diff -r 1f9ad92e337b -r 3cabb47758c9 src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp
--- a/src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp	Mon Mar 25 14:11:09 2019 +0100
+++ b/src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp	Mon Mar 25 15:37:06 2019 +0100
@@ -24,17 +24,315 @@
 
 #include "precompiled.hpp"
 #include "jfr/jfrEvents.hpp"
+#include "jfr/jni/jfrJavaSupport.hpp"
 #include "jfr/leakprofiler/leakProfiler.hpp"
 #include "jfr/recorder/repository/jfrEmergencyDump.hpp"
 #include "jfr/recorder/service/jfrPostBox.hpp"
 #include "jfr/recorder/service/jfrRecorderService.hpp"
 #include "jfr/utilities/jfrTypes.hpp"
+#include "logging/log.hpp"
 #include "memory/resourceArea.hpp"
 #include "runtime/atomic.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/globals.hpp"
 #include "runtime/mutexLocker.hpp"
-#include "runtime/thread.hpp"
+#include "runtime/os.hpp"
+#include "runtime/thread.inline.hpp"
+#include "utilities/growableArray.hpp"
+
+static const char vm_error_filename_fmt[] = "hs_err_pid%p.jfr";
+static const char vm_oom_filename_fmt[] = "hs_oom_pid%p.jfr";
+static const char vm_soe_filename_fmt[] = "hs_soe_pid%p.jfr";
+static const char chunk_file_jfr_ext[] = ".jfr";
+static const size_t iso8601_len = 19; // "YYYY-MM-DDTHH:MM:SS"
+
+static fio_fd open_exclusivly(const char* path) {
+  return os::open(path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE);
+}
+
+static int file_sort(const char** const file1, const char** file2) {
+  assert(NULL != *file1 && NULL != *file2, "invariant");
+  int cmp = strncmp(*file1, *file2, iso8601_len);
+  if (0 == cmp) {
+    const char* const dot1 = strchr(*file1, '.');
+    assert(NULL != dot1, "invariant");
+    const char* const dot2 = strchr(*file2, '.');
+    assert(NULL != dot2, "invariant");
+    ptrdiff_t file1_len = dot1 - *file1;
+    ptrdiff_t file2_len = dot2 - *file2;
+    if (file1_len < file2_len) {
+      return -1;
+    }
+    if (file1_len > file2_len) {
+      return 1;
+    }
+    assert(file1_len == file2_len, "invariant");
+    cmp = strncmp(*file1, *file2, file1_len);
+  }
+  assert(cmp != 0, "invariant");
+  return cmp;
+}
+
+static void iso8601_to_date_time(char* iso8601_str) {
+  assert(iso8601_str != NULL, "invariant");
+  assert(strlen(iso8601_str) == iso8601_len, "invariant");
+  // "YYYY-MM-DDTHH:MM:SS"
+  for (size_t i = 0; i < iso8601_len; ++i) {
+    switch (iso8601_str[i]) {
+    case 'T':
+    case '-':
+    case ':':
+      iso8601_str[i] = '_';
+      break;
+    }
+  }
+  // "YYYY_MM_DD_HH_MM_SS"
+}
+
+static void date_time(char* buffer, size_t buffer_len) {
+  assert(buffer != NULL, "invariant");
+  assert(buffer_len >= iso8601_len, "buffer too small");
+  os::iso8601_time(buffer, buffer_len);
+  assert(strlen(buffer) >= iso8601_len + 1, "invariant");
+  // "YYYY-MM-DDTHH:MM:SS"
+  buffer[iso8601_len] = '\0';
+  iso8601_to_date_time(buffer);
+}
+
+static int64_t file_size(fio_fd fd) {
+  assert(fd != invalid_fd, "invariant");
+  const int64_t current_offset = os::current_file_offset(fd);
+  const int64_t size = os::lseek(fd, 0, SEEK_END);
+  os::seek_to_file_offset(fd, current_offset);
+  return size;
+}
+
+class RepositoryIterator : public StackObj {
+ private:
+  const char* const _repo;
+  const size_t _repository_len;
+  GrowableArray<const char*>* _files;
+  const char* const fully_qualified(const char* entry) const;
+  mutable int _iterator;
+
+ public:
+  RepositoryIterator(const char* repository, size_t repository_len);
+  ~RepositoryIterator() {}
+  const char* const filter(const char* entry) const;
+  bool has_next() const;
+  const char* const next() const;
+};
+
+const char* const RepositoryIterator::fully_qualified(const char* entry) const {
+  assert(NULL != entry, "invariant");
+  char* file_path_entry = NULL;
+  // only use files that have content, not placeholders
+  const char* const file_separator = os::file_separator();
+  if (NULL != file_separator) {
+    const size_t entry_len = strlen(entry);
+    const size_t file_separator_length = strlen(file_separator);
+    const size_t file_path_entry_length = _repository_len + file_separator_length + entry_len;
+    file_path_entry = NEW_RESOURCE_ARRAY_RETURN_NULL(char, file_path_entry_length + 1);
+    if (NULL == file_path_entry) {
+      return NULL;
+    }
+    int position = 0;
+    position += jio_snprintf(&file_path_entry[position], _repository_len + 1, "%s", _repo);
+    position += jio_snprintf(&file_path_entry[position], file_separator_length + 1, "%s", os::file_separator());
+    position += jio_snprintf(&file_path_entry[position], entry_len + 1, "%s", entry);
+    file_path_entry[position] = '\0';
+    assert((size_t)position == file_path_entry_length, "invariant");
+    assert(strlen(file_path_entry) == (size_t)position, "invariant");
+  }
+  return file_path_entry;
+}
+
+const char* const RepositoryIterator::filter(const char* entry) const {
+  if (entry == NULL) {
+    return NULL;
+  }
+  const size_t entry_len = strlen(entry);
+  if (entry_len <= 2) {
+    // for "." and ".."
+    return NULL;
+  }
+  char* entry_name = NEW_RESOURCE_ARRAY_RETURN_NULL(char, entry_len + 1);
+  if (entry_name == NULL) {
+    return NULL;
+  }
+  strncpy(entry_name, entry, entry_len + 1);
+  const char* const fully_qualified_path_entry = fully_qualified(entry_name);
+  if (NULL == fully_qualified_path_entry) {
+    return NULL;
+  }
+  const fio_fd entry_fd = open_exclusivly(fully_qualified_path_entry);
+  if (invalid_fd == entry_fd) {
+    return NULL;
+  }
+  const int64_t entry_size = file_size(entry_fd);
+  os::close(entry_fd);
+  if (0 == entry_size) {
+    return NULL;
+  }
+  return entry_name;
+}
+
+RepositoryIterator::RepositoryIterator(const char* repository, size_t repository_len) :
+  _repo(repository),
+  _repository_len(repository_len),
+  _files(NULL),
+  _iterator(0) {
+  if (NULL != _repo) {
+    assert(strlen(_repo) == _repository_len, "invariant");
+    _files = new GrowableArray<const char*>(10);
+    DIR* dirp = os::opendir(_repo);
+    if (dirp == NULL) {
+      log_error(jfr, system)("Unable to open repository %s", _repo);
+      return;
+    }
+    struct dirent* dentry;
+    while ((dentry = os::readdir(dirp)) != NULL) {
+      const char* const entry_path = filter(dentry->d_name);
+      if (NULL != entry_path) {
+        _files->append(entry_path);
+      }
+    }
+    os::closedir(dirp);
+    if (_files->length() > 1) {
+      _files->sort(file_sort);
+    }
+  }
+}
+
+bool RepositoryIterator::has_next() const {
+  return (_files != NULL && _iterator < _files->length());
+}
+
+const char* const RepositoryIterator::next() const {
+  return _iterator >= _files->length() ? NULL : fully_qualified(_files->at(_iterator++));
+}
+
+static void write_emergency_file(fio_fd emergency_fd, const RepositoryIterator& iterator) {
+  assert(emergency_fd != invalid_fd, "invariant");
+  const size_t size_of_file_copy_block = 1 * M; // 1 mb
+  jbyte* const file_copy_block = NEW_RESOURCE_ARRAY_RETURN_NULL(jbyte, size_of_file_copy_block);
+  if (file_copy_block == NULL) {
+    return;
+  }
+  while (iterator.has_next()) {
+    fio_fd current_fd = invalid_fd;
+    const char* const fqn = iterator.next();
+    if (fqn != NULL) {
+      current_fd = open_exclusivly(fqn);
+      if (current_fd != invalid_fd) {
+        const int64_t current_filesize = file_size(current_fd);
+        assert(current_filesize > 0, "invariant");
+        int64_t bytes_read = 0;
+        int64_t bytes_written = 0;
+        while (bytes_read < current_filesize) {
+          const ssize_t read_result = os::read_at(current_fd, file_copy_block, size_of_file_copy_block, bytes_read);
+          if (-1 == read_result) {
+            log_info(jfr)( // For user, should not be "jfr, system"
+              "Unable to recover JFR data");
+            break;
+          }
+          bytes_read += (int64_t)read_result;
+          assert(bytes_read - bytes_written <= (int64_t)size_of_file_copy_block, "invariant");
+          bytes_written += (int64_t)os::write(emergency_fd, file_copy_block, bytes_read - bytes_written);
+          assert(bytes_read == bytes_written, "invariant");
+        }
+        os::close(current_fd);
+      }
+    }
+  }
+}
+
+static const char* create_emergency_dump_path() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  char* buffer = NEW_RESOURCE_ARRAY_RETURN_NULL(char, JVM_MAXPATHLEN);
+  if (NULL == buffer) {
+    return NULL;
+  }
+  const char* const cwd = os::get_current_directory(buffer, JVM_MAXPATHLEN);
+  if (NULL == cwd) {
+    return NULL;
+  }
+  size_t pos = strlen(cwd);
+  const int fsep_len = jio_snprintf(&buffer[pos], JVM_MAXPATHLEN - pos, "%s", os::file_separator());
+  const char* filename_fmt = NULL;
+  // fetch specific error cause
+  switch (JfrJavaSupport::cause()) {
+    case JfrJavaSupport::OUT_OF_MEMORY:
+      filename_fmt = vm_oom_filename_fmt;
+      break;
+    case JfrJavaSupport::STACK_OVERFLOW:
+      filename_fmt = vm_soe_filename_fmt;
+      break;
+    default:
+      filename_fmt = vm_error_filename_fmt;
+  }
+  char* emergency_dump_path = NULL;
+  pos += fsep_len;
+  if (Arguments::copy_expand_pid(filename_fmt, strlen(filename_fmt), &buffer[pos], JVM_MAXPATHLEN - pos)) {
+    const size_t emergency_filename_length = strlen(buffer);
+    emergency_dump_path = NEW_RESOURCE_ARRAY_RETURN_NULL(char, emergency_filename_length + 1);
+    if (NULL == emergency_dump_path) {
+      return NULL;
+    }
+    strncpy(emergency_dump_path, buffer, emergency_filename_length + 1);
+  }
+  if (emergency_dump_path != NULL) {
+    log_info(jfr)( // For user, should not be "jfr, system"
+      "Attempting to recover JFR data, emergency jfr file: %s", emergency_dump_path);
+  }
+  return emergency_dump_path;
+}
+
+// Caller needs ResourceMark
+static const char* create_emergency_chunk_path(const char* repository_path) {
+  assert(repository_path != NULL, "invariant");
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  const size_t repository_path_len = strlen(repository_path);
+  // date time
+  char date_time_buffer[32] = { 0 };
+  date_time(date_time_buffer, sizeof(date_time_buffer));
+  size_t date_time_len = strlen(date_time_buffer);
+  size_t chunkname_max_len = repository_path_len          // repository_base_path
+                             + 1                          // "/"
+                             + date_time_len              // date_time
+                             + strlen(chunk_file_jfr_ext) // .jfr
+                             + 1;
+  char* chunk_path = NEW_RESOURCE_ARRAY_RETURN_NULL(char, chunkname_max_len);
+  if (chunk_path == NULL) {
+    return NULL;
+  }
+  // append the individual substrings
+  jio_snprintf(chunk_path, chunkname_max_len, "%s%s%s%s", repository_path_len, os::file_separator(), date_time_buffer, chunk_file_jfr_ext);
+  return chunk_path;
+}
+
+static fio_fd emergency_dump_file_descriptor() {
+  assert(JfrStream_lock->owned_by_self(), "invariant");
+  ResourceMark rm;
+  const char* const emergency_dump_path = create_emergency_dump_path();
+  return emergency_dump_path != NULL ? open_exclusivly(emergency_dump_path) : invalid_fd;
+}
+
+const char* JfrEmergencyDump::build_dump_path(const char* repository_path) {
+  return repository_path == NULL ? create_emergency_dump_path() : create_emergency_chunk_path(repository_path);
+}
+
+void JfrEmergencyDump::on_vm_error(const char* repository_path) {
+  assert(repository_path != NULL, "invariant");
+  ResourceMark rm;
+  MutexLockerEx stream_lock(JfrStream_lock, Mutex::_no_safepoint_check_flag);
+  const fio_fd emergency_fd = emergency_dump_file_descriptor();
+  if (emergency_fd != invalid_fd) {
+    RepositoryIterator iterator(repository_path, strlen(repository_path));
+    write_emergency_file(emergency_fd, iterator);
+    os::close(emergency_fd);
+  }
+}
 
 /*
 * We are just about to exit the VM, so we will be very aggressive