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path: root/drivers/tty/n_tty.c
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Diffstat (limited to 'drivers/tty/n_tty.c')
-rw-r--r--drivers/tty/n_tty.c113
1 files changed, 62 insertions, 51 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 34aacaaae14a..cb8017aa4434 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -105,6 +105,7 @@ 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];
@@ -275,7 +276,8 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
return;
n_tty_set_room(tty);
n_tty_write_wakeup(tty->link);
- wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
+ if (waitqueue_active(&tty->link->write_wait))
+ wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
return;
}
@@ -342,6 +344,7 @@ 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)
@@ -351,7 +354,8 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
spin_lock_irqsave(&tty->ctrl_lock, flags);
if (tty->link->packet) {
tty->ctrl_status |= TIOCPKT_FLUSHREAD;
- wake_up_interruptible(&tty->link->read_wait);
+ if (waitqueue_active(&tty->link->read_wait))
+ wake_up_interruptible(&tty->link->read_wait);
}
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
}
@@ -1162,7 +1166,8 @@ static void n_tty_receive_break(struct tty_struct *tty)
put_tty_queue('\0', ldata);
}
put_tty_queue('\0', ldata);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}
/**
@@ -1220,7 +1225,8 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
put_tty_queue('\0', ldata);
else
put_tty_queue(c, ldata);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}
static void
@@ -1264,7 +1270,6 @@ static int
n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
- int parmrk;
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
@@ -1349,8 +1354,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
}
if ((c == EOL_CHAR(tty)) ||
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
- ? 1 : 0;
/*
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
*/
@@ -1365,7 +1368,7 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
* XXX does PARMRK doubling happen for
* EOL_CHAR and EOL2_CHAR?
*/
- if (parmrk)
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
put_tty_queue(c, ldata);
handle_newline:
@@ -1379,7 +1382,6 @@ handle_newline:
}
}
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (L_ECHO(tty)) {
finish_erasing(ldata);
if (c == '\n')
@@ -1393,7 +1395,8 @@ handle_newline:
commit_echoes(tty);
}
- if (parmrk)
+ /* PARMRK doubling check */
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
put_tty_queue(c, ldata);
put_tty_queue(c, ldata);
@@ -1404,7 +1407,6 @@ static inline void
n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
- int parmrk;
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
start_tty(tty);
@@ -1418,13 +1420,13 @@ n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
echo_char(c, tty);
commit_echoes(tty);
}
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
- if (parmrk)
+ /* PARMRK doubling check */
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
put_tty_queue(c, ldata);
put_tty_queue(c, ldata);
}
-static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
+static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
{
n_tty_receive_char_inline(tty, c);
}
@@ -1449,8 +1451,7 @@ n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
put_tty_queue(c, ldata);
}
-static inline void
-n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
+static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
{
if (I_ISTRIP(tty))
c &= 0x7f;
@@ -1681,32 +1682,9 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
}
}
-static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
- char *fp, int count)
-{
- int room, n;
-
- down_read(&tty->termios_rwsem);
-
- while (1) {
- room = receive_room(tty);
- n = min(count, room);
- if (!n)
- break;
- __receive_buf(tty, cp, fp, n);
- cp += n;
- if (fp)
- fp += n;
- count -= n;
- }
-
- tty->receive_room = room;
- n_tty_check_throttle(tty);
- up_read(&tty->termios_rwsem);
-}
-
-static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
- char *fp, int count)
+static int
+n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count, int flow)
{
struct n_tty_data *ldata = tty->disc_data;
int room, n, rcvd = 0;
@@ -1717,7 +1695,7 @@ static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
room = receive_room(tty);
n = min(count, room);
if (!n) {
- if (!room)
+ if (flow && !room)
ldata->no_room = 1;
break;
}
@@ -1736,6 +1714,18 @@ static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
return rcvd;
}
+static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ n_tty_receive_buf_common(tty, cp, fp, count, 0);
+}
+
+static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ return n_tty_receive_buf_common(tty, cp, fp, count, 1);
+}
+
int is_ignored(int sig)
{
return (sigismember(&current->blocked, sig) ||
@@ -1762,7 +1752,16 @@ 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;
}
@@ -1825,8 +1824,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
start_tty(tty);
/* The termios change make the tty ready for I/O */
- wake_up_interruptible(&tty->write_wait);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->write_wait))
+ wake_up_interruptible(&tty->write_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}
/**
@@ -1892,14 +1893,15 @@ err:
return -ENOMEM;
}
-static inline int input_available_p(struct tty_struct *tty, int amt)
+static inline int input_available_p(struct tty_struct *tty, int poll)
{
struct n_tty_data *ldata = tty->disc_data;
+ int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
if (ldata->icanon && !L_EXTPROC(tty)) {
if (ldata->canon_head != ldata->read_tail)
return 1;
- } else if (read_cnt(ldata) >= (amt ? amt : 1))
+ } else if (read_cnt(ldata) >= amt)
return 1;
return 0;
@@ -1965,6 +1967,12 @@ 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:
@@ -2011,7 +2019,7 @@ 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;
}
@@ -2038,7 +2046,10 @@ 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;
@@ -2398,7 +2409,7 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
poll_wait(file, &tty->read_wait, wait);
poll_wait(file, &tty->write_wait, wait);
- if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
+ if (input_available_p(tty, 1))
mask |= POLLIN | POLLRDNORM;
if (tty->packet && tty->link->ctrl_status)
mask |= POLLPRI | POLLIN | POLLRDNORM;