/usr.bin/tip/tip/uucplock.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 131 lines · 77 code · 10 blank · 44 comment · 10 complexity · e9b738232ddba928db9d4308d730d4e5 MD5 · raw file
- /* $OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $ */
- /* $NetBSD: uucplock.c,v 1.7 1997/02/11 09:24:08 mrg Exp $ */
- /*
- * Copyright (c) 1988, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #include <sys/cdefs.h>
- __FBSDID("$FreeBSD$");
- #ifndef lint
- #if 0
- static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
- static const char rcsid[] = "$OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $";
- #endif
- #endif /* not lint */
- #include <sys/types.h>
- #include <sys/file.h>
- #include <sys/dirent.h>
- #include <stdio.h>
- #include <string.h>
- #include <signal.h>
- #include <unistd.h>
- #include <stdlib.h>
- #include <errno.h>
- #include "tip.h"
- #include "pathnames.h"
- /*
- * uucp style locking routines
- * return: 0 - success
- * -1 - failure
- */
- int
- uu_lock(char *ttyname)
- {
- int fd, len;
- char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
- char text_pid[81];
- pid_t pid;
- (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
- fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660);
- if (fd < 0) {
- /*
- * file is already locked
- * check to see if the process holding the lock still exists
- */
- fd = open(tbuf, O_RDWR, 0);
- if (fd < 0) {
- perror(tbuf);
- fprintf(stderr, "Can't open lock file.\n");
- return(-1);
- }
- len = read(fd, text_pid, sizeof(text_pid)-1);
- if (len<=0) {
- perror(tbuf);
- (void)close(fd);
- fprintf(stderr, "Can't read lock file.\n");
- return(-1);
- }
- text_pid[len] = 0;
- pid = atol(text_pid);
- if (kill(pid, 0) == 0 || errno != ESRCH) {
- (void)close(fd); /* process is still running */
- return(-1);
- }
- /*
- * The process that locked the file isn't running, so
- * we'll lock it ourselves
- */
- fprintf(stderr, "Stale lock on %s PID=%ld... overriding.\n",
- ttyname, (long)pid);
- if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
- perror(tbuf);
- (void)close(fd);
- fprintf(stderr, "Can't seek lock file.\n");
- return(-1);
- }
- /* fall out and finish the locking process */
- }
- pid = getpid();
- (void)snprintf(text_pid, sizeof text_pid, "%10ld\n", (long)pid);
- len = strlen(text_pid);
- if (write(fd, text_pid, len) != len) {
- (void)close(fd);
- (void)unlink(tbuf);
- perror("lock write");
- return(-1);
- }
- (void)close(fd);
- return(0);
- }
- int
- uu_unlock(char *ttyname)
- {
- char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
- (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
- unexcl();
- return(unlink(tbuf));
- }