Push from an SSH Terminal

Hi Everyone,

I tried looking for an answer to my problem online without much luck,
perhaps you can help me.  I'm SSHed from my laptop(Comp A) over to a
computer(Comp B) that has my git repo on it. I made some changes and
comitted them. Now I want to push them to my other server(Comp C). The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

--
Feanil Patel

The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

What protocol are you using to access the repository on Comp C?

- Neal

On Fri, Feb 3, 2012 at 11:21 AM, Neal Groothuis [off-list ref] wrote:

quoted

The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

What protocol are you using to access the repository on Comp C?

- Neal

I'm pulling and pushing over HTTP from Comp C.

On Fri, Feb 3, 2012 at 11:21 AM, Neal Groothuis [off-list ref] wrote:

quoted

quoted

The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

What protocol are you using to access the repository on Comp C?

I'm pulling and pushing over HTTP from Comp C.

Check to see if the GIT_ASKPASS and/or SSH_ASKPASS environment variables
are set, and if the core.askpass config variable is set.  If any of these
are set, unset them.  Git should fall back to a simple password prompt.

- Neal

On Fri, Feb 03, 2012 at 10:50:02AM -0500, Feanil Patel wrote:

I tried looking for an answer to my problem online without much luck,
perhaps you can help me.  I'm SSHed from my laptop(Comp A) over to a
computer(Comp B) that has my git repo on it. I made some changes and
comitted them. Now I want to push them to my other server(Comp C). The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

Git should prompt you on the terminal (i.e., the ssh session) if it
needs credentials. If it is not, and the terminal is accessible, it
might be a bug. There were some fixes around this area that went into
1.7.9; you might try using that version.

Also, 1.7.9 ships with support for credential helper scripts, which can
help you avoid putting in your password less frequently (see "git help
credentials" in git 1.7.9).

-Peff

On Fri, Feb 03, 2012 at 12:10:27PM -0500, Neal Groothuis wrote:

quoted

On Fri, Feb 3, 2012 at 11:21 AM, Neal Groothuis [off-list ref] wrote:

quoted

quoted

The
repository is password protected so if I'm physically at Comp B, I get
a gui prompt for my username and password. However Comp A does not
have X Forwarding setup to Comp B so I can't get the gui interface for
the username and password when I try to do the push.  Is there an
alternative way to provide my credentials when doing a git push that
does not require a gui?

What protocol are you using to access the repository on Comp C?

I'm pulling and pushing over HTTP from Comp C.

Check to see if the GIT_ASKPASS and/or SSH_ASKPASS environment variables
are set, and if the core.askpass config variable is set.  If any of these
are set, unset them.  Git should fall back to a simple password prompt.

Hmm, yeah that is likely the problem. I was thinking git would fall back
to asking on the terminal, but it does not. We probably should.

-Peff

On Fri, Feb 03, 2012 at 04:36:54PM -0500, Jeff King wrote:

quoted

Check to see if the GIT_ASKPASS and/or SSH_ASKPASS environment variables
are set, and if the core.askpass config variable is set.  If any of these
are set, unset them.  Git should fall back to a simple password prompt.

Hmm, yeah that is likely the problem. I was thinking git would fall back
to asking on the terminal, but it does not. We probably should.

We should probably do this:

  [1/2]: prompt: clean up strbuf usage
  [2/2]: prompt: fall back to terminal if askpass fails

-Peff

The do_askpass function inherited a few bad habits from the
original git_getpass. One, there's no need to strbuf_reset a
buffer which was just initialized. And two, it's a good
habit to use strbuf_detach to claim ownership of a buffer's
string (even though in this case the owning buffer goes out
of scope, so it's effectively the same thing).

Signed-off-by: Jeff King <redacted>
---
Neither is a big deal, but just some style cleanups while I was in the
area.

 prompt.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/prompt.c b/prompt.c
index 72ab9de..64f817b 100644
--- a/prompt.c
+++ b/prompt.c

@@ -21,7 +21,6 @@ static char *do_askpass(const char *cmd, const char *prompt)
 	if (start_command(&pass))
 		exit(1);
 
-	strbuf_reset(&buffer);
 	if (strbuf_read(&buffer, pass.out, 20) < 0)
 		die("failed to get '%s' from %s\n", prompt, cmd);
 

@@ -32,7 +31,7 @@ static char *do_askpass(const char *cmd, const char *prompt)
 
 	strbuf_setlen(&buffer, strcspn(buffer.buf, "\r\n"));
 
-	return buffer.buf;
+	return strbuf_detach(&buffer, NULL);
 }
 
 char *git_prompt(const char *prompt, int flags)

-- 
1.7.9.rc1.28.gf4be5

The current askpass code simply dies if calling an askpass
helper fails. Worse, in some failure modes it doesn't even
print an error (if start_command fails, then it prints its
own error; if reading fails, we print an error; but if the
command exits non-zero, finish_command fails and we print
nothing!).

Let's be more kind to the user by printing an error message
when askpass doesn't work out, and then falling back to the
terminal (which also may fail, of course, but we die already
there with a nice message).

While we're at it, let's clean up the existing error
messages a bit.  Now that our prompts are very long and
contain quotes and colons themselves, our error messages are
hard to read.

So the new failure modes look like:

  [before, with a terminal]
  $ GIT_ASKPASS=false git push
  $ echo $?
  128

  [before, with no terminal, and we must give up]
  $ setsid git push
  fatal: could not read 'Password for 'https://peff@github.com': ': No such device or address

  [after, with a terminal]
  $ GIT_ASKPASS=false git push
  error: unable to read askpass response from 'false'
  Password for 'https://peff@github.com':

  [after, with no terminal, and we must give up]
  $ GIT_ASKPASS=false setsid git push
  error: unable to read askpass response from 'false'
  fatal: could not read Password for 'https://peff@github.com': No such device or address

Signed-off-by: Jeff King <redacted>
---
Arguably, the terminal-failure error message shouldn't even bother
reporting errno. I can't imagine it failing for any reason other than
ENODEV, and the message would probably be less confusing as:

  fatal: could not prompt on terminal for Password for...

 prompt.c |   24 +++++++++++++++++-------
 1 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/prompt.c b/prompt.c
index 64f817b..d851807 100644
--- a/prompt.c
+++ b/prompt.c

@@ -9,6 +9,7 @@ static char *do_askpass(const char *cmd, const char *prompt)
 	struct child_process pass;
 	const char *args[3];
 	static struct strbuf buffer = STRBUF_INIT;
+	int err = 0;
 
 	args[0] = cmd;
 	args[1]	= prompt;

@@ -19,15 +20,21 @@ static char *do_askpass(const char *cmd, const char *prompt)
 	pass.out = -1;
 
 	if (start_command(&pass))
-		exit(1);
+		return NULL;
 
 	if (strbuf_read(&buffer, pass.out, 20) < 0)
-		die("failed to get '%s' from %s\n", prompt, cmd);
+		err = 1;
 
 	close(pass.out);
 
 	if (finish_command(&pass))
-		exit(1);
+		err = 1;
+
+	if (err) {
+		error("unable to read askpass response from '%s'", cmd);
+		strbuf_release(&buffer);
+		return NULL;
+	}
 
 	strbuf_setlen(&buffer, strcspn(buffer.buf, "\r\n"));
 

@@ -36,7 +43,7 @@ static char *do_askpass(const char *cmd, const char *prompt)
 
 char *git_prompt(const char *prompt, int flags)
 {
-	char *r;
+	char *r = NULL;
 
 	if (flags & PROMPT_ASKPASS) {
 		const char *askpass;

@@ -47,12 +54,15 @@ char *git_prompt(const char *prompt, int flags)
 		if (!askpass)
 			askpass = getenv("SSH_ASKPASS");
 		if (askpass && *askpass)
-			return do_askpass(askpass, prompt);
+			r = do_askpass(askpass, prompt);
 	}
 
-	r = git_terminal_prompt(prompt, flags & PROMPT_ECHO);
 	if (!r)
-		die_errno("could not read '%s'", prompt);
+		r = git_terminal_prompt(prompt, flags & PROMPT_ECHO);
+	if (!r) {
+		/* prompts already contain ": " at the end */
+		die("could not read %s%s", prompt, strerror(errno));
+	}
 	return r;
 }
 

-- 
1.7.9.rc1.28.gf4be5