Ensure watchdog always starts with the starting time of the thread. Add watchdog bark count. On the third bark, execute an unfixable error script if present.

audio_alsa.c

@@ -136,8 +136,7 @@ static void help(void) {
 
 void set_alsa_out_dev(char *dev) { alsa_out_dev = dev; }
 
-
-//assuming pthread cancellation is disabled
+// assuming pthread cancellation is disabled
 int open_mixer() {
   int response = 0;
   if (hardware_mixer) {
@@ -181,7 +180,7 @@ int open_mixer() {
   return response;
 }
 
-//assuming pthread cancellation is disabled
+// assuming pthread cancellation is disabled
 void close_mixer() {
   if (alsa_mix_handle) {
     snd_mixer_close(alsa_mix_handle);
@@ -189,7 +188,7 @@ void close_mixer() {
   }
 }
 
-//assuming pthread cancellation is disabled
+// assuming pthread cancellation is disabled
 void do_snd_mixer_selem_set_playback_dB_all(snd_mixer_elem_t *mix_elem, double vol) {
   if (snd_mixer_selem_set_playback_dB_all(mix_elem, vol, 0) != 0) {
     debug(1, "Can't set playback volume accurately to %f dB.", vol);
@@ -200,7 +199,7 @@ void do_snd_mixer_selem_set_playback_dB_all(snd_mixer_elem_t *mix_elem, double v
 }
 
 static int init(int argc, char **argv) {
-	// for debugging
+  // for debugging
   snd_output_stdio_attach(&output, stdout, 0);
 
   // debug(2,"audio_alsa init called.");
@@ -506,8 +505,7 @@ static int init(int argc, char **argv) {
   } else {
     debug(1, "alsa: no hardware mixer selected.");
   }
-  
-  usleep(100000); // see if it makes a difference
+
   alsa_mix_handle = NULL;
   return response;
 }
@@ -517,7 +515,7 @@ static void deinit(void) {
   stop();
 }
 
-//assuming pthread cancellation is disabled
+// assuming pthread cancellation is disabled
 int actual_open_alsa_device(void) {
   // the alsa mutex is already acquired when this is called
   const snd_pcm_uframes_t minimal_buffer_headroom =
@@ -884,11 +882,10 @@ int actual_open_alsa_device(void) {
       break;
     }
   }
-  usleep(100000); // see if it makes a difference
   return 0;
 }
 
-int open_alsa_device(void)  {
+int open_alsa_device(void) {
   int result;
   int oldState;
   pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldState); // make this un-cancellable
@@ -911,10 +908,9 @@ static void start(int i_sample_rate, int i_sample_format) {
 
   frame_index = 0;
   measurement_data_is_valid = 0;
-  usleep(100000); // see if it makes a difference
 }
 
-//assuming pthread cancellation is disabled
+// assuming pthread cancellation is disabled
 int my_snd_pcm_delay(snd_pcm_t *pcm, snd_pcm_sframes_t *delayp) {
   int ret;
   snd_pcm_status_t *alsa_snd_pcm_status;
@@ -1165,7 +1161,6 @@ static void flush(void) {
     measurement_data_is_valid = 0;
     alsa_handle = NULL;
   }
-  usleep(100000); // see if it makes a difference
   debug_mutex_unlock(&alsa_mutex, 3);
   pthread_cleanup_pop(0); // release the mutex
   pthread_setcancelstate(oldState, NULL);
@@ -1303,6 +1298,6 @@ void do_mute(int mute_state_requested) {
       close_mixer();
     }
   }
-  mute_request_pending = 0;  
+  mute_request_pending = 0;
   pthread_setcancelstate(oldState, NULL);
 }

common.c

@@ -739,6 +739,38 @@ void command_start(void) {
     }
   }
 }
+void command_execute(const char *command) {
+  // this has a cancellation point if waiting is enabled
+  if (command) {
+    /*Spawn a child to run the program.*/
+    pid_t pid = fork();
+    if (pid == 0) { /* child process */
+      int argC;
+      char **argV;
+      if (poptParseArgvString(command, &argC, (const char ***)&argV) !=
+          0) // note that argV should be free()'d after use, but we expect this fork to exit
+             // eventually.
+        debug(1, "Can't decipher command arguments in \"%s\".", command);
+      else {
+        // debug(1,"Executing command %s",command);
+        execv(argV[0], argV);
+        warn("Execution of command \"%s\" failed to start", command);
+        debug(1, "Error executing command \"%s\".", command);
+        exit(127); /* only if execv fails */
+      }
+    } else {
+      if (config.cmd_blocking) { /* pid!=0 means parent process and if blocking is true, wait for
+                                    process to finish */
+        pid_t rc = waitpid(pid, 0, 0); /* wait for child to exit */
+        if (rc != pid) {
+          warn("Execution of command \"%s\" returned an error.", command);
+          debug(1, "Command \"%s\" finished with error %d", command, errno);
+        }
+      }
+      // debug(1,"Continue after on-unfixable command");
+    }
+  }
+}
 
 void command_stop(void) {
   // this has a cancellation point if waiting is enabled

common.h

@@ -148,7 +148,7 @@ typedef struct {
   int debugger_show_relative_time; // in the debug message, display the time since the last one
   int statistics_requested, use_negotiated_latencies;
   enum playback_mode_type playback_mode;
-  char *cmd_start, *cmd_stop, *cmd_set_volume;
+  char *cmd_start, *cmd_stop, *cmd_set_volume, *cmd_unfixable;
   int cmd_blocking, cmd_start_returns_output;
   double tolerance; // allow this much drift before attempting to correct it
   enum stuffing_type packet_stuffing;
@@ -296,6 +296,7 @@ int config_set_lookup_bool(config_t *cfg, char *where, int *dst);
 
 void command_start(void);
 void command_stop(void);
+void command_execute(const char *command);
 void command_set_volume(double volume);
 
 int mkpath(const char *path, mode_t mode);

player.h

@@ -84,11 +84,12 @@ typedef struct {
   SOCKADDR remote, local;
   volatile int stop;
   volatile int running;
+  volatile uint64_t watchdog_bark_time;
+  volatile int watchdog_barks; // number of times the watchdog has timed out and done something
+
   time_t playstart;
   pthread_t thread, timer_requester, rtp_audio_thread, rtp_control_thread, rtp_timing_thread,
       player_watchdog_thread;
-  volatile int64_t watchdog_bark_time;
-  // pthread_t *ptp;
 
   // buffers to delete on exit
   signed short *tbuf;

rtsp.c

@@ -283,11 +283,25 @@ void *player_watchdog_thread_code(void *arg) {
         uint64_t ct = config.timeout; // go from int to 64-bit int
 
         if (time_since_last_bark >= ct) {
-          debug(1, "Connection %d: As Yeats almost said, \"Too long a silence / can make a stone "
-                   "of the heart\".",
-                conn->connection_number);
-          conn->stop = 1;
-          pthread_cancel(conn->thread);
+          conn->watchdog_barks++;
+          if (conn->watchdog_barks == 1) {
+            debug(1, "Connection %d: As Yeats almost said, \"Too long a silence / can make a stone "
+                     "of the heart\".",
+                  conn->connection_number);
+            conn->stop = 1;
+            pthread_cancel(conn->thread);
+          } else if (conn->watchdog_barks == 3) {
+            if (config.cmd_unfixable) {
+              warn("Connection %d: An unfixable error has been detected. Executing the "
+                   "\"run_this_if_an_unfixable_error_is_detected\" command.",
+                   conn->connection_number);
+              command_execute(config.cmd_unfixable);
+            } else {
+              warn("Connection %d: An unfixable error has been detected. \"No "
+                   "run_this_if_an_unfixable_error_is_detected\" command provided -- nothing done.",
+                   conn->connection_number);
+            }
+          }
         }
       }
     }
@@ -2144,7 +2158,8 @@ void msg_cleanup_function(void *arg) {
 static void *rtsp_conversation_thread_func(void *pconn) {
   rtsp_conn_info *conn = pconn;
 
-  // create the watchdog mutex and start the watchdog thread;
+  // create the watchdog mutex, initialise the watchdog time and start the watchdog thread;
+  conn->watchdog_bark_time = get_absolute_time_in_fp();
   pthread_mutex_init(&conn->watchdog_mutex, NULL);
   pthread_create(&conn->player_watchdog_thread, NULL, &player_watchdog_thread_code, (void *)conn);
 
@@ -2393,12 +2408,11 @@ void rtsp_listen_loop(void) {
     tv.tv_usec = 0;
     if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, (const char *)&tv, sizeof tv) == -1)
       debug(1, "Error %d setting send timeout for rtsp writeback.", errno);
-    
+
     tv.tv_sec = 30; // 30 seconds read timeout
     tv.tv_usec = 0;
-     if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof tv) == -1)
+    if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof tv) == -1)
       debug(1, "Error %d setting send timeout for rtsp writeback.", errno);
-   
 
 #ifdef IPV6_V6ONLY
     // some systems don't support v4 access on v6 sockets, but some do.

scripts/shairport-sync.conf

@@ -53,6 +53,7 @@ sessioncontrol =
 {
 //	run_this_before_play_begins = "/full/path/to/application and args"; // make sure the application has executable permission. If it's a script, include the shebang (#!/bin/...) on the first line
 //	run_this_after_play_ends = "/full/path/to/application and args"; // make sure the application has executable permission. If it's a script, include the shebang (#!/bin/...) on the first line
+//	run_this_if_an_unfixable_error_is_detected = "/full/path/to/application and args"; // if a problem occurs that can't be cleared. It might restart the whole device.
 //	wait_for_completion = "no"; // set to "yes" to get Shairport Sync to wait until the "run_this..." applications have terminated before continuing
 //	allow_session_interruption = "no"; // set to "yes" to allow another device to interrupt Shairport Sync while it's playing from an existing audio source
 //	session_timeout = 120; // wait for this number of seconds after a source disappears before terminating the session and becoming available again.

shairport.c

@@ -721,6 +721,11 @@ int parse_options(int argc, char **argv) {
         config.cmd_stop = (char *)str;
       }
 
+      if (config_lookup_string(config.cfg,
+                               "sessioncontrol.run_this_if_an_unfixable_error_is_detected", &str)) {
+        config.cmd_unfixable = (char *)str;
+      }
+
       if (config_lookup_string(config.cfg, "sessioncontrol.wait_for_completion", &str)) {
         if (strcasecmp(str, "no") == 0)
           config.cmd_blocking = 0;