deb-mbse/mbfido/ulock.c

/*****************************************************************************
 *
 * $Id$
 * Purpose ...............: Lock mbfido processing.
 *
 *****************************************************************************
 * Copyright (C) 1997-2002
 *   
 * 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 "../config.h"
#include "../lib/libs.h"
#include "../lib/memwatch.h"
#include "../lib/structs.h"
#include "../lib/users.h"
#include "../lib/records.h"
#include "../lib/common.h"
#include "../lib/clcomm.h"
#include "flock.h"
#include "ulock.h"

#define UNPACK_FACTOR 300
#define TOSS_FACTOR 120
#define TMPNAME "TMP."
#define LCKNAME "LOCKFILE"


static char lockfile[81];

extern int do_quiet;
static int is_locked = FALSE;


/*
 *  Put a lock on this program.
 */
int lockunpack(void)
{
	char	Tmpfile[81];
	FILE	*fp;
	pid_t	oldpid;

	sprintf(Tmpfile, "%s/", CFG.inbound);
	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);
		return 1;
	}
	fprintf(fp, "%10u\n", getpid());
	fclose(fp);

	while (1) {
		if (link(Tmpfile, lockfile) == 0) {
			unlink(Tmpfile);
			is_locked = TRUE;
			return 0;
		}
		if ((fp = fopen(lockfile, "r")) == NULL) {
			WriteError("$Can't open lockfile \"%s\"", Tmpfile);
			unlink(Tmpfile);
			return 1;
		}
		if (fscanf(fp, "%u", &oldpid) != 1) {
			WriteError("$Can't read old pid from \"%s\"", Tmpfile);
			fclose(fp);
			unlink(Tmpfile);
			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 {
				WriteError("$Kill for %u failed",oldpid);
				unlink(Tmpfile);
				return 1;
			}
		} else {
			Syslog('+', "mbfido already running, pid=%u", oldpid);
			unlink(Tmpfile);
			return 1;
		}
	}
}



void ulockunpack(void)
{
	if (is_locked && lockfile)
		(void)unlink(lockfile);
}



int checkspace(char *dir, char *fn, int factor)
{
	struct stat	st;
	struct statfs	sfs;

	if ((stat(fn,&st) != 0) || (statfs(dir,&sfs) != 0)) {
		WriteError("Cannot stat \"%s\" or statfs \"%s\", assume enough space", fn, dir);
		return 1;
	}

	if ((((st.st_size / sfs.f_bsize +1) * factor) / 100L) > sfs.f_bfree) {
		Syslog('!', "Only %lu %lu-byte blocks left on device where %s is located",
			sfs.f_bfree,sfs.f_bsize,dir);
		return 0;
	}
	return 1;
}



/*
 * Unpack archive
 */
int unpack(char *fn)
{
    char	newname[16];
    char	*cmd = NULL, *unarc;
    int		rc = 0, ld;

    if (!do_quiet) {
	colour(11, 0);
	printf("Unpacking file %s\n", fn);
    }

    if ((unarc = unpacker(fn)) == NULL) 
	return 1;

    if (!getarchiver(unarc))
	return 1;

    cmd = xstrcpy(archiver.munarc);

    if ((cmd == NULL) || (cmd == ""))
	return -1;

    if ((ld = f_lock(fn)) == -1) {
	free(cmd);
	return 1;
    }

    if ((rc = execute(cmd,fn,(char *)NULL,(char*)"/dev/null",(char*)"/dev/null",(char*)"/dev/null")) == 0) {
	sync();
	unlink(fn);
    } else {
	sync();
	sleep(1);
	Syslog('!', "Warning: unpack %s failed, trying again after sync()", fn);
	if ((rc = execute(cmd,fn,(char *)NULL,(char*)"/dev/null",(char*)"/dev/null",(char*)"/dev/null")) == 0) {
	    sync();
	    unlink(fn);
	} else {
	    sync();
	    strncpy(newname,fn,sizeof(newname)-1);
	    strcpy(newname+8,".bad");
	    rename(fn,newname);
	}
    }

    free(cmd);
    funlock(ld); 
    return rc;
}