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Subject[PATCH 60/79] n_tty: move echoctl check and clean up logic
Date
From: Joe Peterson <joe@skyrush.com>

Check L_ECHOCTL before insertting a character in the echo buffer
(rather than as the buffer is processed), to be more consistent with
when all other L_ flags are checked. Also cleaned up the related logic.

Note that this and the previous patch ("n_tty: honor opost flag for echoes")
were verified together by the reporters of the bug that patch addresses
(http://bugs.linuxbase.org/show_bug.cgi?id=2692), and the test now passes.

Signed-off-by: Joe Peterson <joe@skyrush.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/char/n_tty.c | 46 ++++++++++++++++++----------------------------
1 files changed, 18 insertions(+), 28 deletions(-)

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index e6eeeb2..2e50f4d 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -576,33 +576,23 @@ static void process_echoes(struct tty_struct *tty)
break;

default:
- if (iscntrl(op)) {
- if (L_ECHOCTL(tty)) {
- /*
- * Ensure there is enough space
- * for the whole ctrl pair.
- */
- if (space < 2) {
- no_space_left = 1;
- break;
- }
- tty_put_char(tty, '^');
- tty_put_char(tty, op ^ 0100);
- tty->column += 2;
- space -= 2;
- } else {
- if (!space) {
- no_space_left = 1;
- break;
- }
- tty_put_char(tty, op);
- space--;
- }
- }
/*
- * If above falls through, this was an
- * undefined op.
+ * If the op is not a special byte code,
+ * it is a ctrl char tagged to be echoed
+ * as "^X" (where X is the letter
+ * representing the control char).
+ * Note that we must ensure there is
+ * enough space for the whole ctrl pair.
+ *
*/
+ if (space < 2) {
+ no_space_left = 1;
+ break;
+ }
+ tty_put_char(tty, '^');
+ tty_put_char(tty, op ^ 0100);
+ tty->column += 2;
+ space -= 2;
cp += 2;
nr -= 2;
}
@@ -809,8 +799,8 @@ static void echo_char_raw(unsigned char c, struct tty_struct *tty)
* Echo user input back onto the screen. This must be called only when
* L_ECHO(tty) is true. Called from the driver receive_buf path.
*
- * This variant tags control characters to be possibly echoed as
- * as "^X" (where X is the letter representing the control char).
+ * This variant tags control characters to be echoed as "^X"
+ * (where X is the letter representing the control char).
*
* Locking: echo_lock to protect the echo buffer
*/
@@ -823,7 +813,7 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
add_echo_byte(ECHO_OP_START, tty);
add_echo_byte(ECHO_OP_START, tty);
} else {
- if (iscntrl(c) && c != '\t')
+ if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t')
add_echo_byte(ECHO_OP_START, tty);
add_echo_byte(c, tty);
}
--
1.6.4.2


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