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
|
/*
*
* Copyright (c) 2008 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include "qpid/sys/LockFile.h"
#include "qpid/sys/posix/PidFile.h"
#include <string>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "qpid/sys/posix/check.h"
namespace qpid {
namespace sys {
class LockFilePrivate {
friend class LockFile;
friend class PidFile;
int fd;
public:
LockFilePrivate(int f) : fd(f) {}
};
LockFile::LockFile(const std::string& path_, bool create)
: path(path_), created(create) {
errno = 0;
int flags=create ? O_WRONLY|O_CREAT|O_NOFOLLOW : O_RDWR;
int fd = ::open(path.c_str(), flags, 0644);
if (fd < 0) throw ErrnoException("Cannot open " + path, errno);
if (::lockf(fd, F_TLOCK, 0) < 0) {
::close(fd);
throw ErrnoException("Cannot lock " + path, errno);
}
impl.reset(new LockFilePrivate(fd));
}
LockFile::~LockFile() {
if (impl) {
int f = impl->fd;
if (f >= 0) {
int unused_ret;
unused_ret = ::lockf(f, F_ULOCK, 0); // Suppress warnings about ignoring return value.
::close(f);
impl->fd = -1;
}
}
}
int LockFile::read(void* bytes, size_t len) const {
if (!impl)
throw Exception("Lock file not open: " + path);
ssize_t rc = ::read(impl->fd, bytes, len);
if ((ssize_t)len > rc) {
throw Exception("Cannot read lock file: " + path);
}
return rc;
}
int LockFile::write(void* bytes, size_t len) const {
if (!impl)
throw Exception("Lock file not open: " + path);
ssize_t rc = ::write(impl->fd, bytes, len);
if ((ssize_t)len > rc) {
throw Exception("Cannot write lock file: " + path);
}
return rc;
}
PidFile::PidFile(const std::string& path_, bool create):
LockFile(path_, create)
{}
pid_t PidFile::readPid(void) const {
pid_t pid;
int desired_read = sizeof(pid_t);
read(&pid, desired_read);
return pid;
}
void PidFile::writePid(void) {
pid_t pid = getpid();
int desired_write = sizeof(pid_t);
write(&pid, desired_write);
}
}} /* namespace qpid::sys */
|
