1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/**
* Copyright (C) 2014 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage
#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/db/storage/paths.h"
#include "mongo/platform/process_id.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace {
const std::string kLockFileBasename = "mongod.lock";
} // 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)
: _dbpath(dbpath),
_filespec((boost::filesystem::path(_dbpath) / kLockFileBasename).string()),
_uncleanShutdown(boost::filesystem::exists(_filespec) &&
boost::filesystem::file_size(_filespec) > 0),
_lockFileHandle(new LockFileHandle()) {}
StorageEngineLockFile::~StorageEngineLockFile() {}
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,
str::stream() << "Data directory " << _dbpath << " not found.");
}
} 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) {
int errorcode = errno;
if (errorcode == 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 lock file: " << _filespec << ' '
<< errnoWithDescription(errorcode)
<< " Is a mongod instance already running?");
}
#if !defined(__sun)
int ret = ::flock(lockFile, LOCK_EX | LOCK_NB);
#else
struct flock fileLockInfo = {0};
fileLockInfo.l_type = F_WRLCK;
fileLockInfo.l_whence = SEEK_SET;
int ret = ::fcntl(lockFile, F_SETLK, &fileLockInfo);
#endif // !defined(__sun)
if (ret != 0) {
int errorcode = errno;
::close(lockFile);
return Status(ErrorCodes::DBPathInUse,
str::stream() << "Unable to lock file: " << _filespec << ' '
<< errnoWithDescription(errorcode)
<< ". Is a mongod instance already running?");
}
_lockFileHandle->_fd = lockFile;
return Status::OK();
}
void StorageEngineLockFile::close() {
if (!_lockFileHandle->isValid()) {
return;
}
::close(_lockFileHandle->_fd);
_lockFileHandle->clear();
}
Status StorageEngineLockFile::writePid() {
if (!_lockFileHandle->isValid()) {
return Status(ErrorCodes::FileNotOpen,
str::stream() << "Unable to write process ID to " << _filespec
<< " because file has not been opened.");
}
if (::ftruncate(_lockFileHandle->_fd, 0)) {
int errorcode = errno;
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write process id to file (ftruncate failed): "
<< _filespec
<< ' '
<< errnoWithDescription(errorcode));
}
ProcessId pid = ProcessId::getCurrent();
std::stringstream ss;
ss << pid << std::endl;
std::string pidStr = ss.str();
int bytesWritten = ::write(_lockFileHandle->_fd, pidStr.c_str(), pidStr.size());
if (bytesWritten < 0) {
int errorcode = errno;
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write process id " << pid.toString()
<< " to file: "
<< _filespec
<< ' '
<< errnoWithDescription(errorcode));
} else if (bytesWritten == 0) {
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write process id " << pid.toString()
<< " to file: "
<< _filespec
<< " no data written.");
}
if (::fsync(_lockFileHandle->_fd)) {
int errorcode = errno;
return Status(ErrorCodes::FileStreamFailed,
str::stream() << "Unable to write process id " << pid.toString()
<< " to file (fsync failed): "
<< _filespec
<< ' '
<< errnoWithDescription(errorcode));
}
flushMyDirectory(_filespec);
return Status::OK();
}
void StorageEngineLockFile::clearPidAndUnlock() {
if (!_lockFileHandle->isValid()) {
return;
}
log() << "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)) {
int errorcode = errno;
log() << "couldn't remove fs lock " << errnoWithDescription(errorcode);
}
#if !defined(__sun)
::flock(_lockFileHandle->_fd, LOCK_UN);
#else
struct flock fileLockInfo = {0};
fileLockInfo.l_type = F_UNLCK;
fileLockInfo.l_whence = SEEK_SET;
::fcntl(_lockFileHandle->_fd, F_SETLK, &fileLockInfo);
#endif // !defined(__sun)
}
} // namespace mongo
|