git-daemon: set REMOTE_ADDR to client address

This allows hooks like pre-receive to look at the client's IP
address.

Of course the IP address can't be used to get strong security;
git-daemon isn't the right thing to use if you need that. However,
basic IP address checking can be good enough in some situations.

REMOTE_ADDR is the same environment variable used to communicate the
client's address to CGI scripts.
Signed-off-by: NJoey Hess <joey@kitenet.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-daemon.txt

@@ -270,6 +270,15 @@ selectively enable/disable services per repository::
 ----------------------------------------------------------------
 
 
+ENVIRONMENT
+-----------
+'git-daemon' will set REMOTE_ADDR to the IP address of the client
+that connected to it, if the IP address is available. REMOTE_ADDR will
+be available in the environment of hooks called when
+services are performed.
+
+
+
 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>, YOSHIFUJI Hideaki

daemon.c

@@ -537,6 +537,10 @@ static int execute(struct sockaddr *addr)
 #endif
 		}
 		loginfo("Connection from %s:%d", addrbuf, port);
+		setenv("REMOTE_ADDR", addrbuf, 1);
+	}
+	else {
+		unsetenv("REMOTE_ADDR");
 	}
 
 	alarm(init_timeout ? init_timeout : timeout);