[PATCH 1/1] init: disable init actions that failed to open the TTY

[Carmelo AMOROSO]

On 2/7/2011 9:49 AM, Carmelo Amoroso wrote:
> Add a new configurable feature that allow the init to disable
> actions of type ASKFIRST and RESPAWN that have failed to open
> the TTY preventing to make them looping forever.
> If a SIGHUP is sent to init to reload the inittab, the processes
> linked to these action are enabled again to give them another chance
> to run.
> This feature can be enabled by switching on CONFIG_FEATURE_DESCHEDULE_ON_TTY_FAIL.
> 
> Signed-off-by: Carmelo Amoroso <carmelo.amoroso at st.com>
> ---
> init/init.c | 38 ++++++++++++++++++++++++++++++++------
> 1 files changed, 32 insertions(+), 6 deletions(-)
> 
> diff --git a/init/init.c b/init/init.c
> index 586e34a..2367939 100644
> --- a/init/init.c
> +++ b/init/init.c
> @@ -37,6 +37,16 @@
> //config: sent to init, this option will make init kill the processes
> //config: that have been removed.
> //config:
> +//config:config FEATURE_DESCHEDULE_ON_TTY_FAIL
> +//config: bool "Support descheduling processes that have failed in opening TTYs"
> +//config: default n
> +//config: depends on FEATURE_USE_INITTAB
> +//config: help
> +//config: When respawn entries failed at opening a TTY, this option will make init
> +//config: to disable the processes preventing to loop forever.
> +//config: If a SIGHUP is sent to init to reload the inittab, these processes
> +//config: are enabled again to give them a new chance to run.
> +//config:
> //config:config FEATURE_KILL_DELAY
> //config: int "How long to wait between TERM and KILL (0 - send TERM only)" if 
> FEATURE_KILL_REMOVED
> //config: range 0 1024
> @@ -182,6 +192,7 @@ struct init_action {
> struct init_action *next;
> pid_t pid;
> uint8_t action_type;
> + uint8_t disabled;
> char terminal[CONSOLE_NAME_SIZE];
> char command[COMMAND_SIZE];
> };
> @@ -568,10 +579,10 @@ static void run_actions(int action_type)
> waitfor(pid);
> }
> if (a->action_type & (RESPAWN | ASKFIRST)) {
> - /* Only run stuff with pid == 0. If pid != 0,
> + /* Only run stuff with pid == 0 and enabled. If pid != 0,
> * it is already running
> */
> - if (a->pid == 0)
> + if (a->pid == 0 && !a->disabled)
> a->pid = run(a);
> }
> }
> @@ -884,9 +895,11 @@ static void reload_inittab(void)
> 
> message(L_LOG, "reloading /etc/inittab");
> 
> - /* Disable old entries */
> - for (a = init_action_list; a; a = a->next)
> + /* Disable old entries and reset enable status */
> + for (a = init_action_list; a; a = a->next) {
> a->action_type = 0;
> + a->disabled = 0;
> + }
> 
> /* Append new entries, or modify existing entries
> * (incl. setting a->action_type) if cmd and device name
> @@ -1134,20 +1147,33 @@ int init_main(int argc UNUSED_PARAM, char **argv)
> while (1) {
> pid_t wpid;
> struct init_action *a;
> + int status;
> 
> /* If signals happen _in_ the wait, they interrupt it,
> * bb_signals_recursive_norestart set them up that way
> */
> - wpid = waitpid(-1, NULL, maybe_WNOHANG);
> + wpid = waitpid(-1, &status, maybe_WNOHANG);
> if (wpid <= 0)
> break;
> 
> a = mark_terminated(wpid);
> - if (a) {
> +#ifdef ENABLE_FEATURE_DESCHEDULE_ON_TTY_FAIL
> + if(WIFEXITED(status) && (WEXITSTATUS(status) == EXIT_FAILURE))
> + /* Mark the action as disabled, so they will not be restarted */
> + a->disabled = 1;
> +#endif
> + if (a && !a->disabled) {
> message(L_LOG, "process '%s' (pid %d) exited. "
> "Scheduling for restart.",
> a->command, wpid);
> }
> +#ifdef ENABLE_FEATURE_DESCHEDULE_ON_TTY_FAIL
> + if (a && a->disabled) {
> + message(L_CONSOLE, "process '%s' (pid %d) exited. "
> + "De-scheduled.",
> + a->command, wpid);
> + }
> +#endif
> /* See if anyone else is waiting to be reaped */
> maybe_WNOHANG = WNOHANG;
> }
> --
> 1.7.3.5
> 


Hi,
any comments ?

cheers,
carmelo