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 " 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);
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 = align_up(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(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
212
213 st->print(", CORE ");
214 getrlimit(RLIMIT_CORE, &rlim);
215 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
216 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
217
218 // Isn't there on solaris
219 #if defined(AIX)
220 st->print(", NPROC ");
221 st->print("%d", sysconf(_SC_CHILD_MAX));
222 #elif !defined(SOLARIS)
223 st->print(", NPROC ");
224 getrlimit(RLIMIT_NPROC, &rlim);
225 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
226 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
227 #endif
228
229 st->print(", NOFILE ");
230 getrlimit(RLIMIT_NOFILE, &rlim);
231 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
232 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
233
234 st->print(", AS ");
235 getrlimit(RLIMIT_AS, &rlim);
236 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
237 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
238
239 st->print(", DATA ");
240 getrlimit(RLIMIT_DATA, &rlim);
241 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
242 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
243
244 st->print(", FSIZE ");
245 getrlimit(RLIMIT_FSIZE, &rlim);
246 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
247 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
248
249 st->cr();
250 }
251
252 void os::Posix::print_uname_info(outputStream* st) {
253 // kernel
254 st->print("uname:");
255 struct utsname name;
256 uname(&name);
257 st->print("%s ", name.sysname);
258 #ifdef ASSERT
259 st->print("%s ", name.nodename);
260 #endif
261 st->print("%s ", name.release);
262 st->print("%s ", name.version);
263 st->print("%s", name.machine);
264 st->cr();
265 }
266
267 bool os::get_host_name(char* buf, size_t buflen) {
268 struct utsname name;
269 uname(&name);
270 jio_snprintf(buf, buflen, "%s", name.nodename);
271 return true;
272 }
273
274 bool os::has_allocatable_memory_limit(julong* limit) {
275 struct rlimit rlim;
276 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
277 // if there was an error when calling getrlimit, assume that there is no limitation
278 // on virtual memory.
279 bool result;
280 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
281 result = false;
282 } else {
283 *limit = (julong)rlim.rlim_cur;
284 result = true;
285 }
286 #ifdef _LP64
287 return result;
288 #else
289 // arbitrary virtual space limit for 32 bit Unices found by testing. If
290 // getrlimit above returned a limit, bound it with this limit. Otherwise
291 // directly use it.
292 const julong max_virtual_limit = (julong)3800*M;
293 if (result) {
294 *limit = MIN2(*limit, max_virtual_limit);
295 } else {
296 *limit = max_virtual_limit;
297 }
298
299 // bound by actually allocatable memory. The algorithm uses two bounds, an
300 // upper and a lower limit. The upper limit is the current highest amount of
301 // memory that could not be allocated, the lower limit is the current highest
302 // amount of memory that could be allocated.
303 // The algorithm iteratively refines the result by halving the difference
304 // between these limits, updating either the upper limit (if that value could
305 // not be allocated) or the lower limit (if the that value could be allocated)
306 // until the difference between these limits is "small".
307
308 // the minimum amount of memory we care about allocating.
309 const julong min_allocation_size = M;
310
311 julong upper_limit = *limit;
312
313 // first check a few trivial cases
314 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
315 *limit = upper_limit;
316 } else if (!is_allocatable(min_allocation_size)) {
317 // we found that not even min_allocation_size is allocatable. Return it
318 // anyway. There is no point to search for a better value any more.
319 *limit = min_allocation_size;
320 } else {
321 // perform the binary search.
322 julong lower_limit = min_allocation_size;
323 while ((upper_limit - lower_limit) > min_allocation_size) {
324 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
325 temp_limit = align_down(temp_limit, min_allocation_size);
326 if (is_allocatable(temp_limit)) {
327 lower_limit = temp_limit;
328 } else {
329 upper_limit = temp_limit;
330 }
331 }
332 *limit = lower_limit;
333 }
334 return true;
335 #endif
336 }
337
338 const char* os::get_current_directory(char *buf, size_t buflen) {
339 return getcwd(buf, buflen);
340 }
341
342 FILE* os::open(int fd, const char* mode) {
343 return ::fdopen(fd, mode);
344 }
345
346 void os::flockfile(FILE* fp) {
347 ::flockfile(fp);
348 }
349
350 void os::funlockfile(FILE* fp) {
351 ::funlockfile(fp);
352 }
353
354 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
355 // which is used to find statically linked in agents.
356 // Parameters:
357 // sym_name: Symbol in library we are looking for
358 // lib_name: Name of library to look in, NULL for shared libs.
359 // is_absolute_path == true if lib_name is absolute path to agent
360 // such as "/a/b/libL.so"
361 // == false if only the base name of the library is passed in
362 // such as "L"
363 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
364 bool is_absolute_path) {
365 char *agent_entry_name;
366 size_t len;
367 size_t name_len;
368 size_t prefix_len = strlen(JNI_LIB_PREFIX);
369 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
370 const char *start;
371
372 if (lib_name != NULL) {
373 name_len = strlen(lib_name);
374 if (is_absolute_path) {
375 // Need to strip path, prefix and suffix
376 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
377 lib_name = ++start;
378 }
379 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
380 return NULL;
381 }
382 lib_name += prefix_len;
383 name_len = strlen(lib_name) - suffix_len;
384 }
385 }
386 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
387 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
388 if (agent_entry_name == NULL) {
389 return NULL;
390 }
391 strcpy(agent_entry_name, sym_name);
392 if (lib_name != NULL) {
393 strcat(agent_entry_name, "_");
394 strncat(agent_entry_name, lib_name, name_len);
395 }
396 return agent_entry_name;
397 }
398
399 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
400 assert(thread == Thread::current(), "thread consistency check");
401
402 ParkEvent * const slp = thread->_SleepEvent ;
403 slp->reset() ;
404 OrderAccess::fence() ;
405
406 if (interruptible) {
407 jlong prevtime = javaTimeNanos();
408
409 for (;;) {
410 if (os::is_interrupted(thread, true)) {
411 return OS_INTRPT;
412 }
413
414 jlong newtime = javaTimeNanos();
415
416 if (newtime - prevtime < 0) {
417 // time moving backwards, should only happen if no monotonic clock
418 // not a guarantee() because JVM should not abort on kernel/glibc bugs
419 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
420 } else {
421 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
422 }
423
424 if (millis <= 0) {
425 return OS_OK;
426 }
427
428 prevtime = newtime;
429
430 {
431 assert(thread->is_Java_thread(), "sanity check");
432 JavaThread *jt = (JavaThread *) thread;
433 ThreadBlockInVM tbivm(jt);
434 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
435
436 jt->set_suspend_equivalent();
437 // cleared by handle_special_suspend_equivalent_condition() or
438 // java_suspend_self() via check_and_wait_while_suspended()
439
440 slp->park(millis);
441
442 // were we externally suspended while we were waiting?
443 jt->check_and_wait_while_suspended();
444 }
445 }
446 } else {
447 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
448 jlong prevtime = javaTimeNanos();
449
450 for (;;) {
451 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
452 // the 1st iteration ...
453 jlong newtime = javaTimeNanos();
454
455 if (newtime - prevtime < 0) {
456 // time moving backwards, should only happen if no monotonic clock
457 // not a guarantee() because JVM should not abort on kernel/glibc bugs
458 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
459 } else {
460 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
461 }
462
463 if (millis <= 0) break ;
464
465 prevtime = newtime;
466 slp->park(millis);
467 }
468 return OS_OK ;
469 }
470 }
471
472 ////////////////////////////////////////////////////////////////////////////////
473 // interrupt support
474
475 void os::interrupt(Thread* thread) {
476 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
477 "possibility of dangling Thread pointer");
478
479 OSThread* osthread = thread->osthread();
480
481 if (!osthread->interrupted()) {
482 osthread->set_interrupted(true);
483 // More than one thread can get here with the same value of osthread,
484 // resulting in multiple notifications. We do, however, want the store
485 // to interrupted() to be visible to other threads before we execute unpark().
486 OrderAccess::fence();
487 ParkEvent * const slp = thread->_SleepEvent ;
488 if (slp != NULL) slp->unpark() ;
489 }
490
491 // For JSR166. Unpark even if interrupt status already was set
492 if (thread->is_Java_thread())
493 ((JavaThread*)thread)->parker()->unpark();
494
495 ParkEvent * ev = thread->_ParkEvent ;
496 if (ev != NULL) ev->unpark() ;
497
498 }
499
500 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
501 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
502 "possibility of dangling Thread pointer");
503
504 OSThread* osthread = thread->osthread();
505
506 bool interrupted = osthread->interrupted();
507
508 // NOTE that since there is no "lock" around the interrupt and
509 // is_interrupted operations, there is the possibility that the
510 // interrupted flag (in osThread) will be "false" but that the
511 // low-level events will be in the signaled state. This is
512 // intentional. The effect of this is that Object.wait() and
513 // LockSupport.park() will appear to have a spurious wakeup, which
514 // is allowed and not harmful, and the possibility is so rare that
515 // it is not worth the added complexity to add yet another lock.
516 // For the sleep event an explicit reset is performed on entry
517 // to os::sleep, so there is no early return. It has also been
518 // recommended not to put the interrupted flag into the "event"
519 // structure because it hides the issue.
520 if (interrupted && clear_interrupted) {
521 osthread->set_interrupted(false);
522 // consider thread->_SleepEvent->reset() ... optional optimization
523 }
524
525 return interrupted;
526 }
527
528
529
530 static const struct {
531 int sig; const char* name;
532 }
533 g_signal_info[] =
534 {
535 { SIGABRT, "SIGABRT" },
536 #ifdef SIGAIO
537 { SIGAIO, "SIGAIO" },
538 #endif
539 { SIGALRM, "SIGALRM" },
540 #ifdef SIGALRM1
541 { SIGALRM1, "SIGALRM1" },
542 #endif
543 { SIGBUS, "SIGBUS" },
544 #ifdef SIGCANCEL
545 { SIGCANCEL, "SIGCANCEL" },
546 #endif
547 { SIGCHLD, "SIGCHLD" },
548 #ifdef SIGCLD
549 { SIGCLD, "SIGCLD" },
550 #endif
551 { SIGCONT, "SIGCONT" },
552 #ifdef SIGCPUFAIL
553 { SIGCPUFAIL, "SIGCPUFAIL" },
554 #endif
555 #ifdef SIGDANGER
556 { SIGDANGER, "SIGDANGER" },
557 #endif
558 #ifdef SIGDIL
559 { SIGDIL, "SIGDIL" },
560 #endif
561 #ifdef SIGEMT
562 { SIGEMT, "SIGEMT" },
563 #endif
564 { SIGFPE, "SIGFPE" },
565 #ifdef SIGFREEZE
566 { SIGFREEZE, "SIGFREEZE" },
567 #endif
568 #ifdef SIGGFAULT
569 { SIGGFAULT, "SIGGFAULT" },
570 #endif
571 #ifdef SIGGRANT
572 { SIGGRANT, "SIGGRANT" },
573 #endif
574 { SIGHUP, "SIGHUP" },
575 { SIGILL, "SIGILL" },
576 { SIGINT, "SIGINT" },
577 #ifdef SIGIO
578 { SIGIO, "SIGIO" },
579 #endif
580 #ifdef SIGIOINT
581 { SIGIOINT, "SIGIOINT" },
582 #endif
583 #ifdef SIGIOT
584 // SIGIOT is there for BSD compatibility, but on most Unices just a
585 // synonym for SIGABRT. The result should be "SIGABRT", not
586 // "SIGIOT".
587 #if (SIGIOT != SIGABRT )
588 { SIGIOT, "SIGIOT" },
589 #endif
590 #endif
591 #ifdef SIGKAP
592 { SIGKAP, "SIGKAP" },
593 #endif
594 { SIGKILL, "SIGKILL" },
595 #ifdef SIGLOST
596 { SIGLOST, "SIGLOST" },
597 #endif
598 #ifdef SIGLWP
599 { SIGLWP, "SIGLWP" },
600 #endif
601 #ifdef SIGLWPTIMER
602 { SIGLWPTIMER, "SIGLWPTIMER" },
603 #endif
604 #ifdef SIGMIGRATE
605 { SIGMIGRATE, "SIGMIGRATE" },
606 #endif
607 #ifdef SIGMSG
608 { SIGMSG, "SIGMSG" },
609 #endif
610 { SIGPIPE, "SIGPIPE" },
611 #ifdef SIGPOLL
612 { SIGPOLL, "SIGPOLL" },
613 #endif
614 #ifdef SIGPRE
615 { SIGPRE, "SIGPRE" },
616 #endif
617 { SIGPROF, "SIGPROF" },
618 #ifdef SIGPTY
619 { SIGPTY, "SIGPTY" },
620 #endif
621 #ifdef SIGPWR
622 { SIGPWR, "SIGPWR" },
623 #endif
624 { SIGQUIT, "SIGQUIT" },
625 #ifdef SIGRECONFIG
626 { SIGRECONFIG, "SIGRECONFIG" },
627 #endif
628 #ifdef SIGRECOVERY
629 { SIGRECOVERY, "SIGRECOVERY" },
630 #endif
631 #ifdef SIGRESERVE
632 { SIGRESERVE, "SIGRESERVE" },
633 #endif
634 #ifdef SIGRETRACT
635 { SIGRETRACT, "SIGRETRACT" },
636 #endif
637 #ifdef SIGSAK
638 { SIGSAK, "SIGSAK" },
639 #endif
640 { SIGSEGV, "SIGSEGV" },
641 #ifdef SIGSOUND
642 { SIGSOUND, "SIGSOUND" },
643 #endif
644 #ifdef SIGSTKFLT
645 { SIGSTKFLT, "SIGSTKFLT" },
646 #endif
647 { SIGSTOP, "SIGSTOP" },
648 { SIGSYS, "SIGSYS" },
649 #ifdef SIGSYSERROR
650 { SIGSYSERROR, "SIGSYSERROR" },
651 #endif
652 #ifdef SIGTALRM
653 { SIGTALRM, "SIGTALRM" },
654 #endif
655 { SIGTERM, "SIGTERM" },
656 #ifdef SIGTHAW
657 { SIGTHAW, "SIGTHAW" },
658 #endif
659 { SIGTRAP, "SIGTRAP" },
660 #ifdef SIGTSTP
661 { SIGTSTP, "SIGTSTP" },
662 #endif
663 { SIGTTIN, "SIGTTIN" },
664 { SIGTTOU, "SIGTTOU" },
665 #ifdef SIGURG
666 { SIGURG, "SIGURG" },
667 #endif
668 { SIGUSR1, "SIGUSR1" },
669 { SIGUSR2, "SIGUSR2" },
670 #ifdef SIGVIRT
671 { SIGVIRT, "SIGVIRT" },
672 #endif
673 { SIGVTALRM, "SIGVTALRM" },
674 #ifdef SIGWAITING
675 { SIGWAITING, "SIGWAITING" },
676 #endif
677 #ifdef SIGWINCH
678 { SIGWINCH, "SIGWINCH" },
679 #endif
680 #ifdef SIGWINDOW
681 { SIGWINDOW, "SIGWINDOW" },
682 #endif
683 { SIGXCPU, "SIGXCPU" },
684 { SIGXFSZ, "SIGXFSZ" },
685 #ifdef SIGXRES
686 { SIGXRES, "SIGXRES" },
687 #endif
688 { -1, NULL }
689 };
690
691 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
692 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
693
694 const char* ret = NULL;
695
696 #ifdef SIGRTMIN
697 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
698 if (sig == SIGRTMIN) {
699 ret = "SIGRTMIN";
700 } else if (sig == SIGRTMAX) {
701 ret = "SIGRTMAX";
702 } else {
703 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
704 return out;
705 }
706 }
707 #endif
708
709 if (sig > 0) {
710 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
711 if (g_signal_info[idx].sig == sig) {
712 ret = g_signal_info[idx].name;
713 break;
714 }
715 }
716 }
717
718 if (!ret) {
719 if (!is_valid_signal(sig)) {
720 ret = "INVALID";
721 } else {
722 ret = "UNKNOWN";
723 }
724 }
725
726 if (out && outlen > 0) {
727 strncpy(out, ret, outlen);
728 out[outlen - 1] = '\0';
729 }
730 return out;
731 }
732
733 int os::Posix::get_signal_number(const char* signal_name) {
734 char tmp[30];
735 const char* s = signal_name;
736 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
737 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
738 s = tmp;
739 }
740 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
741 if (strcmp(g_signal_info[idx].name, s) == 0) {
742 return g_signal_info[idx].sig;
743 }
744 }
745 return -1;
746 }
747
748 int os::get_signal_number(const char* signal_name) {
749 return os::Posix::get_signal_number(signal_name);
750 }
751
752 // Returns true if signal number is valid.
753 bool os::Posix::is_valid_signal(int sig) {
754 // MacOS not really POSIX compliant: sigaddset does not return
755 // an error for invalid signal numbers. However, MacOS does not
756 // support real time signals and simply seems to have just 33
757 // signals with no holes in the signal range.
758 #ifdef __APPLE__
759 return sig >= 1 && sig < NSIG;
760 #else
761 // Use sigaddset to check for signal validity.
762 sigset_t set;
763 sigemptyset(&set);
764 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
765 return false;
766 }
767 return true;
768 #endif
769 }
770
771 // Returns:
772 // NULL for an invalid signal number
773 // "SIG<num>" for a valid but unknown signal number
774 // signal name otherwise.
775 const char* os::exception_name(int sig, char* buf, size_t size) {
776 if (!os::Posix::is_valid_signal(sig)) {
777 return NULL;
778 }
779 const char* const name = os::Posix::get_signal_name(sig, buf, size);
780 if (strcmp(name, "UNKNOWN") == 0) {
781 jio_snprintf(buf, size, "SIG%d", sig);
782 }
783 return buf;
784 }
785
786 #define NUM_IMPORTANT_SIGS 32
787 // Returns one-line short description of a signal set in a user provided buffer.
788 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
789 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
790 // Note: for shortness, just print out the first 32. That should
791 // cover most of the useful ones, apart from realtime signals.
792 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
793 const int rc = sigismember(set, sig);
794 if (rc == -1 && errno == EINVAL) {
795 buffer[sig-1] = '?';
796 } else {
797 buffer[sig-1] = rc == 0 ? '0' : '1';
798 }
799 }
800 buffer[NUM_IMPORTANT_SIGS] = 0;
801 return buffer;
802 }
803
804 // Prints one-line description of a signal set.
805 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
806 char buf[NUM_IMPORTANT_SIGS + 1];
807 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
808 st->print("%s", buf);
809 }
810
811 // Writes one-line description of a combination of sigaction.sa_flags into a user
812 // provided buffer. Returns that buffer.
813 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
814 char* p = buffer;
815 size_t remaining = size;
816 bool first = true;
817 int idx = 0;
818
819 assert(buffer, "invalid argument");
820
821 if (size == 0) {
822 return buffer;
823 }
824
825 strncpy(buffer, "none", size);
826
827 const struct {
828 // NB: i is an unsigned int here because SA_RESETHAND is on some
829 // systems 0x80000000, which is implicitly unsigned. Assignining
830 // it to an int field would be an overflow in unsigned-to-signed
831 // conversion.
832 unsigned int i;
833 const char* s;
834 } flaginfo [] = {
835 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
836 { SA_ONSTACK, "SA_ONSTACK" },
837 { SA_RESETHAND, "SA_RESETHAND" },
838 { SA_RESTART, "SA_RESTART" },
839 { SA_SIGINFO, "SA_SIGINFO" },
840 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
841 { SA_NODEFER, "SA_NODEFER" },
842 #ifdef AIX
843 { SA_ONSTACK, "SA_ONSTACK" },
844 { SA_OLDSTYLE, "SA_OLDSTYLE" },
845 #endif
846 { 0, NULL }
847 };
848
849 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
850 if (flags & flaginfo[idx].i) {
851 if (first) {
852 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
853 first = false;
854 } else {
855 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
856 }
857 const size_t len = strlen(p);
858 p += len;
859 remaining -= len;
860 }
861 }
862
863 buffer[size - 1] = '\0';
864
865 return buffer;
866 }
867
868 // Prints one-line description of a combination of sigaction.sa_flags.
869 void os::Posix::print_sa_flags(outputStream* st, int flags) {
870 char buffer[0x100];
871 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
872 st->print("%s", buffer);
873 }
874
875 // Helper function for os::Posix::print_siginfo_...():
876 // return a textual description for signal code.
877 struct enum_sigcode_desc_t {
878 const char* s_name;
879 const char* s_desc;
880 };
881
882 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
883
884 const struct {
885 int sig; int code; const char* s_code; const char* s_desc;
886 } t1 [] = {
887 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
888 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
889 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
890 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
891 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
892 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
893 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
894 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
895 #if defined(IA64) && defined(LINUX)
896 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
897 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
898 #endif
899 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
900 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
901 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
902 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
903 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
904 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
905 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
906 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
907 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
908 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
909 #ifdef AIX
910 // no explanation found what keyerr would be
911 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
912 #endif
913 #if defined(IA64) && !defined(AIX)
914 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
915 #endif
916 #if defined(__sparc) && defined(SOLARIS)
917 // define Solaris Sparc M7 ADI SEGV signals
918 #if !defined(SEGV_ACCADI)
919 #define SEGV_ACCADI 3
920 #endif
921 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
922 #if !defined(SEGV_ACCDERR)
923 #define SEGV_ACCDERR 4
924 #endif
925 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
926 #if !defined(SEGV_ACCPERR)
927 #define SEGV_ACCPERR 5
928 #endif
929 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
930 #endif // defined(__sparc) && defined(SOLARIS)
931 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
932 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
933 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
934 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
935 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
936 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
937 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
938 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
939 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
940 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
941 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
942 #ifdef SIGPOLL
943 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
944 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
945 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
946 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
947 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
948 #endif
949 { -1, -1, NULL, NULL }
950 };
951
952 // Codes valid in any signal context.
953 const struct {
954 int code; const char* s_code; const char* s_desc;
955 } t2 [] = {
956 { SI_USER, "SI_USER", "Signal sent by kill()." },
957 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
958 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
959 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
960 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
961 // Linux specific
962 #ifdef SI_TKILL
963 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
964 #endif
965 #ifdef SI_DETHREAD
966 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
967 #endif
968 #ifdef SI_KERNEL
969 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
970 #endif
971 #ifdef SI_SIGIO
972 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
973 #endif
974
975 #ifdef AIX
976 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
977 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
978 #endif
979
980 #ifdef __sun
981 { SI_NOINFO, "SI_NOINFO", "No signal information" },
982 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
983 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
984 #endif
985
986 { -1, NULL, NULL }
987 };
988
989 const char* s_code = NULL;
990 const char* s_desc = NULL;
991
992 for (int i = 0; t1[i].sig != -1; i ++) {
993 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
994 s_code = t1[i].s_code;
995 s_desc = t1[i].s_desc;
996 break;
997 }
998 }
999
1000 if (s_code == NULL) {
1001 for (int i = 0; t2[i].s_code != NULL; i ++) {
1002 if (t2[i].code == si->si_code) {
1003 s_code = t2[i].s_code;
1004 s_desc = t2[i].s_desc;
1005 }
1006 }
1007 }
1008
1009 if (s_code == NULL) {
1010 out->s_name = "unknown";
1011 out->s_desc = "unknown";
1012 return false;
1013 }
1014
1015 out->s_name = s_code;
1016 out->s_desc = s_desc;
1017
1018 return true;
1019 }
1020
1021 void os::print_siginfo(outputStream* os, const void* si0) {
1022
1023 const siginfo_t* const si = (const siginfo_t*) si0;
1024
1025 char buf[20];
1026 os->print("siginfo:");
1027
1028 if (!si) {
1029 os->print(" <null>");
1030 return;
1031 }
1032
1033 const int sig = si->si_signo;
1034
1035 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1036
1037 enum_sigcode_desc_t ed;
1038 get_signal_code_description(si, &ed);
1039 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1040
1041 if (si->si_errno) {
1042 os->print(", si_errno: %d", si->si_errno);
1043 }
1044
1045 // Output additional information depending on the signal code.
1046
1047 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1048 // so it depends on the context which member to use. For synchronous error signals,
1049 // we print si_addr, unless the signal was sent by another process or thread, in
1050 // which case we print out pid or tid of the sender.
1051 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1052 const pid_t pid = si->si_pid;
1053 os->print(", si_pid: %ld", (long) pid);
1054 if (IS_VALID_PID(pid)) {
1055 const pid_t me = getpid();
1056 if (me == pid) {
1057 os->print(" (current process)");
1058 }
1059 } else {
1060 os->print(" (invalid)");
1061 }
1062 os->print(", si_uid: %ld", (long) si->si_uid);
1063 if (sig == SIGCHLD) {
1064 os->print(", si_status: %d", si->si_status);
1065 }
1066 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1067 sig == SIGTRAP || sig == SIGFPE) {
1068 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1069 #ifdef SIGPOLL
1070 } else if (sig == SIGPOLL) {
1071 os->print(", si_band: %ld", si->si_band);
1072 #endif
1073 }
1074
1075 }
1076
1077 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1078 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1079 }
1080
1081 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1082 #if defined(AIX)
1083 return Aix::ucontext_get_pc(ctx);
1084 #elif defined(BSD)
1085 return Bsd::ucontext_get_pc(ctx);
1086 #elif defined(LINUX)
1087 return Linux::ucontext_get_pc(ctx);
1088 #elif defined(SOLARIS)
1089 return Solaris::ucontext_get_pc(ctx);
1090 #else
1091 VMError::report_and_die("unimplemented ucontext_get_pc");
1092 #endif
1093 }
1094
1095 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1096 #if defined(AIX)
1097 Aix::ucontext_set_pc(ctx, pc);
1098 #elif defined(BSD)
1099 Bsd::ucontext_set_pc(ctx, pc);
1100 #elif defined(LINUX)
1101 Linux::ucontext_set_pc(ctx, pc);
1102 #elif defined(SOLARIS)
1103 Solaris::ucontext_set_pc(ctx, pc);
1104 #else
1105 VMError::report_and_die("unimplemented ucontext_get_pc");
1106 #endif
1107 }
1108
1109 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1110 size_t stack_size = 0;
1111 size_t guard_size = 0;
1112 int detachstate = 0;
1113 pthread_attr_getstacksize(attr, &stack_size);
1114 pthread_attr_getguardsize(attr, &guard_size);
1115 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1116 LINUX_ONLY(stack_size -= guard_size);
1117 pthread_attr_getdetachstate(attr, &detachstate);
1118 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1119 stack_size / 1024, guard_size / 1024,
1120 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1121 return buf;
1122 }
1123
1124 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1125
1126 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1127 assert(false, "os::Posix::realpath: invalid arguments.");
1128 errno = EINVAL;
1129 return NULL;
1130 }
1131
1132 char* result = NULL;
1133
1134 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1135 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1136 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1137 char* p = ::realpath(filename, NULL);
1138 if (p != NULL) {
1139 if (strlen(p) < outbuflen) {
1140 strcpy(outbuf, p);
1141 result = outbuf;
1142 } else {
1143 errno = ENAMETOOLONG;
1144 }
1145 ::free(p); // *not* os::free
1146 } else {
1147 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1148 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1149 // that it complains about the NULL we handed down as user buffer.
1150 // In this case, use the user provided buffer but at least check whether realpath caused
1151 // a memory overwrite.
1152 if (errno == EINVAL) {
1153 outbuf[outbuflen - 1] = '\0';
1154 p = ::realpath(filename, outbuf);
1155 if (p != NULL) {
1156 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1157 result = p;
1158 }
1159 }
1160 }
1161 return result;
1162
1163 }
1164
1165
1166 // Check minimum allowable stack sizes for thread creation and to initialize
1167 // the java system classes, including StackOverflowError - depends on page
1168 // size.
1169 // The space needed for frames during startup is platform dependent. It
1170 // depends on word size, platform calling conventions, C frame layout and
1171 // interpreter/C1/C2 design decisions. Therefore this is given in a
1172 // platform (os/cpu) dependent constant.
1173 // To this, space for guard mechanisms is added, which depends on the
1174 // page size which again depends on the concrete system the VM is running
1175 // on. Space for libc guard pages is not included in this size.
1176 jint os::Posix::set_minimum_stack_sizes() {
1177 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1178
1179 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1180 JavaThread::stack_guard_zone_size() +
1181 JavaThread::stack_shadow_zone_size();
1182
1183 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1184 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1185
1186 size_t stack_size_in_bytes = ThreadStackSize * K;
1187 if (stack_size_in_bytes != 0 &&
1188 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1189 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1190 // ThreadStackSize so we go with "Java thread stack size" instead
1191 // of "ThreadStackSize" to be more friendly.
1192 tty->print_cr("\nThe Java thread stack size specified is too small. "
1193 "Specify at least " SIZE_FORMAT "k",
1194 _java_thread_min_stack_allowed / K);
1195 return JNI_ERR;
1196 }
1197
1198 // Make the stack size a multiple of the page size so that
1199 // the yellow/red zones can be guarded.
1200 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1201
1202 // Reminder: a compiler thread is a Java thread.
1203 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1204 JavaThread::stack_guard_zone_size() +
1205 JavaThread::stack_shadow_zone_size();
1206
1207 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1208 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1209
1210 stack_size_in_bytes = CompilerThreadStackSize * K;
1211 if (stack_size_in_bytes != 0 &&
1212 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1213 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1214 "Specify at least " SIZE_FORMAT "k",
1215 _compiler_thread_min_stack_allowed / K);
1216 return JNI_ERR;
1217 }
1218
1219 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1220 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1221
1222 stack_size_in_bytes = VMThreadStackSize * K;
1223 if (stack_size_in_bytes != 0 &&
1224 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1225 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1226 "Specify at least " SIZE_FORMAT "k",
1227 _vm_internal_thread_min_stack_allowed / K);
1228 return JNI_ERR;
1229 }
1230 return JNI_OK;
1231 }
1232
1233 // Called when creating the thread. The minimum stack sizes have already been calculated
1234 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1235 size_t stack_size;
1236 if (req_stack_size == 0) {
1237 stack_size = default_stack_size(thr_type);
1238 } else {
1239 stack_size = req_stack_size;
1240 }
1241
1242 switch (thr_type) {
1243 case os::java_thread:
1244 // Java threads use ThreadStackSize which default value can be
1245 // changed with the flag -Xss
1246 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1247 // no requested size and we have a more specific default value
1248 stack_size = JavaThread::stack_size_at_create();
1249 }
1250 stack_size = MAX2(stack_size,
1251 _java_thread_min_stack_allowed);
1252 break;
1253 case os::compiler_thread:
1254 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1255 // no requested size and we have a more specific default value
1256 stack_size = (size_t)(CompilerThreadStackSize * K);
1257 }
1258 stack_size = MAX2(stack_size,
1259 _compiler_thread_min_stack_allowed);
1260 break;
1261 case os::vm_thread:
1262 case os::pgc_thread:
1263 case os::cgc_thread:
1264 case os::watcher_thread:
1265 default: // presume the unknown thr_type is a VM internal
1266 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1267 // no requested size and we have a more specific default value
1268 stack_size = (size_t)(VMThreadStackSize * K);
1269 }
1270
1271 stack_size = MAX2(stack_size,
1272 _vm_internal_thread_min_stack_allowed);
1273 break;
1274 }
1275
1276 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1277 // Be careful not to round up to 0. Align down in that case.
1278 if (stack_size <= SIZE_MAX - vm_page_size()) {
1279 stack_size = align_up(stack_size, vm_page_size());
1280 } else {
1281 stack_size = align_down(stack_size, vm_page_size());
1282 }
1283
1284 return stack_size;
1285 }
1286
1287 Thread* os::ThreadCrashProtection::_protected_thread = NULL;
1288 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL;
1289 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0;
1290
1291 os::ThreadCrashProtection::ThreadCrashProtection() {
1292 }
1293
1294 /*
1295 * See the caveats for this class in os_posix.hpp
1296 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1297 * method and returns false. If none of the signals are raised, returns true.
1298 * The callback is supposed to provide the method that should be protected.
1299 */
1300 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1301 sigset_t saved_sig_mask;
1302
1303 Thread::muxAcquire(&_crash_mux, "CrashProtection");
1304
1305 _protected_thread = Thread::current_or_null();
1306 assert(_protected_thread != NULL, "Cannot crash protect a none Thread");
1307
1308 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1309 // since on at least some systems (OS X) siglongjmp will restore the mask
1310 // for the process, not the thread
1311 pthread_sigmask(0, NULL, &saved_sig_mask);
1312 if (sigsetjmp(_jmpbuf, 0) == 0) {
1313 // make sure we can see in the signal handler that we have crash protection
1314 // installed
1315 _crash_protection = this;
1316 cb.call();
1317 // and clear the crash protection
1318 _crash_protection = NULL;
1319 _protected_thread = NULL;
1320 Thread::muxRelease(&_crash_mux);
1321 return true;
1322 }
1323 // this happens when we siglongjmp() back
1324 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1325 _crash_protection = NULL;
1326 _protected_thread = NULL;
1327 Thread::muxRelease(&_crash_mux);
1328 return false;
1329 }
1330
1331 void os::ThreadCrashProtection::restore() {
1332 assert(_crash_protection != NULL, "must have crash protection");
1333 siglongjmp(_jmpbuf, 1);
1334 }
1335
1336 void os::ThreadCrashProtection::check_crash_protection(int sig,
1337 Thread* thread) {
1338
1339 if (thread != NULL &&
1340 thread == _protected_thread &&
1341 _crash_protection != NULL) {
1342
1343 if (sig == SIGSEGV || sig == SIGBUS) {
1344 _crash_protection->restore();
1345 }
1346 }
1347 }
1348
1349 #define check_with_errno(check_type, cond, msg) \
1350 do { \
1351 int err = errno; \
1352 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
1353 os::errno_name(err)); \
1354 } while (false)
1355
1356 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
1357 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
1358
1359 // POSIX unamed semaphores are not supported on OS X.
1360 #ifndef __APPLE__
1361
1362 PosixSemaphore::PosixSemaphore(uint value) {
1363 int ret = sem_init(&_semaphore, 0, value);
1364
1365 guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
1366 }
1367
1368 PosixSemaphore::~PosixSemaphore() {
1369 sem_destroy(&_semaphore);
1370 }
1371
1372 void PosixSemaphore::signal(uint count) {
1373 for (uint i = 0; i < count; i++) {
1374 int ret = sem_post(&_semaphore);
1375
1376 assert_with_errno(ret == 0, "sem_post failed");
1377 }
1378 }
1379
1380 void PosixSemaphore::wait() {
1381 int ret;
1382
1383 do {
1384 ret = sem_wait(&_semaphore);
1385 } while (ret != 0 && errno == EINTR);
1386
1387 assert_with_errno(ret == 0, "sem_wait failed");
1388 }
1389
1390 bool PosixSemaphore::trywait() {
1391 int ret;
1392
1393 do {
1394 ret = sem_trywait(&_semaphore);
1395 } while (ret != 0 && errno == EINTR);
1396
1397 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
1398
1399 return ret == 0;
1400 }
1401
1402 bool PosixSemaphore::timedwait(struct timespec ts) {
1403 while (true) {
1404 int result = sem_timedwait(&_semaphore, &ts);
1405 if (result == 0) {
1406 return true;
1407 } else if (errno == EINTR) {
1408 continue;
1409 } else if (errno == ETIMEDOUT) {
1410 return false;
1411 } else {
1412 assert_with_errno(false, "timedwait failed");
1413 return false;
1414 }
1415 }
1416 }
1417
1418 #endif // __APPLE__
1419
1420
1421 // Shared pthread_mutex/cond based PlatformEvent implementation.
1422 // Not currently usable by Solaris.
1423
1424 #ifndef SOLARIS
1425
1426 // Shared condattr object for use with relative timed-waits. Will be associated
1427 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1428 // but otherwise whatever default is used by the platform - generally the
1429 // time-of-day clock.
1430 static pthread_condattr_t _condAttr[1];
1431
1432 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1433 // all systems (e.g. FreeBSD) map the default to "normal".
1434 static pthread_mutexattr_t _mutexAttr[1];
1435
1436 // common basic initialization that is always supported
1437 static void pthread_init_common(void) {
1438 int status;
1439 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1440 fatal("pthread_condattr_init: %s", os::strerror(status));
1441 }
1442 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1443 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1444 }
1445 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1446 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1447 }
1448 }
1449
1450 // Not all POSIX types and API's are available on all notionally "posix"
1451 // platforms. If we have build-time support then we will check for actual
1452 // runtime support via dlopen/dlsym lookup. This allows for running on an
1453 // older OS version compared to the build platform. But if there is no
1454 // build time support then there cannot be any runtime support as we do not
1455 // know what the runtime types would be (for example clockid_t might be an
1456 // int or int64_t).
1457 //
1458 #ifdef SUPPORTS_CLOCK_MONOTONIC
1459
1460 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1461
1462 static int (*_clock_gettime)(clockid_t, struct timespec *);
1463 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1464
1465 static bool _use_clock_monotonic_condattr;
1466
1467 // Determine what POSIX API's are present and do appropriate
1468 // configuration.
1469 void os::Posix::init(void) {
1470
1471 // NOTE: no logging available when this is called. Put logging
1472 // statements in init_2().
1473
1474 // Copied from os::Linux::clock_init(). The duplication is temporary.
1475
1476 // 1. Check for CLOCK_MONOTONIC support.
1477
1478 void* handle = NULL;
1479
1480 // For linux we need librt, for other OS we can find
1481 // this function in regular libc.
1482 #ifdef NEEDS_LIBRT
1483 // We do dlopen's in this particular order due to bug in linux
1484 // dynamic loader (see 6348968) leading to crash on exit.
1485 handle = dlopen("librt.so.1", RTLD_LAZY);
1486 if (handle == NULL) {
1487 handle = dlopen("librt.so", RTLD_LAZY);
1488 }
1489 #endif
1490
1491 if (handle == NULL) {
1492 handle = RTLD_DEFAULT;
1493 }
1494
1495 _clock_gettime = NULL;
1496
1497 int (*clock_getres_func)(clockid_t, struct timespec*) =
1498 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1499 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1500 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1501 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1502 // We assume that if both clock_gettime and clock_getres support
1503 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1504 struct timespec res;
1505 struct timespec tp;
1506 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1507 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1508 // Yes, monotonic clock is supported.
1509 _clock_gettime = clock_gettime_func;
1510 } else {
1511 #ifdef NEEDS_LIBRT
1512 // Close librt if there is no monotonic clock.
1513 if (handle != RTLD_DEFAULT) {
1514 dlclose(handle);
1515 }
1516 #endif
1517 }
1518 }
1519
1520 // 2. Check for pthread_condattr_setclock support.
1521
1522 _pthread_condattr_setclock = NULL;
1523
1524 // libpthread is already loaded.
1525 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1526 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1527 "pthread_condattr_setclock");
1528 if (condattr_setclock_func != NULL) {
1529 _pthread_condattr_setclock = condattr_setclock_func;
1530 }
1531
1532 // Now do general initialization.
1533
1534 pthread_init_common();
1535
1536 int status;
1537 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1538 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1539 if (status == EINVAL) {
1540 _use_clock_monotonic_condattr = false;
1541 warning("Unable to use monotonic clock with relative timed-waits" \
1542 " - changes to the time-of-day clock may have adverse affects");
1543 } else {
1544 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1545 }
1546 } else {
1547 _use_clock_monotonic_condattr = true;
1548 }
1549 } else {
1550 _use_clock_monotonic_condattr = false;
1551 }
1552 }
1553
1554 void os::Posix::init_2(void) {
1555 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1556 (_clock_gettime != NULL ? "" : " not"));
1557 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1558 (_pthread_condattr_setclock != NULL ? "" : " not"));
1559 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1560 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1561 }
1562
1563 #else // !SUPPORTS_CLOCK_MONOTONIC
1564
1565 void os::Posix::init(void) {
1566 pthread_init_common();
1567 }
1568
1569 void os::Posix::init_2(void) {
1570 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1571 log_info(os)("Use of pthread_condattr_setclock is not supported");
1572 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1573 }
1574
1575 #endif // SUPPORTS_CLOCK_MONOTONIC
1576
1577 os::PlatformEvent::PlatformEvent() {
1578 int status = pthread_cond_init(_cond, _condAttr);
1579 assert_status(status == 0, status, "cond_init");
1580 status = pthread_mutex_init(_mutex, _mutexAttr);
1581 assert_status(status == 0, status, "mutex_init");
1582 _event = 0;
1583 _nParked = 0;
1584 }
1585
1586 // Utility to convert the given timeout to an absolute timespec
1587 // (based on the appropriate clock) to use with pthread_cond_timewait.
1588 // The clock queried here must be the clock used to manage the
1589 // timeout of the condition variable.
1590 //
1591 // The passed in timeout value is either a relative time in nanoseconds
1592 // or an absolute time in milliseconds. A relative timeout will be
1593 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1594 // the default time-of-day clock will be used.
1595
1596 // Given time is a 64-bit value and the time_t used in the timespec is
1597 // sometimes a signed-32-bit value we have to watch for overflow if times
1598 // way in the future are given. Further on Solaris versions
1599 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1600 // number of seconds, in abstime, is less than current_time + 100000000.
1601 // As it will be over 20 years before "now + 100000000" will overflow we can
1602 // ignore overflow and just impose a hard-limit on seconds using the value
1603 // of "now + 100000000". This places a limit on the timeout of about 3.17
1604 // years from "now".
1605 //
1606 #define MAX_SECS 100000000
1607
1608 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1609 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1610 // on which clock is being used).
1611 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1612 jlong now_part_sec, jlong unit) {
1613 time_t max_secs = now_sec + MAX_SECS;
1614
1615 jlong seconds = timeout / NANOUNITS;
1616 timeout %= NANOUNITS; // remaining nanos
1617
1618 if (seconds >= MAX_SECS) {
1619 // More seconds than we can add, so pin to max_secs.
1620 abstime->tv_sec = max_secs;
1621 abstime->tv_nsec = 0;
1622 } else {
1623 abstime->tv_sec = now_sec + seconds;
1624 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1625 if (nanos >= NANOUNITS) { // overflow
1626 abstime->tv_sec += 1;
1627 nanos -= NANOUNITS;
1628 }
1629 abstime->tv_nsec = nanos;
1630 }
1631 }
1632
1633 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1634 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1635 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1636 time_t max_secs = now_sec + MAX_SECS;
1637
1638 jlong seconds = deadline / MILLIUNITS;
1639 jlong millis = deadline % MILLIUNITS;
1640
1641 if (seconds >= max_secs) {
1642 // Absolute seconds exceeds allowed max, so pin to max_secs.
1643 abstime->tv_sec = max_secs;
1644 abstime->tv_nsec = 0;
1645 } else {
1646 abstime->tv_sec = seconds;
1647 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1648 }
1649 }
1650
1651 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1652 DEBUG_ONLY(int max_secs = MAX_SECS;)
1653
1654 if (timeout < 0) {
1655 timeout = 0;
1656 }
1657
1658 #ifdef SUPPORTS_CLOCK_MONOTONIC
1659
1660 if (_use_clock_monotonic_condattr && !isAbsolute) {
1661 struct timespec now;
1662 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1663 assert_status(status == 0, status, "clock_gettime");
1664 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1665 DEBUG_ONLY(max_secs += now.tv_sec;)
1666 } else {
1667
1668 #else
1669
1670 { // Match the block scope.
1671
1672 #endif // SUPPORTS_CLOCK_MONOTONIC
1673
1674 // Time-of-day clock is all we can reliably use.
1675 struct timeval now;
1676 int status = gettimeofday(&now, NULL);
1677 assert_status(status == 0, errno, "gettimeofday");
1678 if (isAbsolute) {
1679 unpack_abs_time(abstime, timeout, now.tv_sec);
1680 } else {
1681 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1682 }
1683 DEBUG_ONLY(max_secs += now.tv_sec;)
1684 }
1685
1686 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1687 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1688 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1689 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1690 }
1691
1692 // PlatformEvent
1693 //
1694 // Assumption:
1695 // Only one parker can exist on an event, which is why we allocate
1696 // them per-thread. Multiple unparkers can coexist.
1697 //
1698 // _event serves as a restricted-range semaphore.
1699 // -1 : thread is blocked, i.e. there is a waiter
1700 // 0 : neutral: thread is running or ready,
1701 // could have been signaled after a wait started
1702 // 1 : signaled - thread is running or ready
1703 //
1704 // Having three states allows for some detection of bad usage - see
1705 // comments on unpark().
1706
1707 void os::PlatformEvent::park() { // AKA "down()"
1708 // Transitions for _event:
1709 // -1 => -1 : illegal
1710 // 1 => 0 : pass - return immediately
1711 // 0 => -1 : block; then set _event to 0 before returning
1712
1713 // Invariant: Only the thread associated with the PlatformEvent
1714 // may call park().
1715 assert(_nParked == 0, "invariant");
1716
1717 int v;
1718
1719 // atomically decrement _event
1720 for (;;) {
1721 v = _event;
1722 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1723 }
1724 guarantee(v >= 0, "invariant");
1725
1726 if (v == 0) { // Do this the hard way by blocking ...
1727 int status = pthread_mutex_lock(_mutex);
1728 assert_status(status == 0, status, "mutex_lock");
1729 guarantee(_nParked == 0, "invariant");
1730 ++_nParked;
1731 while (_event < 0) {
1732 // OS-level "spurious wakeups" are ignored
1733 status = pthread_cond_wait(_cond, _mutex);
1734 assert_status(status == 0, status, "cond_wait");
1735 }
1736 --_nParked;
1737
1738 _event = 0;
1739 status = pthread_mutex_unlock(_mutex);
1740 assert_status(status == 0, status, "mutex_unlock");
1741 // Paranoia to ensure our locked and lock-free paths interact
1742 // correctly with each other.
1743 OrderAccess::fence();
1744 }
1745 guarantee(_event >= 0, "invariant");
1746 }
1747
1748 int os::PlatformEvent::park(jlong millis) {
1749 // Transitions for _event:
1750 // -1 => -1 : illegal
1751 // 1 => 0 : pass - return immediately
1752 // 0 => -1 : block; then set _event to 0 before returning
1753
1754 // Invariant: Only the thread associated with the Event/PlatformEvent
1755 // may call park().
1756 assert(_nParked == 0, "invariant");
1757
1758 int v;
1759 // atomically decrement _event
1760 for (;;) {
1761 v = _event;
1762 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1763 }
1764 guarantee(v >= 0, "invariant");
1765
1766 if (v == 0) { // Do this the hard way by blocking ...
1767 struct timespec abst;
1768 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1769
1770 int ret = OS_TIMEOUT;
1771 int status = pthread_mutex_lock(_mutex);
1772 assert_status(status == 0, status, "mutex_lock");
1773 guarantee(_nParked == 0, "invariant");
1774 ++_nParked;
1775
1776 while (_event < 0) {
1777 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1778 assert_status(status == 0 || status == ETIMEDOUT,
1779 status, "cond_timedwait");
1780 // OS-level "spurious wakeups" are ignored unless the archaic
1781 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1782 if (!FilterSpuriousWakeups) break;
1783 if (status == ETIMEDOUT) break;
1784 }
1785 --_nParked;
1786
1787 if (_event >= 0) {
1788 ret = OS_OK;
1789 }
1790
1791 _event = 0;
1792 status = pthread_mutex_unlock(_mutex);
1793 assert_status(status == 0, status, "mutex_unlock");
1794 // Paranoia to ensure our locked and lock-free paths interact
1795 // correctly with each other.
1796 OrderAccess::fence();
1797 return ret;
1798 }
1799 return OS_OK;
1800 }
1801
1802 void os::PlatformEvent::unpark() {
1803 // Transitions for _event:
1804 // 0 => 1 : just return
1805 // 1 => 1 : just return
1806 // -1 => either 0 or 1; must signal target thread
1807 // That is, we can safely transition _event from -1 to either
1808 // 0 or 1.
1809 // See also: "Semaphores in Plan 9" by Mullender & Cox
1810 //
1811 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1812 // that it will take two back-to-back park() calls for the owning
1813 // thread to block. This has the benefit of forcing a spurious return
1814 // from the first park() call after an unpark() call which will help
1815 // shake out uses of park() and unpark() without checking state conditions
1816 // properly. This spurious return doesn't manifest itself in any user code
1817 // but only in the correctly written condition checking loops of ObjectMonitor,
1818 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1819
1820 if (Atomic::xchg(1, &_event) >= 0) return;
1821
1822 int status = pthread_mutex_lock(_mutex);
1823 assert_status(status == 0, status, "mutex_lock");
1824 int anyWaiters = _nParked;
1825 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1826 status = pthread_mutex_unlock(_mutex);
1827 assert_status(status == 0, status, "mutex_unlock");
1828
1829 // Note that we signal() *after* dropping the lock for "immortal" Events.
1830 // This is safe and avoids a common class of futile wakeups. In rare
1831 // circumstances this can cause a thread to return prematurely from
1832 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1833 // will simply re-test the condition and re-park itself.
1834 // This provides particular benefit if the underlying platform does not
1835 // provide wait morphing.
1836
1837 if (anyWaiters != 0) {
1838 status = pthread_cond_signal(_cond);
1839 assert_status(status == 0, status, "cond_signal");
1840 }
1841 }
1842
1843 // JSR166 support
1844
1845 os::PlatformParker::PlatformParker() {
1846 int status;
1847 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1848 assert_status(status == 0, status, "cond_init rel");
1849 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
1850 assert_status(status == 0, status, "cond_init abs");
1851 status = pthread_mutex_init(_mutex, _mutexAttr);
1852 assert_status(status == 0, status, "mutex_init");
1853 _cur_index = -1; // mark as unused
1854 }
1855
1856 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
1857 // sets count to 1 and signals condvar. Only one thread ever waits
1858 // on the condvar. Contention seen when trying to park implies that someone
1859 // is unparking you, so don't wait. And spurious returns are fine, so there
1860 // is no need to track notifications.
1861
1862 void Parker::park(bool isAbsolute, jlong time) {
1863
1864 // Optional fast-path check:
1865 // Return immediately if a permit is available.
1866 // We depend on Atomic::xchg() having full barrier semantics
1867 // since we are doing a lock-free update to _counter.
1868 if (Atomic::xchg(0, &_counter) > 0) return;
1869
1870 Thread* thread = Thread::current();
1871 assert(thread->is_Java_thread(), "Must be JavaThread");
1872 JavaThread *jt = (JavaThread *)thread;
1873
1874 // Optional optimization -- avoid state transitions if there's
1875 // an interrupt pending.
1876 if (Thread::is_interrupted(thread, false)) {
1877 return;
1878 }
1879
1880 // Next, demultiplex/decode time arguments
1881 struct timespec absTime;
1882 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
1883 return;
1884 }
1885 if (time > 0) {
1886 to_abstime(&absTime, time, isAbsolute);
1887 }
1888
1889 // Enter safepoint region
1890 // Beware of deadlocks such as 6317397.
1891 // The per-thread Parker:: mutex is a classic leaf-lock.
1892 // In particular a thread must never block on the Threads_lock while
1893 // holding the Parker:: mutex. If safepoints are pending both the
1894 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
1895 ThreadBlockInVM tbivm(jt);
1896
1897 // Don't wait if cannot get lock since interference arises from
1898 // unparking. Also re-check interrupt before trying wait.
1899 if (Thread::is_interrupted(thread, false) ||
1900 pthread_mutex_trylock(_mutex) != 0) {
1901 return;
1902 }
1903
1904 int status;
1905 if (_counter > 0) { // no wait needed
1906 _counter = 0;
1907 status = pthread_mutex_unlock(_mutex);
1908 assert_status(status == 0, status, "invariant");
1909 // Paranoia to ensure our locked and lock-free paths interact
1910 // correctly with each other and Java-level accesses.
1911 OrderAccess::fence();
1912 return;
1913 }
1914
1915 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
1916 jt->set_suspend_equivalent();
1917 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
1918
1919 assert(_cur_index == -1, "invariant");
1920 if (time == 0) {
1921 _cur_index = REL_INDEX; // arbitrary choice when not timed
1922 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
1923 assert_status(status == 0, status, "cond_timedwait");
1924 }
1925 else {
1926 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
1927 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
1928 assert_status(status == 0 || status == ETIMEDOUT,
1929 status, "cond_timedwait");
1930 }
1931 _cur_index = -1;
1932
1933 _counter = 0;
1934 status = pthread_mutex_unlock(_mutex);
1935 assert_status(status == 0, status, "invariant");
1936 // Paranoia to ensure our locked and lock-free paths interact
1937 // correctly with each other and Java-level accesses.
1938 OrderAccess::fence();
1939
1940 // If externally suspended while waiting, re-suspend
1941 if (jt->handle_special_suspend_equivalent_condition()) {
1942 jt->java_suspend_self();
1943 }
1944 }
1945
1946 void Parker::unpark() {
1947 int status = pthread_mutex_lock(_mutex);
1948 assert_status(status == 0, status, "invariant");
1949 const int s = _counter;
1950 _counter = 1;
1951 // must capture correct index before unlocking
1952 int index = _cur_index;
1953 status = pthread_mutex_unlock(_mutex);
1954 assert_status(status == 0, status, "invariant");
1955
1956 // Note that we signal() *after* dropping the lock for "immortal" Events.
1957 // This is safe and avoids a common class of futile wakeups. In rare
1958 // circumstances this can cause a thread to return prematurely from
1959 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1960 // will simply re-test the condition and re-park itself.
1961 // This provides particular benefit if the underlying platform does not
1962 // provide wait morphing.
1963
1964 if (s < 1 && index != -1) {
1965 // thread is definitely parked
1966 status = pthread_cond_signal(&_cond[index]);
1967 assert_status(status == 0, status, "invariant");
1968 }
1969 }
1970
1971
1972 #endif // !SOLARIS