[PATCH weston 3/3] text: Switch to weston_client_start instead of weston_client_launch

[Bryce Harrington]

On Thu, Jun 25, 2015 at 03:49:49PM -0500, Derek Foreman wrote:
> We really don't want to deal with sighups and pids.  It's far easier
> to just deal with the client destroyed signal to respawn the input method.
> 
> Inspiration taken from Pekka's commit 826dc14ec43b92d
> 
> This fixes a potential crash on shutdown.  If the input method client
> pointer is still set (sighup handler hasn't run) but the client is
> already destroyed, a call to text_backend_destroy() will try to destroy
> the client a second time resulting in a segfault.
> 
> Signed-off-by: Derek Foreman <derekf at osg.samsung.com>

Pekka might want to review this, but LGTM for landing post-release.

Reviewed-by: Bryce Harrington <bryce at osg.samsung.com>

> ---
>  src/text-backend.c | 47 +++++++++++++++++++++++++++++------------------
>  1 file changed, 29 insertions(+), 18 deletions(-)
> 
> diff --git a/src/text-backend.c b/src/text-backend.c
> index 59011c8..609bd71 100644
> --- a/src/text-backend.c
> +++ b/src/text-backend.c
> @@ -100,13 +100,13 @@ struct text_backend {
>  
>  	struct {
>  		char *path;
> -		struct weston_process process;
>  		struct wl_client *client;
>  
>  		unsigned deathcount;
>  		uint32_t deathstamp;
>  	} input_method;
>  
> +	struct wl_listener client_listener;
>  	struct wl_listener seat_created_listener;
>  };
>  
> @@ -919,14 +919,9 @@ input_method_init_seat(struct weston_seat *seat)
>  static void launch_input_method(struct text_backend *text_backend);
>  
>  static void
> -handle_input_method_sigchld(struct weston_process *process, int status)
> +respawn_input_method_process(struct text_backend *text_backend)
>  {
>  	uint32_t time;
> -	struct text_backend *text_backend =
> -		container_of(process, struct text_backend, input_method.process);
> -
> -	text_backend->input_method.process.pid = 0;
> -	text_backend->input_method.client = NULL;
>  
>  	/* if input_method dies more than 5 times in 10 seconds, give up */
>  	time = weston_compositor_get_time();
> @@ -937,15 +932,27 @@ handle_input_method_sigchld(struct weston_process *process, int status)
>  
>  	text_backend->input_method.deathcount++;
>  	if (text_backend->input_method.deathcount > 5) {
> -		weston_log("input_method died, giving up.\n");
> +		weston_log("input_method disconnected, giving up.\n");
>  		return;
>  	}
>  
> -	weston_log("input_method died, respawning...\n");
> +	weston_log("input_method disconnected, respawning...\n");
>  	launch_input_method(text_backend);
>  }
>  
>  static void
> +input_method_client_notifier(struct wl_listener *listener, void *data)
> +{
> +	struct text_backend *text_backend;
> +
> +	text_backend = container_of(listener, struct text_backend,
> +				    client_listener);
> +
> +	text_backend->input_method.client = NULL;
> +	respawn_input_method_process(text_backend);
> +}
> +
> +static void
>  launch_input_method(struct text_backend *text_backend)
>  {
>  	if (!text_backend->input_method.path)
> @@ -954,18 +961,19 @@ launch_input_method(struct text_backend *text_backend)
>  	if (strcmp(text_backend->input_method.path, "") == 0)
>  		return;
>  
> -	if (text_backend->input_method.process.pid != 0)
> -		return;
> -
>  	text_backend->input_method.client =
> -		weston_client_launch(text_backend->compositor,
> -				     &text_backend->input_method.process,
> -				     text_backend->input_method.path,
> -				     handle_input_method_sigchld);
> +		weston_client_start(text_backend->compositor,
> +				    text_backend->input_method.path);
>  
> -	if (!text_backend->input_method.client)
> +	if (!text_backend->input_method.client) {
>  		weston_log("not able to start %s\n",
>  			   text_backend->input_method.path);
> +		return;
> +	}
> +
> +	text_backend->client_listener.notify = input_method_client_notifier;
> +	wl_client_add_destroy_listener(text_backend->input_method.client,
> +				       &text_backend->client_listener);
>  }
>  
>  static void
> @@ -1028,8 +1036,11 @@ text_backend_configuration(struct text_backend *text_backend)
>  WL_EXPORT void
>  text_backend_destroy(struct text_backend *text_backend)
>  {
> -	if (text_backend->input_method.client)
> +	if (text_backend->input_method.client) {
> +		/* disable respawn */
> +		wl_list_remove(&text_backend->client_listener.link);
>  		wl_client_destroy(text_backend->input_method.client);
> +	}
>  
>  	free(text_backend->input_method.path);
>  	free(text_backend);
> -- 
> 2.1.4
> 
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