NAME¶

patchelf - Modify ELF files

SYNOPSIS¶

patchelf OPTION FILE ...

DESCRIPTION¶

PatchELF is a simple utility for modifying existing ELF executables and libraries. It can change the dynamic loader ("ELF interpreter") of executables and change the RPATH of executables and libraries.

OPTIONS¶

The single option given operates on each FILE, editing in place.

Any option taking a string argument can also take a file by prefixing the argument with the @ symbol. See EXAMPLES

--page-size SIZE

Uses the given page size instead of the default.

--set-interpreter INTERPRETER

Change the dynamic loader ("ELF interpreter") of executable given to INTERPRETER.

--print-interpreter

Prints the ELF interpreter of the executable.

--print-os-abi

Prints the OS ABI of the executable (EI_OSABI field of an ELF file).

--set-os-abi ABI

Changes the OS ABI of the executable (EI_OSABI field of an ELF file). The ABI parameter is pretty flexible. For example, you can specify it as a "Linux", "linux", or even "lInUx" - all those names will set EI_OSABI field of the ELF header to the value "3", which corresponds to Linux OS ABI. The same applies to other ABI names - System V, FreeBSD, Solaris, etc.

--print-soname

Prints DT_SONAME entry of .dynamic section. Raises an error if DT_SONAME doesn't exist.

--set-soname SONAME

Sets DT_SONAME entry of a library to SONAME.

--set-rpath RUNPATH

Change the DT_RUNPATH of the executable or library to RUNPATH.

--add-rpath RUNPATH

Add RUNPATH to the existing DT_RUNPATH of the executable or library.

--remove-rpath

Removes the DT_RPATH or DT_RUNPATH entry of the executable or library.

--shrink-rpath

Remove from the DT_RUNPATH or DT_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".

--allowed-rpath-prefixes PREFIXES

Combined with the "--shrink-rpath" option, this 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.

--print-rpath

Prints the DT_RUNPATH or DT_RPATH for an executable or library.

--force-rpath

Forces the use of the obsolete DT_RPATH in the file instead of DT_RUNPATH. By default DT_RPATH is converted to DT_RUNPATH.

--add-needed LIBRARY

Adds a declared dependency on a dynamic library (DT_NEEDED). This option can be given multiple times.

--replace-needed LIB_ORIG LIB_NEW

Replaces a declared dependency on a dynamic library with another one (DT_NEEDED). This option can be given multiple times.

--remove-needed LIBRARY

Removes a declared dependency on LIBRARY (DT_NEEDED entry). This option can be given multiple times.

--print-needed

Prints all DT_NEEDED entries of the executable.

--no-default-lib

Marks the object so that the search for dependencies of this object will ignore any default library search paths.

--no-sort

Do not sort program headers or section headers. This is useful when debugging patchelf, because it makes it easier to read diffs of the output of "readelf -a".

--add-debug-tag

Adds DT_DEBUG tag to the .dynamic section if not yet present in an ELF object. A shared library (-shared) by default does not receive DT_DEBUG tag. This means that when a shared library has an entry point (so that it can be run as an executable), the debugger does not connect to it correctly and symbols are not resolved.

--print-execstack

Prints the state of the executable flag of the GNU_STACK program header, if present.

--clear-execstack

Clears the executable flag of the GNU_STACK program header, or adds a new header.

--set-execstack

Sets the executable flag of the GNU_STACK program header, or adds a new header.

--rename-dynamic-symbols NAME_MAP_FILE

Renames dynamic symbols. The name map file should contain lines with the old and the new name separated by spaces like this:

old_name new_name

Symbol names do not contain version specifier that are also shown in the output of the nm -D command from binutils. So instead of the name write@GLIBC_2.2.5 it is just write.

--output FILE

Set the output file name. If not specified, the input will be modified in place.

--debug

Prints details of the changes made to the input file.

--version

Shows the version of patchelf.

EXAMPLES¶

To use the contents on an external file as a parameter:

To change the RPATH of a binary. Note that $ORIGIN is a special symbol used by the loader, so must be quoted.

AUTHOR¶

Eelco Dolstra <e.dolstra@tudelft.nl>

SEE ALSO¶

elf(5), ld.so(8)