/*
flock - acquires a file lock and executes a command with the lock held.
Usage: flock [--shared | --timeout=seconds] lockfile program [args...]
Written by Adam J. Richter
Copyright (C) 2004 Yggdrasil Computing, Inc.
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <sys/file.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <getopt.h>
#include <unistd.h>
#include <stdlib.h> /* exit */
#include <signal.h> /* kill */
#include <stdio.h>
#include "nls.h"
static int non_blocking = 0;
static int shared = LOCK_EX;
static const struct option options[] = {
{"shared", no_argument, &shared, LOCK_SH },
{"timeout", required_argument, NULL, 't' },
{NULL, 0, NULL, 0 },
};
int main(int argc, char **argv)
{
int fd;
int opt;
int pid;
int child_status;
int option_index;
int timeout = 0;
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
do {
opt = getopt_long(argc, argv, "+", options, &option_index);
switch(opt) {
case '?':
fprintf (stderr,
_("flock: unknown option, aborting.\n"));
exit(1);
break;
case 't':
timeout = atoi(optarg);
if (timeout == 0)
non_blocking |= LOCK_NB;
break;
default:
break;
}
} while (opt != -1);
argc -= optind;
argv += optind;
if (argc < 2) {
fprintf(stderr,
_("Usage flock [--shared] [--timeout=seconds] "
"filename command {arg arg...}\n"));
exit(2);
}
fd = open(argv[0], O_RDONLY);
if (fd < 0) {
perror(argv[0]);
exit(3);
}
alarm(timeout);
if (flock(fd, shared | non_blocking) != 0) {
perror("flock");
exit(4);
}
alarm(0);
pid = fork();
if (pid < 0) {
perror("fork");
exit(5);
}
if (pid == 0) {
execvp(argv[1], argv+1);
perror(argv[1]);
exit(6);
}
waitpid(pid, &child_status, 0);
/* flock(fd, LOCK_UN); */
/* No need to explicitly release the flock, since we are just
going to exit now anyhow. */
/* Lame attempt to simulate child's mode of death. */
if (WIFSIGNALED(child_status))
kill(0, WTERMSIG(child_status));
return WEXITSTATUS(child_status);
}
