Bug 228934 - objcopy (from elftoolchain) does not set ELF OS/ABI field for binary->ELF conversion
Summary: objcopy (from elftoolchain) does not set ELF OS/ABI field for binary->ELF con...
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: bin (show other bugs)
Version: CURRENT
Hardware: Any Any
: --- Affects Only Me
Assignee: freebsd-bugs mailing list
Depends on:
Blocks: 231027
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Reported: 2018-06-12 13:24 UTC by Ed Maste
Modified: 2018-08-31 20:18 UTC (History)
0 users

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Description Ed Maste freebsd_committer 2018-06-12 13:24:22 UTC
One of the steps in building the amd64 64-bit linuxulator vdso is:
> objcopy --input-target binary --output-target elf64-x86-64-freebsd -S -g --binary-architecture i386:x86-64 linux_locore.o linux_vdso.so

This should set the ELF header OS/ABI field to FreeBSD. GNU objcopy does; ELF Tool Chain objcopy/elfcopy sets it to none/SYSV. With --output-target elf64-x86-64 GNU objcopy sets it to none/SYSV.

(Using --output-target elf64-x86-64-freebsd is actually a bug in the Linuxulator Makefile: the vdso is in fact supposed to be a Linux shared object, which is a separate issue to be fixed.)
Comment 1 commit-hook freebsd_committer 2018-06-12 13:32:48 UTC
A commit references this bug:

Author: emaste
Date: Tue Jun 12 13:32:42 UTC 2018
New revision: 334998
URL: https://svnweb.freebsd.org/changeset/base/334998

  linux64: use linux output target for linux_vdso.so

  linux_vdso.so provides the vdso for the linuxulator's amd64 target and
  is mapped into a Linux binary's address space.  Thus it should be a
  Linux-style .so, which has the ELF OS/ABI unset.

  It turns out that ELF Tool Chain elfcopy/objcopy also has a bug where
  the OS/ABI field is unset, regardless of the specified --output-target,
  so this change is a no-op with the default in-tree toolchain.  This is a
  real fix when using external binutils, and the ELF Tool Chain bug will
  be fixed in the future.

  PR:		228934
  Sponsored by:	Turing Robotic Industries