2 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
4 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
5 * which can be dynamically activated and de-activated by the line
6 * discipline handling modules (like SLIP).
9 #include <linux/types.h>
10 #include <linux/termios.h>
11 #include <linux/errno.h>
12 #include <linux/sched/signal.h>
13 #include <linux/kernel.h>
14 #include <linux/major.h>
15 #include <linux/tty.h>
16 #include <linux/fcntl.h>
17 #include <linux/string.h>
19 #include <linux/module.h>
20 #include <linux/bitops.h>
21 #include <linux/mutex.h>
22 #include <linux/compat.h>
25 #include <linux/uaccess.h>
27 #undef TTY_DEBUG_WAIT_UNTIL_SENT
29 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
30 # define tty_debug_wait_until_sent(tty, f, args...) tty_debug(tty, f, ##args)
32 # define tty_debug_wait_until_sent(tty, f, args...) do {} while (0)
38 * Internal flag options for termios setting behavior
40 #define TERMIOS_FLUSH 1
41 #define TERMIOS_WAIT 2
42 #define TERMIOS_TERMIO 4
47 * tty_chars_in_buffer - characters pending
50 * Return the number of bytes of data in the device private
51 * output queue. If no private method is supplied there is assumed
52 * to be no queue on the device.
55 int tty_chars_in_buffer(struct tty_struct *tty)
57 if (tty->ops->chars_in_buffer)
58 return tty->ops->chars_in_buffer(tty);
62 EXPORT_SYMBOL(tty_chars_in_buffer);
65 * tty_write_room - write queue space
68 * Return the number of bytes that can be queued to this device
69 * at the present time. The result should be treated as a guarantee
70 * and the driver cannot offer a value it later shrinks by more than
71 * the number of bytes written. If no method is provided 2K is always
72 * returned and data may be lost as there will be no flow control.
75 int tty_write_room(struct tty_struct *tty)
77 if (tty->ops->write_room)
78 return tty->ops->write_room(tty);
81 EXPORT_SYMBOL(tty_write_room);
84 * tty_driver_flush_buffer - discard internal buffer
87 * Discard the internal output buffer for this device. If no method
88 * is provided then either the buffer cannot be hardware flushed or
89 * there is no buffer driver side.
91 void tty_driver_flush_buffer(struct tty_struct *tty)
93 if (tty->ops->flush_buffer)
94 tty->ops->flush_buffer(tty);
96 EXPORT_SYMBOL(tty_driver_flush_buffer);
99 * tty_throttle - flow control
102 * Indicate that a tty should stop transmitting data down the stack.
103 * Takes the termios rwsem to protect against parallel throttle/unthrottle
104 * and also to ensure the driver can consistently reference its own
105 * termios data at this point when implementing software flow control.
108 void tty_throttle(struct tty_struct *tty)
110 down_write(&tty->termios_rwsem);
111 /* check TTY_THROTTLED first so it indicates our state */
112 if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
114 tty->ops->throttle(tty);
115 tty->flow_change = 0;
116 up_write(&tty->termios_rwsem);
118 EXPORT_SYMBOL(tty_throttle);
121 * tty_unthrottle - flow control
124 * Indicate that a tty may continue transmitting data down the stack.
125 * Takes the termios rwsem to protect against parallel throttle/unthrottle
126 * and also to ensure the driver can consistently reference its own
127 * termios data at this point when implementing software flow control.
129 * Drivers should however remember that the stack can issue a throttle,
130 * then change flow control method, then unthrottle.
133 void tty_unthrottle(struct tty_struct *tty)
135 down_write(&tty->termios_rwsem);
136 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
137 tty->ops->unthrottle)
138 tty->ops->unthrottle(tty);
139 tty->flow_change = 0;
140 up_write(&tty->termios_rwsem);
142 EXPORT_SYMBOL(tty_unthrottle);
145 * tty_throttle_safe - flow control
148 * Similar to tty_throttle() but will only attempt throttle
149 * if tty->flow_change is TTY_THROTTLE_SAFE. Prevents an accidental
150 * throttle due to race conditions when throttling is conditional
151 * on factors evaluated prior to throttling.
153 * Returns 0 if tty is throttled (or was already throttled)
156 int tty_throttle_safe(struct tty_struct *tty)
160 mutex_lock(&tty->throttle_mutex);
161 if (!tty_throttled(tty)) {
162 if (tty->flow_change != TTY_THROTTLE_SAFE)
165 set_bit(TTY_THROTTLED, &tty->flags);
166 if (tty->ops->throttle)
167 tty->ops->throttle(tty);
170 mutex_unlock(&tty->throttle_mutex);
176 * tty_unthrottle_safe - flow control
179 * Similar to tty_unthrottle() but will only attempt unthrottle
180 * if tty->flow_change is TTY_UNTHROTTLE_SAFE. Prevents an accidental
181 * unthrottle due to race conditions when unthrottling is conditional
182 * on factors evaluated prior to unthrottling.
184 * Returns 0 if tty is unthrottled (or was already unthrottled)
187 int tty_unthrottle_safe(struct tty_struct *tty)
191 mutex_lock(&tty->throttle_mutex);
192 if (tty_throttled(tty)) {
193 if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
196 clear_bit(TTY_THROTTLED, &tty->flags);
197 if (tty->ops->unthrottle)
198 tty->ops->unthrottle(tty);
201 mutex_unlock(&tty->throttle_mutex);
207 * tty_wait_until_sent - wait for I/O to finish
208 * @tty: tty we are waiting for
209 * @timeout: how long we will wait
211 * Wait for characters pending in a tty driver to hit the wire, or
212 * for a timeout to occur (eg due to flow control)
217 void tty_wait_until_sent(struct tty_struct *tty, long timeout)
219 tty_debug_wait_until_sent(tty, "wait until sent, timeout=%ld\n", timeout);
222 timeout = MAX_SCHEDULE_TIMEOUT;
224 timeout = wait_event_interruptible_timeout(tty->write_wait,
225 !tty_chars_in_buffer(tty), timeout);
229 if (timeout == MAX_SCHEDULE_TIMEOUT)
232 if (tty->ops->wait_until_sent)
233 tty->ops->wait_until_sent(tty, timeout);
235 EXPORT_SYMBOL(tty_wait_until_sent);
239 * Termios Helper Methods
242 static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
244 struct ktermios *termios = &tty->termios;
245 struct ktermios *locked = &tty->termios_locked;
248 #define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
250 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
251 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
252 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
253 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
254 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
255 for (i = 0; i < NCCS; i++)
256 termios->c_cc[i] = locked->c_cc[i] ?
257 old->c_cc[i] : termios->c_cc[i];
258 /* FIXME: What should we do for i/ospeed */
262 * tty_termios_copy_hw - copy hardware settings
266 * Propagate the hardware specific terminal setting bits from
267 * the old termios structure to the new one. This is used in cases
268 * where the hardware does not support reconfiguration or as a helper
269 * in some cases where only minimal reconfiguration is supported
272 void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
274 /* The bits a dumb device handles in software. Smart devices need
275 to always provide a set_termios method */
276 new->c_cflag &= HUPCL | CREAD | CLOCAL;
277 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
278 new->c_ispeed = old->c_ispeed;
279 new->c_ospeed = old->c_ospeed;
281 EXPORT_SYMBOL(tty_termios_copy_hw);
284 * tty_termios_hw_change - check for setting change
286 * @b: termios to compare
288 * Check if any of the bits that affect a dumb device have changed
289 * between the two termios structures, or a speed change is needed.
292 int tty_termios_hw_change(struct ktermios *a, struct ktermios *b)
294 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
296 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
300 EXPORT_SYMBOL(tty_termios_hw_change);
303 * tty_set_termios - update termios values
304 * @tty: tty to update
305 * @new_termios: desired new value
307 * Perform updates to the termios values set on this terminal.
308 * A master pty's termios should never be set.
310 * Locking: termios_rwsem
313 int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
315 struct ktermios old_termios;
316 struct tty_ldisc *ld;
318 WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
319 tty->driver->subtype == PTY_TYPE_MASTER);
321 * Perform the actual termios internal changes under lock.
325 /* FIXME: we need to decide on some locking/ordering semantics
326 for the set_termios notification eventually */
327 down_write(&tty->termios_rwsem);
328 old_termios = tty->termios;
329 tty->termios = *new_termios;
330 unset_locked_termios(tty, &old_termios);
332 if (tty->ops->set_termios)
333 tty->ops->set_termios(tty, &old_termios);
335 tty_termios_copy_hw(&tty->termios, &old_termios);
337 ld = tty_ldisc_ref(tty);
339 if (ld->ops->set_termios)
340 ld->ops->set_termios(tty, &old_termios);
343 up_write(&tty->termios_rwsem);
346 EXPORT_SYMBOL_GPL(tty_set_termios);
349 * set_termios - set termios values for a tty
350 * @tty: terminal device
352 * @opt: option information
354 * Helper function to prepare termios data and run necessary other
355 * functions before using tty_set_termios to do the actual changes.
358 * Called functions take ldisc and termios_rwsem locks
361 static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
363 struct ktermios tmp_termios;
364 struct tty_ldisc *ld;
365 int retval = tty_check_change(tty);
370 down_read(&tty->termios_rwsem);
371 tmp_termios = tty->termios;
372 up_read(&tty->termios_rwsem);
374 if (opt & TERMIOS_TERMIO) {
375 if (user_termio_to_kernel_termios(&tmp_termios,
376 (struct termio __user *)arg))
379 } else if (opt & TERMIOS_OLD) {
380 if (user_termios_to_kernel_termios_1(&tmp_termios,
381 (struct termios __user *)arg))
384 if (user_termios_to_kernel_termios(&tmp_termios,
385 (struct termios2 __user *)arg))
389 } else if (user_termios_to_kernel_termios(&tmp_termios,
390 (struct termios __user *)arg))
394 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
395 * with the real speed so its unconditionally usable */
396 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
397 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
399 ld = tty_ldisc_ref(tty);
402 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
403 ld->ops->flush_buffer(tty);
407 if (opt & TERMIOS_WAIT) {
408 tty_wait_until_sent(tty, 0);
409 if (signal_pending(current))
413 tty_set_termios(tty, &tmp_termios);
415 /* FIXME: Arguably if tmp_termios == tty->termios AND the
416 actual requested termios was not tmp_termios then we may
417 want to return an error as no user requested change has
422 static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
424 down_read(&tty->termios_rwsem);
425 *kterm = tty->termios;
426 up_read(&tty->termios_rwsem);
429 static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
431 down_read(&tty->termios_rwsem);
432 *kterm = tty->termios_locked;
433 up_read(&tty->termios_rwsem);
436 static int get_termio(struct tty_struct *tty, struct termio __user *termio)
438 struct ktermios kterm;
439 copy_termios(tty, &kterm);
440 if (kernel_termios_to_user_termio(termio, &kterm))
449 * set_termiox - set termiox fields if possible
451 * @arg: termiox structure from user
452 * @opt: option flags for ioctl type
454 * Implement the device calling points for the SYS5 termiox ioctl
458 static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
461 struct tty_ldisc *ld;
463 if (tty->termiox == NULL)
465 if (copy_from_user(&tnew, arg, sizeof(struct termiox)))
468 ld = tty_ldisc_ref(tty);
470 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
471 ld->ops->flush_buffer(tty);
474 if (opt & TERMIOS_WAIT) {
475 tty_wait_until_sent(tty, 0);
476 if (signal_pending(current))
480 down_write(&tty->termios_rwsem);
481 if (tty->ops->set_termiox)
482 tty->ops->set_termiox(tty, &tnew);
483 up_write(&tty->termios_rwsem);
492 * These are deprecated, but there is limited support..
494 * The "sg_flags" translation is a joke..
496 static int get_sgflags(struct tty_struct *tty)
500 if (!L_ICANON(tty)) {
502 flags |= 0x02; /* cbreak */
504 flags |= 0x20; /* raw */
507 flags |= 0x08; /* echo */
510 flags |= 0x10; /* crmod */
514 static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
518 down_read(&tty->termios_rwsem);
519 tmp.sg_ispeed = tty->termios.c_ispeed;
520 tmp.sg_ospeed = tty->termios.c_ospeed;
521 tmp.sg_erase = tty->termios.c_cc[VERASE];
522 tmp.sg_kill = tty->termios.c_cc[VKILL];
523 tmp.sg_flags = get_sgflags(tty);
524 up_read(&tty->termios_rwsem);
526 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
529 static void set_sgflags(struct ktermios *termios, int flags)
531 termios->c_iflag = ICRNL | IXON;
532 termios->c_oflag = 0;
533 termios->c_lflag = ISIG | ICANON;
534 if (flags & 0x02) { /* cbreak */
535 termios->c_iflag = 0;
536 termios->c_lflag &= ~ICANON;
538 if (flags & 0x08) { /* echo */
539 termios->c_lflag |= ECHO | ECHOE | ECHOK |
540 ECHOCTL | ECHOKE | IEXTEN;
542 if (flags & 0x10) { /* crmod */
543 termios->c_oflag |= OPOST | ONLCR;
545 if (flags & 0x20) { /* raw */
546 termios->c_iflag = 0;
547 termios->c_lflag &= ~(ISIG | ICANON);
549 if (!(termios->c_lflag & ICANON)) {
550 termios->c_cc[VMIN] = 1;
551 termios->c_cc[VTIME] = 0;
556 * set_sgttyb - set legacy terminal values
557 * @tty: tty structure
558 * @sgttyb: pointer to old style terminal structure
560 * Updates a terminal from the legacy BSD style terminal information
563 * Locking: termios_rwsem
566 static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
570 struct ktermios termios;
572 retval = tty_check_change(tty);
576 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
579 down_write(&tty->termios_rwsem);
580 termios = tty->termios;
581 termios.c_cc[VERASE] = tmp.sg_erase;
582 termios.c_cc[VKILL] = tmp.sg_kill;
583 set_sgflags(&termios, tmp.sg_flags);
584 /* Try and encode into Bfoo format */
586 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
589 up_write(&tty->termios_rwsem);
590 tty_set_termios(tty, &termios);
596 static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
600 down_read(&tty->termios_rwsem);
601 tmp.t_intrc = tty->termios.c_cc[VINTR];
602 tmp.t_quitc = tty->termios.c_cc[VQUIT];
603 tmp.t_startc = tty->termios.c_cc[VSTART];
604 tmp.t_stopc = tty->termios.c_cc[VSTOP];
605 tmp.t_eofc = tty->termios.c_cc[VEOF];
606 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
607 up_read(&tty->termios_rwsem);
608 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
611 static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
615 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
617 down_write(&tty->termios_rwsem);
618 tty->termios.c_cc[VINTR] = tmp.t_intrc;
619 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
620 tty->termios.c_cc[VSTART] = tmp.t_startc;
621 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
622 tty->termios.c_cc[VEOF] = tmp.t_eofc;
623 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
624 up_write(&tty->termios_rwsem);
630 static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
634 down_read(&tty->termios_rwsem);
635 tmp.t_suspc = tty->termios.c_cc[VSUSP];
636 /* what is dsuspc anyway? */
637 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
638 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
639 /* what is flushc anyway? */
640 tmp.t_flushc = tty->termios.c_cc[VEOL2];
641 tmp.t_werasc = tty->termios.c_cc[VWERASE];
642 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
643 up_read(&tty->termios_rwsem);
644 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
647 static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
651 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
654 down_write(&tty->termios_rwsem);
655 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
656 /* what is dsuspc anyway? */
657 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
658 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
659 /* what is flushc anyway? */
660 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
661 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
662 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
663 up_write(&tty->termios_rwsem);
669 * tty_change_softcar - carrier change ioctl helper
670 * @tty: tty to update
671 * @arg: enable/disable CLOCAL
673 * Perform a change to the CLOCAL state and call into the driver
674 * layer to make it visible. All done with the termios rwsem
677 static int tty_change_softcar(struct tty_struct *tty, int arg)
680 int bit = arg ? CLOCAL : 0;
683 down_write(&tty->termios_rwsem);
685 tty->termios.c_cflag &= ~CLOCAL;
686 tty->termios.c_cflag |= bit;
687 if (tty->ops->set_termios)
688 tty->ops->set_termios(tty, &old);
689 if (C_CLOCAL(tty) != bit)
691 up_write(&tty->termios_rwsem);
696 * tty_mode_ioctl - mode related ioctls
697 * @tty: tty for the ioctl
698 * @file: file pointer for the tty
700 * @arg: ioctl argument
702 * Perform non line discipline specific mode control ioctls. This
703 * is designed to be called by line disciplines to ensure they provide
704 * consistent mode setting.
707 int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
708 unsigned int cmd, unsigned long arg)
710 struct tty_struct *real_tty;
711 void __user *p = (void __user *)arg;
713 struct ktermios kterm;
715 BUG_ON(file == NULL);
717 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
718 tty->driver->subtype == PTY_TYPE_MASTER)
719 real_tty = tty->link;
726 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
729 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
733 return get_tchars(real_tty, p);
735 return set_tchars(real_tty, p);
739 return get_ltchars(real_tty, p);
741 return set_ltchars(real_tty, p);
744 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
746 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
748 return set_termios(real_tty, p, TERMIOS_OLD);
751 copy_termios(real_tty, &kterm);
752 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
757 copy_termios(real_tty, &kterm);
758 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
762 copy_termios(real_tty, &kterm);
763 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
767 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
769 return set_termios(real_tty, p, TERMIOS_WAIT);
771 return set_termios(real_tty, p, 0);
774 return get_termio(real_tty, p);
776 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
778 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
780 return set_termios(real_tty, p, TERMIOS_TERMIO);
783 copy_termios_locked(real_tty, &kterm);
784 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
788 if (!capable(CAP_SYS_ADMIN))
790 copy_termios_locked(real_tty, &kterm);
791 if (user_termios_to_kernel_termios(&kterm,
792 (struct termios __user *) arg))
794 down_write(&real_tty->termios_rwsem);
795 real_tty->termios_locked = kterm;
796 up_write(&real_tty->termios_rwsem);
800 copy_termios_locked(real_tty, &kterm);
801 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
805 if (!capable(CAP_SYS_ADMIN))
807 copy_termios_locked(real_tty, &kterm);
808 if (user_termios_to_kernel_termios_1(&kterm,
809 (struct termios __user *) arg))
811 down_write(&real_tty->termios_rwsem);
812 real_tty->termios_locked = kterm;
813 up_write(&real_tty->termios_rwsem);
818 struct termiox ktermx;
819 if (real_tty->termiox == NULL)
821 down_read(&real_tty->termios_rwsem);
822 memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
823 up_read(&real_tty->termios_rwsem);
824 if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
829 return set_termiox(real_tty, p, 0);
831 return set_termiox(real_tty, p, TERMIOS_WAIT);
833 return set_termiox(real_tty, p, TERMIOS_FLUSH);
836 copy_termios(real_tty, &kterm);
837 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
841 if (get_user(arg, (unsigned int __user *) arg))
843 return tty_change_softcar(real_tty, arg);
848 EXPORT_SYMBOL_GPL(tty_mode_ioctl);
851 /* Caller guarantees ldisc reference is held */
852 static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
854 struct tty_ldisc *ld = tty->ldisc;
858 if (ld && ld->ops->flush_buffer) {
859 ld->ops->flush_buffer(tty);
864 if (ld && ld->ops->flush_buffer) {
865 ld->ops->flush_buffer(tty);
870 tty_driver_flush_buffer(tty);
878 int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
880 struct tty_ldisc *ld;
881 int retval = tty_check_change(tty);
885 ld = tty_ldisc_ref_wait(tty);
886 retval = __tty_perform_flush(tty, arg);
891 EXPORT_SYMBOL_GPL(tty_perform_flush);
893 int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
894 unsigned int cmd, unsigned long arg)
900 retval = tty_check_change(tty);
905 spin_lock_irq(&tty->flow_lock);
906 if (!tty->flow_stopped) {
907 tty->flow_stopped = 1;
910 spin_unlock_irq(&tty->flow_lock);
913 spin_lock_irq(&tty->flow_lock);
914 if (tty->flow_stopped) {
915 tty->flow_stopped = 0;
918 spin_unlock_irq(&tty->flow_lock);
921 if (STOP_CHAR(tty) != __DISABLED_CHAR)
922 retval = tty_send_xchar(tty, STOP_CHAR(tty));
925 if (START_CHAR(tty) != __DISABLED_CHAR)
926 retval = tty_send_xchar(tty, START_CHAR(tty));
933 retval = tty_check_change(tty);
936 return __tty_perform_flush(tty, arg);
938 /* Try the mode commands */
939 return tty_mode_ioctl(tty, file, cmd, arg);
942 EXPORT_SYMBOL(n_tty_ioctl_helper);
945 long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
946 unsigned int cmd, unsigned long arg)
951 return tty_mode_ioctl(tty, file, cmd, (unsigned long) compat_ptr(arg));
956 EXPORT_SYMBOL(n_tty_compat_ioctl_helper);