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 "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 }
300 else {
301 extra_base = os::reserve_memory(extra_size, NULL, alignment);
302 }
303
304 if (extra_base == NULL) {
305 return NULL;
306 }
307
308 // Do manual alignment
309 char* aligned_base = align_up(extra_base, alignment);
310
311 // [ | | ]
312 // ^ extra_base
313 // ^ extra_base + begin_offset == aligned_base
314 // extra_base + begin_offset + size ^
315 // extra_base + extra_size ^
316 // |<>| == begin_offset
317 // end_offset == |<>|
318 size_t begin_offset = aligned_base - extra_base;
319 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
320
321 if (begin_offset > 0) {
322 os::release_memory(extra_base, begin_offset);
323 }
324
325 if (end_offset > 0) {
326 os::release_memory(extra_base + begin_offset + size, end_offset);
327 }
328
329 if (file_desc != -1) {
330 // After we have an aligned address, we can replace anonymous mapping with file mapping
331 if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) {
332 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
333 }
334 MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC);
335 }
336 return aligned_base;
337 }
338
339 int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
340 return vsnprintf(buf, len, fmt, args);
341 }
342
343 int os::get_fileno(FILE* fp) {
344 return NOT_AIX(::)fileno(fp);
345 }
346
347 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
348 return gmtime_r(clock, res);
349 }
350
351 void os::Posix::print_load_average(outputStream* st) {
352 st->print("load average:");
353 double loadavg[3];
354 os::loadavg(loadavg, 3);
355 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
356 st->cr();
357 }
358
359 void os::Posix::print_rlimit_info(outputStream* st) {
360 st->print("rlimit:");
361 struct rlimit rlim;
362
363 st->print(" STACK ");
364 getrlimit(RLIMIT_STACK, &rlim);
365 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
366 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
367
368 st->print(", CORE ");
369 getrlimit(RLIMIT_CORE, &rlim);
370 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
371 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
372
373 // Isn't there on solaris
374 #if defined(AIX)
375 st->print(", NPROC ");
376 st->print("%d", sysconf(_SC_CHILD_MAX));
377 #elif !defined(SOLARIS)
378 st->print(", NPROC ");
379 getrlimit(RLIMIT_NPROC, &rlim);
380 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
381 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
382 #endif
383
384 st->print(", NOFILE ");
385 getrlimit(RLIMIT_NOFILE, &rlim);
386 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
387 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
388
389 st->print(", AS ");
390 getrlimit(RLIMIT_AS, &rlim);
391 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
392 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
393
394 st->print(", DATA ");
395 getrlimit(RLIMIT_DATA, &rlim);
396 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
397 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
398
399 st->print(", FSIZE ");
400 getrlimit(RLIMIT_FSIZE, &rlim);
401 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
402 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
403
404 st->cr();
405 }
406
407 void os::Posix::print_uname_info(outputStream* st) {
408 // kernel
409 st->print("uname:");
410 struct utsname name;
411 uname(&name);
412 st->print("%s ", name.sysname);
413 #ifdef ASSERT
414 st->print("%s ", name.nodename);
415 #endif
416 st->print("%s ", name.release);
417 st->print("%s ", name.version);
418 st->print("%s", name.machine);
419 st->cr();
420 }
421
422 bool os::get_host_name(char* buf, size_t buflen) {
423 struct utsname name;
424 uname(&name);
425 jio_snprintf(buf, buflen, "%s", name.nodename);
426 return true;
427 }
428
429 bool os::has_allocatable_memory_limit(julong* limit) {
430 struct rlimit rlim;
431 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
432 // if there was an error when calling getrlimit, assume that there is no limitation
433 // on virtual memory.
434 bool result;
435 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
436 result = false;
437 } else {
438 *limit = (julong)rlim.rlim_cur;
439 result = true;
440 }
441 #ifdef _LP64
442 return result;
443 #else
444 // arbitrary virtual space limit for 32 bit Unices found by testing. If
445 // getrlimit above returned a limit, bound it with this limit. Otherwise
446 // directly use it.
447 const julong max_virtual_limit = (julong)3800*M;
448 if (result) {
449 *limit = MIN2(*limit, max_virtual_limit);
450 } else {
451 *limit = max_virtual_limit;
452 }
453
454 // bound by actually allocatable memory. The algorithm uses two bounds, an
455 // upper and a lower limit. The upper limit is the current highest amount of
456 // memory that could not be allocated, the lower limit is the current highest
457 // amount of memory that could be allocated.
458 // The algorithm iteratively refines the result by halving the difference
459 // between these limits, updating either the upper limit (if that value could
460 // not be allocated) or the lower limit (if the that value could be allocated)
461 // until the difference between these limits is "small".
462
463 // the minimum amount of memory we care about allocating.
464 const julong min_allocation_size = M;
465
466 julong upper_limit = *limit;
467
468 // first check a few trivial cases
469 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
470 *limit = upper_limit;
471 } else if (!is_allocatable(min_allocation_size)) {
472 // we found that not even min_allocation_size is allocatable. Return it
473 // anyway. There is no point to search for a better value any more.
474 *limit = min_allocation_size;
475 } else {
476 // perform the binary search.
477 julong lower_limit = min_allocation_size;
478 while ((upper_limit - lower_limit) > min_allocation_size) {
479 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
480 temp_limit = align_down(temp_limit, min_allocation_size);
481 if (is_allocatable(temp_limit)) {
482 lower_limit = temp_limit;
483 } else {
484 upper_limit = temp_limit;
485 }
486 }
487 *limit = lower_limit;
488 }
489 return true;
490 #endif
491 }
492
493 const char* os::get_current_directory(char *buf, size_t buflen) {
494 return getcwd(buf, buflen);
495 }
496
497 FILE* os::open(int fd, const char* mode) {
498 return ::fdopen(fd, mode);
499 }
500
501 void os::flockfile(FILE* fp) {
502 ::flockfile(fp);
503 }
504
505 void os::funlockfile(FILE* fp) {
506 ::funlockfile(fp);
507 }
508
509 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
510 // which is used to find statically linked in agents.
511 // Parameters:
512 // sym_name: Symbol in library we are looking for
513 // lib_name: Name of library to look in, NULL for shared libs.
514 // is_absolute_path == true if lib_name is absolute path to agent
515 // such as "/a/b/libL.so"
516 // == false if only the base name of the library is passed in
517 // such as "L"
518 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
519 bool is_absolute_path) {
520 char *agent_entry_name;
521 size_t len;
522 size_t name_len;
523 size_t prefix_len = strlen(JNI_LIB_PREFIX);
524 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
525 const char *start;
526
527 if (lib_name != NULL) {
528 name_len = strlen(lib_name);
529 if (is_absolute_path) {
530 // Need to strip path, prefix and suffix
531 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
532 lib_name = ++start;
533 }
534 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
535 return NULL;
536 }
537 lib_name += prefix_len;
538 name_len = strlen(lib_name) - suffix_len;
539 }
540 }
541 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
542 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
543 if (agent_entry_name == NULL) {
544 return NULL;
545 }
546 strcpy(agent_entry_name, sym_name);
547 if (lib_name != NULL) {
548 strcat(agent_entry_name, "_");
549 strncat(agent_entry_name, lib_name, name_len);
550 }
551 return agent_entry_name;
552 }
553
554 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
555 assert(thread == Thread::current(), "thread consistency check");
556
557 ParkEvent * const slp = thread->_SleepEvent ;
558 slp->reset() ;
559 OrderAccess::fence() ;
560
561 if (interruptible) {
562 jlong prevtime = javaTimeNanos();
563
564 for (;;) {
565 if (os::is_interrupted(thread, true)) {
566 return OS_INTRPT;
567 }
568
569 jlong newtime = javaTimeNanos();
570
571 if (newtime - prevtime < 0) {
572 // time moving backwards, should only happen if no monotonic clock
573 // not a guarantee() because JVM should not abort on kernel/glibc bugs
574 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
575 } else {
576 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
577 }
578
579 if (millis <= 0) {
580 return OS_OK;
581 }
582
583 prevtime = newtime;
584
585 {
586 assert(thread->is_Java_thread(), "sanity check");
587 JavaThread *jt = (JavaThread *) thread;
588 ThreadBlockInVM tbivm(jt);
589 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
590
591 jt->set_suspend_equivalent();
592 // cleared by handle_special_suspend_equivalent_condition() or
593 // java_suspend_self() via check_and_wait_while_suspended()
594
595 slp->park(millis);
596
597 // were we externally suspended while we were waiting?
598 jt->check_and_wait_while_suspended();
599 }
600 }
601 } else {
602 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
603 jlong prevtime = javaTimeNanos();
604
605 for (;;) {
606 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
607 // the 1st iteration ...
608 jlong newtime = javaTimeNanos();
609
610 if (newtime - prevtime < 0) {
611 // time moving backwards, should only happen if no monotonic clock
612 // not a guarantee() because JVM should not abort on kernel/glibc bugs
613 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
614 } else {
615 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
616 }
617
618 if (millis <= 0) break ;
619
620 prevtime = newtime;
621 slp->park(millis);
622 }
623 return OS_OK ;
624 }
625 }
626
627 ////////////////////////////////////////////////////////////////////////////////
628 // interrupt support
629
630 void os::interrupt(Thread* thread) {
631 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
632 "possibility of dangling Thread pointer");
633
634 OSThread* osthread = thread->osthread();
635
636 if (!osthread->interrupted()) {
637 osthread->set_interrupted(true);
638 // More than one thread can get here with the same value of osthread,
639 // resulting in multiple notifications. We do, however, want the store
640 // to interrupted() to be visible to other threads before we execute unpark().
641 OrderAccess::fence();
642 ParkEvent * const slp = thread->_SleepEvent ;
643 if (slp != NULL) slp->unpark() ;
644 }
645
646 // For JSR166. Unpark even if interrupt status already was set
647 if (thread->is_Java_thread())
648 ((JavaThread*)thread)->parker()->unpark();
649
650 ParkEvent * ev = thread->_ParkEvent ;
651 if (ev != NULL) ev->unpark() ;
652
653 }
654
655 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
656 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
657 "possibility of dangling Thread pointer");
658
659 OSThread* osthread = thread->osthread();
660
661 bool interrupted = osthread->interrupted();
662
663 // NOTE that since there is no "lock" around the interrupt and
664 // is_interrupted operations, there is the possibility that the
665 // interrupted flag (in osThread) will be "false" but that the
666 // low-level events will be in the signaled state. This is
667 // intentional. The effect of this is that Object.wait() and
668 // LockSupport.park() will appear to have a spurious wakeup, which
669 // is allowed and not harmful, and the possibility is so rare that
670 // it is not worth the added complexity to add yet another lock.
671 // For the sleep event an explicit reset is performed on entry
672 // to os::sleep, so there is no early return. It has also been
673 // recommended not to put the interrupted flag into the "event"
674 // structure because it hides the issue.
675 if (interrupted && clear_interrupted) {
676 osthread->set_interrupted(false);
677 // consider thread->_SleepEvent->reset() ... optional optimization
678 }
679
680 return interrupted;
681 }
682
683
684
685 static const struct {
686 int sig; const char* name;
687 }
688 g_signal_info[] =
689 {
690 { SIGABRT, "SIGABRT" },
691 #ifdef SIGAIO
692 { SIGAIO, "SIGAIO" },
693 #endif
694 { SIGALRM, "SIGALRM" },
695 #ifdef SIGALRM1
696 { SIGALRM1, "SIGALRM1" },
697 #endif
698 { SIGBUS, "SIGBUS" },
699 #ifdef SIGCANCEL
700 { SIGCANCEL, "SIGCANCEL" },
701 #endif
702 { SIGCHLD, "SIGCHLD" },
703 #ifdef SIGCLD
704 { SIGCLD, "SIGCLD" },
705 #endif
706 { SIGCONT, "SIGCONT" },
707 #ifdef SIGCPUFAIL
708 { SIGCPUFAIL, "SIGCPUFAIL" },
709 #endif
710 #ifdef SIGDANGER
711 { SIGDANGER, "SIGDANGER" },
712 #endif
713 #ifdef SIGDIL
714 { SIGDIL, "SIGDIL" },
715 #endif
716 #ifdef SIGEMT
717 { SIGEMT, "SIGEMT" },
718 #endif
719 { SIGFPE, "SIGFPE" },
720 #ifdef SIGFREEZE
721 { SIGFREEZE, "SIGFREEZE" },
722 #endif
723 #ifdef SIGGFAULT
724 { SIGGFAULT, "SIGGFAULT" },
725 #endif
726 #ifdef SIGGRANT
727 { SIGGRANT, "SIGGRANT" },
728 #endif
729 { SIGHUP, "SIGHUP" },
730 { SIGILL, "SIGILL" },
731 { SIGINT, "SIGINT" },
732 #ifdef SIGIO
733 { SIGIO, "SIGIO" },
734 #endif
735 #ifdef SIGIOINT
736 { SIGIOINT, "SIGIOINT" },
737 #endif
738 #ifdef SIGIOT
739 // SIGIOT is there for BSD compatibility, but on most Unices just a
740 // synonym for SIGABRT. The result should be "SIGABRT", not
741 // "SIGIOT".
742 #if (SIGIOT != SIGABRT )
743 { SIGIOT, "SIGIOT" },
744 #endif
745 #endif
746 #ifdef SIGKAP
747 { SIGKAP, "SIGKAP" },
748 #endif
749 { SIGKILL, "SIGKILL" },
750 #ifdef SIGLOST
751 { SIGLOST, "SIGLOST" },
752 #endif
753 #ifdef SIGLWP
754 { SIGLWP, "SIGLWP" },
755 #endif
756 #ifdef SIGLWPTIMER
757 { SIGLWPTIMER, "SIGLWPTIMER" },
758 #endif
759 #ifdef SIGMIGRATE
760 { SIGMIGRATE, "SIGMIGRATE" },
761 #endif
762 #ifdef SIGMSG
763 { SIGMSG, "SIGMSG" },
764 #endif
765 { SIGPIPE, "SIGPIPE" },
766 #ifdef SIGPOLL
767 { SIGPOLL, "SIGPOLL" },
768 #endif
769 #ifdef SIGPRE
770 { SIGPRE, "SIGPRE" },
771 #endif
772 { SIGPROF, "SIGPROF" },
773 #ifdef SIGPTY
774 { SIGPTY, "SIGPTY" },
775 #endif
776 #ifdef SIGPWR
777 { SIGPWR, "SIGPWR" },
778 #endif
779 { SIGQUIT, "SIGQUIT" },
780 #ifdef SIGRECONFIG
781 { SIGRECONFIG, "SIGRECONFIG" },
782 #endif
783 #ifdef SIGRECOVERY
784 { SIGRECOVERY, "SIGRECOVERY" },
785 #endif
786 #ifdef SIGRESERVE
787 { SIGRESERVE, "SIGRESERVE" },
788 #endif
789 #ifdef SIGRETRACT
790 { SIGRETRACT, "SIGRETRACT" },
791 #endif
792 #ifdef SIGSAK
793 { SIGSAK, "SIGSAK" },
794 #endif
795 { SIGSEGV, "SIGSEGV" },
796 #ifdef SIGSOUND
797 { SIGSOUND, "SIGSOUND" },
798 #endif
799 #ifdef SIGSTKFLT
800 { SIGSTKFLT, "SIGSTKFLT" },
801 #endif
802 { SIGSTOP, "SIGSTOP" },
803 { SIGSYS, "SIGSYS" },
804 #ifdef SIGSYSERROR
805 { SIGSYSERROR, "SIGSYSERROR" },
806 #endif
807 #ifdef SIGTALRM
808 { SIGTALRM, "SIGTALRM" },
809 #endif
810 { SIGTERM, "SIGTERM" },
811 #ifdef SIGTHAW
812 { SIGTHAW, "SIGTHAW" },
813 #endif
814 { SIGTRAP, "SIGTRAP" },
815 #ifdef SIGTSTP
816 { SIGTSTP, "SIGTSTP" },
817 #endif
818 { SIGTTIN, "SIGTTIN" },
819 { SIGTTOU, "SIGTTOU" },
820 #ifdef SIGURG
821 { SIGURG, "SIGURG" },
822 #endif
823 { SIGUSR1, "SIGUSR1" },
824 { SIGUSR2, "SIGUSR2" },
825 #ifdef SIGVIRT
826 { SIGVIRT, "SIGVIRT" },
827 #endif
828 { SIGVTALRM, "SIGVTALRM" },
829 #ifdef SIGWAITING
830 { SIGWAITING, "SIGWAITING" },
831 #endif
832 #ifdef SIGWINCH
833 { SIGWINCH, "SIGWINCH" },
834 #endif
835 #ifdef SIGWINDOW
836 { SIGWINDOW, "SIGWINDOW" },
837 #endif
838 { SIGXCPU, "SIGXCPU" },
839 { SIGXFSZ, "SIGXFSZ" },
840 #ifdef SIGXRES
841 { SIGXRES, "SIGXRES" },
842 #endif
843 { -1, NULL }
844 };
845
846 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
847 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
848
849 const char* ret = NULL;
850
851 #ifdef SIGRTMIN
852 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
853 if (sig == SIGRTMIN) {
854 ret = "SIGRTMIN";
855 } else if (sig == SIGRTMAX) {
856 ret = "SIGRTMAX";
857 } else {
858 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
859 return out;
860 }
861 }
862 #endif
863
864 if (sig > 0) {
865 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
866 if (g_signal_info[idx].sig == sig) {
867 ret = g_signal_info[idx].name;
868 break;
869 }
870 }
871 }
872
873 if (!ret) {
874 if (!is_valid_signal(sig)) {
875 ret = "INVALID";
876 } else {
877 ret = "UNKNOWN";
878 }
879 }
880
881 if (out && outlen > 0) {
882 strncpy(out, ret, outlen);
883 out[outlen - 1] = '\0';
884 }
885 return out;
886 }
887
888 int os::Posix::get_signal_number(const char* signal_name) {
889 char tmp[30];
890 const char* s = signal_name;
891 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
892 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
893 s = tmp;
894 }
895 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
896 if (strcmp(g_signal_info[idx].name, s) == 0) {
897 return g_signal_info[idx].sig;
898 }
899 }
900 return -1;
901 }
902
903 int os::get_signal_number(const char* signal_name) {
904 return os::Posix::get_signal_number(signal_name);
905 }
906
907 // Returns true if signal number is valid.
908 bool os::Posix::is_valid_signal(int sig) {
909 // MacOS not really POSIX compliant: sigaddset does not return
910 // an error for invalid signal numbers. However, MacOS does not
911 // support real time signals and simply seems to have just 33
912 // signals with no holes in the signal range.
913 #ifdef __APPLE__
914 return sig >= 1 && sig < NSIG;
915 #else
916 // Use sigaddset to check for signal validity.
917 sigset_t set;
918 sigemptyset(&set);
919 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
920 return false;
921 }
922 return true;
923 #endif
924 }
925
926 // Returns:
927 // NULL for an invalid signal number
928 // "SIG<num>" for a valid but unknown signal number
929 // signal name otherwise.
930 const char* os::exception_name(int sig, char* buf, size_t size) {
931 if (!os::Posix::is_valid_signal(sig)) {
932 return NULL;
933 }
934 const char* const name = os::Posix::get_signal_name(sig, buf, size);
935 if (strcmp(name, "UNKNOWN") == 0) {
936 jio_snprintf(buf, size, "SIG%d", sig);
937 }
938 return buf;
939 }
940
941 #define NUM_IMPORTANT_SIGS 32
942 // Returns one-line short description of a signal set in a user provided buffer.
943 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
944 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
945 // Note: for shortness, just print out the first 32. That should
946 // cover most of the useful ones, apart from realtime signals.
947 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
948 const int rc = sigismember(set, sig);
949 if (rc == -1 && errno == EINVAL) {
950 buffer[sig-1] = '?';
951 } else {
952 buffer[sig-1] = rc == 0 ? '0' : '1';
953 }
954 }
955 buffer[NUM_IMPORTANT_SIGS] = 0;
956 return buffer;
957 }
958
959 // Prints one-line description of a signal set.
960 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
961 char buf[NUM_IMPORTANT_SIGS + 1];
962 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
963 st->print("%s", buf);
964 }
965
966 // Writes one-line description of a combination of sigaction.sa_flags into a user
967 // provided buffer. Returns that buffer.
968 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
969 char* p = buffer;
970 size_t remaining = size;
971 bool first = true;
972 int idx = 0;
973
974 assert(buffer, "invalid argument");
975
976 if (size == 0) {
977 return buffer;
978 }
979
980 strncpy(buffer, "none", size);
981
982 const struct {
983 // NB: i is an unsigned int here because SA_RESETHAND is on some
984 // systems 0x80000000, which is implicitly unsigned. Assignining
985 // it to an int field would be an overflow in unsigned-to-signed
986 // conversion.
987 unsigned int i;
988 const char* s;
989 } flaginfo [] = {
990 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
991 { SA_ONSTACK, "SA_ONSTACK" },
992 { SA_RESETHAND, "SA_RESETHAND" },
993 { SA_RESTART, "SA_RESTART" },
994 { SA_SIGINFO, "SA_SIGINFO" },
995 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
996 { SA_NODEFER, "SA_NODEFER" },
997 #ifdef AIX
998 { SA_ONSTACK, "SA_ONSTACK" },
999 { SA_OLDSTYLE, "SA_OLDSTYLE" },
1000 #endif
1001 { 0, NULL }
1002 };
1003
1004 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
1005 if (flags & flaginfo[idx].i) {
1006 if (first) {
1007 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
1008 first = false;
1009 } else {
1010 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
1011 }
1012 const size_t len = strlen(p);
1013 p += len;
1014 remaining -= len;
1015 }
1016 }
1017
1018 buffer[size - 1] = '\0';
1019
1020 return buffer;
1021 }
1022
1023 // Prints one-line description of a combination of sigaction.sa_flags.
1024 void os::Posix::print_sa_flags(outputStream* st, int flags) {
1025 char buffer[0x100];
1026 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
1027 st->print("%s", buffer);
1028 }
1029
1030 // Helper function for os::Posix::print_siginfo_...():
1031 // return a textual description for signal code.
1032 struct enum_sigcode_desc_t {
1033 const char* s_name;
1034 const char* s_desc;
1035 };
1036
1037 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
1038
1039 const struct {
1040 int sig; int code; const char* s_code; const char* s_desc;
1041 } t1 [] = {
1042 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
1043 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
1044 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
1045 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
1046 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
1047 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
1048 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
1049 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
1050 #if defined(IA64) && defined(LINUX)
1051 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
1052 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
1053 #endif
1054 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
1055 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
1056 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
1057 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
1058 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
1059 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
1060 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
1061 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
1062 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
1063 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
1064 #ifdef AIX
1065 // no explanation found what keyerr would be
1066 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
1067 #endif
1068 #if defined(IA64) && !defined(AIX)
1069 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
1070 #endif
1071 #if defined(__sparc) && defined(SOLARIS)
1072 // define Solaris Sparc M7 ADI SEGV signals
1073 #if !defined(SEGV_ACCADI)
1074 #define SEGV_ACCADI 3
1075 #endif
1076 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
1077 #if !defined(SEGV_ACCDERR)
1078 #define SEGV_ACCDERR 4
1079 #endif
1080 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
1081 #if !defined(SEGV_ACCPERR)
1082 #define SEGV_ACCPERR 5
1083 #endif
1084 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
1085 #endif // defined(__sparc) && defined(SOLARIS)
1086 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
1087 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
1088 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
1089 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
1090 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
1091 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
1092 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
1093 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
1094 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
1095 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
1096 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
1097 #ifdef SIGPOLL
1098 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
1099 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
1100 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
1101 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
1102 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
1103 #endif
1104 { -1, -1, NULL, NULL }
1105 };
1106
1107 // Codes valid in any signal context.
1108 const struct {
1109 int code; const char* s_code; const char* s_desc;
1110 } t2 [] = {
1111 { SI_USER, "SI_USER", "Signal sent by kill()." },
1112 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
1113 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
1114 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
1115 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
1116 // Linux specific
1117 #ifdef SI_TKILL
1118 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
1119 #endif
1120 #ifdef SI_DETHREAD
1121 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
1122 #endif
1123 #ifdef SI_KERNEL
1124 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
1125 #endif
1126 #ifdef SI_SIGIO
1127 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
1128 #endif
1129
1130 #ifdef AIX
1131 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
1132 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
1133 #endif
1134
1135 #ifdef __sun
1136 { SI_NOINFO, "SI_NOINFO", "No signal information" },
1137 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
1138 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
1139 #endif
1140
1141 { -1, NULL, NULL }
1142 };
1143
1144 const char* s_code = NULL;
1145 const char* s_desc = NULL;
1146
1147 for (int i = 0; t1[i].sig != -1; i ++) {
1148 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
1149 s_code = t1[i].s_code;
1150 s_desc = t1[i].s_desc;
1151 break;
1152 }
1153 }
1154
1155 if (s_code == NULL) {
1156 for (int i = 0; t2[i].s_code != NULL; i ++) {
1157 if (t2[i].code == si->si_code) {
1158 s_code = t2[i].s_code;
1159 s_desc = t2[i].s_desc;
1160 }
1161 }
1162 }
1163
1164 if (s_code == NULL) {
1165 out->s_name = "unknown";
1166 out->s_desc = "unknown";
1167 return false;
1168 }
1169
1170 out->s_name = s_code;
1171 out->s_desc = s_desc;
1172
1173 return true;
1174 }
1175
1176 void os::print_siginfo(outputStream* os, const void* si0) {
1177
1178 const siginfo_t* const si = (const siginfo_t*) si0;
1179
1180 char buf[20];
1181 os->print("siginfo:");
1182
1183 if (!si) {
1184 os->print(" <null>");
1185 return;
1186 }
1187
1188 const int sig = si->si_signo;
1189
1190 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1191
1192 enum_sigcode_desc_t ed;
1193 get_signal_code_description(si, &ed);
1194 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1195
1196 if (si->si_errno) {
1197 os->print(", si_errno: %d", si->si_errno);
1198 }
1199
1200 // Output additional information depending on the signal code.
1201
1202 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1203 // so it depends on the context which member to use. For synchronous error signals,
1204 // we print si_addr, unless the signal was sent by another process or thread, in
1205 // which case we print out pid or tid of the sender.
1206 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1207 const pid_t pid = si->si_pid;
1208 os->print(", si_pid: %ld", (long) pid);
1209 if (IS_VALID_PID(pid)) {
1210 const pid_t me = getpid();
1211 if (me == pid) {
1212 os->print(" (current process)");
1213 }
1214 } else {
1215 os->print(" (invalid)");
1216 }
1217 os->print(", si_uid: %ld", (long) si->si_uid);
1218 if (sig == SIGCHLD) {
1219 os->print(", si_status: %d", si->si_status);
1220 }
1221 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1222 sig == SIGTRAP || sig == SIGFPE) {
1223 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1224 #ifdef SIGPOLL
1225 } else if (sig == SIGPOLL) {
1226 os->print(", si_band: %ld", si->si_band);
1227 #endif
1228 }
1229
1230 }
1231
1232 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1233 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1234 }
1235
1236 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1237 #if defined(AIX)
1238 return Aix::ucontext_get_pc(ctx);
1239 #elif defined(BSD)
1240 return Bsd::ucontext_get_pc(ctx);
1241 #elif defined(LINUX)
1242 return Linux::ucontext_get_pc(ctx);
1243 #elif defined(SOLARIS)
1244 return Solaris::ucontext_get_pc(ctx);
1245 #else
1246 VMError::report_and_die("unimplemented ucontext_get_pc");
1247 #endif
1248 }
1249
1250 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1251 #if defined(AIX)
1252 Aix::ucontext_set_pc(ctx, pc);
1253 #elif defined(BSD)
1254 Bsd::ucontext_set_pc(ctx, pc);
1255 #elif defined(LINUX)
1256 Linux::ucontext_set_pc(ctx, pc);
1257 #elif defined(SOLARIS)
1258 Solaris::ucontext_set_pc(ctx, pc);
1259 #else
1260 VMError::report_and_die("unimplemented ucontext_get_pc");
1261 #endif
1262 }
1263
1264 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1265 size_t stack_size = 0;
1266 size_t guard_size = 0;
1267 int detachstate = 0;
1268 pthread_attr_getstacksize(attr, &stack_size);
1269 pthread_attr_getguardsize(attr, &guard_size);
1270 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1271 LINUX_ONLY(stack_size -= guard_size);
1272 pthread_attr_getdetachstate(attr, &detachstate);
1273 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1274 stack_size / 1024, guard_size / 1024,
1275 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1276 return buf;
1277 }
1278
1279 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1280
1281 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1282 assert(false, "os::Posix::realpath: invalid arguments.");
1283 errno = EINVAL;
1284 return NULL;
1285 }
1286
1287 char* result = NULL;
1288
1289 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1290 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1291 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1292 char* p = ::realpath(filename, NULL);
1293 if (p != NULL) {
1294 if (strlen(p) < outbuflen) {
1295 strcpy(outbuf, p);
1296 result = outbuf;
1297 } else {
1298 errno = ENAMETOOLONG;
1299 }
1300 ::free(p); // *not* os::free
1301 } else {
1302 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1303 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1304 // that it complains about the NULL we handed down as user buffer.
1305 // In this case, use the user provided buffer but at least check whether realpath caused
1306 // a memory overwrite.
1307 if (errno == EINVAL) {
1308 outbuf[outbuflen - 1] = '\0';
1309 p = ::realpath(filename, outbuf);
1310 if (p != NULL) {
1311 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1312 result = p;
1313 }
1314 }
1315 }
1316 return result;
1317
1318 }
1319
1320
1321 // Check minimum allowable stack sizes for thread creation and to initialize
1322 // the java system classes, including StackOverflowError - depends on page
1323 // size.
1324 // The space needed for frames during startup is platform dependent. It
1325 // depends on word size, platform calling conventions, C frame layout and
1326 // interpreter/C1/C2 design decisions. Therefore this is given in a
1327 // platform (os/cpu) dependent constant.
1328 // To this, space for guard mechanisms is added, which depends on the
1329 // page size which again depends on the concrete system the VM is running
1330 // on. Space for libc guard pages is not included in this size.
1331 jint os::Posix::set_minimum_stack_sizes() {
1332 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1333
1334 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1335 JavaThread::stack_guard_zone_size() +
1336 JavaThread::stack_shadow_zone_size();
1337
1338 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1339 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1340
1341 size_t stack_size_in_bytes = ThreadStackSize * K;
1342 if (stack_size_in_bytes != 0 &&
1343 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1344 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1345 // ThreadStackSize so we go with "Java thread stack size" instead
1346 // of "ThreadStackSize" to be more friendly.
1347 tty->print_cr("\nThe Java thread stack size specified is too small. "
1348 "Specify at least " SIZE_FORMAT "k",
1349 _java_thread_min_stack_allowed / K);
1350 return JNI_ERR;
1351 }
1352
1353 // Make the stack size a multiple of the page size so that
1354 // the yellow/red zones can be guarded.
1355 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1356
1357 // Reminder: a compiler thread is a Java thread.
1358 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1359 JavaThread::stack_guard_zone_size() +
1360 JavaThread::stack_shadow_zone_size();
1361
1362 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1363 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1364
1365 stack_size_in_bytes = CompilerThreadStackSize * K;
1366 if (stack_size_in_bytes != 0 &&
1367 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1368 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1369 "Specify at least " SIZE_FORMAT "k",
1370 _compiler_thread_min_stack_allowed / K);
1371 return JNI_ERR;
1372 }
1373
1374 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1375 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1376
1377 stack_size_in_bytes = VMThreadStackSize * K;
1378 if (stack_size_in_bytes != 0 &&
1379 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1380 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1381 "Specify at least " SIZE_FORMAT "k",
1382 _vm_internal_thread_min_stack_allowed / K);
1383 return JNI_ERR;
1384 }
1385 return JNI_OK;
1386 }
1387
1388 // Called when creating the thread. The minimum stack sizes have already been calculated
1389 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1390 size_t stack_size;
1391 if (req_stack_size == 0) {
1392 stack_size = default_stack_size(thr_type);
1393 } else {
1394 stack_size = req_stack_size;
1395 }
1396
1397 switch (thr_type) {
1398 case os::java_thread:
1399 // Java threads use ThreadStackSize which default value can be
1400 // changed with the flag -Xss
1401 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1402 // no requested size and we have a more specific default value
1403 stack_size = JavaThread::stack_size_at_create();
1404 }
1405 stack_size = MAX2(stack_size,
1406 _java_thread_min_stack_allowed);
1407 break;
1408 case os::compiler_thread:
1409 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1410 // no requested size and we have a more specific default value
1411 stack_size = (size_t)(CompilerThreadStackSize * K);
1412 }
1413 stack_size = MAX2(stack_size,
1414 _compiler_thread_min_stack_allowed);
1415 break;
1416 case os::vm_thread:
1417 case os::pgc_thread:
1418 case os::cgc_thread:
1419 case os::watcher_thread:
1420 default: // presume the unknown thr_type is a VM internal
1421 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1422 // no requested size and we have a more specific default value
1423 stack_size = (size_t)(VMThreadStackSize * K);
1424 }
1425
1426 stack_size = MAX2(stack_size,
1427 _vm_internal_thread_min_stack_allowed);
1428 break;
1429 }
1430
1431 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1432 // Be careful not to round up to 0. Align down in that case.
1433 if (stack_size <= SIZE_MAX - vm_page_size()) {
1434 stack_size = align_up(stack_size, vm_page_size());
1435 } else {
1436 stack_size = align_down(stack_size, vm_page_size());
1437 }
1438
1439 return stack_size;
1440 }
1441
1442 Thread* os::ThreadCrashProtection::_protected_thread = NULL;
1443 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL;
1444 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0;
1445
1446 os::ThreadCrashProtection::ThreadCrashProtection() {
1447 }
1448
1449 /*
1450 * See the caveats for this class in os_posix.hpp
1451 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1452 * method and returns false. If none of the signals are raised, returns true.
1453 * The callback is supposed to provide the method that should be protected.
1454 */
1455 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1456 sigset_t saved_sig_mask;
1457
1458 Thread::muxAcquire(&_crash_mux, "CrashProtection");
1459
1460 _protected_thread = Thread::current_or_null();
1461 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread");
1462
1463 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1464 // since on at least some systems (OS X) siglongjmp will restore the mask
1465 // for the process, not the thread
1466 pthread_sigmask(0, NULL, &saved_sig_mask);
1467 if (sigsetjmp(_jmpbuf, 0) == 0) {
1468 // make sure we can see in the signal handler that we have crash protection
1469 // installed
1470 _crash_protection = this;
1471 cb.call();
1472 // and clear the crash protection
1473 _crash_protection = NULL;
1474 _protected_thread = NULL;
1475 Thread::muxRelease(&_crash_mux);
1476 return true;
1477 }
1478 // this happens when we siglongjmp() back
1479 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1480 _crash_protection = NULL;
1481 _protected_thread = NULL;
1482 Thread::muxRelease(&_crash_mux);
1483 return false;
1484 }
1485
1486 void os::ThreadCrashProtection::restore() {
1487 assert(_crash_protection != NULL, "must have crash protection");
1488 siglongjmp(_jmpbuf, 1);
1489 }
1490
1491 void os::ThreadCrashProtection::check_crash_protection(int sig,
1492 Thread* thread) {
1493
1494 if (thread != NULL &&
1495 thread == _protected_thread &&
1496 _crash_protection != NULL) {
1497
1498 if (sig == SIGSEGV || sig == SIGBUS) {
1499 _crash_protection->restore();
1500 }
1501 }
1502 }
1503
1504 // POSIX unamed semaphores are not supported on OS X.
1505 #ifndef __APPLE__
1506
1507 PosixSemaphore::PosixSemaphore(uint value) {
1508 int ret = sem_init(&_semaphore, 0, value);
1509
1510 guarantee_with_errno(ret == 0, "Failed to initialize semaphore");
1511 }
1512
1513 PosixSemaphore::~PosixSemaphore() {
1514 sem_destroy(&_semaphore);
1515 }
1516
1517 void PosixSemaphore::signal(uint count) {
1518 for (uint i = 0; i < count; i++) {
1519 int ret = sem_post(&_semaphore);
1520
1521 assert_with_errno(ret == 0, "sem_post failed");
1522 }
1523 }
1524
1525 void PosixSemaphore::wait() {
1526 int ret;
1527
1528 do {
1529 ret = sem_wait(&_semaphore);
1530 } while (ret != 0 && errno == EINTR);
1531
1532 assert_with_errno(ret == 0, "sem_wait failed");
1533 }
1534
1535 bool PosixSemaphore::trywait() {
1536 int ret;
1537
1538 do {
1539 ret = sem_trywait(&_semaphore);
1540 } while (ret != 0 && errno == EINTR);
1541
1542 assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed");
1543
1544 return ret == 0;
1545 }
1546
1547 bool PosixSemaphore::timedwait(struct timespec ts) {
1548 while (true) {
1549 int result = sem_timedwait(&_semaphore, &ts);
1550 if (result == 0) {
1551 return true;
1552 } else if (errno == EINTR) {
1553 continue;
1554 } else if (errno == ETIMEDOUT) {
1555 return false;
1556 } else {
1557 assert_with_errno(false, "timedwait failed");
1558 return false;
1559 }
1560 }
1561 }
1562
1563 #endif // __APPLE__
1564
1565
1566 // Shared pthread_mutex/cond based PlatformEvent implementation.
1567 // Not currently usable by Solaris.
1568
1569 #ifndef SOLARIS
1570
1571 // Shared condattr object for use with relative timed-waits. Will be associated
1572 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1573 // but otherwise whatever default is used by the platform - generally the
1574 // time-of-day clock.
1575 static pthread_condattr_t _condAttr[1];
1576
1577 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1578 // all systems (e.g. FreeBSD) map the default to "normal".
1579 static pthread_mutexattr_t _mutexAttr[1];
1580
1581 // common basic initialization that is always supported
1582 static void pthread_init_common(void) {
1583 int status;
1584 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1585 fatal("pthread_condattr_init: %s", os::strerror(status));
1586 }
1587 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1588 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1589 }
1590 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1591 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1592 }
1593 }
1594
1595 // Not all POSIX types and API's are available on all notionally "posix"
1596 // platforms. If we have build-time support then we will check for actual
1597 // runtime support via dlopen/dlsym lookup. This allows for running on an
1598 // older OS version compared to the build platform. But if there is no
1599 // build time support then there cannot be any runtime support as we do not
1600 // know what the runtime types would be (for example clockid_t might be an
1601 // int or int64_t).
1602 //
1603 #ifdef SUPPORTS_CLOCK_MONOTONIC
1604
1605 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1606
1607 static int (*_clock_gettime)(clockid_t, struct timespec *);
1608 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1609
1610 static bool _use_clock_monotonic_condattr;
1611
1612 // Determine what POSIX API's are present and do appropriate
1613 // configuration.
1614 void os::Posix::init(void) {
1615
1616 // NOTE: no logging available when this is called. Put logging
1617 // statements in init_2().
1618
1619 // Copied from os::Linux::clock_init(). The duplication is temporary.
1620
1621 // 1. Check for CLOCK_MONOTONIC support.
1622
1623 void* handle = NULL;
1624
1625 // For linux we need librt, for other OS we can find
1626 // this function in regular libc.
1627 #ifdef NEEDS_LIBRT
1628 // We do dlopen's in this particular order due to bug in linux
1629 // dynamic loader (see 6348968) leading to crash on exit.
1630 handle = dlopen("librt.so.1", RTLD_LAZY);
1631 if (handle == NULL) {
1632 handle = dlopen("librt.so", RTLD_LAZY);
1633 }
1634 #endif
1635
1636 if (handle == NULL) {
1637 handle = RTLD_DEFAULT;
1638 }
1639
1640 _clock_gettime = NULL;
1641
1642 int (*clock_getres_func)(clockid_t, struct timespec*) =
1643 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1644 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1645 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1646 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1647 // We assume that if both clock_gettime and clock_getres support
1648 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1649 struct timespec res;
1650 struct timespec tp;
1651 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1652 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1653 // Yes, monotonic clock is supported.
1654 _clock_gettime = clock_gettime_func;
1655 } else {
1656 #ifdef NEEDS_LIBRT
1657 // Close librt if there is no monotonic clock.
1658 if (handle != RTLD_DEFAULT) {
1659 dlclose(handle);
1660 }
1661 #endif
1662 }
1663 }
1664
1665 // 2. Check for pthread_condattr_setclock support.
1666
1667 _pthread_condattr_setclock = NULL;
1668
1669 // libpthread is already loaded.
1670 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1671 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1672 "pthread_condattr_setclock");
1673 if (condattr_setclock_func != NULL) {
1674 _pthread_condattr_setclock = condattr_setclock_func;
1675 }
1676
1677 // Now do general initialization.
1678
1679 pthread_init_common();
1680
1681 int status;
1682 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1683 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1684 if (status == EINVAL) {
1685 _use_clock_monotonic_condattr = false;
1686 warning("Unable to use monotonic clock with relative timed-waits" \
1687 " - changes to the time-of-day clock may have adverse affects");
1688 } else {
1689 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1690 }
1691 } else {
1692 _use_clock_monotonic_condattr = true;
1693 }
1694 } else {
1695 _use_clock_monotonic_condattr = false;
1696 }
1697 }
1698
1699 void os::Posix::init_2(void) {
1700 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1701 (_clock_gettime != NULL ? "" : " not"));
1702 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1703 (_pthread_condattr_setclock != NULL ? "" : " not"));
1704 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1705 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1706 }
1707
1708 #else // !SUPPORTS_CLOCK_MONOTONIC
1709
1710 void os::Posix::init(void) {
1711 pthread_init_common();
1712 }
1713
1714 void os::Posix::init_2(void) {
1715 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1716 log_info(os)("Use of pthread_condattr_setclock is not supported");
1717 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1718 }
1719
1720 #endif // SUPPORTS_CLOCK_MONOTONIC
1721
1722 os::PlatformEvent::PlatformEvent() {
1723 int status = pthread_cond_init(_cond, _condAttr);
1724 assert_status(status == 0, status, "cond_init");
1725 status = pthread_mutex_init(_mutex, _mutexAttr);
1726 assert_status(status == 0, status, "mutex_init");
1727 _event = 0;
1728 _nParked = 0;
1729 }
1730
1731 // Utility to convert the given timeout to an absolute timespec
1732 // (based on the appropriate clock) to use with pthread_cond_timewait.
1733 // The clock queried here must be the clock used to manage the
1734 // timeout of the condition variable.
1735 //
1736 // The passed in timeout value is either a relative time in nanoseconds
1737 // or an absolute time in milliseconds. A relative timeout will be
1738 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1739 // the default time-of-day clock will be used.
1740
1741 // Given time is a 64-bit value and the time_t used in the timespec is
1742 // sometimes a signed-32-bit value we have to watch for overflow if times
1743 // way in the future are given. Further on Solaris versions
1744 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1745 // number of seconds, in abstime, is less than current_time + 100000000.
1746 // As it will be over 20 years before "now + 100000000" will overflow we can
1747 // ignore overflow and just impose a hard-limit on seconds using the value
1748 // of "now + 100000000". This places a limit on the timeout of about 3.17
1749 // years from "now".
1750 //
1751 #define MAX_SECS 100000000
1752
1753 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1754 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1755 // on which clock is being used).
1756 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1757 jlong now_part_sec, jlong unit) {
1758 time_t max_secs = now_sec + MAX_SECS;
1759
1760 jlong seconds = timeout / NANOUNITS;
1761 timeout %= NANOUNITS; // remaining nanos
1762
1763 if (seconds >= MAX_SECS) {
1764 // More seconds than we can add, so pin to max_secs.
1765 abstime->tv_sec = max_secs;
1766 abstime->tv_nsec = 0;
1767 } else {
1768 abstime->tv_sec = now_sec + seconds;
1769 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1770 if (nanos >= NANOUNITS) { // overflow
1771 abstime->tv_sec += 1;
1772 nanos -= NANOUNITS;
1773 }
1774 abstime->tv_nsec = nanos;
1775 }
1776 }
1777
1778 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1779 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1780 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1781 time_t max_secs = now_sec + MAX_SECS;
1782
1783 jlong seconds = deadline / MILLIUNITS;
1784 jlong millis = deadline % MILLIUNITS;
1785
1786 if (seconds >= max_secs) {
1787 // Absolute seconds exceeds allowed max, so pin to max_secs.
1788 abstime->tv_sec = max_secs;
1789 abstime->tv_nsec = 0;
1790 } else {
1791 abstime->tv_sec = seconds;
1792 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1793 }
1794 }
1795
1796 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1797 DEBUG_ONLY(int max_secs = MAX_SECS;)
1798
1799 if (timeout < 0) {
1800 timeout = 0;
1801 }
1802
1803 #ifdef SUPPORTS_CLOCK_MONOTONIC
1804
1805 if (_use_clock_monotonic_condattr && !isAbsolute) {
1806 struct timespec now;
1807 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1808 assert_status(status == 0, status, "clock_gettime");
1809 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1810 DEBUG_ONLY(max_secs += now.tv_sec;)
1811 } else {
1812
1813 #else
1814
1815 { // Match the block scope.
1816
1817 #endif // SUPPORTS_CLOCK_MONOTONIC
1818
1819 // Time-of-day clock is all we can reliably use.
1820 struct timeval now;
1821 int status = gettimeofday(&now, NULL);
1822 assert_status(status == 0, errno, "gettimeofday");
1823 if (isAbsolute) {
1824 unpack_abs_time(abstime, timeout, now.tv_sec);
1825 } else {
1826 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1827 }
1828 DEBUG_ONLY(max_secs += now.tv_sec;)
1829 }
1830
1831 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1832 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1833 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1834 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1835 }
1836
1837 // PlatformEvent
1838 //
1839 // Assumption:
1840 // Only one parker can exist on an event, which is why we allocate
1841 // them per-thread. Multiple unparkers can coexist.
1842 //
1843 // _event serves as a restricted-range semaphore.
1844 // -1 : thread is blocked, i.e. there is a waiter
1845 // 0 : neutral: thread is running or ready,
1846 // could have been signaled after a wait started
1847 // 1 : signaled - thread is running or ready
1848 //
1849 // Having three states allows for some detection of bad usage - see
1850 // comments on unpark().
1851
1852 void os::PlatformEvent::park() { // AKA "down()"
1853 // Transitions for _event:
1854 // -1 => -1 : illegal
1855 // 1 => 0 : pass - return immediately
1856 // 0 => -1 : block; then set _event to 0 before returning
1857
1858 // Invariant: Only the thread associated with the PlatformEvent
1859 // may call park().
1860 assert(_nParked == 0, "invariant");
1861
1862 int v;
1863
1864 // atomically decrement _event
1865 for (;;) {
1866 v = _event;
1867 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1868 }
1869 guarantee(v >= 0, "invariant");
1870
1871 if (v == 0) { // Do this the hard way by blocking ...
1872 int status = pthread_mutex_lock(_mutex);
1873 assert_status(status == 0, status, "mutex_lock");
1874 guarantee(_nParked == 0, "invariant");
1875 ++_nParked;
1876 while (_event < 0) {
1877 // OS-level "spurious wakeups" are ignored
1878 status = pthread_cond_wait(_cond, _mutex);
1879 assert_status(status == 0, status, "cond_wait");
1880 }
1881 --_nParked;
1882
1883 _event = 0;
1884 status = pthread_mutex_unlock(_mutex);
1885 assert_status(status == 0, status, "mutex_unlock");
1886 // Paranoia to ensure our locked and lock-free paths interact
1887 // correctly with each other.
1888 OrderAccess::fence();
1889 }
1890 guarantee(_event >= 0, "invariant");
1891 }
1892
1893 int os::PlatformEvent::park(jlong millis) {
1894 // Transitions for _event:
1895 // -1 => -1 : illegal
1896 // 1 => 0 : pass - return immediately
1897 // 0 => -1 : block; then set _event to 0 before returning
1898
1899 // Invariant: Only the thread associated with the Event/PlatformEvent
1900 // may call park().
1901 assert(_nParked == 0, "invariant");
1902
1903 int v;
1904 // atomically decrement _event
1905 for (;;) {
1906 v = _event;
1907 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1908 }
1909 guarantee(v >= 0, "invariant");
1910
1911 if (v == 0) { // Do this the hard way by blocking ...
1912 struct timespec abst;
1913 // We have to watch for overflow when converting millis to nanos,
1914 // but if millis is that large then we will end up limiting to
1915 // MAX_SECS anyway, so just do that here.
1916 if (millis / MILLIUNITS > MAX_SECS) {
1917 millis = jlong(MAX_SECS) * MILLIUNITS;
1918 }
1919 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1920
1921 int ret = OS_TIMEOUT;
1922 int status = pthread_mutex_lock(_mutex);
1923 assert_status(status == 0, status, "mutex_lock");
1924 guarantee(_nParked == 0, "invariant");
1925 ++_nParked;
1926
1927 while (_event < 0) {
1928 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1929 assert_status(status == 0 || status == ETIMEDOUT,
1930 status, "cond_timedwait");
1931 // OS-level "spurious wakeups" are ignored unless the archaic
1932 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1933 if (!FilterSpuriousWakeups) break;
1934 if (status == ETIMEDOUT) break;
1935 }
1936 --_nParked;
1937
1938 if (_event >= 0) {
1939 ret = OS_OK;
1940 }
1941
1942 _event = 0;
1943 status = pthread_mutex_unlock(_mutex);
1944 assert_status(status == 0, status, "mutex_unlock");
1945 // Paranoia to ensure our locked and lock-free paths interact
1946 // correctly with each other.
1947 OrderAccess::fence();
1948 return ret;
1949 }
1950 return OS_OK;
1951 }
1952
1953 void os::PlatformEvent::unpark() {
1954 // Transitions for _event:
1955 // 0 => 1 : just return
1956 // 1 => 1 : just return
1957 // -1 => either 0 or 1; must signal target thread
1958 // That is, we can safely transition _event from -1 to either
1959 // 0 or 1.
1960 // See also: "Semaphores in Plan 9" by Mullender & Cox
1961 //
1962 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1963 // that it will take two back-to-back park() calls for the owning
1964 // thread to block. This has the benefit of forcing a spurious return
1965 // from the first park() call after an unpark() call which will help
1966 // shake out uses of park() and unpark() without checking state conditions
1967 // properly. This spurious return doesn't manifest itself in any user code
1968 // but only in the correctly written condition checking loops of ObjectMonitor,
1969 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1970
1971 if (Atomic::xchg(1, &_event) >= 0) return;
1972
1973 int status = pthread_mutex_lock(_mutex);
1974 assert_status(status == 0, status, "mutex_lock");
1975 int anyWaiters = _nParked;
1976 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1977 status = pthread_mutex_unlock(_mutex);
1978 assert_status(status == 0, status, "mutex_unlock");
1979
1980 // Note that we signal() *after* dropping the lock for "immortal" Events.
1981 // This is safe and avoids a common class of futile wakeups. In rare
1982 // circumstances this can cause a thread to return prematurely from
1983 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1984 // will simply re-test the condition and re-park itself.
1985 // This provides particular benefit if the underlying platform does not
1986 // provide wait morphing.
1987
1988 if (anyWaiters != 0) {
1989 status = pthread_cond_signal(_cond);
1990 assert_status(status == 0, status, "cond_signal");
1991 }
1992 }
1993
1994 // JSR166 support
1995
1996 os::PlatformParker::PlatformParker() {
1997 int status;
1998 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1999 assert_status(status == 0, status, "cond_init rel");
2000 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
2001 assert_status(status == 0, status, "cond_init abs");
2002 status = pthread_mutex_init(_mutex, _mutexAttr);
2003 assert_status(status == 0, status, "mutex_init");
2004 _cur_index = -1; // mark as unused
2005 }
2006
2007 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
2008 // sets count to 1 and signals condvar. Only one thread ever waits
2009 // on the condvar. Contention seen when trying to park implies that someone
2010 // is unparking you, so don't wait. And spurious returns are fine, so there
2011 // is no need to track notifications.
2012
2013 void Parker::park(bool isAbsolute, jlong time) {
2014
2015 // Optional fast-path check:
2016 // Return immediately if a permit is available.
2017 // We depend on Atomic::xchg() having full barrier semantics
2018 // since we are doing a lock-free update to _counter.
2019 if (Atomic::xchg(0, &_counter) > 0) return;
2020
2021 Thread* thread = Thread::current();
2022 assert(thread->is_Java_thread(), "Must be JavaThread");
2023 JavaThread *jt = (JavaThread *)thread;
2024
2025 // Optional optimization -- avoid state transitions if there's
2026 // an interrupt pending.
2027 if (Thread::is_interrupted(thread, false)) {
2028 return;
2029 }
2030
2031 // Next, demultiplex/decode time arguments
2032 struct timespec absTime;
2033 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
2034 return;
2035 }
2036 if (time > 0) {
2037 to_abstime(&absTime, time, isAbsolute);
2038 }
2039
2040 // Enter safepoint region
2041 // Beware of deadlocks such as 6317397.
2042 // The per-thread Parker:: mutex is a classic leaf-lock.
2043 // In particular a thread must never block on the Threads_lock while
2044 // holding the Parker:: mutex. If safepoints are pending both the
2045 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
2046 ThreadBlockInVM tbivm(jt);
2047
2048 // Don't wait if cannot get lock since interference arises from
2049 // unparking. Also re-check interrupt before trying wait.
2050 if (Thread::is_interrupted(thread, false) ||
2051 pthread_mutex_trylock(_mutex) != 0) {
2052 return;
2053 }
2054
2055 int status;
2056 if (_counter > 0) { // no wait needed
2057 _counter = 0;
2058 status = pthread_mutex_unlock(_mutex);
2059 assert_status(status == 0, status, "invariant");
2060 // Paranoia to ensure our locked and lock-free paths interact
2061 // correctly with each other and Java-level accesses.
2062 OrderAccess::fence();
2063 return;
2064 }
2065
2066 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2067 jt->set_suspend_equivalent();
2068 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2069
2070 assert(_cur_index == -1, "invariant");
2071 if (time == 0) {
2072 _cur_index = REL_INDEX; // arbitrary choice when not timed
2073 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
2074 assert_status(status == 0, status, "cond_timedwait");
2075 }
2076 else {
2077 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
2078 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
2079 assert_status(status == 0 || status == ETIMEDOUT,
2080 status, "cond_timedwait");
2081 }
2082 _cur_index = -1;
2083
2084 _counter = 0;
2085 status = pthread_mutex_unlock(_mutex);
2086 assert_status(status == 0, status, "invariant");
2087 // Paranoia to ensure our locked and lock-free paths interact
2088 // correctly with each other and Java-level accesses.
2089 OrderAccess::fence();
2090
2091 // If externally suspended while waiting, re-suspend
2092 if (jt->handle_special_suspend_equivalent_condition()) {
2093 jt->java_suspend_self();
2094 }
2095 }
2096
2097 void Parker::unpark() {
2098 int status = pthread_mutex_lock(_mutex);
2099 assert_status(status == 0, status, "invariant");
2100 const int s = _counter;
2101 _counter = 1;
2102 // must capture correct index before unlocking
2103 int index = _cur_index;
2104 status = pthread_mutex_unlock(_mutex);
2105 assert_status(status == 0, status, "invariant");
2106
2107 // Note that we signal() *after* dropping the lock for "immortal" Events.
2108 // This is safe and avoids a common class of futile wakeups. In rare
2109 // circumstances this can cause a thread to return prematurely from
2110 // cond_{timed}wait() but the spurious wakeup is benign and the victim
2111 // will simply re-test the condition and re-park itself.
2112 // This provides particular benefit if the underlying platform does not
2113 // provide wait morphing.
2114
2115 if (s < 1 && index != -1) {
2116 // thread is definitely parked
2117 status = pthread_cond_signal(&_cond[index]);
2118 assert_status(status == 0, status, "invariant");
2119 }
2120 }
2121
2122
2123 #endif // !SOLARIS