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deb-mbse/mbfido/dirlock.c
2004-02-21 17:22:00 +00:00

151 lines
3.7 KiB
C

/*****************************************************************************
*
* $Id$
* Purpose ...............: Lock mbfido processing.
*
*****************************************************************************
* Copyright (C) 1997-2004
*
* 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 "flock.h"
#include "dirlock.h"
#define TMPNAME "TMP."
#define LCKNAME "LOCKFILE"
/*
* Put a lock on a directory.
*/
int lockdir(char *directory)
{
char *Tmpfile, *lockfile;
FILE *fp;
pid_t oldpid;
Tmpfile = calloc(PATH_MAX, sizeof(char));
lockfile = calloc(PATH_MAX, sizeof(char));
sprintf(Tmpfile, "%s/", directory);
strcpy(lockfile, Tmpfile);
sprintf(Tmpfile + strlen(Tmpfile), "%s%u", TMPNAME, getpid());
sprintf(lockfile + strlen(lockfile), "%s", LCKNAME);
if ((fp = fopen(Tmpfile, "w")) == NULL) {
WriteError("$Can't create lockfile \"%s\"", Tmpfile);
free(Tmpfile);
free(lockfile);
return FALSE;
}
fprintf(fp, "%10u\n", getpid());
fclose(fp);
while (TRUE) {
if (link(Tmpfile, lockfile) == 0) {
unlink(Tmpfile);
free(Tmpfile);
free(lockfile);
return TRUE;
}
if ((fp = fopen(lockfile, "r")) == NULL) {
WriteError("$Can't open lockfile \"%s\"", Tmpfile);
unlink(Tmpfile);
free(Tmpfile);
free(lockfile);
return FALSE;
}
if (fscanf(fp, "%u", &oldpid) != 1) {
WriteError("$Can't read old pid from \"%s\"", Tmpfile);
fclose(fp);
unlink(Tmpfile);
free(Tmpfile);
free(lockfile);
return FALSE;
}
fclose(fp);
if (kill(oldpid,0) == -1) {
if (errno == ESRCH) {
Syslog('+', "Stale lock found for pid %u", oldpid);
unlink(lockfile);
/* no return, try lock again */
} else {
WriteError("$Kill for %u failed",oldpid);
unlink(Tmpfile);
free(Tmpfile);
free(lockfile);
return FALSE;
}
} else {
Syslog('+', "mbfido already running, pid=%u", oldpid);
unlink(Tmpfile);
free(Tmpfile);
free(lockfile);
return FALSE;
}
}
}
/*
* Unlock directory, make extra check to see if it is our own lock.
*/
void ulockdir(char *directory)
{
char *lockfile;
FILE *fp;
pid_t oldpid;
lockfile = calloc(PATH_MAX, sizeof(char));
sprintf(lockfile, "%s/", directory);
sprintf(lockfile + strlen(lockfile), "%s", LCKNAME);
if ((fp = fopen(lockfile, "r")) == NULL) {
/*
* No lockfile found, so not removed.
*/
free(lockfile);
return;
}
if (fscanf(fp, "%u", &oldpid) != 1) {
WriteError("$Can't read old pid from \"%s\"", lockfile);
} else {
if (getpid() != oldpid) {
WriteError("Attempt to remove lock %s of pid %d", lockfile, oldpid);
} else {
/*
* Only remove our own lock.
*/
unlink(lockfile);
}
}
fclose(fp);
free(lockfile);
}