mybcbin / termux-elf-cleaner

Utility to remove unused ELF sections causing warnings.

termux-elf-cleaner

Utility for Android ELF files to remove unused parts that the linker warns about.

Description

When loading ELF files, the Android linker warns about unsupported dynamic section entries with warnings such as:

WARNING: linker: /data/data/org.kost.nmap.android.networkmapper/bin/nmap: unused DT entry: type 0x6ffffffe arg 0x8a7d4
WARNING: linker: /data/data/org.kost.nmap.android.networkmapper/bin/nmap: unused DT entry: type 0x6fffffff arg 0x3

This utility strips away the following dynamic section entries:

• DT_RPATH - not supported in any Android version.
• DT_GNU_HASH - supported from Android 6.0.
• DT_RUNPATH - supported from Android 7.0.
• DT_VERDEF - supported from Android 6.0.
• DT_VERDEFNUM - supported from Android 6.0.
• DT_VERNEEDED - supported from Android 6.0.
• DT_VERNEEDNUM - supported from Android 6.0.
• DT_VERSYM - supported from Android 6.0.
• DT_AARCH64_BTI_PLT - supported from Android 12.
• DT_AARCH64_PAC_PLT - supported from Android 12.
• DT_AARCH64_VARIANT_PCS - supported from Android 12.

It also removes the three ELF sections of type:

• SHT_GNU_verdef
• SHT_GNU_verneed
• SHT_GNU_versym

And makes sure that the alignment of a TLS segment is at least 32 (for 32bit arches) or 64 (for 64bit arches), to prevent errors similar to:

error: "valgrind": executable's TLS segment is underaligned: alignment is 8, needs to be at least 64 for ARM64 Bionic

Usage

Usage: termux-elf-cleaner [OPTION-OR-FILENAME]...

Processes ELF files to remove unsupported section types and
dynamic section entries which the Android linker warns about.

Options:

--api-level NN        choose target api level, i.e. 21, 24, ..
--dry-run             print info but but do not remove entries
--quiet               do not print info about removed entries
--help                display this help and exit
--version             output version information and exit

License

SPDX-License-Identifier: GPL-3.0-or-later

See also

• Bionic's related docs