terminal: seek when switching between reading and writing
authorJeff King <peff@peff.net>
Tue, 7 Aug 2012 04:10:26 +0000 (00:10 -0400)
committerJunio C Hamano <gitster@pobox.com>
Tue, 7 Aug 2012 05:11:47 +0000 (22:11 -0700)
commit67ba123fd1fcb9a7699ae85f05f1229513322c1c
tree3c70f17eac81f82183b0419e8343b144a62eb851
parent21aeafceda2382d26bfa73a98ba45a937d65d77a
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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
compat/terminal.c