Merge branch 'fl/cvsserver'

* fl/cvsserver:
  config.txt: Add gitcvs.db* variables
  cvsserver: Document the GIT branches -> CVS modules mapping more prominently
  cvsserver: Reword documentation on necessity of write access
  cvsserver: Allow to "add" a removed file
  cvsserver: Add asciidoc documentation for new database backend configuration
  cvsserver: Corrections to the database backend configuration
  cvsserver: Use DBI->table_info instead of DBI->tables
  cvsserver: Abort if connect to database fails
  cvsserver: Make the database backend configurable
  cvsserver: Allow to override the configuration per access method
  cvsserver: Handle three part keys in git config correctly
  cvsserver: Introduce new state variable 'method'

Conflicts:

	Documentation/config.txt

2 files changed, 130 insertions, 3 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 7e41ca6a0d..2c0a666323 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -423,8 +423,34 @@ gitcvs.allbinary::
 	causes the client to treat all files as binary files which suppresses
 	any newline munging it otherwise might do. A work-around for the
 	fact that there is no way yet to set single files to mode '-kb'.
+
+gitcvs.dbname::
+	Database used by git-cvsserver to cache revision information
+	derived from the git repository. The exact meaning depends on the
+	used database driver, for SQLite (which is the default driver) this
+	is a filename. Supports variable substitution (see
+	gitlink:git-cvsserver[1] for details). May not contain semicolons (`;`).
+	Default: '%Ggitcvs.%m.sqlite'
+
+gitcvs.dbdriver::
+	Used Perl DBI driver. You can specify any available driver
+        for this here, but it might not work. git-cvsserver is tested
+	with 'DBD::SQLite', reported to work with 'DBD::Pg', and
+	reported *not* to work with 'DBD::mysql'. Experimental feature.
+	May not contain double colons (`:`). Default: 'SQLite'.
 	See gitlink:git-cvsserver[1].
 
+gitcvs.dbuser, gitcvs.dbpass::
+	Database user and password. Only useful if setting 'gitcvs.dbdriver',
+	since SQLite has no concept of database users and/or passwords.
+	'gitcvs.dbuser' supports variable substitution (see
+	gitlink:git-cvsserver[1] for details).
+
+All gitcvs variables except for 'gitcvs.allbinary' can also specifed
+as 'gitcvs.<access_method>.<varname>' (where 'access_method' is one
+of "ext" and "pserver") to make them apply only for the given access
+method.
+
 http.sslVerify::
 	Whether to verify the SSL certificate when fetching or pushing
 	over HTTPS. Can be overridden by the 'GIT_SSL_NO_VERIFY' environment
diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt
index f9e0c77379..d22844ba49 100644
--- a/Documentation/git-cvsserver.txt
+++ b/Documentation/git-cvsserver.txt
@@ -31,6 +31,10 @@ 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
 ------------
 
@@ -65,9 +69,22 @@ env variable, you can rename git-cvsserver to cvs.
 
 ------
 Note: you need to ensure each user that is going to invoke git-cvsserver has
-write access to the log file and to the git repository. When offering anon
-access via pserver, this means that the nobody user should have write access
-to at least the sqlite database at the root of the repository.
+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.
+
+[[configaccessmethod]]
+All configuration variables can also be overriden 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
@@ -93,6 +110,90 @@ Example:
      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 for faster access. The
+database doesn't contain any persitent data and can be completly
+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 <<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.
+
 Eclipse CVS Client Notes
 ------------------------