tty_io.c 76.7 KB
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/*
 *  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
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 * makes for cleaner and more compact code.  -TYT, 9/17/92
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 *
 * 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
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 *
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 * 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
 *
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 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
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 *	-- 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.
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 * alloc_tty_struct() always uses kmalloc()
 *			 -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
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 */

#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>
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#include <linux/fdtable.h>
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#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>
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#include <linux/delay.h>
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#include <linux/seq_file.h>
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#include <linux/uaccess.h>
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#include <asm/system.h>

#include <linux/kbd_kern.h>
#include <linux/vt_kern.h>
#include <linux/selection.h>

#include <linux/kmod.h>
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#include <linux/nsproxy.h>
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#undef TTY_DEBUG_HANGUP

#define TTY_PARANOIA_CHECK 1
#define CHECK_TTY_COUNT 1

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struct ktermios tty_std_termios = {	/* for the benefit of tty drivers  */
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	.c_iflag = ICRNL | IXON,
	.c_oflag = OPOST | ONLCR,
	.c_cflag = B38400 | CS8 | CREAD | HUPCL,
	.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
		   ECHOCTL | ECHOKE | IEXTEN,
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	.c_cc = INIT_C_CC,
	.c_ispeed = 38400,
	.c_ospeed = 38400
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};

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 */
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LIST_HEAD(tty_drivers);			/* linked list of tty drivers */

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/* Mutex to protect creating and releasing a tty. This is shared with
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   vt.c for deeply disgusting hack reasons */
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DEFINE_MUTEX(tty_mutex);
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EXPORT_SYMBOL(tty_mutex);
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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 *);
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ssize_t redirected_tty_write(struct file *, const char __user *,
							size_t, loff_t *);
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static unsigned int tty_poll(struct file *, poll_table *);
static int tty_open(struct inode *, struct file *);
static int tty_release(struct inode *, struct file *);
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long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
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#ifdef CONFIG_COMPAT
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static long tty_compat_ioctl(struct file *file, unsigned int cmd,
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				unsigned long arg);
#else
#define tty_compat_ioctl NULL
#endif
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static int tty_fasync(int fd, struct file *filp, int on);
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static void release_tty(struct tty_struct *tty, int idx);
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static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
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static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
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/**
 *	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
 */
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struct tty_struct *alloc_tty_struct(void)
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{
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	return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
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}

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/**
 *	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
 */

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void free_tty_struct(struct tty_struct *tty)
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{
	kfree(tty->write_buf);
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	tty_buffer_free_all(tty);
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	kfree(tty);
}

#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)

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/**
 *	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
 */

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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);

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int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
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			      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;
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	file_list_lock();
	list_for_each(p, &tty->tty_files) {
		count++;
	}
	file_list_unlock();
	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;
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	}
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#endif
	return 0;
}

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/**
 *	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
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 */
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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;
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		return tty_driver_kref_get(p);
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	}
	return NULL;
}

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#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;
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	int len;
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	char *str, *stp;
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	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);

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	mutex_lock(&tty_mutex);
	/* Search through the tty devices to look for a match */
	list_for_each_entry(p, &tty_drivers, tty_drivers) {
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		if (strncmp(name, p->name, len) != 0)
			continue;
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		stp = str;
		if (*stp == ',')
			stp++;
		if (*stp == '\0')
			stp = NULL;
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		if (tty_line >= 0 && tty_line <= p->num && p->ops &&
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		    p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
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			res = tty_driver_kref_get(p);
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			*line = tty_line;
			break;
		}
	}
	mutex_unlock(&tty_mutex);

	return res;
}
EXPORT_SYMBOL_GPL(tty_find_polling_driver);
#endif

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/**
 *	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)
 *
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 *	Locking: ctrl_lock
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 */
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int tty_check_change(struct tty_struct *tty)
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{
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	unsigned long flags;
	int ret = 0;

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	if (current->signal->tty != tty)
		return 0;
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	spin_lock_irqsave(&tty->ctrl_lock, flags);

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	if (!tty->pgrp) {
		printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
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		goto out_unlock;
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	}
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	if (task_pgrp(current) == tty->pgrp)
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		goto out_unlock;
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
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	if (is_ignored(SIGTTOU))
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		goto out;
	if (is_current_pgrp_orphaned()) {
		ret = -EIO;
		goto out;
	}
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	kill_pgrp(task_pgrp(current), SIGTTOU, 1);
	set_thread_flag(TIF_SIGPENDING);
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	ret = -ERESTARTSYS;
out:
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	return ret;
out_unlock:
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	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
	return ret;
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}

EXPORT_SYMBOL(tty_check_change);

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static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
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				size_t count, loff_t *ppos)
{
	return 0;
}

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static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
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				 size_t count, loff_t *ppos)
{
	return -EIO;
}

/* No kernel lock held - none needed ;) */
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static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
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{
	return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
}

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static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
		unsigned long arg)
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{
	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
}

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static long hung_up_tty_compat_ioctl(struct file *file,
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				     unsigned int cmd, unsigned long arg)
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{
	return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
}

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static const struct file_operations tty_fops = {
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	.llseek		= no_llseek,
	.read		= tty_read,
	.write		= tty_write,
	.poll		= tty_poll,
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	.unlocked_ioctl	= tty_ioctl,
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	.compat_ioctl	= tty_compat_ioctl,
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	.open		= tty_open,
	.release	= tty_release,
	.fasync		= tty_fasync,
};

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static const struct file_operations console_fops = {
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	.llseek		= no_llseek,
	.read		= tty_read,
	.write		= redirected_tty_write,
	.poll		= tty_poll,
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	.unlocked_ioctl	= tty_ioctl,
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	.compat_ioctl	= tty_compat_ioctl,
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	.open		= tty_open,
	.release	= tty_release,
	.fasync		= tty_fasync,
};

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static const struct file_operations hung_up_tty_fops = {
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	.llseek		= no_llseek,
	.read		= hung_up_tty_read,
	.write		= hung_up_tty_write,
	.poll		= hung_up_tty_poll,
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	.unlocked_ioctl	= hung_up_tty_ioctl,
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	.compat_ioctl	= hung_up_tty_compat_ioctl,
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	.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.
 */
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void tty_wakeup(struct tty_struct *tty)
{
	struct tty_ldisc *ld;
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	if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
		ld = tty_ldisc_ref(tty);
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		if (ld) {
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			if (ld->ops->write_wakeup)
				ld->ops->write_wakeup(tty);
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			tty_ldisc_deref(ld);
		}
	}
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	wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
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}

EXPORT_SYMBOL_GPL(tty_wakeup);

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/**
 *	do_tty_hangup		-	actual handler for hangup events
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 *	@work: tty device
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 *
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 *	This can be called by the "eventd" kernel thread.  That is process
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 *	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:
 *		BKL
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 *		  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
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 */
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static void do_tty_hangup(struct work_struct *work)
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{
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	struct tty_struct *tty =
		container_of(work, struct tty_struct, hangup_work);
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	struct file *cons_filp = NULL;
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	struct file *filp, *f = NULL;
	struct task_struct *p;
	int    closecount = 0, n;
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	unsigned long flags;
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	int refs = 0;
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	if (!tty)
		return;

	/* inuse_filps is protected by the single kernel lock */
	lock_kernel();

	spin_lock(&redirect_lock);
	if (redirect && redirect->private_data == tty) {
		f = redirect;
		redirect = NULL;
	}
	spin_unlock(&redirect_lock);
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	check_tty_count(tty, "do_tty_hangup");
	file_list_lock();
	/* This breaks for file handles being sent over AF_UNIX sockets ? */
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	list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
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		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;
	}
	file_list_unlock();
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	tty_ldisc_hangup(tty);
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	read_lock(&tasklist_lock);
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	if (tty->session) {
		do_each_pid_task(tty->session, PIDTYPE_SID, p) {
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			spin_lock_irq(&p->sighand->siglock);
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			if (p->signal->tty == tty) {
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				p->signal->tty = NULL;
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				/* We defer the dereferences outside fo
				   the tasklist lock */
				refs++;
			}
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			if (!p->signal->leader) {
				spin_unlock_irq(&p->sighand->siglock);
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				continue;
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			}
			__group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
			__group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
551
			put_pid(p->signal->tty_old_pgrp);  /* A noop */
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552
			spin_lock_irqsave(&tty->ctrl_lock, flags);
553 554
			if (tty->pgrp)
				p->signal->tty_old_pgrp = get_pid(tty->pgrp);
A
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555
			spin_unlock_irqrestore(&tty->ctrl_lock, flags);
556
			spin_unlock_irq(&p->sighand->siglock);
557
		} while_each_pid_task(tty->session, PIDTYPE_SID, p);
L
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558 559 560
	}
	read_unlock(&tasklist_lock);

A
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561
	spin_lock_irqsave(&tty->ctrl_lock, flags);
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562 563 564
	clear_bit(TTY_THROTTLED, &tty->flags);
	clear_bit(TTY_PUSH, &tty->flags);
	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
565 566
	put_pid(tty->session);
	put_pid(tty->pgrp);
567 568
	tty->session = NULL;
	tty->pgrp = NULL;
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569
	tty->ctrl_status = 0;
A
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570
	set_bit(TTY_HUPPED, &tty->flags);
A
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571 572
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);

A
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573 574 575 576
	/* Account for the p->signal references we killed */
	while (refs--)
		tty_kref_put(tty);

L
Linus Torvalds 已提交
577
	/*
578 579 580 581
	 * 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.
L
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582 583
	 */
	if (cons_filp) {
A
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584
		if (tty->ops->close)
L
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585
			for (n = 0; n < closecount; n++)
A
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586 587 588
				tty->ops->close(tty, cons_filp);
	} else if (tty->ops->hangup)
		(tty->ops->hangup)(tty);
589 590 591 592 593 594
	/*
	 * 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.
	 */
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595
	set_bit(TTY_HUPPED, &tty->flags);
A
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596
	tty_ldisc_enable(tty);
L
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597 598 599 600 601
	unlock_kernel();
	if (f)
		fput(f);
}

602 603 604 605 606 607 608 609
/**
 *	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.
 */

610
void tty_hangup(struct tty_struct *tty)
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{
#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);

621 622 623 624 625 626
/**
 *	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
627
 *	is complete. That guarantee is necessary for security reasons.
628 629
 */

630
void tty_vhangup(struct tty_struct *tty)
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631 632 633 634 635 636
{
#ifdef TTY_DEBUG_HANGUP
	char	buf[64];

	printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
#endif
637
	do_tty_hangup(&tty->hangup_work);
L
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638
}
639

L
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640 641
EXPORT_SYMBOL(tty_vhangup);

A
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642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658
/**
 *	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);
	}
}

659 660 661 662 663 664 665 666
/**
 *	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
 */

667
int tty_hung_up_p(struct file *filp)
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668 669 670 671 672 673
{
	return (filp->f_op == &hung_up_tty_fops);
}

EXPORT_SYMBOL(tty_hung_up_p);

674
static void session_clear_tty(struct pid *session)
675 676
{
	struct task_struct *p;
677
	do_each_pid_task(session, PIDTYPE_SID, p) {
678
		proc_clear_tty(p);
679
	} while_each_pid_task(session, PIDTYPE_SID, p);
680 681
}

682 683 684
/**
 *	disassociate_ctty	-	disconnect controlling tty
 *	@on_exit: true if exiting so need to "hang up" the session
L
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685
 *
686 687 688 689
 *	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:
L
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690 691 692 693 694
 * 	(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.
 *
695 696 697
 *	The argument on_exit is set to 1 if called when a process is
 *	exiting; it is 0 if called by the ioctl TIOCNOTTY.
 *
698
 *	Locking:
699
 *		BKL is taken for hysterical raisins
700 701 702 703
 *		  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
L
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704
 */
705

L
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706 707 708
void disassociate_ctty(int on_exit)
{
	struct tty_struct *tty;
709
	struct pid *tty_pgrp = NULL;
L
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710 711


712
	tty = get_current_tty();
L
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713
	if (tty) {
714
		tty_pgrp = get_pid(tty->pgrp);
A
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715
		lock_kernel();
L
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716 717
		if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
			tty_vhangup(tty);
A
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718
		unlock_kernel();
A
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719
		tty_kref_put(tty);
720
	} else if (on_exit) {
721
		struct pid *old_pgrp;
722 723
		spin_lock_irq(&current->sighand->siglock);
		old_pgrp = current->signal->tty_old_pgrp;
724
		current->signal->tty_old_pgrp = NULL;
725
		spin_unlock_irq(&current->sighand->siglock);
726
		if (old_pgrp) {
727 728 729
			kill_pgrp(old_pgrp, SIGHUP, on_exit);
			kill_pgrp(old_pgrp, SIGCONT, on_exit);
			put_pid(old_pgrp);
L
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730 731 732
		}
		return;
	}
733 734
	if (tty_pgrp) {
		kill_pgrp(tty_pgrp, SIGHUP, on_exit);
L
Linus Torvalds 已提交
735
		if (!on_exit)
736 737
			kill_pgrp(tty_pgrp, SIGCONT, on_exit);
		put_pid(tty_pgrp);
L
Linus Torvalds 已提交
738 739
	}

740
	spin_lock_irq(&current->sighand->siglock);
741
	put_pid(current->signal->tty_old_pgrp);
R
Randy Dunlap 已提交
742
	current->signal->tty_old_pgrp = NULL;
743 744 745 746
	spin_unlock_irq(&current->sighand->siglock);

	tty = get_current_tty();
	if (tty) {
A
Alan Cox 已提交
747 748
		unsigned long flags;
		spin_lock_irqsave(&tty->ctrl_lock, flags);
749 750 751 752
		put_pid(tty->session);
		put_pid(tty->pgrp);
		tty->session = NULL;
		tty->pgrp = NULL;
A
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753
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
A
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754
		tty_kref_put(tty);
755 756 757 758 759 760
	} else {
#ifdef TTY_DEBUG_HANGUP
		printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
		       " = NULL", tty);
#endif
	}
L
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761 762 763

	/* Now clear signal->tty under the lock */
	read_lock(&tasklist_lock);
764
	session_clear_tty(task_session(current));
L
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765 766 767
	read_unlock(&tasklist_lock);
}

768 769 770 771 772 773 774
/**
 *
 *	no_tty	- Ensure the current process does not have a controlling tty
 */
void no_tty(void)
{
	struct task_struct *tsk = current;
A
Alan Cox 已提交
775
	lock_kernel();
776 777
	if (tsk->signal->leader)
		disassociate_ctty(0);
A
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778
	unlock_kernel();
779 780 781
	proc_clear_tty(tsk);
}

782 783

/**
784
 *	stop_tty	-	propagate flow control
785 786 787
 *	@tty: tty to stop
 *
 *	Perform flow control to the driver. For PTY/TTY pairs we
788
 *	must also propagate the TIOCKPKT status. May be called
789 790 791 792 793 794 795 796 797
 *	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:
A
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798
 *		Uses the tty control lock internally
799 800
 */

L
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801 802
void stop_tty(struct tty_struct *tty)
{
A
Alan Cox 已提交
803 804 805 806
	unsigned long flags;
	spin_lock_irqsave(&tty->ctrl_lock, flags);
	if (tty->stopped) {
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
L
Linus Torvalds 已提交
807
		return;
A
Alan Cox 已提交
808
	}
L
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809 810 811 812
	tty->stopped = 1;
	if (tty->link && tty->link->packet) {
		tty->ctrl_status &= ~TIOCPKT_START;
		tty->ctrl_status |= TIOCPKT_STOP;
813
		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
L
Linus Torvalds 已提交
814
	}
A
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815
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
A
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816 817
	if (tty->ops->stop)
		(tty->ops->stop)(tty);
L
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818 819 820 821
}

EXPORT_SYMBOL(stop_tty);

822
/**
823
 *	start_tty	-	propagate flow control
824 825 826
 *	@tty: tty to start
 *
 *	Start a tty that has been stopped if at all possible. Perform
827
 *	any necessary wakeups and propagate the TIOCPKT status. If this
828 829 830 831
 *	is the tty was previous stopped and is being started then the
 *	driver start method is invoked and the line discipline woken.
 *
 *	Locking:
A
Alan Cox 已提交
832
 *		ctrl_lock
833 834
 */

L
Linus Torvalds 已提交
835 836
void start_tty(struct tty_struct *tty)
{
A
Alan Cox 已提交
837 838 839 840
	unsigned long flags;
	spin_lock_irqsave(&tty->ctrl_lock, flags);
	if (!tty->stopped || tty->flow_stopped) {
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
L
Linus Torvalds 已提交
841
		return;
A
Alan Cox 已提交
842
	}
L
Linus Torvalds 已提交
843 844 845 846
	tty->stopped = 0;
	if (tty->link && tty->link->packet) {
		tty->ctrl_status &= ~TIOCPKT_STOP;
		tty->ctrl_status |= TIOCPKT_START;
847
		wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
L
Linus Torvalds 已提交
848
	}
A
Alan Cox 已提交
849
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
A
Alan Cox 已提交
850 851
	if (tty->ops->start)
		(tty->ops->start)(tty);
L
Linus Torvalds 已提交
852 853 854 855 856 857
	/* If we have a running line discipline it may need kicking */
	tty_wakeup(tty);
}

EXPORT_SYMBOL(start_tty);

858 859 860 861 862 863 864 865 866 867 868
/**
 *	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:
A
Alan Cox 已提交
869 870
 *		Locks the line discipline internally while needed. Multiple
 *	read calls may be outstanding in parallel.
871 872
 */

873
static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
L
Linus Torvalds 已提交
874 875 876
			loff_t *ppos)
{
	int i;
877
	struct tty_struct *tty;
L
Linus Torvalds 已提交
878 879 880 881
	struct inode *inode;
	struct tty_ldisc *ld;

	tty = (struct tty_struct *)file->private_data;
882
	inode = file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
883 884 885 886 887 888 889 890
	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);
A
Alan Cox 已提交
891 892
	if (ld->ops->read)
		i = (ld->ops->read)(tty, file, buf, count);
L
Linus Torvalds 已提交
893 894 895 896 897 898 899 900
	else
		i = -EIO;
	tty_ldisc_deref(ld);
	if (i > 0)
		inode->i_atime = current_fs_time(inode->i_sb);
	return i;
}

901 902 903
void tty_write_unlock(struct tty_struct *tty)
{
	mutex_unlock(&tty->atomic_write_lock);
904
	wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
905 906 907 908 909 910 911 912 913 914 915 916 917
}

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;
}

L
Linus Torvalds 已提交
918 919 920 921 922 923 924 925 926 927 928
/*
 * 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)
{
929
	ssize_t ret, written = 0;
L
Linus Torvalds 已提交
930
	unsigned int chunk;
931

932 933 934
	ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
	if (ret < 0)
		return ret;
L
Linus Torvalds 已提交
935 936 937 938 939 940 941 942 943 944 945 946 947

	/*
	 * 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.
948 949 950
	 *
	 * FIXME: This can probably go away now except that 64K chunks
	 * are too likely to fail unless switched to vmalloc...
L
Linus Torvalds 已提交
951 952 953 954 955 956 957
	 */
	chunk = 2048;
	if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
		chunk = 65536;
	if (count < chunk)
		chunk = count;

I
Ingo Molnar 已提交
958
	/* write_buf/write_cnt is protected by the atomic_write_lock mutex */
L
Linus Torvalds 已提交
959
	if (tty->write_cnt < chunk) {
J
Jason Wessel 已提交
960
		unsigned char *buf_chunk;
L
Linus Torvalds 已提交
961 962 963 964

		if (chunk < 1024)
			chunk = 1024;

J
Jason Wessel 已提交
965 966
		buf_chunk = kmalloc(chunk, GFP_KERNEL);
		if (!buf_chunk) {
967 968
			ret = -ENOMEM;
			goto out;
L
Linus Torvalds 已提交
969 970 971
		}
		kfree(tty->write_buf);
		tty->write_cnt = chunk;
J
Jason Wessel 已提交
972
		tty->write_buf = buf_chunk;
L
Linus Torvalds 已提交
973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996
	}

	/* 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) {
997
		struct inode *inode = file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
998 999 1000
		inode->i_mtime = current_fs_time(inode->i_sb);
		ret = written;
	}
1001 1002
out:
	tty_write_unlock(tty);
L
Linus Torvalds 已提交
1003 1004 1005
	return ret;
}

1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
/**
 * 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 BKL and test the CLOSING flag for the moment.
 */

void tty_write_message(struct tty_struct *tty, char *msg)
{
	lock_kernel();
	if (tty) {
		mutex_lock(&tty->atomic_write_lock);
		if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
			tty->ops->write(tty, msg, strlen(msg));
		tty_write_unlock(tty);
	}
	unlock_kernel();
	return;
}

L
Linus Torvalds 已提交
1031

1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044
/**
 *	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
1045
 *	write method will not be invoked in parallel for each device.
1046 1047
 */

1048 1049
static ssize_t tty_write(struct file *file, const char __user *buf,
						size_t count, loff_t *ppos)
L
Linus Torvalds 已提交
1050
{
1051
	struct tty_struct *tty;
1052
	struct inode *inode = file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
1053 1054
	ssize_t ret;
	struct tty_ldisc *ld;
1055

L
Linus Torvalds 已提交
1056 1057 1058
	tty = (struct tty_struct *)file->private_data;
	if (tty_paranoia_check(tty, inode, "tty_write"))
		return -EIO;
A
Alan Cox 已提交
1059
	if (!tty || !tty->ops->write ||
1060 1061
		(test_bit(TTY_IO_ERROR, &tty->flags)))
			return -EIO;
A
Alan Cox 已提交
1062 1063 1064 1065
	/* 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);
1066
	ld = tty_ldisc_ref_wait(tty);
A
Alan Cox 已提交
1067
	if (!ld->ops->write)
L
Linus Torvalds 已提交
1068 1069
		ret = -EIO;
	else
A
Alan Cox 已提交
1070
		ret = do_tty_write(ld->ops->write, tty, file, buf, count);
L
Linus Torvalds 已提交
1071 1072 1073 1074
	tty_ldisc_deref(ld);
	return ret;
}

1075 1076
ssize_t redirected_tty_write(struct file *file, const char __user *buf,
						size_t count, loff_t *ppos)
L
Linus Torvalds 已提交
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
{
	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";

1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109
/**
 *	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)
L
Linus Torvalds 已提交
1110 1111 1112 1113
{
	int i = index + driver->name_base;
	/* ->name is initialized to "ttyp", but "tty" is expected */
	sprintf(p, "%s%c%x",
1114 1115
		driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
		ptychar[i >> 4 & 0xf], i & 0xf);
L
Linus Torvalds 已提交
1116 1117
}

1118
/**
A
Alan Cox 已提交
1119
 *	tty_line_name	-	generate name for a tty
1120 1121 1122 1123 1124 1125 1126 1127 1128 1129
 *	@driver: the tty driver in use
 *	@index: the minor number
 *	@p: output buffer of at least 7 bytes
 *
 *	Generate a name from a driver reference and write it to the output
 *	buffer.
 *
 *	Locking: None
 */
static void tty_line_name(struct tty_driver *driver, int index, char *p)
L
Linus Torvalds 已提交
1130 1131 1132 1133
{
	sprintf(p, "%s%d", driver->name, index + driver->name_base);
}

1134 1135 1136 1137
/**
 *	tty_driver_lookup_tty() - find an existing tty, if any
 *	@driver: the driver for the tty
 *	@idx:	 the minor number
1138
 *
1139
 *	Return the tty, if found or ERR_PTR() otherwise.
1140
 *
1141 1142 1143
 *	Locking: tty_mutex must be held. If tty is found, the mutex must
 *	be held until the 'fast-open' is also done. Will change once we
 *	have refcounting in the driver and per driver locking
1144
 */
1145
static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1146
		struct inode *inode, int idx)
1147 1148 1149
{
	struct tty_struct *tty;

1150
	if (driver->ops->lookup)
1151
		return driver->ops->lookup(driver, inode, idx);
1152

A
Alan Cox 已提交
1153
	tty = driver->ttys[idx];
1154 1155 1156
	return tty;
}

1157 1158 1159 1160 1161 1162 1163 1164 1165 1166
/**
 *	tty_init_termios	-  helper for termios setup
 *	@tty: the tty to set up
 *
 *	Initialise the termios structures for this tty. Thus runs under
 *	the tty_mutex currently so we can be relaxed about ordering.
 */

int tty_init_termios(struct tty_struct *tty)
{
A
Alan Cox 已提交
1167
	struct ktermios *tp;
1168 1169 1170 1171
	int idx = tty->index;

	tp = tty->driver->termios[idx];
	if (tp == NULL) {
A
Alan Cox 已提交
1172 1173
		tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
		if (tp == NULL)
1174 1175 1176 1177 1178 1179
			return -ENOMEM;
		memcpy(tp, &tty->driver->init_termios,
						sizeof(struct ktermios));
		tty->driver->termios[idx] = tp;
	}
	tty->termios = tp;
A
Alan Cox 已提交
1180
	tty->termios_locked = tp + 1;
1181 1182 1183 1184 1185 1186 1187

	/* Compatibility until drivers always set this */
	tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
	tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
	return 0;
}

1188
/**
A
Alan Cox 已提交
1189 1190 1191 1192 1193
 *	tty_driver_install_tty() - install a tty entry in the driver
 *	@driver: the driver for the tty
 *	@tty: the tty
 *
 *	Install a tty object into the driver tables. The tty->index field
1194 1195 1196
 *	will be set by the time this is called. This method is responsible
 *	for ensuring any need additional structures are allocated and
 *	configured.
A
Alan Cox 已提交
1197 1198 1199 1200 1201 1202
 *
 *	Locking: tty_mutex for now
 */
static int tty_driver_install_tty(struct tty_driver *driver,
						struct tty_struct *tty)
{
1203 1204
	int idx = tty->index;

A
Alan Cox 已提交
1205 1206
	if (driver->ops->install)
		return driver->ops->install(driver, tty);
1207 1208 1209 1210 1211 1212 1213 1214

	if (tty_init_termios(tty) == 0) {
		tty_driver_kref_get(driver);
		tty->count++;
		driver->ttys[idx] = tty;
		return 0;
	}
	return -ENOMEM;
A
Alan Cox 已提交
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
}

/**
 *	tty_driver_remove_tty() - remove a tty from the driver tables
 *	@driver: the driver for the tty
 *	@idx:	 the minor number
 *
 *	Remvoe a tty object from the driver tables. The tty->index field
 *	will be set by the time this is called.
 *
 *	Locking: tty_mutex for now
 */
static void tty_driver_remove_tty(struct tty_driver *driver,
						struct tty_struct *tty)
{
	if (driver->ops->remove)
		driver->ops->remove(driver, tty);
	else
		driver->ttys[tty->index] = NULL;
}

/*
 * 	tty_reopen()	- fast re-open of an open tty
 * 	@tty	- the tty to open
1239
 *
1240
 *	Return 0 on success, -errno on error.
1241
 *
1242 1243
 *	Locking: tty_mutex must be held from the time the tty was found
 *		 till this open completes.
1244
 */
1245
static int tty_reopen(struct tty_struct *tty)
1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265
{
	struct tty_driver *driver = tty->driver;

	if (test_bit(TTY_CLOSING, &tty->flags))
		return -EIO;

	if (driver->type == TTY_DRIVER_TYPE_PTY &&
	    driver->subtype == PTY_TYPE_MASTER) {
		/*
		 * special case for PTY masters: only one open permitted,
		 * and the slave side open count is incremented as well.
		 */
		if (tty->count)
			return -EIO;

		tty->link->count++;
	}
	tty->count++;
	tty->driver = driver; /* N.B. why do this every time?? */

A
Alan Cox 已提交
1266
	mutex_lock(&tty->ldisc_mutex);
1267
	WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
A
Alan Cox 已提交
1268
	mutex_unlock(&tty->ldisc_mutex);
1269 1270 1271 1272

	return 0;
}

1273
/**
1274
 *	tty_init_dev		-	initialise a tty device
1275 1276
 *	@driver: tty driver we are opening a device on
 *	@idx: device index
1277 1278
 *	@ret_tty: returned tty structure
 *	@first_ok: ok to open a new device (used by ptmx)
1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
 *
 *	Prepare a tty device. This may not be a "new" clean device but
 *	could also be an active device. The pty drivers require special
 *	handling because of this.
 *
 *	Locking:
 *		The function is called under the tty_mutex, which
 *	protects us from the tty struct or driver itself going away.
 *
 *	On exit the tty device has the line discipline attached and
 *	a reference count of 1. If a pair was created for pty/tty use
 *	and the other was a pty master then it too has a reference count of 1.
 *
L
Linus Torvalds 已提交
1292
 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
I
Ingo Molnar 已提交
1293 1294
 * failed open.  The new code protects the open with a mutex, so it's
 * really quite straightforward.  The mutex locking can probably be
L
Linus Torvalds 已提交
1295 1296
 * relaxed for the (most common) case of reopening a tty.
 */
1297

1298 1299
struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
								int first_ok)
L
Linus Torvalds 已提交
1300
{
1301
	struct tty_struct *tty;
1302
	int retval;
L
Linus Torvalds 已提交
1303

1304
	/* Check if pty master is being opened multiple times */
1305
	if (driver->subtype == PTY_TYPE_MASTER &&
1306 1307 1308
		(driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
		return ERR_PTR(-EIO);

L
Linus Torvalds 已提交
1309 1310 1311 1312
	/*
	 * First time open is complex, especially for PTY devices.
	 * This code guarantees that either everything succeeds and the
	 * TTY is ready for operation, or else the table slots are vacated
1313
	 * and the allocated memory released.  (Except that the termios
L
Linus Torvalds 已提交
1314 1315 1316
	 * and locked termios may be retained.)
	 */

1317 1318
	if (!try_module_get(driver->owner))
		return ERR_PTR(-ENODEV);
L
Linus Torvalds 已提交
1319 1320

	tty = alloc_tty_struct();
1321
	if (!tty)
L
Linus Torvalds 已提交
1322
		goto fail_no_mem;
1323
	initialize_tty_struct(tty, driver, idx);
L
Linus Torvalds 已提交
1324

1325
	retval = tty_driver_install_tty(driver, tty);
1326 1327 1328 1329 1330
	if (retval < 0) {
		free_tty_struct(tty);
		module_put(driver->owner);
		return ERR_PTR(retval);
	}
A
Alan Cox 已提交
1331

1332
	/*
L
Linus Torvalds 已提交
1333
	 * Structures all installed ... call the ldisc open routines.
1334 1335
	 * If we fail here just call release_tty to clean up.  No need
	 * to decrement the use counts, as release_tty doesn't care.
L
Linus Torvalds 已提交
1336 1337
	 */

1338
	retval = tty_ldisc_setup(tty, tty->link);
1339 1340
	if (retval)
		goto release_mem_out;
1341
	return tty;
L
Linus Torvalds 已提交
1342 1343 1344

fail_no_mem:
	module_put(driver->owner);
1345
	return ERR_PTR(-ENOMEM);
L
Linus Torvalds 已提交
1346

1347
	/* call the tty release_tty routine to clean out this slot */
L
Linus Torvalds 已提交
1348
release_mem_out:
1349
	if (printk_ratelimit())
1350
		printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1351
				 "clearing slot %d\n", idx);
1352
	release_tty(tty, idx);
1353
	return ERR_PTR(retval);
L
Linus Torvalds 已提交
1354 1355
}

A
Alan Cox 已提交
1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
void tty_free_termios(struct tty_struct *tty)
{
	struct ktermios *tp;
	int idx = tty->index;
	/* Kill this flag and push into drivers for locking etc */
	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
		/* FIXME: Locking on ->termios array */
		tp = tty->termios;
		tty->driver->termios[idx] = NULL;
		kfree(tp);
	}
}
EXPORT_SYMBOL(tty_free_termios);

void tty_shutdown(struct tty_struct *tty)
{
A
Alan Cox 已提交
1372
	tty_driver_remove_tty(tty->driver, tty);
A
Alan Cox 已提交
1373 1374 1375 1376
	tty_free_termios(tty);
}
EXPORT_SYMBOL(tty_shutdown);

1377
/**
1378
 *	release_one_tty		-	release tty structure memory
A
Alan Cox 已提交
1379
 *	@kref: kref of tty we are obliterating
1380 1381 1382 1383 1384 1385 1386 1387 1388
 *
 *	Releases memory associated with a tty structure, and clears out the
 *	driver table slots. This function is called when a device is no longer
 *	in use. It also gets called when setup of a device fails.
 *
 *	Locking:
 *		tty_mutex - sometimes only
 *		takes the file list lock internally when working on the list
 *	of ttys that the driver keeps.
L
Linus Torvalds 已提交
1389
 */
A
Alan Cox 已提交
1390
static void release_one_tty(struct kref *kref)
L
Linus Torvalds 已提交
1391
{
A
Alan Cox 已提交
1392
	struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1393
	struct tty_driver *driver = tty->driver;
1394

A
Alan Cox 已提交
1395 1396 1397 1398
	if (tty->ops->shutdown)
		tty->ops->shutdown(tty);
	else
		tty_shutdown(tty);
L
Linus Torvalds 已提交
1399
	tty->magic = 0;
A
Alan Cox 已提交
1400
	tty_driver_kref_put(driver);
1401
	module_put(driver->owner);
1402

L
Linus Torvalds 已提交
1403 1404 1405
	file_list_lock();
	list_del_init(&tty->tty_files);
	file_list_unlock();
1406

L
Linus Torvalds 已提交
1407 1408 1409
	free_tty_struct(tty);
}

A
Alan Cox 已提交
1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424
/**
 *	tty_kref_put		-	release a tty kref
 *	@tty: tty device
 *
 *	Release a reference to a tty device and if need be let the kref
 *	layer destruct the object for us
 */

void tty_kref_put(struct tty_struct *tty)
{
	if (tty)
		kref_put(&tty->kref, release_one_tty);
}
EXPORT_SYMBOL(tty_kref_put);

1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
/**
 *	release_tty		-	release tty structure memory
 *
 *	Release both @tty and a possible linked partner (think pty pair),
 *	and decrement the refcount of the backing module.
 *
 *	Locking:
 *		tty_mutex - sometimes only
 *		takes the file list lock internally when working on the list
 *	of ttys that the driver keeps.
 *		FIXME: should we require tty_mutex is held here ??
A
Alan Cox 已提交
1436
 *
1437 1438 1439
 */
static void release_tty(struct tty_struct *tty, int idx)
{
A
Alan Cox 已提交
1440 1441 1442
	/* This should always be true but check for the moment */
	WARN_ON(tty->index != idx);

1443
	if (tty->link)
A
Alan Cox 已提交
1444 1445
		tty_kref_put(tty->link);
	tty_kref_put(tty);
1446 1447
}

L
Linus Torvalds 已提交
1448 1449 1450 1451 1452 1453 1454 1455
/*
 * Even releasing the tty structures is a tricky business.. We have
 * to be very careful that the structures are all released at the
 * same time, as interrupts might otherwise get the wrong pointers.
 *
 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
 * lead to double frees or releasing memory still in use.
 */
1456
void tty_release_dev(struct file *filp)
L
Linus Torvalds 已提交
1457 1458 1459
{
	struct tty_struct *tty, *o_tty;
	int	pty_master, tty_closing, o_tty_closing, do_sleep;
1460
	int	devpts;
L
Linus Torvalds 已提交
1461 1462
	int	idx;
	char	buf[64];
1463
	struct 	inode *inode;
1464

1465
	inode = filp->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
1466
	tty = (struct tty_struct *)filp->private_data;
1467
	if (tty_paranoia_check(tty, inode, "tty_release_dev"))
L
Linus Torvalds 已提交
1468 1469
		return;

1470
	check_tty_count(tty, "tty_release_dev");
L
Linus Torvalds 已提交
1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481

	tty_fasync(-1, filp, 0);

	idx = tty->index;
	pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
		      tty->driver->subtype == PTY_TYPE_MASTER);
	devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
	o_tty = tty->link;

#ifdef TTY_PARANOIA_CHECK
	if (idx < 0 || idx >= tty->driver->num) {
1482
		printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
L
Linus Torvalds 已提交
1483 1484 1485
				  "free (%s)\n", tty->name);
		return;
	}
A
Alan Cox 已提交
1486
	if (!devpts) {
L
Linus Torvalds 已提交
1487
		if (tty != tty->driver->ttys[idx]) {
1488
			printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
L
Linus Torvalds 已提交
1489 1490 1491 1492
			       "for (%s)\n", idx, tty->name);
			return;
		}
		if (tty->termios != tty->driver->termios[idx]) {
1493
			printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
L
Linus Torvalds 已提交
1494 1495 1496 1497 1498 1499 1500 1501
			       "for (%s)\n",
			       idx, tty->name);
			return;
		}
	}
#endif

#ifdef TTY_DEBUG_HANGUP
1502
	printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
L
Linus Torvalds 已提交
1503 1504 1505 1506 1507 1508 1509
	       tty_name(tty, buf), tty->count);
#endif

#ifdef TTY_PARANOIA_CHECK
	if (tty->driver->other &&
	     !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
		if (o_tty != tty->driver->other->ttys[idx]) {
1510
			printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
L
Linus Torvalds 已提交
1511 1512 1513 1514 1515
					  "not o_tty for (%s)\n",
			       idx, tty->name);
			return;
		}
		if (o_tty->termios != tty->driver->other->termios[idx]) {
1516
			printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
L
Linus Torvalds 已提交
1517 1518 1519 1520 1521
					  "not o_termios for (%s)\n",
			       idx, tty->name);
			return;
		}
		if (o_tty->link != tty) {
1522
			printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
L
Linus Torvalds 已提交
1523 1524 1525 1526
			return;
		}
	}
#endif
A
Alan Cox 已提交
1527 1528
	if (tty->ops->close)
		tty->ops->close(tty, filp);
L
Linus Torvalds 已提交
1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549

	/*
	 * Sanity check: if tty->count is going to zero, there shouldn't be
	 * any waiters on tty->read_wait or tty->write_wait.  We test the
	 * wait queues and kick everyone out _before_ actually starting to
	 * close.  This ensures that we won't block while releasing the tty
	 * structure.
	 *
	 * The test for the o_tty closing is necessary, since the master and
	 * slave sides may close in any order.  If the slave side closes out
	 * first, its count will be one, since the master side holds an open.
	 * Thus this test wouldn't be triggered at the time the slave closes,
	 * so we do it now.
	 *
	 * Note that it's possible for the tty to be opened again while we're
	 * flushing out waiters.  By recalculating the closing flags before
	 * each iteration we avoid any problems.
	 */
	while (1) {
		/* Guard against races with tty->count changes elsewhere and
		   opens on /dev/tty */
1550

I
Ingo Molnar 已提交
1551
		mutex_lock(&tty_mutex);
L
Linus Torvalds 已提交
1552 1553 1554 1555 1556 1557 1558
		tty_closing = tty->count <= 1;
		o_tty_closing = o_tty &&
			(o_tty->count <= (pty_master ? 1 : 0));
		do_sleep = 0;

		if (tty_closing) {
			if (waitqueue_active(&tty->read_wait)) {
1559
				wake_up_poll(&tty->read_wait, POLLIN);
L
Linus Torvalds 已提交
1560 1561 1562
				do_sleep++;
			}
			if (waitqueue_active(&tty->write_wait)) {
1563
				wake_up_poll(&tty->write_wait, POLLOUT);
L
Linus Torvalds 已提交
1564 1565 1566 1567 1568
				do_sleep++;
			}
		}
		if (o_tty_closing) {
			if (waitqueue_active(&o_tty->read_wait)) {
1569
				wake_up_poll(&o_tty->read_wait, POLLIN);
L
Linus Torvalds 已提交
1570 1571 1572
				do_sleep++;
			}
			if (waitqueue_active(&o_tty->write_wait)) {
1573
				wake_up_poll(&o_tty->write_wait, POLLOUT);
L
Linus Torvalds 已提交
1574 1575 1576 1577 1578 1579
				do_sleep++;
			}
		}
		if (!do_sleep)
			break;

1580
		printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
L
Linus Torvalds 已提交
1581
				    "active!\n", tty_name(tty, buf));
I
Ingo Molnar 已提交
1582
		mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
1583
		schedule();
1584
	}
L
Linus Torvalds 已提交
1585 1586

	/*
1587 1588
	 * The closing flags are now consistent with the open counts on
	 * both sides, and we've completed the last operation that could
L
Linus Torvalds 已提交
1589 1590 1591 1592
	 * block, so it's safe to proceed with closing.
	 */
	if (pty_master) {
		if (--o_tty->count < 0) {
1593
			printk(KERN_WARNING "tty_release_dev: bad pty slave count "
L
Linus Torvalds 已提交
1594 1595 1596 1597 1598 1599
					    "(%d) for %s\n",
			       o_tty->count, tty_name(o_tty, buf));
			o_tty->count = 0;
		}
	}
	if (--tty->count < 0) {
1600
		printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
L
Linus Torvalds 已提交
1601 1602 1603
		       tty->count, tty_name(tty, buf));
		tty->count = 0;
	}
1604

L
Linus Torvalds 已提交
1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623
	/*
	 * We've decremented tty->count, so we need to remove this file
	 * descriptor off the tty->tty_files list; this serves two
	 * purposes:
	 *  - check_tty_count sees the correct number of file descriptors
	 *    associated with this tty.
	 *  - do_tty_hangup no longer sees this file descriptor as
	 *    something that needs to be handled for hangups.
	 */
	file_kill(filp);
	filp->private_data = NULL;

	/*
	 * Perform some housekeeping before deciding whether to return.
	 *
	 * Set the TTY_CLOSING flag if this was the last open.  In the
	 * case of a pty we may have to wait around for the other side
	 * to close, and TTY_CLOSING makes sure we can't be reopened.
	 */
1624
	if (tty_closing)
L
Linus Torvalds 已提交
1625
		set_bit(TTY_CLOSING, &tty->flags);
1626
	if (o_tty_closing)
L
Linus Torvalds 已提交
1627 1628 1629 1630 1631 1632 1633 1634 1635
		set_bit(TTY_CLOSING, &o_tty->flags);

	/*
	 * If _either_ side is closing, make sure there aren't any
	 * processes that still think tty or o_tty is their controlling
	 * tty.
	 */
	if (tty_closing || o_tty_closing) {
		read_lock(&tasklist_lock);
1636
		session_clear_tty(tty->session);
L
Linus Torvalds 已提交
1637
		if (o_tty)
1638
			session_clear_tty(o_tty->session);
L
Linus Torvalds 已提交
1639 1640 1641
		read_unlock(&tasklist_lock);
	}

I
Ingo Molnar 已提交
1642
	mutex_unlock(&tty_mutex);
P
Paul Fulghum 已提交
1643

L
Linus Torvalds 已提交
1644 1645 1646
	/* check whether both sides are closing ... */
	if (!tty_closing || (o_tty && !o_tty_closing))
		return;
1647

L
Linus Torvalds 已提交
1648 1649 1650 1651
#ifdef TTY_DEBUG_HANGUP
	printk(KERN_DEBUG "freeing tty structure...");
#endif
	/*
1652
	 * Ask the line discipline code to release its structures
L
Linus Torvalds 已提交
1653
	 */
1654
	tty_ldisc_release(tty, o_tty);
L
Linus Torvalds 已提交
1655
	/*
1656
	 * The release_tty function takes care of the details of clearing
L
Linus Torvalds 已提交
1657 1658
	 * the slots and preserving the termios structure.
	 */
1659
	release_tty(tty, idx);
L
Linus Torvalds 已提交
1660 1661

	/* Make this pty number available for reallocation */
1662
	if (devpts)
1663
		devpts_kill_index(inode, idx);
L
Linus Torvalds 已提交
1664 1665
}

1666
/**
1667
 *	__tty_open		-	open a tty device
1668 1669
 *	@inode: inode of device file
 *	@filp: file pointer to tty
L
Linus Torvalds 已提交
1670
 *
1671 1672 1673
 *	tty_open and tty_release keep up the tty count that contains the
 *	number of opens done on a tty. We cannot use the inode-count, as
 *	different inodes might point to the same tty.
L
Linus Torvalds 已提交
1674
 *
1675 1676 1677 1678 1679 1680 1681
 *	Open-counting is needed for pty masters, as well as for keeping
 *	track of serial lines: DTR is dropped when the last close happens.
 *	(This is not done solely through tty->count, now.  - Ted 1/27/92)
 *
 *	The termios state of a pty is reset on first open so that
 *	settings don't persist across reuse.
 *
1682
 *	Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1683 1684
 *		 tty->count should protect the rest.
 *		 ->siglock protects ->signal/->sighand
L
Linus Torvalds 已提交
1685
 */
1686

1687
static int __tty_open(struct inode *inode, struct file *filp)
L
Linus Torvalds 已提交
1688
{
1689
	struct tty_struct *tty = NULL;
L
Linus Torvalds 已提交
1690 1691 1692 1693
	int noctty, retval;
	struct tty_driver *driver;
	int index;
	dev_t device = inode->i_rdev;
1694
	unsigned saved_flags = filp->f_flags;
L
Linus Torvalds 已提交
1695 1696

	nonseekable_open(inode, filp);
1697

L
Linus Torvalds 已提交
1698 1699 1700 1701
retry_open:
	noctty = filp->f_flags & O_NOCTTY;
	index  = -1;
	retval = 0;
1702

I
Ingo Molnar 已提交
1703
	mutex_lock(&tty_mutex);
L
Linus Torvalds 已提交
1704

1705
	if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1706 1707
		tty = get_current_tty();
		if (!tty) {
I
Ingo Molnar 已提交
1708
			mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
1709 1710
			return -ENXIO;
		}
A
Alan Cox 已提交
1711
		driver = tty_driver_kref_get(tty->driver);
1712
		index = tty->index;
L
Linus Torvalds 已提交
1713 1714
		filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
		/* noctty = 1; */
A
Alan Cox 已提交
1715 1716
		/* FIXME: Should we take a driver reference ? */
		tty_kref_put(tty);
L
Linus Torvalds 已提交
1717 1718 1719
		goto got_driver;
	}
#ifdef CONFIG_VT
1720
	if (device == MKDEV(TTY_MAJOR, 0)) {
L
Linus Torvalds 已提交
1721
		extern struct tty_driver *console_driver;
A
Alan Cox 已提交
1722
		driver = tty_driver_kref_get(console_driver);
L
Linus Torvalds 已提交
1723 1724 1725 1726 1727
		index = fg_console;
		noctty = 1;
		goto got_driver;
	}
#endif
1728
	if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1729 1730 1731 1732 1733 1734 1735 1736 1737
		struct tty_driver *console_driver = console_device(&index);
		if (console_driver) {
			driver = tty_driver_kref_get(console_driver);
			if (driver) {
				/* Don't let /dev/console block */
				filp->f_flags |= O_NONBLOCK;
				noctty = 1;
				goto got_driver;
			}
L
Linus Torvalds 已提交
1738
		}
I
Ingo Molnar 已提交
1739
		mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
1740 1741 1742 1743 1744
		return -ENODEV;
	}

	driver = get_tty_driver(device, &index);
	if (!driver) {
I
Ingo Molnar 已提交
1745
		mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
1746 1747 1748
		return -ENODEV;
	}
got_driver:
1749 1750
	if (!tty) {
		/* check whether we're reopening an existing tty */
1751
		tty = tty_driver_lookup_tty(driver, inode, index);
1752

1753 1754
		if (IS_ERR(tty)) {
			mutex_unlock(&tty_mutex);
1755
			return PTR_ERR(tty);
1756
		}
1757 1758 1759 1760 1761 1762 1763 1764 1765
	}

	if (tty) {
		retval = tty_reopen(tty);
		if (retval)
			tty = ERR_PTR(retval);
	} else
		tty = tty_init_dev(driver, index, 0);

I
Ingo Molnar 已提交
1766
	mutex_unlock(&tty_mutex);
A
Alan Cox 已提交
1767
	tty_driver_kref_put(driver);
1768 1769
	if (IS_ERR(tty))
		return PTR_ERR(tty);
L
Linus Torvalds 已提交
1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780

	filp->private_data = tty;
	file_move(filp, &tty->tty_files);
	check_tty_count(tty, "tty_open");
	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
	    tty->driver->subtype == PTY_TYPE_MASTER)
		noctty = 1;
#ifdef TTY_DEBUG_HANGUP
	printk(KERN_DEBUG "opening %s...", tty->name);
#endif
	if (!retval) {
A
Alan Cox 已提交
1781 1782
		if (tty->ops->open)
			retval = tty->ops->open(tty, filp);
L
Linus Torvalds 已提交
1783 1784 1785 1786 1787
		else
			retval = -ENODEV;
	}
	filp->f_flags = saved_flags;

1788 1789
	if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
						!capable(CAP_SYS_ADMIN))
L
Linus Torvalds 已提交
1790 1791 1792 1793 1794 1795 1796
		retval = -EBUSY;

	if (retval) {
#ifdef TTY_DEBUG_HANGUP
		printk(KERN_DEBUG "error %d in opening %s...", retval,
		       tty->name);
#endif
1797
		tty_release_dev(filp);
L
Linus Torvalds 已提交
1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809
		if (retval != -ERESTARTSYS)
			return retval;
		if (signal_pending(current))
			return retval;
		schedule();
		/*
		 * Need to reset f_op in case a hangup happened.
		 */
		if (filp->f_op == &hung_up_tty_fops)
			filp->f_op = &tty_fops;
		goto retry_open;
	}
1810 1811 1812

	mutex_lock(&tty_mutex);
	spin_lock_irq(&current->sighand->siglock);
L
Linus Torvalds 已提交
1813 1814 1815
	if (!noctty &&
	    current->signal->leader &&
	    !current->signal->tty &&
1816
	    tty->session == NULL)
1817
		__proc_set_tty(current, tty);
1818 1819
	spin_unlock_irq(&current->sighand->siglock);
	mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
1820 1821 1822
	return 0;
}

1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
/* BKL pushdown: scary code avoidance wrapper */
static int tty_open(struct inode *inode, struct file *filp)
{
	int ret;

	lock_kernel();
	ret = __tty_open(inode, filp);
	unlock_kernel();
	return ret;
}



L
Linus Torvalds 已提交
1836

1837 1838 1839 1840 1841 1842 1843 1844 1845
/**
 *	tty_release		-	vfs callback for close
 *	@inode: inode of tty
 *	@filp: file pointer for handle to tty
 *
 *	Called the last time each file handle is closed that references
 *	this tty. There may however be several such references.
 *
 *	Locking:
1846
 *		Takes bkl. See tty_release_dev
1847 1848
 */

1849
static int tty_release(struct inode *inode, struct file *filp)
L
Linus Torvalds 已提交
1850 1851
{
	lock_kernel();
1852
	tty_release_dev(filp);
L
Linus Torvalds 已提交
1853 1854 1855 1856
	unlock_kernel();
	return 0;
}

1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868
/**
 *	tty_poll	-	check tty status
 *	@filp: file being polled
 *	@wait: poll wait structures to update
 *
 *	Call the line discipline polling method to obtain the poll
 *	status of the device.
 *
 *	Locking: locks called line discipline but ldisc poll method
 *	may be re-entered freely by other callers.
 */

1869
static unsigned int tty_poll(struct file *filp, poll_table *wait)
L
Linus Torvalds 已提交
1870
{
1871
	struct tty_struct *tty;
L
Linus Torvalds 已提交
1872 1873 1874 1875
	struct tty_ldisc *ld;
	int ret = 0;

	tty = (struct tty_struct *)filp->private_data;
1876
	if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
L
Linus Torvalds 已提交
1877
		return 0;
1878

L
Linus Torvalds 已提交
1879
	ld = tty_ldisc_ref_wait(tty);
A
Alan Cox 已提交
1880 1881
	if (ld->ops->poll)
		ret = (ld->ops->poll)(tty, filp, wait);
L
Linus Torvalds 已提交
1882 1883 1884 1885
	tty_ldisc_deref(ld);
	return ret;
}

1886
static int tty_fasync(int fd, struct file *filp, int on)
L
Linus Torvalds 已提交
1887
{
1888
	struct tty_struct *tty;
A
Alan Cox 已提交
1889
	unsigned long flags;
J
Jonathan Corbet 已提交
1890
	int retval = 0;
L
Linus Torvalds 已提交
1891

J
Jonathan Corbet 已提交
1892
	lock_kernel();
L
Linus Torvalds 已提交
1893
	tty = (struct tty_struct *)filp->private_data;
1894
	if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
J
Jonathan Corbet 已提交
1895
		goto out;
1896

L
Linus Torvalds 已提交
1897 1898
	retval = fasync_helper(fd, filp, on, &tty->fasync);
	if (retval <= 0)
J
Jonathan Corbet 已提交
1899
		goto out;
L
Linus Torvalds 已提交
1900 1901

	if (on) {
1902 1903
		enum pid_type type;
		struct pid *pid;
L
Linus Torvalds 已提交
1904 1905
		if (!waitqueue_active(&tty->read_wait))
			tty->minimum_to_wake = 1;
A
Alan Cox 已提交
1906
		spin_lock_irqsave(&tty->ctrl_lock, flags);
1907 1908 1909 1910 1911 1912 1913
		if (tty->pgrp) {
			pid = tty->pgrp;
			type = PIDTYPE_PGID;
		} else {
			pid = task_pid(current);
			type = PIDTYPE_PID;
		}
A
Alan Cox 已提交
1914
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1915
		retval = __f_setown(filp, pid, type, 0);
L
Linus Torvalds 已提交
1916
		if (retval)
J
Jonathan Corbet 已提交
1917
			goto out;
L
Linus Torvalds 已提交
1918 1919 1920 1921
	} else {
		if (!tty->fasync && !waitqueue_active(&tty->read_wait))
			tty->minimum_to_wake = N_TTY_BUF_SIZE;
	}
J
Jonathan Corbet 已提交
1922 1923 1924 1925
	retval = 0;
out:
	unlock_kernel();
	return retval;
L
Linus Torvalds 已提交
1926 1927
}

1928 1929 1930 1931 1932
/**
 *	tiocsti			-	fake input character
 *	@tty: tty to fake input into
 *	@p: pointer to character
 *
1933
 *	Fake input to a tty device. Does the necessary locking and
1934 1935 1936 1937 1938 1939 1940
 *	input management.
 *
 *	FIXME: does not honour flow control ??
 *
 *	Locking:
 *		Called functions take tty_ldisc_lock
 *		current->signal->tty check is safe without locks
1941 1942
 *
 *	FIXME: may race normal receive processing
1943 1944
 */

L
Linus Torvalds 已提交
1945 1946 1947 1948
static int tiocsti(struct tty_struct *tty, char __user *p)
{
	char ch, mbz = 0;
	struct tty_ldisc *ld;
1949

L
Linus Torvalds 已提交
1950 1951 1952 1953
	if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (get_user(ch, p))
		return -EFAULT;
A
Al Viro 已提交
1954
	tty_audit_tiocsti(tty, ch);
L
Linus Torvalds 已提交
1955
	ld = tty_ldisc_ref_wait(tty);
A
Alan Cox 已提交
1956
	ld->ops->receive_buf(tty, &ch, &mbz, 1);
L
Linus Torvalds 已提交
1957 1958 1959 1960
	tty_ldisc_deref(ld);
	return 0;
}

1961 1962 1963 1964 1965
/**
 *	tiocgwinsz		-	implement window query ioctl
 *	@tty; tty
 *	@arg: user buffer for result
 *
A
Alan Cox 已提交
1966
 *	Copies the kernel idea of the window size into the user buffer.
1967
 *
1968
 *	Locking: tty->termios_mutex is taken to ensure the winsize data
A
Alan Cox 已提交
1969
 *		is consistent.
1970 1971
 */

1972
static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
L
Linus Torvalds 已提交
1973
{
A
Alan Cox 已提交
1974 1975
	int err;

1976
	mutex_lock(&tty->termios_mutex);
A
Alan Cox 已提交
1977
	err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
1978
	mutex_unlock(&tty->termios_mutex);
A
Alan Cox 已提交
1979 1980

	return err ? -EFAULT: 0;
L
Linus Torvalds 已提交
1981 1982
}

1983
/**
1984 1985 1986 1987 1988 1989 1990
 *	tty_do_resize		-	resize event
 *	@tty: tty being resized
 *	@rows: rows (character)
 *	@cols: cols (character)
 *
 *	Update the termios variables and send the neccessary signals to
 *	peform a terminal resize correctly
1991 1992
 */

A
Alan Cox 已提交
1993
int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
L
Linus Torvalds 已提交
1994
{
A
Alan Cox 已提交
1995
	struct pid *pgrp;
A
Alan Cox 已提交
1996
	unsigned long flags;
L
Linus Torvalds 已提交
1997

A
Alan Cox 已提交
1998 1999 2000
	/* Lock the tty */
	mutex_lock(&tty->termios_mutex);
	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
A
Alan Cox 已提交
2001
		goto done;
A
Alan Cox 已提交
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
	/* Get the PID values and reference them so we can
	   avoid holding the tty ctrl lock while sending signals */
	spin_lock_irqsave(&tty->ctrl_lock, flags);
	pgrp = get_pid(tty->pgrp);
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);

	if (pgrp)
		kill_pgrp(pgrp, SIGWINCH, 1);
	put_pid(pgrp);

2012
	tty->winsize = *ws;
A
Alan Cox 已提交
2013
done:
A
Alan Cox 已提交
2014
	mutex_unlock(&tty->termios_mutex);
L
Linus Torvalds 已提交
2015 2016 2017
	return 0;
}

2018 2019
/**
 *	tiocswinsz		-	implement window size set ioctl
A
Alan Cox 已提交
2020
 *	@tty; tty side of tty
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032
 *	@arg: user buffer for result
 *
 *	Copies the user idea of the window size to the kernel. Traditionally
 *	this is just advisory information but for the Linux console it
 *	actually has driver level meaning and triggers a VC resize.
 *
 *	Locking:
 *		Driver dependant. The default do_resize method takes the
 *	tty termios mutex and ctrl_lock. The console takes its own lock
 *	then calls into the default method.
 */

A
Alan Cox 已提交
2033
static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2034 2035 2036 2037 2038 2039
{
	struct winsize tmp_ws;
	if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
		return -EFAULT;

	if (tty->ops->resize)
A
Alan Cox 已提交
2040
		return tty->ops->resize(tty, &tmp_ws);
2041
	else
A
Alan Cox 已提交
2042
		return tty_do_resize(tty, &tmp_ws);
2043 2044
}

2045 2046 2047 2048 2049 2050 2051 2052 2053
/**
 *	tioccons	-	allow admin to move logical console
 *	@file: the file to become console
 *
 *	Allow the adminstrator to move the redirected console device
 *
 *	Locking: uses redirect_lock to guard the redirect information
 */

L
Linus Torvalds 已提交
2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078
static int tioccons(struct file *file)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	if (file->f_op->write == redirected_tty_write) {
		struct file *f;
		spin_lock(&redirect_lock);
		f = redirect;
		redirect = NULL;
		spin_unlock(&redirect_lock);
		if (f)
			fput(f);
		return 0;
	}
	spin_lock(&redirect_lock);
	if (redirect) {
		spin_unlock(&redirect_lock);
		return -EBUSY;
	}
	get_file(file);
	redirect = file;
	spin_unlock(&redirect_lock);
	return 0;
}

2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089
/**
 *	fionbio		-	non blocking ioctl
 *	@file: file to set blocking value
 *	@p: user parameter
 *
 *	Historical tty interfaces had a blocking control ioctl before
 *	the generic functionality existed. This piece of history is preserved
 *	in the expected tty API of posix OS's.
 *
 *	Locking: none, the open fle handle ensures it won't go away.
 */
L
Linus Torvalds 已提交
2090 2091 2092 2093 2094 2095 2096 2097

static int fionbio(struct file *file, int __user *p)
{
	int nonblock;

	if (get_user(nonblock, p))
		return -EFAULT;

J
Jonathan Corbet 已提交
2098
	spin_lock(&file->f_lock);
L
Linus Torvalds 已提交
2099 2100 2101 2102
	if (nonblock)
		file->f_flags |= O_NONBLOCK;
	else
		file->f_flags &= ~O_NONBLOCK;
J
Jonathan Corbet 已提交
2103
	spin_unlock(&file->f_lock);
L
Linus Torvalds 已提交
2104 2105 2106
	return 0;
}

2107 2108 2109 2110 2111 2112 2113 2114 2115
/**
 *	tiocsctty	-	set controlling tty
 *	@tty: tty structure
 *	@arg: user argument
 *
 *	This ioctl is used to manage job control. It permits a session
 *	leader to set this tty as the controlling tty for the session.
 *
 *	Locking:
2116
 *		Takes tty_mutex() to protect tty instance
2117 2118
 *		Takes tasklist_lock internally to walk sessions
 *		Takes ->siglock() when updating signal->tty
2119 2120
 */

L
Linus Torvalds 已提交
2121 2122
static int tiocsctty(struct tty_struct *tty, int arg)
{
2123
	int ret = 0;
2124
	if (current->signal->leader && (task_session(current) == tty->session))
2125 2126 2127
		return ret;

	mutex_lock(&tty_mutex);
L
Linus Torvalds 已提交
2128 2129 2130 2131
	/*
	 * The process must be a session leader and
	 * not have a controlling tty already.
	 */
2132 2133 2134 2135 2136
	if (!current->signal->leader || current->signal->tty) {
		ret = -EPERM;
		goto unlock;
	}

2137
	if (tty->session) {
L
Linus Torvalds 已提交
2138 2139 2140 2141
		/*
		 * This tty is already the controlling
		 * tty for another session group!
		 */
2142
		if (arg == 1 && capable(CAP_SYS_ADMIN)) {
L
Linus Torvalds 已提交
2143 2144 2145 2146
			/*
			 * Steal it away
			 */
			read_lock(&tasklist_lock);
2147
			session_clear_tty(tty->session);
L
Linus Torvalds 已提交
2148
			read_unlock(&tasklist_lock);
2149 2150 2151 2152
		} else {
			ret = -EPERM;
			goto unlock;
		}
L
Linus Torvalds 已提交
2153
	}
2154 2155
	proc_set_tty(current, tty);
unlock:
2156
	mutex_unlock(&tty_mutex);
2157
	return ret;
L
Linus Torvalds 已提交
2158 2159
}

2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180
/**
 *	tty_get_pgrp	-	return a ref counted pgrp pid
 *	@tty: tty to read
 *
 *	Returns a refcounted instance of the pid struct for the process
 *	group controlling the tty.
 */

struct pid *tty_get_pgrp(struct tty_struct *tty)
{
	unsigned long flags;
	struct pid *pgrp;

	spin_lock_irqsave(&tty->ctrl_lock, flags);
	pgrp = get_pid(tty->pgrp);
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);

	return pgrp;
}
EXPORT_SYMBOL_GPL(tty_get_pgrp);

2181 2182 2183 2184 2185 2186 2187 2188 2189
/**
 *	tiocgpgrp		-	get process group
 *	@tty: tty passed by user
 *	@real_tty: tty side of the tty pased by the user if a pty else the tty
 *	@p: returned pid
 *
 *	Obtain the process group of the tty. If there is no process group
 *	return an error.
 *
2190
 *	Locking: none. Reference to current->signal->tty is safe.
2191 2192
 */

L
Linus Torvalds 已提交
2193 2194
static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
2195 2196
	struct pid *pid;
	int ret;
L
Linus Torvalds 已提交
2197 2198 2199 2200 2201 2202
	/*
	 * (tty == real_tty) is a cheap way of
	 * testing if the tty is NOT a master pty.
	 */
	if (tty == real_tty && current->signal->tty != real_tty)
		return -ENOTTY;
2203 2204 2205 2206
	pid = tty_get_pgrp(real_tty);
	ret =  put_user(pid_vnr(pid), p);
	put_pid(pid);
	return ret;
L
Linus Torvalds 已提交
2207 2208
}

2209 2210 2211 2212 2213 2214 2215 2216 2217
/**
 *	tiocspgrp		-	attempt to set process group
 *	@tty: tty passed by user
 *	@real_tty: tty side device matching tty passed by user
 *	@p: pid pointer
 *
 *	Set the process group of the tty to the session passed. Only
 *	permitted where the tty session is our session.
 *
A
Alan Cox 已提交
2218
 *	Locking: RCU, ctrl lock
2219 2220
 */

L
Linus Torvalds 已提交
2221 2222
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
2223 2224
	struct pid *pgrp;
	pid_t pgrp_nr;
L
Linus Torvalds 已提交
2225
	int retval = tty_check_change(real_tty);
A
Alan Cox 已提交
2226
	unsigned long flags;
L
Linus Torvalds 已提交
2227 2228 2229 2230 2231 2232 2233

	if (retval == -EIO)
		return -ENOTTY;
	if (retval)
		return retval;
	if (!current->signal->tty ||
	    (current->signal->tty != real_tty) ||
2234
	    (real_tty->session != task_session(current)))
L
Linus Torvalds 已提交
2235
		return -ENOTTY;
2236
	if (get_user(pgrp_nr, p))
L
Linus Torvalds 已提交
2237
		return -EFAULT;
2238
	if (pgrp_nr < 0)
L
Linus Torvalds 已提交
2239
		return -EINVAL;
2240
	rcu_read_lock();
2241
	pgrp = find_vpid(pgrp_nr);
2242 2243 2244 2245 2246 2247 2248
	retval = -ESRCH;
	if (!pgrp)
		goto out_unlock;
	retval = -EPERM;
	if (session_of_pgrp(pgrp) != task_session(current))
		goto out_unlock;
	retval = 0;
A
Alan Cox 已提交
2249
	spin_lock_irqsave(&tty->ctrl_lock, flags);
2250 2251
	put_pid(real_tty->pgrp);
	real_tty->pgrp = get_pid(pgrp);
A
Alan Cox 已提交
2252
	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2253 2254 2255
out_unlock:
	rcu_read_unlock();
	return retval;
L
Linus Torvalds 已提交
2256 2257
}

2258 2259 2260 2261 2262 2263 2264 2265 2266
/**
 *	tiocgsid		-	get session id
 *	@tty: tty passed by user
 *	@real_tty: tty side of the tty pased by the user if a pty else the tty
 *	@p: pointer to returned session id
 *
 *	Obtain the session id of the tty. If there is no session
 *	return an error.
 *
2267
 *	Locking: none. Reference to current->signal->tty is safe.
2268 2269
 */

L
Linus Torvalds 已提交
2270 2271 2272 2273 2274 2275 2276 2277
static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
{
	/*
	 * (tty == real_tty) is a cheap way of
	 * testing if the tty is NOT a master pty.
	*/
	if (tty == real_tty && current->signal->tty != real_tty)
		return -ENOTTY;
2278
	if (!real_tty->session)
L
Linus Torvalds 已提交
2279
		return -ENOTTY;
2280
	return put_user(pid_vnr(real_tty->session), p);
L
Linus Torvalds 已提交
2281 2282
}

2283 2284 2285 2286 2287 2288 2289 2290 2291 2292
/**
 *	tiocsetd	-	set line discipline
 *	@tty: tty device
 *	@p: pointer to user data
 *
 *	Set the line discipline according to user request.
 *
 *	Locking: see tty_set_ldisc, this function is just a helper
 */

L
Linus Torvalds 已提交
2293 2294 2295
static int tiocsetd(struct tty_struct *tty, int __user *p)
{
	int ldisc;
A
Alan Cox 已提交
2296
	int ret;
L
Linus Torvalds 已提交
2297 2298 2299

	if (get_user(ldisc, p))
		return -EFAULT;
A
Alan Cox 已提交
2300 2301 2302 2303 2304 2305

	lock_kernel();
	ret = tty_set_ldisc(tty, ldisc);
	unlock_kernel();

	return ret;
L
Linus Torvalds 已提交
2306 2307
}

2308 2309 2310 2311 2312 2313 2314 2315 2316
/**
 *	send_break	-	performed time break
 *	@tty: device to break on
 *	@duration: timeout in mS
 *
 *	Perform a timed break on hardware that lacks its own driver level
 *	timed break functionality.
 *
 *	Locking:
2317
 *		atomic_write_lock serializes
2318 2319 2320
 *
 */

2321
static int send_break(struct tty_struct *tty, unsigned int duration)
L
Linus Torvalds 已提交
2322
{
A
Alan Cox 已提交
2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345
	int retval;

	if (tty->ops->break_ctl == NULL)
		return 0;

	if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
		retval = tty->ops->break_ctl(tty, duration);
	else {
		/* Do the work ourselves */
		if (tty_write_lock(tty, 0) < 0)
			return -EINTR;
		retval = tty->ops->break_ctl(tty, -1);
		if (retval)
			goto out;
		if (!signal_pending(current))
			msleep_interruptible(duration);
		retval = tty->ops->break_ctl(tty, 0);
out:
		tty_write_unlock(tty);
		if (signal_pending(current))
			retval = -EINTR;
	}
	return retval;
L
Linus Torvalds 已提交
2346 2347
}

2348
/**
A
Alan Cox 已提交
2349
 *	tty_tiocmget		-	get modem status
2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360
 *	@tty: tty device
 *	@file: user file pointer
 *	@p: pointer to result
 *
 *	Obtain the modem status bits from the tty driver if the feature
 *	is supported. Return -EINVAL if it is not available.
 *
 *	Locking: none (up to the driver)
 */

static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
L
Linus Torvalds 已提交
2361 2362 2363
{
	int retval = -EINVAL;

A
Alan Cox 已提交
2364 2365
	if (tty->ops->tiocmget) {
		retval = tty->ops->tiocmget(tty, file);
L
Linus Torvalds 已提交
2366 2367 2368 2369 2370 2371 2372

		if (retval >= 0)
			retval = put_user(retval, p);
	}
	return retval;
}

2373
/**
A
Alan Cox 已提交
2374
 *	tty_tiocmset		-	set modem status
2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386
 *	@tty: tty device
 *	@file: user file pointer
 *	@cmd: command - clear bits, set bits or set all
 *	@p: pointer to desired bits
 *
 *	Set the modem status bits from the tty driver if the feature
 *	is supported. Return -EINVAL if it is not available.
 *
 *	Locking: none (up to the driver)
 */

static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
L
Linus Torvalds 已提交
2387 2388
	     unsigned __user *p)
{
A
Alan Cox 已提交
2389 2390
	int retval;
	unsigned int set, clear, val;
L
Linus Torvalds 已提交
2391

A
Alan Cox 已提交
2392 2393
	if (tty->ops->tiocmset == NULL)
		return -EINVAL;
L
Linus Torvalds 已提交
2394

A
Alan Cox 已提交
2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413
	retval = get_user(val, p);
	if (retval)
		return retval;
	set = clear = 0;
	switch (cmd) {
	case TIOCMBIS:
		set = val;
		break;
	case TIOCMBIC:
		clear = val;
		break;
	case TIOCMSET:
		set = val;
		clear = ~val;
		break;
	}
	set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
	clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
	return tty->ops->tiocmset(tty, file, set, clear);
L
Linus Torvalds 已提交
2414 2415
}

2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433
struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
{
	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
	    tty->driver->subtype == PTY_TYPE_MASTER)
		tty = tty->link;
	return tty;
}
EXPORT_SYMBOL(tty_pair_get_tty);

struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
{
	if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
	    tty->driver->subtype == PTY_TYPE_MASTER)
	    return tty;
	return tty->link;
}
EXPORT_SYMBOL(tty_pair_get_pty);

L
Linus Torvalds 已提交
2434 2435 2436
/*
 * Split this up, as gcc can choke on it otherwise..
 */
A
Alan Cox 已提交
2437
long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
L
Linus Torvalds 已提交
2438 2439 2440 2441 2442
{
	struct tty_struct *tty, *real_tty;
	void __user *p = (void __user *)arg;
	int retval;
	struct tty_ldisc *ld;
A
Alan Cox 已提交
2443
	struct inode *inode = file->f_dentry->d_inode;
2444

L
Linus Torvalds 已提交
2445 2446 2447 2448
	tty = (struct tty_struct *)file->private_data;
	if (tty_paranoia_check(tty, inode, "tty_ioctl"))
		return -EINVAL;

2449
	real_tty = tty_pair_get_tty(tty);
L
Linus Torvalds 已提交
2450 2451 2452 2453 2454 2455 2456 2457 2458

	/*
	 * Factor out some common prep work
	 */
	switch (cmd) {
	case TIOCSETD:
	case TIOCSBRK:
	case TIOCCBRK:
	case TCSBRK:
2459
	case TCSBRKP:
L
Linus Torvalds 已提交
2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470
		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;
	}

A
Alan Cox 已提交
2471 2472 2473
	/*
	 *	Now do the stuff.
	 */
L
Linus Torvalds 已提交
2474
	switch (cmd) {
2475 2476 2477
	case TIOCSTI:
		return tiocsti(tty, p);
	case TIOCGWINSZ:
2478
		return tiocgwinsz(real_tty, p);
2479
	case TIOCSWINSZ:
A
Alan Cox 已提交
2480
		return tiocswinsz(real_tty, p);
2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504
	case TIOCCONS:
		return real_tty != tty ? -EINVAL : tioccons(file);
	case FIONBIO:
		return fionbio(file, p);
	case TIOCEXCL:
		set_bit(TTY_EXCLUSIVE, &tty->flags);
		return 0;
	case TIOCNXCL:
		clear_bit(TTY_EXCLUSIVE, &tty->flags);
		return 0;
	case TIOCNOTTY:
		if (current->signal->tty != tty)
			return -ENOTTY;
		no_tty();
		return 0;
	case TIOCSCTTY:
		return tiocsctty(tty, arg);
	case TIOCGPGRP:
		return tiocgpgrp(tty, real_tty, p);
	case TIOCSPGRP:
		return tiocspgrp(tty, real_tty, p);
	case TIOCGSID:
		return tiocgsid(tty, real_tty, p);
	case TIOCGETD:
A
Alan Cox 已提交
2505
		return put_user(tty->ldisc->ops->num, (int __user *)p);
2506 2507 2508 2509 2510 2511
	case TIOCSETD:
		return tiocsetd(tty, p);
	/*
	 * Break handling
	 */
	case TIOCSBRK:	/* Turn break on, unconditionally */
A
Alan Cox 已提交
2512
		if (tty->ops->break_ctl)
A
Alan Cox 已提交
2513
			return tty->ops->break_ctl(tty, -1);
2514 2515
		return 0;
	case TIOCCBRK:	/* Turn break off, unconditionally */
A
Alan Cox 已提交
2516
		if (tty->ops->break_ctl)
A
Alan Cox 已提交
2517
			return tty->ops->break_ctl(tty, 0);
2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541
		return 0;
	case TCSBRK:   /* SVID version: non-zero arg --> no break */
		/* non-zero arg means wait for all output data
		 * to be sent (performed above) but don't send break.
		 * This is used by the tcdrain() termios function.
		 */
		if (!arg)
			return send_break(tty, 250);
		return 0;
	case TCSBRKP:	/* support for POSIX tcsendbreak() */
		return send_break(tty, arg ? arg*100 : 250);

	case TIOCMGET:
		return tty_tiocmget(tty, file, p);
	case TIOCMSET:
	case TIOCMBIC:
	case TIOCMBIS:
		return tty_tiocmset(tty, file, cmd, p);
	case TCFLSH:
		switch (arg) {
		case TCIFLUSH:
		case TCIOFLUSH:
		/* flush tty buffer and allow ldisc to process ioctl */
			tty_buffer_flush(tty);
2542
			break;
2543 2544
		}
		break;
L
Linus Torvalds 已提交
2545
	}
A
Alan Cox 已提交
2546 2547
	if (tty->ops->ioctl) {
		retval = (tty->ops->ioctl)(tty, file, cmd, arg);
L
Linus Torvalds 已提交
2548 2549 2550 2551 2552
		if (retval != -ENOIOCTLCMD)
			return retval;
	}
	ld = tty_ldisc_ref_wait(tty);
	retval = -EINVAL;
A
Alan Cox 已提交
2553 2554
	if (ld->ops->ioctl) {
		retval = ld->ops->ioctl(tty, file, cmd, arg);
L
Linus Torvalds 已提交
2555 2556 2557 2558 2559 2560 2561
		if (retval == -ENOIOCTLCMD)
			retval = -EINVAL;
	}
	tty_ldisc_deref(ld);
	return retval;
}

P
Paul Fulghum 已提交
2562
#ifdef CONFIG_COMPAT
2563
static long tty_compat_ioctl(struct file *file, unsigned int cmd,
P
Paul Fulghum 已提交
2564 2565 2566 2567 2568 2569 2570 2571 2572 2573
				unsigned long arg)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct tty_struct *tty = file->private_data;
	struct tty_ldisc *ld;
	int retval = -ENOIOCTLCMD;

	if (tty_paranoia_check(tty, inode, "tty_ioctl"))
		return -EINVAL;

A
Alan Cox 已提交
2574 2575
	if (tty->ops->compat_ioctl) {
		retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
P
Paul Fulghum 已提交
2576 2577 2578 2579 2580
		if (retval != -ENOIOCTLCMD)
			return retval;
	}

	ld = tty_ldisc_ref_wait(tty);
A
Alan Cox 已提交
2581 2582
	if (ld->ops->compat_ioctl)
		retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
P
Paul Fulghum 已提交
2583 2584 2585 2586 2587
	tty_ldisc_deref(ld);

	return retval;
}
#endif
L
Linus Torvalds 已提交
2588 2589 2590 2591 2592 2593

/*
 * 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.
2594
 *
L
Linus Torvalds 已提交
2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607
 * 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.
 *
 * Now, if it would be correct ;-/ The current code has a nasty hole -
 * it doesn't catch files in flight. We may send the descriptor to ourselves
 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
 *
 * Nasty bug: do_SAK is being called in interrupt context.  This can
 * deadlock.  We punt it up to process context.  AKPM - 16Mar2001
 */
2608
void __do_SAK(struct tty_struct *tty)
L
Linus Torvalds 已提交
2609 2610 2611 2612
{
#ifdef TTY_SOFT_SAK
	tty_hangup(tty);
#else
2613
	struct task_struct *g, *p;
2614
	struct pid *session;
L
Linus Torvalds 已提交
2615 2616
	int		i;
	struct file	*filp;
2617
	struct fdtable *fdt;
2618

L
Linus Torvalds 已提交
2619 2620
	if (!tty)
		return;
2621
	session = tty->session;
2622

2623
	tty_ldisc_flush(tty);
L
Linus Torvalds 已提交
2624

A
Alan Cox 已提交
2625
	tty_driver_flush_buffer(tty);
2626

L
Linus Torvalds 已提交
2627
	read_lock(&tasklist_lock);
2628
	/* Kill the entire session */
2629
	do_each_pid_task(session, PIDTYPE_SID, p) {
2630
		printk(KERN_NOTICE "SAK: killed process %d"
2631
			" (%s): task_session(p)==tty->session\n",
2632
			task_pid_nr(p), p->comm);
2633
		send_sig(SIGKILL, p, 1);
2634
	} while_each_pid_task(session, PIDTYPE_SID, p);
2635 2636 2637 2638 2639
	/* Now kill any processes that happen to have the
	 * tty open.
	 */
	do_each_thread(g, p) {
		if (p->signal->tty == tty) {
L
Linus Torvalds 已提交
2640
			printk(KERN_NOTICE "SAK: killed process %d"
2641
			    " (%s): task_session(p)==tty->session\n",
2642
			    task_pid_nr(p), p->comm);
L
Linus Torvalds 已提交
2643 2644 2645 2646 2647
			send_sig(SIGKILL, p, 1);
			continue;
		}
		task_lock(p);
		if (p->files) {
2648 2649 2650 2651 2652
			/*
			 * We don't take a ref to the file, so we must
			 * hold ->file_lock instead.
			 */
			spin_lock(&p->files->file_lock);
2653
			fdt = files_fdtable(p->files);
2654
			for (i = 0; i < fdt->max_fds; i++) {
L
Linus Torvalds 已提交
2655 2656 2657 2658 2659 2660 2661
				filp = fcheck_files(p->files, i);
				if (!filp)
					continue;
				if (filp->f_op->read == tty_read &&
				    filp->private_data == tty) {
					printk(KERN_NOTICE "SAK: killed process %d"
					    " (%s): fd#%d opened to the tty\n",
2662
					    task_pid_nr(p), p->comm, i);
2663
					force_sig(SIGKILL, p);
L
Linus Torvalds 已提交
2664 2665 2666
					break;
				}
			}
2667
			spin_unlock(&p->files->file_lock);
L
Linus Torvalds 已提交
2668 2669
		}
		task_unlock(p);
2670
	} while_each_thread(g, p);
L
Linus Torvalds 已提交
2671 2672 2673 2674
	read_unlock(&tasklist_lock);
#endif
}

2675 2676 2677 2678 2679 2680 2681
static void do_SAK_work(struct work_struct *work)
{
	struct tty_struct *tty =
		container_of(work, struct tty_struct, SAK_work);
	__do_SAK(tty);
}

L
Linus Torvalds 已提交
2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696
/*
 * The tq handling here is a little racy - tty->SAK_work may already be queued.
 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
 * the values which we write to it will be identical to the values which it
 * already has. --akpm
 */
void do_SAK(struct tty_struct *tty)
{
	if (!tty)
		return;
	schedule_work(&tty->SAK_work);
}

EXPORT_SYMBOL(do_SAK);

2697 2698 2699 2700 2701 2702 2703 2704
/**
 *	initialize_tty_struct
 *	@tty: tty to initialize
 *
 *	This subroutine initializes a tty structure that has been newly
 *	allocated.
 *
 *	Locking: none - tty in question must not be exposed at this point
L
Linus Torvalds 已提交
2705
 */
2706

2707 2708
void initialize_tty_struct(struct tty_struct *tty,
		struct tty_driver *driver, int idx)
L
Linus Torvalds 已提交
2709 2710
{
	memset(tty, 0, sizeof(struct tty_struct));
A
Alan Cox 已提交
2711
	kref_init(&tty->kref);
L
Linus Torvalds 已提交
2712
	tty->magic = TTY_MAGIC;
2713
	tty_ldisc_init(tty);
2714 2715
	tty->session = NULL;
	tty->pgrp = NULL;
L
Linus Torvalds 已提交
2716
	tty->overrun_time = jiffies;
A
Alan Cox 已提交
2717 2718
	tty->buf.head = tty->buf.tail = NULL;
	tty_buffer_init(tty);
2719
	mutex_init(&tty->termios_mutex);
A
Alan Cox 已提交
2720
	mutex_init(&tty->ldisc_mutex);
L
Linus Torvalds 已提交
2721 2722
	init_waitqueue_head(&tty->write_wait);
	init_waitqueue_head(&tty->read_wait);
2723
	INIT_WORK(&tty->hangup_work, do_tty_hangup);
I
Ingo Molnar 已提交
2724 2725
	mutex_init(&tty->atomic_read_lock);
	mutex_init(&tty->atomic_write_lock);
2726 2727
	mutex_init(&tty->output_lock);
	mutex_init(&tty->echo_lock);
L
Linus Torvalds 已提交
2728
	spin_lock_init(&tty->read_lock);
A
Alan Cox 已提交
2729
	spin_lock_init(&tty->ctrl_lock);
L
Linus Torvalds 已提交
2730
	INIT_LIST_HEAD(&tty->tty_files);
2731
	INIT_WORK(&tty->SAK_work, do_SAK_work);
2732 2733 2734 2735 2736

	tty->driver = driver;
	tty->ops = driver->ops;
	tty->index = idx;
	tty_line_name(driver, idx, tty->name);
L
Linus Torvalds 已提交
2737 2738
}

A
Alan Cox 已提交
2739 2740 2741 2742 2743 2744 2745 2746 2747 2748
/**
 *	tty_put_char	-	write one character to a tty
 *	@tty: tty
 *	@ch: character
 *
 *	Write one byte to the tty using the provided put_char method
 *	if present. Returns the number of characters successfully output.
 *
 *	Note: the specific put_char operation in the driver layer may go
 *	away soon. Don't call it directly, use this method
L
Linus Torvalds 已提交
2749
 */
2750

A
Alan Cox 已提交
2751
int tty_put_char(struct tty_struct *tty, unsigned char ch)
L
Linus Torvalds 已提交
2752
{
A
Alan Cox 已提交
2753 2754 2755
	if (tty->ops->put_char)
		return tty->ops->put_char(tty, ch);
	return tty->ops->write(tty, &ch, 1);
L
Linus Torvalds 已提交
2756
}
A
Alan Cox 已提交
2757 2758
EXPORT_SYMBOL_GPL(tty_put_char);

2759
struct class *tty_class;
L
Linus Torvalds 已提交
2760 2761

/**
2762 2763 2764 2765 2766 2767
 *	tty_register_device - register a tty device
 *	@driver: the tty driver that describes the tty device
 *	@index: the index in the tty driver for this tty device
 *	@device: a struct device that is associated with this tty device.
 *		This field is optional, if there is no known struct device
 *		for this tty device it can be set to NULL safely.
L
Linus Torvalds 已提交
2768
 *
2769 2770
 *	Returns a pointer to the struct device for this tty device
 *	(or ERR_PTR(-EFOO) on error).
2771
 *
2772 2773 2774 2775 2776 2777
 *	This call is required to be made to register an individual tty device
 *	if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set.  If
 *	that bit is not set, this function should not be called by a tty
 *	driver.
 *
 *	Locking: ??
L
Linus Torvalds 已提交
2778
 */
2779

2780 2781
struct device *tty_register_device(struct tty_driver *driver, unsigned index,
				   struct device *device)
L
Linus Torvalds 已提交
2782 2783 2784 2785 2786 2787 2788
{
	char name[64];
	dev_t dev = MKDEV(driver->major, driver->minor_start) + index;

	if (index >= driver->num) {
		printk(KERN_ERR "Attempt to register invalid tty line number "
		       " (%d).\n", index);
2789
		return ERR_PTR(-EINVAL);
L
Linus Torvalds 已提交
2790 2791 2792 2793 2794 2795
	}

	if (driver->type == TTY_DRIVER_TYPE_PTY)
		pty_line_name(driver, index, name);
	else
		tty_line_name(driver, index, name);
2796

2797
	return device_create(tty_class, device, dev, NULL, name);
L
Linus Torvalds 已提交
2798
}
A
Alan Cox 已提交
2799
EXPORT_SYMBOL(tty_register_device);
L
Linus Torvalds 已提交
2800 2801

/**
2802 2803 2804
 * 	tty_unregister_device - unregister a tty device
 * 	@driver: the tty driver that describes the tty device
 * 	@index: the index in the tty driver for this tty device
L
Linus Torvalds 已提交
2805
 *
2806 2807 2808 2809
 * 	If a tty device is registered with a call to tty_register_device() then
 *	this function must be called when the tty device is gone.
 *
 *	Locking: ??
L
Linus Torvalds 已提交
2810
 */
2811

L
Linus Torvalds 已提交
2812 2813
void tty_unregister_device(struct tty_driver *driver, unsigned index)
{
2814 2815
	device_destroy(tty_class,
		MKDEV(driver->major, driver->minor_start) + index);
L
Linus Torvalds 已提交
2816 2817 2818 2819 2820 2821 2822
}
EXPORT_SYMBOL(tty_unregister_device);

struct tty_driver *alloc_tty_driver(int lines)
{
	struct tty_driver *driver;

J
Jean Delvare 已提交
2823
	driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
L
Linus Torvalds 已提交
2824
	if (driver) {
A
Alan Cox 已提交
2825
		kref_init(&driver->kref);
L
Linus Torvalds 已提交
2826 2827 2828 2829 2830 2831
		driver->magic = TTY_DRIVER_MAGIC;
		driver->num = lines;
		/* later we'll move allocation of tables here */
	}
	return driver;
}
A
Alan Cox 已提交
2832
EXPORT_SYMBOL(alloc_tty_driver);
L
Linus Torvalds 已提交
2833

A
Alan Cox 已提交
2834
static void destruct_tty_driver(struct kref *kref)
L
Linus Torvalds 已提交
2835
{
A
Alan Cox 已提交
2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858
	struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
	int i;
	struct ktermios *tp;
	void *p;

	if (driver->flags & TTY_DRIVER_INSTALLED) {
		/*
		 * Free the termios and termios_locked structures because
		 * we don't want to get memory leaks when modular tty
		 * drivers are removed from the kernel.
		 */
		for (i = 0; i < driver->num; i++) {
			tp = driver->termios[i];
			if (tp) {
				driver->termios[i] = NULL;
				kfree(tp);
			}
			if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
				tty_unregister_device(driver, i);
		}
		p = driver->ttys;
		proc_tty_unregister_driver(driver);
		driver->ttys = NULL;
A
Alan Cox 已提交
2859
		driver->termios = NULL;
A
Alan Cox 已提交
2860 2861 2862
		kfree(p);
		cdev_del(&driver->cdev);
	}
L
Linus Torvalds 已提交
2863 2864 2865
	kfree(driver);
}

A
Alan Cox 已提交
2866 2867 2868 2869 2870 2871
void tty_driver_kref_put(struct tty_driver *driver)
{
	kref_put(&driver->kref, destruct_tty_driver);
}
EXPORT_SYMBOL(tty_driver_kref_put);

J
Jeff Dike 已提交
2872 2873
void tty_set_operations(struct tty_driver *driver,
			const struct tty_operations *op)
L
Linus Torvalds 已提交
2874
{
A
Alan Cox 已提交
2875 2876
	driver->ops = op;
};
A
Alan Cox 已提交
2877
EXPORT_SYMBOL(tty_set_operations);
L
Linus Torvalds 已提交
2878

A
Alan Cox 已提交
2879 2880 2881 2882
void put_tty_driver(struct tty_driver *d)
{
	tty_driver_kref_put(d);
}
L
Linus Torvalds 已提交
2883 2884 2885 2886 2887 2888 2889 2890
EXPORT_SYMBOL(put_tty_driver);

/*
 * Called by a tty driver to register itself.
 */
int tty_register_driver(struct tty_driver *driver)
{
	int error;
2891
	int i;
L
Linus Torvalds 已提交
2892 2893 2894
	dev_t dev;
	void **p = NULL;

2895
	if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
A
Alan Cox 已提交
2896
		p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
L
Linus Torvalds 已提交
2897 2898 2899 2900 2901
		if (!p)
			return -ENOMEM;
	}

	if (!driver->major) {
2902 2903
		error = alloc_chrdev_region(&dev, driver->minor_start,
						driver->num, driver->name);
L
Linus Torvalds 已提交
2904 2905 2906 2907 2908 2909
		if (!error) {
			driver->major = MAJOR(dev);
			driver->minor_start = MINOR(dev);
		}
	} else {
		dev = MKDEV(driver->major, driver->minor_start);
2910
		error = register_chrdev_region(dev, driver->num, driver->name);
L
Linus Torvalds 已提交
2911 2912 2913 2914 2915 2916 2917 2918
	}
	if (error < 0) {
		kfree(p);
		return error;
	}

	if (p) {
		driver->ttys = (struct tty_struct **)p;
2919
		driver->termios = (struct ktermios **)(p + driver->num);
L
Linus Torvalds 已提交
2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930
	} else {
		driver->ttys = NULL;
		driver->termios = NULL;
	}

	cdev_init(&driver->cdev, &tty_fops);
	driver->cdev.owner = driver->owner;
	error = cdev_add(&driver->cdev, dev, driver->num);
	if (error) {
		unregister_chrdev_region(dev, driver->num);
		driver->ttys = NULL;
A
Alan Cox 已提交
2931
		driver->termios = NULL;
L
Linus Torvalds 已提交
2932 2933 2934 2935
		kfree(p);
		return error;
	}

2936
	mutex_lock(&tty_mutex);
L
Linus Torvalds 已提交
2937
	list_add(&driver->tty_drivers, &tty_drivers);
2938
	mutex_unlock(&tty_mutex);
2939 2940 2941

	if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
		for (i = 0; i < driver->num; i++)
L
Linus Torvalds 已提交
2942 2943 2944
		    tty_register_device(driver, i, NULL);
	}
	proc_tty_register_driver(driver);
A
Alan Cox 已提交
2945
	driver->flags |= TTY_DRIVER_INSTALLED;
L
Linus Torvalds 已提交
2946 2947 2948 2949 2950 2951 2952 2953 2954 2955
	return 0;
}

EXPORT_SYMBOL(tty_register_driver);

/*
 * Called by a tty driver to unregister itself.
 */
int tty_unregister_driver(struct tty_driver *driver)
{
A
Alan Cox 已提交
2956 2957
#if 0
	/* FIXME */
L
Linus Torvalds 已提交
2958 2959
	if (driver->refcount)
		return -EBUSY;
A
Alan Cox 已提交
2960
#endif
L
Linus Torvalds 已提交
2961 2962
	unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
				driver->num);
2963
	mutex_lock(&tty_mutex);
L
Linus Torvalds 已提交
2964
	list_del(&driver->tty_drivers);
2965
	mutex_unlock(&tty_mutex);
L
Linus Torvalds 已提交
2966 2967
	return 0;
}
A
Alan Cox 已提交
2968

L
Linus Torvalds 已提交
2969 2970
EXPORT_SYMBOL(tty_unregister_driver);

2971 2972 2973 2974 2975 2976 2977 2978
dev_t tty_devnum(struct tty_struct *tty)
{
	return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
}
EXPORT_SYMBOL(tty_devnum);

void proc_clear_tty(struct task_struct *p)
{
2979
	unsigned long flags;
A
Alan Cox 已提交
2980
	struct tty_struct *tty;
2981
	spin_lock_irqsave(&p->sighand->siglock, flags);
A
Alan Cox 已提交
2982
	tty = p->signal->tty;
2983
	p->signal->tty = NULL;
2984
	spin_unlock_irqrestore(&p->sighand->siglock, flags);
A
Alan Cox 已提交
2985
	tty_kref_put(tty);
2986 2987
}

A
Alan Cox 已提交
2988 2989
/* Called under the sighand lock */

2990
static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
2991 2992
{
	if (tty) {
A
Alan Cox 已提交
2993 2994 2995
		unsigned long flags;
		/* We should not have a session or pgrp to put here but.... */
		spin_lock_irqsave(&tty->ctrl_lock, flags);
2996 2997
		put_pid(tty->session);
		put_pid(tty->pgrp);
2998
		tty->pgrp = get_pid(task_pgrp(tsk));
A
Alan Cox 已提交
2999 3000
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
		tty->session = get_pid(task_session(tsk));
A
Alan Cox 已提交
3001 3002 3003 3004
		if (tsk->signal->tty) {
			printk(KERN_DEBUG "tty not NULL!!\n");
			tty_kref_put(tsk->signal->tty);
		}
3005
	}
3006
	put_pid(tsk->signal->tty_old_pgrp);
A
Alan Cox 已提交
3007
	tsk->signal->tty = tty_kref_get(tty);
3008
	tsk->signal->tty_old_pgrp = NULL;
3009 3010
}

3011
static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3012 3013
{
	spin_lock_irq(&tsk->sighand->siglock);
3014
	__proc_set_tty(tsk, tty);
3015 3016 3017 3018 3019 3020
	spin_unlock_irq(&tsk->sighand->siglock);
}

struct tty_struct *get_current_tty(void)
{
	struct tty_struct *tty;
A
Alan Cox 已提交
3021 3022 3023
	unsigned long flags;

	spin_lock_irqsave(&current->sighand->siglock, flags);
A
Alan Cox 已提交
3024
	tty = tty_kref_get(current->signal->tty);
A
Alan Cox 已提交
3025
	spin_unlock_irqrestore(&current->sighand->siglock, flags);
3026 3027
	return tty;
}
3028
EXPORT_SYMBOL_GPL(get_current_tty);
L
Linus Torvalds 已提交
3029

3030 3031 3032 3033 3034
void tty_default_fops(struct file_operations *fops)
{
	*fops = tty_fops;
}

L
Linus Torvalds 已提交
3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045
/*
 * 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.
 */
void __init console_init(void)
{
	initcall_t *call;

	/* Setup the default TTY line discipline. */
3046
	tty_ldisc_begin();
L
Linus Torvalds 已提交
3047 3048

	/*
3049
	 * set up the console device so that later boot sequences can
L
Linus Torvalds 已提交
3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060
	 * inform about problems etc..
	 */
	call = __con_initcall_start;
	while (call < __con_initcall_end) {
		(*call)();
		call++;
	}
}

static int __init tty_class_init(void)
{
3061
	tty_class = class_create(THIS_MODULE, "tty");
L
Linus Torvalds 已提交
3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082
	if (IS_ERR(tty_class))
		return PTR_ERR(tty_class);
	return 0;
}

postcore_initcall(tty_class_init);

/* 3/2004 jmc: why do these devices exist? */

static struct cdev tty_cdev, console_cdev;

/*
 * Ok, now we can initialize the rest of the tty devices and can count
 * on memory allocations, interrupts etc..
 */
static int __init tty_init(void)
{
	cdev_init(&tty_cdev, &tty_fops);
	if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
		panic("Couldn't register /dev/tty driver\n");
3083
	device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3084
			      "tty");
L
Linus Torvalds 已提交
3085 3086 3087 3088 3089

	cdev_init(&console_cdev, &console_fops);
	if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
	    register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
		panic("Couldn't register /dev/console driver\n");
3090
	device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3091
			      "console");
L
Linus Torvalds 已提交
3092 3093

#ifdef CONFIG_VT
3094
	vty_init(&console_fops);
L
Linus Torvalds 已提交
3095 3096 3097 3098
#endif
	return 0;
}
module_init(tty_init);