diff options
| -rw-r--r-- | init/halt.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/init/halt.c b/init/halt.c index c6c857f..e6dcb1c 100644 --- a/init/halt.c +++ b/init/halt.c @@ -24,6 +24,17 @@ //config: help //config: Stop all processes and reboot the system. //config: +//config:config FEATURE_WAIT_FOR_INIT +//config: bool "Before signaling init, make sure it is ready for it" +//config: default y +//config: depends on HALT || POWEROFF || REBOOT +//config: help +//config: In rare cases, poweroff may be commanded by firmware to OS +//config: even before init process exists. On Linux, this spawns +//config: "/sbin/poweroff" very early. This option adds code +//config: which checks that init is ready to receive poweroff +//config: commands. Code size increase of ~80 bytes. +//config: //config:config FEATURE_CALL_TELINIT //config: bool "Call telinit on shutdown and reboot" //config: default y @@ -108,6 +119,47 @@ static void write_wtmp(void) #define write_wtmp() ((void)0) #endif +#if ENABLE_FEATURE_WAIT_FOR_INIT +/* In Linux, "poweroff" may be spawned even before init. + * For example, with ACPI: + * linux/drivers/acpi/bus.c: + * static void sb_notify_work(struct work_struct *dummy) + * orderly_poweroff(true); + * linux/kernel/reboot.c: + * static int run_cmd(const char *cmd) + * ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); + * poweroff_cmd[] = "/sbin/poweroff"; + * static int __orderly_poweroff(bool force) + * ret = run_cmd(poweroff_cmd); + * + * We want to make sure init exists and listens to signals. + */ +static int init_was_not_there(void) +{ + enum { initial = 5 }; /* 5 seconds should be plenty for timeout */ + int cnt = initial - 1; + + /* Just existence of PID 1 does not mean it installed + * the handlers already. + */ +#if 0 + while (kill(1, 0) != 0 && --cnt >= 0) + sleep(1); +#endif + /* ... so let's wait for some evidence a usual startup event, + * mounting of /proc, happened. By that time init should be ready + * for signals. + */ + while (access("/proc/meminfo", F_OK) != 0 && --cnt >= 0) + sleep(1); + + /* Does it look like init wasn't there? */ + return (cnt != initial - 1); +} +#else + /* Assume it's always there */ +# define init_was_not_there() 0 +#endif int halt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int halt_main(int argc UNUSED_PARAM, char **argv) @@ -171,6 +223,8 @@ int halt_main(int argc UNUSED_PARAM, char **argv) if (!ENABLE_FEATURE_CALL_TELINIT) { /* bbox init assumed */ rc = kill(1, signals[which]); + if (init_was_not_there()) + rc = kill(1, signals[which]); } else { /* SysV style init assumed */ /* runlevels: |