Gentoo/Git

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Introduction

Git is a version control system. It is used for keeping track of changes made to source code, etc. The changes are often made by different people, though this is not necessary. Similar tools include CVS, Subversion, Mercurial, or Bazaar. Git is distributed source control management system, which means it does not require a central repository. Git can and often is used with a central repository workflow, though.

Git was originally developed by Linus Torvalds and friends for managing development of the Linux kernel. It is relatively new, though many large projects have adopted it.

Installation

emerge --ask --verbose dev-vcs/git

This will install both a client and a server (disabled by default).

If you want to use gitk (visualisation tool), you should enable USE-Flag tk for dev-vcs/git.


Client Usage

  • Watch the presentation by Randal Schwartz: [1].
  • Git is documented through extensive man pages, which are replicated online. Go through the man pages: docs/.
  • Go through the everyday Git docs: [2].


Setting up a network Server

This is how to set up a server which serves read-only content.

In order to set up a server, the default location for repositories is /var/git. Here is the simplest way to do it.

Server configuration file

Make your git-daemon configuration file (in /etc/conf.d) look like this:

File: /etc/conf.d/git-daemon
# conf.d file for git-daemon
#
# Please check man 1 git-daemon for more information about the options
# git-daemon accepts. You MUST edit this to include your repositories you wish
# to serve.
#
# Some of the meaningful options are:
#   --syslog      --- Enables syslog logging
#   --verbose     --- Enables verbose logging
#   --export-all  --- Exports all repositories
#   --port=XXXX   --- Starts in port XXXX instead of 9418
#
GITDAEMON_OPTS="--syslog --enable=receive-pack --export-all --base-path=/var/git /var/git"

# To run an anonymous git safely, the following user should be able to only
# read your Git repositories. It should not able able to write to anywhere on
# your system, esp. not the repositories.
GIT_USER="nobody"
GIT_GROUP="nobody"

What that does:

  • Makes the "jail root" /var/git by specifying that at the end.
  • Allows anything that looks like a repository to be exportable with the --export-all option. If you want more limitation, please remove this option and touch a file named git-daemon-export-ok
  • Creates "virtual resources" of any repositories exported, by making the jail root prepended to all requests (git://server/blah looks for /var/git/blah).
  • It should be noticed that all the repositories have write access to all the world. Use the --enable=receive-pack carefully only in trusted LAN

Check if the /var/git directory exists (otherwise git will not start). If not

mkdir /var/git chown nobody.nobody /var/git

Then start the daemon:

/etc/init.d/git-daemon start

For some reason, it may take once or twice (it will error with !! instead of OK).

Setting up repositories

First, the daemon will be run as nobody, so become nobody:

sudo -u nobody -s

And execute all further commands in that shell.

First, create a project directory inside of the daemon's root directory (thought of as a jail root):

cd /var/git mkdir myproject

Next, put all the files in there. This is the directory which will be cloned ("checked out" in more centralized terminology).

Finally, make it into a GIT repository:
git init

If you have multiple projects, create one directory for each according to the above steps.

If clients wish to check out the project, tell them to run:

Multi User Git Server

When pushing into Git server using ssh, the ownership of the new files are associated with the user who performs the push. This does not allow other users to use the same repository. One solution is to change the default umask of a user, however, this will effect more than the Git operations.

A proper solution can be established using POSIX access control lists.

Enable ACLs in kernel, for example for ext4 filesystem, use:

Linux Kernel Configuration:
    File systems  --->
      <*> The Extended 4 (ext4) filesystem
      [*]   Ext4 extended attributes
      [*]     Ext4 POSIX Access Control Lists

Add "acl" to mount options:

File: /etc/fstab
/dev/sda3               /               ext4            noatime,acl 0 1

Create gitusers group:

groupadd gitusers

For each Git repository REPOS:

setfacl -R -d -m g:gitusers:rwX "${REPOS}"

The above will set default read and write access to gitusers groups for every file created within repository.

Now members of gitusers group can push/pull repository.

See Also

tr:Git