1 /*
2 * Copyright (c) 1999, 2017, 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 */
24
25 #include "utilities/globalDefinitions.hpp"
26 #include "prims/jvm.h"
27 #include "semaphore_posix.hpp"
28 #include "runtime/frame.inline.hpp"
29 #include "runtime/interfaceSupport.hpp"
30 #include "runtime/os.hpp"
31 #include "utilities/macros.hpp"
32 #include "utilities/vmError.hpp"
33
34 #include <dlfcn.h>
35 #include <pthread.h>
36 #include <semaphore.h>
37 #include <signal.h>
38 #include <sys/resource.h>
39 #include <sys/utsname.h>
40 #include <time.h>
41 #include <unistd.h>
42
43 // Todo: provide a os::get_max_process_id() or similar. Number of processes
44 // may have been configured, can be read more accurately from proc fs etc.
45 #ifndef MAX_PID
46 #define MAX_PID INT_MAX
47 #endif
48 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
49
50 // Check core dump limit and report possible place where core can be found
51 void os::check_dump_limit(char* buffer, size_t bufferSize) {
52 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) {
53 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line");
54 VMError::record_coredump_status(buffer, false);
55 return;
56 }
57
58 int n;
59 struct rlimit rlim;
60 bool success;
61
62 char core_path[PATH_MAX];
63 n = get_core_path(core_path, PATH_MAX);
64
65 if (n <= 0) {
66 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());
67 success = true;
68 #ifdef LINUX
69 } else if (core_path[0] == '"') { // redirect to user process
70 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);
71 success = true;
72 #endif
73 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
74 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);
75 success = true;
76 } else {
77 switch(rlim.rlim_cur) {
78 case RLIM_INFINITY:
79 jio_snprintf(buffer, bufferSize, "%s", core_path);
80 success = true;
81 break;
82 case 0:
83 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
84 success = false;
85 break;
86 default:
87 jio_snprintf(buffer, bufferSize, "%s (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, (unsigned long)(rlim.rlim_cur >> 10));
88 success = true;
89 break;
90 }
91 }
92
93 VMError::record_coredump_status(buffer, success);
94 }
95
96 int os::get_native_stack(address* stack, int frames, int toSkip) {
97 int frame_idx = 0;
98 int num_of_frames; // number of frames captured
99 frame fr = os::current_frame();
100 while (fr.pc() && frame_idx < frames) {
101 if (toSkip > 0) {
102 toSkip --;
103 } else {
104 stack[frame_idx ++] = fr.pc();
105 }
106 if (fr.fp() == NULL || fr.cb() != NULL ||
107 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;
108
109 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
110 fr = os::get_sender_for_C_frame(&fr);
111 } else {
112 break;
113 }
114 }
115 num_of_frames = frame_idx;
116 for (; frame_idx < frames; frame_idx ++) {
117 stack[frame_idx] = NULL;
118 }
119
120 return num_of_frames;
121 }
122
123
124 bool os::unsetenv(const char* name) {
125 assert(name != NULL, "Null pointer");
126 return (::unsetenv(name) == 0);
127 }
128
129 int os::get_last_error() {
130 return errno;
131 }
132
133 bool os::is_debugger_attached() {
134 // not implemented
135 return false;
136 }
137
138 void os::wait_for_keypress_at_exit(void) {
139 // don't do anything on posix platforms
140 return;
141 }
142
143 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
144 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
145 // rather than unmapping and remapping the whole chunk to get requested alignment.
146 char* os::reserve_memory_aligned(size_t size, size_t alignment) {
147 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
148 "Alignment must be a multiple of allocation granularity (page size)");
149 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
150
151 size_t extra_size = size + alignment;
152 assert(extra_size >= size, "overflow, size is too large to allow alignment");
153
154 char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
155
156 if (extra_base == NULL) {
157 return NULL;
158 }
159
160 // Do manual alignment
161 char* aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment);
162
163 // [ | | ]
164 // ^ extra_base
165 // ^ extra_base + begin_offset == aligned_base
166 // extra_base + begin_offset + size ^
167 // extra_base + extra_size ^
168 // |<>| == begin_offset
169 // end_offset == |<>|
170 size_t begin_offset = aligned_base - extra_base;
171 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
172
173 if (begin_offset > 0) {
174 os::release_memory(extra_base, begin_offset);
175 }
176
177 if (end_offset > 0) {
178 os::release_memory(extra_base + begin_offset + size, end_offset);
179 }
180
181 return aligned_base;
182 }
183
184 int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
185 return vsnprintf(buf, len, fmt, args);
186 }
187
188 int os::get_fileno(FILE* fp) {
189 return NOT_AIX(::)fileno(fp);
190 }
191
192 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
193 return gmtime_r(clock, res);
194 }
195
196 void os::Posix::print_load_average(outputStream* st) {
197 st->print("load average:");
198 double loadavg[3];
199 os::loadavg(loadavg, 3);
200 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
201 st->cr();
202 }
203
204 void os::Posix::print_rlimit_info(outputStream* st) {
205 st->print("rlimit:");
206 struct rlimit rlim;
207
208 st->print(" STACK ");
209 getrlimit(RLIMIT_STACK, &rlim);
210 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
211 else st->print("%luk", rlim.rlim_cur >> 10);
212
213 st->print(", CORE ");
214 getrlimit(RLIMIT_CORE, &rlim);
215 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
216 else st->print("%luk", rlim.rlim_cur >> 10);
217
218 // Isn't there on solaris
219 #if !defined(SOLARIS) && !defined(AIX)
220 st->print(", NPROC ");
221 getrlimit(RLIMIT_NPROC, &rlim);
222 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
223 else st->print("%lu", rlim.rlim_cur);
224 #endif
225
226 st->print(", NOFILE ");
227 getrlimit(RLIMIT_NOFILE, &rlim);
228 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
229 else st->print("%lu", rlim.rlim_cur);
230
231 st->print(", AS ");
232 getrlimit(RLIMIT_AS, &rlim);
233 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
234 else st->print("%luk", rlim.rlim_cur >> 10);
235 st->cr();
236 }
237
238 void os::Posix::print_uname_info(outputStream* st) {
239 // kernel
240 st->print("uname:");
241 struct utsname name;
242 uname(&name);
243 st->print("%s ", name.sysname);
244 #ifdef ASSERT
245 st->print("%s ", name.nodename);
246 #endif
247 st->print("%s ", name.release);
248 st->print("%s ", name.version);
249 st->print("%s", name.machine);
250 st->cr();
251 }
252
253 bool os::get_host_name(char* buf, size_t buflen) {
254 struct utsname name;
255 uname(&name);
256 jio_snprintf(buf, buflen, "%s", name.nodename);
257 return true;
258 }
259
260 bool os::has_allocatable_memory_limit(julong* limit) {
261 struct rlimit rlim;
262 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
263 // if there was an error when calling getrlimit, assume that there is no limitation
264 // on virtual memory.
265 bool result;
266 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
267 result = false;
268 } else {
269 *limit = (julong)rlim.rlim_cur;
270 result = true;
271 }
272 #ifdef _LP64
273 return result;
274 #else
275 // arbitrary virtual space limit for 32 bit Unices found by testing. If
276 // getrlimit above returned a limit, bound it with this limit. Otherwise
277 // directly use it.
278 const julong max_virtual_limit = (julong)3800*M;
279 if (result) {
280 *limit = MIN2(*limit, max_virtual_limit);
281 } else {
282 *limit = max_virtual_limit;
283 }
284
285 // bound by actually allocatable memory. The algorithm uses two bounds, an
286 // upper and a lower limit. The upper limit is the current highest amount of
287 // memory that could not be allocated, the lower limit is the current highest
288 // amount of memory that could be allocated.
289 // The algorithm iteratively refines the result by halving the difference
290 // between these limits, updating either the upper limit (if that value could
291 // not be allocated) or the lower limit (if the that value could be allocated)
292 // until the difference between these limits is "small".
293
294 // the minimum amount of memory we care about allocating.
295 const julong min_allocation_size = M;
296
297 julong upper_limit = *limit;
298
299 // first check a few trivial cases
300 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
301 *limit = upper_limit;
302 } else if (!is_allocatable(min_allocation_size)) {
303 // we found that not even min_allocation_size is allocatable. Return it
304 // anyway. There is no point to search for a better value any more.
305 *limit = min_allocation_size;
306 } else {
307 // perform the binary search.
308 julong lower_limit = min_allocation_size;
309 while ((upper_limit - lower_limit) > min_allocation_size) {
310 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
311 temp_limit = align_size_down_(temp_limit, min_allocation_size);
312 if (is_allocatable(temp_limit)) {
313 lower_limit = temp_limit;
314 } else {
315 upper_limit = temp_limit;
316 }
317 }
318 *limit = lower_limit;
319 }
320 return true;
321 #endif
322 }
323
324 const char* os::get_current_directory(char *buf, size_t buflen) {
325 return getcwd(buf, buflen);
326 }
327
328 FILE* os::open(int fd, const char* mode) {
329 return ::fdopen(fd, mode);
330 }
331
332 void os::flockfile(FILE* fp) {
333 ::flockfile(fp);
334 }
335
336 void os::funlockfile(FILE* fp) {
337 ::funlockfile(fp);
338 }
339
340 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
341 // which is used to find statically linked in agents.
342 // Parameters:
343 // sym_name: Symbol in library we are looking for
344 // lib_name: Name of library to look in, NULL for shared libs.
345 // is_absolute_path == true if lib_name is absolute path to agent
346 // such as "/a/b/libL.so"
347 // == false if only the base name of the library is passed in
348 // such as "L"
349 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
350 bool is_absolute_path) {
351 char *agent_entry_name;
352 size_t len;
353 size_t name_len;
354 size_t prefix_len = strlen(JNI_LIB_PREFIX);
355 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
356 const char *start;
357
358 if (lib_name != NULL) {
359 name_len = strlen(lib_name);
360 if (is_absolute_path) {
361 // Need to strip path, prefix and suffix
362 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
363 lib_name = ++start;
364 }
365 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
366 return NULL;
367 }
368 lib_name += prefix_len;
369 name_len = strlen(lib_name) - suffix_len;
370 }
371 }
372 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
373 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
374 if (agent_entry_name == NULL) {
375 return NULL;
376 }
377 strcpy(agent_entry_name, sym_name);
378 if (lib_name != NULL) {
379 strcat(agent_entry_name, "_");
380 strncat(agent_entry_name, lib_name, name_len);
381 }
382 return agent_entry_name;
383 }
384
385 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
386 assert(thread == Thread::current(), "thread consistency check");
387
388 ParkEvent * const slp = thread->_SleepEvent ;
389 slp->reset() ;
390 OrderAccess::fence() ;
391
392 if (interruptible) {
393 jlong prevtime = javaTimeNanos();
394
395 for (;;) {
396 if (os::is_interrupted(thread, true)) {
397 return OS_INTRPT;
398 }
399
400 jlong newtime = javaTimeNanos();
401
402 if (newtime - prevtime < 0) {
403 // time moving backwards, should only happen if no monotonic clock
404 // not a guarantee() because JVM should not abort on kernel/glibc bugs
405 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
406 } else {
407 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
408 }
409
410 if (millis <= 0) {
411 return OS_OK;
412 }
413
414 prevtime = newtime;
415
416 {
417 assert(thread->is_Java_thread(), "sanity check");
418 JavaThread *jt = (JavaThread *) thread;
419 ThreadBlockInVM tbivm(jt);
420 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
421
422 jt->set_suspend_equivalent();
423 // cleared by handle_special_suspend_equivalent_condition() or
424 // java_suspend_self() via check_and_wait_while_suspended()
425
426 slp->park(millis);
427
428 // were we externally suspended while we were waiting?
429 jt->check_and_wait_while_suspended();
430 }
431 }
432 } else {
433 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
434 jlong prevtime = javaTimeNanos();
435
436 for (;;) {
437 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
438 // the 1st iteration ...
439 jlong newtime = javaTimeNanos();
440
441 if (newtime - prevtime < 0) {
442 // time moving backwards, should only happen if no monotonic clock
443 // not a guarantee() because JVM should not abort on kernel/glibc bugs
444 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
445 } else {
446 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
447 }
448
449 if (millis <= 0) break ;
450
451 prevtime = newtime;
452 slp->park(millis);
453 }
454 return OS_OK ;
455 }
456 }
457
458 ////////////////////////////////////////////////////////////////////////////////
459 // interrupt support
460
461 void os::interrupt(Thread* thread) {
462 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
463 "possibility of dangling Thread pointer");
464
465 OSThread* osthread = thread->osthread();
466
467 if (!osthread->interrupted()) {
468 osthread->set_interrupted(true);
469 // More than one thread can get here with the same value of osthread,
470 // resulting in multiple notifications. We do, however, want the store
471 // to interrupted() to be visible to other threads before we execute unpark().
472 OrderAccess::fence();
473 ParkEvent * const slp = thread->_SleepEvent ;
474 if (slp != NULL) slp->unpark() ;
475 }
476
477 // For JSR166. Unpark even if interrupt status already was set
478 if (thread->is_Java_thread())
479 ((JavaThread*)thread)->parker()->unpark();
480
481 ParkEvent * ev = thread->_ParkEvent ;
482 if (ev != NULL) ev->unpark() ;
483
484 }
485
486 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
487 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
488 "possibility of dangling Thread pointer");
489
490 OSThread* osthread = thread->osthread();
491
492 bool interrupted = osthread->interrupted();
493
494 // NOTE that since there is no "lock" around the interrupt and
495 // is_interrupted operations, there is the possibility that the
496 // interrupted flag (in osThread) will be "false" but that the
497 // low-level events will be in the signaled state. This is
498 // intentional. The effect of this is that Object.wait() and
499 // LockSupport.park() will appear to have a spurious wakeup, which
500 // is allowed and not harmful, and the possibility is so rare that
501 // it is not worth the added complexity to add yet another lock.
502 // For the sleep event an explicit reset is performed on entry
503 // to os::sleep, so there is no early return. It has also been
504 // recommended not to put the interrupted flag into the "event"
505 // structure because it hides the issue.
506 if (interrupted && clear_interrupted) {
507 osthread->set_interrupted(false);
508 // consider thread->_SleepEvent->reset() ... optional optimization
509 }
510
511 return interrupted;
512 }
513
514
515
516 static const struct {
517 int sig; const char* name;
518 }
519 g_signal_info[] =
520 {
521 { SIGABRT, "SIGABRT" },
522 #ifdef SIGAIO
523 { SIGAIO, "SIGAIO" },
524 #endif
525 { SIGALRM, "SIGALRM" },
526 #ifdef SIGALRM1
527 { SIGALRM1, "SIGALRM1" },
528 #endif
529 { SIGBUS, "SIGBUS" },
530 #ifdef SIGCANCEL
531 { SIGCANCEL, "SIGCANCEL" },
532 #endif
533 { SIGCHLD, "SIGCHLD" },
534 #ifdef SIGCLD
535 { SIGCLD, "SIGCLD" },
536 #endif
537 { SIGCONT, "SIGCONT" },
538 #ifdef SIGCPUFAIL
539 { SIGCPUFAIL, "SIGCPUFAIL" },
540 #endif
541 #ifdef SIGDANGER
542 { SIGDANGER, "SIGDANGER" },
543 #endif
544 #ifdef SIGDIL
545 { SIGDIL, "SIGDIL" },
546 #endif
547 #ifdef SIGEMT
548 { SIGEMT, "SIGEMT" },
549 #endif
550 { SIGFPE, "SIGFPE" },
551 #ifdef SIGFREEZE
552 { SIGFREEZE, "SIGFREEZE" },
553 #endif
554 #ifdef SIGGFAULT
555 { SIGGFAULT, "SIGGFAULT" },
556 #endif
557 #ifdef SIGGRANT
558 { SIGGRANT, "SIGGRANT" },
559 #endif
560 { SIGHUP, "SIGHUP" },
561 { SIGILL, "SIGILL" },
562 { SIGINT, "SIGINT" },
563 #ifdef SIGIO
564 { SIGIO, "SIGIO" },
565 #endif
566 #ifdef SIGIOINT
567 { SIGIOINT, "SIGIOINT" },
568 #endif
569 #ifdef SIGIOT
570 // SIGIOT is there for BSD compatibility, but on most Unices just a
571 // synonym for SIGABRT. The result should be "SIGABRT", not
572 // "SIGIOT".
573 #if (SIGIOT != SIGABRT )
574 { SIGIOT, "SIGIOT" },
575 #endif
576 #endif
577 #ifdef SIGKAP
578 { SIGKAP, "SIGKAP" },
579 #endif
580 { SIGKILL, "SIGKILL" },
581 #ifdef SIGLOST
582 { SIGLOST, "SIGLOST" },
583 #endif
584 #ifdef SIGLWP
585 { SIGLWP, "SIGLWP" },
586 #endif
587 #ifdef SIGLWPTIMER
588 { SIGLWPTIMER, "SIGLWPTIMER" },
589 #endif
590 #ifdef SIGMIGRATE
591 { SIGMIGRATE, "SIGMIGRATE" },
592 #endif
593 #ifdef SIGMSG
594 { SIGMSG, "SIGMSG" },
595 #endif
596 { SIGPIPE, "SIGPIPE" },
597 #ifdef SIGPOLL
598 { SIGPOLL, "SIGPOLL" },
599 #endif
600 #ifdef SIGPRE
601 { SIGPRE, "SIGPRE" },
602 #endif
603 { SIGPROF, "SIGPROF" },
604 #ifdef SIGPTY
605 { SIGPTY, "SIGPTY" },
606 #endif
607 #ifdef SIGPWR
608 { SIGPWR, "SIGPWR" },
609 #endif
610 { SIGQUIT, "SIGQUIT" },
611 #ifdef SIGRECONFIG
612 { SIGRECONFIG, "SIGRECONFIG" },
613 #endif
614 #ifdef SIGRECOVERY
615 { SIGRECOVERY, "SIGRECOVERY" },
616 #endif
617 #ifdef SIGRESERVE
618 { SIGRESERVE, "SIGRESERVE" },
619 #endif
620 #ifdef SIGRETRACT
621 { SIGRETRACT, "SIGRETRACT" },
622 #endif
623 #ifdef SIGSAK
624 { SIGSAK, "SIGSAK" },
625 #endif
626 { SIGSEGV, "SIGSEGV" },
627 #ifdef SIGSOUND
628 { SIGSOUND, "SIGSOUND" },
629 #endif
630 #ifdef SIGSTKFLT
631 { SIGSTKFLT, "SIGSTKFLT" },
632 #endif
633 { SIGSTOP, "SIGSTOP" },
634 { SIGSYS, "SIGSYS" },
635 #ifdef SIGSYSERROR
636 { SIGSYSERROR, "SIGSYSERROR" },
637 #endif
638 #ifdef SIGTALRM
639 { SIGTALRM, "SIGTALRM" },
640 #endif
641 { SIGTERM, "SIGTERM" },
642 #ifdef SIGTHAW
643 { SIGTHAW, "SIGTHAW" },
644 #endif
645 { SIGTRAP, "SIGTRAP" },
646 #ifdef SIGTSTP
647 { SIGTSTP, "SIGTSTP" },
648 #endif
649 { SIGTTIN, "SIGTTIN" },
650 { SIGTTOU, "SIGTTOU" },
651 #ifdef SIGURG
652 { SIGURG, "SIGURG" },
653 #endif
654 { SIGUSR1, "SIGUSR1" },
655 { SIGUSR2, "SIGUSR2" },
656 #ifdef SIGVIRT
657 { SIGVIRT, "SIGVIRT" },
658 #endif
659 { SIGVTALRM, "SIGVTALRM" },
660 #ifdef SIGWAITING
661 { SIGWAITING, "SIGWAITING" },
662 #endif
663 #ifdef SIGWINCH
664 { SIGWINCH, "SIGWINCH" },
665 #endif
666 #ifdef SIGWINDOW
667 { SIGWINDOW, "SIGWINDOW" },
668 #endif
669 { SIGXCPU, "SIGXCPU" },
670 { SIGXFSZ, "SIGXFSZ" },
671 #ifdef SIGXRES
672 { SIGXRES, "SIGXRES" },
673 #endif
674 { -1, NULL }
675 };
676
677 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
678 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
679
680 const char* ret = NULL;
681
682 #ifdef SIGRTMIN
683 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
684 if (sig == SIGRTMIN) {
685 ret = "SIGRTMIN";
686 } else if (sig == SIGRTMAX) {
687 ret = "SIGRTMAX";
688 } else {
689 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
690 return out;
691 }
692 }
693 #endif
694
695 if (sig > 0) {
696 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
697 if (g_signal_info[idx].sig == sig) {
698 ret = g_signal_info[idx].name;
699 break;
700 }
701 }
702 }
703
704 if (!ret) {
705 if (!is_valid_signal(sig)) {
706 ret = "INVALID";
707 } else {
708 ret = "UNKNOWN";
709 }
710 }
711
712 if (out && outlen > 0) {
713 strncpy(out, ret, outlen);
714 out[outlen - 1] = '\0';
715 }
716 return out;
717 }
718
719 int os::Posix::get_signal_number(const char* signal_name) {
720 char tmp[30];
721 const char* s = signal_name;
722 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
723 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
724 s = tmp;
725 }
726 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
727 if (strcmp(g_signal_info[idx].name, s) == 0) {
728 return g_signal_info[idx].sig;
729 }
730 }
731 return -1;
732 }
733
734 int os::get_signal_number(const char* signal_name) {
735 return os::Posix::get_signal_number(signal_name);
736 }
737
738 // Returns true if signal number is valid.
739 bool os::Posix::is_valid_signal(int sig) {
740 // MacOS not really POSIX compliant: sigaddset does not return
741 // an error for invalid signal numbers. However, MacOS does not
742 // support real time signals and simply seems to have just 33
743 // signals with no holes in the signal range.
744 #ifdef __APPLE__
745 return sig >= 1 && sig < NSIG;
746 #else
747 // Use sigaddset to check for signal validity.
748 sigset_t set;
749 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
750 return false;
751 }
752 return true;
753 #endif
754 }
755
756 // Returns:
757 // NULL for an invalid signal number
758 // "SIG<num>" for a valid but unknown signal number
759 // signal name otherwise.
760 const char* os::exception_name(int sig, char* buf, size_t size) {
761 if (!os::Posix::is_valid_signal(sig)) {
762 return NULL;
763 }
764 const char* const name = os::Posix::get_signal_name(sig, buf, size);
765 if (strcmp(name, "UNKNOWN") == 0) {
766 jio_snprintf(buf, size, "SIG%d", sig);
767 }
768 return buf;
769 }
770
771 #define NUM_IMPORTANT_SIGS 32
772 // Returns one-line short description of a signal set in a user provided buffer.
773 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
774 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
775 // Note: for shortness, just print out the first 32. That should
776 // cover most of the useful ones, apart from realtime signals.
777 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
778 const int rc = sigismember(set, sig);
779 if (rc == -1 && errno == EINVAL) {
780 buffer[sig-1] = '?';
781 } else {
782 buffer[sig-1] = rc == 0 ? '0' : '1';
783 }
784 }
785 buffer[NUM_IMPORTANT_SIGS] = 0;
786 return buffer;
787 }
788
789 // Prints one-line description of a signal set.
790 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
791 char buf[NUM_IMPORTANT_SIGS + 1];
792 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
793 st->print("%s", buf);
794 }
795
796 // Writes one-line description of a combination of sigaction.sa_flags into a user
797 // provided buffer. Returns that buffer.
798 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
799 char* p = buffer;
800 size_t remaining = size;
801 bool first = true;
802 int idx = 0;
803
804 assert(buffer, "invalid argument");
805
806 if (size == 0) {
807 return buffer;
808 }
809
810 strncpy(buffer, "none", size);
811
812 const struct {
813 // NB: i is an unsigned int here because SA_RESETHAND is on some
814 // systems 0x80000000, which is implicitly unsigned. Assignining
815 // it to an int field would be an overflow in unsigned-to-signed
816 // conversion.
817 unsigned int i;
818 const char* s;
819 } flaginfo [] = {
820 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
821 { SA_ONSTACK, "SA_ONSTACK" },
822 { SA_RESETHAND, "SA_RESETHAND" },
823 { SA_RESTART, "SA_RESTART" },
824 { SA_SIGINFO, "SA_SIGINFO" },
825 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
826 { SA_NODEFER, "SA_NODEFER" },
827 #ifdef AIX
828 { SA_ONSTACK, "SA_ONSTACK" },
829 { SA_OLDSTYLE, "SA_OLDSTYLE" },
830 #endif
831 { 0, NULL }
832 };
833
834 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
835 if (flags & flaginfo[idx].i) {
836 if (first) {
837 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
838 first = false;
839 } else {
840 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
841 }
842 const size_t len = strlen(p);
843 p += len;
844 remaining -= len;
845 }
846 }
847
848 buffer[size - 1] = '\0';
849
850 return buffer;
851 }
852
853 // Prints one-line description of a combination of sigaction.sa_flags.
854 void os::Posix::print_sa_flags(outputStream* st, int flags) {
855 char buffer[0x100];
856 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
857 st->print("%s", buffer);
858 }
859
860 // Helper function for os::Posix::print_siginfo_...():
861 // return a textual description for signal code.
862 struct enum_sigcode_desc_t {
863 const char* s_name;
864 const char* s_desc;
865 };
866
867 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
868
869 const struct {
870 int sig; int code; const char* s_code; const char* s_desc;
871 } t1 [] = {
872 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
873 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
874 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
875 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
876 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
877 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
878 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
879 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
880 #if defined(IA64) && defined(LINUX)
881 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
882 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
883 #endif
884 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
885 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
886 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
887 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
888 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
889 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
890 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
891 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
892 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
893 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
894 #ifdef AIX
895 // no explanation found what keyerr would be
896 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
897 #endif
898 #if defined(IA64) && !defined(AIX)
899 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
900 #endif
901 #if defined(__sparc) && defined(SOLARIS)
902 // define Solaris Sparc M7 ADI SEGV signals
903 #if !defined(SEGV_ACCADI)
904 #define SEGV_ACCADI 3
905 #endif
906 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
907 #if !defined(SEGV_ACCDERR)
908 #define SEGV_ACCDERR 4
909 #endif
910 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
911 #if !defined(SEGV_ACCPERR)
912 #define SEGV_ACCPERR 5
913 #endif
914 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
915 #endif // defined(__sparc) && defined(SOLARIS)
916 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
917 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
918 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
919 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
920 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
921 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
922 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
923 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
924 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
925 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
926 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
927 #ifdef SIGPOLL
928 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
929 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
930 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
931 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
932 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
933 #endif
934 { -1, -1, NULL, NULL }
935 };
936
937 // Codes valid in any signal context.
938 const struct {
939 int code; const char* s_code; const char* s_desc;
940 } t2 [] = {
941 { SI_USER, "SI_USER", "Signal sent by kill()." },
942 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
943 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
944 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
945 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
946 // Linux specific
947 #ifdef SI_TKILL
948 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
949 #endif
950 #ifdef SI_DETHREAD
951 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
952 #endif
953 #ifdef SI_KERNEL
954 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
955 #endif
956 #ifdef SI_SIGIO
957 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
958 #endif
959
960 #ifdef AIX
961 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
962 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
963 #endif
964
965 #ifdef __sun
966 { SI_NOINFO, "SI_NOINFO", "No signal information" },
967 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
968 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
969 #endif
970
971 { -1, NULL, NULL }
972 };
973
974 const char* s_code = NULL;
975 const char* s_desc = NULL;
976
977 for (int i = 0; t1[i].sig != -1; i ++) {
978 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
979 s_code = t1[i].s_code;
980 s_desc = t1[i].s_desc;
981 break;
982 }
983 }
984
985 if (s_code == NULL) {
986 for (int i = 0; t2[i].s_code != NULL; i ++) {
987 if (t2[i].code == si->si_code) {
988 s_code = t2[i].s_code;
989 s_desc = t2[i].s_desc;
990 }
991 }
992 }
993
994 if (s_code == NULL) {
995 out->s_name = "unknown";
996 out->s_desc = "unknown";
997 return false;
998 }
999
1000 out->s_name = s_code;
1001 out->s_desc = s_desc;
1002
1003 return true;
1004 }
1005
1006 void os::print_siginfo(outputStream* os, const void* si0) {
1007
1008 const siginfo_t* const si = (const siginfo_t*) si0;
1009
1010 char buf[20];
1011 os->print("siginfo:");
1012
1013 if (!si) {
1014 os->print(" <null>");
1015 return;
1016 }
1017
1018 const int sig = si->si_signo;
1019
1020 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1021
1022 enum_sigcode_desc_t ed;
1023 get_signal_code_description(si, &ed);
1024 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1025
1026 if (si->si_errno) {
1027 os->print(", si_errno: %d", si->si_errno);
1028 }
1029
1030 // Output additional information depending on the signal code.
1031
1032 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1033 // so it depends on the context which member to use. For synchronous error signals,
1034 // we print si_addr, unless the signal was sent by another process or thread, in
1035 // which case we print out pid or tid of the sender.
1036 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1037 const pid_t pid = si->si_pid;
1038 os->print(", si_pid: %ld", (long) pid);
1039 if (IS_VALID_PID(pid)) {
1040 const pid_t me = getpid();
1041 if (me == pid) {
1042 os->print(" (current process)");
1043 }
1044 } else {
1045 os->print(" (invalid)");
1046 }
1047 os->print(", si_uid: %ld", (long) si->si_uid);
1048 if (sig == SIGCHLD) {
1049 os->print(", si_status: %d", si->si_status);
1050 }
1051 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1052 sig == SIGTRAP || sig == SIGFPE) {
1053 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1054 #ifdef SIGPOLL
1055 } else if (sig == SIGPOLL) {
1056 os->print(", si_band: %ld", si->si_band);
1057 #endif
1058 }
1059
1060 }
1061
1062 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1063 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1064 }
1065
1066 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1067 #if defined(AIX)
1068 return Aix::ucontext_get_pc(ctx);
1069 #elif defined(BSD)
1070 return Bsd::ucontext_get_pc(ctx);
1071 #elif defined(LINUX)
1072 return Linux::ucontext_get_pc(ctx);
1073 #elif defined(SOLARIS)
1074 return Solaris::ucontext_get_pc(ctx);
1075 #else
1076 VMError::report_and_die("unimplemented ucontext_get_pc");
1077 #endif
1078 }
1079
1080 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1081 #if defined(AIX)
1082 Aix::ucontext_set_pc(ctx, pc);
1083 #elif defined(BSD)
1084 Bsd::ucontext_set_pc(ctx, pc);
1085 #elif defined(LINUX)
1086 Linux::ucontext_set_pc(ctx, pc);
1087 #elif defined(SOLARIS)
1088 Solaris::ucontext_set_pc(ctx, pc);
1089 #else
1090 VMError::report_and_die("unimplemented ucontext_get_pc");
1091 #endif
1092 }
1093
1094 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1095 size_t stack_size = 0;
1096 size_t guard_size = 0;
1097 int detachstate = 0;
1098 pthread_attr_getstacksize(attr, &stack_size);
1099 pthread_attr_getguardsize(attr, &guard_size);
1100 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1101 LINUX_ONLY(stack_size -= guard_size);
1102 pthread_attr_getdetachstate(attr, &detachstate);
1103 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1104 stack_size / 1024, guard_size / 1024,
1105 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1106 return buf;
1107 }
1108
1109 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1110
1111 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1112 assert(false, "os::Posix::realpath: invalid arguments.");
1113 errno = EINVAL;
1114 return NULL;
1115 }
1116
1117 char* result = NULL;
1118
1119 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1120 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1121 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1122 char* p = ::realpath(filename, NULL);
1123 if (p != NULL) {
1124 if (strlen(p) < outbuflen) {
1125 strcpy(outbuf, p);
1126 result = outbuf;
1127 } else {
1128 errno = ENAMETOOLONG;
1129 }
1130 ::free(p); // *not* os::free
1131 } else {
1132 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1133 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1134 // that it complains about the NULL we handed down as user buffer.
1135 // In this case, use the user provided buffer but at least check whether realpath caused
1136 // a memory overwrite.
1137 if (errno == EINVAL) {
1138 outbuf[outbuflen - 1] = '\0';
1139 p = ::realpath(filename, outbuf);
1140 if (p != NULL) {
1141 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1142 result = p;
1143 }
1144 }
1145 }
1146 return result;
1147
1148 }
1149
1150
1151 // Check minimum allowable stack sizes for thread creation and to initialize
1152 // the java system classes, including StackOverflowError - depends on page
1153 // size.
1154 // The space needed for frames during startup is platform dependent. It
1155 // depends on word size, platform calling conventions, C frame layout and
1156 // interpreter/C1/C2 design decisions. Therefore this is given in a
1157 // platform (os/cpu) dependent constant.
1158 // To this, space for guard mechanisms is added, which depends on the
1159 // page size which again depends on the concrete system the VM is running
1160 // on. Space for libc guard pages is not included in this size.
1161 jint os::Posix::set_minimum_stack_sizes() {
1162 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1163
1164 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1165 JavaThread::stack_guard_zone_size() +
1166 JavaThread::stack_shadow_zone_size();
1167
1168 _java_thread_min_stack_allowed = align_size_up(_java_thread_min_stack_allowed, vm_page_size());
1169 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1170
1171 size_t stack_size_in_bytes = ThreadStackSize * K;
1172 if (stack_size_in_bytes != 0 &&
1173 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1174 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1175 // ThreadStackSize so we go with "Java thread stack size" instead
1176 // of "ThreadStackSize" to be more friendly.
1177 tty->print_cr("\nThe Java thread stack size specified is too small. "
1178 "Specify at least " SIZE_FORMAT "k",
1179 _java_thread_min_stack_allowed / K);
1180 return JNI_ERR;
1181 }
1182
1183 // Make the stack size a multiple of the page size so that
1184 // the yellow/red zones can be guarded.
1185 JavaThread::set_stack_size_at_create(round_to(stack_size_in_bytes, vm_page_size()));
1186
1187 // Reminder: a compiler thread is a Java thread.
1188 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1189 JavaThread::stack_guard_zone_size() +
1190 JavaThread::stack_shadow_zone_size();
1191
1192 _compiler_thread_min_stack_allowed = align_size_up(_compiler_thread_min_stack_allowed, vm_page_size());
1193 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1194
1195 stack_size_in_bytes = CompilerThreadStackSize * K;
1196 if (stack_size_in_bytes != 0 &&
1197 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1198 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1199 "Specify at least " SIZE_FORMAT "k",
1200 _compiler_thread_min_stack_allowed / K);
1201 return JNI_ERR;
1202 }
1203
1204 _vm_internal_thread_min_stack_allowed = align_size_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1205 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1206
1207 stack_size_in_bytes = VMThreadStackSize * K;
1208 if (stack_size_in_bytes != 0 &&
1209 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1210 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1211 "Specify at least " SIZE_FORMAT "k",
1212 _vm_internal_thread_min_stack_allowed / K);
1213 return JNI_ERR;
1214 }
1215 return JNI_OK;
1216 }
1217
1218 // Called when creating the thread. The minimum stack sizes have already been calculated
1219 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1220 size_t stack_size;
1221 if (req_stack_size == 0) {
1222 stack_size = default_stack_size(thr_type);
1223 } else {
1224 stack_size = req_stack_size;
1225 }
1226
1227 switch (thr_type) {
1228 case os::java_thread:
1229 // Java threads use ThreadStackSize which default value can be
1230 // changed with the flag -Xss
1231 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1232 // no requested size and we have a more specific default value
1233 stack_size = JavaThread::stack_size_at_create();
1234 }
1235 stack_size = MAX2(stack_size,
1236 _java_thread_min_stack_allowed);
1237 break;
1238 case os::compiler_thread:
1239 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1240 // no requested size and we have a more specific default value
1241 stack_size = (size_t)(CompilerThreadStackSize * K);
1242 }
1243 stack_size = MAX2(stack_size,
1244 _compiler_thread_min_stack_allowed);
1245 break;
1246 case os::vm_thread:
1247 case os::pgc_thread:
1248 case os::cgc_thread:
1249 case os::watcher_thread:
1250 default: // presume the unknown thr_type is a VM internal
1251 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1252 // no requested size and we have a more specific default value
1253 stack_size = (size_t)(VMThreadStackSize * K);
1254 }
1255
1256 stack_size = MAX2(stack_size,
1257 _vm_internal_thread_min_stack_allowed);
1258 break;
1259 }
1260
1261 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1262 // Be careful not to round up to 0. Align down in that case.
1263 if (stack_size <= SIZE_MAX - vm_page_size()) {
1264 stack_size = align_size_up(stack_size, vm_page_size());
1265 } else {
1266 stack_size = align_size_down(stack_size, vm_page_size());
1267 }
1268
1269 return stack_size;
1270 }
1271
1272 os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
1273 assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
1274 }
1275
1276 /*
1277 * See the caveats for this class in os_posix.hpp
1278 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1279 * method and returns false. If none of the signals are raised, returns true.
1280 * The callback is supposed to provide the method that should be protected.
1281 */
1282 bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1283 sigset_t saved_sig_mask;
1284
1285 assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
1286 assert(!WatcherThread::watcher_thread()->has_crash_protection(),
1287 "crash_protection already set?");
1288
1289 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1290 // since on at least some systems (OS X) siglongjmp will restore the mask
1291 // for the process, not the thread
1292 pthread_sigmask(0, NULL, &saved_sig_mask);
1293 if (sigsetjmp(_jmpbuf, 0) == 0) {
1294 // make sure we can see in the signal handler that we have crash protection
1295 // installed
1296 WatcherThread::watcher_thread()->set_crash_protection(this);
1297 cb.call();
1298 // and clear the crash protection
1299 WatcherThread::watcher_thread()->set_crash_protection(NULL);
1300 return true;
1301 }
1302 // this happens when we siglongjmp() back
1303 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1304 WatcherThread::watcher_thread()->set_crash_protection(NULL);
1305 return false;
1306 }
1307
1308 void os::WatcherThreadCrashProtection::restore() {
1309 assert(WatcherThread::watcher_thread()->has_crash_protection(),
1310 "must have crash protection");
1311
1312 siglongjmp(_jmpbuf, 1);
1313 }
1314
1315 void os::WatcherThreadCrashProtection::check_crash_protection(int sig,
1316 Thread* thread) {
1317
1318 if (thread != NULL &&
1319 thread->is_Watcher_thread() &&
1320 WatcherThread::watcher_thread()->has_crash_protection()) {
1321
1322 if (sig == SIGSEGV || sig == SIGBUS) {
1323 WatcherThread::watcher_thread()->crash_protection()->restore();
1324 }
1325 }
1326 }
1327
1328 #define check_with_errno(check_type, cond, msg) \
1329 do { \
1330 int err = errno; \
1331 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
1332 os::errno_name(err)); \
1333 } while (false)
1334
1335 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
1336 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
1337
1338 // POSIX unamed semaphores are not supported on OS X.
1339 #ifndef __APPLE__
1340
1341 PosixSemaphore::PosixSemaphore(uint value) {
1342 int ret = sem_init(&_semaphore, 0, value);
1343
1344 guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
1345 }
1346
1347 PosixSemaphore::~PosixSemaphore() {
1348 sem_destroy(&_semaphore);
1349 }
1350
1351 void PosixSemaphore::signal(uint count) {
1352 for (uint i = 0; i < count; i++) {
1353 int ret = sem_post(&_semaphore);
1354
1355 assert_with_errno(ret == 0, "sem_post failed");
1356 }
1357 }
1358
1359 void PosixSemaphore::wait() {
1360 int ret;
1361
1362 do {
1363 ret = sem_wait(&_semaphore);
1364 } while (ret != 0 && errno == EINTR);
1365
1366 assert_with_errno(ret == 0, "sem_wait failed");
1367 }
1368
1369 bool PosixSemaphore::trywait() {
1370 int ret;
1371
1372 do {
1373 ret = sem_trywait(&_semaphore);
1374 } while (ret != 0 && errno == EINTR);
1375
1376 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
1377
1378 return ret == 0;
1379 }
1380
1381 bool PosixSemaphore::timedwait(struct timespec ts) {
1382 while (true) {
1383 int result = sem_timedwait(&_semaphore, &ts);
1384 if (result == 0) {
1385 return true;
1386 } else if (errno == EINTR) {
1387 continue;
1388 } else if (errno == ETIMEDOUT) {
1389 return false;
1390 } else {
1391 assert_with_errno(false, "timedwait failed");
1392 return false;
1393 }
1394 }
1395 }
1396
1397 #endif // __APPLE__
1398
1399
1400 // Shared pthread_mutex/cond based PlatformEvent implementation.
1401 // Not currently usable by Solaris
1402
1403 #ifndef SOLARIS
1404
1405 // Shared condattr object for use with relative timed-waits. Will be associated
1406 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1407 // but otherwise whatever default is used by the platform - generally the
1408 // time-of-day clock
1409 static pthread_condattr_t _condAttr[1];
1410
1411 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1412 // all systems (e.g. FreeBSD) map the default to "normal".
1413 static pthread_mutexattr_t _mutexAttr[1];
1414
1415 // common basic initialization that is always supported
1416 static void pthread_init_common(void) {
1417 int status;
1418 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1419 fatal("pthread_condattr_init: %s", os::strerror(status));
1420 }
1421 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1422 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1423 }
1424 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1425 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1426 }
1427 }
1428
1429 // Not all POSIX types and API's are available on all notionally "posix"
1430 // platforms. If we have build-time support then we will check for actual
1431 // runtime support via dlopen/dlsym lookup. This allows for running on an
1432 // older OS version compared to the build platform. But if there is no
1433 // build time support then there can not be any runtime support as we do not
1434 // know what the runtime types would be (for example clockid_t might be an
1435 // int or int64_t.
1436 //
1437 #ifdef SUPPORTS_CLOCK_MONOTONIC
1438
1439 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1440
1441 static int (*_clock_gettime)(clockid_t, struct timespec *);
1442 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1443
1444 static bool _use_clock_monotonic_condattr;
1445
1446 // determine what POSIX API's are present and do appropriate
1447 // configuration
1448 void os::Posix::init(void) {
1449
1450 // NOTE: no logging available when this is called. Put logging
1451 // statements in init_2().
1452
1453 // copied from os::Linux::clock_init(). The duplication is temporary.
1454
1455 // 1. Check for CLOCK_MONOTONIC support
1456
1457 void* handle = NULL;
1458
1459 // For linux we need librt, for other OS we can find
1460 // this function in regular libc
1461 #ifdef NEEDS_LIBRT
1462 // we do dlopen's in this particular order due to bug in linux
1463 // dynamical loader (see 6348968) leading to crash on exit
1464 handle = dlopen("librt.so.1", RTLD_LAZY);
1465 if (handle == NULL) {
1466 handle = dlopen("librt.so", RTLD_LAZY);
1467 }
1468 #endif
1469
1470 if (handle == NULL) {
1471 handle = RTLD_DEFAULT;
1472 }
1473
1474 _clock_gettime = NULL;
1475
1476 int (*clock_getres_func)(clockid_t, struct timespec*) =
1477 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1478 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1479 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1480 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1481 // we assume that if both clock_gettime and clock_getres support
1482 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock
1483 struct timespec res;
1484 struct timespec tp;
1485 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1486 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1487 // yes, monotonic clock is supported
1488 _clock_gettime = clock_gettime_func;
1489 } else {
1490 #ifdef NEEDS_LIBRT
1491 // close librt if there is no monotonic clock
1492 if (handle != RTLD_DEFAULT) {
1493 dlclose(handle);
1494 }
1495 #endif
1496 }
1497 }
1498
1499 // 2. Check for pthread_condattr_setclock support
1500
1501 _pthread_condattr_setclock = NULL;
1502
1503 // libpthread is already loaded
1504 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1505 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1506 "pthread_condattr_setclock");
1507 if (condattr_setclock_func != NULL) {
1508 _pthread_condattr_setclock = condattr_setclock_func;
1509 }
1510
1511 // Now do general initialization
1512
1513 pthread_init_common();
1514
1515 int status;
1516 if (_pthread_condattr_setclock != NULL &&
1517 _clock_gettime != NULL) {
1518 _use_clock_monotonic_condattr = true;
1519
1520 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1521 if (status == EINVAL) {
1522 _use_clock_monotonic_condattr = false;
1523 warning("Unable to use monotonic clock with relative timed-waits" \
1524 " - changes to the time-of-day clock may have adverse affects");
1525 } else {
1526 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1527 }
1528 }
1529 }
1530 else {
1531 _use_clock_monotonic_condattr = false;
1532 }
1533 }
1534
1535 void os::Posix::init_2(void) {
1536 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1537 (_clock_gettime != NULL ? "" : " not"));
1538 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1539 (_pthread_condattr_setclock != NULL ? "" : " not"));
1540 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1541 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1542 }
1543
1544 #else // !SUPPORTS_CLOCK_MONOTONIC
1545
1546 void os::Posix::init(void) {
1547 pthread_init_common();
1548 }
1549
1550 void os::Posix::init_2(void) {
1551 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1552 log_info(os)("Use of pthread_condattr_setclock is not supported");
1553 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1554 }
1555
1556 #endif // SUPPORTS_CLOCK_MONOTONIC
1557
1558 os::PlatformEvent::PlatformEvent() {
1559 int status = pthread_cond_init(_cond, _condAttr);
1560 assert_status(status == 0, status, "cond_init");
1561 status = pthread_mutex_init(_mutex, _mutexAttr);
1562 assert_status(status == 0, status, "mutex_init");
1563 _event = 0;
1564 _nParked = 0;
1565 }
1566
1567 // Utility to convert the given timeout to an absolute timespec
1568 // (based on the appropriate clock) to use with pthread_cond_timewait.
1569 // The clock queried here must be the clock used to manage the
1570 // timeout of the condition variable.
1571 //
1572 // The passed in timeout value is either a relative time in nanoseconds
1573 // or an absolute time in milliseconds. A relative timeout will be
1574 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1575 // the default time-of-day clock will be used.
1576
1577 // Given time is a 64-bit value and the time_t used in the timespec is
1578 // sometimes a signed-32-bit value we have to watch for overflow if times
1579 // way in the future are given. Further on Solaris versions
1580 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1581 // number of seconds, in abstime, is less than current_time + 100,000,000.
1582 // As it will be over 20 years before "now + 100000000" will overflow we can
1583 // ignore overflow and just impose a hard-limit on seconds using the value
1584 // of "now + 100,000,000". This places a limit on the timeout of about 3.17
1585 // years from "now".
1586 //
1587 #define MAX_SECS 100000000
1588
1589 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1590
1591 if (timeout < 0)
1592 timeout = 0;
1593
1594 time_t max_secs = 0;
1595
1596 #ifdef SUPPORTS_CLOCK_MONOTONIC
1597
1598 if (_use_clock_monotonic_condattr && !isAbsolute) {
1599 // relative timeout in nanoseconds
1600 jlong seconds = timeout / NANOUNITS;
1601 timeout %= NANOUNITS; // remaining nanos
1602
1603 struct timespec now;
1604 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1605 assert_status(status == 0, status, "clock_gettime");
1606
1607 max_secs = now.tv_sec + MAX_SECS;
1608 if (seconds >= MAX_SECS) {
1609 // More seconds than we can add, so pin to max_secs
1610 abstime->tv_sec = max_secs;
1611 abstime->tv_nsec = 0;
1612 }
1613 else {
1614 abstime->tv_sec = now.tv_sec + seconds;
1615 long nsecs = now.tv_nsec + timeout;
1616 if (nsecs >= NANOUNITS) { // overflow
1617 abstime->tv_sec += 1;
1618 nsecs -= NANOUNITS;
1619 }
1620 abstime->tv_nsec = nsecs;
1621 }
1622 }
1623 else {
1624
1625 #else
1626
1627 { // match the block scope
1628
1629 #endif // SUPPORTS_CLOCK_MONOTONIC
1630
1631 // time-of-day clock is all we can reliably use
1632 struct timeval now;
1633 int status = gettimeofday(&now, NULL);
1634 assert(status == 0, "gettimeofday");
1635 max_secs = now.tv_sec + MAX_SECS;
1636
1637 if (isAbsolute) {
1638 // absolute timeout in milliseconds
1639 jlong seconds = timeout / MILLIUNITS;
1640 timeout %= MILLIUNITS; // remaining millis
1641
1642 if (seconds >= max_secs) {
1643 // Absolue seconds exceeds allow max, so pin to max_secs
1644 abstime->tv_sec = max_secs;
1645 abstime->tv_nsec = 0;
1646 }
1647 else {
1648 abstime->tv_sec = seconds;
1649 abstime->tv_nsec = timeout * (NANOUNITS/MILLIUNITS);
1650 }
1651 }
1652 else {
1653 // relative timeout in nanoseconds
1654 jlong seconds = timeout / NANOUNITS;
1655 timeout %= NANOUNITS; // remaining nanos
1656
1657 if (seconds >= MAX_SECS) {
1658 // More seconds than we can add, so pin to max_secs
1659 abstime->tv_sec = max_secs;
1660 abstime->tv_nsec = 0;
1661 }
1662 else {
1663 abstime->tv_sec = now.tv_sec + seconds;
1664 jlong micros_left = timeout / (NANOUNITS/MICROUNITS);
1665 long usec = now.tv_usec + micros_left;
1666 if (usec >= MICROUNITS) { // overflow
1667 abstime->tv_sec += 1;
1668 usec -= MICROUNITS;
1669 }
1670 abstime->tv_nsec = usec * (NANOUNITS/MICROUNITS);
1671 }
1672 }
1673 }
1674
1675 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1676 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1677 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1678 assert(abstime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
1679
1680 }
1681
1682 // PlatformEvent
1683 //
1684 // Assumption:
1685 // Only one parker can exist on an event, which is why we allocate
1686 // them per-thread. Multiple unparkers can coexist.
1687 //
1688 // _event serves as a restricted-range semaphore.
1689 // -1 : thread is blocked, i.e. there is a waiter
1690 // 0 : neutral: thread is running or ready,
1691 // could have been signaled after a wait started
1692 // 1 : signaled - thread is running or ready
1693 //
1694 // Having three states allows for some detection of bad usage - see
1695 // comments on unpark().
1696
1697 void os::PlatformEvent::park() { // AKA "down()"
1698 // Transitions for _event:
1699 // -1 => -1 : illegal
1700 // 1 => 0 : pass - return immediately
1701 // 0 => -1 : block; then set _event to 0 before returning
1702
1703 // Invariant: Only the thread associated with the PlatformEvent
1704 // may call park().
1705 assert(_nParked == 0, "invariant");
1706
1707 int v;
1708
1709 // atomically decrement _event
1710 for (;;) {
1711 v = _event;
1712 if (Atomic::cmpxchg(v-1, &_event, v) == v) break;
1713 }
1714 guarantee(v >= 0, "invariant");
1715
1716 if (v == 0) { // Do this the hard way by blocking ...
1717 int status = pthread_mutex_lock(_mutex);
1718 assert_status(status == 0, status, "mutex_lock");
1719 guarantee(_nParked == 0, "invariant");
1720 ++_nParked;
1721 while (_event < 0) {
1722 // OS-level "spurious wakeups" are ignored
1723 status = pthread_cond_wait(_cond, _mutex);
1724 assert_status(status == 0, status, "cond_wait");
1725 }
1726 --_nParked;
1727
1728 _event = 0;
1729 status = pthread_mutex_unlock(_mutex);
1730 assert_status(status == 0, status, "mutex_unlock");
1731 // Paranoia to ensure our locked and lock-free paths interact
1732 // correctly with each other.
1733 OrderAccess::fence();
1734 }
1735 guarantee(_event >= 0, "invariant");
1736 }
1737
1738 int os::PlatformEvent::park(jlong millis) {
1739 // Transitions for _event:
1740 // -1 => -1 : illegal
1741 // 1 => 0 : pass - return immediately
1742 // 0 => -1 : block; then set _event to 0 before returning
1743
1744 // Invariant: Only the thread associated with the Event/PlatformEvent
1745 // may call park().
1746 assert(_nParked == 0, "invariant");
1747
1748 int v;
1749 // atomically decrement _event
1750 for (;;) {
1751 v = _event;
1752 if (Atomic::cmpxchg(v-1, &_event, v) == v) break;
1753 }
1754 guarantee(v >= 0, "invariant");
1755
1756 if (v == 0) { // Do this the hard way by blocking ...
1757 struct timespec abst;
1758 to_abstime(&abst, millis * (NANOUNITS/MILLIUNITS), false);
1759
1760 int ret = OS_TIMEOUT;
1761 int status = pthread_mutex_lock(_mutex);
1762 assert_status(status == 0, status, "mutex_lock");
1763 guarantee(_nParked == 0, "invariant");
1764 ++_nParked;
1765
1766 while (_event < 0) {
1767 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1768 assert_status(status == 0 || status == ETIMEDOUT,
1769 status, "cond_timedwait");
1770 // OS-level "spurious wakeups" are ignored unless the archaic
1771 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1772 if (!FilterSpuriousWakeups) break;
1773 if (status == ETIMEDOUT) break;
1774 }
1775 --_nParked;
1776
1777 if (_event >= 0) {
1778 ret = OS_OK;
1779 }
1780
1781 _event = 0;
1782 status = pthread_mutex_unlock(_mutex);
1783 assert_status(status == 0, status, "mutex_unlock");
1784 // Paranoia to ensure our locked and lock-free paths interact
1785 // correctly with each other.
1786 OrderAccess::fence();
1787 return ret;
1788 }
1789 return OS_OK;
1790 }
1791
1792 void os::PlatformEvent::unpark() {
1793 // Transitions for _event:
1794 // 0 => 1 : just return
1795 // 1 => 1 : just return
1796 // -1 => either 0 or 1; must signal target thread
1797 // That is, we can safely transition _event from -1 to either
1798 // 0 or 1.
1799 // See also: "Semaphores in Plan 9" by Mullender & Cox
1800 //
1801 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1802 // that it will take two back-to-back park() calls for the owning
1803 // thread to block. This has the benefit of forcing a spurious return
1804 // from the first park() call after an unpark() call which will help
1805 // shake out uses of park() and unpark() without checking state conditions
1806 // properly. This spurious return doesn't manifest itself in any user code
1807 // but only in the correctly written condition checking loops of ObjectMonitor,
1808 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1809
1810 if (Atomic::xchg(1, &_event) >= 0) return;
1811
1812 int status = pthread_mutex_lock(_mutex);
1813 assert_status(status == 0, status, "mutex_lock");
1814 int anyWaiters = _nParked;
1815 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1816 status = pthread_mutex_unlock(_mutex);
1817 assert_status(status == 0, status, "mutex_unlock");
1818
1819 // Note that we signal() *after* dropping the lock for "immortal" Events.
1820 // This is safe and avoids a common class of futile wakeups. In rare
1821 // circumstances this can cause a thread to return prematurely from
1822 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1823 // will simply re-test the condition and re-park itself.
1824 // This provides particular benefit if the underlying platform does not
1825 // provide wait morphing.
1826
1827 if (anyWaiters != 0) {
1828 status = pthread_cond_signal(_cond);
1829 assert_status(status == 0, status, "cond_signal");
1830 }
1831 }
1832
1833 // JSR166 support
1834
1835 os::PlatformParker::PlatformParker() {
1836 int status;
1837 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1838 assert_status(status == 0, status, "cond_init rel");
1839 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
1840 assert_status(status == 0, status, "cond_init abs");
1841 status = pthread_mutex_init(_mutex, _mutexAttr);
1842 assert_status(status == 0, status, "mutex_init");
1843 _cur_index = -1; // mark as unused
1844 }
1845
1846 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
1847 // sets count to 1 and signals condvar. Only one thread ever waits
1848 // on the condvar. Contention seen when trying to park implies that someone
1849 // is unparking you, so don't wait. And spurious returns are fine, so there
1850 // is no need to track notifications.
1851
1852 void Parker::park(bool isAbsolute, jlong time) {
1853
1854 // Optional fast-path check:
1855 // Return immediately if a permit is available.
1856 // We depend on Atomic::xchg() having full barrier semantics
1857 // since we are doing a lock-free update to _counter.
1858 if (Atomic::xchg(0, &_counter) > 0) return;
1859
1860 Thread* thread = Thread::current();
1861 assert(thread->is_Java_thread(), "Must be JavaThread");
1862 JavaThread *jt = (JavaThread *)thread;
1863
1864 // Optional optimization -- avoid state transitions if there's
1865 // an interrupt pending.
1866 if (Thread::is_interrupted(thread, false)) {
1867 return;
1868 }
1869
1870 // Next, demultiplex/decode time arguments
1871 struct timespec absTime;
1872 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
1873 return;
1874 }
1875 if (time > 0) {
1876 to_abstime(&absTime, time, isAbsolute);
1877 }
1878
1879 // Enter safepoint region
1880 // Beware of deadlocks such as 6317397.
1881 // The per-thread Parker:: mutex is a classic leaf-lock.
1882 // In particular a thread must never block on the Threads_lock while
1883 // holding the Parker:: mutex. If safepoints are pending both the
1884 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
1885 ThreadBlockInVM tbivm(jt);
1886
1887 // Don't wait if cannot get lock since interference arises from
1888 // unparking. Also re-check interrupt before trying wait.
1889 if (Thread::is_interrupted(thread, false) ||
1890 pthread_mutex_trylock(_mutex) != 0) {
1891 return;
1892 }
1893
1894 int status;
1895 if (_counter > 0) { // no wait needed
1896 _counter = 0;
1897 status = pthread_mutex_unlock(_mutex);
1898 assert_status(status == 0, status, "invariant");
1899 // Paranoia to ensure our locked and lock-free paths interact
1900 // correctly with each other and Java-level accesses.
1901 OrderAccess::fence();
1902 return;
1903 }
1904
1905 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
1906 jt->set_suspend_equivalent();
1907 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1908
1909 assert(_cur_index == -1, "invariant");
1910 if (time == 0) {
1911 _cur_index = REL_INDEX; // arbitrary choice when not timed
1912 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
1913 assert_status(status == 0, status, "cond_timedwait");
1914 }
1915 else {
1916 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
1917 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
1918 assert_status(status == 0 || status == ETIMEDOUT,
1919 status, "cond_timedwait");
1920 }
1921 _cur_index = -1;
1922
1923 _counter = 0;
1924 status = pthread_mutex_unlock(_mutex);
1925 assert_status(status == 0, status, "invariant");
1926 // Paranoia to ensure our locked and lock-free paths interact
1927 // correctly with each other and Java-level accesses.
1928 OrderAccess::fence();
1929
1930 // If externally suspended while waiting, re-suspend
1931 if (jt->handle_special_suspend_equivalent_condition()) {
1932 jt->java_suspend_self();
1933 }
1934 }
1935
1936 void Parker::unpark() {
1937 int status = pthread_mutex_lock(_mutex);
1938 assert_status(status == 0, status, "invariant");
1939 const int s = _counter;
1940 _counter = 1;
1941 // must capture correct index before unlocking
1942 int index = _cur_index;
1943 status = pthread_mutex_unlock(_mutex);
1944 assert_status(status == 0, status, "invariant");
1945
1946 // Note that we signal() *after* dropping the lock for "immortal" Events.
1947 // This is safe and avoids a common class of futile wakeups. In rare
1948 // circumstances this can cause a thread to return prematurely from
1949 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1950 // will simply re-test the condition and re-park itself.
1951 // This provides particular benefit if the underlying platform does not
1952 // provide wait morphing.
1953
1954 if (s < 1 && index != -1) {
1955 // thread is definitely parked
1956 status = pthread_cond_signal(&_cond[index]);
1957 assert_status(status == 0, status, "invariant");
1958 }
1959 }
1960
1961
1962 #endif // !SOLARIS