Don't throw an error on missing DT_JMPREL section

[lukateras]

Excelsior JET (excelsiorjet.com) generates executables that don't have a section that corresponds to DT_JMPREL. It is impossible to patch such executables before this patch and after this patch these executables work fine (with interpreter set to NixOS dynamic linker).

[edolstra]

Where does DT_JMPREL's dyn->d_un.d_ptr point to for such executables?

[Mic92]

Where does DT_JMPREL's dyn->d_un.d_ptr point to for such executables?

I think it might stripped those sections and the entry in the dynamic section is invalid. Also see: #296

[Mic92]

@abelianring do you have an example binary that is also executable?

[Mic92]

excelsiorjet is end of life now. Please re-open if you have binaries that reproduce this issue.

[Dettorer]

I think I have one, I'm trying to package my university's horrendous video conferencing backend (https://sfc-unistra.classilio.com/Application/Via/Via.tar.gz) and I get the same error when patching the file libXXWS11308121.so:

patchelf: cannot find section corresponding to DT_JMPREL
Command failed: patchelf --set-interpreter /nix/store/9bh3986bpragfjmr32gay8p95k91q4gy-glibc-2.33-47/lib/ld-linux-x86-64.so.2 /nix/store/akv1srjggaa9ap2c6hxisx0gx2inqcpd-via-20210911/opt/sviesolutions/viascreensharing/rt/jetrt/libXXWS11308121.so
builder for '/nix/store/7155xd5ah2r4rah512azsqiib74h2w7w-via-20210911.drv' failed with exit code 1

[Mic92]

I downloaded the archive but there was no libXXWS11308121.so in it.

[Dettorer]

Its complete path in the archive is viascreensharing/rt/jetrt/libXXWS11308121.so

[Mic92]

I opened up #318

[Dettorer]

Thank you! I subscribed to the PR and I'll try to find some time to test it.

[Mic92]

I plan to do a release soon, depending on whether the other PR is tested it will be in or not.