1 /* $OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $ */
2 /* $NetBSD: uucplock.c,v 1.7 1997/02/11 09:24:08 mrg Exp $ */
5 * SPDX-License-Identifier: BSD-3-Clause
7 * Copyright (c) 1988, 1993
8 * The Regents of the University of California. All rights reserved.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
40 static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
41 static const char rcsid[] = "$OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $";
45 #include <sys/types.h>
47 #include <sys/dirent.h>
55 #include "pathnames.h"
58 * uucp style locking routines
64 uu_lock(char *ttyname)
67 char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
71 (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
72 fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660);
75 * file is already locked
76 * check to see if the process holding the lock still exists
78 fd = open(tbuf, O_RDWR, 0);
81 fprintf(stderr, "Can't open lock file.\n");
84 len = read(fd, text_pid, sizeof(text_pid)-1);
88 fprintf(stderr, "Can't read lock file.\n");
94 if (kill(pid, 0) == 0 || errno != ESRCH) {
95 (void)close(fd); /* process is still running */
99 * The process that locked the file isn't running, so
100 * we'll lock it ourselves
102 fprintf(stderr, "Stale lock on %s PID=%ld... overriding.\n",
104 if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
107 fprintf(stderr, "Can't seek lock file.\n");
110 /* fall out and finish the locking process */
113 (void)snprintf(text_pid, sizeof text_pid, "%10ld\n", (long)pid);
114 len = strlen(text_pid);
115 if (write(fd, text_pid, len) != len) {
118 perror("lock write");
126 uu_unlock(char *ttyname)
128 char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
130 (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
132 return(unlink(tbuf));