Annotation of src/usr.bin/tip/uucplock.c, Revision 1.10
1.10 ! millert 1: /* $OpenBSD: uucplock.c,v 1.9 2002/06/12 06:07:16 mpech Exp $ */
1.3 millert 2: /* $NetBSD: uucplock.c,v 1.7 1997/02/11 09:24:08 mrg Exp $ */
1.1 deraadt 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.
1.10 ! millert 16: * 3. Neither the name of the University nor the names of its contributors
1.1 deraadt 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: #ifndef lint
34: #if 0
35: static char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
36: #endif
1.10 ! millert 37: static const char rcsid[] = "$OpenBSD: uucplock.c,v 1.9 2002/06/12 06:07:16 mpech Exp $";
1.1 deraadt 38: #endif /* not lint */
39:
1.5 deraadt 40: #include <sys/types.h>
41: #include <sys/file.h>
42: #include <sys/dir.h>
1.1 deraadt 43: #include <stdio.h>
44: #include <string.h>
1.5 deraadt 45: #include <signal.h>
1.1 deraadt 46: #include <unistd.h>
1.5 deraadt 47: #include <stdlib.h>
1.1 deraadt 48: #include <errno.h>
49: #include "pathnames.h"
50:
51: /*
52: * uucp style locking routines
53: * return: 0 - success
54: * -1 - failure
55: */
56:
1.5 deraadt 57: int
1.1 deraadt 58: uu_lock(ttyname)
59: char *ttyname;
60: {
1.8 deraadt 61: int fd, len;
1.1 deraadt 62: char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
63: char text_pid[81];
1.8 deraadt 64: pid_t pid;
1.1 deraadt 65:
1.4 deraadt 66: (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
1.1 deraadt 67: fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL, 0660);
68: if (fd < 0) {
69: /*
70: * file is already locked
71: * check to see if the process holding the lock still exists
72: */
73: fd = open(tbuf, O_RDWR, 0);
74: if (fd < 0) {
75: perror(tbuf);
76: fprintf(stderr, "Can't open lock file.\n");
77: return(-1);
78: }
79: len = read(fd, text_pid, sizeof(text_pid)-1);
80: if(len<=0) {
81: perror(tbuf);
82: (void)close(fd);
83: fprintf(stderr, "Can't read lock file.\n");
84: return(-1);
85: }
86: text_pid[len] = 0;
87: pid = atol(text_pid);
88:
89: if (kill(pid, 0) == 0 || errno != ESRCH) {
90: (void)close(fd); /* process is still running */
91: return(-1);
92: }
93: /*
94: * The process that locked the file isn't running, so
95: * we'll lock it ourselves
96: */
1.9 mpech 97: fprintf(stderr, "Stale lock on %s PID=%ld... overriding.\n",
98: ttyname, (long)pid);
1.6 millert 99: if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
1.1 deraadt 100: perror(tbuf);
101: (void)close(fd);
102: fprintf(stderr, "Can't seek lock file.\n");
103: return(-1);
104: }
105: /* fall out and finish the locking process */
106: }
107: pid = getpid();
1.8 deraadt 108: (void)snprintf(text_pid, sizeof text_pid, "%10ld\n", (long)pid);
1.1 deraadt 109: len = strlen(text_pid);
110: if (write(fd, text_pid, len) != len) {
111: (void)close(fd);
112: (void)unlink(tbuf);
113: perror("lock write");
114: return(-1);
115: }
116: (void)close(fd);
117: return(0);
118: }
119:
1.5 deraadt 120: int
1.1 deraadt 121: uu_unlock(ttyname)
122: char *ttyname;
123: {
124: char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
125:
1.4 deraadt 126: (void)snprintf(tbuf, sizeof tbuf, _PATH_LOCKDIRNAME, ttyname);
1.1 deraadt 127: return(unlink(tbuf));
128: }
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