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/*
LibRCC - module responsible for application synchronization (write access to
a shared config mainly)
Copyright (C) 2005-2008 Suren A. Chilingaryan <csa@dside.dyndns.org>
This program is free software; you can redistribute it and/or modify it
under the terms of version 2 of the GNU General Public License as published
by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <errno.h>
#include "../config.h"
#ifdef HAVE_SYS_FILE_H
# include <sys/file.h>
#endif /* HAVE_SYS_FILE_H */
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif /* HAVE_SYS_TYPES_H */
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif /* HAVE_SYS_STAT_H */
#include "rcchome.h"
#include "rcclock.h"
static int lockfd = -1;
int rccLock() {
# ifdef HAVE_SYS_FILE_H
int err, i;
int size;
char *stmp;
struct timespec wait = { 0, 10000000 };
if (lockfd>=0) return -1;
size = strlen(rcc_home_dir) + 32;
stmp = (char*)malloc(size*sizeof(char));
if (!stmp) return -1;
sprintf(stmp,"%s/.rcc/", rcc_home_dir);
mkdir(stmp, 00755);
sprintf(stmp,"%s/.rcc/locks/", rcc_home_dir);
mkdir(stmp, 00700);
sprintf(stmp,"%s/.rcc/locks/rcc.lock", rcc_home_dir);
lockfd = open(stmp, O_RDWR|O_CREAT, 0644);
if (lockfd >= 0) {
for (err = -1, i = 0; i < (LIBRCC_LOCK_WAIT/10); i++) {
err = flock(lockfd, LOCK_EX|LOCK_NB);
if ((err)&&(errno == EWOULDBLOCK)) nanosleep(&wait, NULL);
else break;
}
if (err) {
close(lockfd);
// Removing invalid lock
if (i == (LIBRCC_LOCK_WAIT/10)) {
remove(stmp);
lockfd = open(stmp, O_RDWR|O_CREAT, 0644);
if (lockfd >= 0) {
for (err = -1, i = 0; i < (LIBRCC_LOCK_WAIT/10); i++) {
err = flock(lockfd, LOCK_EX|LOCK_NB);
if ((err)&&(errno == EWOULDBLOCK)) nanosleep(&wait, NULL);
else break;
}
if (err) close(lockfd);
else return 0;
}
}
lockfd = -1;
return -1;
}
return 0;
}
return -1;
# else /* HAVE_SYS_FILE_H */
return 0;
# endif /* HAVE_SYS_FILE_H */
}
void rccUnLock() {
#ifdef HAVE_SYS_FILE_H
int size;
char *stmp;
if (lockfd<0) return;
size = strlen(rcc_home_dir) + 32;
stmp = (char*)malloc(size*sizeof(char));
if (!stmp) return;
sprintf(stmp,"%s/.rcc/locks/rcc.lock", rcc_home_dir);
flock(lockfd, LOCK_UN);
close(lockfd);
lockfd = -1;
#endif /* HAVE_SYS_FILE_H */
}
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