[dm-devel] [PATCH v2] multipath-tools: handle exit signal immediately

[Benjamin Marzinski]

On Tue, Jan 30, 2018 at 03:16:24PM +0100, Martin Wilck wrote:
> multipathd shouldn't try to service any more client connections
> when it receives an exit signal. Moreover, ppoll() can return
> success even if signals occured. So check for reconfigure or
> log_reset signals after handling pending client requests.
> 
> Based on an analysis by Chongyun Wu.
> 
> Reported-by: Chongyun Wu <wu.chongyun at h3c.com>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>  multipathd/main.c   | 6 ++++--
>  multipathd/main.h   | 2 +-
>  multipathd/uxlsnr.c | 7 +++++--
>  3 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 27cf234623d0..8e96f5dd2d7f 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -2184,12 +2184,15 @@ signal_set(int signo, void (*func) (int))
>  }
>  
>  void
> -handle_signals(void)
> +handle_signals(bool nonfatal)
>  {
>  	if (exit_sig) {
>  		condlog(2, "exit (signal)");
> +		exit_sig = 0;
>  		exit_daemon();
>  	}
> +	if (!nonfatal)
> +		return;
>  	if (reconfig_sig) {
>  		condlog(2, "reconfigure (signal)");
>  		set_config_state(DAEMON_CONFIGURE);
> @@ -2200,7 +2203,6 @@ handle_signals(void)
>  		log_reset("multipathd");
>  		pthread_mutex_unlock(&logq_lock);
>  	}
> -	exit_sig = 0;
>  	reconfig_sig = 0;
>  	log_reset_sig = 0;
>  }
> diff --git a/multipathd/main.h b/multipathd/main.h
> index ededdaba32fe..e8140feaf291 100644
> --- a/multipathd/main.h
> +++ b/multipathd/main.h
> @@ -38,6 +38,6 @@ int mpath_pr_event_handle(struct path *pp);
>  void * mpath_pr_event_handler_fn (void * );
>  int update_map_pr(struct multipath *mpp);
>  void * mpath_pr_event_handler_fn (void * pathp );
> -void handle_signals(void);
> +void handle_signals(bool);
>  
>  #endif /* MAIN_H */
> diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c
> index 98ac25a68c43..dc116cf2515b 100644
> --- a/multipathd/uxlsnr.c
> +++ b/multipathd/uxlsnr.c
> @@ -221,9 +221,10 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
>  		/* most of our life is spent in this call */
>  		poll_count = ppoll(polls, i, &sleep_time, &mask);
>  
> +		handle_signals(false);
>  		if (poll_count == -1) {
>  			if (errno == EINTR) {
> -				handle_signals();
> +				handle_signals(true);
>  				continue;
>  			}
>  
> @@ -233,7 +234,7 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
>  		}
>  
>  		if (poll_count == 0) {
> -			handle_signals();
> +			handle_signals(true);
>  			continue;
>  		}
>  
> @@ -292,6 +293,8 @@ void * uxsock_listen(uxsock_trigger_fn uxsock_trigger, void * trigger_data)
>  				FREE(inbuf);
>  			}
>  		}
> +		/* see if we got a non-fatal signal */
> +		handle_signals(true);
>  
>  		/* see if we got a new client */
>  		if (polls[0].revents & POLLIN) {
> -- 
> 2.16.1

Looks good to me.

Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>