[Mesa-dev] [PATCH 1/3] egl/x11_dri3: disable WL_bind_wayland_display for devices without render nodes

[Frank Binns]

On 20/06/16 12:05, Axel Davy wrote:
> Hi,
>
> The three patches make sense to me.
>
> Reviewed-by: Axel Davy <axel.davy at ens.fr>

Can someone push these patches for me?

Thanks
Frank

>
> On 17/06/2016 19:41, Frank Binns wrote :
>> Up until now, DRI3 was only used for devices that have render nodes, 
>> unless
>> overridden via an environment variable, with it falling back to DRI2 
>> otherwise.
>> This limitation was there in order to support WL_bind_wayland_display 
>> as it
>> requires client opened device node fds to be authenticated, which 
>> isn't possible
>> when using DRI3. This is an unfortunate compromise as DRI3 provides 
>> security
>> benefits over DRI2.
>>
>> Instead, allow DRI3 to be used for devices without render nodes but 
>> don't
>> advertise WL_bind_wayland_display in this case. Applications that 
>> need this
>> extension can still be run by disabling DRI3 support via the 
>> LIBGL_DRI3_DISABLE
>> environment variable.
>>
>> Signed-off-by: Frank Binns <frank.binns at imgtec.com>
>> ---
>>   src/egl/drivers/dri2/platform_x11.c      |  3 ++-
>>   src/egl/drivers/dri2/platform_x11_dri3.c | 33 
>> +++++---------------------------
>>   2 files changed, 7 insertions(+), 29 deletions(-)
>>
>> diff --git a/src/egl/drivers/dri2/platform_x11.c 
>> b/src/egl/drivers/dri2/platform_x11.c
>> index c0a4005..1b50889 100644
>> --- a/src/egl/drivers/dri2/platform_x11.c
>> +++ b/src/egl/drivers/dri2/platform_x11.c
>> @@ -1335,7 +1335,8 @@ dri2_initialize_x11_dri3(_EGLDriver *drv, 
>> _EGLDisplay *disp)
>>      disp->Extensions.EXT_buffer_age = EGL_TRUE;
>>     #ifdef HAVE_WAYLAND_PLATFORM
>> -   disp->Extensions.WL_bind_wayland_display = EGL_TRUE;
>> +   if (dri2_dpy->device_name)
>> +      disp->Extensions.WL_bind_wayland_display = EGL_TRUE;
>>   #endif
>>        if (dri2_dpy->conn) {
>> diff --git a/src/egl/drivers/dri2/platform_x11_dri3.c 
>> b/src/egl/drivers/dri2/platform_x11_dri3.c
>> index 9363a8a..b781987 100644
>> --- a/src/egl/drivers/dri2/platform_x11_dri3.c
>> +++ b/src/egl/drivers/dri2/platform_x11_dri3.c
>> @@ -437,29 +437,6 @@ struct dri2_egl_display_vtbl 
>> dri3_x11_display_vtbl = {
>>      .get_dri_drawable = dri3_get_dri_drawable,
>>   };
>>   -static char *
>> -dri3_get_device_name(int fd)
>> -{
>> -   char *ret = NULL;
>> -
>> -   ret = drmGetRenderDeviceNameFromFd(fd);
>> -   if (ret)
>> -      return ret;
>> -
>> -   /* For dri3, render node support is required for 
>> WL_bind_wayland_display.
>> -    * In order not to regress on older systems without kernel or libdrm
>> -    * support, fall back to dri2. User can override it with environment
>> -    * variable if they don't need to use that extension.
>> -    */
>> -   if (getenv("EGL_FORCE_DRI3") == NULL) {
>> -      _eglLog(_EGL_WARNING, "Render node support not available, 
>> falling back to dri2");
>> -      _eglLog(_EGL_WARNING, "If you want to force dri3, set 
>> EGL_FORCE_DRI3 environment variable");
>> -   } else
>> -      ret = loader_get_device_name_for_fd(fd);
>> -
>> -   return ret;
>> -}
>> -
>>   EGLBoolean
>>   dri3_x11_connect(struct dri2_egl_display *dri2_dpy)
>>   {
>> @@ -539,11 +516,11 @@ dri3_x11_connect(struct dri2_egl_display 
>> *dri2_dpy)
>>         return EGL_FALSE;
>>      }
>>   -   dri2_dpy->device_name = dri3_get_device_name(dri2_dpy->fd);
>> -   if (!dri2_dpy->device_name) {
>> -      close(dri2_dpy->fd);
>> -      return EGL_FALSE;
>> -   }
>> +   /* Only try to get a render device name since it's only needed for
>> +    * WL_bind_wayland_display and dri3 doesn't provide a mechanism for
>> +    * authenticating client opened device node fds. If this fails then
>> +    * don't advertise the extension. */
>> +   dri2_dpy->device_name = drmGetRenderDeviceNameFromFd(dri2_dpy->fd);
>>        return EGL_TRUE;
>>   }
>