Can I change 'rpath' in an already compiled binary?

linux linker elf
Rich Homolka picture Rich Homolka · Dec 7, 2012 · Viewed 61.1k times · Source

I have an old executable that's scheduled for the scrap heap, but it's not there yet. It relies on some libs that have been removed from my environment, but I have some stub libs someplace where it works fine. Id like to point this executable to these stub libs. Yes, i could set LD_LIBRARY_PATH, but this executable is called from many scripts, and many users and I'd love to fix it in one spot.

I don't have source for this, and would be hard to get it. I was thinking - can I edit this file, using an ELF aware editor, and add a simple PATH to rpath to have it hit the new libs? Is this possible, or once you create an ELF binary, you fix things to locations and they can't be moved?

Answer

user7610 picture user7610 · Dec 2, 2013

There is a more universal tool than chrpath called patchelf. It was originally created for use in making packages for Nix and NixOS (packaging system and a GNU/Linux distribution).

In case there is no rpath in a binary (here called rdsamp), chrpath fails:

chrpath -r '$ORIGIN/../lib64' rdsamp 
rdsamp: no rpath or runpath tag found.

On the other hand,

patchelf --set-rpath '$ORIGIN/../lib64' rdsamp

succeeds just fine.

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