Additional to the following text, a further [[example]] has be posted.

/!\ The following information may very well be incomplete and out-dated.


# Building the Hurd from Source

If you want to build the Hurd libraries and servers (translators) yourself
instead of just using pre-built binaries, follow these instructions.

One note before we begin: the likelihood that the compiled result will actually
do what you expect it to do is the highest if you try building from the Debian
source packages.  This is especially true if you want to use your compilation
within a Debian system.

Note that for building code to run on GNU/Hurd systems, you need a toolchain
for the GNU Hurd.  You can either compile on a GNU/Hurd system, or need a
cross-compiler targeting GNU/Hurd.  Our [[toolchain page|toolchain]] has the
details.


## Getting the Source Code

You can chose between getting the [sources from the developers's
git](http://savannah.gnu.org/git/?group=hurd):

    $ git clone git://git.sv.gnu.org/hurd/hurd.git

... or (if you are working on a Debian system) the ones that are used for the
[current Debian hurd package](http://packages.debian.net/source/unstable/hurd):

    $ apt-get source hurd

Please see the Debian [[running/debian/FAQ]] before using `apt-get source`.

The unpacked source tree is around 20 MiB, and the build tree (configured with
`--disable-profile`) is around 100 MiB.

## Preparing for the Build

### ... on Debian systems

Building the Hurd requires the *build-essential* and *fakeroot* packages, their
dependencies and additional packages that are specified by the source hurd
package:

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

### ... on non-Debian systems

[TODO]

## Building

### Debian `.deb` Files

Change into the directory with the downloaded / unpacked Hurd sources, e.g.

    $ cd hurd-[TODO]

If you want to work on the sources before building them, it's advisable to
first apply the patches the Debian hurd package additionally contains:

    $ debian/rules apply-patches

Then edit and change whatever files you want and finally start the build
process with

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

The `.deb` packages will then drop out at the `../` directory.

### Building, but not the Debian Way

The Hurd has to be built in a separate directory:

    $ mkdir hurd-build
    $ cd hurd-build

    $ [...]/hurd-[TODO]/configure --disable-profile
    $ make
    $ make install

Notice that `make install` will install the Hurd in `/`, not in `/usr/local/`
or `/local/`, so your current Hurd servers will be replaced.  [TODO: how to
install somewhere else.]

By default profiling versions of all the libraries and code are generated but
this is useless in most of the cases, so we disable them by specifying
`--disable-profile` on `configure`'s command line.

If you just want to build a specific server or library, you can pass its name
to `make`:

    $ make ext2fs
    $ make libtrivfs

This will automatically build all libraries that are required to build the
requested server or library.


## RPC IDs

[TODO: update / integrate somewhere.]

If you want to trace the RPC calls made by some process by using `rpctrace`
command, you will also want some more human-readable output of this
command. This is achieved by generating `hurd.msgids` file that includes the
mapping between the number of the RPC call and its name:

    $ cd build/hurd
    $ make hurd.msgids
    $ cp hurd.msgids ~

Now you can use this file in the following way:

    $ rpctrace -i ~/hurd.msgids ls