[PATCH weston] compositor-fbdev: make copy of the device string

[Quentin Glidic]

On 28/04/2016 16:08, Pekka Paalanen wrote:
> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
>
> Ensuring that the pointer to the device path stays valid gets harder and
> harder with migrating to the libweston-style config handling. Therefore,
> make a copy of the string, private to struct fbdev_output.
>
> Now the pointer passed in to fbdev_output_create() could be freed right
> after the call returns.
>
> Cc: Benoit Gschwind <gschwind at gnu-log.net>
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> ---
>  src/compositor-fbdev.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
> index 19c5e3b..e2f978b 100644
> --- a/src/compositor-fbdev.c
> +++ b/src/compositor-fbdev.c
> @@ -84,7 +84,7 @@ struct fbdev_output {
>  	struct wl_event_source *finish_frame_timer;
>
>  	/* Frame buffer details. */
> -	const char *device; /* ownership shared with fbdev_parameters */
> +	char *device;
>  	struct fbdev_screeninfo fb_info;
>  	void *fb; /* length is fb_info.buffer_length */
>
> @@ -470,7 +470,7 @@ fbdev_output_create(struct fbdev_backend *backend,
>  		return -1;
>
>  	output->backend = backend;
> -	output->device = device;
> +	output->device = strdup(device);
>
>  	/* Create the frame buffer. */
>  	fb_fd = fbdev_frame_buffer_open(output, device, &output->fb_info);
> @@ -554,6 +554,7 @@ out_hw_surface:
>  	weston_output_destroy(&output->base);
>  	fbdev_frame_buffer_destroy(output);
>  out_free:
> +	free(output->device);
>  	free(output);
>
>  	return -1;
> @@ -580,6 +581,7 @@ fbdev_output_destroy(struct weston_output *base)
>  	/* Remove the output. */
>  	weston_output_destroy(&output->base);
>
> +	free(output->device);
>  	free(output);
>  }
>
> @@ -607,7 +609,7 @@ fbdev_output_reenable(struct fbdev_backend *backend,
>  	struct fbdev_output *output = to_fbdev_output(base);
>  	struct fbdev_screeninfo new_screen_info;
>  	int fb_fd;
> -	const char *device;
> +	char *device;
>
>  	weston_log("Re-enabling fbdev output.\n");
>
> @@ -634,9 +636,10 @@ fbdev_output_reenable(struct fbdev_backend *backend,
>  		/* Remove and re-add the output so that resources depending on
>  		 * the frame buffer X/Y resolution (such as the shadow buffer)
>  		 * are re-initialised. */
> -		device = output->device;
> -		fbdev_output_destroy(base);
> +		device = strdup(output->device);
> +		fbdev_output_destroy(&output->base);
>  		fbdev_output_create(backend, device);
> +		free(device);

Maybe:
device = output->device;
output->device = NULL;
To avoid an strdup()?

>  		return 0;
>  	}
>


Another solution is to have fbdev_output_create() take ownership, so no 
free() in _reenable(), and move the strdup() to backend_create().

Whichever solution you pick (this patch, or one of the variants I 
suggested):

Reviewed-by: Quentin Glidic <sardemff7+git at sardemff7.net>

-- 

Quentin “Sardem FF7” Glidic