Merge changes from CUPS 1.6svn-r10310.

[thirdparty/cups.git] / scheduler / main.c

/*
 * "$Id: main.c 7925 2008-09-10 17:47:26Z mike $"
 *
 *   Main loop for the CUPS scheduler.
 *
 *   Copyright 2007-2012 by Apple Inc.
 *   Copyright 1997-2007 by Easy Software Products, all rights reserved.
 *
 *   These coded instructions, statements, and computer programs are the
 *   property of Apple Inc. and are protected by Federal copyright
 *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
 *   "LICENSE" which should have been included with this file.  If this
 *   file is missing or damaged, see the license at "http://www.cups.org/".
 *
 * Contents:
 *
 *   main()                - Main entry for the CUPS scheduler.
 *   cupsdAddString()      - Copy and add a string to an array.
 *   cupsdCheckProcess()   - Tell the main loop to check for dead children.
 *   cupsdClearString()    - Clear a string.
 *   cupsdFreeStrings()    - Free an array of strings.
 *   cupsdHoldSignals()    - Hold child and termination signals.
 *   cupsdReleaseSignals() - Release signals for delivery.
 *   cupsdSetString()      - Set a string value.
 *   cupsdSetStringf()     - Set a formatted string value.
 *   launchd_checkin()     - Check-in with launchd and collect the listening
 *                           fds.
 *   launchd_checkout()    - Update the launchd KeepAlive file as needed.
 *   parent_handler()      - Catch USR1/CHLD signals...
 *   process_children()    - Process all dead children...
 *   select_timeout()      - Calculate the select timeout value.
 *   sigchld_handler()     - Handle 'child' signals from old processes.
 *   sighup_handler()      - Handle 'hangup' signals to reconfigure the
 *                           scheduler.
 *   sigterm_handler()     - Handle 'terminate' signals that stop the scheduler.
 *   usage()               - Show scheduler usage.
 */

/*
 * Include necessary headers...
 */

#define _MAIN_C_
#include "cupsd.h"
#include <sys/resource.h>
#include <syslog.h>
#include <grp.h>

#ifdef HAVE_LAUNCH_H
#  include <launch.h>
#  include <libgen.h>
#  define CUPS_KEEPALIVE CUPS_CACHEDIR "/org.cups.cupsd"
                                        /* Name of the launchd KeepAlive file */
#  ifndef LAUNCH_JOBKEY_KEEPALIVE
#    define LAUNCH_JOBKEY_KEEPALIVE "KeepAlive"
#  endif /* !LAUNCH_JOBKEY_KEEPALIVE */
#  ifndef LAUNCH_JOBKEY_PATHSTATE
#    define LAUNCH_JOBKEY_PATHSTATE "PathState"
#  endif /* !LAUNCH_JOBKEY_PATHSTATE */
#  ifndef LAUNCH_JOBKEY_SERVICEIPC
#    define LAUNCH_JOBKEY_SERVICEIPC "ServiceIPC"
#  endif /* !LAUNCH_JOBKEY_SERVICEIPC */
#endif /* HAVE_LAUNCH_H */

#if defined(HAVE_MALLOC_H) && defined(HAVE_MALLINFO)
#  include <malloc.h>
#endif /* HAVE_MALLOC_H && HAVE_MALLINFO */
#ifdef HAVE_NOTIFY_H
#  include <notify.h>
#endif /* HAVE_NOTIFY_H */


/*
 * Local functions...
 */

#ifdef HAVE_LAUNCHD
static void             launchd_checkin(void);
static void             launchd_checkout(void);
#endif /* HAVE_LAUNCHD */
static void             parent_handler(int sig);
static void             process_children(void);
static void             sigchld_handler(int sig);
static void             sighup_handler(int sig);
static void             sigterm_handler(int sig);
static long             select_timeout(int fds);
static void             usage(int status) __attribute__((noreturn));


/*
 * Local globals...
 */

static int              parent_signal = 0;
                                        /* Set to signal number from child */
static int              holdcount = 0;  /* Number of times "hold" was called */
#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
static sigset_t         holdmask;       /* Old POSIX signal mask */
#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
static int              dead_children = 0;
                                        /* Dead children? */
static int              stop_scheduler = 0;
                                        /* Should the scheduler stop? */


/*
 * 'main()' - Main entry for the CUPS scheduler.
 */

int                                     /* O - Exit status */
main(int  argc,                         /* I - Number of command-line args */
     char *argv[])                      /* I - Command-line arguments */
{
  int                   i;              /* Looping var */
  char                  *opt;           /* Option character */
  int                   fg;             /* Run in the foreground */
  int                   fds;            /* Number of ready descriptors */
  cupsd_client_t        *con;           /* Current client */
  cupsd_job_t           *job;           /* Current job */
  cupsd_listener_t      *lis;           /* Current listener */
  time_t                current_time,   /* Current time */
                        activity,       /* Client activity timer */
                        senddoc_time,   /* Send-Document time */
                        expire_time,    /* Subscription expire time */
                        report_time,    /* Malloc/client/job report time */
                        event_time;     /* Last event notification time */
  long                  timeout;        /* Timeout for cupsdDoSelect() */
  struct rlimit         limit;          /* Runtime limit */
#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
  struct sigaction      action;         /* Actions for POSIX signals */
#endif /* HAVE_SIGACTION && !HAVE_SIGSET */
#ifdef __sgi
  cups_file_t           *fp;            /* Fake lpsched lock file */
  struct stat           statbuf;        /* Needed for checking lpsched FIFO */
#endif /* __sgi */
  int                   run_as_child = 0;
                                        /* Needed for background fork/exec */
#ifdef __APPLE__
  int                   use_sysman = !getuid();
                                        /* Use system management functions? */
#else
  time_t                netif_time = 0; /* Time since last network update */
#endif /* __APPLE__ */
#if HAVE_LAUNCHD
  int                   launchd_idle_exit;
                                        /* Idle exit on select timeout? */
#endif  /* HAVE_LAUNCHD */
#ifdef HAVE_AVAHI
  cupsd_timeout_t       *tmo;           /* Next scheduled timed callback */
  long                  tmo_delay;      /* Time before it must be called */
#endif /* HAVE_AVAHI */


#ifdef HAVE_GETEUID
 /*
  * Check for setuid invocation, which we do not support!
  */

  if (getuid() != geteuid())
  {
    fputs("cupsd: Cannot run as a setuid program\n", stderr);
    return (1);
  }
#endif /* HAVE_GETEUID */

 /*
  * Check for command-line arguments...
  */

  fg = 0;

#ifdef HAVE_LAUNCHD
  if (getenv("CUPSD_LAUNCHD"))
  {
    Launchd = 1;
    fg      = 1;
  }
#endif /* HAVE_LAUNCHD */

  for (i = 1; i < argc; i ++)
    if (argv[i][0] == '-')
      for (opt = argv[i] + 1; *opt != '\0'; opt ++)
        switch (*opt)
        {
          case 'C' : /* Run as child with config file */
              run_as_child = 1;
              fg           = -1;

          case 'c' : /* Configuration file */
              i ++;
              if (i >= argc)
              {
                _cupsLangPuts(stderr, _("cupsd: Expected config filename "
                                        "after \"-c\" option."));
                usage(1);
              }

              if (argv[i][0] == '/')
              {
               /*
                * Absolute directory...
                */

                cupsdSetString(&ConfigurationFile, argv[i]);
              }
              else
              {
               /*
                * Relative directory...
                */

                char *current;          /* Current directory */


               /*
                * Allocate a buffer for the current working directory to
                * reduce run-time stack usage; this approximates the
                * behavior of some implementations of getcwd() when they
                * are passed a NULL pointer.
                */

                if ((current = malloc(1024)) == NULL)
                {
                  _cupsLangPuts(stderr,
                                _("cupsd: Unable to get current directory."));
                  return (1);
                }

                if (!getcwd(current, 1024))
                {
                  _cupsLangPuts(stderr,
                                _("cupsd: Unable to get current directory."));
                  free(current);
                  return (1);
                }

                cupsdSetStringf(&ConfigurationFile, "%s/%s", current, argv[i]);
                free(current);
              }
              break;

          case 'f' : /* Run in foreground... */
              fg = 1;
              break;

          case 'F' : /* Run in foreground, but disconnect from terminal... */
              fg = -1;
              break;

          case 'h' : /* Show usage/help */
              usage(0);
              break;

          case 'l' : /* Started by launchd... */
#ifdef HAVE_LAUNCHD
              Launchd = 1;
              fg      = 1;
#else
              _cupsLangPuts(stderr, _("cupsd: launchd(8) support not compiled "
                                      "in, running in normal mode."));
              fg = 0;
#endif /* HAVE_LAUNCHD */
              break;

          case 'p' : /* Stop immediately for profiling */
              fputs("cupsd: -p (startup profiling) is for internal testing "
                    "use only!\n", stderr);
              stop_scheduler = 1;
              fg             = 1;
              break;

          case 'P' : /* Disable security profiles */
              fputs("cupsd: -P (disable security profiles) is for internal "
                    "testing use only!\n", stderr);
              UseProfiles = 0;
              break;

#ifdef __APPLE__
          case 'S' : /* Disable system management functions */
              fputs("cupsd: -S (disable system management) for internal "
                    "testing use only!\n", stderr);
              use_sysman = 0;
              break;
#endif /* __APPLE__ */

          case 't' : /* Test the cupsd.conf file... */
              TestConfigFile = 1;
              fg             = 1;
              break;

          default : /* Unknown option */
              _cupsLangPrintf(stderr, _("cupsd: Unknown option \"%c\" - "
                                        "aborting."), *opt);
              usage(1);
              break;
        }
    else
    {
      _cupsLangPrintf(stderr, _("cupsd: Unknown argument \"%s\" - aborting."),
                      argv[i]);
      usage(1);
    }

  if (!ConfigurationFile)
    cupsdSetString(&ConfigurationFile, CUPS_SERVERROOT "/cupsd.conf");

 /*
  * If the user hasn't specified "-f", run in the background...
  */

  if (!fg)
  {
   /*
    * Setup signal handlers for the parent...
    */

#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
    sigset(SIGUSR1, parent_handler);
    sigset(SIGCHLD, parent_handler);

    sigset(SIGHUP, SIG_IGN);
#elif defined(HAVE_SIGACTION)
    memset(&action, 0, sizeof(action));
    sigemptyset(&action.sa_mask);
    sigaddset(&action.sa_mask, SIGUSR1);
    action.sa_handler = parent_handler;
    sigaction(SIGUSR1, &action, NULL);
    sigaction(SIGCHLD, &action, NULL);

    sigemptyset(&action.sa_mask);
    action.sa_handler = SIG_IGN;
    sigaction(SIGHUP, &action, NULL);
#else
    signal(SIGUSR1, parent_handler);
    signal(SIGCLD, parent_handler);

    signal(SIGHUP, SIG_IGN);
#endif /* HAVE_SIGSET */

    if (fork() > 0)
    {
     /*
      * OK, wait for the child to startup and send us SIGUSR1 or to crash
      * and the OS send us SIGCHLD...  We also need to ignore SIGHUP which
      * might be sent by the init script to restart the scheduler...
      */

      for (; parent_signal == 0;)
        sleep(1);

      if (parent_signal == SIGUSR1)
        return (0);

      if (wait(&i) < 0)
      {
        perror("cupsd");
        return (1);
      }
      else if (WIFEXITED(i))
      {
        fprintf(stderr, "cupsd: Child exited with status %d\n",
                WEXITSTATUS(i));
        return (2);
      }
      else
      {
        fprintf(stderr, "cupsd: Child exited on signal %d\n", WTERMSIG(i));
        return (3);
      }
    }

#ifdef __OpenBSD__
   /*
    * Call _thread_sys_closefrom() so the child process doesn't reset the
    * parent's file descriptors to be blocking.  This is a workaround for a
    * limitation of userland libpthread on OpenBSD.
    */

    _thread_sys_closefrom(0);
#endif /* __OpenBSD__ */

   /*
    * Since CoreFoundation and DBUS both create fork-unsafe data on execution of
    * a program, and since this kind of really unfriendly behavior seems to be
    * more common these days in system libraries, we need to re-execute the
    * background cupsd with the "-C" option to avoid problems.  Unfortunately,
    * we also have to assume that argv[0] contains the name of the cupsd
    * executable - there is no portable way to get the real pathname...
    */

    execlp(argv[0], argv[0], "-C", ConfigurationFile, (char *)0);
    exit(errno);
  }

  if (fg < 1)
  {
   /*
    * Make sure we aren't tying up any filesystems...
    */

    chdir("/");

#ifndef DEBUG
   /*
    * Disable core dumps...
    */

    getrlimit(RLIMIT_CORE, &limit);
    limit.rlim_cur = 0;
    setrlimit(RLIMIT_CORE, &limit);

   /*
    * Disconnect from the controlling terminal...
    */

    setsid();

   /*
    * Close all open files...
    */

    getrlimit(RLIMIT_NOFILE, &limit);

    for (i = 0; i < limit.rlim_cur && i < 1024; i ++)
      close(i);

   /*
    * Redirect stdin/out/err to /dev/null...
    */

    if ((i = open("/dev/null", O_RDONLY)) != 0)
    {
      dup2(i, 0);
      close(i);
    }

    if ((i = open("/dev/null", O_WRONLY)) != 1)
    {
      dup2(i, 1);
      close(i);
    }

    if ((i = open("/dev/null", O_WRONLY)) != 2)
    {
      dup2(i, 2);
      close(i);
    }
#endif /* DEBUG */
  }

 /*
  * Set the timezone info...
  */

  tzset();

#ifdef LC_TIME
  setlocale(LC_TIME, "");
#endif /* LC_TIME */

 /*
  * Set the maximum number of files...
  */

  getrlimit(RLIMIT_NOFILE, &limit);

#if !defined(HAVE_POLL) && !defined(HAVE_EPOLL) && !defined(HAVE_KQUEUE)
  if (limit.rlim_max > FD_SETSIZE)
    MaxFDs = FD_SETSIZE;
  else
#endif /* !HAVE_POLL && !HAVE_EPOLL && !HAVE_KQUEUE */
#ifdef RLIM_INFINITY
  if (limit.rlim_max == RLIM_INFINITY)
    MaxFDs = 16384;
  else
#endif /* RLIM_INFINITY */
    MaxFDs = limit.rlim_max;

  limit.rlim_cur = MaxFDs;

  setrlimit(RLIMIT_NOFILE, &limit);

  cupsdStartSelect();

 /*
  * Read configuration...
  */

  if (!cupsdReadConfiguration())
  {
    if (TestConfigFile)
      printf("%s contains errors\n", ConfigurationFile);
    else
      syslog(LOG_LPR, "Unable to read configuration file \'%s\' - exiting!",
             ConfigurationFile);
    return (1);
  }
  else if (TestConfigFile)
  {
    printf("%s is OK\n", ConfigurationFile);
    return (0);
  }

 /*
  * Clean out old temp files and printer cache data.
  */

  if (!strncmp(TempDir, RequestRoot, strlen(RequestRoot)))
    cupsdCleanFiles(TempDir, NULL);

  cupsdCleanFiles(CacheDir, "*.ipp");

#if HAVE_LAUNCHD
  if (Launchd)
  {
   /*
    * If we were started by launchd get the listen sockets file descriptors...
    */

    launchd_checkin();
    launchd_checkout();
  }
#endif /* HAVE_LAUNCHD */

 /*
  * Startup the server...
  */

  httpInitialize();

  cupsdStartServer();

 /*
  * Catch hangup and child signals and ignore broken pipes...
  */

#ifdef HAVE_SIGSET /* Use System V signals over POSIX to avoid bugs */
  sigset(SIGCHLD, sigchld_handler);
  sigset(SIGHUP, sighup_handler);
  sigset(SIGPIPE, SIG_IGN);
  sigset(SIGTERM, sigterm_handler);
#elif defined(HAVE_SIGACTION)
  memset(&action, 0, sizeof(action));

  sigemptyset(&action.sa_mask);
  sigaddset(&action.sa_mask, SIGTERM);
  sigaddset(&action.sa_mask, SIGCHLD);
  action.sa_handler = sigchld_handler;
  sigaction(SIGCHLD, &action, NULL);

  sigemptyset(&action.sa_mask);
  sigaddset(&action.sa_mask, SIGHUP);
  action.sa_handler = sighup_handler;
  sigaction(SIGHUP, &action, NULL);

  sigemptyset(&action.sa_mask);
  action.sa_handler = SIG_IGN;
  sigaction(SIGPIPE, &action, NULL);

  sigemptyset(&action.sa_mask);
  sigaddset(&action.sa_mask, SIGTERM);
  sigaddset(&action.sa_mask, SIGCHLD);
  action.sa_handler = sigterm_handler;
  sigaction(SIGTERM, &action, NULL);
#else
  signal(SIGCLD, sigchld_handler);      /* No, SIGCLD isn't a typo... */
  signal(SIGHUP, sighup_handler);
  signal(SIGPIPE, SIG_IGN);
  signal(SIGTERM, sigterm_handler);
#endif /* HAVE_SIGSET */

#ifdef __sgi
 /*
  * Try to create a fake lpsched lock file if one is not already there.
  * Some Adobe applications need it under IRIX in order to enable
  * printing...
  */

  if ((fp = cupsFileOpen("/var/spool/lp/SCHEDLOCK", "w")) == NULL)
  {
    syslog(LOG_LPR, "Unable to create fake lpsched lock file "
                    "\"/var/spool/lp/SCHEDLOCK\"\' - %s!",
           strerror(errno));
  }
  else
  {
    fchmod(cupsFileNumber(fp), 0644);
    fchown(cupsFileNumber(fp), User, Group);

    cupsFileClose(fp);
  }
#endif /* __sgi */

 /*
  * Initialize authentication certificates...
  */

  cupsdInitCerts();

 /*
  * If we are running in the background, signal the parent process that
  * we are up and running...
  */

  if (!fg || run_as_child)
  {
   /*
    * Send a signal to the parent process, but only if the parent is
    * not PID 1 (init).  This avoids accidentally shutting down the
    * system on OpenBSD if you CTRL-C the server before it is up...
    */

    i = getppid();      /* Save parent PID to avoid race condition */

    if (i != 1)
      kill(i, SIGUSR1);
  }

#ifdef __APPLE__
 /*
  * Start power management framework...
  */

  if (use_sysman)
    cupsdStartSystemMonitor();
#endif /* __APPLE__ */

 /*
  * Send server-started event...
  */

#ifdef HAVE_LAUNCHD
  if (Launchd)
    cupsdAddEvent(CUPSD_EVENT_SERVER_STARTED, NULL, NULL,
                  "Scheduler started via launchd.");
  else
#endif /* HAVE_LAUNCHD */
  if (fg)
    cupsdAddEvent(CUPSD_EVENT_SERVER_STARTED, NULL, NULL,
                  "Scheduler started in foreground.");
  else
    cupsdAddEvent(CUPSD_EVENT_SERVER_STARTED, NULL, NULL,
                  "Scheduler started in background.");

 /*
  * Start any pending print jobs...
  */

  cupsdCheckJobs();

 /*
  * Loop forever...
  */

  current_time  = time(NULL);
  event_time    = current_time;
  expire_time   = current_time;
  fds           = 1;
  report_time   = 0;
  senddoc_time  = current_time;

  while (!stop_scheduler)
  {
   /*
    * Check if there are dead children to handle...
    */

    if (dead_children)
      process_children();

   /*
    * Check if we need to load the server configuration file...
    */

    if (NeedReload)
    {
     /*
      * Close any idle clients...
      */

      if (cupsArrayCount(Clients) > 0)
      {
        for (con = (cupsd_client_t *)cupsArrayFirst(Clients);
             con;
             con = (cupsd_client_t *)cupsArrayNext(Clients))
          if (con->http.state == HTTP_WAITING)
            cupsdCloseClient(con);
          else
            con->http.keep_alive = HTTP_KEEPALIVE_OFF;

        cupsdPauseListening();
      }

     /*
      * Restart if all clients are closed and all jobs finished, or
      * if the reload timeout has elapsed...
      */

      if ((cupsArrayCount(Clients) == 0 &&
           (cupsArrayCount(PrintingJobs) == 0 || NeedReload != RELOAD_ALL)) ||
          (time(NULL) - ReloadTime) >= ReloadTimeout)
      {
       /*
        * Shutdown the server...
        */

        DoingShutdown = 1;

        cupsdStopServer();

       /*
        * Read configuration...
        */

        if (!cupsdReadConfiguration())
        {
          syslog(LOG_LPR, "Unable to read configuration file \'%s\' - exiting!",
                 ConfigurationFile);
          break;
        }

#if HAVE_LAUNCHD
        if (Launchd)
        {
         /*
          * If we were started by launchd, get the listen socket file
          * descriptors...
          */

          launchd_checkin();
          launchd_checkout();
        }
#endif /* HAVE_LAUNCHD */

       /*
        * Startup the server...
        */

        DoingShutdown = 0;

        cupsdStartServer();

       /*
        * Send a server-restarted event...
        */

        cupsdAddEvent(CUPSD_EVENT_SERVER_RESTARTED, NULL, NULL,
                      "Scheduler restarted.");
      }
    }

   /*
    * Check for available input or ready output.  If cupsdDoSelect()
    * returns 0 or -1, something bad happened and we should exit
    * immediately.
    *
    * Note that we at least have one listening socket open at all
    * times.
    */

    if ((timeout = select_timeout(fds)) > 1 && LastEvent)
      timeout = 1;

#if HAVE_LAUNCHD
   /*
    * If no other work is scheduled and we're being controlled by
    * launchd then timeout after 'LaunchdTimeout' seconds of
    * inactivity...
    */

    if (timeout == 86400 && Launchd && LaunchdTimeout &&
        !cupsArrayCount(ActiveJobs) &&
        (!Browsing || !BrowseLocalProtocols || !cupsArrayCount(Printers)))
    {
      timeout           = LaunchdTimeout;
      launchd_idle_exit = 1;
    }
    else
      launchd_idle_exit = 0;
#endif  /* HAVE_LAUNCHD */

    if ((fds = cupsdDoSelect(timeout)) < 0)
    {
     /*
      * Got an error from select!
      */

#ifdef HAVE_DNSSD
      cupsd_printer_t   *p;             /* Current printer */
#endif /* HAVE_DNSSD */


      if (errno == EINTR)               /* Just interrupted by a signal */
        continue;

     /*
      * Log all sorts of debug info to help track down the problem.
      */

      cupsdLogMessage(CUPSD_LOG_EMERG, "cupsdDoSelect() failed - %s!",
                      strerror(errno));

      for (i = 0, con = (cupsd_client_t *)cupsArrayFirst(Clients);
           con;
           i ++, con = (cupsd_client_t *)cupsArrayNext(Clients))
        cupsdLogMessage(CUPSD_LOG_EMERG,
                        "Clients[%d] = %d, file = %d, state = %d",
                        i, con->http.fd, con->file, con->http.state);

      for (i = 0, lis = (cupsd_listener_t *)cupsArrayFirst(Listeners);
           lis;
           i ++, lis = (cupsd_listener_t *)cupsArrayNext(Listeners))
        cupsdLogMessage(CUPSD_LOG_EMERG, "Listeners[%d] = %d", i, lis->fd);

      cupsdLogMessage(CUPSD_LOG_EMERG, "CGIPipes[0] = %d", CGIPipes[0]);

#ifdef __APPLE__
      cupsdLogMessage(CUPSD_LOG_EMERG, "SysEventPipes[0] = %d",
                      SysEventPipes[0]);
#endif /* __APPLE__ */

      for (job = (cupsd_job_t *)cupsArrayFirst(ActiveJobs);
           job;
           job = (cupsd_job_t *)cupsArrayNext(ActiveJobs))
        cupsdLogMessage(CUPSD_LOG_EMERG, "Jobs[%d] = %d < [%d %d] > [%d %d]",
                        job->id,
                        job->status_buffer ? job->status_buffer->fd : -1,
                        job->print_pipes[0], job->print_pipes[1],
                        job->back_pipes[0], job->back_pipes[1]);

#ifdef HAVE_DNSSD
      for (p = (cupsd_printer_t *)cupsArrayFirst(Printers);
           p;
           p = (cupsd_printer_t *)cupsArrayNext(Printers))
        cupsdLogMessage(CUPSD_LOG_EMERG, "printer[%s] reg_name=\"%s\"", p->name,
                        p->reg_name ? p->reg_name : "(null)");
#endif /* HAVE_DNSSD */

      break;
    }

    current_time = time(NULL);

   /*
    * Write dirty config/state files...
    */

    if (DirtyCleanTime && current_time >= DirtyCleanTime)
      cupsdCleanDirty();

#ifdef __APPLE__
   /*
    * If we are going to sleep and still have pending jobs, stop them after
    * a period of time...
    */

    if (SleepJobs > 0 && current_time >= SleepJobs &&
        cupsArrayCount(PrintingJobs) > 0)
    {
      SleepJobs = 0;
      cupsdStopAllJobs(CUPSD_JOB_DEFAULT, 5);
    }
#endif /* __APPLE__ */

#ifdef HAVE_AVAHI
   /*
    * If a timed callback is due, run it.
    */

    tmo = cupsdNextTimeout(&tmo_delay);
    if (tmo && tmo_delay == 0)
      cupsdRunTimeout(tmo);
#endif /* HAVE_AVAHI */

#ifndef __APPLE__
   /*
    * Update the network interfaces once a minute...
    */

    if ((current_time - netif_time) >= 60)
    {
      netif_time  = current_time;
      NetIFUpdate = 1;
    }
#endif /* !__APPLE__ */

#if HAVE_LAUNCHD
   /*
    * If no other work was scheduled and we're being controlled by launchd
    * then timeout after 'LaunchdTimeout' seconds of inactivity...
    */

    if (!fds && launchd_idle_exit)
    {
      cupsdLogMessage(CUPSD_LOG_INFO,
                      "Printer sharing is off and there are no jobs pending, "
                      "will restart on demand.");
      stop_scheduler = 1;
      break;
    }
#endif /* HAVE_LAUNCHD */

   /*
    * Resume listening for new connections as needed...
    */

    if (ListeningPaused && ListeningPaused <= current_time &&
        cupsArrayCount(Clients) < MaxClients)
      cupsdResumeListening();

   /*
    * Expire subscriptions and unload completed jobs as needed...
    */

    if (current_time > expire_time)
    {
      if (cupsArrayCount(Subscriptions) > 0)
        cupsdExpireSubscriptions(NULL, NULL);

      cupsdUnloadCompletedJobs();

      expire_time = current_time;
    }

#ifndef HAVE_AUTHORIZATION_H
   /*
    * Update the root certificate once every 5 minutes if we have client
    * connections...
    */

    if ((current_time - RootCertTime) >= RootCertDuration && RootCertDuration &&
        !RunUser && cupsArrayCount(Clients))
    {
     /*
      * Update the root certificate...
      */

      cupsdDeleteCert(0);
      cupsdAddCert(0, "root", NULL);
    }
#endif /* !HAVE_AUTHORIZATION_H */

   /*
    * Check for new data on the client sockets...
    */

    for (con = (cupsd_client_t *)cupsArrayFirst(Clients);
         con;
         con = (cupsd_client_t *)cupsArrayNext(Clients))
    {
     /*
      * Process pending data in the input buffer...
      */

      if (con->http.used)
      {
        cupsdReadClient(con);
        continue;
      }

     /*
      * Check the activity and close old clients...
      */

      activity = current_time - Timeout;
      if (con->http.activity < activity && !con->pipe_pid)
      {
        cupsdLogMessage(CUPSD_LOG_DEBUG,
                        "Closing client %d after %d seconds of inactivity...",
                        con->http.fd, Timeout);

        cupsdCloseClient(con);
        continue;
      }
    }

   /*
    * Update any pending multi-file documents...
    */

    if ((current_time - senddoc_time) >= 10)
    {
      cupsdCheckJobs();
      cupsdCleanJobs();
      senddoc_time = current_time;
    }

   /*
    * Log statistics at most once a minute when in debug mode...
    */

    if ((current_time - report_time) >= 60 && LogLevel >= CUPSD_LOG_DEBUG)
    {
      size_t            string_count,   /* String count */
                        alloc_bytes,    /* Allocated string bytes */
                        total_bytes;    /* Total string bytes */
#ifdef HAVE_MALLINFO
      struct mallinfo   mem;            /* Malloc information */


      mem = mallinfo();
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: malloc-arena=%lu", mem.arena);
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: malloc-used=%lu",
                      mem.usmblks + mem.uordblks);
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: malloc-free=%lu",
                      mem.fsmblks + mem.fordblks);
#endif /* HAVE_MALLINFO */

      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: clients=%d",
                      cupsArrayCount(Clients));
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: jobs=%d",
                      cupsArrayCount(Jobs));
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: jobs-active=%d",
                      cupsArrayCount(ActiveJobs));
      cupsdLogMessage(CUPSD_LOG_DEBUG, "Report: printers=%d",
                      cupsArrayCount(Printers));

      string_count = _cupsStrStatistics(&alloc_bytes, &total_bytes);
      cupsdLogMessage(CUPSD_LOG_DEBUG,
                      "Report: stringpool-string-count=" CUPS_LLFMT,
                      CUPS_LLCAST string_count);
      cupsdLogMessage(CUPSD_LOG_DEBUG,
                      "Report: stringpool-alloc-bytes=" CUPS_LLFMT,
                      CUPS_LLCAST alloc_bytes);
      cupsdLogMessage(CUPSD_LOG_DEBUG,
                      "Report: stringpool-total-bytes=" CUPS_LLFMT,
                      CUPS_LLCAST total_bytes);

      report_time = current_time;
    }

   /*
    * Handle OS-specific event notification for any events that have
    * accumulated.  Don't send these more than once a second...
    */

    if (LastEvent && (current_time - event_time) >= 1)
    {
#ifdef HAVE_NOTIFY_POST
      if (LastEvent & (CUPSD_EVENT_PRINTER_ADDED |
                       CUPSD_EVENT_PRINTER_DELETED |
                       CUPSD_EVENT_PRINTER_MODIFIED))
      {
        cupsdLogMessage(CUPSD_LOG_DEBUG2,
                        "notify_post(\"com.apple.printerListChange\")");
        notify_post("com.apple.printerListChange");
      }

      if (LastEvent & CUPSD_EVENT_PRINTER_STATE_CHANGED)
      {
        cupsdLogMessage(CUPSD_LOG_DEBUG2,
                        "notify_post(\"com.apple.printerHistoryChange\")");
        notify_post("com.apple.printerHistoryChange");
      }

      if (LastEvent & (CUPSD_EVENT_JOB_STATE_CHANGED |
                       CUPSD_EVENT_JOB_CONFIG_CHANGED |
                       CUPSD_EVENT_JOB_PROGRESS))
      {
        cupsdLogMessage(CUPSD_LOG_DEBUG2,
                        "notify_post(\"com.apple.jobChange\")");
        notify_post("com.apple.jobChange");
      }
#endif /* HAVE_NOTIFY_POST */

     /*
      * Reset the accumulated events...
      */

      LastEvent  = CUPSD_EVENT_NONE;
      event_time = current_time;
    }
  }

 /*
  * Log a message based on what happened...
  */

  if (stop_scheduler)
  {
    cupsdLogMessage(CUPSD_LOG_INFO, "Scheduler shutting down normally.");
    cupsdAddEvent(CUPSD_EVENT_SERVER_STOPPED, NULL, NULL,
                  "Scheduler shutting down normally.");
  }
  else
  {
    cupsdLogMessage(CUPSD_LOG_ERROR,
                    "Scheduler shutting down due to program error.");
    cupsdAddEvent(CUPSD_EVENT_SERVER_STOPPED, NULL, NULL,
                  "Scheduler shutting down due to program error.");
  }

 /*
  * Close all network clients...
  */

  DoingShutdown = 1;

  cupsdStopServer();

#ifdef HAVE_LAUNCHD
 /*
  * Update the launchd KeepAlive file as needed...
  */

  if (Launchd)
    launchd_checkout();
#endif /* HAVE_LAUNCHD */

 /*
  * Stop all jobs...
  */

  cupsdFreeAllJobs();

#ifdef __APPLE__
 /*
  * Stop monitoring system event monitoring...
  */

  if (use_sysman)
    cupsdStopSystemMonitor();
#endif /* __APPLE__ */

#ifdef HAVE_GSSAPI
 /*
  * Free the scheduler's Kerberos context...
  */

#  ifdef __APPLE__
 /*
  * If the weak-linked GSSAPI/Kerberos library is not present, don't try
  * to use it...
  */

  if (krb5_init_context != NULL)
#  endif /* __APPLE__ */
  if (KerberosContext)
    krb5_free_context(KerberosContext);
#endif /* HAVE_GSSAPI */

#ifdef __sgi
 /*
  * Remove the fake IRIX lpsched lock file, but only if the existing
  * file is not a FIFO which indicates that the real IRIX lpsched is
  * running...
  */

  if (!stat("/var/spool/lp/FIFO", &statbuf))
    if (!S_ISFIFO(statbuf.st_mode))
      unlink("/var/spool/lp/SCHEDLOCK");
#endif /* __sgi */

  cupsdStopSelect();

  return (!stop_scheduler);
}


/*
 * 'cupsdAddString()' - Copy and add a string to an array.
 */

int                                     /* O  - 1 on success, 0 on failure */
cupsdAddString(cups_array_t **a,        /* IO - String array */
               const char   *s)         /* I  - String to copy and add */
{
  if (!*a)
    *a = cupsArrayNew3((cups_array_func_t)strcmp, NULL,
                       (cups_ahash_func_t)NULL, 0,
                       (cups_acopy_func_t)_cupsStrAlloc,
                       (cups_afree_func_t)_cupsStrFree);

  return (cupsArrayAdd(*a, (char *)s));
}


/*
 * 'cupsdCheckProcess()' - Tell the main loop to check for dead children.
 */

void
cupsdCheckProcess(void)
{
 /*
  * Flag that we have dead children...
  */

  dead_children = 1;
}


/*
 * 'cupsdClearString()' - Clear a string.
 */

void
cupsdClearString(char **s)              /* O - String value */
{
  if (s && *s)
  {
    _cupsStrFree(*s);
    *s = NULL;
  }
}


/*
 * 'cupsdFreeStrings()' - Free an array of strings.
 */

void
cupsdFreeStrings(cups_array_t **a)      /* IO - String array */
{
  if (*a)
  {
    cupsArrayDelete(*a);
    *a = NULL;
  }
}


/*
 * 'cupsdHoldSignals()' - Hold child and termination signals.
 */

void
cupsdHoldSignals(void)
{
#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
  sigset_t              newmask;        /* New POSIX signal mask */
#endif /* HAVE_SIGACTION && !HAVE_SIGSET */


  holdcount ++;
  if (holdcount > 1)
    return;

#ifdef HAVE_SIGSET
  sighold(SIGTERM);
  sighold(SIGCHLD);
#elif defined(HAVE_SIGACTION)
  sigemptyset(&newmask);
  sigaddset(&newmask, SIGTERM);
  sigaddset(&newmask, SIGCHLD);
  sigprocmask(SIG_BLOCK, &newmask, &holdmask);
#endif /* HAVE_SIGSET */
}


/*
 * 'cupsdReleaseSignals()' - Release signals for delivery.
 */

void
cupsdReleaseSignals(void)
{
  holdcount --;
  if (holdcount > 0)
    return;

#ifdef HAVE_SIGSET
  sigrelse(SIGTERM);
  sigrelse(SIGCHLD);
#elif defined(HAVE_SIGACTION)
  sigprocmask(SIG_SETMASK, &holdmask, NULL);
#endif /* HAVE_SIGSET */
}


/*
 * 'cupsdSetString()' - Set a string value.
 */

void
cupsdSetString(char       **s,          /* O - New string */
               const char *v)           /* I - String value */
{
  if (!s || *s == v)
    return;

  if (*s)
    _cupsStrFree(*s);

  if (v)
    *s = _cupsStrAlloc(v);
  else
    *s = NULL;
}


/*
 * 'cupsdSetStringf()' - Set a formatted string value.
 */

void
cupsdSetStringf(char       **s,         /* O - New string */
                const char *f,          /* I - Printf-style format string */
                ...)                    /* I - Additional args as needed */
{
  char          v[4096];                /* Formatting string value */
  va_list       ap;                     /* Argument pointer */
  char          *olds;                  /* Old string */


  if (!s)
    return;

  olds = *s;

  if (f)
  {
    va_start(ap, f);
    vsnprintf(v, sizeof(v), f, ap);
    va_end(ap);

    *s = _cupsStrAlloc(v);
  }
  else
    *s = NULL;

  if (olds)
    _cupsStrFree(olds);
}


#ifdef HAVE_LAUNCHD
/*
 * 'launchd_checkin()' - Check-in with launchd and collect the listening fds.
 */

static void
launchd_checkin(void)
{
  size_t                i,              /* Looping var */
                        count;          /* Number of listeners */
  launch_data_t         ld_msg,         /* Launch data message */
                        ld_resp,        /* Launch data response */
                        ld_array,       /* Launch data array */
                        ld_sockets,     /* Launch data sockets dictionary */
                        tmp;            /* Launch data */
  cupsd_listener_t      *lis;           /* Listeners array */
  http_addr_t           addr;           /* Address variable */
  socklen_t             addrlen;        /* Length of address */
  int                   fd;             /* File descriptor */
  char                  s[256];         /* String addresss */


  cupsdLogMessage(CUPSD_LOG_DEBUG, "launchd_checkin: pid=%d", (int)getpid());

 /*
  * Check-in with launchd...
  */

  ld_msg = launch_data_new_string(LAUNCH_KEY_CHECKIN);
  if ((ld_resp = launch_msg(ld_msg)) == NULL)
  {
    cupsdLogMessage(CUPSD_LOG_ERROR,
                    "launchd_checkin: launch_msg(\"" LAUNCH_KEY_CHECKIN
                    "\") IPC failure");
    exit(EXIT_FAILURE);
    return; /* anti-compiler-warning */
  }

  if (launch_data_get_type(ld_resp) == LAUNCH_DATA_ERRNO)
  {
    errno = launch_data_get_errno(ld_resp);
    cupsdLogMessage(CUPSD_LOG_ERROR, "launchd_checkin: Check-in failed: %s",
                    strerror(errno));
    exit(EXIT_FAILURE);
    return; /* anti-compiler-warning */
  }

 /*
  * Get the sockets dictionary...
  */

  if ((ld_sockets = launch_data_dict_lookup(ld_resp, LAUNCH_JOBKEY_SOCKETS))
          == NULL)
  {
    cupsdLogMessage(CUPSD_LOG_ERROR,
                    "launchd_checkin: No sockets found to answer requests on!");
    exit(EXIT_FAILURE);
    return; /* anti-compiler-warning */
  }

 /*
  * Get the array of listener sockets...
  */

  if ((ld_array = launch_data_dict_lookup(ld_sockets, "Listeners")) == NULL)
  {
    cupsdLogMessage(CUPSD_LOG_ERROR,
                    "launchd_checkin: No sockets found to answer requests on!");
    exit(EXIT_FAILURE);
    return; /* anti-compiler-warning */
  }

 /*
  * Add listening fd(s) to the Listener array...
  */

  if (launch_data_get_type(ld_array) == LAUNCH_DATA_ARRAY)
  {
    count = launch_data_array_get_count(ld_array);

    for (i = 0; i < count; i ++)
    {
     /*
      * Get the launchd file descriptor and address...
      */

      if ((tmp = launch_data_array_get_index(ld_array, i)) != NULL)
      {
        fd      = launch_data_get_fd(tmp);
        addrlen = sizeof(addr);

        if (getsockname(fd, (struct sockaddr *)&addr, &addrlen))
        {
          cupsdLogMessage(CUPSD_LOG_ERROR,
                          "launchd_checkin: Unable to get local address - %s",
                          strerror(errno));
          continue;
        }

       /*
        * Try to match the launchd socket address to one of the listeners...
        */

        for (lis = (cupsd_listener_t *)cupsArrayFirst(Listeners);
             lis;
             lis = (cupsd_listener_t *)cupsArrayNext(Listeners))
          if (httpAddrEqual(&lis->address, &addr))
            break;

       /*
        * Add a new listener If there's no match...
        */

        if (lis)
        {
          cupsdLogMessage(CUPSD_LOG_DEBUG,
                  "launchd_checkin: Matched existing listener %s with fd %d...",
                  httpAddrString(&(lis->address), s, sizeof(s)), fd);
        }
        else
        {
          cupsdLogMessage(CUPSD_LOG_DEBUG,
                  "launchd_checkin: Adding new listener %s with fd %d...",
                  httpAddrString(&addr, s, sizeof(s)), fd);

          if ((lis = calloc(1, sizeof(cupsd_listener_t))) == NULL)
          {
            cupsdLogMessage(CUPSD_LOG_ERROR,
                            "launchd_checkin: Unable to allocate listener - "
                            "%s.", strerror(errno));
            exit(EXIT_FAILURE);
          }

          cupsArrayAdd(Listeners, lis);

          memcpy(&lis->address, &addr, sizeof(lis->address));
        }

        lis->fd = fd;

#  ifdef HAVE_SSL
        if (_httpAddrPort(&(lis->address)) == 443)
          lis->encryption = HTTP_ENCRYPT_ALWAYS;
#  endif /* HAVE_SSL */
      }
    }
  }

  launch_data_free(ld_msg);
  launch_data_free(ld_resp);
}


/*
 * 'launchd_checkout()' - Update the launchd KeepAlive file as needed.
 */

static void
launchd_checkout(void)
{
  int   fd;                             /* File descriptor */


 /*
  * Create or remove the launchd KeepAlive file based on whether
  * there are active jobs, polling, browsing for remote printers or
  * shared printers to advertise...
  */

  if (cupsArrayCount(ActiveJobs) ||
      (Browsing && BrowseLocalProtocols && cupsArrayCount(Printers)))
  {
    cupsdLogMessage(CUPSD_LOG_DEBUG,
                    "Creating launchd keepalive file \"" CUPS_KEEPALIVE
                    "\"...");

    if ((fd = open(CUPS_KEEPALIVE, O_RDONLY | O_CREAT | O_EXCL, S_IRUSR)) >= 0)
      close(fd);
  }
  else
  {
    cupsdLogMessage(CUPSD_LOG_DEBUG,
                    "Removing launchd keepalive file \"" CUPS_KEEPALIVE
                    "\"...");

    unlink(CUPS_KEEPALIVE);
  }
}
#endif /* HAVE_LAUNCHD */


/*
 * 'parent_handler()' - Catch USR1/CHLD signals...
 */

static void
parent_handler(int sig)                 /* I - Signal */
{
 /*
  * Store the signal we got from the OS and return...
  */

  parent_signal = sig;
}


/*
 * 'process_children()' - Process all dead children...
 */

static void
process_children(void)
{
  int           status;                 /* Exit status of child */
  int           pid,                    /* Process ID of child */
                job_id;                 /* Job ID of child */
  cupsd_job_t   *job;                   /* Current job */
  int           i;                      /* Looping var */
  char          name[1024];             /* Process name */
  const char    *type;                  /* Type of program */


  cupsdLogMessage(CUPSD_LOG_DEBUG2, "process_children()");

 /*
  * Reset the dead_children flag...
  */

  dead_children = 0;

 /*
  * Collect the exit status of some children...
  */

#ifdef HAVE_WAITPID
  while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
#elif defined(HAVE_WAIT3)
  while ((pid = wait3(&status, WNOHANG, NULL)) > 0)
#else
  if ((pid = wait(&status)) > 0)
#endif /* HAVE_WAITPID */
  {
   /*
    * Collect the name of the process that finished...
    */

    cupsdFinishProcess(pid, name, sizeof(name), &job_id);

   /*
    * Delete certificates for CGI processes...
    */

    if (pid)
      cupsdDeleteCert(pid);

   /*
    * Handle completed job filters...
    */

    if (job_id > 0)
      job = cupsdFindJob(job_id);
    else
      job  = NULL;

    if (job)
    {
      for (i = 0; job->filters[i]; i ++)
        if (job->filters[i] == pid)
          break;

      if (job->filters[i] || job->backend == pid)
      {
       /*
        * OK, this process has gone away; what's left?
        */

        if (job->filters[i])
        {
          job->filters[i] = -pid;
          type            = "Filter";
        }
        else
        {
          job->backend = -pid;
          type         = "Backend";
        }

        if (status && status != SIGTERM && status != SIGKILL &&
            status != SIGPIPE && job->status >= 0)
        {
         /*
          * An error occurred; save the exit status so we know to stop
          * the printer or cancel the job when all of the filters finish...
          *
          * A negative status indicates that the backend failed and the
          * printer needs to be stopped.
          */

          if (job->filters[i])
            job->status = status;       /* Filter failed */
          else
            job->status = -status;      /* Backend failed */

          if (job->state_value == IPP_JOB_PROCESSING &&
              job->status_level > CUPSD_LOG_ERROR &&
              (job->filters[i] || !WIFEXITED(status)))
          {
            char        message[1024];  /* New printer-state-message */


            job->status_level = CUPSD_LOG_ERROR;

            snprintf(message, sizeof(message), "%s failed", type);

            if (job->printer)
            {
              strlcpy(job->printer->state_message, message,
                       sizeof(job->printer->state_message));
            }

            if (!job->attrs)
              cupsdLoadJob(job);

            if (!job->printer_message && job->attrs)
            {
              if ((job->printer_message =
                       ippFindAttribute(job->attrs, "job-printer-state-message",
                                        IPP_TAG_TEXT)) == NULL)
                job->printer_message = ippAddString(job->attrs, IPP_TAG_JOB,
                                                    IPP_TAG_TEXT,
                                                    "job-printer-state-message",
                                                    NULL, NULL);
            }

            if (job->printer_message)
              cupsdSetString(&(job->printer_message->values[0].string.text),
                             message);
          }
        }

       /*
        * If this is not the last file in a job, see if all of the
        * filters are done, and if so move to the next file.
        */

        if (job->current_file < job->num_files && job->printer)
        {
          for (i = 0; job->filters[i] < 0; i ++);

          if (!job->filters[i] &&
              (!job->printer->pc || !job->printer->pc->single_file ||
               job->backend <= 0))
          {
           /*
            * Process the next file...
            */

            cupsdContinueJob(job);
          }
        }
        else if (job->state_value >= IPP_JOB_CANCELED)
        {
         /*
          * Remove the job from the active list if there are no processes still
          * running for it...
          */

          for (i = 0; job->filters[i] < 0; i++);

          if (!job->filters[i] && job->backend <= 0)
            cupsArrayRemove(ActiveJobs, job);
        }
      }
    }

   /*
    * Show the exit status as needed, ignoring SIGTERM and SIGKILL errors
    * since they come when we kill/end a process...
    */

    if (status == SIGTERM || status == SIGKILL)
    {
      cupsdLogJob(job, CUPSD_LOG_DEBUG,
                  "PID %d (%s) was terminated normally with signal %d.", pid,
                  name, status);
    }
    else if (status == SIGPIPE)
    {
      cupsdLogJob(job, CUPSD_LOG_DEBUG,
                  "PID %d (%s) did not catch or ignore signal %d.", pid, name,
                  status);
    }
    else if (status)
    {
      if (WIFEXITED(status))
      {
        int code = WEXITSTATUS(status); /* Exit code */

        if (code > 100)
          cupsdLogJob(job, CUPSD_LOG_DEBUG,
                      "PID %d (%s) stopped with status %d (%s)", pid, name,
                      code, strerror(code - 100));
        else
          cupsdLogJob(job, CUPSD_LOG_DEBUG,
                      "PID %d (%s) stopped with status %d.", pid, name, code);
      }
      else
        cupsdLogJob(job, CUPSD_LOG_DEBUG, "PID %d (%s) crashed on signal %d.",
                    pid, name, WTERMSIG(status));

      if (LogLevel < CUPSD_LOG_DEBUG)
        cupsdLogJob(job, CUPSD_LOG_INFO,
                    "Hint: Try setting the LogLevel to \"debug\" to find out "
                    "more.");
    }
    else
      cupsdLogJob(job, CUPSD_LOG_DEBUG, "PID %d (%s) exited with no errors.",
                  pid, name);
  }

 /*
  * If wait*() is interrupted by a signal, tell main() to call us again...
  */

  if (pid < 0 && errno == EINTR)
    dead_children = 1;
}


/*
 * 'select_timeout()' - Calculate the select timeout value.
 *
 */

static long                             /* O - Number of seconds */
select_timeout(int fds)                 /* I - Number of descriptors returned */
{
  long                  timeout;        /* Timeout for select */
  time_t                now;            /* Current time */
  cupsd_client_t        *con;           /* Client information */
  cupsd_job_t           *job;           /* Job information */
  cupsd_subscription_t  *sub;           /* Subscription information */
  const char            *why;           /* Debugging aid */
#ifdef HAVE_AVAHI
  cupsd_timeout_t       *tmo;           /* Timed callback */
  long                  tmo_delay;      /* Seconds before calling it */
#endif /* HAVE_AVAHI */


 /*
  * Check to see if any of the clients have pending data to be
  * processed; if so, the timeout should be 0...
  */

  for (con = (cupsd_client_t *)cupsArrayFirst(Clients);
       con;
       con = (cupsd_client_t *)cupsArrayNext(Clients))
    if (con->http.used > 0)
      return (0);

 /*
  * If select has been active in the last second (fds > 0) or we have
  * many resources in use then don't bother trying to optimize the
  * timeout, just make it 1 second.
  */

  if (fds > 0 || cupsArrayCount(Clients) > 50)
    return (1);

 /*
  * Otherwise, check all of the possible events that we need to wake for...
  */

  now     = time(NULL);
  timeout = now + 86400;                /* 86400 == 1 day */
  why     = "do nothing";

#ifdef __APPLE__
 /*
  * When going to sleep, wake up to cancel jobs that don't complete in time.
  */

  if (SleepJobs > 0 && SleepJobs < timeout)
  {
    timeout = SleepJobs;
    why     = "cancel jobs before sleeping";
  }
#endif /* __APPLE__ */

#ifdef HAVE_AVAHI
 /*
  * See if there are any scheduled timed callbacks to run.
  */

  if ((tmo = cupsdNextTimeout(&tmo_delay)) != NULL &&
      (now + tmo_delay) < timeout)
  {
    timeout = tmo_delay;
    why     = "run a timed callback";
  }
#endif /* HAVE_AVAHI */

 /*
  * Check whether we are accepting new connections...
  */

  if (ListeningPaused > 0 && cupsArrayCount(Clients) < MaxClients &&
      ListeningPaused < timeout)
  {
    if (ListeningPaused <= now)
      timeout = now;
    else
      timeout = ListeningPaused;

    why = "resume listening";
  }

 /*
  * Check the activity and close old clients...
  */

  for (con = (cupsd_client_t *)cupsArrayFirst(Clients);
       con;
       con = (cupsd_client_t *)cupsArrayNext(Clients))
    if ((con->http.activity + Timeout) < timeout)
    {
      timeout = con->http.activity + Timeout;
      why     = "timeout a client connection";
    }

 /*
  * Write out changes to configuration and state files...
  */

  if (DirtyCleanTime && timeout > DirtyCleanTime)
  {
    timeout = DirtyCleanTime;
    why     = "write dirty config/state files";
  }

 /*
  * Check for any active jobs...
  */

  for (job = (cupsd_job_t *)cupsArrayFirst(ActiveJobs);
       job;
       job = (cupsd_job_t *)cupsArrayNext(ActiveJobs))
  {
    if (job->kill_time && job->kill_time < timeout)
    {
      timeout = job->kill_time;
      why     = "kill unresponsive jobs";
    }
    else if (job->cancel_time && job->cancel_time < timeout)
    {
      timeout = job->cancel_time;
      why     = "cancel stuck jobs";
    }
    else if (job->state_value == IPP_JOB_HELD && job->hold_until < timeout)
    {
      timeout = job->hold_until;
      why     = "release held jobs";
    }
    else if (job->state_value == IPP_JOB_PENDING && timeout > (now + 10))
    {
      timeout = now + 10;
      why     = "start pending jobs";
      break;
    }
  }

#ifdef HAVE_MALLINFO
 /*
  * Log memory usage every minute...
  */

  if (LogLevel >= CUPSD_LOG_DEBUG && (mallinfo_time + 60) < timeout)
  {
    timeout = mallinfo_time + 60;
    why     = "display memory usage";
  }
#endif /* HAVE_MALLINFO */

 /*
  * Expire subscriptions as needed...
  */

  for (sub = (cupsd_subscription_t *)cupsArrayFirst(Subscriptions);
       sub;
       sub = (cupsd_subscription_t *)cupsArrayNext(Subscriptions))
    if (!sub->job && sub->expire && sub->expire < timeout)
    {
      timeout = sub->expire;
      why     = "expire subscription";
    }

 /*
  * Adjust from absolute to relative time.  We add 1 second to the timeout since
  * events occur after the timeout expires, and limit the timeout to 86400
  * seconds (1 day) to avoid select() timeout limits present on some operating
  * systems...
  */

  timeout = timeout - now + 1;

  if (timeout < 1)
    timeout = 1;
  else if (timeout > 86400)
    timeout = 86400;

 /*
  * Log and return the timeout value...
  */

  cupsdLogMessage(CUPSD_LOG_DEBUG2, "select_timeout(%d): %ld seconds to %s",
                  fds, timeout, why);

  return (timeout);
}


/*
 * 'sigchld_handler()' - Handle 'child' signals from old processes.
 */

static void
sigchld_handler(int sig)                /* I - Signal number */
{
  (void)sig;

 /*
  * Flag that we have dead children...
  */

  dead_children = 1;

 /*
  * Reset the signal handler as needed...
  */

#if !defined(HAVE_SIGSET) && !defined(HAVE_SIGACTION)
  signal(SIGCLD, sigchld_handler);
#endif /* !HAVE_SIGSET && !HAVE_SIGACTION */
}


/*
 * 'sighup_handler()' - Handle 'hangup' signals to reconfigure the scheduler.
 */

static void
sighup_handler(int sig)                 /* I - Signal number */
{
  (void)sig;

  NeedReload = RELOAD_ALL;
  ReloadTime = time(NULL);

#if !defined(HAVE_SIGSET) && !defined(HAVE_SIGACTION)
  signal(SIGHUP, sighup_handler);
#endif /* !HAVE_SIGSET && !HAVE_SIGACTION */
}


/*
 * 'sigterm_handler()' - Handle 'terminate' signals that stop the scheduler.
 */

static void
sigterm_handler(int sig)                /* I - Signal number */
{
  (void)sig;    /* remove compiler warnings... */

 /*
  * Flag that we should stop and return...
  */

  stop_scheduler = 1;
}


/*
 * 'usage()' - Show scheduler usage.
 */

static void
usage(int status)                       /* O - Exit status */
{
  FILE  *fp = status ? stderr : stdout; /* Output file */


  _cupsLangPuts(fp, _("Usage: cupsd [options]"));
  _cupsLangPuts(fp, _("Options:"));
  _cupsLangPuts(fp, _("  -c config-file          Load alternate configuration "
                      "file."));
  _cupsLangPuts(fp, _("  -f                      Run in the foreground."));
  _cupsLangPuts(fp, _("  -F                      Run in the foreground but "
                      "detach from console."));
  _cupsLangPuts(fp, _("  -h                      Show this usage message."));
  _cupsLangPuts(fp, _("  -l                      Run cupsd from launchd(8)."));
  _cupsLangPuts(fp, _("  -t                      Test the configuration "
                      "file."));

  exit(status);
}


/*
 * End of "$Id: main.c 7925 2008-09-10 17:47:26Z mike $".
 */