2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * $FreeBSD: src/lib/libutil/uucplock.c,v 1.12.2.1 2000/10/09 20:20:52 brian Exp $
34 * $DragonFly: src/lib/libutil/uucplock.c,v 1.2 2003/06/17 04:26:52 dillon Exp $
36 * @(#)uucplock.c 8.1 (Berkeley) 6/6/93
39 #include <sys/types.h>
53 #define LOCKTMP "LCKTMP..%d"
54 #define LOCKFMT "LCK..%s"
56 #define GORET(level, val) { err = errno; uuerr = (val); \
57 goto __CONCAT(ret, level); }
59 /* Forward declarations */
60 static int put_pid (int fd, pid_t pid);
61 static pid_t get_pid (int fd,int *err);
64 * uucp style locking routines
68 uu_lock(const char *ttyname)
72 char lckname[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN],
73 lcktmpname[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
77 (void)snprintf(lcktmpname, sizeof(lcktmpname), _PATH_UUCPLOCK LOCKTMP,
79 (void)snprintf(lckname, sizeof(lckname), _PATH_UUCPLOCK LOCKFMT,
81 if ((tmpfd = creat(lcktmpname, 0664)) < 0)
82 GORET(0, UU_LOCK_CREAT_ERR);
84 for (i = 0; i < MAXTRIES; i++) {
85 if (link (lcktmpname, lckname) < 0) {
87 GORET(1, UU_LOCK_LINK_ERR);
89 * file is already locked
90 * check to see if the process holding the lock
93 if ((fd = open(lckname, O_RDONLY)) < 0)
94 GORET(1, UU_LOCK_OPEN_ERR);
96 if ((pid_old = get_pid (fd, &err)) == -1)
97 GORET(2, UU_LOCK_READ_ERR);
101 if (kill(pid_old, 0) == 0 || errno != ESRCH)
102 GORET(1, UU_LOCK_INUSE);
104 * The process that locked the file isn't running, so
105 * we'll lock it ourselves
107 (void)unlink(lckname);
109 if (!put_pid (tmpfd, pid))
110 GORET(3, UU_LOCK_WRITE_ERR);
114 GORET(1, (i >= MAXTRIES) ? UU_LOCK_TRY_ERR : UU_LOCK_OK);
117 (void)unlink(lckname);
123 (void)unlink(lcktmpname);
130 uu_lock_txfr(const char *ttyname, pid_t pid)
133 char lckname[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
135 snprintf(lckname, sizeof(lckname), _PATH_UUCPLOCK LOCKFMT, ttyname);
137 if ((fd = open(lckname, O_RDWR)) < 0)
138 return UU_LOCK_OWNER_ERR;
139 if (get_pid(fd, &err) != getpid())
140 err = UU_LOCK_OWNER_ERR;
142 lseek(fd, 0, SEEK_SET);
143 err = put_pid(fd, pid) ? 0 : UU_LOCK_WRITE_ERR;
151 uu_unlock(const char *ttyname)
153 char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
155 (void)snprintf(tbuf, sizeof(tbuf), _PATH_UUCPLOCK LOCKFMT, ttyname);
160 uu_lockerr(int uu_lockresult)
162 static char errbuf[128];
165 switch (uu_lockresult) {
167 return "device in use";
170 case UU_LOCK_OPEN_ERR:
171 fmt = "open error: %s";
173 case UU_LOCK_READ_ERR:
174 fmt = "read error: %s";
176 case UU_LOCK_CREAT_ERR:
177 fmt = "creat error: %s";
179 case UU_LOCK_WRITE_ERR:
180 fmt = "write error: %s";
182 case UU_LOCK_LINK_ERR:
183 fmt = "link error: %s";
185 case UU_LOCK_TRY_ERR:
186 fmt = "too many tries: %s";
188 case UU_LOCK_OWNER_ERR:
189 fmt = "not locking process: %s";
192 fmt = "undefined error: %s";
196 (void)snprintf(errbuf, sizeof(errbuf), fmt, strerror(errno));
201 put_pid(int fd, pid_t pid)
206 len = sprintf (buf, "%10d\n", (int)pid);
207 return write (fd, buf, len) == len;
211 get_pid(int fd, int *err)
217 bytes_read = read (fd, buf, sizeof (buf) - 1);
218 if (bytes_read > 0) {
219 buf[bytes_read] = '\0';
220 pid = strtol (buf, (char **) NULL, 10);
223 *err = bytes_read ? errno : EINVAL;
228 /* end of uucplock.c */