networking/udhcp/pidfile.c

/* vi: set sw=4 ts=4: */
/* pidfile.c
 *
 * Functions to assist in the writing and removing of pidfiles.
 *
 * Russ Dill <Russ.Dill@asu.edu> September 2001
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "common.h"


static const char *saved_pidfile;

static void pidfile_delete(void)
{
	if (saved_pidfile) unlink(saved_pidfile);
}


int pidfile_acquire(const char *pidfile)
{
	int pid_fd;
	if (!pidfile) return -1;

	pid_fd = open(pidfile, O_CREAT|O_WRONLY|O_TRUNC, 0644);
	if (pid_fd < 0) {
		bb_perror_msg("cannot open pidfile %s", pidfile);
	} else {
		lockf(pid_fd, F_LOCK, 0);
		if (!saved_pidfile)
			atexit(pidfile_delete);
		saved_pidfile = pidfile;
	}

	return pid_fd;
}


void pidfile_write_release(int pid_fd)
{
	FILE *out;

	if (pid_fd < 0) return;

	out = fdopen(pid_fd, "w");
	if (out) {
		fprintf(out, "%d\n", getpid());
		fclose(out);
	}
	lockf(pid_fd, F_UNLCK, 0);
	close(pid_fd);
}
1	/* vi: set sw=4 ts=4: */
2	/* pidfile.c
3	*
4	* Functions to assist in the writing and removing of pidfiles.
5	*
6	* Russ Dill <Russ.Dill@asu.edu> September 2001
7	*
8	* This program is free software; you can redistribute it and/or modify
9	* it under the terms of the GNU General Public License as published by
10	* the Free Software Foundation; either version 2 of the License, or
11	* (at your option) any later version.
12	*
13	* This program is distributed in the hope that it will be useful,
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16	* GNU General Public License for more details.
17	*
18	* You should have received a copy of the GNU General Public License
19	* along with this program; if not, write to the Free Software
20	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21	*/
22
23	#include "common.h"
24
25
26	static const char *saved_pidfile;
27
28	static void pidfile_delete(void)
29	{
30	if (saved_pidfile) unlink(saved_pidfile);
31	}
32
33
34	int pidfile_acquire(const char *pidfile)
35	{
36	int pid_fd;
37	if (!pidfile) return -1;
38
39	pid_fd = open(pidfile, O_CREAT\|O_WRONLY\|O_TRUNC, 0644);
40	if (pid_fd < 0) {
41	bb_perror_msg("cannot open pidfile %s", pidfile);
42	} else {
43	lockf(pid_fd, F_LOCK, 0);
44	if (!saved_pidfile)
45	atexit(pidfile_delete);
46	saved_pidfile = pidfile;
47	}
48
49	return pid_fd;
50	}
51
52
53	void pidfile_write_release(int pid_fd)
54	{
55	FILE *out;
56
57	if (pid_fd < 0) return;
58
59	out = fdopen(pid_fd, "w");
60	if (out) {
61	fprintf(out, "%d\n", getpid());
62	fclose(out);
63	}
64	lockf(pid_fd, F_UNLCK, 0);
65	close(pid_fd);
66	}