Building GNU Mach from Source

If you want to build the GNU Mach kernel yourself instead of just using a pre-built binary, follow these instructions.

The unpacked source tree is around 20 MiB, and the build tree (with all drivers enabled) is around 50 MiB.

Getting the Source Code

You can either use the git repository (see,

$ git clone

... or get the Debian sources, if you're using Debian. (See here.)

$ apt-get source gnumach

On Debian Systems:

Preparing for the Build

Building GNU Mach requires the build-essential and fakeroot packages, and some additional dependencies specified by the gnumach source package:

# apt-get install build-essential fakeroot
# apt-get build-dep gnumach

Building and Installing ... Debian .deb files

Change into the directory with the downloaded / unpacked GNU Mach sources,

$ cd gnumach-XXXXXXXX

Start the build process with

$ dpkg-buildpackage -us -uc -b -rfakeroot

GNU Mach is now building. To use the new kernel, you must install the resulting .deb package which is located one directory above the build directory and has a similar name as the build directory:

# dpkg -i ../gnumach_XXXXXXXX-X_hurd-i386.deb

You can now reboot your computer and enjoy the new kernel.

On non-Debian Systems:

Preparing for the Build

Building GNU Mach requires a C compiler, a static 32 bit standard C library, your favourite flavor of awk (gawk) and GNU make.

First, create the configuration files:

$ cd gnumach
$ autoreconf --install

GNU Mach (and the associated headers) need be built in a separate build directory:

$ mkdir build
$ cd build

Run configure:

$ ../configure --prefix=

If building on a 64 bit host system, you need a number of additional settings to force a 32 bit build:

$ CPP='gcc -m32 -E -x c -undef -ansi' CC='gcc -m32' LD='ld -melf_i386' ../configure --prefix= --host=i686-unknown-linux-gnu

Installing the Header Files First

In order to build GNU Mach, you will need a working MIG. Building MIG in turn requires the GNU Mach header files to be already present. So for bootstrapping MIG, you have to install the Mach headers first, for example into ~/gnu/include/:

$ make DESTDIR=~/gnu install-data

Now you can build MIG. Once you are done with that, come back here to finish the Mach build.

Building and Installing

With MIG present, now build the kernel image:

$ make gnumach.gz

Optionally run the (tiny) test suite:

$ make check

It's a good idea to make a backup of the previously installed kernel, in case you can't boot using the new one. That way, you can restore it after booting from a rescue media (or mounting the disk image used by your vm).

# cp /boot/gnumach.gz /boot/gnumach.gz.bak

GNU Mach can now be moved into place, typically /boot/gnumach.gz, so that you can boot your system with the new kernel.

# cp gnumach.gz /boot