Reduced Binary Seed Bootstrap

September 19, 2018

Guix---like other GNU/Linux distributions---is traditionally bootstrapped from a set of bootstrap binaries: Bourne shell, command-line tools provided by GNU Coreutils, Awk, Findutils, sed, and grep and Guile, GCC, Binutils, and the GNU C Library. Usually, these bootstrap binaries are "taken for granted."

Taking these binaries for granted means that we consider them to be a correct and trustworthy seed for building the complete system. Therein lies a problem: the current combined size of these bootstrap binaries is about 250MB . Auditing or even inspecting these is next to impossible.

For i686-linux and x86_64-linux, GuixSD now features a "Reduced Binary Seed" bootstrap (see the wip-bootstrap branch). We would like to say: "Full Source Bootstrap" and while we are working towards that goal it would be hyperbole to use that term for what we do now.

The Reduced Binary Seed bootstrap removes the most critical tools---from a trust perspective---from the bootstrap binaries: GCC, Binutils and the GNU C Library are replaced by: mescc-tools-seed (a tiny assembler and linker) mes-seed (a small Scheme Interpreter and a C compiler writen in Scheme) and tinycc-seed (the Mes C Library, built for TinyCC). Using these new binary seeds and a new set of packages (mescc-tools-boot, nyacc-boot, mes-boot, tcc-boot0, tcc-boot, make-mesboot0, diffutils-mesboot, binutils-mesboot0, gcc-core-mesboot, mesboot-headers, glibc-mesboot0, gcc-mesboot0, binutils-mesboot, make-mesboot, gcc-mesboot1, gcc-mesboot1-wrapper, glibc-headers-mesboot, glibc-mesboot, gcc-mesboot, and gcc-mesboot-wrapper) the "missing" Binutils, GCC, and the GNU C Library are built from source. From here on the more traditional bootstrap process resumes. This approach has reduced the bootstrap binaries in size to about 130MB. Work is ongoing to reduce this further. If you are interested, join us on #bootstrappable on the Freenode IRC network.

Below is the generated dependency graph for gcc-mesboot, the bootstrap compiler used to build the rest of GuixSD.