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deb-mbse/mbmon/proglock.c
2015-11-05 18:49:27 -05:00

141 lines
3.5 KiB
C

/*****************************************************************************
*
* $Id: proglock.c,v 1.6 2005/08/28 17:08:04 mbse Exp $
* Purpose ...............: Program Locking
*
*****************************************************************************
* Copyright (C) 1997-2005
*
* Michiel Broek FIDO: 2:280/2802
* Beekmansbos 10
* 1971 BV IJmuiden
* the Netherlands
*
* This file is part of MBSE BBS.
*
* This BBS is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* MBSE BBS 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 MBSE BBS; see the file COPYING. If not, write to the Free
* Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*****************************************************************************/
#include "../config.h"
#include "../lib/mbselib.h"
#include "proglock.h"
/*
* Put a lock on a program.
*/
int lockprogram(char *progname)
{
char *tempfile, *lockfile;
FILE *fp;
pid_t oldpid;
tempfile = calloc(PATH_MAX, sizeof(char));
lockfile = calloc(PATH_MAX, sizeof(char));
snprintf(tempfile, PATH_MAX, "%s/var/run/%s.tmp", getenv("MBSE_ROOT"), progname);
snprintf(lockfile, PATH_MAX, "%s/var/run/%s", getenv("MBSE_ROOT"), progname);
if ((fp = fopen(tempfile, "w")) == NULL) {
Syslog('?', "$Can't create lockfile \"%s\"", tempfile);
free(tempfile);
free(lockfile);
return 1;
}
fprintf(fp, "%10u\n", getpid());
fclose(fp);
while (TRUE) {
if (link(tempfile, lockfile) == 0) {
unlink(tempfile);
free(tempfile);
free(lockfile);
return 0;
}
if ((fp = fopen(lockfile, "r")) == NULL) {
Syslog('?', "$Can't open lockfile \"%s\"", lockfile);
unlink(tempfile);
free(tempfile);
free(lockfile);
return 1;
}
if (fscanf(fp, "%u", &oldpid) != 1) {
Syslog('?', "$Can't read old pid from \"%s\"", tempfile);
fclose(fp);
unlink(tempfile);
free(tempfile);
free(lockfile);
return 1;
}
fclose(fp);
if (kill(oldpid,0) == -1) {
if (errno == ESRCH) {
Syslog('+', "Stale lock found for pid %u", oldpid);
unlink(lockfile);
/* no return, try lock again */
} else {
Syslog('?', "$Kill for %u failed", oldpid);
unlink(tempfile);
free(tempfile);
free(lockfile);
return 1;
}
} else {
Syslog('+', "%s already running, pid=%u", progname, oldpid);
unlink(tempfile);
free(tempfile);
free(lockfile);
return 1;
}
}
}
void ulockprogram(char *progname)
{
char *lockfile;
pid_t oldpid;
FILE *fp;
lockfile = calloc(PATH_MAX, sizeof(char));
snprintf(lockfile, PATH_MAX, "%s/var/run/%s", getenv("MBSE_ROOT"), progname);
if ((fp = fopen(lockfile, "r")) == NULL) {
Syslog('?', "$Can't open lockfile \"%s\"", lockfile);
free(lockfile);
return;
}
if (fscanf(fp, "%u", &oldpid) != 1) {
Syslog('?', "$Can't read old pid from \"%s\"", lockfile);
fclose(fp);
unlink(lockfile);
free(lockfile);
return;
}
fclose(fp);
if (oldpid == getpid()) {
(void)unlink(lockfile);
} else {
Syslog('?', "Lockfile owned by pid %d, not removed", oldpid);
}
free(lockfile);
}