crabc libc

crabc is an MIT/Apache-2.0 licensed implementation of the musl C library ABI and dynamic linker for Linux, written in Rust. It runs unmodified musl-linked binaries on x86_64, aarch64 and riscv64 when libldso.so is used as the interpreter, and provides libc.a for static linking. crabc is built on the principle that a libc should be small, easy to audit and safe to maintain; unsafe is confined to syscalls and pointer glue.

crabc tracks musl 1.2.6 and exports its full public symbol surface. It is validated with musl's own libc-test and a differential harness that runs the same binaries under musl and crabc, and it is faster than musl on both x86_64 and riscv64 (qemu-user) in the microbenchmark suite; process startup is the one structural exception. See docs/performance.md.

Real, unmodified Alpine binaries are tracked in the workload matrix: BusyBox, curl, Git, SQLite, nginx, Redis, CPython, Node.js and PostgreSQL all run under crabc, with a per-project report and baseline comparison. The LTP report records the syscalls, math, memory-management, scheduler, threading and SysV IPC suites against the same binaries under musl and crabc; the shared suites have identical failure lists.

Build and cross-compilation instructions are in AGENTS.md. Release builds are size-optimized and stripped, and are produced from v* tags; the workspace is published as the crabc, crabc-libc and crabc-ldso crates.

crabc is licensed under MIT OR Apache-2.0.