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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/storage/storage_engine_lock_file.h"
#include <boost/filesystem.hpp>
#include <fcntl.h>
#include <ostream>
#include <sstream>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "mongo/logv2/log.h"
#include "mongo/util/str.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kStorage
namespace mongo {
namespace {
void flushMyDirectory(const boost::filesystem::path& file) {
#ifdef __linux__ // this isn't needed elsewhere
static bool _warnedAboutFilesystem = false;
// if called without a fully qualified path it asserts; that makes mongoperf fail.
// so make a warning. need a better solution longer term.
// massert(40389, str::stream() << "Couldn't find parent dir for file: " << file.string(),);
if (!file.has_branch_path()) {
LOGV2(22274,
"warning flushMyDirectory couldn't find parent dir for file: {file}",
"flushMyDirectory couldn't find parent dir for file",
"file"_attr = file.generic_string());
return;
}
boost::filesystem::path dir = file.branch_path(); // parent_path in new boosts
LOGV2_DEBUG(22275, 1, "flushing directory {dir_string}", "dir_string"_attr = dir.string());
int fd = ::open(dir.string().c_str(), O_RDONLY); // DO NOT THROW OR ASSERT BEFORE CLOSING
if (fd < 0) {
auto ec = lastPosixError();
msgasserted(40387,
str::stream() << "Couldn't open directory '" << dir.string()
<< "' for flushing: " << errorMessage(ec));
}
if (fsync(fd) != 0) {
auto ec = lastPosixError();
if (ec == posixError(EINVAL)) { // indicates filesystem does not support synchronization
if (!_warnedAboutFilesystem) {
LOGV2_OPTIONS(
22276,
{logv2::LogTag::kStartupWarnings},
"This file system is not supported. For further information see: "
"http://dochub.mongodb.org/core/unsupported-filesystems Please notify MongoDB, "
"Inc. if an unlisted filesystem generated this warning");
_warnedAboutFilesystem = true;
}
} else {
close(fd);
massert(40388,
str::stream() << "Couldn't fsync directory '" << dir.string()
<< "': " << errorMessage(ec),
false);
}
}
close(fd);
#endif
}
} // namespace
class StorageEngineLockFile::LockFileHandle {
public:
static const int kInvalidFd = -1;
LockFileHandle() : _fd(kInvalidFd) {}
bool isValid() const {
return _fd != kInvalidFd;
}
void clear() {
_fd = kInvalidFd;
}
int _fd;
};
StorageEngineLockFile::StorageEngineLockFile(const std::string& dbpath, StringData fileName)
: _dbpath(dbpath),
_filespec((boost::filesystem::path(_dbpath) / fileName.toString()).string()),
_uncleanShutdown(boost::filesystem::exists(_filespec) &&
boost::filesystem::file_size(_filespec) > 0),
_lockFileHandle(new LockFileHandle()) {}
StorageEngineLockFile::~StorageEngineLockFile() {
close();
}
std::string StorageEngineLockFile::getFilespec() const {
return _filespec;
}
bool StorageEngineLockFile::createdByUncleanShutdown() const {
return _uncleanShutdown;
}
Status StorageEngineLockFile::open() {
try {
if (!boost::filesystem::exists(_dbpath)) {
return Status(ErrorCodes::NonExistentPath, _getNonExistentPathMessage());
}
} catch (const std::exception& ex) {
return Status(ErrorCodes::UnknownError,
str::stream() << "Unable to check existence of data directory " << _dbpath
<< ": " << ex.what());
}
// Use file permissions 644
int lockFile =
::open(_filespec.c_str(), O_RDWR | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (lockFile < 0) {
auto ec = lastPosixError();
if (ec == posixError(EACCES)) {
return Status(ErrorCodes::IllegalOperation,
str::stream()
<< "Attempted to create a lock file on a read-only directory: "
<< _dbpath);
}
return Status(ErrorCodes::DBPathInUse,
str::stream() << "Unable to create/open the lock file: " << _filespec << " ("
<< errorMessage(ec) << ")."
<< " Ensure the user executing mongod is the owner of the lock "
"file and has the appropriate permissions. Also make sure "
"that another mongod instance is not already running on the "
<< _dbpath << " directory");
}
int ret = ::flock(lockFile, LOCK_EX | LOCK_NB);
if (ret != 0) {
auto ec = lastPosixError();
::close(lockFile);
return Status(ErrorCodes::DBPathInUse,
str::stream() << "Unable to lock the lock file: " << _filespec << " ("
<< errorMessage(ec) << ")."
<< " Another mongod instance is already running on the "
<< _dbpath << " directory");
}
_lockFileHandle->_fd = lockFile;
return Status::OK();
}
void StorageEngineLockFile::close() {
if (!_lockFileHandle->isValid()) {
return;
}
::flock(_lockFileHandle->_fd, LOCK_UN);
::close(_lockFileHandle->_fd);
_lockFileHandle->clear();
}
Status StorageEngineLockFile::writeString(StringData str) {
if (!_lockFileHandle->isValid()) {
return Status(ErrorCodes::FileNotOpen,
str::stream() << "Unable to write string to " << _filespec
<< " because file has not been opened.");
}
if (::ftruncate(_lockFileHandle->_fd, 0)) {
auto ec = lastPosixError();
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write string to file (ftruncate failed): "
<< _filespec << ' ' << errorMessage(ec));
}
int bytesWritten = ::write(_lockFileHandle->_fd, str.rawData(), str.size());
if (bytesWritten < 0) {
auto ec = lastPosixError();
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write string " << str << " to file: " << _filespec
<< ' ' << errorMessage(ec));
} else if (bytesWritten == 0) {
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write string " << str << " to file: " << _filespec
<< " no data written.");
}
if (::fsync(_lockFileHandle->_fd)) {
auto ec = lastPosixError();
return Status(ErrorCodes::FileStreamFailed,
str::stream()
<< "Unable to write process id " << str
<< " to file (fsync failed): " << _filespec << ' ' << errorMessage(ec));
}
flushMyDirectory(_filespec);
return Status::OK();
}
void StorageEngineLockFile::clearPidAndUnlock() {
if (!_lockFileHandle->isValid()) {
return;
}
LOGV2(22279, "shutdown: removing fs lock...");
// This ought to be an unlink(), but Eliot says the last
// time that was attempted, there was a race condition
// with StorageEngineLockFile::open().
if (::ftruncate(_lockFileHandle->_fd, 0)) {
auto ec = lastPosixError();
LOGV2(22280, "Couldn't remove fs lock", "error"_attr = errorMessage(ec));
}
close();
}
} // namespace mongo
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