n_tty.c

arm平台上的uclinux系统全部源代码

			return;
		}
	}
	
	finish_erasing(tty);
	if (L_ECHO(tty)) {
		if (tty->read_cnt >= N_TTY_BUF_SIZE-1) {
			put_char('\a', tty); /* beep if no space */
			return;
		}
		if (c == '\n')
			opost('\n', tty);
		else {
			/* Record the column of first canon char. */
			if (tty->canon_head == tty->read_head)
				tty->canon_column = tty->column;
			echo_char(c, tty);
		}
	}

	if (I_PARMRK(tty) && c == (unsigned char) '\377')
		put_tty_queue(c, tty);

	put_tty_queue(c, tty);
}	

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 = 0;
	int	i;

	if (!tty->read_buf)
		return;

	if (tty->real_raw) {
		i = MIN(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
				   N_TTY_BUF_SIZE - tty->read_head));
		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(count, MIN(N_TTY_BUF_SIZE - tty->read_cnt,
			       N_TTY_BUF_SIZE - tty->read_head));
		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;
	} else {
		for (i=count, p = cp, f = fp; i; i--, p++) {
			if (f)
				flags = *f++;
			switch (flags) {
			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("%s: unknown flag %d\n", tty_name(tty),
				       flags);
				break;
			}
		}
		if (tty->driver.flush_chars)
			tty->driver.flush_chars(tty);
	}

	if (!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) {
		if (tty->fasync)
			kill_fasync(tty->fasync, SIGIO);
		if (tty->read_wait)
			wake_up_interruptible(&tty->read_wait);
	}

	if ((tty->read_cnt >= TTY_THRESHOLD_THROTTLE) &&
	    tty->driver.throttle &&
	    !set_bit(TTY_THROTTLED, &tty->flags))
		tty->driver.throttle(tty);
}

static int n_tty_receive_room(struct tty_struct *tty)
{
	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;

	/*
	 * If we are doing input canonicalization, and there are no
	 * pending newlines, let characters through without limit, so
	 * that erase characters will be handled.  Other excess
	 * characters will be beeped.
	 */
	if (tty->icanon && !tty->canon_data)
		return N_TTY_BUF_SIZE;

	if (left > 0)
		return left;
	return 0;
}

int is_ignored(int sig)
{
	return ((current->blocked & (1<<(sig-1))) ||
	        (current->sig->action[sig-1].sa_handler == SIG_IGN));
}

static void n_tty_set_termios(struct tty_struct *tty, struct termios * old)
{
	if (!tty)
		return;
	
	tty->icanon = (L_ICANON(tty) != 0);
	if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
	    I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
	    I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
	    I_PARMRK(tty)) {
		cli();
		memset(tty->process_char_map, 0, 256/8);

		if (I_IGNCR(tty) || I_ICRNL(tty))
			set_bit('\r', &tty->process_char_map);
		if (I_INLCR(tty))
			set_bit('\n', &tty->process_char_map);

		if (L_ICANON(tty)) {
			set_bit(ERASE_CHAR(tty), &tty->process_char_map);
			set_bit(KILL_CHAR(tty), &tty->process_char_map);
			set_bit(EOF_CHAR(tty), &tty->process_char_map);
			set_bit('\n', &tty->process_char_map);
			set_bit(EOL_CHAR(tty), &tty->process_char_map);
			if (L_IEXTEN(tty)) {
				set_bit(WERASE_CHAR(tty),
					&tty->process_char_map);
				set_bit(LNEXT_CHAR(tty),
					&tty->process_char_map);
				set_bit(EOL2_CHAR(tty),
					&tty->process_char_map);
				if (L_ECHO(tty))
					set_bit(REPRINT_CHAR(tty),
						&tty->process_char_map);
			}
		}
		if (I_IXON(tty)) {
			set_bit(START_CHAR(tty), &tty->process_char_map);
			set_bit(STOP_CHAR(tty), &tty->process_char_map);
		}
		if (L_ISIG(tty)) {
			set_bit(INTR_CHAR(tty), &tty->process_char_map);
			set_bit(QUIT_CHAR(tty), &tty->process_char_map);
			set_bit(SUSP_CHAR(tty), &tty->process_char_map);
		}
		clear_bit(__DISABLED_CHAR, &tty->process_char_map);
		sti();
		tty->raw = 0;
		tty->real_raw = 0;
	} else {
		tty->raw = 1;
		if ((I_IGNBRK(tty) || (!I_BRKINT(tty) && !I_PARMRK(tty))) &&
		    (I_IGNPAR(tty) || !I_INPCK(tty)) &&
		    (tty->driver.flags & TTY_DRIVER_REAL_RAW))
			tty->real_raw = 1;
		else
			tty->real_raw = 0;
	}
}

static void n_tty_close(struct tty_struct *tty)
{
	n_tty_flush_buffer(tty);
	if (tty->read_buf) {
		kfree_s (tty->read_buf, N_TTY_BUF_SIZE);
		tty->read_buf = 0;
	}
}

static int n_tty_open(struct tty_struct *tty)
{
	if (!tty)
		return -EINVAL;

	if (!tty->read_buf) {
		tty->read_buf = (unsigned char *)
			kmalloc (N_TTY_BUF_SIZE, intr_count ? GFP_ATOMIC : GFP_KERNEL);
		if (!tty->read_buf)
			return -ENOMEM;
	}
	memset(tty->read_buf, 0, N_TTY_BUF_SIZE);
	tty->read_head = tty->read_tail = tty->read_cnt = 0;
	tty->canon_head = tty->canon_data = tty->erasing = 0;
	tty->column = 0;
	memset(tty->read_flags, 0, sizeof(tty->read_flags));
	n_tty_set_termios(tty, 0);
	tty->minimum_to_wake = 1;
	tty->closing = 0;
	return 0;
}

static inline int input_available_p(struct tty_struct *tty, int amt)
{
	if (L_ICANON(tty)) {
		if (tty->canon_data)
			return 1;
	} else if (tty->read_cnt >= (amt ? amt : 1))
		return 1;

	return 0;
}

/*
 * Helper function to speed up read_chan.  It is only called when
 * ICANON is off; it copies characters straight from the tty queue to
 * user space directly.  It can be profitably called twice; once to
 * drain the space from the tail pointer to the (physical) end of the
 * buffer, and once to drain the space from the (physical) beginning of
 * the buffer to head pointer.
 */
static inline void copy_from_read_buf(struct tty_struct *tty,
				      unsigned char **b,
				      unsigned int *nr)

{
	int	n;

	n = MIN(*nr, MIN(tty->read_cnt, N_TTY_BUF_SIZE - tty->read_tail));
	if (!n)
		return;
	memcpy_tofs(*b, &tty->read_buf[tty->read_tail], n);
	tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
	tty->read_cnt -= n;
	*b += n;
	*nr -= n;
}

static int read_chan(struct tty_struct *tty, struct file *file,
		     unsigned char *buf, unsigned int nr)
{
	struct wait_queue wait = { current, NULL };
	int c;
	unsigned char *b = buf;
	int minimum, time;
	int retval = 0;
	int size;

do_it_again:

	if (!tty->read_buf) {
		printk("n_tty_read_chan: called with read_buf == NULL?!?\n");
		return -EIO;
	}

	/* Job control check -- must be done at start and after
	   every sleep (POSIX.1 7.1.1.4). */
	/* NOTE: not yet done after every sleep pending a thorough
	   check of the logic of this change. -- jlc */
	/* don't stop on /dev/console */
	if (file->f_inode->i_rdev != CONSOLE_DEV &&
	    current->tty == tty) {
		if (tty->pgrp <= 0)
			printk("read_chan: tty->pgrp <= 0!\n");
		else if (current->pgrp != tty->pgrp) {
			if (is_ignored(SIGTTIN) ||
			    is_orphaned_pgrp(current->pgrp))
				return -EIO;
			kill_pg(current->pgrp, SIGTTIN, 1);
			return -ERESTARTSYS;
		}
	}

	if (L_ICANON(tty)) {
		minimum = time = 0;
		current->timeout = (unsigned long) -1;
	} else {
		time = (HZ / 10) * TIME_CHAR(tty);
		minimum = MIN_CHAR(tty);
		if (minimum) {
		  	current->timeout = (unsigned long) -1;
			if (time)
				tty->minimum_to_wake = 1;
			else if (!waitqueue_active(&tty->read_wait) ||
				 (tty->minimum_to_wake > minimum))
				tty->minimum_to_wake = minimum;
		} else {
			if (time) {
				current->timeout = time + jiffies;
				time = 0;
			} else
				current->timeout = 0;
			tty->minimum_to_wake = minimum = 1;
		}
	}

	add_wait_queue(&tty->read_wait, &wait);
	while (1) {
		/* First test for status change. */
		if (tty->packet && tty->link->ctrl_status) {
			if (b != buf)
				break;
			put_user(tty->link->ctrl_status, b++);
			tty->link->ctrl_status = 0;
			break;
		}
		/* This statement must be first before checking for input
		   so that any interrupt will set the state back to
		   TASK_RUNNING. */
		current->state = TASK_INTERRUPTIBLE;
		
		if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
		    ((minimum - (b - buf)) >= 1))
			tty->minimum_to_wake = (minimum - (b - buf));
		
		if (!input_available_p(tty, 0)) {
			if (tty->flags & (1 << TTY_OTHER_CLOSED)) {
				retval = -EIO;
				break;
			}
			if (tty_hung_up_p(file))
				break;
			if (!current->timeout)
				break;
			if (file->f_flags & O_NONBLOCK) {
				retval = -EAGAIN;
				break;
			}
			if (current->signal & ~current->blocked) {
				retval = -ERESTARTSYS;
				break;
			}
			schedule();
			continue;
		}
		current->state = TASK_RUNNING;

		/* Deal with packet mode. */
		if (tty->packet && b == buf) {
			put_user(TIOCPKT_DATA, b++);
			nr--;
		}

		if (L_ICANON(tty)) {
			while (1) {
				int eol;

				disable_bh(TQUEUE_BH);
				if (!tty->read_cnt) {
					enable_bh(TQUEUE_BH);
					break;
				}
				eol = clear_bit(tty->read_tail,
						&tty->read_flags);
				c = tty->read_buf[tty->read_tail];
				tty->read_tail = ((tty->read_tail+1) &
						  (N_TTY_BUF_SIZE-1));
				tty->read_cnt--;
				enable_bh(TQUEUE_BH);
				if (!eol) {
					put_user(c, b++);
					if (--nr)
						continue;
					break;
				}
				if (--tty->canon_data < 0) {
					tty->canon_data = 0;
				}
				if (c != __DISABLED_CHAR) {
					put_user(c, b++);
					nr--;
				}
				break;
			}
		} else {
			disable_bh(TQUEUE_BH);
			copy_from_read_buf(tty, &b, &nr);
			copy_from_read_buf(tty, &b, &nr);
			enable_bh(TQUEUE_BH);
		}

		/* If there is enough space in the read buffer now, let the
		   low-level driver know. */
		if (tty->driver.unthrottle &&
		    (tty->read_cnt <= TTY_THRESHOLD_UNTHROTTLE)
		    && clear_bit(TTY_THROTTLED, &tty->flags))
			tty->driver.unthrottle(tty);

		if (b - buf >= minimum || !nr)
			break;
		if (time)
			current->timeout = time + jiffies;
	}
	remove_wait_queue(&tty->read_wait, &wait);

	if (!waitqueue_active(&tty->read_wait))
		tty->minimum_to_wake = minimum;

	current->state = TASK_RUNNING;
	current->timeout = 0;
	size = b - buf;
	if (size && nr)
	        clear_bit(TTY_PUSH, &tty->flags);
        if (!size && clear_bit(TTY_PUSH, &tty->flags))
                goto do_it_again;
	if (!size && !retval)
	        clear_bit(TTY_PUSH, &tty->flags);
        return (size ? size : retval);
}

static int write_chan(struct tty_struct * tty, struct file * file,
		      const unsigned char * buf, unsigned int nr)
{
	struct wait_queue wait = { current, NULL };
	int c;
	const unsigned char *b = buf;
	int retval = 0;

	/* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
	if (L_TOSTOP(tty) && file->f_inode->i_rdev != CONSOLE_DEV) {
		retval = tty_check_change(tty);
		if (retval)
			return retval;
	}

	add_wait_queue(&tty->write_wait, &wait);
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		if (current->signal & ~current->blocked) {
			retval = -ERESTARTSYS;
			break;
		}
		if (tty_hung_up_p(file) || (tty->link && !tty->link->count)) {
			retval = -EIO;
			break;
		}
		if (O_OPOST(tty)) {
			while (nr > 0) {
				c = get_user(b);
				if (opost(c, tty) < 0)
					break;
				b++; nr--;
			}
			if (tty->driver.flush_chars)
				tty->driver.flush_chars(tty);
		} else {
			c = tty->driver.write(tty, 1, b, nr);
			b += c;
			nr -= c;
		}
		if (!nr)
			break;
		if (file->f_flags & O_NONBLOCK) {
			retval = -EAGAIN;
			break;
		}
		schedule();
	}
	current->state = TASK_RUNNING;
	remove_wait_queue(&tty->write_wait, &wait);
	return (b - buf) ? b - buf : retval;
}

static int normal_select(struct tty_struct * tty, struct inode * inode,
			 struct file * file, int sel_type, select_table *wait)
{
	switch (sel_type) {
		case SEL_IN:
			if (input_available_p(tty, TIME_CHAR(tty) ? 0 :
					      MIN_CHAR(tty)))
				return 1;
			/* fall through */
		case SEL_EX:
			if (tty->packet && tty->link->ctrl_status)
				return 1;
			if (tty->flags & (1 << TTY_OTHER_CLOSED))
				return 1;
			if (tty_hung_up_p(file))
				return 1;
			if (!waitqueue_active(&tty->read_wait)) {
				if (MIN_CHAR(tty) && !TIME_CHAR(tty))
					tty->minimum_to_wake = MIN_CHAR(tty);
				else
					tty->minimum_to_wake = 1;
			}
			select_wait(&tty->read_wait, wait);
			return 0;
		case SEL_OUT:
			if (tty->driver.chars_in_buffer(tty) < WAKEUP_CHARS)
				return 1;
			select_wait(&tty->write_wait, wait);
			return 0;
	}
	return 0;
}

struct tty_ldisc tty_ldisc_N_TTY = {
	TTY_LDISC_MAGIC,	/* magic */
	0,			/* num */
	0,			/* flags */
	n_tty_open,		/* open */
	n_tty_close,		/* close */
	n_tty_flush_buffer,	/* flush_buffer */
	n_tty_chars_in_buffer,	/* chars_in_buffer */
	read_chan,		/* read */
	write_chan,		/* write */
	n_tty_ioctl,		/* ioctl */
	n_tty_set_termios,	/* set_termios */
	normal_select,		/* select */
	n_tty_receive_buf,	/* receive_buf */
	n_tty_receive_room,	/* receive_room */
	0			/* write_wakeup */
};