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Commit | Line | Data |
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5e97c3fc | 1 | /* |
2 | * lxc: linux Container library | |
3 | * | |
4 | * (C) Copyright IBM Corp. 2007, 2008 | |
5 | * | |
6 | * Authors: | |
7 | * Daniel Lezcano <dlezcano at fr.ibm.com> | |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
22 | */ | |
23 | ||
24 | #define _GNU_SOURCE | |
25 | #include <stdio.h> | |
26 | #undef _GNU_SOURCE | |
27 | #include <errno.h> | |
28 | #include <unistd.h> | |
29 | #include <stdlib.h> | |
30 | #include <sys/file.h> | |
31 | #include <lxc.h> | |
32 | ||
33 | int lxc_get_lock(const char *name) | |
34 | { | |
35 | char *lock; | |
36 | int fd, ret; | |
37 | ||
38 | asprintf(&lock, LXCPATH "/%s", name); | |
39 | fd = open(lock, O_RDONLY|O_DIRECTORY, S_IRUSR|S_IWUSR); | |
40 | if (fd < 0) { | |
41 | ret = -errno; | |
42 | goto out; | |
43 | } | |
44 | ||
c2cc9f0a | 45 | fcntl(fd, F_SETFD, FD_CLOEXEC); |
46 | ||
5e97c3fc | 47 | if (flock(fd, LOCK_EX|LOCK_NB)) { |
48 | ret = errno == EWOULDBLOCK ? 0 : -errno; | |
49 | close(fd); | |
50 | goto out; | |
51 | } | |
52 | ||
53 | ret = fd; | |
54 | out: | |
55 | free(lock); | |
56 | return ret; | |
57 | } | |
58 | ||
59 | void lxc_put_lock(int lock) | |
60 | { | |
61 | flock(lock, LOCK_UN); | |
62 | close(lock); | |
63 | } |