1 /*
2 * Copyright (c) 2012, 2020, 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 "precompiled.hpp"
26 #include "jfr/jfrEvents.hpp"
27 #include "jfr/jni/jfrJavaSupport.hpp"
28 #include "jfr/leakprofiler/leakProfiler.hpp"
29 #include "jfr/recorder/repository/jfrEmergencyDump.hpp"
30 #include "jfr/recorder/service/jfrPostBox.hpp"
31 #include "jfr/recorder/service/jfrRecorderService.hpp"
32 #include "jfr/utilities/jfrTypes.hpp"
33 #include "logging/log.hpp"
34 #include "runtime/atomic.hpp"
35 #include "runtime/globals.hpp"
36 #include "runtime/mutexLocker.hpp"
37 #include "runtime/os.hpp"
38 #include "runtime/thread.inline.hpp"
39 #include "utilities/growableArray.hpp"
40 #include "utilities/ostream.hpp"
41
42 static const char vm_error_filename_fmt[] = "hs_err_pid%p.jfr";
43 static const char vm_oom_filename_fmt[] = "hs_oom_pid%p.jfr";
44 static const char vm_soe_filename_fmt[] = "hs_soe_pid%p.jfr";
45 static const char chunk_file_jfr_ext[] = ".jfr";
46 static const size_t iso8601_len = 19; // "YYYY-MM-DDTHH:MM:SS"
47 static fio_fd emergency_fd = invalid_fd;
48 static const int64_t chunk_file_header_size = 68;
49 static const size_t chunk_file_extension_length = sizeof chunk_file_jfr_ext - 1;
50
51 /*
52 * The emergency dump logic is restrictive when it comes to
53 * using internal VM constructs such as ResourceArea / Handle / Arena.
54 * The reason being that the thread context is unknown.
55 *
56 * A single static buffer of size JVM_MAXPATHLEN is used for building paths.
57 * os::malloc / os::free are used in a few places.
58 */
59
60 static const size_t _max_path_buffer_size = JVM_MAXPATHLEN;
61 static char _path_buffer[_max_path_buffer_size] = { 0 };
62
63 static bool is_empty(const char* path) {
64 assert(path != NULL, "invariant");
65 return path[0] == '\0';
66 }
67
68 static bool is_path_empty() {
69 return *_path_buffer == '\0';
70 }
71
72 static size_t append(size_t pos, const char* str) {
73 assert(_max_path_buffer_size - pos > 0, "invariant");
74 const int result = jio_snprintf(_path_buffer + pos, _max_path_buffer_size - pos, "%s", str);
75 return result == -1 ? 0 : pos + (size_t)result;
76 }
77
78 // returns with an appended file separator (if successful)
79 static size_t get_current_directory() {
80 if (os::get_current_directory(_path_buffer, _max_path_buffer_size) == NULL) {
81 return 0;
82 }
83 return append(strlen(_path_buffer), os::file_separator());
84 }
85
86 static fio_fd open_exclusivly(const char* path) {
87 assert(path != NULL, "invariant");
88 assert(!is_empty(path), "invariant");
89 return os::open(path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE);
90 }
91
92 static bool is_emergency_dump_file_open() {
93 return emergency_fd != invalid_fd;
94 }
95
96 static bool open_emergency_dump_fd(const char* path) {
97 if (path == NULL) {
98 return false;
99 }
100 assert(emergency_fd == invalid_fd, "invariant");
101 emergency_fd = open_exclusivly(path);
102 return emergency_fd != invalid_fd;
103 }
104
105 static void close_emergency_dump_file() {
106 if (is_emergency_dump_file_open()) {
107 os::close(emergency_fd);
108 }
109 }
110
111 static const char* create_emergency_dump_path() {
112 assert(is_path_empty(), "invariant");
113
114 const size_t path_len = get_current_directory();
115 if (path_len == 0) {
116 return NULL;
117 }
118 const char* filename_fmt = NULL;
119 // fetch specific error cause
120 switch (JfrJavaSupport::cause()) {
121 case JfrJavaSupport::OUT_OF_MEMORY:
122 filename_fmt = vm_oom_filename_fmt;
123 break;
124 case JfrJavaSupport::STACK_OVERFLOW:
125 filename_fmt = vm_soe_filename_fmt;
126 break;
127 default:
128 filename_fmt = vm_error_filename_fmt;
129 }
130 const bool result = Arguments::copy_expand_pid(filename_fmt, strlen(filename_fmt), _path_buffer + path_len, _max_path_buffer_size - path_len);
131 return result ? _path_buffer : NULL;
132 }
133
134 static bool open_emergency_dump_file() {
135 if (is_emergency_dump_file_open()) {
136 // opened already
137 return true;
138 }
139 return open_emergency_dump_fd(create_emergency_dump_path());
140 }
141
142 static void report(outputStream* st, bool emergency_file_opened, const char* repository_path) {
143 assert(st != NULL, "invariant");
144 if (emergency_file_opened) {
145 st->print_raw("# JFR recording file will be written. Location: ");
146 st->print_raw_cr(_path_buffer);
147 st->print_raw_cr("#");
148 } else if (repository_path != NULL) {
149 st->print_raw("# The JFR repository may contain useful JFR files. Location: ");
150 st->print_raw_cr(repository_path);
151 st->print_raw_cr("#");
152 } else if (!is_path_empty()) {
153 st->print_raw("# Unable to create a JFR recording file at location: ");
154 st->print_raw_cr(_path_buffer);
155 st->print_raw_cr("#");
156 }
157 }
158
159 void JfrEmergencyDump::on_vm_error_report(outputStream* st, const char* repository_path) {
160 assert(st != NULL, "invariant");
161 Thread* thread = Thread::current_or_null_safe();
162 if (thread != NULL) {
163 report(st, open_emergency_dump_file(), repository_path);
164 } else if (repository_path != NULL) {
165 // a non-attached thread will not be able to write anything later
166 report(st, false, repository_path);
167 }
168 }
169
170 static int file_sort(const char** const file1, const char** file2) {
171 assert(NULL != *file1 && NULL != *file2, "invariant");
172 int cmp = strncmp(*file1, *file2, iso8601_len);
173 if (0 == cmp) {
174 const char* const dot1 = strchr(*file1, '.');
175 assert(NULL != dot1, "invariant");
176 const char* const dot2 = strchr(*file2, '.');
177 assert(NULL != dot2, "invariant");
178 ptrdiff_t file1_len = dot1 - *file1;
179 ptrdiff_t file2_len = dot2 - *file2;
180 if (file1_len < file2_len) {
181 return -1;
182 }
183 if (file1_len > file2_len) {
184 return 1;
185 }
186 assert(file1_len == file2_len, "invariant");
187 cmp = strncmp(*file1, *file2, file1_len);
188 }
189 assert(cmp != 0, "invariant");
190 return cmp;
191 }
192
193 static void iso8601_to_date_time(char* iso8601_str) {
194 assert(iso8601_str != NULL, "invariant");
195 assert(strlen(iso8601_str) == iso8601_len, "invariant");
196 // "YYYY-MM-DDTHH:MM:SS"
197 for (size_t i = 0; i < iso8601_len; ++i) {
198 switch (iso8601_str[i]) {
199 case 'T':
200 case '-':
201 case ':':
202 iso8601_str[i] = '_';
203 break;
204 }
205 }
206 // "YYYY_MM_DD_HH_MM_SS"
207 }
208
209 static void date_time(char* buffer, size_t buffer_len) {
210 assert(buffer != NULL, "invariant");
211 assert(buffer_len >= iso8601_len, "buffer too small");
212 os::iso8601_time(buffer, buffer_len);
213 assert(strlen(buffer) >= iso8601_len + 1, "invariant");
214 // "YYYY-MM-DDTHH:MM:SS"
215 buffer[iso8601_len] = '\0';
216 iso8601_to_date_time(buffer);
217 }
218
219 static int64_t file_size(fio_fd fd) {
220 assert(fd != invalid_fd, "invariant");
221 const int64_t current_offset = os::current_file_offset(fd);
222 const int64_t size = os::lseek(fd, 0, SEEK_END);
223 os::seek_to_file_offset(fd, current_offset);
224 return size;
225 }
226
227 class RepositoryIterator : public StackObj {
228 private:
229 GrowableArray<const char*>* _file_names;
230 size_t _path_buffer_file_name_offset;
231 mutable int _iterator;
232 const char* fully_qualified(const char* file_name) const;
233 const char* filter(const char* file_name) const;
234 public:
235 RepositoryIterator(const char* repository_path);
236 ~RepositoryIterator();
237 bool has_next() const;
238 const char* next() const;
239 };
240
241 // append the file_name at the _path_buffer_file_name_offset position
242 const char* RepositoryIterator::fully_qualified(const char* file_name) const {
243 assert(NULL != file_name, "invariant");
244 assert(!is_path_empty(), "invariant");
245 assert(_path_buffer_file_name_offset != 0, "invariant");
246 return append(_path_buffer_file_name_offset, file_name) != 0 ? _path_buffer : NULL;
247 }
248
249 // caller responsible for deallocation
250 const char* RepositoryIterator::filter(const char* file_name) const {
251 if (file_name == NULL) {
252 return NULL;
253 }
254 const size_t len = strlen(file_name);
255 if ((len < chunk_file_extension_length) ||
256 (strncmp(&file_name[len - chunk_file_extension_length],
257 chunk_file_jfr_ext,
258 chunk_file_extension_length) != 0)) {
259 // not a .jfr file
260 return NULL;
261 }
262 const char* fqn = fully_qualified(file_name);
263 if (fqn == NULL) {
264 return NULL;
265 }
266 const fio_fd fd = open_exclusivly(fqn);
267 if (invalid_fd == fd) {
268 return NULL;
269 }
270 const int64_t size = file_size(fd);
271 os::close(fd);
272 if (size <= chunk_file_header_size) {
273 return NULL;
274 }
275 char* const file_name_copy = (char*)os::malloc(len + 1, mtTracing);
276 if (file_name_copy == NULL) {
277 log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
278 return NULL;
279 }
280 strncpy(file_name_copy, file_name, len + 1);
281 return file_name_copy;
282 }
283
284 RepositoryIterator::RepositoryIterator(const char* repository_path) :
285 _file_names(NULL),
286 _path_buffer_file_name_offset(0),
287 _iterator(0) {
288 DIR* dirp = os::opendir(repository_path);
289 if (dirp == NULL) {
290 log_error(jfr, system)("Unable to open repository %s", repository_path);
291 return;
292 }
293 // store repository path in the path buffer
294 size_t result = append(0, repository_path);
295 if (result == 0) {
296 return;
297 }
298 // append a file separator and save that position
299 _path_buffer_file_name_offset = append(result, os::file_separator());
300 if (_path_buffer_file_name_offset == 0) {
301 return;
302 }
303 _file_names = new (ResourceObj::C_HEAP, mtTracing) GrowableArray<const char*>(10, true, mtTracing);
304 if (_file_names == NULL) {
305 log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
306 return;
307 }
308 // iterate files in the repository and append filtered file names to the files array
309 struct dirent* dentry;
310 while ((dentry = os::readdir(dirp)) != NULL) {
311 const char* file_name = filter(dentry->d_name);
312 if (file_name != NULL) {
313 _file_names->append(file_name);
314 }
315 }
316 os::closedir(dirp);
317 if (_file_names->length() > 1) {
318 _file_names->sort(file_sort);
319 }
320 }
321
322 RepositoryIterator::~RepositoryIterator() {
323 if (_file_names != NULL) {
324 for (int i = 0; i < _file_names->length(); ++i) {
325 os::free(const_cast<char*>(_file_names->at(i)));
326 }
327 delete _file_names;
328 }
329 }
330
331 bool RepositoryIterator::has_next() const {
332 return _file_names != NULL && _iterator < _file_names->length();
333 }
334
335 const char* RepositoryIterator::next() const {
336 return _iterator >= _file_names->length() ? NULL : fully_qualified(_file_names->at(_iterator++));
337 }
338
339 static void write_repository_files(const RepositoryIterator& iterator, char* const copy_block, size_t block_size) {
340 assert(is_emergency_dump_file_open(), "invariant");
341 while (iterator.has_next()) {
342 fio_fd current_fd = invalid_fd;
343 const char* const fqn = iterator.next();
344 assert(fqn != NULL, "invariant");
345 current_fd = open_exclusivly(fqn);
346 if (current_fd != invalid_fd) {
347 const int64_t size = file_size(current_fd);
348 assert(size > 0, "invariant");
349 int64_t bytes_read = 0;
350 int64_t bytes_written = 0;
351 while (bytes_read < size) {
352 const ssize_t read_result = os::read_at(current_fd, copy_block, (int)block_size, bytes_read);
353 if (-1 == read_result) {
354 log_info(jfr)( // For user, should not be "jfr, system"
355 "Unable to recover JFR data");
356 break;
357 }
358 bytes_read += (int64_t)read_result;
359 assert(bytes_read - bytes_written <= (int64_t)block_size, "invariant");
360 bytes_written += (int64_t)os::write(emergency_fd, copy_block, bytes_read - bytes_written);
361 assert(bytes_read == bytes_written, "invariant");
362 }
363 os::close(current_fd);
364 }
365 }
366 }
367
368 static void write_emergency_dump_file(const RepositoryIterator& iterator) {
369 static const size_t block_size = 1 * M; // 1 mb
370 char* const copy_block = (char*)os::malloc(block_size, mtTracing);
371 if (copy_block == NULL) {
372 log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
373 log_error(jfr, system)("Unable to write jfr emergency dump file");
374 }
375 write_repository_files(iterator, copy_block, block_size);
376 os::free(copy_block);
377 }
378
379 void JfrEmergencyDump::on_vm_error(const char* repository_path) {
380 assert(repository_path != NULL, "invariant");
381 if (open_emergency_dump_file()) {
382 RepositoryIterator iterator(repository_path);
383 write_emergency_dump_file(iterator);
384 close_emergency_dump_file();
385 }
386 }
387
388 static const char* create_emergency_chunk_path(const char* repository_path) {
389 const size_t repository_path_len = strlen(repository_path);
390 char date_time_buffer[32] = { 0 };
391 date_time(date_time_buffer, sizeof(date_time_buffer));
392 // append the individual substrings
393 const int result = jio_snprintf(_path_buffer,
394 _max_path_buffer_size,
395 "%s%s%s%s",
396 repository_path,
397 os::file_separator(),
398 date_time_buffer,
399 chunk_file_jfr_ext);
400 return result == -1 ? NULL : _path_buffer;
401 }
402
403 const char* JfrEmergencyDump::chunk_path(const char* repository_path) {
404 if (repository_path == NULL) {
405 if (!open_emergency_dump_file()) {
406 return NULL;
407 }
408 // We can directly use the emergency dump file name as the chunk.
409 // The chunk writer will open its own fd so we close this descriptor.
410 close_emergency_dump_file();
411 assert(!is_path_empty(), "invariant");
412 return _path_buffer;
413 }
414 return create_emergency_chunk_path(repository_path);
415 }
416
417 /*
418 * We are just about to exit the VM, so we will be very aggressive
419 * at this point in order to increase overall success of dumping jfr data.
420 *
421 * If we end up deadlocking in the attempt of dumping out jfr data,
422 * we rely on the WatcherThread task "is_error_reported()",
423 * to exit the VM after a hard-coded timeout (disallow WatcherThread to emergency dump).
424 * This "safety net" somewhat explains the aggressiveness in this attempt.
425 *
426 */
427 static bool prepare_for_emergency_dump(Thread* thread) {
428 assert(thread != NULL, "invariant");
429
430 if (thread->is_Watcher_thread()) {
431 // need WatcherThread as a safeguard against potential deadlocks
432 return false;
433 }
434 if (JfrStream_lock->owned_by_self()) {
435 // crashed during jfr rotation, disallow recursion
436 return false;
437 }
438
439 #ifdef ASSERT
440 Mutex* owned_lock = thread->owned_locks();
441 while (owned_lock != NULL) {
442 Mutex* next = owned_lock->next();
443 owned_lock->unlock();
444 owned_lock = next;
445 }
446 #endif // ASSERT
447
448 if (Threads_lock->owned_by_self()) {
449 Threads_lock->unlock();
450 }
451
452 if (Module_lock->owned_by_self()) {
453 Module_lock->unlock();
454 }
455
456 if (ClassLoaderDataGraph_lock->owned_by_self()) {
457 ClassLoaderDataGraph_lock->unlock();
458 }
459
460 if (Heap_lock->owned_by_self()) {
461 Heap_lock->unlock();
462 }
463
464 if (VMOperationQueue_lock->owned_by_self()) {
465 VMOperationQueue_lock->unlock();
466 }
467
468 if (VMOperationRequest_lock->owned_by_self()) {
469 VMOperationRequest_lock->unlock();
470 }
471
472 if (Service_lock->owned_by_self()) {
473 Service_lock->unlock();
474 }
475
476 if (UseNotificationThread && Notification_lock->owned_by_self()) {
477 Notification_lock->unlock();
478 }
479
480 if (CodeCache_lock->owned_by_self()) {
481 CodeCache_lock->unlock();
482 }
483
484 if (PeriodicTask_lock->owned_by_self()) {
485 PeriodicTask_lock->unlock();
486 }
487
488 if (JfrMsg_lock->owned_by_self()) {
489 JfrMsg_lock->unlock();
490 }
491
492 if (JfrBuffer_lock->owned_by_self()) {
493 JfrBuffer_lock->unlock();
494 }
495
496 if (JfrStacktrace_lock->owned_by_self()) {
497 JfrStacktrace_lock->unlock();
498 }
499 return true;
500 }
501
502 static volatile int jfr_shutdown_lock = 0;
503
504 static bool guard_reentrancy() {
505 return Atomic::cmpxchg(&jfr_shutdown_lock, 0, 1) == 0;
506 }
507
508 class JavaThreadInVM : public StackObj {
509 private:
510 JavaThread* const _jt;
511 JavaThreadState _original_state;
512 public:
513
514 JavaThreadInVM(Thread* t) : _jt(t->is_Java_thread() ? (JavaThread*)t : NULL),
515 _original_state(_thread_max_state) {
516 if ((_jt != NULL) && (_jt->thread_state() != _thread_in_vm)) {
517 _original_state = _jt->thread_state();
518 _jt->set_thread_state(_thread_in_vm);
519 }
520 }
521
522 ~JavaThreadInVM() {
523 if (_original_state != _thread_max_state) {
524 _jt->set_thread_state(_original_state);
525 }
526 }
527
528 };
529
530 static void post_events(bool exception_handler) {
531 if (exception_handler) {
532 EventShutdown e;
533 e.set_reason("VM Error");
534 e.commit();
535 } else {
536 // OOM
537 LeakProfiler::emit_events(max_jlong, false);
538 }
539 EventDumpReason event;
540 event.set_reason(exception_handler ? "Crash" : "Out of Memory");
541 event.set_recordingId(-1);
542 event.commit();
543 }
544
545 void JfrEmergencyDump::on_vm_shutdown(bool exception_handler) {
546 if (!guard_reentrancy()) {
547 return;
548 }
549 Thread* thread = Thread::current_or_null_safe();
550 if (thread == NULL) {
551 return;
552 }
553 // Ensure a JavaThread is _thread_in_vm when we make this call
554 JavaThreadInVM jtivm(thread);
555 if (!prepare_for_emergency_dump(thread)) {
556 return;
557 }
558 post_events(exception_handler);
559 const int messages = MSGBIT(MSG_VM_ERROR);
560 JfrRecorderService service;
561 service.rotate(messages);
562 }