1 /*
   2  * Copyright (c) 2012, 2019, 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 "memory/resourceArea.hpp"
  35 #include "runtime/atomic.hpp"
  36 #include "runtime/handles.inline.hpp"
  37 #include "runtime/globals.hpp"
  38 #include "runtime/mutexLocker.hpp"
  39 #include "runtime/os.hpp"
  40 #include "runtime/thread.inline.hpp"
  41 #include "utilities/growableArray.hpp"
  42 
  43 static const char vm_error_filename_fmt[] = "hs_err_pid%p.jfr";
  44 static const char vm_oom_filename_fmt[] = "hs_oom_pid%p.jfr";
  45 static const char vm_soe_filename_fmt[] = "hs_soe_pid%p.jfr";
  46 static const char chunk_file_jfr_ext[] = ".jfr";
  47 static const size_t iso8601_len = 19; // "YYYY-MM-DDTHH:MM:SS"
  48 
  49 static fio_fd open_exclusivly(const char* path) {
  50   return os::open(path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE);
  51 }
  52 
  53 static int file_sort(const char** const file1, const char** file2) {
  54   assert(NULL != *file1 && NULL != *file2, "invariant");
  55   int cmp = strncmp(*file1, *file2, iso8601_len);
  56   if (0 == cmp) {
  57     const char* const dot1 = strchr(*file1, '.');
  58     assert(NULL != dot1, "invariant");
  59     const char* const dot2 = strchr(*file2, '.');
  60     assert(NULL != dot2, "invariant");
  61     ptrdiff_t file1_len = dot1 - *file1;
  62     ptrdiff_t file2_len = dot2 - *file2;
  63     if (file1_len < file2_len) {
  64       return -1;
  65     }
  66     if (file1_len > file2_len) {
  67       return 1;
  68     }
  69     assert(file1_len == file2_len, "invariant");
  70     cmp = strncmp(*file1, *file2, file1_len);
  71   }
  72   assert(cmp != 0, "invariant");
  73   return cmp;
  74 }
  75 
  76 static void iso8601_to_date_time(char* iso8601_str) {
  77   assert(iso8601_str != NULL, "invariant");
  78   assert(strlen(iso8601_str) == iso8601_len, "invariant");
  79   // "YYYY-MM-DDTHH:MM:SS"
  80   for (size_t i = 0; i < iso8601_len; ++i) {
  81     switch (iso8601_str[i]) {
  82     case 'T':
  83     case '-':
  84     case ':':
  85       iso8601_str[i] = '_';
  86       break;
  87     }
  88   }
  89   // "YYYY_MM_DD_HH_MM_SS"
  90 }
  91 
  92 static void date_time(char* buffer, size_t buffer_len) {
  93   assert(buffer != NULL, "invariant");
  94   assert(buffer_len >= iso8601_len, "buffer too small");
  95   os::iso8601_time(buffer, buffer_len);
  96   assert(strlen(buffer) >= iso8601_len + 1, "invariant");
  97   // "YYYY-MM-DDTHH:MM:SS"
  98   buffer[iso8601_len] = '\0';
  99   iso8601_to_date_time(buffer);
 100 }
 101 
 102 static int64_t file_size(fio_fd fd) {
 103   assert(fd != invalid_fd, "invariant");
 104   const int64_t current_offset = os::current_file_offset(fd);
 105   const int64_t size = os::lseek(fd, 0, SEEK_END);
 106   os::seek_to_file_offset(fd, current_offset);
 107   return size;
 108 }
 109 
 110 class RepositoryIterator : public StackObj {
 111  private:
 112   const char* const _repo;
 113   const size_t _repository_len;
 114   GrowableArray<const char*>* _files;
 115   const char* const fully_qualified(const char* entry) const;
 116   mutable int _iterator;
 117 
 118  public:
 119   RepositoryIterator(const char* repository, size_t repository_len);
 120   ~RepositoryIterator() {}
 121   const char* const filter(const char* entry) const;
 122   bool has_next() const;
 123   const char* const next() const;
 124 };
 125 
 126 const char* const RepositoryIterator::fully_qualified(const char* entry) const {
 127   assert(NULL != entry, "invariant");
 128   char* file_path_entry = NULL;
 129   // only use files that have content, not placeholders
 130   const char* const file_separator = os::file_separator();
 131   if (NULL != file_separator) {
 132     const size_t entry_len = strlen(entry);
 133     const size_t file_separator_length = strlen(file_separator);
 134     const size_t file_path_entry_length = _repository_len + file_separator_length + entry_len;
 135     file_path_entry = NEW_RESOURCE_ARRAY_RETURN_NULL(char, file_path_entry_length + 1);
 136     if (NULL == file_path_entry) {
 137       return NULL;
 138     }
 139     int position = 0;
 140     position += jio_snprintf(&file_path_entry[position], _repository_len + 1, "%s", _repo);
 141     position += jio_snprintf(&file_path_entry[position], file_separator_length + 1, "%s", os::file_separator());
 142     position += jio_snprintf(&file_path_entry[position], entry_len + 1, "%s", entry);
 143     file_path_entry[position] = '\0';
 144     assert((size_t)position == file_path_entry_length, "invariant");
 145     assert(strlen(file_path_entry) == (size_t)position, "invariant");
 146   }
 147   return file_path_entry;
 148 }
 149 
 150 const char* const RepositoryIterator::filter(const char* entry) const {
 151   if (entry == NULL) {
 152     return NULL;
 153   }
 154   const size_t entry_len = strlen(entry);
 155   if (entry_len <= 2) {
 156     // for "." and ".."
 157     return NULL;
 158   }
 159   char* entry_name = NEW_RESOURCE_ARRAY_RETURN_NULL(char, entry_len + 1);
 160   if (entry_name == NULL) {
 161     return NULL;
 162   }
 163   strncpy(entry_name, entry, entry_len + 1);
 164   const char* const fully_qualified_path_entry = fully_qualified(entry_name);
 165   if (NULL == fully_qualified_path_entry) {
 166     return NULL;
 167   }
 168   const fio_fd entry_fd = open_exclusivly(fully_qualified_path_entry);
 169   if (invalid_fd == entry_fd) {
 170     return NULL;
 171   }
 172   const int64_t entry_size = file_size(entry_fd);
 173   os::close(entry_fd);
 174   if (0 == entry_size) {
 175     return NULL;
 176   }
 177   return entry_name;
 178 }
 179 
 180 RepositoryIterator::RepositoryIterator(const char* repository, size_t repository_len) :
 181   _repo(repository),
 182   _repository_len(repository_len),
 183   _files(NULL),
 184   _iterator(0) {
 185   if (NULL != _repo) {
 186     assert(strlen(_repo) == _repository_len, "invariant");
 187     _files = new GrowableArray<const char*>(10);
 188     DIR* dirp = os::opendir(_repo);
 189     if (dirp == NULL) {
 190       log_error(jfr, system)("Unable to open repository %s", _repo);
 191       return;
 192     }
 193     struct dirent* dentry;
 194     while ((dentry = os::readdir(dirp)) != NULL) {
 195       const char* const entry_path = filter(dentry->d_name);
 196       if (NULL != entry_path) {
 197         _files->append(entry_path);
 198       }
 199     }
 200     os::closedir(dirp);
 201     if (_files->length() > 1) {
 202       _files->sort(file_sort);
 203     }
 204   }
 205 }
 206 
 207 bool RepositoryIterator::has_next() const {
 208   return (_files != NULL && _iterator < _files->length());
 209 }
 210 
 211 const char* const RepositoryIterator::next() const {
 212   return _iterator >= _files->length() ? NULL : fully_qualified(_files->at(_iterator++));
 213 }
 214 
 215 static void write_emergency_file(fio_fd emergency_fd, const RepositoryIterator& iterator) {
 216   assert(emergency_fd != invalid_fd, "invariant");
 217   const size_t size_of_file_copy_block = 1 * M; // 1 mb
 218   jbyte* const file_copy_block = NEW_RESOURCE_ARRAY_RETURN_NULL(jbyte, size_of_file_copy_block);
 219   if (file_copy_block == NULL) {
 220     return;
 221   }
 222   while (iterator.has_next()) {
 223     fio_fd current_fd = invalid_fd;
 224     const char* const fqn = iterator.next();
 225     if (fqn != NULL) {
 226       current_fd = open_exclusivly(fqn);
 227       if (current_fd != invalid_fd) {
 228         const int64_t current_filesize = file_size(current_fd);
 229         assert(current_filesize > 0, "invariant");
 230         int64_t bytes_read = 0;
 231         int64_t bytes_written = 0;
 232         while (bytes_read < current_filesize) {
 233           const ssize_t read_result = os::read_at(current_fd, file_copy_block, size_of_file_copy_block, bytes_read);
 234           if (-1 == read_result) {
 235             log_info(jfr)( // For user, should not be "jfr, system"
 236               "Unable to recover JFR data");
 237             break;
 238           }
 239           bytes_read += (int64_t)read_result;
 240           assert(bytes_read - bytes_written <= (int64_t)size_of_file_copy_block, "invariant");
 241           bytes_written += (int64_t)os::write(emergency_fd, file_copy_block, bytes_read - bytes_written);
 242           assert(bytes_read == bytes_written, "invariant");
 243         }
 244         os::close(current_fd);
 245       }
 246     }
 247   }
 248 }
 249 
 250 static const char* create_emergency_dump_path() {
 251   assert(JfrStream_lock->owned_by_self(), "invariant");
 252   char* buffer = NEW_RESOURCE_ARRAY_RETURN_NULL(char, JVM_MAXPATHLEN);
 253   if (NULL == buffer) {
 254     return NULL;
 255   }
 256   const char* const cwd = os::get_current_directory(buffer, JVM_MAXPATHLEN);
 257   if (NULL == cwd) {
 258     return NULL;
 259   }
 260   size_t pos = strlen(cwd);
 261   const int fsep_len = jio_snprintf(&buffer[pos], JVM_MAXPATHLEN - pos, "%s", os::file_separator());
 262   const char* filename_fmt = NULL;
 263   // fetch specific error cause
 264   switch (JfrJavaSupport::cause()) {
 265     case JfrJavaSupport::OUT_OF_MEMORY:
 266       filename_fmt = vm_oom_filename_fmt;
 267       break;
 268     case JfrJavaSupport::STACK_OVERFLOW:
 269       filename_fmt = vm_soe_filename_fmt;
 270       break;
 271     default:
 272       filename_fmt = vm_error_filename_fmt;
 273   }
 274   char* emergency_dump_path = NULL;
 275   pos += fsep_len;
 276   if (Arguments::copy_expand_pid(filename_fmt, strlen(filename_fmt), &buffer[pos], JVM_MAXPATHLEN - pos)) {
 277     const size_t emergency_filename_length = strlen(buffer);
 278     emergency_dump_path = NEW_RESOURCE_ARRAY_RETURN_NULL(char, emergency_filename_length + 1);
 279     if (NULL == emergency_dump_path) {
 280       return NULL;
 281     }
 282     strncpy(emergency_dump_path, buffer, emergency_filename_length + 1);
 283   }
 284   if (emergency_dump_path != NULL) {
 285     log_info(jfr)( // For user, should not be "jfr, system"
 286       "Attempting to recover JFR data, emergency jfr file: %s", emergency_dump_path);
 287   }
 288   return emergency_dump_path;
 289 }
 290 
 291 // Caller needs ResourceMark
 292 static const char* create_emergency_chunk_path(const char* repository_path) {
 293   assert(repository_path != NULL, "invariant");
 294   assert(JfrStream_lock->owned_by_self(), "invariant");
 295   const size_t repository_path_len = strlen(repository_path);
 296   // date time
 297   char date_time_buffer[32] = { 0 };
 298   date_time(date_time_buffer, sizeof(date_time_buffer));
 299   size_t date_time_len = strlen(date_time_buffer);
 300   size_t chunkname_max_len = repository_path_len          // repository_base_path
 301                              + 1                          // "/"
 302                              + date_time_len              // date_time
 303                              + strlen(chunk_file_jfr_ext) // .jfr
 304                              + 1;
 305   char* chunk_path = NEW_RESOURCE_ARRAY_RETURN_NULL(char, chunkname_max_len);
 306   if (chunk_path == NULL) {
 307     return NULL;
 308   }
 309   // append the individual substrings
 310   jio_snprintf(chunk_path, chunkname_max_len, "%s%s%s%s", repository_path_len, os::file_separator(), date_time_buffer, chunk_file_jfr_ext);
 311   return chunk_path;
 312 }
 313 
 314 static fio_fd emergency_dump_file_descriptor() {
 315   assert(JfrStream_lock->owned_by_self(), "invariant");
 316   ResourceMark rm;
 317   const char* const emergency_dump_path = create_emergency_dump_path();
 318   return emergency_dump_path != NULL ? open_exclusivly(emergency_dump_path) : invalid_fd;
 319 }
 320 
 321 const char* JfrEmergencyDump::build_dump_path(const char* repository_path) {
 322   return repository_path == NULL ? create_emergency_dump_path() : create_emergency_chunk_path(repository_path);
 323 }
 324 
 325 void JfrEmergencyDump::on_vm_error(const char* repository_path) {
 326   assert(repository_path != NULL, "invariant");
 327   ResourceMark rm;
 328   MutexLocker stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
 329   const fio_fd emergency_fd = emergency_dump_file_descriptor();
 330   if (emergency_fd != invalid_fd) {
 331     RepositoryIterator iterator(repository_path, strlen(repository_path));
 332     write_emergency_file(emergency_fd, iterator);
 333     os::close(emergency_fd);
 334   }
 335 }
 336 
 337 /*
 338 * We are just about to exit the VM, so we will be very aggressive
 339 * at this point in order to increase overall success of dumping jfr data:
 340 *
 341 * 1. if the thread state is not "_thread_in_vm", we will quick transition
 342 *    it to "_thread_in_vm".
 343 * 2. the nesting state for both resource and handle areas are unknown,
 344 *    so we allocate new fresh arenas, discarding the old ones.
 345 * 3. if the thread is the owner of some critical lock(s), unlock them.
 346 *
 347 * If we end up deadlocking in the attempt of dumping out jfr data,
 348 * we rely on the WatcherThread task "is_error_reported()",
 349 * to exit the VM after a hard-coded timeout.
 350 * This "safety net" somewhat explains the aggressiveness in this attempt.
 351 *
 352 */
 353 static void prepare_for_emergency_dump(Thread* thread) {
 354   if (thread->is_Java_thread()) {
 355     ((JavaThread*)thread)->set_thread_state(_thread_in_vm);
 356   }
 357 
 358 #ifdef ASSERT
 359   Monitor* owned_lock = thread->owned_locks();
 360   while (owned_lock != NULL) {
 361     Monitor* next = owned_lock->next();
 362     owned_lock->unlock();
 363     owned_lock = next;
 364   }
 365 #endif // ASSERT
 366 
 367   if (Threads_lock->owned_by_self()) {
 368     Threads_lock->unlock();
 369   }
 370 
 371   if (Module_lock->owned_by_self()) {
 372     Module_lock->unlock();
 373   }
 374 
 375   if (ClassLoaderDataGraph_lock->owned_by_self()) {
 376     ClassLoaderDataGraph_lock->unlock();
 377   }
 378 
 379   if (Heap_lock->owned_by_self()) {
 380     Heap_lock->unlock();
 381   }
 382 
 383   if (VMOperationQueue_lock->owned_by_self()) {
 384     VMOperationQueue_lock->unlock();
 385   }
 386 
 387   if (VMOperationRequest_lock->owned_by_self()) {
 388     VMOperationRequest_lock->unlock();
 389   }
 390 
 391 
 392   if (Service_lock->owned_by_self()) {
 393     Service_lock->unlock();
 394   }
 395 
 396   if (CodeCache_lock->owned_by_self()) {
 397     CodeCache_lock->unlock();
 398   }
 399 
 400   if (PeriodicTask_lock->owned_by_self()) {
 401     PeriodicTask_lock->unlock();
 402   }
 403 
 404   if (JfrMsg_lock->owned_by_self()) {
 405     JfrMsg_lock->unlock();
 406   }
 407 
 408   if (JfrBuffer_lock->owned_by_self()) {
 409     JfrBuffer_lock->unlock();
 410   }
 411 
 412   if (JfrStream_lock->owned_by_self()) {
 413     JfrStream_lock->unlock();
 414   }
 415 
 416   if (JfrStacktrace_lock->owned_by_self()) {
 417     JfrStacktrace_lock->unlock();
 418   }
 419 }
 420 
 421 static volatile int jfr_shutdown_lock = 0;
 422 
 423 static bool guard_reentrancy() {
 424   return Atomic::cmpxchg(1, &jfr_shutdown_lock, 0) == 0;
 425 }
 426 
 427 void JfrEmergencyDump::on_vm_shutdown(bool exception_handler) {
 428   if (!guard_reentrancy()) {
 429     return;
 430   }
 431   // function made non-reentrant
 432   Thread* thread = Thread::current();
 433   if (exception_handler) {
 434     // we are crashing
 435     if (thread->is_Watcher_thread()) {
 436       // The Watcher thread runs the periodic thread sampling task.
 437       // If it has crashed, it is likely that another thread is
 438       // left in a suspended state. This would mean the system
 439       // will not be able to ever move to a safepoint. We try
 440       // to avoid issuing safepoint operations when attempting
 441       // an emergency dump, but a safepoint might be already pending.
 442       return;
 443     }
 444     prepare_for_emergency_dump(thread);
 445   }
 446   EventDumpReason event;
 447   if (event.should_commit()) {
 448     event.set_reason(exception_handler ? "Crash" : "Out of Memory");
 449     event.set_recordingId(-1);
 450     event.commit();
 451   }
 452   if (!exception_handler) {
 453     // OOM
 454     LeakProfiler::emit_events(max_jlong, false);
 455   }
 456   const int messages = MSGBIT(MSG_VM_ERROR);
 457   ResourceMark rm(thread);
 458   HandleMark hm(thread);
 459   JfrRecorderService service;
 460   service.rotate(messages);
 461 }
--- EOF ---