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deb-mbse/lib/nodelock.c

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/*****************************************************************************
*
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* $Id$
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* Purpose ...............: Node locking
*
*****************************************************************************
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* Copyright (C) 1997-2005
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*
* 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
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* Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*****************************************************************************/
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#include "../config.h"
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#include "mbselib.h"
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int nodelock(faddr *addr, pid_t mypid)
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{
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char *fn, *tfn, *p, tmp[16];
FILE *fp;
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pid_t pid;
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int tmppid, sverr, rc;
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time_t ltime, now;
fn = bsyname(addr);
tfn = xstrcpy(fn);
if ((p=strrchr(tfn,'/')))
*++p='\0';
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snprintf(tmp, 16, "aa%d", mypid);
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tfn = xstrcat(tfn, tmp);
mkdirs(tfn, 0770);
if ((fp = fopen(tfn,"w")) == NULL) {
WriteError("$Can't open tmp file for bsy lock (%s) \"%s\"",ascfnode(addr, 0x1f), tfn);
free(tfn);
return 1;
}
fprintf(fp,"%10d\n", mypid);
fclose(fp);
chmod(tfn, 0440);
if (link(tfn, fn) == 0) {
unlink(tfn);
free(tfn);
return 0;
} else {
sverr = errno;
}
if (sverr != EEXIST) {
WriteError("$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("$Could not open existing lock file \"%s\"",fn);
WriteError("Locking %s failed", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
}
/*
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* Lock exists, check owner. If rc <> 1 then the lock may have
* been created by another OS (zero bytes lock).
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*/
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rc = fscanf(fp, "%d", &tmppid);
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pid = tmppid;
fclose(fp);
/*
* If lock is our own lock, then it's ok and we are ready.
*/
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if (mypid == pid) {
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unlink(tfn);
free(tfn);
return 0;
}
/*
* Stale or old lock tests
*/
ltime = file_time(fn);
now = time(NULL);
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if (CFG.ZeroLocks && (rc != 1) && (((unsigned long)now - (unsigned long)ltime) > 21600)) {
Syslog('+', "Found zero byte lock older then 6 hours for %s, unlink", ascfnode(addr,0x1f));
unlink(fn);
} else if (CFG.ZeroLocks && (rc != 1)) {
Syslog('+', "Node %s is locked from another OS", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
} else if (kill(pid, 0) && (errno == ESRCH)) {
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Syslog('+', "Found stale bsy file for %s, unlink", ascfnode(addr,0x1f));
unlink(fn);
} else if (((unsigned long)now - (unsigned long)ltime) > 21600) {
Syslog('+', "Found lock older then 6 hours for %s, unlink", ascfnode(addr,0x1f));
unlink(fn);
} else {
Syslog('+', "Node %s is locked by pid %d", ascfnode(addr, 0x1f), pid);
unlink(tfn);
free(tfn);
return 1;
}
if (link(tfn,fn) == 0) {
unlink(tfn);
free(tfn);
return 0;
} else {
WriteError("$Could not link \"%s\" to \"%s\"",tfn,fn);
WriteError("Locking %s failed", ascfnode(addr, 0x1f));
unlink(tfn);
free(tfn);
return 1;
}
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}
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int nodeulock(faddr *addr, pid_t mypid)
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{
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char *fn;
FILE *fp;
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pid_t pid;
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int tmppid = 0, rc;
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fn = bsyname(addr);
if ((fp = fopen(fn, "r")) == NULL) {
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Syslog('+', "Unlock %s failed, not locked", ascfnode(addr, 0x1f));
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return 1;
}
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rc = fscanf(fp, "%d", &tmppid);
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pid = tmppid;
fclose(fp);
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if (CFG.ZeroLocks && (rc != 1)) {
/*
* Zero byte lock from another OS, leave alone.
*/
return 0;
} else if (pid == mypid) {
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unlink(fn);
return 0;
} else {
WriteError("Unlock (%s) file failed for process %u, we are %u", ascfnode(addr, 0x1f), pid,mypid);
return 1;
}
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}