1995-09-14 22:01:06 +00:00
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/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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1997-04-02 04:24:39 +00:00
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*
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1997-08-05 12:58:02 +00:00
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* $Id: uucplock.c,v 1.6 1997/05/12 10:36:14 brian Exp $
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1997-04-02 04:24:39 +00:00
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*
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1995-09-14 22:01:06 +00:00
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*/
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#ifndef lint
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1996-03-04 10:35:45 +00:00
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static const char sccsid[] = "@(#)uucplock.c 8.1 (Berkeley) 6/6/93";
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1995-09-14 22:01:06 +00:00
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#endif /* not lint */
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#include <sys/types.h>
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#include <sys/file.h>
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1996-09-24 08:08:11 +00:00
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#include <dirent.h>
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1995-09-14 22:01:06 +00:00
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#include <errno.h>
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1995-09-19 03:37:07 +00:00
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#include <unistd.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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1995-09-20 13:10:50 +00:00
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#include <paths.h>
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1997-03-31 22:51:00 +00:00
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#include <string.h>
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#include "libutil.h"
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1995-09-14 22:01:06 +00:00
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1995-09-20 13:10:50 +00:00
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#define LOCKFMT "LCK..%s"
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1995-09-14 22:01:06 +00:00
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/* Forward declarations */
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1995-09-19 03:37:07 +00:00
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static int put_pid (int fd, pid_t pid);
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1997-03-31 22:51:00 +00:00
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static pid_t get_pid (int fd,int *err);
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1995-09-14 22:01:06 +00:00
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/*
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* uucp style locking routines
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* return: 0 - success
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* -1 - failure
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*/
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1997-05-12 10:36:14 +00:00
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int uu_lock (const char *ttyname)
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1995-09-14 22:01:06 +00:00
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{
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1995-09-19 03:37:07 +00:00
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int fd;
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pid_t pid;
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1996-03-04 10:35:45 +00:00
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char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
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1997-03-31 22:51:00 +00:00
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int err;
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1995-09-14 22:01:06 +00:00
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1997-04-02 03:38:29 +00:00
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(void)snprintf(tbuf, sizeof(tbuf), _PATH_UUCPLOCK LOCKFMT, ttyname);
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1997-08-05 12:58:02 +00:00
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fd = open(tbuf, O_RDWR|O_CREAT|O_EXCL|O_EXLOCK, 0660);
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1995-09-14 22:01:06 +00:00
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if (fd < 0) {
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/*
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* file is already locked
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* check to see if the process holding the lock still exists
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*/
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1997-08-05 12:58:02 +00:00
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fd = open(tbuf, O_RDWR|O_SHLOCK);
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1997-03-31 22:51:00 +00:00
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if (fd < 0)
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return UU_LOCK_OPEN_ERR;
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if ((pid = get_pid (fd, &err)) == -1) {
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1995-09-19 03:37:07 +00:00
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(void)close(fd);
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1997-03-31 22:51:00 +00:00
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errno = err;
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return UU_LOCK_READ_ERR;
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1995-09-14 22:01:06 +00:00
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}
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if (kill(pid, 0) == 0 || errno != ESRCH) {
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(void)close(fd); /* process is still running */
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1997-03-31 22:51:00 +00:00
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return UU_LOCK_INUSE;
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1995-09-14 22:01:06 +00:00
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}
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/*
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* The process that locked the file isn't running, so
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* we'll lock it ourselves
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*/
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1996-03-04 10:35:45 +00:00
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if (lseek(fd, (off_t) 0, L_SET) < 0) {
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1997-03-31 22:51:00 +00:00
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err = errno;
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1995-09-19 03:37:07 +00:00
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(void)close(fd);
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1997-03-31 22:51:00 +00:00
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errno = err;
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return UU_LOCK_SEEK_ERR;
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1995-09-14 22:01:06 +00:00
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}
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1997-08-05 12:58:02 +00:00
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if (flock(fd, LOCK_EX|LOCK_NB) < 0) {
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(void)close(fd);
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return UU_LOCK_INUSE;
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}
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1995-09-14 22:01:06 +00:00
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/* fall out and finish the locking process */
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}
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pid = getpid();
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if (!put_pid (fd, pid)) {
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1997-03-31 22:51:00 +00:00
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err = errno;
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1995-09-14 22:01:06 +00:00
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(void)unlink(tbuf);
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1997-08-05 12:58:02 +00:00
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(void)close(fd);
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1997-03-31 22:51:00 +00:00
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errno = err;
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return UU_LOCK_WRITE_ERR;
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1995-09-14 22:01:06 +00:00
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}
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(void)close(fd);
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1997-03-31 22:51:00 +00:00
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return UU_LOCK_OK;
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1995-09-14 22:01:06 +00:00
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}
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1997-05-12 10:36:14 +00:00
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int uu_unlock (const char *ttyname)
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1995-09-14 22:01:06 +00:00
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{
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1996-03-04 10:35:45 +00:00
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char tbuf[sizeof(_PATH_UUCPLOCK) + MAXNAMLEN];
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1995-09-14 22:01:06 +00:00
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1997-04-02 03:38:29 +00:00
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(void)snprintf(tbuf, sizeof(tbuf), _PATH_UUCPLOCK LOCKFMT, ttyname);
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1997-03-31 22:51:00 +00:00
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return unlink(tbuf);
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}
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1997-05-12 10:36:14 +00:00
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const char *uu_lockerr (int uu_lockresult)
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1997-03-31 22:51:00 +00:00
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{
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1997-04-02 04:24:39 +00:00
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static char errbuf[128];
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1997-04-02 03:53:49 +00:00
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char *fmt;
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1997-03-31 22:51:00 +00:00
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switch (uu_lockresult) {
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case UU_LOCK_INUSE:
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1997-04-02 03:38:29 +00:00
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return "device in use";
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1997-03-31 22:51:00 +00:00
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case UU_LOCK_OK:
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1997-04-02 03:38:29 +00:00
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return "";
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1997-03-31 22:51:00 +00:00
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case UU_LOCK_OPEN_ERR:
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1997-04-02 03:53:49 +00:00
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fmt = "open error: %s";
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1997-03-31 22:51:00 +00:00
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break;
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case UU_LOCK_READ_ERR:
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1997-04-02 03:53:49 +00:00
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fmt = "read error: %s";
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1997-03-31 22:51:00 +00:00
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break;
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case UU_LOCK_SEEK_ERR:
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1997-04-02 03:53:49 +00:00
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fmt = "seek error: %s";
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1997-03-31 22:51:00 +00:00
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break;
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case UU_LOCK_WRITE_ERR:
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1997-04-02 03:53:49 +00:00
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fmt = "write error: %s";
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1997-03-31 22:51:00 +00:00
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break;
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default:
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1997-04-02 03:53:49 +00:00
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fmt = "undefined error: %s";
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1997-03-31 22:51:00 +00:00
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break;
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}
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1997-04-02 03:53:49 +00:00
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(void)snprintf(errbuf, sizeof(errbuf), fmt, strerror(errno));
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1997-03-31 22:51:00 +00:00
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return errbuf;
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1995-09-14 22:01:06 +00:00
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}
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1995-09-19 03:37:07 +00:00
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static int put_pid (int fd, pid_t pid)
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1995-09-14 22:01:06 +00:00
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{
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1996-03-04 10:35:45 +00:00
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char buf[32];
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1995-09-14 22:01:06 +00:00
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int len;
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1996-04-13 15:47:43 +00:00
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len = sprintf (buf, "%10d\n", pid);
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1996-03-04 10:35:45 +00:00
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return write (fd, buf, len) == len;
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1995-09-14 22:01:06 +00:00
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}
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1997-03-31 22:51:00 +00:00
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static pid_t get_pid (int fd,int *err)
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1995-09-14 22:01:06 +00:00
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{
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1995-09-19 03:37:07 +00:00
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int bytes_read;
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1996-03-04 10:35:45 +00:00
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char buf[32];
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1995-09-19 03:37:07 +00:00
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pid_t pid;
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1995-09-14 22:01:06 +00:00
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1996-03-04 10:35:45 +00:00
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bytes_read = read (fd, buf, sizeof (buf) - 1);
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if (bytes_read > 0) {
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buf[bytes_read] = '\0';
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pid = strtol (buf, (char **) NULL, 10);
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1997-03-31 22:51:00 +00:00
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} else {
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1996-03-04 10:35:45 +00:00
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pid = -1;
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1997-03-31 22:51:00 +00:00
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*err = bytes_read ? errno : EINVAL;
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}
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1996-03-04 10:35:45 +00:00
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return pid;
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1995-09-14 22:01:06 +00:00
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}
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/* end of uucplock.c */
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