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 <dirent.h>
39 #include <dlfcn.h>
40 #include <pthread.h>
41 #include <signal.h>
42 #include <sys/mman.h>
43 #include <sys/resource.h>
44 #include <sys/utsname.h>
45 #include <time.h>
46 #include <unistd.h>
47
48 // Todo: provide a os::get_max_process_id() or similar. Number of processes
49 // may have been configured, can be read more accurately from proc fs etc.
50 #ifndef MAX_PID
51 #define MAX_PID INT_MAX
52 #endif
53 #define IS_VALID_PID(p) (p > 0 && p < MAX_PID)
54
55 #define ROOT_UID 0
56
57 #ifndef MAP_ANONYMOUS
58 #define MAP_ANONYMOUS MAP_ANON
59 #endif
60
61 #define check_with_errno(check_type, cond, msg) \
62 do { \
63 int err = errno; \
64 check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \
65 os::errno_name(err)); \
66 } while (false)
67
68 #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg)
69 #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg)
70
71 // Check core dump limit and report possible place where core can be found
72 void os::check_dump_limit(char* buffer, size_t bufferSize) {
73 if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) {
74 jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line");
75 VMError::record_coredump_status(buffer, false);
76 return;
77 }
78
79 int n;
80 struct rlimit rlim;
81 bool success;
82
83 char core_path[PATH_MAX];
84 n = get_core_path(core_path, PATH_MAX);
85
86 if (n <= 0) {
87 jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id());
88 success = true;
89 #ifdef LINUX
90 } else if (core_path[0] == '"') { // redirect to user process
91 jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path);
92 success = true;
93 #endif
94 } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
95 jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path);
96 success = true;
97 } else {
98 switch(rlim.rlim_cur) {
99 case RLIM_INFINITY:
100 jio_snprintf(buffer, bufferSize, "%s", core_path);
101 success = true;
102 break;
103 case 0:
104 jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again");
105 success = false;
106 break;
107 default:
108 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);
109 success = true;
110 break;
111 }
112 }
113
114 VMError::record_coredump_status(buffer, success);
115 }
116
117 int os::get_native_stack(address* stack, int frames, int toSkip) {
118 int frame_idx = 0;
119 int num_of_frames; // number of frames captured
120 frame fr = os::current_frame();
121 while (fr.pc() && frame_idx < frames) {
122 if (toSkip > 0) {
123 toSkip --;
124 } else {
125 stack[frame_idx ++] = fr.pc();
126 }
127 if (fr.fp() == NULL || fr.cb() != NULL ||
128 fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break;
129
130 if (fr.sender_pc() && !os::is_first_C_frame(&fr)) {
131 fr = os::get_sender_for_C_frame(&fr);
132 } else {
133 break;
134 }
135 }
136 num_of_frames = frame_idx;
137 for (; frame_idx < frames; frame_idx ++) {
138 stack[frame_idx] = NULL;
139 }
140
141 return num_of_frames;
142 }
143
144
145 bool os::unsetenv(const char* name) {
146 assert(name != NULL, "Null pointer");
147 return (::unsetenv(name) == 0);
148 }
149
150 int os::get_last_error() {
151 return errno;
152 }
153
154 size_t os::lasterror(char *buf, size_t len) {
155 if (errno == 0) return 0;
156
157 const char *s = os::strerror(errno);
158 size_t n = ::strlen(s);
159 if (n >= len) {
160 n = len - 1;
161 }
162 ::strncpy(buf, s, n);
163 buf[n] = '\0';
164 return n;
165 }
166
167 bool os::is_debugger_attached() {
168 // not implemented
169 return false;
170 }
171
172 void os::wait_for_keypress_at_exit(void) {
173 // don't do anything on posix platforms
174 return;
175 }
176
177 int os::create_file_for_heap(const char* dir) {
178
179 const char name_template[] = "/jvmheap.XXXXXX";
180
181 char *fullname = (char*)os::malloc((strlen(dir) + strlen(name_template) + 1), mtInternal);
182 if (fullname == NULL) {
183 vm_exit_during_initialization(err_msg("Malloc failed during creation of backing file for heap (%s)", os::strerror(errno)));
184 return -1;
185 }
186 (void)strncpy(fullname, dir, strlen(dir)+1);
187 (void)strncat(fullname, name_template, strlen(name_template));
188
189 os::native_path(fullname);
190
191 sigset_t set, oldset;
192 int ret = sigfillset(&set);
193 assert_with_errno(ret == 0, "sigfillset returned error");
194
195 // set the file creation mask.
196 mode_t file_mode = S_IRUSR | S_IWUSR;
197
198 // create a new file.
199 int fd = mkstemp(fullname);
200
201 if (fd < 0) {
202 warning("Could not create file for heap with template %s", fullname);
203 os::free(fullname);
204 return -1;
205 }
206
207 // delete the name from the filesystem. When 'fd' is closed, the file (and space) will be deleted.
208 ret = unlink(fullname);
209 assert_with_errno(ret == 0, "unlink returned error");
210
211 os::free(fullname);
212 return fd;
213 }
214
215 static char* reserve_mmapped_memory(size_t bytes, char* requested_addr) {
216 char * addr;
217 int flags = MAP_PRIVATE NOT_AIX( | MAP_NORESERVE ) | MAP_ANONYMOUS;
218 if (requested_addr != NULL) {
219 assert((uintptr_t)requested_addr % os::vm_page_size() == 0, "Requested address should be aligned to OS page size");
220 flags |= MAP_FIXED;
221 }
222
223 // Map reserved/uncommitted pages PROT_NONE so we fail early if we
224 // touch an uncommitted page. Otherwise, the read/write might
225 // succeed if we have enough swap space to back the physical page.
226 addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
227 flags, -1, 0);
228
229 if (addr != MAP_FAILED) {
230 MemTracker::record_virtual_memory_reserve((address)addr, bytes, CALLER_PC);
231 return addr;
232 }
233 return NULL;
234 }
235
236 static int util_posix_fallocate(int fd, off_t offset, off_t len) {
237 #ifdef __APPLE__
238 fstore_t store = { F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, len };
239 // First we try to get a continuous chunk of disk space
240 int ret = fcntl(fd, F_PREALLOCATE, &store);
241 if (ret == -1) {
242 // Maybe we are too fragmented, try to allocate non-continuous range
243 store.fst_flags = F_ALLOCATEALL;
244 ret = fcntl(fd, F_PREALLOCATE, &store);
245 }
246 if(ret != -1) {
247 return ftruncate(fd, len);
248 }
249 return -1;
250 #else
251 return posix_fallocate(fd, offset, len);
252 #endif
253 }
254
255 // Map the given address range to the provided file descriptor.
256 char* os::map_memory_to_file(char* base, size_t size, int fd) {
257 assert(fd != -1, "File descriptor is not valid");
258
259 // allocate space for the file
260 int ret = util_posix_fallocate(fd, 0, (off_t)size);
261 if (ret != 0) {
262 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory. error(%d)", ret));
263 return NULL;
264 }
265
266 int prot = PROT_READ | PROT_WRITE;
267 int flags = MAP_SHARED;
268 if (base != NULL) {
269 flags |= MAP_FIXED;
270 }
271 char* addr = (char*)mmap(base, size, prot, flags, fd, 0);
272
273 if (addr == MAP_FAILED) {
274 warning("Failed mmap to file. (%s)", os::strerror(errno));
275 return NULL;
276 }
277 if (base != NULL && addr != base) {
278 if (!os::release_memory(addr, size)) {
279 warning("Could not release memory on unsuccessful file mapping");
280 }
281 return NULL;
282 }
283 return addr;
284 }
285
286 char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) {
287 assert(fd != -1, "File descriptor is not valid");
288 assert(base != NULL, "Base cannot be NULL");
289
290 return map_memory_to_file(base, size, fd);
291 }
292
293 // Multiple threads can race in this code, and can remap over each other with MAP_FIXED,
294 // so on posix, unmap the section at the start and at the end of the chunk that we mapped
295 // rather than unmapping and remapping the whole chunk to get requested alignment.
296 char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) {
297 assert((alignment & (os::vm_allocation_granularity() - 1)) == 0,
298 "Alignment must be a multiple of allocation granularity (page size)");
299 assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned");
300
301 size_t extra_size = size + alignment;
302 assert(extra_size >= size, "overflow, size is too large to allow alignment");
303
304 char* extra_base;
305 if (file_desc != -1) {
306 // For file mapping, we do not call os:reserve_memory(extra_size, NULL, alignment, file_desc) because
307 // we need to deal with shrinking of the file space later when we release extra memory after alignment.
308 // We also cannot called os:reserve_memory() with file_desc set to -1 because on aix we might get SHM memory.
309 // So here to call a helper function while reserve memory for us. After we have a aligned base,
310 // we will replace anonymous mapping with file mapping.
311 extra_base = reserve_mmapped_memory(extra_size, NULL);
312 if (extra_base != NULL) {
313 MemTracker::record_virtual_memory_reserve((address)extra_base, extra_size, CALLER_PC);
314 }
315 } else {
316 extra_base = os::reserve_memory(extra_size, NULL, alignment);
317 }
318
319 if (extra_base == NULL) {
320 return NULL;
321 }
322
323 // Do manual alignment
324 char* aligned_base = align_up(extra_base, alignment);
325
326 // [ | | ]
327 // ^ extra_base
328 // ^ extra_base + begin_offset == aligned_base
329 // extra_base + begin_offset + size ^
330 // extra_base + extra_size ^
331 // |<>| == begin_offset
332 // end_offset == |<>|
333 size_t begin_offset = aligned_base - extra_base;
334 size_t end_offset = (extra_base + extra_size) - (aligned_base + size);
335
336 if (begin_offset > 0) {
337 os::release_memory(extra_base, begin_offset);
338 }
339
340 if (end_offset > 0) {
341 os::release_memory(extra_base + begin_offset + size, end_offset);
342 }
343
344 if (file_desc != -1) {
345 // After we have an aligned address, we can replace anonymous mapping with file mapping
346 if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) {
347 vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory"));
348 }
349 MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC);
350 }
351 return aligned_base;
352 }
353
354 int os::vsnprintf(char* buf, size_t len, const char* fmt, va_list args) {
355 // All supported POSIX platforms provide C99 semantics.
356 int result = ::vsnprintf(buf, len, fmt, args);
357 // If an encoding error occurred (result < 0) then it's not clear
358 // whether the buffer is NUL terminated, so ensure it is.
359 if ((result < 0) && (len > 0)) {
360 buf[len - 1] = '\0';
361 }
362 return result;
363 }
364
365 int os::get_fileno(FILE* fp) {
366 return NOT_AIX(::)fileno(fp);
367 }
368
369 struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) {
370 return gmtime_r(clock, res);
371 }
372
373 void os::Posix::print_load_average(outputStream* st) {
374 st->print("load average:");
375 double loadavg[3];
376 os::loadavg(loadavg, 3);
377 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
378 st->cr();
379 }
380
381 void os::Posix::print_rlimit_info(outputStream* st) {
382 st->print("rlimit:");
383 struct rlimit rlim;
384
385 st->print(" STACK ");
386 getrlimit(RLIMIT_STACK, &rlim);
387 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
388 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
389
390 st->print(", CORE ");
391 getrlimit(RLIMIT_CORE, &rlim);
392 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
393 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
394
395 // Isn't there on solaris
396 #if defined(AIX)
397 st->print(", NPROC ");
398 st->print("%d", sysconf(_SC_CHILD_MAX));
399 #elif !defined(SOLARIS)
400 st->print(", NPROC ");
401 getrlimit(RLIMIT_NPROC, &rlim);
402 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
403 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
404 #endif
405
406 st->print(", NOFILE ");
407 getrlimit(RLIMIT_NOFILE, &rlim);
408 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
409 else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur));
410
411 st->print(", AS ");
412 getrlimit(RLIMIT_AS, &rlim);
413 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
414 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
415
416 st->print(", DATA ");
417 getrlimit(RLIMIT_DATA, &rlim);
418 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
419 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
420
421 st->print(", FSIZE ");
422 getrlimit(RLIMIT_FSIZE, &rlim);
423 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
424 else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024);
425
426 st->cr();
427 }
428
429 void os::Posix::print_uname_info(outputStream* st) {
430 // kernel
431 st->print("uname:");
432 struct utsname name;
433 uname(&name);
434 st->print("%s ", name.sysname);
435 #ifdef ASSERT
436 st->print("%s ", name.nodename);
437 #endif
438 st->print("%s ", name.release);
439 st->print("%s ", name.version);
440 st->print("%s", name.machine);
441 st->cr();
442 }
443
444 bool os::get_host_name(char* buf, size_t buflen) {
445 struct utsname name;
446 uname(&name);
447 jio_snprintf(buf, buflen, "%s", name.nodename);
448 return true;
449 }
450
451 bool os::has_allocatable_memory_limit(julong* limit) {
452 struct rlimit rlim;
453 int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
454 // if there was an error when calling getrlimit, assume that there is no limitation
455 // on virtual memory.
456 bool result;
457 if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
458 result = false;
459 } else {
460 *limit = (julong)rlim.rlim_cur;
461 result = true;
462 }
463 #ifdef _LP64
464 return result;
465 #else
466 // arbitrary virtual space limit for 32 bit Unices found by testing. If
467 // getrlimit above returned a limit, bound it with this limit. Otherwise
468 // directly use it.
469 const julong max_virtual_limit = (julong)3800*M;
470 if (result) {
471 *limit = MIN2(*limit, max_virtual_limit);
472 } else {
473 *limit = max_virtual_limit;
474 }
475
476 // bound by actually allocatable memory. The algorithm uses two bounds, an
477 // upper and a lower limit. The upper limit is the current highest amount of
478 // memory that could not be allocated, the lower limit is the current highest
479 // amount of memory that could be allocated.
480 // The algorithm iteratively refines the result by halving the difference
481 // between these limits, updating either the upper limit (if that value could
482 // not be allocated) or the lower limit (if the that value could be allocated)
483 // until the difference between these limits is "small".
484
485 // the minimum amount of memory we care about allocating.
486 const julong min_allocation_size = M;
487
488 julong upper_limit = *limit;
489
490 // first check a few trivial cases
491 if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
492 *limit = upper_limit;
493 } else if (!is_allocatable(min_allocation_size)) {
494 // we found that not even min_allocation_size is allocatable. Return it
495 // anyway. There is no point to search for a better value any more.
496 *limit = min_allocation_size;
497 } else {
498 // perform the binary search.
499 julong lower_limit = min_allocation_size;
500 while ((upper_limit - lower_limit) > min_allocation_size) {
501 julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
502 temp_limit = align_down(temp_limit, min_allocation_size);
503 if (is_allocatable(temp_limit)) {
504 lower_limit = temp_limit;
505 } else {
506 upper_limit = temp_limit;
507 }
508 }
509 *limit = lower_limit;
510 }
511 return true;
512 #endif
513 }
514
515 const char* os::get_current_directory(char *buf, size_t buflen) {
516 return getcwd(buf, buflen);
517 }
518
519 FILE* os::open(int fd, const char* mode) {
520 return ::fdopen(fd, mode);
521 }
522
523 void os::flockfile(FILE* fp) {
524 ::flockfile(fp);
525 }
526
527 void os::funlockfile(FILE* fp) {
528 ::funlockfile(fp);
529 }
530
531 DIR* os::opendir(const char* dirname) {
532 assert(dirname != NULL, "just checking");
533 return ::opendir(dirname);
534 }
535
536 struct dirent* os::readdir(DIR* dirp) {
537 assert(dirp != NULL, "just checking");
538 return ::readdir(dirp);
539 }
540
541 int os::closedir(DIR *dirp) {
542 assert(dirp != NULL, "just checking");
543 return ::closedir(dirp);
544 }
545
546 // Builds a platform dependent Agent_OnLoad_<lib_name> function name
547 // which is used to find statically linked in agents.
548 // Parameters:
549 // sym_name: Symbol in library we are looking for
550 // lib_name: Name of library to look in, NULL for shared libs.
551 // is_absolute_path == true if lib_name is absolute path to agent
552 // such as "/a/b/libL.so"
553 // == false if only the base name of the library is passed in
554 // such as "L"
555 char* os::build_agent_function_name(const char *sym_name, const char *lib_name,
556 bool is_absolute_path) {
557 char *agent_entry_name;
558 size_t len;
559 size_t name_len;
560 size_t prefix_len = strlen(JNI_LIB_PREFIX);
561 size_t suffix_len = strlen(JNI_LIB_SUFFIX);
562 const char *start;
563
564 if (lib_name != NULL) {
565 name_len = strlen(lib_name);
566 if (is_absolute_path) {
567 // Need to strip path, prefix and suffix
568 if ((start = strrchr(lib_name, *os::file_separator())) != NULL) {
569 lib_name = ++start;
570 }
571 if (strlen(lib_name) <= (prefix_len + suffix_len)) {
572 return NULL;
573 }
574 lib_name += prefix_len;
575 name_len = strlen(lib_name) - suffix_len;
576 }
577 }
578 len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2;
579 agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread);
580 if (agent_entry_name == NULL) {
581 return NULL;
582 }
583 strcpy(agent_entry_name, sym_name);
584 if (lib_name != NULL) {
585 strcat(agent_entry_name, "_");
586 strncat(agent_entry_name, lib_name, name_len);
587 }
588 return agent_entry_name;
589 }
590
591 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
592 assert(thread == Thread::current(), "thread consistency check");
593
594 ParkEvent * const slp = thread->_SleepEvent ;
595 slp->reset() ;
596 OrderAccess::fence() ;
597
598 if (interruptible) {
599 jlong prevtime = javaTimeNanos();
600
601 for (;;) {
602 if (os::is_interrupted(thread, true)) {
603 return OS_INTRPT;
604 }
605
606 jlong newtime = javaTimeNanos();
607
608 if (newtime - prevtime < 0) {
609 // time moving backwards, should only happen if no monotonic clock
610 // not a guarantee() because JVM should not abort on kernel/glibc bugs
611 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)");
612 } else {
613 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
614 }
615
616 if (millis <= 0) {
617 return OS_OK;
618 }
619
620 prevtime = newtime;
621
622 {
623 assert(thread->is_Java_thread(), "sanity check");
624 JavaThread *jt = (JavaThread *) thread;
625 ThreadBlockInVM tbivm(jt);
626 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
627
628 jt->set_suspend_equivalent();
629 // cleared by handle_special_suspend_equivalent_condition() or
630 // java_suspend_self() via check_and_wait_while_suspended()
631
632 slp->park(millis);
633
634 // were we externally suspended while we were waiting?
635 jt->check_and_wait_while_suspended();
636 }
637 }
638 } else {
639 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
640 jlong prevtime = javaTimeNanos();
641
642 for (;;) {
643 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
644 // the 1st iteration ...
645 jlong newtime = javaTimeNanos();
646
647 if (newtime - prevtime < 0) {
648 // time moving backwards, should only happen if no monotonic clock
649 // not a guarantee() because JVM should not abort on kernel/glibc bugs
650 assert(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)");
651 } else {
652 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
653 }
654
655 if (millis <= 0) break ;
656
657 prevtime = newtime;
658 slp->park(millis);
659 }
660 return OS_OK ;
661 }
662 }
663
664 ////////////////////////////////////////////////////////////////////////////////
665 // interrupt support
666
667 void os::interrupt(Thread* thread) {
668 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
669
670 OSThread* osthread = thread->osthread();
671
672 if (!osthread->interrupted()) {
673 osthread->set_interrupted(true);
674 // More than one thread can get here with the same value of osthread,
675 // resulting in multiple notifications. We do, however, want the store
676 // to interrupted() to be visible to other threads before we execute unpark().
677 OrderAccess::fence();
678 ParkEvent * const slp = thread->_SleepEvent ;
679 if (slp != NULL) slp->unpark() ;
680 }
681
682 // For JSR166. Unpark even if interrupt status already was set
683 if (thread->is_Java_thread())
684 ((JavaThread*)thread)->parker()->unpark();
685
686 ParkEvent * ev = thread->_ParkEvent ;
687 if (ev != NULL) ev->unpark() ;
688 }
689
690 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
691 debug_only(Thread::check_for_dangling_thread_pointer(thread);)
692
693 OSThread* osthread = thread->osthread();
694
695 bool interrupted = osthread->interrupted();
696
697 // NOTE that since there is no "lock" around the interrupt and
698 // is_interrupted operations, there is the possibility that the
699 // interrupted flag (in osThread) will be "false" but that the
700 // low-level events will be in the signaled state. This is
701 // intentional. The effect of this is that Object.wait() and
702 // LockSupport.park() will appear to have a spurious wakeup, which
703 // is allowed and not harmful, and the possibility is so rare that
704 // it is not worth the added complexity to add yet another lock.
705 // For the sleep event an explicit reset is performed on entry
706 // to os::sleep, so there is no early return. It has also been
707 // recommended not to put the interrupted flag into the "event"
708 // structure because it hides the issue.
709 if (interrupted && clear_interrupted) {
710 osthread->set_interrupted(false);
711 // consider thread->_SleepEvent->reset() ... optional optimization
712 }
713
714 return interrupted;
715 }
716
717
718
719 static const struct {
720 int sig; const char* name;
721 }
722 g_signal_info[] =
723 {
724 { SIGABRT, "SIGABRT" },
725 #ifdef SIGAIO
726 { SIGAIO, "SIGAIO" },
727 #endif
728 { SIGALRM, "SIGALRM" },
729 #ifdef SIGALRM1
730 { SIGALRM1, "SIGALRM1" },
731 #endif
732 { SIGBUS, "SIGBUS" },
733 #ifdef SIGCANCEL
734 { SIGCANCEL, "SIGCANCEL" },
735 #endif
736 { SIGCHLD, "SIGCHLD" },
737 #ifdef SIGCLD
738 { SIGCLD, "SIGCLD" },
739 #endif
740 { SIGCONT, "SIGCONT" },
741 #ifdef SIGCPUFAIL
742 { SIGCPUFAIL, "SIGCPUFAIL" },
743 #endif
744 #ifdef SIGDANGER
745 { SIGDANGER, "SIGDANGER" },
746 #endif
747 #ifdef SIGDIL
748 { SIGDIL, "SIGDIL" },
749 #endif
750 #ifdef SIGEMT
751 { SIGEMT, "SIGEMT" },
752 #endif
753 { SIGFPE, "SIGFPE" },
754 #ifdef SIGFREEZE
755 { SIGFREEZE, "SIGFREEZE" },
756 #endif
757 #ifdef SIGGFAULT
758 { SIGGFAULT, "SIGGFAULT" },
759 #endif
760 #ifdef SIGGRANT
761 { SIGGRANT, "SIGGRANT" },
762 #endif
763 { SIGHUP, "SIGHUP" },
764 { SIGILL, "SIGILL" },
765 { SIGINT, "SIGINT" },
766 #ifdef SIGIO
767 { SIGIO, "SIGIO" },
768 #endif
769 #ifdef SIGIOINT
770 { SIGIOINT, "SIGIOINT" },
771 #endif
772 #ifdef SIGIOT
773 // SIGIOT is there for BSD compatibility, but on most Unices just a
774 // synonym for SIGABRT. The result should be "SIGABRT", not
775 // "SIGIOT".
776 #if (SIGIOT != SIGABRT )
777 { SIGIOT, "SIGIOT" },
778 #endif
779 #endif
780 #ifdef SIGKAP
781 { SIGKAP, "SIGKAP" },
782 #endif
783 { SIGKILL, "SIGKILL" },
784 #ifdef SIGLOST
785 { SIGLOST, "SIGLOST" },
786 #endif
787 #ifdef SIGLWP
788 { SIGLWP, "SIGLWP" },
789 #endif
790 #ifdef SIGLWPTIMER
791 { SIGLWPTIMER, "SIGLWPTIMER" },
792 #endif
793 #ifdef SIGMIGRATE
794 { SIGMIGRATE, "SIGMIGRATE" },
795 #endif
796 #ifdef SIGMSG
797 { SIGMSG, "SIGMSG" },
798 #endif
799 { SIGPIPE, "SIGPIPE" },
800 #ifdef SIGPOLL
801 { SIGPOLL, "SIGPOLL" },
802 #endif
803 #ifdef SIGPRE
804 { SIGPRE, "SIGPRE" },
805 #endif
806 { SIGPROF, "SIGPROF" },
807 #ifdef SIGPTY
808 { SIGPTY, "SIGPTY" },
809 #endif
810 #ifdef SIGPWR
811 { SIGPWR, "SIGPWR" },
812 #endif
813 { SIGQUIT, "SIGQUIT" },
814 #ifdef SIGRECONFIG
815 { SIGRECONFIG, "SIGRECONFIG" },
816 #endif
817 #ifdef SIGRECOVERY
818 { SIGRECOVERY, "SIGRECOVERY" },
819 #endif
820 #ifdef SIGRESERVE
821 { SIGRESERVE, "SIGRESERVE" },
822 #endif
823 #ifdef SIGRETRACT
824 { SIGRETRACT, "SIGRETRACT" },
825 #endif
826 #ifdef SIGSAK
827 { SIGSAK, "SIGSAK" },
828 #endif
829 { SIGSEGV, "SIGSEGV" },
830 #ifdef SIGSOUND
831 { SIGSOUND, "SIGSOUND" },
832 #endif
833 #ifdef SIGSTKFLT
834 { SIGSTKFLT, "SIGSTKFLT" },
835 #endif
836 { SIGSTOP, "SIGSTOP" },
837 { SIGSYS, "SIGSYS" },
838 #ifdef SIGSYSERROR
839 { SIGSYSERROR, "SIGSYSERROR" },
840 #endif
841 #ifdef SIGTALRM
842 { SIGTALRM, "SIGTALRM" },
843 #endif
844 { SIGTERM, "SIGTERM" },
845 #ifdef SIGTHAW
846 { SIGTHAW, "SIGTHAW" },
847 #endif
848 { SIGTRAP, "SIGTRAP" },
849 #ifdef SIGTSTP
850 { SIGTSTP, "SIGTSTP" },
851 #endif
852 { SIGTTIN, "SIGTTIN" },
853 { SIGTTOU, "SIGTTOU" },
854 #ifdef SIGURG
855 { SIGURG, "SIGURG" },
856 #endif
857 { SIGUSR1, "SIGUSR1" },
858 { SIGUSR2, "SIGUSR2" },
859 #ifdef SIGVIRT
860 { SIGVIRT, "SIGVIRT" },
861 #endif
862 { SIGVTALRM, "SIGVTALRM" },
863 #ifdef SIGWAITING
864 { SIGWAITING, "SIGWAITING" },
865 #endif
866 #ifdef SIGWINCH
867 { SIGWINCH, "SIGWINCH" },
868 #endif
869 #ifdef SIGWINDOW
870 { SIGWINDOW, "SIGWINDOW" },
871 #endif
872 { SIGXCPU, "SIGXCPU" },
873 { SIGXFSZ, "SIGXFSZ" },
874 #ifdef SIGXRES
875 { SIGXRES, "SIGXRES" },
876 #endif
877 { -1, NULL }
878 };
879
880 // Returned string is a constant. For unknown signals "UNKNOWN" is returned.
881 const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) {
882
883 const char* ret = NULL;
884
885 #ifdef SIGRTMIN
886 if (sig >= SIGRTMIN && sig <= SIGRTMAX) {
887 if (sig == SIGRTMIN) {
888 ret = "SIGRTMIN";
889 } else if (sig == SIGRTMAX) {
890 ret = "SIGRTMAX";
891 } else {
892 jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN);
893 return out;
894 }
895 }
896 #endif
897
898 if (sig > 0) {
899 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
900 if (g_signal_info[idx].sig == sig) {
901 ret = g_signal_info[idx].name;
902 break;
903 }
904 }
905 }
906
907 if (!ret) {
908 if (!is_valid_signal(sig)) {
909 ret = "INVALID";
910 } else {
911 ret = "UNKNOWN";
912 }
913 }
914
915 if (out && outlen > 0) {
916 strncpy(out, ret, outlen);
917 out[outlen - 1] = '\0';
918 }
919 return out;
920 }
921
922 int os::Posix::get_signal_number(const char* signal_name) {
923 char tmp[30];
924 const char* s = signal_name;
925 if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') {
926 jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name);
927 s = tmp;
928 }
929 for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) {
930 if (strcmp(g_signal_info[idx].name, s) == 0) {
931 return g_signal_info[idx].sig;
932 }
933 }
934 return -1;
935 }
936
937 int os::get_signal_number(const char* signal_name) {
938 return os::Posix::get_signal_number(signal_name);
939 }
940
941 // Returns true if signal number is valid.
942 bool os::Posix::is_valid_signal(int sig) {
943 // MacOS not really POSIX compliant: sigaddset does not return
944 // an error for invalid signal numbers. However, MacOS does not
945 // support real time signals and simply seems to have just 33
946 // signals with no holes in the signal range.
947 #ifdef __APPLE__
948 return sig >= 1 && sig < NSIG;
949 #else
950 // Use sigaddset to check for signal validity.
951 sigset_t set;
952 sigemptyset(&set);
953 if (sigaddset(&set, sig) == -1 && errno == EINVAL) {
954 return false;
955 }
956 return true;
957 #endif
958 }
959
960 bool os::Posix::is_sig_ignored(int sig) {
961 struct sigaction oact;
962 sigaction(sig, (struct sigaction*)NULL, &oact);
963 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
964 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
965 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN)) {
966 return true;
967 } else {
968 return false;
969 }
970 }
971
972 // Returns:
973 // NULL for an invalid signal number
974 // "SIG<num>" for a valid but unknown signal number
975 // signal name otherwise.
976 const char* os::exception_name(int sig, char* buf, size_t size) {
977 if (!os::Posix::is_valid_signal(sig)) {
978 return NULL;
979 }
980 const char* const name = os::Posix::get_signal_name(sig, buf, size);
981 if (strcmp(name, "UNKNOWN") == 0) {
982 jio_snprintf(buf, size, "SIG%d", sig);
983 }
984 return buf;
985 }
986
987 #define NUM_IMPORTANT_SIGS 32
988 // Returns one-line short description of a signal set in a user provided buffer.
989 const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) {
990 assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size");
991 // Note: for shortness, just print out the first 32. That should
992 // cover most of the useful ones, apart from realtime signals.
993 for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) {
994 const int rc = sigismember(set, sig);
995 if (rc == -1 && errno == EINVAL) {
996 buffer[sig-1] = '?';
997 } else {
998 buffer[sig-1] = rc == 0 ? '0' : '1';
999 }
1000 }
1001 buffer[NUM_IMPORTANT_SIGS] = 0;
1002 return buffer;
1003 }
1004
1005 // Prints one-line description of a signal set.
1006 void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) {
1007 char buf[NUM_IMPORTANT_SIGS + 1];
1008 os::Posix::describe_signal_set_short(set, buf, sizeof(buf));
1009 st->print("%s", buf);
1010 }
1011
1012 // Writes one-line description of a combination of sigaction.sa_flags into a user
1013 // provided buffer. Returns that buffer.
1014 const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) {
1015 char* p = buffer;
1016 size_t remaining = size;
1017 bool first = true;
1018 int idx = 0;
1019
1020 assert(buffer, "invalid argument");
1021
1022 if (size == 0) {
1023 return buffer;
1024 }
1025
1026 strncpy(buffer, "none", size);
1027
1028 const struct {
1029 // NB: i is an unsigned int here because SA_RESETHAND is on some
1030 // systems 0x80000000, which is implicitly unsigned. Assignining
1031 // it to an int field would be an overflow in unsigned-to-signed
1032 // conversion.
1033 unsigned int i;
1034 const char* s;
1035 } flaginfo [] = {
1036 { SA_NOCLDSTOP, "SA_NOCLDSTOP" },
1037 { SA_ONSTACK, "SA_ONSTACK" },
1038 { SA_RESETHAND, "SA_RESETHAND" },
1039 { SA_RESTART, "SA_RESTART" },
1040 { SA_SIGINFO, "SA_SIGINFO" },
1041 { SA_NOCLDWAIT, "SA_NOCLDWAIT" },
1042 { SA_NODEFER, "SA_NODEFER" },
1043 #ifdef AIX
1044 { SA_ONSTACK, "SA_ONSTACK" },
1045 { SA_OLDSTYLE, "SA_OLDSTYLE" },
1046 #endif
1047 { 0, NULL }
1048 };
1049
1050 for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
1051 if (flags & flaginfo[idx].i) {
1052 if (first) {
1053 jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
1054 first = false;
1055 } else {
1056 jio_snprintf(p, remaining, "|%s", flaginfo[idx].s);
1057 }
1058 const size_t len = strlen(p);
1059 p += len;
1060 remaining -= len;
1061 }
1062 }
1063
1064 buffer[size - 1] = '\0';
1065
1066 return buffer;
1067 }
1068
1069 // Prints one-line description of a combination of sigaction.sa_flags.
1070 void os::Posix::print_sa_flags(outputStream* st, int flags) {
1071 char buffer[0x100];
1072 os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer));
1073 st->print("%s", buffer);
1074 }
1075
1076 // Helper function for os::Posix::print_siginfo_...():
1077 // return a textual description for signal code.
1078 struct enum_sigcode_desc_t {
1079 const char* s_name;
1080 const char* s_desc;
1081 };
1082
1083 static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) {
1084
1085 const struct {
1086 int sig; int code; const char* s_code; const char* s_desc;
1087 } t1 [] = {
1088 { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." },
1089 { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." },
1090 { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." },
1091 { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." },
1092 { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." },
1093 { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." },
1094 { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." },
1095 { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." },
1096 #if defined(IA64) && defined(LINUX)
1097 { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" },
1098 { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" },
1099 #endif
1100 { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." },
1101 { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." },
1102 { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." },
1103 { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." },
1104 { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." },
1105 { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." },
1106 { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." },
1107 { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." },
1108 { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." },
1109 { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." },
1110 #ifdef AIX
1111 // no explanation found what keyerr would be
1112 { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" },
1113 #endif
1114 #if defined(IA64) && !defined(AIX)
1115 { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" },
1116 #endif
1117 #if defined(__sparc) && defined(SOLARIS)
1118 // define Solaris Sparc M7 ADI SEGV signals
1119 #if !defined(SEGV_ACCADI)
1120 #define SEGV_ACCADI 3
1121 #endif
1122 { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." },
1123 #if !defined(SEGV_ACCDERR)
1124 #define SEGV_ACCDERR 4
1125 #endif
1126 { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." },
1127 #if !defined(SEGV_ACCPERR)
1128 #define SEGV_ACCPERR 5
1129 #endif
1130 { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." },
1131 #endif // defined(__sparc) && defined(SOLARIS)
1132 { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." },
1133 { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." },
1134 { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." },
1135 { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." },
1136 { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." },
1137 { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." },
1138 { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." },
1139 { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." },
1140 { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." },
1141 { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." },
1142 { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." },
1143 #ifdef SIGPOLL
1144 { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." },
1145 { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." },
1146 { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." },
1147 { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." },
1148 { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" },
1149 #endif
1150 { -1, -1, NULL, NULL }
1151 };
1152
1153 // Codes valid in any signal context.
1154 const struct {
1155 int code; const char* s_code; const char* s_desc;
1156 } t2 [] = {
1157 { SI_USER, "SI_USER", "Signal sent by kill()." },
1158 { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." },
1159 { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." },
1160 { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." },
1161 { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." },
1162 // Linux specific
1163 #ifdef SI_TKILL
1164 { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" },
1165 #endif
1166 #ifdef SI_DETHREAD
1167 { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" },
1168 #endif
1169 #ifdef SI_KERNEL
1170 { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." },
1171 #endif
1172 #ifdef SI_SIGIO
1173 { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" },
1174 #endif
1175
1176 #ifdef AIX
1177 { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" },
1178 { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" },
1179 #endif
1180
1181 #ifdef __sun
1182 { SI_NOINFO, "SI_NOINFO", "No signal information" },
1183 { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" },
1184 { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" },
1185 #endif
1186
1187 { -1, NULL, NULL }
1188 };
1189
1190 const char* s_code = NULL;
1191 const char* s_desc = NULL;
1192
1193 for (int i = 0; t1[i].sig != -1; i ++) {
1194 if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) {
1195 s_code = t1[i].s_code;
1196 s_desc = t1[i].s_desc;
1197 break;
1198 }
1199 }
1200
1201 if (s_code == NULL) {
1202 for (int i = 0; t2[i].s_code != NULL; i ++) {
1203 if (t2[i].code == si->si_code) {
1204 s_code = t2[i].s_code;
1205 s_desc = t2[i].s_desc;
1206 }
1207 }
1208 }
1209
1210 if (s_code == NULL) {
1211 out->s_name = "unknown";
1212 out->s_desc = "unknown";
1213 return false;
1214 }
1215
1216 out->s_name = s_code;
1217 out->s_desc = s_desc;
1218
1219 return true;
1220 }
1221
1222 void os::print_siginfo(outputStream* os, const void* si0) {
1223
1224 const siginfo_t* const si = (const siginfo_t*) si0;
1225
1226 char buf[20];
1227 os->print("siginfo:");
1228
1229 if (!si) {
1230 os->print(" <null>");
1231 return;
1232 }
1233
1234 const int sig = si->si_signo;
1235
1236 os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf)));
1237
1238 enum_sigcode_desc_t ed;
1239 get_signal_code_description(si, &ed);
1240 os->print(", si_code: %d (%s)", si->si_code, ed.s_name);
1241
1242 if (si->si_errno) {
1243 os->print(", si_errno: %d", si->si_errno);
1244 }
1245
1246 // Output additional information depending on the signal code.
1247
1248 // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions,
1249 // so it depends on the context which member to use. For synchronous error signals,
1250 // we print si_addr, unless the signal was sent by another process or thread, in
1251 // which case we print out pid or tid of the sender.
1252 if (si->si_code == SI_USER || si->si_code == SI_QUEUE) {
1253 const pid_t pid = si->si_pid;
1254 os->print(", si_pid: %ld", (long) pid);
1255 if (IS_VALID_PID(pid)) {
1256 const pid_t me = getpid();
1257 if (me == pid) {
1258 os->print(" (current process)");
1259 }
1260 } else {
1261 os->print(" (invalid)");
1262 }
1263 os->print(", si_uid: %ld", (long) si->si_uid);
1264 if (sig == SIGCHLD) {
1265 os->print(", si_status: %d", si->si_status);
1266 }
1267 } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
1268 sig == SIGTRAP || sig == SIGFPE) {
1269 os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr));
1270 #ifdef SIGPOLL
1271 } else if (sig == SIGPOLL) {
1272 os->print(", si_band: %ld", si->si_band);
1273 #endif
1274 }
1275
1276 }
1277
1278 int os::Posix::unblock_thread_signal_mask(const sigset_t *set) {
1279 return pthread_sigmask(SIG_UNBLOCK, set, NULL);
1280 }
1281
1282 address os::Posix::ucontext_get_pc(const ucontext_t* ctx) {
1283 #if defined(AIX)
1284 return Aix::ucontext_get_pc(ctx);
1285 #elif defined(BSD)
1286 return Bsd::ucontext_get_pc(ctx);
1287 #elif defined(LINUX)
1288 return Linux::ucontext_get_pc(ctx);
1289 #elif defined(SOLARIS)
1290 return Solaris::ucontext_get_pc(ctx);
1291 #else
1292 VMError::report_and_die("unimplemented ucontext_get_pc");
1293 #endif
1294 }
1295
1296 void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) {
1297 #if defined(AIX)
1298 Aix::ucontext_set_pc(ctx, pc);
1299 #elif defined(BSD)
1300 Bsd::ucontext_set_pc(ctx, pc);
1301 #elif defined(LINUX)
1302 Linux::ucontext_set_pc(ctx, pc);
1303 #elif defined(SOLARIS)
1304 Solaris::ucontext_set_pc(ctx, pc);
1305 #else
1306 VMError::report_and_die("unimplemented ucontext_get_pc");
1307 #endif
1308 }
1309
1310 char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) {
1311 size_t stack_size = 0;
1312 size_t guard_size = 0;
1313 int detachstate = 0;
1314 pthread_attr_getstacksize(attr, &stack_size);
1315 pthread_attr_getguardsize(attr, &guard_size);
1316 // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp.
1317 LINUX_ONLY(stack_size -= guard_size);
1318 pthread_attr_getdetachstate(attr, &detachstate);
1319 jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s",
1320 stack_size / 1024, guard_size / 1024,
1321 (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable"));
1322 return buf;
1323 }
1324
1325 char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) {
1326
1327 if (filename == NULL || outbuf == NULL || outbuflen < 1) {
1328 assert(false, "os::Posix::realpath: invalid arguments.");
1329 errno = EINVAL;
1330 return NULL;
1331 }
1332
1333 char* result = NULL;
1334
1335 // This assumes platform realpath() is implemented according to POSIX.1-2008.
1336 // POSIX.1-2008 allows to specify NULL for the output buffer, in which case
1337 // output buffer is dynamically allocated and must be ::free()'d by the caller.
1338 char* p = ::realpath(filename, NULL);
1339 if (p != NULL) {
1340 if (strlen(p) < outbuflen) {
1341 strcpy(outbuf, p);
1342 result = outbuf;
1343 } else {
1344 errno = ENAMETOOLONG;
1345 }
1346 ::free(p); // *not* os::free
1347 } else {
1348 // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath
1349 // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and
1350 // that it complains about the NULL we handed down as user buffer.
1351 // In this case, use the user provided buffer but at least check whether realpath caused
1352 // a memory overwrite.
1353 if (errno == EINVAL) {
1354 outbuf[outbuflen - 1] = '\0';
1355 p = ::realpath(filename, outbuf);
1356 if (p != NULL) {
1357 guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected.");
1358 result = p;
1359 }
1360 }
1361 }
1362 return result;
1363
1364 }
1365
1366 int os::stat(const char *path, struct stat *sbuf) {
1367 return ::stat(path, sbuf);
1368 }
1369
1370 char * os::native_path(char *path) {
1371 return path;
1372 }
1373
1374 // Check minimum allowable stack sizes for thread creation and to initialize
1375 // the java system classes, including StackOverflowError - depends on page
1376 // size.
1377 // The space needed for frames during startup is platform dependent. It
1378 // depends on word size, platform calling conventions, C frame layout and
1379 // interpreter/C1/C2 design decisions. Therefore this is given in a
1380 // platform (os/cpu) dependent constant.
1381 // To this, space for guard mechanisms is added, which depends on the
1382 // page size which again depends on the concrete system the VM is running
1383 // on. Space for libc guard pages is not included in this size.
1384 jint os::Posix::set_minimum_stack_sizes() {
1385 size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN);
1386
1387 _java_thread_min_stack_allowed = _java_thread_min_stack_allowed +
1388 JavaThread::stack_guard_zone_size() +
1389 JavaThread::stack_shadow_zone_size();
1390
1391 _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size());
1392 _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed);
1393
1394 size_t stack_size_in_bytes = ThreadStackSize * K;
1395 if (stack_size_in_bytes != 0 &&
1396 stack_size_in_bytes < _java_thread_min_stack_allowed) {
1397 // The '-Xss' and '-XX:ThreadStackSize=N' options both set
1398 // ThreadStackSize so we go with "Java thread stack size" instead
1399 // of "ThreadStackSize" to be more friendly.
1400 tty->print_cr("\nThe Java thread stack size specified is too small. "
1401 "Specify at least " SIZE_FORMAT "k",
1402 _java_thread_min_stack_allowed / K);
1403 return JNI_ERR;
1404 }
1405
1406 // Make the stack size a multiple of the page size so that
1407 // the yellow/red zones can be guarded.
1408 JavaThread::set_stack_size_at_create(align_up(stack_size_in_bytes, vm_page_size()));
1409
1410 // Reminder: a compiler thread is a Java thread.
1411 _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed +
1412 JavaThread::stack_guard_zone_size() +
1413 JavaThread::stack_shadow_zone_size();
1414
1415 _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size());
1416 _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed);
1417
1418 stack_size_in_bytes = CompilerThreadStackSize * K;
1419 if (stack_size_in_bytes != 0 &&
1420 stack_size_in_bytes < _compiler_thread_min_stack_allowed) {
1421 tty->print_cr("\nThe CompilerThreadStackSize specified is too small. "
1422 "Specify at least " SIZE_FORMAT "k",
1423 _compiler_thread_min_stack_allowed / K);
1424 return JNI_ERR;
1425 }
1426
1427 _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size());
1428 _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed);
1429
1430 stack_size_in_bytes = VMThreadStackSize * K;
1431 if (stack_size_in_bytes != 0 &&
1432 stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) {
1433 tty->print_cr("\nThe VMThreadStackSize specified is too small. "
1434 "Specify at least " SIZE_FORMAT "k",
1435 _vm_internal_thread_min_stack_allowed / K);
1436 return JNI_ERR;
1437 }
1438 return JNI_OK;
1439 }
1440
1441 // Called when creating the thread. The minimum stack sizes have already been calculated
1442 size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) {
1443 size_t stack_size;
1444 if (req_stack_size == 0) {
1445 stack_size = default_stack_size(thr_type);
1446 } else {
1447 stack_size = req_stack_size;
1448 }
1449
1450 switch (thr_type) {
1451 case os::java_thread:
1452 // Java threads use ThreadStackSize which default value can be
1453 // changed with the flag -Xss
1454 if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) {
1455 // no requested size and we have a more specific default value
1456 stack_size = JavaThread::stack_size_at_create();
1457 }
1458 stack_size = MAX2(stack_size,
1459 _java_thread_min_stack_allowed);
1460 break;
1461 case os::compiler_thread:
1462 if (req_stack_size == 0 && CompilerThreadStackSize > 0) {
1463 // no requested size and we have a more specific default value
1464 stack_size = (size_t)(CompilerThreadStackSize * K);
1465 }
1466 stack_size = MAX2(stack_size,
1467 _compiler_thread_min_stack_allowed);
1468 break;
1469 case os::vm_thread:
1470 case os::pgc_thread:
1471 case os::cgc_thread:
1472 case os::watcher_thread:
1473 default: // presume the unknown thr_type is a VM internal
1474 if (req_stack_size == 0 && VMThreadStackSize > 0) {
1475 // no requested size and we have a more specific default value
1476 stack_size = (size_t)(VMThreadStackSize * K);
1477 }
1478
1479 stack_size = MAX2(stack_size,
1480 _vm_internal_thread_min_stack_allowed);
1481 break;
1482 }
1483
1484 // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size.
1485 // Be careful not to round up to 0. Align down in that case.
1486 if (stack_size <= SIZE_MAX - vm_page_size()) {
1487 stack_size = align_up(stack_size, vm_page_size());
1488 } else {
1489 stack_size = align_down(stack_size, vm_page_size());
1490 }
1491
1492 return stack_size;
1493 }
1494
1495 bool os::Posix::is_root(uid_t uid){
1496 return ROOT_UID == uid;
1497 }
1498
1499 bool os::Posix::matches_effective_uid_or_root(uid_t uid) {
1500 return is_root(uid) || geteuid() == uid;
1501 }
1502
1503 bool os::Posix::matches_effective_uid_and_gid_or_root(uid_t uid, gid_t gid) {
1504 return is_root(uid) || (geteuid() == uid && getegid() == gid);
1505 }
1506
1507 Thread* os::ThreadCrashProtection::_protected_thread = NULL;
1508 os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL;
1509 volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0;
1510
1511 os::ThreadCrashProtection::ThreadCrashProtection() {
1512 }
1513
1514 /*
1515 * See the caveats for this class in os_posix.hpp
1516 * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this
1517 * method and returns false. If none of the signals are raised, returns true.
1518 * The callback is supposed to provide the method that should be protected.
1519 */
1520 bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
1521 sigset_t saved_sig_mask;
1522
1523 Thread::muxAcquire(&_crash_mux, "CrashProtection");
1524
1525 _protected_thread = Thread::current_or_null();
1526 assert(_protected_thread != NULL, "Cannot crash protect a NULL thread");
1527
1528 // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask
1529 // since on at least some systems (OS X) siglongjmp will restore the mask
1530 // for the process, not the thread
1531 pthread_sigmask(0, NULL, &saved_sig_mask);
1532 if (sigsetjmp(_jmpbuf, 0) == 0) {
1533 // make sure we can see in the signal handler that we have crash protection
1534 // installed
1535 _crash_protection = this;
1536 cb.call();
1537 // and clear the crash protection
1538 _crash_protection = NULL;
1539 _protected_thread = NULL;
1540 Thread::muxRelease(&_crash_mux);
1541 return true;
1542 }
1543 // this happens when we siglongjmp() back
1544 pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
1545 _crash_protection = NULL;
1546 _protected_thread = NULL;
1547 Thread::muxRelease(&_crash_mux);
1548 return false;
1549 }
1550
1551 void os::ThreadCrashProtection::restore() {
1552 assert(_crash_protection != NULL, "must have crash protection");
1553 siglongjmp(_jmpbuf, 1);
1554 }
1555
1556 void os::ThreadCrashProtection::check_crash_protection(int sig,
1557 Thread* thread) {
1558
1559 if (thread != NULL &&
1560 thread == _protected_thread &&
1561 _crash_protection != NULL) {
1562
1563 if (sig == SIGSEGV || sig == SIGBUS) {
1564 _crash_protection->restore();
1565 }
1566 }
1567 }
1568
1569
1570 // Shared pthread_mutex/cond based PlatformEvent implementation.
1571 // Not currently usable by Solaris.
1572
1573 #ifndef SOLARIS
1574
1575 // Shared condattr object for use with relative timed-waits. Will be associated
1576 // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes,
1577 // but otherwise whatever default is used by the platform - generally the
1578 // time-of-day clock.
1579 static pthread_condattr_t _condAttr[1];
1580
1581 // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not
1582 // all systems (e.g. FreeBSD) map the default to "normal".
1583 static pthread_mutexattr_t _mutexAttr[1];
1584
1585 // common basic initialization that is always supported
1586 static void pthread_init_common(void) {
1587 int status;
1588 if ((status = pthread_condattr_init(_condAttr)) != 0) {
1589 fatal("pthread_condattr_init: %s", os::strerror(status));
1590 }
1591 if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) {
1592 fatal("pthread_mutexattr_init: %s", os::strerror(status));
1593 }
1594 if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) {
1595 fatal("pthread_mutexattr_settype: %s", os::strerror(status));
1596 }
1597 }
1598
1599 // Not all POSIX types and API's are available on all notionally "posix"
1600 // platforms. If we have build-time support then we will check for actual
1601 // runtime support via dlopen/dlsym lookup. This allows for running on an
1602 // older OS version compared to the build platform. But if there is no
1603 // build time support then there cannot be any runtime support as we do not
1604 // know what the runtime types would be (for example clockid_t might be an
1605 // int or int64_t).
1606 //
1607 #ifdef SUPPORTS_CLOCK_MONOTONIC
1608
1609 // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC
1610
1611 static int (*_clock_gettime)(clockid_t, struct timespec *);
1612 static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t);
1613
1614 static bool _use_clock_monotonic_condattr;
1615
1616 // Determine what POSIX API's are present and do appropriate
1617 // configuration.
1618 void os::Posix::init(void) {
1619
1620 // NOTE: no logging available when this is called. Put logging
1621 // statements in init_2().
1622
1623 // Copied from os::Linux::clock_init(). The duplication is temporary.
1624
1625 // 1. Check for CLOCK_MONOTONIC support.
1626
1627 void* handle = NULL;
1628
1629 // For linux we need librt, for other OS we can find
1630 // this function in regular libc.
1631 #ifdef NEEDS_LIBRT
1632 // We do dlopen's in this particular order due to bug in linux
1633 // dynamic loader (see 6348968) leading to crash on exit.
1634 handle = dlopen("librt.so.1", RTLD_LAZY);
1635 if (handle == NULL) {
1636 handle = dlopen("librt.so", RTLD_LAZY);
1637 }
1638 #endif
1639
1640 if (handle == NULL) {
1641 handle = RTLD_DEFAULT;
1642 }
1643
1644 _clock_gettime = NULL;
1645
1646 int (*clock_getres_func)(clockid_t, struct timespec*) =
1647 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1648 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1649 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1650 if (clock_getres_func != NULL && clock_gettime_func != NULL) {
1651 // We assume that if both clock_gettime and clock_getres support
1652 // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock.
1653 struct timespec res;
1654 struct timespec tp;
1655 if (clock_getres_func(CLOCK_MONOTONIC, &res) == 0 &&
1656 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1657 // Yes, monotonic clock is supported.
1658 _clock_gettime = clock_gettime_func;
1659 } else {
1660 #ifdef NEEDS_LIBRT
1661 // Close librt if there is no monotonic clock.
1662 if (handle != RTLD_DEFAULT) {
1663 dlclose(handle);
1664 }
1665 #endif
1666 }
1667 }
1668
1669 // 2. Check for pthread_condattr_setclock support.
1670
1671 _pthread_condattr_setclock = NULL;
1672
1673 // libpthread is already loaded.
1674 int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) =
1675 (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT,
1676 "pthread_condattr_setclock");
1677 if (condattr_setclock_func != NULL) {
1678 _pthread_condattr_setclock = condattr_setclock_func;
1679 }
1680
1681 // Now do general initialization.
1682
1683 pthread_init_common();
1684
1685 int status;
1686 if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) {
1687 if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) {
1688 if (status == EINVAL) {
1689 _use_clock_monotonic_condattr = false;
1690 warning("Unable to use monotonic clock with relative timed-waits" \
1691 " - changes to the time-of-day clock may have adverse affects");
1692 } else {
1693 fatal("pthread_condattr_setclock: %s", os::strerror(status));
1694 }
1695 } else {
1696 _use_clock_monotonic_condattr = true;
1697 }
1698 } else {
1699 _use_clock_monotonic_condattr = false;
1700 }
1701 }
1702
1703 void os::Posix::init_2(void) {
1704 log_info(os)("Use of CLOCK_MONOTONIC is%s supported",
1705 (_clock_gettime != NULL ? "" : " not"));
1706 log_info(os)("Use of pthread_condattr_setclock is%s supported",
1707 (_pthread_condattr_setclock != NULL ? "" : " not"));
1708 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s",
1709 _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock");
1710 }
1711
1712 #else // !SUPPORTS_CLOCK_MONOTONIC
1713
1714 void os::Posix::init(void) {
1715 pthread_init_common();
1716 }
1717
1718 void os::Posix::init_2(void) {
1719 log_info(os)("Use of CLOCK_MONOTONIC is not supported");
1720 log_info(os)("Use of pthread_condattr_setclock is not supported");
1721 log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock");
1722 }
1723
1724 #endif // SUPPORTS_CLOCK_MONOTONIC
1725
1726 os::PlatformEvent::PlatformEvent() {
1727 int status = pthread_cond_init(_cond, _condAttr);
1728 assert_status(status == 0, status, "cond_init");
1729 status = pthread_mutex_init(_mutex, _mutexAttr);
1730 assert_status(status == 0, status, "mutex_init");
1731 _event = 0;
1732 _nParked = 0;
1733 }
1734
1735 // Utility to convert the given timeout to an absolute timespec
1736 // (based on the appropriate clock) to use with pthread_cond_timewait.
1737 // The clock queried here must be the clock used to manage the
1738 // timeout of the condition variable.
1739 //
1740 // The passed in timeout value is either a relative time in nanoseconds
1741 // or an absolute time in milliseconds. A relative timeout will be
1742 // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute,
1743 // the default time-of-day clock will be used.
1744
1745 // Given time is a 64-bit value and the time_t used in the timespec is
1746 // sometimes a signed-32-bit value we have to watch for overflow if times
1747 // way in the future are given. Further on Solaris versions
1748 // prior to 10 there is a restriction (see cond_timedwait) that the specified
1749 // number of seconds, in abstime, is less than current_time + 100000000.
1750 // As it will be over 20 years before "now + 100000000" will overflow we can
1751 // ignore overflow and just impose a hard-limit on seconds using the value
1752 // of "now + 100000000". This places a limit on the timeout of about 3.17
1753 // years from "now".
1754 //
1755 #define MAX_SECS 100000000
1756
1757 // Calculate a new absolute time that is "timeout" nanoseconds from "now".
1758 // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending
1759 // on which clock is being used).
1760 static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec,
1761 jlong now_part_sec, jlong unit) {
1762 time_t max_secs = now_sec + MAX_SECS;
1763
1764 jlong seconds = timeout / NANOUNITS;
1765 timeout %= NANOUNITS; // remaining nanos
1766
1767 if (seconds >= MAX_SECS) {
1768 // More seconds than we can add, so pin to max_secs.
1769 abstime->tv_sec = max_secs;
1770 abstime->tv_nsec = 0;
1771 } else {
1772 abstime->tv_sec = now_sec + seconds;
1773 long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout;
1774 if (nanos >= NANOUNITS) { // overflow
1775 abstime->tv_sec += 1;
1776 nanos -= NANOUNITS;
1777 }
1778 abstime->tv_nsec = nanos;
1779 }
1780 }
1781
1782 // Unpack the given deadline in milliseconds since the epoch, into the given timespec.
1783 // The current time in seconds is also passed in to enforce an upper bound as discussed above.
1784 static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) {
1785 time_t max_secs = now_sec + MAX_SECS;
1786
1787 jlong seconds = deadline / MILLIUNITS;
1788 jlong millis = deadline % MILLIUNITS;
1789
1790 if (seconds >= max_secs) {
1791 // Absolute seconds exceeds allowed max, so pin to max_secs.
1792 abstime->tv_sec = max_secs;
1793 abstime->tv_nsec = 0;
1794 } else {
1795 abstime->tv_sec = seconds;
1796 abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS);
1797 }
1798 }
1799
1800 static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) {
1801 DEBUG_ONLY(int max_secs = MAX_SECS;)
1802
1803 if (timeout < 0) {
1804 timeout = 0;
1805 }
1806
1807 #ifdef SUPPORTS_CLOCK_MONOTONIC
1808
1809 if (_use_clock_monotonic_condattr && !isAbsolute) {
1810 struct timespec now;
1811 int status = _clock_gettime(CLOCK_MONOTONIC, &now);
1812 assert_status(status == 0, status, "clock_gettime");
1813 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS);
1814 DEBUG_ONLY(max_secs += now.tv_sec;)
1815 } else {
1816
1817 #else
1818
1819 { // Match the block scope.
1820
1821 #endif // SUPPORTS_CLOCK_MONOTONIC
1822
1823 // Time-of-day clock is all we can reliably use.
1824 struct timeval now;
1825 int status = gettimeofday(&now, NULL);
1826 assert_status(status == 0, errno, "gettimeofday");
1827 if (isAbsolute) {
1828 unpack_abs_time(abstime, timeout, now.tv_sec);
1829 } else {
1830 calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS);
1831 }
1832 DEBUG_ONLY(max_secs += now.tv_sec;)
1833 }
1834
1835 assert(abstime->tv_sec >= 0, "tv_sec < 0");
1836 assert(abstime->tv_sec <= max_secs, "tv_sec > max_secs");
1837 assert(abstime->tv_nsec >= 0, "tv_nsec < 0");
1838 assert(abstime->tv_nsec < NANOUNITS, "tv_nsec >= NANOUNITS");
1839 }
1840
1841 // PlatformEvent
1842 //
1843 // Assumption:
1844 // Only one parker can exist on an event, which is why we allocate
1845 // them per-thread. Multiple unparkers can coexist.
1846 //
1847 // _event serves as a restricted-range semaphore.
1848 // -1 : thread is blocked, i.e. there is a waiter
1849 // 0 : neutral: thread is running or ready,
1850 // could have been signaled after a wait started
1851 // 1 : signaled - thread is running or ready
1852 //
1853 // Having three states allows for some detection of bad usage - see
1854 // comments on unpark().
1855
1856 void os::PlatformEvent::park() { // AKA "down()"
1857 // Transitions for _event:
1858 // -1 => -1 : illegal
1859 // 1 => 0 : pass - return immediately
1860 // 0 => -1 : block; then set _event to 0 before returning
1861
1862 // Invariant: Only the thread associated with the PlatformEvent
1863 // may call park().
1864 assert(_nParked == 0, "invariant");
1865
1866 int v;
1867
1868 // atomically decrement _event
1869 for (;;) {
1870 v = _event;
1871 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1872 }
1873 guarantee(v >= 0, "invariant");
1874
1875 if (v == 0) { // Do this the hard way by blocking ...
1876 int status = pthread_mutex_lock(_mutex);
1877 assert_status(status == 0, status, "mutex_lock");
1878 guarantee(_nParked == 0, "invariant");
1879 ++_nParked;
1880 while (_event < 0) {
1881 // OS-level "spurious wakeups" are ignored
1882 status = pthread_cond_wait(_cond, _mutex);
1883 assert_status(status == 0, status, "cond_wait");
1884 }
1885 --_nParked;
1886
1887 _event = 0;
1888 status = pthread_mutex_unlock(_mutex);
1889 assert_status(status == 0, status, "mutex_unlock");
1890 // Paranoia to ensure our locked and lock-free paths interact
1891 // correctly with each other.
1892 OrderAccess::fence();
1893 }
1894 guarantee(_event >= 0, "invariant");
1895 }
1896
1897 int os::PlatformEvent::park(jlong millis) {
1898 // Transitions for _event:
1899 // -1 => -1 : illegal
1900 // 1 => 0 : pass - return immediately
1901 // 0 => -1 : block; then set _event to 0 before returning
1902
1903 // Invariant: Only the thread associated with the Event/PlatformEvent
1904 // may call park().
1905 assert(_nParked == 0, "invariant");
1906
1907 int v;
1908 // atomically decrement _event
1909 for (;;) {
1910 v = _event;
1911 if (Atomic::cmpxchg(v - 1, &_event, v) == v) break;
1912 }
1913 guarantee(v >= 0, "invariant");
1914
1915 if (v == 0) { // Do this the hard way by blocking ...
1916 struct timespec abst;
1917 // We have to watch for overflow when converting millis to nanos,
1918 // but if millis is that large then we will end up limiting to
1919 // MAX_SECS anyway, so just do that here.
1920 if (millis / MILLIUNITS > MAX_SECS) {
1921 millis = jlong(MAX_SECS) * MILLIUNITS;
1922 }
1923 to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
1924
1925 int ret = OS_TIMEOUT;
1926 int status = pthread_mutex_lock(_mutex);
1927 assert_status(status == 0, status, "mutex_lock");
1928 guarantee(_nParked == 0, "invariant");
1929 ++_nParked;
1930
1931 while (_event < 0) {
1932 status = pthread_cond_timedwait(_cond, _mutex, &abst);
1933 assert_status(status == 0 || status == ETIMEDOUT,
1934 status, "cond_timedwait");
1935 // OS-level "spurious wakeups" are ignored unless the archaic
1936 // FilterSpuriousWakeups is set false. That flag should be obsoleted.
1937 if (!FilterSpuriousWakeups) break;
1938 if (status == ETIMEDOUT) break;
1939 }
1940 --_nParked;
1941
1942 if (_event >= 0) {
1943 ret = OS_OK;
1944 }
1945
1946 _event = 0;
1947 status = pthread_mutex_unlock(_mutex);
1948 assert_status(status == 0, status, "mutex_unlock");
1949 // Paranoia to ensure our locked and lock-free paths interact
1950 // correctly with each other.
1951 OrderAccess::fence();
1952 return ret;
1953 }
1954 return OS_OK;
1955 }
1956
1957 void os::PlatformEvent::unpark() {
1958 // Transitions for _event:
1959 // 0 => 1 : just return
1960 // 1 => 1 : just return
1961 // -1 => either 0 or 1; must signal target thread
1962 // That is, we can safely transition _event from -1 to either
1963 // 0 or 1.
1964 // See also: "Semaphores in Plan 9" by Mullender & Cox
1965 //
1966 // Note: Forcing a transition from "-1" to "1" on an unpark() means
1967 // that it will take two back-to-back park() calls for the owning
1968 // thread to block. This has the benefit of forcing a spurious return
1969 // from the first park() call after an unpark() call which will help
1970 // shake out uses of park() and unpark() without checking state conditions
1971 // properly. This spurious return doesn't manifest itself in any user code
1972 // but only in the correctly written condition checking loops of ObjectMonitor,
1973 // Mutex/Monitor, Thread::muxAcquire and os::sleep
1974
1975 if (Atomic::xchg(1, &_event) >= 0) return;
1976
1977 int status = pthread_mutex_lock(_mutex);
1978 assert_status(status == 0, status, "mutex_lock");
1979 int anyWaiters = _nParked;
1980 assert(anyWaiters == 0 || anyWaiters == 1, "invariant");
1981 status = pthread_mutex_unlock(_mutex);
1982 assert_status(status == 0, status, "mutex_unlock");
1983
1984 // Note that we signal() *after* dropping the lock for "immortal" Events.
1985 // This is safe and avoids a common class of futile wakeups. In rare
1986 // circumstances this can cause a thread to return prematurely from
1987 // cond_{timed}wait() but the spurious wakeup is benign and the victim
1988 // will simply re-test the condition and re-park itself.
1989 // This provides particular benefit if the underlying platform does not
1990 // provide wait morphing.
1991
1992 if (anyWaiters != 0) {
1993 status = pthread_cond_signal(_cond);
1994 assert_status(status == 0, status, "cond_signal");
1995 }
1996 }
1997
1998 // JSR166 support
1999
2000 os::PlatformParker::PlatformParker() {
2001 int status;
2002 status = pthread_cond_init(&_cond[REL_INDEX], _condAttr);
2003 assert_status(status == 0, status, "cond_init rel");
2004 status = pthread_cond_init(&_cond[ABS_INDEX], NULL);
2005 assert_status(status == 0, status, "cond_init abs");
2006 status = pthread_mutex_init(_mutex, _mutexAttr);
2007 assert_status(status == 0, status, "mutex_init");
2008 _cur_index = -1; // mark as unused
2009 }
2010
2011 // Parker::park decrements count if > 0, else does a condvar wait. Unpark
2012 // sets count to 1 and signals condvar. Only one thread ever waits
2013 // on the condvar. Contention seen when trying to park implies that someone
2014 // is unparking you, so don't wait. And spurious returns are fine, so there
2015 // is no need to track notifications.
2016
2017 void Parker::park(bool isAbsolute, jlong time) {
2018
2019 // Optional fast-path check:
2020 // Return immediately if a permit is available.
2021 // We depend on Atomic::xchg() having full barrier semantics
2022 // since we are doing a lock-free update to _counter.
2023 if (Atomic::xchg(0, &_counter) > 0) return;
2024
2025 Thread* thread = Thread::current();
2026 assert(thread->is_Java_thread(), "Must be JavaThread");
2027 JavaThread *jt = (JavaThread *)thread;
2028
2029 // Optional optimization -- avoid state transitions if there's
2030 // an interrupt pending.
2031 if (Thread::is_interrupted(thread, false)) {
2032 return;
2033 }
2034
2035 // Next, demultiplex/decode time arguments
2036 struct timespec absTime;
2037 if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all
2038 return;
2039 }
2040 if (time > 0) {
2041 to_abstime(&absTime, time, isAbsolute);
2042 }
2043
2044 // Enter safepoint region
2045 // Beware of deadlocks such as 6317397.
2046 // The per-thread Parker:: mutex is a classic leaf-lock.
2047 // In particular a thread must never block on the Threads_lock while
2048 // holding the Parker:: mutex. If safepoints are pending both the
2049 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
2050 ThreadBlockInVM tbivm(jt);
2051
2052 // Don't wait if cannot get lock since interference arises from
2053 // unparking. Also re-check interrupt before trying wait.
2054 if (Thread::is_interrupted(thread, false) ||
2055 pthread_mutex_trylock(_mutex) != 0) {
2056 return;
2057 }
2058
2059 int status;
2060 if (_counter > 0) { // no wait needed
2061 _counter = 0;
2062 status = pthread_mutex_unlock(_mutex);
2063 assert_status(status == 0, status, "invariant");
2064 // Paranoia to ensure our locked and lock-free paths interact
2065 // correctly with each other and Java-level accesses.
2066 OrderAccess::fence();
2067 return;
2068 }
2069
2070 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2071 jt->set_suspend_equivalent();
2072 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2073
2074 assert(_cur_index == -1, "invariant");
2075 if (time == 0) {
2076 _cur_index = REL_INDEX; // arbitrary choice when not timed
2077 status = pthread_cond_wait(&_cond[_cur_index], _mutex);
2078 assert_status(status == 0, status, "cond_timedwait");
2079 }
2080 else {
2081 _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX;
2082 status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime);
2083 assert_status(status == 0 || status == ETIMEDOUT,
2084 status, "cond_timedwait");
2085 }
2086 _cur_index = -1;
2087
2088 _counter = 0;
2089 status = pthread_mutex_unlock(_mutex);
2090 assert_status(status == 0, status, "invariant");
2091 // Paranoia to ensure our locked and lock-free paths interact
2092 // correctly with each other and Java-level accesses.
2093 OrderAccess::fence();
2094
2095 // If externally suspended while waiting, re-suspend
2096 if (jt->handle_special_suspend_equivalent_condition()) {
2097 jt->java_suspend_self();
2098 }
2099 }
2100
2101 void Parker::unpark() {
2102 int status = pthread_mutex_lock(_mutex);
2103 assert_status(status == 0, status, "invariant");
2104 const int s = _counter;
2105 _counter = 1;
2106 // must capture correct index before unlocking
2107 int index = _cur_index;
2108 status = pthread_mutex_unlock(_mutex);
2109 assert_status(status == 0, status, "invariant");
2110
2111 // Note that we signal() *after* dropping the lock for "immortal" Events.
2112 // This is safe and avoids a common class of futile wakeups. In rare
2113 // circumstances this can cause a thread to return prematurely from
2114 // cond_{timed}wait() but the spurious wakeup is benign and the victim
2115 // will simply re-test the condition and re-park itself.
2116 // This provides particular benefit if the underlying platform does not
2117 // provide wait morphing.
2118
2119 if (s < 1 && index != -1) {
2120 // thread is definitely parked
2121 status = pthread_cond_signal(&_cond[index]);
2122 assert_status(status == 0, status, "invariant");
2123 }
2124 }
2125
2126
2127 #endif // !SOLARIS