Re: [PATCH] Enable HAVE_DEV_TTY for Solaris

From: Jeff King <peff@peff.net>
Date: Aug 7, 2012, 04:10 UTC
Message-ID: <20120807041026.GA21918@sigill.intra.peff.net>
In-Reply-To: <20120807040326.GA18682@sigill.intra.peff.net>

On Tue, Aug 07, 2012 at 12:03:26AM -0400, Jeff King wrote:

Show 8 quoted lines

> > So which direction do you guys want to go?  Use the "bidirectional
> > stdio with fseek()" for now, with the expectation that Tay's other
> > series will rewrite it to fd based one?
> 
> I think so. The stdio fix is short and obviously correct, and then Tay
> can either refactor or not as he sees fit for his topic (although if we
> do switch to just a terminal_can_prompt() interface and get rid of the
> term_t ugliness, then there is not even any need to do the rewrite).

And here it is again, this time with a signed-off-by (I fixed my script after our last discussion, but accidentally copied an old version to the Solaris VM I just installed. ;) ).

-- >8 --
Subject: [PATCH] terminal: seek when switching between reading and writing

When a stdio stream is opened in update mode (e.g., "w+"), the C standard forbids switching between reading or writing without an intervening positioning function. Many implementations are lenient about this, but Solaris libc will flush the recently-read contents to the output buffer. In this instance, that meant writing the non-echoed password that the user just typed to the terminal.

Fix it by inserting a no-op fseek between the read and write.

The opposite direction (writing followed by reading) is also disallowed, but our intervening fflush is an acceptable positioning function for that alternative.

Signed-off-by: Jeff King <peff@peff.net>
---
 compat/terminal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compat/terminal.c b/compat/terminal.c
index 6d16c8f..bbb038d 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -59,6 +59,7 @@ char *git_terminal_prompt(const char *prompt, int echo)
 
 	r = strbuf_getline(&buf, fh, '\n');
 	if (!echo) {
+		fseek(fh, SEEK_CUR, 0);
 		putc('\n', fh);
 		fflush(fh);
 	}