bluepeople1/patchelf

A small utility to modify the dynamic linker and RPATH of ELF executables

PatchELF is a simple utility for modifying existing ELF executables and libraries. In particular, it can do the following:

• Change the dynamic loader ("ELF interpreter") of executables:

  $ patchelf --set-interpreter /lib/my-ld-linux.so.2 my-program

• Change the RPATH of executables and libraries:

  $ patchelf --set-rpath /opt/my-libs/lib:/other-libs my-program

• Shrink the RPATH of executables and libraries:

  $ patchelf --shrink-rpath my-program

  This removes from the RPATH all directories that do not contain a library referenced by DT_NEEDED fields of the executable or library. For instance, if an executable references one library libfoo.so, has an RPATH /lib:/usr/lib:/foo/lib, and libfoo.so can only be found in /foo/lib, then the new RPATH will be /foo/lib.

  In addition, the --allowed-rpath-prefixes option can be used for further rpath tuning. For instance, if an executable has an RPATH /tmp/build-foo/.libs:/foo/lib, it is probably desirable to keep the /foo/lib reference instead of the /tmp entry. To accomplish that, use:

  $ patchelf --shrink-rpath --allowed-rpath-prefixes /usr/lib:/foo/lib my-program

• Remove declared dependencies on dynamic libraries (DT_NEEDED entries):

  $ patchelf --remove-needed libfoo.so.1 my-program

  This option can be given multiple times.

• Add a declared dependency on a dynamic library (DT_NEEDED):

  $ patchelf --add-needed libfoo.so.1 my-program

  This option can be give multiple times.

• Replace a declared dependency on a dynamic library with another one (DT_NEEDED):

  $ patchelf --replace-needed liboriginal.so.1 libreplacement.so.1 my-program

  This option can be give multiple times.

• Change SONAME of a dynamic library:

  $ patchelf --set-soname libnewname.so.3.4.5 path/to/libmylibrary.so.1.2.3

Compiling and Testing

Via Autotools

./bootstrap.sh
./configure
make
make check
sudo make install

Via Nix

You can build with Nix in several ways.

1. Building via nix build will produce the result in ./result/bin/patchelf. If you would like to build patchelf with musl try nix build .#patchelf-musl

2. You can launch a development environment with nix develop and follow the autotools steps above. If you would like to develop with musl try nix develop .#musl

Author

Copyright 2004-2019 Eelco Dolstra [email protected].

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.