The gcompat project provides a glibc-compatible runtime environment for distributions that use musl libc.
It provides a compatibility library as well as a loader which injects the compatibility library. The loader
is installed where the glibc ELF interpreter (
/lib/ld-linux.so.2) would normally be, allowing for execution
of glibc programs to work in the same way as native musl programs.
In order to build correctly, the gcompat build system requires a few details about the host environment, both from the musl end, as well as the glibc end. These are:
||The location of the musl ELF interpreter.|
||The name of the glibc ELF interpreter that would be appropriate for your architecture.|
optional The location to install the libgcompat.so library to. Usually
optional The location to install the loader to. Usually
For example on x86_64 musl with x86_64 glibc compatibility, you would want to do:
$ make LINKER_PATH=/lib/ld-musl-x86_64.so.1 LOADER_NAME=ld-linux-x86-64.so.2 $ make LINKER_PATH=/lib/ld-musl-x86_64.so.1 LOADER_NAME=ld-linux-x86-64.so.2 install
DESTDIR environment variable is available for the convenience of packagers.
running programs under gcompat
Assuming everything is in the right place, the programs should just work. If they are not working, check the program's ELF interpreter entry, using scanelf(8) like so:
$ scanelf -i ~/glibcfile TYPE INTERP FILE ET_EXEC /lib64/ld-linux-x86-64.so.2 /home/kaniini/glibcfile
If the interpreter path is different than expected, use PatchELF or install a symlink to the interpreter.
making musl programs accept glibc binaries for dlopen(3)
Just add libgcompat.so to the DT_NEEDED entries in the ELF that you want to have the gcompat symbols available in. Use a tool such as PatchELF for this.
special environment variables
GLIBC_FAKE_VERSIONwill override the result of
gnu_get_libc_version, which currently defaults to "2.8".
GLIBC_FAKE_DEBUGwill cause dlmopen and dlvsym to display the overrides they are performing, and may cause additional output to stderr with other functions in the future.