patchelf/README.md

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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:
```console
$ patchelf --set-interpreter /lib/my-ld-linux.so.2 my-program
```
* Change the `RPATH` of executables and libraries:
```console
$ patchelf --set-rpath /opt/my-libs/lib:/other-libs my-program
```
* Shrink the `RPATH` of executables and libraries:
```console
$ 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:
```console
$ patchelf --shrink-rpath --allowed-rpath-prefixes /usr/lib:/foo/lib my-program
```
* Remove declared dependencies on dynamic libraries (`DT_NEEDED`
entries):
```console
$ 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`):
```console
$ 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`):
```console
$ patchelf --replace-needed liboriginal.so.1 libreplacement.so.1 my-program
```
This option can be give multiple times.
* Change `SONAME` of a dynamic library:
```console
$ patchelf --set-soname libnewname.so.3.4.5 path/to/libmylibrary.so.1.2.3
```
## Compiling and Testing
### Via Autotools
```console
./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 <edolstra@gmail.com>.
## 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/>.