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0   bootstrap-seeds

This is where it all begins.

A kernel bootstrapping option is used by default at the beginning. The tiny builder-hex0-x86-stage1 binary seed boots, builds and runs the builder-hex0-x86-stage2 kernel. The builder-hex0-x86-stage1 and builder-hex0-x86-stage2 kernels are written in hex0. The stage2 kernel has its own built-in shell, the hex0 compiler and the src tool to load files into its memory file system. In this case the first step is to build the hex0-seed and kaem-optional-seed binaries from hex0 source.

Note that all early shells and compilers before mes are part of stage0-posix.

builder-hex0-x86-stage2 runs as the kernel for building the stage0-posix compilers and then mes and tcc. Then the Fiwix <> kernel is built and launched. Then Fiwix runs the build until Linux takes over.

If chroot or bwrap is specified or if a pre-existing kernel is provided then we start with the two raw binary seeds hex0-seed and kaem-optional-seed. We use those seeds to rebuild themselves.

1   hex0

hex0 is fairly trivial to implement and for each pair of hexadecimals characters it outputs a byte. We have also added two types of line comments (# and ;) to create a well commented lines like:

# :loop_options [_start + 0x6F]
    39D3            ; cmp_ebx,edx                 # Check if we are done
    74 14           ; je !loop_options_done       # We are done
    83EB 02         ; sub_ebx, !2                 # --options

In the first steps we use initial hex0 binary seed to rebuild kaem-optional and hex0 from their source.

hex0 code is somewhat tedious to read and write as it is basically a well documented machine code. We have to manually calculate all jumps in the code.

hex0 can be approximated with: sed 's/[;#].*$//g' $input_file | xxd -r -p > $output_file

2   builder-hex0-x86-stage1

By default (when kernel bootstrap is enabled), the builder-hex0-x86-stage1 boot loader/compiler boots from a hard drive and loads hex0 source code from disk, compiles, and runs the builder-hex0-x86-stage2 kernel. builder-hex0-x86-stage1 is written in hex0 and can be compiled with any one of hex0-seed, sed, or the tiny builder-hex0-mini binary.

3   builder-hex0-x86-stage2

When kernel bootstrap is enabled, the builder-hex0-x86-stage2 kernel loads an enormous shell script which embeds files (loaded with the src command) and the initial commands to build hex0-seed, kaem-optional-seed, and the command which launches stage0-posix using kaem-optional-seed and the stage0-posix launch script kaem.x86.

4   kaem-optional

kaem-optional is a trivial shell that can read list of commands together with their command line arguments from a file and executes them. It also supports line comments but has no other features.

5   hex1

This is the last program that has to be written in hex0 language. hex1 is a simple extension of hex0 and adds a single character labels and allows calculating 32-bit offsets from current position in the code to the label. hex1 code might look like:

:a #:loop_options
    39D3            ; cmp_ebx,edx                 # Check if we are done
    0F84 %b         ; je %loop_options_done       # We are done
    83EB 02         ; sub_rbx, !2                 # --options

6   hex2

hex2 is our final hex language that adds support for labels of arbitrary length. It also allows accessing them via 8, 16, 32-bit relative addresses (!, @, %) and via 16-bit or 32-bit ($, &) absolute addresses:

    39D3                  ; cmp_ebx,edx                        # Check if we are done
    74 !loop_options_done ; je8 !loop_options_done             # We are done
    83EB 02               ; sub_ebx, !2                        # --options

7   catm

catm allows concatenating files with catm output_file input1 input2 ... inputN. This allows us to distribute common code in separate files. We will first use it to append ELF header to .hex2 files. Before this step the ELF header had to be included in the source file itself.

8   M0

The M0 assembly language is the simplest assembly language you can create that enables the creation of more complicated programs. It includes only a single keyword: DEFINE and leverages the language properties of hex2 along with extending the behavior to populate immediate values of various sizes and formats.

Thus M0 code looks like:

DEFINE cmp_ebx,edx 39D3
DEFINE je 0F84
DEFINE sub_ebx, 81EB

    cmp_ebx,edx                         # Check if we are done
    je %loop_options_done               # We are done
    sub_ebx, %2                         # --options

9   cc_x86

The cc_x86 implements a subset of the C language designed in M0 assembly. It is a somewhat limited subset of C but complete enough to make it easy to write a more usable C compiler written in the C subset that cc_x86 supports.

At this stage we start using M2libc as our C library. In fact, M2libc ships two versions of C library. There is a single-file library that contains just enough to build M2-Planet and there is a full version that is rather well-featured.

10   M2-Planet

This is the only C program that we build with cc_x86. M2-Planet supports a larger subset of C than cc_x86 and we are somewhat closer to C89 (it does not implement all C89 features but on the other hand it does have some C99 features). M2-Planet also includes a very basic preprocessor, so we can use stuff like #define, #ifdef.

M2-Planet is also capable of using full M2libc C library that has more features and optimizations compared to bootstrap version of M2libc.

M2-Planet supports generating code for various architectures including x86, amd64, armv7, aarch64, riscv32 and riscv64. Up until this point bootstrap has been very architecture specific. From now on we still have platform specific bits of code but they are usually handled as conditionals in the same application rather than having completely different applications.

11   mescc-tools

Now we build blood-elf used to generate debug info, C version of hex2 (also called hex2) and C version of M0 called M1. These are more capable than their platform specific hex counterparts and are fully cross-platform. Thus we can now have the whole toolchain written in C.

Then we rebuild mescc-tools again, so all our tools are using new toolchain written in C.

Finally, we build kaem which is a more capable version of kaem-optional and adds support for variables, environmental variables, conditionals and aliases. It also has various built-ins such as cd and echo.

12   M2-Mesoplanet

M2-Mesoplanet is a preprocessor that is more capable than M2-Planet and supports #include statements. It can also launch compiler, assembler and linker with the correct arguments, so we don't need to invoke them manually.

At the moment it is only used to build mescc-tools-extra.

13   M2-Planet

We rebuild M2-Planet with M2-Planet.

From here, we can move on from the lowest level stuff.

14   mescc-tools-extra

mescc-tools-extra contains some additional programs, namely filesystem utilities cp and chown. This allows us to have one unified directory for our binaries. Furthermore, we also build sha256sum, a checksumming tool, that we use to ensure reproducibility and authenticity of generated binaries. We also build initial untar, ungz, unxz and unbz2 utilities to deal with compressed archives, as well as replace, a trivial search-and-replace program.

15   live-bootstrap seed

stage0-posix executes a file after.kaem, which creates a kaem script to continue the bootstrap. This is responsible for cleaning up the mess in /x86/bin and moving it to the permanent /usr/bin, and setting a few environment variables.

16   script-generator

script-generator is a program that translates live-bootstrap's domain-specific manifest language into shell scripts that can be run to complete the bootstrap. The translator is implemented in M2-Planet.

The language is fairly simple; each line has the format <directive>: <arguments> <predicate>. A predicate only runs the line if a particular condition is true.

The following directives are supported:

  • build, builds a particular package defined in steps/.
  • improve, runs a script making a distinct and logical improvement to the live bootstrap system.
  • define, defines a variable evaluated from other constants/variables.
  • jump, moves into a new rootfs/kernel using a custom script.
  • uninstall, removes a previously built package for file.

17   checksum-transcriber 1.0

checksum-transcriber is a small program that converts live-bootstrap's source specification for packages into a SHA256SUM file that can be used to checksum source tarballs.

18   simple-patch 1.0

simple-patch is a rudimentary patching program. It works by matching for a text block given to it, and replacing it with another text block. This is sufficient for the early patching required before we have full proper GNU patch.

19   mes 0.26

GNU mes is a scheme interpreter. It runs the sister project mescc, which is a C compiler written in scheme, which links against the Mes C Library. All 3 are included in this same repository. There are two stages to this part:

  1. Compiling an initial mes using M2-Planet. Note that this is only the Mes interpreter, not the libc or anything else.
  2. We then use this to recompile the Mes interpreter as well as building the libc. This second interpreter is faster and less buggy.

The mescc component depends on the nyacc parsing library, version 1.00.2. We use a modified version, 1.00.2-lb1, which incorporates Timothy Sample's changes required to bootstrap mescc without relying on pregenerated files.

From this point until musl, we are capable of making non-standard and strange libraries. All libraries are in /usr/lib/mes, and includes are in /usr/include/mes, as they are incompatible with musl.

20   tinycc 0.9.26

tinycc is a minimal C compiler that aims to be small and fast. It complies with all C89 and most of C99 standards.

First, we compile jannekes fork of tcc 0.9.26 using mescc, containing 27 patches to make it operate well in the bootstrap environment and make it compilable using mescc. This is a non-trivial process and as seen within tcc. kaem has many different parts within it: a. tcc 0.9.26 is first compiled using mescc. b. The mes libc is recompiled using tcc (mescc has a non-standard .a format), including some additions for later programs. c. tcc 0.9.26 is recompiled 3 times to add new features, namely long long and float. Each time, the libc is also recompiled.

21   tinycc 0.9.27

Now, we compile upstream tcc 0.9.27, the latest release of tinycc, using the final version of tcc 0.9.26.

From this point onwards, until further notice, all programs are compiled using tinycc 0.9.27.

Note that now we begin to delve into the realm of old GNU software, using older versions compilable by tinycc. Prior to this point, all tools have been adapted significantly for the bootstrap; now, we will be using old tooling instead.

22   fiwix 1.5.0-lb1

If the kernel bootstrap option is enabled then the Fiwix kernel is built next. This is a Linux 2.0 clone which is much simpler to understand and build than Linux. This version of Fiwix is an intermediate release on top of 1.5.0 that contains many modifications and enhancements to support live-boostrap.

23   lwext4 1.0.0-lb1

If the kernel bootstrap option is enabled then lwext4 <> is built next. This is a library for creating ext2/3/4 file systems from user land. This is combined with a program called make_fiwix_initrd.c which creates and populates an ext2 files system which Fiwix uses for an initial ram drive (initrd). This file system contains all of the files necessary to build Linux.

24   kexec-fiwix

If the kernel bootstrap option is enabled then a C program kexec-fiwix is compiled and run which places the Fiwix ram drive in memory and launches the Fiwix kernel.

25   make 3.82

GNU make is now built so we have a more robust building system. make allows us to do things like define rules for files rather than writing complex kaem scripts.

26   patch 2.5.9

patch is a very useful tool at this stage, allowing us to make significantly more complex edits, including just changes to lines.

27   gzip 1.2.4

gzip is the most common compression format used for software source code. It is more capable than ungz from stage0-posix and also supports compression.

28   tar 1.12

We build GNU Tar 1.12, the last version compilable with mes libc.

29   sed 4.0.9

You are most likely aware of GNU sed, a line editor.

30   bzip2 1.0.8

bzip2 is a compression format that compresses more than gzip. It is preferred where we can use it, and makes source code sizes smaller.

31   coreutils 5.0

GNU Coreutils is a collection of widely used utilities such as cat, chmod, chown, cp, install, ln, ls, mkdir, mknod, mv, rm, rmdir, tee, test, true, and many others.

A few of the utilities cannot be easily compiled with Mes C library, so we skip them.

The cp in this stage replaces the mescc-tools-extra cp.

32   byacc 20240109

The Berkeley Yacc parser generator, a public-domain implementation of the yacc utility. Differently from the analogous bison utility from the GNU project, it can be compiled with a simple Makefile.

Some code is backported from an earlier version of byacc, 20140101, because of an incompatibility of newer versions with meslibc.

33   bash 2.05b

GNU bash is the most well known shell and the most complex piece of software so far. However, it comes with a number of great benefits over kaem, including proper POSIX sh support, globbing, etc.

Bash ships with a bison pre-generated file here which we delete. Unfortunately, we have not bootstrapped bison but fortunately for us, Berkeley Yacc is able to cope here.

34   setup_repo

This is a simple script that sets up the /external/repo directory to hold binary tarballs of artifacts built in each step. It also creates base.tar.bz2, a tarball containing every artifact built before setup_repo, which have no individual repository tarballs corresponding to them.

From this point on, every package is built and installed into a temporary directory, packaged from there into a repository tarball, and then installed onto the live system from the newly built repository tarball.

35   update_env

This is a simple script that makes some small updates to the env file that were not possible when using kaem.

36   merged_usr

Sets up symlinks from folders outside the /usr hierarchy to the corresponding /usr ones ("merged-usr" file system layout).

37   populate_device_nodes

Sets up important device nodes under /dev. These nodes are temporary, as once the Linux kernel is started, devtmpfs is used to maintain /dev.

38   open_console

In interactive mode only, sets up an interactive Bash console, accessible by pressing Ctrl+Alt+F2. Because the early Bash doesn't support true interactive operation, we emulate it using a REPL. A side effect of this is that after every command entered, one must press Enter followed by Ctrl+D, rather than just Enter as with a real interactive shell.

39   tcc 0.9.27 (patched)

We recompile tcc with some patches needed to build musl.

40   musl 1.1.24 and musl_libdir

musl is a C standard library that is lightweight, fast, simple, free, and strives to be correct in the sense of standards-conformance and safety. musl is used by some distributions of GNU/Linux as their C library. Our previous Mes C library was incomplete which prevented us from building many newer or more complex programs.

tcc has slight problems when building and linking musl, so we apply a few patches.

We do not use any of /usr/lib/mes or /usr/include/mes any longer, rather using /usr/lib and /usr/include like normal.

41   tcc 0.9.27 (musl)

We recompile tcc against musl. This is a two stage process. First we build tcc-0.9.27 using tcc-0.9.26 that itself links to Mes C library but produces binaries linked to musl. Then we recompile newly produced tcc with itself. Interestingly, tcc-0.9.27 linked against musl is self hosting.

42   musl 1.1.24 (tcc-musl)

We now rebuild musl with the just built tcc-musl, which fixes a number of bugs, particularly regarding floats, in the first musl.

43   tcc 0.9.27 (musl v2)

Now that we have a fixed musl, we now recompile tcc as tcc uses floats extensively.

44   sed 4.0.9

sed is rebuilt against musl.

45   bzip2 1.0.8

bzip2 is rebuilt unpatched with the new tcc and musl fixing issues with reading files from stdin that existed in the previous build.

46   m4 1.4.7

m4 is the first piece of software we need in the autotools suite, flex 2.6.4 and bison. It allows macros to be defined and files to be generated from those macros.

47   heirloom devtools

lex from the Heirloom project. The Heirloom project is a collection of standard UNIX utilities derived from code by Caldera and Sun. Differently from the analogous utilities from the GNU project, they can be compiled with a simple Makefile.

Because issues with the Heirloom version of yacc compiled against musl, we continue using Berkeley Yacc together with Heirloom lex for the next few steps.

48   flex 2.5.11

flex is a tool for generating lexers or scanners: programs that recognize lexical patterns.

Unfortunately flex also depends on itself for compiling its own scanner, so first flex 2.5.11 is compiled, with its scanner definition manually modified so that it can be processed by lex from the Heirloom project (the required modifications are mostly syntactical, plus a few workarounds to avoid some flex advanced features).

49   flex 2.6.4

We recompile unpatched GNU flex using older flex 2.5.11. This is again a two stage process, first compiling flex using scan.c (from scan.l) created by old flex, then recompile scan.c using the new version of flex to remove any buggy artifacts from the old flex.

50   bison 3.4.1

GNU bison is a parser generator. With m4 and flex we can now bootstrap it following Its a 3 stage process:

  1. Build bison using a handwritten grammar parser in C.
  2. Use bison from previous stage on a simplified bison grammar file.
  3. Build bison using original grammar file.

Finally we have a fully functional bison executable.

51   grep 2.4

GNU grep is a pattern matching utility. Is is not immediately needed but will be useful later for autotools.

52   diffutils 2.7

diffutils is useful for comparing two files. It is not immediately needed but is required later for autotools.

53   coreutils 5.0

coreutils is rebuilt against musl. Additional utilities are built including comm, expr, dd, sort, sync, uname and uniq. This fixes a variety of issues with existing coreutils.

54   coreutils 6.10

We build date, mktemp and sha256sum from coreutils 6.10 which are either missing or don't build correctly in 5.0. Other utils are not built at this stage.

55   gawk 3.0.4

gawk is the GNU implementation of awk, yet another pattern matching and data extraction utility. It is also required for autotools.

56   perl 5.000

Perl is a general purpose programming language that is especially suitable for text processing. It is essential for autotools build system because automake and some other tools are written in Perl.

Perl itself is written in C but ships with some pre-generated files that need perl for processing, namely embed.h and keywords.h. To bootstrap Perl we will start with the oldest Perl 5 version which has the fewest number of pregenerated files. We reimplement two remaining perl scripts in awk and use our custom makefile instead of Perls pre-generated Configure script.

At this first step we build miniperl which is perl without support for loading modules.

57   perl 5.003

We now use perl from the previous stage to recreate pre-generated files that are shipped in perl 5.003. But for now we still need to use handwritten makefile instead of ./Configure script.

58   perl 5.004_05

Yet another version of perl; the last version buildable with 5.003.

59   perl 5.005_03

More perl! This is the last version buildable with 5.004. It also introduces the new pregenerated files regnodes.h and byterun.{h,c}.

60   perl 5.6.2

Even more perl. 5.6.2 is the last version buildable with 5.005.

61   autoconf 2.52

GNU Autoconf is a tool for producing configure scripts for building, installing and packaging software on computer systems where a Bourne shell is available.

At this stage we still do not have a working autotools system, so we manually install autoconf script and replace a few placeholder variables with sed.

Autoconf 2.52 is the newest version of autoconf that does not need perl, and hence a bit easier to install.

This is not a full featured autoconf install, it is missing other programs such as autoheader but is sufficient to build autoconf 2.53.

62   automake 1.6.3

GNU Automake is a tool for automatically generating files. It is another major part of GNU Autotools build system and consists of aclocal and automake scripts.

We bootstrap it using a 2 stage process:

  1. Use sed to replace a few placeholder variables in script. Then we manually install aclocal script and its dependencies.
  2. Patch to create automake file but skip processing. Again we manually install automake script and its dependencies.

63   autoconf 2.53

We now start bootstrapping newer versions of autoconf. Version 2.53 now uses perl. In order to build it with autoconf-2.52 we have to patch it a bit.

64   automake 1.7

Automake 1.7 and Autoconf 2.54 depend on each other, so we patch out two offending autoconf macros to make it build with autoconf-2.53.

65   autoconf 2.54

Never version of autoconf.

66   autoconf 2.55

Even newer autoconf. This is the last version of autoconf that is buildable with automake-1.7.

67   automake 1.7.8

Newer automake. This is the latest automake that is buildable with autoconf-2.55.

68   autoconf 2.57

Newer autoconf. This time we were able to skip version 2.56.

69   autoconf 2.59

Again, we managed to skip one version.

70   automake 1.8.5

We need newer automake to proceed to newer autoconf versions. This is the latest automake version from 1.8 release series.

71   help2man 1.36.4

help2man automatically generates manpages from programs --help and --version outputs. This is not strictly required for bootstrapping but will help us to avoid patching build process to skip generation of manpages. This is the newest version of help2man that does not require Perl 5.8.

72   autoconf 2.61

Yet another version of autoconf.

73   automake 1.9.6

Latest GNU Automake from 1.9 series. Slightly annoyingly depends on itself but it is easy to patch to make it buildable with 1.8.5.

74   automake 1.10.3

GNU Automake from 1.10 series. aclocal is slightly patched to work with our perl.

75   autoconf 2.64

Slightly newer version of GNU Autoconf. At this stage Autoconf is mostly backwards compatible but newer versions need newer automake.

76   automake 1.11.2

GNU Automake from 1.11 series. This is not the latest point release as newer ones need Autoconf 2.68. Newer major version of automake also depends on a newer bash.

77   autoconf 2.69

This is a much newer version of GNU Autoconf.

78   libtool 2.2.4

GNU Libtool is the final part of GNU Autotools. It is a script used to hide away differences when compiling shared libraries on different platforms.

79   automake 1.15.1

GNU Automake from 1.15 series. This is the last version that runs on Perl 5.6.

80   binutils 2.30

The GNU Binary Utilities, or binutils, are a set of programming tools for creating and managing binary programs, object files, libraries, profile data, and assembly source code.

In particular we can now use full featured ar instead of tcc -ar, the GNU linker ld, which allows us building shared libraries, and the GNU assembler as.

81   musl 1.1.24 (v3)

We rebuild musl for the third time. This time we can use GNU as to build assembly source files, so those assembly files that tcc failed to compile no longer have to be patched.

82   tcc 0.9.27 (musl v3)

We rebuild tcc against new musl.

83   gcc 4.0.4

The GNU Compiler Collection (GCC) is an optimizing compiler produced by the GNU Project. GCC is a key component of the GNU toolchain and the standard compiler for most projects related to GNU and the Linux kernel.

Only the C frontend is built at this stage.

At this stage we are not yet able to regenerate top-level which needs GNU Autogen and hence Guile. Luckily, building GCC without top-level Makefile is fairly easy.

84   findutils 4.2.33

GNU Find Utilities can be used to search for files. We are mainly interested in find and xargs that are often used in scripts.

85   musl 1.2.4

GCC can build the latest as of the time of writing musl version.

We also don't need any of the TCC patches that we used before. To accomodate Fiwix, there are patches to avoid syscalls set_thread_area and clone.

86   Linux headers 4.14.341-openela

This gets some headers out of the Linux kernel that are required to use the kernel ABI, needed for util-linux.

The version of the Linux kernel used comes from the Open Enterprise Linux Association, who maintain this version as a continuation of the now ended 4.14 LTS release, to the same maintenance standards as the LTS. Because this isn't directly available as an efficiently compressed tarball, we start with the final LTS release, version 4.14.336, and apply the differences using a patch file.

87   gcc 4.0.4

Rebuild GCC with GCC and also against the latest musl.

88   util-linux 2.19.1

util-linux contains a number of general system administration utilities. This gives us access to a much less crippled version of mount and mknod. The latest version is not used because of autotools/GCC incompatibilities.

89   dhcpcd 10.0.1

dhcpcd is a DHCP client daemon, which we later use to obtain an IP address. Only wired interfaces are supported at the moment.

90   kbd 1.15

kbd contains loadkeys which is required for building the Linux kernel. The 2.x series is not used because it requires particular features of autotools that we do not have available.

91   make 3.82

GNU make is now rebuilt properly using the build system and GCC, which means that it does not randomly segfault while building the Linux kernel.

92   ed 1.4

ed is a very basic line editor. This is the last version that is not distributed in .tar.lz format. ed is used by bc build scripts.

93   bc 1.07.1

bc is a console based calculator that is sometime used in scripts. We need bc to rebuild some Linux kernel headers.

94   kexec-linux

If the kernel bootstrap option is enabled then a C program kexec-linux is compiled. This can be used to launch a Linux kernel from Fiwix (when not using --kernel).

95   kexec-tools 2.0.22

kexec is a utility for the Linux kernel that allows the re-execution of the Linux kernel without a manual restart from within a running system. It is a kind of soft-restart. It is only built for non-chroot mode, as we only use it in non-chroot mode. It is used to boot the Linux kernel that will be built next from the current Linux kernel (when using --kernel).

96   clean_sources

A script to remove source tarballs no longer needed for subsequent build steps from distfiles. This frees space for the Linux kernel build.

97   clean_artifacts

More space freeing in preparation for the kernel build. This time, we clear out any artifacts left over from previous builds that weren't packaged in a proper repository tarball or base.tar.bz2

98   Linux kernel 4.14.341-openela

A lot going on here. This is the first (and currently only) time the Linux kernel is built. Firstly, Linux kernel version 4.14.y is used because newer versions require much more stringent requirements on the make and GCC versions. This is also modern enough for most hardware and to cause few problems with software built afterwards. Secondly, since 4.14.y is no longer supported by, we use the last available tarball, 4.14.336, and patch it up to 4.14.341-openela, maintained by the Open Enterprise Linux Association as an ELTS version. Pregenerated files in the kernel have file names appended with _shipped so we use a find command to remove those, which are automatically regenerated. The kernel config was originally taken from Void Linux, and was then modified for the requirements of live-bootstrap, including compiler features, drivers, and removing modules. Modules are unused. They are difficult to transfer to subsequent systems, and we do not have modprobe.

The linux-libre scripts are no longer used to deblob the kernel, due to undesirable modifications they make beyond just deblobbing. Instead, the remaining 4 drivers that ship binary blobs in line with source code are stripped using a patch - neither of these drivers are relevant to bootstrapping.

The kernel is built in 2 stages:

  1. We build vmlinux and all of its dependencies.
  2. After clearing away any unnecessary intermediate files, we build the final bzImage kernel. This is necessary because the whole build wouldn't fit in Fiwix's initrd image all at once.

We then kexec to use the new Linux kernel, using kexec-tools for a Linux kernel and kexec-linux for Fiwix.

99   move_disk

In kernel-bootstrap mode, we have been working off an initramfs for some things up until now. At this point we are now capable of moving to it entirely, so we do so.

100   finalize_job_count

In kernel-bootstrap mode, up until this point, we had no multiprocessor support, and very limited RAM, so all builds used only one thread. At this point, we allow the full selected thread count to take effect, speeding up subsequent builds thanks to parallelization.

101   finalize_fhs

Sets up the file system as per the Filesystem Hierarchy Standard (FHS), creating directories and mounting pseudo-filesystems as necessary.

102   open_console

In interactive mode only, sets up an interactive Bash console, accessible by pressing Ctrl+Alt+F2, again. This is still the early Bash, requiring Ctrl+D.

103   swap

If enabled in bootstrap.cfg, creates and activates a swap file under the name /swapfile.

104   musl 1.2.4

At this point, it is guaranteed that we are running on Linux with thread support, so we rebuild musl with thread support.

105   curl 8.5.0 and get_network

curl is used to download files using various protocols including HTTP and HTTPS. However, this first build does not support encrypted HTTPS yet. curl requires Linux and musl with thread support, which are now available.

Once curl is built, we use dhcpcd to set up networking for downloading subsequent source packages.

106   bash 5.2.15

This new version of bash compiles without any patches, provides new features, and is built with GNU readline support so it can be used as a fully-featured interactive shell. autoconf-2.69 is used to regenerate the configure script and bison is used to recreate some included generated files.

107   open_console

Now that we have a proper interactive shell available, open another interactive console (only in interactive mode), this time accessible using Ctrl+Shift+F3, since Ctrl+Shift+F2 is already occupied by our previous console, running the old Bash.

108   xz 5.4.1

XZ Utils is a set of free software command-line lossless data compressors, including lzma and xz. In most cases, xz achieves higher compression rates than alternatives like gzip and bzip2.

109   file 5.44

file is a utility that is used to get information about files based upon their magic.

110   libtool 2.4.7

A modern version of libtool with better compatibility with newer versions of GNU Autotools.

111   tar 1.34

Newer tar has better support for decompressing .tar.bz2 and .tar.xz archives. It also deals better with modern tar archives with extra metadata.

112   coreutils 9.4

We build the latest available coreutils 9.4 which adds needed options to make results of build metadata reproducible. For example, timestamps are changed with touch --no-dereference.

113   pkg-config 0.29.2

pkg-config is a helper tool that helps to insert compile and link time flags.

114   make 4.2.1

A newer version of make built using autotools is much more reliable and is compiled using a modern C compiler and C library. This removes a couple of segfaults encountered later in the process and allows more modern make features to be used. We do not go for the latest because of the use of automake 1.16 which we do not have yet.

115   gmp 6.2.1

GNU Multiple Precision Arithmetic Library (GMP) is a free library for arbitrary-precision arithmetic, operating on signed integers, rational numbers, and floating-point numbers.

GMP is required by newer versions of GCC and Guile.

116   autoconf-archive 2021.02.19

The GNU Autoconf Archive is a collection of Autoconf macros that are used by various projects and in particular GNU MPFR.

117   mpfr 4.1.0

The GNU Multiple Precision Floating-Point Reliable Library (GNU MPFR) is a library for arbitrary-precision binary floating-point computation with correct rounding, based on GNU Multi-Precision Library.

118   mpc 3.2.1

GNU MPC is a library for multiprecision complex arithmetic with exact rounding based on GNU MPFR.

119   flex 2.5.33

An older version of flex is required for bison 2.3. We cannot use 2.5.11 that was compiled much earlier, as it does not produce reproducible output when building bison 2.3.

120   bison 2.3

This is an older version of bison required for the bison files in perl 5.10.1. We backwards-bootstrap this from 3.4.1, using 3.4.1 to compile the bison files in 2.3. This parser works sufficiently well for perl 5.10.1.

121   bison 3.4.2

Bison 3.4.1 is buggy and segfaults when perl 5.32.1 is built. This is probably because it was built with a hand-written makefile. We do not build the latest bison because perl 5.32.1 requires bison <= 3.4.2.

122   perl 5.10.1

Perl 5.10.1 is an intermediate version used before Perl 5.32. We require this version as it adds a couple of modules into lib/ required to regenerate files in Perl 5.32. We still use the Makefile instead of the metaconfig strategy, as metaconfig history becomes poor more than a few years back.

123   dist 3.5-236

dist is perl's package used for generating Perl's Configure (which is written in Perl itself). We 'compile' (aka generate) metaconfig and manifake only from dist. We do not use dist's build system because it itself uses dist.

124   perl 5.32.1

We finally compile a full version of Perl using Configure. This includes all base extensions required and is the latest version of Perl. We are now basically able to run any Perl application we want.

125   libarchive 3.5.2

libarchive is a C library used to read and write archives.

126   openssl 3.0.13

OpenSSL is a C library for secure communications/cryptography.

We do not use the latest 3.3.0 release because it causes lockups in curl.

127   curl 8.5.0

We rebuild curl with support for OpenSSL.

128   zlib 1.2.13

zlib is a software library used for data compression and implements an abstraction of DEFLATE algorithm that is also used in gzip.

129   automake 1.16.3

GNU Automake from 1.16 series that required newer Perl.

130   autoconf 2.71

GNU Autoconf 2.71 is even newer version of autoconf. It does not build with miniperl, so we postponed it until full perl was built.

131   patch 2.7.6

Our old patch was built with manual makefile and used mes libc. This is a newer version which we need in order to import gnulib into gettext.

132   gettext 0.21

GNU Gettext is an internationalization and localization system used for writing multilingual programs.

133   texinfo 6.7

Texinfo is a typesetting syntax used for generating documentation. We can now use makeinfo script to convert .texi files into .info documentation format.

134   gcc 4.7.4

GCC 4.7.4 is the last version written in C. This time we build both C and C++ backends. The C++ backend has a dependency on gperf, which is written in C++. Fortunately, it is easy to patch it out; the resulting g++ compiler is capable of building gperf. We also add in two patchsets to the compiler;

  • one to add support for musl shared library support
  • one providing a few compiler flags/features that are required later to build GCC 10

135   binutils 2.41

This version of binutils provides a more comprehensive set of programming tools for creating and managing binary programs. It also includes modern versions of the ld linker, the as assembler and the ar program.

136   gperf 3.1

gperf is a perfect hash function generator (hash function is injective).

137   libunistring 0.9.10

Library for manipulating Unicode and C strings according to Unicode standard. This is a dependency of GNU Guile.

138   libffi 3.3

The libffi library provides a portable, high level programming interface to various calling conventions.

139   libatomic_ops 7.6.10

libatomic_ops provides semi-portable access to hardware-provided atomic memory update operations on a number of architectures.

140   boehm-gc 8.0.4

The Boehm-Demers-Weiser conservative garbage collector can be used as a garbage collecting replacement for C malloc or C++ new.

141   guile 3.0.9

GNU Ubiquitous Intelligent Language for Extensions (GNU Guile) is the preferred extension language system for the GNU Project and features an implementation of the programming language Scheme.

We use guile-psyntax-bootstrapping project on Guile 3.0.7 to bootstrap Guile's psyntax.pp without relying on pre-expanded code. This is then transplanted into Guile 3.0.9.

142   which 2.21

which shows the full path of (shell) commands. It mostly duplicates bash built-in command -v but some scripts call which instead. In particular, autogen scripts use it.

143   grep 3.7

Newer grep will be needed to bootstrap autogen.

144   sed 4.8

Earlier sed was built with manual makefile with most features compiled out. Build a newer sed using GNU Autotools build system. In particular this will let sed keep executable bit on after in place editing.

145   autogen 5.18.16

GNU Autogen is a tool designed to simplify the creation and maintenance of programs that contain large amounts of repetitious text. Unfortunately, the source is full of pregenerated files that require autogen to rebuild.

We use the gnu-autogen-bootstrapping project to rebuild those and create (slightly crippled) autogen that is then able to build a full-featured version.

146   musl 1.2.4

With GCC and binutils supporting a musl-based toolchain natively, musl itself is rebuilt with support for dynamic linking.

147   python 2.0.1

Everything is in place to bootstrap the useful programming language/utility Python. While Python is largely written in C, many parts of the codebase are generated from Python scripts, which only increases as Python matured over time.

We begin with Python 2.0.1, which has minimal generated code, most of which can be removed. Lib/{keyword,token,symbol} scripts are rewritten in C and used to regenerate parts of the standard library. Unicode support and sre (regex) support is stripped out.

Using the stripped-down first version of Python 2.0.1, Python 2.0.1 is rebuilt, including Unicode and regex support (required for future Python builds). The first version is insufficient to run the Lib/{keyword,token,symbol} scripts, so those continue to use the C versions.

Precompiled Python code at this point is highly unreproducible, so it is deleted (JIT compiled instead). This makes Python itself slower, but this is of little consequence.

148   python 2.3.7

Python 2.0.1 is sufficient to build Python 2.3.7.

Differences to 2.0.1:

  • The new "ast" module, performing parsing of Python, is generated from a parsing specification using Python code.
  • 2.0.1 is insufficient to run 2.3.7's unicode regeneration, so Unicode support is again stripped out.

Python 2.3.7 is then rebuilt to include Unicode support.

149   python 2.5.6

Python 2.3.7 is sufficient to build Python 2.5.6, with a few minimal changes to language constructs in scripts. This is the last 2.x version we build.

Differences to 2.3.7 are very minimal.

150   python 3.1.5

Python 2.5.6 is new enough to be able to build Python 3.1.5, allowing us to move into the modern 3.x series of Python. Various patching is required, as some scripts in the tree are still Python 2 while others are Python 3. We have to convert the Python 3 ones back to Python 2 to be able to use Python 2.5.6.

Differences to 2.5.6:

  • An include cycle when a distributed file is removed arises, we have to jump through some hoops to make this work.
  • At the second pass of building, various charset encodings can be regenerated & used in the standard library (required in future Python 3.x).
  • The new ssl Python library is disabled due to our OpenSSL version being too new.

Python 3.1.5 is rebuilt, using Python 3 for the Python 3 scripts in the tree.

151   python 3.3.7

Python 3.1.5 is sufficient to build Python 3.3.7 (rapid language change = small jumps).

Differences to 3.1.5:

  • The ssl Python library can now be re-enabled, and _ssl_data.h regenerated.

152   python 3.4.10

Python 3.3.7 is sufficient to build Python 3.4.10.

Differences to 3.3.7:

  • The clinic tool has been introduced, which unifies documentation with code. Clinic creates many generated files. We run the clinic tool across all files using clinic.
  • The ssl library breaks in much more ugly ways than before, but unlike previous versions, it passes over this error silently.

153   python 3.8.16

Python 3.4.10 is sufficient to build Python 3.8.16.

Differences to 3.4.10:

  • The build system has been significantly revamped (coming in line with modern standards).
  • Many of our previous regenerations can be replaced with one make regen-all invocation.
  • The stringprep Python module, previously deleted, is now required, so it is regenerated.

154   python 3.11.1

The newest version of Python, Python 3.11.1 can now be built.

Differences to 3.8.16:

  • Unfortunately, the build system has regressed slightly. We must choose the order to perform regenerations in the Makefile ourselves, as some regenerations use other regenerations, but the Makefile does not include them as dependencies.
  • The concept of "frozen" modules has been introduced, adding a layer of complexity to regeneration.
  • stdlib_module_names.h is a new file that must be built using data from a current Python binary. To achieve this, a dummy stdlib_module_names.h is used for the build, then stdlib_module_names.h is created, and Python is rebuilt using the proper stdlib_module_names.h. Unfortunately this greatly increases the time taken to build Python, but it is not trivial to work around.
  • A new generated script Lib/re/ is introduced.
  • The ssl module, now unbroken, can be built again.
  • Very recent Python versions allow for the use of SOURCE_DATE_EPOCH to make output of precompiled Python libraries (.pyc) deterministic. Finally, we can re-enable compiling of Python modules.

155   gcc 10.4.0

GCC 10.x series is the last version of GCC that is able to be built with the C/C++ standards available in GCC 4.7. Instead of manually configuring & compiling every subdirectory, since we now have autogen available we are able to use the top-level configure to build the project. We do not use GCC's bootstrap mode, where GCC is recompiled with itself after being built, since we're just going to use this GCC to compile GCC 13, it adds build time for little benefit.

156   binutils 2.41 (pass 2)

We recompile Binutils with the full intended autogen top-level build system, instead of the subdirectory build system used before. This creates a binutils that functions completely correctly for the build of GCC 13 (eg, fixes the mistaken plugin loading support). Other modern features are added, including;

  • threaded linking
  • 64-bit linking on 32-bit x86
  • the modern, rewritten gold linker used by some distributions

157   gcc 13.1.0

This is the most recent version of GCC. With this version of GCC, the final gcc-binutils-musl toolchain is complete. The focus of further builds shifts to rebuilds for correctness, cleanup and preparation for downstream consumption.

In line with this, a variety of modern features + minor build changes are used to ensure the compiler is suitable for downstream consumption;

  • A full internal GCC bootstrap is used to ensure there are no lagging historical problems.
  • PIE and SSP are enabled by default, as is done on every major modern Linux distribution.
  • libssp is disabled and handed off to the libc (done by many modern Linux distributions). libssp in GCC is very broken and glibc-centric - it should really be handled by the libc, which is what most distributions do.
  • LTO now fully functions correctly, despite both the linker and the compiler being static binaries.

158   libmd 1.1.0

libmd provides message digest functions. In GNU/Linux, this is typically provided by glibc, but we need libmd to provide it since we are using musl.

159   libbsd 0.11.8

libbsd provides BSD-centric functions. We need this in order to build shadow, which expects either glibc or libbsd.

160   shadow 4.14.3

shadow provides a variety of command line utilites to work with users and groups, avoiding the need for manual modification of /etc/passwd and /etc/group. This allows unprivileged users to be created by, or for, post-bootstrap build systems.

161   opendoas 6.8.2

opendoas is a port of 'doas' from OpenBSD to Linux. It has all functions of sudo that could be conceivably needed in live-bootstrap, and is much simpler to build. This allows build systems that expect sudo after live-bootstrap to use it.

162   gzip 1.13

The version of gzip we have been using up until now is really old, all the way back from mes libc era! Somehow we've managed not to have any problems with it, though. This builds a gzip that is properly packaged and can be handled by all modern build systems.

163   diffutils 3.10

We already have a perfectly functional diffutils, but some core modern software does require newer diffutils (understandably, given our diffutils is from 1994). This also gives the additional diffutils commands diff3 and sdiff.

164   gawk 5.3.0

Similarly to diffutils, our gawk is currently very ancient (1999). That doesn't cut it for modern software such as glibc. We update gawk to a much more modern version.

165   m4 1.4.19

We are in need of a newer version of m4 for some modern software. Attempts to update m4 1.4.7 earlier in the bootstrap demonstrate some issues with Fiwix, so we build a newer m4 at the end of the bootstrap instead.

166   cleanup_filesystem

Remove any remaining loose build artifacts from steps. If preseeding was used, this step also removes the repo-preseeded directory.

167   null_time

If FORCE_TIMESTAMPS is enabled, resets all file times in the file system to the Unix epoch, to ensure maximum file system reproducibility.

168   update_checksums

If checksum updating is enabled, regenerates SHA256SUMS.pkgs to contain the actual hashes of the packages just built.

169   after

At the end of the bootstrap, executes any additional shell scripts placed in the /steps/after directory (if it exists), opens an interactive console (only in interactive mode), and finally ensures a clean shutdown of the bootstrap system (only needed in qemu and on bare metal).