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| author | Paul Fulghum <paulkf@microgate.com> | 2007-05-12 10:36:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-12 10:55:39 -0700 |
| commit | c5c34d4862e18ef07c1276d233507f540fb5a532 (patch) | |
| tree | a0645f236a8bd2492476d1e24fbf94d5cd7edc30 | |
| parent | e3bf460f3eb86cdbc76725a0dac1f191e796676c (diff) | |
| download | linux-c5c34d4862e18ef07c1276d233507f540fb5a532.tar.gz linux-c5c34d4862e18ef07c1276d233507f540fb5a532.tar.bz2 linux-c5c34d4862e18ef07c1276d233507f540fb5a532.zip | |
tty: flush flip buffer on ldisc input queue flush
Flush the tty flip buffer when the line discipline input queue is flushed,
including the user call tcflush(TCIFLUSH/TCIOFLUSH). This prevents
unexpected stale data after a user application calls tcflush().
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Antonino Ingargiola <tritemio@gmail.com>
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/char/tty_io.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index bc849957508d..75d2a46e106f 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -369,6 +369,29 @@ static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) } /** + * tty_buffer_flush - flush full tty buffers + * @tty: tty to flush + * + * flush all the buffers containing receive data + * + * Locking: none + */ + +static void tty_buffer_flush(struct tty_struct *tty) +{ + struct tty_buffer *thead; + unsigned long flags; + + spin_lock_irqsave(&tty->buf.lock, flags); + while((thead = tty->buf.head) != NULL) { + tty->buf.head = thead->next; + tty_buffer_free(tty, thead); + } + tty->buf.tail = NULL; + spin_unlock_irqrestore(&tty->buf.lock, flags); +} + +/** * tty_buffer_find - find a free tty buffer * @tty: tty owning the buffer * @size: characters wanted @@ -1248,6 +1271,7 @@ void tty_ldisc_flush(struct tty_struct *tty) ld->flush_buffer(tty); tty_ldisc_deref(ld); } + tty_buffer_flush(tty); } EXPORT_SYMBOL_GPL(tty_ldisc_flush); @@ -3350,6 +3374,15 @@ int tty_ioctl(struct inode * inode, struct file * file, case TIOCMBIC: case TIOCMBIS: return tty_tiocmset(tty, file, cmd, p); + case TCFLSH: + switch (arg) { + case TCIFLUSH: + case TCIOFLUSH: + /* flush tty buffer and allow ldisc to process ioctl */ + tty_buffer_flush(tty); + break; + } + break; } if (tty->driver->ioctl) { retval = (tty->driver->ioctl)(tty, file, cmd, arg); |