TTY: create drivers/tty and move the tty core files there

The tty code should be in its own subdirectory and not in the char
driver with all of the cruft that is currently there.

Based on work done by Arnd Bergmann <arnd@arndb.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 0 insertions, 3263 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
deleted file mode 100644
index c05c5af5aa0..00000000000
--- a/drivers/char/tty_io.c
+++ /dev/null
@@ -1,3263 +0,0 @@
-/*
- *  linux/drivers/char/tty_io.c
- *
- *  Copyright (C) 1991, 1992  Linus Torvalds
- */
-
-/*
- * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
- * or rs-channels. It also implements echoing, cooked mode etc.
- *
- * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
- *
- * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
- * tty_struct and tty_queue structures.  Previously there was an array
- * of 256 tty_struct's which was statically allocated, and the
- * tty_queue structures were allocated at boot time.  Both are now
- * dynamically allocated only when the tty is open.
- *
- * Also restructured routines so that there is more of a separation
- * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
- * the low-level tty routines (serial.c, pty.c, console.c).  This
- * makes for cleaner and more compact code.  -TYT, 9/17/92
- *
- * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
- * which can be dynamically activated and de-activated by the line
- * discipline handling modules (like SLIP).
- *
- * NOTE: pay no attention to the line discipline code (yet); its
- * interface is still subject to change in this version...
- * -- TYT, 1/31/92
- *
- * Added functionality to the OPOST tty handling.  No delays, but all
- * other bits should be there.
- *	-- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
- *
- * Rewrote canonical mode and added more termios flags.
- * 	-- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
- *
- * Reorganized FASYNC support so mouse code can share it.
- *	-- ctm@ardi.com, 9Sep95
- *
- * New TIOCLINUX variants added.
- *	-- mj@k332.feld.cvut.cz, 19-Nov-95
- *
- * Restrict vt switching via ioctl()
- *      -- grif@cs.ucr.edu, 5-Dec-95
- *
- * Move console and virtual terminal code to more appropriate files,
- * implement CONFIG_VT and generalize console device interface.
- *	-- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
- *
- * Rewrote tty_init_dev and tty_release_dev to eliminate races.
- *	-- Bill Hawes <whawes@star.net>, June 97
- *
- * Added devfs support.
- *      -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
- *
- * Added support for a Unix98-style ptmx device.
- *      -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
- *
- * Reduced memory usage for older ARM systems
- *      -- Russell King <rmk@arm.linux.org.uk>
- *
- * Move do_SAK() into process context.  Less stack use in devfs functions.
- * alloc_tty_struct() always uses kmalloc()
- *			 -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
- */
-
-#include <linux/types.h>
-#include <linux/major.h>
-#include <linux/errno.h>
-#include <linux/signal.h>
-#include <linux/fcntl.h>
-#include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/tty.h>
-#include <linux/tty_driver.h>
-#include <linux/tty_flip.h>
-#include <linux/devpts_fs.h>
-#include <linux/file.h>
-#include <linux/fdtable.h>
-#include <linux/console.h>
-#include <linux/timer.h>
-#include <linux/ctype.h>
-#include <linux/kd.h>
-#include <linux/mm.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/poll.h>
-#include <linux/proc_fs.h>
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/smp_lock.h>
-#include <linux/device.h>
-#include <linux/wait.h>
-#include <linux/bitops.h>
-#include <linux/delay.h>
-#include <linux/seq_file.h>
-#include <linux/serial.h>
-
-#include <linux/uaccess.h>
-#include <asm/system.h>
-
-#include <linux/kbd_kern.h>
-#include <linux/vt_kern.h>
-#include <linux/selection.h>
-
-#include <linux/kmod.h>
-#include <linux/nsproxy.h>
-
-#undef TTY_DEBUG_HANGUP
-
-#define TTY_PARANOIA_CHECK 1
-#define CHECK_TTY_COUNT 1
-
-struct ktermios tty_std_termios = {	/* for the benefit of tty drivers  */
-	.c_iflag = ICRNL | IXON,
-	.c_oflag = OPOST | ONLCR,
-	.c_cflag = B38400 | CS8 | CREAD | HUPCL,
-	.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
-		   ECHOCTL | ECHOKE | IEXTEN,
-	.c_cc = INIT_C_CC,
-	.c_ispeed = 38400,
-	.c_ospeed = 38400
-};
-
-EXPORT_SYMBOL(tty_std_termios);
-
-/* This list gets poked at by procfs and various bits of boot up code. This
-   could do with some rationalisation such as pulling the tty proc function
-   into this file */
-
-LIST_HEAD(tty_drivers);			/* linked list of tty drivers */
-
-/* Mutex to protect creating and releasing a tty. This is shared with
-   vt.c for deeply disgusting hack reasons */
-DEFINE_MUTEX(tty_mutex);
-EXPORT_SYMBOL(tty_mutex);
-
-/* Spinlock to protect the tty->tty_files list */
-DEFINE_SPINLOCK(tty_files_lock);
-
-static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
-static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
-ssize_t redirected_tty_write(struct file *, const char __user *,
-							size_t, loff_t *);
-static unsigned int tty_poll(struct file *, poll_table *);
-static int tty_open(struct inode *, struct file *);
-long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
-#ifdef CONFIG_COMPAT
-static long tty_compat_ioctl(struct file *file, unsigned int cmd,
-				unsigned long arg);
-#else
-#define tty_compat_ioctl NULL
-#endif
-static int __tty_fasync(int fd, struct file *filp, int on);
-static int tty_fasync(int fd, struct file *filp, int on);
-static void release_tty(struct tty_struct *tty, int idx);
-static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
-static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
-
-/**
- *	alloc_tty_struct	-	allocate a tty object
- *
- *	Return a new empty tty structure. The data fields have not
- *	been initialized in any way but has been zeroed
- *
- *	Locking: none
- */
-
-struct tty_struct *alloc_tty_struct(void)
-{
-	return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
-}
-
-/**
- *	free_tty_struct		-	free a disused tty
- *	@tty: tty struct to free
- *
- *	Free the write buffers, tty queue and tty memory itself.
- *
- *	Locking: none. Must be called after tty is definitely unused
- */
-
-void free_tty_struct(struct tty_struct *tty)
-{
-	if (tty->dev)
-		put_device(tty->dev);
-	kfree(tty->write_buf);
-	tty_buffer_free_all(tty);
-	kfree(tty);
-}
-
-static inline struct tty_struct *file_tty(struct file *file)
-{
-	return ((struct tty_file_private *)file->private_data)->tty;
-}
-
-/* Associate a new file with the tty structure */
-int tty_add_file(struct tty_struct *tty, struct file *file)
-{
-	struct tty_file_private *priv;
-
-	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-
-	priv->tty = tty;
-	priv->file = file;
-	file->private_data = priv;
-
-	spin_lock(&tty_files_lock);
-	list_add(&priv->list, &tty->tty_files);
-	spin_unlock(&tty_files_lock);
-
-	return 0;
-}
-
-/* Delete file from its tty */
-void tty_del_file(struct file *file)
-{
-	struct tty_file_private *priv = file->private_data;
-
-	spin_lock(&tty_files_lock);
-	list_del(&priv->list);
-	spin_unlock(&tty_files_lock);
-	file->private_data = NULL;
-	kfree(priv);
-}
-
-
-#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
-
-/**
- *	tty_name	-	return tty naming
- *	@tty: tty structure
- *	@buf: buffer for output
- *
- *	Convert a tty structure into a name. The name reflects the kernel
- *	naming policy and if udev is in use may not reflect user space
- *
- *	Locking: none
- */
-
-char *tty_name(struct tty_struct *tty, char *buf)
-{
-	if (!tty) /* Hmm.  NULL pointer.  That's fun. */
-		strcpy(buf, "NULL tty");
-	else
-		strcpy(buf, tty->name);
-	return buf;
-}
-
-EXPORT_SYMBOL(tty_name);
-
-int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
-			      const char *routine)
-{
-#ifdef TTY_PARANOIA_CHECK
-	if (!tty) {
-		printk(KERN_WARNING
-			"null TTY for (%d:%d) in %s\n",
-			imajor(inode), iminor(inode), routine);
-		return 1;
-	}
-	if (tty->magic != TTY_MAGIC) {
-		printk(KERN_WARNING
-			"bad magic number for tty struct (%d:%d) in %s\n",
-			imajor(inode), iminor(inode), routine);
-		return 1;
-	}
-#endif
-	return 0;
-}
-
-static int check_tty_count(struct tty_struct *tty, const char *routine)
-{
-#ifdef CHECK_TTY_COUNT
-	struct list_head *p;
-	int count = 0;
-
-	spin_lock(&tty_files_lock);
-	list_for_each(p, &tty->tty_files) {
-		count++;
-	}
-	spin_unlock(&tty_files_lock);
-	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
-	    tty->driver->subtype == PTY_TYPE_SLAVE &&
-	    tty->link && tty->link->count)
-		count++;
-	if (tty->count != count) {
-		printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
-				    "!= #fd's(%d) in %s\n",
-		       tty->name, tty->count, count, routine);
-		return count;
-	}
-#endif
-	return 0;
-}
-
-/**
- *	get_tty_driver		-	find device of a tty
- *	@dev_t: device identifier
- *	@index: returns the index of the tty
- *
- *	This routine returns a tty driver structure, given a device number
- *	and also passes back the index number.
- *
- *	Locking: caller must hold tty_mutex
- */
-
-static struct tty_driver *get_tty_driver(dev_t device, int *index)
-{
-	struct tty_driver *p;
-
-	list_for_each_entry(p, &tty_drivers, tty_drivers) {
-		dev_t base = MKDEV(p->major, p->minor_start);
-		if (device < base || device >= base + p->num)
-			continue;
-		*index = device - base;
-		return tty_driver_kref_get(p);
-	}
-	return NULL;
-}
-
-#ifdef CONFIG_CONSOLE_POLL
-
-/**
- *	tty_find_polling_driver	-	find device of a polled tty
- *	@name: name string to match
- *	@line: pointer to resulting tty line nr
- *
- *	This routine returns a tty driver structure, given a name
- *	and the condition that the tty driver is capable of polled
- *	operation.
- */
-struct tty_driver *tty_find_polling_driver(char *name, int *line)
-{
-	struct tty_driver *p, *res = NULL;
-	int tty_line = 0;
-	int len;
-	char *str, *stp;
-
-	for (str = name; *str; str++)
-		if ((*str >= '0' && *str <= '9') || *str == ',')
-			break;
-	if (!*str)
-		return NULL;
-
-	len = str - name;
-	tty_line = simple_strtoul(str, &str, 10);
-
-	mutex_lock(&tty_mutex);
-	/* Search through the tty devices to look for a match */
-	list_for_each_entry(p, &tty_drivers, tty_drivers) {
-		if (strncmp(name, p->name, len) != 0)
-			continue;
-		stp = str;
-		if (*stp == ',')
-			stp++;
-		if (*stp == '\0')
-			stp = NULL;
-
-		if (tty_line >= 0 && tty_line < p->num && p->ops &&
-		    p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
-			res = tty_driver_kref_get(p);
-			*line = tty_line;
-			break;
-		}
-	}
-	mutex_unlock(&tty_mutex);
-
-	return res;
-}
-EXPORT_SYMBOL_GPL(tty_find_polling_driver);
-#endif
-
-/**
- *	tty_check_change	-	check for POSIX terminal changes
- *	@tty: tty to check
- *
- *	If we try to write to, or set the state of, a terminal and we're
- *	not in the foreground, send a SIGTTOU.  If the signal is blocked or
- *	ignored, go ahead and perform the operation.  (POSIX 7.2)
- *
- *	Locking: ctrl_lock
- */
-
-int tty_check_change(struct tty_struct *tty)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	if (current->signal->tty != tty)
-		return 0;
-
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-
-	if (!tty->pgrp) {
-		printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
-		goto out_unlock;
-	}
-	if (task_pgrp(current) == tty->pgrp)
-		goto out_unlock;
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-	if (is_ignored(SIGTTOU))
-		goto out;
-	if (is_current_pgrp_orphaned()) {
-		ret = -EIO;
-		goto out;
-	}
-	kill_pgrp(task_pgrp(current), SIGTTOU, 1);
-	set_thread_flag(TIF_SIGPENDING);
-	ret = -ERESTARTSYS;
-out:
-	return ret;
-out_unlock:
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-	return ret;
-}
-
-EXPORT_SYMBOL(tty_check_change);
-
-static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
-				size_t count, loff_t *ppos)
-{
-	return 0;
-}
-
-static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
-				 size_t count, loff_t *ppos)
-{
-	return -EIO;
-}
-
-/* No kernel lock held - none needed ;) */
-static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
-{
-	return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
-}
-
-static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
-		unsigned long arg)
-{
-	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
-}
-
-static long hung_up_tty_compat_ioctl(struct file *file,
-				     unsigned int cmd, unsigned long arg)
-{
-	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
-}
-
-static const struct file_operations tty_fops = {
-	.llseek		= no_llseek,
-	.read		= tty_read,
-	.write		= tty_write,
-	.poll		= tty_poll,
-	.unlocked_ioctl	= tty_ioctl,
-	.compat_ioctl	= tty_compat_ioctl,
-	.open		= tty_open,
-	.release	= tty_release,
-	.fasync		= tty_fasync,
-};
-
-static const struct file_operations console_fops = {
-	.llseek		= no_llseek,
-	.read		= tty_read,
-	.write		= redirected_tty_write,
-	.poll		= tty_poll,
-	.unlocked_ioctl	= tty_ioctl,
-	.compat_ioctl	= tty_compat_ioctl,
-	.open		= tty_open,
-	.release	= tty_release,
-	.fasync		= tty_fasync,
-};
-
-static const struct file_operations hung_up_tty_fops = {
-	.llseek		= no_llseek,
-	.read		= hung_up_tty_read,
-	.write		= hung_up_tty_write,
-	.poll		= hung_up_tty_poll,
-	.unlocked_ioctl	= hung_up_tty_ioctl,
-	.compat_ioctl	= hung_up_tty_compat_ioctl,
-	.release	= tty_release,
-};
-
-static DEFINE_SPINLOCK(redirect_lock);
-static struct file *redirect;
-
-/**
- *	tty_wakeup	-	request more data
- *	@tty: terminal
- *
- *	Internal and external helper for wakeups of tty. This function
- *	informs the line discipline if present that the driver is ready
- *	to receive more output data.
- */
-
-void tty_wakeup(struct tty_struct *tty)
-{
-	struct tty_ldisc *ld;
-
-	if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
-		ld = tty_ldisc_ref(tty);
-		if (ld) {
-			if (ld->ops->write_wakeup)
-				ld->ops->write_wakeup(tty);
-			tty_ldisc_deref(ld);
-		}
-	}
-	wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
-}
-
-EXPORT_SYMBOL_GPL(tty_wakeup);
-
-/**
- *	__tty_hangup		-	actual handler for hangup events
- *	@work: tty device
- *
- *	This can be called by the "eventd" kernel thread.  That is process
- *	synchronous but doesn't hold any locks, so we need to make sure we
- *	have the appropriate locks for what we're doing.
- *
- *	The hangup event clears any pending redirections onto the hung up
- *	device. It ensures future writes will error and it does the needed
- *	line discipline hangup and signal delivery. The tty object itself
- *	remains intact.
- *
- *	Locking:
- *		BTM
- *		  redirect lock for undoing redirection
- *		  file list lock for manipulating list of ttys
- *		  tty_ldisc_lock from called functions
- *		  termios_mutex resetting termios data
- *		  tasklist_lock to walk task list for hangup event
- *		    ->siglock to protect ->signal/->sighand
- */
-void __tty_hangup(struct tty_struct *tty)
-{
-	struct file *cons_filp = NULL;
-	struct file *filp, *f = NULL;
-	struct task_struct *p;
-	struct tty_file_private *priv;
-	int    closecount = 0, n;
-	unsigned long flags;
-	int refs = 0;
-
-	if (!tty)
-		return;
-
-
-	spin_lock(&redirect_lock);
-	if (redirect && file_tty(redirect) == tty) {
-		f = redirect;
-		redirect = NULL;
-	}
-	spin_unlock(&redirect_lock);
-
-	tty_lock();
-
-	/* inuse_filps is protected by the single tty lock,
-	   this really needs to change if we want to flush the
-	   workqueue with the lock held */
-	check_tty_count(tty, "tty_hangup");
-
-	spin_lock(&tty_files_lock);
-	/* This breaks for file handles being sent over AF_UNIX sockets ? */
-	list_for_each_entry(priv, &tty->tty_files, list) {
-		filp = priv->file;
-		if (filp->f_op->write == redirected_tty_write)
-			cons_filp = filp;
-		if (filp->f_op->write != tty_write)
-			continue;
-		closecount++;
-		__tty_fasync(-1, filp, 0);	/* can't block */
-		filp->f_op = &hung_up_tty_fops;
-	}
-	spin_unlock(&tty_files_lock);
-
-	tty_ldisc_hangup(tty);
-
-	read_lock(&tasklist_lock);
-	if (tty->session) {
-		do_each_pid_task(tty->session, PIDTYPE_SID, p) {
-			spin_lock_irq(&p->sighand->siglock);
-			if (p->signal->tty == tty) {
-				p->signal->tty = NULL;
-				/* We defer the dereferences outside fo
-				   the tasklist lock */
-				refs++;
-			}
-			if (!p->signal->leader) {
-				spin_unlock_irq(&p->sighand->siglock);
-				continue;
-			}
-			__group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
-			__group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
-			put_pid(p->signal->tty_old_pgrp);  /* A noop */
-			spin_lock_irqsave(&tty->ctrl_lock, flags);
-			if (tty->pgrp)
-				p->signal->tty_old_pgrp = get_pid(tty->pgrp);
-			spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-			spin_unlock_irq(&p->sighand->siglock);
-		} while_each_pid_task(tty->session, PIDTYPE_SID, p);
-	}
-	read_unlock(&tasklist_lock);
-
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	clear_bit(TTY_THROTTLED, &tty->flags);
-	clear_bit(TTY_PUSH, &tty->flags);
-	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-	put_pid(tty->session);
-	put_pid(tty->pgrp);
-	tty->session = NULL;
-	tty->pgrp = NULL;
-	tty->ctrl_status = 0;
-	set_bit(TTY_HUPPED, &tty->flags);
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-
-	/* Account for the p->signal references we killed */
-	while (refs--)
-		tty_kref_put(tty);
-
-	/*
-	 * If one of the devices matches a console pointer, we
-	 * cannot just call hangup() because that will cause
-	 * tty->count and state->count to go out of sync.
-	 * So we just call close() the right number of times.
-	 */
-	if (cons_filp) {
-		if (tty->ops->close)
-			for (n = 0; n < closecount; n++)
-				tty->ops->close(tty, cons_filp);
-	} else if (tty->ops->hangup)
-		(tty->ops->hangup)(tty);
-	/*
-	 * We don't want to have driver/ldisc interactions beyond
-	 * the ones we did here. The driver layer expects no
-	 * calls after ->hangup() from the ldisc side. However we
-	 * can't yet guarantee all that.
-	 */
-	set_bit(TTY_HUPPED, &tty->flags);
-	tty_ldisc_enable(tty);
-
-	tty_unlock();
-
-	if (f)
-		fput(f);
-}
-
-static void do_tty_hangup(struct work_struct *work)
-{
-	struct tty_struct *tty =
-		container_of(work, struct tty_struct, hangup_work);
-
-	__tty_hangup(tty);
-}
-
-/**
- *	tty_hangup		-	trigger a hangup event
- *	@tty: tty to hangup
- *
- *	A carrier loss (virtual or otherwise) has occurred on this like
- *	schedule a hangup sequence to run after this event.
- */
-
-void tty_hangup(struct tty_struct *tty)
-{
-#ifdef TTY_DEBUG_HANGUP
-	char	buf[64];
-	printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
-#endif
-	schedule_work(&tty->hangup_work);
-}
-
-EXPORT_SYMBOL(tty_hangup);
-
-/**
- *	tty_vhangup		-	process vhangup
- *	@tty: tty to hangup
- *
- *	The user has asked via system call for the terminal to be hung up.
- *	We do this synchronously so that when the syscall returns the process
- *	is complete. That guarantee is necessary for security reasons.
- */
-
-void tty_vhangup(struct tty_struct *tty)
-{
-#ifdef TTY_DEBUG_HANGUP
-	char	buf[64];
-
-	printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
-#endif
-	__tty_hangup(tty);
-}
-
-EXPORT_SYMBOL(tty_vhangup);
-
-
-/**
- *	tty_vhangup_self	-	process vhangup for own ctty
- *
- *	Perform a vhangup on the current controlling tty
- */
-
-void tty_vhangup_self(void)
-{
-	struct tty_struct *tty;
-
-	tty = get_current_tty();
-	if (tty) {
-		tty_vhangup(tty);
-		tty_kref_put(tty);
-	}
-}
-
-/**
- *	tty_hung_up_p		-	was tty hung up
- *	@filp: file pointer of tty
- *
- *	Return true if the tty has been subject to a vhangup or a carrier
- *	loss
- */
-
-int tty_hung_up_p(struct file *filp)
-{
-	return (filp->f_op == &hung_up_tty_fops);
-}
-
-EXPORT_SYMBOL(tty_hung_up_p);
-
-static void session_clear_tty(struct pid *session)
-{
-	struct task_struct *p;
-	do_each_pid_task(session, PIDTYPE_SID, p) {
-		proc_clear_tty(p);
-	} while_each_pid_task(session, PIDTYPE_SID, p);
-}
-
-/**
- *	disassociate_ctty	-	disconnect controlling tty
- *	@on_exit: true if exiting so need to "hang up" the session
- *
- *	This function is typically called only by the session leader, when
- *	it wants to disassociate itself from its controlling tty.
- *
- *	It performs the following functions:
- * 	(1)  Sends a SIGHUP and SIGCONT to the foreground process group
- * 	(2)  Clears the tty from being controlling the session
- * 	(3)  Clears the controlling tty for all processes in the
- * 		session group.
- *
- *	The argument on_exit is set to 1 if called when a process is
- *	exiting; it is 0 if called by the ioctl TIOCNOTTY.
- *
- *	Locking:
- *		BTM is taken for hysterical raisins, and held when
- *		  called from no_tty().
- *		  tty_mutex is taken to protect tty
- *		  ->siglock is taken to protect ->signal/->sighand
- *		  tasklist_lock is taken to walk process list for sessions
- *		    ->siglock is taken to protect ->signal/->sighand
- */
-
-void disassociate_ctty(int on_exit)
-{
-	struct tty_struct *tty;
-	struct pid *tty_pgrp = NULL;
-
-	if (!current->signal->leader)
-		return;
-
-	tty = get_current_tty();
-	if (tty) {
-		tty_pgrp = get_pid(tty->pgrp);
-		if (on_exit) {
-			if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
-				tty_vhangup(tty);
-		}
-		tty_kref_put(tty);
-	} else if (on_exit) {
-		struct pid *old_pgrp;
-		spin_lock_irq(&current->sighand->siglock);
-		old_pgrp = current->signal->tty_old_pgrp;
-		current->signal->tty_old_pgrp = NULL;
-		spin_unlock_irq(&current->sighand->siglock);
-		if (old_pgrp) {
-			kill_pgrp(old_pgrp, SIGHUP, on_exit);
-			kill_pgrp(old_pgrp, SIGCONT, on_exit);
-			put_pid(old_pgrp);
-		}
-		return;
-	}
-	if (tty_pgrp) {
-		kill_pgrp(tty_pgrp, SIGHUP, on_exit);
-		if (!on_exit)
-			kill_pgrp(tty_pgrp, SIGCONT, on_exit);
-		put_pid(tty_pgrp);
-	}
-
-	spin_lock_irq(&current->sighand->siglock);
-	put_pid(current->signal->tty_old_pgrp);
-	current->signal->tty_old_pgrp = NULL;
-	spin_unlock_irq(&current->sighand->siglock);
-
-	tty = get_current_tty();
-	if (tty) {
-		unsigned long flags;
-		spin_lock_irqsave(&tty->ctrl_lock, flags);
-		put_pid(tty->session);
-		put_pid(tty->pgrp);
-		tty->session = NULL;
-		tty->pgrp = NULL;
-		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-		tty_kref_put(tty);
-	} else {
-#ifdef TTY_DEBUG_HANGUP
-		printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
-		       " = NULL", tty);
-#endif
-	}
-
-	/* Now clear signal->tty under the lock */
-	read_lock(&tasklist_lock);
-	session_clear_tty(task_session(current));
-	read_unlock(&tasklist_lock);
-}
-
-/**
- *
- *	no_tty	- Ensure the current process does not have a controlling tty
- */
-void no_tty(void)
-{
-	struct task_struct *tsk = current;
-	tty_lock();
-	disassociate_ctty(0);
-	tty_unlock();
-	proc_clear_tty(tsk);
-}
-
-
-/**
- *	stop_tty	-	propagate flow control
- *	@tty: tty to stop
- *
- *	Perform flow control to the driver. For PTY/TTY pairs we
- *	must also propagate the TIOCKPKT status. May be called
- *	on an already stopped device and will not re-call the driver
- *	method.
- *
- *	This functionality is used by both the line disciplines for
- *	halting incoming flow and by the driver. It may therefore be
- *	called from any context, may be under the tty atomic_write_lock
- *	but not always.
- *
- *	Locking:
- *		Uses the tty control lock internally
- */
-
-void stop_tty(struct tty_struct *tty)
-{
-	unsigned long flags;
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	if (tty->stopped) {
-		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-		return;
-	}
-	tty->stopped = 1;
-	if (tty->link && tty->link->packet) {
-		tty->ctrl_status &= ~TIOCPKT_START;
-		tty->ctrl_status |= TIOCPKT_STOP;
-		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-	if (tty->ops->stop)
-		(tty->ops->stop)(tty);
-}
-
-EXPORT_SYMBOL(stop_tty);
-
-/**
- *	start_tty	-	propagate flow control
- *	@tty: tty to start
- *
- *	Start a tty that has been stopped if at all possible. Perform
- *	any necessary wakeups and propagate the TIOCPKT status. If this
- *	is the tty was previous stopped and is being started then the
- *	driver start method is invoked and the line discipline woken.
- *
- *	Locking:
- *		ctrl_lock
- */
-
-void start_tty(struct tty_struct *tty)
-{
-	unsigned long flags;
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	if (!tty->stopped || tty->flow_stopped) {
-		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-		return;
-	}
-	tty->stopped = 0;
-	if (tty->link && tty->link->packet) {
-		tty->ctrl_status &= ~TIOCPKT_STOP;
-		tty->ctrl_status |= TIOCPKT_START;
-		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
-	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-	if (tty->ops->start)
-		(tty->ops->start)(tty);
-	/* If we have a running line discipline it may need kicking */
-	tty_wakeup(tty);
-}
-
-EXPORT_SYMBOL(start_tty);
-
-/**
- *	tty_read	-	read method for tty device files
- *	@file: pointer to tty file
- *	@buf: user buffer
- *	@count: size of user buffer
- *	@ppos: unused
- *
- *	Perform the read system call function on this terminal device. Checks
- *	for hung up devices before calling the line discipline method.
- *
- *	Locking:
- *		Locks the line discipline internally while needed. Multiple
- *	read calls may be outstanding in parallel.
- */
-
-static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
-			loff_t *ppos)
-{
-	int i;
-	struct inode *inode = file->f_path.dentry->d_inode;
-	struct tty_struct *tty = file_tty(file);
-	struct tty_ldisc *ld;
-
-	if (tty_paranoia_check(tty, inode, "tty_read"))
-		return -EIO;
-	if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
-		return -EIO;
-
-	/* We want to wait for the line discipline to sort out in this
-	   situation */
-	ld = tty_ldisc_ref_wait(tty);
-	if (ld->ops->read)
-		i = (ld->ops->read)(tty, file, buf, count);
-	else
-		i = -EIO;
-	tty_ldisc_deref(ld);
-	if (i > 0)
-		inode->i_atime = current_fs_time(inode->i_sb);
-	return i;
-}
-
-void tty_write_unlock(struct tty_struct *tty)
-{
-	mutex_unlock(&tty->atomic_write_lock);
-	wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
-}
-
-int tty_write_lock(struct tty_struct *tty, int ndelay)
-{
-	if (!mutex_trylock(&tty->atomic_write_lock)) {
-		if (ndelay)
-			return -EAGAIN;
-		if (mutex_lock_interruptible(&tty->atomic_write_lock))
-			return -ERESTARTSYS;
-	}
-	return 0;
-}
-
-/*
- * Split writes up in sane blocksizes to avoid
- * denial-of-service type attacks
- */
-static inline ssize_t do_tty_write(
-	ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
-	struct tty_struct *tty,
-	struct file *file,
-	const char __user *buf,
-	size_t count)
-{
-	ssize_t ret, written = 0;
-	unsigned int chunk;
-
-	ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
-	if (ret < 0)
-		return ret;
-
-	/*
-	 * We chunk up writes into a temporary buffer. This
-	 * simplifies low-level drivers immensely, since they
-	 * don't have locking issues and user mode accesses.
-	 *
-	 * But if TTY_NO_WRITE_SPLIT is set, we should use a
-	 * big chunk-size..
-	 *
-	 * The default chunk-size is 2kB, because the NTTY
-	 * layer has problems with bigger chunks. It will
-	 * claim to be able to handle more characters than
-	 * it actually does.
-	 *
-	 * FIXME: This can probably go away now except that 64K chunks
-	 * are too likely to fail unless switched to vmalloc...
-	 */
-	chunk = 2048;
-	if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
-		chunk = 65536;
-	if (count < chunk)
-		chunk = count;
-
-	/* write_buf/write_cnt is protected by the atomic_write_lock mutex */
-	if (tty->write_cnt < chunk) {
-		unsigned char *buf_chunk;
-
-		if (chunk < 1024)
-			chunk = 1024;
-
-		buf_chunk = kmalloc(chunk, GFP_KERNEL);
-		if (!buf_chunk) {
-			ret = -ENOMEM;
-			goto out;
-		}
-		kfree(tty->write_buf);
-		tty->write_cnt = chunk;
-		tty->write_buf = buf_chunk;
-	}
-
-	/* Do the write .. */
-	for (;;) {
-		size_t size = count;
-		if (size > chunk)
-			size = chunk;
-		ret = -EFAULT;
-		if (copy_from_user(tty->write_buf, buf, size))
-			break;
-		ret = write(tty, file, tty->write_buf, size);
-		if (ret <= 0)
-			break;
-		written += ret;
-		buf += ret;
-		count -= ret;
-		if (!count)
-			break;
-		ret = -ERESTARTSYS;
-		if (signal_pending(current))
-			break;
-		cond_resched();
-	}
-	if (written) {
-		struct inode *inode = file->f_path.dentry->d_inode;
-		inode->i_mtime = current_fs_time(inode->i_sb);
-		ret = written;
-	}
-out:
-	tty_write_unlock(tty);
-	return ret;
-}
-
-/**
- * tty_write_message - write a message to a certain tty, not just the console.
- * @tty: the destination tty_struct
- * @msg: the message to write
- *
- * This is used for messages that need to be redirected to a specific tty.
- * We don't put it into the syslog queue right now maybe in the future if
- * really needed.
- *
- * We must still hold the BTM and test the CLOSING flag for the moment.
- */
-
-void tty_write_message(struct tty_struct *tty, char *msg)
-{
-	if (tty) {
-		mutex_lock(&tty->atomic_write_lock);
-		tty_lock();
-		if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
-			tty_unlock();
-			tty->ops->write(tty, msg, strlen(msg));
-		} else
-			tty_unlock();
-		tty_write_unlock(tty);
-	}
-	return;
-}
-
-
-/**
- *	tty_write		-	write method for tty device file
- *	@file: tty file pointer
- *	@buf: user data to write
- *	@count: bytes to write
- *	@ppos: unused
- *
- *	Write data to a tty device via the line discipline.
- *
- *	Locking:
- *		Locks the line discipline as required
- *		Writes to the tty driver are serialized by the atomic_write_lock
- *	and are then processed in chunks to the device. The line discipline
- *	write method will not be invoked in parallel for each device.
- */
-
-static ssize_t tty_write(struct file *file, const char __user *buf,
-						size_t count, loff_t *ppos)
-{
-	struct inode *inode = file->f_path.dentry->d_inode;
-	struct tty_struct *tty = file_tty(file);
- 	struct tty_ldisc *ld;
-	ssize_t ret;
-
-	if (tty_paranoia_check(tty, inode, "tty_write"))
-		return -EIO;
-	if (!tty || !tty->ops->write ||
-		(test_bit(TTY_IO_ERROR, &tty->flags)))
-			return -EIO;
-	/* Short term debug to catch buggy drivers */
-	if (tty->ops->write_room == NULL)
-		printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
-			tty->driver->name);
-	ld = tty_ldisc_ref_wait(tty);
-	if (!ld->ops->write)
-		ret = -EIO;
-	else
-		ret = do_tty_write(ld->ops->write, tty, file, buf, count);
-	tty_ldisc_deref(ld);
-	return ret;
-}
-
-ssize_t redirected_tty_write(struct file *file, const char __user *buf,
-						size_t count, loff_t *ppos)
-{
-	struct file *p = NULL;
-
-	spin_lock(&redirect_lock);
-	if (redirect) {
-		get_file(redirect);
-		p = redirect;
-	}
-	spin_unlock(&redirect_lock);
-
-	if (p) {
-		ssize_t res;
-		res = vfs_write(p, buf, count, &p->f_pos);
-		fput(p);
-		return res;
-	}
-	return tty_write(file, buf, count, ppos);
-}
-
-static char ptychar[] = "pqrstuvwxyzabcde";
-
-/**
- *	pty_line_name	-	generate name for a pty
- *	@driver: the tty driver in use
- *	@index: the minor number
- *	@p: output buffer of at least 6 bytes
- *
- *	Generate a name from a driver reference and write it to the output
- *	buffer.
- *
- *	Locking: None
- */
-static void pty_line_name(struct tty_driver *driver, int index, char *p)
-{
-	int i = index + driver->n