[unix-history] / usr.bin / tip / uucplock.c

/*
 * Copyright (c) 1988 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.
 *
 * PATCHES MAGIC                LEVEL   PATCH THAT GOT US HERE
 * --------------------         -----   ----------------------
 * CURRENT PATCH LEVEL:         1       00139
 * --------------------         -----   ----------------------
 *
 * 19 Aug 93	Peter da Silva		Better errors and Taylor UUCP locks
 *
 */

#ifndef lint
static char sccsid[] = "@(#)uucplock.c	5.5 (Berkeley) 6/1/90";
#endif /* not lint */

#include <stdio.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;
{
	extern int errno;
	int fd, pid;
	char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
	off_t lseek();
	char text_pid[81];	/* PDS 93 */
	int len;		/* PDS 93 */

	(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);	/* +PDS 93 */
			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);	/* -PDS 93 */

		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
		 */
	/* +PDS 93 */
		fprintf(stderr, "Stale lock on %s PID=%d... overriding.\n",
			ttyname, pid);
		if (lseek(fd, 0L, 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) {	/* -PDS 93 */
		(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));
}
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) 1988 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	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.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	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
	31	* SUCH DAMAGE.
	32	*
	33	* PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
	34	* -------------------- ----- ----------------------
	35	* CURRENT PATCH LEVEL: 1 00139
	36	* -------------------- ----- ----------------------
	37	*
	38	* 19 Aug 93 Peter da Silva Better errors and Taylor UUCP locks
	39	*
	40	*/
	41
	42	#ifndef lint
	43	static char sccsid[] = "@(#)uucplock.c 5.5 (Berkeley) 6/1/90";
	44	#endif /* not lint */
	45
	46	#include <stdio.h>
	47	#include <sys/types.h>
	48	#include <sys/file.h>
	49	#include <sys/dir.h>
	50	#include <errno.h>
	51	#include "pathnames.h"
	52
	53	/*
	54	* uucp style locking routines
	55	* return: 0 - success
	56	* -1 - failure
	57	*/
	58
	59	uu_lock(ttyname)
	60	char *ttyname;
	61	{
	62	extern int errno;
	63	int fd, pid;
	64	char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
65	off_t lseek();
66	char text_pid[81]; /* PDS 93 */
67	int len; /* PDS 93 */
68
69	(void)sprintf(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); /* +PDS 93 */
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); /* -PDS 93 */
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	/* +PDS 93 */
101	fprintf(stderr, "Stale lock on %s PID=%d... overriding.\n",
102	ttyname, pid);
103	if (lseek(fd, 0L, L_SET) < 0) {
104	perror(tbuf);
105	(void)close(fd);
106	fprintf(stderr, "Can't seek lock file.\n");
107	return(-1);
108	}
109	/* fall out and finish the locking process */
110	}
111	pid = getpid();
112	sprintf(text_pid, "%10d\n", pid);
113	len = strlen(text_pid);
114	if (write(fd, text_pid, len) != len) { /* -PDS 93 */
115	(void)close(fd);
116	(void)unlink(tbuf);
117	perror("lock write");
118	return(-1);
119	}
120	(void)close(fd);
121	return(0);
122	}
123
124	uu_unlock(ttyname)
125	char *ttyname;
126	{
127	char tbuf[sizeof(_PATH_LOCKDIRNAME) + MAXNAMLEN];
128
129	(void)sprintf(tbuf, _PATH_LOCKDIRNAME, ttyname);
130	return(unlink(tbuf));
131	}