flake

patchelf

A tool for modifying ELF executables and libraries

README.md

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/.