Giacomo Tesio
b862596737
In Plan9 the create syscall fallback on a open(OTRUNC) if the path provided already exists. This is actually a common requirement as most programs (editors, cat...) simply requires that a file is there and is empty, and doesn't care overwriting existing contents (note that this is particularily sensible with something like fossil). In Jehanne the application is responsible of actually handle this "file exists" error but libc provides ocreate() to mimic the Plan9 behaviour. Note that ocreate introduce a subtle race too: the path is walked several times if the file exists, thus it could misbehave on concurrent namespace changes. However I guess this is not going to happen often enough to care now. NOTE we will probably address this rare race too, with a more drammatic change to syscalls: a new walk() syscall that will provide an unopen fd. |
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|---|---|---|
| arch | ||
| cfg | ||
| doc/license | ||
| hacking@285f3026b0 | ||
| lib | ||
| mnt | ||
| pkgs | ||
| qa | ||
| sys | ||
| tmp | ||
| usr/glenda | ||
| .gitignore | ||
| .gitmodules | ||
| .travis.yml | ||
| build.json | ||
| LICENSE.md | ||
| README.md | ||
Jehanne
Jehanne is a simple operating system.
Jehanne has noble ancestors:
- most of userland tools, a lot of wisdom and some kernel modules, come from 9front
- the kernel is a fork of Charles Forsyth's Plan9-9k
- most of the build system and some valuable piece of code come from Harvey OS
Still the project is named after a humble peasant, the famous French heretic Joan of Arc, because it diverges deeply from the design and conventions of its predecessors.
Overview
This is the main repository, used to build the system as a whole:
- arch contains one folder for each supported architecture, with specific C headers, libraries and executables (note that by architecture we intend any kind of physical or virtual machine that is able to run code, thus rc is actually an architecture)
- sys is the system folder
- doc contains useful documentation for Jehanne development
- hacking contains the utilities used to develop Jehanne
- qa contains the regression tests
- mnt contains default mount targets
- usr contains the users' folders
- pkgs will contains the installed packages
The running system also includes supplemental folders like /lib,
/cmd and /dev that are bound during the boot as required.
Build
To build Jehanne and play with it, you need to have git, golang, qemu, gcc, binutils and bison installed. For example on Debian GNU/Linux you should be able to get going with
sudo aptitude install git golang build-essential bison qemu-system
After the repository clone, you can give a look with
git submodule init # we have a lot of submodules
git submodule update --init --recursive --remote
./hacking/devshell.sh # start a shell with appropriate environment
./hacking/continuous-build.sh # to build everything (will take a while)
./hacking/runOver9P.sh # to start the system in QEMU
./hacking/drawterm.sh # to connect Jehanne with drawterm
Hacking
Jehanne is a work in progress. Forks and pull requests are welcome.
In doc/hacking you will find all you need to know about its principles, design and weirdness.
There's a lot of work to do, in every area of the system.
To coordinate our efforts, we use the github issues. To discuss (and even debate) about the design and development of Jehanne we use the JehanneOS mailing list: please join and present yourself and your attitudes.