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diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt new file mode 100644 index 0000000000..a336ae5f6f --- /dev/null +++ b/Documentation/git-cvsserver.txt @@ -0,0 +1,433 @@ +git-cvsserver(1) +================ + +NAME +---- +git-cvsserver - A CVS server emulator for Git + +SYNOPSIS +-------- + +SSH: + +[verse] +export CVS_SERVER="git cvsserver" +'cvs' -d :ext:user@server/path/repo.git co <HEAD_name> + +pserver (/etc/inetd.conf): + +[verse] +cvspserver stream tcp nowait nobody /usr/bin/git-cvsserver git-cvsserver pserver + +Usage: + +[verse] +'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 linkgit: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 +<<dbbackend,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 linkgit:gitcvs-migration[7]. + +[[configaccessmethod]] +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 +------ + +[[dbbackend]] +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 can not 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 <<configaccessmethod,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. + +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 linkgit: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 linkgit:git[1] suite |