2 CTDB mutex fcntl lock file helper
4 Copyright (C) Martin Schwenke 2015
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, see <http://www.gnu.org/licenses/>.
21 #include "system/filesys.h"
22 #include "system/network.h"
24 /* protocol.h is just needed for ctdb_sock_addr, which is used in system.h */
25 #include "protocol/protocol.h"
26 #include "common/system.h"
28 static char *progname
= NULL
;
30 static char fcntl_lock(const char *file
)
35 fd
= open(file
, O_RDWR
|O_CREAT
, 0600);
37 fprintf(stderr
, "%s: Unable to open %s - (%s)\n",
38 progname
, file
, strerror(errno
));
42 lock
.l_type
= F_WRLCK
;
43 lock
.l_whence
= SEEK_SET
;
48 if (fcntl(fd
, F_SETLK
, &lock
) != 0) {
49 int saved_errno
= errno
;
52 if (saved_errno
== EACCES
||
53 saved_errno
== EAGAIN
) {
54 /* Lock contention, fail silently */
58 /* Log an error for any other failure */
60 "%s: Failed to get lock on '%s' - (%s)\n",
61 progname
, file
, strerror(saved_errno
));
68 int main(int argc
, char *argv
[])
72 const char *file
= NULL
;
77 fprintf(stderr
, "Usage: %s <file>\n", progname
);
84 result
= fcntl_lock(file
);
85 sys_write(STDOUT_FILENO
, &result
, 1);
87 ctdb_wait_for_process_to_exit(ppid
);