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/align.hpp"
32 #include "utilities/macros.hpp"
33 #include "utilities/vmError.hpp"
34
35 #include <dlfcn.h>
36 #include <pthread.h>
37 #include <semaphore.h>
38 #include <signal.h>
39 #include <sys/resource.h>
40 #include <sys/utsname.h>
41 #include <time.h>
42 #include <unistd.h>
43
44 // Todo: provide a os::get_max_process_id() or similar. Number of processes
45 // may have been configured, can be read more accurately from proc fs etc.
46 #ifndef MAX_PID
47 #define MAX_PID INT_MAX
48 #endif
49 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
50
51 // Check core dump limit and report possible place where core can be found
52 void os::check_dump_limit(char* buffer, size_t bufferSize) {
53 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) {
54 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line");
55 VMError::record_coredump_status(buffer, false);
56 return;
57 }
58
59 int n;
60 struct rlimit rlim;
61 bool success;
62
63 char core_path[PATH_MAX];
64 n = get_core_path(core_path, PATH_MAX);
65
66 if (n <= 0) {
67 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());
68 success = true;
69 #ifdef LINUX
70 } else if (core_path[0] == '"') { // redirect to user process
71 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);
72 success = true;
73 #endif
74 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
75 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);
76 success = true;
77 } else {
78 switch(rlim.rlim_cur) {
79 case RLIM_INFINITY:
80 jio_snprintf(buffer, bufferSize, "%s", core_path);
81 success = true;
82 break;
83 case 0:
84 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
85 success = false;
86 break;
87 default:
88 jio_snprintf(buffer, bufferSize, "%s (max size " UINT64_FORMAT " kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, uint64_t(rlim.rlim_cur) / 1024);
89 success = true;
90 break;
91 }
92 }
93
94 VMError::record_coredump_status(buffer, success);
95 }
96
97 int os::get_native_stack(address* stack, int frames, int toSkip) {
98 int frame_idx = 0;
99 int num_of_frames; // number of frames captured
100 frame fr = os::current_frame();
101 while (fr.pc() && frame_idx < frames) {
102 if (toSkip > 0) {
103 toSkip --;
104 } else {
105 stack[frame_idx ++] = fr.pc();
106 }
107 if (fr.fp() == NULL || fr.cb() != NULL ||
108 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;
109
110 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
111 fr = os::get_sender_for_C_frame(&fr);
112 } else {
113 break;
114 }
115 }
116 num_of_frames = frame_idx;
117 for (; frame_idx < frames; frame_idx ++) {
118 stack[frame_idx] = NULL;
119 }
120
121 return num_of_frames;
122 }
123
124
125 bool os::unsetenv(const char* name) {
126 assert(name != NULL, "Null pointer");
127 return (::unsetenv(name) == 0);
128 }
129
130 int os::get_last_error() {
131 return errno;
132 }
133
134 bool os::is_debugger_attached() {
135 // not implemented
136 return false;
137 }
138
139 void os::wait_for_keypress_at_exit(void) {
140 // don't do anything on posix platforms
141 return;
142 }
143
144 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
145 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
146 // rather than unmapping and remapping the whole chunk to get requested alignment.
147 char* os::reserve_memory_aligned(size_t size, size_t alignment) {
148 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
149 "Alignment must be a multiple of allocation granularity (page size)");
150 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
151
152 size_t extra_size = size + alignment;
153 assert(extra_size >= size, "overflow, size is too large to allow alignment");
154
155 char* extra_base = os::reserve_memory(extra_size, NULL, alignment);
156
157 if (extra_base == NULL) {
158 return NULL;
159 }
160
161 // Do manual alignment
162 char* aligned_base = align_up(extra_base, alignment);
163
164 // [ | | ]
165 // ^ extra_base
166 // ^ extra_base + begin_offset == aligned_base
167 // extra_base + begin_offset + size ^
168 // extra_base + extra_size ^
169 // |<>| == begin_offset
170 // end_offset == |<>|
171 size_t begin_offset = aligned_base - extra_base;
172 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
173
174 if (begin_offset > 0) {
175 os::release_memory(extra_base, begin_offset);
176 }
177
178 if (end_offset > 0) {
179 os::release_memory(extra_base + begin_offset + size, end_offset);
180 }
181
182 return aligned_base;
183 }
184
185 int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
186 return vsnprintf(buf, len, fmt, args);
187 }
188
189 int os::get_fileno(FILE* fp) {
190 return NOT_AIX(::)fileno(fp);
191 }
192
193 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
194 return gmtime_r(clock, res);
195 }
196
197 void os::Posix::print_load_average(outputStream* st) {
198 st->print("load average:");
199 double loadavg[3];
200 os::loadavg(loadavg, 3);
201 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
202 st->cr();
203 }
204
205 void os::Posix::print_rlimit_info(outputStream* st) {
206 st->print("rlimit:");
207 struct rlimit rlim;
208
209 st->print(" STACK ");
210 getrlimit(RLIMIT_STACK, &rlim);
211 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
212 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
213
214 st->print(", CORE ");
215 getrlimit(RLIMIT_CORE, &rlim);
216 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
217 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
218
219 // Isn't there on solaris
220 #if defined(AIX)
221 st->print(", NPROC ");
222 st->print("%d", sysconf(_SC_CHILD_MAX));
223 #elif !defined(SOLARIS)
224 st->print(", NPROC ");
225 getrlimit(RLIMIT_NPROC, &rlim);
226 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
227 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
228 #endif
229
230 st->print(", NOFILE ");
231 getrlimit(RLIMIT_NOFILE, &rlim);
232 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
233 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
234
235 st->print(", AS ");
236 getrlimit(RLIMIT_AS, &rlim);
237 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
238 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
239
240 st->print(", DATA ");
241 getrlimit(RLIMIT_DATA, &rlim);
242 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
243 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
244
245 st->print(", FSIZE ");
246 getrlimit(RLIMIT_FSIZE, &rlim);
247 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
248 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
249
250 st->cr();
251 }
252
253 void os::Posix::print_uname_info(outputStream* st) {
254 // kernel
255 st->print("uname:");
256 struct utsname name;
257 uname(&name);
258 st->print("%s ", name.sysname);
259 #ifdef ASSERT
260 st->print("%s ", name.nodename);
261 #endif
262 st->print("%s ", name.release);
263 st->print("%s ", name.version);
264 st->print("%s", name.machine);
265 st->cr();
266 }
267
268 bool os::get_host_name(char* buf, size_t buflen) {
269 struct utsname name;
270 uname(&name);
271 jio_snprintf(buf, buflen, "%s", name.nodename);
272 return true;
273 }
274
275 bool os::has_allocatable_memory_limit(julong* limit) {
276 struct rlimit rlim;
277 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
278 // if there was an error when calling getrlimit, assume that there is no limitation
279 // on virtual memory.
280 bool result;
281 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
282 result = false;
283 } else {
284 *limit = (julong)rlim.rlim_cur;
285 result = true;
286 }
287 #ifdef _LP64
288 return result;
289 #else
290 // arbitrary virtual space limit for 32 bit Unices found by testing. If
291 // getrlimit above returned a limit, bound it with this limit. Otherwise
292 // directly use it.
293 const julong max_virtual_limit = (julong)3800*M;
294 if (result) {
295 *limit = MIN2(*limit, max_virtual_limit);
296 } else {
297 *limit = max_virtual_limit;
298 }
299
300 // bound by actually allocatable memory. The algorithm uses two bounds, an
301 // upper and a lower limit. The upper limit is the current highest amount of
302 // memory that could not be allocated, the lower limit is the current highest
303 // amount of memory that could be allocated.
304 // The algorithm iteratively refines the result by halving the difference
305 // between these limits, updating either the upper limit (if that value could
306 // not be allocated) or the lower limit (if the that value could be allocated)
307 // until the difference between these limits is "small".
308
309 // the minimum amount of memory we care about allocating.
310 const julong min_allocation_size = M;
311
312 julong upper_limit = *limit;
313
314 // first check a few trivial cases
315 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
316 *limit = upper_limit;
317 } else if (!is_allocatable(min_allocation_size)) {
318 // we found that not even min_allocation_size is allocatable. Return it
319 // anyway. There is no point to search for a better value any more.
320 *limit = min_allocation_size;
321 } else {
322 // perform the binary search.
323 julong lower_limit = min_allocation_size;
324 while ((upper_limit - lower_limit) > min_allocation_size) {
325 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
326 temp_limit = align_down(temp_limit, min_allocation_size);
327 if (is_allocatable(temp_limit)) {
328 lower_limit = temp_limit;
329 } else {
330 upper_limit = temp_limit;
331 }
332 }
333 *limit = lower_limit;
334 }
335 return true;
336 #endif
337 }
338
339 const char* os::get_current_directory(char *buf, size_t buflen) {
340 return getcwd(buf, buflen);
341 }
342
343 FILE* os::open(int fd, const char* mode) {
344 return ::fdopen(fd, mode);
345 }
346
347 void os::flockfile(FILE* fp) {
348 ::flockfile(fp);
349 }
350
351 void os::funlockfile(FILE* fp) {
352 ::funlockfile(fp);
353 }
354
355 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
356 // which is used to find statically linked in agents.
357 // Parameters:
358 // sym_name: Symbol in library we are looking for
359 // lib_name: Name of library to look in, NULL for shared libs.
360 // is_absolute_path == true if lib_name is absolute path to agent
361 // such as "/a/b/libL.so"
362 // == false if only the base name of the library is passed in
363 // such as "L"
364 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
365 bool is_absolute_path) {
366 char *agent_entry_name;
367 size_t len;
368 size_t name_len;
369 size_t prefix_len = strlen(JNI_LIB_PREFIX);
370 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
371 const char *start;
372
373 if (lib_name != NULL) {
374 name_len = strlen(lib_name);
375 if (is_absolute_path) {
376 // Need to strip path, prefix and suffix
377 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
378 lib_name = ++start;
379 }
380 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
381 return NULL;
382 }
383 lib_name += prefix_len;
384 name_len = strlen(lib_name) - suffix_len;
385 }
386 }
387 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
388 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
389 if (agent_entry_name == NULL) {
390 return NULL;
391 }
392 strcpy(agent_entry_name, sym_name);
393 if (lib_name != NULL) {
394 strcat(agent_entry_name, "_");
395 strncat(agent_entry_name, lib_name, name_len);
396 }
397 return agent_entry_name;
398 }
399
400 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
401 assert(thread == Thread::current(), "thread consistency check");
402
403 ParkEvent * const slp = thread->_SleepEvent ;
404 slp->reset() ;
405 OrderAccess::fence() ;
406
407 if (interruptible) {
408 jlong prevtime = javaTimeNanos();
409
410 for (;;) {
411 if (os::is_interrupted(thread, true)) {
412 return OS_INTRPT;
413 }
414
415 jlong newtime = javaTimeNanos();
416
417 if (newtime - prevtime < 0) {
418 // time moving backwards, should only happen if no monotonic clock
419 // not a guarantee() because JVM should not abort on kernel/glibc bugs
420 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
421 } else {
422 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
423 }
424
425 if (millis <= 0) {
426 return OS_OK;
427 }
428
429 prevtime = newtime;
430
431 {
432 assert(thread->is_Java_thread(), "sanity check");
433 JavaThread *jt = (JavaThread *) thread;
434 ThreadBlockInVM tbivm(jt);
435 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
436
437 jt->set_suspend_equivalent();
438 // cleared by handle_special_suspend_equivalent_condition() or
439 // java_suspend_self() via check_and_wait_while_suspended()
440
441 slp->park(millis);
442
443 // were we externally suspended while we were waiting?
444 jt->check_and_wait_while_suspended();
445 }
446 }
447 } else {
448 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
449 jlong prevtime = javaTimeNanos();
450
451 for (;;) {
452 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
453 // the 1st iteration ...
454 jlong newtime = javaTimeNanos();
455
456 if (newtime - prevtime < 0) {
457 // time moving backwards, should only happen if no monotonic clock
458 // not a guarantee() because JVM should not abort on kernel/glibc bugs
459 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
460 } else {
461 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
462 }
463
464 if (millis <= 0) break ;
465
466 prevtime = newtime;
467 slp->park(millis);
468 }
469 return OS_OK ;
470 }
471 }
472
473 ////////////////////////////////////////////////////////////////////////////////
474 // interrupt support
475
476 void os::interrupt(Thread* thread) {
477 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
478 "possibility of dangling Thread pointer");
479
480 OSThread* osthread = thread->osthread();
481
482 if (!osthread->interrupted()) {
483 osthread->set_interrupted(true);
484 // More than one thread can get here with the same value of osthread,
485 // resulting in multiple notifications. We do, however, want the store
486 // to interrupted() to be visible to other threads before we execute unpark().
487 OrderAccess::fence();
488 ParkEvent * const slp = thread->_SleepEvent ;
489 if (slp != NULL) slp->unpark() ;
490 }
491
492 // For JSR166. Unpark even if interrupt status already was set
493 if (thread->is_Java_thread())
494 ((JavaThread*)thread)->parker()->unpark();
495
496 ParkEvent * ev = thread->_ParkEvent ;
497 if (ev != NULL) ev->unpark() ;
498
499 }
500
501 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
502 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
503 "possibility of dangling Thread pointer");
504
505 OSThread* osthread = thread->osthread();
506
507 bool interrupted = osthread->interrupted();
508
509 // NOTE that since there is no "lock" around the interrupt and
510 // is_interrupted operations, there is the possibility that the
511 // interrupted flag (in osThread) will be "false" but that the
512 // low-level events will be in the signaled state. This is
513 // intentional. The effect of this is that Object.wait() and
514 // LockSupport.park() will appear to have a spurious wakeup, which
515 // is allowed and not harmful, and the possibility is so rare that
516 // it is not worth the added complexity to add yet another lock.
517 // For the sleep event an explicit reset is performed on entry
518 // to os::sleep, so there is no early return. It has also been
519 // recommended not to put the interrupted flag into the "event"
520 // structure because it hides the issue.
521 if (interrupted && clear_interrupted) {
522 osthread->set_interrupted(false);
523 // consider thread->_SleepEvent->reset() ... optional optimization
524 }
525
526 return interrupted;
527 }
528
529
530
531 static const struct {
532 int sig; const char* name;
533 }
534 g_signal_info[] =
535 {
536 { SIGABRT, "SIGABRT" },
537 #ifdef SIGAIO
538 { SIGAIO, "SIGAIO" },
539 #endif
540 { SIGALRM, "SIGALRM" },
541 #ifdef SIGALRM1
542 { SIGALRM1, "SIGALRM1" },
543 #endif
544 { SIGBUS, "SIGBUS" },
545 #ifdef SIGCANCEL
546 { SIGCANCEL, "SIGCANCEL" },
547 #endif
548 { SIGCHLD, "SIGCHLD" },
549 #ifdef SIGCLD
550 { SIGCLD, "SIGCLD" },
551 #endif
552 { SIGCONT, "SIGCONT" },
553 #ifdef SIGCPUFAIL
554 { SIGCPUFAIL, "SIGCPUFAIL" },
555 #endif
556 #ifdef SIGDANGER
557 { SIGDANGER, "SIGDANGER" },
558 #endif
559 #ifdef SIGDIL
560 { SIGDIL, "SIGDIL" },
561 #endif
562 #ifdef SIGEMT
563 { SIGEMT, "SIGEMT" },
564 #endif
565 { SIGFPE, "SIGFPE" },
566 #ifdef SIGFREEZE
567 { SIGFREEZE, "SIGFREEZE" },
568 #endif
569 #ifdef SIGGFAULT
570 { SIGGFAULT, "SIGGFAULT" },
571 #endif
572 #ifdef SIGGRANT
573 { SIGGRANT, "SIGGRANT" },
574 #endif
575 { SIGHUP, "SIGHUP" },
576 { SIGILL, "SIGILL" },
577 { SIGINT, "SIGINT" },
578 #ifdef SIGIO
579 { SIGIO, "SIGIO" },
580 #endif
581 #ifdef SIGIOINT
582 { SIGIOINT, "SIGIOINT" },
583 #endif
584 #ifdef SIGIOT
585 // SIGIOT is there for BSD compatibility, but on most Unices just a
586 // synonym for SIGABRT. The result should be "SIGABRT", not
587 // "SIGIOT".
588 #if (SIGIOT != SIGABRT )
589 { SIGIOT, "SIGIOT" },
590 #endif
591 #endif
592 #ifdef SIGKAP
593 { SIGKAP, "SIGKAP" },
594 #endif
595 { SIGKILL, "SIGKILL" },
596 #ifdef SIGLOST
597 { SIGLOST, "SIGLOST" },
598 #endif
599 #ifdef SIGLWP
600 { SIGLWP, "SIGLWP" },
601 #endif
602 #ifdef SIGLWPTIMER
603 { SIGLWPTIMER, "SIGLWPTIMER" },
604 #endif
605 #ifdef SIGMIGRATE
606 { SIGMIGRATE, "SIGMIGRATE" },
607 #endif
608 #ifdef SIGMSG
609 { SIGMSG, "SIGMSG" },
610 #endif
611 { SIGPIPE, "SIGPIPE" },
612 #ifdef SIGPOLL
613 { SIGPOLL, "SIGPOLL" },
614 #endif
615 #ifdef SIGPRE
616 { SIGPRE, "SIGPRE" },
617 #endif
618 { SIGPROF, "SIGPROF" },
619 #ifdef SIGPTY
620 { SIGPTY, "SIGPTY" },
621 #endif
622 #ifdef SIGPWR
623 { SIGPWR, "SIGPWR" },
624 #endif
625 { SIGQUIT, "SIGQUIT" },
626 #ifdef SIGRECONFIG
627 { SIGRECONFIG, "SIGRECONFIG" },
628 #endif
629 #ifdef SIGRECOVERY
630 { SIGRECOVERY, "SIGRECOVERY" },
631 #endif
632 #ifdef SIGRESERVE
633 { SIGRESERVE, "SIGRESERVE" },
634 #endif
635 #ifdef SIGRETRACT
636 { SIGRETRACT, "SIGRETRACT" },
637 #endif
638 #ifdef SIGSAK
639 { SIGSAK, "SIGSAK" },
640 #endif
641 { SIGSEGV, "SIGSEGV" },
642 #ifdef SIGSOUND
643 { SIGSOUND, "SIGSOUND" },
644 #endif
645 #ifdef SIGSTKFLT
646 { SIGSTKFLT, "SIGSTKFLT" },
647 #endif
648 { SIGSTOP, "SIGSTOP" },
649 { SIGSYS, "SIGSYS" },
650 #ifdef SIGSYSERROR
651 { SIGSYSERROR, "SIGSYSERROR" },
652 #endif
653 #ifdef SIGTALRM
654 { SIGTALRM, "SIGTALRM" },
655 #endif
656 { SIGTERM, "SIGTERM" },
657 #ifdef SIGTHAW
658 { SIGTHAW, "SIGTHAW" },
659 #endif
660 { SIGTRAP, "SIGTRAP" },
661 #ifdef SIGTSTP
662 { SIGTSTP, "SIGTSTP" },
663 #endif
664 { SIGTTIN, "SIGTTIN" },
665 { SIGTTOU, "SIGTTOU" },
666 #ifdef SIGURG
667 { SIGURG, "SIGURG" },
668 #endif
669 { SIGUSR1, "SIGUSR1" },
670 { SIGUSR2, "SIGUSR2" },
671 #ifdef SIGVIRT
672 { SIGVIRT, "SIGVIRT" },
673 #endif
674 { SIGVTALRM, "SIGVTALRM" },
675 #ifdef SIGWAITING
676 { SIGWAITING, "SIGWAITING" },
677 #endif
678 #ifdef SIGWINCH
679 { SIGWINCH, "SIGWINCH" },
680 #endif
681 #ifdef SIGWINDOW
682 { SIGWINDOW, "SIGWINDOW" },
683 #endif
684 { SIGXCPU, "SIGXCPU" },
685 { SIGXFSZ, "SIGXFSZ" },
686 #ifdef SIGXRES
687 { SIGXRES, "SIGXRES" },
688 #endif
689 { -1, NULL }
690 };
691
692 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
693 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
694
695 const char* ret = NULL;
696
697 #ifdef SIGRTMIN
698 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
699 if (sig == SIGRTMIN) {
700 ret = "SIGRTMIN";
701 } else if (sig == SIGRTMAX) {
702 ret = "SIGRTMAX";
703 } else {
704 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
705 return out;
706 }
707 }
708 #endif
709
710 if (sig > 0) {
711 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
712 if (g_signal_info[idx].sig == sig) {
713 ret = g_signal_info[idx].name;
714 break;
715 }
716 }
717 }
718
719 if (!ret) {
720 if (!is_valid_signal(sig)) {
721 ret = "INVALID";
722 } else {
723 ret = "UNKNOWN";
724 }
725 }
726
727 if (out && outlen > 0) {
728 strncpy(out, ret, outlen);
729 out[outlen - 1] = '\0';
730 }
731 return out;
732 }
733
734 int os::Posix::get_signal_number(const char* signal_name) {
735 char tmp[30];
736 const char* s = signal_name;
737 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
738 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
739 s = tmp;
740 }
741 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
742 if (strcmp(g_signal_info[idx].name, s) == 0) {
743 return g_signal_info[idx].sig;
744 }
745 }
746 return -1;
747 }
748
749 int os::get_signal_number(const char* signal_name) {
750 return os::Posix::get_signal_number(signal_name);
751 }
752
753 // Returns true if signal number is valid.
754 bool os::Posix::is_valid_signal(int sig) {
755 // MacOS not really POSIX compliant: sigaddset does not return
756 // an error for invalid signal numbers. However, MacOS does not
757 // support real time signals and simply seems to have just 33
758 // signals with no holes in the signal range.
759 #ifdef __APPLE__
760 return sig >= 1 && sig < NSIG;
761 #else
762 // Use sigaddset to check for signal validity.
763 sigset_t set;
764 sigemptyset(&set);
765 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
766 return false;
767 }
768 return true;
769 #endif
770 }
771
772 // Returns:
773 // NULL for an invalid signal number
774 // "SIG<num>" for a valid but unknown signal number
775 // signal name otherwise.
776 const char* os::exception_name(int sig, char* buf, size_t size) {
777 if (!os::Posix::is_valid_signal(sig)) {
778 return NULL;
779 }
780 const char* const name = os::Posix::get_signal_name(sig, buf, size);
781 if (strcmp(name, "UNKNOWN") == 0) {
782 jio_snprintf(buf, size, "SIG%d", sig);
783 }
784 return buf;
785 }
786
787 #define NUM_IMPORTANT_SIGS 32
788 // Returns one-line short description of a signal set in a user provided buffer.
789 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
790 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
791 // Note: for shortness, just print out the first 32. That should
792 // cover most of the useful ones, apart from realtime signals.
793 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
794 const int rc = sigismember(set, sig);
795 if (rc == -1 && errno == EINVAL) {
796 buffer[sig-1] = '?';
797 } else {
798 buffer[sig-1] = rc == 0 ? '0' : '1';
799 }
800 }
801 buffer[NUM_IMPORTANT_SIGS] = 0;
802 return buffer;
803 }
804
805 // Prints one-line description of a signal set.
806 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
807 char buf[NUM_IMPORTANT_SIGS + 1];
808 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
809 st->print("%s", buf);
810 }
811
812 // Writes one-line description of a combination of sigaction.sa_flags into a user
813 // provided buffer. Returns that buffer.
814 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
815 char* p = buffer;
816 size_t remaining = size;
817 bool first = true;
818 int idx = 0;
819
820 assert(buffer, "invalid argument");
821
822 if (size == 0) {
823 return buffer;
824 }
825
826 strncpy(buffer, "none", size);
827
828 const struct {
829 // NB: i is an unsigned int here because SA_RESETHAND is on some
830 // systems 0x80000000, which is implicitly unsigned. Assignining
831 // it to an int field would be an overflow in unsigned-to-signed
832 // conversion.
833 unsigned int i;
834 const char* s;
835 } flaginfo [] = {
836 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
837 { SA_ONSTACK, "SA_ONSTACK" },
838 { SA_RESETHAND, "SA_RESETHAND" },
839 { SA_RESTART, "SA_RESTART" },
840 { SA_SIGINFO, "SA_SIGINFO" },
841 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
842 { SA_NODEFER, "SA_NODEFER" },
843 #ifdef AIX
844 { SA_ONSTACK, "SA_ONSTACK" },
845 { SA_OLDSTYLE, "SA_OLDSTYLE" },
846 #endif
847 { 0, NULL }
848 };
849
850 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
851 if (flags & flaginfo[idx].i) {
852 if (first) {
853 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
854 first = false;
855 } else {
856 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
857 }
858 const size_t len = strlen(p);
859 p += len;
860 remaining -= len;
861 }
862 }
863
864 buffer[size - 1] = '\0';
865
866 return buffer;
867 }
868
869 // Prints one-line description of a combination of sigaction.sa_flags.
870 void os::Posix::print_sa_flags(outputStream* st, int flags) {
871 char buffer[0x100];
872 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
873 st->print("%s", buffer);
874 }
875
876 // Helper function for os::Posix::print_siginfo_...():
877 // return a textual description for signal code.
878 struct enum_sigcode_desc_t {
879 const char* s_name;
880 const char* s_desc;
881 };
882
883 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
884
885 const struct {
886 int sig; int code; const char* s_code; const char* s_desc;
887 } t1 [] = {
888 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
889 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
890 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
891 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
892 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
893 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
894 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
895 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
896 #if defined(IA64) && defined(LINUX)
897 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
898 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
899 #endif
900 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
901 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
902 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
903 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
904 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
905 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
906 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
907 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
908 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
909 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
910 #ifdef AIX
911 // no explanation found what keyerr would be
912 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
913 #endif
914 #if defined(IA64) && !defined(AIX)
915 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
916 #endif
917 #if defined(__sparc) && defined(SOLARIS)
918 // define Solaris Sparc M7 ADI SEGV signals
919 #if !defined(SEGV_ACCADI)
920 #define SEGV_ACCADI 3
921 #endif
922 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
923 #if !defined(SEGV_ACCDERR)
924 #define SEGV_ACCDERR 4
925 #endif
926 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
927 #if !defined(SEGV_ACCPERR)
928 #define SEGV_ACCPERR 5
929 #endif
930 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
931 #endif // defined(__sparc) && defined(SOLARIS)
932 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
933 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
934 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
935 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
936 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
937 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
938 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
939 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
940 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
941 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
942 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
943 #ifdef SIGPOLL
944 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
945 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
946 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
947 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
948 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
949 #endif
950 { -1, -1, NULL, NULL }
951 };
952
953 // Codes valid in any signal context.
954 const struct {
955 int code; const char* s_code; const char* s_desc;
956 } t2 [] = {
957 { SI_USER, "SI_USER", "Signal sent by kill()." },
958 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
959 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
960 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
961 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
962 // Linux specific
963 #ifdef SI_TKILL
964 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
965 #endif
966 #ifdef SI_DETHREAD
967 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
968 #endif
969 #ifdef SI_KERNEL
970 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
971 #endif
972 #ifdef SI_SIGIO
973 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
974 #endif
975
976 #ifdef AIX
977 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
978 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
979 #endif
980
981 #ifdef __sun
982 { SI_NOINFO, "SI_NOINFO", "No signal information" },
983 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
984 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
985 #endif
986
987 { -1, NULL, NULL }
988 };
989
990 const char* s_code = NULL;
991 const char* s_desc = NULL;
992
993 for (int i = 0; t1[i].sig != -1; i ++) {
994 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
995 s_code = t1[i].s_code;
996 s_desc = t1[i].s_desc;
997 break;
998 }
999 }
1000
1001 if (s_code == NULL) {
1002 for (int i = 0; t2[i].s_code != NULL; i ++) {
1003 if (t2[i].code == si->si_code) {
1004 s_code = t2[i].s_code;
1005 s_desc = t2[i].s_desc;
1006 }
1007 }
1008 }
1009
1010 if (s_code == NULL) {
1011 out->s_name = "unknown";
1012 out->s_desc = "unknown";
1013 return false;
1014 }
1015
1016 out->s_name = s_code;
1017 out->s_desc = s_desc;
1018
1019 return true;
1020 }
1021
1022 void os::print_siginfo(outputStream* os, const void* si0) {
1023
1024 const siginfo_t* const si = (const siginfo_t*) si0;
1025
1026 char buf[20];
1027 os->print("siginfo:");
1028
1029 if (!si) {
1030 os->print(" <null>");
1031 return;
1032 }
1033
1034 const int sig = si->si_signo;
1035
1036 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1037
1038 enum_sigcode_desc_t ed;
1039 get_signal_code_description(si, &ed);
1040 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1041
1042 if (si->si_errno) {
1043 os->print(", si_errno: %d", si->si_errno);
1044 }
1045
1046 // Output additional information depending on the signal code.
1047
1048 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1049 // so it depends on the context which member to use. For synchronous error signals,
1050 // we print si_addr, unless the signal was sent by another process or thread, in
1051 // which case we print out pid or tid of the sender.
1052 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1053 const pid_t pid = si->si_pid;
1054 os->print(", si_pid: %ld", (long) pid);
1055 if (IS_VALID_PID(pid)) {
1056 const pid_t me = getpid();
1057 if (me == pid) {
1058 os->print(" (current process)");
1059 }
1060 } else {
1061 os->print(" (invalid)");
1062 }
1063 os->print(", si_uid: %ld", (long) si->si_uid);
1064 if (sig == SIGCHLD) {
1065 os->print(", si_status: %d", si->si_status);
1066 }
1067 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1068 sig == SIGTRAP || sig == SIGFPE) {
1069 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1070 #ifdef SIGPOLL
1071 } else if (sig == SIGPOLL) {
1072 os->print(", si_band: %ld", si->si_band);
1073 #endif
1074 }
1075
1076 }
1077
1078 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1079 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1080 }
1081
1082 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1083 #if defined(AIX)
1084 return Aix::ucontext_get_pc(ctx);
1085 #elif defined(BSD)
1086 return Bsd::ucontext_get_pc(ctx);
1087 #elif defined(LINUX)
1088 return Linux::ucontext_get_pc(ctx);
1089 #elif defined(SOLARIS)
1090 return Solaris::ucontext_get_pc(ctx);
1091 #else
1092 VMError::report_and_die("unimplemented ucontext_get_pc");
1093 #endif
1094 }
1095
1096 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1097 #if defined(AIX)
1098 Aix::ucontext_set_pc(ctx, pc);
1099 #elif defined(BSD)
1100 Bsd::ucontext_set_pc(ctx, pc);
1101 #elif defined(LINUX)
1102 Linux::ucontext_set_pc(ctx, pc);
1103 #elif defined(SOLARIS)
1104 Solaris::ucontext_set_pc(ctx, pc);
1105 #else
1106 VMError::report_and_die("unimplemented ucontext_get_pc");
1107 #endif
1108 }
1109
1110 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1111 size_t stack_size = 0;
1112 size_t guard_size = 0;
1113 int detachstate = 0;
1114 pthread_attr_getstacksize(attr, &stack_size);
1115 pthread_attr_getguardsize(attr, &guard_size);
1116 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1117 LINUX_ONLY(stack_size -= guard_size);
1118 pthread_attr_getdetachstate(attr, &detachstate);
1119 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1120 stack_size / 1024, guard_size / 1024,
1121 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1122 return buf;
1123 }
1124
1125 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1126
1127 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1128 assert(false, "os::Posix::realpath: invalid arguments.");
1129 errno = EINVAL;
1130 return NULL;
1131 }
1132
1133 char* result = NULL;
1134
1135 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1136 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1137 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1138 char* p = ::realpath(filename, NULL);
1139 if (p != NULL) {
1140 if (strlen(p) < outbuflen) {
1141 strcpy(outbuf, p);
1142 result = outbuf;
1143 } else {
1144 errno = ENAMETOOLONG;
1145 }
1146 ::free(p); // *not* os::free
1147 } else {
1148 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1149 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1150 // that it complains about the NULL we handed down as user buffer.
1151 // In this case, use the user provided buffer but at least check whether realpath caused
1152 // a memory overwrite.
1153 if (errno == EINVAL) {
1154 outbuf[outbuflen - 1] = '\0';
1155 p = ::realpath(filename, outbuf);
1156 if (p != NULL) {
1157 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1158 result = p;
1159 }
1160 }
1161 }
1162 return result;
1163
1164 }
1165
1166
1167 // Check minimum allowable stack sizes for thread creation and to initialize
1168 // the java system classes, including StackOverflowError - depends on page
1169 // size.
1170 // The space needed for frames during startup is platform dependent. It
1171 // depends on word size, platform calling conventions, C frame layout and
1172 // interpreter/C1/C2 design decisions. Therefore this is given in a
1173 // platform (os/cpu) dependent constant.
1174 // To this, space for guard mechanisms is added, which depends on the
1175 // page size which again depends on the concrete system the VM is running
1176 // on. Space for libc guard pages is not included in this size.
1177 jint os::Posix::set_minimum_stack_sizes() {
1178 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1179
1180 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1181 JavaThread::stack_guard_zone_size() +
1182 JavaThread::stack_shadow_zone_size();
1183
1184 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1185 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1186
1187 size_t stack_size_in_bytes = ThreadStackSize * K;
1188 if (stack_size_in_bytes != 0 &&
1189 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1190 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1191 // ThreadStackSize so we go with "Java thread stack size" instead
1192 // of "ThreadStackSize" to be more friendly.
1193 tty->print_cr("\nThe Java thread stack size specified is too small. "
1194 "Specify at least " SIZE_FORMAT "k",
1195 _java_thread_min_stack_allowed / K);
1196 return JNI_ERR;
1197 }
1198
1199 // Make the stack size a multiple of the page size so that
1200 // the yellow/red zones can be guarded.
1201 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1202
1203 // Reminder: a compiler thread is a Java thread.
1204 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1205 JavaThread::stack_guard_zone_size() +
1206 JavaThread::stack_shadow_zone_size();
1207
1208 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1209 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1210
1211 stack_size_in_bytes = CompilerThreadStackSize * K;
1212 if (stack_size_in_bytes != 0 &&
1213 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1214 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1215 "Specify at least " SIZE_FORMAT "k",
1216 _compiler_thread_min_stack_allowed / K);
1217 return JNI_ERR;
1218 }
1219
1220 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1221 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1222
1223 stack_size_in_bytes = VMThreadStackSize * K;
1224 if (stack_size_in_bytes != 0 &&
1225 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1226 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1227 "Specify at least " SIZE_FORMAT "k",
1228 _vm_internal_thread_min_stack_allowed / K);
1229 return JNI_ERR;
1230 }
1231 return JNI_OK;
1232 }
1233
1234 // Called when creating the thread. The minimum stack sizes have already been calculated
1235 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1236 size_t stack_size;
1237 if (req_stack_size == 0) {
1238 stack_size = default_stack_size(thr_type);
1239 } else {
1240 stack_size = req_stack_size;
1241 }
1242
1243 switch (thr_type) {
1244 case os::java_thread:
1245 // Java threads use ThreadStackSize which default value can be
1246 // changed with the flag -Xss
1247 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1248 // no requested size and we have a more specific default value
1249 stack_size = JavaThread::stack_size_at_create();
1250 }
1251 stack_size = MAX2(stack_size,
1252 _java_thread_min_stack_allowed);
1253 break;
1254 case os::compiler_thread:
1255 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1256 // no requested size and we have a more specific default value
1257 stack_size = (size_t)(CompilerThreadStackSize * K);
1258 }
1259 stack_size = MAX2(stack_size,
1260 _compiler_thread_min_stack_allowed);
1261 break;
1262 case os::vm_thread:
1263 case os::pgc_thread:
1264 case os::cgc_thread:
1265 case os::watcher_thread:
1266 default: // presume the unknown thr_type is a VM internal
1267 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1268 // no requested size and we have a more specific default value
1269 stack_size = (size_t)(VMThreadStackSize * K);
1270 }
1271
1272 stack_size = MAX2(stack_size,
1273 _vm_internal_thread_min_stack_allowed);
1274 break;
1275 }
1276
1277 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1278 // Be careful not to round up to 0. Align down in that case.
1279 if (stack_size <= SIZE_MAX - vm_page_size()) {
1280 stack_size = align_up(stack_size, vm_page_size());
1281 } else {
1282 stack_size = align_down(stack_size, vm_page_size());
1283 }
1284
1285 return stack_size;
1286 }
1287
1288 os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
1289 assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
1290 }
1291
1292 /*
1293 * See the caveats for this class in os_posix.hpp
1294 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1295 * method and returns false. If none of the signals are raised, returns true.
1296 * The callback is supposed to provide the method that should be protected.
1297 */
1298 bool os::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1299 sigset_t saved_sig_mask;
1300
1301 assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
1302 assert(!WatcherThread::watcher_thread()->has_crash_protection(),
1303 "crash_protection already set?");
1304
1305 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1306 // since on at least some systems (OS X) siglongjmp will restore the mask
1307 // for the process, not the thread
1308 pthread_sigmask(0, NULL, &saved_sig_mask);
1309 if (sigsetjmp(_jmpbuf, 0) == 0) {
1310 // make sure we can see in the signal handler that we have crash protection
1311 // installed
1312 WatcherThread::watcher_thread()->set_crash_protection(this);
1313 cb.call();
1314 // and clear the crash protection
1315 WatcherThread::watcher_thread()->set_crash_protection(NULL);
1316 return true;
1317 }
1318 // this happens when we siglongjmp() back
1319 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1320 WatcherThread::watcher_thread()->set_crash_protection(NULL);
1321 return false;
1322 }
1323
1324 void os::WatcherThreadCrashProtection::restore() {
1325 assert(WatcherThread::watcher_thread()->has_crash_protection(),
1326 "must have crash protection");
1327
1328 siglongjmp(_jmpbuf, 1);
1329 }
1330
1331 void os::WatcherThreadCrashProtection::check_crash_protection(int sig,
1332 Thread* thread) {
1333
1334 if (thread != NULL &&
1335 thread->is_Watcher_thread() &&
1336 WatcherThread::watcher_thread()->has_crash_protection()) {
1337
1338 if (sig == SIGSEGV || sig == SIGBUS) {
1339 WatcherThread::watcher_thread()->crash_protection()->restore();
1340 }
1341 }
1342 }
1343
1344 #define check_with_errno(check_type, cond, msg) \
1345 do { \
1346 int err = errno; \
1347 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
1348 os::errno_name(err)); \
1349 } while (false)
1350
1351 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
1352 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
1353
1354 // POSIX unamed semaphores are not supported on OS X.
1355 #ifndef __APPLE__
1356
1357 PosixSemaphore::PosixSemaphore(uint value) {
1358 int ret = sem_init(&_semaphore, 0, value);
1359
1360 guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
1361 }
1362
1363 PosixSemaphore::~PosixSemaphore() {
1364 sem_destroy(&_semaphore);
1365 }
1366
1367 void PosixSemaphore::signal(uint count) {
1368 for (uint i = 0; i < count; i++) {
1369 int ret = sem_post(&_semaphore);
1370
1371 assert_with_errno(ret == 0, "sem_post failed");
1372 }
1373 }
1374
1375 void PosixSemaphore::wait() {
1376 int ret;
1377
1378 do {
1379 ret = sem_wait(&_semaphore);
1380 } while (ret != 0 && errno == EINTR);
1381
1382 assert_with_errno(ret == 0, "sem_wait failed");
1383 }
1384
1385 bool PosixSemaphore::trywait() {
1386 int ret;
1387
1388 do {
1389 ret = sem_trywait(&_semaphore);
1390 } while (ret != 0 && errno == EINTR);
1391
1392 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
1393
1394 return ret == 0;
1395 }
1396
1397 bool PosixSemaphore::timedwait(struct timespec ts) {
1398 while (true) {
1399 int result = sem_timedwait(&_semaphore, &ts);
1400 if (result == 0) {
1401 return true;
1402 } else if (errno == EINTR) {
1403 continue;
1404 } else if (errno == ETIMEDOUT) {
1405 return false;
1406 } else {
1407 assert_with_errno(false, "timedwait failed");
1408 return false;
1409 }
1410 }
1411 }
1412
1413 #endif // __APPLE__
1414
1415
1416 // Shared pthread_mutex/cond based PlatformEvent implementation.
1417 // Not currently usable by Solaris.
1418
1419 #ifndef SOLARIS
1420
1421 // Shared condattr object for use with relative timed-waits. Will be associated
1422 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1423 // but otherwise whatever default is used by the platform - generally the
1424 // time-of-day clock.
1425 static pthread_condattr_t _condAttr[1];
1426
1427 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1428 // all systems (e.g. FreeBSD) map the default to "normal".
1429 static pthread_mutexattr_t _mutexAttr[1];
1430
1431 // common basic initialization that is always supported
1432 static void pthread_init_common(void) {
1433 int status;
1434 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1435 fatal("pthread_condattr_init: %s", os::strerror(status));
1436 }
1437 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1438 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1439 }
1440 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1441 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1442 }
1443 }
1444
1445 // Not all POSIX types and API's are available on all notionally "posix"
1446 // platforms. If we have build-time support then we will check for actual
1447 // runtime support via dlopen/dlsym lookup. This allows for running on an
1448 // older OS version compared to the build platform. But if there is no
1449 // build time support then there cannot be any runtime support as we do not
1450 // know what the runtime types would be (for example clockid_t might be an
1451 // int or int64_t).
1452 //
1453 #ifdef SUPPORTS_CLOCK_MONOTONIC
1454
1455 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1456
1457 static int (*_clock_gettime)(clockid_t, struct timespec *);
1458 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1459
1460 static bool _use_clock_monotonic_condattr;
1461
1462 // Determine what POSIX API's are present and do appropriate
1463 // configuration.
1464 void os::Posix::init(void) {
1465
1466 // NOTE: no logging available when this is called. Put logging
1467 // statements in init_2().
1468
1469 // Copied from os::Linux::clock_init(). The duplication is temporary.
1470
1471 // 1. Check for CLOCK_MONOTONIC support.
1472
1473 void* handle = NULL;
1474
1475 // For linux we need librt, for other OS we can find
1476 // this function in regular libc.
1477 #ifdef NEEDS_LIBRT
1478 // We do dlopen's in this particular order due to bug in linux
1479 // dynamic loader (see 6348968) leading to crash on exit.
1480 handle = dlopen("librt.so.1", RTLD_LAZY);
1481 if (handle == NULL) {
1482 handle = dlopen("librt.so", RTLD_LAZY);
1483 }
1484 #endif
1485
1486 if (handle == NULL) {
1487 handle = RTLD_DEFAULT;
1488 }
1489
1490 _clock_gettime = NULL;
1491
1492 int (*clock_getres_func)(clockid_t, struct timespec*) =
1493 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1494 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1495 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1496 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1497 // We assume that if both clock_gettime and clock_getres support
1498 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1499 struct timespec res;
1500 struct timespec tp;
1501 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1502 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1503 // Yes, monotonic clock is supported.
1504 _clock_gettime = clock_gettime_func;
1505 } else {
1506 #ifdef NEEDS_LIBRT
1507 // Close librt if there is no monotonic clock.
1508 if (handle != RTLD_DEFAULT) {
1509 dlclose(handle);
1510 }
1511 #endif
1512 }
1513 }
1514
1515 // 2. Check for pthread_condattr_setclock support.
1516
1517 _pthread_condattr_setclock = NULL;
1518
1519 // libpthread is already loaded.
1520 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1521 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1522 "pthread_condattr_setclock");
1523 if (condattr_setclock_func != NULL) {
1524 _pthread_condattr_setclock = condattr_setclock_func;
1525 }
1526
1527 // Now do general initialization.
1528
1529 pthread_init_common();
1530
1531 int status;
1532 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1533 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1534 if (status == EINVAL) {
1535 _use_clock_monotonic_condattr = false;
1536 warning("Unable to use monotonic clock with relative timed-waits" \
1537 " - changes to the time-of-day clock may have adverse affects");
1538 } else {
1539 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1540 }
1541 } else {
1542 _use_clock_monotonic_condattr = true;
1543 }
1544 } else {
1545 _use_clock_monotonic_condattr = false;
1546 }
1547 }
1548
1549 void os::Posix::init_2(void) {
1550 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1551 (_clock_gettime != NULL ? "" : " not"));
1552 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1553 (_pthread_condattr_setclock != NULL ? "" : " not"));
1554 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1555 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1556 }
1557
1558 #else // !SUPPORTS_CLOCK_MONOTONIC
1559
1560 void os::Posix::init(void) {
1561 pthread_init_common();
1562 }
1563
1564 void os::Posix::init_2(void) {
1565 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1566 log_info(os)("Use of pthread_condattr_setclock is not supported");
1567 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1568 }
1569
1570 #endif // SUPPORTS_CLOCK_MONOTONIC
1571
1572 os::PlatformEvent::PlatformEvent() {
1573 int status = pthread_cond_init(_cond, _condAttr);
1574 assert_status(status == 0, status, "cond_init");
1575 status = pthread_mutex_init(_mutex, _mutexAttr);
1576 assert_status(status == 0, status, "mutex_init");
1577 _event = 0;
1578 _nParked = 0;
1579 }
1580
1581 // Utility to convert the given timeout to an absolute timespec
1582 // (based on the appropriate clock) to use with pthread_cond_timewait.
1583 // The clock queried here must be the clock used to manage the
1584 // timeout of the condition variable.
1585 //
1586 // The passed in timeout value is either a relative time in nanoseconds
1587 // or an absolute time in milliseconds. A relative timeout will be
1588 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1589 // the default time-of-day clock will be used.
1590
1591 // Given time is a 64-bit value and the time_t used in the timespec is
1592 // sometimes a signed-32-bit value we have to watch for overflow if times
1593 // way in the future are given. Further on Solaris versions
1594 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1595 // number of seconds, in abstime, is less than current_time + 100000000.
1596 // As it will be over 20 years before "now + 100000000" will overflow we can
1597 // ignore overflow and just impose a hard-limit on seconds using the value
1598 // of "now + 100000000". This places a limit on the timeout of about 3.17
1599 // years from "now".
1600 //
1601 #define MAX_SECS 100000000
1602
1603 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1604 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1605 // on which clock is being used).
1606 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1607 jlong now_part_sec, jlong unit) {
1608 time_t max_secs = now_sec + MAX_SECS;
1609
1610 jlong seconds = timeout / NANOUNITS;
1611 timeout %= NANOUNITS; // remaining nanos
1612
1613 if (seconds >= MAX_SECS) {
1614 // More seconds than we can add, so pin to max_secs.
1615 abstime->tv_sec = max_secs;
1616 abstime->tv_nsec = 0;
1617 } else {
1618 abstime->tv_sec = now_sec + seconds;
1619 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1620 if (nanos >= NANOUNITS) { // overflow
1621 abstime->tv_sec += 1;
1622 nanos -= NANOUNITS;
1623 }
1624 abstime->tv_nsec = nanos;
1625 }
1626 }
1627
1628 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1629 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1630 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1631 time_t max_secs = now_sec + MAX_SECS;
1632
1633 jlong seconds = deadline / MILLIUNITS;
1634 jlong millis = deadline % MILLIUNITS;
1635
1636 if (seconds >= max_secs) {
1637 // Absolute seconds exceeds allowed max, so pin to max_secs.
1638 abstime->tv_sec = max_secs;
1639 abstime->tv_nsec = 0;
1640 } else {
1641 abstime->tv_sec = seconds;
1642 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1643 }
1644 }
1645
1646 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1647 DEBUG_ONLY(int max_secs = MAX_SECS;)
1648
1649 if (timeout < 0) {
1650 timeout = 0;
1651 }
1652
1653 #ifdef SUPPORTS_CLOCK_MONOTONIC
1654
1655 if (_use_clock_monotonic_condattr && !isAbsolute) {
1656 struct timespec now;
1657 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1658 assert_status(status == 0, status, "clock_gettime");
1659 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1660 DEBUG_ONLY(max_secs += now.tv_sec;)
1661 } else {
1662
1663 #else
1664
1665 { // Match the block scope.
1666
1667 #endif // SUPPORTS_CLOCK_MONOTONIC
1668
1669 // Time-of-day clock is all we can reliably use.
1670 struct timeval now;
1671 int status = gettimeofday(&now, NULL);
1672 assert_status(status == 0, errno, "gettimeofday");
1673 if (isAbsolute) {
1674 unpack_abs_time(abstime, timeout, now.tv_sec);
1675 } else {
1676 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1677 }
1678 DEBUG_ONLY(max_secs += now.tv_sec;)
1679 }
1680
1681 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1682 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1683 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1684 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1685 }
1686
1687 // PlatformEvent
1688 //
1689 // Assumption:
1690 // Only one parker can exist on an event, which is why we allocate
1691 // them per-thread. Multiple unparkers can coexist.
1692 //
1693 // _event serves as a restricted-range semaphore.
1694 // -1 : thread is blocked, i.e. there is a waiter
1695 // 0 : neutral: thread is running or ready,
1696 // could have been signaled after a wait started
1697 // 1 : signaled - thread is running or ready
1698 //
1699 // Having three states allows for some detection of bad usage - see
1700 // comments on unpark().
1701
1702 void os::PlatformEvent::park() { // AKA "down()"
1703 // Transitions for _event:
1704 // -1 => -1 : illegal
1705 // 1 => 0 : pass - return immediately
1706 // 0 => -1 : block; then set _event to 0 before returning
1707
1708 // Invariant: Only the thread associated with the PlatformEvent
1709 // may call park().
1710 assert(_nParked == 0, "invariant");
1711
1712 int v;
1713
1714 // atomically decrement _event
1715 for (;;) {
1716 v = _event;
1717 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1718 }
1719 guarantee(v >= 0, "invariant");
1720
1721 if (v == 0) { // Do this the hard way by blocking ...
1722 int status = pthread_mutex_lock(_mutex);
1723 assert_status(status == 0, status, "mutex_lock");
1724 guarantee(_nParked == 0, "invariant");
1725 ++_nParked;
1726 while (_event < 0) {
1727 // OS-level "spurious wakeups" are ignored
1728 status = pthread_cond_wait(_cond, _mutex);
1729 assert_status(status == 0, status, "cond_wait");
1730 }
1731 --_nParked;
1732
1733 _event = 0;
1734 status = pthread_mutex_unlock(_mutex);
1735 assert_status(status == 0, status, "mutex_unlock");
1736 // Paranoia to ensure our locked and lock-free paths interact
1737 // correctly with each other.
1738 OrderAccess::fence();
1739 }
1740 guarantee(_event >= 0, "invariant");
1741 }
1742
1743 int os::PlatformEvent::park(jlong millis) {
1744 // Transitions for _event:
1745 // -1 => -1 : illegal
1746 // 1 => 0 : pass - return immediately
1747 // 0 => -1 : block; then set _event to 0 before returning
1748
1749 // Invariant: Only the thread associated with the Event/PlatformEvent
1750 // may call park().
1751 assert(_nParked == 0, "invariant");
1752
1753 int v;
1754 // atomically decrement _event
1755 for (;;) {
1756 v = _event;
1757 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1758 }
1759 guarantee(v >= 0, "invariant");
1760
1761 if (v == 0) { // Do this the hard way by blocking ...
1762 struct timespec abst;
1763 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1764
1765 int ret = OS_TIMEOUT;
1766 int status = pthread_mutex_lock(_mutex);
1767 assert_status(status == 0, status, "mutex_lock");
1768 guarantee(_nParked == 0, "invariant");
1769 ++_nParked;
1770
1771 while (_event < 0) {
1772 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1773 assert_status(status == 0 || status == ETIMEDOUT,
1774 status, "cond_timedwait");
1775 // OS-level "spurious wakeups" are ignored unless the archaic
1776 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1777 if (!FilterSpuriousWakeups) break;
1778 if (status == ETIMEDOUT) break;
1779 }
1780 --_nParked;
1781
1782 if (_event >= 0) {
1783 ret = OS_OK;
1784 }
1785
1786 _event = 0;
1787 status = pthread_mutex_unlock(_mutex);
1788 assert_status(status == 0, status, "mutex_unlock");
1789 // Paranoia to ensure our locked and lock-free paths interact
1790 // correctly with each other.
1791 OrderAccess::fence();
1792 return ret;
1793 }
1794 return OS_OK;
1795 }
1796
1797 void os::PlatformEvent::unpark() {
1798 // Transitions for _event:
1799 // 0 => 1 : just return
1800 // 1 => 1 : just return
1801 // -1 => either 0 or 1; must signal target thread
1802 // That is, we can safely transition _event from -1 to either
1803 // 0 or 1.
1804 // See also: "Semaphores in Plan 9" by Mullender & Cox
1805 //
1806 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1807 // that it will take two back-to-back park() calls for the owning
1808 // thread to block. This has the benefit of forcing a spurious return
1809 // from the first park() call after an unpark() call which will help
1810 // shake out uses of park() and unpark() without checking state conditions
1811 // properly. This spurious return doesn't manifest itself in any user code
1812 // but only in the correctly written condition checking loops of ObjectMonitor,
1813 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1814
1815 if (Atomic::xchg(1, &_event) >= 0) return;
1816
1817 int status = pthread_mutex_lock(_mutex);
1818 assert_status(status == 0, status, "mutex_lock");
1819 int anyWaiters = _nParked;
1820 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1821 status = pthread_mutex_unlock(_mutex);
1822 assert_status(status == 0, status, "mutex_unlock");
1823
1824 // Note that we signal() *after* dropping the lock for "immortal" Events.
1825 // This is safe and avoids a common class of futile wakeups. In rare
1826 // circumstances this can cause a thread to return prematurely from
1827 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1828 // will simply re-test the condition and re-park itself.
1829 // This provides particular benefit if the underlying platform does not
1830 // provide wait morphing.
1831
1832 if (anyWaiters != 0) {
1833 status = pthread_cond_signal(_cond);
1834 assert_status(status == 0, status, "cond_signal");
1835 }
1836 }
1837
1838 // JSR166 support
1839
1840 os::PlatformParker::PlatformParker() {
1841 int status;
1842 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1843 assert_status(status == 0, status, "cond_init rel");
1844 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
1845 assert_status(status == 0, status, "cond_init abs");
1846 status = pthread_mutex_init(_mutex, _mutexAttr);
1847 assert_status(status == 0, status, "mutex_init");
1848 _cur_index = -1; // mark as unused
1849 }
1850
1851 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
1852 // sets count to 1 and signals condvar. Only one thread ever waits
1853 // on the condvar. Contention seen when trying to park implies that someone
1854 // is unparking you, so don't wait. And spurious returns are fine, so there
1855 // is no need to track notifications.
1856
1857 void Parker::park(bool isAbsolute, jlong time) {
1858
1859 // Optional fast-path check:
1860 // Return immediately if a permit is available.
1861 // We depend on Atomic::xchg() having full barrier semantics
1862 // since we are doing a lock-free update to _counter.
1863 if (Atomic::xchg(0, &_counter) > 0) return;
1864
1865 Thread* thread = Thread::current();
1866 assert(thread->is_Java_thread(), "Must be JavaThread");
1867 JavaThread *jt = (JavaThread *)thread;
1868
1869 // Optional optimization -- avoid state transitions if there's
1870 // an interrupt pending.
1871 if (Thread::is_interrupted(thread, false)) {
1872 return;
1873 }
1874
1875 // Next, demultiplex/decode time arguments
1876 struct timespec absTime;
1877 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
1878 return;
1879 }
1880 if (time > 0) {
1881 to_abstime(&absTime, time, isAbsolute);
1882 }
1883
1884 // Enter safepoint region
1885 // Beware of deadlocks such as 6317397.
1886 // The per-thread Parker:: mutex is a classic leaf-lock.
1887 // In particular a thread must never block on the Threads_lock while
1888 // holding the Parker:: mutex. If safepoints are pending both the
1889 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
1890 ThreadBlockInVM tbivm(jt);
1891
1892 // Don't wait if cannot get lock since interference arises from
1893 // unparking. Also re-check interrupt before trying wait.
1894 if (Thread::is_interrupted(thread, false) ||
1895 pthread_mutex_trylock(_mutex) != 0) {
1896 return;
1897 }
1898
1899 int status;
1900 if (_counter > 0) { // no wait needed
1901 _counter = 0;
1902 status = pthread_mutex_unlock(_mutex);
1903 assert_status(status == 0, status, "invariant");
1904 // Paranoia to ensure our locked and lock-free paths interact
1905 // correctly with each other and Java-level accesses.
1906 OrderAccess::fence();
1907 return;
1908 }
1909
1910 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
1911 jt->set_suspend_equivalent();
1912 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1913
1914 assert(_cur_index == -1, "invariant");
1915 if (time == 0) {
1916 _cur_index = REL_INDEX; // arbitrary choice when not timed
1917 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
1918 assert_status(status == 0, status, "cond_timedwait");
1919 }
1920 else {
1921 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
1922 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
1923 assert_status(status == 0 || status == ETIMEDOUT,
1924 status, "cond_timedwait");
1925 }
1926 _cur_index = -1;
1927
1928 _counter = 0;
1929 status = pthread_mutex_unlock(_mutex);
1930 assert_status(status == 0, status, "invariant");
1931 // Paranoia to ensure our locked and lock-free paths interact
1932 // correctly with each other and Java-level accesses.
1933 OrderAccess::fence();
1934
1935 // If externally suspended while waiting, re-suspend
1936 if (jt->handle_special_suspend_equivalent_condition()) {
1937 jt->java_suspend_self();
1938 }
1939 }
1940
1941 void Parker::unpark() {
1942 int status = pthread_mutex_lock(_mutex);
1943 assert_status(status == 0, status, "invariant");
1944 const int s = _counter;
1945 _counter = 1;
1946 // must capture correct index before unlocking
1947 int index = _cur_index;
1948 status = pthread_mutex_unlock(_mutex);
1949 assert_status(status == 0, status, "invariant");
1950
1951 // Note that we signal() *after* dropping the lock for "immortal" Events.
1952 // This is safe and avoids a common class of futile wakeups. In rare
1953 // circumstances this can cause a thread to return prematurely from
1954 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1955 // will simply re-test the condition and re-park itself.
1956 // This provides particular benefit if the underlying platform does not
1957 // provide wait morphing.
1958
1959 if (s < 1 && index != -1) {
1960 // thread is definitely parked
1961 status = pthread_cond_signal(&_cond[index]);
1962 assert_status(status == 0, status, "invariant");
1963 }
1964 }
1965
1966
1967 #endif // !SOLARIS