Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *
 * 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).
 */
 
#include <linux/types.h>
#include <linux/termios.h>
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/tty.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/compat.h>
 
#include <asm/io.h>
#include <linux/uaccess.h>
 
#undef TTY_DEBUG_WAIT_UNTIL_SENT
 
#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
# define tty_debug_wait_until_sent(tty, f, args...)    tty_debug(tty, f, ##args)
#else
# define tty_debug_wait_until_sent(tty, f, args...)    do {} while (0)
#endif
 
#undef	DEBUG
 
/*
 * Internal flag options for termios setting behavior
 */
#define TERMIOS_FLUSH	1
#define TERMIOS_WAIT	2
#define TERMIOS_TERMIO	4
#define TERMIOS_OLD	8
 
 
/**
 *	tty_chars_in_buffer	-	characters pending
 *	@tty: terminal
 *
 *	Return the number of bytes of data in the device private
 *	output queue. If no private method is supplied there is assumed
 *	to be no queue on the device.
 */
 
int tty_chars_in_buffer(struct tty_struct *tty)
{
<------>if (tty->ops->chars_in_buffer)
<------><------>return tty->ops->chars_in_buffer(tty);
<------>else
<------><------>return 0;
}
EXPORT_SYMBOL(tty_chars_in_buffer);
 
/**
 *	tty_write_room		-	write queue space
 *	@tty: terminal
 *
 *	Return the number of bytes that can be queued to this device
 *	at the present time. The result should be treated as a guarantee
 *	and the driver cannot offer a value it later shrinks by more than
 *	the number of bytes written. If no method is provided 2K is always
 *	returned and data may be lost as there will be no flow control.
 */
 
int tty_write_room(struct tty_struct *tty)
{
<------>if (tty->ops->write_room)
<------><------>return tty->ops->write_room(tty);
<------>return 2048;
}
EXPORT_SYMBOL(tty_write_room);
 
/**
 *	tty_driver_flush_buffer	-	discard internal buffer
 *	@tty: terminal
 *
 *	Discard the internal output buffer for this device. If no method
 *	is provided then either the buffer cannot be hardware flushed or
 *	there is no buffer driver side.
 */
void tty_driver_flush_buffer(struct tty_struct *tty)
{
<------>if (tty->ops->flush_buffer)
<------><------>tty->ops->flush_buffer(tty);
}
EXPORT_SYMBOL(tty_driver_flush_buffer);
 
/**
 *	tty_throttle		-	flow control
 *	@tty: terminal
 *
 *	Indicate that a tty should stop transmitting data down the stack.
 *	Takes the termios rwsem to protect against parallel throttle/unthrottle
 *	and also to ensure the driver can consistently reference its own
 *	termios data at this point when implementing software flow control.
 */
 
void tty_throttle(struct tty_struct *tty)
{
<------>down_write(&tty->termios_rwsem);
<------>/* check TTY_THROTTLED first so it indicates our state */
<------>if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
<------>    tty->ops->throttle)
<------><------>tty->ops->throttle(tty);
<------>tty->flow_change = 0;
<------>up_write(&tty->termios_rwsem);
}
EXPORT_SYMBOL(tty_throttle);
 
/**
 *	tty_unthrottle		-	flow control
 *	@tty: terminal
 *
 *	Indicate that a tty may continue transmitting data down the stack.
 *	Takes the termios rwsem to protect against parallel throttle/unthrottle
 *	and also to ensure the driver can consistently reference its own
 *	termios data at this point when implementing software flow control.
 *
 *	Drivers should however remember that the stack can issue a throttle,
 *	then change flow control method, then unthrottle.
 */
 
void tty_unthrottle(struct tty_struct *tty)
{
<------>down_write(&tty->termios_rwsem);
<------>if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
<------>    tty->ops->unthrottle)
<------><------>tty->ops->unthrottle(tty);
<------>tty->flow_change = 0;
<------>up_write(&tty->termios_rwsem);
}
EXPORT_SYMBOL(tty_unthrottle);
 
/**
 *	tty_throttle_safe	-	flow control
 *	@tty: terminal
 *
 *	Similar to tty_throttle() but will only attempt throttle
 *	if tty->flow_change is TTY_THROTTLE_SAFE. Prevents an accidental
 *	throttle due to race conditions when throttling is conditional
 *	on factors evaluated prior to throttling.
 *
 *	Returns 0 if tty is throttled (or was already throttled)
 */
 
int tty_throttle_safe(struct tty_struct *tty)
{
<------>int ret = 0;
 
<------>mutex_lock(&tty->throttle_mutex);
<------>if (!tty_throttled(tty)) {
<------><------>if (tty->flow_change != TTY_THROTTLE_SAFE)
<------><------><------>ret = 1;
<------><------>else {
<------><------><------>set_bit(TTY_THROTTLED, &tty->flags);
<------><------><------>if (tty->ops->throttle)
<------><------><------><------>tty->ops->throttle(tty);
<------><------>}
<------>}
<------>mutex_unlock(&tty->throttle_mutex);
 
<------>return ret;
}
 
/**
 *	tty_unthrottle_safe	-	flow control
 *	@tty: terminal
 *
 *	Similar to tty_unthrottle() but will only attempt unthrottle
 *	if tty->flow_change is TTY_UNTHROTTLE_SAFE. Prevents an accidental
 *	unthrottle due to race conditions when unthrottling is conditional
 *	on factors evaluated prior to unthrottling.
 *
 *	Returns 0 if tty is unthrottled (or was already unthrottled)
 */
 
int tty_unthrottle_safe(struct tty_struct *tty)
{
<------>int ret = 0;
 
<------>mutex_lock(&tty->throttle_mutex);
<------>if (tty_throttled(tty)) {
<------><------>if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
<------><------><------>ret = 1;
<------><------>else {
<------><------><------>clear_bit(TTY_THROTTLED, &tty->flags);
<------><------><------>if (tty->ops->unthrottle)
<------><------><------><------>tty->ops->unthrottle(tty);
<------><------>}
<------>}
<------>mutex_unlock(&tty->throttle_mutex);
 
<------>return ret;
}
 
/**
 *	tty_wait_until_sent	-	wait for I/O to finish
 *	@tty: tty we are waiting for
 *	@timeout: how long we will wait
 *
 *	Wait for characters pending in a tty driver to hit the wire, or
 *	for a timeout to occur (eg due to flow control)
 *
 *	Locking: none
 */
 
void tty_wait_until_sent(struct tty_struct *tty, long timeout)
{
<------>tty_debug_wait_until_sent(tty, "wait until sent, timeout=%ld\n", timeout);
 
<------>if (!timeout)
<------><------>timeout = MAX_SCHEDULE_TIMEOUT;
 
<------>timeout = wait_event_interruptible_timeout(tty->write_wait,
<------><------><------>!tty_chars_in_buffer(tty), timeout);
<------>if (timeout <= 0)
<------><------>return;
 
<------>if (timeout == MAX_SCHEDULE_TIMEOUT)
<------><------>timeout = 0;
 
<------>if (tty->ops->wait_until_sent)
<------><------>tty->ops->wait_until_sent(tty, timeout);
}
EXPORT_SYMBOL(tty_wait_until_sent);
 
 
/*
 *		Termios Helper Methods
 */
 
static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
{
<------>struct ktermios *termios = &tty->termios;
<------>struct ktermios *locked  = &tty->termios_locked;
<------>int	i;
 
#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
 
<------>NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
<------>NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
<------>NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
<------>NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
<------>termios->c_line = locked->c_line ? old->c_line : termios->c_line;
<------>for (i = 0; i < NCCS; i++)
<------><------>termios->c_cc[i] = locked->c_cc[i] ?
<------><------><------>old->c_cc[i] : termios->c_cc[i];
<------>/* FIXME: What should we do for i/ospeed */
}
 
/**
 *	tty_termios_copy_hw	-	copy hardware settings
 *	@new: New termios
 *	@old: Old termios
 *
 *	Propagate the hardware specific terminal setting bits from
 *	the old termios structure to the new one. This is used in cases
 *	where the hardware does not support reconfiguration or as a helper
 *	in some cases where only minimal reconfiguration is supported
 */
 
void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
{
<------>/* The bits a dumb device handles in software. Smart devices need
<------>   to always provide a set_termios method */
<------>new->c_cflag &= HUPCL | CREAD | CLOCAL;
<------>new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
<------>new->c_ispeed = old->c_ispeed;
<------>new->c_ospeed = old->c_ospeed;
}
EXPORT_SYMBOL(tty_termios_copy_hw);
 
/**
 *	tty_termios_hw_change	-	check for setting change
 *	@a: termios
 *	@b: termios to compare
 *
 *	Check if any of the bits that affect a dumb device have changed
 *	between the two termios structures, or a speed change is needed.
 */
 
int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
{
<------>if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
<------><------>return 1;
<------>if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
<------><------>return 1;
<------>return 0;
}
EXPORT_SYMBOL(tty_termios_hw_change);
 
/**
 *	tty_set_termios		-	update termios values
 *	@tty: tty to update
 *	@new_termios: desired new value
 *
 *	Perform updates to the termios values set on this terminal.
 *	A master pty's termios should never be set.
 *
 *	Locking: termios_rwsem
 */
 
int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
{
<------>struct ktermios old_termios;
<------>struct tty_ldisc *ld;
 
<------>WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
<------><------>tty->driver->subtype == PTY_TYPE_MASTER);
<------>/*
<------> *	Perform the actual termios internal changes under lock.
<------> */
 
 
<------>/* FIXME: we need to decide on some locking/ordering semantics
<------>   for the set_termios notification eventually */
<------>down_write(&tty->termios_rwsem);
<------>old_termios = tty->termios;
<------>tty->termios = *new_termios;
<------>unset_locked_termios(tty, &old_termios);
 
<------>if (tty->ops->set_termios)
<------><------>tty->ops->set_termios(tty, &old_termios);
<------>else
<------><------>tty_termios_copy_hw(&tty->termios, &old_termios);
 
<------>ld = tty_ldisc_ref(tty);
<------>if (ld != NULL) {
<------><------>if (ld->ops->set_termios)
<------><------><------>ld->ops->set_termios(tty, &old_termios);
<------><------>tty_ldisc_deref(ld);
<------>}
<------>up_write(&tty->termios_rwsem);
<------>return 0;
}
EXPORT_SYMBOL_GPL(tty_set_termios);
 
/**
 *	set_termios		-	set termios values for a tty
 *	@tty: terminal device
 *	@arg: user data
 *	@opt: option information
 *
 *	Helper function to prepare termios data and run necessary other
 *	functions before using tty_set_termios to do the actual changes.
 *
 *	Locking:
 *		Called functions take ldisc and termios_rwsem locks
 */
 
static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
{
<------>struct ktermios tmp_termios;
<------>struct tty_ldisc *ld;
<------>int retval = tty_check_change(tty);
 
<------>if (retval)
<------><------>return retval;
 
<------>down_read(&tty->termios_rwsem);
<------>tmp_termios = tty->termios;
<------>up_read(&tty->termios_rwsem);
 
<------>if (opt & TERMIOS_TERMIO) {
<------><------>if (user_termio_to_kernel_termios(&tmp_termios,
<------><------><------><------><------><------>(struct termio __user *)arg))
<------><------><------>return -EFAULT;
#ifdef TCGETS2
<------>} else if (opt & TERMIOS_OLD) {
<------><------>if (user_termios_to_kernel_termios_1(&tmp_termios,
<------><------><------><------><------><------>(struct termios __user *)arg))
<------><------><------>return -EFAULT;
<------>} else {
<------><------>if (user_termios_to_kernel_termios(&tmp_termios,
<------><------><------><------><------><------>(struct termios2 __user *)arg))
<------><------><------>return -EFAULT;
<------>}
#else
<------>} else if (user_termios_to_kernel_termios(&tmp_termios,
<------><------><------><------><------>(struct termios __user *)arg))
<------><------>return -EFAULT;
#endif
 
<------>/* If old style Bfoo values are used then load c_ispeed/c_ospeed
<------> * with the real speed so its unconditionally usable */
<------>tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
<------>tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
 
<------>ld = tty_ldisc_ref(tty);
 
<------>if (ld != NULL) {
<------><------>if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
<------><------><------>ld->ops->flush_buffer(tty);
<------><------>tty_ldisc_deref(ld);
<------>}
 
<------>if (opt & TERMIOS_WAIT) {
<------><------>tty_wait_until_sent(tty, 0);
<------><------>if (signal_pending(current))
<------><------><------>return -ERESTARTSYS;
<------>}
 
<------>tty_set_termios(tty, &tmp_termios);
 
<------>/* FIXME: Arguably if tmp_termios == tty->termios AND the
<------>   actual requested termios was not tmp_termios then we may
<------>   want to return an error as no user requested change has
<------>   succeeded */
<------>return 0;
}
 
static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
{
<------>down_read(&tty->termios_rwsem);
<------>*kterm = tty->termios;
<------>up_read(&tty->termios_rwsem);
}
 
static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
{
<------>down_read(&tty->termios_rwsem);
<------>*kterm = tty->termios_locked;
<------>up_read(&tty->termios_rwsem);
}
 
static int get_termio(struct tty_struct *tty, struct termio __user *termio)
{
<------>struct ktermios kterm;
<------>copy_termios(tty, &kterm);
<------>if (kernel_termios_to_user_termio(termio, &kterm))
<------><------>return -EFAULT;
<------>return 0;
}
 
#ifdef TIOCGETP
/*
 * These are deprecated, but there is limited support..
 *
 * The "sg_flags" translation is a joke..
 */
static int get_sgflags(struct tty_struct *tty)
{
<------>int flags = 0;
 
<------>if (!L_ICANON(tty)) {
<------><------>if (L_ISIG(tty))
<------><------><------>flags |= 0x02;		/* cbreak */
<------><------>else
<------><------><------>flags |= 0x20;		/* raw */
<------>}
<------>if (L_ECHO(tty))
<------><------>flags |= 0x08;			/* echo */
<------>if (O_OPOST(tty))
<------><------>if (O_ONLCR(tty))
<------><------><------>flags |= 0x10;		/* crmod */
<------>return flags;
}
 
static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
{
<------>struct sgttyb tmp;
 
<------>down_read(&tty->termios_rwsem);
<------>tmp.sg_ispeed = tty->termios.c_ispeed;
<------>tmp.sg_ospeed = tty->termios.c_ospeed;
<------>tmp.sg_erase = tty->termios.c_cc[VERASE];
<------>tmp.sg_kill = tty->termios.c_cc[VKILL];
<------>tmp.sg_flags = get_sgflags(tty);
<------>up_read(&tty->termios_rwsem);
 
<------>return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
 
static void set_sgflags(struct ktermios *termios, int flags)
{
<------>termios->c_iflag = ICRNL | IXON;
<------>termios->c_oflag = 0;
<------>termios->c_lflag = ISIG | ICANON;
<------>if (flags & 0x02) {	/* cbreak */
<------><------>termios->c_iflag = 0;
<------><------>termios->c_lflag &= ~ICANON;
<------>}
<------>if (flags & 0x08) {		/* echo */
<------><------>termios->c_lflag |= ECHO | ECHOE | ECHOK |
<------><------><------><------>    ECHOCTL | ECHOKE | IEXTEN;
<------>}
<------>if (flags & 0x10) {		/* crmod */
<------><------>termios->c_oflag |= OPOST | ONLCR;
<------>}
<------>if (flags & 0x20) {	/* raw */
<------><------>termios->c_iflag = 0;
<------><------>termios->c_lflag &= ~(ISIG | ICANON);
<------>}
<------>if (!(termios->c_lflag & ICANON)) {
<------><------>termios->c_cc[VMIN] = 1;
<------><------>termios->c_cc[VTIME] = 0;
<------>}
}
 
/**
 *	set_sgttyb		-	set legacy terminal values
 *	@tty: tty structure
 *	@sgttyb: pointer to old style terminal structure
 *
 *	Updates a terminal from the legacy BSD style terminal information
 *	structure.
 *
 *	Locking: termios_rwsem
 */
 
static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
{
<------>int retval;
<------>struct sgttyb tmp;
<------>struct ktermios termios;
 
<------>retval = tty_check_change(tty);
<------>if (retval)
<------><------>return retval;
 
<------>if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
<------><------>return -EFAULT;
 
<------>down_write(&tty->termios_rwsem);
<------>termios = tty->termios;
<------>termios.c_cc[VERASE] = tmp.sg_erase;
<------>termios.c_cc[VKILL] = tmp.sg_kill;
<------>set_sgflags(&termios, tmp.sg_flags);
<------>/* Try and encode into Bfoo format */
#ifdef BOTHER
<------>tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
<------><------><------><------><------><------>termios.c_ospeed);
#endif
<------>up_write(&tty->termios_rwsem);
<------>tty_set_termios(tty, &termios);
<------>return 0;
}
#endif
 
#ifdef TIOCGETC
static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
{
<------>struct tchars tmp;
 
<------>down_read(&tty->termios_rwsem);
<------>tmp.t_intrc = tty->termios.c_cc[VINTR];
<------>tmp.t_quitc = tty->termios.c_cc[VQUIT];
<------>tmp.t_startc = tty->termios.c_cc[VSTART];
<------>tmp.t_stopc = tty->termios.c_cc[VSTOP];
<------>tmp.t_eofc = tty->termios.c_cc[VEOF];
<------>tmp.t_brkc = tty->termios.c_cc[VEOL2];	/* what is brkc anyway? */
<------>up_read(&tty->termios_rwsem);
<------>return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
 
static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
{
<------>struct tchars tmp;
 
<------>if (copy_from_user(&tmp, tchars, sizeof(tmp)))
<------><------>return -EFAULT;
<------>down_write(&tty->termios_rwsem);
<------>tty->termios.c_cc[VINTR] = tmp.t_intrc;
<------>tty->termios.c_cc[VQUIT] = tmp.t_quitc;
<------>tty->termios.c_cc[VSTART] = tmp.t_startc;
<------>tty->termios.c_cc[VSTOP] = tmp.t_stopc;
<------>tty->termios.c_cc[VEOF] = tmp.t_eofc;
<------>tty->termios.c_cc[VEOL2] = tmp.t_brkc;	/* what is brkc anyway? */
<------>up_write(&tty->termios_rwsem);
<------>return 0;
}
#endif
 
#ifdef TIOCGLTC
static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
{
<------>struct ltchars tmp;
 
<------>down_read(&tty->termios_rwsem);
<------>tmp.t_suspc = tty->termios.c_cc[VSUSP];
<------>/* what is dsuspc anyway? */
<------>tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
<------>tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
<------>/* what is flushc anyway? */
<------>tmp.t_flushc = tty->termios.c_cc[VEOL2];
<------>tmp.t_werasc = tty->termios.c_cc[VWERASE];
<------>tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
<------>up_read(&tty->termios_rwsem);
<------>return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}
 
static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
{
<------>struct ltchars tmp;
 
<------>if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
<------><------>return -EFAULT;
 
<------>down_write(&tty->termios_rwsem);
<------>tty->termios.c_cc[VSUSP] = tmp.t_suspc;
<------>/* what is dsuspc anyway? */
<------>tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
<------>tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
<------>/* what is flushc anyway? */
<------>tty->termios.c_cc[VEOL2] = tmp.t_flushc;
<------>tty->termios.c_cc[VWERASE] = tmp.t_werasc;
<------>tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
<------>up_write(&tty->termios_rwsem);
<------>return 0;
}
#endif
 
/**
 *	tty_change_softcar	-	carrier change ioctl helper
 *	@tty: tty to update
 *	@arg: enable/disable CLOCAL
 *
 *	Perform a change to the CLOCAL state and call into the driver
 *	layer to make it visible. All done with the termios rwsem
 */
 
static int tty_change_softcar(struct tty_struct *tty, int arg)
{
<------>int ret = 0;
<------>int bit = arg ? CLOCAL : 0;
<------>struct ktermios old;
 
<------>down_write(&tty->termios_rwsem);
<------>old = tty->termios;
<------>tty->termios.c_cflag &= ~CLOCAL;
<------>tty->termios.c_cflag |= bit;
<------>if (tty->ops->set_termios)
<------><------>tty->ops->set_termios(tty, &old);
<------>if (C_CLOCAL(tty) != bit)
<------><------>ret = -EINVAL;
<------>up_write(&tty->termios_rwsem);
<------>return ret;
}
 
/**
 *	tty_mode_ioctl		-	mode related ioctls
 *	@tty: tty for the ioctl
 *	@file: file pointer for the tty
 *	@cmd: command
 *	@arg: ioctl argument
 *
 *	Perform non line discipline specific mode control ioctls. This
 *	is designed to be called by line disciplines to ensure they provide
 *	consistent mode setting.
 */
 
int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
<------><------><------>unsigned int cmd, unsigned long arg)
{
<------>struct tty_struct *real_tty;
<------>void __user *p = (void __user *)arg;
<------>int ret = 0;
<------>struct ktermios kterm;
 
<------>BUG_ON(file == NULL);
 
<------>if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
<------>    tty->driver->subtype == PTY_TYPE_MASTER)
<------><------>real_tty = tty->link;
<------>else
<------><------>real_tty = tty;
 
<------>switch (cmd) {
#ifdef TIOCGETP
<------>case TIOCGETP:
<------><------>return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
<------>case TIOCSETP:
<------>case TIOCSETN:
<------><------>return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
#endif
#ifdef TIOCGETC
<------>case TIOCGETC:
<------><------>return get_tchars(real_tty, p);
<------>case TIOCSETC:
<------><------>return set_tchars(real_tty, p);
#endif
#ifdef TIOCGLTC
<------>case TIOCGLTC:
<------><------>return get_ltchars(real_tty, p);
<------>case TIOCSLTC:
<------><------>return set_ltchars(real_tty, p);
#endif
<------>case TCSETSF:
<------><------>return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
<------>case TCSETSW:
<------><------>return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
<------>case TCSETS:
<------><------>return set_termios(real_tty, p, TERMIOS_OLD);
#ifndef TCGETS2
<------>case TCGETS:
<------><------>copy_termios(real_tty, &kterm);
<------><------>if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
<------><------><------>ret = -EFAULT;
<------><------>return ret;
#else
<------>case TCGETS:
<------><------>copy_termios(real_tty, &kterm);
<------><------>if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
<------><------><------>ret = -EFAULT;
<------><------>return ret;
<------>case TCGETS2:
<------><------>copy_termios(real_tty, &kterm);
<------><------>if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
<------><------><------>ret = -EFAULT;
<------><------>return ret;
<------>case TCSETSF2:
<------><------>return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT);
<------>case TCSETSW2:
<------><------>return set_termios(real_tty, p, TERMIOS_WAIT);
<------>case TCSETS2:
<------><------>return set_termios(real_tty, p, 0);
#endif
<------>case TCGETA:
<------><------>return get_termio(real_tty, p);
<------>case TCSETAF:
<------><------>return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
<------>case TCSETAW:
<------><------>return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
<------>case TCSETA:
<------><------>return set_termios(real_tty, p, TERMIOS_TERMIO);
#ifndef TCGETS2
<------>case TIOCGLCKTRMIOS:
<------><------>copy_termios_locked(real_tty, &kterm);
<------><------>if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
<------><------><------>ret = -EFAULT;
<------><------>return ret;
<------>case TIOCSLCKTRMIOS:
<------><------>if (!capable(CAP_SYS_ADMIN))
<------><------><------>return -EPERM;
<------><------>copy_termios_locked(real_tty, &kterm);
<------><------>if (user_termios_to_kernel_termios(&kterm,
<------><------><------><------><------>       (struct termios __user *) arg))
<------><------><------>return -EFAULT;
<------><------>down_write(&real_tty->termios_rwsem);
<------><------>real_tty->termios_locked = kterm;
<------><------>up_write(&real_tty->termios_rwsem);
<------><------>return 0;
#else
<------>case TIOCGLCKTRMIOS:
<------><------>copy_termios_locked(real_tty, &kterm);
<------><------>if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
<------><------><------>ret = -EFAULT;
<------><------>return ret;
<------>case TIOCSLCKTRMIOS:
<------><------>if (!capable(CAP_SYS_ADMIN))
<------><------><------>return -EPERM;
<------><------>copy_termios_locked(real_tty, &kterm);
<------><------>if (user_termios_to_kernel_termios_1(&kterm,
<------><------><------><------><------>       (struct termios __user *) arg))
<------><------><------>return -EFAULT;
<------><------>down_write(&real_tty->termios_rwsem);
<------><------>real_tty->termios_locked = kterm;
<------><------>up_write(&real_tty->termios_rwsem);
<------><------>return ret;
#endif
#ifdef TCGETX
<------>case TCGETX:
<------>case TCSETX:
<------>case TCSETXW:
<------>case TCSETXF:
<------><------>return -ENOTTY;
#endif
<------>case TIOCGSOFTCAR:
<------><------>copy_termios(real_tty, &kterm);
<------><------>ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
<------><------><------><------><------><------>(int __user *)arg);
<------><------>return ret;
<------>case TIOCSSOFTCAR:
<------><------>if (get_user(arg, (unsigned int __user *) arg))
<------><------><------>return -EFAULT;
<------><------>return tty_change_softcar(real_tty, arg);
<------>default:
<------><------>return -ENOIOCTLCMD;
<------>}
}
EXPORT_SYMBOL_GPL(tty_mode_ioctl);
 
 
/* Caller guarantees ldisc reference is held */
static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
{
<------>struct tty_ldisc *ld = tty->ldisc;
 
<------>switch (arg) {
<------>case TCIFLUSH:
<------><------>if (ld && ld->ops->flush_buffer) {
<------><------><------>ld->ops->flush_buffer(tty);
<------><------><------>tty_unthrottle(tty);
<------><------>}
<------><------>break;
<------>case TCIOFLUSH:
<------><------>if (ld && ld->ops->flush_buffer) {
<------><------><------>ld->ops->flush_buffer(tty);
<------><------><------>tty_unthrottle(tty);
<------><------>}
<------><------>fallthrough;
<------>case TCOFLUSH:
<------><------>tty_driver_flush_buffer(tty);
<------><------>break;
<------>default:
<------><------>return -EINVAL;
<------>}
<------>return 0;
}
 
int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
{
<------>struct tty_ldisc *ld;
<------>int retval = tty_check_change(tty);
<------>if (retval)
<------><------>return retval;
 
<------>ld = tty_ldisc_ref_wait(tty);
<------>retval = __tty_perform_flush(tty, arg);
<------>if (ld)
<------><------>tty_ldisc_deref(ld);
<------>return retval;
}
EXPORT_SYMBOL_GPL(tty_perform_flush);
 
int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
<------><------>       unsigned int cmd, unsigned long arg)
{
<------>int retval;
 
<------>switch (cmd) {
<------>case TCXONC:
<------><------>retval = tty_check_change(tty);
<------><------>if (retval)
<------><------><------>return retval;
<------><------>switch (arg) {
<------><------>case TCOOFF:
<------><------><------>spin_lock_irq(&tty->flow_lock);
<------><------><------>if (!tty->flow_stopped) {
<------><------><------><------>tty->flow_stopped = 1;
<------><------><------><------>__stop_tty(tty);
<------><------><------>}
<------><------><------>spin_unlock_irq(&tty->flow_lock);
<------><------><------>break;
<------><------>case TCOON:
<------><------><------>spin_lock_irq(&tty->flow_lock);
<------><------><------>if (tty->flow_stopped) {
<------><------><------><------>tty->flow_stopped = 0;
<------><------><------><------>__start_tty(tty);
<------><------><------>}
<------><------><------>spin_unlock_irq(&tty->flow_lock);
<------><------><------>break;
<------><------>case TCIOFF:
<------><------><------>if (STOP_CHAR(tty) != __DISABLED_CHAR)
<------><------><------><------>retval = tty_send_xchar(tty, STOP_CHAR(tty));
<------><------><------>break;
<------><------>case TCION:
<------><------><------>if (START_CHAR(tty) != __DISABLED_CHAR)
<------><------><------><------>retval = tty_send_xchar(tty, START_CHAR(tty));
<------><------><------>break;
<------><------>default:
<------><------><------>return -EINVAL;
<------><------>}
<------><------>return retval;
<------>case TCFLSH:
<------><------>retval = tty_check_change(tty);
<------><------>if (retval)
<------><------><------>return retval;
<------><------>return __tty_perform_flush(tty, arg);
<------>default:
<------><------>/* Try the mode commands */
<------><------>return tty_mode_ioctl(tty, file, cmd, arg);
<------>}
}
EXPORT_SYMBOL(n_tty_ioctl_helper);