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src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -29,29 +29,148 @@
#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/os.hpp"
#include "runtime/thread.inline.hpp"
#include "utilities/growableArray.hpp"
+#include "utilities/ostream.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 emergency_fd = invalid_fd;
+static const int64_t chunk_file_header_size = 68;
+static const size_t chunk_file_extension_length = sizeof chunk_file_jfr_ext - 1;
+
+/*
+ * The emergency dump logic is restrictive when it comes to
+ * using internal VM constructs such as ResourceArea / Handle / Arena.
+ * The reason being that the thread context is unknown.
+ *
+ * A single static buffer of size JVM_MAXPATHLEN is used for building paths.
+ * os::malloc / os::free are used in a few places.
+ */
+
+static const size_t _max_path_buffer_size = JVM_MAXPATHLEN;
+static char _path_buffer[_max_path_buffer_size] = { 0 };
+
+static bool is_empty(const char* path) {
+ assert(path != NULL, "invariant");
+ return path[0] == '\0';
+}
+
+static bool is_path_empty() {
+ return is_empty(_path_buffer);
+}
+
+static size_t append(char* path, int path_len, size_t pos, const char* str) {
+ assert(path_len - pos > 0, "invariant");
+ const int result = jio_snprintf(path + pos, path_len - pos, "%s", str);
+ return result == -1 ? 0 : pos + (size_t)result;
+}
+
+// returns with an appended file separator (if successful)
+static size_t get_current_directory(char* path, int path_len) {
+ assert(path != NULL, "invariant");
+ if (os::get_current_directory(path, path_len) == NULL) {
+ return 0;
+ }
+ return append(path, path_len, strlen(path), os::file_separator());
+}
static fio_fd open_exclusivly(const char* path) {
+ assert(path != NULL, "invariant");
+ assert(!is_empty(path), "invariant");
return os::open(path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE);
}
+static bool is_emergency_dump_file_open() {
+ return emergency_fd != invalid_fd;
+}
+
+static bool open_emergency_dump_fd(const char* path) {
+ if (path == NULL) {
+ return false;
+ }
+ assert(emergency_fd == invalid_fd, "invariant");
+ emergency_fd = open_exclusivly(path);
+ return emergency_fd != invalid_fd;
+}
+
+static void close_emergency_dump_file() {
+ if (is_emergency_dump_file_open()) {
+ os::close(emergency_fd);
+ }
+}
+
+static const char* create_emergency_dump_path() {
+ assert(is_path_empty(), "invariant");
+
+ char* const path = _path_buffer;
+ const size_t path_len = get_current_directory(path, _max_path_buffer_size);
+ if (path_len == 0) {
+ return NULL;
+ }
+ 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;
+ }
+ const bool result = Arguments::copy_expand_pid(filename_fmt, strlen(filename_fmt), path + path_len, _max_path_buffer_size - path_len);
+ return result ? path : NULL;
+}
+
+static bool open_emergency_dump_file() {
+ if (is_emergency_dump_file_open()) {
+ // opened already
+ return true;
+ }
+ return open_emergency_dump_fd(create_emergency_dump_path());
+}
+
+static void report(outputStream* st, bool emergency_file_opened, const char* repository_path) {
+ assert(st != NULL, "invariant");
+ if (emergency_file_opened) {
+ st->print_raw("# JFR recording file will be written. Location: ");
+ st->print_raw_cr(_path_buffer);
+ st->print_raw_cr("#");
+ } else if (repository_path != NULL) {
+ st->print_raw("# The JFR repository may contain useful JFR files. Location: ");
+ st->print_raw_cr(repository_path);
+ st->print_raw_cr("#");
+ } else if (!is_path_empty()) {
+ st->print_raw("# Unable to create a JFR recording file at location: ");
+ st->print_raw_cr(_path_buffer);
+ st->print_raw_cr("#");
+ }
+}
+
+void JfrEmergencyDump::on_vm_error_report(outputStream* st, const char* repository_path) {
+ assert(st != NULL, "invariant");
+ Thread* thread = Thread::current_or_null_safe();
+ if (thread != NULL) {
+ report(st, open_emergency_dump_file(), repository_path);
+ } else if (repository_path != NULL) {
+ // a non-attached thread will not be able to write anything later
+ report(st, false, repository_path);
+ }
+}
+
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, '.');
@@ -107,229 +226,199 @@
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;
+ GrowableArray<const char*>* _file_names;
+ size_t _path_buffer_file_name_offset;
mutable int _iterator;
-
+ const char* fully_qualified(const char* file_name) const;
+ const char* filter(const char* file_name) const;
public:
- RepositoryIterator(const char* repository, size_t repository_len);
- ~RepositoryIterator() {}
- const char* const filter(const char* entry) const;
+ RepositoryIterator(const char* repository_path);
+ ~RepositoryIterator();
bool has_next() const;
- const char* const next() const;
+ const char* 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;
+// append the file_name at the _path_buffer_file_name_offset position
+const char* RepositoryIterator::fully_qualified(const char* file_name) const {
+ assert(NULL != file_name, "invariant");
+ char* const path = _path_buffer;
+ assert(!is_empty(path), "invariant");
+ assert(_path_buffer_file_name_offset != 0, "invariant");
+ return append(path, _max_path_buffer_size, _path_buffer_file_name_offset, file_name) != 0 ? path : NULL;
}
-const char* const RepositoryIterator::filter(const char* entry) const {
- if (entry == NULL) {
+// caller responsible for deallocation
+const char* RepositoryIterator::filter(const char* file_name) const {
+ if (file_name == NULL) {
return NULL;
}
- const size_t entry_len = strlen(entry);
- if (entry_len <= 2) {
- // for "." and ".."
+ const size_t len = strlen(file_name);
+ if ((len < chunk_file_extension_length) ||
+ (strncmp(&file_name[len - chunk_file_extension_length],
+ chunk_file_jfr_ext,
+ chunk_file_extension_length) != 0)) {
+ // not a .jfr file
return NULL;
}
- char* entry_name = NEW_RESOURCE_ARRAY_RETURN_NULL(char, entry_len + 1);
- if (entry_name == NULL) {
+ const char* fqn = fully_qualified(file_name);
+ if (fqn == 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) {
+ const fio_fd fd = open_exclusivly(fqn);
+ if (invalid_fd == fd) {
return NULL;
}
- const fio_fd entry_fd = open_exclusivly(fully_qualified_path_entry);
- if (invalid_fd == entry_fd) {
+ const int64_t size = file_size(fd);
+ os::close(fd);
+ if (size <= chunk_file_header_size) {
return NULL;
}
- const int64_t entry_size = file_size(entry_fd);
- os::close(entry_fd);
- if (0 == entry_size) {
+ char* const file_name_copy = (char*)os::malloc(len + 1, mtTracing);
+ if (file_name_copy == NULL) {
+ log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
return NULL;
}
- return entry_name;
+ strncpy(file_name_copy, file_name, len + 1);
+ return file_name_copy;
}
-RepositoryIterator::RepositoryIterator(const char* repository, size_t repository_len) :
- _repo(repository),
- _repository_len(repository_len),
- _files(NULL),
+RepositoryIterator::RepositoryIterator(const char* repository_path) :
+ _file_names(NULL),
+ _path_buffer_file_name_offset(0),
_iterator(0) {
- if (NULL != _repo) {
- assert(strlen(_repo) == _repository_len, "invariant");
- _files = new GrowableArray<const char*>(10);
- DIR* dirp = os::opendir(_repo);
+ DIR* dirp = os::opendir(repository_path);
if (dirp == NULL) {
- log_error(jfr, system)("Unable to open repository %s", _repo);
+ log_error(jfr, system)("Unable to open repository %s", repository_path);
+ return;
+ }
+ char* const path = _path_buffer;
+ // store repository path in the path buffer
+ size_t result = append(path, _max_path_buffer_size, 0, repository_path);
+ if (result == 0) {
+ return;
+ }
+ // append a file separator and save that position
+ _path_buffer_file_name_offset = append(path, _max_path_buffer_size, result, os::file_separator());
+ if (_path_buffer_file_name_offset == 0) {
+ return;
+ }
+ _file_names = new (ResourceObj::C_HEAP, mtTracing) GrowableArray<const char*>(10, true, mtTracing);
+ if (_file_names == NULL) {
+ log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
return;
}
+ // iterate files in the repository and append filtered file names to the files array
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);
+ const char* file_name = filter(dentry->d_name);
+ if (file_name != NULL) {
+ _file_names->append(file_name);
}
}
os::closedir(dirp);
- if (_files->length() > 1) {
- _files->sort(file_sort);
+ if (_file_names->length() > 1) {
+ _file_names->sort(file_sort);
+ }
+}
+
+RepositoryIterator::~RepositoryIterator() {
+ if (_file_names != NULL) {
+ for (int i = 0; i < _file_names->length(); ++i) {
+ os::free(const_cast<char*>(_file_names->at(i)));
}
+ delete _file_names;
}
}
bool RepositoryIterator::has_next() const {
- return (_files != NULL && _iterator < _files->length());
+ return _file_names != NULL && _iterator < _file_names->length();
}
-const char* const RepositoryIterator::next() const {
- return _iterator >= _files->length() ? NULL : fully_qualified(_files->at(_iterator++));
+const char* RepositoryIterator::next() const {
+ return _iterator >= _file_names->length() ? NULL : fully_qualified(_file_names->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;
- }
+static void write_repository_files(const RepositoryIterator& iterator, char* const copy_block, size_t block_size) {
+ assert(is_emergency_dump_file_open(), "invariant");
while (iterator.has_next()) {
fio_fd current_fd = invalid_fd;
const char* const fqn = iterator.next();
- if (fqn != NULL) {
+ assert(fqn != NULL, "invariant");
current_fd = open_exclusivly(fqn);
if (current_fd != invalid_fd) {
- const int64_t current_filesize = file_size(current_fd);
- assert(current_filesize > 0, "invariant");
+ const int64_t size = file_size(current_fd);
+ assert(size > 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);
+ while (bytes_read < size) {
+ const ssize_t read_result = os::read_at(current_fd, copy_block, (int)block_size, 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 <= (int64_t)block_size, "invariant");
+ bytes_written += (int64_t)os::write(emergency_fd, copy_block, bytes_read - bytes_written);
assert(bytes_read == bytes_written, "invariant");
}
os::close(current_fd);
}
}
- }
}
-static const char* create_emergency_dump_path() {
- 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;
+static void write_emergency_dump_file(const RepositoryIterator& iterator) {
+ static const size_t block_size = 1 * M; // 1 mb
+ char* const copy_block = (char*)os::malloc(block_size, mtTracing);
+ if (copy_block == NULL) {
+ log_error(jfr, system)("Unable to malloc memory during jfr emergency dump");
+ log_error(jfr, system)("Unable to write jfr emergency dump file");
}
- 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);
+ write_repository_files(iterator, copy_block, block_size);
+ os::free(copy_block);
+}
+
+void JfrEmergencyDump::on_vm_error(const char* repository_path) {
+ assert(repository_path != NULL, "invariant");
+ if (open_emergency_dump_file()) {
+ RepositoryIterator iterator(repository_path);
+ write_emergency_dump_file(iterator);
+ close_emergency_dump_file();
}
- return emergency_dump_path;
}
-// Caller needs ResourceMark
static const char* create_emergency_chunk_path(const char* repository_path) {
- assert(repository_path != NULL, "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;
- }
+ char* const path = _path_buffer;
// append the individual substrings
- jio_snprintf(chunk_path, chunkname_max_len, "%s%s%s%s", repository_path, os::file_separator(), date_time_buffer, chunk_file_jfr_ext);
- return chunk_path;
-}
-
-static fio_fd emergency_dump_file_descriptor() {
- 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;
- 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);
+ const int result = jio_snprintf(path,
+ _max_path_buffer_size,
+ "%s%s%s%s",
+ repository_path,
+ os::file_separator(),
+ date_time_buffer,
+ chunk_file_jfr_ext);
+ return result == -1 ? NULL : path;
+}
+
+const char* JfrEmergencyDump::chunk_path(const char* repository_path) {
+ if (repository_path == NULL) {
+ if (!open_emergency_dump_file()) {
+ return NULL;
+ }
+ // We can directly use the emergency dump file name as the chunk.
+ // The chunk writer will open its own fd so we close this descriptor.
+ close_emergency_dump_file();
+ assert(!is_path_empty(), "invariant");
+ return _path_buffer;
}
+ return create_emergency_chunk_path(repository_path);
}
/*
* We are just about to exit the VM, so we will be very aggressive
* at this point in order to increase overall success of dumping jfr data.
@@ -441,34 +530,38 @@
}
}
};
+static void post_events(bool exception_handler) {
+ if (exception_handler) {
+ EventShutdown e;
+ e.set_reason("VM Error");
+ e.commit();
+ } else {
+ // OOM
+ LeakProfiler::emit_events(max_jlong, false);
+ }
+ EventDumpReason event;
+ event.set_reason(exception_handler ? "Crash" : "Out of Memory");
+ event.set_recordingId(-1);
+ event.commit();
+}
+
void JfrEmergencyDump::on_vm_shutdown(bool exception_handler) {
if (!guard_reentrancy()) {
return;
}
-
Thread* thread = Thread::current_or_null_safe();
if (thread == NULL) {
return;
}
// Ensure a JavaThread is _thread_in_vm when we make this call
JavaThreadInVM jtivm(thread);
if (!prepare_for_emergency_dump(thread)) {
return;
}
-
- EventDumpReason event;
- if (event.should_commit()) {
- event.set_reason(exception_handler ? "Crash" : "Out of Memory");
- event.set_recordingId(-1);
- event.commit();
- }
- if (!exception_handler) {
- // OOM
- LeakProfiler::emit_events(max_jlong, false);
- }
+ post_events(exception_handler);
const int messages = MSGBIT(MSG_VM_ERROR);
JfrRecorderService service;
service.rotate(messages);
}
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