lockfile.c

Go to the documentation of this file.

/*
 *  $Id: lockfile.c,v 1.5 2005/12/15 20:19:08 ghost666 Exp $
 *
 *  rssbgr - RSS backgroud reader
 *  Copyright (C) 2005 Piotr 'GhosT' Wydrych
 *
 *  This program 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 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "lockfile.h"

void create_lockfile(void/*char *directory, char *lockfile*/)
{
 int lockfile_d;
 unsigned int other_pid;
 FILE *lockfile_s;
 struct stat stats;

 if (mkdir(directory, S_IRWXU) == -1)
 {
  if ((errno != EEXIST) || ((stat(directory, &stats) == 0) && ((stats.st_mode & S_IFMT) != S_IFDIR)))
   DIE("Cannot create directory for storing settings. Program will exit.")
  chmod(directory, S_IRWXU);
 }
 if ((lockfile_d = open(lockfile, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR)) == -1)
 {
  if ((errno==EEXIST) && (stat(lockfile, &stats) == 0) && ((stats.st_mode & S_IFMT) == S_IFREG) && ((lockfile_s = fopen(lockfile, "r")) != NULL) && (fscanf(lockfile_s, "%u", &other_pid) == 1))
  {
    fprintf(stdout, "Probably another copy of RSS Background Reader runs with PID %u. Program will exit.\nIf you are sure, that RSSBGR is not running, please delete the file %s\n", other_pid, lockfile);
    fclose(lockfile_s);
    _exit(1);
  }
  else
   DIE("Cannot create lockfile")
 }
 /*close(lockfile_d);
 lockfile_s=fopen(lockfile, "w");
 fprintf(lockfile_s, "%u", (int) getpid());
 fclose(lockfile_s);*/
 lockfile_s = fdopen(lockfile_d, "w");
 fprintf(lockfile_s, "%u", (int) getpid());
 fflush(lockfile_s);
 close(lockfile_d);
}

/* --------- */

void check_lockfile(void/*char *lockfile*/)
{
 time_t mtime, ctime;
 struct stat stats;
 
 if (stat(lockfile, &stats) == -1) return;
 mtime = stats.st_mtime;
 ctime = stats.st_ctime; 
 
 while(1)
 {
  sleep(CHECK_LOCKFILE_FREQUENCY);
  if ((stat(lockfile, &stats) == -1) || (stats.st_mtime != mtime) || (stats.st_ctime != ctime))
   return;
 }
}

---