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 "jvm.h"
26 #include "utilities/globalDefinitions.hpp"
27 #include "runtime/frame.inline.hpp"
28 #include "runtime/interfaceSupport.hpp"
29 #include "runtime/os.hpp"
30 #include "utilities/align.hpp"
31 #include "utilities/macros.hpp"
32 #include "utilities/vmError.hpp"
33
34 #ifndef __APPLE__
35 // POSIX unamed semaphores are not supported on OS X.
36 #include "semaphore_posix.hpp"
37 #endif
38
39 #include <dlfcn.h>
40 #include <pthread.h>
41 #include <semaphore.h>
42 #include <signal.h>
43 #include <sys/mman.h>
44 #include <sys/resource.h>
45 #include <sys/utsname.h>
46 #include <time.h>
47 #include <unistd.h>
48
49 // Todo: provide a os::get_max_process_id() or similar. Number of processes
50 // may have been configured, can be read more accurately from proc fs etc.
51 #ifndef MAX_PID
52 #define MAX_PID INT_MAX
53 #endif
54 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
55
56 #ifndef MAP_ANONYMOUS
57 #define MAP_ANONYMOUS MAP_ANON
58 #endif
59
60 #define check_with_errno(check_type, cond, msg) \
61 do { \
62 int err = errno; \
63 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
64 os::errno_name(err)); \
65 } while (false)
66
67 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
68 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
69
70 // Check core dump limit and report possible place where core can be found
71 void os::check_dump_limit(char* buffer, size_t bufferSize) {
72 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) {
73 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line");
74 VMError::record_coredump_status(buffer, false);
75 return;
76 }
77
78 int n;
79 struct rlimit rlim;
80 bool success;
81
82 char core_path[PATH_MAX];
83 n = get_core_path(core_path, PATH_MAX);
84
85 if (n <= 0) {
86 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());
87 success = true;
88 #ifdef LINUX
89 } else if (core_path[0] == '"') { // redirect to user process
90 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);
91 success = true;
92 #endif
93 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
94 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);
95 success = true;
96 } else {
97 switch(rlim.rlim_cur) {
98 case RLIM_INFINITY:
99 jio_snprintf(buffer, bufferSize, "%s", core_path);
100 success = true;
101 break;
102 case 0:
103 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
104 success = false;
105 break;
106 default:
107 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);
108 success = true;
109 break;
110 }
111 }
112
113 VMError::record_coredump_status(buffer, success);
114 }
115
116 int os::get_native_stack(address* stack, int frames, int toSkip) {
117 int frame_idx = 0;
118 int num_of_frames; // number of frames captured
119 frame fr = os::current_frame();
120 while (fr.pc() && frame_idx < frames) {
121 if (toSkip > 0) {
122 toSkip --;
123 } else {
124 stack[frame_idx ++] = fr.pc();
125 }
126 if (fr.fp() == NULL || fr.cb() != NULL ||
127 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;
128
129 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
130 fr = os::get_sender_for_C_frame(&fr);
131 } else {
132 break;
133 }
134 }
135 num_of_frames = frame_idx;
136 for (; frame_idx < frames; frame_idx ++) {
137 stack[frame_idx] = NULL;
138 }
139
140 return num_of_frames;
141 }
142
143
144 bool os::unsetenv(const char* name) {
145 assert(name != NULL, "Null pointer");
146 return (::unsetenv(name) == 0);
147 }
148
149 int os::get_last_error() {
150 return errno;
151 }
152
153 bool os::is_debugger_attached() {
154 // not implemented
155 return false;
156 }
157
158 void os::wait_for_keypress_at_exit(void) {
159 // don't do anything on posix platforms
160 return;
161 }
162
163 int os::create_file_for_heap(const char* dir) {
164
165 const char name_template[] = "/jvmheap.XXXXXX";
166
167 char *fullname = (char*)os::malloc((strlen(dir) + strlen(name_template) + 1), mtInternal);
168 if (fullname == NULL) {
169 vm_exit_during_initialization(err_msg("Malloc failed during creation of backing file for heap (%s)", os::strerror(errno)));
170 return -1;
171 }
172 (void)strncpy(fullname, dir, strlen(dir)+1);
173 (void)strncat(fullname, name_template, strlen(name_template));
174
175 os::native_path(fullname);
176
177 sigset_t set, oldset;
178 int ret = sigfillset(&set);
179 assert_with_errno(ret == 0, "sigfillset returned error");
180
181 // set the file creation mask.
182 mode_t file_mode = S_IRUSR | S_IWUSR;
183
184 // create a new file.
185 int fd = mkstemp(fullname);
186
187 if (fd < 0) {
188 warning("Could not create file for heap with template %s", fullname);
189 os::free(fullname);
190 return -1;
191 }
192
193 // delete the name from the filesystem. When 'fd' is closed, the file (and space) will be deleted.
194 ret = unlink(fullname);
195 assert_with_errno(ret == 0, "unlink returned error");
196
197 os::free(fullname);
198 return fd;
199 }
200
201 static char* reserve_mmapped_memory(size_t bytes, char* requested_addr) {
202 char * addr;
203 int flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
204 if (requested_addr != NULL) {
205 assert((uintptr_t)requested_addr % os::vm_page_size() == 0, "Requested address should be aligned to OS page size");
206 flags |= MAP_FIXED;
207 }
208
209 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
210 // touch an uncommitted page. Otherwise, the read/write might
211 // succeed if we have enough swap space to back the physical page.
212 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
213 flags, -1, 0);
214
215 if (addr != MAP_FAILED) {
216 MemTracker::record_virtual_memory_reserve((address)addr, bytes, CALLER_PC);
217 return addr;
218 }
219 return NULL;
220 }
221
222 static int util_posix_fallocate(int fd, off_t offset, off_t len) {
223 #ifdef __APPLE__
224 fstore_t store = { F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, len };
225 // First we try to get a continuous chunk of disk space
226 int ret = fcntl(fd, F_PREALLOCATE, &store);
227 if (ret == -1) {
228 // Maybe we are too fragmented, try to allocate non-continuous range
229 store.fst_flags = F_ALLOCATEALL;
230 ret = fcntl(fd, F_PREALLOCATE, &store);
231 }
232 if(ret != -1) {
233 return ftruncate(fd, len);
234 }
235 return -1;
236 #else
237 return posix_fallocate(fd, offset, len);
238 #endif
239 }
240
241 // Map the given address range to the provided file descriptor.
242 char* os::map_memory_to_file(char* base, size_t size, int fd) {
243 assert(fd != -1, "File descriptor is not valid");
244
245 // allocate space for the file
246 if (util_posix_fallocate(fd, 0, (off_t)size) != 0) {
247 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory."));
248 return NULL;
249 }
250
251 int prot = PROT_READ | PROT_WRITE;
252 int flags = MAP_SHARED;
253 if (base != NULL) {
254 flags |= MAP_FIXED;
255 }
256 char* addr = (char*)mmap(base, size, prot, flags, fd, 0);
257
258 if (addr == MAP_FAILED) {
259 return NULL;
260 }
261 if (base != NULL && addr != base) {
262 if (!os::release_memory(addr, size)) {
263 warning("Could not release memory on unsuccessful file mapping");
264 }
265 return NULL;
266 }
267 return addr;
268 }
269
270 char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) {
271 assert(fd != -1, "File descriptor is not valid");
272 assert(base != NULL, "Base cannot be NULL");
273
274 return map_memory_to_file(base, size, fd);
275 }
276
277 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
278 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
279 // rather than unmapping and remapping the whole chunk to get requested alignment.
280 char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) {
281 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
282 "Alignment must be a multiple of allocation granularity (page size)");
283 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
284
285 size_t extra_size = size + alignment;
286 assert(extra_size >= size, "overflow, size is too large to allow alignment");
287
288 char* extra_base;
289 if (file_desc != -1) {
290 // For file mapping, we do not call os:reserve_memory(extra_size, NULL, alignment, file_desc) because
291 // we need to deal with shrinking of the file space later when we release extra memory after alignment.
292 // We also cannot called os:reserve_memory() with file_desc set to -1 because on aix we might get SHM memory.
293 // So here to call a helper function while reserve memory for us. After we have a aligned base,
294 // we will replace anonymous mapping with file mapping.
295 extra_base = reserve_mmapped_memory(extra_size, NULL);
296 if (extra_base != NULL) {
297 MemTracker::record_virtual_memory_reserve((address)extra_base, extra_size, CALLER_PC);
298 }
299 } else {
300 extra_base = os::reserve_memory(extra_size, NULL, alignment);
301 }
302
303 if (extra_base == NULL) {
304 return NULL;
305 }
306
307 // Do manual alignment
308 char* aligned_base = align_up(extra_base, alignment);
309
310 // [ | | ]
311 // ^ extra_base
312 // ^ extra_base + begin_offset == aligned_base
313 // extra_base + begin_offset + size ^
314 // extra_base + extra_size ^
315 // |<>| == begin_offset
316 // end_offset == |<>|
317 size_t begin_offset = aligned_base - extra_base;
318 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
319
320 if (begin_offset > 0) {
321 os::release_memory(extra_base, begin_offset);
322 }
323
324 if (end_offset > 0) {
325 os::release_memory(extra_base + begin_offset + size, end_offset);
326 }
327
328 if (file_desc != -1) {
329 // After we have an aligned address, we can replace anonymous mapping with file mapping
330 if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) {
331 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
332 }
333 MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC);
334 }
335 return aligned_base;
336 }
337
338 int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
339 return vsnprintf(buf, len, fmt, args);
340 }
341
342 int os::get_fileno(FILE* fp) {
343 return NOT_AIX(::)fileno(fp);
344 }
345
346 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
347 return gmtime_r(clock, res);
348 }
349
350 void os::Posix::print_load_average(outputStream* st) {
351 st->print("load average:");
352 double loadavg[3];
353 os::loadavg(loadavg, 3);
354 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
355 st->cr();
356 }
357
358 void os::Posix::print_rlimit_info(outputStream* st) {
359 st->print("rlimit:");
360 struct rlimit rlim;
361
362 st->print(" STACK ");
363 getrlimit(RLIMIT_STACK, &rlim);
364 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
365 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
366
367 st->print(", CORE ");
368 getrlimit(RLIMIT_CORE, &rlim);
369 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
370 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
371
372 // Isn't there on solaris
373 #if defined(AIX)
374 st->print(", NPROC ");
375 st->print("%d", sysconf(_SC_CHILD_MAX));
376 #elif !defined(SOLARIS)
377 st->print(", NPROC ");
378 getrlimit(RLIMIT_NPROC, &rlim);
379 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
380 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
381 #endif
382
383 st->print(", NOFILE ");
384 getrlimit(RLIMIT_NOFILE, &rlim);
385 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
386 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
387
388 st->print(", AS ");
389 getrlimit(RLIMIT_AS, &rlim);
390 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
391 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
392
393 st->print(", DATA ");
394 getrlimit(RLIMIT_DATA, &rlim);
395 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
396 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
397
398 st->print(", FSIZE ");
399 getrlimit(RLIMIT_FSIZE, &rlim);
400 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
401 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
402
403 st->cr();
404 }
405
406 void os::Posix::print_uname_info(outputStream* st) {
407 // kernel
408 st->print("uname:");
409 struct utsname name;
410 uname(&name);
411 st->print("%s ", name.sysname);
412 #ifdef ASSERT
413 st->print("%s ", name.nodename);
414 #endif
415 st->print("%s ", name.release);
416 st->print("%s ", name.version);
417 st->print("%s", name.machine);
418 st->cr();
419 }
420
421 bool os::get_host_name(char* buf, size_t buflen) {
422 struct utsname name;
423 uname(&name);
424 jio_snprintf(buf, buflen, "%s", name.nodename);
425 return true;
426 }
427
428 bool os::has_allocatable_memory_limit(julong* limit) {
429 struct rlimit rlim;
430 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
431 // if there was an error when calling getrlimit, assume that there is no limitation
432 // on virtual memory.
433 bool result;
434 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
435 result = false;
436 } else {
437 *limit = (julong)rlim.rlim_cur;
438 result = true;
439 }
440 #ifdef _LP64
441 return result;
442 #else
443 // arbitrary virtual space limit for 32 bit Unices found by testing. If
444 // getrlimit above returned a limit, bound it with this limit. Otherwise
445 // directly use it.
446 const julong max_virtual_limit = (julong)3800*M;
447 if (result) {
448 *limit = MIN2(*limit, max_virtual_limit);
449 } else {
450 *limit = max_virtual_limit;
451 }
452
453 // bound by actually allocatable memory. The algorithm uses two bounds, an
454 // upper and a lower limit. The upper limit is the current highest amount of
455 // memory that could not be allocated, the lower limit is the current highest
456 // amount of memory that could be allocated.
457 // The algorithm iteratively refines the result by halving the difference
458 // between these limits, updating either the upper limit (if that value could
459 // not be allocated) or the lower limit (if the that value could be allocated)
460 // until the difference between these limits is "small".
461
462 // the minimum amount of memory we care about allocating.
463 const julong min_allocation_size = M;
464
465 julong upper_limit = *limit;
466
467 // first check a few trivial cases
468 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
469 *limit = upper_limit;
470 } else if (!is_allocatable(min_allocation_size)) {
471 // we found that not even min_allocation_size is allocatable. Return it
472 // anyway. There is no point to search for a better value any more.
473 *limit = min_allocation_size;
474 } else {
475 // perform the binary search.
476 julong lower_limit = min_allocation_size;
477 while ((upper_limit - lower_limit) > min_allocation_size) {
478 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
479 temp_limit = align_down(temp_limit, min_allocation_size);
480 if (is_allocatable(temp_limit)) {
481 lower_limit = temp_limit;
482 } else {
483 upper_limit = temp_limit;
484 }
485 }
486 *limit = lower_limit;
487 }
488 return true;
489 #endif
490 }
491
492 const char* os::get_current_directory(char *buf, size_t buflen) {
493 return getcwd(buf, buflen);
494 }
495
496 FILE* os::open(int fd, const char* mode) {
497 return ::fdopen(fd, mode);
498 }
499
500 void os::flockfile(FILE* fp) {
501 ::flockfile(fp);
502 }
503
504 void os::funlockfile(FILE* fp) {
505 ::funlockfile(fp);
506 }
507
508 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
509 // which is used to find statically linked in agents.
510 // Parameters:
511 // sym_name: Symbol in library we are looking for
512 // lib_name: Name of library to look in, NULL for shared libs.
513 // is_absolute_path == true if lib_name is absolute path to agent
514 // such as "/a/b/libL.so"
515 // == false if only the base name of the library is passed in
516 // such as "L"
517 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
518 bool is_absolute_path) {
519 char *agent_entry_name;
520 size_t len;
521 size_t name_len;
522 size_t prefix_len = strlen(JNI_LIB_PREFIX);
523 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
524 const char *start;
525
526 if (lib_name != NULL) {
527 name_len = strlen(lib_name);
528 if (is_absolute_path) {
529 // Need to strip path, prefix and suffix
530 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
531 lib_name = ++start;
532 }
533 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
534 return NULL;
535 }
536 lib_name += prefix_len;
537 name_len = strlen(lib_name) - suffix_len;
538 }
539 }
540 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
541 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
542 if (agent_entry_name == NULL) {
543 return NULL;
544 }
545 strcpy(agent_entry_name, sym_name);
546 if (lib_name != NULL) {
547 strcat(agent_entry_name, "_");
548 strncat(agent_entry_name, lib_name, name_len);
549 }
550 return agent_entry_name;
551 }
552
553 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
554 assert(thread == Thread::current(), "thread consistency check");
555
556 ParkEvent * const slp = thread->_SleepEvent ;
557 slp->reset() ;
558 OrderAccess::fence() ;
559
560 if (interruptible) {
561 jlong prevtime = javaTimeNanos();
562
563 for (;;) {
564 if (os::is_interrupted(thread, true)) {
565 return OS_INTRPT;
566 }
567
568 jlong newtime = javaTimeNanos();
569
570 if (newtime - prevtime < 0) {
571 // time moving backwards, should only happen if no monotonic clock
572 // not a guarantee() because JVM should not abort on kernel/glibc bugs
573 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
574 } else {
575 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
576 }
577
578 if (millis <= 0) {
579 return OS_OK;
580 }
581
582 prevtime = newtime;
583
584 {
585 assert(thread->is_Java_thread(), "sanity check");
586 JavaThread *jt = (JavaThread *) thread;
587 ThreadBlockInVM tbivm(jt);
588 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
589
590 jt->set_suspend_equivalent();
591 // cleared by handle_special_suspend_equivalent_condition() or
592 // java_suspend_self() via check_and_wait_while_suspended()
593
594 slp->park(millis);
595
596 // were we externally suspended while we were waiting?
597 jt->check_and_wait_while_suspended();
598 }
599 }
600 } else {
601 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
602 jlong prevtime = javaTimeNanos();
603
604 for (;;) {
605 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
606 // the 1st iteration ...
607 jlong newtime = javaTimeNanos();
608
609 if (newtime - prevtime < 0) {
610 // time moving backwards, should only happen if no monotonic clock
611 // not a guarantee() because JVM should not abort on kernel/glibc bugs
612 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
613 } else {
614 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
615 }
616
617 if (millis <= 0) break ;
618
619 prevtime = newtime;
620 slp->park(millis);
621 }
622 return OS_OK ;
623 }
624 }
625
626 ////////////////////////////////////////////////////////////////////////////////
627 // interrupt support
628
629 void os::interrupt(Thread* thread) {
630 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
631 "possibility of dangling Thread pointer");
632
633 OSThread* osthread = thread->osthread();
634
635 if (!osthread->interrupted()) {
636 osthread->set_interrupted(true);
637 // More than one thread can get here with the same value of osthread,
638 // resulting in multiple notifications. We do, however, want the store
639 // to interrupted() to be visible to other threads before we execute unpark().
640 OrderAccess::fence();
641 ParkEvent * const slp = thread->_SleepEvent ;
642 if (slp != NULL) slp->unpark() ;
643 }
644
645 // For JSR166. Unpark even if interrupt status already was set
646 if (thread->is_Java_thread())
647 ((JavaThread*)thread)->parker()->unpark();
648
649 ParkEvent * ev = thread->_ParkEvent ;
650 if (ev != NULL) ev->unpark() ;
651
652 }
653
654 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
655 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
656 "possibility of dangling Thread pointer");
657
658 OSThread* osthread = thread->osthread();
659
660 bool interrupted = osthread->interrupted();
661
662 // NOTE that since there is no "lock" around the interrupt and
663 // is_interrupted operations, there is the possibility that the
664 // interrupted flag (in osThread) will be "false" but that the
665 // low-level events will be in the signaled state. This is
666 // intentional. The effect of this is that Object.wait() and
667 // LockSupport.park() will appear to have a spurious wakeup, which
668 // is allowed and not harmful, and the possibility is so rare that
669 // it is not worth the added complexity to add yet another lock.
670 // For the sleep event an explicit reset is performed on entry
671 // to os::sleep, so there is no early return. It has also been
672 // recommended not to put the interrupted flag into the "event"
673 // structure because it hides the issue.
674 if (interrupted && clear_interrupted) {
675 osthread->set_interrupted(false);
676 // consider thread->_SleepEvent->reset() ... optional optimization
677 }
678
679 return interrupted;
680 }
681
682
683
684 static const struct {
685 int sig; const char* name;
686 }
687 g_signal_info[] =
688 {
689 { SIGABRT, "SIGABRT" },
690 #ifdef SIGAIO
691 { SIGAIO, "SIGAIO" },
692 #endif
693 { SIGALRM, "SIGALRM" },
694 #ifdef SIGALRM1
695 { SIGALRM1, "SIGALRM1" },
696 #endif
697 { SIGBUS, "SIGBUS" },
698 #ifdef SIGCANCEL
699 { SIGCANCEL, "SIGCANCEL" },
700 #endif
701 { SIGCHLD, "SIGCHLD" },
702 #ifdef SIGCLD
703 { SIGCLD, "SIGCLD" },
704 #endif
705 { SIGCONT, "SIGCONT" },
706 #ifdef SIGCPUFAIL
707 { SIGCPUFAIL, "SIGCPUFAIL" },
708 #endif
709 #ifdef SIGDANGER
710 { SIGDANGER, "SIGDANGER" },
711 #endif
712 #ifdef SIGDIL
713 { SIGDIL, "SIGDIL" },
714 #endif
715 #ifdef SIGEMT
716 { SIGEMT, "SIGEMT" },
717 #endif
718 { SIGFPE, "SIGFPE" },
719 #ifdef SIGFREEZE
720 { SIGFREEZE, "SIGFREEZE" },
721 #endif
722 #ifdef SIGGFAULT
723 { SIGGFAULT, "SIGGFAULT" },
724 #endif
725 #ifdef SIGGRANT
726 { SIGGRANT, "SIGGRANT" },
727 #endif
728 { SIGHUP, "SIGHUP" },
729 { SIGILL, "SIGILL" },
730 { SIGINT, "SIGINT" },
731 #ifdef SIGIO
732 { SIGIO, "SIGIO" },
733 #endif
734 #ifdef SIGIOINT
735 { SIGIOINT, "SIGIOINT" },
736 #endif
737 #ifdef SIGIOT
738 // SIGIOT is there for BSD compatibility, but on most Unices just a
739 // synonym for SIGABRT. The result should be "SIGABRT", not
740 // "SIGIOT".
741 #if (SIGIOT != SIGABRT )
742 { SIGIOT, "SIGIOT" },
743 #endif
744 #endif
745 #ifdef SIGKAP
746 { SIGKAP, "SIGKAP" },
747 #endif
748 { SIGKILL, "SIGKILL" },
749 #ifdef SIGLOST
750 { SIGLOST, "SIGLOST" },
751 #endif
752 #ifdef SIGLWP
753 { SIGLWP, "SIGLWP" },
754 #endif
755 #ifdef SIGLWPTIMER
756 { SIGLWPTIMER, "SIGLWPTIMER" },
757 #endif
758 #ifdef SIGMIGRATE
759 { SIGMIGRATE, "SIGMIGRATE" },
760 #endif
761 #ifdef SIGMSG
762 { SIGMSG, "SIGMSG" },
763 #endif
764 { SIGPIPE, "SIGPIPE" },
765 #ifdef SIGPOLL
766 { SIGPOLL, "SIGPOLL" },
767 #endif
768 #ifdef SIGPRE
769 { SIGPRE, "SIGPRE" },
770 #endif
771 { SIGPROF, "SIGPROF" },
772 #ifdef SIGPTY
773 { SIGPTY, "SIGPTY" },
774 #endif
775 #ifdef SIGPWR
776 { SIGPWR, "SIGPWR" },
777 #endif
778 { SIGQUIT, "SIGQUIT" },
779 #ifdef SIGRECONFIG
780 { SIGRECONFIG, "SIGRECONFIG" },
781 #endif
782 #ifdef SIGRECOVERY
783 { SIGRECOVERY, "SIGRECOVERY" },
784 #endif
785 #ifdef SIGRESERVE
786 { SIGRESERVE, "SIGRESERVE" },
787 #endif
788 #ifdef SIGRETRACT
789 { SIGRETRACT, "SIGRETRACT" },
790 #endif
791 #ifdef SIGSAK
792 { SIGSAK, "SIGSAK" },
793 #endif
794 { SIGSEGV, "SIGSEGV" },
795 #ifdef SIGSOUND
796 { SIGSOUND, "SIGSOUND" },
797 #endif
798 #ifdef SIGSTKFLT
799 { SIGSTKFLT, "SIGSTKFLT" },
800 #endif
801 { SIGSTOP, "SIGSTOP" },
802 { SIGSYS, "SIGSYS" },
803 #ifdef SIGSYSERROR
804 { SIGSYSERROR, "SIGSYSERROR" },
805 #endif
806 #ifdef SIGTALRM
807 { SIGTALRM, "SIGTALRM" },
808 #endif
809 { SIGTERM, "SIGTERM" },
810 #ifdef SIGTHAW
811 { SIGTHAW, "SIGTHAW" },
812 #endif
813 { SIGTRAP, "SIGTRAP" },
814 #ifdef SIGTSTP
815 { SIGTSTP, "SIGTSTP" },
816 #endif
817 { SIGTTIN, "SIGTTIN" },
818 { SIGTTOU, "SIGTTOU" },
819 #ifdef SIGURG
820 { SIGURG, "SIGURG" },
821 #endif
822 { SIGUSR1, "SIGUSR1" },
823 { SIGUSR2, "SIGUSR2" },
824 #ifdef SIGVIRT
825 { SIGVIRT, "SIGVIRT" },
826 #endif
827 { SIGVTALRM, "SIGVTALRM" },
828 #ifdef SIGWAITING
829 { SIGWAITING, "SIGWAITING" },
830 #endif
831 #ifdef SIGWINCH
832 { SIGWINCH, "SIGWINCH" },
833 #endif
834 #ifdef SIGWINDOW
835 { SIGWINDOW, "SIGWINDOW" },
836 #endif
837 { SIGXCPU, "SIGXCPU" },
838 { SIGXFSZ, "SIGXFSZ" },
839 #ifdef SIGXRES
840 { SIGXRES, "SIGXRES" },
841 #endif
842 { -1, NULL }
843 };
844
845 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
846 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
847
848 const char* ret = NULL;
849
850 #ifdef SIGRTMIN
851 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
852 if (sig == SIGRTMIN) {
853 ret = "SIGRTMIN";
854 } else if (sig == SIGRTMAX) {
855 ret = "SIGRTMAX";
856 } else {
857 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
858 return out;
859 }
860 }
861 #endif
862
863 if (sig > 0) {
864 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
865 if (g_signal_info[idx].sig == sig) {
866 ret = g_signal_info[idx].name;
867 break;
868 }
869 }
870 }
871
872 if (!ret) {
873 if (!is_valid_signal(sig)) {
874 ret = "INVALID";
875 } else {
876 ret = "UNKNOWN";
877 }
878 }
879
880 if (out && outlen > 0) {
881 strncpy(out, ret, outlen);
882 out[outlen - 1] = '\0';
883 }
884 return out;
885 }
886
887 int os::Posix::get_signal_number(const char* signal_name) {
888 char tmp[30];
889 const char* s = signal_name;
890 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
891 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
892 s = tmp;
893 }
894 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
895 if (strcmp(g_signal_info[idx].name, s) == 0) {
896 return g_signal_info[idx].sig;
897 }
898 }
899 return -1;
900 }
901
902 int os::get_signal_number(const char* signal_name) {
903 return os::Posix::get_signal_number(signal_name);
904 }
905
906 // Returns true if signal number is valid.
907 bool os::Posix::is_valid_signal(int sig) {
908 // MacOS not really POSIX compliant: sigaddset does not return
909 // an error for invalid signal numbers. However, MacOS does not
910 // support real time signals and simply seems to have just 33
911 // signals with no holes in the signal range.
912 #ifdef __APPLE__
913 return sig >= 1 && sig < NSIG;
914 #else
915 // Use sigaddset to check for signal validity.
916 sigset_t set;
917 sigemptyset(&set);
918 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
919 return false;
920 }
921 return true;
922 #endif
923 }
924
925 // Returns:
926 // NULL for an invalid signal number
927 // "SIG<num>" for a valid but unknown signal number
928 // signal name otherwise.
929 const char* os::exception_name(int sig, char* buf, size_t size) {
930 if (!os::Posix::is_valid_signal(sig)) {
931 return NULL;
932 }
933 const char* const name = os::Posix::get_signal_name(sig, buf, size);
934 if (strcmp(name, "UNKNOWN") == 0) {
935 jio_snprintf(buf, size, "SIG%d", sig);
936 }
937 return buf;
938 }
939
940 #define NUM_IMPORTANT_SIGS 32
941 // Returns one-line short description of a signal set in a user provided buffer.
942 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
943 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
944 // Note: for shortness, just print out the first 32. That should
945 // cover most of the useful ones, apart from realtime signals.
946 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
947 const int rc = sigismember(set, sig);
948 if (rc == -1 && errno == EINVAL) {
949 buffer[sig-1] = '?';
950 } else {
951 buffer[sig-1] = rc == 0 ? '0' : '1';
952 }
953 }
954 buffer[NUM_IMPORTANT_SIGS] = 0;
955 return buffer;
956 }
957
958 // Prints one-line description of a signal set.
959 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
960 char buf[NUM_IMPORTANT_SIGS + 1];
961 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
962 st->print("%s", buf);
963 }
964
965 // Writes one-line description of a combination of sigaction.sa_flags into a user
966 // provided buffer. Returns that buffer.
967 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
968 char* p = buffer;
969 size_t remaining = size;
970 bool first = true;
971 int idx = 0;
972
973 assert(buffer, "invalid argument");
974
975 if (size == 0) {
976 return buffer;
977 }
978
979 strncpy(buffer, "none", size);
980
981 const struct {
982 // NB: i is an unsigned int here because SA_RESETHAND is on some
983 // systems 0x80000000, which is implicitly unsigned. Assignining
984 // it to an int field would be an overflow in unsigned-to-signed
985 // conversion.
986 unsigned int i;
987 const char* s;
988 } flaginfo [] = {
989 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
990 { SA_ONSTACK, "SA_ONSTACK" },
991 { SA_RESETHAND, "SA_RESETHAND" },
992 { SA_RESTART, "SA_RESTART" },
993 { SA_SIGINFO, "SA_SIGINFO" },
994 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
995 { SA_NODEFER, "SA_NODEFER" },
996 #ifdef AIX
997 { SA_ONSTACK, "SA_ONSTACK" },
998 { SA_OLDSTYLE, "SA_OLDSTYLE" },
999 #endif
1000 { 0, NULL }
1001 };
1002
1003 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
1004 if (flags & flaginfo[idx].i) {
1005 if (first) {
1006 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
1007 first = false;
1008 } else {
1009 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
1010 }
1011 const size_t len = strlen(p);
1012 p += len;
1013 remaining -= len;
1014 }
1015 }
1016
1017 buffer[size - 1] = '\0';
1018
1019 return buffer;
1020 }
1021
1022 // Prints one-line description of a combination of sigaction.sa_flags.
1023 void os::Posix::print_sa_flags(outputStream* st, int flags) {
1024 char buffer[0x100];
1025 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
1026 st->print("%s", buffer);
1027 }
1028
1029 // Helper function for os::Posix::print_siginfo_...():
1030 // return a textual description for signal code.
1031 struct enum_sigcode_desc_t {
1032 const char* s_name;
1033 const char* s_desc;
1034 };
1035
1036 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
1037
1038 const struct {
1039 int sig; int code; const char* s_code; const char* s_desc;
1040 } t1 [] = {
1041 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
1042 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
1043 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
1044 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
1045 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
1046 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
1047 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
1048 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
1049 #if defined(IA64) && defined(LINUX)
1050 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
1051 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
1052 #endif
1053 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
1054 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
1055 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
1056 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
1057 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
1058 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
1059 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
1060 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
1061 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
1062 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
1063 #ifdef AIX
1064 // no explanation found what keyerr would be
1065 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
1066 #endif
1067 #if defined(IA64) && !defined(AIX)
1068 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
1069 #endif
1070 #if defined(__sparc) && defined(SOLARIS)
1071 // define Solaris Sparc M7 ADI SEGV signals
1072 #if !defined(SEGV_ACCADI)
1073 #define SEGV_ACCADI 3
1074 #endif
1075 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
1076 #if !defined(SEGV_ACCDERR)
1077 #define SEGV_ACCDERR 4
1078 #endif
1079 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
1080 #if !defined(SEGV_ACCPERR)
1081 #define SEGV_ACCPERR 5
1082 #endif
1083 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
1084 #endif // defined(__sparc) && defined(SOLARIS)
1085 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
1086 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
1087 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
1088 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
1089 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
1090 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
1091 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
1092 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
1093 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
1094 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
1095 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
1096 #ifdef SIGPOLL
1097 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
1098 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
1099 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
1100 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
1101 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
1102 #endif
1103 { -1, -1, NULL, NULL }
1104 };
1105
1106 // Codes valid in any signal context.
1107 const struct {
1108 int code; const char* s_code; const char* s_desc;
1109 } t2 [] = {
1110 { SI_USER, "SI_USER", "Signal sent by kill()." },
1111 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
1112 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
1113 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
1114 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
1115 // Linux specific
1116 #ifdef SI_TKILL
1117 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
1118 #endif
1119 #ifdef SI_DETHREAD
1120 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
1121 #endif
1122 #ifdef SI_KERNEL
1123 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
1124 #endif
1125 #ifdef SI_SIGIO
1126 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
1127 #endif
1128
1129 #ifdef AIX
1130 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
1131 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
1132 #endif
1133
1134 #ifdef __sun
1135 { SI_NOINFO, "SI_NOINFO", "No signal information" },
1136 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
1137 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
1138 #endif
1139
1140 { -1, NULL, NULL }
1141 };
1142
1143 const char* s_code = NULL;
1144 const char* s_desc = NULL;
1145
1146 for (int i = 0; t1[i].sig != -1; i ++) {
1147 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
1148 s_code = t1[i].s_code;
1149 s_desc = t1[i].s_desc;
1150 break;
1151 }
1152 }
1153
1154 if (s_code == NULL) {
1155 for (int i = 0; t2[i].s_code != NULL; i ++) {
1156 if (t2[i].code == si->si_code) {
1157 s_code = t2[i].s_code;
1158 s_desc = t2[i].s_desc;
1159 }
1160 }
1161 }
1162
1163 if (s_code == NULL) {
1164 out->s_name = "unknown";
1165 out->s_desc = "unknown";
1166 return false;
1167 }
1168
1169 out->s_name = s_code;
1170 out->s_desc = s_desc;
1171
1172 return true;
1173 }
1174
1175 void os::print_siginfo(outputStream* os, const void* si0) {
1176
1177 const siginfo_t* const si = (const siginfo_t*) si0;
1178
1179 char buf[20];
1180 os->print("siginfo:");
1181
1182 if (!si) {
1183 os->print(" <null>");
1184 return;
1185 }
1186
1187 const int sig = si->si_signo;
1188
1189 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1190
1191 enum_sigcode_desc_t ed;
1192 get_signal_code_description(si, &ed);
1193 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1194
1195 if (si->si_errno) {
1196 os->print(", si_errno: %d", si->si_errno);
1197 }
1198
1199 // Output additional information depending on the signal code.
1200
1201 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1202 // so it depends on the context which member to use. For synchronous error signals,
1203 // we print si_addr, unless the signal was sent by another process or thread, in
1204 // which case we print out pid or tid of the sender.
1205 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1206 const pid_t pid = si->si_pid;
1207 os->print(", si_pid: %ld", (long) pid);
1208 if (IS_VALID_PID(pid)) {
1209 const pid_t me = getpid();
1210 if (me == pid) {
1211 os->print(" (current process)");
1212 }
1213 } else {
1214 os->print(" (invalid)");
1215 }
1216 os->print(", si_uid: %ld", (long) si->si_uid);
1217 if (sig == SIGCHLD) {
1218 os->print(", si_status: %d", si->si_status);
1219 }
1220 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1221 sig == SIGTRAP || sig == SIGFPE) {
1222 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1223 #ifdef SIGPOLL
1224 } else if (sig == SIGPOLL) {
1225 os->print(", si_band: %ld", si->si_band);
1226 #endif
1227 }
1228
1229 }
1230
1231 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1232 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1233 }
1234
1235 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1236 #if defined(AIX)
1237 return Aix::ucontext_get_pc(ctx);
1238 #elif defined(BSD)
1239 return Bsd::ucontext_get_pc(ctx);
1240 #elif defined(LINUX)
1241 return Linux::ucontext_get_pc(ctx);
1242 #elif defined(SOLARIS)
1243 return Solaris::ucontext_get_pc(ctx);
1244 #else
1245 VMError::report_and_die("unimplemented ucontext_get_pc");
1246 #endif
1247 }
1248
1249 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1250 #if defined(AIX)
1251 Aix::ucontext_set_pc(ctx, pc);
1252 #elif defined(BSD)
1253 Bsd::ucontext_set_pc(ctx, pc);
1254 #elif defined(LINUX)
1255 Linux::ucontext_set_pc(ctx, pc);
1256 #elif defined(SOLARIS)
1257 Solaris::ucontext_set_pc(ctx, pc);
1258 #else
1259 VMError::report_and_die("unimplemented ucontext_get_pc");
1260 #endif
1261 }
1262
1263 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1264 size_t stack_size = 0;
1265 size_t guard_size = 0;
1266 int detachstate = 0;
1267 pthread_attr_getstacksize(attr, &stack_size);
1268 pthread_attr_getguardsize(attr, &guard_size);
1269 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1270 LINUX_ONLY(stack_size -= guard_size);
1271 pthread_attr_getdetachstate(attr, &detachstate);
1272 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1273 stack_size / 1024, guard_size / 1024,
1274 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1275 return buf;
1276 }
1277
1278 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1279
1280 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1281 assert(false, "os::Posix::realpath: invalid arguments.");
1282 errno = EINVAL;
1283 return NULL;
1284 }
1285
1286 char* result = NULL;
1287
1288 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1289 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1290 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1291 char* p = ::realpath(filename, NULL);
1292 if (p != NULL) {
1293 if (strlen(p) < outbuflen) {
1294 strcpy(outbuf, p);
1295 result = outbuf;
1296 } else {
1297 errno = ENAMETOOLONG;
1298 }
1299 ::free(p); // *not* os::free
1300 } else {
1301 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1302 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1303 // that it complains about the NULL we handed down as user buffer.
1304 // In this case, use the user provided buffer but at least check whether realpath caused
1305 // a memory overwrite.
1306 if (errno == EINVAL) {
1307 outbuf[outbuflen - 1] = '\0';
1308 p = ::realpath(filename, outbuf);
1309 if (p != NULL) {
1310 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1311 result = p;
1312 }
1313 }
1314 }
1315 return result;
1316
1317 }
1318
1319
1320 // Check minimum allowable stack sizes for thread creation and to initialize
1321 // the java system classes, including StackOverflowError - depends on page
1322 // size.
1323 // The space needed for frames during startup is platform dependent. It
1324 // depends on word size, platform calling conventions, C frame layout and
1325 // interpreter/C1/C2 design decisions. Therefore this is given in a
1326 // platform (os/cpu) dependent constant.
1327 // To this, space for guard mechanisms is added, which depends on the
1328 // page size which again depends on the concrete system the VM is running
1329 // on. Space for libc guard pages is not included in this size.
1330 jint os::Posix::set_minimum_stack_sizes() {
1331 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1332
1333 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1334 JavaThread::stack_guard_zone_size() +
1335 JavaThread::stack_shadow_zone_size();
1336
1337 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1338 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1339
1340 size_t stack_size_in_bytes = ThreadStackSize * K;
1341 if (stack_size_in_bytes != 0 &&
1342 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1343 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1344 // ThreadStackSize so we go with "Java thread stack size" instead
1345 // of "ThreadStackSize" to be more friendly.
1346 tty->print_cr("\nThe Java thread stack size specified is too small. "
1347 "Specify at least " SIZE_FORMAT "k",
1348 _java_thread_min_stack_allowed / K);
1349 return JNI_ERR;
1350 }
1351
1352 // Make the stack size a multiple of the page size so that
1353 // the yellow/red zones can be guarded.
1354 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1355
1356 // Reminder: a compiler thread is a Java thread.
1357 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1358 JavaThread::stack_guard_zone_size() +
1359 JavaThread::stack_shadow_zone_size();
1360
1361 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1362 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1363
1364 stack_size_in_bytes = CompilerThreadStackSize * K;
1365 if (stack_size_in_bytes != 0 &&
1366 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1367 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1368 "Specify at least " SIZE_FORMAT "k",
1369 _compiler_thread_min_stack_allowed / K);
1370 return JNI_ERR;
1371 }
1372
1373 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1374 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1375
1376 stack_size_in_bytes = VMThreadStackSize * K;
1377 if (stack_size_in_bytes != 0 &&
1378 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1379 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1380 "Specify at least " SIZE_FORMAT "k",
1381 _vm_internal_thread_min_stack_allowed / K);
1382 return JNI_ERR;
1383 }
1384 return JNI_OK;
1385 }
1386
1387 // Called when creating the thread. The minimum stack sizes have already been calculated
1388 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1389 size_t stack_size;
1390 if (req_stack_size == 0) {
1391 stack_size = default_stack_size(thr_type);
1392 } else {
1393 stack_size = req_stack_size;
1394 }
1395
1396 switch (thr_type) {
1397 case os::java_thread:
1398 // Java threads use ThreadStackSize which default value can be
1399 // changed with the flag -Xss
1400 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1401 // no requested size and we have a more specific default value
1402 stack_size = JavaThread::stack_size_at_create();
1403 }
1404 stack_size = MAX2(stack_size,
1405 _java_thread_min_stack_allowed);
1406 break;
1407 case os::compiler_thread:
1408 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1409 // no requested size and we have a more specific default value
1410 stack_size = (size_t)(CompilerThreadStackSize * K);
1411 }
1412 stack_size = MAX2(stack_size,
1413 _compiler_thread_min_stack_allowed);
1414 break;
1415 case os::vm_thread:
1416 case os::pgc_thread:
1417 case os::cgc_thread:
1418 case os::watcher_thread:
1419 default: // presume the unknown thr_type is a VM internal
1420 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1421 // no requested size and we have a more specific default value
1422 stack_size = (size_t)(VMThreadStackSize * K);
1423 }
1424
1425 stack_size = MAX2(stack_size,
1426 _vm_internal_thread_min_stack_allowed);
1427 break;
1428 }
1429
1430 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1431 // Be careful not to round up to 0. Align down in that case.
1432 if (stack_size <= SIZE_MAX - vm_page_size()) {
1433 stack_size = align_up(stack_size, vm_page_size());
1434 } else {
1435 stack_size = align_down(stack_size, vm_page_size());
1436 }
1437
1438 return stack_size;
1439 }
1440
1441 Thread* os::ThreadCrashProtection::_protected_thread = NULL;
1442 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL;
1443 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0;
1444
1445 os::ThreadCrashProtection::ThreadCrashProtection() {
1446 }
1447
1448 /*
1449 * See the caveats for this class in os_posix.hpp
1450 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1451 * method and returns false. If none of the signals are raised, returns true.
1452 * The callback is supposed to provide the method that should be protected.
1453 */
1454 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1455 sigset_t saved_sig_mask;
1456
1457 Thread::muxAcquire(&_crash_mux, "CrashProtection");
1458
1459 _protected_thread = Thread::current_or_null();
1460 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread");
1461
1462 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1463 // since on at least some systems (OS X) siglongjmp will restore the mask
1464 // for the process, not the thread
1465 pthread_sigmask(0, NULL, &saved_sig_mask);
1466 if (sigsetjmp(_jmpbuf, 0) == 0) {
1467 // make sure we can see in the signal handler that we have crash protection
1468 // installed
1469 _crash_protection = this;
1470 cb.call();
1471 // and clear the crash protection
1472 _crash_protection = NULL;
1473 _protected_thread = NULL;
1474 Thread::muxRelease(&_crash_mux);
1475 return true;
1476 }
1477 // this happens when we siglongjmp() back
1478 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1479 _crash_protection = NULL;
1480 _protected_thread = NULL;
1481 Thread::muxRelease(&_crash_mux);
1482 return false;
1483 }
1484
1485 void os::ThreadCrashProtection::restore() {
1486 assert(_crash_protection != NULL, "must have crash protection");
1487 siglongjmp(_jmpbuf, 1);
1488 }
1489
1490 void os::ThreadCrashProtection::check_crash_protection(int sig,
1491 Thread* thread) {
1492
1493 if (thread != NULL &&
1494 thread == _protected_thread &&
1495 _crash_protection != NULL) {
1496
1497 if (sig == SIGSEGV || sig == SIGBUS) {
1498 _crash_protection->restore();
1499 }
1500 }
1501 }
1502
1503 // POSIX unamed semaphores are not supported on OS X.
1504 #ifndef __APPLE__
1505
1506 PosixSemaphore::PosixSemaphore(uint value) {
1507 int ret = sem_init(&_semaphore, 0, value);
1508
1509 guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
1510 }
1511
1512 PosixSemaphore::~PosixSemaphore() {
1513 sem_destroy(&_semaphore);
1514 }
1515
1516 void PosixSemaphore::signal(uint count) {
1517 for (uint i = 0; i < count; i++) {
1518 int ret = sem_post(&_semaphore);
1519
1520 assert_with_errno(ret == 0, "sem_post failed");
1521 }
1522 }
1523
1524 void PosixSemaphore::wait() {
1525 int ret;
1526
1527 do {
1528 ret = sem_wait(&_semaphore);
1529 } while (ret != 0 && errno == EINTR);
1530
1531 assert_with_errno(ret == 0, "sem_wait failed");
1532 }
1533
1534 bool PosixSemaphore::trywait() {
1535 int ret;
1536
1537 do {
1538 ret = sem_trywait(&_semaphore);
1539 } while (ret != 0 && errno == EINTR);
1540
1541 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
1542
1543 return ret == 0;
1544 }
1545
1546 bool PosixSemaphore::timedwait(struct timespec ts) {
1547 while (true) {
1548 int result = sem_timedwait(&_semaphore, &ts);
1549 if (result == 0) {
1550 return true;
1551 } else if (errno == EINTR) {
1552 continue;
1553 } else if (errno == ETIMEDOUT) {
1554 return false;
1555 } else {
1556 assert_with_errno(false, "timedwait failed");
1557 return false;
1558 }
1559 }
1560 }
1561
1562 #endif // __APPLE__
1563
1564
1565 // Shared pthread_mutex/cond based PlatformEvent implementation.
1566 // Not currently usable by Solaris.
1567
1568 #ifndef SOLARIS
1569
1570 // Shared condattr object for use with relative timed-waits. Will be associated
1571 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1572 // but otherwise whatever default is used by the platform - generally the
1573 // time-of-day clock.
1574 static pthread_condattr_t _condAttr[1];
1575
1576 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1577 // all systems (e.g. FreeBSD) map the default to "normal".
1578 static pthread_mutexattr_t _mutexAttr[1];
1579
1580 // common basic initialization that is always supported
1581 static void pthread_init_common(void) {
1582 int status;
1583 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1584 fatal("pthread_condattr_init: %s", os::strerror(status));
1585 }
1586 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1587 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1588 }
1589 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1590 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1591 }
1592 }
1593
1594 // Not all POSIX types and API's are available on all notionally "posix"
1595 // platforms. If we have build-time support then we will check for actual
1596 // runtime support via dlopen/dlsym lookup. This allows for running on an
1597 // older OS version compared to the build platform. But if there is no
1598 // build time support then there cannot be any runtime support as we do not
1599 // know what the runtime types would be (for example clockid_t might be an
1600 // int or int64_t).
1601 //
1602 #ifdef SUPPORTS_CLOCK_MONOTONIC
1603
1604 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1605
1606 static int (*_clock_gettime)(clockid_t, struct timespec *);
1607 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1608
1609 static bool _use_clock_monotonic_condattr;
1610
1611 // Determine what POSIX API's are present and do appropriate
1612 // configuration.
1613 void os::Posix::init(void) {
1614
1615 // NOTE: no logging available when this is called. Put logging
1616 // statements in init_2().
1617
1618 // Copied from os::Linux::clock_init(). The duplication is temporary.
1619
1620 // 1. Check for CLOCK_MONOTONIC support.
1621
1622 void* handle = NULL;
1623
1624 // For linux we need librt, for other OS we can find
1625 // this function in regular libc.
1626 #ifdef NEEDS_LIBRT
1627 // We do dlopen's in this particular order due to bug in linux
1628 // dynamic loader (see 6348968) leading to crash on exit.
1629 handle = dlopen("librt.so.1", RTLD_LAZY);
1630 if (handle == NULL) {
1631 handle = dlopen("librt.so", RTLD_LAZY);
1632 }
1633 #endif
1634
1635 if (handle == NULL) {
1636 handle = RTLD_DEFAULT;
1637 }
1638
1639 _clock_gettime = NULL;
1640
1641 int (*clock_getres_func)(clockid_t, struct timespec*) =
1642 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1643 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1644 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1645 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1646 // We assume that if both clock_gettime and clock_getres support
1647 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1648 struct timespec res;
1649 struct timespec tp;
1650 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1651 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1652 // Yes, monotonic clock is supported.
1653 _clock_gettime = clock_gettime_func;
1654 } else {
1655 #ifdef NEEDS_LIBRT
1656 // Close librt if there is no monotonic clock.
1657 if (handle != RTLD_DEFAULT) {
1658 dlclose(handle);
1659 }
1660 #endif
1661 }
1662 }
1663
1664 // 2. Check for pthread_condattr_setclock support.
1665
1666 _pthread_condattr_setclock = NULL;
1667
1668 // libpthread is already loaded.
1669 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1670 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1671 "pthread_condattr_setclock");
1672 if (condattr_setclock_func != NULL) {
1673 _pthread_condattr_setclock = condattr_setclock_func;
1674 }
1675
1676 // Now do general initialization.
1677
1678 pthread_init_common();
1679
1680 int status;
1681 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1682 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1683 if (status == EINVAL) {
1684 _use_clock_monotonic_condattr = false;
1685 warning("Unable to use monotonic clock with relative timed-waits" \
1686 " - changes to the time-of-day clock may have adverse affects");
1687 } else {
1688 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1689 }
1690 } else {
1691 _use_clock_monotonic_condattr = true;
1692 }
1693 } else {
1694 _use_clock_monotonic_condattr = false;
1695 }
1696 }
1697
1698 void os::Posix::init_2(void) {
1699 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1700 (_clock_gettime != NULL ? "" : " not"));
1701 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1702 (_pthread_condattr_setclock != NULL ? "" : " not"));
1703 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1704 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1705 }
1706
1707 #else // !SUPPORTS_CLOCK_MONOTONIC
1708
1709 void os::Posix::init(void) {
1710 pthread_init_common();
1711 }
1712
1713 void os::Posix::init_2(void) {
1714 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1715 log_info(os)("Use of pthread_condattr_setclock is not supported");
1716 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1717 }
1718
1719 #endif // SUPPORTS_CLOCK_MONOTONIC
1720
1721 os::PlatformEvent::PlatformEvent() {
1722 int status = pthread_cond_init(_cond, _condAttr);
1723 assert_status(status == 0, status, "cond_init");
1724 status = pthread_mutex_init(_mutex, _mutexAttr);
1725 assert_status(status == 0, status, "mutex_init");
1726 _event = 0;
1727 _nParked = 0;
1728 }
1729
1730 // Utility to convert the given timeout to an absolute timespec
1731 // (based on the appropriate clock) to use with pthread_cond_timewait.
1732 // The clock queried here must be the clock used to manage the
1733 // timeout of the condition variable.
1734 //
1735 // The passed in timeout value is either a relative time in nanoseconds
1736 // or an absolute time in milliseconds. A relative timeout will be
1737 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1738 // the default time-of-day clock will be used.
1739
1740 // Given time is a 64-bit value and the time_t used in the timespec is
1741 // sometimes a signed-32-bit value we have to watch for overflow if times
1742 // way in the future are given. Further on Solaris versions
1743 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1744 // number of seconds, in abstime, is less than current_time + 100000000.
1745 // As it will be over 20 years before "now + 100000000" will overflow we can
1746 // ignore overflow and just impose a hard-limit on seconds using the value
1747 // of "now + 100000000". This places a limit on the timeout of about 3.17
1748 // years from "now".
1749 //
1750 #define MAX_SECS 100000000
1751
1752 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1753 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1754 // on which clock is being used).
1755 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1756 jlong now_part_sec, jlong unit) {
1757 time_t max_secs = now_sec + MAX_SECS;
1758
1759 jlong seconds = timeout / NANOUNITS;
1760 timeout %= NANOUNITS; // remaining nanos
1761
1762 if (seconds >= MAX_SECS) {
1763 // More seconds than we can add, so pin to max_secs.
1764 abstime->tv_sec = max_secs;
1765 abstime->tv_nsec = 0;
1766 } else {
1767 abstime->tv_sec = now_sec + seconds;
1768 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1769 if (nanos >= NANOUNITS) { // overflow
1770 abstime->tv_sec += 1;
1771 nanos -= NANOUNITS;
1772 }
1773 abstime->tv_nsec = nanos;
1774 }
1775 }
1776
1777 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1778 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1779 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1780 time_t max_secs = now_sec + MAX_SECS;
1781
1782 jlong seconds = deadline / MILLIUNITS;
1783 jlong millis = deadline % MILLIUNITS;
1784
1785 if (seconds >= max_secs) {
1786 // Absolute seconds exceeds allowed max, so pin to max_secs.
1787 abstime->tv_sec = max_secs;
1788 abstime->tv_nsec = 0;
1789 } else {
1790 abstime->tv_sec = seconds;
1791 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1792 }
1793 }
1794
1795 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1796 DEBUG_ONLY(int max_secs = MAX_SECS;)
1797
1798 if (timeout < 0) {
1799 timeout = 0;
1800 }
1801
1802 #ifdef SUPPORTS_CLOCK_MONOTONIC
1803
1804 if (_use_clock_monotonic_condattr && !isAbsolute) {
1805 struct timespec now;
1806 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1807 assert_status(status == 0, status, "clock_gettime");
1808 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1809 DEBUG_ONLY(max_secs += now.tv_sec;)
1810 } else {
1811
1812 #else
1813
1814 { // Match the block scope.
1815
1816 #endif // SUPPORTS_CLOCK_MONOTONIC
1817
1818 // Time-of-day clock is all we can reliably use.
1819 struct timeval now;
1820 int status = gettimeofday(&now, NULL);
1821 assert_status(status == 0, errno, "gettimeofday");
1822 if (isAbsolute) {
1823 unpack_abs_time(abstime, timeout, now.tv_sec);
1824 } else {
1825 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1826 }
1827 DEBUG_ONLY(max_secs += now.tv_sec;)
1828 }
1829
1830 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1831 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1832 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1833 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1834 }
1835
1836 // PlatformEvent
1837 //
1838 // Assumption:
1839 // Only one parker can exist on an event, which is why we allocate
1840 // them per-thread. Multiple unparkers can coexist.
1841 //
1842 // _event serves as a restricted-range semaphore.
1843 // -1 : thread is blocked, i.e. there is a waiter
1844 // 0 : neutral: thread is running or ready,
1845 // could have been signaled after a wait started
1846 // 1 : signaled - thread is running or ready
1847 //
1848 // Having three states allows for some detection of bad usage - see
1849 // comments on unpark().
1850
1851 void os::PlatformEvent::park() { // AKA "down()"
1852 // Transitions for _event:
1853 // -1 => -1 : illegal
1854 // 1 => 0 : pass - return immediately
1855 // 0 => -1 : block; then set _event to 0 before returning
1856
1857 // Invariant: Only the thread associated with the PlatformEvent
1858 // may call park().
1859 assert(_nParked == 0, "invariant");
1860
1861 int v;
1862
1863 // atomically decrement _event
1864 for (;;) {
1865 v = _event;
1866 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1867 }
1868 guarantee(v >= 0, "invariant");
1869
1870 if (v == 0) { // Do this the hard way by blocking ...
1871 int status = pthread_mutex_lock(_mutex);
1872 assert_status(status == 0, status, "mutex_lock");
1873 guarantee(_nParked == 0, "invariant");
1874 ++_nParked;
1875 while (_event < 0) {
1876 // OS-level "spurious wakeups" are ignored
1877 status = pthread_cond_wait(_cond, _mutex);
1878 assert_status(status == 0, status, "cond_wait");
1879 }
1880 --_nParked;
1881
1882 _event = 0;
1883 status = pthread_mutex_unlock(_mutex);
1884 assert_status(status == 0, status, "mutex_unlock");
1885 // Paranoia to ensure our locked and lock-free paths interact
1886 // correctly with each other.
1887 OrderAccess::fence();
1888 }
1889 guarantee(_event >= 0, "invariant");
1890 }
1891
1892 int os::PlatformEvent::park(jlong millis) {
1893 // Transitions for _event:
1894 // -1 => -1 : illegal
1895 // 1 => 0 : pass - return immediately
1896 // 0 => -1 : block; then set _event to 0 before returning
1897
1898 // Invariant: Only the thread associated with the Event/PlatformEvent
1899 // may call park().
1900 assert(_nParked == 0, "invariant");
1901
1902 int v;
1903 // atomically decrement _event
1904 for (;;) {
1905 v = _event;
1906 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1907 }
1908 guarantee(v >= 0, "invariant");
1909
1910 if (v == 0) { // Do this the hard way by blocking ...
1911 struct timespec abst;
1912 // We have to watch for overflow when converting millis to nanos,
1913 // but if millis is that large then we will end up limiting to
1914 // MAX_SECS anyway, so just do that here.
1915 if (millis / MILLIUNITS > MAX_SECS) {
1916 millis = jlong(MAX_SECS) * MILLIUNITS;
1917 }
1918 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1919
1920 int ret = OS_TIMEOUT;
1921 int status = pthread_mutex_lock(_mutex);
1922 assert_status(status == 0, status, "mutex_lock");
1923 guarantee(_nParked == 0, "invariant");
1924 ++_nParked;
1925
1926 while (_event < 0) {
1927 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1928 assert_status(status == 0 || status == ETIMEDOUT,
1929 status, "cond_timedwait");
1930 // OS-level "spurious wakeups" are ignored unless the archaic
1931 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1932 if (!FilterSpuriousWakeups) break;
1933 if (status == ETIMEDOUT) break;
1934 }
1935 --_nParked;
1936
1937 if (_event >= 0) {
1938 ret = OS_OK;
1939 }
1940
1941 _event = 0;
1942 status = pthread_mutex_unlock(_mutex);
1943 assert_status(status == 0, status, "mutex_unlock");
1944 // Paranoia to ensure our locked and lock-free paths interact
1945 // correctly with each other.
1946 OrderAccess::fence();
1947 return ret;
1948 }
1949 return OS_OK;
1950 }
1951
1952 void os::PlatformEvent::unpark() {
1953 // Transitions for _event:
1954 // 0 => 1 : just return
1955 // 1 => 1 : just return
1956 // -1 => either 0 or 1; must signal target thread
1957 // That is, we can safely transition _event from -1 to either
1958 // 0 or 1.
1959 // See also: "Semaphores in Plan 9" by Mullender & Cox
1960 //
1961 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1962 // that it will take two back-to-back park() calls for the owning
1963 // thread to block. This has the benefit of forcing a spurious return
1964 // from the first park() call after an unpark() call which will help
1965 // shake out uses of park() and unpark() without checking state conditions
1966 // properly. This spurious return doesn't manifest itself in any user code
1967 // but only in the correctly written condition checking loops of ObjectMonitor,
1968 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1969
1970 if (Atomic::xchg(1, &_event) >= 0) return;
1971
1972 int status = pthread_mutex_lock(_mutex);
1973 assert_status(status == 0, status, "mutex_lock");
1974 int anyWaiters = _nParked;
1975 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1976 status = pthread_mutex_unlock(_mutex);
1977 assert_status(status == 0, status, "mutex_unlock");
1978
1979 // Note that we signal() *after* dropping the lock for "immortal" Events.
1980 // This is safe and avoids a common class of futile wakeups. In rare
1981 // circumstances this can cause a thread to return prematurely from
1982 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1983 // will simply re-test the condition and re-park itself.
1984 // This provides particular benefit if the underlying platform does not
1985 // provide wait morphing.
1986
1987 if (anyWaiters != 0) {
1988 status = pthread_cond_signal(_cond);
1989 assert_status(status == 0, status, "cond_signal");
1990 }
1991 }
1992
1993 // JSR166 support
1994
1995 os::PlatformParker::PlatformParker() {
1996 int status;
1997 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1998 assert_status(status == 0, status, "cond_init rel");
1999 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
2000 assert_status(status == 0, status, "cond_init abs");
2001 status = pthread_mutex_init(_mutex, _mutexAttr);
2002 assert_status(status == 0, status, "mutex_init");
2003 _cur_index = -1; // mark as unused
2004 }
2005
2006 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
2007 // sets count to 1 and signals condvar. Only one thread ever waits
2008 // on the condvar. Contention seen when trying to park implies that someone
2009 // is unparking you, so don't wait. And spurious returns are fine, so there
2010 // is no need to track notifications.
2011
2012 void Parker::park(bool isAbsolute, jlong time) {
2013
2014 // Optional fast-path check:
2015 // Return immediately if a permit is available.
2016 // We depend on Atomic::xchg() having full barrier semantics
2017 // since we are doing a lock-free update to _counter.
2018 if (Atomic::xchg(0, &_counter) > 0) return;
2019
2020 Thread* thread = Thread::current();
2021 assert(thread->is_Java_thread(), "Must be JavaThread");
2022 JavaThread *jt = (JavaThread *)thread;
2023
2024 // Optional optimization -- avoid state transitions if there's
2025 // an interrupt pending.
2026 if (Thread::is_interrupted(thread, false)) {
2027 return;
2028 }
2029
2030 // Next, demultiplex/decode time arguments
2031 struct timespec absTime;
2032 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
2033 return;
2034 }
2035 if (time > 0) {
2036 to_abstime(&absTime, time, isAbsolute);
2037 }
2038
2039 // Enter safepoint region
2040 // Beware of deadlocks such as 6317397.
2041 // The per-thread Parker:: mutex is a classic leaf-lock.
2042 // In particular a thread must never block on the Threads_lock while
2043 // holding the Parker:: mutex. If safepoints are pending both the
2044 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
2045 ThreadBlockInVM tbivm(jt);
2046
2047 // Don't wait if cannot get lock since interference arises from
2048 // unparking. Also re-check interrupt before trying wait.
2049 if (Thread::is_interrupted(thread, false) ||
2050 pthread_mutex_trylock(_mutex) != 0) {
2051 return;
2052 }
2053
2054 int status;
2055 if (_counter > 0) { // no wait needed
2056 _counter = 0;
2057 status = pthread_mutex_unlock(_mutex);
2058 assert_status(status == 0, status, "invariant");
2059 // Paranoia to ensure our locked and lock-free paths interact
2060 // correctly with each other and Java-level accesses.
2061 OrderAccess::fence();
2062 return;
2063 }
2064
2065 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2066 jt->set_suspend_equivalent();
2067 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2068
2069 assert(_cur_index == -1, "invariant");
2070 if (time == 0) {
2071 _cur_index = REL_INDEX; // arbitrary choice when not timed
2072 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
2073 assert_status(status == 0, status, "cond_timedwait");
2074 }
2075 else {
2076 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
2077 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
2078 assert_status(status == 0 || status == ETIMEDOUT,
2079 status, "cond_timedwait");
2080 }
2081 _cur_index = -1;
2082
2083 _counter = 0;
2084 status = pthread_mutex_unlock(_mutex);
2085 assert_status(status == 0, status, "invariant");
2086 // Paranoia to ensure our locked and lock-free paths interact
2087 // correctly with each other and Java-level accesses.
2088 OrderAccess::fence();
2089
2090 // If externally suspended while waiting, re-suspend
2091 if (jt->handle_special_suspend_equivalent_condition()) {
2092 jt->java_suspend_self();
2093 }
2094 }
2095
2096 void Parker::unpark() {
2097 int status = pthread_mutex_lock(_mutex);
2098 assert_status(status == 0, status, "invariant");
2099 const int s = _counter;
2100 _counter = 1;
2101 // must capture correct index before unlocking
2102 int index = _cur_index;
2103 status = pthread_mutex_unlock(_mutex);
2104 assert_status(status == 0, status, "invariant");
2105
2106 // Note that we signal() *after* dropping the lock for "immortal" Events.
2107 // This is safe and avoids a common class of futile wakeups. In rare
2108 // circumstances this can cause a thread to return prematurely from
2109 // cond_{timed}wait() but the spurious wakeup is benign and the victim
2110 // will simply re-test the condition and re-park itself.
2111 // This provides particular benefit if the underlying platform does not
2112 // provide wait morphing.
2113
2114 if (s < 1 && index != -1) {
2115 // thread is definitely parked
2116 status = pthread_cond_signal(&_cond[index]);
2117 assert_status(status == 0, status, "invariant");
2118 }
2119 }
2120
2121
2122 #endif // !SOLARIS