diff options
| -rw-r--r-- | drivers/tty/n_tty.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index fdc2ecd..961e6a9 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -104,6 +104,7 @@ struct n_tty_data { /* must hold exclusive termios_rwsem to reset these */ unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; + unsigned char push:1; /* shared by producer and consumer */ char read_buf[N_TTY_BUF_SIZE]; @@ -341,6 +342,7 @@ static void reset_buffer_flags(struct n_tty_data *ldata) ldata->erasing = 0; bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); + ldata->push = 0; } static void n_tty_packet_mode_flush(struct tty_struct *tty) @@ -1745,7 +1747,16 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) { bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); - ldata->line_start = ldata->canon_head = ldata->read_tail; + ldata->line_start = ldata->read_tail; + if (!L_ICANON(tty) || !read_cnt(ldata)) { + ldata->canon_head = ldata->read_tail; + ldata->push = 0; + } else { + set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1), + ldata->read_flags); + ldata->canon_head = ldata->read_head; + ldata->push = 1; + } ldata->erasing = 0; ldata->lnext = 0; } @@ -1951,6 +1962,12 @@ static int copy_from_read_buf(struct tty_struct *tty, * it copies one line of input up to and including the line-delimiting * character into the user-space buffer. * + * NB: When termios is changed from non-canonical to canonical mode and + * the read buffer contains data, n_tty_set_termios() simulates an EOF + * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer. + * This causes data already processed as input to be immediately available + * as input although a newline has not been received. + * * Called under the atomic_read_lock mutex * * n_tty_read()/consumer path: @@ -1997,7 +2014,7 @@ static int canon_copy_from_read_buf(struct tty_struct *tty, n += found; c = n; - if (found && read_buf(ldata, eol) == __DISABLED_CHAR) { + if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) { n--; eof_push = !n && ldata->read_tail != ldata->line_start; } @@ -2024,7 +2041,10 @@ static int canon_copy_from_read_buf(struct tty_struct *tty, ldata->read_tail += c; if (found) { - ldata->line_start = ldata->read_tail; + if (!ldata->push) + ldata->line_start = ldata->read_tail; + else + ldata->push = 0; tty_audit_push(tty); } return eof_push ? -EAGAIN : 0; |