diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index efc72104c840..bdc314aeab88 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1975,6 +1975,35 @@ static bool canon_copy_from_read_buf(struct tty_struct *tty, return ldata->read_tail != canon_head; } +/* + * If we finished a read at the exact location of an + * EOF (special EOL character that's a __DISABLED_CHAR) + * in the stream, silently eat the EOF. + */ +static void canon_skip_eof(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + size_t tail, canon_head; + + canon_head = smp_load_acquire(&ldata->canon_head); + tail = ldata->read_tail; + + // No data? + if (tail == canon_head) + return; + + // See if the tail position is EOF in the circular buffer + tail &= (N_TTY_BUF_SIZE - 1); + if (!test_bit(tail, ldata->read_flags)) + return; + if (read_buf(ldata, tail) != __DISABLED_CHAR) + return; + + // Clear the EOL bit, skip the EOF char. + clear_bit(tail, ldata->read_flags); + smp_store_release(&ldata->read_tail, ldata->read_tail + 1); +} + /** * job_control - check job control * @tty: tty @@ -2045,7 +2074,14 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, */ if (*cookie) { if (ldata->icanon && !L_EXTPROC(tty)) { - if (canon_copy_from_read_buf(tty, &kb, &nr)) + /* + * If we have filled the user buffer, see + * if we should skip an EOF character before + * releasing the lock and returning done. + */ + if (!nr) + canon_skip_eof(tty); + else if (canon_copy_from_read_buf(tty, &kb, &nr)) return kb - kbuf; } else { if (copy_from_read_buf(tty, &kb, &nr)) |