Loading...
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/bits.h>
11#include <linux/types.h>
12#include <linux/termios.h>
13#include <linux/errno.h>
14#include <linux/sched/signal.h>
15#include <linux/kernel.h>
16#include <linux/major.h>
17#include <linux/tty.h>
18#include <linux/fcntl.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/module.h>
22#include <linux/bitops.h>
23#include <linux/mutex.h>
24#include <linux/compat.h>
25#include <linux/termios_internal.h>
26#include "tty.h"
27
28#include <asm/io.h>
29#include <linux/uaccess.h>
30
31#undef DEBUG
32
33/*
34 * Internal flag options for termios setting behavior
35 */
36#define TERMIOS_FLUSH BIT(0)
37#define TERMIOS_WAIT BIT(1)
38#define TERMIOS_TERMIO BIT(2)
39#define TERMIOS_OLD BIT(3)
40
41/**
42 * tty_chars_in_buffer - characters pending
43 * @tty: terminal
44 *
45 * Returns: the number of bytes of data in the device private output queue. If
46 * no private method is supplied there is assumed to be no queue on the device.
47 */
48unsigned int tty_chars_in_buffer(struct tty_struct *tty)
49{
50 if (tty->ops->chars_in_buffer)
51 return tty->ops->chars_in_buffer(tty);
52 return 0;
53}
54EXPORT_SYMBOL(tty_chars_in_buffer);
55
56/**
57 * tty_write_room - write queue space
58 * @tty: terminal
59 *
60 * Returns: the number of bytes that can be queued to this device at the present
61 * time. The result should be treated as a guarantee and the driver cannot
62 * offer a value it later shrinks by more than the number of bytes written. If
63 * no method is provided, 2K is always returned and data may be lost as there
64 * will be no flow control.
65 */
66unsigned int tty_write_room(struct tty_struct *tty)
67{
68 if (tty->ops->write_room)
69 return tty->ops->write_room(tty);
70 return 2048;
71}
72EXPORT_SYMBOL(tty_write_room);
73
74/**
75 * tty_driver_flush_buffer - discard internal buffer
76 * @tty: terminal
77 *
78 * Discard the internal output buffer for this device. If no method is provided,
79 * then either the buffer cannot be hardware flushed or there is no buffer
80 * driver side.
81 */
82void tty_driver_flush_buffer(struct tty_struct *tty)
83{
84 if (tty->ops->flush_buffer)
85 tty->ops->flush_buffer(tty);
86}
87EXPORT_SYMBOL(tty_driver_flush_buffer);
88
89/**
90 * tty_unthrottle - flow control
91 * @tty: terminal
92 *
93 * Indicate that a @tty may continue transmitting data down the stack. Takes
94 * the &tty_struct->termios_rwsem to protect against parallel
95 * throttle/unthrottle and also to ensure the driver can consistently reference
96 * its own termios data at this point when implementing software flow control.
97 *
98 * Drivers should however remember that the stack can issue a throttle, then
99 * change flow control method, then unthrottle.
100 */
101void tty_unthrottle(struct tty_struct *tty)
102{
103 down_write(&tty->termios_rwsem);
104 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
105 tty->ops->unthrottle)
106 tty->ops->unthrottle(tty);
107 tty->flow_change = TTY_FLOW_NO_CHANGE;
108 up_write(&tty->termios_rwsem);
109}
110EXPORT_SYMBOL(tty_unthrottle);
111
112/**
113 * tty_throttle_safe - flow control
114 * @tty: terminal
115 *
116 * Indicate that a @tty should stop transmitting data down the stack.
117 * tty_throttle_safe() will only attempt throttle if @tty->flow_change is
118 * %TTY_THROTTLE_SAFE. Prevents an accidental throttle due to race conditions
119 * when throttling is conditional on factors evaluated prior to throttling.
120 *
121 * Returns: %true if @tty is throttled (or was already throttled)
122 */
123bool tty_throttle_safe(struct tty_struct *tty)
124{
125 bool ret = true;
126
127 mutex_lock(&tty->throttle_mutex);
128 if (!tty_throttled(tty)) {
129 if (tty->flow_change != TTY_THROTTLE_SAFE)
130 ret = false;
131 else {
132 set_bit(TTY_THROTTLED, &tty->flags);
133 if (tty->ops->throttle)
134 tty->ops->throttle(tty);
135 }
136 }
137 mutex_unlock(&tty->throttle_mutex);
138
139 return ret;
140}
141
142/**
143 * tty_unthrottle_safe - flow control
144 * @tty: terminal
145 *
146 * Similar to tty_unthrottle() but will only attempt unthrottle if
147 * @tty->flow_change is %TTY_UNTHROTTLE_SAFE. Prevents an accidental unthrottle
148 * due to race conditions when unthrottling is conditional on factors evaluated
149 * prior to unthrottling.
150 *
151 * Returns: %true if @tty is unthrottled (or was already unthrottled)
152 */
153bool tty_unthrottle_safe(struct tty_struct *tty)
154{
155 bool ret = true;
156
157 mutex_lock(&tty->throttle_mutex);
158 if (tty_throttled(tty)) {
159 if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
160 ret = false;
161 else {
162 clear_bit(TTY_THROTTLED, &tty->flags);
163 if (tty->ops->unthrottle)
164 tty->ops->unthrottle(tty);
165 }
166 }
167 mutex_unlock(&tty->throttle_mutex);
168
169 return ret;
170}
171
172/**
173 * tty_wait_until_sent - wait for I/O to finish
174 * @tty: tty we are waiting for
175 * @timeout: how long we will wait
176 *
177 * Wait for characters pending in a tty driver to hit the wire, or for a
178 * timeout to occur (eg due to flow control).
179 *
180 * Locking: none
181 */
182
183void tty_wait_until_sent(struct tty_struct *tty, long timeout)
184{
185 if (!timeout)
186 timeout = MAX_SCHEDULE_TIMEOUT;
187
188 timeout = wait_event_interruptible_timeout(tty->write_wait,
189 !tty_chars_in_buffer(tty), timeout);
190 if (timeout <= 0)
191 return;
192
193 if (timeout == MAX_SCHEDULE_TIMEOUT)
194 timeout = 0;
195
196 if (tty->ops->wait_until_sent)
197 tty->ops->wait_until_sent(tty, timeout);
198}
199EXPORT_SYMBOL(tty_wait_until_sent);
200
201
202/*
203 * Termios Helper Methods
204 */
205
206static void unset_locked_termios(struct tty_struct *tty, const struct ktermios *old)
207{
208 struct ktermios *termios = &tty->termios;
209 struct ktermios *locked = &tty->termios_locked;
210 int i;
211
212#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
213
214 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
215 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
216 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
217 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
218 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
219 for (i = 0; i < NCCS; i++)
220 termios->c_cc[i] = locked->c_cc[i] ?
221 old->c_cc[i] : termios->c_cc[i];
222 /* FIXME: What should we do for i/ospeed */
223}
224
225/**
226 * tty_termios_copy_hw - copy hardware settings
227 * @new: new termios
228 * @old: old termios
229 *
230 * Propagate the hardware specific terminal setting bits from the @old termios
231 * structure to the @new one. This is used in cases where the hardware does not
232 * support reconfiguration or as a helper in some cases where only minimal
233 * reconfiguration is supported.
234 */
235void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old)
236{
237 /* The bits a dumb device handles in software. Smart devices need
238 to always provide a set_termios method */
239 new->c_cflag &= HUPCL | CREAD | CLOCAL;
240 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
241 new->c_ispeed = old->c_ispeed;
242 new->c_ospeed = old->c_ospeed;
243}
244EXPORT_SYMBOL(tty_termios_copy_hw);
245
246/**
247 * tty_termios_hw_change - check for setting change
248 * @a: termios
249 * @b: termios to compare
250 *
251 * Check if any of the bits that affect a dumb device have changed between the
252 * two termios structures, or a speed change is needed.
253 *
254 * Returns: %true if change is needed
255 */
256bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
257{
258 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
259 return true;
260 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
261 return true;
262 return false;
263}
264EXPORT_SYMBOL(tty_termios_hw_change);
265
266/**
267 * tty_get_char_size - get size of a character
268 * @cflag: termios cflag value
269 *
270 * Returns: size (in bits) of a character depending on @cflag's %CSIZE setting
271 */
272unsigned char tty_get_char_size(unsigned int cflag)
273{
274 switch (cflag & CSIZE) {
275 case CS5:
276 return 5;
277 case CS6:
278 return 6;
279 case CS7:
280 return 7;
281 case CS8:
282 default:
283 return 8;
284 }
285}
286EXPORT_SYMBOL_GPL(tty_get_char_size);
287
288/**
289 * tty_get_frame_size - get size of a frame
290 * @cflag: termios cflag value
291 *
292 * Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB, and
293 * %PARENB setting. The result is a sum of character size, start and stop bits
294 * -- one bit each -- second stop bit (if set), and parity bit (if set).
295 *
296 * Returns: size (in bits) of a frame depending on @cflag's setting.
297 */
298unsigned char tty_get_frame_size(unsigned int cflag)
299{
300 unsigned char bits = 2 + tty_get_char_size(cflag);
301
302 if (cflag & CSTOPB)
303 bits++;
304 if (cflag & PARENB)
305 bits++;
306 if (cflag & ADDRB)
307 bits++;
308
309 return bits;
310}
311EXPORT_SYMBOL_GPL(tty_get_frame_size);
312
313/**
314 * tty_set_termios - update termios values
315 * @tty: tty to update
316 * @new_termios: desired new value
317 *
318 * Perform updates to the termios values set on this @tty. A master pty's
319 * termios should never be set.
320 *
321 * Locking: &tty_struct->termios_rwsem
322 */
323int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
324{
325 struct ktermios old_termios;
326 struct tty_ldisc *ld;
327
328 WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
329 tty->driver->subtype == PTY_TYPE_MASTER);
330 /*
331 * Perform the actual termios internal changes under lock.
332 */
333
334
335 /* FIXME: we need to decide on some locking/ordering semantics
336 for the set_termios notification eventually */
337 down_write(&tty->termios_rwsem);
338 old_termios = tty->termios;
339 tty->termios = *new_termios;
340 unset_locked_termios(tty, &old_termios);
341 /* Reset any ADDRB changes, ADDRB is changed through ->rs485_config() */
342 tty->termios.c_cflag ^= (tty->termios.c_cflag ^ old_termios.c_cflag) & ADDRB;
343
344 if (tty->ops->set_termios)
345 tty->ops->set_termios(tty, &old_termios);
346 else
347 tty_termios_copy_hw(&tty->termios, &old_termios);
348
349 ld = tty_ldisc_ref(tty);
350 if (ld != NULL) {
351 if (ld->ops->set_termios)
352 ld->ops->set_termios(tty, &old_termios);
353 tty_ldisc_deref(ld);
354 }
355 up_write(&tty->termios_rwsem);
356 return 0;
357}
358EXPORT_SYMBOL_GPL(tty_set_termios);
359
360
361/*
362 * Translate a "termio" structure into a "termios". Ugh.
363 */
364__weak int user_termio_to_kernel_termios(struct ktermios *termios,
365 struct termio __user *termio)
366{
367 struct termio v;
368
369 if (copy_from_user(&v, termio, sizeof(struct termio)))
370 return -EFAULT;
371
372 termios->c_iflag = (0xffff0000 & termios->c_iflag) | v.c_iflag;
373 termios->c_oflag = (0xffff0000 & termios->c_oflag) | v.c_oflag;
374 termios->c_cflag = (0xffff0000 & termios->c_cflag) | v.c_cflag;
375 termios->c_lflag = (0xffff0000 & termios->c_lflag) | v.c_lflag;
376 termios->c_line = (0xffff0000 & termios->c_lflag) | v.c_line;
377 memcpy(termios->c_cc, v.c_cc, NCC);
378 return 0;
379}
380
381/*
382 * Translate a "termios" structure into a "termio". Ugh.
383 */
384__weak int kernel_termios_to_user_termio(struct termio __user *termio,
385 struct ktermios *termios)
386{
387 struct termio v;
388 memset(&v, 0, sizeof(struct termio));
389 v.c_iflag = termios->c_iflag;
390 v.c_oflag = termios->c_oflag;
391 v.c_cflag = termios->c_cflag;
392 v.c_lflag = termios->c_lflag;
393 v.c_line = termios->c_line;
394 memcpy(v.c_cc, termios->c_cc, NCC);
395 return copy_to_user(termio, &v, sizeof(struct termio));
396}
397
398#ifdef TCGETS2
399__weak int user_termios_to_kernel_termios(struct ktermios *k,
400 struct termios2 __user *u)
401{
402 return copy_from_user(k, u, sizeof(struct termios2));
403}
404__weak int kernel_termios_to_user_termios(struct termios2 __user *u,
405 struct ktermios *k)
406{
407 return copy_to_user(u, k, sizeof(struct termios2));
408}
409__weak int user_termios_to_kernel_termios_1(struct ktermios *k,
410 struct termios __user *u)
411{
412 return copy_from_user(k, u, sizeof(struct termios));
413}
414__weak int kernel_termios_to_user_termios_1(struct termios __user *u,
415 struct ktermios *k)
416{
417 return copy_to_user(u, k, sizeof(struct termios));
418}
419
420#else
421
422__weak int user_termios_to_kernel_termios(struct ktermios *k,
423 struct termios __user *u)
424{
425 return copy_from_user(k, u, sizeof(struct termios));
426}
427__weak int kernel_termios_to_user_termios(struct termios __user *u,
428 struct ktermios *k)
429{
430 return copy_to_user(u, k, sizeof(struct termios));
431}
432#endif /* TCGETS2 */
433
434/**
435 * set_termios - set termios values for a tty
436 * @tty: terminal device
437 * @arg: user data
438 * @opt: option information
439 *
440 * Helper function to prepare termios data and run necessary other functions
441 * before using tty_set_termios() to do the actual changes.
442 *
443 * Locking: called functions take &tty_struct->ldisc_sem and
444 * &tty_struct->termios_rwsem locks
445 *
446 * Returns: 0 on success, an error otherwise
447 */
448static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
449{
450 struct ktermios tmp_termios;
451 struct tty_ldisc *ld;
452 int retval = tty_check_change(tty);
453
454 if (retval)
455 return retval;
456
457 down_read(&tty->termios_rwsem);
458 tmp_termios = tty->termios;
459 up_read(&tty->termios_rwsem);
460
461 if (opt & TERMIOS_TERMIO) {
462 if (user_termio_to_kernel_termios(&tmp_termios,
463 (struct termio __user *)arg))
464 return -EFAULT;
465#ifdef TCGETS2
466 } else if (opt & TERMIOS_OLD) {
467 if (user_termios_to_kernel_termios_1(&tmp_termios,
468 (struct termios __user *)arg))
469 return -EFAULT;
470 } else {
471 if (user_termios_to_kernel_termios(&tmp_termios,
472 (struct termios2 __user *)arg))
473 return -EFAULT;
474 }
475#else
476 } else if (user_termios_to_kernel_termios(&tmp_termios,
477 (struct termios __user *)arg))
478 return -EFAULT;
479#endif
480
481 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
482 * with the real speed so its unconditionally usable */
483 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
484 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
485
486 if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) {
487retry_write_wait:
488 retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty));
489 if (retval < 0)
490 return retval;
491
492 if (tty_write_lock(tty, false) < 0)
493 goto retry_write_wait;
494
495 /* Racing writer? */
496 if (tty_chars_in_buffer(tty)) {
497 tty_write_unlock(tty);
498 goto retry_write_wait;
499 }
500
501 ld = tty_ldisc_ref(tty);
502 if (ld != NULL) {
503 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
504 ld->ops->flush_buffer(tty);
505 tty_ldisc_deref(ld);
506 }
507
508 if ((opt & TERMIOS_WAIT) && tty->ops->wait_until_sent) {
509 tty->ops->wait_until_sent(tty, 0);
510 if (signal_pending(current)) {
511 tty_write_unlock(tty);
512 return -ERESTARTSYS;
513 }
514 }
515
516 tty_set_termios(tty, &tmp_termios);
517
518 tty_write_unlock(tty);
519 } else {
520 tty_set_termios(tty, &tmp_termios);
521 }
522
523 /* FIXME: Arguably if tmp_termios == tty->termios AND the
524 actual requested termios was not tmp_termios then we may
525 want to return an error as no user requested change has
526 succeeded */
527 return 0;
528}
529
530static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
531{
532 down_read(&tty->termios_rwsem);
533 *kterm = tty->termios;
534 up_read(&tty->termios_rwsem);
535}
536
537static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
538{
539 down_read(&tty->termios_rwsem);
540 *kterm = tty->termios_locked;
541 up_read(&tty->termios_rwsem);
542}
543
544static int get_termio(struct tty_struct *tty, struct termio __user *termio)
545{
546 struct ktermios kterm;
547 copy_termios(tty, &kterm);
548 if (kernel_termios_to_user_termio(termio, &kterm))
549 return -EFAULT;
550 return 0;
551}
552
553#ifdef TIOCGETP
554/*
555 * These are deprecated, but there is limited support..
556 *
557 * The "sg_flags" translation is a joke..
558 */
559static int get_sgflags(struct tty_struct *tty)
560{
561 int flags = 0;
562
563 if (!L_ICANON(tty)) {
564 if (L_ISIG(tty))
565 flags |= 0x02; /* cbreak */
566 else
567 flags |= 0x20; /* raw */
568 }
569 if (L_ECHO(tty))
570 flags |= 0x08; /* echo */
571 if (O_OPOST(tty))
572 if (O_ONLCR(tty))
573 flags |= 0x10; /* crmod */
574 return flags;
575}
576
577static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
578{
579 struct sgttyb tmp;
580
581 down_read(&tty->termios_rwsem);
582 tmp.sg_ispeed = tty->termios.c_ispeed;
583 tmp.sg_ospeed = tty->termios.c_ospeed;
584 tmp.sg_erase = tty->termios.c_cc[VERASE];
585 tmp.sg_kill = tty->termios.c_cc[VKILL];
586 tmp.sg_flags = get_sgflags(tty);
587 up_read(&tty->termios_rwsem);
588
589 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
590}
591
592static void set_sgflags(struct ktermios *termios, int flags)
593{
594 termios->c_iflag = ICRNL | IXON;
595 termios->c_oflag = 0;
596 termios->c_lflag = ISIG | ICANON;
597 if (flags & 0x02) { /* cbreak */
598 termios->c_iflag = 0;
599 termios->c_lflag &= ~ICANON;
600 }
601 if (flags & 0x08) { /* echo */
602 termios->c_lflag |= ECHO | ECHOE | ECHOK |
603 ECHOCTL | ECHOKE | IEXTEN;
604 }
605 if (flags & 0x10) { /* crmod */
606 termios->c_oflag |= OPOST | ONLCR;
607 }
608 if (flags & 0x20) { /* raw */
609 termios->c_iflag = 0;
610 termios->c_lflag &= ~(ISIG | ICANON);
611 }
612 if (!(termios->c_lflag & ICANON)) {
613 termios->c_cc[VMIN] = 1;
614 termios->c_cc[VTIME] = 0;
615 }
616}
617
618/**
619 * set_sgttyb - set legacy terminal values
620 * @tty: tty structure
621 * @sgttyb: pointer to old style terminal structure
622 *
623 * Updates a terminal from the legacy BSD style terminal information structure.
624 *
625 * Locking: &tty_struct->termios_rwsem
626 *
627 * Returns: 0 on success, an error otherwise
628 */
629static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
630{
631 int retval;
632 struct sgttyb tmp;
633 struct ktermios termios;
634
635 retval = tty_check_change(tty);
636 if (retval)
637 return retval;
638
639 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
640 return -EFAULT;
641
642 down_write(&tty->termios_rwsem);
643 termios = tty->termios;
644 termios.c_cc[VERASE] = tmp.sg_erase;
645 termios.c_cc[VKILL] = tmp.sg_kill;
646 set_sgflags(&termios, tmp.sg_flags);
647 /* Try and encode into Bfoo format */
648 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
649 termios.c_ospeed);
650 up_write(&tty->termios_rwsem);
651 tty_set_termios(tty, &termios);
652 return 0;
653}
654#endif
655
656#ifdef TIOCGETC
657static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
658{
659 struct tchars tmp;
660
661 down_read(&tty->termios_rwsem);
662 tmp.t_intrc = tty->termios.c_cc[VINTR];
663 tmp.t_quitc = tty->termios.c_cc[VQUIT];
664 tmp.t_startc = tty->termios.c_cc[VSTART];
665 tmp.t_stopc = tty->termios.c_cc[VSTOP];
666 tmp.t_eofc = tty->termios.c_cc[VEOF];
667 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
668 up_read(&tty->termios_rwsem);
669 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
670}
671
672static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
673{
674 struct tchars tmp;
675
676 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
677 return -EFAULT;
678 down_write(&tty->termios_rwsem);
679 tty->termios.c_cc[VINTR] = tmp.t_intrc;
680 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
681 tty->termios.c_cc[VSTART] = tmp.t_startc;
682 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
683 tty->termios.c_cc[VEOF] = tmp.t_eofc;
684 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
685 up_write(&tty->termios_rwsem);
686 return 0;
687}
688#endif
689
690#ifdef TIOCGLTC
691static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
692{
693 struct ltchars tmp;
694
695 down_read(&tty->termios_rwsem);
696 tmp.t_suspc = tty->termios.c_cc[VSUSP];
697 /* what is dsuspc anyway? */
698 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
699 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
700 /* what is flushc anyway? */
701 tmp.t_flushc = tty->termios.c_cc[VEOL2];
702 tmp.t_werasc = tty->termios.c_cc[VWERASE];
703 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
704 up_read(&tty->termios_rwsem);
705 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
706}
707
708static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
709{
710 struct ltchars tmp;
711
712 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
713 return -EFAULT;
714
715 down_write(&tty->termios_rwsem);
716 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
717 /* what is dsuspc anyway? */
718 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
719 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
720 /* what is flushc anyway? */
721 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
722 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
723 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
724 up_write(&tty->termios_rwsem);
725 return 0;
726}
727#endif
728
729/**
730 * tty_change_softcar - carrier change ioctl helper
731 * @tty: tty to update
732 * @enable: enable/disable %CLOCAL
733 *
734 * Perform a change to the %CLOCAL state and call into the driver layer to make
735 * it visible.
736 *
737 * Locking: &tty_struct->termios_rwsem.
738 *
739 * Returns: 0 on success, an error otherwise
740 */
741static int tty_change_softcar(struct tty_struct *tty, bool enable)
742{
743 int ret = 0;
744 struct ktermios old;
745 tcflag_t bit = enable ? CLOCAL : 0;
746
747 down_write(&tty->termios_rwsem);
748 old = tty->termios;
749 tty->termios.c_cflag &= ~CLOCAL;
750 tty->termios.c_cflag |= bit;
751 if (tty->ops->set_termios)
752 tty->ops->set_termios(tty, &old);
753 if (C_CLOCAL(tty) != bit)
754 ret = -EINVAL;
755 up_write(&tty->termios_rwsem);
756 return ret;
757}
758
759/**
760 * tty_mode_ioctl - mode related ioctls
761 * @tty: tty for the ioctl
762 * @cmd: command
763 * @arg: ioctl argument
764 *
765 * Perform non-line discipline specific mode control ioctls. This is designed
766 * to be called by line disciplines to ensure they provide consistent mode
767 * setting.
768 */
769int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
770{
771 struct tty_struct *real_tty;
772 void __user *p = (void __user *)arg;
773 int ret = 0;
774 struct ktermios kterm;
775
776 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
777 tty->driver->subtype == PTY_TYPE_MASTER)
778 real_tty = tty->link;
779 else
780 real_tty = tty;
781
782 switch (cmd) {
783#ifdef TIOCGETP
784 case TIOCGETP:
785 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
786 case TIOCSETP:
787 case TIOCSETN:
788 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
789#endif
790#ifdef TIOCGETC
791 case TIOCGETC:
792 return get_tchars(real_tty, p);
793 case TIOCSETC:
794 return set_tchars(real_tty, p);
795#endif
796#ifdef TIOCGLTC
797 case TIOCGLTC:
798 return get_ltchars(real_tty, p);
799 case TIOCSLTC:
800 return set_ltchars(real_tty, p);
801#endif
802 case TCSETSF:
803 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
804 case TCSETSW:
805 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
806 case TCSETS:
807 return set_termios(real_tty, p, TERMIOS_OLD);
808#ifndef TCGETS2
809 case TCGETS:
810 copy_termios(real_tty, &kterm);
811 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
812 ret = -EFAULT;
813 return ret;
814#else
815 case TCGETS:
816 copy_termios(real_tty, &kterm);
817 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
818 ret = -EFAULT;
819 return ret;
820 case TCGETS2:
821 copy_termios(real_tty, &kterm);
822 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
823 ret = -EFAULT;
824 return ret;
825 case TCSETSF2:
826 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
827 case TCSETSW2:
828 return set_termios(real_tty, p, TERMIOS_WAIT);
829 case TCSETS2:
830 return set_termios(real_tty, p, 0);
831#endif
832 case TCGETA:
833 return get_termio(real_tty, p);
834 case TCSETAF:
835 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
836 case TCSETAW:
837 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
838 case TCSETA:
839 return set_termios(real_tty, p, TERMIOS_TERMIO);
840#ifndef TCGETS2
841 case TIOCGLCKTRMIOS:
842 copy_termios_locked(real_tty, &kterm);
843 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
844 ret = -EFAULT;
845 return ret;
846 case TIOCSLCKTRMIOS:
847 if (!checkpoint_restore_ns_capable(&init_user_ns))
848 return -EPERM;
849 copy_termios_locked(real_tty, &kterm);
850 if (user_termios_to_kernel_termios(&kterm,
851 (struct termios __user *) arg))
852 return -EFAULT;
853 down_write(&real_tty->termios_rwsem);
854 real_tty->termios_locked = kterm;
855 up_write(&real_tty->termios_rwsem);
856 return 0;
857#else
858 case TIOCGLCKTRMIOS:
859 copy_termios_locked(real_tty, &kterm);
860 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
861 ret = -EFAULT;
862 return ret;
863 case TIOCSLCKTRMIOS:
864 if (!checkpoint_restore_ns_capable(&init_user_ns))
865 return -EPERM;
866 copy_termios_locked(real_tty, &kterm);
867 if (user_termios_to_kernel_termios_1(&kterm,
868 (struct termios __user *) arg))
869 return -EFAULT;
870 down_write(&real_tty->termios_rwsem);
871 real_tty->termios_locked = kterm;
872 up_write(&real_tty->termios_rwsem);
873 return ret;
874#endif
875#ifdef TCGETX
876 case TCGETX:
877 case TCSETX:
878 case TCSETXW:
879 case TCSETXF:
880 return -ENOTTY;
881#endif
882 case TIOCGSOFTCAR:
883 copy_termios(real_tty, &kterm);
884 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
885 (int __user *)arg);
886 return ret;
887 case TIOCSSOFTCAR:
888 if (get_user(arg, (unsigned int __user *) arg))
889 return -EFAULT;
890 return tty_change_softcar(real_tty, arg);
891 default:
892 return -ENOIOCTLCMD;
893 }
894}
895EXPORT_SYMBOL_GPL(tty_mode_ioctl);
896
897
898/* Caller guarantees ldisc reference is held */
899static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
900{
901 struct tty_ldisc *ld = tty->ldisc;
902
903 switch (arg) {
904 case TCIFLUSH:
905 if (ld && ld->ops->flush_buffer) {
906 ld->ops->flush_buffer(tty);
907 tty_unthrottle(tty);
908 }
909 break;
910 case TCIOFLUSH:
911 if (ld && ld->ops->flush_buffer) {
912 ld->ops->flush_buffer(tty);
913 tty_unthrottle(tty);
914 }
915 fallthrough;
916 case TCOFLUSH:
917 tty_driver_flush_buffer(tty);
918 break;
919 default:
920 return -EINVAL;
921 }
922 return 0;
923}
924
925int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
926{
927 struct tty_ldisc *ld;
928 int retval = tty_check_change(tty);
929 if (retval)
930 return retval;
931
932 ld = tty_ldisc_ref_wait(tty);
933 retval = __tty_perform_flush(tty, arg);
934 if (ld)
935 tty_ldisc_deref(ld);
936 return retval;
937}
938EXPORT_SYMBOL_GPL(tty_perform_flush);
939
940int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
941 unsigned long arg)
942{
943 int retval;
944
945 switch (cmd) {
946 case TCXONC:
947 retval = tty_check_change(tty);
948 if (retval)
949 return retval;
950 switch (arg) {
951 case TCOOFF:
952 spin_lock_irq(&tty->flow.lock);
953 if (!tty->flow.tco_stopped) {
954 tty->flow.tco_stopped = true;
955 __stop_tty(tty);
956 }
957 spin_unlock_irq(&tty->flow.lock);
958 break;
959 case TCOON:
960 spin_lock_irq(&tty->flow.lock);
961 if (tty->flow.tco_stopped) {
962 tty->flow.tco_stopped = false;
963 __start_tty(tty);
964 }
965 spin_unlock_irq(&tty->flow.lock);
966 break;
967 case TCIOFF:
968 if (STOP_CHAR(tty) != __DISABLED_CHAR)
969 retval = tty_send_xchar(tty, STOP_CHAR(tty));
970 break;
971 case TCION:
972 if (START_CHAR(tty) != __DISABLED_CHAR)
973 retval = tty_send_xchar(tty, START_CHAR(tty));
974 break;
975 default:
976 return -EINVAL;
977 }
978 return retval;
979 case TCFLSH:
980 retval = tty_check_change(tty);
981 if (retval)
982 return retval;
983 return __tty_perform_flush(tty, arg);
984 default:
985 /* Try the mode commands */
986 return tty_mode_ioctl(tty, cmd, arg);
987 }
988}
989EXPORT_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);