mirror of
https://github.com/samba-team/samba.git
synced 2024-12-22 13:34:15 +03:00
bdc049dfce
Signed-off-by: Martin Schwenke <martin@meltin.net> Reviewed-by: Amitay Isaacs <amitay@gmail.com> Autobuild-User(master): Amitay Isaacs <amitay@samba.org> Autobuild-Date(master): Tue Nov 29 11:22:40 CET 2016 on sn-devel-144
113 lines
2.5 KiB
C
113 lines
2.5 KiB
C
/*
|
|
CTDB mutex fcntl lock file helper
|
|
|
|
Copyright (C) Martin Schwenke 2015
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
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 General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "replace.h"
|
|
#include "system/filesys.h"
|
|
#include "system/network.h"
|
|
|
|
#include "lib/util/sys_rw.h"
|
|
|
|
/* protocol.h is just needed for ctdb_sock_addr, which is used in system.h */
|
|
#include "protocol/protocol.h"
|
|
#include "common/system.h"
|
|
|
|
static char *progname = NULL;
|
|
|
|
static char fcntl_lock(const char *file, int *outfd)
|
|
{
|
|
int fd;
|
|
struct flock lock;
|
|
|
|
fd = open(file, O_RDWR|O_CREAT, 0600);
|
|
if (fd == -1) {
|
|
fprintf(stderr, "%s: Unable to open %s - (%s)\n",
|
|
progname, file, strerror(errno));
|
|
return '3';
|
|
}
|
|
|
|
lock.l_type = F_WRLCK;
|
|
lock.l_whence = SEEK_SET;
|
|
lock.l_start = 0;
|
|
lock.l_len = 1;
|
|
lock.l_pid = 0;
|
|
|
|
if (fcntl(fd, F_SETLK, &lock) != 0) {
|
|
int saved_errno = errno;
|
|
close(fd);
|
|
fd = -1;
|
|
if (saved_errno == EACCES ||
|
|
saved_errno == EAGAIN) {
|
|
/* Lock contention, fail silently */
|
|
return '1';
|
|
}
|
|
|
|
/* Log an error for any other failure */
|
|
fprintf(stderr,
|
|
"%s: Failed to get lock on '%s' - (%s)\n",
|
|
progname, file, strerror(saved_errno));
|
|
return '3';
|
|
}
|
|
|
|
*outfd = fd;
|
|
|
|
return '0';
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
char result;
|
|
int ppid;
|
|
const char *file = NULL;
|
|
int fd = -1;
|
|
|
|
progname = argv[0];
|
|
|
|
if (argc != 2) {
|
|
fprintf(stderr, "Usage: %s <file>\n", progname);
|
|
exit(1);
|
|
}
|
|
|
|
ppid = getppid();
|
|
|
|
if (ppid == 1) {
|
|
/* The original parent is gone and the process has
|
|
* been reparented to init. This can happen if the
|
|
* helper is started just as the parent is killed
|
|
* during shutdown. The error message doesn't need to
|
|
* be stellar, since there won't be anything around to
|
|
* capture and log it...
|
|
*/
|
|
fprintf(stderr, "%s: PPID == 1\n", progname);
|
|
exit(1);
|
|
}
|
|
|
|
file = argv[1];
|
|
|
|
result = fcntl_lock(file, &fd);
|
|
sys_write(STDOUT_FILENO, &result, 1);
|
|
|
|
ctdb_wait_for_process_to_exit(ppid);
|
|
|
|
if (fd != -1) {
|
|
close(fd);
|
|
}
|
|
|
|
return 0;
|
|
}
|