merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 277 insertions, 0 deletions

diff --git a/third_party/git/Documentation/git-http-backend.txt b/third_party/git/Documentation/git-http-backend.txt
new file mode 100644
index 000000000000..558966aa8379
--- /dev/null
+++ b/third_party/git/Documentation/git-http-backend.txt
@@ -0,0 +1,277 @@
+git-http-backend(1)
+===================
+
+NAME
+----
+git-http-backend - Server side implementation of Git over HTTP
+
+SYNOPSIS
+--------
+[verse]
+'git http-backend'
+
+DESCRIPTION
+-----------
+A simple CGI program to serve the contents of a Git repository to Git
+clients accessing the repository over http:// and https:// protocols.
+The program supports clients fetching using both the smart HTTP protocol
+and the backwards-compatible dumb HTTP protocol, as well as clients
+pushing using the smart HTTP protocol.
+
+It verifies that the directory has the magic file
+"git-daemon-export-ok", and it will refuse to export any Git directory
+that hasn't explicitly been marked for export this way (unless the
+`GIT_HTTP_EXPORT_ALL` environmental variable is set).
+
+By default, only the `upload-pack` service is enabled, which serves
+'git fetch-pack' and 'git ls-remote' clients, which are invoked from
+'git fetch', 'git pull', and 'git clone'.  If the client is authenticated,
+the `receive-pack` service is enabled, which serves 'git send-pack'
+clients, which is invoked from 'git push'.
+
+SERVICES
+--------
+These services can be enabled/disabled using the per-repository
+configuration file:
+
+http.getanyfile::
+	This serves Git clients older than version 1.6.6 that are unable to use the
+	upload pack service.  When enabled, clients are able to read
+	any file within the repository, including objects that are
+	no longer reachable from a branch but are still present.
+	It is enabled by default, but a repository can disable it
+	by setting this configuration item to `false`.
+
+http.uploadpack::
+	This serves 'git fetch-pack' and 'git ls-remote' clients.
+	It is enabled by default, but a repository can disable it
+	by setting this configuration item to `false`.
+
+http.receivepack::
+	This serves 'git send-pack' clients, allowing push.  It is
+	disabled by default for anonymous users, and enabled by
+	default for users authenticated by the web server.  It can be
+	disabled by setting this item to `false`, or enabled for all
+	users, including anonymous users, by setting it to `true`.
+
+URL TRANSLATION
+---------------
+To determine the location of the repository on disk, 'git http-backend'
+concatenates the environment variables PATH_INFO, which is set
+automatically by the web server, and GIT_PROJECT_ROOT, which must be set
+manually in the web server configuration.  If GIT_PROJECT_ROOT is not
+set, 'git http-backend' reads PATH_TRANSLATED, which is also set
+automatically by the web server.
+
+EXAMPLES
+--------
+All of the following examples map `http://$hostname/git/foo/bar.git`
+to `/var/www/git/foo/bar.git`.
+
+Apache 2.x::
+	Ensure mod_cgi, mod_alias, and mod_env are enabled, set
+	GIT_PROJECT_ROOT (or DocumentRoot) appropriately, and
+	create a ScriptAlias to the CGI:
++
+----------------------------------------------------------------
+SetEnv GIT_PROJECT_ROOT /var/www/git
+SetEnv GIT_HTTP_EXPORT_ALL
+ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
+----------------------------------------------------------------
++
+To enable anonymous read access but authenticated write access,
+require authorization for both the initial ref advertisement (which we
+detect as a push via the service parameter in the query string), and the
+receive-pack invocation itself:
++
+----------------------------------------------------------------
+RewriteCond %{QUERY_STRING} service=git-receive-pack [OR]
+RewriteCond %{REQUEST_URI} /git-receive-pack$
+RewriteRule ^/git/ - [E=AUTHREQUIRED:yes]
+
+<LocationMatch "^/git/">
+	Order Deny,Allow
+	Deny from env=AUTHREQUIRED
+
+	AuthType Basic
+	AuthName "Git Access"
+	Require group committers
+	Satisfy Any
+	...
+</LocationMatch>
+----------------------------------------------------------------
++
+If you do not have `mod_rewrite` available to match against the query
+string, it is sufficient to just protect `git-receive-pack` itself,
+like:
++
+----------------------------------------------------------------
+<LocationMatch "^/git/.*/git-receive-pack$">
+	AuthType Basic
+	AuthName "Git Access"
+	Require group committers
+	...
+</LocationMatch>
+----------------------------------------------------------------
++
+In this mode, the server will not request authentication until the
+client actually starts the object negotiation phase of the push, rather
+than during the initial contact.  For this reason, you must also enable
+the `http.receivepack` config option in any repositories that should
+accept a push. The default behavior, if `http.receivepack` is not set,
+is to reject any pushes by unauthenticated users; the initial request
+will therefore report `403 Forbidden` to the client, without even giving
+an opportunity for authentication.
++
+To require authentication for both reads and writes, use a Location
+directive around the repository, or one of its parent directories:
++
+----------------------------------------------------------------
+<Location /git/private>
+	AuthType Basic
+	AuthName "Private Git Access"
+	Require group committers
+	...
+</Location>
+----------------------------------------------------------------
++
+To serve gitweb at the same url, use a ScriptAliasMatch to only
+those URLs that 'git http-backend' can handle, and forward the
+rest to gitweb:
++
+----------------------------------------------------------------
+ScriptAliasMatch \
+	"(?x)^/git/(.*/(HEAD | \
+			info/refs | \
+			objects/(info/[^/]+ | \
+				 [0-9a-f]{2}/[0-9a-f]{38} | \
+				 pack/pack-[0-9a-f]{40}\.(pack|idx)) | \
+			git-(upload|receive)-pack))$" \
+	/usr/libexec/git-core/git-http-backend/$1
+
+ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/
+----------------------------------------------------------------
++
+To serve multiple repositories from different linkgit:gitnamespaces[7] in a
+single repository:
++
+----------------------------------------------------------------
+SetEnvIf Request_URI "^/git/([^/]*)" GIT_NAMESPACE=$1
+ScriptAliasMatch ^/git/[^/]*(.*) /usr/libexec/git-core/git-http-backend/storage.git$1
+----------------------------------------------------------------
+
+Accelerated static Apache 2.x::
+	Similar to the above, but Apache can be used to return static
+	files that are stored on disk.  On many systems this may
+	be more efficient as Apache can ask the kernel to copy the
+	file contents from the file system directly to the network:
++
+----------------------------------------------------------------
+SetEnv GIT_PROJECT_ROOT /var/www/git
+
+AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$          /var/www/git/$1
+AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
+ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
+----------------------------------------------------------------
++
+This can be combined with the gitweb configuration:
++
+----------------------------------------------------------------
+SetEnv GIT_PROJECT_ROOT /var/www/git
+
+AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$          /var/www/git/$1
+AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
+ScriptAliasMatch \
+	"(?x)^/git/(.*/(HEAD | \
+			info/refs | \
+			objects/info/[^/]+ | \
+			git-(upload|receive)-pack))$" \
+	/usr/libexec/git-core/git-http-backend/$1
+ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/
+----------------------------------------------------------------
+
+Lighttpd::
+	Ensure that `mod_cgi`, `mod_alias`, `mod_auth`, `mod_setenv` are
+	loaded, then set `GIT_PROJECT_ROOT` appropriately and redirect
+	all requests to the CGI:
++
+----------------------------------------------------------------
+alias.url += ( "/git" => "/usr/lib/git-core/git-http-backend" )
+$HTTP["url"] =~ "^/git" {
+	cgi.assign = ("" => "")
+	setenv.add-environment = (
+		"GIT_PROJECT_ROOT" => "/var/www/git",
+		"GIT_HTTP_EXPORT_ALL" => ""
+	)
+}
+----------------------------------------------------------------
++
+To enable anonymous read access but authenticated write access:
++
+----------------------------------------------------------------
+$HTTP["querystring"] =~ "service=git-receive-pack" {
+	include "git-auth.conf"
+}
+$HTTP["url"] =~ "^/git/.*/git-receive-pack$" {
+	include "git-auth.conf"
+}
+----------------------------------------------------------------
++
+where `git-auth.conf` looks something like:
++
+----------------------------------------------------------------
+auth.require = (
+	"/" => (
+		"method" => "basic",
+		"realm" => "Git Access",
+		"require" => "valid-user"
+	       )
+)
+# ...and set up auth.backend here
+----------------------------------------------------------------
++
+To require authentication for both reads and writes:
++
+----------------------------------------------------------------
+$HTTP["url"] =~ "^/git/private" {
+	include "git-auth.conf"
+}
+----------------------------------------------------------------
+
+
+ENVIRONMENT
+-----------
+'git http-backend' relies upon the `CGI` environment variables set
+by the invoking web server, including:
+
+* PATH_INFO (if GIT_PROJECT_ROOT is set, otherwise PATH_TRANSLATED)
+* REMOTE_USER
+* REMOTE_ADDR
+* CONTENT_TYPE
+* QUERY_STRING
+* REQUEST_METHOD
+
+The `GIT_HTTP_EXPORT_ALL` environmental variable may be passed to
+'git-http-backend' to bypass the check for the "git-daemon-export-ok"
+file in each repository before allowing export of that repository.
+
+The `GIT_HTTP_MAX_REQUEST_BUFFER` environment variable (or the
+`http.maxRequestBuffer` config variable) may be set to change the
+largest ref negotiation request that git will handle during a fetch; any
+fetch requiring a larger buffer will not succeed.  This value should not
+normally need to be changed, but may be helpful if you are fetching from
+a repository with an extremely large number of refs.  The value can be
+specified with a unit (e.g., `100M` for 100 megabytes). The default is
+10 megabytes.
+
+The backend process sets GIT_COMMITTER_NAME to '$REMOTE_USER' and
+GIT_COMMITTER_EMAIL to '$\{REMOTE_USER}@http.$\{REMOTE_ADDR\}',
+ensuring that any reflogs created by 'git-receive-pack' contain some
+identifying information of the remote user who performed the push.
+
+All `CGI` environment variables are available to each of the hooks
+invoked by the 'git-receive-pack'.
+
+GIT
+---
+Part of the linkgit:git[1] suite