Implemented watchdog

HISTORY

@@ -409,3 +409,7 @@ Video Disk Recorder Revision History
   that every timer may use the primary interface.
 - The 'active' field of a timer will now be explicitly set to '1' if the user
   modifies an active timer (see FORMATS for details).
+- The new command line option -w can be used to activate a watchdog that makes
+  VDR exit in case the main program loop does not respond for more than the
+  given number of seconds. This is mainly useful in combination with the new
+  'runvdr' script that restarts VDR in case is has exited.

INSTALL

@@ -15,7 +15,7 @@ If you have the DVB driver source in a different location
 you will have to change the definition of DVBDIR in the
 Makefile.
 
-This program requires the card driver version 0.8.1 or higher
+This program requires the card driver version 0.8.2 or higher
 to work properly. You need to load the dvb.o module *without* option
 'outstream=0' (previous versions of VDR required this option to have
 the driver supply the data in AV_PES format; as of version 0.70 VDR
@@ -71,6 +71,13 @@ If the program shall run as a daemon, use the --daemon option. This
 will completely detach it from the terminal and will continue as a
 background process.
 
+Automatic restart in case of hangups:
+-------------------------------------
+
+If you run VDR using the 'runvdr' shell script it will use the built-in
+watchdog timer to restart the program in case something happens that
+causes a program hangup.
+
 Command line options:
 ---------------------
 

runvdr

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+DVBDIR='../DVB/driver'
+VDRCMD='./vdr -w 60'
+
+while test 1; do
+#      (cd $DVBDIR; make reload)
+#      sleep 3
+      if $VDRCMD; then exit; fi
+      date
+      echo "restarting VDR"
+      sleep 10
+      done

vdr.c

@@ -22,7 +22,7 @@
  *
  * The project's page is at http://www.cadsoft.de/people/kls/vdr
  *
- * $Id: vdr.c 1.53 2001/02/11 14:51:44 kls Exp $
+ * $Id: vdr.c 1.54 2001/02/24 16:18:43 kls Exp $
  */
 
 #include <getopt.h>
@@ -55,15 +55,25 @@ static void SignalHandler(int signum)
   signal(signum, SignalHandler);
 }
 
+static void Watchdog(int signum)
+{
+  // Something terrible must have happened that prevented the 'alarm()' from
+  // being called in time, so let's get out of here:
+  esyslog(LOG_ERR, "PANIC: watchdog timer expired - exiting!");
+  exit(1);
+}
+
 int main(int argc, char *argv[])
 {
   // Command line options:
 
 #define DEFAULTSVDRPPORT 2001
+#define DEFAULTWATCHDOG     0 // seconds
 
   int SVDRPport = DEFAULTSVDRPPORT;
   const char *ConfigDirectory = NULL;
   bool DaemonMode = false;
+  int WatchdogTimeout = DEFAULTWATCHDOG;
 
   static struct option long_options[] = {
       { "config",   required_argument, NULL, 'c' },
@@ -73,12 +83,13 @@ int main(int argc, char *argv[])
       { "log",      required_argument, NULL, 'l' },
       { "port",     required_argument, NULL, 'p' },
       { "video",    required_argument, NULL, 'v' },
+      { "watchdog", required_argument, NULL, 'w' },
       { 0 }
     };
   
   int c;
   int option_index = 0;
-  while ((c = getopt_long(argc, argv, "c:dD:hl:p:v:", long_options, &option_index)) != -1) {
+  while ((c = getopt_long(argc, argv, "c:dD:hl:p:v:w:", long_options, &option_index)) != -1) {
         switch (c) {
           case 'c': ConfigDirectory = optarg;
                     break;
@@ -107,10 +118,13 @@ int main(int argc, char *argv[])
                            "  -p PORT,  --port=PORT    use PORT for SVDRP (default: %d)\n"
                            "                           0 turns off SVDRP\n"
                            "  -v DIR,   --video=DIR    use DIR as video directory (default is %s)\n"
+                           "  -w SEC,   --watchdog=SEC activate the watchdog timer with a timeout of SEC\n"
+                           "                           seconds (default: %d); '0' disables the watchdog\n"
                            "\n"
                            "Report bugs to <vdr-bugs@cadsoft.de>\n",
                            DEFAULTSVDRPPORT,
-                           VideoDirectory
+                           VideoDirectory,
+                           DEFAULTWATCHDOG
                            );
                     return 0;
                     break;
@@ -135,6 +149,16 @@ int main(int argc, char *argv[])
                     while (optarg && *optarg && optarg[strlen(optarg) - 1] == '/')
                           optarg[strlen(optarg) - 1] = 0;
                     break;
+          case 'w': if (isnumber(optarg)) {
+                       int t = atoi(optarg);
+                       if (t >= 0) {
+                          WatchdogTimeout = t;
+                          break;
+                          }
+                       }
+                    fprintf(stderr, "vdr: invalid watchdog timeout: %s\n", optarg);
+                    abort();
+                    break;
           default:  abort();
           }
         }
@@ -213,6 +237,8 @@ int main(int argc, char *argv[])
   if (signal(SIGINT,  SignalHandler) == SIG_IGN) signal(SIGINT,  SIG_IGN);
   if (signal(SIGTERM, SignalHandler) == SIG_IGN) signal(SIGTERM, SIG_IGN);
   if (signal(SIGPIPE, SignalHandler) == SIG_IGN) signal(SIGPIPE, SIG_IGN);
+  if (WatchdogTimeout > 0)
+     if (signal(SIGALRM, Watchdog)   == SIG_IGN) signal(SIGALRM, SIG_IGN);
 
   // Main program loop:
 
@@ -221,8 +247,22 @@ int main(int argc, char *argv[])
   int LastChannel = -1;
   int PreviousChannel = cDvbApi::CurrentChannel();
   time_t LastActivity = time(NULL);
+  int MaxLatencyTime = 0;
+
+  if (WatchdogTimeout > 0) {
+     dsyslog(LOG_INFO, "setting watchdog timer to %d seconds", WatchdogTimeout);
+     alarm(WatchdogTimeout); // Initial watchdog timer start
+     }
 
   while (!Interrupted) {
+        // Restart the Watchdog timer:
+        if (WatchdogTimeout > 0) {
+           int LatencyTime = WatchdogTimeout - alarm(WatchdogTimeout);
+           if (LatencyTime > MaxLatencyTime) {
+              MaxLatencyTime = LatencyTime;
+              dsyslog(LOG_INFO, "max. latency time %d seconds", MaxLatencyTime);
+              }
+           }
         // Channel display:
         if (!EITScanner.Active() && cDvbApi::CurrentChannel() != LastChannel) {
            if (!Menu)
@@ -344,6 +384,8 @@ int main(int argc, char *argv[])
   delete ReplayControl;
   delete Interface;
   cDvbApi::Cleanup();
+  if (WatchdogTimeout > 0)
+     dsyslog(LOG_INFO, "max. latency time %d seconds", MaxLatencyTime);
   isyslog(LOG_INFO, "exiting");
   if (SysLogLevel > 0)
      closelog();