diff options
Diffstat (limited to 'drivers/tty/tty_ioctl.c')
| -rw-r--r-- | drivers/tty/tty_ioctl.c | 908 |
1 files changed, 908 insertions, 0 deletions
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c new file mode 100644 index 000000000..12a30329a --- /dev/null +++ b/drivers/tty/tty_ioctl.c @@ -0,0 +1,908 @@ +// 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 "tty.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); + + if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) { +retry_write_wait: + retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty)); + if (retval < 0) + return retval; + + if (tty_write_lock(tty, false) < 0) + goto retry_write_wait; + + /* Racing writer? */ + if (tty_chars_in_buffer(tty)) { + tty_write_unlock(tty); + goto retry_write_wait; + } + + 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->ops->wait_until_sent) { + tty->ops->wait_until_sent(tty, 0); + if (signal_pending(current)) { + tty_write_unlock(tty); + return -ERESTARTSYS; + } + } + + tty_set_termios(tty, &tmp_termios); + + tty_write_unlock(tty); + } else { + 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); |