GIT-CVSSERVER(1) Git Manual GIT-CVSSERVER(1)

NAME

git-cvsserver - A CVS server emulator for Git

SYNOPSIS

SSH:

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

pserver (/etc/inetd.conf):

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

Usage:

git-cvsserver [<options>] [pserver|server] [<directory> ...]

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.

OPTIONS

All these options obviously only make sense if enforced by the server
side. They have been implemented to resemble the git-daemon(1)
options as closely as possible.

--base-path <path>
Prepend path to requested CVSROOT

--strict-paths
Don't allow recursing into subdirectories

--export-all
Don't check for gitcvs.enabled in config. You also have to
specify a list of allowed directories (see below) if you want to
use this option.

-V, --version
Print version information and exit

-h, -H, --help
Print usage information and exit

<directory>
The remaining arguments provide a list of directories. If no
directories are given, then all are allowed. Repositories within
these directories still require the gitcvs.enabled config option,
unless --export-all is specified.

LIMITATIONS

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 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

Only anonymous access is provided by pserver by default. To
commit you will have to create pserver accounts, simply add a
gitcvs.authdb setting in the config file of the repositories you
want the cvsserver to allow writes to, for example:

[gitcvs]
authdb = /etc/cvsserver/passwd

The format of these files is username followed by the encrypted
password, for example:

myuser:sqkNi8zPf01HI
myuser:$1$9K7FzU28$VfF6EoPYCJEYcVQwATgOP/
myuser:$5$.NqmNH1vwfzGpV8B$znZIcumu1tNLATgV2l6e1/mY8RzhUDHMOaVOeL1cxV3

You can use the htpasswd facility that comes with Apache to make
these files, but only with the -d option (or -B if your system
supports it).

Preferably use the system specific utility that manages password
hash creation in your platform (e.g. mkpasswd in Linux, encrypt
in OpenBSD or pwhash in NetBSD) and paste it in the right
location.

Then provide your password via the pserver method, for example:

cvs -d:pserver:someuser:somepassword@server:/path/repo.git co <HEAD_name>

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. SSH users restricted to git-shell
don't need to override the default with CVS_SERVER (and
shouldn't) as git-shell understands cvs to mean git-cvsserver and
pretends that the other end runs the real cvs better.

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.

You also need to ensure that each repository is "bare" (without a
Git index file) for cvs commit to work. See gitcvs-migration(7).

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. If you didn't specify the CVSROOT/CVS_SERVER directly in the
checkout command, automatically saving it in your CVS/Root files,
then you need to set them explicitly in your environment. CVSROOT
should be set as per normal, but the directory should point at
the appropriate Git repo. As above, for SSH clients not
restricted to git-shell, CVS_SERVER should be set to
git-cvsserver.

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
server-side .ssh/environment files (or .bashrc, etc., according
to their specific shell) export appropriate values for
GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, GIT_COMMITTER_NAME, and
GIT_COMMITTER_EMAIL. For SSH clients whose login shell is bash,
.bashrc may be a reasonable alternative.

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. This
also sets the name of your newly checked-out directory, unless
you tell it otherwise with -d <dir-name>. For example, this
checks out master branch to the project-master directory:

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 to maintain consistent CVS
revision numbers. 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 is up to date any time git-cvsserver is executed).

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.

The database cannot be reliably regenerated in a consistent form
after the branch it is tracking has changed. Example: For merged
branches, git-cvsserver only tracks one branch of development, and
after a git merge an incrementally updated database may track a
different branch than a database regenerated from scratch, causing
inconsistent CVS revision numbers. git-cvsserver has no way of
knowing which branch it would have picked if it had been run
incrementally pre-merge. So if you have to fully or partially (from
old backup) regenerate the database, you should be suspicious of
pre-existing CVS sandboxes.

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 selected 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 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.

gitcvs.dbTableNamePrefix
Database table name prefix. Supports variable substitution (see
below). Any non-alphabetic characters will be replaced with
underscores.

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
alphanumeric 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.

ENVIRONMENT

These variables obviate the need for command-line options in some
circumstances, allowing easier restricted usage through git-shell.

GIT_CVSSERVER_BASE_PATH
This variable replaces the argument to --base-path.

GIT_CVSSERVER_ROOT
This variable specifies a single directory, replacing the
<directory>... argument list. The repository still requires the
gitcvs.enabled config option, unless --export-all is specified.

When these environment variables are set, the corresponding
command-line arguments may not be 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

+o CVS 1.12.9 on Debian

+o CVS 1.11.17 on MacOSX (from Fink package)

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

+o TortoiseCVS

OPERATIONS SUPPORTED

All the operations required for normal use are supported, including
checkout, diff, status, update, log, add, remove, commit.

Most CVS command arguments that read CVS tags or revision numbers
(typically -r) work, and also support any git refspec (tag, branch,
commit ID, etc). However, CVS revision numbers for non-default
branches are not well emulated, and cvs log does not show tags or
branches at all. (Non-main-branch CVS revision numbers superficially
resemble CVS revision numbers, but they actually encode a git commit
ID directly, rather than represent the number of revisions since the
branch point.)

Note that there are two ways to checkout a particular branch. As
described elsewhere on this page, the "module" parameter of cvs
checkout is interpreted as a branch name, and it becomes the main
branch. It remains the main branch for a given sandbox even if you
temporarily make another branch sticky with cvs update -r.
Alternatively, the -r argument can indicate some other branch to
actually checkout, even though the module is still the "main" branch.
Tradeoffs (as currently implemented): Each new "module" creates a new
database on disk with a history for the given module, and after the
database is created, operations against that main branch are fast. Or
alternatively, -r doesn't take any extra disk space, but may be
significantly slower for many operations, like cvs update.

If you want to refer to a git refspec that has characters that are
not allowed by CVS, you have two options. First, it may just work to
supply the git refspec directly to the appropriate CVS -r argument;
some CVS clients don't seem to do much sanity checking of the
argument. Second, if that fails, you can use a special character
escape mechanism that only uses characters that are valid in CVS
tags. A sequence of 4 or 5 characters of the form (underscore ("_"),
dash ("-"), one or two characters, and dash ("-")) can encode various
characters based on the one or two letters: "s" for slash ("/"), "p"
for period ("."), "u" for underscore ("_"), or two hexadecimal digits
for any byte value at all (typically an ASCII number, or perhaps a
part of a UTF-8 encoded character).

Legacy monitoring operations are not supported (edit, watch and
related). Exports and tagging (tags and branches) are not supported
at this stage.

CRLF Line Ending Conversions

By default the server leaves the -k mode blank for all files, which
causes the CVS client to treat them as a text files, subject to
end-of-line conversion on some platforms.

You can make the server use the end-of-line conversion attributes to
set the -k modes for files by setting the gitcvs.usecrlfattr config
variable. See gitattributes(5) for more information about end-of-line
conversion.

Alternatively, if gitcvs.usecrlfattr config is not enabled or the
attributes do not allow automatic detection for a filename, then the
server uses the gitcvs.allBinary config for the default setting. If
gitcvs.allBinary is set, then file not otherwise specified will
default to -kb mode. Otherwise the -k mode is left blank. But if
gitcvs.allBinary is set to "guess", then the correct -k mode will be
guessed based on the contents of the file.

For best consistency with cvs, it is probably best to override the
defaults by setting gitcvs.usecrlfattr to true, and gitcvs.allBinary
to "guess".

DEPENDENCIES

git-cvsserver depends on DBD::SQLite.

GIT

Part of the git(1) suite

Git 2.48.1 2025-01-13 GIT-CVSSERVER(1)