tty_io.c

powerpc内核mpc8241linux系统下char驱动程序

 * Split this up, as gcc can choke on it otherwise..
 */
int tty_ioctl(struct inode * inode, struct file * file,
	      unsigned int cmd, unsigned long arg)
{
	struct tty_struct *tty, *real_tty;
	int retval;
	
	tty = (struct tty_struct *)file->private_data;
	if (tty_paranoia_check(tty, inode->i_rdev, "tty_ioctl"))
		return -EINVAL;

	real_tty = tty;
	if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
	    tty->driver.subtype == PTY_TYPE_MASTER)
		real_tty = tty->link;

	/*
	 * Break handling by driver
	 */
	if (!tty->driver.break_ctl) {
		switch(cmd) {
		case TIOCSBRK:
		case TIOCCBRK:
			if (tty->driver.ioctl)
				return tty->driver.ioctl(tty, file, cmd, arg);
			return -EINVAL;
			
		/* These two ioctl's always return success; even if */
		/* the driver doesn't support them. */
		case TCSBRK:
		case TCSBRKP:
			if (!tty->driver.ioctl)
				return 0;
			retval = tty->driver.ioctl(tty, file, cmd, arg);
			if (retval == -ENOIOCTLCMD)
				retval = 0;
			return retval;
		}
	}

	/*
	 * Factor out some common prep work
	 */
	switch (cmd) {
	case TIOCSETD:
	case TIOCSBRK:
	case TIOCCBRK:
	case TCSBRK:
	case TCSBRKP:			
		retval = tty_check_change(tty);
		if (retval)
			return retval;
		if (cmd != TIOCCBRK) {
			tty_wait_until_sent(tty, 0);
			if (signal_pending(current))
				return -EINTR;
		}
		break;
	}

	switch (cmd) {
		case TIOCSTI:
			return tiocsti(tty, (char *)arg);
		case TIOCGWINSZ:
			return tiocgwinsz(tty, (struct winsize *) arg);
		case TIOCSWINSZ:
			return tiocswinsz(tty, real_tty, (struct winsize *) arg);
		case TIOCCONS:
			return tioccons(tty, real_tty);
		case FIONBIO:
			return fionbio(file, (int *) arg);
		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:
			return tiocsctty(tty, arg);
		case TIOCGPGRP:
			return tiocgpgrp(tty, real_tty, (pid_t *) arg);
		case TIOCSPGRP:
			return tiocspgrp(tty, real_tty, (pid_t *) arg);
		case TIOCGSID:
			return tiocgsid(tty, real_tty, (pid_t *) arg);
		case TIOCGETD:
			return put_user(tty->ldisc.num, (int *) arg);
		case TIOCSETD:
			return tiocsetd(tty, (int *) arg);
#ifdef CONFIG_VT
		case TIOCLINUX:
			return tioclinux(tty, arg);
#endif
		case TIOCTTYGSTRUCT:
			return tiocttygstruct(tty, (struct tty_struct *) arg);

		/*
		 * Break handling
		 */
		case TIOCSBRK:	/* Turn break on, unconditionally */
			tty->driver.break_ctl(tty, -1);
			return 0;
			
		case TIOCCBRK:	/* Turn break off, unconditionally */
			tty->driver.break_ctl(tty, 0);
			return 0;
		case TCSBRK:   /* SVID version: non-zero arg --> no break */
			/*
			 * XXX is the above comment correct, or the
			 * code below correct?  Is this ioctl used at
			 * all by anyone?
			 */
			if (!arg)
				return send_break(tty, HZ/4);
			return 0;
		case TCSBRKP:	/* support for POSIX tcsendbreak() */	
			return send_break(tty, arg ? arg*(HZ/10) : HZ/4);
	}
	if (tty->driver.ioctl) {
		int retval = (tty->driver.ioctl)(tty, file, cmd, arg);
		if (retval != -ENOIOCTLCMD)
			return retval;
	}
	if (tty->ldisc.ioctl) {
		int 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);
	read_lock(&tasklist_lock);
	for_each_task(p) {
		if ((p->tty == tty) ||
		    ((session > 0) && (p->session == session)))
			send_sig(SIGKILL, p, 1);
		else if (p->files) {
			for (i=0; i < p->files->max_fds; i++) {
				filp = fcheck_task(p, i);
				if (filp && (filp->f_op == &tty_fops) &&
				    (filp->private_data == tty)) {
					send_sig(SIGKILL, p, 1);
					break;
				}
			}
		}
	}
	read_unlock(&tasklist_lock);
#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;
	unsigned long flags;

	if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
		queue_task(&tty->flip.tqueue, &tq_timer);
		return;
	}
	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;

		save_flags(flags); 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;

		save_flags(flags); 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;
	restore_flags(flags);
	
	tty->ldisc.receive_buf(tty, cp, fp, count);
}

/*
 * Routine which returns the baud rate of the tty
 *
 * Note that the baud_table needs to be kept in sync with the
 * include/asm/termbits.h file.
 */
static int baud_table[] = {
	0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
	9600, 19200, 38400, 57600, 115200, 230400, 460800,
#ifdef __sparc__
	76800, 153600, 307200, 614400, 921600
#else
	500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
	2500000, 3000000, 3500000, 4000000
#endif
};

static int n_baud_table = sizeof(baud_table)/sizeof(int);

int tty_get_baud_rate(struct tty_struct *tty)
{
	unsigned int cflag, i;

	cflag = tty->termios->c_cflag;

	i = cflag & CBAUD;
	if (i & CBAUDEX) {
		i &= ~CBAUDEX;
		if (i < 1 || i+15 >= n_baud_table) 
			tty->termios->c_cflag &= ~CBAUDEX;
		else
			i += 15;
	}
	if (i==15 && tty->alt_speed) {
		if (!tty->warned) {
			printk("Use of setserial/setrocket to set SPD_* flags is deprecated\n");
			tty->warned = 1;
		}
		return(tty->alt_speed);
	}
	
	return baud_table[i];
}

void tty_flip_buffer_push(struct tty_struct *tty)
{
	if (tty->low_latency)
		flush_to_ldisc((void *) tty);
	else
		queue_task(&tty->flip.tqueue, &tq_timer);
}

/*
 * 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;
	tty->flip.pty_sem = MUTEX;
	tty->tq_hangup.routine = do_tty_hangup;
	tty->tq_hangup.data = tty;
	sema_init(&tty->atomic_read, 1);
}

/*
 * 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;
	
	proc_tty_register_driver(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;

	proc_tty_unregister_driver(driver);
	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 __init 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..
	 */
#ifdef CONFIG_VT
	kmem_start = con_init(kmem_start);
#endif
#ifdef CONFIG_SERIAL_CONSOLE
#ifdef CONFIG_8xx
	kmem_start = console_8xx_init(kmem_start, kmem_end);
#else 	
	kmem_start = serial_console_init(kmem_start, kmem_end);
#endif /* CONFIG_8xx */
#endif
	return kmem_start;
}

static struct tty_driver dev_tty_driver, dev_syscons_driver;
#ifdef CONFIG_UNIX98_PTYS
static struct tty_driver dev_ptmx_driver;
#endif
#ifdef CONFIG_VT
static struct tty_driver dev_console_driver;
#endif

/*
 * Ok, now we can initialize the rest of the tty devices and can count
 * on memory allocations, interrupts etc..
 */
__initfunc(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.driver_name = "/dev/tty";
	dev_tty_driver.name = dev_tty_driver.driver_name + 5;
	dev_tty_driver.name_base = 0;
	dev_tty_driver.major = TTYAUX_MAJOR;
	dev_tty_driver.minor_start = 0;
	dev_tty_driver.num = 1;
	dev_tty_driver.type = TTY_DRIVER_TYPE_SYSTEM;
	dev_tty_driver.subtype = SYSTEM_TYPE_TTY;
	
	if (tty_register_driver(&dev_tty_driver))
		panic("Couldn't register /dev/tty driver\n");

	dev_syscons_driver = dev_tty_driver;
	dev_syscons_driver.driver_name = "/dev/console";
	dev_syscons_driver.name = dev_syscons_driver.driver_name + 5;
	dev_syscons_driver.major = TTYAUX_MAJOR;
	dev_syscons_driver.minor_start = 1;
	dev_syscons_driver.type = TTY_DRIVER_TYPE_SYSTEM;
	dev_syscons_driver.subtype = SYSTEM_TYPE_SYSCONS;

	if (tty_register_driver(&dev_syscons_driver))
		panic("Couldn't register /dev/console driver\n");

#ifdef CONFIG_UNIX98_PTYS
	dev_ptmx_driver = dev_tty_driver;
	dev_ptmx_driver.driver_name = "/dev/ptmx";
	dev_ptmx_driver.name = dev_ptmx_driver.driver_name + 5;
	dev_ptmx_driver.major= MAJOR(PTMX_DEV);
	dev_ptmx_driver.minor_start = MINOR(PTMX_DEV);
	dev_ptmx_driver.type = TTY_DRIVER_TYPE_SYSTEM;
	dev_ptmx_driver.subtype = SYSTEM_TYPE_SYSPTMX;

	if (tty_register_driver(&dev_ptmx_driver))
		panic("Couldn't register /dev/ptmx driver\n");
#endif
	
#ifdef CONFIG_VT
	dev_console_driver = dev_tty_driver;
	dev_console_driver.driver_name = "/dev/tty0";
	dev_console_driver.name = dev_console_driver.driver_name + 5;
	dev_console_driver.major = TTY_MAJOR;
	dev_console_driver.type = TTY_DRIVER_TYPE_SYSTEM;
	dev_console_driver.subtype = SYSTEM_TYPE_CONSOLE;

	if (tty_register_driver(&dev_console_driver))
		panic("Couldn't register /dev/tty0 driver\n");

#if !defined(CONFIG_STANDALONE) /* ebony */
	kbd_init();
#endif

#endif
#ifdef CONFIG_ESPSERIAL  /* init ESP before rs, so rs doesn't see the port */
	espserial_init();
#endif
#ifdef CONFIG_SERIAL
	rs_init();
#endif
#ifdef CONFIG_MAC_SERIAL
	macserial_init();
#endif
#ifdef CONFIG_ROCKETPORT
	rp_init();
#endif
#ifdef CONFIG_MVME16x
	serial167_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_DIGIEPCA
	pc_init();
#endif
#ifdef CONFIG_RISCOM8
	riscom8_init();
#endif
#ifdef CONFIG_SPECIALIX
	specialix_init();
#endif
#ifdef CONFIG_8xx
        rs_8xx_init();
#endif /* CONFIG_8xx */
	pty_init();
#ifdef CONFIG_VT
	vcs_init();
#endif
	return 0;
}