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 $ */ 3 4 /* 5 * Copyright (c) 1988, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93"; 39 static const char rcsid[] = "$OpenBSD: uucplock.c,v 1.11 2006/03/16 19:32:46 deraadt Exp $"; 40 #endif 41 #endif /* not lint */ 42 43 #include <sys/types.h> 44 #include <sys/file.h> 45 #include <sys/dirent.h> 46 #include <stdio.h> 47 #include <string.h> 48 #include <signal.h> 49 #include <unistd.h> 50 #include <stdlib.h> 51 #include <errno.h> 52 #include "tip.h" 53 #include "pathnames.h" 54 55 /* 56 * uucp style locking routines 57 * return: 0 - success 58 * -1 - failure 59 */ 60 61 int 62 uu_lock(char *ttyname) 63 { 64 int fd, len; 65 char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN]; 66 char text_pid[81]; 67 pid_t pid; 68 69 (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname); 70 fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660); 71 if (fd < 0) { 72 /* 73 * file is already locked 74 * check to see if the process holding the lock still exists 75 */ 76 fd = open(tbuf, O_RDWR, 0); 77 if (fd < 0) { 78 perror(tbuf); 79 fprintf(stderr, "Can't open lock file.\n"); 80 return(-1); 81 } 82 len = read(fd, text_pid, sizeof(text_pid)-1); 83 if (len<=0) { 84 perror(tbuf); 85 (void)close(fd); 86 fprintf(stderr, "Can't read lock file.\n"); 87 return(-1); 88 } 89 text_pid[len] = 0; 90 pid = atol(text_pid); 91 92 if (kill(pid, 0) == 0 || errno != ESRCH) { 93 (void)close(fd); /* process is still running */ 94 return(-1); 95 } 96 /* 97 * The process that locked the file isn't running, so 98 * we'll lock it ourselves 99 */ 100 fprintf(stderr, "Stale lock on %s PID=%ld... overriding.\n", 101 ttyname, (long)pid); 102 if (lseek(fd, (off_t)0, SEEK_SET) < 0) { 103 perror(tbuf); 104 (void)close(fd); 105 fprintf(stderr, "Can't seek lock file.\n"); 106 return(-1); 107 } 108 /* fall out and finish the locking process */ 109 } 110 pid = getpid(); 111 (void)snprintf(text_pid, sizeof text_pid, "%10ld\n", (long)pid); 112 len = strlen(text_pid); 113 if (write(fd, text_pid, len) != len) { 114 (void)close(fd); 115 (void)unlink(tbuf); 116 perror("lock write"); 117 return(-1); 118 } 119 (void)close(fd); 120 return(0); 121 } 122 123 int 124 uu_unlock(char *ttyname) 125 { 126 char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN]; 127 128 (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname); 129 unexcl(); 130 return(unlink(tbuf)); 131 } 132