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git-cvsserver

NAME

git-cvsserver - A CVS server emulator for git

SYNOPSIS

export CVS_SERVER=git-cvsserver

cvs -d :ext:user@server/path/repo.git co <HEAD_name>

DESCRIPTION

This application is a CVS emulation layer for git.

It is highly functional. However, not all methods are implemented, and for those methods that are implemented, not all switches are implemented.

Testing has been done using both the CLI CVS client, and the Eclipse CVS plugin. Most functionality works fine with both of these clients.

LIMITATIONS

Currently cvsserver works over SSH connections for read/write clients, and over pserver for anonymous CVS access.

CVS clients cannot tag, branch or perform GIT merges.

git-cvsserver maps GIT branches to CVS modules. This is very different from what most CVS users would expect since in CVS modules usually represent one or more directories.

INSTALLATION

1.If you are going to offer anonymous CVS access via pserver, add a line in /etc/inetd.conf like

   cvspserver stream tcp nowait nobody git-cvsserver pserver

Note: Some inetd servers let you specify the name of the executable independently of the value of argv[0] (i.e. the name the program assumes it was executed with). In this case the correct line in /etc/inetd.conf looks like

   cvspserver stream tcp nowait nobody /usr/bin/git-cvsserver git-cvsserver pserver

No special setup is needed for SSH access, other than having GIT tools in the PATH. If you have clients that do not accept the CVS_SERVER environment variable, you can rename git-cvsserver to cvs.

Note: Newer cvs versions (>= 1.12.11) also support specifying CVS_SERVER directly in CVSROOT like

cvs -d ":ext;CVS_SERVER=git-cvsserver:user@server/path/repo.git" co <HEAD_name>

This has the advantage that it will be saved in your CVS/Root files and you don't need to worry about always setting the correct environment variable.

2.For each repo that you want accessible from CVS you need to edit config in the repo and add the following section.

   [gitcvs]

        enabled=1

        # optional for debugging

        logfile=/path/to/logfile

Note: you need to ensure each user that is going to invoke git-cvsserver has write access to the log file and to the database (see Database Backend. If you want to offer write access over SSH, the users of course also need write access to the git repository itself.

All configuration variables can also be overridden for a specific method of access. Valid method names are "ext" (for SSH access) and "pserver". The following example configuration would disable pserver access while still allowing access over SSH.

   [gitcvs]

        enabled=0



   [gitcvs "ext"]

        enabled=1

3.On the client machine you need to set the following variables. CVSROOT should be set as per normal, but the directory should point at the appropriate git repo. For example:
For SSH access, CVS_SERVER should be set to git-cvsserver
Example:

     export CVSROOT=:ext:user@server:/var/git/project.git

     export CVS_SERVER=git-cvsserver

4.For SSH clients that will make commits, make sure their .bashrc file sets the GIT_AUTHOR and GIT_COMMITTER variables.

5.Clients should now be able to check out the project. Use the CVS module name to indicate what GIT head you want to check out. Example:

     cvs co -d project-master master

DATABASE BACKEND

git-cvsserver uses one database per git head (i.e. CVS module) to store information about the repository for faster access. The database doesn't contain any persistent data and can be completely regenerated from the git repository at any time. The database needs to be updated (i.e. written to) after every commit.

If the commit is done directly by using git (as opposed to using git-cvsserver) the update will need to happen on the next repository access by git-cvsserver, independent of access method and requested operation.

That means that even if you offer only read access (e.g. by using the pserver method), git-cvsserver should have write access to the database to work reliably (otherwise you need to make sure that the database if up-to-date all the time git-cvsserver is run).

By default it uses SQLite databases in the git directory, named gitcvs.<module_name>.sqlite. Note that the SQLite backend creates temporary files in the same directory as the database file on write so it might not be enough to grant the users using git-cvsserver write access to the database file without granting them write access to the directory, too.

You can configure the database backend with the following configuration variables:

Configuring database backend

git-cvsserver uses the Perl DBI module. Please also read its documentation if changing these variables, especially about DBI->connect().

gitcvs.dbname

Database name. The exact meaning depends on the used database driver, for SQLite this is a filename. Supports variable substitution (see below). May not contain semicolons (;). Default: %Ggitcvs.%m.sqlite

gitcvs.dbdriver

Used DBI driver. You can specify any available driver for this here, but it might not work. cvsserver is tested with DBD::SQLite, reported to work with DBD::Pg, and reported not to work with DBD::mysql. Please regard this as an experimental feature. May not contain double colons (:). Default: SQLite

gitcvs.dbuser

Database user. Only useful if setting dbdriver, since SQLite has no concept of database users. Supports variable substitution (see below).

gitcvs.dbpass

Database password. Only useful if setting dbdriver, since SQLite has no concept of database passwords.

All variables can also be set per access method, see above.

Variable substitution

In dbdriver and dbuser you can use the following variables:
%G

git directory name

%g

git directory name, where all characters except for alpha-numeric ones, ., and - are replaced with _ (this should make it easier to use the directory name in a filename if wanted)

%m

CVS module/git head name

%a

access method (one of "ext" or "pserver")

%u

Name of the user running git-cvsserver. If no name can be determined, the numeric uid is used.

ECLIPSE CVS CLIENT NOTES

To get a checkout with the Eclipse CVS client:

1.Select "Create a new project -> From CVS checkout"

2.Create a new location. See the notes below for details on how to choose the right protocol.

3.Browse the modules available. It will give you a list of the heads in the repository. You will not be able to browse the tree from there. Only the heads.

4.Pick HEAD when it asks what branch/tag to check out. Untick the "launch commit wizard" to avoid committing the .project file.

Protocol notes: If you are using anonymous access via pserver, just select that. Those using SSH access should choose the ext protocol, and configure ext access on the Preferences->Team->CVS->ExtConnection pane. Set CVS_SERVER to git-cvsserver. Note that password support is not good when using ext, you will definitely want to have SSH keys setup.

Alternatively, you can just use the non-standard extssh protocol that Eclipse offer. In that case CVS_SERVER is ignored, and you will have to replace the cvs utility on the server with git-cvsserver or manipulate your .bashrc so that calling cvs effectively calls git-cvsserver.

CLIENTS KNOWN TO WORK

*CVS 1.12.9 on Debian

*CVS 1.11.17 on MacOSX (from Fink package)

*Eclipse 3.0, 3.1.2 on MacOSX (see Eclipse CVS Client Notes)

*TortoiseCVS

OPERATIONS SUPPORTED

All the operations required for normal use are supported, including checkout, diff, status, update, log, add, remove, commit. Legacy monitoring operations are not supported (edit, watch and related). Exports and tagging (tags and branches) are not supported at this stage.

The server should set the -k mode to binary when relevant, however, this is not really implemented yet. For now, you can force the server to set -kb for all files by setting the gitcvs.allbinary config variable. In proper GIT tradition, the contents of the files are always respected. No keyword expansion or newline munging is supported.

DEPENDENCIES

git-cvsserver depends on DBD::SQLite.

COPYRIGHT AND AUTHORS

This program is copyright The Open University UK - 2006.

Authors:

*Martyn Smith <martyn@catalyst.net.nz>

*Martin Langhoff <martin@catalyst.net.nz>

with ideas and patches from participants of the git-list <git@vger.kernel.org>.

DOCUMENTATION

Documentation by Martyn Smith <martyn@catalyst.net.nz>, Martin Langhoff <martin@catalyst.net.nz>, and Matthias Urlichs <smurf@smurf.noris.de>.

GIT

Part of the git(7) suite