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Internals of rattler-build#

Making Packages Relocatable with Rattler-Build#

Often, the most challenging aspect of building a package using rattler-build is making it relocatable. A relocatable package can be installed into any prefix, allowing it to be used outside the environment in which it was built. This is in contrast to a non-relocatable package, which can only be utilized within its original build environment.

rattler-build automatically performs the following actions to make packages relocatable:

  1. Binary object file conversion: Binary object files are converted to use relative paths using install_name_tool on macOS and patchelf on Linux. This uses $ORIGIN for elf files on Linux and @loader_path for Mach-O files on macOS to make the rpath relative to the executable / shared library.
  2. Text file prefix registration: Any text file without NULL bytes containing the placeholder prefix have the registered prefix replaced with the install prefix.
  3. Binary file prefix detection and registration: Binary files containing the build prefix can be automatically registered. The registered files will have their build prefix replaced with the install prefix at install time. This works by padding the install prefix with null terminators, such that the length of the binary file remains the same. The build prefix must be long enough to accommodate any reasonable installation prefix. On macOS and Linux, rattler-build pads the build prefix to 255 characters by appending _placehold to the end of the build directory name.