n_tty: honor opost flag for echoes

Fixes the following bug:

      http://bugs.linuxbase.org/show_bug.cgi?id=2692

Causes processing of echoed characters (output from the echo buffer) to
honor the O_OPOST flag, which is consistent with the old behavior.

Note that this and the next patch ("n_tty: move echoctl check and
clean up logic") were verified together by the bug reporters, and
the test now passes.

Signed-off-by: Joe Peterson <joe@skyrush.com>
Cc: Linux Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 22 insertions, 11 deletions

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index 4e28b35024ec..e6eeeb234e5d 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -272,7 +272,8 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
  *
  *      This is a helper function that handles one output character
  *      (including special characters like TAB, CR, LF, etc.),
- *      putting the results in the tty driver's write buffer.
+ *      doing OPOST processing and putting the results in the
+ *      tty driver's write buffer.
  *
  *      Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
  *      and NLDLY.  They simply aren't relevant in the world today.
@@ -350,8 +351,9 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
  *      @c: character (or partial unicode symbol)
  *      @tty: terminal device
  *
- *      Perform OPOST processing.  Returns -1 when the output device is
- *      full and the character must be retried.
+ *      Output one character with OPOST processing.
+ *      Returns -1 when the output device is full and the character
+ *      must be retried.
  *
  *      Locking: output_lock to protect column state and space left
  *               (also, this is called from n_tty_write under the
@@ -377,8 +379,11 @@ static int process_output(unsigned char c, struct tty_struct *tty)
 /**
  *      process_output_block            -       block post processor
  *      @tty: terminal device
- *      @inbuf: user buffer
- *      @nr: number of bytes
+ *      @buf: character buffer
+ *      @nr: number of bytes to output
+ *
+ *      Output a block of characters with OPOST processing.
+ *      Returns the number of characters output.
  *
  *      This path is used to speed up block console writes, among other
  *      things when processing blocks of output data. It handles only
@@ -605,12 +610,18 @@ static void process_echoes(struct tty_struct *tty)
                         if (no_space_left)
                                 break;
                 } else {
-                        int retval;
-
-                        retval = do_output_char(c, tty, space);
-                        if (retval < 0)
-                                break;
-                        space -= retval;
+                        if (O_OPOST(tty) &&
+                            !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+                                int retval = do_output_char(c, tty, space);
+                                if (retval < 0)
+                                        break;
+                                space -= retval;
+                        } else {
+                                if (!space)
+                                        break;
+                                tty_put_char(tty, c);
+                                space -= 1;
+                        }
                         cp += 1;
                         nr -= 1;
                 }