[BusyBox] init patch to reload /etc/inittab

[Andrew Flegg]

Hi,

Here's a pretty crude patch to reload /etc/inittab when init receives a
SIGHUP. The mailing list archives weren't entirely clear on whether or
not it should already happen, but didn't appear to be.

The patch:
   * Adds a new function, reload_signal() which just calls
     parse_inittab() and run_actions(RESPAWN)
     
   * Before entering the while (1) loop set up SIGHUP to call
     reload_signal()

   * Modify new_init_action to skip the action if the same command
     already exists on the same terminal

This last bit means that changing already running entries is a bit
hairy as you can end up with, for example, two shells running on the
same virtual console. However, for solely adding/removing entries this patch
seems to work quite well.

Cheers,

Andrew

-- 
Andrew Flegg -- mailto:andrew at bleb.org  |  http://www.bleb.org/
-------------- next part --------------
--- busybox/init/init.c	2003-07-05 09:38:40.000000000 +0100
+++ busybox-unstable/init/init.c	2003-07-15 10:30:24.000000000 +0100
@@ -853,7 +853,14 @@
 	}
 
 	/* Append to the end of the list */
-	for (a = init_action_list; a && a->next; a = a->next);
+	for (a = init_action_list; a && a->next; a = a->next) {
+		/* don't enter action if it's already in the list */
+		if ((strcmp(a->command, command) == 0) && 
+		    (strcmp(a->terminal, cons) ==0)) {
+			free(new_action);
+			return;
+		}
+	}
 	if (a) {
 		a->next = new_action;
 	} else {
@@ -1028,7 +1035,14 @@
 #endif							/* CONFIG_FEATURE_USE_INITTAB */
 }
 
-
+static void reload_signal(int sig)
+{
+        message(LOG, "Reloading /etc/inittab");
+        parse_inittab();
+	run_actions(RESPAWN);
+        return;
+}
+                                                                                
 extern int init_main(int argc, char **argv)
 {
 	struct init_action *a;
@@ -1126,6 +1140,9 @@
 		loop_forever();
 	}
 
+	/* Redefine SIGHUP to reread /etc/inittab */
+	signal(SIGHUP, reload_signal);
+
 	/* Now run the looping stuff for the rest of forever */
 	while (1) {
 		/* run the respawn stuff */