[PATCH libinput] doc: add instructions for handling SELinux denials

[Eric Engestrom]

On Tuesday, 2017-06-20 12:45:15 +1000, Peter Hutterer wrote:
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>  doc/building.dox | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/doc/building.dox b/doc/building.dox
> index 5ce21463..25594da8 100644
> --- a/doc/building.dox
> +++ b/doc/building.dox
> @@ -102,6 +102,33 @@ overwriting manually installed files.
>  <li><b>Arch</b>: ```sudo packman -S libinput```</li>
>  </ul>
>  
> + at subsection building_selinux SELinux adjustments
> +
> +On systems with SELinux, overwriting the distribution-provided package with
> +a manually built libinput may cause SELinux denials. This usually manifests
> +when gdm does not start because it is denied access to libinput. The journal
> +shows a log message in the form of:
> +
> +<pre>
> +May 25 15:28:42 localhost.localdomain audit[23268]: AVC avc:  denied  { execute } for  pid=23268 comm="gnome-shell" path="/usr/lib64/libinput.so.10.12.2" dev="dm-0" ino=1709093 scontext=system_u:system_r:xdm_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=0
> +May 25 15:28:42 localhost.localdomain org.gnome.Shell.desktop[23270]: /usr/bin/gnome-shell: error while loading shared libraries: libinput.so.10: failed to map segment from shared object
> +</pre>
> +
> +The summary of this error message is that gdm's gnome-shell runs in the
> +```system_u:system_r:xdm_t``` context but libinput is installed with the
> +context ```unconfined_u:object_r:user_home_t```.
> +
> +To avoid this issue, restore the SELinux context for any system files.
> +
> +<pre>
> +$> sudo restorecon /usr/lib/libinput.so.*
> +$> sudo restorecon /usr/lib64/libinput.so.*
> +</pre>
> +
> +Pick whichever one is your libdir.

You don't need this note if you give that command instead :)

$> sudo restorecon /usr/lib*/libinput.so.*

Reviewed-by: Eric Engestrom <eric.engestrom at imgtec.com>

> +
> +This issue is tracked in https://github.com/mesonbuild/meson/issues/1967.
> +
>  @subsection building_dependencies Build dependencies
>  
>  libinput has a few build-time dependencies that must be installed prior to
> -- 
> 2.13.0
>