Redox C Library (relibc)

relibc is a portable POSIX C standard library written in Rust and is under heavy development.

The motivation for this project is twofold: Reduce issues that the Redox developers were having with newlib, and create a safer alternative to a C standard library written in C. It is mainly designed to be used under Redox, as an alternative to newlib, but it also supports Linux system calls via the sc crate.

Currently Redox and Linux are supported.

redox-rt

redox-rt is our equivalent for vDSO from Linux.

Repository Layout

• include - Header files (mostly macros and variadic functions cbindgen can't generate)
• src - Source files
• src/c - C code
• src/crt0 - Runtime code
• src/crti - Runtime code
• src/crtn - Runtime code
• src/header - Header files implementation
• src/header/* - Each folder has a cbindgen.toml file, it generates a C-to-Rust interface and header files
• src/ld_so - Dynamic loader code
• src/platform - Platform-specific and common code
• src/platform/redox - Redox-specific code
• src/platform/linux - Linux-specific code
• src/pthread - pthread implementation
• src/sync - Synchronization primitives
• tests - C tests (each MR needs to give success in all of them)

Download the sources

To download the relibc sources run the following command:

git clone --recursive https://gitlab.redox-os.org/redox-os/relibc

Build Instructions

To build relibc out of the Redox build system, do the following steps:

Dependencies

• Install cbindgen

cargo install cbindgen

Install the expect tool

• Debian, Ubuntu and PopOS:

sudo apt install expect

• Fedora:

sudo dnf install expect

• Arch Linux:

sudo pacman -S expect

Build Relibc

To build the relibc library objects, run the following command:

make all

• Clean old library objects and tests

make clean

Build relibc inside the Redox build system

Inside of your Redox build system, run:

make prefix

If you need to rebuild relibc for testing a Cookbook recipe, run:

touch relibc
make prefix r.recipe-name

Touching (changing the "last modified time" of) the relibc folder is needed to trigger recompilation for make prefix. Replace recipe-name with your desired recipe name.

Note: Do not edit relibc inside prefix folder! Do your work on relibc folder directly inside your Redox build system instead.

Tests

This section explain how to build and run the tests.

Build

To build the tests run make all on the tests folder, it will store the executables at tests/bins_static

If you did changes to your tests, run make clean all to rebuild the executables.

Redox OS Testing

To test on Redox do the following steps:

• Add the relibc-tests recipe on your filesystem configuration at config/your-cpu/your-config.toml (generally desktop.toml)
• Run the following commands to rebuild relibc with your changes, update the relibc-tests recipe and update your QEMU image:

touch relibc

make prefix cr.relibc-tests image

• Run the tests

/usr/share/relibc-tests/bins_static/test-name

Linux Testing

Run make test on the relibc directory.

If you want to run one test, run the following command:

tests/bins_static/test-name

Issues

I'm building for my own platform which I run, and am getting x86_64-linux-gnu-ar: command not found (or similar)

The Makefile expects GNU compiler tools prefixed with the platform specifier, as would be present when you installed a cross compiler. Since you are building for your own platform, some Linux distributions (like Manjaro) don't install/symlink the prefixed executables.

An easy fix would be to replace the corresponding lines in the Makefile, e.g.

 ifeq ($(TARGET),x86_64-unknown-linux-gnu)
        export CC=x86_64-linux-gnu-gcc
-       export LD=x86_64-linux-gnu-ld
-       export AR=x86_64-linux-gnu-ar
+       export LD=ld
+       export AR=ar
        export OBJCOPY=x86_64-linux-gnu-objcopy
 endif

Contributing

Before starting to contribute, read this document.

Supported OSes

• Redox OS
• Linux

Supported architectures

• i686 (Intel/AMD)
• x86_64 (Intel/AMD)
• Aarch64 (ARM64)