84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
/* $Id$
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*
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* isync - IMAP4 to maildir mailbox synchronizer
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* Copyright (C) 2002 Michael R. Elkins <me@mutt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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* this file contains routines to establish a mutex using a `dotlock' file
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*/
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#if TESTING
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#include <stdio.h>
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#endif
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#include "dotlock.h"
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static struct flock lck = { 0, SEEK_SET, 0, 0, 0 };
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int dotlock_lock (const char *path, int *fd)
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{
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*fd = open (path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
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if (*fd == -1)
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return -1;
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lck.l_type = F_WRLCK;
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if (fcntl (*fd, F_SETLK, &lck))
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{
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close (*fd);
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*fd = -1;
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return -1;
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}
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return 0;
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}
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int dotlock_unlock (int *fd)
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{
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int r = 0;
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if (*fd != -1)
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{
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lck.l_type = F_UNLCK;
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if (fcntl (*fd, F_SETLK, &lck))
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r = -1;
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close (*fd);
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*fd = -1;
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}
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return r;
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}
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#if TESTING
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int main (void)
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{
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int fd;
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if (dotlock_lock ("./lock", &fd))
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{
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perror ("dotlock_lock");
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goto done;
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}
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puts ("sleeping for 5 seconds");
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sleep(5);
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if (dotlock_unlock (&fd))
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{
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perror ("dotlock_unlock");
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}
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done:
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exit (0);
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}
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#endif
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