Portable binaries

The LD_PRELOAD option

The well-known LD_PRELOAD trick can be used to provide somewhat portable DICOMautomaton binaries for Linux systems. Binaries from the system-installed or locally-built DICOMautomaton will be automatically gathered by building and then invoking:

 $>  ./scripts/dump_portable_dcma_bundle.sh /tmp/portable_dcma/

If successful, the portable outputs will be dumped to /tmp/portable_dcma/. A convenience script that performs the preload trick and forwards all user arguments is portable_dcma.

Note that this trick works only on Linux systems, and a similar Linux system must be used to generate the binaries. The interactive Debian Docker container will likely suffice. Additionally this technique only provides the dicomautomaton_dispatcher binary. All shared libraries needed to run it are bundled, including glibc and some other intrinsic libraries in case the host and target glibc differ. If the patchelf program is available, the binary can be patched to use the bundled ld-linux.so interpreter and glibc using the included adjusting_dcma script, otherwise the system interpreter will be used. If patchelf is not available it is best to remove ld-linux, libm, and libc from the bundle and rely fully on the target glibc. Mixing and matching bits of different glibc installations will almost certainly result in segmentation faults or silent failures so it is not recommended in any circumstances. Also note that compilation arguments and architecture-specific tunings will likely ruin portability.

Alternatively, a third wrapper script (emulate_dcma) uses qemu-x86_64 to emulate a 64 bit x86 system and preload bundled libraries. This script may work when the native LD_PRELOAD trick fails, but emulation may be slow. The cpu can be emulated, so it may be possible to support architecture-specific tunings this way.

Portability, validity of the program, and full functionality are NOT guaranteed using either script! They should all be considered experimental. The preload trick is best run in a controlled environment, and targetting the same controlled environment and architecture. This method of distributing DICOMautomaton is not officially supported, but can simplify distributing custom builds in some situations.