1 /*
2 * Copyright (c) 1999, 2018, 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 "logging/log.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "utilities/globalDefinitions.hpp"
29 #include "runtime/frame.inline.hpp"
30 #include "runtime/interfaceSupport.inline.hpp"
31 #include "runtime/os.hpp"
32 #include "services/memTracker.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/formatBuffer.hpp"
35 #include "utilities/macros.hpp"
36 #include "utilities/vmError.hpp"
37
38 #include <dlfcn.h>
39 #include <pthread.h>
40 #include <signal.h>
41 #include <sys/mman.h>
42 #include <sys/resource.h>
43 #include <sys/utsname.h>
44 #include <time.h>
45 #include <unistd.h>
46
47 // Todo: provide a os::get_max_process_id() or similar. Number of processes
48 // may have been configured, can be read more accurately from proc fs etc.
49 #ifndef MAX_PID
50 #define MAX_PID INT_MAX
51 #endif
52 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
53
54 #define ROOT_UID 0
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 NOT_AIX( | 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 int ret = util_posix_fallocate(fd, 0, (off_t)size);
247 if (ret != 0) {
248 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory. error(%d)", ret));
249 return NULL;
250 }
251
252 int prot = PROT_READ | PROT_WRITE;
253 int flags = MAP_SHARED;
254 if (base != NULL) {
255 flags |= MAP_FIXED;
256 }
257 char* addr = (char*)mmap(base, size, prot, flags, fd, 0);
258
259 if (addr == MAP_FAILED) {
260 warning("Failed mmap to file. (%s)", os::strerror(errno));
261 return NULL;
262 }
263 if (base != NULL && addr != base) {
264 if (!os::release_memory(addr, size)) {
265 warning("Could not release memory on unsuccessful file mapping");
266 }
267 return NULL;
268 }
269 return addr;
270 }
271
272 char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) {
273 assert(fd != -1, "File descriptor is not valid");
274 assert(base != NULL, "Base cannot be NULL");
275
276 return map_memory_to_file(base, size, fd);
277 }
278
279 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
280 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
281 // rather than unmapping and remapping the whole chunk to get requested alignment.
282 char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) {
283 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
284 "Alignment must be a multiple of allocation granularity (page size)");
285 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
286
287 size_t extra_size = size + alignment;
288 assert(extra_size >= size, "overflow, size is too large to allow alignment");
289
290 char* extra_base;
291 if (file_desc != -1) {
292 // For file mapping, we do not call os:reserve_memory(extra_size, NULL, alignment, file_desc) because
293 // we need to deal with shrinking of the file space later when we release extra memory after alignment.
294 // We also cannot called os:reserve_memory() with file_desc set to -1 because on aix we might get SHM memory.
295 // So here to call a helper function while reserve memory for us. After we have a aligned base,
296 // we will replace anonymous mapping with file mapping.
297 extra_base = reserve_mmapped_memory(extra_size, NULL);
298 if (extra_base != NULL) {
299 MemTracker::record_virtual_memory_reserve((address)extra_base, extra_size, CALLER_PC);
300 }
301 } else {
302 extra_base = os::reserve_memory(extra_size, NULL, alignment);
303 }
304
305 if (extra_base == NULL) {
306 return NULL;
307 }
308
309 // Do manual alignment
310 char* aligned_base = align_up(extra_base, alignment);
311
312 // [ | | ]
313 // ^ extra_base
314 // ^ extra_base + begin_offset == aligned_base
315 // extra_base + begin_offset + size ^
316 // extra_base + extra_size ^
317 // |<>| == begin_offset
318 // end_offset == |<>|
319 size_t begin_offset = aligned_base - extra_base;
320 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
321
322 if (begin_offset > 0) {
323 os::release_memory(extra_base, begin_offset);
324 }
325
326 if (end_offset > 0) {
327 os::release_memory(extra_base + begin_offset + size, end_offset);
328 }
329
330 if (file_desc != -1) {
331 // After we have an aligned address, we can replace anonymous mapping with file mapping
332 if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) {
333 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
334 }
335 MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC);
336 }
337 return aligned_base;
338 }
339
340 int os::vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
341 // All supported POSIX platforms provide C99 semantics.
342 int result = ::vsnprintf(buf, len, fmt, args);
343 // If an encoding error occurred (result < 0) then it's not clear
344 // whether the buffer is NUL terminated, so ensure it is.
345 if ((result < 0) && (len > 0)) {
346 buf[len - 1] = '\0';
347 }
348 return result;
349 }
350
351 int os::get_fileno(FILE* fp) {
352 return NOT_AIX(::)fileno(fp);
353 }
354
355 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
356 return gmtime_r(clock, res);
357 }
358
359 void os::Posix::print_load_average(outputStream* st) {
360 st->print("load average:");
361 double loadavg[3];
362 os::loadavg(loadavg, 3);
363 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
364 st->cr();
365 }
366
367 void os::Posix::print_rlimit_info(outputStream* st) {
368 st->print("rlimit:");
369 struct rlimit rlim;
370
371 st->print(" STACK ");
372 getrlimit(RLIMIT_STACK, &rlim);
373 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
374 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
375
376 st->print(", CORE ");
377 getrlimit(RLIMIT_CORE, &rlim);
378 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
379 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
380
381 // Isn't there on solaris
382 #if defined(AIX)
383 st->print(", NPROC ");
384 st->print("%d", sysconf(_SC_CHILD_MAX));
385 #elif !defined(SOLARIS)
386 st->print(", NPROC ");
387 getrlimit(RLIMIT_NPROC, &rlim);
388 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
389 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
390 #endif
391
392 st->print(", NOFILE ");
393 getrlimit(RLIMIT_NOFILE, &rlim);
394 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
395 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
396
397 st->print(", AS ");
398 getrlimit(RLIMIT_AS, &rlim);
399 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
400 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
401
402 st->print(", DATA ");
403 getrlimit(RLIMIT_DATA, &rlim);
404 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
405 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
406
407 st->print(", FSIZE ");
408 getrlimit(RLIMIT_FSIZE, &rlim);
409 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
410 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
411
412 st->cr();
413 }
414
415 void os::Posix::print_uname_info(outputStream* st) {
416 // kernel
417 st->print("uname:");
418 struct utsname name;
419 uname(&name);
420 st->print("%s ", name.sysname);
421 #ifdef ASSERT
422 st->print("%s ", name.nodename);
423 #endif
424 st->print("%s ", name.release);
425 st->print("%s ", name.version);
426 st->print("%s", name.machine);
427 st->cr();
428 }
429
430 bool os::get_host_name(char* buf, size_t buflen) {
431 struct utsname name;
432 uname(&name);
433 jio_snprintf(buf, buflen, "%s", name.nodename);
434 return true;
435 }
436
437 bool os::has_allocatable_memory_limit(julong* limit) {
438 struct rlimit rlim;
439 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
440 // if there was an error when calling getrlimit, assume that there is no limitation
441 // on virtual memory.
442 bool result;
443 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
444 result = false;
445 } else {
446 *limit = (julong)rlim.rlim_cur;
447 result = true;
448 }
449 #ifdef _LP64
450 return result;
451 #else
452 // arbitrary virtual space limit for 32 bit Unices found by testing. If
453 // getrlimit above returned a limit, bound it with this limit. Otherwise
454 // directly use it.
455 const julong max_virtual_limit = (julong)3800*M;
456 if (result) {
457 *limit = MIN2(*limit, max_virtual_limit);
458 } else {
459 *limit = max_virtual_limit;
460 }
461
462 // bound by actually allocatable memory. The algorithm uses two bounds, an
463 // upper and a lower limit. The upper limit is the current highest amount of
464 // memory that could not be allocated, the lower limit is the current highest
465 // amount of memory that could be allocated.
466 // The algorithm iteratively refines the result by halving the difference
467 // between these limits, updating either the upper limit (if that value could
468 // not be allocated) or the lower limit (if the that value could be allocated)
469 // until the difference between these limits is "small".
470
471 // the minimum amount of memory we care about allocating.
472 const julong min_allocation_size = M;
473
474 julong upper_limit = *limit;
475
476 // first check a few trivial cases
477 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
478 *limit = upper_limit;
479 } else if (!is_allocatable(min_allocation_size)) {
480 // we found that not even min_allocation_size is allocatable. Return it
481 // anyway. There is no point to search for a better value any more.
482 *limit = min_allocation_size;
483 } else {
484 // perform the binary search.
485 julong lower_limit = min_allocation_size;
486 while ((upper_limit - lower_limit) > min_allocation_size) {
487 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
488 temp_limit = align_down(temp_limit, min_allocation_size);
489 if (is_allocatable(temp_limit)) {
490 lower_limit = temp_limit;
491 } else {
492 upper_limit = temp_limit;
493 }
494 }
495 *limit = lower_limit;
496 }
497 return true;
498 #endif
499 }
500
501 const char* os::get_current_directory(char *buf, size_t buflen) {
502 return getcwd(buf, buflen);
503 }
504
505 FILE* os::open(int fd, const char* mode) {
506 return ::fdopen(fd, mode);
507 }
508
509 void os::flockfile(FILE* fp) {
510 ::flockfile(fp);
511 }
512
513 void os::funlockfile(FILE* fp) {
514 ::funlockfile(fp);
515 }
516
517 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
518 // which is used to find statically linked in agents.
519 // Parameters:
520 // sym_name: Symbol in library we are looking for
521 // lib_name: Name of library to look in, NULL for shared libs.
522 // is_absolute_path == true if lib_name is absolute path to agent
523 // such as "/a/b/libL.so"
524 // == false if only the base name of the library is passed in
525 // such as "L"
526 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
527 bool is_absolute_path) {
528 char *agent_entry_name;
529 size_t len;
530 size_t name_len;
531 size_t prefix_len = strlen(JNI_LIB_PREFIX);
532 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
533 const char *start;
534
535 if (lib_name != NULL) {
536 name_len = strlen(lib_name);
537 if (is_absolute_path) {
538 // Need to strip path, prefix and suffix
539 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
540 lib_name = ++start;
541 }
542 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
543 return NULL;
544 }
545 lib_name += prefix_len;
546 name_len = strlen(lib_name) - suffix_len;
547 }
548 }
549 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
550 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
551 if (agent_entry_name == NULL) {
552 return NULL;
553 }
554 strcpy(agent_entry_name, sym_name);
555 if (lib_name != NULL) {
556 strcat(agent_entry_name, "_");
557 strncat(agent_entry_name, lib_name, name_len);
558 }
559 return agent_entry_name;
560 }
561
562 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
563 assert(thread == Thread::current(), "thread consistency check");
564
565 ParkEvent * const slp = thread->_SleepEvent ;
566 slp->reset() ;
567 OrderAccess::fence() ;
568
569 if (interruptible) {
570 jlong prevtime = javaTimeNanos();
571
572 for (;;) {
573 if (os::is_interrupted(thread, true)) {
574 return OS_INTRPT;
575 }
576
577 jlong newtime = javaTimeNanos();
578
579 if (newtime - prevtime < 0) {
580 // time moving backwards, should only happen if no monotonic clock
581 // not a guarantee() because JVM should not abort on kernel/glibc bugs
582 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
583 } else {
584 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
585 }
586
587 if (millis <= 0) {
588 return OS_OK;
589 }
590
591 prevtime = newtime;
592
593 {
594 assert(thread->is_Java_thread(), "sanity check");
595 JavaThread *jt = (JavaThread *) thread;
596 ThreadBlockInVM tbivm(jt);
597 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
598
599 jt->set_suspend_equivalent();
600 // cleared by handle_special_suspend_equivalent_condition() or
601 // java_suspend_self() via check_and_wait_while_suspended()
602
603 slp->park(millis);
604
605 // were we externally suspended while we were waiting?
606 jt->check_and_wait_while_suspended();
607 }
608 }
609 } else {
610 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
611 jlong prevtime = javaTimeNanos();
612
613 for (;;) {
614 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
615 // the 1st iteration ...
616 jlong newtime = javaTimeNanos();
617
618 if (newtime - prevtime < 0) {
619 // time moving backwards, should only happen if no monotonic clock
620 // not a guarantee() because JVM should not abort on kernel/glibc bugs
621 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
622 } else {
623 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
624 }
625
626 if (millis <= 0) break ;
627
628 prevtime = newtime;
629 slp->park(millis);
630 }
631 return OS_OK ;
632 }
633 }
634
635 ////////////////////////////////////////////////////////////////////////////////
636 // interrupt support
637
638 void os::interrupt(Thread* thread) {
639 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
640
641 OSThread* osthread = thread->osthread();
642
643 if (!osthread->interrupted()) {
644 osthread->set_interrupted(true);
645 // More than one thread can get here with the same value of osthread,
646 // resulting in multiple notifications. We do, however, want the store
647 // to interrupted() to be visible to other threads before we execute unpark().
648 OrderAccess::fence();
649 ParkEvent * const slp = thread->_SleepEvent ;
650 if (slp != NULL) slp->unpark() ;
651 }
652
653 // For JSR166. Unpark even if interrupt status already was set
654 if (thread->is_Java_thread())
655 ((JavaThread*)thread)->parker()->unpark();
656
657 ParkEvent * ev = thread->_ParkEvent ;
658 if (ev != NULL) ev->unpark() ;
659 }
660
661 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
662 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
663
664 OSThread* osthread = thread->osthread();
665
666 bool interrupted = osthread->interrupted();
667
668 // NOTE that since there is no "lock" around the interrupt and
669 // is_interrupted operations, there is the possibility that the
670 // interrupted flag (in osThread) will be "false" but that the
671 // low-level events will be in the signaled state. This is
672 // intentional. The effect of this is that Object.wait() and
673 // LockSupport.park() will appear to have a spurious wakeup, which
674 // is allowed and not harmful, and the possibility is so rare that
675 // it is not worth the added complexity to add yet another lock.
676 // For the sleep event an explicit reset is performed on entry
677 // to os::sleep, so there is no early return. It has also been
678 // recommended not to put the interrupted flag into the "event"
679 // structure because it hides the issue.
680 if (interrupted && clear_interrupted) {
681 osthread->set_interrupted(false);
682 // consider thread->_SleepEvent->reset() ... optional optimization
683 }
684
685 return interrupted;
686 }
687
688
689
690 static const struct {
691 int sig; const char* name;
692 }
693 g_signal_info[] =
694 {
695 { SIGABRT, "SIGABRT" },
696 #ifdef SIGAIO
697 { SIGAIO, "SIGAIO" },
698 #endif
699 { SIGALRM, "SIGALRM" },
700 #ifdef SIGALRM1
701 { SIGALRM1, "SIGALRM1" },
702 #endif
703 { SIGBUS, "SIGBUS" },
704 #ifdef SIGCANCEL
705 { SIGCANCEL, "SIGCANCEL" },
706 #endif
707 { SIGCHLD, "SIGCHLD" },
708 #ifdef SIGCLD
709 { SIGCLD, "SIGCLD" },
710 #endif
711 { SIGCONT, "SIGCONT" },
712 #ifdef SIGCPUFAIL
713 { SIGCPUFAIL, "SIGCPUFAIL" },
714 #endif
715 #ifdef SIGDANGER
716 { SIGDANGER, "SIGDANGER" },
717 #endif
718 #ifdef SIGDIL
719 { SIGDIL, "SIGDIL" },
720 #endif
721 #ifdef SIGEMT
722 { SIGEMT, "SIGEMT" },
723 #endif
724 { SIGFPE, "SIGFPE" },
725 #ifdef SIGFREEZE
726 { SIGFREEZE, "SIGFREEZE" },
727 #endif
728 #ifdef SIGGFAULT
729 { SIGGFAULT, "SIGGFAULT" },
730 #endif
731 #ifdef SIGGRANT
732 { SIGGRANT, "SIGGRANT" },
733 #endif
734 { SIGHUP, "SIGHUP" },
735 { SIGILL, "SIGILL" },
736 { SIGINT, "SIGINT" },
737 #ifdef SIGIO
738 { SIGIO, "SIGIO" },
739 #endif
740 #ifdef SIGIOINT
741 { SIGIOINT, "SIGIOINT" },
742 #endif
743 #ifdef SIGIOT
744 // SIGIOT is there for BSD compatibility, but on most Unices just a
745 // synonym for SIGABRT. The result should be "SIGABRT", not
746 // "SIGIOT".
747 #if (SIGIOT != SIGABRT )
748 { SIGIOT, "SIGIOT" },
749 #endif
750 #endif
751 #ifdef SIGKAP
752 { SIGKAP, "SIGKAP" },
753 #endif
754 { SIGKILL, "SIGKILL" },
755 #ifdef SIGLOST
756 { SIGLOST, "SIGLOST" },
757 #endif
758 #ifdef SIGLWP
759 { SIGLWP, "SIGLWP" },
760 #endif
761 #ifdef SIGLWPTIMER
762 { SIGLWPTIMER, "SIGLWPTIMER" },
763 #endif
764 #ifdef SIGMIGRATE
765 { SIGMIGRATE, "SIGMIGRATE" },
766 #endif
767 #ifdef SIGMSG
768 { SIGMSG, "SIGMSG" },
769 #endif
770 { SIGPIPE, "SIGPIPE" },
771 #ifdef SIGPOLL
772 { SIGPOLL, "SIGPOLL" },
773 #endif
774 #ifdef SIGPRE
775 { SIGPRE, "SIGPRE" },
776 #endif
777 { SIGPROF, "SIGPROF" },
778 #ifdef SIGPTY
779 { SIGPTY, "SIGPTY" },
780 #endif
781 #ifdef SIGPWR
782 { SIGPWR, "SIGPWR" },
783 #endif
784 { SIGQUIT, "SIGQUIT" },
785 #ifdef SIGRECONFIG
786 { SIGRECONFIG, "SIGRECONFIG" },
787 #endif
788 #ifdef SIGRECOVERY
789 { SIGRECOVERY, "SIGRECOVERY" },
790 #endif
791 #ifdef SIGRESERVE
792 { SIGRESERVE, "SIGRESERVE" },
793 #endif
794 #ifdef SIGRETRACT
795 { SIGRETRACT, "SIGRETRACT" },
796 #endif
797 #ifdef SIGSAK
798 { SIGSAK, "SIGSAK" },
799 #endif
800 { SIGSEGV, "SIGSEGV" },
801 #ifdef SIGSOUND
802 { SIGSOUND, "SIGSOUND" },
803 #endif
804 #ifdef SIGSTKFLT
805 { SIGSTKFLT, "SIGSTKFLT" },
806 #endif
807 { SIGSTOP, "SIGSTOP" },
808 { SIGSYS, "SIGSYS" },
809 #ifdef SIGSYSERROR
810 { SIGSYSERROR, "SIGSYSERROR" },
811 #endif
812 #ifdef SIGTALRM
813 { SIGTALRM, "SIGTALRM" },
814 #endif
815 { SIGTERM, "SIGTERM" },
816 #ifdef SIGTHAW
817 { SIGTHAW, "SIGTHAW" },
818 #endif
819 { SIGTRAP, "SIGTRAP" },
820 #ifdef SIGTSTP
821 { SIGTSTP, "SIGTSTP" },
822 #endif
823 { SIGTTIN, "SIGTTIN" },
824 { SIGTTOU, "SIGTTOU" },
825 #ifdef SIGURG
826 { SIGURG, "SIGURG" },
827 #endif
828 { SIGUSR1, "SIGUSR1" },
829 { SIGUSR2, "SIGUSR2" },
830 #ifdef SIGVIRT
831 { SIGVIRT, "SIGVIRT" },
832 #endif
833 { SIGVTALRM, "SIGVTALRM" },
834 #ifdef SIGWAITING
835 { SIGWAITING, "SIGWAITING" },
836 #endif
837 #ifdef SIGWINCH
838 { SIGWINCH, "SIGWINCH" },
839 #endif
840 #ifdef SIGWINDOW
841 { SIGWINDOW, "SIGWINDOW" },
842 #endif
843 { SIGXCPU, "SIGXCPU" },
844 { SIGXFSZ, "SIGXFSZ" },
845 #ifdef SIGXRES
846 { SIGXRES, "SIGXRES" },
847 #endif
848 { -1, NULL }
849 };
850
851 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
852 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
853
854 const char* ret = NULL;
855
856 #ifdef SIGRTMIN
857 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
858 if (sig == SIGRTMIN) {
859 ret = "SIGRTMIN";
860 } else if (sig == SIGRTMAX) {
861 ret = "SIGRTMAX";
862 } else {
863 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
864 return out;
865 }
866 }
867 #endif
868
869 if (sig > 0) {
870 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
871 if (g_signal_info[idx].sig == sig) {
872 ret = g_signal_info[idx].name;
873 break;
874 }
875 }
876 }
877
878 if (!ret) {
879 if (!is_valid_signal(sig)) {
880 ret = "INVALID";
881 } else {
882 ret = "UNKNOWN";
883 }
884 }
885
886 if (out && outlen > 0) {
887 strncpy(out, ret, outlen);
888 out[outlen - 1] = '\0';
889 }
890 return out;
891 }
892
893 int os::Posix::get_signal_number(const char* signal_name) {
894 char tmp[30];
895 const char* s = signal_name;
896 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
897 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
898 s = tmp;
899 }
900 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
901 if (strcmp(g_signal_info[idx].name, s) == 0) {
902 return g_signal_info[idx].sig;
903 }
904 }
905 return -1;
906 }
907
908 int os::get_signal_number(const char* signal_name) {
909 return os::Posix::get_signal_number(signal_name);
910 }
911
912 // Returns true if signal number is valid.
913 bool os::Posix::is_valid_signal(int sig) {
914 // MacOS not really POSIX compliant: sigaddset does not return
915 // an error for invalid signal numbers. However, MacOS does not
916 // support real time signals and simply seems to have just 33
917 // signals with no holes in the signal range.
918 #ifdef __APPLE__
919 return sig >= 1 && sig < NSIG;
920 #else
921 // Use sigaddset to check for signal validity.
922 sigset_t set;
923 sigemptyset(&set);
924 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
925 return false;
926 }
927 return true;
928 #endif
929 }
930
931 bool os::Posix::is_sig_ignored(int sig) {
932 struct sigaction oact;
933 sigaction(sig, (struct sigaction*)NULL, &oact);
934 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
935 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
936 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
937 return true;
938 } else {
939 return false;
940 }
941 }
942
943 // Returns:
944 // NULL for an invalid signal number
945 // "SIG<num>" for a valid but unknown signal number
946 // signal name otherwise.
947 const char* os::exception_name(int sig, char* buf, size_t size) {
948 if (!os::Posix::is_valid_signal(sig)) {
949 return NULL;
950 }
951 const char* const name = os::Posix::get_signal_name(sig, buf, size);
952 if (strcmp(name, "UNKNOWN") == 0) {
953 jio_snprintf(buf, size, "SIG%d", sig);
954 }
955 return buf;
956 }
957
958 #define NUM_IMPORTANT_SIGS 32
959 // Returns one-line short description of a signal set in a user provided buffer.
960 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
961 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
962 // Note: for shortness, just print out the first 32. That should
963 // cover most of the useful ones, apart from realtime signals.
964 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
965 const int rc = sigismember(set, sig);
966 if (rc == -1 && errno == EINVAL) {
967 buffer[sig-1] = '?';
968 } else {
969 buffer[sig-1] = rc == 0 ? '0' : '1';
970 }
971 }
972 buffer[NUM_IMPORTANT_SIGS] = 0;
973 return buffer;
974 }
975
976 // Prints one-line description of a signal set.
977 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
978 char buf[NUM_IMPORTANT_SIGS + 1];
979 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
980 st->print("%s", buf);
981 }
982
983 // Writes one-line description of a combination of sigaction.sa_flags into a user
984 // provided buffer. Returns that buffer.
985 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
986 char* p = buffer;
987 size_t remaining = size;
988 bool first = true;
989 int idx = 0;
990
991 assert(buffer, "invalid argument");
992
993 if (size == 0) {
994 return buffer;
995 }
996
997 strncpy(buffer, "none", size);
998
999 const struct {
1000 // NB: i is an unsigned int here because SA_RESETHAND is on some
1001 // systems 0x80000000, which is implicitly unsigned. Assignining
1002 // it to an int field would be an overflow in unsigned-to-signed
1003 // conversion.
1004 unsigned int i;
1005 const char* s;
1006 } flaginfo [] = {
1007 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
1008 { SA_ONSTACK, "SA_ONSTACK" },
1009 { SA_RESETHAND, "SA_RESETHAND" },
1010 { SA_RESTART, "SA_RESTART" },
1011 { SA_SIGINFO, "SA_SIGINFO" },
1012 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
1013 { SA_NODEFER, "SA_NODEFER" },
1014 #ifdef AIX
1015 { SA_ONSTACK, "SA_ONSTACK" },
1016 { SA_OLDSTYLE, "SA_OLDSTYLE" },
1017 #endif
1018 { 0, NULL }
1019 };
1020
1021 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
1022 if (flags & flaginfo[idx].i) {
1023 if (first) {
1024 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
1025 first = false;
1026 } else {
1027 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
1028 }
1029 const size_t len = strlen(p);
1030 p += len;
1031 remaining -= len;
1032 }
1033 }
1034
1035 buffer[size - 1] = '\0';
1036
1037 return buffer;
1038 }
1039
1040 // Prints one-line description of a combination of sigaction.sa_flags.
1041 void os::Posix::print_sa_flags(outputStream* st, int flags) {
1042 char buffer[0x100];
1043 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
1044 st->print("%s", buffer);
1045 }
1046
1047 // Helper function for os::Posix::print_siginfo_...():
1048 // return a textual description for signal code.
1049 struct enum_sigcode_desc_t {
1050 const char* s_name;
1051 const char* s_desc;
1052 };
1053
1054 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
1055
1056 const struct {
1057 int sig; int code; const char* s_code; const char* s_desc;
1058 } t1 [] = {
1059 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
1060 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
1061 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
1062 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
1063 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
1064 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
1065 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
1066 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
1067 #if defined(IA64) && defined(LINUX)
1068 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
1069 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
1070 #endif
1071 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
1072 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
1073 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
1074 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
1075 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
1076 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
1077 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
1078 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
1079 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
1080 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
1081 #ifdef AIX
1082 // no explanation found what keyerr would be
1083 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
1084 #endif
1085 #if defined(IA64) && !defined(AIX)
1086 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
1087 #endif
1088 #if defined(__sparc) && defined(SOLARIS)
1089 // define Solaris Sparc M7 ADI SEGV signals
1090 #if !defined(SEGV_ACCADI)
1091 #define SEGV_ACCADI 3
1092 #endif
1093 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
1094 #if !defined(SEGV_ACCDERR)
1095 #define SEGV_ACCDERR 4
1096 #endif
1097 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
1098 #if !defined(SEGV_ACCPERR)
1099 #define SEGV_ACCPERR 5
1100 #endif
1101 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
1102 #endif // defined(__sparc) && defined(SOLARIS)
1103 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
1104 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
1105 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
1106 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
1107 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
1108 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
1109 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
1110 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
1111 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
1112 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
1113 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
1114 #ifdef SIGPOLL
1115 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
1116 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
1117 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
1118 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
1119 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
1120 #endif
1121 { -1, -1, NULL, NULL }
1122 };
1123
1124 // Codes valid in any signal context.
1125 const struct {
1126 int code; const char* s_code; const char* s_desc;
1127 } t2 [] = {
1128 { SI_USER, "SI_USER", "Signal sent by kill()." },
1129 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
1130 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
1131 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
1132 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
1133 // Linux specific
1134 #ifdef SI_TKILL
1135 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
1136 #endif
1137 #ifdef SI_DETHREAD
1138 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
1139 #endif
1140 #ifdef SI_KERNEL
1141 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
1142 #endif
1143 #ifdef SI_SIGIO
1144 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
1145 #endif
1146
1147 #ifdef AIX
1148 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
1149 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
1150 #endif
1151
1152 #ifdef __sun
1153 { SI_NOINFO, "SI_NOINFO", "No signal information" },
1154 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
1155 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
1156 #endif
1157
1158 { -1, NULL, NULL }
1159 };
1160
1161 const char* s_code = NULL;
1162 const char* s_desc = NULL;
1163
1164 for (int i = 0; t1[i].sig != -1; i ++) {
1165 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
1166 s_code = t1[i].s_code;
1167 s_desc = t1[i].s_desc;
1168 break;
1169 }
1170 }
1171
1172 if (s_code == NULL) {
1173 for (int i = 0; t2[i].s_code != NULL; i ++) {
1174 if (t2[i].code == si->si_code) {
1175 s_code = t2[i].s_code;
1176 s_desc = t2[i].s_desc;
1177 }
1178 }
1179 }
1180
1181 if (s_code == NULL) {
1182 out->s_name = "unknown";
1183 out->s_desc = "unknown";
1184 return false;
1185 }
1186
1187 out->s_name = s_code;
1188 out->s_desc = s_desc;
1189
1190 return true;
1191 }
1192
1193 void os::print_siginfo(outputStream* os, const void* si0) {
1194
1195 const siginfo_t* const si = (const siginfo_t*) si0;
1196
1197 char buf[20];
1198 os->print("siginfo:");
1199
1200 if (!si) {
1201 os->print(" <null>");
1202 return;
1203 }
1204
1205 const int sig = si->si_signo;
1206
1207 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1208
1209 enum_sigcode_desc_t ed;
1210 get_signal_code_description(si, &ed);
1211 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1212
1213 if (si->si_errno) {
1214 os->print(", si_errno: %d", si->si_errno);
1215 }
1216
1217 // Output additional information depending on the signal code.
1218
1219 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1220 // so it depends on the context which member to use. For synchronous error signals,
1221 // we print si_addr, unless the signal was sent by another process or thread, in
1222 // which case we print out pid or tid of the sender.
1223 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1224 const pid_t pid = si->si_pid;
1225 os->print(", si_pid: %ld", (long) pid);
1226 if (IS_VALID_PID(pid)) {
1227 const pid_t me = getpid();
1228 if (me == pid) {
1229 os->print(" (current process)");
1230 }
1231 } else {
1232 os->print(" (invalid)");
1233 }
1234 os->print(", si_uid: %ld", (long) si->si_uid);
1235 if (sig == SIGCHLD) {
1236 os->print(", si_status: %d", si->si_status);
1237 }
1238 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1239 sig == SIGTRAP || sig == SIGFPE) {
1240 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1241 #ifdef SIGPOLL
1242 } else if (sig == SIGPOLL) {
1243 os->print(", si_band: %ld", si->si_band);
1244 #endif
1245 }
1246
1247 }
1248
1249 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1250 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1251 }
1252
1253 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1254 #if defined(AIX)
1255 return Aix::ucontext_get_pc(ctx);
1256 #elif defined(BSD)
1257 return Bsd::ucontext_get_pc(ctx);
1258 #elif defined(LINUX)
1259 return Linux::ucontext_get_pc(ctx);
1260 #elif defined(SOLARIS)
1261 return Solaris::ucontext_get_pc(ctx);
1262 #else
1263 VMError::report_and_die("unimplemented ucontext_get_pc");
1264 #endif
1265 }
1266
1267 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1268 #if defined(AIX)
1269 Aix::ucontext_set_pc(ctx, pc);
1270 #elif defined(BSD)
1271 Bsd::ucontext_set_pc(ctx, pc);
1272 #elif defined(LINUX)
1273 Linux::ucontext_set_pc(ctx, pc);
1274 #elif defined(SOLARIS)
1275 Solaris::ucontext_set_pc(ctx, pc);
1276 #else
1277 VMError::report_and_die("unimplemented ucontext_get_pc");
1278 #endif
1279 }
1280
1281 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1282 size_t stack_size = 0;
1283 size_t guard_size = 0;
1284 int detachstate = 0;
1285 pthread_attr_getstacksize(attr, &stack_size);
1286 pthread_attr_getguardsize(attr, &guard_size);
1287 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1288 LINUX_ONLY(stack_size -= guard_size);
1289 pthread_attr_getdetachstate(attr, &detachstate);
1290 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1291 stack_size / 1024, guard_size / 1024,
1292 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1293 return buf;
1294 }
1295
1296 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1297
1298 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1299 assert(false, "os::Posix::realpath: invalid arguments.");
1300 errno = EINVAL;
1301 return NULL;
1302 }
1303
1304 char* result = NULL;
1305
1306 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1307 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1308 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1309 char* p = ::realpath(filename, NULL);
1310 if (p != NULL) {
1311 if (strlen(p) < outbuflen) {
1312 strcpy(outbuf, p);
1313 result = outbuf;
1314 } else {
1315 errno = ENAMETOOLONG;
1316 }
1317 ::free(p); // *not* os::free
1318 } else {
1319 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1320 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1321 // that it complains about the NULL we handed down as user buffer.
1322 // In this case, use the user provided buffer but at least check whether realpath caused
1323 // a memory overwrite.
1324 if (errno == EINVAL) {
1325 outbuf[outbuflen - 1] = '\0';
1326 p = ::realpath(filename, outbuf);
1327 if (p != NULL) {
1328 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1329 result = p;
1330 }
1331 }
1332 }
1333 return result;
1334
1335 }
1336
1337
1338 // Check minimum allowable stack sizes for thread creation and to initialize
1339 // the java system classes, including StackOverflowError - depends on page
1340 // size.
1341 // The space needed for frames during startup is platform dependent. It
1342 // depends on word size, platform calling conventions, C frame layout and
1343 // interpreter/C1/C2 design decisions. Therefore this is given in a
1344 // platform (os/cpu) dependent constant.
1345 // To this, space for guard mechanisms is added, which depends on the
1346 // page size which again depends on the concrete system the VM is running
1347 // on. Space for libc guard pages is not included in this size.
1348 jint os::Posix::set_minimum_stack_sizes() {
1349 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1350
1351 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1352 JavaThread::stack_guard_zone_size() +
1353 JavaThread::stack_shadow_zone_size();
1354
1355 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1356 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1357
1358 size_t stack_size_in_bytes = ThreadStackSize * K;
1359 if (stack_size_in_bytes != 0 &&
1360 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1361 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1362 // ThreadStackSize so we go with "Java thread stack size" instead
1363 // of "ThreadStackSize" to be more friendly.
1364 tty->print_cr("\nThe Java thread stack size specified is too small. "
1365 "Specify at least " SIZE_FORMAT "k",
1366 _java_thread_min_stack_allowed / K);
1367 return JNI_ERR;
1368 }
1369
1370 // Make the stack size a multiple of the page size so that
1371 // the yellow/red zones can be guarded.
1372 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1373
1374 // Reminder: a compiler thread is a Java thread.
1375 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1376 JavaThread::stack_guard_zone_size() +
1377 JavaThread::stack_shadow_zone_size();
1378
1379 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1380 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1381
1382 stack_size_in_bytes = CompilerThreadStackSize * K;
1383 if (stack_size_in_bytes != 0 &&
1384 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1385 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1386 "Specify at least " SIZE_FORMAT "k",
1387 _compiler_thread_min_stack_allowed / K);
1388 return JNI_ERR;
1389 }
1390
1391 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1392 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1393
1394 stack_size_in_bytes = VMThreadStackSize * K;
1395 if (stack_size_in_bytes != 0 &&
1396 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1397 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1398 "Specify at least " SIZE_FORMAT "k",
1399 _vm_internal_thread_min_stack_allowed / K);
1400 return JNI_ERR;
1401 }
1402 return JNI_OK;
1403 }
1404
1405 // Called when creating the thread. The minimum stack sizes have already been calculated
1406 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1407 size_t stack_size;
1408 if (req_stack_size == 0) {
1409 stack_size = default_stack_size(thr_type);
1410 } else {
1411 stack_size = req_stack_size;
1412 }
1413
1414 switch (thr_type) {
1415 case os::java_thread:
1416 // Java threads use ThreadStackSize which default value can be
1417 // changed with the flag -Xss
1418 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1419 // no requested size and we have a more specific default value
1420 stack_size = JavaThread::stack_size_at_create();
1421 }
1422 stack_size = MAX2(stack_size,
1423 _java_thread_min_stack_allowed);
1424 break;
1425 case os::compiler_thread:
1426 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1427 // no requested size and we have a more specific default value
1428 stack_size = (size_t)(CompilerThreadStackSize * K);
1429 }
1430 stack_size = MAX2(stack_size,
1431 _compiler_thread_min_stack_allowed);
1432 break;
1433 case os::vm_thread:
1434 case os::pgc_thread:
1435 case os::cgc_thread:
1436 case os::watcher_thread:
1437 default: // presume the unknown thr_type is a VM internal
1438 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1439 // no requested size and we have a more specific default value
1440 stack_size = (size_t)(VMThreadStackSize * K);
1441 }
1442
1443 stack_size = MAX2(stack_size,
1444 _vm_internal_thread_min_stack_allowed);
1445 break;
1446 }
1447
1448 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1449 // Be careful not to round up to 0. Align down in that case.
1450 if (stack_size <= SIZE_MAX - vm_page_size()) {
1451 stack_size = align_up(stack_size, vm_page_size());
1452 } else {
1453 stack_size = align_down(stack_size, vm_page_size());
1454 }
1455
1456 return stack_size;
1457 }
1458
1459 bool os::Posix::is_root(uid_t uid){
1460 return ROOT_UID == uid;
1461 }
1462
1463 bool os::Posix::matches_effective_uid_or_root(uid_t uid) {
1464 return is_root(uid) || geteuid() == uid;
1465 }
1466
1467 bool os::Posix::matches_effective_uid_and_gid_or_root(uid_t uid, gid_t gid) {
1468 return is_root(uid) || (geteuid() == uid && getegid() == gid);
1469 }
1470
1471 Thread* os::ThreadCrashProtection::_protected_thread = NULL;
1472 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL;
1473 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0;
1474
1475 os::ThreadCrashProtection::ThreadCrashProtection() {
1476 }
1477
1478 /*
1479 * See the caveats for this class in os_posix.hpp
1480 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1481 * method and returns false. If none of the signals are raised, returns true.
1482 * The callback is supposed to provide the method that should be protected.
1483 */
1484 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1485 sigset_t saved_sig_mask;
1486
1487 Thread::muxAcquire(&_crash_mux, "CrashProtection");
1488
1489 _protected_thread = Thread::current_or_null();
1490 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread");
1491
1492 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1493 // since on at least some systems (OS X) siglongjmp will restore the mask
1494 // for the process, not the thread
1495 pthread_sigmask(0, NULL, &saved_sig_mask);
1496 if (sigsetjmp(_jmpbuf, 0) == 0) {
1497 // make sure we can see in the signal handler that we have crash protection
1498 // installed
1499 _crash_protection = this;
1500 cb.call();
1501 // and clear the crash protection
1502 _crash_protection = NULL;
1503 _protected_thread = NULL;
1504 Thread::muxRelease(&_crash_mux);
1505 return true;
1506 }
1507 // this happens when we siglongjmp() back
1508 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1509 _crash_protection = NULL;
1510 _protected_thread = NULL;
1511 Thread::muxRelease(&_crash_mux);
1512 return false;
1513 }
1514
1515 void os::ThreadCrashProtection::restore() {
1516 assert(_crash_protection != NULL, "must have crash protection");
1517 siglongjmp(_jmpbuf, 1);
1518 }
1519
1520 void os::ThreadCrashProtection::check_crash_protection(int sig,
1521 Thread* thread) {
1522
1523 if (thread != NULL &&
1524 thread == _protected_thread &&
1525 _crash_protection != NULL) {
1526
1527 if (sig == SIGSEGV || sig == SIGBUS) {
1528 _crash_protection->restore();
1529 }
1530 }
1531 }
1532
1533
1534 // Shared pthread_mutex/cond based PlatformEvent implementation.
1535 // Not currently usable by Solaris.
1536
1537 #ifndef SOLARIS
1538
1539 // Shared condattr object for use with relative timed-waits. Will be associated
1540 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1541 // but otherwise whatever default is used by the platform - generally the
1542 // time-of-day clock.
1543 static pthread_condattr_t _condAttr[1];
1544
1545 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1546 // all systems (e.g. FreeBSD) map the default to "normal".
1547 static pthread_mutexattr_t _mutexAttr[1];
1548
1549 // common basic initialization that is always supported
1550 static void pthread_init_common(void) {
1551 int status;
1552 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1553 fatal("pthread_condattr_init: %s", os::strerror(status));
1554 }
1555 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1556 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1557 }
1558 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1559 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1560 }
1561 }
1562
1563 // Not all POSIX types and API's are available on all notionally "posix"
1564 // platforms. If we have build-time support then we will check for actual
1565 // runtime support via dlopen/dlsym lookup. This allows for running on an
1566 // older OS version compared to the build platform. But if there is no
1567 // build time support then there cannot be any runtime support as we do not
1568 // know what the runtime types would be (for example clockid_t might be an
1569 // int or int64_t).
1570 //
1571 #ifdef SUPPORTS_CLOCK_MONOTONIC
1572
1573 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1574
1575 static int (*_clock_gettime)(clockid_t, struct timespec *);
1576 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1577
1578 static bool _use_clock_monotonic_condattr;
1579
1580 // Determine what POSIX API's are present and do appropriate
1581 // configuration.
1582 void os::Posix::init(void) {
1583
1584 // NOTE: no logging available when this is called. Put logging
1585 // statements in init_2().
1586
1587 // Copied from os::Linux::clock_init(). The duplication is temporary.
1588
1589 // 1. Check for CLOCK_MONOTONIC support.
1590
1591 void* handle = NULL;
1592
1593 // For linux we need librt, for other OS we can find
1594 // this function in regular libc.
1595 #ifdef NEEDS_LIBRT
1596 // We do dlopen's in this particular order due to bug in linux
1597 // dynamic loader (see 6348968) leading to crash on exit.
1598 handle = dlopen("librt.so.1", RTLD_LAZY);
1599 if (handle == NULL) {
1600 handle = dlopen("librt.so", RTLD_LAZY);
1601 }
1602 #endif
1603
1604 if (handle == NULL) {
1605 handle = RTLD_DEFAULT;
1606 }
1607
1608 _clock_gettime = NULL;
1609
1610 int (*clock_getres_func)(clockid_t, struct timespec*) =
1611 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1612 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1613 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1614 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1615 // We assume that if both clock_gettime and clock_getres support
1616 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1617 struct timespec res;
1618 struct timespec tp;
1619 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1620 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1621 // Yes, monotonic clock is supported.
1622 _clock_gettime = clock_gettime_func;
1623 } else {
1624 #ifdef NEEDS_LIBRT
1625 // Close librt if there is no monotonic clock.
1626 if (handle != RTLD_DEFAULT) {
1627 dlclose(handle);
1628 }
1629 #endif
1630 }
1631 }
1632
1633 // 2. Check for pthread_condattr_setclock support.
1634
1635 _pthread_condattr_setclock = NULL;
1636
1637 // libpthread is already loaded.
1638 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1639 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1640 "pthread_condattr_setclock");
1641 if (condattr_setclock_func != NULL) {
1642 _pthread_condattr_setclock = condattr_setclock_func;
1643 }
1644
1645 // Now do general initialization.
1646
1647 pthread_init_common();
1648
1649 int status;
1650 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1651 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1652 if (status == EINVAL) {
1653 _use_clock_monotonic_condattr = false;
1654 warning("Unable to use monotonic clock with relative timed-waits" \
1655 " - changes to the time-of-day clock may have adverse affects");
1656 } else {
1657 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1658 }
1659 } else {
1660 _use_clock_monotonic_condattr = true;
1661 }
1662 } else {
1663 _use_clock_monotonic_condattr = false;
1664 }
1665 }
1666
1667 void os::Posix::init_2(void) {
1668 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1669 (_clock_gettime != NULL ? "" : " not"));
1670 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1671 (_pthread_condattr_setclock != NULL ? "" : " not"));
1672 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1673 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1674 }
1675
1676 #else // !SUPPORTS_CLOCK_MONOTONIC
1677
1678 void os::Posix::init(void) {
1679 pthread_init_common();
1680 }
1681
1682 void os::Posix::init_2(void) {
1683 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1684 log_info(os)("Use of pthread_condattr_setclock is not supported");
1685 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1686 }
1687
1688 #endif // SUPPORTS_CLOCK_MONOTONIC
1689
1690 os::PlatformEvent::PlatformEvent() {
1691 int status = pthread_cond_init(_cond, _condAttr);
1692 assert_status(status == 0, status, "cond_init");
1693 status = pthread_mutex_init(_mutex, _mutexAttr);
1694 assert_status(status == 0, status, "mutex_init");
1695 _event = 0;
1696 _nParked = 0;
1697 }
1698
1699 // Utility to convert the given timeout to an absolute timespec
1700 // (based on the appropriate clock) to use with pthread_cond_timewait.
1701 // The clock queried here must be the clock used to manage the
1702 // timeout of the condition variable.
1703 //
1704 // The passed in timeout value is either a relative time in nanoseconds
1705 // or an absolute time in milliseconds. A relative timeout will be
1706 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1707 // the default time-of-day clock will be used.
1708
1709 // Given time is a 64-bit value and the time_t used in the timespec is
1710 // sometimes a signed-32-bit value we have to watch for overflow if times
1711 // way in the future are given. Further on Solaris versions
1712 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1713 // number of seconds, in abstime, is less than current_time + 100000000.
1714 // As it will be over 20 years before "now + 100000000" will overflow we can
1715 // ignore overflow and just impose a hard-limit on seconds using the value
1716 // of "now + 100000000". This places a limit on the timeout of about 3.17
1717 // years from "now".
1718 //
1719 #define MAX_SECS 100000000
1720
1721 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1722 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1723 // on which clock is being used).
1724 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1725 jlong now_part_sec, jlong unit) {
1726 time_t max_secs = now_sec + MAX_SECS;
1727
1728 jlong seconds = timeout / NANOUNITS;
1729 timeout %= NANOUNITS; // remaining nanos
1730
1731 if (seconds >= MAX_SECS) {
1732 // More seconds than we can add, so pin to max_secs.
1733 abstime->tv_sec = max_secs;
1734 abstime->tv_nsec = 0;
1735 } else {
1736 abstime->tv_sec = now_sec + seconds;
1737 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1738 if (nanos >= NANOUNITS) { // overflow
1739 abstime->tv_sec += 1;
1740 nanos -= NANOUNITS;
1741 }
1742 abstime->tv_nsec = nanos;
1743 }
1744 }
1745
1746 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1747 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1748 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1749 time_t max_secs = now_sec + MAX_SECS;
1750
1751 jlong seconds = deadline / MILLIUNITS;
1752 jlong millis = deadline % MILLIUNITS;
1753
1754 if (seconds >= max_secs) {
1755 // Absolute seconds exceeds allowed max, so pin to max_secs.
1756 abstime->tv_sec = max_secs;
1757 abstime->tv_nsec = 0;
1758 } else {
1759 abstime->tv_sec = seconds;
1760 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1761 }
1762 }
1763
1764 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1765 DEBUG_ONLY(int max_secs = MAX_SECS;)
1766
1767 if (timeout < 0) {
1768 timeout = 0;
1769 }
1770
1771 #ifdef SUPPORTS_CLOCK_MONOTONIC
1772
1773 if (_use_clock_monotonic_condattr && !isAbsolute) {
1774 struct timespec now;
1775 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1776 assert_status(status == 0, status, "clock_gettime");
1777 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1778 DEBUG_ONLY(max_secs += now.tv_sec;)
1779 } else {
1780
1781 #else
1782
1783 { // Match the block scope.
1784
1785 #endif // SUPPORTS_CLOCK_MONOTONIC
1786
1787 // Time-of-day clock is all we can reliably use.
1788 struct timeval now;
1789 int status = gettimeofday(&now, NULL);
1790 assert_status(status == 0, errno, "gettimeofday");
1791 if (isAbsolute) {
1792 unpack_abs_time(abstime, timeout, now.tv_sec);
1793 } else {
1794 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1795 }
1796 DEBUG_ONLY(max_secs += now.tv_sec;)
1797 }
1798
1799 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1800 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1801 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1802 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1803 }
1804
1805 // PlatformEvent
1806 //
1807 // Assumption:
1808 // Only one parker can exist on an event, which is why we allocate
1809 // them per-thread. Multiple unparkers can coexist.
1810 //
1811 // _event serves as a restricted-range semaphore.
1812 // -1 : thread is blocked, i.e. there is a waiter
1813 // 0 : neutral: thread is running or ready,
1814 // could have been signaled after a wait started
1815 // 1 : signaled - thread is running or ready
1816 //
1817 // Having three states allows for some detection of bad usage - see
1818 // comments on unpark().
1819
1820 void os::PlatformEvent::park() { // AKA "down()"
1821 // Transitions for _event:
1822 // -1 => -1 : illegal
1823 // 1 => 0 : pass - return immediately
1824 // 0 => -1 : block; then set _event to 0 before returning
1825
1826 // Invariant: Only the thread associated with the PlatformEvent
1827 // may call park().
1828 assert(_nParked == 0, "invariant");
1829
1830 int v;
1831
1832 // atomically decrement _event
1833 for (;;) {
1834 v = _event;
1835 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1836 }
1837 guarantee(v >= 0, "invariant");
1838
1839 if (v == 0) { // Do this the hard way by blocking ...
1840 int status = pthread_mutex_lock(_mutex);
1841 assert_status(status == 0, status, "mutex_lock");
1842 guarantee(_nParked == 0, "invariant");
1843 ++_nParked;
1844 while (_event < 0) {
1845 // OS-level "spurious wakeups" are ignored
1846 status = pthread_cond_wait(_cond, _mutex);
1847 assert_status(status == 0, status, "cond_wait");
1848 }
1849 --_nParked;
1850
1851 _event = 0;
1852 status = pthread_mutex_unlock(_mutex);
1853 assert_status(status == 0, status, "mutex_unlock");
1854 // Paranoia to ensure our locked and lock-free paths interact
1855 // correctly with each other.
1856 OrderAccess::fence();
1857 }
1858 guarantee(_event >= 0, "invariant");
1859 }
1860
1861 int os::PlatformEvent::park(jlong millis) {
1862 // Transitions for _event:
1863 // -1 => -1 : illegal
1864 // 1 => 0 : pass - return immediately
1865 // 0 => -1 : block; then set _event to 0 before returning
1866
1867 // Invariant: Only the thread associated with the Event/PlatformEvent
1868 // may call park().
1869 assert(_nParked == 0, "invariant");
1870
1871 int v;
1872 // atomically decrement _event
1873 for (;;) {
1874 v = _event;
1875 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1876 }
1877 guarantee(v >= 0, "invariant");
1878
1879 if (v == 0) { // Do this the hard way by blocking ...
1880 struct timespec abst;
1881 // We have to watch for overflow when converting millis to nanos,
1882 // but if millis is that large then we will end up limiting to
1883 // MAX_SECS anyway, so just do that here.
1884 if (millis / MILLIUNITS > MAX_SECS) {
1885 millis = jlong(MAX_SECS) * MILLIUNITS;
1886 }
1887 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1888
1889 int ret = OS_TIMEOUT;
1890 int status = pthread_mutex_lock(_mutex);
1891 assert_status(status == 0, status, "mutex_lock");
1892 guarantee(_nParked == 0, "invariant");
1893 ++_nParked;
1894
1895 while (_event < 0) {
1896 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1897 assert_status(status == 0 || status == ETIMEDOUT,
1898 status, "cond_timedwait");
1899 // OS-level "spurious wakeups" are ignored unless the archaic
1900 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1901 if (!FilterSpuriousWakeups) break;
1902 if (status == ETIMEDOUT) break;
1903 }
1904 --_nParked;
1905
1906 if (_event >= 0) {
1907 ret = OS_OK;
1908 }
1909
1910 _event = 0;
1911 status = pthread_mutex_unlock(_mutex);
1912 assert_status(status == 0, status, "mutex_unlock");
1913 // Paranoia to ensure our locked and lock-free paths interact
1914 // correctly with each other.
1915 OrderAccess::fence();
1916 return ret;
1917 }
1918 return OS_OK;
1919 }
1920
1921 void os::PlatformEvent::unpark() {
1922 // Transitions for _event:
1923 // 0 => 1 : just return
1924 // 1 => 1 : just return
1925 // -1 => either 0 or 1; must signal target thread
1926 // That is, we can safely transition _event from -1 to either
1927 // 0 or 1.
1928 // See also: "Semaphores in Plan 9" by Mullender & Cox
1929 //
1930 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1931 // that it will take two back-to-back park() calls for the owning
1932 // thread to block. This has the benefit of forcing a spurious return
1933 // from the first park() call after an unpark() call which will help
1934 // shake out uses of park() and unpark() without checking state conditions
1935 // properly. This spurious return doesn't manifest itself in any user code
1936 // but only in the correctly written condition checking loops of ObjectMonitor,
1937 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1938
1939 if (Atomic::xchg(1, &_event) >= 0) return;
1940
1941 int status = pthread_mutex_lock(_mutex);
1942 assert_status(status == 0, status, "mutex_lock");
1943 int anyWaiters = _nParked;
1944 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1945 status = pthread_mutex_unlock(_mutex);
1946 assert_status(status == 0, status, "mutex_unlock");
1947
1948 // Note that we signal() *after* dropping the lock for "immortal" Events.
1949 // This is safe and avoids a common class of futile wakeups. In rare
1950 // circumstances this can cause a thread to return prematurely from
1951 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1952 // will simply re-test the condition and re-park itself.
1953 // This provides particular benefit if the underlying platform does not
1954 // provide wait morphing.
1955
1956 if (anyWaiters != 0) {
1957 status = pthread_cond_signal(_cond);
1958 assert_status(status == 0, status, "cond_signal");
1959 }
1960 }
1961
1962 // JSR166 support
1963
1964 os::PlatformParker::PlatformParker() {
1965 int status;
1966 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
1967 assert_status(status == 0, status, "cond_init rel");
1968 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
1969 assert_status(status == 0, status, "cond_init abs");
1970 status = pthread_mutex_init(_mutex, _mutexAttr);
1971 assert_status(status == 0, status, "mutex_init");
1972 _cur_index = -1; // mark as unused
1973 }
1974
1975 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
1976 // sets count to 1 and signals condvar. Only one thread ever waits
1977 // on the condvar. Contention seen when trying to park implies that someone
1978 // is unparking you, so don't wait. And spurious returns are fine, so there
1979 // is no need to track notifications.
1980
1981 void Parker::park(bool isAbsolute, jlong time) {
1982
1983 // Optional fast-path check:
1984 // Return immediately if a permit is available.
1985 // We depend on Atomic::xchg() having full barrier semantics
1986 // since we are doing a lock-free update to _counter.
1987 if (Atomic::xchg(0, &_counter) > 0) return;
1988
1989 Thread* thread = Thread::current();
1990 assert(thread->is_Java_thread(), "Must be JavaThread");
1991 JavaThread *jt = (JavaThread *)thread;
1992
1993 // Optional optimization -- avoid state transitions if there's
1994 // an interrupt pending.
1995 if (Thread::is_interrupted(thread, false)) {
1996 return;
1997 }
1998
1999 // Next, demultiplex/decode time arguments
2000 struct timespec absTime;
2001 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
2002 return;
2003 }
2004 if (time > 0) {
2005 to_abstime(&absTime, time, isAbsolute);
2006 }
2007
2008 // Enter safepoint region
2009 // Beware of deadlocks such as 6317397.
2010 // The per-thread Parker:: mutex is a classic leaf-lock.
2011 // In particular a thread must never block on the Threads_lock while
2012 // holding the Parker:: mutex. If safepoints are pending both the
2013 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
2014 ThreadBlockInVM tbivm(jt);
2015
2016 // Don't wait if cannot get lock since interference arises from
2017 // unparking. Also re-check interrupt before trying wait.
2018 if (Thread::is_interrupted(thread, false) ||
2019 pthread_mutex_trylock(_mutex) != 0) {
2020 return;
2021 }
2022
2023 int status;
2024 if (_counter > 0) { // no wait needed
2025 _counter = 0;
2026 status = pthread_mutex_unlock(_mutex);
2027 assert_status(status == 0, status, "invariant");
2028 // Paranoia to ensure our locked and lock-free paths interact
2029 // correctly with each other and Java-level accesses.
2030 OrderAccess::fence();
2031 return;
2032 }
2033
2034 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2035 jt->set_suspend_equivalent();
2036 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2037
2038 assert(_cur_index == -1, "invariant");
2039 if (time == 0) {
2040 _cur_index = REL_INDEX; // arbitrary choice when not timed
2041 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
2042 assert_status(status == 0, status, "cond_timedwait");
2043 }
2044 else {
2045 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
2046 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
2047 assert_status(status == 0 || status == ETIMEDOUT,
2048 status, "cond_timedwait");
2049 }
2050 _cur_index = -1;
2051
2052 _counter = 0;
2053 status = pthread_mutex_unlock(_mutex);
2054 assert_status(status == 0, status, "invariant");
2055 // Paranoia to ensure our locked and lock-free paths interact
2056 // correctly with each other and Java-level accesses.
2057 OrderAccess::fence();
2058
2059 // If externally suspended while waiting, re-suspend
2060 if (jt->handle_special_suspend_equivalent_condition()) {
2061 jt->java_suspend_self();
2062 }
2063 }
2064
2065 void Parker::unpark() {
2066 int status = pthread_mutex_lock(_mutex);
2067 assert_status(status == 0, status, "invariant");
2068 const int s = _counter;
2069 _counter = 1;
2070 // must capture correct index before unlocking
2071 int index = _cur_index;
2072 status = pthread_mutex_unlock(_mutex);
2073 assert_status(status == 0, status, "invariant");
2074
2075 // Note that we signal() *after* dropping the lock for "immortal" Events.
2076 // This is safe and avoids a common class of futile wakeups. In rare
2077 // circumstances this can cause a thread to return prematurely from
2078 // cond_{timed}wait() but the spurious wakeup is benign and the victim
2079 // will simply re-test the condition and re-park itself.
2080 // This provides particular benefit if the underlying platform does not
2081 // provide wait morphing.
2082
2083 if (s < 1 && index != -1) {
2084 // thread is definitely parked
2085 status = pthread_cond_signal(&_cond[index]);
2086 assert_status(status == 0, status, "invariant");
2087 }
2088 }
2089
2090
2091 #endif // !SOLARIS
--- EOF ---