So, you are interested in contributing to the GNU Hurd project? Welcome! Every single contribution is very much encouraged.
There are various ways to contribute; read up on contributing to...
If someone of you is lurking around here and would like to contribute, but feels she / he could do so better under formal mentoring: please contact us, or just speak up at one of the regular IRC meetings!
We also have a list of open issues and one for more elaborate project ideas - the latter originally written for the Google Summer of Code, but not exclusively. Even just investigating open issues, without being able to fix them, can be useful, because a issue that has been tracked down often becomes obvious to address for people who know the stuff -- but these people typically don't have the time that is needed to track down the issues.
This system has mostly been designed and implemented in the '90s. It works and is usable. For example, these web pages have been rendered on a GNU/Hurd system.
You can try it out for yourself: for getting access, installing Debian GNU/Hurd will probably be the easiest and most feature-complete solution. If you don't have spare hardware to use for doing so, you can also get a shell account on a public Hurd machine. Depending on the things you're going to work on (and on your internet connection), this may be an easy way of getting used to Hurd systems. Installing in a virtual machine is another possibility, see the page about running a Hurd system for the full story. In particular, running a Debian GNU/Hurd QEMU image may be a viable alternative.
Then you can either play around and eventually strive to do something useful or -- if you want -- ask us to assign something to you, depending on the skills you have and the resources you intend to invest.
Please spend some time with thinking about the items in this questionnaire.
Before you can significantly contribute to the operating system itself, you'll need to take some time to learn about the system, for example: microkernels for beginners, Mach's concepts, Hurd's concepts, the critique. Until you can understand and do the basic exercises listed there, you won't be able to significantly contribute to the Hurd.
Here is a list of small hacks, which can serve as entries into the Hurd code for people who would like to dive into the code but just lack a "somewhere to begin with".
- Make pfinet OK with the ethernet device going away. This would be a very
nice feature: being able to just restart the ethernet driver; we've just not
taken the time to fix it yet, but it shouldn't be very hard. The code begins
device_opencall, which produces
edev->ether_port. Basically, one needs to catch errors like EIEIO when using it, and in that case re-open the device.
- Add a futex kernel trap to GNU Mach. This can be useful for nicer locking
primitives, including inter-process primitives.
vm_allocatecan be used as an example in the
gnumachsource tree for how to add a kernel trap. GNU Savannah task #6231
- Add a
task_set_nameRPC to GNU Mach. Currently the Mach debugger keeps
argfrom the stack with ugly heuristics (see
looks_like_command...). It would be far better to let
execsimply set the name and record it in
thread_createcan be used as an example in the
gnumachsource tree for how to add an RPC. glibc needs to be recompiled against the updated mach.defs to get access to it from userland. exec would probably call it from
- Write a partfs translator, to which one gives a disk image, and
which exposes the partitions of the disk image, using parted, and
the parted-based storeio (
settrans -c foos1 /hurd/storeio -T typed part:1:file:/home/samy/tmp/foo). This would be libnetfs-based.
- Write virtio drivers for KVM. Ideally they would be userland.
- Port valgrind. There is a whole about this, but the basic port could be small.
- Use libz and libbz2 in exec. See
hurd/exec/unzip.cetc., they should be replaced by mere calls to libraries, GNU Savannah task #6990
vminfoalready has this kind of information, it's a matter of making procfs do the same. GNU Savannah bug #32770
Please contact us before spending a lot of time on the following porting tasks: some work may already have been done that you can base your work upon.
For guidelines, please have a look at the dedicated porting page.
There is a goal of getting Debian GNU/Hurd into shape for a technology preview/release candidate with Debian Wheezy (expected towards the end of 2012 or beginning of 2013).
The to do list is on http://wiki.debian.org/Debian_GNU/Hurd.
The following missing packages/missing functionality block a lot of other packages, and are thus good candidates for porting, in order to increase archive coverage:
- umount functionality in busybox
Here is a list of packages that need porting.
You can also just install Debian GNU/Hurd and find what doesn't work or suit you and try to improve that.
Or, you can pick one from the list of failing packages.
There is a list of open issues. This list includes everything from bug reports to open-ended research questions.
This is a very brief guide to get your development environment set up. Pester ArneBab @ irc.freenode.net on IRC if something does not work (open issue documentation)
- Install qemu-kvm via your distros packages.
- Download the qemu image:
- Unpack it:
tar xf debian-hurd.img.tar.gz
- Run it:
qemu-kvm -m 512 -no-kvm-irqchip -drive cache=writeback,index=0,media=disk,file=debian-hurd.img# …irq… is a currently necessary fix due to some changes in Linux. Optionally use
--cursesto keep your keyboard layout. If need be modprobe kvm_amd, kvm intel and kvm to get kvm support (which is much, much faster). See also: kvm FAQ.
- login as root
apt-get install -y git mercurial emacs vim
apt-get build-dep -y hurd gnumach
git clone git://git.sv.gnu.org/hurd/hurd.git
git clone git://git.sv.gnu.org/hurd/gnumach.git
git clone git://git.sv.gnu.org/hurd/incubator.git
- Get more from the repo list.
- Read the docs on these pages.
- Start hacking.
- For shutting down, use
reboot, then press
cin grub and issue halt (to avoid filesystem corruption). Adding
--no-rebootto the qemu line should help, too.
Developers have identified a number of problem with the Hurd on Mach system. Problems, that can not easily be fixed by bug-fixing the existing code base, but which require design changes -- deep going ones actually.
As such systems (as the desired one) are not in common use, but are -- if at all -- research projects, this new Hurd on a modern microkernel project itself is more a research project than a sit down and implement/code/hack project.
If you're interested in contributing in this area, knowing the Hurd on Mach system (see above) nevertheless is a prerequisite. At least have a deep look at the documentation pointers. Also read through the HurdNG section.
Please send email to the l4-hurd mailing list for discussing this post-Mach system design.
Our hackers (programmers) typically do what their kind always does: they code. What they don't like too much is documenting their wonderful achievements. On the other hand, there are people (you?) who enjoy documenting technical matters, so don't hesitate to contact us if technical documentation shall be your contribution to GNU Hurd development.
A good start is probably to just start using the Hurd, and play with the translators. In the process you will probably find that some of the documentations are missing some details, are outdated, etc. That is were you can start contributing for instance.
As an advice: do not start yet another documentation from scratch. There are already a lot of tutorials in the wilds, and they are almost all completely outdated. Rather contribute to the existing official documentation: this wiki, the documentation in the Hurd source, the Debian Hurd port pages.
Please read about how to contribute to these web pages.
Please note that doing substantial contributions to a project as big and as encompassing as the GNU Hurd is not a trivial task. For working on the GNU Hurd's inner guts and getting useful work done, you have to plan for a many-months learning experience which will need sufficient self-motivation. Working on an advanced operating system kernel isn't something you can do in a few free minutes -- even less so without any previous kernel hacking experience.
Likewise, the Linux kernel maintainers are stating the exactly same difficulties, which is well presented by Jonathan Corbet in his 2010 Linux Kernel Summit report for the opening sessions about welcoming of newcomers.
But of course, none of this is meant to be dismissive, or to scare you away -- on the contrary: just start using the GNU Hurd, and either notice yourself what's not working as expected, or have a look at one of the Open Issues, and we shall see if you'll evolve to be the next core Hurd hacker! You'll just have to get excited about it!