/* $OpenBSD: uucplock.c,v 1.2 1996/06/26 05:40:49 deraadt Exp $ */ /* $NetBSD: uucplock.c,v 1.6 1995/09/26 06:02:14 jtc 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. */ #ifndef lint #if 0 static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93"; #endif static char rcsid[] = "$OpenBSD: uucplock.c,v 1.2 1996/06/26 05:40:49 deraadt Exp $"; #endif /* not lint */ #include <stdio.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/file.h> #include <sys/dir.h> #include <errno.h> #include "pathnames.h" /* * uucp style locking routines * return: 0 - success * -1 - failure */ uu_lock(ttyname) char *ttyname; { int fd, pid; char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN]; char text_pid[81]; int len; (void)sprintf(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=%d... overriding.\n", ttyname, pid); if (lseek(fd, (off_t)0, L_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(); sprintf(text_pid, "%10d\n", 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); } uu_unlock(ttyname) char *ttyname; { char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN]; (void)sprintf(tbuf, _PATH_LOCKDIRNAME, ttyname); return(unlink(tbuf)); }