pid_output (const char *path)
{
  int tmp;
  int fd;
  pid_t pid;
  char buf[16];
  struct flock lock;
  mode_t oldumask;

  pid = getpid ();

  oldumask = umask(0777 & ~LOGFILE_MASK);
  fd = open (path, O_RDWR | O_CREAT, LOGFILE_MASK);          
  if (fd < 0)
    {
      zlog_err("Can't create pid lock file %s (%s), exiting",
               path, safe_strerror(errno));
      umask(oldumask);
      exit(1);
    }              
  else
    {
      size_t pidsize;

      umask(oldumask);
      memset (&lock, 0, sizeof(lock));

      lock.l_type = F_WRLCK;
      lock.l_whence = SEEK_SET;

      if (fcntl(fd, F_SETLK, &lock) < 0)
        {
          zlog_err("Could not lock pid_file %s, exiting", path);
          exit(1);
        }         

      sprintf (buf, "%d\n", (int) pid);
      pidsize = strlen(buf);
      if ((tmp = write (fd, buf, pidsize)) != (int)pidsize)
        zlog_err("Could not write pid %d to pid_file %s, rc was %d: %s",
                 (int)pid,path,tmp,safe_strerror(errno));               
      else if (ftruncate(fd, pidsize) < 0)           
        zlog_err("Could not truncate pid_file %s to %u bytes: %s",
                 path,(u_int)pidsize,safe_strerror(errno));
    }             
  return pid;
}