libsys: Implement safe aux vec initialization
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Authored by aokblast on Mar 17 2026, 6:40 AM.

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Reviewers

dim
kib
jrtc27

Summary

In llvm sanitizer, we directly refenrece the aux vector by using weak
symbol since some of the aux info does not appeared in elf_aux_info.
However, since the elf_aux_vector is lazy initialzed, it is possible
that elf_aux_vector will be NULL if the sanitizer initialize early
enough. Therefore, we provide a function to allow external user of
__elf_aux_vector to be properly initilized.

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rG FreeBSD src repository

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Build Status

Buildable 71446
Build 68329: arc lint + arc unit

Event Timeline

aokblast created this revision.Mar 17 2026, 6:40 AM

Herald added a subscriber: imp. · View Herald TranscriptMar 17 2026, 6:40 AM

aokblast requested review of this revision.Mar 17 2026, 6:40 AM

Harbormaster completed remote builds in B71446: Diff 173787.Mar 17 2026, 6:40 AM

Reference user: https://github.com/llvm/llvm-project/pull/186961
Raw __elf_aux_vec usage: https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp#L72

aokblast added a reviewer: dim.Mar 22 2026, 7:27 AM

aokblast added reviewers: kib, jrtc27.Fri, Jun 19, 2:00 PM

kib added inline comments.Fri, Jun 19, 3:30 PM

lib/libsys/Symbol.map
7	why do you need the prefixed private symbol? In fact, I think that it is ok but should have two underscores. And I prefer that we do not export any stable interface for this, i.e. remove the libsys_elf_aux_vec_addr from the version as well as the alias. Use __libsys_.. in the santitizer, which already knows to much about the C runtime internals anyway. Also remove the proto from the public header.