daemon.c

qADSL is an auto-login & keep-alive daemon for Internet connections. It was created to automate the

/* daemon.c - Holds the auto-login daemon and its code.
 *
 * Copyright (c) 2001 Jakob "kuba" Stasilowicz <[e-mail]>
 * Copyright (c) 2003 Joachim Nilsson <[e-mail]>
 *
 * qADSL 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.
 *
 * qADSL 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>

#include "conf.h"
#include "lock.h"
#include "log.h"
#include "http.h"


/**
 * daemonize: Fork off the deamon process and detach from session context.
 *
 * Disassociate from process group and controlling terminal forking off
 * the daemon process. The function returns a fork() pid value as result.
 *
 * Returns: A pid value. Negative value is error, positive is child pid
 *          zero indicates that the child is executing.
 */

int
daemonize (void)
{
  int fd;
  pid_t pid;

  /* Fork off daemon process */
  pid = fork ();
  if (0 != pid)
    {
      return pid;
    }

  /* or setsid() to lose control terminal and change process group */
  setpgrp ();

  /* Prevent reacquisition of a controlling terminal */
  pid = fork ();
  if (0 != pid)
    {
      /* Reap the child and let the grandson live on. */
      exit (EXIT_SUCCESS);
    }

  /* If parent is NOT init. */
  if (1 != getppid ())
    {
#ifdef SIGTTOU
      /* Ignore if background tty attempts write. */
      signal (SIGTTOU, SIG_IGN);
#endif
#ifdef SIGTTIN
      /* Ignore if background tty attempts read. */
      signal (SIGTTIN, SIG_IGN);
#endif

#ifdef SIGTSTP
      /* Ignore any keyboard generated stop signal signals. */
      signal (SIGTSTP, SIG_IGN);
#endif
      /* Become session leader and group process leader
       * with no controlling terminal 
       */
      setsid ();
    }

  /* Close all open files */
  for (fd = 0; fd < sysconf(_SC_OPEN_MAX); fd++)  /* XXX - Add configure check */
    {
      close (fd);
    }

  /* Move current directory off mounted file system */
  chdir ("/");
  /* Clear any inherited file mode creation mask */
  umask (0);

  return pid;
}


static void
daemon_sighandler (int signal)
{
  write_log ("%s[%d]: Got signal(%d), quiting!\n", 
             PACKAGE_NAME, getpid (), signal);

  exit (0);
}



/**
 * autologin_daemon - This is what keeps us going
 * 
 * This thread function is the one responsible for keeping the
 * connection open. This function is called when a properly
 * daemonized thread is started.
 */

void
daemon_thread (config_data_t *config)
{
  int result;
  unsigned int timeout = 60 * config->daemon_delay;
  pid_t mypid = getpid ();

  write_log ("qADSL daemon started, pid: %d\n", mypid);

  (void) signal (SIGTERM, daemon_sighandler);
  result = lock_create (&config->pid_file, mypid);
  if (result)
    {
      /* If we cannot create the logfile we do not allow the
       * daemon to start since there is no way (other than ps)
       * to communicate the PID to the outside world.
       */
      write_log ("Cannot write PID(%d) to file, %s - %s\n"
		 "Aborting daemon - cannot communicate PID to outside world.\n",
                 (int)mypid, config->pid_file, strerror (errno));
      /* Bye bye */
      return;
    }

  while (1)
    {
      /* Close all connections before going to sleep. */
      close (config->sockfd);

      /* Now, sleep before we reconnect and check status. */
      sleep (timeout);

      config->sockfd = open_server (config->login_server, config->server_port, 0);
      if (-1 == config->sockfd)
        {
          write_log ("Failed to contact server.");
          continue;
        }
      
      /* The "ping" daemon only reads /sd/init */
      result = pre_login (config, 0);
      if (result)
        {
          write_log ("%s: Failed to bring up login page.\n", PACKAGE_NAME);
          continue;
        }
      /* Test if we're logged in already. */
      if (strstr (config->get_msg, config->logged_in_string))
        {
          config->logged_in = 1;
        }
      
      /* The login daemon also tries to login. */
      if (config->daemon_type && !(config->logged_in))
        {
          log_login (config, 0);
        }
    }
}


/**
 * daemon_kill - Terminates the login daemon.
 * @pid: Process ID to kill.
 *
 * This function sends SIGTERM to gracefully let the
 * login daemon process .. exit.
 *
 * Returns: The result of kill().
 */

int
daemon_kill (pid_t pid)
{
  return kill (pid, SIGTERM);
}