Running motion on a Nokia N810

Question

Hi -

I've compiled motion for a Nokia N810 tablet, and it runs fine in non-daemon mode. But in daemon mode, it starts up successfully, but dies. Not quite sure where to start debugging this... ideas?

[0] Processing thread 0 - config file /home/user/camera/motion.conf
[0] Motion 3.2.11 Started
[0] Motion going to daemon mode 

Environment

Motion version:	3.2.11
ffmpeg version:
Libraries:
Server OS:	Nokia N810, kernel 2.6.21

-- JonathanMiner - 11 Dec 2008

Follow Up

Could be a good idea to upload your config file ... but as a quick guess

1-. Check process_id_file value ( probably motion has not permission to create file)

2-. Check rights of value for target_dir

ummm also log files ... not sure where are stored on that gadget , motion uses syslog.

-- AngelCarpintero - 12 Dec 2008

Update

When I originally posed the question, the process_id_file was "./motion.pid" and target_dir was commented out. I've since changed them to be:

daemon on 
process_id_file "/home/user/camera/motion.pid"
target_dir /home/user/camera

Logging is challenging... "dmesg" doesn't show any "motion" related stuff, and there is no syslog daemon. I did notice this morning, that when running in daemon mode, the pid file does not get updated. In non-daemon mode (motion -n) it does get updated. Additionally, I made a small change to the motion.c file to examine the behavior of fork():

--- motion.c.dist    2008-09-21 19:20:58.000000000 -0400
+++ motion.c    2008-12-15 10:57:05.000000000 -0500
@@ -1935,6 +1935,7 @@
 static void become_daemon(void)
 {
     int i;
+    pid_t pid;
     FILE *pidf = NULL;    
     struct sigaction sig_ign_action;
 
@@ -1948,7 +1949,13 @@
     sigemptyset(&sig_ign_action.sa_mask);
 
     /* fork */
-    if (fork()) {
+    pid = fork();
+    
+    if (pid == -1) {
+        motion_log(-1, 0, "Motion failed to go into daemon mode");
+        exit(0);
+    }
+    else if (pid == 0) {
         motion_log(-1, 0, "Motion going to daemon mode");
         exit(0);
     }
@@ -1962,7 +1969,7 @@
         pidf = fopen(cnt_list[0]->conf.pid_file, "w+");
     
         if (pidf ) {
-            (void)fprintf(pidf, "%d\n", getpid());
+            (void)fprintf(pidf, "%d\n", pid);
             fclose(pidf);
         } else {
             motion_log(LOG_ERR, 1, "Exit motion, cannot create process id file (pid file) %s",
@@ -1978,7 +1985,7 @@
     }
 
 #if (defined(BSD))
-    setpgrp(0, getpid());
+    setpgrp(0, pid);
 #else
     setpgrp();
 #endif /* BSD */ 

After patching, and modifing the config file, the behavior has changed slightly:

When running "./motion -n", lots of screen output as expected

When running "./motion", goes into daemon mode, but control not returned to the shell.

When running "./motion &", goes into daemon mode, and control returned to the shell.

-- JonathanMiner - 15 Dec 2008

Answer

Nokia N810 runs Maemo OS ( based in linux ) but probably exec() , fork() and probably other libc fuctions could have a different behaviour.

Best way to fix this is to get the SDK/Documentation of porting linux app to Maemo.

-- AngelCarpintero - 16 Nov 2009