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1/*
2 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
3 *
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).
7 */
8
9#include <linux/types.h>
10#include <linux/termios.h>
11#include <linux/errno.h>
12#include <linux/sched.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>
18#include <linux/mm.h>
19#include <linux/module.h>
20#include <linux/bitops.h>
21#include <linux/mutex.h>
22
23#include <asm/io.h>
24#include <asm/uaccess.h>
25#include <asm/system.h>
26
27#undef TTY_DEBUG_WAIT_UNTIL_SENT
28
29#undef DEBUG
30
31/*
32 * Internal flag options for termios setting behavior
33 */
34#define TERMIOS_FLUSH 1
35#define TERMIOS_WAIT 2
36#define TERMIOS_TERMIO 4
37#define TERMIOS_OLD 8
38
39
40/**
41 * tty_chars_in_buffer - characters pending
42 * @tty: terminal
43 *
44 * Return the number of bytes of data in the device private
45 * output queue. If no private method is supplied there is assumed
46 * to be no queue on the device.
47 */
48
49int tty_chars_in_buffer(struct tty_struct *tty)
50{
51 if (tty->ops->chars_in_buffer)
52 return tty->ops->chars_in_buffer(tty);
53 else
54 return 0;
55}
56EXPORT_SYMBOL(tty_chars_in_buffer);
57
58/**
59 * tty_write_room - write queue space
60 * @tty: terminal
61 *
62 * Return the number of bytes that can be queued to this device
63 * at the present time. The result should be treated as a guarantee
64 * and the driver cannot offer a value it later shrinks by more than
65 * the number of bytes written. If no method is provided 2K is always
66 * returned and data may be lost as there will be no flow control.
67 */
68
69int tty_write_room(struct tty_struct *tty)
70{
71 if (tty->ops->write_room)
72 return tty->ops->write_room(tty);
73 return 2048;
74}
75EXPORT_SYMBOL(tty_write_room);
76
77/**
78 * tty_driver_flush_buffer - discard internal buffer
79 * @tty: terminal
80 *
81 * Discard the internal output buffer for this device. If no method
82 * is provided then either the buffer cannot be hardware flushed or
83 * there is no buffer driver side.
84 */
85void tty_driver_flush_buffer(struct tty_struct *tty)
86{
87 if (tty->ops->flush_buffer)
88 tty->ops->flush_buffer(tty);
89}
90EXPORT_SYMBOL(tty_driver_flush_buffer);
91
92/**
93 * tty_throttle - flow control
94 * @tty: terminal
95 *
96 * Indicate that a tty should stop transmitting data down the stack.
97 * Takes the termios mutex to protect against parallel throttle/unthrottle
98 * and also to ensure the driver can consistently reference its own
99 * termios data at this point when implementing software flow control.
100 */
101
102void tty_throttle(struct tty_struct *tty)
103{
104 mutex_lock(&tty->termios_mutex);
105 /* check TTY_THROTTLED first so it indicates our state */
106 if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
107 tty->ops->throttle)
108 tty->ops->throttle(tty);
109 mutex_unlock(&tty->termios_mutex);
110}
111EXPORT_SYMBOL(tty_throttle);
112
113/**
114 * tty_unthrottle - flow control
115 * @tty: terminal
116 *
117 * Indicate that a tty may continue transmitting data down the stack.
118 * Takes the termios mutex to protect against parallel throttle/unthrottle
119 * and also to ensure the driver can consistently reference its own
120 * termios data at this point when implementing software flow control.
121 *
122 * Drivers should however remember that the stack can issue a throttle,
123 * then change flow control method, then unthrottle.
124 */
125
126void tty_unthrottle(struct tty_struct *tty)
127{
128 mutex_lock(&tty->termios_mutex);
129 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
130 tty->ops->unthrottle)
131 tty->ops->unthrottle(tty);
132 mutex_unlock(&tty->termios_mutex);
133}
134EXPORT_SYMBOL(tty_unthrottle);
135
136/**
137 * tty_wait_until_sent - wait for I/O to finish
138 * @tty: tty we are waiting for
139 * @timeout: how long we will wait
140 *
141 * Wait for characters pending in a tty driver to hit the wire, or
142 * for a timeout to occur (eg due to flow control)
143 *
144 * Locking: none
145 */
146
147void tty_wait_until_sent(struct tty_struct *tty, long timeout)
148{
149#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
150 char buf[64];
151
152 printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf));
153#endif
154 if (!timeout)
155 timeout = MAX_SCHEDULE_TIMEOUT;
156 if (wait_event_interruptible_timeout(tty->write_wait,
157 !tty_chars_in_buffer(tty), timeout) >= 0) {
158 if (tty->ops->wait_until_sent)
159 tty->ops->wait_until_sent(tty, timeout);
160 }
161}
162EXPORT_SYMBOL(tty_wait_until_sent);
163
164
165/*
166 * Termios Helper Methods
167 */
168
169static void unset_locked_termios(struct ktermios *termios,
170 struct ktermios *old,
171 struct ktermios *locked)
172{
173 int i;
174
175#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
176
177 if (!locked) {
178 printk(KERN_WARNING "Warning?!? termios_locked is NULL.\n");
179 return;
180 }
181
182 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
183 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
184 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
185 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
186 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
187 for (i = 0; i < NCCS; i++)
188 termios->c_cc[i] = locked->c_cc[i] ?
189 old->c_cc[i] : termios->c_cc[i];
190 /* FIXME: What should we do for i/ospeed */
191}
192
193/*
194 * Routine which returns the baud rate of the tty
195 *
196 * Note that the baud_table needs to be kept in sync with the
197 * include/asm/termbits.h file.
198 */
199static const speed_t baud_table[] = {
200 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
201 9600, 19200, 38400, 57600, 115200, 230400, 460800,
202#ifdef __sparc__
203 76800, 153600, 307200, 614400, 921600
204#else
205 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
206 2500000, 3000000, 3500000, 4000000
207#endif
208};
209
210#ifndef __sparc__
211static const tcflag_t baud_bits[] = {
212 B0, B50, B75, B110, B134, B150, B200, B300, B600,
213 B1200, B1800, B2400, B4800, B9600, B19200, B38400,
214 B57600, B115200, B230400, B460800, B500000, B576000,
215 B921600, B1000000, B1152000, B1500000, B2000000, B2500000,
216 B3000000, B3500000, B4000000
217};
218#else
219static const tcflag_t baud_bits[] = {
220 B0, B50, B75, B110, B134, B150, B200, B300, B600,
221 B1200, B1800, B2400, B4800, B9600, B19200, B38400,
222 B57600, B115200, B230400, B460800, B76800, B153600,
223 B307200, B614400, B921600
224};
225#endif
226
227static int n_baud_table = ARRAY_SIZE(baud_table);
228
229/**
230 * tty_termios_baud_rate
231 * @termios: termios structure
232 *
233 * Convert termios baud rate data into a speed. This should be called
234 * with the termios lock held if this termios is a terminal termios
235 * structure. May change the termios data. Device drivers can call this
236 * function but should use ->c_[io]speed directly as they are updated.
237 *
238 * Locking: none
239 */
240
241speed_t tty_termios_baud_rate(struct ktermios *termios)
242{
243 unsigned int cbaud;
244
245 cbaud = termios->c_cflag & CBAUD;
246
247#ifdef BOTHER
248 /* Magic token for arbitrary speed via c_ispeed/c_ospeed */
249 if (cbaud == BOTHER)
250 return termios->c_ospeed;
251#endif
252 if (cbaud & CBAUDEX) {
253 cbaud &= ~CBAUDEX;
254
255 if (cbaud < 1 || cbaud + 15 > n_baud_table)
256 termios->c_cflag &= ~CBAUDEX;
257 else
258 cbaud += 15;
259 }
260 return baud_table[cbaud];
261}
262EXPORT_SYMBOL(tty_termios_baud_rate);
263
264/**
265 * tty_termios_input_baud_rate
266 * @termios: termios structure
267 *
268 * Convert termios baud rate data into a speed. This should be called
269 * with the termios lock held if this termios is a terminal termios
270 * structure. May change the termios data. Device drivers can call this
271 * function but should use ->c_[io]speed directly as they are updated.
272 *
273 * Locking: none
274 */
275
276speed_t tty_termios_input_baud_rate(struct ktermios *termios)
277{
278#ifdef IBSHIFT
279 unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD;
280
281 if (cbaud == B0)
282 return tty_termios_baud_rate(termios);
283
284 /* Magic token for arbitrary speed via c_ispeed*/
285 if (cbaud == BOTHER)
286 return termios->c_ispeed;
287
288 if (cbaud & CBAUDEX) {
289 cbaud &= ~CBAUDEX;
290
291 if (cbaud < 1 || cbaud + 15 > n_baud_table)
292 termios->c_cflag &= ~(CBAUDEX << IBSHIFT);
293 else
294 cbaud += 15;
295 }
296 return baud_table[cbaud];
297#else
298 return tty_termios_baud_rate(termios);
299#endif
300}
301EXPORT_SYMBOL(tty_termios_input_baud_rate);
302
303/**
304 * tty_termios_encode_baud_rate
305 * @termios: ktermios structure holding user requested state
306 * @ispeed: input speed
307 * @ospeed: output speed
308 *
309 * Encode the speeds set into the passed termios structure. This is
310 * used as a library helper for drivers so that they can report back
311 * the actual speed selected when it differs from the speed requested
312 *
313 * For maximal back compatibility with legacy SYS5/POSIX *nix behaviour
314 * we need to carefully set the bits when the user does not get the
315 * desired speed. We allow small margins and preserve as much of possible
316 * of the input intent to keep compatibility.
317 *
318 * Locking: Caller should hold termios lock. This is already held
319 * when calling this function from the driver termios handler.
320 *
321 * The ifdefs deal with platforms whose owners have yet to update them
322 * and will all go away once this is done.
323 */
324
325void tty_termios_encode_baud_rate(struct ktermios *termios,
326 speed_t ibaud, speed_t obaud)
327{
328 int i = 0;
329 int ifound = -1, ofound = -1;
330 int iclose = ibaud/50, oclose = obaud/50;
331 int ibinput = 0;
332
333 if (obaud == 0) /* CD dropped */
334 ibaud = 0; /* Clear ibaud to be sure */
335
336 termios->c_ispeed = ibaud;
337 termios->c_ospeed = obaud;
338
339#ifdef BOTHER
340 /* If the user asked for a precise weird speed give a precise weird
341 answer. If they asked for a Bfoo speed they many have problems
342 digesting non-exact replies so fuzz a bit */
343
344 if ((termios->c_cflag & CBAUD) == BOTHER)
345 oclose = 0;
346 if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER)
347 iclose = 0;
348 if ((termios->c_cflag >> IBSHIFT) & CBAUD)
349 ibinput = 1; /* An input speed was specified */
350#endif
351 termios->c_cflag &= ~CBAUD;
352
353 /*
354 * Our goal is to find a close match to the standard baud rate
355 * returned. Walk the baud rate table and if we get a very close
356 * match then report back the speed as a POSIX Bxxxx value by
357 * preference
358 */
359
360 do {
361 if (obaud - oclose <= baud_table[i] &&
362 obaud + oclose >= baud_table[i]) {
363 termios->c_cflag |= baud_bits[i];
364 ofound = i;
365 }
366 if (ibaud - iclose <= baud_table[i] &&
367 ibaud + iclose >= baud_table[i]) {
368 /* For the case input == output don't set IBAUD bits
369 if the user didn't do so */
370 if (ofound == i && !ibinput)
371 ifound = i;
372#ifdef IBSHIFT
373 else {
374 ifound = i;
375 termios->c_cflag |= (baud_bits[i] << IBSHIFT);
376 }
377#endif
378 }
379 } while (++i < n_baud_table);
380
381 /*
382 * If we found no match then use BOTHER if provided or warn
383 * the user their platform maintainer needs to wake up if not.
384 */
385#ifdef BOTHER
386 if (ofound == -1)
387 termios->c_cflag |= BOTHER;
388 /* Set exact input bits only if the input and output differ or the
389 user already did */
390 if (ifound == -1 && (ibaud != obaud || ibinput))
391 termios->c_cflag |= (BOTHER << IBSHIFT);
392#else
393 if (ifound == -1 || ofound == -1) {
394 printk_once(KERN_WARNING "tty: Unable to return correct "
395 "speed data as your architecture needs updating.\n");
396 }
397#endif
398}
399EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
400
401/**
402 * tty_encode_baud_rate - set baud rate of the tty
403 * @ibaud: input baud rate
404 * @obad: output baud rate
405 *
406 * Update the current termios data for the tty with the new speed
407 * settings. The caller must hold the termios_mutex for the tty in
408 * question.
409 */
410
411void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
412{
413 tty_termios_encode_baud_rate(tty->termios, ibaud, obaud);
414}
415EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
416
417/**
418 * tty_get_baud_rate - get tty bit rates
419 * @tty: tty to query
420 *
421 * Returns the baud rate as an integer for this terminal. The
422 * termios lock must be held by the caller and the terminal bit
423 * flags may be updated.
424 *
425 * Locking: none
426 */
427
428speed_t tty_get_baud_rate(struct tty_struct *tty)
429{
430 speed_t baud = tty_termios_baud_rate(tty->termios);
431
432 if (baud == 38400 && tty->alt_speed) {
433 if (!tty->warned) {
434 printk(KERN_WARNING "Use of setserial/setrocket to "
435 "set SPD_* flags is deprecated\n");
436 tty->warned = 1;
437 }
438 baud = tty->alt_speed;
439 }
440
441 return baud;
442}
443EXPORT_SYMBOL(tty_get_baud_rate);
444
445/**
446 * tty_termios_copy_hw - copy hardware settings
447 * @new: New termios
448 * @old: Old termios
449 *
450 * Propagate the hardware specific terminal setting bits from
451 * the old termios structure to the new one. This is used in cases
452 * where the hardware does not support reconfiguration or as a helper
453 * in some cases where only minimal reconfiguration is supported
454 */
455
456void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
457{
458 /* The bits a dumb device handles in software. Smart devices need
459 to always provide a set_termios method */
460 new->c_cflag &= HUPCL | CREAD | CLOCAL;
461 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
462 new->c_ispeed = old->c_ispeed;
463 new->c_ospeed = old->c_ospeed;
464}
465EXPORT_SYMBOL(tty_termios_copy_hw);
466
467/**
468 * tty_termios_hw_change - check for setting change
469 * @a: termios
470 * @b: termios to compare
471 *
472 * Check if any of the bits that affect a dumb device have changed
473 * between the two termios structures, or a speed change is needed.
474 */
475
476int tty_termios_hw_change(struct ktermios *a, struct ktermios *b)
477{
478 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
479 return 1;
480 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
481 return 1;
482 return 0;
483}
484EXPORT_SYMBOL(tty_termios_hw_change);
485
486/**
487 * tty_set_termios - update termios values
488 * @tty: tty to update
489 * @new_termios: desired new value
490 *
491 * Perform updates to the termios values set on this terminal. There
492 * is a bit of layering violation here with n_tty in terms of the
493 * internal knowledge of this function.
494 *
495 * Locking: termios_mutex
496 */
497
498int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
499{
500 struct ktermios old_termios;
501 struct tty_ldisc *ld;
502 unsigned long flags;
503
504 /*
505 * Perform the actual termios internal changes under lock.
506 */
507
508
509 /* FIXME: we need to decide on some locking/ordering semantics
510 for the set_termios notification eventually */
511 mutex_lock(&tty->termios_mutex);
512 old_termios = *tty->termios;
513 *tty->termios = *new_termios;
514 unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
515
516 /* See if packet mode change of state. */
517 if (tty->link && tty->link->packet) {
518 int extproc = (old_termios.c_lflag & EXTPROC) |
519 (tty->termios->c_lflag & EXTPROC);
520 int old_flow = ((old_termios.c_iflag & IXON) &&
521 (old_termios.c_cc[VSTOP] == '\023') &&
522 (old_termios.c_cc[VSTART] == '\021'));
523 int new_flow = (I_IXON(tty) &&
524 STOP_CHAR(tty) == '\023' &&
525 START_CHAR(tty) == '\021');
526 if ((old_flow != new_flow) || extproc) {
527 spin_lock_irqsave(&tty->ctrl_lock, flags);
528 if (old_flow != new_flow) {
529 tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
530 if (new_flow)
531 tty->ctrl_status |= TIOCPKT_DOSTOP;
532 else
533 tty->ctrl_status |= TIOCPKT_NOSTOP;
534 }
535 if (extproc)
536 tty->ctrl_status |= TIOCPKT_IOCTL;
537 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
538 wake_up_interruptible(&tty->link->read_wait);
539 }
540 }
541
542 if (tty->ops->set_termios)
543 (*tty->ops->set_termios)(tty, &old_termios);
544 else
545 tty_termios_copy_hw(tty->termios, &old_termios);
546
547 ld = tty_ldisc_ref(tty);
548 if (ld != NULL) {
549 if (ld->ops->set_termios)
550 (ld->ops->set_termios)(tty, &old_termios);
551 tty_ldisc_deref(ld);
552 }
553 mutex_unlock(&tty->termios_mutex);
554 return 0;
555}
556EXPORT_SYMBOL_GPL(tty_set_termios);
557
558/**
559 * set_termios - set termios values for a tty
560 * @tty: terminal device
561 * @arg: user data
562 * @opt: option information
563 *
564 * Helper function to prepare termios data and run necessary other
565 * functions before using tty_set_termios to do the actual changes.
566 *
567 * Locking:
568 * Called functions take ldisc and termios_mutex locks
569 */
570
571static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
572{
573 struct ktermios tmp_termios;
574 struct tty_ldisc *ld;
575 int retval = tty_check_change(tty);
576
577 if (retval)
578 return retval;
579
580 mutex_lock(&tty->termios_mutex);
581 memcpy(&tmp_termios, tty->termios, sizeof(struct ktermios));
582 mutex_unlock(&tty->termios_mutex);
583
584 if (opt & TERMIOS_TERMIO) {
585 if (user_termio_to_kernel_termios(&tmp_termios,
586 (struct termio __user *)arg))
587 return -EFAULT;
588#ifdef TCGETS2
589 } else if (opt & TERMIOS_OLD) {
590 if (user_termios_to_kernel_termios_1(&tmp_termios,
591 (struct termios __user *)arg))
592 return -EFAULT;
593 } else {
594 if (user_termios_to_kernel_termios(&tmp_termios,
595 (struct termios2 __user *)arg))
596 return -EFAULT;
597 }
598#else
599 } else if (user_termios_to_kernel_termios(&tmp_termios,
600 (struct termios __user *)arg))
601 return -EFAULT;
602#endif
603
604 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
605 * with the real speed so its unconditionally usable */
606 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
607 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
608
609 ld = tty_ldisc_ref(tty);
610
611 if (ld != NULL) {
612 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
613 ld->ops->flush_buffer(tty);
614 tty_ldisc_deref(ld);
615 }
616
617 if (opt & TERMIOS_WAIT) {
618 tty_wait_until_sent(tty, 0);
619 if (signal_pending(current))
620 return -EINTR;
621 }
622
623 tty_set_termios(tty, &tmp_termios);
624
625 /* FIXME: Arguably if tmp_termios == tty->termios AND the
626 actual requested termios was not tmp_termios then we may
627 want to return an error as no user requested change has
628 succeeded */
629 return 0;
630}
631
632static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
633{
634 mutex_lock(&tty->termios_mutex);
635 memcpy(kterm, tty->termios, sizeof(struct ktermios));
636 mutex_unlock(&tty->termios_mutex);
637}
638
639static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
640{
641 mutex_lock(&tty->termios_mutex);
642 memcpy(kterm, tty->termios_locked, sizeof(struct ktermios));
643 mutex_unlock(&tty->termios_mutex);
644}
645
646static int get_termio(struct tty_struct *tty, struct termio __user *termio)
647{
648 struct ktermios kterm;
649 copy_termios(tty, &kterm);
650 if (kernel_termios_to_user_termio(termio, &kterm))
651 return -EFAULT;
652 return 0;
653}
654
655
656#ifdef TCGETX
657
658/**
659 * set_termiox - set termiox fields if possible
660 * @tty: terminal
661 * @arg: termiox structure from user
662 * @opt: option flags for ioctl type
663 *
664 * Implement the device calling points for the SYS5 termiox ioctl
665 * interface in Linux
666 */
667
668static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
669{
670 struct termiox tnew;
671 struct tty_ldisc *ld;
672
673 if (tty->termiox == NULL)
674 return -EINVAL;
675 if (copy_from_user(&tnew, arg, sizeof(struct termiox)))
676 return -EFAULT;
677
678 ld = tty_ldisc_ref(tty);
679 if (ld != NULL) {
680 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
681 ld->ops->flush_buffer(tty);
682 tty_ldisc_deref(ld);
683 }
684 if (opt & TERMIOS_WAIT) {
685 tty_wait_until_sent(tty, 0);
686 if (signal_pending(current))
687 return -EINTR;
688 }
689
690 mutex_lock(&tty->termios_mutex);
691 if (tty->ops->set_termiox)
692 tty->ops->set_termiox(tty, &tnew);
693 mutex_unlock(&tty->termios_mutex);
694 return 0;
695}
696
697#endif
698
699
700#ifdef TIOCGETP
701/*
702 * These are deprecated, but there is limited support..
703 *
704 * The "sg_flags" translation is a joke..
705 */
706static int get_sgflags(struct tty_struct *tty)
707{
708 int flags = 0;
709
710 if (!(tty->termios->c_lflag & ICANON)) {
711 if (tty->termios->c_lflag & ISIG)
712 flags |= 0x02; /* cbreak */
713 else
714 flags |= 0x20; /* raw */
715 }
716 if (tty->termios->c_lflag & ECHO)
717 flags |= 0x08; /* echo */
718 if (tty->termios->c_oflag & OPOST)
719 if (tty->termios->c_oflag & ONLCR)
720 flags |= 0x10; /* crmod */
721 return flags;
722}
723
724static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
725{
726 struct sgttyb tmp;
727
728 mutex_lock(&tty->termios_mutex);
729 tmp.sg_ispeed = tty->termios->c_ispeed;
730 tmp.sg_ospeed = tty->termios->c_ospeed;
731 tmp.sg_erase = tty->termios->c_cc[VERASE];
732 tmp.sg_kill = tty->termios->c_cc[VKILL];
733 tmp.sg_flags = get_sgflags(tty);
734 mutex_unlock(&tty->termios_mutex);
735
736 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
737}
738
739static void set_sgflags(struct ktermios *termios, int flags)
740{
741 termios->c_iflag = ICRNL | IXON;
742 termios->c_oflag = 0;
743 termios->c_lflag = ISIG | ICANON;
744 if (flags & 0x02) { /* cbreak */
745 termios->c_iflag = 0;
746 termios->c_lflag &= ~ICANON;
747 }
748 if (flags & 0x08) { /* echo */
749 termios->c_lflag |= ECHO | ECHOE | ECHOK |
750 ECHOCTL | ECHOKE | IEXTEN;
751 }
752 if (flags & 0x10) { /* crmod */
753 termios->c_oflag |= OPOST | ONLCR;
754 }
755 if (flags & 0x20) { /* raw */
756 termios->c_iflag = 0;
757 termios->c_lflag &= ~(ISIG | ICANON);
758 }
759 if (!(termios->c_lflag & ICANON)) {
760 termios->c_cc[VMIN] = 1;
761 termios->c_cc[VTIME] = 0;
762 }
763}
764
765/**
766 * set_sgttyb - set legacy terminal values
767 * @tty: tty structure
768 * @sgttyb: pointer to old style terminal structure
769 *
770 * Updates a terminal from the legacy BSD style terminal information
771 * structure.
772 *
773 * Locking: termios_mutex
774 */
775
776static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
777{
778 int retval;
779 struct sgttyb tmp;
780 struct ktermios termios;
781
782 retval = tty_check_change(tty);
783 if (retval)
784 return retval;
785
786 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
787 return -EFAULT;
788
789 mutex_lock(&tty->termios_mutex);
790 termios = *tty->termios;
791 termios.c_cc[VERASE] = tmp.sg_erase;
792 termios.c_cc[VKILL] = tmp.sg_kill;
793 set_sgflags(&termios, tmp.sg_flags);
794 /* Try and encode into Bfoo format */
795#ifdef BOTHER
796 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
797 termios.c_ospeed);
798#endif
799 mutex_unlock(&tty->termios_mutex);
800 tty_set_termios(tty, &termios);
801 return 0;
802}
803#endif
804
805#ifdef TIOCGETC
806static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
807{
808 struct tchars tmp;
809
810 mutex_lock(&tty->termios_mutex);
811 tmp.t_intrc = tty->termios->c_cc[VINTR];
812 tmp.t_quitc = tty->termios->c_cc[VQUIT];
813 tmp.t_startc = tty->termios->c_cc[VSTART];
814 tmp.t_stopc = tty->termios->c_cc[VSTOP];
815 tmp.t_eofc = tty->termios->c_cc[VEOF];
816 tmp.t_brkc = tty->termios->c_cc[VEOL2]; /* what is brkc anyway? */
817 mutex_unlock(&tty->termios_mutex);
818 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
819}
820
821static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
822{
823 struct tchars tmp;
824
825 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
826 return -EFAULT;
827 mutex_lock(&tty->termios_mutex);
828 tty->termios->c_cc[VINTR] = tmp.t_intrc;
829 tty->termios->c_cc[VQUIT] = tmp.t_quitc;
830 tty->termios->c_cc[VSTART] = tmp.t_startc;
831 tty->termios->c_cc[VSTOP] = tmp.t_stopc;
832 tty->termios->c_cc[VEOF] = tmp.t_eofc;
833 tty->termios->c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
834 mutex_unlock(&tty->termios_mutex);
835 return 0;
836}
837#endif
838
839#ifdef TIOCGLTC
840static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
841{
842 struct ltchars tmp;
843
844 mutex_lock(&tty->termios_mutex);
845 tmp.t_suspc = tty->termios->c_cc[VSUSP];
846 /* what is dsuspc anyway? */
847 tmp.t_dsuspc = tty->termios->c_cc[VSUSP];
848 tmp.t_rprntc = tty->termios->c_cc[VREPRINT];
849 /* what is flushc anyway? */
850 tmp.t_flushc = tty->termios->c_cc[VEOL2];
851 tmp.t_werasc = tty->termios->c_cc[VWERASE];
852 tmp.t_lnextc = tty->termios->c_cc[VLNEXT];
853 mutex_unlock(&tty->termios_mutex);
854 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
855}
856
857static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
858{
859 struct ltchars tmp;
860
861 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
862 return -EFAULT;
863
864 mutex_lock(&tty->termios_mutex);
865 tty->termios->c_cc[VSUSP] = tmp.t_suspc;
866 /* what is dsuspc anyway? */
867 tty->termios->c_cc[VEOL2] = tmp.t_dsuspc;
868 tty->termios->c_cc[VREPRINT] = tmp.t_rprntc;
869 /* what is flushc anyway? */
870 tty->termios->c_cc[VEOL2] = tmp.t_flushc;
871 tty->termios->c_cc[VWERASE] = tmp.t_werasc;
872 tty->termios->c_cc[VLNEXT] = tmp.t_lnextc;
873 mutex_unlock(&tty->termios_mutex);
874 return 0;
875}
876#endif
877
878/**
879 * send_prio_char - send priority character
880 *
881 * Send a high priority character to the tty even if stopped
882 *
883 * Locking: none for xchar method, write ordering for write method.
884 */
885
886static int send_prio_char(struct tty_struct *tty, char ch)
887{
888 int was_stopped = tty->stopped;
889
890 if (tty->ops->send_xchar) {
891 tty->ops->send_xchar(tty, ch);
892 return 0;
893 }
894
895 if (tty_write_lock(tty, 0) < 0)
896 return -ERESTARTSYS;
897
898 if (was_stopped)
899 start_tty(tty);
900 tty->ops->write(tty, &ch, 1);
901 if (was_stopped)
902 stop_tty(tty);
903 tty_write_unlock(tty);
904 return 0;
905}
906
907/**
908 * tty_change_softcar - carrier change ioctl helper
909 * @tty: tty to update
910 * @arg: enable/disable CLOCAL
911 *
912 * Perform a change to the CLOCAL state and call into the driver
913 * layer to make it visible. All done with the termios mutex
914 */
915
916static int tty_change_softcar(struct tty_struct *tty, int arg)
917{
918 int ret = 0;
919 int bit = arg ? CLOCAL : 0;
920 struct ktermios old;
921
922 mutex_lock(&tty->termios_mutex);
923 old = *tty->termios;
924 tty->termios->c_cflag &= ~CLOCAL;
925 tty->termios->c_cflag |= bit;
926 if (tty->ops->set_termios)
927 tty->ops->set_termios(tty, &old);
928 if ((tty->termios->c_cflag & CLOCAL) != bit)
929 ret = -EINVAL;
930 mutex_unlock(&tty->termios_mutex);
931 return ret;
932}
933
934/**
935 * tty_mode_ioctl - mode related ioctls
936 * @tty: tty for the ioctl
937 * @file: file pointer for the tty
938 * @cmd: command
939 * @arg: ioctl argument
940 *
941 * Perform non line discipline specific mode control ioctls. This
942 * is designed to be called by line disciplines to ensure they provide
943 * consistent mode setting.
944 */
945
946int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
947 unsigned int cmd, unsigned long arg)
948{
949 struct tty_struct *real_tty;
950 void __user *p = (void __user *)arg;
951 int ret = 0;
952 struct ktermios kterm;
953
954 BUG_ON(file == NULL);
955
956 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
957 tty->driver->subtype == PTY_TYPE_MASTER)
958 real_tty = tty->link;
959 else
960 real_tty = tty;
961
962 switch (cmd) {
963#ifdef TIOCGETP
964 case TIOCGETP:
965 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
966 case TIOCSETP:
967 case TIOCSETN:
968 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
969#endif
970#ifdef TIOCGETC
971 case TIOCGETC:
972 return get_tchars(real_tty, p);
973 case TIOCSETC:
974 return set_tchars(real_tty, p);
975#endif
976#ifdef TIOCGLTC
977 case TIOCGLTC:
978 return get_ltchars(real_tty, p);
979 case TIOCSLTC:
980 return set_ltchars(real_tty, p);
981#endif
982 case TCSETSF:
983 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
984 case TCSETSW:
985 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
986 case TCSETS:
987 return set_termios(real_tty, p, TERMIOS_OLD);
988#ifndef TCGETS2
989 case TCGETS:
990 copy_termios(real_tty, &kterm);
991 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
992 ret = -EFAULT;
993 return ret;
994#else
995 case TCGETS:
996 copy_termios(real_tty, &kterm);
997 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
998 ret = -EFAULT;
999 return ret;
1000 case TCGETS2:
1001 copy_termios(real_tty, &kterm);
1002 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
1003 ret = -EFAULT;
1004 return ret;
1005 case TCSETSF2:
1006 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
1007 case TCSETSW2:
1008 return set_termios(real_tty, p, TERMIOS_WAIT);
1009 case TCSETS2:
1010 return set_termios(real_tty, p, 0);
1011#endif
1012 case TCGETA:
1013 return get_termio(real_tty, p);
1014 case TCSETAF:
1015 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
1016 case TCSETAW:
1017 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
1018 case TCSETA:
1019 return set_termios(real_tty, p, TERMIOS_TERMIO);
1020#ifndef TCGETS2
1021 case TIOCGLCKTRMIOS:
1022 copy_termios_locked(real_tty, &kterm);
1023 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
1024 ret = -EFAULT;
1025 return ret;
1026 case TIOCSLCKTRMIOS:
1027 if (!capable(CAP_SYS_ADMIN))
1028 return -EPERM;
1029 copy_termios_locked(real_tty, &kterm);
1030 if (user_termios_to_kernel_termios(&kterm,
1031 (struct termios __user *) arg))
1032 return -EFAULT;
1033 mutex_lock(&real_tty->termios_mutex);
1034 memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
1035 mutex_unlock(&real_tty->termios_mutex);
1036 return 0;
1037#else
1038 case TIOCGLCKTRMIOS:
1039 copy_termios_locked(real_tty, &kterm);
1040 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
1041 ret = -EFAULT;
1042 return ret;
1043 case TIOCSLCKTRMIOS:
1044 if (!capable(CAP_SYS_ADMIN))
1045 return -EPERM;
1046 copy_termios_locked(real_tty, &kterm);
1047 if (user_termios_to_kernel_termios_1(&kterm,
1048 (struct termios __user *) arg))
1049 return -EFAULT;
1050 mutex_lock(&real_tty->termios_mutex);
1051 memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
1052 mutex_unlock(&real_tty->termios_mutex);
1053 return ret;
1054#endif
1055#ifdef TCGETX
1056 case TCGETX: {
1057 struct termiox ktermx;
1058 if (real_tty->termiox == NULL)
1059 return -EINVAL;
1060 mutex_lock(&real_tty->termios_mutex);
1061 memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
1062 mutex_unlock(&real_tty->termios_mutex);
1063 if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
1064 ret = -EFAULT;
1065 return ret;
1066 }
1067 case TCSETX:
1068 return set_termiox(real_tty, p, 0);
1069 case TCSETXW:
1070 return set_termiox(real_tty, p, TERMIOS_WAIT);
1071 case TCSETXF:
1072 return set_termiox(real_tty, p, TERMIOS_FLUSH);
1073#endif
1074 case TIOCGSOFTCAR:
1075 copy_termios(real_tty, &kterm);
1076 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
1077 (int __user *)arg);
1078 return ret;
1079 case TIOCSSOFTCAR:
1080 if (get_user(arg, (unsigned int __user *) arg))
1081 return -EFAULT;
1082 return tty_change_softcar(real_tty, arg);
1083 default:
1084 return -ENOIOCTLCMD;
1085 }
1086}
1087EXPORT_SYMBOL_GPL(tty_mode_ioctl);
1088
1089int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
1090{
1091 struct tty_ldisc *ld;
1092 int retval = tty_check_change(tty);
1093 if (retval)
1094 return retval;
1095
1096 ld = tty_ldisc_ref_wait(tty);
1097 switch (arg) {
1098 case TCIFLUSH:
1099 if (ld && ld->ops->flush_buffer)
1100 ld->ops->flush_buffer(tty);
1101 break;
1102 case TCIOFLUSH:
1103 if (ld && ld->ops->flush_buffer)
1104 ld->ops->flush_buffer(tty);
1105 /* fall through */
1106 case TCOFLUSH:
1107 tty_driver_flush_buffer(tty);
1108 break;
1109 default:
1110 tty_ldisc_deref(ld);
1111 return -EINVAL;
1112 }
1113 tty_ldisc_deref(ld);
1114 return 0;
1115}
1116EXPORT_SYMBOL_GPL(tty_perform_flush);
1117
1118int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
1119 unsigned int cmd, unsigned long arg)
1120{
1121 unsigned long flags;
1122 int retval;
1123
1124 switch (cmd) {
1125 case TCXONC:
1126 retval = tty_check_change(tty);
1127 if (retval)
1128 return retval;
1129 switch (arg) {
1130 case TCOOFF:
1131 if (!tty->flow_stopped) {
1132 tty->flow_stopped = 1;
1133 stop_tty(tty);
1134 }
1135 break;
1136 case TCOON:
1137 if (tty->flow_stopped) {
1138 tty->flow_stopped = 0;
1139 start_tty(tty);
1140 }
1141 break;
1142 case TCIOFF:
1143 if (STOP_CHAR(tty) != __DISABLED_CHAR)
1144 return send_prio_char(tty, STOP_CHAR(tty));
1145 break;
1146 case TCION:
1147 if (START_CHAR(tty) != __DISABLED_CHAR)
1148 return send_prio_char(tty, START_CHAR(tty));
1149 break;
1150 default:
1151 return -EINVAL;
1152 }
1153 return 0;
1154 case TCFLSH:
1155 return tty_perform_flush(tty, arg);
1156 case TIOCPKT:
1157 {
1158 int pktmode;
1159
1160 if (tty->driver->type != TTY_DRIVER_TYPE_PTY ||
1161 tty->driver->subtype != PTY_TYPE_MASTER)
1162 return -ENOTTY;
1163 if (get_user(pktmode, (int __user *) arg))
1164 return -EFAULT;
1165 spin_lock_irqsave(&tty->ctrl_lock, flags);
1166 if (pktmode) {
1167 if (!tty->packet) {
1168 tty->packet = 1;
1169 tty->link->ctrl_status = 0;
1170 }
1171 } else
1172 tty->packet = 0;
1173 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1174 return 0;
1175 }
1176 default:
1177 /* Try the mode commands */
1178 return tty_mode_ioctl(tty, file, cmd, arg);
1179 }
1180}
1181EXPORT_SYMBOL(n_tty_ioctl_helper);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
4 *
5 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
6 * which can be dynamically activated and de-activated by the line
7 * discipline handling modules (like SLIP).
8 */
9
10#include <linux/types.h>
11#include <linux/termios.h>
12#include <linux/errno.h>
13#include <linux/sched/signal.h>
14#include <linux/kernel.h>
15#include <linux/major.h>
16#include <linux/tty.h>
17#include <linux/fcntl.h>
18#include <linux/string.h>
19#include <linux/mm.h>
20#include <linux/module.h>
21#include <linux/bitops.h>
22#include <linux/mutex.h>
23#include <linux/compat.h>
24#include "tty.h"
25
26#include <asm/io.h>
27#include <linux/uaccess.h>
28
29#undef TTY_DEBUG_WAIT_UNTIL_SENT
30
31#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
32# define tty_debug_wait_until_sent(tty, f, args...) tty_debug(tty, f, ##args)
33#else
34# define tty_debug_wait_until_sent(tty, f, args...) do {} while (0)
35#endif
36
37#undef DEBUG
38
39/*
40 * Internal flag options for termios setting behavior
41 */
42#define TERMIOS_FLUSH 1
43#define TERMIOS_WAIT 2
44#define TERMIOS_TERMIO 4
45#define TERMIOS_OLD 8
46
47
48/**
49 * tty_chars_in_buffer - characters pending
50 * @tty: terminal
51 *
52 * Return the number of bytes of data in the device private
53 * output queue. If no private method is supplied there is assumed
54 * to be no queue on the device.
55 */
56
57unsigned int tty_chars_in_buffer(struct tty_struct *tty)
58{
59 if (tty->ops->chars_in_buffer)
60 return tty->ops->chars_in_buffer(tty);
61 return 0;
62}
63EXPORT_SYMBOL(tty_chars_in_buffer);
64
65/**
66 * tty_write_room - write queue space
67 * @tty: terminal
68 *
69 * Return the number of bytes that can be queued to this device
70 * at the present time. The result should be treated as a guarantee
71 * and the driver cannot offer a value it later shrinks by more than
72 * the number of bytes written. If no method is provided 2K is always
73 * returned and data may be lost as there will be no flow control.
74 */
75
76unsigned int tty_write_room(struct tty_struct *tty)
77{
78 if (tty->ops->write_room)
79 return tty->ops->write_room(tty);
80 return 2048;
81}
82EXPORT_SYMBOL(tty_write_room);
83
84/**
85 * tty_driver_flush_buffer - discard internal buffer
86 * @tty: terminal
87 *
88 * Discard the internal output buffer for this device. If no method
89 * is provided then either the buffer cannot be hardware flushed or
90 * there is no buffer driver side.
91 */
92void tty_driver_flush_buffer(struct tty_struct *tty)
93{
94 if (tty->ops->flush_buffer)
95 tty->ops->flush_buffer(tty);
96}
97EXPORT_SYMBOL(tty_driver_flush_buffer);
98
99/**
100 * tty_unthrottle - flow control
101 * @tty: terminal
102 *
103 * Indicate that a tty may continue transmitting data down the stack.
104 * Takes the termios rwsem to protect against parallel throttle/unthrottle
105 * and also to ensure the driver can consistently reference its own
106 * termios data at this point when implementing software flow control.
107 *
108 * Drivers should however remember that the stack can issue a throttle,
109 * then change flow control method, then unthrottle.
110 */
111
112void tty_unthrottle(struct tty_struct *tty)
113{
114 down_write(&tty->termios_rwsem);
115 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
116 tty->ops->unthrottle)
117 tty->ops->unthrottle(tty);
118 tty->flow_change = 0;
119 up_write(&tty->termios_rwsem);
120}
121EXPORT_SYMBOL(tty_unthrottle);
122
123/**
124 * tty_throttle_safe - flow control
125 * @tty: terminal
126 *
127 * Indicate that a tty should stop transmitting data down the stack.
128 * tty_throttle_safe will only attempt throttle if tty->flow_change is
129 * TTY_THROTTLE_SAFE. Prevents an accidental throttle due to race
130 * conditions when throttling is conditional on factors evaluated prior to
131 * throttling.
132 *
133 * Returns 0 if tty is throttled (or was already throttled)
134 */
135
136int tty_throttle_safe(struct tty_struct *tty)
137{
138 int ret = 0;
139
140 mutex_lock(&tty->throttle_mutex);
141 if (!tty_throttled(tty)) {
142 if (tty->flow_change != TTY_THROTTLE_SAFE)
143 ret = 1;
144 else {
145 set_bit(TTY_THROTTLED, &tty->flags);
146 if (tty->ops->throttle)
147 tty->ops->throttle(tty);
148 }
149 }
150 mutex_unlock(&tty->throttle_mutex);
151
152 return ret;
153}
154
155/**
156 * tty_unthrottle_safe - flow control
157 * @tty: terminal
158 *
159 * Similar to tty_unthrottle() but will only attempt unthrottle
160 * if tty->flow_change is TTY_UNTHROTTLE_SAFE. Prevents an accidental
161 * unthrottle due to race conditions when unthrottling is conditional
162 * on factors evaluated prior to unthrottling.
163 *
164 * Returns 0 if tty is unthrottled (or was already unthrottled)
165 */
166
167int tty_unthrottle_safe(struct tty_struct *tty)
168{
169 int ret = 0;
170
171 mutex_lock(&tty->throttle_mutex);
172 if (tty_throttled(tty)) {
173 if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
174 ret = 1;
175 else {
176 clear_bit(TTY_THROTTLED, &tty->flags);
177 if (tty->ops->unthrottle)
178 tty->ops->unthrottle(tty);
179 }
180 }
181 mutex_unlock(&tty->throttle_mutex);
182
183 return ret;
184}
185
186/**
187 * tty_wait_until_sent - wait for I/O to finish
188 * @tty: tty we are waiting for
189 * @timeout: how long we will wait
190 *
191 * Wait for characters pending in a tty driver to hit the wire, or
192 * for a timeout to occur (eg due to flow control)
193 *
194 * Locking: none
195 */
196
197void tty_wait_until_sent(struct tty_struct *tty, long timeout)
198{
199 tty_debug_wait_until_sent(tty, "wait until sent, timeout=%ld\n", timeout);
200
201 if (!timeout)
202 timeout = MAX_SCHEDULE_TIMEOUT;
203
204 timeout = wait_event_interruptible_timeout(tty->write_wait,
205 !tty_chars_in_buffer(tty), timeout);
206 if (timeout <= 0)
207 return;
208
209 if (timeout == MAX_SCHEDULE_TIMEOUT)
210 timeout = 0;
211
212 if (tty->ops->wait_until_sent)
213 tty->ops->wait_until_sent(tty, timeout);
214}
215EXPORT_SYMBOL(tty_wait_until_sent);
216
217
218/*
219 * Termios Helper Methods
220 */
221
222static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
223{
224 struct ktermios *termios = &tty->termios;
225 struct ktermios *locked = &tty->termios_locked;
226 int i;
227
228#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
229
230 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
231 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
232 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
233 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
234 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
235 for (i = 0; i < NCCS; i++)
236 termios->c_cc[i] = locked->c_cc[i] ?
237 old->c_cc[i] : termios->c_cc[i];
238 /* FIXME: What should we do for i/ospeed */
239}
240
241/**
242 * tty_termios_copy_hw - copy hardware settings
243 * @new: New termios
244 * @old: Old termios
245 *
246 * Propagate the hardware specific terminal setting bits from
247 * the old termios structure to the new one. This is used in cases
248 * where the hardware does not support reconfiguration or as a helper
249 * in some cases where only minimal reconfiguration is supported
250 */
251
252void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
253{
254 /* The bits a dumb device handles in software. Smart devices need
255 to always provide a set_termios method */
256 new->c_cflag &= HUPCL | CREAD | CLOCAL;
257 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
258 new->c_ispeed = old->c_ispeed;
259 new->c_ospeed = old->c_ospeed;
260}
261EXPORT_SYMBOL(tty_termios_copy_hw);
262
263/**
264 * tty_termios_hw_change - check for setting change
265 * @a: termios
266 * @b: termios to compare
267 *
268 * Check if any of the bits that affect a dumb device have changed
269 * between the two termios structures, or a speed change is needed.
270 */
271
272int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
273{
274 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
275 return 1;
276 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
277 return 1;
278 return 0;
279}
280EXPORT_SYMBOL(tty_termios_hw_change);
281
282/**
283 * tty_get_char_size - get size of a character
284 * @cflag: termios cflag value
285 *
286 * Get the size (in bits) of a character depending on @cflag's %CSIZE
287 * setting.
288 */
289unsigned char tty_get_char_size(unsigned int cflag)
290{
291 switch (cflag & CSIZE) {
292 case CS5:
293 return 5;
294 case CS6:
295 return 6;
296 case CS7:
297 return 7;
298 case CS8:
299 default:
300 return 8;
301 }
302}
303EXPORT_SYMBOL_GPL(tty_get_char_size);
304
305/**
306 * tty_get_frame_size - get size of a frame
307 * @cflag: termios cflag value
308 *
309 * Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB,
310 * and %PARENB setting. The result is a sum of character size, start and
311 * stop bits -- one bit each -- second stop bit (if set), and parity bit
312 * (if set).
313 */
314unsigned char tty_get_frame_size(unsigned int cflag)
315{
316 unsigned char bits = 2 + tty_get_char_size(cflag);
317
318 if (cflag & CSTOPB)
319 bits++;
320 if (cflag & PARENB)
321 bits++;
322
323 return bits;
324}
325EXPORT_SYMBOL_GPL(tty_get_frame_size);
326
327/**
328 * tty_set_termios - update termios values
329 * @tty: tty to update
330 * @new_termios: desired new value
331 *
332 * Perform updates to the termios values set on this terminal.
333 * A master pty's termios should never be set.
334 *
335 * Locking: termios_rwsem
336 */
337
338int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
339{
340 struct ktermios old_termios;
341 struct tty_ldisc *ld;
342
343 WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
344 tty->driver->subtype == PTY_TYPE_MASTER);
345 /*
346 * Perform the actual termios internal changes under lock.
347 */
348
349
350 /* FIXME: we need to decide on some locking/ordering semantics
351 for the set_termios notification eventually */
352 down_write(&tty->termios_rwsem);
353 old_termios = tty->termios;
354 tty->termios = *new_termios;
355 unset_locked_termios(tty, &old_termios);
356
357 if (tty->ops->set_termios)
358 tty->ops->set_termios(tty, &old_termios);
359 else
360 tty_termios_copy_hw(&tty->termios, &old_termios);
361
362 ld = tty_ldisc_ref(tty);
363 if (ld != NULL) {
364 if (ld->ops->set_termios)
365 ld->ops->set_termios(tty, &old_termios);
366 tty_ldisc_deref(ld);
367 }
368 up_write(&tty->termios_rwsem);
369 return 0;
370}
371EXPORT_SYMBOL_GPL(tty_set_termios);
372
373/**
374 * set_termios - set termios values for a tty
375 * @tty: terminal device
376 * @arg: user data
377 * @opt: option information
378 *
379 * Helper function to prepare termios data and run necessary other
380 * functions before using tty_set_termios to do the actual changes.
381 *
382 * Locking:
383 * Called functions take ldisc and termios_rwsem locks
384 */
385
386static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
387{
388 struct ktermios tmp_termios;
389 struct tty_ldisc *ld;
390 int retval = tty_check_change(tty);
391
392 if (retval)
393 return retval;
394
395 down_read(&tty->termios_rwsem);
396 tmp_termios = tty->termios;
397 up_read(&tty->termios_rwsem);
398
399 if (opt & TERMIOS_TERMIO) {
400 if (user_termio_to_kernel_termios(&tmp_termios,
401 (struct termio __user *)arg))
402 return -EFAULT;
403#ifdef TCGETS2
404 } else if (opt & TERMIOS_OLD) {
405 if (user_termios_to_kernel_termios_1(&tmp_termios,
406 (struct termios __user *)arg))
407 return -EFAULT;
408 } else {
409 if (user_termios_to_kernel_termios(&tmp_termios,
410 (struct termios2 __user *)arg))
411 return -EFAULT;
412 }
413#else
414 } else if (user_termios_to_kernel_termios(&tmp_termios,
415 (struct termios __user *)arg))
416 return -EFAULT;
417#endif
418
419 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
420 * with the real speed so its unconditionally usable */
421 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
422 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
423
424 ld = tty_ldisc_ref(tty);
425
426 if (ld != NULL) {
427 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
428 ld->ops->flush_buffer(tty);
429 tty_ldisc_deref(ld);
430 }
431
432 if (opt & TERMIOS_WAIT) {
433 tty_wait_until_sent(tty, 0);
434 if (signal_pending(current))
435 return -ERESTARTSYS;
436 }
437
438 tty_set_termios(tty, &tmp_termios);
439
440 /* FIXME: Arguably if tmp_termios == tty->termios AND the
441 actual requested termios was not tmp_termios then we may
442 want to return an error as no user requested change has
443 succeeded */
444 return 0;
445}
446
447static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
448{
449 down_read(&tty->termios_rwsem);
450 *kterm = tty->termios;
451 up_read(&tty->termios_rwsem);
452}
453
454static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
455{
456 down_read(&tty->termios_rwsem);
457 *kterm = tty->termios_locked;
458 up_read(&tty->termios_rwsem);
459}
460
461static int get_termio(struct tty_struct *tty, struct termio __user *termio)
462{
463 struct ktermios kterm;
464 copy_termios(tty, &kterm);
465 if (kernel_termios_to_user_termio(termio, &kterm))
466 return -EFAULT;
467 return 0;
468}
469
470#ifdef TIOCGETP
471/*
472 * These are deprecated, but there is limited support..
473 *
474 * The "sg_flags" translation is a joke..
475 */
476static int get_sgflags(struct tty_struct *tty)
477{
478 int flags = 0;
479
480 if (!L_ICANON(tty)) {
481 if (L_ISIG(tty))
482 flags |= 0x02; /* cbreak */
483 else
484 flags |= 0x20; /* raw */
485 }
486 if (L_ECHO(tty))
487 flags |= 0x08; /* echo */
488 if (O_OPOST(tty))
489 if (O_ONLCR(tty))
490 flags |= 0x10; /* crmod */
491 return flags;
492}
493
494static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
495{
496 struct sgttyb tmp;
497
498 down_read(&tty->termios_rwsem);
499 tmp.sg_ispeed = tty->termios.c_ispeed;
500 tmp.sg_ospeed = tty->termios.c_ospeed;
501 tmp.sg_erase = tty->termios.c_cc[VERASE];
502 tmp.sg_kill = tty->termios.c_cc[VKILL];
503 tmp.sg_flags = get_sgflags(tty);
504 up_read(&tty->termios_rwsem);
505
506 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
507}
508
509static void set_sgflags(struct ktermios *termios, int flags)
510{
511 termios->c_iflag = ICRNL | IXON;
512 termios->c_oflag = 0;
513 termios->c_lflag = ISIG | ICANON;
514 if (flags & 0x02) { /* cbreak */
515 termios->c_iflag = 0;
516 termios->c_lflag &= ~ICANON;
517 }
518 if (flags & 0x08) { /* echo */
519 termios->c_lflag |= ECHO | ECHOE | ECHOK |
520 ECHOCTL | ECHOKE | IEXTEN;
521 }
522 if (flags & 0x10) { /* crmod */
523 termios->c_oflag |= OPOST | ONLCR;
524 }
525 if (flags & 0x20) { /* raw */
526 termios->c_iflag = 0;
527 termios->c_lflag &= ~(ISIG | ICANON);
528 }
529 if (!(termios->c_lflag & ICANON)) {
530 termios->c_cc[VMIN] = 1;
531 termios->c_cc[VTIME] = 0;
532 }
533}
534
535/**
536 * set_sgttyb - set legacy terminal values
537 * @tty: tty structure
538 * @sgttyb: pointer to old style terminal structure
539 *
540 * Updates a terminal from the legacy BSD style terminal information
541 * structure.
542 *
543 * Locking: termios_rwsem
544 */
545
546static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
547{
548 int retval;
549 struct sgttyb tmp;
550 struct ktermios termios;
551
552 retval = tty_check_change(tty);
553 if (retval)
554 return retval;
555
556 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
557 return -EFAULT;
558
559 down_write(&tty->termios_rwsem);
560 termios = tty->termios;
561 termios.c_cc[VERASE] = tmp.sg_erase;
562 termios.c_cc[VKILL] = tmp.sg_kill;
563 set_sgflags(&termios, tmp.sg_flags);
564 /* Try and encode into Bfoo format */
565#ifdef BOTHER
566 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
567 termios.c_ospeed);
568#endif
569 up_write(&tty->termios_rwsem);
570 tty_set_termios(tty, &termios);
571 return 0;
572}
573#endif
574
575#ifdef TIOCGETC
576static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
577{
578 struct tchars tmp;
579
580 down_read(&tty->termios_rwsem);
581 tmp.t_intrc = tty->termios.c_cc[VINTR];
582 tmp.t_quitc = tty->termios.c_cc[VQUIT];
583 tmp.t_startc = tty->termios.c_cc[VSTART];
584 tmp.t_stopc = tty->termios.c_cc[VSTOP];
585 tmp.t_eofc = tty->termios.c_cc[VEOF];
586 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
587 up_read(&tty->termios_rwsem);
588 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
589}
590
591static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
592{
593 struct tchars tmp;
594
595 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
596 return -EFAULT;
597 down_write(&tty->termios_rwsem);
598 tty->termios.c_cc[VINTR] = tmp.t_intrc;
599 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
600 tty->termios.c_cc[VSTART] = tmp.t_startc;
601 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
602 tty->termios.c_cc[VEOF] = tmp.t_eofc;
603 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
604 up_write(&tty->termios_rwsem);
605 return 0;
606}
607#endif
608
609#ifdef TIOCGLTC
610static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
611{
612 struct ltchars tmp;
613
614 down_read(&tty->termios_rwsem);
615 tmp.t_suspc = tty->termios.c_cc[VSUSP];
616 /* what is dsuspc anyway? */
617 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
618 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
619 /* what is flushc anyway? */
620 tmp.t_flushc = tty->termios.c_cc[VEOL2];
621 tmp.t_werasc = tty->termios.c_cc[VWERASE];
622 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
623 up_read(&tty->termios_rwsem);
624 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
625}
626
627static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
628{
629 struct ltchars tmp;
630
631 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
632 return -EFAULT;
633
634 down_write(&tty->termios_rwsem);
635 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
636 /* what is dsuspc anyway? */
637 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
638 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
639 /* what is flushc anyway? */
640 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
641 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
642 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
643 up_write(&tty->termios_rwsem);
644 return 0;
645}
646#endif
647
648/**
649 * tty_change_softcar - carrier change ioctl helper
650 * @tty: tty to update
651 * @arg: enable/disable CLOCAL
652 *
653 * Perform a change to the CLOCAL state and call into the driver
654 * layer to make it visible. All done with the termios rwsem
655 */
656
657static int tty_change_softcar(struct tty_struct *tty, int arg)
658{
659 int ret = 0;
660 int bit = arg ? CLOCAL : 0;
661 struct ktermios old;
662
663 down_write(&tty->termios_rwsem);
664 old = tty->termios;
665 tty->termios.c_cflag &= ~CLOCAL;
666 tty->termios.c_cflag |= bit;
667 if (tty->ops->set_termios)
668 tty->ops->set_termios(tty, &old);
669 if (C_CLOCAL(tty) != bit)
670 ret = -EINVAL;
671 up_write(&tty->termios_rwsem);
672 return ret;
673}
674
675/**
676 * tty_mode_ioctl - mode related ioctls
677 * @tty: tty for the ioctl
678 * @file: file pointer for the tty
679 * @cmd: command
680 * @arg: ioctl argument
681 *
682 * Perform non line discipline specific mode control ioctls. This
683 * is designed to be called by line disciplines to ensure they provide
684 * consistent mode setting.
685 */
686
687int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
688 unsigned int cmd, unsigned long arg)
689{
690 struct tty_struct *real_tty;
691 void __user *p = (void __user *)arg;
692 int ret = 0;
693 struct ktermios kterm;
694
695 BUG_ON(file == NULL);
696
697 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
698 tty->driver->subtype == PTY_TYPE_MASTER)
699 real_tty = tty->link;
700 else
701 real_tty = tty;
702
703 switch (cmd) {
704#ifdef TIOCGETP
705 case TIOCGETP:
706 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
707 case TIOCSETP:
708 case TIOCSETN:
709 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
710#endif
711#ifdef TIOCGETC
712 case TIOCGETC:
713 return get_tchars(real_tty, p);
714 case TIOCSETC:
715 return set_tchars(real_tty, p);
716#endif
717#ifdef TIOCGLTC
718 case TIOCGLTC:
719 return get_ltchars(real_tty, p);
720 case TIOCSLTC:
721 return set_ltchars(real_tty, p);
722#endif
723 case TCSETSF:
724 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
725 case TCSETSW:
726 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
727 case TCSETS:
728 return set_termios(real_tty, p, TERMIOS_OLD);
729#ifndef TCGETS2
730 case TCGETS:
731 copy_termios(real_tty, &kterm);
732 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
733 ret = -EFAULT;
734 return ret;
735#else
736 case TCGETS:
737 copy_termios(real_tty, &kterm);
738 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
739 ret = -EFAULT;
740 return ret;
741 case TCGETS2:
742 copy_termios(real_tty, &kterm);
743 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
744 ret = -EFAULT;
745 return ret;
746 case TCSETSF2:
747 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
748 case TCSETSW2:
749 return set_termios(real_tty, p, TERMIOS_WAIT);
750 case TCSETS2:
751 return set_termios(real_tty, p, 0);
752#endif
753 case TCGETA:
754 return get_termio(real_tty, p);
755 case TCSETAF:
756 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
757 case TCSETAW:
758 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
759 case TCSETA:
760 return set_termios(real_tty, p, TERMIOS_TERMIO);
761#ifndef TCGETS2
762 case TIOCGLCKTRMIOS:
763 copy_termios_locked(real_tty, &kterm);
764 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
765 ret = -EFAULT;
766 return ret;
767 case TIOCSLCKTRMIOS:
768 if (!capable(CAP_SYS_ADMIN))
769 return -EPERM;
770 copy_termios_locked(real_tty, &kterm);
771 if (user_termios_to_kernel_termios(&kterm,
772 (struct termios __user *) arg))
773 return -EFAULT;
774 down_write(&real_tty->termios_rwsem);
775 real_tty->termios_locked = kterm;
776 up_write(&real_tty->termios_rwsem);
777 return 0;
778#else
779 case TIOCGLCKTRMIOS:
780 copy_termios_locked(real_tty, &kterm);
781 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
782 ret = -EFAULT;
783 return ret;
784 case TIOCSLCKTRMIOS:
785 if (!capable(CAP_SYS_ADMIN))
786 return -EPERM;
787 copy_termios_locked(real_tty, &kterm);
788 if (user_termios_to_kernel_termios_1(&kterm,
789 (struct termios __user *) arg))
790 return -EFAULT;
791 down_write(&real_tty->termios_rwsem);
792 real_tty->termios_locked = kterm;
793 up_write(&real_tty->termios_rwsem);
794 return ret;
795#endif
796#ifdef TCGETX
797 case TCGETX:
798 case TCSETX:
799 case TCSETXW:
800 case TCSETXF:
801 return -ENOTTY;
802#endif
803 case TIOCGSOFTCAR:
804 copy_termios(real_tty, &kterm);
805 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
806 (int __user *)arg);
807 return ret;
808 case TIOCSSOFTCAR:
809 if (get_user(arg, (unsigned int __user *) arg))
810 return -EFAULT;
811 return tty_change_softcar(real_tty, arg);
812 default:
813 return -ENOIOCTLCMD;
814 }
815}
816EXPORT_SYMBOL_GPL(tty_mode_ioctl);
817
818
819/* Caller guarantees ldisc reference is held */
820static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
821{
822 struct tty_ldisc *ld = tty->ldisc;
823
824 switch (arg) {
825 case TCIFLUSH:
826 if (ld && ld->ops->flush_buffer) {
827 ld->ops->flush_buffer(tty);
828 tty_unthrottle(tty);
829 }
830 break;
831 case TCIOFLUSH:
832 if (ld && ld->ops->flush_buffer) {
833 ld->ops->flush_buffer(tty);
834 tty_unthrottle(tty);
835 }
836 fallthrough;
837 case TCOFLUSH:
838 tty_driver_flush_buffer(tty);
839 break;
840 default:
841 return -EINVAL;
842 }
843 return 0;
844}
845
846int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
847{
848 struct tty_ldisc *ld;
849 int retval = tty_check_change(tty);
850 if (retval)
851 return retval;
852
853 ld = tty_ldisc_ref_wait(tty);
854 retval = __tty_perform_flush(tty, arg);
855 if (ld)
856 tty_ldisc_deref(ld);
857 return retval;
858}
859EXPORT_SYMBOL_GPL(tty_perform_flush);
860
861int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
862 unsigned int cmd, unsigned long arg)
863{
864 int retval;
865
866 switch (cmd) {
867 case TCXONC:
868 retval = tty_check_change(tty);
869 if (retval)
870 return retval;
871 switch (arg) {
872 case TCOOFF:
873 spin_lock_irq(&tty->flow.lock);
874 if (!tty->flow.tco_stopped) {
875 tty->flow.tco_stopped = true;
876 __stop_tty(tty);
877 }
878 spin_unlock_irq(&tty->flow.lock);
879 break;
880 case TCOON:
881 spin_lock_irq(&tty->flow.lock);
882 if (tty->flow.tco_stopped) {
883 tty->flow.tco_stopped = false;
884 __start_tty(tty);
885 }
886 spin_unlock_irq(&tty->flow.lock);
887 break;
888 case TCIOFF:
889 if (STOP_CHAR(tty) != __DISABLED_CHAR)
890 retval = tty_send_xchar(tty, STOP_CHAR(tty));
891 break;
892 case TCION:
893 if (START_CHAR(tty) != __DISABLED_CHAR)
894 retval = tty_send_xchar(tty, START_CHAR(tty));
895 break;
896 default:
897 return -EINVAL;
898 }
899 return retval;
900 case TCFLSH:
901 retval = tty_check_change(tty);
902 if (retval)
903 return retval;
904 return __tty_perform_flush(tty, arg);
905 default:
906 /* Try the mode commands */
907 return tty_mode_ioctl(tty, file, cmd, arg);
908 }
909}
910EXPORT_SYMBOL(n_tty_ioctl_helper);