Wed, 17 Jul 2013 13:48:15 +0200
8020701: Avoid crashes in WatcherThread
Reviewed-by: acorn, dcubed, dsimms
1 /*
2 * Copyright (c) 1997, 2013, 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 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/icBuffer.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "gc_implementation/shared/vmGCOperations.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "memory/allocation.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "prims/jvm.h"
37 #include "prims/jvm_misc.hpp"
38 #include "prims/privilegedStack.hpp"
39 #include "runtime/arguments.hpp"
40 #include "runtime/frame.inline.hpp"
41 #include "runtime/interfaceSupport.hpp"
42 #include "runtime/java.hpp"
43 #include "runtime/javaCalls.hpp"
44 #include "runtime/mutexLocker.hpp"
45 #include "runtime/os.hpp"
46 #include "runtime/stubRoutines.hpp"
47 #include "runtime/thread.inline.hpp"
48 #include "services/attachListener.hpp"
49 #include "services/memTracker.hpp"
50 #include "services/threadService.hpp"
51 #include "utilities/defaultStream.hpp"
52 #include "utilities/events.hpp"
53 #ifdef TARGET_OS_FAMILY_linux
54 # include "os_linux.inline.hpp"
55 #endif
56 #ifdef TARGET_OS_FAMILY_solaris
57 # include "os_solaris.inline.hpp"
58 #endif
59 #ifdef TARGET_OS_FAMILY_windows
60 # include "os_windows.inline.hpp"
61 #endif
62 #ifdef TARGET_OS_FAMILY_bsd
63 # include "os_bsd.inline.hpp"
64 #endif
66 # include <signal.h>
68 OSThread* os::_starting_thread = NULL;
69 address os::_polling_page = NULL;
70 volatile int32_t* os::_mem_serialize_page = NULL;
71 uintptr_t os::_serialize_page_mask = 0;
72 long os::_rand_seed = 1;
73 int os::_processor_count = 0;
74 size_t os::_page_sizes[os::page_sizes_max];
76 #ifndef PRODUCT
77 julong os::num_mallocs = 0; // # of calls to malloc/realloc
78 julong os::alloc_bytes = 0; // # of bytes allocated
79 julong os::num_frees = 0; // # of calls to free
80 julong os::free_bytes = 0; // # of bytes freed
81 #endif
83 static juint cur_malloc_words = 0; // current size for MallocMaxTestWords
85 void os_init_globals() {
86 // Called from init_globals().
87 // See Threads::create_vm() in thread.cpp, and init.cpp.
88 os::init_globals();
89 }
91 // Fill in buffer with current local time as an ISO-8601 string.
92 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
93 // Returns buffer, or NULL if it failed.
94 // This would mostly be a call to
95 // strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
96 // except that on Windows the %z behaves badly, so we do it ourselves.
97 // Also, people wanted milliseconds on there,
98 // and strftime doesn't do milliseconds.
99 char* os::iso8601_time(char* buffer, size_t buffer_length) {
100 // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
101 // 1 2
102 // 12345678901234567890123456789
103 static const char* iso8601_format =
104 "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d";
105 static const size_t needed_buffer = 29;
107 // Sanity check the arguments
108 if (buffer == NULL) {
109 assert(false, "NULL buffer");
110 return NULL;
111 }
112 if (buffer_length < needed_buffer) {
113 assert(false, "buffer_length too small");
114 return NULL;
115 }
116 // Get the current time
117 jlong milliseconds_since_19700101 = javaTimeMillis();
118 const int milliseconds_per_microsecond = 1000;
119 const time_t seconds_since_19700101 =
120 milliseconds_since_19700101 / milliseconds_per_microsecond;
121 const int milliseconds_after_second =
122 milliseconds_since_19700101 % milliseconds_per_microsecond;
123 // Convert the time value to a tm and timezone variable
124 struct tm time_struct;
125 if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
126 assert(false, "Failed localtime_pd");
127 return NULL;
128 }
129 #if defined(_ALLBSD_SOURCE)
130 const time_t zone = (time_t) time_struct.tm_gmtoff;
131 #else
132 const time_t zone = timezone;
133 #endif
135 // If daylight savings time is in effect,
136 // we are 1 hour East of our time zone
137 const time_t seconds_per_minute = 60;
138 const time_t minutes_per_hour = 60;
139 const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
140 time_t UTC_to_local = zone;
141 if (time_struct.tm_isdst > 0) {
142 UTC_to_local = UTC_to_local - seconds_per_hour;
143 }
144 // Compute the time zone offset.
145 // localtime_pd() sets timezone to the difference (in seconds)
146 // between UTC and and local time.
147 // ISO 8601 says we need the difference between local time and UTC,
148 // we change the sign of the localtime_pd() result.
149 const time_t local_to_UTC = -(UTC_to_local);
150 // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
151 char sign_local_to_UTC = '+';
152 time_t abs_local_to_UTC = local_to_UTC;
153 if (local_to_UTC < 0) {
154 sign_local_to_UTC = '-';
155 abs_local_to_UTC = -(abs_local_to_UTC);
156 }
157 // Convert time zone offset seconds to hours and minutes.
158 const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
159 const time_t zone_min =
160 ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
162 // Print an ISO 8601 date and time stamp into the buffer
163 const int year = 1900 + time_struct.tm_year;
164 const int month = 1 + time_struct.tm_mon;
165 const int printed = jio_snprintf(buffer, buffer_length, iso8601_format,
166 year,
167 month,
168 time_struct.tm_mday,
169 time_struct.tm_hour,
170 time_struct.tm_min,
171 time_struct.tm_sec,
172 milliseconds_after_second,
173 sign_local_to_UTC,
174 zone_hours,
175 zone_min);
176 if (printed == 0) {
177 assert(false, "Failed jio_printf");
178 return NULL;
179 }
180 return buffer;
181 }
183 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
184 #ifdef ASSERT
185 if (!(!thread->is_Java_thread() ||
186 Thread::current() == thread ||
187 Threads_lock->owned_by_self()
188 || thread->is_Compiler_thread()
189 )) {
190 assert(false, "possibility of dangling Thread pointer");
191 }
192 #endif
194 if (p >= MinPriority && p <= MaxPriority) {
195 int priority = java_to_os_priority[p];
196 return set_native_priority(thread, priority);
197 } else {
198 assert(false, "Should not happen");
199 return OS_ERR;
200 }
201 }
203 // The mapping from OS priority back to Java priority may be inexact because
204 // Java priorities can map M:1 with native priorities. If you want the definite
205 // Java priority then use JavaThread::java_priority()
206 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
207 int p;
208 int os_prio;
209 OSReturn ret = get_native_priority(thread, &os_prio);
210 if (ret != OS_OK) return ret;
212 if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
213 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
214 } else {
215 // niceness values are in reverse order
216 for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
217 }
218 priority = (ThreadPriority)p;
219 return OS_OK;
220 }
223 // --------------------- sun.misc.Signal (optional) ---------------------
226 // SIGBREAK is sent by the keyboard to query the VM state
227 #ifndef SIGBREAK
228 #define SIGBREAK SIGQUIT
229 #endif
231 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
234 static void signal_thread_entry(JavaThread* thread, TRAPS) {
235 os::set_priority(thread, NearMaxPriority);
236 while (true) {
237 int sig;
238 {
239 // FIXME : Currently we have not decieded what should be the status
240 // for this java thread blocked here. Once we decide about
241 // that we should fix this.
242 sig = os::signal_wait();
243 }
244 if (sig == os::sigexitnum_pd()) {
245 // Terminate the signal thread
246 return;
247 }
249 switch (sig) {
250 case SIGBREAK: {
251 // Check if the signal is a trigger to start the Attach Listener - in that
252 // case don't print stack traces.
253 if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
254 continue;
255 }
256 // Print stack traces
257 // Any SIGBREAK operations added here should make sure to flush
258 // the output stream (e.g. tty->flush()) after output. See 4803766.
259 // Each module also prints an extra carriage return after its output.
260 VM_PrintThreads op;
261 VMThread::execute(&op);
262 VM_PrintJNI jni_op;
263 VMThread::execute(&jni_op);
264 VM_FindDeadlocks op1(tty);
265 VMThread::execute(&op1);
266 Universe::print_heap_at_SIGBREAK();
267 if (PrintClassHistogram) {
268 VM_GC_HeapInspection op1(gclog_or_tty, true /* force full GC before heap inspection */);
269 VMThread::execute(&op1);
270 }
271 if (JvmtiExport::should_post_data_dump()) {
272 JvmtiExport::post_data_dump();
273 }
274 break;
275 }
276 default: {
277 // Dispatch the signal to java
278 HandleMark hm(THREAD);
279 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_Signal(), THREAD);
280 KlassHandle klass (THREAD, k);
281 if (klass.not_null()) {
282 JavaValue result(T_VOID);
283 JavaCallArguments args;
284 args.push_int(sig);
285 JavaCalls::call_static(
286 &result,
287 klass,
288 vmSymbols::dispatch_name(),
289 vmSymbols::int_void_signature(),
290 &args,
291 THREAD
292 );
293 }
294 if (HAS_PENDING_EXCEPTION) {
295 // tty is initialized early so we don't expect it to be null, but
296 // if it is we can't risk doing an initialization that might
297 // trigger additional out-of-memory conditions
298 if (tty != NULL) {
299 char klass_name[256];
300 char tmp_sig_name[16];
301 const char* sig_name = "UNKNOWN";
302 InstanceKlass::cast(PENDING_EXCEPTION->klass())->
303 name()->as_klass_external_name(klass_name, 256);
304 if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
305 sig_name = tmp_sig_name;
306 warning("Exception %s occurred dispatching signal %s to handler"
307 "- the VM may need to be forcibly terminated",
308 klass_name, sig_name );
309 }
310 CLEAR_PENDING_EXCEPTION;
311 }
312 }
313 }
314 }
315 }
318 void os::signal_init() {
319 if (!ReduceSignalUsage) {
320 // Setup JavaThread for processing signals
321 EXCEPTION_MARK;
322 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
323 instanceKlassHandle klass (THREAD, k);
324 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
326 const char thread_name[] = "Signal Dispatcher";
327 Handle string = java_lang_String::create_from_str(thread_name, CHECK);
329 // Initialize thread_oop to put it into the system threadGroup
330 Handle thread_group (THREAD, Universe::system_thread_group());
331 JavaValue result(T_VOID);
332 JavaCalls::call_special(&result, thread_oop,
333 klass,
334 vmSymbols::object_initializer_name(),
335 vmSymbols::threadgroup_string_void_signature(),
336 thread_group,
337 string,
338 CHECK);
340 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
341 JavaCalls::call_special(&result,
342 thread_group,
343 group,
344 vmSymbols::add_method_name(),
345 vmSymbols::thread_void_signature(),
346 thread_oop, // ARG 1
347 CHECK);
349 os::signal_init_pd();
351 { MutexLocker mu(Threads_lock);
352 JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
354 // At this point it may be possible that no osthread was created for the
355 // JavaThread due to lack of memory. We would have to throw an exception
356 // in that case. However, since this must work and we do not allow
357 // exceptions anyway, check and abort if this fails.
358 if (signal_thread == NULL || signal_thread->osthread() == NULL) {
359 vm_exit_during_initialization("java.lang.OutOfMemoryError",
360 "unable to create new native thread");
361 }
363 java_lang_Thread::set_thread(thread_oop(), signal_thread);
364 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
365 java_lang_Thread::set_daemon(thread_oop());
367 signal_thread->set_threadObj(thread_oop());
368 Threads::add(signal_thread);
369 Thread::start(signal_thread);
370 }
371 // Handle ^BREAK
372 os::signal(SIGBREAK, os::user_handler());
373 }
374 }
377 void os::terminate_signal_thread() {
378 if (!ReduceSignalUsage)
379 signal_notify(sigexitnum_pd());
380 }
383 // --------------------- loading libraries ---------------------
385 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
386 extern struct JavaVM_ main_vm;
388 static void* _native_java_library = NULL;
390 void* os::native_java_library() {
391 if (_native_java_library == NULL) {
392 char buffer[JVM_MAXPATHLEN];
393 char ebuf[1024];
395 // Try to load verify dll first. In 1.3 java dll depends on it and is not
396 // always able to find it when the loading executable is outside the JDK.
397 // In order to keep working with 1.2 we ignore any loading errors.
398 if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
399 "verify")) {
400 dll_load(buffer, ebuf, sizeof(ebuf));
401 }
403 // Load java dll
404 if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
405 "java")) {
406 _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
407 }
408 if (_native_java_library == NULL) {
409 vm_exit_during_initialization("Unable to load native library", ebuf);
410 }
412 #if defined(__OpenBSD__)
413 // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
414 // ignore errors
415 if (dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
416 "net")) {
417 dll_load(buffer, ebuf, sizeof(ebuf));
418 }
419 #endif
420 }
421 static jboolean onLoaded = JNI_FALSE;
422 if (onLoaded) {
423 // We may have to wait to fire OnLoad until TLS is initialized.
424 if (ThreadLocalStorage::is_initialized()) {
425 // The JNI_OnLoad handling is normally done by method load in
426 // java.lang.ClassLoader$NativeLibrary, but the VM loads the base library
427 // explicitly so we have to check for JNI_OnLoad as well
428 const char *onLoadSymbols[] = JNI_ONLOAD_SYMBOLS;
429 JNI_OnLoad_t JNI_OnLoad = CAST_TO_FN_PTR(
430 JNI_OnLoad_t, dll_lookup(_native_java_library, onLoadSymbols[0]));
431 if (JNI_OnLoad != NULL) {
432 JavaThread* thread = JavaThread::current();
433 ThreadToNativeFromVM ttn(thread);
434 HandleMark hm(thread);
435 jint ver = (*JNI_OnLoad)(&main_vm, NULL);
436 onLoaded = JNI_TRUE;
437 if (!Threads::is_supported_jni_version_including_1_1(ver)) {
438 vm_exit_during_initialization("Unsupported JNI version");
439 }
440 }
441 }
442 }
443 return _native_java_library;
444 }
446 // --------------------- heap allocation utilities ---------------------
448 char *os::strdup(const char *str, MEMFLAGS flags) {
449 size_t size = strlen(str);
450 char *dup_str = (char *)malloc(size + 1, flags);
451 if (dup_str == NULL) return NULL;
452 strcpy(dup_str, str);
453 return dup_str;
454 }
458 #ifdef ASSERT
459 #define space_before (MallocCushion + sizeof(double))
460 #define space_after MallocCushion
461 #define size_addr_from_base(p) (size_t*)(p + space_before - sizeof(size_t))
462 #define size_addr_from_obj(p) ((size_t*)p - 1)
463 // MallocCushion: size of extra cushion allocated around objects with +UseMallocOnly
464 // NB: cannot be debug variable, because these aren't set from the command line until
465 // *after* the first few allocs already happened
466 #define MallocCushion 16
467 #else
468 #define space_before 0
469 #define space_after 0
470 #define size_addr_from_base(p) should not use w/o ASSERT
471 #define size_addr_from_obj(p) should not use w/o ASSERT
472 #define MallocCushion 0
473 #endif
474 #define paranoid 0 /* only set to 1 if you suspect checking code has bug */
476 #ifdef ASSERT
477 inline size_t get_size(void* obj) {
478 size_t size = *size_addr_from_obj(obj);
479 if (size < 0) {
480 fatal(err_msg("free: size field of object #" PTR_FORMAT " was overwritten ("
481 SIZE_FORMAT ")", obj, size));
482 }
483 return size;
484 }
486 u_char* find_cushion_backwards(u_char* start) {
487 u_char* p = start;
488 while (p[ 0] != badResourceValue || p[-1] != badResourceValue ||
489 p[-2] != badResourceValue || p[-3] != badResourceValue) p--;
490 // ok, we have four consecutive marker bytes; find start
491 u_char* q = p - 4;
492 while (*q == badResourceValue) q--;
493 return q + 1;
494 }
496 u_char* find_cushion_forwards(u_char* start) {
497 u_char* p = start;
498 while (p[0] != badResourceValue || p[1] != badResourceValue ||
499 p[2] != badResourceValue || p[3] != badResourceValue) p++;
500 // ok, we have four consecutive marker bytes; find end of cushion
501 u_char* q = p + 4;
502 while (*q == badResourceValue) q++;
503 return q - MallocCushion;
504 }
506 void print_neighbor_blocks(void* ptr) {
507 // find block allocated before ptr (not entirely crash-proof)
508 if (MallocCushion < 4) {
509 tty->print_cr("### cannot find previous block (MallocCushion < 4)");
510 return;
511 }
512 u_char* start_of_this_block = (u_char*)ptr - space_before;
513 u_char* end_of_prev_block_data = start_of_this_block - space_after -1;
514 // look for cushion in front of prev. block
515 u_char* start_of_prev_block = find_cushion_backwards(end_of_prev_block_data);
516 ptrdiff_t size = *size_addr_from_base(start_of_prev_block);
517 u_char* obj = start_of_prev_block + space_before;
518 if (size <= 0 ) {
519 // start is bad; mayhave been confused by OS data inbetween objects
520 // search one more backwards
521 start_of_prev_block = find_cushion_backwards(start_of_prev_block);
522 size = *size_addr_from_base(start_of_prev_block);
523 obj = start_of_prev_block + space_before;
524 }
526 if (start_of_prev_block + space_before + size + space_after == start_of_this_block) {
527 tty->print_cr("### previous object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
528 } else {
529 tty->print_cr("### previous object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", obj, size);
530 }
532 // now find successor block
533 u_char* start_of_next_block = (u_char*)ptr + *size_addr_from_obj(ptr) + space_after;
534 start_of_next_block = find_cushion_forwards(start_of_next_block);
535 u_char* next_obj = start_of_next_block + space_before;
536 ptrdiff_t next_size = *size_addr_from_base(start_of_next_block);
537 if (start_of_next_block[0] == badResourceValue &&
538 start_of_next_block[1] == badResourceValue &&
539 start_of_next_block[2] == badResourceValue &&
540 start_of_next_block[3] == badResourceValue) {
541 tty->print_cr("### next object: " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
542 } else {
543 tty->print_cr("### next object (not sure if correct): " PTR_FORMAT " (" SSIZE_FORMAT " bytes)", next_obj, next_size);
544 }
545 }
548 void report_heap_error(void* memblock, void* bad, const char* where) {
549 tty->print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
550 tty->print_cr("## memory stomp: byte at " PTR_FORMAT " %s object " PTR_FORMAT, bad, where, memblock);
551 print_neighbor_blocks(memblock);
552 fatal("memory stomping error");
553 }
555 void verify_block(void* memblock) {
556 size_t size = get_size(memblock);
557 if (MallocCushion) {
558 u_char* ptr = (u_char*)memblock - space_before;
559 for (int i = 0; i < MallocCushion; i++) {
560 if (ptr[i] != badResourceValue) {
561 report_heap_error(memblock, ptr+i, "in front of");
562 }
563 }
564 u_char* end = (u_char*)memblock + size + space_after;
565 for (int j = -MallocCushion; j < 0; j++) {
566 if (end[j] != badResourceValue) {
567 report_heap_error(memblock, end+j, "after");
568 }
569 }
570 }
571 }
572 #endif
574 //
575 // This function supports testing of the malloc out of memory
576 // condition without really running the system out of memory.
577 //
578 static u_char* testMalloc(size_t alloc_size) {
579 assert(MallocMaxTestWords > 0, "sanity check");
581 if ((cur_malloc_words + (alloc_size / BytesPerWord)) > MallocMaxTestWords) {
582 return NULL;
583 }
585 u_char* ptr = (u_char*)::malloc(alloc_size);
587 if (ptr != NULL) {
588 Atomic::add(((jint) (alloc_size / BytesPerWord)),
589 (volatile jint *) &cur_malloc_words);
590 }
591 return ptr;
592 }
594 void* os::malloc(size_t size, MEMFLAGS memflags, address caller) {
595 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
596 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
598 #ifdef ASSERT
599 // checking for the WatcherThread and crash_protection first
600 // since os::malloc can be called when the libjvm.{dll,so} is
601 // first loaded and we don't have a thread yet.
602 // try to find the thread after we see that the watcher thread
603 // exists and has crash protection.
604 WatcherThread *wt = WatcherThread::watcher_thread();
605 if (wt != NULL && wt->has_crash_protection()) {
606 Thread* thread = ThreadLocalStorage::get_thread_slow();
607 if (thread == wt) {
608 assert(!wt->has_crash_protection(),
609 "Can't malloc with crash protection from WatcherThread");
610 }
611 }
612 #endif
614 if (size == 0) {
615 // return a valid pointer if size is zero
616 // if NULL is returned the calling functions assume out of memory.
617 size = 1;
618 }
620 const size_t alloc_size = size + space_before + space_after;
622 if (size > alloc_size) { // Check for rollover.
623 return NULL;
624 }
626 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
628 u_char* ptr;
630 if (MallocMaxTestWords > 0) {
631 ptr = testMalloc(alloc_size);
632 } else {
633 ptr = (u_char*)::malloc(alloc_size);
634 }
636 #ifdef ASSERT
637 if (ptr == NULL) return NULL;
638 if (MallocCushion) {
639 for (u_char* p = ptr; p < ptr + MallocCushion; p++) *p = (u_char)badResourceValue;
640 u_char* end = ptr + space_before + size;
641 for (u_char* pq = ptr+MallocCushion; pq < end; pq++) *pq = (u_char)uninitBlockPad;
642 for (u_char* q = end; q < end + MallocCushion; q++) *q = (u_char)badResourceValue;
643 }
644 // put size just before data
645 *size_addr_from_base(ptr) = size;
646 #endif
647 u_char* memblock = ptr + space_before;
648 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
649 tty->print_cr("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
650 breakpoint();
651 }
652 debug_only(if (paranoid) verify_block(memblock));
653 if (PrintMalloc && tty != NULL) tty->print_cr("os::malloc " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, memblock);
655 // we do not track MallocCushion memory
656 MemTracker::record_malloc((address)memblock, size, memflags, caller == 0 ? CALLER_PC : caller);
658 return memblock;
659 }
662 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, address caller) {
663 #ifndef ASSERT
664 NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
665 NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
666 MemTracker::Tracker tkr = MemTracker::get_realloc_tracker();
667 void* ptr = ::realloc(memblock, size);
668 if (ptr != NULL) {
669 tkr.record((address)memblock, (address)ptr, size, memflags,
670 caller == 0 ? CALLER_PC : caller);
671 } else {
672 tkr.discard();
673 }
674 return ptr;
675 #else
676 if (memblock == NULL) {
677 return malloc(size, memflags, (caller == 0 ? CALLER_PC : caller));
678 }
679 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
680 tty->print_cr("os::realloc caught " PTR_FORMAT, memblock);
681 breakpoint();
682 }
683 verify_block(memblock);
684 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
685 if (size == 0) return NULL;
686 // always move the block
687 void* ptr = malloc(size, memflags, caller == 0 ? CALLER_PC : caller);
688 if (PrintMalloc) tty->print_cr("os::remalloc " SIZE_FORMAT " bytes, " PTR_FORMAT " --> " PTR_FORMAT, size, memblock, ptr);
689 // Copy to new memory if malloc didn't fail
690 if ( ptr != NULL ) {
691 memcpy(ptr, memblock, MIN2(size, get_size(memblock)));
692 if (paranoid) verify_block(ptr);
693 if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
694 tty->print_cr("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, ptr);
695 breakpoint();
696 }
697 free(memblock);
698 }
699 return ptr;
700 #endif
701 }
704 void os::free(void *memblock, MEMFLAGS memflags) {
705 NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
706 #ifdef ASSERT
707 if (memblock == NULL) return;
708 if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
709 if (tty != NULL) tty->print_cr("os::free caught " PTR_FORMAT, memblock);
710 breakpoint();
711 }
712 verify_block(memblock);
713 NOT_PRODUCT(if (MallocVerifyInterval > 0) check_heap());
714 // Added by detlefs.
715 if (MallocCushion) {
716 u_char* ptr = (u_char*)memblock - space_before;
717 for (u_char* p = ptr; p < ptr + MallocCushion; p++) {
718 guarantee(*p == badResourceValue,
719 "Thing freed should be malloc result.");
720 *p = (u_char)freeBlockPad;
721 }
722 size_t size = get_size(memblock);
723 inc_stat_counter(&free_bytes, size);
724 u_char* end = ptr + space_before + size;
725 for (u_char* q = end; q < end + MallocCushion; q++) {
726 guarantee(*q == badResourceValue,
727 "Thing freed should be malloc result.");
728 *q = (u_char)freeBlockPad;
729 }
730 if (PrintMalloc && tty != NULL)
731 fprintf(stderr, "os::free " SIZE_FORMAT " bytes --> " PTR_FORMAT "\n", size, (uintptr_t)memblock);
732 } else if (PrintMalloc && tty != NULL) {
733 // tty->print_cr("os::free %p", memblock);
734 fprintf(stderr, "os::free " PTR_FORMAT "\n", (uintptr_t)memblock);
735 }
736 #endif
737 MemTracker::record_free((address)memblock, memflags);
739 ::free((char*)memblock - space_before);
740 }
742 void os::init_random(long initval) {
743 _rand_seed = initval;
744 }
747 long os::random() {
748 /* standard, well-known linear congruential random generator with
749 * next_rand = (16807*seed) mod (2**31-1)
750 * see
751 * (1) "Random Number Generators: Good Ones Are Hard to Find",
752 * S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
753 * (2) "Two Fast Implementations of the 'Minimal Standard' Random
754 * Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
755 */
756 const long a = 16807;
757 const unsigned long m = 2147483647;
758 const long q = m / a; assert(q == 127773, "weird math");
759 const long r = m % a; assert(r == 2836, "weird math");
761 // compute az=2^31p+q
762 unsigned long lo = a * (long)(_rand_seed & 0xFFFF);
763 unsigned long hi = a * (long)((unsigned long)_rand_seed >> 16);
764 lo += (hi & 0x7FFF) << 16;
766 // if q overflowed, ignore the overflow and increment q
767 if (lo > m) {
768 lo &= m;
769 ++lo;
770 }
771 lo += hi >> 15;
773 // if (p+q) overflowed, ignore the overflow and increment (p+q)
774 if (lo > m) {
775 lo &= m;
776 ++lo;
777 }
778 return (_rand_seed = lo);
779 }
781 // The INITIALIZED state is distinguished from the SUSPENDED state because the
782 // conditions in which a thread is first started are different from those in which
783 // a suspension is resumed. These differences make it hard for us to apply the
784 // tougher checks when starting threads that we want to do when resuming them.
785 // However, when start_thread is called as a result of Thread.start, on a Java
786 // thread, the operation is synchronized on the Java Thread object. So there
787 // cannot be a race to start the thread and hence for the thread to exit while
788 // we are working on it. Non-Java threads that start Java threads either have
789 // to do so in a context in which races are impossible, or should do appropriate
790 // locking.
792 void os::start_thread(Thread* thread) {
793 // guard suspend/resume
794 MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
795 OSThread* osthread = thread->osthread();
796 osthread->set_state(RUNNABLE);
797 pd_start_thread(thread);
798 }
800 //---------------------------------------------------------------------------
801 // Helper functions for fatal error handler
803 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
804 assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
806 int cols = 0;
807 int cols_per_line = 0;
808 switch (unitsize) {
809 case 1: cols_per_line = 16; break;
810 case 2: cols_per_line = 8; break;
811 case 4: cols_per_line = 4; break;
812 case 8: cols_per_line = 2; break;
813 default: return;
814 }
816 address p = start;
817 st->print(PTR_FORMAT ": ", start);
818 while (p < end) {
819 switch (unitsize) {
820 case 1: st->print("%02x", *(u1*)p); break;
821 case 2: st->print("%04x", *(u2*)p); break;
822 case 4: st->print("%08x", *(u4*)p); break;
823 case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
824 }
825 p += unitsize;
826 cols++;
827 if (cols >= cols_per_line && p < end) {
828 cols = 0;
829 st->cr();
830 st->print(PTR_FORMAT ": ", p);
831 } else {
832 st->print(" ");
833 }
834 }
835 st->cr();
836 }
838 void os::print_environment_variables(outputStream* st, const char** env_list,
839 char* buffer, int len) {
840 if (env_list) {
841 st->print_cr("Environment Variables:");
843 for (int i = 0; env_list[i] != NULL; i++) {
844 if (getenv(env_list[i], buffer, len)) {
845 st->print(env_list[i]);
846 st->print("=");
847 st->print_cr(buffer);
848 }
849 }
850 }
851 }
853 void os::print_cpu_info(outputStream* st) {
854 // cpu
855 st->print("CPU:");
856 st->print("total %d", os::processor_count());
857 // It's not safe to query number of active processors after crash
858 // st->print("(active %d)", os::active_processor_count());
859 st->print(" %s", VM_Version::cpu_features());
860 st->cr();
861 pd_print_cpu_info(st);
862 }
864 void os::print_date_and_time(outputStream *st) {
865 time_t tloc;
866 (void)time(&tloc);
867 st->print("time: %s", ctime(&tloc)); // ctime adds newline.
869 double t = os::elapsedTime();
870 // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
871 // Linux. Must be a bug in glibc ? Workaround is to round "t" to int
872 // before printf. We lost some precision, but who cares?
873 st->print_cr("elapsed time: %d seconds", (int)t);
874 }
876 // moved from debug.cpp (used to be find()) but still called from there
877 // The verbose parameter is only set by the debug code in one case
878 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
879 address addr = (address)x;
880 CodeBlob* b = CodeCache::find_blob_unsafe(addr);
881 if (b != NULL) {
882 if (b->is_buffer_blob()) {
883 // the interpreter is generated into a buffer blob
884 InterpreterCodelet* i = Interpreter::codelet_containing(addr);
885 if (i != NULL) {
886 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", addr, (int)(addr - i->code_begin()));
887 i->print_on(st);
888 return;
889 }
890 if (Interpreter::contains(addr)) {
891 st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
892 " (not bytecode specific)", addr);
893 return;
894 }
895 //
896 if (AdapterHandlerLibrary::contains(b)) {
897 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", addr, (int)(addr - b->code_begin()));
898 AdapterHandlerLibrary::print_handler_on(st, b);
899 }
900 // the stubroutines are generated into a buffer blob
901 StubCodeDesc* d = StubCodeDesc::desc_for(addr);
902 if (d != NULL) {
903 st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", addr, (int)(addr - d->begin()));
904 d->print_on(st);
905 st->cr();
906 return;
907 }
908 if (StubRoutines::contains(addr)) {
909 st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) "
910 "stub routine", addr);
911 return;
912 }
913 // the InlineCacheBuffer is using stubs generated into a buffer blob
914 if (InlineCacheBuffer::contains(addr)) {
915 st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", addr);
916 return;
917 }
918 VtableStub* v = VtableStubs::stub_containing(addr);
919 if (v != NULL) {
920 st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", addr, (int)(addr - v->entry_point()));
921 v->print_on(st);
922 st->cr();
923 return;
924 }
925 }
926 nmethod* nm = b->as_nmethod_or_null();
927 if (nm != NULL) {
928 ResourceMark rm;
929 st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
930 addr, (int)(addr - nm->entry_point()), nm);
931 if (verbose) {
932 st->print(" for ");
933 nm->method()->print_value_on(st);
934 }
935 st->cr();
936 nm->print_nmethod(verbose);
937 return;
938 }
939 st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", addr, (int)(addr - b->code_begin()));
940 b->print_on(st);
941 return;
942 }
944 if (Universe::heap()->is_in(addr)) {
945 HeapWord* p = Universe::heap()->block_start(addr);
946 bool print = false;
947 // If we couldn't find it it just may mean that heap wasn't parseable
948 // See if we were just given an oop directly
949 if (p != NULL && Universe::heap()->block_is_obj(p)) {
950 print = true;
951 } else if (p == NULL && ((oopDesc*)addr)->is_oop()) {
952 p = (HeapWord*) addr;
953 print = true;
954 }
955 if (print) {
956 if (p == (HeapWord*) addr) {
957 st->print_cr(INTPTR_FORMAT " is an oop", addr);
958 } else {
959 st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, addr, p);
960 }
961 oop(p)->print_on(st);
962 return;
963 }
964 } else {
965 if (Universe::heap()->is_in_reserved(addr)) {
966 st->print_cr(INTPTR_FORMAT " is an unallocated location "
967 "in the heap", addr);
968 return;
969 }
970 }
971 if (JNIHandles::is_global_handle((jobject) addr)) {
972 st->print_cr(INTPTR_FORMAT " is a global jni handle", addr);
973 return;
974 }
975 if (JNIHandles::is_weak_global_handle((jobject) addr)) {
976 st->print_cr(INTPTR_FORMAT " is a weak global jni handle", addr);
977 return;
978 }
979 #ifndef PRODUCT
980 // we don't keep the block list in product mode
981 if (JNIHandleBlock::any_contains((jobject) addr)) {
982 st->print_cr(INTPTR_FORMAT " is a local jni handle", addr);
983 return;
984 }
985 #endif
987 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
988 // Check for privilege stack
989 if (thread->privileged_stack_top() != NULL &&
990 thread->privileged_stack_top()->contains(addr)) {
991 st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
992 "for thread: " INTPTR_FORMAT, addr, thread);
993 if (verbose) thread->print_on(st);
994 return;
995 }
996 // If the addr is a java thread print information about that.
997 if (addr == (address)thread) {
998 if (verbose) {
999 thread->print_on(st);
1000 } else {
1001 st->print_cr(INTPTR_FORMAT " is a thread", addr);
1002 }
1003 return;
1004 }
1005 // If the addr is in the stack region for this thread then report that
1006 // and print thread info
1007 if (thread->stack_base() >= addr &&
1008 addr > (thread->stack_base() - thread->stack_size())) {
1009 st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1010 INTPTR_FORMAT, addr, thread);
1011 if (verbose) thread->print_on(st);
1012 return;
1013 }
1015 }
1017 #ifndef PRODUCT
1018 // Check if in metaspace.
1019 if (ClassLoaderDataGraph::contains((address)addr)) {
1020 // Use addr->print() from the debugger instead (not here)
1021 st->print_cr(INTPTR_FORMAT
1022 " is pointing into metadata", addr);
1023 return;
1024 }
1025 #endif
1027 // Try an OS specific find
1028 if (os::find(addr, st)) {
1029 return;
1030 }
1032 st->print_cr(INTPTR_FORMAT " is an unknown value", addr);
1033 }
1035 // Looks like all platforms except IA64 can use the same function to check
1036 // if C stack is walkable beyond current frame. The check for fp() is not
1037 // necessary on Sparc, but it's harmless.
1038 bool os::is_first_C_frame(frame* fr) {
1039 #if defined(IA64) && !defined(_WIN32)
1040 // On IA64 we have to check if the callers bsp is still valid
1041 // (i.e. within the register stack bounds).
1042 // Notice: this only works for threads created by the VM and only if
1043 // we walk the current stack!!! If we want to be able to walk
1044 // arbitrary other threads, we'll have to somehow store the thread
1045 // object in the frame.
1046 Thread *thread = Thread::current();
1047 if ((address)fr->fp() <=
1048 thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1049 // This check is a little hacky, because on Linux the first C
1050 // frame's ('start_thread') register stack frame starts at
1051 // "register_stack_base + 0x48" while on HPUX, the first C frame's
1052 // ('__pthread_bound_body') register stack frame seems to really
1053 // start at "register_stack_base".
1054 return true;
1055 } else {
1056 return false;
1057 }
1058 #elif defined(IA64) && defined(_WIN32)
1059 return true;
1060 #else
1061 // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1062 // Check usp first, because if that's bad the other accessors may fault
1063 // on some architectures. Ditto ufp second, etc.
1064 uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1065 // sp on amd can be 32 bit aligned.
1066 uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1068 uintptr_t usp = (uintptr_t)fr->sp();
1069 if ((usp & sp_align_mask) != 0) return true;
1071 uintptr_t ufp = (uintptr_t)fr->fp();
1072 if ((ufp & fp_align_mask) != 0) return true;
1074 uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1075 if ((old_sp & sp_align_mask) != 0) return true;
1076 if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1078 uintptr_t old_fp = (uintptr_t)fr->link();
1079 if ((old_fp & fp_align_mask) != 0) return true;
1080 if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1082 // stack grows downwards; if old_fp is below current fp or if the stack
1083 // frame is too large, either the stack is corrupted or fp is not saved
1084 // on stack (i.e. on x86, ebp may be used as general register). The stack
1085 // is not walkable beyond current frame.
1086 if (old_fp < ufp) return true;
1087 if (old_fp - ufp > 64 * K) return true;
1089 return false;
1090 #endif
1091 }
1093 #ifdef ASSERT
1094 extern "C" void test_random() {
1095 const double m = 2147483647;
1096 double mean = 0.0, variance = 0.0, t;
1097 long reps = 10000;
1098 unsigned long seed = 1;
1100 tty->print_cr("seed %ld for %ld repeats...", seed, reps);
1101 os::init_random(seed);
1102 long num;
1103 for (int k = 0; k < reps; k++) {
1104 num = os::random();
1105 double u = (double)num / m;
1106 assert(u >= 0.0 && u <= 1.0, "bad random number!");
1108 // calculate mean and variance of the random sequence
1109 mean += u;
1110 variance += (u*u);
1111 }
1112 mean /= reps;
1113 variance /= (reps - 1);
1115 assert(num == 1043618065, "bad seed");
1116 tty->print_cr("mean of the 1st 10000 numbers: %f", mean);
1117 tty->print_cr("variance of the 1st 10000 numbers: %f", variance);
1118 const double eps = 0.0001;
1119 t = fabsd(mean - 0.5018);
1120 assert(t < eps, "bad mean");
1121 t = (variance - 0.3355) < 0.0 ? -(variance - 0.3355) : variance - 0.3355;
1122 assert(t < eps, "bad variance");
1123 }
1124 #endif
1127 // Set up the boot classpath.
1129 char* os::format_boot_path(const char* format_string,
1130 const char* home,
1131 int home_len,
1132 char fileSep,
1133 char pathSep) {
1134 assert((fileSep == '/' && pathSep == ':') ||
1135 (fileSep == '\\' && pathSep == ';'), "unexpected seperator chars");
1137 // Scan the format string to determine the length of the actual
1138 // boot classpath, and handle platform dependencies as well.
1139 int formatted_path_len = 0;
1140 const char* p;
1141 for (p = format_string; *p != 0; ++p) {
1142 if (*p == '%') formatted_path_len += home_len - 1;
1143 ++formatted_path_len;
1144 }
1146 char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1147 if (formatted_path == NULL) {
1148 return NULL;
1149 }
1151 // Create boot classpath from format, substituting separator chars and
1152 // java home directory.
1153 char* q = formatted_path;
1154 for (p = format_string; *p != 0; ++p) {
1155 switch (*p) {
1156 case '%':
1157 strcpy(q, home);
1158 q += home_len;
1159 break;
1160 case '/':
1161 *q++ = fileSep;
1162 break;
1163 case ':':
1164 *q++ = pathSep;
1165 break;
1166 default:
1167 *q++ = *p;
1168 }
1169 }
1170 *q = '\0';
1172 assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1173 return formatted_path;
1174 }
1177 bool os::set_boot_path(char fileSep, char pathSep) {
1178 const char* home = Arguments::get_java_home();
1179 int home_len = (int)strlen(home);
1181 static const char* meta_index_dir_format = "%/lib/";
1182 static const char* meta_index_format = "%/lib/meta-index";
1183 char* meta_index = format_boot_path(meta_index_format, home, home_len, fileSep, pathSep);
1184 if (meta_index == NULL) return false;
1185 char* meta_index_dir = format_boot_path(meta_index_dir_format, home, home_len, fileSep, pathSep);
1186 if (meta_index_dir == NULL) return false;
1187 Arguments::set_meta_index_path(meta_index, meta_index_dir);
1189 // Any modification to the JAR-file list, for the boot classpath must be
1190 // aligned with install/install/make/common/Pack.gmk. Note: boot class
1191 // path class JARs, are stripped for StackMapTable to reduce download size.
1192 static const char classpath_format[] =
1193 "%/lib/resources.jar:"
1194 "%/lib/rt.jar:"
1195 "%/lib/sunrsasign.jar:"
1196 "%/lib/jsse.jar:"
1197 "%/lib/jce.jar:"
1198 "%/lib/charsets.jar:"
1199 "%/lib/jfr.jar:"
1200 #ifdef __APPLE__
1201 "%/lib/JObjC.jar:"
1202 #endif
1203 "%/classes";
1204 char* sysclasspath = format_boot_path(classpath_format, home, home_len, fileSep, pathSep);
1205 if (sysclasspath == NULL) return false;
1206 Arguments::set_sysclasspath(sysclasspath);
1208 return true;
1209 }
1211 /*
1212 * Splits a path, based on its separator, the number of
1213 * elements is returned back in n.
1214 * It is the callers responsibility to:
1215 * a> check the value of n, and n may be 0.
1216 * b> ignore any empty path elements
1217 * c> free up the data.
1218 */
1219 char** os::split_path(const char* path, int* n) {
1220 *n = 0;
1221 if (path == NULL || strlen(path) == 0) {
1222 return NULL;
1223 }
1224 const char psepchar = *os::path_separator();
1225 char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1226 if (inpath == NULL) {
1227 return NULL;
1228 }
1229 strcpy(inpath, path);
1230 int count = 1;
1231 char* p = strchr(inpath, psepchar);
1232 // Get a count of elements to allocate memory
1233 while (p != NULL) {
1234 count++;
1235 p++;
1236 p = strchr(p, psepchar);
1237 }
1238 char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1239 if (opath == NULL) {
1240 return NULL;
1241 }
1243 // do the actual splitting
1244 p = inpath;
1245 for (int i = 0 ; i < count ; i++) {
1246 size_t len = strcspn(p, os::path_separator());
1247 if (len > JVM_MAXPATHLEN) {
1248 return NULL;
1249 }
1250 // allocate the string and add terminator storage
1251 char* s = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1252 if (s == NULL) {
1253 return NULL;
1254 }
1255 strncpy(s, p, len);
1256 s[len] = '\0';
1257 opath[i] = s;
1258 p += len + 1;
1259 }
1260 FREE_C_HEAP_ARRAY(char, inpath, mtInternal);
1261 *n = count;
1262 return opath;
1263 }
1265 void os::set_memory_serialize_page(address page) {
1266 int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1267 _mem_serialize_page = (volatile int32_t *)page;
1268 // We initialize the serialization page shift count here
1269 // We assume a cache line size of 64 bytes
1270 assert(SerializePageShiftCount == count,
1271 "thread size changed, fix SerializePageShiftCount constant");
1272 set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1273 }
1275 static volatile intptr_t SerializePageLock = 0;
1277 // This method is called from signal handler when SIGSEGV occurs while the current
1278 // thread tries to store to the "read-only" memory serialize page during state
1279 // transition.
1280 void os::block_on_serialize_page_trap() {
1281 if (TraceSafepoint) {
1282 tty->print_cr("Block until the serialize page permission restored");
1283 }
1284 // When VMThread is holding the SerializePageLock during modifying the
1285 // access permission of the memory serialize page, the following call
1286 // will block until the permission of that page is restored to rw.
1287 // Generally, it is unsafe to manipulate locks in signal handlers, but in
1288 // this case, it's OK as the signal is synchronous and we know precisely when
1289 // it can occur.
1290 Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1291 Thread::muxRelease(&SerializePageLock);
1292 }
1294 // Serialize all thread state variables
1295 void os::serialize_thread_states() {
1296 // On some platforms such as Solaris & Linux, the time duration of the page
1297 // permission restoration is observed to be much longer than expected due to
1298 // scheduler starvation problem etc. To avoid the long synchronization
1299 // time and expensive page trap spinning, 'SerializePageLock' is used to block
1300 // the mutator thread if such case is encountered. See bug 6546278 for details.
1301 Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1302 os::protect_memory((char *)os::get_memory_serialize_page(),
1303 os::vm_page_size(), MEM_PROT_READ);
1304 os::protect_memory((char *)os::get_memory_serialize_page(),
1305 os::vm_page_size(), MEM_PROT_RW);
1306 Thread::muxRelease(&SerializePageLock);
1307 }
1309 // Returns true if the current stack pointer is above the stack shadow
1310 // pages, false otherwise.
1312 bool os::stack_shadow_pages_available(Thread *thread, methodHandle method) {
1313 assert(StackRedPages > 0 && StackYellowPages > 0,"Sanity check");
1314 address sp = current_stack_pointer();
1315 // Check if we have StackShadowPages above the yellow zone. This parameter
1316 // is dependent on the depth of the maximum VM call stack possible from
1317 // the handler for stack overflow. 'instanceof' in the stack overflow
1318 // handler or a println uses at least 8k stack of VM and native code
1319 // respectively.
1320 const int framesize_in_bytes =
1321 Interpreter::size_top_interpreter_activation(method()) * wordSize;
1322 int reserved_area = ((StackShadowPages + StackRedPages + StackYellowPages)
1323 * vm_page_size()) + framesize_in_bytes;
1324 // The very lower end of the stack
1325 address stack_limit = thread->stack_base() - thread->stack_size();
1326 return (sp > (stack_limit + reserved_area));
1327 }
1329 size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
1330 uint min_pages)
1331 {
1332 assert(min_pages > 0, "sanity");
1333 if (UseLargePages) {
1334 const size_t max_page_size = region_max_size / min_pages;
1336 for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1337 const size_t sz = _page_sizes[i];
1338 const size_t mask = sz - 1;
1339 if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1340 // The largest page size with no fragmentation.
1341 return sz;
1342 }
1344 if (sz <= max_page_size) {
1345 // The largest page size that satisfies the min_pages requirement.
1346 return sz;
1347 }
1348 }
1349 }
1351 return vm_page_size();
1352 }
1354 #ifndef PRODUCT
1355 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
1356 {
1357 if (TracePageSizes) {
1358 tty->print("%s: ", str);
1359 for (int i = 0; i < count; ++i) {
1360 tty->print(" " SIZE_FORMAT, page_sizes[i]);
1361 }
1362 tty->cr();
1363 }
1364 }
1366 void os::trace_page_sizes(const char* str, const size_t region_min_size,
1367 const size_t region_max_size, const size_t page_size,
1368 const char* base, const size_t size)
1369 {
1370 if (TracePageSizes) {
1371 tty->print_cr("%s: min=" SIZE_FORMAT " max=" SIZE_FORMAT
1372 " pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT
1373 " size=" SIZE_FORMAT,
1374 str, region_min_size, region_max_size,
1375 page_size, base, size);
1376 }
1377 }
1378 #endif // #ifndef PRODUCT
1380 // This is the working definition of a server class machine:
1381 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1382 // because the graphics memory (?) sometimes masks physical memory.
1383 // If you want to change the definition of a server class machine
1384 // on some OS or platform, e.g., >=4GB on Windohs platforms,
1385 // then you'll have to parameterize this method based on that state,
1386 // as was done for logical processors here, or replicate and
1387 // specialize this method for each platform. (Or fix os to have
1388 // some inheritance structure and use subclassing. Sigh.)
1389 // If you want some platform to always or never behave as a server
1390 // class machine, change the setting of AlwaysActAsServerClassMachine
1391 // and NeverActAsServerClassMachine in globals*.hpp.
1392 bool os::is_server_class_machine() {
1393 // First check for the early returns
1394 if (NeverActAsServerClassMachine) {
1395 return false;
1396 }
1397 if (AlwaysActAsServerClassMachine) {
1398 return true;
1399 }
1400 // Then actually look at the machine
1401 bool result = false;
1402 const unsigned int server_processors = 2;
1403 const julong server_memory = 2UL * G;
1404 // We seem not to get our full complement of memory.
1405 // We allow some part (1/8?) of the memory to be "missing",
1406 // based on the sizes of DIMMs, and maybe graphics cards.
1407 const julong missing_memory = 256UL * M;
1409 /* Is this a server class machine? */
1410 if ((os::active_processor_count() >= (int)server_processors) &&
1411 (os::physical_memory() >= (server_memory - missing_memory))) {
1412 const unsigned int logical_processors =
1413 VM_Version::logical_processors_per_package();
1414 if (logical_processors > 1) {
1415 const unsigned int physical_packages =
1416 os::active_processor_count() / logical_processors;
1417 if (physical_packages > server_processors) {
1418 result = true;
1419 }
1420 } else {
1421 result = true;
1422 }
1423 }
1424 return result;
1425 }
1427 // Read file line by line, if line is longer than bsize,
1428 // skip rest of line.
1429 int os::get_line_chars(int fd, char* buf, const size_t bsize){
1430 size_t sz, i = 0;
1432 // read until EOF, EOL or buf is full
1433 while ((sz = (int) read(fd, &buf[i], 1)) == 1 && i < (bsize-2) && buf[i] != '\n') {
1434 ++i;
1435 }
1437 if (buf[i] == '\n') {
1438 // EOL reached so ignore EOL character and return
1440 buf[i] = 0;
1441 return (int) i;
1442 }
1444 buf[i+1] = 0;
1446 if (sz != 1) {
1447 // EOF reached. if we read chars before EOF return them and
1448 // return EOF on next call otherwise return EOF
1450 return (i == 0) ? -1 : (int) i;
1451 }
1453 // line is longer than size of buf, skip to EOL
1454 char ch;
1455 while (read(fd, &ch, 1) == 1 && ch != '\n') {
1456 // Do nothing
1457 }
1459 // return initial part of line that fits in buf.
1460 // If we reached EOF, it will be returned on next call.
1462 return (int) i;
1463 }
1465 void os::SuspendedThreadTask::run() {
1466 assert(Threads_lock->owned_by_self() || (_thread == VMThread::vm_thread()), "must have threads lock to call this");
1467 internal_do_task();
1468 _done = true;
1469 }
1471 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1472 return os::pd_create_stack_guard_pages(addr, bytes);
1473 }
1475 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint) {
1476 char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1477 if (result != NULL) {
1478 MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1479 }
1481 return result;
1482 }
1484 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1485 MEMFLAGS flags) {
1486 char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1487 if (result != NULL) {
1488 MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1489 MemTracker::record_virtual_memory_type((address)result, flags);
1490 }
1492 return result;
1493 }
1495 char* os::attempt_reserve_memory_at(size_t bytes, char* addr) {
1496 char* result = pd_attempt_reserve_memory_at(bytes, addr);
1497 if (result != NULL) {
1498 MemTracker::record_virtual_memory_reserve((address)result, bytes, mtNone, CALLER_PC);
1499 }
1500 return result;
1501 }
1503 void os::split_reserved_memory(char *base, size_t size,
1504 size_t split, bool realloc) {
1505 pd_split_reserved_memory(base, size, split, realloc);
1506 }
1508 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1509 bool res = pd_commit_memory(addr, bytes, executable);
1510 if (res) {
1511 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1512 }
1513 return res;
1514 }
1516 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1517 bool executable) {
1518 bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1519 if (res) {
1520 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1521 }
1522 return res;
1523 }
1525 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1526 const char* mesg) {
1527 pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1528 MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1529 }
1531 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1532 bool executable, const char* mesg) {
1533 os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1534 MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1535 }
1537 bool os::uncommit_memory(char* addr, size_t bytes) {
1538 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_uncommit_tracker();
1539 bool res = pd_uncommit_memory(addr, bytes);
1540 if (res) {
1541 tkr.record((address)addr, bytes);
1542 } else {
1543 tkr.discard();
1544 }
1545 return res;
1546 }
1548 bool os::release_memory(char* addr, size_t bytes) {
1549 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1550 bool res = pd_release_memory(addr, bytes);
1551 if (res) {
1552 tkr.record((address)addr, bytes);
1553 } else {
1554 tkr.discard();
1555 }
1556 return res;
1557 }
1560 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1561 char *addr, size_t bytes, bool read_only,
1562 bool allow_exec) {
1563 char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1564 if (result != NULL) {
1565 MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, mtNone, CALLER_PC);
1566 }
1567 return result;
1568 }
1570 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1571 char *addr, size_t bytes, bool read_only,
1572 bool allow_exec) {
1573 return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1574 read_only, allow_exec);
1575 }
1577 bool os::unmap_memory(char *addr, size_t bytes) {
1578 MemTracker::Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
1579 bool result = pd_unmap_memory(addr, bytes);
1580 if (result) {
1581 tkr.record((address)addr, bytes);
1582 } else {
1583 tkr.discard();
1584 }
1585 return result;
1586 }
1588 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1589 pd_free_memory(addr, bytes, alignment_hint);
1590 }
1592 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1593 pd_realign_memory(addr, bytes, alignment_hint);
1594 }
1596 #ifndef TARGET_OS_FAMILY_windows
1597 /* try to switch state from state "from" to state "to"
1598 * returns the state set after the method is complete
1599 */
1600 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1601 os::SuspendResume::State to)
1602 {
1603 os::SuspendResume::State result =
1604 (os::SuspendResume::State) Atomic::cmpxchg((jint) to, (jint *) &_state, (jint) from);
1605 if (result == from) {
1606 // success
1607 return to;
1608 }
1609 return result;
1610 }
1611 #endif