git-cvsserver

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> ...]


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>
           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.

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
       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 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:

                  [gitcvs]
                       authdb = /etc/cvsserver/passwd

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

                  myuser:$1Oyx5r9mdGZ2
                  myuser:$1$BA)@$vbnMJMDym7tA32AamXrm./

           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 option.

           Alternatively you can produce the password with perl’s crypt()
           operator:

                  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 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 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.

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.

       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 2.30.0                         12/28/2020                   GIT-CVSSERVER(1)