * nulls included by the sizeof operator (so actually we allocate
449 * a byte more than necessary).
450 */
451 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
452 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
453 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
455 /*
456 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
457 * should always exist (until the legacy problem cited above is
458 * addressed).
459 */
460 char *v = getenv("LD_LIBRARY_PATH");
461 if (v != NULL) {
462 char *t = ld_library_path;
463 /* That's +1 for the colon and +1 for the trailing '\0' */
464 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
465 sprintf(ld_library_path, "%s:%s", v, t);
466 }
467 Arguments::set_library_path(ld_library_path);
468 }
470 /*
471 * Extensions directories.
472 *
473 * Note that the space for the colon and the trailing null are provided
474 * by the nulls included by the sizeof operator (so actually one byte more
475 * than necessary is allocated).
476 */
477 {
478 char *buf = malloc(strlen(Arguments::get_java_home()) +
479 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
480 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
481 Arguments::get_java_home());
482 Arguments::set_ext_dirs(buf);
483 }
485 /* Endorsed standards default directory. */
486 {
487 char * buf;
488 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
489 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
490 Arguments::set_endorsed_dirs(buf);
491 }
492 }
494 #undef malloc
495 #undef getenv
496 #undef EXTENSIONS_DIR
497 #undef ENDORSED_DIR
499 // Done
500 return;
501 }
503 ////////////////////////////////////////////////////////////////////////////////
504 // breakpoint support
506 void os::breakpoint() {
507 BREAKPOINT;
508 }
510 extern "C" void breakpoint() {
511 // use debugger to set breakpoint here
512 }
514 ////////////////////////////////////////////////////////////////////////////////
515 // signal support
517 debug_only(static bool signal_sets_initialized = false);
518 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
520 bool os::Linux::is_sig_ignored(int sig) {
521 struct sigaction oact;
522 sigaction(sig, (struct sigaction*)NULL, &oact);
523 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
524 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
525 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
526 return true;
527 else
528 return false;
529 }
531 void os::Linux::signal_sets_init() {
532 // Should also have an assertion stating we are still single-threaded.
533 assert(!signal_sets_initialized, "Already initialized");
534 // Fill in signals that are necessarily unblocked for all threads in
535 // the VM. Currently, we unblock the following signals:
536 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
537 // by -Xrs (=ReduceSignalUsage));
538 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
539 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
540 // the dispositions or masks wrt these signals.
541 // Programs embedding the VM that want to use the above signals for their
542 // own purposes must, at this time, use the "-Xrs" option to prevent
543 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
544 // (See bug 4345157, and other related bugs).
545 // In reality, though, unblocking these signals is really a nop, since
546 // these signals are not blocked by default.
547 sigemptyset(&unblocked_sigs);
548 sigemptyset(&allowdebug_blocked_sigs);
549 sigaddset(&unblocked_sigs, SIGILL);
550 sigaddset(&unblocked_sigs, SIGSEGV);
551 sigaddset(&unblocked_sigs, SIGBUS);
552 sigaddset(&unblocked_sigs, SIGFPE);
553 sigaddset(&unblocked_sigs, SR_signum);
555 if (!ReduceSignalUsage) {
556 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
557 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
558 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
559 }
560 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
561 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
562 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
563 }
564 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
565 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
566 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
567 }
568 }
569 // Fill in signals that are blocked by all but the VM thread.
570 sigemptyset(&vm_sigs);
571 if (!ReduceSignalUsage)
572 sigaddset(&vm_sigs, BREAK_SIGNAL);
573 debug_only(signal_sets_initialized = true);
575 }
577 // These are signals that are unblocked while a thread is running Java.
578 // (For some reason, they get blocked by default.)
579 sigset_t* os::Linux::unblocked_signals() {
580 assert(signal_sets_initialized, "Not initialized");
581 return &unblocked_sigs;
582 }
584 // These are the signals that are blocked while a (non-VM) thread is
585 // running Java. Only the VM thread handles these signals.
586 sigset_t* os::Linux::vm_signals() {
587 assert(signal_sets_initialized, "Not initialized");
588 return &vm_sigs;
589 }
591 // These are signals that are blocked during cond_wait to allow debugger in
592 sigset_t* os::Linux::allowdebug_blocked_signals() {
593 assert(signal_sets_initialized, "Not initialized");
594 return &allowdebug_blocked_sigs;
595 }
597 void os::Linux::hotspot_sigmask(Thread* thread) {
599 //Save caller's signal mask before setting VM signal mask
600 sigset_t caller_sigmask;
601 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
603 OSThread* osthread = thread->osthread();
604 osthread->set_caller_sigmask(caller_sigmask);
606 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
608 if (!ReduceSignalUsage) {
609 if (thread->is_VM_thread()) {
610 // Only the VM thread handles BREAK_SIGNAL ...
611 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
612 } else {
613 // ... all other threads block BREAK_SIGNAL
614 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
615 }
616 }
617 }
619 //////////////////////////////////////////////////////////////////////////////
620 // detecting pthread library
622 void os::Linux::libpthread_init() {
623 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
624 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
625 // generic name for earlier versions.
626 // Define macros here so we can build HotSpot on old systems.
627 # ifndef _CS_GNU_LIBC_VERSION
628 # define _CS_GNU_LIBC_VERSION 2
629 # endif
630 # ifndef _CS_GNU_LIBPTHREAD_VERSION
631 # define _CS_GNU_LIBPTHREAD_VERSION 3
632 # endif
634 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
635 if (n > 0) {
636 char *str = (char *)malloc(n, mtInternal);
637 confstr(_CS_GNU_LIBC_VERSION, str, n);
638 os::Linux::set_glibc_version(str);
639 } else {
640 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
641 static char _gnu_libc_version[32];
642 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
643 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
644 os::Linux::set_glibc_version(_gnu_libc_version);
645 }
647 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
648 if (n > 0) {
649 char *str = (char *)malloc(n, mtInternal);
650 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
651 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
652 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
653 // is the case. LinuxThreads has a hard limit on max number of threads.
654 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
655 // On the other hand, NPTL does not have such a limit, sysconf()
656 // will return -1 and errno is not changed. Check if it is really NPTL.
657 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
658 strstr(str, "NPTL") &&
659 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
660 free(str);
661 os::Linux::set_libpthread_version("linuxthreads");
662 } else {
663 os::Linux::set_libpthread_version(str);
664 }
665 } else {
666 // glibc before 2.3.2 only has LinuxThreads.
667 os::Linux::set_libpthread_version("linuxthreads");
668 }
670 if (strstr(libpthread_version(), "NPTL")) {
671 os::Linux::set_is_NPTL();
672 } else {
673 os::Linux::set_is_LinuxThreads();
674 }
676 // LinuxThreads have two flavors: floating-stack mode, which allows variable
677 // stack size; and fixed-stack mode. NPTL is always floating-stack.
678 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
679 os::Linux::set_is_floating_stack();
680 }
681 }
683 /////////////////////////////////////////////////////////////////////////////
684 // thread stack
686 // Force Linux kernel to expand current thread stack. If "bottom" is close
687 // to the stack guard, caller should block all signals.
688 //
689 // MAP_GROWSDOWN:
690 // A special mmap() flag that is used to implement thread stacks. It tells
691 // kernel that the memory region should extend downwards when needed. This
692 // allows early versions of LinuxThreads to only mmap the first few pages
693 // when creating a new thread. Linux kernel will automatically expand thread
694 // stack as needed (on page faults).
695 //
696 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
697 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
698 // region, it's hard to tell if the fault is due to a legitimate stack
699 // access or because of reading/writing non-exist memory (e.g. buffer
700 // overrun). As a rule, if the fault happens below current stack pointer,
701 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
702 // application (see Linux kernel fault.c).
703 //
704 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
705 // stack overflow detection.
706 //
707 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
708 // not use this flag. However, the stack of initial thread is not created
709 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
710 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
711 // and then attach the thread to JVM.
712 //
713 // To get around the problem and allow stack banging on Linux, we need to
714 // manually expand thread stack after receiving the SIGSEGV.
715 //
716 // There are two ways to expand thread stack to address "bottom", we used
717 // both of them in JVM before 1.5:
718 // 1. adjust stack pointer first so that it is below "bottom", and then
719 // touch "bottom"
720 // 2. mmap() the page in question
721 //
722 // Now alternate signal stack is gone, it's harder to use 2. For instance,
723 // if current sp is already near the lower end of page 101, and we need to
724 // call mmap() to map page 100, it is possible that part of the mmap() frame
725 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
726 // That will destroy the mmap() frame and cause VM to crash.
727 //
728 // The following code works by adjusting sp first, then accessing the "bottom"
729 // page to force a page fault. Linux kernel will then automatically expand the
730 // stack mapping.
731 //
732 // _expand_stack_to() assumes its frame size is less than page size, which
733 // should always be true if the function is not inlined.
735 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
736 #define NOINLINE
737 #else
738 #define NOINLINE __attribute__ ((noinline))
739 #endif
741 static void _expand_stack_to(address bottom) NOINLINE;
743 static void _expand_stack_to(address bottom) {
744 address sp;
745 size_t size;
746 volatile char *p;
748 // Adjust bottom to point to the largest address within the same page, it
749 // gives us a one-page buffer if alloca() allocates slightly more memory.
750 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
751 bottom += os::Linux::page_size() - 1;
753 // sp might be slightly above current stack pointer; if that's the case, we
754 // will alloca() a little more space than necessary, which is OK. Don't use
755 // os::current_stack_pointer(), as its result can be slightly below current
756 // stack pointer, causing us to not alloca enough to reach "bottom".
757 sp = (address)&sp;
759 if (sp > bottom) {
760 size = sp - bottom;
761 p = (volatile char *)alloca(size);
762 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
763 p[0] = '\0';
764 }
765 }
767 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
768 assert(t!=NULL, "just checking");
769 assert(t->osthread()->expanding_stack(), "expand should be set");
770 assert(t->stack_base() != NULL, "stack_base was not initialized");
772 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
773 sigset_t mask_all, old_sigset;
774 sigfillset(&mask_all);
775 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
776 _expand_stack_to(addr);
777 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
778 return true;
779 }
780 return false;
781 }
783 //////////////////////////////////////////////////////////////////////////////
784 // create new thread
786 static address highest_vm_reserved_address();
788 // check if it's safe to start a new thread
789 static bool _thread_safety_check(Thread* thread) {
790 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
791 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
792 // Heap is mmap'ed at lower end of memory space. Thread stacks are
793 // allocated (MAP_FIXED) from high address space. Every thread stack
794 // occupies a fixed size slot (usually 2Mbytes, but user can change
795 // it to other values if they rebuild LinuxThreads).
796 //
797 // Problem with MAP_FIXED is that mmap() can still succeed even part of
798 // the memory region has already been mmap'ed. That means if we have too
799 // many threads and/or very large heap, eventually thread stack will
800 // collide with heap.
801 //
802 // Here we try to prevent heap/stack collision by comparing current
803 // stack bottom with the highest address that has been mmap'ed by JVM
804 // plus a safety margin for memory maps created by native code.
805 //
806 // This feature can be disabled by setting ThreadSafetyMargin to 0
807 //
808 if (ThreadSafetyMargin > 0) {
809 address stack_bottom = os::current_stack_base() - os::current_stack_size();
811 // not safe if our stack extends below the safety margin
812 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
813 } else {
814 return true;
815 }
816 } else {
817 // Floating stack LinuxThreads or NPTL:
818 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
819 // there's not enough space left, pthread_create() will fail. If we come
820 // here, that means enough space has been reserved for stack.
821 return true;
822 }
823 }
825 // Thread start routine for all newly created threads
826 static void *java_start(Thread *thread) {
827 // Try to randomize the cache line index of hot stack frames.
828 // This helps when threads of the same stack traces evict each other's
829 // cache lines. The threads can be either from the same JVM instance, or
830 // from different JVM instances. The benefit is especially true for
831 // processors with hyperthreading technology.
832 static int counter = 0;
833 int pid = os::current_process_id();
834 alloca(((pid ^ counter++) & 7) * 128);
836 ThreadLocalStorage::set_thread(thread);
838 OSThread* osthread = thread->osthread();
839 Monitor* sync = osthread->startThread_lock();
841 // non floating stack LinuxThreads needs extra check, see above
842 if (!_thread_safety_check(thread)) {
843 // notify parent thread
844 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
845 osthread->set_state(ZOMBIE);
846 sync->notify_all();
847 return NULL;
848 }
850 // thread_id is kernel thread id (similar to Solaris LWP id)
851 osthread->set_thread_id(os::Linux::gettid());
853 if (UseNUMA) {
854 int lgrp_id = os::numa_get_group_id();
855 if (lgrp_id != -1) {
856 thread->set_lgrp_id(lgrp_id);
857 }
858 }
859 // initialize signal mask for this thread
860 os::Linux::hotspot_sigmask(thread);
862 // initialize floating point control register
863 os::Linux::init_thread_fpu_state();
865 // handshaking with parent thread
866 {
867 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
869 // notify parent thread
870 osthread->set_state(INITIALIZED);
871 sync->notify_all();
873 // wait until os::start_thread()
874 while (osthread->get_state() == INITIALIZED) {
875 sync->wait(Mutex::_no_safepoint_check_flag);
876 }
877 }
879 // call one more level start routine
880 thread->run();
882 return 0;
883 }
885 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
886 assert(thread->osthread() == NULL, "caller responsible");
888 // Allocate the OSThread object
889 OSThread* osthread = new OSThread(NULL, NULL);
890 if (osthread == NULL) {
891 return false;
892 }
894 // set the correct thread state
895 osthread->set_thread_type(thr_type);
897 // Initial state is ALLOCATED but not INITIALIZED
898 osthread->set_state(ALLOCATED);
900 thread->set_osthread(osthread);
902 // init thread attributes
903 pthread_attr_t attr;
904 pthread_attr_init(&attr);
905 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
907 // stack size
908 if (os::Linux::supports_variable_stack_size()) {
909 // calculate stack size if it's not specified by caller
910 if (stack_size == 0) {
911 stack_size = os::Linux::default_stack_size(thr_type);
913 switch (thr_type) {
914 case os::java_thread:
915 // Java threads use ThreadStackSize which default value can be
916 // changed with the flag -Xss
917 assert (JavaThread::stack_size_at_create() > 0, "this should be set");
918 stack_size = JavaThread::stack_size_at_create();
919 break;
920 case os::compiler_thread:
921 if (CompilerThreadStackSize > 0) {
922 stack_size = (size_t)(CompilerThreadStackSize * K);
923 break;
924 } // else fall through:
925 // use VMThreadStackSize if CompilerThreadStackSize is not defined
926 case os::vm_thread:
927 case os::pgc_thread:
928 case os::cgc_thread:
929 case os::watcher_thread:
930 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
931 break;
932 }
933 }
935 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
936 pthread_attr_setstacksize(&attr, stack_size);
937 } else {
938 // let pthread_create() pick the default value.
939 }
941 // glibc guard page
942 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
944 ThreadState state;
946 {
947 // Serialize thread creation if we are running with fixed stack LinuxThreads
948 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
949 if (lock) {
950 os::Linux::createThread_lock()->lock_without_safepoint_check();
951 }
953 pthread_t tid;
954 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
956 pthread_attr_destroy(&attr);
958 if (ret != 0) {
959 if (PrintMiscellaneous && (Verbose || WizardMode)) {
960 perror("pthread_create()");
961 }
962 // Need to clean up stuff we've allocated so far
963 thread->set_osthread(NULL);
964 delete osthread;
965 if (lock) os::Linux::createThread_lock()->unlock();
966 return false;
967 }
969 // Store pthread info into the OSThread
970 osthread->set_pthread_id(tid);
972 // Wait until child thread is either initialized or aborted
973 {
974 Monitor* sync_with_child = osthread->startThread_lock();
975 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
976 while ((state = osthread->get_state()) == ALLOCATED) {
977 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
978 }
979 }
981 if (lock) {
982 os::Linux::createThread_lock()->unlock();
983 }
984 }
986 // Aborted due to thread limit being reached
987 if (state == ZOMBIE) {
988 thread->set_osthread(NULL);
989 delete osthread;
990 return false;
991 }
993 // The thread is returned suspended (in state INITIALIZED),
994 // and is started higher up in the call chain
995 assert(state == INITIALIZED, "race condition");
996 return true;
997 }
999 /////////////////////////////////////////////////////////////////////////////
1000 // attach existing thread
1002 // bootstrap the main thread
1003 bool os::create_main_thread(JavaThread* thread) {
1004 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
1005 return create_attached_thread(thread);
1006 }
1008 bool os::create_attached_thread(JavaThread* thread) {
1009 #ifdef ASSERT
1010 thread->verify_not_published();
1011 #endif
1013 // Allocate the OSThread object
1014 OSThread* osthread = new OSThread(NULL, NULL);
1016 if (osthread == NULL) {
1017 return false;
1018 }
1020 // Store pthread info into the OSThread
1021 osthread->set_thread_id(os::Linux::gettid());
1022 osthread->set_pthread_id(::pthread_self());
1024 // initialize floating point control register
1025 os::Linux::init_thread_fpu_state();
1027 // Initial thread state is RUNNABLE
1028 osthread->set_state(RUNNABLE);
1030 thread->set_osthread(osthread);
1032 if (UseNUMA) {
1033 int lgrp_id = os::numa_get_group_id();
1034 if (lgrp_id != -1) {
1035 thread->set_lgrp_id(lgrp_id);
1036 }
1037 }
1039 if (os::Linux::is_initial_thread()) {
1040 // If current thread is initial thread, its stack is mapped on demand,
1041 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
1042 // the entire stack region to avoid SEGV in stack banging.
1043 // It is also useful to get around the heap-stack-gap problem on SuSE
1044 // kernel (see 4821821 for details). We first expand stack to the top
1045 // of yellow zone, then enable stack yellow zone (order is significant,
1046 // enabling yellow zone first will crash JVM on SuSE Linux), so there
1047 // is no gap between the last two virtual memory regions.
1049 JavaThread *jt = (JavaThread *)thread;
1050 address addr = jt->stack_yellow_zone_base();
1051 assert(addr != NULL, "initialization problem?");
1052 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
1054 osthread->set_expanding_stack();
1055 os::Linux::manually_expand_stack(jt, addr);
1056 osthread->clear_expanding_stack();
1057 }
1059 // initialize signal mask for this thread
1060 // and save the caller's signal mask
1061 os::Linux::hotspot_sigmask(thread);
1063 return true;
1064 }
1066 void os::pd_start_thread(Thread* thread) {
1067 OSThread * osthread = thread->osthread();
1068 assert(osthread->get_state() != INITIALIZED, "just checking");
1069 Monitor* sync_with_child = osthread->startThread_lock();
1070 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
1071 sync_with_child->notify();
1072 }
1074 // Free Linux resources related to the OSThread
1075 void os::free_thread(OSThread* osthread) {
1076 assert(osthread != NULL, "osthread not set");
1078 if (Thread::current()->osthread() == osthread) {
1079 // Restore caller's signal mask
1080 sigset_t sigmask = osthread->caller_sigmask();
1081 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
1082 }
1084 delete osthread;
1085 }
1087 //////////////////////////////////////////////////////////////////////////////
1088 // thread local storage
1090 int os::allocate_thread_local_storage() {
1091 pthread_key_t key;
1092 int rslt = pthread_key_create(&key, NULL);
1093 assert(rslt == 0, "cannot allocate thread local storage");
1094 return (int)key;
1095 }
1097 // Note: This is currently not used by VM, as we don't destroy TLS key
1098 // on VM exit.
1099 void os::free_thread_local_storage(int index) {
1100 int rslt = pthread_key_delete((pthread_key_t)index);
1101 assert(rslt == 0, "invalid index");
1102 }
1104 void os::thread_local_storage_at_put(int index, void* value) {
1105 int rslt = pthread_setspecific((pthread_key_t)index, value);
1106 assert(rslt == 0, "pthread_setspecific failed");
1107 }
1109 extern "C" Thread* get_thread() {
1110 return ThreadLocalStorage::thread();
1111 }
1113 //////////////////////////////////////////////////////////////////////////////
1114 // initial thread
1116 // Check if current thread is the initial thread, similar to Solaris thr_main.
1117 bool os::Linux::is_initial_thread(void) {
1118 char dummy;
1119 // If called before init complete, thread stack bottom will be null.
1120 // Can be called if fatal error occurs before initialization.
1121 if (initial_thread_stack_bottom() == NULL) return false;
1122 assert(initial_thread_stack_bottom() != NULL &&
1123 initial_thread_stack_size() != 0,
1124 "os::init did not locate initial thread's stack region");
1125 if ((address)&dummy >= initial_thread_stack_bottom() &&
1126 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1127 return true;
1128 else return false;
1129 }
1131 // Find the virtual memory area that contains addr
1132 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1133 FILE *fp = fopen("/proc/self/maps", "r");
1134 if (fp) {
1135 address low, high;
1136 while (!feof(fp)) {
1137 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1138 if (low <= addr && addr < high) {
1139 if (vma_low) *vma_low = low;
1140 if (vma_high) *vma_high = high;
1141 fclose (fp);
1142 return true;
1143 }
1144 }
1145 for (;;) {
1146 int ch = fgetc(fp);
1147 if (ch == EOF || ch == (int)'\n') break;
1148 }
1149 }
1150 fclose(fp);
1151 }
1152 return false;
1153 }
1155 // Locate initial thread stack. This special handling of initial thread stack
1156 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1157 // bogus value for initial thread.
1158 void os::Linux::capture_initial_stack(size_t max_size) {
1159 // stack size is the easy part, get it from RLIMIT_STACK
1160 size_t stack_size;
1161 struct rlimit rlim;
1162 getrlimit(RLIMIT_STACK, &rlim);
1163 stack_size = rlim.rlim_cur;
1165 // 6308388: a bug in ld.so will relocate its own .data section to the
1166 // lower end of primordial stack; reduce ulimit -s value a little bit
1167 // so we won't install guard page on ld.so's data section.
1168 stack_size -= 2 * page_size();
1170 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1171 // 7.1, in both cases we will get 2G in return value.
1172 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1173 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1174 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1175 // in case other parts in glibc still assumes 2M max stack size.
1176 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1177 #ifndef IA64
1178 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1179 #else
1180 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1181 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1182 #endif
1184 // Try to figure out where the stack base (top) is. This is harder.
1185 //
1186 // When an application is started, glibc saves the initial stack pointer in
1187 // a global variable "__libc_stack_end", which is then used by system
1188 // libraries. __libc_stack_end should be pretty close to stack top. The
1189 // variable is available since the very early days. However, because it is
1190 // a private interface, it could disappear in the future.
1191 //
1192 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1193 // to __libc_stack_end, it is very close to stack top, but isn't the real
1194 // stack top. Note that /proc may not exist if VM is running as a chroot
1195 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1196 // /proc/<pid>/stat could change in the future (though unlikely).
1197 //
1198 // We try __libc_stack_end first. If that doesn't work, look for
1199 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1200 // as a hint, which should work well in most cases.
1202 uintptr_t stack_start;
1204 // try __libc_stack_end first
1205 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1206 if (p && *p) {
1207 stack_start = *p;
1208 } else {
1209 // see if we can get the start_stack field from /proc/self/stat
1210 FILE *fp;
1211 int pid;
1212 char state;
1213 int ppid;
1214 int pgrp;
1215 int session;
1216 int nr;
1217 int tpgrp;
1218 unsigned long flags;
1219 unsigned long minflt;
1220 unsigned long cminflt;
1221 unsigned long majflt;
1222 unsigned long cmajflt;
1223 unsigned long utime;
1224 unsigned long stime;
1225 long cutime;
1226 long cstime;
1227 long prio;
1228 long nice;
1229 long junk;
1230 long it_real;
1231 uintptr_t start;
1232 uintptr_t vsize;
1233 intptr_t rss;
1234 uintptr_t rsslim;
1235 uintptr_t scodes;
1236 uintptr_t ecode;
1237 int i;
1239 // Figure what the primordial thread stack base is. Code is inspired
1240 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1241 // followed by command name surrounded by parentheses, state, etc.
1242 char stat[2048];
1243 int statlen;
1245 fp = fopen("/proc/self/stat", "r");
1246 if (fp) {
1247 statlen = fread(stat, 1, 2047, fp);
1248 stat[statlen] = '\0';
1249 fclose(fp);
1251 // Skip pid and the command string. Note that we could be dealing with
1252 // weird command names, e.g. user could decide to rename java launcher
1253 // to "java 1.4.2 :)", then the stat file would look like
1254 // 1234 (java 1.4.2 :)) R ... ...
1255 // We don't really need to know the command string, just find the last
1256 // occurrence of ")" and then start parsing from there. See bug 4726580.
1257 char * s = strrchr(stat, ')');
1259 i = 0;
1260 if (s) {
1261 // Skip blank chars
1262 do s++; while (isspace(*s));
1264 #define _UFM UINTX_FORMAT
1265 #define _DFM INTX_FORMAT
1267 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1268 /* 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 */
1269 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,
1270 &state, /* 3 %c */
1271 &ppid, /* 4 %d */
1272 &pgrp, /* 5 %d */
1273 &session, /* 6 %d */
1274 &nr, /* 7 %d */
1275 &tpgrp, /* 8 %d */
1276 &flags, /* 9 %lu */
1277 &minflt, /* 10 %lu */
1278 &cminflt, /* 11 %lu */
1279 &majflt, /* 12 %lu */
1280 &cmajflt, /* 13 %lu */
1281 &utime, /* 14 %lu */
1282 &stime, /* 15 %lu */
1283 &cutime, /* 16 %ld */
1284 &cstime, /* 17 %ld */
1285 &prio, /* 18 %ld */
1286 &nice, /* 19 %ld */
1287 &junk, /* 20 %ld */
1288 &it_real, /* 21 %ld */
1289 &start, /* 22 UINTX_FORMAT */
1290 &vsize, /* 23 UINTX_FORMAT */
1291 &rss, /* 24 INTX_FORMAT */
1292 &rsslim, /* 25 UINTX_FORMAT */
1293 &scodes, /* 26 UINTX_FORMAT */
1294 &ecode, /* 27 UINTX_FORMAT */
1295 &stack_start); /* 28 UINTX_FORMAT */
1296 }
1298 #undef _UFM
1299 #undef _DFM
1301 if (i != 28 - 2) {
1302 assert(false, "Bad conversion from /proc/self/stat");
1303 // product mode - assume we are the initial thread, good luck in the
1304 // embedded case.
1305 warning("Can't detect initial thread stack location - bad conversion");
1306 stack_start = (uintptr_t) &rlim;
1307 }
1308 } else {
1309 // For some reason we can't open /proc/self/stat (for example, running on
1310 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1311 // most cases, so don't abort:
1312 warning("Can't detect initial thread stack location - no /proc/self/stat");
1313 stack_start = (uintptr_t) &rlim;
1314 }
1315 }
1317 // Now we have a pointer (stack_start) very close to the stack top, the
1318 // next thing to do is to figure out the exact location of stack top. We
1319 // can find out the virtual memory area that contains stack_start by
1320 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1321 // and its upper limit is the real stack top. (again, this would fail if
1322 // running inside chroot, because /proc may not exist.)
1324 uintptr_t stack_top;
1325 address low, high;
1326 if (find_vma((address)stack_start, &low, &high)) {
1327 // success, "high" is the true stack top. (ignore "low", because initial
1328 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1329 stack_top = (uintptr_t)high;
1330 } else {
1331 // failed, likely because /proc/self/maps does not exist
1332 warning("Can't detect initial thread stack location - find_vma failed");
1333 // best effort: stack_start is normally within a few pages below the real
1334 // stack top, use it as stack top, and reduce stack size so we won't put
1335 // guard page outside stack.
1336 stack_top = stack_start;
1337 stack_size -= 16 * page_size();
1338 }
1340 // stack_top could be partially down the page so align it
1341 stack_top = align_size_up(stack_top, page_size());
1343 if (max_size && stack_size > max_size) {
1344 _initial_thread_stack_size = max_size;
1345 } else {
1346 _initial_thread_stack_size = stack_size;
1347 }
1349 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1350 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1351 }
1353 ////////////////////////////////////////////////////////////////////////////////
1354 // time support
1356 // Time since start-up in seconds to a fine granularity.
1357 // Used by VMSelfDestructTimer and the MemProfiler.
1358 double os::elapsedTime() {
1360 return (double)(os::elapsed_counter()) * 0.000001;
1361 }
1363 jlong os::elapsed_counter() {
1364 timeval time;
1365 int status = gettimeofday(&time, NULL);
1366 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1367 }
1369 jlong os::elapsed_frequency() {
1370 return (1000 * 1000);
1371 }
1373 // For now, we say that linux does not support vtime. I have no idea
1374 // whether it can actually be made to (DLD, 9/13/05).
1376 bool os::supports_vtime() { return false; }
1377 bool os::enable_vtime() { return false; }
1378 bool os::vtime_enabled() { return false; }
1379 double os::elapsedVTime() {
1380 // better than nothing, but not much
1381 return elapsedTime();
1382 }
1384 jlong os::javaTimeMillis() {
1385 timeval time;
1386 int status = gettimeofday(&time, NULL);
1387 assert(status != -1, "linux error");
1388 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1389 }
1391 #ifndef CLOCK_MONOTONIC
1392 #define CLOCK_MONOTONIC (1)
1393 #endif
1395 void os::Linux::clock_init() {
1396 // we do dlopen's in this particular order due to bug in linux
1397 // dynamical loader (see 6348968) leading to crash on exit
1398 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1399 if (handle == NULL) {
1400 handle = dlopen("librt.so", RTLD_LAZY);
1401 }
1403 if (handle) {
1404 int (*clock_getres_func)(clockid_t, struct timespec*) =
1405 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1406 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1407 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1408 if (clock_getres_func && clock_gettime_func) {
1409 // See if monotonic clock is supported by the kernel. Note that some
1410 // early implementations simply return kernel jiffies (updated every
1411 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1412 // for nano time (though the monotonic property is still nice to have).
1413 // It's fixed in newer kernels, however clock_getres() still returns
1414 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1415 // resolution for now. Hopefully as people move to new kernels, this
1416 // won't be a problem.
1417 struct timespec res;
1418 struct timespec tp;
1419 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1420 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1421 // yes, monotonic clock is supported
1422 _clock_gettime = clock_gettime_func;
1423 } else {
1424 // close librt if there is no monotonic clock
1425 dlclose(handle);
1426 }
1427 }
1428 }
1429 }
1431 #ifndef SYS_clock_getres
1433 #if defined(IA32) || defined(AMD64)
1434 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1435 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1436 #else
1437 #warning "SYS_clock_getres not defined for this platform, disabling fast_thread_cpu_time"
1438 #define sys_clock_getres(x,y) -1
1439 #endif
1441 #else
1442 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1443 #endif
1445 void os::Linux::fast_thread_clock_init() {
1446 if (!UseLinuxPosixThreadCPUClocks) {
1447 return;
1448 }
1449 clockid_t clockid;
1450 struct timespec tp;
1451 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1452 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1454 // Switch to using fast clocks for thread cpu time if
1455 // the sys_clock_getres() returns 0 error code.
1456 // Note, that some kernels may support the current thread
1457 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1458 // returned by the pthread_getcpuclockid().
1459 // If the fast Posix clocks are supported then the sys_clock_getres()
1460 // must return at least tp.tv_sec == 0 which means a resolution
1461 // better than 1 sec. This is extra check for reliability.
1463 if(pthread_getcpuclockid_func &&
1464 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1465 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1467 _supports_fast_thread_cpu_time = true;
1468 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1469 }
1470 }
1472 jlong os::javaTimeNanos() {
1473 if (Linux::supports_monotonic_clock()) {
1474 struct timespec tp;
1475 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1476 assert(status == 0, "gettime error");
1477 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1478 return result;
1479 } else {
1480 timeval time;
1481 int status = gettimeofday(&time, NULL);
1482 assert(status != -1, "linux error");
1483 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1484 return 1000 * usecs;
1485 }
1486 }
1488 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1489 if (Linux::supports_monotonic_clock()) {
1490 info_ptr->max_value = ALL_64_BITS;
1492 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1493 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1494 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1495 } else {
1496 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1497 info_ptr->max_value = ALL_64_BITS;
1499 // gettimeofday is a real time clock so it skips
1500 info_ptr->may_skip_backward = true;
1501 info_ptr->may_skip_forward = true;
1502 }
1504 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1505 }
1507 // Return the real, user, and system times in seconds from an
1508 // arbitrary fixed point in the past.
1509 bool os::getTimesSecs(double* process_real_time,
1510 double* process_user_time,
1511 double* process_system_time) {
1512 struct tms ticks;
1513 clock_t real_ticks = times(&ticks);
1515 if (real_ticks == (clock_t) (-1)) {
1516 return false;
1517 } else {
1518 double ticks_per_second = (double) clock_tics_per_sec;
1519 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1520 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1521 *process_real_time = ((double) real_ticks) / ticks_per_second;
1523 return true;
1524 }
1525 }
1528 char * os::local_time_string(char *buf, size_t buflen) {
1529 struct tm t;
1530 time_t long_time;
1531 time(&long_time);
1532 localtime_r(&long_time, &t);
1533 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1534 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1535 t.tm_hour, t.tm_min, t.tm_sec);
1536 return buf;
1537 }
1539 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1540 return localtime_r(clock, res);
1541 }
1543 ////////////////////////////////////////////////////////////////////////////////
1544 // runtime exit support
1546 // Note: os::shutdown() might be called very early during initialization, or
1547 // called from signal handler. Before adding something to os::shutdown(), make
1548 // sure it is async-safe and can handle partially initialized VM.
1549 void os::shutdown() {
1551 // allow PerfMemory to attempt cleanup of any persistent resources
1552 perfMemory_exit();
1554 // needs to remove object in file system
1555 AttachListener::abort();
1557 // flush buffered output, finish log files
1558 ostream_abort();
1560 // Check for abort hook
1561 abort_hook_t abort_hook = Arguments::abort_hook();
1562 if (abort_hook != NULL) {
1563 abort_hook();
1564 }
1566 }
1568 // Note: os::abort() might be called very early during initialization, or
1569 // called from signal handler. Before adding something to os::abort(), make
1570 // sure it is async-safe and can handle partially initialized VM.
1571 void os::abort(bool dump_core) {
1572 os::shutdown();
1573 if (dump_core) {
1574 #ifndef PRODUCT
1575 fdStream out(defaultStream::output_fd());
1576 out.print_raw("Current thread is ");
1577 char buf[16];
1578 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1579 out.print_raw_cr(buf);
1580 out.print_raw_cr("Dumping core ...");
1581 #endif
1582 ::abort(); // dump core
1583 }
1585 ::exit(1);
1586 }
1588 // Die immediately, no exit hook, no abort hook, no cleanup.
1589 void os::die() {
1590 // _exit() on LinuxThreads only kills current thread
1591 ::abort();
1592 }
1594 // unused on linux for now.
1595 void os::set_error_file(const char *logfile) {}
1598 // This method is a copy of JDK's sysGetLastErrorString
1599 // from src/solaris/hpi/src/system_md.c
1601 size_t os::lasterror(char *buf, size_t len) {
1603 if (errno == 0) return 0;
1605 const char *s = ::strerror(errno);
1606 size_t n = ::strlen(s);
1607 if (n >= len) {
1608 n = len - 1;
1609 }
1610 ::strncpy(buf, s, n);
1611 buf[n] = '\0';
1612 return n;
1613 }
1615 intx os::current_thread_id() { return (intx)pthread_self(); }
1616 int os::current_process_id() {
1618 // Under the old linux thread library, linux gives each thread
1619 // its own process id. Because of this each thread will return
1620 // a different pid if this method were to return the result
1621 // of getpid(2). Linux provides no api that returns the pid
1622 // of the launcher thread for the vm. This implementation
1623 // returns a unique pid, the pid of the launcher thread
1624 // that starts the vm 'process'.
1626 // Under the NPTL, getpid() returns the same pid as the
1627 // launcher thread rather than a unique pid per thread.
1628 // Use gettid() if you want the old pre NPTL behaviour.
1630 // if you are looking for the result of a call to getpid() that
1631 // returns a unique pid for the calling thread, then look at the
1632 // OSThread::thread_id() method in osThread_linux.hpp file
1634 return (int)(_initial_pid ? _initial_pid : getpid());
1635 }
1637 // DLL functions
1639 const char* os::dll_file_extension() { return ".so"; }
1641 // This must be hard coded because it's the system's temporary
1642 // directory not the java application's temp directory, ala java.io.tmpdir.
1643 const char* os::get_temp_directory() { return "/tmp"; }
1645 static bool file_exists(const char* filename) {
1646 struct stat statbuf;
1647 if (filename == NULL || strlen(filename) == 0) {
1648 return false;
1649 }
1650 return os::stat(filename, &statbuf) == 0;
1651 }
1653 void os::dll_build_name(char* buffer, size_t buflen,
1654 const char* pname, const char* fname) {
1655 // Copied from libhpi
1656 const size_t pnamelen = pname ? strlen(pname) : 0;
1658 // Quietly truncate on buffer overflow. Should be an error.
1659 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1660 *buffer = '\0';
1661 return;
1662 }
1664 if (pnamelen == 0) {
1665 snprintf(buffer, buflen, "lib%s.so", fname);
1666 } else if (strchr(pname, *os::path_separator()) != NULL) {
1667 int n;
1668 char** pelements = split_path(pname, &n);
1669 for (int i = 0 ; i < n ; i++) {
1670 // Really shouldn't be NULL, but check can't hurt
1671 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1672 continue; // skip the empty path values
1673 }
1674 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1675 if (file_exists(buffer)) {
1676 break;
1677 }
1678 }
1679 // release the storage
1680 for (int i = 0 ; i < n ; i++) {
1681 if (pelements[i] != NULL) {
1682 FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1683 }
1684 }
1685 if (pelements != NULL) {
1686 FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1687 }
1688 } else {
1689 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1690 }
1691 }
1693 const char* os::get_current_directory(char *buf, int buflen) {
1694 return getcwd(buf, buflen);
1695 }
1697 // check if addr is inside libjvm[_g].so
1698 bool os::address_is_in_vm(address addr) {
1699 static address libjvm_base_addr;
1700 Dl_info dlinfo;
1702 if (libjvm_base_addr == NULL) {
1703 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1704 libjvm_base_addr = (address)dlinfo.dli_fbase;
1705 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1706 }
1708 if (dladdr((void *)addr, &dlinfo)) {
1709 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1710 }
1712 return false;
1713 }
1715 bool os::dll_address_to_function_name(address addr, char *buf,
1716 int buflen, int *offset) {
1717 Dl_info dlinfo;
1719 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1720 if (buf != NULL) {
1721 if(!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1722 jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1723 }
1724 }
1725 if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1726 return true;
1727 } else if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != 0) {
1728 if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1729 buf, buflen, offset, dlinfo.dli_fname)) {
1730 return true;
1731 }
1732 }
1734 if (buf != NULL) buf[0] = '\0';
1735 if (offset != NULL) *offset = -1;
1736 return false;
1737 }
1739 struct _address_to_library_name {
1740 address addr; // input : memory address
1741 size_t buflen; // size of fname
1742 char* fname; // output: library name
1743 address base; // library base addr
1744 };
1746 static int address_to_library_name_callback(struct dl_phdr_info *info,
1747 size_t size, void *data) {
1748 int i;
1749 bool found = false;
1750 address libbase = NULL;
1751 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1753 // iterate through all loadable segments
1754 for (i = 0; i < info->dlpi_phnum; i++) {
1755 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1756 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1757 // base address of a library is the lowest address of its loaded
1758 // segments.
1759 if (libbase == NULL || libbase > segbase) {
1760 libbase = segbase;
1761 }
1762 // see if 'addr' is within current segment
1763 if (segbase <= d->addr &&
1764 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1765 found = true;
1766 }
1767 }
1768 }
1770 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1771 // so dll_address_to_library_name() can fall through to use dladdr() which
1772 // can figure out executable name from argv[0].
1773 if (found && info->dlpi_name && info->dlpi_name[0]) {
1774 d->base = libbase;
1775 if (d->fname) {
1776 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1777 }
1778 return 1;
1779 }
1780 return 0;
1781 }
1783 bool os::dll_address_to_library_name(address addr, char* buf,
1784 int buflen, int* offset) {
1785 Dl_info dlinfo;
1786 struct _address_to_library_name data;
1788 // There is a bug in old glibc dladdr() implementation that it could resolve
1789 // to wrong library name if the .so file has a base address != NULL. Here
1790 // we iterate through the program headers of all loaded libraries to find
1791 // out which library 'addr' really belongs to. This workaround can be
1792 // removed once the minimum requirement for glibc is moved to 2.3.x.
1793 data.addr = addr;
1794 data.fname = buf;
1795 data.buflen = buflen;
1796 data.base = NULL;
1797 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1799 if (rslt) {
1800 // buf already contains library name
1801 if (offset) *offset = addr - data.base;
1802 return true;
1803 } else if (dladdr((void*)addr, &dlinfo)){
1804 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1805 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1806 return true;
1807 } else {
1808 if (buf) buf[0] = '\0';
1809 if (offset) *offset = -1;
1810 return false;
1811 }
1812 }
1814 // Loads .dll/.so and
1815 // in case of error it checks if .dll/.so was built for the
1816 // same architecture as Hotspot is running on
1818 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1819 {
1820 void * result= ::dlopen(filename, RTLD_LAZY);
1821 if (result != NULL) {
1822 // Successful loading
1823 return result;
1824 }
1826 Elf32_Ehdr elf_head;
1828 // Read system error message into ebuf
1829 // It may or may not be overwritten below
1830 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1831 ebuf[ebuflen-1]='\0';
1832 int diag_msg_max_length=ebuflen-strlen(ebuf);
1833 char* diag_msg_buf=ebuf+strlen(ebuf);
1835 if (diag_msg_max_length==0) {
1836 // No more space in ebuf for additional diagnostics message
1837 return NULL;
1838 }
1841 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1843 if (file_descriptor < 0) {
1844 // Can't open library, report dlerror() message
1845 return NULL;
1846 }
1848 bool failed_to_read_elf_head=
1849 (sizeof(elf_head)!=
1850 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1852 ::close(file_descriptor);
1853 if (failed_to_read_elf_head) {
1854 // file i/o error - report dlerror() msg
1855 return NULL;
1856 }
1858 typedef struct {
1859 Elf32_Half code; // Actual value as defined in elf.h
1860 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1861 char elf_class; // 32 or 64 bit
1862 char endianess; // MSB or LSB
1863 char* name; // String representation
1864 } arch_t;
1866 #ifndef EM_486
1867 #define EM_486 6 /* Intel 80486 */
1868 #endif
1870 static const arch_t arch_array[]={
1871 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1872 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1873 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1874 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1875 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1876 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1877 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1878 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1879 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1880 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1881 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1882 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1883 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1884 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1885 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1886 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1887 };
1889 #if (defined IA32)
1890 static Elf32_Half running_arch_code=EM_386;
1891 #elif (defined AMD64)
1892 static Elf32_Half running_arch_code=EM_X86_64;
1893 #elif (defined IA64)
1894 static Elf32_Half running_arch_code=EM_IA_64;
1895 #elif (defined __sparc) && (defined _LP64)
1896 static Elf32_Half running_arch_code=EM_SPARCV9;
1897 #elif (defined __sparc) && (!defined _LP64)
1898 static Elf32_Half running_arch_code=EM_SPARC;
1899 #elif (defined __powerpc64__)
1900 static Elf32_Half running_arch_code=EM_PPC64;
1901 #elif (defined __powerpc__)
1902 static Elf32_Half running_arch_code=EM_PPC;
1903 #elif (defined ARM)
1904 static Elf32_Half running_arch_code=EM_ARM;
1905 #elif (defined S390)
1906 static Elf32_Half running_arch_code=EM_S390;
1907 #elif (defined ALPHA)
1908 static Elf32_Half running_arch_code=EM_ALPHA;
1909 #elif (defined MIPSEL)
1910 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1911 #elif (defined PARISC)
1912 static Elf32_Half running_arch_code=EM_PARISC;
1913 #elif (defined MIPS)
1914 static Elf32_Half running_arch_code=EM_MIPS;
1915 #elif (defined M68K)
1916 static Elf32_Half running_arch_code=EM_68K;
1917 #else
1918 #error Method os::dll_load requires that one of following is defined:\
1919 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1920 #endif
1922 // Identify compatability class for VM's architecture and library's architecture
1923 // Obtain string descriptions for architectures
1925 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1926 int running_arch_index=-1;
1928 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1929 if (running_arch_code == arch_array[i].code) {
1930 running_arch_index = i;
1931 }
1932 if (lib_arch.code == arch_array[i].code) {
1933 lib_arch.compat_class = arch_array[i].compat_class;
1934 lib_arch.name = arch_array[i].name;
1935 }
1936 }
1938 assert(running_arch_index != -1,
1939 "Didn't find running architecture code (running_arch_code) in arch_array");
1940 if (running_arch_index == -1) {
1941 // Even though running architecture detection failed
1942 // we may still continue with reporting dlerror() message
1943 return NULL;
1944 }
1946 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1947 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1948 return NULL;
1949 }
1951 #ifndef S390
1952 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1953 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1954 return NULL;
1955 }
1956 #endif // !S390
1958 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1959 if ( lib_arch.name!=NULL ) {
1960 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1961 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1962 lib_arch.name, arch_array[running_arch_index].name);
1963 } else {
1964 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1965 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1966 lib_arch.code,
1967 arch_array[running_arch_index].name);
1968 }
1969 }
1971 return NULL;
1972 }
1974 /*
1975 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1976 * chances are you might want to run the generated bits against glibc-2.0
1977 * libdl.so, so always use locking for any version of glibc.
1978 */
1979 void* os::dll_lookup(void* handle, const char* name) {
1980 pthread_mutex_lock(&dl_mutex);
1981 void* res = dlsym(handle, name);
1982 pthread_mutex_unlock(&dl_mutex);
1983 return res;
1984 }
1987 static bool _print_ascii_file(const char* filename, outputStream* st) {
1988 int fd = ::open(filename, O_RDONLY);
1989 if (fd == -1) {
1990 return false;
1991 }
1993 char buf[32];
1994 int bytes;
1995 while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
1996 st->print_raw(buf, bytes);
1997 }
1999 ::close(fd);
2001 return true;
2002 }
2004 void os::print_dll_info(outputStream *st) {
2005 st->print_cr("Dynamic libraries:");
2007 char fname[32];
2008 pid_t pid = os::Linux::gettid();
2010 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
2012 if (!_print_ascii_file(fname, st)) {
2013 st->print("Can not get library information for pid = %d\n", pid);
2014 }
2015 }
2017 void os::print_os_info_brief(outputStream* st) {
2018 os::Linux::print_distro_info(st);
2020 os::Posix::print_uname_info(st);
2022 os::Linux::print_libversion_info(st);
2024 }
2026 void os::print_os_info(outputStream* st) {
2027 st->print("OS:");
2029 os::Linux::print_distro_info(st);
2031 os::Posix::print_uname_info(st);
2033 // Print warning if unsafe chroot environment detected
2034 if (unsafe_chroot_detected) {
2035 st->print("WARNING!! ");
2036 st->print_cr(unstable_chroot_error);
2037 }
2039 os::Linux::print_libversion_info(st);
2041 os::Posix::print_rlimit_info(st);
2043 os::Posix::print_load_average(st);
2045 os::Linux::print_full_memory_info(st);
2046 }
2048 // Try to identify popular distros.
2049 // Most Linux distributions have /etc/XXX-release file, which contains
2050 // the OS version string. Some have more than one /etc/XXX-release file
2051 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
2052 // so the order is important.
2053 void os::Linux::print_distro_info(outputStream* st) {
2054 if (!_print_ascii_file("/etc/mandrake-release", st) &&
2055 !_print_ascii_file("/etc/sun-release", st) &&
2056 !_print_ascii_file("/etc/redhat-release", st) &&
2057 !_print_ascii_file("/etc/SuSE-release", st) &&
2058 !_print_ascii_file("/etc/turbolinux-release", st) &&
2059 !_print_ascii_file("/etc/gentoo-release", st) &&
2060 !_print_ascii_file("/etc/debian_version", st) &&
2061 !_print_ascii_file("/etc/ltib-release", st) &&
2062 !_print_ascii_file("/etc/angstrom-version", st)) {
2063 st->print("Linux");
2064 }
2065 st->cr();
2066 }
2068 void os::Linux::print_libversion_info(outputStream* st) {
2069 // libc, pthread
2070 st->print("libc:");
2071 st->print(os::Linux::glibc_version()); st->print(" ");
2072 st->print(os::Linux::libpthread_version()); st->print(" ");
2073 if (os::Linux::is_LinuxThreads()) {
2074 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
2075 }
2076 st->cr();
2077 }
2079 void os::Linux::print_full_memory_info(outputStream* st) {
2080 st->print("\n/proc/meminfo:\n");
2081 _print_ascii_file("/proc/meminfo", st);
2082 st->cr();
2083 }
2085 void os::print_memory_info(outputStream* st) {
2087 st->print("Memory:");
2088 st->print(" %dk page", os::vm_page_size()>>10);
2090 // values in struct sysinfo are "unsigned long"
2091 struct sysinfo si;
2092 sysinfo(&si);
2094 st->print(", physical " UINT64_FORMAT "k",
2095 os::physical_memory() >> 10);
2096 st->print("(" UINT64_FORMAT "k free)",
2097 os::available_memory() >> 10);
2098 st->print(", swap " UINT64_FORMAT "k",
2099 ((jlong)si.totalswap * si.mem_unit) >> 10);
2100 st->print("(" UINT64_FORMAT "k free)",
2101 ((jlong)si.freeswap * si.mem_unit) >> 10);
2102 st->cr();
2103 }
2105 void os::pd_print_cpu_info(outputStream* st) {
2106 st->print("\n/proc/cpuinfo:\n");
2107 if (!_print_ascii_file("/proc/cpuinfo", st)) {
2108 st->print(" <Not Available>");
2109 }
2110 st->cr();
2111 }
2113 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
2114 // but they're the same for all the linux arch that we support
2115 // and they're the same for solaris but there's no common place to put this.
2116 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
2117 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
2118 "ILL_COPROC", "ILL_BADSTK" };
2120 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2121 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2122 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2124 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2126 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2128 void os::print_siginfo(outputStream* st, void* siginfo) {
2129 st->print("siginfo:");
2131 const int buflen = 100;
2132 char buf[buflen];
2133 siginfo_t *si = (siginfo_t*)siginfo;
2134 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2135 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2136 st->print("si_errno=%s", buf);
2137 } else {
2138 st->print("si_errno=%d", si->si_errno);
2139 }
2140 const int c = si->si_code;
2141 assert(c > 0, "unexpected si_code");
2142 switch (si->si_signo) {
2143 case SIGILL:
2144 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2145 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2146 break;
2147 case SIGFPE:
2148 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2149 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2150 break;
2151 case SIGSEGV:
2152 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2153 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2154 break;
2155 case SIGBUS:
2156 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2157 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2158 break;
2159 default:
2160 st->print(", si_code=%d", si->si_code);
2161 // no si_addr
2162 }
2164 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2165 UseSharedSpaces) {
2166 FileMapInfo* mapinfo = FileMapInfo::current_info();
2167 if (mapinfo->is_in_shared_space(si->si_addr)) {
2168 st->print("\n\nError accessing class data sharing archive." \
2169 " Mapped file inaccessible during execution, " \
2170 " possible disk/network problem.");
2171 }
2172 }
2173 st->cr();
2174 }
2177 static void print_signal_handler(outputStream* st, int sig,
2178 char* buf, size_t buflen);
2180 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2181 st->print_cr("Signal Handlers:");
2182 print_signal_handler(st, SIGSEGV, buf, buflen);
2183 print_signal_handler(st, SIGBUS , buf, buflen);
2184 print_signal_handler(st, SIGFPE , buf, buflen);
2185 print_signal_handler(st, SIGPIPE, buf, buflen);
2186 print_signal_handler(st, SIGXFSZ, buf, buflen);
2187 print_signal_handler(st, SIGILL , buf, buflen);
2188 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2189 print_signal_handler(st, SR_signum, buf, buflen);
2190 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2191 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2192 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2193 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2194 }
2196 static char saved_jvm_path[MAXPATHLEN] = {0};
2198 // Find the full path to the current module, libjvm.so or libjvm_g.so
2199 void os::jvm_path(char *buf, jint buflen) {
2200 // Error checking.
2201 if (buflen < MAXPATHLEN) {
2202 assert(false, "must use a large-enough buffer");
2203 buf[0] = '\0';
2204 return;
2205 }
2206 // Lazy resolve the path to current module.
2207 if (saved_jvm_path[0] != 0) {
2208 strcpy(buf, saved_jvm_path);
2209 return;
2210 }
2212 char dli_fname[MAXPATHLEN];
2213 bool ret = dll_address_to_library_name(
2214 CAST_FROM_FN_PTR(address, os::jvm_path),
2215 dli_fname, sizeof(dli_fname), NULL);
2216 assert(ret != 0, "cannot locate libjvm");
2217 char *rp = realpath(dli_fname, buf);
2218 if (rp == NULL)
2219 return;
2221 if (Arguments::created_by_gamma_launcher()) {
2222 // Support for the gamma launcher. Typical value for buf is
2223 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2224 // the right place in the string, then assume we are installed in a JDK and
2225 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2226 // up the path so it looks like libjvm.so is installed there (append a
2227 // fake suffix hotspot/libjvm.so).
2228 const char *p = buf + strlen(buf) - 1;
2229 for (int count = 0; p > buf && count < 5; ++count) {
2230 for (--p; p > buf && *p != '/'; --p)
2231 /* empty */ ;
2232 }
2234 if (strncmp(p, "/jre/lib/", 9) != 0) {
2235 // Look for JAVA_HOME in the environment.
2236 char* java_home_var = ::getenv("JAVA_HOME");
2237 if (java_home_var != NULL && java_home_var[0] != 0) {
2238 char* jrelib_p;
2239 int len;
2241 // Check the current module name "libjvm.so" or "libjvm_g.so".
2242 p = strrchr(buf, '/');
2243 assert(strstr(p, "/libjvm") == p, "invalid library name");
2244 p = strstr(p, "_g") ? "_g" : "";
2246 rp = realpath(java_home_var, buf);
2247 if (rp == NULL)
2248 return;
2250 // determine if this is a legacy image or modules image
2251 // modules image doesn't have "jre" subdirectory
2252 len = strlen(buf);
2253 jrelib_p = buf + len;
2254 snprintf(jrelib_p, buflen-len, "/jre/lib/%s", cpu_arch);
2255 if (0 != access(buf, F_OK)) {
2256 snprintf(jrelib_p, buflen-len, "/lib/%s", cpu_arch);
2257 }
2259 if (0 == access(buf, F_OK)) {
2260 // Use current module name "libjvm[_g].so" instead of
2261 // "libjvm"debug_only("_g")".so" since for fastdebug version
2262 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2263 len = strlen(buf);
2264 snprintf(buf + len, buflen-len, "/hotspot/libjvm%s.so", p);
2265 } else {
2266 // Go back to path of .so
2267 rp = realpath(dli_fname, buf);
2268 if (rp == NULL)
2269 return;
2270 }
2271 }
2272 }
2273 }
2275 strcpy(saved_jvm_path, buf);
2276 }
2278 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2279 // no prefix required, not even "_"
2280 }
2282 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2283 // no suffix required
2284 }
2286 ////////////////////////////////////////////////////////////////////////////////
2287 // sun.misc.Signal support
2289 static volatile jint sigint_count = 0;
2291 static void
2292 UserHandler(int sig, void *siginfo, void *context) {
2293 // 4511530 - sem_post is serialized and handled by the manager thread. When
2294 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2295 // don't want to flood the manager thread with sem_post requests.
2296 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2297 return;
2299 // Ctrl-C is pressed during error reporting, likely because the error
2300 // handler fails to abort. Let VM die immediately.
2301 if (sig == SIGINT && is_error_reported()) {
2302 os::die();
2303 }
2305 os::signal_notify(sig);
2306 }
2308 void* os::user_handler() {
2309 return CAST_FROM_FN_PTR(void*, UserHandler);
2310 }
2312 extern "C" {
2313 typedef void (*sa_handler_t)(int);
2314 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2315 }
2317 void* os::signal(int signal_number, void* handler) {
2318 struct sigaction sigAct, oldSigAct;
2320 sigfillset(&(sigAct.sa_mask));
2321 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2322 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2324 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2325 // -1 means registration failed
2326 return (void *)-1;
2327 }
2329 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2330 }
2332 void os::signal_raise(int signal_number) {
2333 ::raise(signal_number);
2334 }
2336 /*
2337 * The following code is moved from os.cpp for making this
2338 * code platform specific, which it is by its very nature.
2339 */
2341 // Will be modified when max signal is changed to be dynamic
2342 int os::sigexitnum_pd() {
2343 return NSIG;
2344 }
2346 // a counter for each possible signal value
2347 static volatile jint pending_signals[NSIG+1] = { 0 };
2349 // Linux(POSIX) specific hand shaking semaphore.
2350 static sem_t sig_sem;
2352 void os::signal_init_pd() {
2353 // Initialize signal structures
2354 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2356 // Initialize signal semaphore
2357 ::sem_init(&sig_sem, 0, 0);
2358 }
2360 void os::signal_notify(int sig) {
2361 Atomic::inc(&pending_signals[sig]);
2362 ::sem_post(&sig_sem);
2363 }
2365 static int check_pending_signals(bool wait) {
2366 Atomic::store(0, &sigint_count);
2367 for (;;) {
2368 for (int i = 0; i < NSIG + 1; i++) {
2369 jint n = pending_signals[i];
2370 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2371 return i;
2372 }
2373 }
2374 if (!wait) {
2375 return -1;
2376 }
2377 JavaThread *thread = JavaThread::current();
2378 ThreadBlockInVM tbivm(thread);
2380 bool threadIsSuspended;
2381 do {
2382 thread->set_suspend_equivalent();
2383 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2384 ::sem_wait(&sig_sem);
2386 // were we externally suspended while we were waiting?
2387 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2388 if (threadIsSuspended) {
2389 //
2390 // The semaphore has been incremented, but while we were waiting
2391 // another thread suspended us. We don't want to continue running
2392 // while suspended because that would surprise the thread that
2393 // suspended us.
2394 //
2395 ::sem_post(&sig_sem);
2397 thread->java_suspend_self();
2398 }
2399 } while (threadIsSuspended);
2400 }
2401 }
2403 int os::signal_lookup() {
2404 return check_pending_signals(false);
2405 }
2407 int os::signal_wait() {
2408 return check_pending_signals(true);
2409 }
2411 ////////////////////////////////////////////////////////////////////////////////
2412 // Virtual Memory
2414 int os::vm_page_size() {
2415 // Seems redundant as all get out
2416 assert(os::Linux::page_size() != -1, "must call os::init");
2417 return os::Linux::page_size();
2418 }
2420 // Solaris allocates memory by pages.
2421 int os::vm_allocation_granularity() {
2422 assert(os::Linux::page_size() != -1, "must call os::init");
2423 return os::Linux::page_size();
2424 }
2426 // Rationale behind this function:
2427 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2428 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2429 // samples for JITted code. Here we create private executable mapping over the code cache
2430 // and then we can use standard (well, almost, as mapping can change) way to provide
2431 // info for the reporting script by storing timestamp and location of symbol
2432 void linux_wrap_code(char* base, size_t size) {
2433 static volatile jint cnt = 0;
2435 if (!UseOprofile) {
2436 return;
2437 }
2439 char buf[PATH_MAX+1];
2440 int num = Atomic::add(1, &cnt);
2442 snprintf(buf, sizeof(buf), "%s/hs-vm-%d-%d",
2443 os::get_temp_directory(), os::current_process_id(), num);
2444 unlink(buf);
2446 int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2448 if (fd != -1) {
2449 off_t rv = ::lseek(fd, size-2, SEEK_SET);
2450 if (rv != (off_t)-1) {
2451 if (::write(fd, "", 1) == 1) {
2452 mmap(base, size,
2453 PROT_READ|PROT_WRITE|PROT_EXEC,
2454 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2455 }
2456 }
2457 ::close(fd);
2458 unlink(buf);
2459 }
2460 }
2462 // NOTE: Linux kernel does not really reserve the pages for us.
2463 // All it does is to check if there are enough free pages
2464 // left at the time of mmap(). This could be a potential
2465 // problem.
2466 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2467 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2468 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2469 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2470 if (res != (uintptr_t) MAP_FAILED) {
2471 if (UseNUMAInterleaving) {
2472 numa_make_global(addr, size);
2473 }
2474 return true;
2475 }
2476 return false;
2477 }
2479 // Define MAP_HUGETLB here so we can build HotSpot on old systems.
2480 #ifndef MAP_HUGETLB
2481 #define MAP_HUGETLB 0x40000
2482 #endif
2484 // Define MADV_HUGEPAGE here so we can build HotSpot on old systems.
2485 #ifndef MADV_HUGEPAGE
2486 #define MADV_HUGEPAGE 14
2487 #endif
2489 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2490 bool exec) {
2491 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2492 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2493 uintptr_t res =
2494 (uintptr_t) ::mmap(addr, size, prot,
2495 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_HUGETLB,
2496 -1, 0);
2497 if (res != (uintptr_t) MAP_FAILED) {
2498 if (UseNUMAInterleaving) {
2499 numa_make_global(addr, size);
2500 }
2501 return true;
2502 }
2503 // Fall through and try to use small pages
2504 }
2506 if (commit_memory(addr, size, exec)) {
2507 realign_memory(addr, size, alignment_hint);
2508 return true;
2509 }
2510 return false;
2511 }
2513 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2514 if (UseHugeTLBFS && alignment_hint > (size_t)vm_page_size()) {
2515 // We don't check the return value: madvise(MADV_HUGEPAGE) may not
2516 // be supported or the memory may already be backed by huge pages.
2517 ::madvise(addr, bytes, MADV_HUGEPAGE);
2518 }
2519 }
2521 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2522 // This method works by doing an mmap over an existing mmaping and effectively discarding
2523 // the existing pages. However it won't work for SHM-based large pages that cannot be
2524 // uncommitted at all. We don't do anything in this case to avoid creating a segment with
2525 // small pages on top of the SHM segment. This method always works for small pages, so we
2526 // allow that in any case.
2527 if (alignment_hint <= (size_t)os::vm_page_size() || !UseSHM) {
2528 commit_memory(addr, bytes, alignment_hint, false);
2529 }
2530 }
2532 void os::numa_make_global(char *addr, size_t bytes) {
2533 Linux::numa_interleave_memory(addr, bytes);
2534 }
2536 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2537 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2538 }
2540 bool os::numa_topology_changed() { return false; }
2542 size_t os::numa_get_groups_num() {
2543 int max_node = Linux::numa_max_node();
2544 return max_node > 0 ? max_node + 1 : 1;
2545 }
2547 int os::numa_get_group_id() {
2548 int cpu_id = Linux::sched_getcpu();
2549 if (cpu_id != -1) {
2550 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2551 if (lgrp_id != -1) {
2552 return lgrp_id;
2553 }
2554 }
2555 return 0;
2556 }
2558 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2559 for (size_t i = 0; i < size; i++) {
2560 ids[i] = i;
2561 }
2562 return size;
2563 }
2565 bool os::get_page_info(char *start, page_info* info) {
2566 return false;
2567 }
2569 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2570 return end;
2571 }
2574 int os::Linux::sched_getcpu_syscall(void) {
2575 unsigned int cpu;
2576 int retval = -1;
2578 #if defined(IA32)
2579 # ifndef SYS_getcpu
2580 # define SYS_getcpu 318
2581 # endif
2582 retval = syscall(SYS_getcpu, &cpu, NULL, NULL);
2583 #elif defined(AMD64)
2584 // Unfortunately we have to bring all these macros here from vsyscall.h
2585 // to be able to compile on old linuxes.
2586 # define __NR_vgetcpu 2
2587 # define VSYSCALL_START (-10UL << 20)
2588 # define VSYSCALL_SIZE 1024
2589 # define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
2590 typedef long (*vgetcpu_t)(unsigned int *cpu, unsigned int *node, unsigned long *tcache);
2591 vgetcpu_t vgetcpu = (vgetcpu_t)VSYSCALL_ADDR(__NR_vgetcpu);
2592 retval = vgetcpu(&cpu, NULL, NULL);
2593 #endif
2595 return (retval == -1) ? retval : cpu;
2596 }
2598 // Something to do with the numa-aware allocator needs these symbols
2599 extern "C" JNIEXPORT void numa_warn(int number, char *where, ...) { }
2600 extern "C" JNIEXPORT void numa_error(char *where) { }
2601 extern "C" JNIEXPORT int fork1() { return fork(); }
2604 // If we are running with libnuma version > 2, then we should
2605 // be trying to use symbols with versions 1.1
2606 // If we are running with earlier version, which did not have symbol versions,
2607 // we should use the base version.
2608 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2609 void *f = dlvsym(handle, name, "libnuma_1.1");
2610 if (f == NULL) {
2611 f = dlsym(handle, name);
2612 }
2613 return f;
2614 }
2616 bool os::Linux::libnuma_init() {
2617 // sched_getcpu() should be in libc.
2618 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2619 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2621 // If it's not, try a direct syscall.
2622 if (sched_getcpu() == -1)
2623 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t, (void*)&sched_getcpu_syscall));
2625 if (sched_getcpu() != -1) { // Does it work?
2626 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2627 if (handle != NULL) {
2628 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2629 libnuma_dlsym(handle, "numa_node_to_cpus")));
2630 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2631 libnuma_dlsym(handle, "numa_max_node")));
2632 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2633 libnuma_dlsym(handle, "numa_available")));
2634 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2635 libnuma_dlsym(handle, "numa_tonode_memory")));
2636 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2637 libnuma_dlsym(handle, "numa_interleave_memory")));
2640 if (numa_available() != -1) {
2641 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2642 // Create a cpu -> node mapping
2643 _cpu_to_node = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int>(0, true);
2644 rebuild_cpu_to_node_map();
2645 return true;
2646 }
2647 }
2648 }
2649 return false;
2650 }
2652 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2653 // The table is later used in get_node_by_cpu().
2654 void os::Linux::rebuild_cpu_to_node_map() {
2655 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2656 // in libnuma (possible values are starting from 16,
2657 // and continuing up with every other power of 2, but less
2658 // than the maximum number of CPUs supported by kernel), and
2659 // is a subject to change (in libnuma version 2 the requirements
2660 // are more reasonable) we'll just hardcode the number they use
2661 // in the library.
2662 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2664 size_t cpu_num = os::active_processor_count();
2665 size_t cpu_map_size = NCPUS / BitsPerCLong;
2666 size_t cpu_map_valid_size =
2667 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2669 cpu_to_node()->clear();
2670 cpu_to_node()->at_grow(cpu_num - 1);
2671 size_t node_num = numa_get_groups_num();
2673 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size, mtInternal);
2674 for (size_t i = 0; i < node_num; i++) {
2675 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2676 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2677 if (cpu_map[j] != 0) {
2678 for (size_t k = 0; k < BitsPerCLong; k++) {
2679 if (cpu_map[j] & (1UL << k)) {
2680 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2681 }
2682 }
2683 }
2684 }
2685 }
2686 }
2687 FREE_C_HEAP_ARRAY(unsigned long, cpu_map, mtInternal);
2688 }
2690 int os::Linux::get_node_by_cpu(int cpu_id) {
2691 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2692 return cpu_to_node()->at(cpu_id);
2693 }
2694 return -1;
2695 }
2697 GrowableArray<int>* os::Linux::_cpu_to_node;
2698 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2699 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2700 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2701 os::Linux::numa_available_func_t os::Linux::_numa_available;
2702 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2703 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2704 unsigned long* os::Linux::_numa_all_nodes;
2706 bool os::pd_uncommit_memory(char* addr, size_t size) {
2707 uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2708 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2709 return res != (uintptr_t) MAP_FAILED;
2710 }
2712 // Linux uses a growable mapping for the stack, and if the mapping for
2713 // the stack guard pages is not removed when we detach a thread the
2714 // stack cannot grow beyond the pages where the stack guard was
2715 // mapped. If at some point later in the process the stack expands to
2716 // that point, the Linux kernel cannot expand the stack any further
2717 // because the guard pages are in the way, and a segfault occurs.
2718 //
2719 // However, it's essential not to split the stack region by unmapping
2720 // a region (leaving a hole) that's already part of the stack mapping,
2721 // so if the stack mapping has already grown beyond the guard pages at
2722 // the time we create them, we have to truncate the stack mapping.
2723 // So, we need to know the extent of the stack mapping when
2724 // create_stack_guard_pages() is called.
2726 // Find the bounds of the stack mapping. Return true for success.
2727 //
2728 // We only need this for stacks that are growable: at the time of
2729 // writing thread stacks don't use growable mappings (i.e. those
2730 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2731 // only applies to the main thread.
2733 static
2734 bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
2736 char buf[128];
2737 int fd, sz;
2739 if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
2740 return false;
2741 }
2743 const char kw[] = "[stack]";
2744 const int kwlen = sizeof(kw)-1;
2746 // Address part of /proc/self/maps couldn't be more than 128 bytes
2747 while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
2748 if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
2749 // Extract addresses
2750 if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2751 uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
2752 if (sp >= *bottom && sp <= *top) {
2753 ::close(fd);
2754 return true;
2755 }
2756 }
2757 }
2758 }
2760 ::close(fd);
2761 return false;
2762 }
2765 // If the (growable) stack mapping already extends beyond the point
2766 // where we're going to put our guard pages, truncate the mapping at
2767 // that point by munmap()ping it. This ensures that when we later
2768 // munmap() the guard pages we don't leave a hole in the stack
2769 // mapping. This only affects the main/initial thread, but guard
2770 // against future OS changes
2771 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2772 uintptr_t stack_extent, stack_base;
2773 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2774 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2775 assert(os::Linux::is_initial_thread(),
2776 "growable stack in non-initial thread");
2777 if (stack_extent < (uintptr_t)addr)
2778 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2779 }
2781 return os::commit_memory(addr, size);
2782 }
2784 // If this is a growable mapping, remove the guard pages entirely by
2785 // munmap()ping them. If not, just call uncommit_memory(). This only
2786 // affects the main/initial thread, but guard against future OS changes
2787 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2788 uintptr_t stack_extent, stack_base;
2789 bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
2790 if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
2791 assert(os::Linux::is_initial_thread(),
2792 "growable stack in non-initial thread");
2794 return ::munmap(addr, size) == 0;
2795 }
2797 return os::uncommit_memory(addr, size);
2798 }
2800 static address _highest_vm_reserved_address = NULL;
2802 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2803 // at 'requested_addr'. If there are existing memory mappings at the same
2804 // location, however, they will be overwritten. If 'fixed' is false,
2805 // 'requested_addr' is only treated as a hint, the return value may or
2806 // may not start from the requested address. Unlike Linux mmap(), this
2807 // function returns NULL to indicate failure.
2808 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2809 char * addr;
2810 int flags;
2812 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2813 if (fixed) {
2814 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2815 flags |= MAP_FIXED;
2816 }
2818 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2819 // to PROT_EXEC if executable when we commit the page.
2820 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2821 flags, -1, 0);
2823 if (addr != MAP_FAILED) {
2824 // anon_mmap() should only get called during VM initialization,
2825 // don't need lock (actually we can skip locking even it can be called
2826 // from multiple threads, because _highest_vm_reserved_address is just a
2827 // hint about the upper limit of non-stack memory regions.)
2828 if ((address)addr + bytes > _highest_vm_reserved_address) {
2829 _highest_vm_reserved_address = (address)addr + bytes;
2830 }
2831 }
2833 return addr == MAP_FAILED ? NULL : addr;
2834 }
2836 // Don't update _highest_vm_reserved_address, because there might be memory
2837 // regions above addr + size. If so, releasing a memory region only creates
2838 // a hole in the address space, it doesn't help prevent heap-stack collision.
2839 //
2840 static int anon_munmap(char * addr, size_t size) {
2841 return ::munmap(addr, size) == 0;
2842 }
2844 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
2845 size_t alignment_hint) {
2846 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2847 }
2849 bool os::pd_release_memory(char* addr, size_t size) {
2850 return anon_munmap(addr, size);
2851 }
2853 static address highest_vm_reserved_address() {
2854 return _highest_vm_reserved_address;
2855 }
2857 static bool linux_mprotect(char* addr, size_t size, int prot) {
2858 // Linux wants the mprotect address argument to be page aligned.
2859 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2861 // According to SUSv3, mprotect() should only be used with mappings
2862 // established by mmap(), and mmap() always maps whole pages. Unaligned
2863 // 'addr' likely indicates problem in the VM (e.g. trying to change
2864 // protection of malloc'ed or statically allocated memory). Check the
2865 // caller if you hit this assert.
2866 assert(addr == bottom, "sanity check");
2868 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2869 return ::mprotect(bottom, size, prot) == 0;
2870 }
2872 // Set protections specified
2873 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2874 bool is_committed) {
2875 unsigned int p = 0;
2876 switch (prot) {
2877 case MEM_PROT_NONE: p = PROT_NONE; break;
2878 case MEM_PROT_READ: p = PROT_READ; break;
2879 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2880 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2881 default:
2882 ShouldNotReachHere();
2883 }
2884 // is_committed is unused.
2885 return linux_mprotect(addr, bytes, p);
2886 }
2888 bool os::guard_memory(char* addr, size_t size) {
2889 return linux_mprotect(addr, size, PROT_NONE);
2890 }
2892 bool os::unguard_memory(char* addr, size_t size) {
2893 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2894 }
2896 bool os::Linux::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2897 bool result = false;
2898 void *p = mmap (NULL, page_size, PROT_READ|PROT_WRITE,
2899 MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB,
2900 -1, 0);
2902 if (p != (void *) -1) {
2903 // We don't know if this really is a huge page or not.
2904 FILE *fp = fopen("/proc/self/maps", "r");
2905 if (fp) {
2906 while (!feof(fp)) {
2907 char chars[257];
2908 long x = 0;
2909 if (fgets(chars, sizeof(chars), fp)) {
2910 if (sscanf(chars, "%lx-%*x", &x) == 1
2911 && x == (long)p) {
2912 if (strstr (chars, "hugepage")) {
2913 result = true;
2914 break;
2915 }
2916 }
2917 }
2918 }
2919 fclose(fp);
2920 }
2921 munmap (p, page_size);
2922 if (result)
2923 return true;
2924 }
2926 if (warn) {
2927 warning("HugeTLBFS is not supported by the operating system.");
2928 }
2930 return result;
2931 }
2933 /*
2934 * Set the coredump_filter bits to include largepages in core dump (bit 6)
2935 *
2936 * From the coredump_filter documentation:
2937 *
2938 * - (bit 0) anonymous private memory
2939 * - (bit 1) anonymous shared memory
2940 * - (bit 2) file-backed private memory
2941 * - (bit 3) file-backed shared memory
2942 * - (bit 4) ELF header pages in file-backed private memory areas (it is
2943 * effective only if the bit 2 is cleared)
2944 * - (bit 5) hugetlb private memory
2945 * - (bit 6) hugetlb shared memory
2946 */
2947 static void set_coredump_filter(void) {
2948 FILE *f;
2949 long cdm;
2951 if ((f = fopen("/proc/self/coredump_filter", "r+")) == NULL) {
2952 return;
2953 }
2955 if (fscanf(f, "%lx", &cdm) != 1) {
2956 fclose(f);
2957 return;
2958 }
2960 rewind(f);
2962 if ((cdm & LARGEPAGES_BIT) == 0) {
2963 cdm |= LARGEPAGES_BIT;
2964 fprintf(f, "%#lx", cdm);
2965 }
2967 fclose(f);
2968 }
2970 // Large page support
2972 static size_t _large_page_size = 0;
2974 void os::large_page_init() {
2975 if (!UseLargePages) {
2976 UseHugeTLBFS = false;
2977 UseSHM = false;
2978 return;
2979 }
2981 if (FLAG_IS_DEFAULT(UseHugeTLBFS) && FLAG_IS_DEFAULT(UseSHM)) {
2982 // If UseLargePages is specified on the command line try both methods,
2983 // if it's default, then try only HugeTLBFS.
2984 if (FLAG_IS_DEFAULT(UseLargePages)) {
2985 UseHugeTLBFS = true;
2986 } else {
2987 UseHugeTLBFS = UseSHM = true;
2988 }
2989 }
2991 if (LargePageSizeInBytes) {
2992 _large_page_size = LargePageSizeInBytes;
2993 } else {
2994 // large_page_size on Linux is used to round up heap size. x86 uses either
2995 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
2996 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
2997 // page as large as 256M.
2998 //
2999 // Here we try to figure out page size by parsing /proc/meminfo and looking
3000 // for a line with the following format:
3001 // Hugepagesize: 2048 kB
3002 //
3003 // If we can't determine the value (e.g. /proc is not mounted, or the text
3004 // format has been changed), we'll use the largest page size supported by
3005 // the processor.
3007 #ifndef ZERO
3008 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M)
3009 ARM_ONLY(2 * M) PPC_ONLY(4 * M);
3010 #endif // ZERO
3012 FILE *fp = fopen("/proc/meminfo", "r");
3013 if (fp) {
3014 while (!feof(fp)) {
3015 int x = 0;
3016 char buf[16];
3017 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
3018 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
3019 _large_page_size = x * K;
3020 break;
3021 }
3022 } else {
3023 // skip to next line
3024 for (;;) {
3025 int ch = fgetc(fp);
3026 if (ch == EOF || ch == (int)'\n') break;
3027 }
3028 }
3029 }
3030 fclose(fp);
3031 }
3032 }
3034 // print a warning if any large page related flag is specified on command line
3035 bool warn_on_failure = !FLAG_IS_DEFAULT(UseHugeTLBFS);
3037 const size_t default_page_size = (size_t)Linux::page_size();
3038 if (_large_page_size > default_page_size) {
3039 _page_sizes[0] = _large_page_size;
3040 _page_sizes[1] = default_page_size;
3041 _page_sizes[2] = 0;
3042 }
3043 UseHugeTLBFS = UseHugeTLBFS &&
3044 Linux::hugetlbfs_sanity_check(warn_on_failure, _large_page_size);
3046 if (UseHugeTLBFS)
3047 UseSHM = false;
3049 UseLargePages = UseHugeTLBFS || UseSHM;
3051 set_coredump_filter();
3052 }
3054 #ifndef SHM_HUGETLB
3055 #define SHM_HUGETLB 04000
3056 #endif
3058 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
3059 // "exec" is passed in but not used. Creating the shared image for
3060 // the code cache doesn't have an SHM_X executable permission to check.
3061 assert(UseLargePages && UseSHM, "only for SHM large pages");
3063 key_t key = IPC_PRIVATE;
3064 char *addr;
3066 bool warn_on_failure = UseLargePages &&
3067 (!FLAG_IS_DEFAULT(UseLargePages) ||
3068 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
3069 );
3070 char msg[128];
3072 // Create a large shared memory region to attach to based on size.
3073 // Currently, size is the total size of the heap
3074 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
3075 if (shmid == -1) {
3076 // Possible reasons for shmget failure:
3077 // 1. shmmax is too small for Java heap.
3078 // > check shmmax value: cat /proc/sys/kernel/shmmax
3079 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
3080 // 2. not enough large page memory.
3081 // > check available large pages: cat /proc/meminfo
3082 // > increase amount of large pages:
3083 // echo new_value > /proc/sys/vm/nr_hugepages
3084 // Note 1: different Linux may use different name for this property,
3085 // e.g. on Redhat AS-3 it is "hugetlb_pool".
3086 // Note 2: it's possible there's enough physical memory available but
3087 // they are so fragmented after a long run that they can't
3088 // coalesce into large pages. Try to reserve large pages when
3089 // the system is still "fresh".
3090 if (warn_on_failure) {
3091 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
3092 warning(msg);
3093 }
3094 return NULL;
3095 }
3097 // attach to the region
3098 addr = (char*)shmat(shmid, req_addr, 0);
3099 int err = errno;
3101 // Remove shmid. If shmat() is successful, the actual shared memory segment
3102 // will be deleted when it's detached by shmdt() or when the process
3103 // terminates. If shmat() is not successful this will remove the shared
3104 // segment immediately.
3105 shmctl(shmid, IPC_RMID, NULL);
3107 if ((intptr_t)addr == -1) {
3108 if (warn_on_failure) {
3109 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
3110 warning(msg);
3111 }
3112 return NULL;
3113 }
3115 if ((addr != NULL) && UseNUMAInterleaving) {
3116 numa_make_global(addr, bytes);
3117 }
3119 return addr;
3120 }
3122 bool os::release_memory_special(char* base, size_t bytes) {
3123 // detaching the SHM segment will also delete it, see reserve_memory_special()
3124 int rslt = shmdt(base);
3125 return rslt == 0;
3126 }
3128 size_t os::large_page_size() {
3129 return _large_page_size;
3130 }
3132 // HugeTLBFS allows application to commit large page memory on demand;
3133 // with SysV SHM the entire memory region must be allocated as shared
3134 // memory.
3135 bool os::can_commit_large_page_memory() {
3136 return UseHugeTLBFS;
3137 }
3139 bool os::can_execute_large_page_memory() {
3140 return UseHugeTLBFS;
3141 }
3143 // Reserve memory at an arbitrary address, only if that area is
3144 // available (and not reserved for something else).
3146 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
3147 const int max_tries = 10;
3148 char* base[max_tries];
3149 size_t size[max_tries];
3150 const size_t gap = 0x000000;
3152 // Assert only that the size is a multiple of the page size, since
3153 // that's all that mmap requires, and since that's all we really know
3154 // about at this low abstraction level. If we need higher alignment,
3155 // we can either pass an alignment to this method or verify alignment
3156 // in one of the methods further up the call chain. See bug 5044738.
3157 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
3159 // Repeatedly allocate blocks until the block is allocated at the
3160 // right spot. Give up after max_tries. Note that reserve_memory() will
3161 // automatically update _highest_vm_reserved_address if the call is
3162 // successful. The variable tracks the highest memory address every reserved
3163 // by JVM. It is used to detect heap-stack collision if running with
3164 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
3165 // space than needed, it could confuse the collision detecting code. To
3166 // solve the problem, save current _highest_vm_reserved_address and
3167 // calculate the correct value before return.
3168 address old_highest = _highest_vm_reserved_address;
3170 // Linux mmap allows caller to pass an address as hint; give it a try first,
3171 // if kernel honors the hint then we can return immediately.
3172 char * addr = anon_mmap(requested_addr, bytes, false);
3173 if (addr == requested_addr) {
3174 return requested_addr;
3175 }
3177 if (addr != NULL) {
3178 // mmap() is successful but it fails to reserve at the requested address
3179 anon_munmap(addr, bytes);
3180 }
3182 int i;
3183 for (i = 0; i < max_tries; ++i) {
3184 base[i] = reserve_memory(bytes);
3186 if (base[i] != NULL) {
3187 // Is this the block we wanted?
3188 if (base[i] == requested_addr) {
3189 size[i] = bytes;
3190 break;
3191 }
3193 // Does this overlap the block we wanted? Give back the overlapped
3194 // parts and try again.
3196 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
3197 if (top_overlap >= 0 && top_overlap < bytes) {
3198 unmap_memory(base[i], top_overlap);
3199 base[i] += top_overlap;
3200 size[i] = bytes - top_overlap;
3201 } else {
3202 size_t bottom_overlap = base[i] + bytes - requested_addr;
3203 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
3204 unmap_memory(requested_addr, bottom_overlap);
3205 size[i] = bytes - bottom_overlap;
3206 } else {
3207 size[i] = bytes;
3208 }
3209 }
3210 }
3211 }
3213 // Give back the unused reserved pieces.
3215 for (int j = 0; j < i; ++j) {
3216 if (base[j] != NULL) {
3217 unmap_memory(base[j], size[j]);
3218 }
3219 }
3221 if (i < max_tries) {
3222 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
3223 return requested_addr;
3224 } else {
3225 _highest_vm_reserved_address = old_highest;
3226 return NULL;
3227 }
3228 }
3230 size_t os::read(int fd, void *buf, unsigned int nBytes) {
3231 return ::read(fd, buf, nBytes);
3232 }
3234 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
3235 // Solaris uses poll(), linux uses park().
3236 // Poll() is likely a better choice, assuming that Thread.interrupt()
3237 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
3238 // SIGSEGV, see 4355769.
3240 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
3241 assert(thread == Thread::current(), "thread consistency check");
3243 ParkEvent * const slp = thread->_SleepEvent ;
3244 slp->reset() ;
3245 OrderAccess::fence() ;
3247 if (interruptible) {
3248 jlong prevtime = javaTimeNanos();
3250 for (;;) {
3251 if (os::is_interrupted(thread, true)) {
3252 return OS_INTRPT;
3253 }
3255 jlong newtime = javaTimeNanos();
3257 if (newtime - prevtime < 0) {
3258 // time moving backwards, should only happen if no monotonic clock
3259 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3260 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3261 } else {
3262 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3263 }
3265 if(millis <= 0) {
3266 return OS_OK;
3267 }
3269 prevtime = newtime;
3271 {
3272 assert(thread->is_Java_thread(), "sanity check");
3273 JavaThread *jt = (JavaThread *) thread;
3274 ThreadBlockInVM tbivm(jt);
3275 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
3277 jt->set_suspend_equivalent();
3278 // cleared by handle_special_suspend_equivalent_condition() or
3279 // java_suspend_self() via check_and_wait_while_suspended()
3281 slp->park(millis);
3283 // were we externally suspended while we were waiting?
3284 jt->check_and_wait_while_suspended();
3285 }
3286 }
3287 } else {
3288 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
3289 jlong prevtime = javaTimeNanos();
3291 for (;;) {
3292 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
3293 // the 1st iteration ...
3294 jlong newtime = javaTimeNanos();
3296 if (newtime - prevtime < 0) {
3297 // time moving backwards, should only happen if no monotonic clock
3298 // not a guarantee() because JVM should not abort on kernel/glibc bugs
3299 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
3300 } else {
3301 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
3302 }
3304 if(millis <= 0) break ;
3306 prevtime = newtime;
3307 slp->park(millis);
3308 }
3309 return OS_OK ;
3310 }
3311 }
3313 int os::naked_sleep() {
3314 // %% make the sleep time an integer flag. for now use 1 millisec.
3315 return os::sleep(Thread::current(), 1, false);
3316 }
3318 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3319 void os::infinite_sleep() {
3320 while (true) { // sleep forever ...
3321 ::sleep(100); // ... 100 seconds at a time
3322 }
3323 }
3325 // Used to convert frequent JVM_Yield() to nops
3326 bool os::dont_yield() {
3327 return DontYieldALot;
3328 }
3330 void os::yield() {
3331 sched_yield();
3332 }
3334 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3336 void os::yield_all(int attempts) {
3337 // Yields to all threads, including threads with lower priorities
3338 // Threads on Linux are all with same priority. The Solaris style
3339 // os::yield_all() with nanosleep(1ms) is not necessary.
3340 sched_yield();
3341 }
3343 // Called from the tight loops to possibly influence time-sharing heuristics
3344 void os::loop_breaker(int attempts) {
3345 os::yield_all(attempts);
3346 }
3348 ////////////////////////////////////////////////////////////////////////////////
3349 // thread priority support
3351 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3352 // only supports dynamic priority, static priority must be zero. For real-time
3353 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3354 // However, for large multi-threaded applications, SCHED_RR is not only slower
3355 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3356 // of 5 runs - Sep 2005).
3357 //
3358 // The following code actually changes the niceness of kernel-thread/LWP. It
3359 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3360 // not the entire user process, and user level threads are 1:1 mapped to kernel
3361 // threads. It has always been the case, but could change in the future. For
3362 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3363 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3365 int os::java_to_os_priority[CriticalPriority + 1] = {
3366 19, // 0 Entry should never be used
3368 4, // 1 MinPriority
3369 3, // 2
3370 2, // 3
3372 1, // 4
3373 0, // 5 NormPriority
3374 -1, // 6
3376 -2, // 7
3377 -3, // 8
3378 -4, // 9 NearMaxPriority
3380 -5, // 10 MaxPriority
3382 -5 // 11 CriticalPriority
3383 };
3385 static int prio_init() {
3386 if (ThreadPriorityPolicy == 1) {
3387 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3388 // if effective uid is not root. Perhaps, a more elegant way of doing
3389 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3390 if (geteuid() != 0) {
3391 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3392 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3393 }
3394 ThreadPriorityPolicy = 0;
3395 }
3396 }
3397 if (UseCriticalJavaThreadPriority) {
3398 os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
3399 }
3400 return 0;
3401 }
3403 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3404 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3406 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3407 return (ret == 0) ? OS_OK : OS_ERR;
3408 }
3410 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3411 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3412 *priority_ptr = java_to_os_priority[NormPriority];
3413 return OS_OK;
3414 }
3416 errno = 0;
3417 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3418 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3419 }
3421 // Hint to the underlying OS that a task switch would not be good.
3422 // Void return because it's a hint and can fail.
3423 void os::hint_no_preempt() {}
3425 ////////////////////////////////////////////////////////////////////////////////
3426 // suspend/resume support
3428 // the low-level signal-based suspend/resume support is a remnant from the
3429 // old VM-suspension that used to be for java-suspension, safepoints etc,
3430 // within hotspot. Now there is a single use-case for this:
3431 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3432 // that runs in the watcher thread.
3433 // The remaining code is greatly simplified from the more general suspension
3434 // code that used to be used.
3435 //
3436 // The protocol is quite simple:
3437 // - suspend:
3438 // - sends a signal to the target thread
3439 // - polls the suspend state of the osthread using a yield loop
3440 // - target thread signal handler (SR_handler) sets suspend state
3441 // and blocks in sigsuspend until continued
3442 // - resume:
3443 // - sets target osthread state to continue
3444 // - sends signal to end the sigsuspend loop in the SR_handler
3445 //
3446 // Note that the SR_lock plays no role in this suspend/resume protocol.
3447 //
3449 static void resume_clear_context(OSThread *osthread) {
3450 osthread->set_ucontext(NULL);
3451 osthread->set_siginfo(NULL);
3453 // notify the suspend action is completed, we have now resumed
3454 osthread->sr.clear_suspended();
3455 }
3457 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3458 osthread->set_ucontext(context);
3459 osthread->set_siginfo(siginfo);
3460 }
3462 //
3463 // Handler function invoked when a thread's execution is suspended or
3464 // resumed. We have to be careful that only async-safe functions are
3465 // called here (Note: most pthread functions are not async safe and
3466 // should be avoided.)
3467 //
3468 // Note: sigwait() is a more natural fit than sigsuspend() from an
3469 // interface point of view, but sigwait() prevents the signal hander
3470 // from being run. libpthread would get very confused by not having
3471 // its signal handlers run and prevents sigwait()'s use with the
3472 // mutex granting granting signal.
3473 //
3474 // Currently only ever called on the VMThread
3475 //
3476 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3477 // Save and restore errno to avoid confusing native code with EINTR
3478 // after sigsuspend.
3479 int old_errno = errno;
3481 Thread* thread = Thread::current();
3482 OSThread* osthread = thread->osthread();
3483 assert(thread->is_VM_thread(), "Must be VMThread");
3484 // read current suspend action
3485 int action = osthread->sr.suspend_action();
3486 if (action == SR_SUSPEND) {
3487 suspend_save_context(osthread, siginfo, context);
3489 // Notify the suspend action is about to be completed. do_suspend()
3490 // waits until SR_SUSPENDED is set and then returns. We will wait
3491 // here for a resume signal and that completes the suspend-other
3492 // action. do_suspend/do_resume is always called as a pair from
3493 // the same thread - so there are no races
3495 // notify the caller
3496 osthread->sr.set_suspended();
3498 sigset_t suspend_set; // signals for sigsuspend()
3500 // get current set of blocked signals and unblock resume signal
3501 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3502 sigdelset(&suspend_set, SR_signum);
3504 // wait here until we are resumed
3505 do {
3506 sigsuspend(&suspend_set);
3507 // ignore all returns until we get a resume signal
3508 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3510 resume_clear_context(osthread);
3512 } else {
3513 assert(action == SR_CONTINUE, "unexpected sr action");
3514 // nothing special to do - just leave the handler
3515 }
3517 errno = old_errno;
3518 }
3521 static int SR_initialize() {
3522 struct sigaction act;
3523 char *s;
3524 /* Get signal number to use for suspend/resume */
3525 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3526 int sig = ::strtol(s, 0, 10);
3527 if (sig > 0 || sig < _NSIG) {
3528 SR_signum = sig;
3529 }
3530 }
3532 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3533 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3535 sigemptyset(&SR_sigset);
3536 sigaddset(&SR_sigset, SR_signum);
3538 /* Set up signal handler for suspend/resume */
3539 act.sa_flags = SA_RESTART|SA_SIGINFO;
3540 act.sa_handler = (void (*)(int)) SR_handler;
3542 // SR_signum is blocked by default.
3543 // 4528190 - We also need to block pthread restart signal (32 on all
3544 // supported Linux platforms). Note that LinuxThreads need to block
3545 // this signal for all threads to work properly. So we don't have
3546 // to use hard-coded signal number when setting up the mask.
3547 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3549 if (sigaction(SR_signum, &act, 0) == -1) {
3550 return -1;
3551 }
3553 // Save signal flag
3554 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3555 return 0;
3556 }
3558 static int SR_finalize() {
3559 return 0;
3560 }
3563 // returns true on success and false on error - really an error is fatal
3564 // but this seems the normal response to library errors
3565 static bool do_suspend(OSThread* osthread) {
3566 // mark as suspended and send signal
3567 osthread->sr.set_suspend_action(SR_SUSPEND);
3568 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3569 assert_status(status == 0, status, "pthread_kill");
3571 // check status and wait until notified of suspension
3572 if (status == 0) {
3573 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3574 os::yield_all(i);
3575 }
3576 osthread->sr.set_suspend_action(SR_NONE);
3577 return true;
3578 }
3579 else {
3580 osthread->sr.set_suspend_action(SR_NONE);
3581 return false;
3582 }
3583 }
3585 static void do_resume(OSThread* osthread) {
3586 assert(osthread->sr.is_suspended(), "thread should be suspended");
3587 osthread->sr.set_suspend_action(SR_CONTINUE);
3589 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3590 assert_status(status == 0, status, "pthread_kill");
3591 // check status and wait unit notified of resumption
3592 if (status == 0) {
3593 for (int i = 0; osthread->sr.is_suspended(); i++) {
3594 os::yield_all(i);
3595 }
3596 }
3597 osthread->sr.set_suspend_action(SR_NONE);
3598 }
3600 ////////////////////////////////////////////////////////////////////////////////
3601 // interrupt support
3603 void os::interrupt(Thread* thread) {
3604 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3605 "possibility of dangling Thread pointer");
3607 OSThread* osthread = thread->osthread();
3609 if (!osthread->interrupted()) {
3610 osthread->set_interrupted(true);
3611 // More than one thread can get here with the same value of osthread,
3612 // resulting in multiple notifications. We do, however, want the store
3613 // to interrupted() to be visible to other threads before we execute unpark().
3614 OrderAccess::fence();
3615 ParkEvent * const slp = thread->_SleepEvent ;
3616 if (slp != NULL) slp->unpark() ;
3617 }
3619 // For JSR166. Unpark even if interrupt status already was set
3620 if (thread->is_Java_thread())
3621 ((JavaThread*)thread)->parker()->unpark();
3623 ParkEvent * ev = thread->_ParkEvent ;
3624 if (ev != NULL) ev->unpark() ;
3626 }
3628 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3629 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3630 "possibility of dangling Thread pointer");
3632 OSThread* osthread = thread->osthread();
3634 bool interrupted = osthread->interrupted();
3636 if (interrupted && clear_interrupted) {
3637 osthread->set_interrupted(false);
3638 // consider thread->_SleepEvent->reset() ... optional optimization
3639 }
3641 return interrupted;
3642 }
3644 ///////////////////////////////////////////////////////////////////////////////////
3645 // signal handling (except suspend/resume)
3647 // This routine may be used by user applications as a "hook" to catch signals.
3648 // The user-defined signal handler must pass unrecognized signals to this
3649 // routine, and if it returns true (non-zero), then the signal handler must
3650 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3651 // routine will never retun false (zero), but instead will execute a VM panic
3652 // routine kill the process.
3653 //
3654 // If this routine returns false, it is OK to call it again. This allows
3655 // the user-defined signal handler to perform checks either before or after
3656 // the VM performs its own checks. Naturally, the user code would be making
3657 // a serious error if it tried to handle an exception (such as a null check
3658 // or breakpoint) that the VM was generating for its own correct operation.
3659 //
3660 // This routine may recognize any of the following kinds of signals:
3661 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3662 // It should be consulted by handlers for any of those signals.
3663 //
3664 // The caller of this routine must pass in the three arguments supplied
3665 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3666 // field of the structure passed to sigaction(). This routine assumes that
3667 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3668 //
3669 // Note that the VM will print warnings if it detects conflicting signal
3670 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3671 //
3672 extern "C" JNIEXPORT int
3673 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3674 void* ucontext, int abort_if_unrecognized);
3676 void signalHandler(int sig, siginfo_t* info, void* uc) {
3677 assert(info != NULL && uc != NULL, "it must be old kernel");
3678 JVM_handle_linux_signal(sig, info, uc, true);
3679 }
3682 // This boolean allows users to forward their own non-matching signals
3683 // to JVM_handle_linux_signal, harmlessly.
3684 bool os::Linux::signal_handlers_are_installed = false;
3686 // For signal-chaining
3687 struct sigaction os::Linux::sigact[MAXSIGNUM];
3688 unsigned int os::Linux::sigs = 0;
3689 bool os::Linux::libjsig_is_loaded = false;
3690 typedef struct sigaction *(*get_signal_t)(int);
3691 get_signal_t os::Linux::get_signal_action = NULL;
3693 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3694 struct sigaction *actp = NULL;
3696 if (libjsig_is_loaded) {
3697 // Retrieve the old signal handler from libjsig
3698 actp = (*get_signal_action)(sig);
3699 }
3700 if (actp == NULL) {
3701 // Retrieve the preinstalled signal handler from jvm
3702 actp = get_preinstalled_handler(sig);
3703 }
3705 return actp;
3706 }
3708 static bool call_chained_handler(struct sigaction *actp, int sig,
3709 siginfo_t *siginfo, void *context) {
3710 // Call the old signal handler
3711 if (actp->sa_handler == SIG_DFL) {
3712 // It's more reasonable to let jvm treat it as an unexpected exception
3713 // instead of taking the default action.
3714 return false;
3715 } else if (actp->sa_handler != SIG_IGN) {
3716 if ((actp->sa_flags & SA_NODEFER) == 0) {
3717 // automaticlly block the signal
3718 sigaddset(&(actp->sa_mask), sig);
3719 }
3721 sa_handler_t hand;
3722 sa_sigaction_t sa;
3723 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3724 // retrieve the chained handler
3725 if (siginfo_flag_set) {
3726 sa = actp->sa_sigaction;
3727 } else {
3728 hand = actp->sa_handler;
3729 }
3731 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3732 actp->sa_handler = SIG_DFL;
3733 }
3735 // try to honor the signal mask
3736 sigset_t oset;
3737 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3739 // call into the chained handler
3740 if (siginfo_flag_set) {
3741 (*sa)(sig, siginfo, context);
3742 } else {
3743 (*hand)(sig);
3744 }
3746 // restore the signal mask
3747 pthread_sigmask(SIG_SETMASK, &oset, 0);
3748 }
3749 // Tell jvm's signal handler the signal is taken care of.
3750 return true;
3751 }
3753 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3754 bool chained = false;
3755 // signal-chaining
3756 if (UseSignalChaining) {
3757 struct sigaction *actp = get_chained_signal_action(sig);
3758 if (actp != NULL) {
3759 chained = call_chained_handler(actp, sig, siginfo, context);
3760 }
3761 }
3762 return chained;
3763 }
3765 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3766 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3767 return &sigact[sig];
3768 }
3769 return NULL;
3770 }
3772 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3773 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3774 sigact[sig] = oldAct;
3775 sigs |= (unsigned int)1 << sig;
3776 }
3778 // for diagnostic
3779 int os::Linux::sigflags[MAXSIGNUM];
3781 int os::Linux::get_our_sigflags(int sig) {
3782 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3783 return sigflags[sig];
3784 }
3786 void os::Linux::set_our_sigflags(int sig, int flags) {
3787 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3788 sigflags[sig] = flags;
3789 }
3791 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3792 // Check for overwrite.
3793 struct sigaction oldAct;
3794 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3796 void* oldhand = oldAct.sa_sigaction
3797 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3798 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3799 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3800 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3801 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3802 if (AllowUserSignalHandlers || !set_installed) {
3803 // Do not overwrite; user takes responsibility to forward to us.
3804 return;
3805 } else if (UseSignalChaining) {
3806 // save the old handler in jvm
3807 save_preinstalled_handler(sig, oldAct);
3808 // libjsig also interposes the sigaction() call below and saves the
3809 // old sigaction on it own.
3810 } else {
3811 fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3812 "%#lx for signal %d.", (long)oldhand, sig));
3813 }
3814 }
3816 struct sigaction sigAct;
3817 sigfillset(&(sigAct.sa_mask));
3818 sigAct.sa_handler = SIG_DFL;
3819 if (!set_installed) {
3820 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3821 } else {
3822 sigAct.sa_sigaction = signalHandler;
3823 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3824 }
3825 // Save flags, which are set by ours
3826 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3827 sigflags[sig] = sigAct.sa_flags;
3829 int ret = sigaction(sig, &sigAct, &oldAct);
3830 assert(ret == 0, "check");
3832 void* oldhand2 = oldAct.sa_sigaction
3833 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3834 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3835 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3836 }
3838 // install signal handlers for signals that HotSpot needs to
3839 // handle in order to support Java-level exception handling.
3841 void os::Linux::install_signal_handlers() {
3842 if (!signal_handlers_are_installed) {
3843 signal_handlers_are_installed = true;
3845 // signal-chaining
3846 typedef void (*signal_setting_t)();
3847 signal_setting_t begin_signal_setting = NULL;
3848 signal_setting_t end_signal_setting = NULL;
3849 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3850 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3851 if (begin_signal_setting != NULL) {
3852 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3853 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3854 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3855 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3856 libjsig_is_loaded = true;
3857 assert(UseSignalChaining, "should enable signal-chaining");
3858 }
3859 if (libjsig_is_loaded) {
3860 // Tell libjsig jvm is setting signal handlers
3861 (*begin_signal_setting)();
3862 }
3864 set_signal_handler(SIGSEGV, true);
3865 set_signal_handler(SIGPIPE, true);
3866 set_signal_handler(SIGBUS, true);
3867 set_signal_handler(SIGILL, true);
3868 set_signal_handler(SIGFPE, true);
3869 set_signal_handler(SIGXFSZ, true);
3871 if (libjsig_is_loaded) {
3872 // Tell libjsig jvm finishes setting signal handlers
3873 (*end_signal_setting)();
3874 }
3876 // We don't activate signal checker if libjsig is in place, we trust ourselves
3877 // and if UserSignalHandler is installed all bets are off.
3878 // Log that signal checking is off only if -verbose:jni is specified.
3879 if (CheckJNICalls) {
3880 if (libjsig_is_loaded) {
3881 if (PrintJNIResolving) {
3882 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3883 }
3884 check_signals = false;
3885 }
3886 if (AllowUserSignalHandlers) {
3887 if (PrintJNIResolving) {
3888 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3889 }
3890 check_signals = false;
3891 }
3892 }
3893 }
3894 }
3896 // This is the fastest way to get thread cpu time on Linux.
3897 // Returns cpu time (user+sys) for any thread, not only for current.
3898 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3899 // It might work on 2.6.10+ with a special kernel/glibc patch.
3900 // For reference, please, see IEEE Std 1003.1-2004:
3901 // http://www.unix.org/single_unix_specification
3903 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3904 struct timespec tp;
3905 int rc = os::Linux::clock_gettime(clockid, &tp);
3906 assert(rc == 0, "clock_gettime is expected to return 0 code");
3908 return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
3909 }
3911 /////
3912 // glibc on Linux platform uses non-documented flag
3913 // to indicate, that some special sort of signal
3914 // trampoline is used.
3915 // We will never set this flag, and we should
3916 // ignore this flag in our diagnostic
3917 #ifdef SIGNIFICANT_SIGNAL_MASK
3918 #undef SIGNIFICANT_SIGNAL_MASK
3919 #endif
3920 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3922 static const char* get_signal_handler_name(address handler,
3923 char* buf, int buflen) {
3924 int offset;
3925 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3926 if (found) {
3927 // skip directory names
3928 const char *p1, *p2;
3929 p1 = buf;
3930 size_t len = strlen(os::file_separator());
3931 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3932 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3933 } else {
3934 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3935 }
3936 return buf;
3937 }
3939 static void print_signal_handler(outputStream* st, int sig,
3940 char* buf, size_t buflen) {
3941 struct sigaction sa;
3943 sigaction(sig, NULL, &sa);
3945 // See comment for SIGNIFICANT_SIGNAL_MASK define
3946 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3948 st->print("%s: ", os::exception_name(sig, buf, buflen));
3950 address handler = (sa.sa_flags & SA_SIGINFO)
3951 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3952 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3954 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3955 st->print("SIG_DFL");
3956 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3957 st->print("SIG_IGN");
3958 } else {
3959 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3960 }
3962 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3964 address rh = VMError::get_resetted_sighandler(sig);
3965 // May be, handler was resetted by VMError?
3966 if(rh != NULL) {
3967 handler = rh;
3968 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3969 }
3971 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3973 // Check: is it our handler?
3974 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3975 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3976 // It is our signal handler
3977 // check for flags, reset system-used one!
3978 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3979 st->print(
3980 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3981 os::Linux::get_our_sigflags(sig));
3982 }
3983 }
3984 st->cr();
3985 }
3988 #define DO_SIGNAL_CHECK(sig) \
3989 if (!sigismember(&check_signal_done, sig)) \
3990 os::Linux::check_signal_handler(sig)
3992 // This method is a periodic task to check for misbehaving JNI applications
3993 // under CheckJNI, we can add any periodic checks here
3995 void os::run_periodic_checks() {
3997 if (check_signals == false) return;
3999 // SEGV and BUS if overridden could potentially prevent
4000 // generation of hs*.log in the event of a crash, debugging
4001 // such a case can be very challenging, so we absolutely
4002 // check the following for a good measure:
4003 DO_SIGNAL_CHECK(SIGSEGV);
4004 DO_SIGNAL_CHECK(SIGILL);
4005 DO_SIGNAL_CHECK(SIGFPE);
4006 DO_SIGNAL_CHECK(SIGBUS);
4007 DO_SIGNAL_CHECK(SIGPIPE);
4008 DO_SIGNAL_CHECK(SIGXFSZ);
4011 // ReduceSignalUsage allows the user to override these handlers
4012 // see comments at the very top and jvm_solaris.h
4013 if (!ReduceSignalUsage) {
4014 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
4015 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
4016 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
4017 DO_SIGNAL_CHECK(BREAK_SIGNAL);
4018 }
4020 DO_SIGNAL_CHECK(SR_signum);
4021 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
4022 }
4024 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
4026 static os_sigaction_t os_sigaction = NULL;
4028 void os::Linux::check_signal_handler(int sig) {
4029 char buf[O_BUFLEN];
4030 address jvmHandler = NULL;
4033 struct sigaction act;
4034 if (os_sigaction == NULL) {
4035 // only trust the default sigaction, in case it has been interposed
4036 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
4037 if (os_sigaction == NULL) return;
4038 }
4040 os_sigaction(sig, (struct sigaction*)NULL, &act);
4043 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
4045 address thisHandler = (act.sa_flags & SA_SIGINFO)
4046 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
4047 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
4050 switch(sig) {
4051 case SIGSEGV:
4052 case SIGBUS:
4053 case SIGFPE:
4054 case SIGPIPE:
4055 case SIGILL:
4056 case SIGXFSZ:
4057 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
4058 break;
4060 case SHUTDOWN1_SIGNAL:
4061 case SHUTDOWN2_SIGNAL:
4062 case SHUTDOWN3_SIGNAL:
4063 case BREAK_SIGNAL:
4064 jvmHandler = (address)user_handler();
4065 break;
4067 case INTERRUPT_SIGNAL:
4068 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
4069 break;
4071 default:
4072 if (sig == SR_signum) {
4073 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
4074 } else {
4075 return;
4076 }
4077 break;
4078 }
4080 if (thisHandler != jvmHandler) {
4081 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
4082 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
4083 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
4084 // No need to check this sig any longer
4085 sigaddset(&check_signal_done, sig);
4086 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
4087 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
4088 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
4089 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
4090 // No need to check this sig any longer
4091 sigaddset(&check_signal_done, sig);
4092 }
4094 // Dump all the signal
4095 if (sigismember(&check_signal_done, sig)) {
4096 print_signal_handlers(tty, buf, O_BUFLEN);
4097 }
4098 }
4100 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
4102 extern bool signal_name(int signo, char* buf, size_t len);
4104 const char* os::exception_name(int exception_code, char* buf, size_t size) {
4105 if (0 < exception_code && exception_code <= SIGRTMAX) {
4106 // signal
4107 if (!signal_name(exception_code, buf, size)) {
4108 jio_snprintf(buf, size, "SIG%d", exception_code);
4109 }
4110 return buf;
4111 } else {
4112 return NULL;
4113 }
4114 }
4116 // this is called _before_ the most of global arguments have been parsed
4117 void os::init(void) {
4118 char dummy; /* used to get a guess on initial stack address */
4119 // first_hrtime = gethrtime();
4121 // With LinuxThreads the JavaMain thread pid (primordial thread)
4122 // is different than the pid of the java launcher thread.
4123 // So, on Linux, the launcher thread pid is passed to the VM
4124 // via the sun.java.launcher.pid property.
4125 // Use this property instead of getpid() if it was correctly passed.
4126 // See bug 6351349.
4127 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
4129 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
4131 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
4133 init_random(1234567);
4135 ThreadCritical::initialize();
4137 Linux::set_page_size(sysconf(_SC_PAGESIZE));
4138 if (Linux::page_size() == -1) {
4139 fatal(err_msg("os_linux.cpp: os::init: sysconf failed (%s)",
4140 strerror(errno)));
4141 }
4142 init_page_sizes((size_t) Linux::page_size());
4144 Linux::initialize_system_info();
4146 // main_thread points to the aboriginal thread
4147 Linux::_main_thread = pthread_self();
4149 Linux::clock_init();
4150 initial_time_count = os::elapsed_counter();
4151 pthread_mutex_init(&dl_mutex, NULL);
4152 }
4154 // To install functions for atexit system call
4155 extern "C" {
4156 static void perfMemory_exit_helper() {
4157 perfMemory_exit();
4158 }
4159 }
4161 // this is called _after_ the global arguments have been parsed
4162 jint os::init_2(void)
4163 {
4164 Linux::fast_thread_clock_init();
4166 // Allocate a single page and mark it as readable for safepoint polling
4167 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4168 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
4170 os::set_polling_page( polling_page );
4172 #ifndef PRODUCT
4173 if(Verbose && PrintMiscellaneous)
4174 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
4175 #endif
4177 if (!UseMembar) {
4178 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
4179 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
4180 os::set_memory_serialize_page( mem_serialize_page );
4182 #ifndef PRODUCT
4183 if(Verbose && PrintMiscellaneous)
4184 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
4185 #endif
4186 }
4188 os::large_page_init();
4190 // initialize suspend/resume support - must do this before signal_sets_init()
4191 if (SR_initialize() != 0) {
4192 perror("SR_initialize failed");
4193 return JNI_ERR;
4194 }
4196 Linux::signal_sets_init();
4197 Linux::install_signal_handlers();
4199 // Check minimum allowable stack size for thread creation and to initialize
4200 // the java system classes, including StackOverflowError - depends on page
4201 // size. Add a page for compiler2 recursion in main thread.
4202 // Add in 2*BytesPerWord times page size to account for VM stack during
4203 // class initialization depending on 32 or 64 bit VM.
4204 os::Linux::min_stack_allowed = MAX2(os::Linux::min_stack_allowed,
4205 (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
4206 2*BytesPerWord COMPILER2_PRESENT(+1)) * Linux::page_size());
4208 size_t threadStackSizeInBytes = ThreadStackSize * K;
4209 if (threadStackSizeInBytes != 0 &&
4210 threadStackSizeInBytes < os::Linux::min_stack_allowed) {
4211 tty->print_cr("\nThe stack size specified is too small, "
4212 "Specify at least %dk",
4213 os::Linux::min_stack_allowed/ K);
4214 return JNI_ERR;
4215 }
4217 // Make the stack size a multiple of the page size so that
4218 // the yellow/red zones can be guarded.
4219 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
4220 vm_page_size()));
4222 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
4224 Linux::libpthread_init();
4225 if (PrintMiscellaneous && (Verbose || WizardMode)) {
4226 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
4227 Linux::glibc_version(), Linux::libpthread_version(),
4228 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
4229 }
4231 if (UseNUMA) {
4232 if (!Linux::libnuma_init()) {
4233 UseNUMA = false;
4234 } else {
4235 if ((Linux::numa_max_node() < 1)) {
4236 // There's only one node(they start from 0), disable NUMA.
4237 UseNUMA = false;
4238 }
4239 }
4240 // With SHM large pages we cannot uncommit a page, so there's not way
4241 // we can make the adaptive lgrp chunk resizing work. If the user specified
4242 // both UseNUMA and UseLargePages (or UseSHM) on the command line - warn and
4243 // disable adaptive resizing.
4244 if (UseNUMA && UseLargePages && UseSHM) {
4245 if (!FLAG_IS_DEFAULT(UseNUMA)) {
4246 if (FLAG_IS_DEFAULT(UseLargePages) && FLAG_IS_DEFAULT(UseSHM)) {
4247 UseLargePages = false;
4248 } else {
4249 warning("UseNUMA is not fully compatible with SHM large pages, disabling adaptive resizing");
4250 UseAdaptiveSizePolicy = false;
4251 UseAdaptiveNUMAChunkSizing = false;
4252 }
4253 } else {
4254 UseNUMA = false;
4255 }
4256 }
4257 if (!UseNUMA && ForceNUMA) {
4258 UseNUMA = true;
4259 }
4260 }
4262 if (MaxFDLimit) {
4263 // set the number of file descriptors to max. print out error
4264 // if getrlimit/setrlimit fails but continue regardless.
4265 struct rlimit nbr_files;
4266 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
4267 if (status != 0) {
4268 if (PrintMiscellaneous && (Verbose || WizardMode))
4269 perror("os::init_2 getrlimit failed");
4270 } else {
4271 nbr_files.rlim_cur = nbr_files.rlim_max;
4272 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
4273 if (status != 0) {
4274 if (PrintMiscellaneous && (Verbose || WizardMode))
4275 perror("os::init_2 setrlimit failed");
4276 }
4277 }
4278 }
4280 // Initialize lock used to serialize thread creation (see os::create_thread)
4281 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
4283 // at-exit methods are called in the reverse order of their registration.
4284 // atexit functions are called on return from main or as a result of a
4285 // call to exit(3C). There can be only 32 of these functions registered
4286 // and atexit() does not set errno.
4288 if (PerfAllowAtExitRegistration) {
4289 // only register atexit functions if PerfAllowAtExitRegistration is set.
4290 // atexit functions can be delayed until process exit time, which
4291 // can be problematic for embedded VM situations. Embedded VMs should
4292 // call DestroyJavaVM() to assure that VM resources are released.
4294 // note: perfMemory_exit_helper atexit function may be removed in
4295 // the future if the appropriate cleanup code can be added to the
4296 // VM_Exit VMOperation's doit method.
4297 if (atexit(perfMemory_exit_helper) != 0) {
4298 warning("os::init2 atexit(perfMemory_exit_helper) failed");
4299 }
4300 }
4302 // initialize thread priority policy
4303 prio_init();
4305 return JNI_OK;
4306 }
4308 // this is called at the end of vm_initialization
4309 void os::init_3(void)
4310 {
4311 #ifdef JAVASE_EMBEDDED
4312 // Start the MemNotifyThread
4313 if (LowMemoryProtection) {
4314 MemNotifyThread::start();
4315 }
4316 return;
4317 #endif
4318 }
4320 // Mark the polling page as unreadable
4321 void os::make_polling_page_unreadable(void) {
4322 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
4323 fatal("Could not disable polling page");
4324 };
4326 // Mark the polling page as readable
4327 void os::make_polling_page_readable(void) {
4328 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
4329 fatal("Could not enable polling page");
4330 }
4331 };
4333 int os::active_processor_count() {
4334 // Linux doesn't yet have a (official) notion of processor sets,
4335 // so just return the number of online processors.
4336 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
4337 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
4338 return online_cpus;
4339 }
4341 void os::set_native_thread_name(const char *name) {
4342 // Not yet implemented.
4343 return;
4344 }
4346 bool os::distribute_processes(uint length, uint* distribution) {
4347 // Not yet implemented.
4348 return false;
4349 }
4351 bool os::bind_to_processor(uint processor_id) {
4352 // Not yet implemented.
4353 return false;
4354 }
4356 ///
4358 // Suspends the target using the signal mechanism and then grabs the PC before
4359 // resuming the target. Used by the flat-profiler only
4360 ExtendedPC os::get_thread_pc(Thread* thread) {
4361 // Make sure that it is called by the watcher for the VMThread
4362 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4363 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4365 ExtendedPC epc;
4367 OSThread* osthread = thread->osthread();
4368 if (do_suspend(osthread)) {
4369 if (osthread->ucontext() != NULL) {
4370 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4371 } else {
4372 // NULL context is unexpected, double-check this is the VMThread
4373 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4374 }
4375 do_resume(osthread);
4376 }
4377 // failure means pthread_kill failed for some reason - arguably this is
4378 // a fatal problem, but such problems are ignored elsewhere
4380 return epc;
4381 }
4383 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4384 {
4385 if (is_NPTL()) {
4386 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4387 } else {
4388 #ifndef IA64
4389 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4390 // word back to default 64bit precision if condvar is signaled. Java
4391 // wants 53bit precision. Save and restore current value.
4392 int fpu = get_fpu_control_word();
4393 #endif // IA64
4394 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4395 #ifndef IA64
4396 set_fpu_control_word(fpu);
4397 #endif // IA64
4398 return status;
4399 }
4400 }
4402 ////////////////////////////////////////////////////////////////////////////////
4403 // debug support
4405 static address same_page(address x, address y) {
4406 int page_bits = -os::vm_page_size();
4407 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4408 return x;
4409 else if (x > y)
4410 return (address)(intptr_t(y) | ~page_bits) + 1;
4411 else
4412 return (address)(intptr_t(y) & page_bits);
4413 }
4415 bool os::find(address addr, outputStream* st) {
4416 Dl_info dlinfo;
4417 memset(&dlinfo, 0, sizeof(dlinfo));
4418 if (dladdr(addr, &dlinfo)) {
4419 st->print(PTR_FORMAT ": ", addr);
4420 if (dlinfo.dli_sname != NULL) {
4421 st->print("%s+%#x", dlinfo.dli_sname,
4422 addr - (intptr_t)dlinfo.dli_saddr);
4423 } else if (dlinfo.dli_fname) {
4424 st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4425 } else {
4426 st->print("<absolute address>");
4427 }
4428 if (dlinfo.dli_fname) {
4429 st->print(" in %s", dlinfo.dli_fname);
4430 }
4431 if (dlinfo.dli_fbase) {
4432 st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4433 }
4434 st->cr();
4436 if (Verbose) {
4437 // decode some bytes around the PC
4438 address begin = same_page(addr-40, addr);
4439 address end = same_page(addr+40, addr);
4440 address lowest = (address) dlinfo.dli_sname;
4441 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4442 if (begin < lowest) begin = lowest;
4443 Dl_info dlinfo2;
4444 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4445 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4446 end = (address) dlinfo2.dli_saddr;
4447 Disassembler::decode(begin, end, st);
4448 }
4449 return true;
4450 }
4451 return false;
4452 }
4454 ////////////////////////////////////////////////////////////////////////////////
4455 // misc
4457 // This does not do anything on Linux. This is basically a hook for being
4458 // able to use structured exception handling (thread-local exception filters)
4459 // on, e.g., Win32.
4460 void
4461 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4462 JavaCallArguments* args, Thread* thread) {
4463 f(value, method, args, thread);
4464 }
4466 void os::print_statistics() {
4467 }
4469 int os::message_box(const char* title, const char* message) {
4470 int i;
4471 fdStream err(defaultStream::error_fd());
4472 for (i = 0; i < 78; i++) err.print_raw("=");
4473 err.cr();
4474 err.print_raw_cr(title);
4475 for (i = 0; i < 78; i++) err.print_raw("-");
4476 err.cr();
4477 err.print_raw_cr(message);
4478 for (i = 0; i < 78; i++) err.print_raw("=");
4479 err.cr();
4481 char buf[16];
4482 // Prevent process from exiting upon "read error" without consuming all CPU
4483 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4485 return buf[0] == 'y' || buf[0] == 'Y';
4486 }
4488 int os::stat(const char *path, struct stat *sbuf) {
4489 char pathbuf[MAX_PATH];
4490 if (strlen(path) > MAX_PATH - 1) {
4491 errno = ENAMETOOLONG;
4492 return -1;
4493 }
4494 os::native_path(strcpy(pathbuf, path));
4495 return ::stat(pathbuf, sbuf);
4496 }
4498 bool os::check_heap(bool force) {
4499 return true;
4500 }
4502 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4503 return ::vsnprintf(buf, count, format, args);
4504 }
4506 // Is a (classpath) directory empty?
4507 bool os::dir_is_empty(const char* path) {
4508 DIR *dir = NULL;
4509 struct dirent *ptr;
4511 dir = opendir(path);
4512 if (dir == NULL) return true;
4514 /* Scan the directory */
4515 bool result = true;
4516 char buf[sizeof(struct dirent) + MAX_PATH];
4517 while (result && (ptr = ::readdir(dir)) != NULL) {
4518 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4519 result = false;
4520 }
4521 }
4522 closedir(dir);
4523 return result;
4524 }
4526 // This code originates from JDK's sysOpen and open64_w
4527 // from src/solaris/hpi/src/system_md.c
4529 #ifndef O_DELETE
4530 #define O_DELETE 0x10000
4531 #endif
4533 // Open a file. Unlink the file immediately after open returns
4534 // if the specified oflag has the O_DELETE flag set.
4535 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
4537 int os::open(const char *path, int oflag, int mode) {
4539 if (strlen(path) > MAX_PATH - 1) {
4540 errno = ENAMETOOLONG;
4541 return -1;
4542 }
4543 int fd;
4544 int o_delete = (oflag & O_DELETE);
4545 oflag = oflag & ~O_DELETE;
4547 fd = ::open64(path, oflag, mode);
4548 if (fd == -1) return -1;
4550 //If the open succeeded, the file might still be a directory
4551 {
4552 struct stat64 buf64;
4553 int ret = ::fstat64(fd, &buf64);
4554 int st_mode = buf64.st_mode;
4556 if (ret != -1) {
4557 if ((st_mode & S_IFMT) == S_IFDIR) {
4558 errno = EISDIR;
4559 ::close(fd);
4560 return -1;
4561 }
4562 } else {
4563 ::close(fd);
4564 return -1;
4565 }
4566 }
4568 /*
4569 * All file descriptors that are opened in the JVM and not
4570 * specifically destined for a subprocess should have the
4571 * close-on-exec flag set. If we don't set it, then careless 3rd
4572 * party native code might fork and exec without closing all
4573 * appropriate file descriptors (e.g. as we do in closeDescriptors in
4574 * UNIXProcess.c), and this in turn might:
4575 *
4576 * - cause end-of-file to fail to be detected on some file
4577 * descriptors, resulting in mysterious hangs, or
4578 *
4579 * - might cause an fopen in the subprocess to fail on a system
4580 * suffering from bug 1085341.
4581 *
4582 * (Yes, the default setting of the close-on-exec flag is a Unix
4583 * design flaw)
4584 *
4585 * See:
4586 * 1085341: 32-bit stdio routines should support file descriptors >255
4587 * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4588 * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4589 */
4590 #ifdef FD_CLOEXEC
4591 {
4592 int flags = ::fcntl(fd, F_GETFD);
4593 if (flags != -1)
4594 ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4595 }
4596 #endif
4598 if (o_delete != 0) {
4599 ::unlink(path);
4600 }
4601 return fd;
4602 }
4605 // create binary file, rewriting existing file if required
4606 int os::create_binary_file(const char* path, bool rewrite_existing) {
4607 int oflags = O_WRONLY | O_CREAT;
4608 if (!rewrite_existing) {
4609 oflags |= O_EXCL;
4610 }
4611 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4612 }
4614 // return current position of file pointer
4615 jlong os::current_file_offset(int fd) {
4616 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4617 }
4619 // move file pointer to the specified offset
4620 jlong os::seek_to_file_offset(int fd, jlong offset) {
4621 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4622 }
4624 // This code originates from JDK's sysAvailable
4625 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4627 int os::available(int fd, jlong *bytes) {
4628 jlong cur, end;
4629 int mode;
4630 struct stat64 buf64;
4632 if (::fstat64(fd, &buf64) >= 0) {
4633 mode = buf64.st_mode;
4634 if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4635 /*
4636 * XXX: is the following call interruptible? If so, this might
4637 * need to go through the INTERRUPT_IO() wrapper as for other
4638 * blocking, interruptible calls in this file.
4639 */
4640 int n;
4641 if (::ioctl(fd, FIONREAD, &n) >= 0) {
4642 *bytes = n;
4643 return 1;
4644 }
4645 }
4646 }
4647 if ((cur = ::lseek64(fd, 0L, SEEK_CUR)) == -1) {
4648 return 0;
4649 } else if ((end = ::lseek64(fd, 0L, SEEK_END)) == -1) {
4650 return 0;
4651 } else if (::lseek64(fd, cur, SEEK_SET) == -1) {
4652 return 0;
4653 }
4654 *bytes = end - cur;
4655 return 1;
4656 }
4658 int os::socket_available(int fd, jint *pbytes) {
4659 // Linux doc says EINTR not returned, unlike Solaris
4660 int ret = ::ioctl(fd, FIONREAD, pbytes);
4662 //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4663 // is expected to return 0 on failure and 1 on success to the jdk.
4664 return (ret < 0) ? 0 : 1;
4665 }
4667 // Map a block of memory.
4668 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
4669 char *addr, size_t bytes, bool read_only,
4670 bool allow_exec) {
4671 int prot;
4672 int flags = MAP_PRIVATE;
4674 if (read_only) {
4675 prot = PROT_READ;
4676 } else {
4677 prot = PROT_READ | PROT_WRITE;
4678 }
4680 if (allow_exec) {
4681 prot |= PROT_EXEC;
4682 }
4684 if (addr != NULL) {
4685 flags |= MAP_FIXED;
4686 }
4688 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4689 fd, file_offset);
4690 if (mapped_address == MAP_FAILED) {
4691 return NULL;
4692 }
4693 return mapped_address;
4694 }
4697 // Remap a block of memory.
4698 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
4699 char *addr, size_t bytes, bool read_only,
4700 bool allow_exec) {
4701 // same as map_memory() on this OS
4702 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4703 allow_exec);
4704 }
4707 // Unmap a block of memory.
4708 bool os::pd_unmap_memory(char* addr, size_t bytes) {
4709 return munmap(addr, bytes) == 0;
4710 }
4712 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4714 static clockid_t thread_cpu_clockid(Thread* thread) {
4715 pthread_t tid = thread->osthread()->pthread_id();
4716 clockid_t clockid;
4718 // Get thread clockid
4719 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4720 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4721 return clockid;
4722 }
4724 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4725 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4726 // of a thread.
4727 //
4728 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4729 // the fast estimate available on the platform.
4731 jlong os::current_thread_cpu_time() {
4732 if (os::Linux::supports_fast_thread_cpu_time()) {
4733 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4734 } else {
4735 // return user + sys since the cost is the same
4736 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4737 }
4738 }
4740 jlong os::thread_cpu_time(Thread* thread) {
4741 // consistent with what current_thread_cpu_time() returns
4742 if (os::Linux::supports_fast_thread_cpu_time()) {
4743 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4744 } else {
4745 return slow_thread_cpu_time(thread, true /* user + sys */);
4746 }
4747 }
4749 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4750 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4751 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4752 } else {
4753 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4754 }
4755 }
4757 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4758 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4759 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4760 } else {
4761 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4762 }
4763 }
4765 //
4766 // -1 on error.
4767 //
4769 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4770 static bool proc_pid_cpu_avail = true;
4771 static bool proc_task_unchecked = true;
4772 static const char *proc_stat_path = "/proc/%d/stat";
4773 pid_t tid = thread->osthread()->thread_id();
4774 int i;
4775 char *s;
4776 char stat[2048];
4777 int statlen;
4778 char proc_name[64];
4779 int count;
4780 long sys_time, user_time;
4781 char string[64];
4782 char cdummy;
4783 int idummy;
4784 long ldummy;
4785 FILE *fp;
4787 // We first try accessing /proc/<pid>/cpu since this is faster to
4788 // process. If this file is not present (linux kernels 2.5 and above)
4789 // then we open /proc/<pid>/stat.
4790 if ( proc_pid_cpu_avail ) {
4791 sprintf(proc_name, "/proc/%d/cpu", tid);
4792 fp = fopen(proc_name, "r");
4793 if ( fp != NULL ) {
4794 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4795 fclose(fp);
4796 if ( count != 3 ) return -1;
4798 if (user_sys_cpu_time) {
4799 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4800 } else {
4801 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4802 }
4803 }
4804 else proc_pid_cpu_avail = false;
4805 }
4807 // The /proc/<tid>/stat aggregates per-process usage on
4808 // new Linux kernels 2.6+ where NPTL is supported.
4809 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4810 // See bug 6328462.
4811 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4812 // and possibly in some other cases, so we check its availability.
4813 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4814 // This is executed only once
4815 proc_task_unchecked = false;
4816 fp = fopen("/proc/self/task", "r");
4817 if (fp != NULL) {
4818 proc_stat_path = "/proc/self/task/%d/stat";
4819 fclose(fp);
4820 }
4821 }
4823 sprintf(proc_name, proc_stat_path, tid);
4824 fp = fopen(proc_name, "r");
4825 if ( fp == NULL ) return -1;
4826 statlen = fread(stat, 1, 2047, fp);
4827 stat[statlen] = '\0';
4828 fclose(fp);
4830 // Skip pid and the command string. Note that we could be dealing with
4831 // weird command names, e.g. user could decide to rename java launcher
4832 // to "java 1.4.2 :)", then the stat file would look like
4833 // 1234 (java 1.4.2 :)) R ... ...
4834 // We don't really need to know the command string, just find the last
4835 // occurrence of ")" and then start parsing from there. See bug 4726580.
4836 s = strrchr(stat, ')');
4837 i = 0;
4838 if (s == NULL ) return -1;
4840 // Skip blank chars
4841 do s++; while (isspace(*s));
4843 count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4844 &cdummy, &idummy, &idummy, &idummy, &idummy, &idummy,
4845 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4846 &user_time, &sys_time);
4847 if ( count != 13 ) return -1;
4848 if (user_sys_cpu_time) {
4849 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4850 } else {
4851 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4852 }
4853 }
4855 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4856 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4857 info_ptr->may_skip_backward = false; // elapsed time not wall time
4858 info_ptr->may_skip_forward = false; // elapsed time not wall time
4859 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4860 }
4862 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4863 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4864 info_ptr->may_skip_backward = false; // elapsed time not wall time
4865 info_ptr->may_skip_forward = false; // elapsed time not wall time
4866 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4867 }
4869 bool os::is_thread_cpu_time_supported() {
4870 return true;
4871 }
4873 // System loadavg support. Returns -1 if load average cannot be obtained.
4874 // Linux doesn't yet have a (official) notion of processor sets,
4875 // so just return the system wide load average.
4876 int os::loadavg(double loadavg[], int nelem) {
4877 return ::getloadavg(loadavg, nelem);
4878 }
4880 void os::pause() {
4881 char filename[MAX_PATH];
4882 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4883 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4884 } else {
4885 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4886 }
4888 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4889 if (fd != -1) {
4890 struct stat buf;
4891 ::close(fd);
4892 while (::stat(filename, &buf) == 0) {
4893 (void)::poll(NULL, 0, 100);
4894 }
4895 } else {
4896 jio_fprintf(stderr,
4897 "Could not open pause file '%s', continuing immediately.\n", filename);
4898 }
4899 }
4902 // Refer to the comments in os_solaris.cpp park-unpark.
4903 //
4904 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4905 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4906 // For specifics regarding the bug see GLIBC BUGID 261237 :
4907 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4908 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4909 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4910 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4911 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4912 // and monitorenter when we're using 1-0 locking. All those operations may result in
4913 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4914 // of libpthread avoids the problem, but isn't practical.
4915 //
4916 // Possible remedies:
4917 //
4918 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4919 // This is palliative and probabilistic, however. If the thread is preempted
4920 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4921 // than the minimum period may have passed, and the abstime may be stale (in the
4922 // past) resultin in a hang. Using this technique reduces the odds of a hang
4923 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4924 //
4925 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4926 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4927 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4928 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4929 // thread.
4930 //
4931 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4932 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4933 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4934 // This also works well. In fact it avoids kernel-level scalability impediments
4935 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4936 // timers in a graceful fashion.
4937 //
4938 // 4. When the abstime value is in the past it appears that control returns
4939 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4940 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4941 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4942 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4943 // It may be possible to avoid reinitialization by checking the return
4944 // value from pthread_cond_timedwait(). In addition to reinitializing the
4945 // condvar we must establish the invariant that cond_signal() is only called
4946 // within critical sections protected by the adjunct mutex. This prevents
4947 // cond_signal() from "seeing" a condvar that's in the midst of being
4948 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4949 // desirable signal-after-unlock optimization that avoids futile context switching.
4950 //
4951 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4952 // structure when a condvar is used or initialized. cond_destroy() would
4953 // release the helper structure. Our reinitialize-after-timedwait fix
4954 // put excessive stress on malloc/free and locks protecting the c-heap.
4955 //
4956 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4957 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4958 // and only enabling the work-around for vulnerable environments.
4960 // utility to compute the abstime argument to timedwait:
4961 // millis is the relative timeout time
4962 // abstime will be the absolute timeout time
4963 // TODO: replace compute_abstime() with unpackTime()
4965 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4966 if (millis < 0) millis = 0;
4967 struct timeval now;
4968 int status = gettimeofday(&now, NULL);
4969 assert(status == 0, "gettimeofday");
4970 jlong seconds = millis / 1000;
4971 millis %= 1000;
4972 if (seconds > 50000000) { // see man cond_timedwait(3T)
4973 seconds = 50000000;
4974 }
4975 abstime->tv_sec = now.tv_sec + seconds;
4976 long usec = now.tv_usec + millis * 1000;
4977 if (usec >= 1000000) {
4978 abstime->tv_sec += 1;
4979 usec -= 1000000;
4980 }
4981 abstime->tv_nsec = usec * 1000;
4982 return abstime;
4983 }
4986 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4987 // Conceptually TryPark() should be equivalent to park(0).
4989 int os::PlatformEvent::TryPark() {
4990 for (;;) {
4991 const int v = _Event ;
4992 guarantee ((v == 0) || (v == 1), "invariant") ;
4993 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4994 }
4995 }
4997 void os::PlatformEvent::park() { // AKA "down()"
4998 // Invariant: Only the thread associated with the Event/PlatformEvent
4999 // may call park().
5000 // TODO: assert that _Assoc != NULL or _Assoc == Self
5001 int v ;
5002 for (;;) {
5003 v = _Event ;
5004 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5005 }
5006 guarantee (v >= 0, "invariant") ;
5007 if (v == 0) {
5008 // Do this the hard way by blocking ...
5009 int status = pthread_mutex_lock(_mutex);
5010 assert_status(status == 0, status, "mutex_lock");
5011 guarantee (_nParked == 0, "invariant") ;
5012 ++ _nParked ;
5013 while (_Event < 0) {
5014 status = pthread_cond_wait(_cond, _mutex);
5015 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
5016 // Treat this the same as if the wait was interrupted
5017 if (status == ETIME) { status = EINTR; }
5018 assert_status(status == 0 || status == EINTR, status, "cond_wait");
5019 }
5020 -- _nParked ;
5022 // In theory we could move the ST of 0 into _Event past the unlock(),
5023 // but then we'd need a MEMBAR after the ST.
5024 _Event = 0 ;
5025 status = pthread_mutex_unlock(_mutex);
5026 assert_status(status == 0, status, "mutex_unlock");
5027 }
5028 guarantee (_Event >= 0, "invariant") ;
5029 }
5031 int os::PlatformEvent::park(jlong millis) {
5032 guarantee (_nParked == 0, "invariant") ;
5034 int v ;
5035 for (;;) {
5036 v = _Event ;
5037 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
5038 }
5039 guarantee (v >= 0, "invariant") ;
5040 if (v != 0) return OS_OK ;
5042 // We do this the hard way, by blocking the thread.
5043 // Consider enforcing a minimum timeout value.
5044 struct timespec abst;
5045 compute_abstime(&abst, millis);
5047 int ret = OS_TIMEOUT;
5048 int status = pthread_mutex_lock(_mutex);
5049 assert_status(status == 0, status, "mutex_lock");
5050 guarantee (_nParked == 0, "invariant") ;
5051 ++_nParked ;
5053 // Object.wait(timo) will return because of
5054 // (a) notification
5055 // (b) timeout
5056 // (c) thread.interrupt
5057 //
5058 // Thread.interrupt and object.notify{All} both call Event::set.
5059 // That is, we treat thread.interrupt as a special case of notification.
5060 // The underlying Solaris implementation, cond_timedwait, admits
5061 // spurious/premature wakeups, but the JLS/JVM spec prevents the
5062 // JVM from making those visible to Java code. As such, we must
5063 // filter out spurious wakeups. We assume all ETIME returns are valid.
5064 //
5065 // TODO: properly differentiate simultaneous notify+interrupt.
5066 // In that case, we should propagate the notify to another waiter.
5068 while (_Event < 0) {
5069 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
5070 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5071 pthread_cond_destroy (_cond);
5072 pthread_cond_init (_cond, NULL) ;
5073 }
5074 assert_status(status == 0 || status == EINTR ||
5075 status == ETIME || status == ETIMEDOUT,
5076 status, "cond_timedwait");
5077 if (!FilterSpuriousWakeups) break ; // previous semantics
5078 if (status == ETIME || status == ETIMEDOUT) break ;
5079 // We consume and ignore EINTR and spurious wakeups.
5080 }
5081 --_nParked ;
5082 if (_Event >= 0) {
5083 ret = OS_OK;
5084 }
5085 _Event = 0 ;
5086 status = pthread_mutex_unlock(_mutex);
5087 assert_status(status == 0, status, "mutex_unlock");
5088 assert (_nParked == 0, "invariant") ;
5089 return ret;
5090 }
5092 void os::PlatformEvent::unpark() {
5093 int v, AnyWaiters ;
5094 for (;;) {
5095 v = _Event ;
5096 if (v > 0) {
5097 // The LD of _Event could have reordered or be satisfied
5098 // by a read-aside from this processor's write buffer.
5099 // To avoid problems execute a barrier and then
5100 // ratify the value.
5101 OrderAccess::fence() ;
5102 if (_Event == v) return ;
5103 continue ;
5104 }
5105 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
5106 }
5107 if (v < 0) {
5108 // Wait for the thread associated with the event to vacate
5109 int status = pthread_mutex_lock(_mutex);
5110 assert_status(status == 0, status, "mutex_lock");
5111 AnyWaiters = _nParked ;
5112 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
5113 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
5114 AnyWaiters = 0 ;
5115 pthread_cond_signal (_cond);
5116 }
5117 status = pthread_mutex_unlock(_mutex);
5118 assert_status(status == 0, status, "mutex_unlock");
5119 if (AnyWaiters != 0) {
5120 status = pthread_cond_signal(_cond);
5121 assert_status(status == 0, status, "cond_signal");
5122 }
5123 }
5125 // Note that we signal() _after dropping the lock for "immortal" Events.
5126 // This is safe and avoids a common class of futile wakeups. In rare
5127 // circumstances this can cause a thread to return prematurely from
5128 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
5129 // simply re-test the condition and re-park itself.
5130 }
5133 // JSR166
5134 // -------------------------------------------------------
5136 /*
5137 * The solaris and linux implementations of park/unpark are fairly
5138 * conservative for now, but can be improved. They currently use a
5139 * mutex/condvar pair, plus a a count.
5140 * Park decrements count if > 0, else does a condvar wait. Unpark
5141 * sets count to 1 and signals condvar. Only one thread ever waits
5142 * on the condvar. Contention seen when trying to park implies that someone
5143 * is unparking you, so don't wait. And spurious returns are fine, so there
5144 * is no need to track notifications.
5145 */
5147 #define MAX_SECS 100000000
5148 /*
5149 * This code is common to linux and solaris and will be moved to a
5150 * common place in dolphin.
5151 *
5152 * The passed in time value is either a relative time in nanoseconds
5153 * or an absolute time in milliseconds. Either way it has to be unpacked
5154 * into suitable seconds and nanoseconds components and stored in the
5155 * given timespec structure.
5156 * Given time is a 64-bit value and the time_t used in the timespec is only
5157 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
5158 * overflow if times way in the future are given. Further on Solaris versions
5159 * prior to 10 there is a restriction (see cond_timedwait) that the specified
5160 * number of seconds, in abstime, is less than current_time + 100,000,000.
5161 * As it will be 28 years before "now + 100000000" will overflow we can
5162 * ignore overflow and just impose a hard-limit on seconds using the value
5163 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
5164 * years from "now".
5165 */
5167 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
5168 assert (time > 0, "convertTime");
5170 struct timeval now;
5171 int status = gettimeofday(&now, NULL);
5172 assert(status == 0, "gettimeofday");
5174 time_t max_secs = now.tv_sec + MAX_SECS;
5176 if (isAbsolute) {
5177 jlong secs = time / 1000;
5178 if (secs > max_secs) {
5179 absTime->tv_sec = max_secs;
5180 }
5181 else {
5182 absTime->tv_sec = secs;
5183 }
5184 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
5185 }
5186 else {
5187 jlong secs = time / NANOSECS_PER_SEC;
5188 if (secs >= MAX_SECS) {
5189 absTime->tv_sec = max_secs;
5190 absTime->tv_nsec = 0;
5191 }
5192 else {
5193 absTime->tv_sec = now.tv_sec + secs;
5194 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
5195 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
5196 absTime->tv_nsec -= NANOSECS_PER_SEC;
5197 ++absTime->tv_sec; // note: this must be <= max_secs
5198 }
5199 }
5200 }
5201 assert(absTime->tv_sec >= 0, "tv_sec < 0");
5202 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
5203 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
5204 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
5205 }
5207 void Parker::park(bool isAbsolute, jlong time) {
5208 // Optional fast-path check:
5209 // Return immediately if a permit is available.
5210 if (_counter > 0) {
5211 _counter = 0 ;
5212 OrderAccess::fence();
5213 return ;
5214 }
5216 Thread* thread = Thread::current();
5217 assert(thread->is_Java_thread(), "Must be JavaThread");
5218 JavaThread *jt = (JavaThread *)thread;
5220 // Optional optimization -- avoid state transitions if there's an interrupt pending.
5221 // Check interrupt before trying to wait
5222 if (Thread::is_interrupted(thread, false)) {
5223 return;
5224 }
5226 // Next, demultiplex/decode time arguments
5227 timespec absTime;
5228 if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
5229 return;
5230 }
5231 if (time > 0) {
5232 unpackTime(&absTime, isAbsolute, time);
5233 }
5236 // Enter safepoint region
5237 // Beware of deadlocks such as 6317397.
5238 // The per-thread Parker:: mutex is a classic leaf-lock.
5239 // In particular a thread must never block on the Threads_lock while
5240 // holding the Parker:: mutex. If safepoints are pending both the
5241 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
5242 ThreadBlockInVM tbivm(jt);
5244 // Don't wait if cannot get lock since interference arises from
5245 // unblocking. Also. check interrupt before trying wait
5246 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
5247 return;
5248 }
5250 int status ;
5251 if (_counter > 0) { // no wait needed
5252 _counter = 0;
5253 status = pthread_mutex_unlock(_mutex);
5254 assert (status == 0, "invariant") ;
5255 OrderAccess::fence();
5256 return;
5257 }
5259 #ifdef ASSERT
5260 // Don't catch signals while blocked; let the running threads have the signals.
5261 // (This allows a debugger to break into the running thread.)
5262 sigset_t oldsigs;
5263 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
5264 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
5265 #endif
5267 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
5268 jt->set_suspend_equivalent();
5269 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
5271 if (time == 0) {
5272 status = pthread_cond_wait (_cond, _mutex) ;
5273 } else {
5274 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
5275 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
5276 pthread_cond_destroy (_cond) ;
5277 pthread_cond_init (_cond, NULL);
5278 }
5279 }
5280 assert_status(status == 0 || status == EINTR ||
5281 status == ETIME || status == ETIMEDOUT,
5282 status, "cond_timedwait");
5284 #ifdef ASSERT
5285 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
5286 #endif
5288 _counter = 0 ;
5289 status = pthread_mutex_unlock(_mutex) ;
5290 assert_status(status == 0, status, "invariant") ;
5291 // If externally suspended while waiting, re-suspend
5292 if (jt->handle_special_suspend_equivalent_condition()) {
5293 jt->java_suspend_self();
5294 }
5296 OrderAccess::fence();
5297 }
5299 void Parker::unpark() {
5300 int s, status ;
5301 status = pthread_mutex_lock(_mutex);
5302 assert (status == 0, "invariant") ;
5303 s = _counter;
5304 _counter = 1;
5305 if (s < 1) {
5306 if (WorkAroundNPTLTimedWaitHang) {
5307 status = pthread_cond_signal (_cond) ;
5308 assert (status == 0, "invariant") ;
5309 status = pthread_mutex_unlock(_mutex);
5310 assert (status == 0, "invariant") ;
5311 } else {
5312 status = pthread_mutex_unlock(_mutex);
5313 assert (status == 0, "invariant") ;
5314 status = pthread_cond_signal (_cond) ;
5315 assert (status == 0, "invariant") ;
5316 }
5317 } else {
5318 pthread_mutex_unlock(_mutex);
5319 assert (status == 0, "invariant") ;
5320 }
5321 }
5324 extern char** environ;
5326 #ifndef __NR_fork
5327 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
5328 #endif
5330 #ifndef __NR_execve
5331 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
5332 #endif
5334 // Run the specified command in a separate process. Return its exit value,
5335 // or -1 on failure (e.g. can't fork a new process).
5336 // Unlike system(), this function can be called from signal handler. It
5337 // doesn't block SIGINT et al.
5338 int os::fork_and_exec(char* cmd) {
5339 const char * argv[4] = {"sh", "-c", cmd, NULL};
5341 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
5342 // pthread_atfork handlers and reset pthread library. All we need is a
5343 // separate process to execve. Make a direct syscall to fork process.
5344 // On IA64 there's no fork syscall, we have to use fork() and hope for
5345 // the best...
5346 pid_t pid = NOT_IA64(syscall(__NR_fork);)
5347 IA64_ONLY(fork();)
5349 if (pid < 0) {
5350 // fork failed
5351 return -1;
5353 } else if (pid == 0) {
5354 // child process
5356 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
5357 // first to kill every thread on the thread list. Because this list is
5358 // not reset by fork() (see notes above), execve() will instead kill
5359 // every thread in the parent process. We know this is the only thread
5360 // in the new process, so make a system call directly.
5361 // IA64 should use normal execve() from glibc to match the glibc fork()
5362 // above.
5363 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
5364 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
5366 // execve failed
5367 _exit(-1);
5369 } else {
5370 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
5371 // care about the actual exit code, for now.
5373 int status;
5375 // Wait for the child process to exit. This returns immediately if
5376 // the child has already exited. */
5377 while (waitpid(pid, &status, 0) < 0) {
5378 switch (errno) {
5379 case ECHILD: return 0;
5380 case EINTR: break;
5381 default: return -1;
5382 }
5383 }
5385 if (WIFEXITED(status)) {
5386 // The child exited normally; get its exit code.
5387 return WEXITSTATUS(status);
5388 } else if (WIFSIGNALED(status)) {
5389 // The child exited because of a signal
5390 // The best value to return is 0x80 + signal number,
5391 // because that is what all Unix shells do, and because
5392 // it allows callers to distinguish between process exit and
5393 // process death by signal.
5394 return 0x80 + WTERMSIG(status);
5395 } else {
5396 // Unknown exit code; pass it through
5397 return status;
5398 }
5399 }
5400 }
5402 // is_headless_jre()
5403 //
5404 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
5405 // in order to report if we are running in a headless jre
5406 //
5407 // Since JDK8 xawt/libmawt.so was moved into the same directory
5408 // as libawt.so, and renamed libawt_xawt.so
5409 //
5410 bool os::is_headless_jre() {
5411 struct stat statbuf;
5412 char buf[MAXPATHLEN];
5413 char libmawtpath[MAXPATHLEN];
5414 const char *xawtstr = "/xawt/libmawt.so";
5415 const char *new_xawtstr = "/libawt_xawt.so";
5416 char *p;
5418 // Get path to libjvm.so
5419 os::jvm_path(buf, sizeof(buf));
5421 // Get rid of libjvm.so
5422 p = strrchr(buf, '/');
5423 if (p == NULL) return false;
5424 else *p = '\0';
5426 // Get rid of client or server
5427 p = strrchr(buf, '/');
5428 if (p == NULL) return false;
5429 else *p = '\0';
5431 // check xawt/libmawt.so
5432 strcpy(libmawtpath, buf);
5433 strcat(libmawtpath, xawtstr);
5434 if (::stat(libmawtpath, &statbuf) == 0) return false;
5436 // check libawt_xawt.so
5437 strcpy(libmawtpath, buf);
5438 strcat(libmawtpath, new_xawtstr);
5439 if (::stat(libmawtpath, &statbuf) == 0) return false;
5441 return true;
5442 }
5444 // Get the default path to the core file
5445 // Returns the length of the string
5446 int os::get_core_path(char* buffer, size_t bufferSize) {
5447 const char* p = get_current_directory(buffer, bufferSize);
5449 if (p == NULL) {
5450 assert(p != NULL, "failed to get current directory");
5451 return 0;
5452 }
5454 return strlen(buffer);
5455 }
5457 #ifdef JAVASE_EMBEDDED
5458 //
5459 // A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
5460 //
5461 MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
5463 // ctor
5464 //
5465 MemNotifyThread::MemNotifyThread(int fd): Thread() {
5466 assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
5467 _fd = fd;
5469 if (os::create_thread(this, os::os_thread)) {
5470 _memnotify_thread = this;
5471 os::set_priority(this, NearMaxPriority);
5472 os::start_thread(this);
5473 }
5474 }
5476 // Where all the work gets done
5477 //
5478 void MemNotifyThread::run() {
5479 assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
5481 // Set up the select arguments
5482 fd_set rfds;
5483 if (_fd != -1) {
5484 FD_ZERO(&rfds);
5485 FD_SET(_fd, &rfds);
5486 }
5488 // Now wait for the mem_notify device to wake up
5489 while (1) {
5490 // Wait for the mem_notify device to signal us..
5491 int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
5492 if (rc == -1) {
5493 perror("select!\n");
5494 break;
5495 } else if (rc) {
5496 //ssize_t free_before = os::available_memory();
5497 //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
5499 // The kernel is telling us there is not much memory left...
5500 // try to do something about that
5502 // If we are not already in a GC, try one.
5503 if (!Universe::heap()->is_gc_active()) {
5504 Universe::heap()->collect(GCCause::_allocation_failure);
5506 //ssize_t free_after = os::available_memory();
5507 //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
5508 //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
5509 }
5510 // We might want to do something like the following if we find the GC's are not helping...
5511 // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
5512 }
5513 }
5514 }
5516 //
5517 // See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
5518 //
5519 void MemNotifyThread::start() {
5520 int fd;
5521 fd = open ("/dev/mem_notify", O_RDONLY, 0);
5522 if (fd < 0) {
5523 return;
5524 }
5526 if (memnotify_thread() == NULL) {
5527 new MemNotifyThread(fd);
5528 }
5529 }
5530 #endif // JAVASE_EMBEDDED