[Mesa-dev] [PATCH] anv: Give the installed intel_icd.json file an absolute path

[Nicholas Miell]

On 08/23/2016 02:07 AM, Emil Velikov wrote:
> Skimmed through the discussion and I'm not sure the above will be enough.
>
> Since the user is free to place json files in $HOME/.local ... this
> implies that they may _not_ have access to /usr or /etc. Thus as they
> install the file (to say $HOME/foo/lib) the Vulkan loader will not be
> able to pick it up.

Why not?

Stick the 32-bit library in $HOME/foo/lib, the 64-bit library in 
$HOME/foo/lib64, set library_path to "/home/emil/foo/$LIB/lib_mygpu.so" 
in the $HOME/.local/share/vulkan/icd.d/mygpu.json file, and it should 
work, right?

> In theory one should be able to have a varying .json (one with and one
> without the path) although the heuristics will be fragile due to the
> varying $LIB (like the case of Debian and derivatives) and $DESTDIR.
>
> So I see the following options:
>  - new configure option - have to agree with Dave, please don't.
> Furthermore we already have more than 50! of them.
>  - fold the "w or w/o full path" under and existing option
> (--enable-debug ?) - somewhat picky/fragile as well. Kind of OK for
> short term solution.
>  - use LD_LIBRARY_PATH - slightly annoying yet add once and forget
> about it. OK-ish short term solution.
>  - json update - the better long term solution imho.
>
> Json update:
>  - the same file _cannot_ be provided by multiple packages

RPM certainly allows this, as long as the packages that provide the file 
have the same name & version, different architectures, and the files are 
byte-identical. Sticking $LIB in the path instead of "lib" or "lib64" 
makes the files byte-identical.

>  - thus we should use differently named files, but we should not rely
> on the filename to determine arch/triple.
> There has been no such recommendations/restrictions about the name so
> starting now feels wrong.
>  - so let's bump "file_format_version" - 1.0.1 or 1.1.0 ?
>  - add ICD::arch tag and teach the loader to honour it. For json files
> missing it we'll assume a "can be used on this platform" behaviour.
>  - should we bother with the other parts of the triple or add it only
> as need arise ?
>
> With the above in place, one can have full path + filename for the
> mutlilib setups. Old loaders will just get an error upon dlopen of
> incompatible/wrong arch ICDs.
>
> How do the above short/long term solutions sound ?
>
> Thanks
> Emil
>