static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
const unsigned char *p;
char *f, flags = TTY_NORMAL;
int i;
char buf[64];
unsigned long cpuflags;
if (!tty->read_buf)//在TTY OPEN时调用n_tty_open分配
return;
if (tty->real_raw) {//不是real_raw
spin_lock_irqsave(&tty->read_lock, cpuflags);
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
N_TTY_BUF_SIZE - tty->read_head);
i = min(count, i);
memcpy(tty->read_buf + tty->read_head, cp, i);
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
tty->read_cnt += i;
cp += i;
count -= i;
i = min(N_TTY_BUF_SIZE - tty->read_cnt,
N_TTY_BUF_SIZE - tty->read_head);
i = min(count, i);
memcpy(tty->read_buf + tty->read_head, cp, i);
tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1);
tty->read_cnt += i;
spin_unlock_irqrestore(&tty->read_lock, cpuflags);
} else {
for (i = count, p = cp, f = fp; i; i--, p++) {
if (f)
flags = *f++;
switch (flags) {//当输入'l'时flags为TTY_NORMAL
case TTY_NORMAL:
n_tty_receive_char(tty, *p);
break;
case TTY_BREAK:
n_tty_receive_break(tty);
break;
case TTY_PARITY:
case TTY_FRAME:
n_tty_receive_parity_error(tty, *p);
break;
case TTY_OVERRUN:
n_tty_receive_overrun(tty);
break;
default:
printk(KERN_ERR "%s: unknown flag %d\n",
tty_name(tty, buf), flags);
break;
}
}
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
}
n_tty_set_room(tty);
if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
}
/*
* Check the remaining room for the input canonicalization
* mode. We don't want to throttle the driver if we're in
* canonical mode and don't have a newline yet!
*/
if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
tty_throttle(tty);
}
static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
{
unsigned long flags;
int parmrk;
if (tty->raw) {//false
put_tty_queue(c, tty);
return;
}
if (I_ISTRIP(tty))//false
c &= 0x7f;
if (I_IUCLC(tty) && L_IEXTEN(tty))//I_IUCLC(tty)为false
c = tolower(c);
if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
}
if (tty->closing) {
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
} else if (c == STOP_CHAR(tty))
stop_tty(tty);
}
return;
}
/*
* If the previous character was LNEXT, or we know that this
* character is not one of the characters that we'll have to
* handle specially, do shortcut processing to speed things
* up.
*/
if (!test_bit(c, tty->process_char_map) || tty->lnext) {//输入'l'
tty->lnext = 0;
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
/* beep if no space */
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty)) {//字符回显处理
finish_erasing(tty);
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
echo_set_canon_col(tty);
echo_char(c, tty);//字符方式回显buf
process_echoes(tty);//处理回显
}
if (parmrk)
put_tty_queue(c, tty);
put_tty_queue(c, tty);
return;
}
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
return;
}
if (c == STOP_CHAR(tty)) {
stop_tty(tty);
return;
}
}
if (L_ISIG(tty)) {
int signal;
signal = SIGINT;
if (c == INTR_CHAR(tty))
goto send_signal;
signal = SIGQUIT;
if (c == QUIT_CHAR(tty))
goto send_signal;
signal = SIGTSTP;
if (c == SUSP_CHAR(tty)) {
send_signal:
/*
* Note that we do not use isig() here because we want
* the order to be:
* 1) flush, 2) echo, 3) signal
*/
if (!L_NOFLSH(tty)) {
n_tty_flush_buffer(tty);
tty_driver_flush_buffer(tty);
}
if (I_IXON(tty))
start_tty(tty);
if (L_ECHO(tty)) {
echo_char(c, tty);
process_echoes(tty);
}
if (tty->pgrp)
kill_pgrp(tty->pgrp, signal, 1);
return;
}
}
if (c == '\r') {
if (I_IGNCR(tty))
return;
if (I_ICRNL(tty))
c = '\n';
} else if (c == '\n' && I_INLCR(tty))
c = '\r';
if (tty->icanon) {
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
eraser(c, tty);
process_echoes(tty);
return;
}
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
tty->lnext = 1;
if (L_ECHO(tty)) {
finish_erasing(tty);
if (L_ECHOCTL(tty)) {
echo_char_raw('^', tty);
echo_char_raw('\b', tty);
process_echoes(tty);
}
}
return;
}
if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
L_IEXTEN(tty)) {
unsigned long tail = tty->canon_head;
finish_erasing(tty);
echo_char(c, tty);
echo_char_raw('\n', tty);
while (tail != tty->read_head) {
echo_char(tty->read_buf[tail], tty);
tail = (tail+1) & (N_TTY_BUF_SIZE-1);
}
process_echoes(tty);
return;
}
if (c == '\n') {
if (tty->read_cnt >= N_TTY_BUF_SIZE) {
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty) || L_ECHONL(tty)) {
echo_char_raw('\n', tty);
process_echoes(tty);
}
goto handle_newline;
}
if (c == EOF_CHAR(tty)) {
if (tty->read_cnt >= N_TTY_BUF_SIZE)
return;
if (tty->canon_head != tty->read_head)
set_bit(TTY_PUSH, &tty->flags);
c = __DISABLED_CHAR;
goto handle_newline;
}
if ((c == EOL_CHAR(tty)) ||
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
? 1 : 0;
if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
/*
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
*/
if (L_ECHO(tty)) {
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
echo_set_canon_col(tty);
echo_char(c, tty);
process_echoes(tty);
}
/*
* XXX does PARMRK doubling happen for
* EOL_CHAR and EOL2_CHAR?
*/
if (parmrk)
put_tty_queue(c, tty);
handle_newline:
spin_lock_irqsave(&tty->read_lock, flags);
set_bit(tty->read_head, tty->read_flags);
put_tty_queue_nolock(c, tty);
tty->canon_head = tty->read_head;
tty->canon_data++;
spin_unlock_irqrestore(&tty->read_lock, flags);
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
return;
}
}
parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
/* beep if no space */
if (L_ECHO(tty))
process_output('\a', tty);
return;
}
if (L_ECHO(tty)) {
finish_erasing(tty);
if (c == '\n')
echo_char_raw('\n', tty);
else {
/* Record the column of first canon char. */
if (tty->canon_head == tty->read_head)
echo_set_canon_col(tty);
echo_char(c, tty);
}
process_echoes(tty);
}
if (parmrk)
put_tty_queue(c, tty);
put_tty_queue(c, tty);
}
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