init: halt on SIGPWR too

Most init processes implement a handler for SIGPWR that gracefully
stops all child processes when shutting down a machine. Some other
technologies rely on this signal - e.g. Busybox powered LXC
containers.

This patch makes busybox init halt when receiving SIGPWR.

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/init/init.c b/init/init.c
index c63bba1ff..d29328c36 100644
--- a/init/init.c
+++ b/init/init.c
@@ -789,7 +789,7 @@ static void run_shutdown_and_kill_processes(void)
  * and only one will be remembered and acted upon.
  */
 
-/* The SIGUSR[12]/SIGTERM handler */
+/* The SIGPWR/SIGUSR[12]/SIGTERM handler */
 static void halt_reboot_pwoff(int sig) NORETURN;
 static void halt_reboot_pwoff(int sig)
 {
@@ -1103,8 +1103,8 @@ int init_main(int argc UNUSED_PARAM, char **argv)
 
                 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
                  * then parse_inittab() simply adds in some default
-                 * actions(i.e., INIT_SCRIPT and a pair
-                 * of "askfirst" shells */
+                 * actions (i.e., INIT_SCRIPT and a pair
+                 * of "askfirst" shells) */
                 parse_inittab();
         }
 
@@ -1135,6 +1135,7 @@ int init_main(int argc UNUSED_PARAM, char **argv)
                 struct sigaction sa;
 
                 bb_signals(0
+                        + (1 << SIGPWR)  /* halt */
                         + (1 << SIGUSR1) /* halt */
                         + (1 << SIGTERM) /* reboot */
                         + (1 << SIGUSR2) /* poweroff */