[PATCH weston] refactor configuration API of fbdev-backend

Benoit Gschwind gschwind at gnu-log.net
Tue Apr 26 19:24:43 UTC 2016


Hello pq,

Thanks for your review.

I did a patch update.

About the initialization and memory leak of .device options, as we
discussed on IRC, the current code is valid :) because of the following
lines :

+	if (!config.device)
+		config.device = strdup("/dev/fb0");

Thus I guess I do not need to fix it :)

If there is some other things to improve this let me know :)

Best regards.

Le 26/04/2016 10:49, Pekka Paalanen a écrit :
> On Sat, 23 Apr 2016 11:14:27 +0200
> Benoit Gschwind <gschwind at gnu-log.net> wrote:
> 
>> Implement a "well" defined API to configure the fbdev backend.
>> Following according to discution about libweston API
>> ---
>> v0:
>>   - First proposal.
>>   
>>  src/compositor-fbdev.c | 45 +++++++++++++++++++++++----------------------
>>  src/compositor-fbdev.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>>  src/main.c             | 33 +++++++++++++++++++++++++++++++--
>>  3 files changed, 103 insertions(+), 24 deletions(-)
>>  create mode 100644 src/compositor-fbdev.h
> 
> Hi Benoit,
> 
> this patch is missing all Makefile.am changes. That means it fails distcheck with
> ../../src/main.c:50:30: fatal error: compositor-fbdev.h: No such file or directory
>  #include "compositor-fbdev.h"
> 
> You also forgot Signed-off-by.
> 
>>
>> diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
>> index 19c5e3b..d0597a6 100644
>> --- a/src/compositor-fbdev.c
>> +++ b/src/compositor-fbdev.c
>> @@ -44,6 +44,7 @@
>>  
>>  #include "shared/helpers.h"
>>  #include "compositor.h"
>> +#include "compositor-fbdev.h"
>>  #include "launcher-util.h"
>>  #include "pixman-renderer.h"
>>  #include "libinput-seat.h"
>> @@ -93,12 +94,6 @@ struct fbdev_output {
>>  	uint8_t depth;
>>  };
>>  
>> -struct fbdev_parameters {
>> -	int tty;
>> -	char *device;
>> -	int use_gl;
>> -};
>> -
>>  struct gl_renderer_interface *gl_renderer;
>>  
>>  static const char default_seat[] = "seat0";
>> @@ -744,7 +739,7 @@ fbdev_restore(struct weston_compositor *compositor)
>>  static struct fbdev_backend *
>>  fbdev_backend_create(struct weston_compositor *compositor, int *argc, char *argv[],
>>                       struct weston_config *config,
>> -                     struct fbdev_parameters *param)
>> +                     struct weston_fbdev_backend_config *param)
>>  {
>>  	struct fbdev_backend *backend;
>>  	const char *seat_id = default_seat;
>> @@ -827,29 +822,35 @@ out_compositor:
>>  	return NULL;
>>  }
>>  
>> +static void
>> +config_init_to_defaults(struct weston_fbdev_backend_config *config)
>> +{
>> +	/* TODO: Ideally, available frame buffers should be enumerated using
>> +	 * udev, rather than passing a device node in as a parameter. */
>> +	config->tty = 0; /* default to current tty */
>> +	config->device = "/dev/fb0"; /* default frame buffer */
>> +	config->use_gl = 0;
>> +}
>> +
>>  WL_EXPORT int
>>  backend_init(struct weston_compositor *compositor, int *argc, char *argv[],
>> -	     struct weston_config *config,
>> +	     struct weston_config *wc,
>>  	     struct weston_backend_config *config_base)
>>  {
>>  	struct fbdev_backend *b;
>> -	/* TODO: Ideally, available frame buffers should be enumerated using
>> -	 * udev, rather than passing a device node in as a parameter. */
>> -	struct fbdev_parameters param = {
>> -		.tty = 0, /* default to current tty */
>> -		.device = "/dev/fb0", /* default frame buffer */
>> -		.use_gl = 0,
>> -	};
>> +	struct weston_fbdev_backend_config config = {{ 0, }};
>>  
>> -	const struct weston_option fbdev_options[] = {
>> -		{ WESTON_OPTION_INTEGER, "tty", 0, &param.tty },
>> -		{ WESTON_OPTION_STRING, "device", 0, &param.device },
>> -		{ WESTON_OPTION_BOOLEAN, "use-gl", 0, &param.use_gl },
>> -	};
>> +	if (config_base == NULL ||
>> +	    config_base->struct_version != WESTON_FBDEV_BACKEND_CONFIG_VERSION ||
>> +	    config_base->struct_size > sizeof(struct weston_fbdev_backend_config)) {
>> +		weston_log("fbdev backend config structure is invalid\n");
>> +		return -1;
>> +	}
>>  
>> -	parse_options(fbdev_options, ARRAY_LENGTH(fbdev_options), argc, argv);
>> +	config_init_to_defaults(&config);
>> +	memcpy(&config, config_base, config_base->struct_size);
>>  
>> -	b = fbdev_backend_create(compositor, argc, argv, config, &param);
>> +	b = fbdev_backend_create(compositor, argc, argv, wc, &config);
> 
> There is a small issue with config.device. It is ok for
> config_init_to_defaults() to use a statically allocated const string
> for it, because the pointer gets overwritten with a pointer from
> main.c. However, fbdev_output_create() is storing the pointer instead
> of calling strdup(). When main.c after init frees the pointer,
> fbdev_output::device will contain a stale pointer.
> 
> Could you send a preparation patch that makes fbdev_output_create() use
> strdup() for the device string, please?
> 
> I think it might have leaked the device string allocated by
> parse_options() before your patch.
> 
>>  	if (b == NULL)
>>  		return -1;
>>  	return 0;
>> diff --git a/src/compositor-fbdev.h b/src/compositor-fbdev.h
>> new file mode 100644
>> index 0000000..48bd269
>> --- /dev/null
>> +++ b/src/compositor-fbdev.h
>> @@ -0,0 +1,49 @@
>> +/*
>> + * Copyright © 2016 Benoit Gschwind
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining
>> + * a copy of this software and associated documentation files (the
>> + * "Software"), to deal in the Software without restriction, including
>> + * without limitation the rights to use, copy, modify, merge, publish,
>> + * distribute, sublicense, and/or sell copies of the Software, and to
>> + * permit persons to whom the Software is furnished to do so, subject to
>> + * the following conditions:
>> + *
>> + * The above copyright notice and this permission notice (including the
>> + * next paragraph) shall be included in all copies or substantial
>> + * portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
>> + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
>> + * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
>> + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
>> + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
>> + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
>> + * SOFTWARE.
>> + */
>> +
>> +#ifndef WESTON_COMPOSITOR_FBDEV_H
>> +#define WESTON_COMPOSITOR_FBDEV_H
>> +
>> +#ifdef  __cplusplus
>> +extern "C" {
>> +#endif
>> +
>> +#include "compositor.h"
>> +
>> +#define WESTON_FBDEV_BACKEND_CONFIG_VERSION 1
>> +
>> +struct weston_fbdev_backend_config {
>> +	struct weston_backend_config base;
>> +
>> +	int tty;
>> +	char *device;
>> +	int use_gl;
>> +};
>> +
>> +#ifdef  __cplusplus
>> +}
>> +#endif
>> +
>> +#endif /* WESTON_COMPOSITOR_FBDEV_H */
>> diff --git a/src/main.c b/src/main.c
>> index fc97dd8..7257059 100644
>> --- a/src/main.c
>> +++ b/src/main.c
>> @@ -48,6 +48,7 @@
>>  #include "version.h"
>>  
>>  #include "compositor-headless.h"
>> +#include "compositor-fbdev.h"
>>  
>>  static struct wl_list child_process_list;
>>  static struct weston_compositor *segv_compositor;
>> @@ -718,11 +719,41 @@ load_headless_backend(struct weston_compositor *c, char const * backend,
>>  }
>>  
>>  static int
>> +load_fbdev_backend(struct weston_compositor *c, char const * backend,
>> +		      int *argc, char **argv, struct weston_config *wc)
>> +{
>> +	struct weston_fbdev_backend_config config = {{ 0, }};
>> +	int ret = 0;
>> +
>> +	const struct weston_option fbdev_options[] = {
>> +		{ WESTON_OPTION_INTEGER, "tty", 0, &config.tty },
>> +		{ WESTON_OPTION_STRING, "device", 0, &config.device },
>> +		{ WESTON_OPTION_BOOLEAN, "use-gl", 0, &config.use_gl },
>> +	};
>> +
>> +	parse_options(fbdev_options, ARRAY_LENGTH(fbdev_options), argc, argv);
> 
> Looks like you are missing to set the defaults for the command line
> options. They are all just zero/NULL here.
> 
> Note, that the config_init_to_defaults() in compositor-fbdev.c applies
> only to the fields that main.c is not setting, but currently as this is
> the first revision of weston_fbdev_backend_config, all fields are set by
> main.c always.
> 
> Did this run at all?
> 
>> +
>> +	if(!config.device)
> 
> Use a space after a keyword.
> 
>> +		config.device = strdup("/dev/fb0");
>> +
>> +	config.base.struct_version = WESTON_FBDEV_BACKEND_CONFIG_VERSION;
>> +	config.base.struct_size = sizeof(struct weston_fbdev_backend_config);
>> +
>> +	/* load the actual wayland backend and configure it */
>> +	ret = load_backend_new(c, backend, &config.base);
>> +
>> +	free(config.device);
>> +	return ret;
>> +}
>> +
>> +static int
>>  load_backend(struct weston_compositor *compositor, const char *backend,
>>  	     int *argc, char **argv, struct weston_config *config)
>>  {
>>  	if (strstr(backend, "headless-backend.so"))
>>  		return load_headless_backend(compositor, backend, argc, argv, config);
>> +	else if (strstr(backend, "fbdev-backend.so"))
>> +		return load_fbdev_backend(compositor, backend, argc, argv, config);
>>  #if 0
>>  	else if (strstr(backend, "drm-backend.so"))
>>  		return load_drm_backend(compositor, backend, argc, argv, config);
>> @@ -730,8 +761,6 @@ load_backend(struct weston_compositor *compositor, const char *backend,
>>  		return load_wayland_backend(compositor, backend, argc, argv, config);
>>  	else if (strstr(backend, "x11-backend.so"))
>>  		return load_x11_backend(compositor, backend, argc, argv, config);
>> -	else if (strstr(backend, "fbdev-backend.so"))
>> -		return load_fbdev_backend(compositor, backend, argc, argv, config);
>>  	else if (strstr(backend, "rpi-backend.so"))
>>  		return load_rpi_backend(compositor, backend, argc, argv, config);
>>  	else if (strstr(backend, "rdp-backend.so"))
> 
> Otherwise this looks fine.
> 
> 
> Thanks,
> pq
> 


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