Michael Zimmerman, one of the main developers behind EFIDroid, also has another interesting UEFI side project: uefi-musl-toolchain, a port of the LibC library musl to UEFI!

Quoting Wikipedia, musl is “a C standard library intended for operating systems based on the Linux kernel, released under the MIT License. It was developed by Rich Felker with the goal to write a clean, efficient and standards-conformant libc implementation. It is designed from scratch to allow efficient static linking and to have realtime-quality robustness by avoiding races, internal failures on resource exhaustion and various other bad worst-case behaviours present in existing implementations. The dynamic runtime is a single file with stable ABI allowing race-free updates and the static linking support allows an application to be deployed as a single portable binary without significant size overhead. It claims compatibility with the POSIX 2008 specification and the C11 standard. It also implements most of the widely used non-standard Linux, BSD, and glibc functions.

On his musl port to UEFI, Michael says:

I ported the libc alternative musl to UEFI by replacing the syscalls with simple function calls to library and wrote a GCC wrapper. The system call table is still incomplete but this way I can compile any (single-threaded) application for UEFI. This currently works on ARM only, but just because this is the platform I am interested in, not because it wouldn’t be possible.

This is fresh code, the project is only 2 days old. 🙂

https://github.com/M1cha/uefi-musl-toolchain

Example of busybox on UEFI compiled using musl: http://pastebin.com/MRXdBjyN

https://www.musl-libc.org/