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deb-mbse/lib/nodelock.c

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2001-08-17 05:46:24 +00:00
/*****************************************************************************
*
* File ..................: nodelock.c
* Purpose ...............: Node locking
* Last modification date : 18-Mar-2000
*
*****************************************************************************
* Copyright (C) 1997-2000
*
* 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, 675 Mass Ave, Cambridge, MA 02139, USA.
*****************************************************************************/
#include "libs.h"
#include "structs.h"
#include "clcomm.h"
#include "common.h"
int nodelock(faddr *addr)
{
char *fn,*tfn,*p;
char tmp[16];
FILE *fp;
pid_t pid,mypid;
int tmppid,sverr;
fn = bsyname(addr);
tfn = xstrcpy(fn);
if ((p=strrchr(tfn,'/')))
*++p='\0';
mypid = getpid();
sprintf(tmp, "aa%d", mypid);
tfn = xstrcat(tfn, tmp);
mkdirs(tfn);
if ((fp = fopen(tfn,"w")) == NULL) {
WriteError("$Can't open tmp file for bsy lock (%s) \"%s\"",ascfnode(addr, 0x1f), tfn);
free(tfn);
return 1;
}
fprintf(fp,"%10d\n", mypid);
fclose(fp);
chmod(tfn, 0444);
if (link(tfn, fn) == 0) {
unlink(tfn);
free(tfn);
return 0;
} else {
sverr=errno;
}
if (sverr != EEXIST) {
WriteError("$Could not link \"%s\" to \"%s\"",tfn,fn);
WriteError("Locking %s failed", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
}
if ((fp=fopen(fn,"r")) == NULL) {
WriteError("$Could not open existing lock file \"%s\"",fn);
WriteError("Locking %s failed", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
}
/*
* Lock exists, check owner
*/
fscanf(fp, "%d", &tmppid);
pid = tmppid;
fclose(fp);
/*
* If lock is our own lock, then it's ok and we are ready.
*/
if (getpid() == pid) {
unlink(tfn);
free(tfn);
return 0;
}
if (kill(pid, 0) && (errno == ESRCH)) {
Syslog('+', "Found stale bsy file for %s, unlink", ascfnode(addr,0x1f));
unlink(fn);
} else {
Syslog('+', "Node %s is locked by pid %d", ascfnode(addr, 0x1f), pid);
unlink(tfn);
free(tfn);
return 1;
}
if (link(tfn,fn) == 0) {
unlink(tfn);
free(tfn);
return 0;
} else {
WriteError("$Could not link \"%s\" to \"%s\"",tfn,fn);
WriteError("Locking %s failed", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
}
}
int nodeulock(faddr *addr)
{
char *fn;
FILE *fp;
pid_t pid,mypid;
int tmppid;
fn = bsyname(addr);
if ((fp = fopen(fn, "r")) == NULL) {
WriteError("$Can't open lock file (%s) \"%s\"", ascfnode(addr, 0x1f), fn);
return 1;
}
fscanf(fp, "%d", &tmppid);
pid = tmppid;
fclose(fp);
mypid = getpid();
if (pid == mypid) {
unlink(fn);
return 0;
} else {
WriteError("Unlock (%s) file failed for process %u, we are %u", ascfnode(addr, 0x1f), pid,mypid);
return 1;
}
}