tlibc: Theseus's libc

This directory contains a custom libc implementation that targets the Theseus OS platform. Currently, tlibc is a work-in-progress and a proof of concept; it is missing most standard libc functionality.

Large portions of tlibc code have been borrowed from Redox's relibc to get up and running quickly, but will be replaced over time with equivalent Theseus-specific code.

It requires a cross-compiled version of gcc and binutils that will compile C code targeted at Theseus. Read more about how to build those here.

Manual build fixes

Currently, to get everything to build from scratch properly, we need to add the following manual steps to ensure the build process works:

1. Copy the [patch.crates-io] section from the top-level Theseus Cargo.toml file to the local tlibc/Cargo.toml file.
2. Attempt to build the tlibc project by running cargo clean && ./build.sh.
3. Adjust the contents of the Cargo.lock file to ensure that all of the crate dependencies have the same version as what's being used by the main Theseus build. For example:
   • qp-trie (changed to use the theseus-os fork on github)
   • linked_list_allocator (changed to use version 0.8.6 instead of 0.8.11)

Building as part of Theseus

Note that the above manual build fixes have already been done if you're checking this out from GitHub, so the Cargo.toml and Cargo.lock files should include the above necessary changes.

You should merely have to run make tlibc from the top-level Theseus directory.

To test it out with an actual C executable, run the following series of instructions:

# build the main Theseus ISO
make
# build tlibc and package it into the ISO
make c_test
# build a dummy C executable, statically link it to tlibc, and package it into the ISO
make tlibc
# run the ISO in QEMU, without rebuilding
make orun