init: restore possibility to reload inittab even before we finish initialization

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/init/init.c b/init/init.c
index 5240e47a5165c617991952244abc0bd205b03934..14136859f7102f3ed85ed7076150982277953378 100644 (file)
--- a/init/init.c
+++ b/init/init.c
@@ -40,9 +40,9 @@
 #define ONCE        0x04
 /*
  * NB: while SYSINIT/WAIT/ONCE are being processed,
- * SIGHUP ("reread /etc/inittab") will be ignored.
- * Rationale: it would be ambiguous whether SYSINIT/WAIT/ONCE
- * need to be rerun or not.
+ * SIGHUP ("reread /etc/inittab") will be processed only after
+ * each group of actions. If new inittab adds, say, a SYSINIT action,
+ * it will not be run, since init is already "past SYSINIT stage".
  */
 /* Start these after ONCE are started, restart on exit */
 #define RESPAWN     0x08
@@ -754,12 +754,12 @@ static void reload_inittab(void)
 
        /* Disable old entries */
        for (a = init_action_list; a; a = a->next)
-               a->action_type = ONCE;
+               a->action_type = 0;
 
        /* Append new entries, or modify existing entries
-        * (set a->action_type) if cmd and device name
+        * (incl. setting a->action_type) if cmd and device name
         * match new ones. End result: only entries with
-        * a->action_type == ONCE are stale.
+        * a->action_type == 0 are stale.
         */
        parse_inittab();
 
@@ -767,24 +767,26 @@ static void reload_inittab(void)
        /* Kill stale entries */
        /* Be nice and send SIGTERM first */
        for (a = init_action_list; a; a = a->next)
-               if (a->action_type == ONCE && a->pid != 0)
+               if (a->action_type == 0 && a->pid != 0)
                        kill(a->pid, SIGTERM);
        if (CONFIG_FEATURE_KILL_DELAY) {
                /* NB: parent will wait in NOMMU case */
                if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
                        sleep(CONFIG_FEATURE_KILL_DELAY);
                        for (a = init_action_list; a; a = a->next)
-                               if (a->action_type == ONCE && a->pid != 0)
+                               if (a->action_type == 0 && a->pid != 0)
                                        kill(a->pid, SIGKILL);
                        _exit(EXIT_SUCCESS);
                }
        }
 #endif
 
-       /* Remove stale (ONCE) and not useful (SYSINIT,WAIT) entries */
+       /* Remove stale entries and SYSINIT entries.
+        * We never rerun SYSINIT entries anyway,
+        * removing them too saves a few bytes */
        nextp = &init_action_list;
        while ((a = *nextp) != NULL) {
-               if (a->action_type & (ONCE | SYSINIT | WAIT)) {
+               if ((a->action_type & ~SYSINIT) == 0) {
                        *nextp = a->next;
                        free(a);
                } else {
@@ -943,6 +945,12 @@ int init_main(int argc UNUSED_PARAM, char **argv)
                bb_signals_recursive_norestart((1 << SIGINT), record_signo);
        }
 
+       /* Set up "reread /etc/inittab" handler.
+        * Handler is set up without SA_RESTART, it will interrupt syscalls.
+        */
+       if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
+               bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
+
        /* Now run everything that needs to be run */
        /* First run the sysinit command */
        run_actions(SYSINIT);
@@ -953,12 +961,6 @@ int init_main(int argc UNUSED_PARAM, char **argv)
        /* Next run anything to be run only once */
        run_actions(ONCE);
 
-       /* Set up "reread /etc/inittab" handler.
-        * Handler is set up without SA_RESTART, it will interrupt syscalls.
-        */
-       if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
-               bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
-
        /* Now run the looping stuff for the rest of forever.
         */
        while (1) {