aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/tty/n_tty.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/tty/n_tty.c')
-rw-r--r--drivers/tty/n_tty.c92
1 files changed, 73 insertions, 19 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 640c9e871044..3afdd9033a9c 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -118,6 +118,9 @@ struct n_tty_data {
size_t read_tail;
size_t line_start;
+ /* # of chars looked ahead (to find software flow control chars) */
+ size_t lookahead_count;
+
/* protected by output lock */
unsigned int column;
unsigned int canon_column;
@@ -333,6 +336,8 @@ 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;
+
+ ldata->lookahead_count = 0;
}
static void n_tty_packet_mode_flush(struct tty_struct *tty)
@@ -1225,12 +1230,30 @@ static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
return c == START_CHAR(tty) || c == STOP_CHAR(tty);
}
-/* Returns true if c is consumed as flow-control character */
-static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
+/**
+ * n_tty_receive_char_flow_ctrl - receive flow control chars
+ * @tty: terminal device
+ * @c: character
+ * @lookahead_done: lookahead has processed this character already
+ *
+ * Receive and process flow control character actions.
+ *
+ * In case lookahead for flow control chars already handled the character in
+ * advance to the normal receive, the actions are skipped during normal
+ * receive.
+ *
+ * Returns true if @c is consumed as flow-control character, the character
+ * must not be treated as normal character.
+ */
+static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c,
+ bool lookahead_done)
{
if (!n_tty_is_char_flow_ctrl(tty, c))
return false;
+ if (lookahead_done)
+ return true;
+
if (c == START_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
@@ -1242,11 +1265,12 @@ static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c
return true;
}
-static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
+static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c,
+ bool lookahead_done)
{
struct n_tty_data *ldata = tty->disc_data;
- if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c))
+ if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c, lookahead_done))
return;
if (L_ISIG(tty)) {
@@ -1401,7 +1425,8 @@ static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
put_tty_queue(c, ldata);
}
-static 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,
+ bool lookahead_done)
{
if (I_ISTRIP(tty))
c &= 0x7f;
@@ -1409,12 +1434,10 @@ static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
c = tolower(c);
if (I_IXON(tty)) {
- if (c == STOP_CHAR(tty))
- stop_tty(tty);
- else if (c == START_CHAR(tty) ||
- (tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) &&
- c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
- c != SUSP_CHAR(tty))) {
+ if (!n_tty_receive_char_flow_ctrl(tty, c, lookahead_done) &&
+ tty->flow.stopped && !tty->flow.tco_stopped && I_IXANY(tty) &&
+ c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
+ c != SUSP_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
}
@@ -1457,6 +1480,27 @@ n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
n_tty_receive_char_flagged(tty, c, flag);
}
+/* Caller must ensure count > 0 */
+static void n_tty_lookahead_flow_ctrl(struct tty_struct *tty, const unsigned char *cp,
+ const unsigned char *fp, unsigned int count)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ unsigned char flag = TTY_NORMAL;
+
+ ldata->lookahead_count += count;
+
+ if (!I_IXON(tty))
+ return;
+
+ while (count--) {
+ if (fp)
+ flag = *fp++;
+ if (likely(flag == TTY_NORMAL))
+ n_tty_receive_char_flow_ctrl(tty, *cp, false);
+ cp++;
+ }
+}
+
static void
n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
const char *fp, int count)
@@ -1496,7 +1540,7 @@ n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
static void
n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
- const char *fp, int count)
+ const char *fp, int count, bool lookahead_done)
{
char flag = TTY_NORMAL;
@@ -1504,12 +1548,12 @@ n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
if (fp)
flag = *fp++;
if (likely(flag == TTY_NORMAL))
- n_tty_receive_char_closing(tty, *cp++);
+ n_tty_receive_char_closing(tty, *cp++, lookahead_done);
}
}
static void n_tty_receive_buf_standard(struct tty_struct *tty,
- const unsigned char *cp, const char *fp, int count)
+ const unsigned char *cp, const char *fp, int count, bool lookahead_done)
{
struct n_tty_data *ldata = tty->disc_data;
char flag = TTY_NORMAL;
@@ -1540,7 +1584,7 @@ static void n_tty_receive_buf_standard(struct tty_struct *tty,
}
if (test_bit(c, ldata->char_map))
- n_tty_receive_char_special(tty, c);
+ n_tty_receive_char_special(tty, c, lookahead_done);
else
n_tty_receive_char(tty, c);
}
@@ -1551,21 +1595,30 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
{
struct n_tty_data *ldata = tty->disc_data;
bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
+ size_t la_count = min_t(size_t, ldata->lookahead_count, count);
if (ldata->real_raw)
n_tty_receive_buf_real_raw(tty, cp, fp, count);
else if (ldata->raw || (L_EXTPROC(tty) && !preops))
n_tty_receive_buf_raw(tty, cp, fp, count);
- else if (tty->closing && !L_EXTPROC(tty))
- n_tty_receive_buf_closing(tty, cp, fp, count);
- else {
- n_tty_receive_buf_standard(tty, cp, fp, count);
+ else if (tty->closing && !L_EXTPROC(tty)) {
+ if (la_count > 0)
+ n_tty_receive_buf_closing(tty, cp, fp, la_count, true);
+ if (count > la_count)
+ n_tty_receive_buf_closing(tty, cp, fp, count - la_count, false);
+ } else {
+ if (la_count > 0)
+ n_tty_receive_buf_standard(tty, cp, fp, la_count, true);
+ if (count > la_count)
+ n_tty_receive_buf_standard(tty, cp, fp, count - la_count, false);
flush_echoes(tty);
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
}
+ ldata->lookahead_count -= la_count;
+
if (ldata->icanon && !L_EXTPROC(tty))
return;
@@ -2446,6 +2499,7 @@ static struct tty_ldisc_ops n_tty_ops = {
.receive_buf = n_tty_receive_buf,
.write_wakeup = n_tty_write_wakeup,
.receive_buf2 = n_tty_receive_buf2,
+ .lookahead_buf = n_tty_lookahead_flow_ctrl,
};
/**
generated by cgit (git 2.34.1) at 2025-02-27 03:29:48 +0000