tty_io.c

unix/linux 编程实践一书的所有源代码

			if (retval)
				return retval;
			ch = get_user((char *) arg);
			tty->ldisc.receive_buf(tty, &ch, &mbz, 1);
			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:
			retval = verify_area(VERIFY_READ, (void *) arg,
					     sizeof (struct winsize));
			if (retval)
				return retval;			
			memcpy_fromfs(&tmp_ws, (struct winsize *) arg,
				      sizeof (struct winsize));
			if (memcmp(&tmp_ws, &tty->winsize,
				   sizeof(struct winsize))) {
				if (tty->pgrp > 0)
					kill_pg(tty->pgrp, SIGWINCH, 1);
				if ((real_tty->pgrp != tty->pgrp) &&
				    (real_tty->pgrp > 0))
					kill_pg(real_tty->pgrp, SIGWINCH, 1);
			}
			tty->winsize = tmp_ws;
			real_tty->winsize = tmp_ws;
			return 0;
		case TIOCCONS:
			if (tty->driver.type == TTY_DRIVER_TYPE_CONSOLE) {
				if (!suser())
					return -EPERM;
				redirect = NULL;
				return 0;
			}
			if (redirect)
				return -EBUSY;
			redirect = real_tty;
			return 0;
		case FIONBIO:
			retval = verify_area(VERIFY_READ, (void *) arg, sizeof(int));
			if (retval)
				return retval;
			arg = get_user((unsigned int *) arg);
			if (arg)
				file->f_flags |= O_NONBLOCK;
			else
				file->f_flags &= ~O_NONBLOCK;
			return 0;
		case TIOCEXCL:
			set_bit(TTY_EXCLUSIVE, &tty->flags);
			return 0;
		case TIOCNXCL:
			clear_bit(TTY_EXCLUSIVE, &tty->flags);
			return 0;
		case TIOCNOTTY:
			if (current->tty != tty)
				return -ENOTTY;
			if (current->leader)
				disassociate_ctty(0);
			current->tty = NULL;
			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)
				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 == tty)
							p->tty = NULL;
				} else
					return -EPERM;
			}
			current->tty = tty;
			current->tty_old_pgrp = 0;
			tty->session = current->session;
			tty->pgrp = current->pgrp;
			return 0;
		case TIOCGPGRP:
			/*
			 * (tty == real_tty) is a cheap way of
			 * testing if the tty is NOT a master pty.
			 */
			if (tty == real_tty && current->tty != real_tty)
				return -ENOTTY;
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (pid_t));
			if (retval)
				return retval;
			put_user(real_tty->pgrp, (pid_t *) arg);
			return 0;
		case TIOCSPGRP:
			retval = tty_check_change(real_tty);
			if (retval == -EIO)
				return -ENOTTY;
			if (retval)
				return retval;
			if (!current->tty ||
			    (current->tty != real_tty) ||
			    (real_tty->session != current->session))
				return -ENOTTY;
			pgrp = get_user((pid_t *) arg);
			if (pgrp < 0)
				return -EINVAL;
			if (session_of_pgrp(pgrp) != current->session)
				return -EPERM;
			real_tty->pgrp = pgrp;
			return 0;
		case TIOCGETD:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
					     sizeof (int));
			if (retval)
				return retval;
			put_user(tty->ldisc.num, (int *) arg);
			return 0;
		case TIOCSETD:
			retval = tty_check_change(tty);
			if (retval)
				return retval;
			retval = verify_area(VERIFY_READ, (void *) arg,
					     sizeof (int));
			if (retval)
				return retval;
			arg = get_user((int *) arg);
			return tty_set_ldisc(tty, arg);
		case TIOCLINUX:
			if (tty->driver.type != TTY_DRIVER_TYPE_CONSOLE)
				return -EINVAL;
			if (current->tty != tty && !suser())
				return -EPERM;
			retval = verify_area(VERIFY_READ, (void *) arg, 1);
			if (retval)
				return retval;
			switch (retval = get_user((char *)arg))
			{
				case 0:
				case 8:
				case 9:
					printk("TIOCLINUX (0/8/9) ioctl is gone - use /dev/vcs\n");
					return -EINVAL;
#if 0
				case 1:
					printk("Deprecated TIOCLINUX (1) ioctl\n");
					return do_get_ps_info(arg);
#endif
				case 2:
					return set_selection(arg, tty, 1);
				case 3:
					return paste_selection(tty);
				case 4:
					do_unblank_screen();
					return 0;
				case 5:
					return sel_loadlut(arg);
				case 6:
			/*
			 * Make it possible to react to Shift+Mousebutton.
			 * Note that 'shift_state' is an undocumented
			 * kernel-internal variable; programs not closely
			 * related to the kernel should not use this.
			 */
					retval = verify_area(VERIFY_WRITE, (void *) arg, 1);
					if (retval)
						return retval;
					put_user(shift_state,(char *) arg);
					return 0;
				case 7:
					retval = verify_area(VERIFY_WRITE, (void *) arg, 1);
					if (retval)
						return retval;
					put_user(mouse_reporting(),(char *) arg);
					return 0;
				case 10:
					set_vesa_blanking(arg);
					return 0;
				case 11:	/* set kmsg redirect */
					if (!suser())
						return -EPERM;
					retval = verify_area(VERIFY_READ,
						(void *) arg+1, 1);
					if (retval)
						return retval;
					kmsg_redirect = get_user((char *)arg+1);
					return 0;
				case 12:	/* get fg_console */
					return fg_console;
				default: 
					return -EINVAL;
			}

		case TIOCTTYGSTRUCT:
			retval = verify_area(VERIFY_WRITE, (void *) arg,
						sizeof(struct tty_struct));
			if (retval)
				return retval;
			memcpy_tofs((struct tty_struct *) arg,
				    tty, sizeof(struct tty_struct));
			return 0;
		default:
			if (tty->driver.ioctl) {
				retval = (tty->driver.ioctl)(tty, file,
							     cmd, arg);
				if (retval != -ENOIOCTLCMD)
					return retval;
			}
			if (tty->ldisc.ioctl) {
				retval = (tty->ldisc.ioctl)(tty, file,
							    cmd, arg);
				if (retval != -ENOIOCTLCMD)
					return retval;
			}
			return -EINVAL;
		}
}


/*
 * This implements the "Secure Attention Key" ---  the idea is to
 * prevent trojan horses by killing all processes associated with this
 * tty when the user hits the "Secure Attention Key".  Required for
 * super-paranoid applications --- see the Orange Book for more details.
 * 
 * This code could be nicer; ideally it should send a HUP, wait a few
 * seconds, then send a INT, and then a KILL signal.  But you then
 * have to coordinate with the init process, since all processes associated
 * with the current tty must be dead before the new getty is allowed
 * to spawn.
 */
void do_SAK( struct tty_struct *tty)
{
#ifdef TTY_SOFT_SAK
	tty_hangup(tty);
#else
	struct task_struct **p;
	int session;
	int		i;
	struct file	*filp;
	
	if (!tty)
		return;
	session  = tty->session;
	if (tty->ldisc.flush_buffer)
		tty->ldisc.flush_buffer(tty);
	if (tty->driver.flush_buffer)
		tty->driver.flush_buffer(tty);
 	for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
		if (!(*p))
			continue;
		if (((*p)->tty == tty) ||
		    ((session > 0) && ((*p)->session == session)))
			send_sig(SIGKILL, *p, 1);
		else if ((*p)->files) {
			for (i=0; i < NR_OPEN; i++) {
				filp = (*p)->files->fd[i];
				if (filp && (filp->f_op == &tty_fops) &&
				    (filp->private_data == tty)) {
					send_sig(SIGKILL, *p, 1);
					break;
				}
			}
		}
	}
#endif
}

/*
 * This routine is called out of the software interrupt to flush data
 * from the flip buffer to the line discipline.
 */
static void flush_to_ldisc(void *private_)
{
	struct tty_struct *tty = (struct tty_struct *) private_;
	unsigned char	*cp;
	char		*fp;
	int		count;

	if (tty->flip.buf_num) {
		cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
		fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
		tty->flip.buf_num = 0;

		cli();
		tty->flip.char_buf_ptr = tty->flip.char_buf;
		tty->flip.flag_buf_ptr = tty->flip.flag_buf;
	} else {
		cp = tty->flip.char_buf;
		fp = tty->flip.flag_buf;
		tty->flip.buf_num = 1;

		cli();
		tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
		tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
	}
	count = tty->flip.count;
	tty->flip.count = 0;
	sti();
	
#if 0
	if (count > tty->max_flip_cnt)
		tty->max_flip_cnt = count;
#endif
	tty->ldisc.receive_buf(tty, cp, fp, count);
}

/*
 * This subroutine initializes a tty structure.
 */
static void initialize_tty_struct(struct tty_struct *tty)
{
	memset(tty, 0, sizeof(struct tty_struct));
	tty->magic = TTY_MAGIC;
	tty->ldisc = ldiscs[N_TTY];
	tty->pgrp = -1;
	tty->flip.char_buf_ptr = tty->flip.char_buf;
	tty->flip.flag_buf_ptr = tty->flip.flag_buf;
	tty->flip.tqueue.routine = flush_to_ldisc;
	tty->flip.tqueue.data = tty;
}

/*
 * The default put_char routine if the driver did not define one.
 */
void tty_default_put_char(struct tty_struct *tty, unsigned char ch)
{
	tty->driver.write(tty, 0, &ch, 1);
}

/*
 * Called by a tty driver to register itself.
 */
int tty_register_driver(struct tty_driver *driver)
{
	int error;

	if (driver->flags & TTY_DRIVER_INSTALLED)
		return 0;

	error = register_chrdev(driver->major, driver->name, &tty_fops);
	if (error < 0)
		return error;
	else if(driver->major == 0)
		driver->major = error;

	if (!driver->put_char)
		driver->put_char = tty_default_put_char;
	
	driver->prev = 0;
	driver->next = tty_drivers;
	if (tty_drivers) tty_drivers->prev = driver;
	tty_drivers = driver;
	return error;
}

/*
 * Called by a tty driver to unregister itself.
 */
int tty_unregister_driver(struct tty_driver *driver)
{
	int	retval;
	struct tty_driver *p;
	int	found = 0;
	const char *othername = NULL;
	
	if (*driver->refcount)
		return -EBUSY;

	for (p = tty_drivers; p; p = p->next) {
		if (p == driver)
			found++;
		else if (p->major == driver->major)
			othername = p->name;
	}
	
	if (!found)
		return -ENOENT;

	if (othername == NULL) {
		retval = unregister_chrdev(driver->major, driver->name);
		if (retval)
			return retval;
	} else
		register_chrdev(driver->major, othername, &tty_fops);

	if (driver->prev)
		driver->prev->next = driver->next;
	else
		tty_drivers = driver->next;
	
	if (driver->next)
		driver->next->prev = driver->prev;

	return 0;
}


/*
 * Initialize the console device. This is called *early*, so
 * we can't necessarily depend on lots of kernel help here.
 * Just do some early initializations, and do the complex setup
 * later.
 */
long console_init(long kmem_start, long kmem_end)
{
	/* Setup the default TTY line discipline. */
	memset(ldiscs, 0, sizeof(ldiscs));
	(void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY);

	/*
	 * Set up the standard termios.  Individual tty drivers may 
	 * deviate from this; this is used as a template.
	 */
	memset(&tty_std_termios, 0, sizeof(struct termios));
	memcpy(tty_std_termios.c_cc, INIT_C_CC, NCCS);
	tty_std_termios.c_iflag = ICRNL | IXON;
	tty_std_termios.c_oflag = OPOST | ONLCR;
	tty_std_termios.c_cflag = B38400 | CS8 | CREAD | HUPCL;
	tty_std_termios.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
		ECHOCTL | ECHOKE | IEXTEN;

	/*
	 * set up the console device so that later boot sequences can 
	 * inform about problems etc..
	 */
	return con_init(kmem_start);
}

static struct tty_driver dev_tty_driver, dev_console_driver;

/*
 * Ok, now we can initialize the rest of the tty devices and can count
 * on memory allocations, interrupts etc..
 */
int tty_init(void)
{
	if (sizeof(struct tty_struct) > PAGE_SIZE)
		panic("size of tty structure > PAGE_SIZE!");

	/*
	 * dev_tty_driver and dev_console_driver are actually magic
	 * devices which get redirected at open time.  Nevertheless,
	 * we register them so that register_chrdev is called
	 * appropriately.
	 */
	memset(&dev_tty_driver, 0, sizeof(struct tty_driver));
	dev_tty_driver.magic = TTY_DRIVER_MAGIC;
	dev_tty_driver.name = "tty";
	dev_tty_driver.name_base = 0;
	dev_tty_driver.major = TTY_MAJOR;
	dev_tty_driver.minor_start = 0;
	dev_tty_driver.num = 1;
	
	if (tty_register_driver(&dev_tty_driver))
		panic("Couldn't register /dev/tty driver\n");

	dev_console_driver = dev_tty_driver;
	dev_console_driver.name = "console";
	dev_console_driver.major = TTYAUX_MAJOR;

	if (tty_register_driver(&dev_console_driver))
		panic("Couldn't register /dev/console driver\n");
	
	kbd_init();
#ifdef CONFIG_SERIAL
	rs_init();
#endif
#ifdef CONFIG_SCC
	scc_init();
#endif
#ifdef CONFIG_CYCLADES
	cy_init();
#endif
#ifdef CONFIG_STALLION
	stl_init();
#endif
#ifdef CONFIG_ISTALLION
	stli_init();
#endif
#ifdef CONFIG_DIGI
	pcxe_init();
#endif
#ifdef CONFIG_RISCOM8
	riscom8_init();
#endif
#ifdef CONFIG_BAYCOM
	baycom_init();
#endif
#ifdef CONFIG_SPECIALIX
	specialix_init();
#endif
	pty_init();
	vcs_init();
	return 0;
}