[Bug dynamic-link/17251] New: RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[Bug dynamic-link/17251] New: RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[bpshacklett at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

            Bug ID: 17251
           Summary: RPATH of shared libraries doesn't follow symlinks for
                    $ORIGIN
           Product: glibc
           Version: 2.19
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dynamic-link
          Assignee: unassigned at sourceware dot org
          Reporter: bpshacklett at gmail dot com

t


I'm not 100% sure if this a bug or intended behavior, I can't find any evidence
for either argument.

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[bpshacklett at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

--- Comment #1 from Brennan Shacklett <bpshacklett at gmail dot com> ---
Oops, sorry for the empty description, firefox decided to submit the form when
I hit enter.
The issue is that if a shared library has $ORIGIN in its RPATH, $ORIGIN is not
calculated as the real path of the library.

This can easily be shown with two shared libraries and a symlink:

libone.so and libtwo.so are both in a directory named ~/lib
libone.so needs libtwo.so, and has an RPATH of "$ORIGIN" so libtwo.so can be
found.
If I cd into ~/lib and run ldd on libone.so, libtwo.so is found.
If I create a symlink from ~/libone.so to ~/lib/libone.so, and run ldd on the
symlink at ~/libone.so, libtwo.so can no longer be found because $ORIGIN is not
calculated as ~ rather than ~/lib

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[bpshacklett at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

--- Comment #2 from Brennan Shacklett <bpshacklett at gmail dot com> ---
s/is not calculated/is calculated/ in the last sentence.

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[bpshacklett at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

--- Comment #3 from Brennan Shacklett <bpshacklett at gmail dot com> ---
Created attachment 7744
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7744&action=edit
Patch to switch $ORIGIN to be calculated based on absolute path

This patch fixes the behavior for me, I'll also post it to the mailing list
with an explanation.

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com

--- Comment #4 from Florian Weimer <fweimer at redhat dot com> ---
I'm not sure if you can use __realpath from the dynamic linker.  And PATH_MAX
could be too small; the __realpath function with a non-NULL second argument is
basically broken.

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[bpshacklett at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

--- Comment #5 from Brennan Shacklett <bpshacklett at gmail dot com> ---
Well I defined __realpath in dl-realpath.c and included that into
rtld-routines, doesn't that allow the linker to use it?
I'm not sure what you mean about __realpath being broken with a non null 2nd
argument, the version which I defined in dl-realpath doesn't even handle a NULL
second argument (I didn't think it was necessary). Are you saying I should
rewrite the dl-realpath version to handle that NULL and dynamically allocate
its own memory?

There is a more detailed explanation in my mailing list post here:
https://sourceware.org/ml/libc-alpha/2014-08/msg00160.html if you want more
details.

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[Bug dynamic-link/17251] RPATH of shared libraries doesn't follow symlinks for $ORIGIN

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=17251

--- Comment #6 from Florian Weimer <fweimer at redhat dot com> ---
(In reply to Brennan Shacklett from comment #5)
> Well I defined __realpath in dl-realpath.c and included that into
> rtld-routines, doesn't that allow the linker to use it?

Ah, I missed the reimplementation.  I'll post further questions to the mailing
list.

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