Re: Building Hurd

[Sergey Bugaev]

On Tue, Jan 24, 2023 at 8:23 PM Ryan Raymond <rjraymond@oakland.edu> wrote:
>
> Hello,
> I was reading the install instructions and I saw that they were incomplete. 
> The system can't build right now I guess, but I wanted to fix that. I was 
> wondering if the last person who built could point me in the general 
> direction of how they think hurd is supposed to build?

Hello!

I'm unlikely to be the *last* person who compiled the Hurd, but I have
cross-compiled it from GNU/Linux just recently, and importantly I have
written some notes on how to do so. Dumping them below, hope this will
be useful. If you don't need to cross-compile, i.e. if you already
have a working Hurd installation; it's even easier, it's just
./configure && make.

Sergey

----

Install dependencies: bison, flex, the three libraries GCC needs.

Set up the basic directory structure:

$ export PREFIX=~/dev/crosshurd
$ export PATH=$PREFIX/bin:$PATH
$ mkdir $PREFIX && cd $PREFIX
$ mkdir src include i686-gnu
$ ln -s ../include i686-gnu/sys-include
$ ln -s ../lib i686-gnu/lib
$ cd src

Build binutils:

$ wget https://ftp.gnu.org/gnu/binutils/binutils-2.39.tar.gz
$ tar xf binutils-2.39.tar.gz
$ cd binutils-2.39
$ mkdir build && cd build
$ ../configure --target=i686-gnu --prefix=$PREFIX --with-lib-path=$PREFIX/lib
$ make -j8
$ make install

Verify that e.g. `$PREFIX/bin/i686-gnu-nm -v` works.

Now build GCC:

$ wget https://ftp.gnu.org/gnu/gcc/gcc-12.2.0/gcc-12.2.0.tar.gz
$ tar xf gcc-12.2.0.tar.gz
$ cd gcc-12.2.0
$ mkdir build && cd build
$ ../configure --prefix=$PREFIX --target=i686-gnu
--with-lib-path=$PREFIX/lib --disable-multilib --enable-languages=c
$ make -j8 all-gcc
$ make install-gcc

Note that at this step we're only building GCC itself, not libgcc --
that will have to wait until we install glibc headers.

Next, we want to build MIG. MIG needs Mach headers, but we can't build
GNU Mach without MIG. So what we do is we 'make' GNU Mach twice, once
to install the headers, and later on once more to actually build it.

$ git clone git://git.savannah.gnu.org/hurd/gnumach.git
$ cd gnumach
$ autoreconf -i
$ mkdir build && cd build
$ CC=gcc ../configure --prefix=$PREFIX --host=i686-gnu
$ make install-data

At configuring step, it will warn that "mig was not found, we will not
be able to build a kernel, only install headers. Install or build mig
against them, and run configure again". This is exactly how we want it
at this first step.

The trick here is to tell configure to use host's GCC instead of our
previously built i686-gnu-gcc. This is because we are not yet building
GNU Mach for real, we're only doing this to install the headers. But
we need to appease configure into generating a Makefile for us, hence
CC=gcc.

Now we should have $PREFIX/include/mach/message.h,
$PREFIX/include/mach/i386/machine_types.defs and suchlike.

Now, onto building MIG:
$ git clone git://git.savannah.gnu.org/hurd/mig.git
$ cd mig
$ autoreconf -i
$ mkdir build && cd build
$ ../configure --target=i686-gnu --prefix=$PREFIX
$ make -j8
$ make install

Now, before we build glibc, we should install Hurd headers similarly
to how we've installed Mach headers above:

$ git clone git://git.savannah.gnu.org/hurd/hurd.git
$ cd hurd
$ autoreconf -i
$ mkdir build && cd build
$ CC=gcc ../configure --host=i686-gnu --without-parted
--without-libcrypt --without-libbz2 --without-libz --without-rump
$ make no_deps=t prefix=$PREFIX install-headers

Now, it's finally glibc time:

$ git clone https://sourceware.org/git/glibc.git
$ mkdir build && cd build
$ ../configure --build=$(../scripts/config.guess) --host=i686-gnu
--prefix=$PREFIX --with-headers=$PREFIX/include
$ make install-headers

We also need to do some hacky things manually in order for this to
start looking enough like a real glibc installation:

$ touch $PREFIX/include/gnu/stubs.h $PREFIX/lib/libc.so
$ make csu/subdir_lib && install csu/crt1.o csu/crti.o csu/crtn.o $PREFIX/lib

Now we can go back to GCC and build libgcc:

$ make configure-target-libgcc
$ make -j8 all-target-libgcc
$ make install-target-libgcc

And now we can once again go to glibc and build it for real:

$ make PARALLELMFLAGS=-j8
$ make install

At this point it should be possible to cross-compile a C hello world
for the Hurd with no ceremony:

$ $PREFIX/bin/i686-gnu-gcc hello.c -o hello

Now we can rebuild Mach and Hurd properly, if we want to:

$ make distclean
$ ../configure --prefix=$PREFIX --host=i686-gnu
$ make -j8
$ make install

$ make distclean
$ ../configure --host=i686-gnu --without-parted --without-libcrypt
--without-libbz2 --without-libz --without-rump
$ make -j8 DESTDIR=$PREFIX install