On Sun, 30 Jul 2017 at 19:34:42 +0900, Benda Xu wrote:
> As far as I can see, the easiest relocations are those modifiable in a
> plain text, like configuration file, script shebang, etc. The medium
> ones are ELF, with which we have tools like patchelf and chrpath, etc.
> The most difficult part includes quite a few hidden path assumptions
> that can only be specified at build time, like the default GCC include
> dir. I don't know whether distributing binary packages can alleviate
> the barrier. Chances are many patches are needed to be carried to be
> able to override paths at run time.
Lots of packages hard-code paths at build time. This is often not
considered to be a bug.
Flatpak's approach to this is to use bind-mounts (in a new mount
namespace set up by bubblewrap) so that the "app" (the leaf package,
together with any libraries that are bundled with it) always appears
to be installed in --prefix=/app, which can safely be hard-coded into
binaries that are built as Flatpak apps.
Flatpak apps are normally recompiled from source with --prefix=/app,
but I don't think it's coincidental that /app is the same length as
/usr and can therefore be patched in with a binary editor as a last
resort :-)
S
