Appimage chdir'ing so relative paths doesn't work

[Dirk Hohndel]

On Tue, Jan 10, 2017 at 07:17:06PM +0100, probono wrote:
> 2017-01-08 19:30 GMT+01:00 Dirk Hohndel <dirk at hohndel.org>:
> >> On Jan 8, 2017, at 09:38, Anton Lundin <glance at acc.umu.se> wrote:
> >> Hi.
> >>
> >> I was about to test some stuff with the appimage-build and noted:
> >>
> >> strace -e chdir,open ./Subsurface-4.6-Beta-2-x86_64.AppImage testdata/ostc4.xml |& grep -E 'ostc|chdir'
> >> chdir("/tmp/.mount_xyn3Tx")             = 0
> >> chdir("usr")                            = 0
> >> open("testdata/ostc4.xml", O_RDONLY) = -1 ENOENT (No such file or directory)
> >>
> >>
> >> The chdir'ing might make sense in some case, but in this case it really
> >> doesn't.
> >
> > I think it needs to chdir in order to find its libraries, but I haven't looked
> > at this in enough detail.
> 
> The chdir is required only in cases in which binaries are not
> relocatable at runtime (i.e., "/usr" is hardcoded at compile time, for
> example for loading resources). If this is not the case (e.g., in the
> case of Subsurface), then we should get away without chdir'ing.

I've played around with this for a bit and it's actually quite a bit more
complicated than that. All the paths in AppRun.c are currently relative
paths - so this needs a bit of work that goes beyond "just don't do that
chdir".

/D