Re: [PATCH] Ensure that SSH runs in non-interactive mode

From

Junio C Hamano <gitster@pobox.com>

Date

Jul 20, 2008, 18:23 UTC

Message-ID

<7v63r0bejy.fsf@gitster.siamese.dyndns.org>

In-Reply-To

<alpine.DEB.1.00.0807201214060.3305@eeepc-johanness>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

>> Ah, right. Would it be OK to add the `-x' flag to ssh instead?
>
> I think this would be the correct way, together with "-T".
>
>> I imagine that that might make git less portable to SSH implementations 
>> other than OpenSSH, but I don't know if that is considered a problem.
>
> Well, this was to be expected, after what I wrote in response to 3. in
> http://thread.gmane.org/gmane.comp.version-control.git/76650/focus=2598
>
> Reality always catches up with you, and here again we see that plink and 
> other siblings of OpenSSH should be best handled with scripts, preferably 
> ones that strip out options they do not recognize.
>
> IOW something like
>
> -- snip --
> #!/bin/bash
>
> plinkopt=
> while test $# != 0
> do
> 	case "$1" in
> 	-p)
> 		plinkopt="$plinkopt -P $2"
> 		shift
> 	;;
> 	-*)
> 		# unrecognized; strip out
> 	;;
> 	*)
> 		break
> 	;;
> 	esac
> 	shift
> done
>
> exec plink $plinkopt "$@"
> -- snap --

 * Have that "-x", "-T" in the command line we generate for OpenSSH;

 * Allow users to specify OpenSSH substitute via a configuration and/or
   environment variable, and have them use your script; and

 * Have a built-in logic for selected and common "OpenSSH substitute",
   e.g. plink.

Here is to get it started...

 connect.c |   30 +++++++++++++++++++++++++++---
 1 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/connect.c b/connect.c
index 574f42f..c72dd9e 100644
--- a/connect.c
+++ b/connect.c
@@ -599,12 +599,36 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 	conn->argv = arg = xcalloc(6, sizeof(*arg));
 	if (protocol == PROTO_SSH) {
 		const char *ssh = getenv("GIT_SSH");
+		const char *ssh_basename;
 		if (!ssh) ssh = "ssh";
 
+		ssh_basename = strrchr(ssh, '/');
+		ssh_basename = ssh_basename ? (ssh_basename + 1) : ssh;
+
 		*arg++ = ssh;
-		if (port) {
-			*arg++ = "-p";
-			*arg++ = port;
+		/*
+		 * Make sure to enlarge conn->argv if you add more
+		 * paremeters here.
+		 *
+		 * We know how to invoke a few ssh implementations
+		 * ourselves.
+		 */
+		if (!strcmp(ssh_basename, "plink")) {
+			if (port) {
+				*arg++ = "-P";
+				*arg++ = port;
+			}
+		} else {
+			/*
+			 * This is for stock OpenSSH, but you can have
+			 * your custom wrapper script to parse this
+			 * and invoke other ssh implementations after
+			 * rearranging parameters as well.
+			 */
+			if (port) {
+				*arg++ = "-p";
+				*arg++ = port;
+			}
 		}
 		*arg++ = host;
 	}