Re: [PATCH] Avoid crippled getpass function on Solaris

[Jeff King <peff@peff.net>]

On Mon, Aug 06, 2012 at 08:23:18PM -0400, Jeff King wrote:

> This is all moot if we end up ripping stdio out of this code for other
> reasons, but it does give us another option for a fix.

And here is what that patch would look like:

-- >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 immediately followed by
reading) is also disallowed, but our fflush immediately
after printing the prompt is sufficient to satisfy the
standard.
---
 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);
 	}