tty_ioctl.c

LINUX1.0内核源代码,学习LINUX编程的一定要看。

int tty_ioctl(struct inode * inode, struct file * file,
	unsigned int cmd, unsigned long arg)
{
	struct tty_struct * tty;
	struct tty_struct * other_tty;
	struct tty_struct * termios_tty;
	pid_t pgrp;
	int dev;
	int termios_dev;
	int retval;

	if (MAJOR(file->f_rdev) != TTY_MAJOR) {
		printk("tty_ioctl: tty pseudo-major != TTY_MAJOR\n");
		return -EINVAL;
	}
	dev = MINOR(file->f_rdev);
	tty = TTY_TABLE(dev);
	if (!tty)
		return -EINVAL;
	if (IS_A_PTY(dev))
		other_tty = tty_table[PTY_OTHER(dev)];
	else
		other_tty = NULL;
	if (IS_A_PTY_MASTER(dev)) {
		termios_tty = other_tty;
		termios_dev = PTY_OTHER(dev);
	} else {
		termios_tty = tty;
		termios_dev = dev;
	}
	switch (cmd) {
		case TCGETS:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (struct termios));
			if (retval)
				return retval;
			memcpy_tofs((struct termios *) arg,
				    termios_tty->termios,
				    sizeof (struct termios));
			return 0;
		case TCSETSF:
		case TCSETSW:
		case TCSETS:
			retval = check_change(termios_tty, termios_dev);
			if (retval)
				return retval;
			if (cmd == TCSETSF || cmd == TCSETSW) {
				if (cmd == TCSETSF)
					flush_input(termios_tty);
				wait_until_sent(termios_tty, 0);
			}
			return set_termios(termios_tty, (struct termios *) arg,
					   termios_dev);
		case TCGETA:
			return get_termio(termios_tty,(struct termio *) arg);
		case TCSETAF:
		case TCSETAW:
		case TCSETA:
			retval = check_change(termios_tty, termios_dev);
			if (retval)
				return retval;
			if (cmd == TCSETAF || cmd == TCSETAW) {
				if (cmd == TCSETAF)
					flush_input(termios_tty);
				wait_until_sent(termios_tty, 0);
			}
			return set_termio(termios_tty, (struct termio *) arg,
					  termios_dev);
		case TCXONC:
			retval = check_change(tty, dev);
			if (retval)
				return retval;
			switch (arg) {
			case TCOOFF:
				stop_tty(tty);
				break;
			case TCOON:
				start_tty(tty);
				break;
			case TCIOFF:
				if (STOP_CHAR(tty) != __DISABLED_CHAR)
					put_tty_queue(STOP_CHAR(tty),
						      &tty->write_q);
				break;
			case TCION:
				if (START_CHAR(tty) != __DISABLED_CHAR)
					put_tty_queue(START_CHAR(tty),
						      &tty->write_q);
				break;
			default:
				return -EINVAL;
			}
			return 0;
		case TCFLSH:
			retval = check_change(tty, dev);
			if (retval)
				return retval;
			switch (arg) {
			case TCIFLUSH:
				flush_input(tty);
				break;
			case TCIOFLUSH:
				flush_input(tty);
				/* fall through */
			case TCOFLUSH:
				flush_output(tty);
				break;
			default:
				return -EINVAL;
			}
			return 0;
		case TIOCEXCL:
			set_bit(TTY_EXCLUSIVE, &tty->flags);
			return 0;
		case TIOCNXCL:
			clear_bit(TTY_EXCLUSIVE, &tty->flags);
			return 0;
		case TIOCSCTTY:
			if (current->leader &&
			    (current->session == tty->session))
				return 0;
			/*
			 * The process must be a session leader and
			 * not have a controlling tty already.
			 */
			if (!current->leader || (current->tty >= 0))
				return -EPERM;
			if (tty->session > 0) {
				/*
				 * This tty is already the controlling
				 * tty for another session group!
				 */
				if ((arg == 1) && suser()) {
					/*
					 * Steal it away
					 */
					struct task_struct *p;

					for_each_task(p)
						if (p->tty == dev)
							p->tty = -1;
				} else
					return -EPERM;
			}
			current->tty = dev;
			tty->session = current->session;
			tty->pgrp = current->pgrp;
			return 0;
		case TIOCGPGRP:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (pid_t));
			if (retval)
				return retval;
			if (current->tty != termios_dev)
				return -ENOTTY;
			put_fs_long(termios_tty->pgrp, (pid_t *) arg);
			return 0;
		case TIOCSPGRP:
			retval = check_change(termios_tty, termios_dev);
			if (retval)
				return retval;
			if ((current->tty < 0) ||
			    (current->tty != termios_dev) ||
			    (termios_tty->session != current->session))
				return -ENOTTY;
			pgrp = get_fs_long((pid_t *) arg);
			if (pgrp < 0)
				return -EINVAL;
			if (session_of_pgrp(pgrp) != current->session)
				return -EPERM;
			termios_tty->pgrp = pgrp;
			return 0;
		case TIOCOUTQ:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (unsigned long));
			if (retval)
				return retval;
			put_fs_long(CHARS(&tty->write_q),
				    (unsigned long *) arg);
			return 0;
		case TIOCINQ:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (unsigned long));
			if (retval)
				return retval;
			if (L_ICANON(tty))
				put_fs_long(inq_canon(tty),
					(unsigned long *) arg);
			else
				put_fs_long(CHARS(&tty->secondary),
					(unsigned long *) arg);
			return 0;
		case TIOCSTI:
			if ((current->tty != dev) && !suser())
				return -EPERM;
			retval = verify_area(VERIFY_READ, (void *) arg, 1);
			if (retval)
				return retval;
			put_tty_queue(get_fs_byte((char *) arg), &tty->read_q);
			TTY_READ_FLUSH(tty);
			return 0;
		case TIOCGWINSZ:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (struct winsize));
			if (retval)
				return retval;
			memcpy_tofs((struct winsize *) arg, &tty->winsize,
				    sizeof (struct winsize));
			return 0;
		case TIOCSWINSZ:
			if (IS_A_PTY_MASTER(dev))
				set_window_size(other_tty,(struct winsize *) arg);
			return set_window_size(tty,(struct winsize *) arg);
		case TIOCLINUX:
			switch (get_fs_byte((char *)arg))
			{
				case 0: 
					return do_screendump(arg);
				case 1: 
					return do_get_ps_info(arg);
#ifdef CONFIG_SELECTION
				case 2:
					return set_selection(arg);
				case 3:
					return paste_selection(tty);
				case 4:
					unblank_screen();
					return 0;
#endif /* CONFIG_SELECTION */
				default: 
					return -EINVAL;
			}
		case TIOCCONS:
			if (IS_A_CONSOLE(dev)) {
				if (!suser())
					return -EPERM;
				redirect = NULL;
				return 0;
			}
			if (redirect)
				return -EBUSY;
			if (!suser())
				return -EPERM;
			if (IS_A_PTY_MASTER(dev))
				redirect = other_tty;
			else if (IS_A_PTY_SLAVE(dev))
				redirect = tty;
			else
				return -ENOTTY;
			return 0;
		case FIONBIO:
			arg = get_fs_long((unsigned long *) arg);
			if (arg)
				file->f_flags |= O_NONBLOCK;
			else
				file->f_flags &= ~O_NONBLOCK;
			return 0;
		case TIOCNOTTY:
			if (current->tty != dev)
				return -ENOTTY;
			if (current->leader)
				disassociate_ctty(0);
			current->tty = -1;
			return 0;
		case TIOCGETD:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (unsigned long));
			if (retval)
				return retval;
			put_fs_long(tty->disc, (unsigned long *) arg);
			return 0;
		case TIOCSETD:
			retval = check_change(tty, dev);
			if (retval)
				return retval;
			arg = get_fs_long((unsigned long *) arg);
			return tty_set_ldisc(tty, arg);
		case TIOCGLCKTRMIOS:
			arg = get_fs_long((unsigned long *) arg);
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (struct termios));
			if (retval)
				return retval;
			memcpy_tofs((struct termios *) arg,
				    &termios_locked[termios_dev],
				    sizeof (struct termios));
			return 0;
		case TIOCSLCKTRMIOS:
			if (!suser())
				return -EPERM;
			arg = get_fs_long((unsigned long *) arg);
			memcpy_fromfs(&termios_locked[termios_dev],
				      (struct termios *) arg,
				      sizeof (struct termios));
			return 0;
		case TIOCPKT:
			if (!IS_A_PTY_MASTER(dev))
				return -ENOTTY;
			retval = verify_area(VERIFY_READ, (void *) arg,
					     sizeof (unsigned long));
			if (retval)
				return retval;
			if (get_fs_long(arg)) {
				if (!tty->packet) {
					tty->packet = 1;
					tty->link->ctrl_status = 0;
				}
			} else
				tty->packet = 0;
			return 0;
		case TCSBRK: case TCSBRKP:
			retval = check_change(tty, dev);
			if (retval)
				return retval;
			wait_until_sent(tty, 0);
			if (!tty->ioctl)
				return 0;
			tty->ioctl(tty, file, cmd, arg);
			return 0;
		default:
			if (tty->ioctl) {
				retval = (tty->ioctl)(tty, file, cmd, arg);
				if (retval != -EINVAL)
					return retval;
			}
			if (ldiscs[tty->disc].ioctl) {
				retval = (ldiscs[tty->disc].ioctl)
					(tty, file, cmd, arg);
				return retval;
			}
			return -EINVAL;
	}
}