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Updated: Wednesday, February 9, 2022

git-cvsserver (1)


git-cvsserver - A CVS server emulator for Git



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


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


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

       git-cvsserver - A CVS server emulator for Git


       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


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

       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

           Don't allow recursing into subdirectories

           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

       -V, --version
           Print version information and exit

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

           You can specify a list of allowed directories. If no directories
           are given, all are allowed. This is an additional restriction,
           gitcvs access still needs to be enabled by the gitcvs.enabled
           config option unless --export-all was given, too.

       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

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

       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.

        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 pserve 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:

                       authdb = /etc/cvsserver/passwd

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


           You can use the htpasswd facility that comes with Apache to make
           these files, but Apache's MD5 crypt method differs from the one
           used by most C library's crypt() function, so don't use the -m

           Alternatively you can produce the password with perl's crypt()

                  perl -e 'my ($user, $pass) = @ARGV; printf "%s:%s\n", $user, crypt($user, $pass)' $USER password

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

                  cvs -d:pserver:someuser:somepassword <at> 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

           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.

                       # optional for debugging

           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

           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 "ext"]

        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,
           SSH clients whose login shell is bash, .bashrc may be a reasonable

        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

       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

       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

       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

   Configuring database backend
       git-cvsserver uses the Perl DBI module. Please also read its
       documentation if changing these variables, especially about

           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:

           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

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

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

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

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

       Variable substitution
           In dbDriver and dbUser you can use the following variables:

               Git directory name

               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

               CVS module/Git head name

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

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

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

       GIT_CVSSERVER_BASE_PATH takes the place of the argument to --base-path.

       GIT_CVSSERVER_ROOT specifies a single-directory whitelist. The
       repository must still be configured to allow access through
       git-cvsserver, as described above.

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

       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.

       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

       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

       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

       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

       git-cvsserver depends on DBD::SQLite.

       Part of the git(1) suite

Git 2.31.1                        03/26/2021                  GIT-CVSSERVER(1)