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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.c83
1 files changed, 57 insertions, 26 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index c7f8f7bc142..f44f1ba762c 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -93,6 +93,7 @@ struct n_tty_data {
size_t canon_head;
size_t echo_head;
size_t echo_commit;
+ size_t echo_mark;
DECLARE_BITMAP(char_map, 256);
/* private to n_tty_receive_overrun (single-threaded) */
@@ -104,6 +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];
@@ -337,10 +339,12 @@ static void reset_buffer_flags(struct n_tty_data *ldata)
{
ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
+ ldata->echo_mark = 0;
ldata->line_start = 0;
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)
@@ -789,6 +793,7 @@ static void commit_echoes(struct tty_struct *tty)
size_t head;
head = ldata->echo_head;
+ ldata->echo_mark = head;
old = ldata->echo_commit - ldata->echo_tail;
/* Process committed echoes if the accumulated # of bytes
@@ -812,10 +817,11 @@ static void process_echoes(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
size_t echoed;
- if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail)
+ if (ldata->echo_mark == ldata->echo_tail)
return;
mutex_lock(&ldata->output_lock);
+ ldata->echo_commit = ldata->echo_mark;
echoed = __process_echoes(tty);
mutex_unlock(&ldata->output_lock);
@@ -823,11 +829,13 @@ static void process_echoes(struct tty_struct *tty)
tty->ops->flush_chars(tty);
}
+/* NB: echo_mark and echo_head should be equivalent here */
static void flush_echoes(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
- if (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_head)
+ if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
+ ldata->echo_commit == ldata->echo_head)
return;
mutex_lock(&ldata->output_lock);
@@ -1206,15 +1214,16 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
- if (I_IGNPAR(tty))
- return;
- if (I_PARMRK(tty)) {
- put_tty_queue('\377', ldata);
- put_tty_queue('\0', ldata);
- put_tty_queue(c, ldata);
- } else if (I_INPCK(tty))
- put_tty_queue('\0', ldata);
- else
+ if (I_INPCK(tty)) {
+ if (I_IGNPAR(tty))
+ return;
+ if (I_PARMRK(tty)) {
+ put_tty_queue('\377', ldata);
+ put_tty_queue('\0', ldata);
+ put_tty_queue(c, ldata);
+ } else
+ put_tty_queue('\0', ldata);
+ } else
put_tty_queue(c, ldata);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
@@ -1235,7 +1244,8 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
if (L_ECHO(tty)) {
echo_char(c, tty);
commit_echoes(tty);
- }
+ } else
+ process_echoes(tty);
isig(signal, tty);
return;
}
@@ -1265,7 +1275,7 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
- commit_echoes(tty);
+ process_echoes(tty);
return 0;
}
if (c == STOP_CHAR(tty)) {
@@ -1743,7 +1753,16 @@ 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;
}
@@ -1802,8 +1821,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
* Fix tty hang when I_IXON(tty) is cleared, but the tty
* been stopped by STOP_CHAR(tty) before it.
*/
- if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped)
+ if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
start_tty(tty);
+ process_echoes(tty);
+ }
/* The termios change make the tty ready for I/O */
if (waitqueue_active(&tty->write_wait))
@@ -1878,15 +1899,12 @@ err:
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;
+ int amt = poll && !TIME_CHAR(tty) && MIN_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)
- return 1;
-
- return 0;
+ if (ldata->icanon && !L_EXTPROC(tty))
+ return ldata->canon_head != ldata->read_tail;
+ else
+ return read_cnt(ldata) >= amt;
}
/**
@@ -1949,6 +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:
@@ -1995,7 +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;
}
@@ -2018,11 +2042,14 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
if (found)
clear_bit(eol, ldata->read_flags);
- smp_mb__after_clear_bit();
+ smp_mb__after_atomic();
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;
@@ -2327,8 +2354,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
} else {
+ struct n_tty_data *ldata = tty->disc_data;
+
while (nr > 0) {
+ mutex_lock(&ldata->output_lock);
c = tty->ops->write(tty, b, nr);
+ mutex_unlock(&ldata->output_lock);
if (c < 0) {
retval = c;
goto break_out;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-09 13:11:37 +0000