Re: [gentoo-alt] Binary-only distributions on linux

[Johan Hattne]

On 04/23/10 03:02, Fabian Groffen wrote:
> On 22-04-2010 20:55:58 -0500, Johan Hattne wrote:
>> As far as I can see, setting the rpath is one way to solve the problem,
>> and I've been toying around with patchelf to accomplish that (chrpath
>> won't work, because it doesn't allow rpaths to grow).  To my mind, the
>
> I'd like to add it to the tree when I've got time to make an ebuild for
> it.

Here's a start (lines broken courtesy of mailer).  "ebuild test" works
for me.

EAPI="3"

DESCRIPTION="A small utility to modify the dynamic linker and RPATH of
ELF executables"
HOMEPAGE="http://nixos.org/patchelf.html"
SRC_URI="http://hydra.nixos.org/build/114505/download/2/${PN}-${PV}.tar.bz2"

KEYWORDS="~x86-linux"
LICENSE="GPL-3"
SLOT="0"

src_configure() {
        econf --docdir="${EROOT}/usr/share/doc/${PN}-${PV}" \
        || die "configure failed"
}

src_install() {
        emake install DESTDIR="${D}" || die "make install failed"
}

From what I understand, it doesn't work on Solaris (why?), so Linux only.

>> process is conceptually similar to the "shebang prefixing" that happens
>> for shell scripts, so I'm wondering whether it would make sense to
>> implement it in a similar fashion, e.g.
>>
>>   for each ELF file {
>>     prepend ${EPREFIX} to each rpath element
>>     prepend ${EPREFIX}/lib:${EPREFIX}/usr/lib to rpath
>>   }
>>
>> somewhere in portage.  At least this allowed me to use icc to compile a
>> 32 bit helloworld using an x86-prefix on both x86 and amd64.
>
> Do you have an idea how to automagically select the correct ELF files?
> Most already contain the required paths of course.  I don't quickly see
> how we can pick the right ones out there to "fix", but perhaps that's
> possible.  Otherwise, maybe a function in prefix.eclass that does the
> job somehow?

Not sure which "correct" ELF files you mean: for now I just scanned the
whole image-directory for ELF files and fixed all of them up in a ad hoc
sort of way.  The assumption is that if there's no rpath, then
"${EPREFIX}/lib:${EPREFIX}/usr/lib" is probably reasonable.  If there is
an rpath "/A:/B", then
"${EPREFIX}/lib:${EPREFIX}/usr/lib:${EPREFIX}/A:${EPREFIX}/B" may be OK.
 But no, I didn't actually check whether the fixed rpaths can be used to
resolve dynamic linking.  And I haven't even thought about the
possibility that there may be ELF files which shouldn't have their rpath
"fixed".

This may very well be stupid in ways I haven't yet realised--I'm still
playing around with it.  But since I think that the binary-only ebuilds
should make it into prefix sooner (or later), I figure this is the place
to bring it up.

// Cheers; Johan