[VDPAU] [PATCH] Add VDPAU_DRIVER_PATH support

[Stephen Warren]

Emil Velikov wrote at Monday, March 10, 2014 2:13 PM:
> Allow the user to specify the location of the backend driver,
> via the VDPAU_DRIVER_PATH environment variable. This allows
> easier testing of VDPAU backends without the need to rebuild
> libvdpau.
> 
> Inspired by LIBGL_DRIVERS_PATH from mesa.

Acked-by: Stephen Warren <swarren at nvidia.com>

Just one question:

> diff --git a/include/vdpau/vdpau_x11.h b/include/vdpau/vdpau_x11.h

> +    if (geteuid() == getuid()) {
> +        /* don't allow setuid apps to use VDPAU_DRIVER_PATH */
> +        vdpau_driver_path = getenv("VDPAU_DRIVER_PATH");
> +        if (vdpau_driver_path &&
> +            snprintf(vdpau_driver_lib, sizeof(vdpau_driver_lib),
> +                     DRIVER_LIB_FORMAT, vdpau_driver_path, vdpau_driver) <
> +                sizeof(vdpau_driver_lib)) {
> +            _vdp_driver_dll = dlopen(vdpau_driver_lib, RTLD_NOW | RTLD_GLOBAL);

If the snprintf() there fails, we just ignore it...

> +    /* Fallback to VDPAU_MODULEDIR when VDPAU_DRIVER_PATH is not set,
> +     * or if we fail to create the driver path/dlopen the library. */
> +    if (!_vdp_driver_dll)
> +        if (snprintf(vdpau_driver_lib, sizeof(vdpau_driver_lib),
> +                     DRIVER_LIB_FORMAT, VDPAU_MODULEDIR, vdpau_driver) >=
> +                sizeof(vdpau_driver_lib)) {
> +            fprintf(stderr, "Failed to construct driver path: path too long\n");
> +            if (vdpau_driver_dri2) {
> +                XFree(vdpau_driver_dri2);
> +                vdpau_driver_dri2 = NULL;
> +            }
> +            _VDP_ERROR_BREAKPOINT();
> +            return VDP_STATUS_NO_IMPLEMENTATION;

... whereas here, we actively return an error.

Shouldn't those two paths be consistent; either each should return an error (probably best?), or perhaps both should print a warning message, and then the function should return an error at the end if (!_vdp_driver_dll)? 

-- 
nvpublic