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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 <linux/termios_internal.h>
25#include "tty.h"
26
27#include <asm/io.h>
28#include <linux/uaccess.h>
29
30#undef TTY_DEBUG_WAIT_UNTIL_SENT
31
32#ifdef TTY_DEBUG_WAIT_UNTIL_SENT
33# define tty_debug_wait_until_sent(tty, f, args...) tty_debug(tty, f, ##args)
34#else
35# define tty_debug_wait_until_sent(tty, f, args...) do {} while (0)
36#endif
37
38#undef DEBUG
39
40/*
41 * Internal flag options for termios setting behavior
42 */
43#define TERMIOS_FLUSH 1
44#define TERMIOS_WAIT 2
45#define TERMIOS_TERMIO 4
46#define TERMIOS_OLD 8
47
48
49/**
50 * tty_chars_in_buffer - characters pending
51 * @tty: terminal
52 *
53 * Return the number of bytes of data in the device private
54 * output queue. If no private method is supplied there is assumed
55 * to be no queue on the device.
56 */
57
58unsigned int tty_chars_in_buffer(struct tty_struct *tty)
59{
60 if (tty->ops->chars_in_buffer)
61 return tty->ops->chars_in_buffer(tty);
62 return 0;
63}
64EXPORT_SYMBOL(tty_chars_in_buffer);
65
66/**
67 * tty_write_room - write queue space
68 * @tty: terminal
69 *
70 * Return the number of bytes that can be queued to this device
71 * at the present time. The result should be treated as a guarantee
72 * and the driver cannot offer a value it later shrinks by more than
73 * the number of bytes written. If no method is provided 2K is always
74 * returned and data may be lost as there will be no flow control.
75 */
76
77unsigned int tty_write_room(struct tty_struct *tty)
78{
79 if (tty->ops->write_room)
80 return tty->ops->write_room(tty);
81 return 2048;
82}
83EXPORT_SYMBOL(tty_write_room);
84
85/**
86 * tty_driver_flush_buffer - discard internal buffer
87 * @tty: terminal
88 *
89 * Discard the internal output buffer for this device. If no method
90 * is provided then either the buffer cannot be hardware flushed or
91 * there is no buffer driver side.
92 */
93void tty_driver_flush_buffer(struct tty_struct *tty)
94{
95 if (tty->ops->flush_buffer)
96 tty->ops->flush_buffer(tty);
97}
98EXPORT_SYMBOL(tty_driver_flush_buffer);
99
100/**
101 * tty_unthrottle - flow control
102 * @tty: terminal
103 *
104 * Indicate that a tty may continue transmitting data down the stack.
105 * Takes the termios rwsem to protect against parallel throttle/unthrottle
106 * and also to ensure the driver can consistently reference its own
107 * termios data at this point when implementing software flow control.
108 *
109 * Drivers should however remember that the stack can issue a throttle,
110 * then change flow control method, then unthrottle.
111 */
112
113void tty_unthrottle(struct tty_struct *tty)
114{
115 down_write(&tty->termios_rwsem);
116 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
117 tty->ops->unthrottle)
118 tty->ops->unthrottle(tty);
119 tty->flow_change = 0;
120 up_write(&tty->termios_rwsem);
121}
122EXPORT_SYMBOL(tty_unthrottle);
123
124/**
125 * tty_throttle_safe - flow control
126 * @tty: terminal
127 *
128 * Indicate that a tty should stop transmitting data down the stack.
129 * tty_throttle_safe will only attempt throttle if tty->flow_change is
130 * TTY_THROTTLE_SAFE. Prevents an accidental throttle due to race
131 * conditions when throttling is conditional on factors evaluated prior to
132 * throttling.
133 *
134 * Returns 0 if tty is throttled (or was already throttled)
135 */
136
137int tty_throttle_safe(struct tty_struct *tty)
138{
139 int ret = 0;
140
141 mutex_lock(&tty->throttle_mutex);
142 if (!tty_throttled(tty)) {
143 if (tty->flow_change != TTY_THROTTLE_SAFE)
144 ret = 1;
145 else {
146 set_bit(TTY_THROTTLED, &tty->flags);
147 if (tty->ops->throttle)
148 tty->ops->throttle(tty);
149 }
150 }
151 mutex_unlock(&tty->throttle_mutex);
152
153 return ret;
154}
155
156/**
157 * tty_unthrottle_safe - flow control
158 * @tty: terminal
159 *
160 * Similar to tty_unthrottle() but will only attempt unthrottle
161 * if tty->flow_change is TTY_UNTHROTTLE_SAFE. Prevents an accidental
162 * unthrottle due to race conditions when unthrottling is conditional
163 * on factors evaluated prior to unthrottling.
164 *
165 * Returns 0 if tty is unthrottled (or was already unthrottled)
166 */
167
168int tty_unthrottle_safe(struct tty_struct *tty)
169{
170 int ret = 0;
171
172 mutex_lock(&tty->throttle_mutex);
173 if (tty_throttled(tty)) {
174 if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
175 ret = 1;
176 else {
177 clear_bit(TTY_THROTTLED, &tty->flags);
178 if (tty->ops->unthrottle)
179 tty->ops->unthrottle(tty);
180 }
181 }
182 mutex_unlock(&tty->throttle_mutex);
183
184 return ret;
185}
186
187/**
188 * tty_wait_until_sent - wait for I/O to finish
189 * @tty: tty we are waiting for
190 * @timeout: how long we will wait
191 *
192 * Wait for characters pending in a tty driver to hit the wire, or
193 * for a timeout to occur (eg due to flow control)
194 *
195 * Locking: none
196 */
197
198void tty_wait_until_sent(struct tty_struct *tty, long timeout)
199{
200 tty_debug_wait_until_sent(tty, "wait until sent, timeout=%ld\n", timeout);
201
202 if (!timeout)
203 timeout = MAX_SCHEDULE_TIMEOUT;
204
205 timeout = wait_event_interruptible_timeout(tty->write_wait,
206 !tty_chars_in_buffer(tty), timeout);
207 if (timeout <= 0)
208 return;
209
210 if (timeout == MAX_SCHEDULE_TIMEOUT)
211 timeout = 0;
212
213 if (tty->ops->wait_until_sent)
214 tty->ops->wait_until_sent(tty, timeout);
215}
216EXPORT_SYMBOL(tty_wait_until_sent);
217
218
219/*
220 * Termios Helper Methods
221 */
222
223static void unset_locked_termios(struct tty_struct *tty, const struct ktermios *old)
224{
225 struct ktermios *termios = &tty->termios;
226 struct ktermios *locked = &tty->termios_locked;
227 int i;
228
229#define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
230
231 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
232 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
233 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
234 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
235 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
236 for (i = 0; i < NCCS; i++)
237 termios->c_cc[i] = locked->c_cc[i] ?
238 old->c_cc[i] : termios->c_cc[i];
239 /* FIXME: What should we do for i/ospeed */
240}
241
242/**
243 * tty_termios_copy_hw - copy hardware settings
244 * @new: New termios
245 * @old: Old termios
246 *
247 * Propagate the hardware specific terminal setting bits from
248 * the old termios structure to the new one. This is used in cases
249 * where the hardware does not support reconfiguration or as a helper
250 * in some cases where only minimal reconfiguration is supported
251 */
252
253void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old)
254{
255 /* The bits a dumb device handles in software. Smart devices need
256 to always provide a set_termios method */
257 new->c_cflag &= HUPCL | CREAD | CLOCAL;
258 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
259 new->c_ispeed = old->c_ispeed;
260 new->c_ospeed = old->c_ospeed;
261}
262EXPORT_SYMBOL(tty_termios_copy_hw);
263
264/**
265 * tty_termios_hw_change - check for setting change
266 * @a: termios
267 * @b: termios to compare
268 *
269 * Check if any of the bits that affect a dumb device have changed
270 * between the two termios structures, or a speed change is needed.
271 */
272
273int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
274{
275 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
276 return 1;
277 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
278 return 1;
279 return 0;
280}
281EXPORT_SYMBOL(tty_termios_hw_change);
282
283/**
284 * tty_get_char_size - get size of a character
285 * @cflag: termios cflag value
286 *
287 * Get the size (in bits) of a character depending on @cflag's %CSIZE
288 * setting.
289 */
290unsigned char tty_get_char_size(unsigned int cflag)
291{
292 switch (cflag & CSIZE) {
293 case CS5:
294 return 5;
295 case CS6:
296 return 6;
297 case CS7:
298 return 7;
299 case CS8:
300 default:
301 return 8;
302 }
303}
304EXPORT_SYMBOL_GPL(tty_get_char_size);
305
306/**
307 * tty_get_frame_size - get size of a frame
308 * @cflag: termios cflag value
309 *
310 * Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB,
311 * and %PARENB setting. The result is a sum of character size, start and
312 * stop bits -- one bit each -- second stop bit (if set), and parity bit
313 * (if set).
314 */
315unsigned char tty_get_frame_size(unsigned int cflag)
316{
317 unsigned char bits = 2 + tty_get_char_size(cflag);
318
319 if (cflag & CSTOPB)
320 bits++;
321 if (cflag & PARENB)
322 bits++;
323 if (cflag & ADDRB)
324 bits++;
325
326 return bits;
327}
328EXPORT_SYMBOL_GPL(tty_get_frame_size);
329
330/**
331 * tty_set_termios - update termios values
332 * @tty: tty to update
333 * @new_termios: desired new value
334 *
335 * Perform updates to the termios values set on this terminal.
336 * A master pty's termios should never be set.
337 *
338 * Locking: termios_rwsem
339 */
340
341int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
342{
343 struct ktermios old_termios;
344 struct tty_ldisc *ld;
345
346 WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
347 tty->driver->subtype == PTY_TYPE_MASTER);
348 /*
349 * Perform the actual termios internal changes under lock.
350 */
351
352
353 /* FIXME: we need to decide on some locking/ordering semantics
354 for the set_termios notification eventually */
355 down_write(&tty->termios_rwsem);
356 old_termios = tty->termios;
357 tty->termios = *new_termios;
358 unset_locked_termios(tty, &old_termios);
359 /* Reset any ADDRB changes, ADDRB is changed through ->rs485_config() */
360 tty->termios.c_cflag ^= (tty->termios.c_cflag ^ old_termios.c_cflag) & ADDRB;
361
362 if (tty->ops->set_termios)
363 tty->ops->set_termios(tty, &old_termios);
364 else
365 tty_termios_copy_hw(&tty->termios, &old_termios);
366
367 ld = tty_ldisc_ref(tty);
368 if (ld != NULL) {
369 if (ld->ops->set_termios)
370 ld->ops->set_termios(tty, &old_termios);
371 tty_ldisc_deref(ld);
372 }
373 up_write(&tty->termios_rwsem);
374 return 0;
375}
376EXPORT_SYMBOL_GPL(tty_set_termios);
377
378
379/*
380 * Translate a "termio" structure into a "termios". Ugh.
381 */
382__weak int user_termio_to_kernel_termios(struct ktermios *termios,
383 struct termio __user *termio)
384{
385 struct termio v;
386
387 if (copy_from_user(&v, termio, sizeof(struct termio)))
388 return -EFAULT;
389
390 termios->c_iflag = (0xffff0000 & termios->c_iflag) | v.c_iflag;
391 termios->c_oflag = (0xffff0000 & termios->c_oflag) | v.c_oflag;
392 termios->c_cflag = (0xffff0000 & termios->c_cflag) | v.c_cflag;
393 termios->c_lflag = (0xffff0000 & termios->c_lflag) | v.c_lflag;
394 termios->c_line = (0xffff0000 & termios->c_lflag) | v.c_line;
395 memcpy(termios->c_cc, v.c_cc, NCC);
396 return 0;
397}
398
399/*
400 * Translate a "termios" structure into a "termio". Ugh.
401 */
402__weak int kernel_termios_to_user_termio(struct termio __user *termio,
403 struct ktermios *termios)
404{
405 struct termio v;
406 memset(&v, 0, sizeof(struct termio));
407 v.c_iflag = termios->c_iflag;
408 v.c_oflag = termios->c_oflag;
409 v.c_cflag = termios->c_cflag;
410 v.c_lflag = termios->c_lflag;
411 v.c_line = termios->c_line;
412 memcpy(v.c_cc, termios->c_cc, NCC);
413 return copy_to_user(termio, &v, sizeof(struct termio));
414}
415
416#ifdef TCGETS2
417__weak int user_termios_to_kernel_termios(struct ktermios *k,
418 struct termios2 __user *u)
419{
420 return copy_from_user(k, u, sizeof(struct termios2));
421}
422__weak int kernel_termios_to_user_termios(struct termios2 __user *u,
423 struct ktermios *k)
424{
425 return copy_to_user(u, k, sizeof(struct termios2));
426}
427__weak int user_termios_to_kernel_termios_1(struct ktermios *k,
428 struct termios __user *u)
429{
430 return copy_from_user(k, u, sizeof(struct termios));
431}
432__weak int kernel_termios_to_user_termios_1(struct termios __user *u,
433 struct ktermios *k)
434{
435 return copy_to_user(u, k, sizeof(struct termios));
436}
437
438#else
439
440__weak int user_termios_to_kernel_termios(struct ktermios *k,
441 struct termios __user *u)
442{
443 return copy_from_user(k, u, sizeof(struct termios));
444}
445__weak int kernel_termios_to_user_termios(struct termios __user *u,
446 struct ktermios *k)
447{
448 return copy_to_user(u, k, sizeof(struct termios));
449}
450#endif /* TCGETS2 */
451
452/**
453 * set_termios - set termios values for a tty
454 * @tty: terminal device
455 * @arg: user data
456 * @opt: option information
457 *
458 * Helper function to prepare termios data and run necessary other
459 * functions before using tty_set_termios to do the actual changes.
460 *
461 * Locking:
462 * Called functions take ldisc and termios_rwsem locks
463 */
464
465static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
466{
467 struct ktermios tmp_termios;
468 struct tty_ldisc *ld;
469 int retval = tty_check_change(tty);
470
471 if (retval)
472 return retval;
473
474 down_read(&tty->termios_rwsem);
475 tmp_termios = tty->termios;
476 up_read(&tty->termios_rwsem);
477
478 if (opt & TERMIOS_TERMIO) {
479 if (user_termio_to_kernel_termios(&tmp_termios,
480 (struct termio __user *)arg))
481 return -EFAULT;
482#ifdef TCGETS2
483 } else if (opt & TERMIOS_OLD) {
484 if (user_termios_to_kernel_termios_1(&tmp_termios,
485 (struct termios __user *)arg))
486 return -EFAULT;
487 } else {
488 if (user_termios_to_kernel_termios(&tmp_termios,
489 (struct termios2 __user *)arg))
490 return -EFAULT;
491 }
492#else
493 } else if (user_termios_to_kernel_termios(&tmp_termios,
494 (struct termios __user *)arg))
495 return -EFAULT;
496#endif
497
498 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
499 * with the real speed so its unconditionally usable */
500 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
501 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
502
503 ld = tty_ldisc_ref(tty);
504
505 if (ld != NULL) {
506 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
507 ld->ops->flush_buffer(tty);
508 tty_ldisc_deref(ld);
509 }
510
511 if (opt & TERMIOS_WAIT) {
512 tty_wait_until_sent(tty, 0);
513 if (signal_pending(current))
514 return -ERESTARTSYS;
515 }
516
517 tty_set_termios(tty, &tmp_termios);
518
519 /* FIXME: Arguably if tmp_termios == tty->termios AND the
520 actual requested termios was not tmp_termios then we may
521 want to return an error as no user requested change has
522 succeeded */
523 return 0;
524}
525
526static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
527{
528 down_read(&tty->termios_rwsem);
529 *kterm = tty->termios;
530 up_read(&tty->termios_rwsem);
531}
532
533static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
534{
535 down_read(&tty->termios_rwsem);
536 *kterm = tty->termios_locked;
537 up_read(&tty->termios_rwsem);
538}
539
540static int get_termio(struct tty_struct *tty, struct termio __user *termio)
541{
542 struct ktermios kterm;
543 copy_termios(tty, &kterm);
544 if (kernel_termios_to_user_termio(termio, &kterm))
545 return -EFAULT;
546 return 0;
547}
548
549#ifdef TIOCGETP
550/*
551 * These are deprecated, but there is limited support..
552 *
553 * The "sg_flags" translation is a joke..
554 */
555static int get_sgflags(struct tty_struct *tty)
556{
557 int flags = 0;
558
559 if (!L_ICANON(tty)) {
560 if (L_ISIG(tty))
561 flags |= 0x02; /* cbreak */
562 else
563 flags |= 0x20; /* raw */
564 }
565 if (L_ECHO(tty))
566 flags |= 0x08; /* echo */
567 if (O_OPOST(tty))
568 if (O_ONLCR(tty))
569 flags |= 0x10; /* crmod */
570 return flags;
571}
572
573static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
574{
575 struct sgttyb tmp;
576
577 down_read(&tty->termios_rwsem);
578 tmp.sg_ispeed = tty->termios.c_ispeed;
579 tmp.sg_ospeed = tty->termios.c_ospeed;
580 tmp.sg_erase = tty->termios.c_cc[VERASE];
581 tmp.sg_kill = tty->termios.c_cc[VKILL];
582 tmp.sg_flags = get_sgflags(tty);
583 up_read(&tty->termios_rwsem);
584
585 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
586}
587
588static void set_sgflags(struct ktermios *termios, int flags)
589{
590 termios->c_iflag = ICRNL | IXON;
591 termios->c_oflag = 0;
592 termios->c_lflag = ISIG | ICANON;
593 if (flags & 0x02) { /* cbreak */
594 termios->c_iflag = 0;
595 termios->c_lflag &= ~ICANON;
596 }
597 if (flags & 0x08) { /* echo */
598 termios->c_lflag |= ECHO | ECHOE | ECHOK |
599 ECHOCTL | ECHOKE | IEXTEN;
600 }
601 if (flags & 0x10) { /* crmod */
602 termios->c_oflag |= OPOST | ONLCR;
603 }
604 if (flags & 0x20) { /* raw */
605 termios->c_iflag = 0;
606 termios->c_lflag &= ~(ISIG | ICANON);
607 }
608 if (!(termios->c_lflag & ICANON)) {
609 termios->c_cc[VMIN] = 1;
610 termios->c_cc[VTIME] = 0;
611 }
612}
613
614/**
615 * set_sgttyb - set legacy terminal values
616 * @tty: tty structure
617 * @sgttyb: pointer to old style terminal structure
618 *
619 * Updates a terminal from the legacy BSD style terminal information
620 * structure.
621 *
622 * Locking: termios_rwsem
623 */
624
625static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
626{
627 int retval;
628 struct sgttyb tmp;
629 struct ktermios termios;
630
631 retval = tty_check_change(tty);
632 if (retval)
633 return retval;
634
635 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
636 return -EFAULT;
637
638 down_write(&tty->termios_rwsem);
639 termios = tty->termios;
640 termios.c_cc[VERASE] = tmp.sg_erase;
641 termios.c_cc[VKILL] = tmp.sg_kill;
642 set_sgflags(&termios, tmp.sg_flags);
643 /* Try and encode into Bfoo format */
644 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
645 termios.c_ospeed);
646 up_write(&tty->termios_rwsem);
647 tty_set_termios(tty, &termios);
648 return 0;
649}
650#endif
651
652#ifdef TIOCGETC
653static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
654{
655 struct tchars tmp;
656
657 down_read(&tty->termios_rwsem);
658 tmp.t_intrc = tty->termios.c_cc[VINTR];
659 tmp.t_quitc = tty->termios.c_cc[VQUIT];
660 tmp.t_startc = tty->termios.c_cc[VSTART];
661 tmp.t_stopc = tty->termios.c_cc[VSTOP];
662 tmp.t_eofc = tty->termios.c_cc[VEOF];
663 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
664 up_read(&tty->termios_rwsem);
665 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
666}
667
668static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
669{
670 struct tchars tmp;
671
672 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
673 return -EFAULT;
674 down_write(&tty->termios_rwsem);
675 tty->termios.c_cc[VINTR] = tmp.t_intrc;
676 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
677 tty->termios.c_cc[VSTART] = tmp.t_startc;
678 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
679 tty->termios.c_cc[VEOF] = tmp.t_eofc;
680 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
681 up_write(&tty->termios_rwsem);
682 return 0;
683}
684#endif
685
686#ifdef TIOCGLTC
687static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
688{
689 struct ltchars tmp;
690
691 down_read(&tty->termios_rwsem);
692 tmp.t_suspc = tty->termios.c_cc[VSUSP];
693 /* what is dsuspc anyway? */
694 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
695 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
696 /* what is flushc anyway? */
697 tmp.t_flushc = tty->termios.c_cc[VEOL2];
698 tmp.t_werasc = tty->termios.c_cc[VWERASE];
699 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
700 up_read(&tty->termios_rwsem);
701 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
702}
703
704static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
705{
706 struct ltchars tmp;
707
708 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
709 return -EFAULT;
710
711 down_write(&tty->termios_rwsem);
712 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
713 /* what is dsuspc anyway? */
714 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
715 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
716 /* what is flushc anyway? */
717 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
718 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
719 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
720 up_write(&tty->termios_rwsem);
721 return 0;
722}
723#endif
724
725/**
726 * tty_change_softcar - carrier change ioctl helper
727 * @tty: tty to update
728 * @arg: enable/disable CLOCAL
729 *
730 * Perform a change to the CLOCAL state and call into the driver
731 * layer to make it visible. All done with the termios rwsem
732 */
733
734static int tty_change_softcar(struct tty_struct *tty, int arg)
735{
736 int ret = 0;
737 int bit = arg ? CLOCAL : 0;
738 struct ktermios old;
739
740 down_write(&tty->termios_rwsem);
741 old = tty->termios;
742 tty->termios.c_cflag &= ~CLOCAL;
743 tty->termios.c_cflag |= bit;
744 if (tty->ops->set_termios)
745 tty->ops->set_termios(tty, &old);
746 if (C_CLOCAL(tty) != bit)
747 ret = -EINVAL;
748 up_write(&tty->termios_rwsem);
749 return ret;
750}
751
752/**
753 * tty_mode_ioctl - mode related ioctls
754 * @tty: tty for the ioctl
755 * @cmd: command
756 * @arg: ioctl argument
757 *
758 * Perform non line discipline specific mode control ioctls. This
759 * is designed to be called by line disciplines to ensure they provide
760 * consistent mode setting.
761 */
762
763int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
764{
765 struct tty_struct *real_tty;
766 void __user *p = (void __user *)arg;
767 int ret = 0;
768 struct ktermios kterm;
769
770 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
771 tty->driver->subtype == PTY_TYPE_MASTER)
772 real_tty = tty->link;
773 else
774 real_tty = tty;
775
776 switch (cmd) {
777#ifdef TIOCGETP
778 case TIOCGETP:
779 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
780 case TIOCSETP:
781 case TIOCSETN:
782 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
783#endif
784#ifdef TIOCGETC
785 case TIOCGETC:
786 return get_tchars(real_tty, p);
787 case TIOCSETC:
788 return set_tchars(real_tty, p);
789#endif
790#ifdef TIOCGLTC
791 case TIOCGLTC:
792 return get_ltchars(real_tty, p);
793 case TIOCSLTC:
794 return set_ltchars(real_tty, p);
795#endif
796 case TCSETSF:
797 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
798 case TCSETSW:
799 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
800 case TCSETS:
801 return set_termios(real_tty, p, TERMIOS_OLD);
802#ifndef TCGETS2
803 case TCGETS:
804 copy_termios(real_tty, &kterm);
805 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
806 ret = -EFAULT;
807 return ret;
808#else
809 case TCGETS:
810 copy_termios(real_tty, &kterm);
811 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
812 ret = -EFAULT;
813 return ret;
814 case TCGETS2:
815 copy_termios(real_tty, &kterm);
816 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
817 ret = -EFAULT;
818 return ret;
819 case TCSETSF2:
820 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
821 case TCSETSW2:
822 return set_termios(real_tty, p, TERMIOS_WAIT);
823 case TCSETS2:
824 return set_termios(real_tty, p, 0);
825#endif
826 case TCGETA:
827 return get_termio(real_tty, p);
828 case TCSETAF:
829 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
830 case TCSETAW:
831 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
832 case TCSETA:
833 return set_termios(real_tty, p, TERMIOS_TERMIO);
834#ifndef TCGETS2
835 case TIOCGLCKTRMIOS:
836 copy_termios_locked(real_tty, &kterm);
837 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
838 ret = -EFAULT;
839 return ret;
840 case TIOCSLCKTRMIOS:
841 if (!capable(CAP_SYS_ADMIN))
842 return -EPERM;
843 copy_termios_locked(real_tty, &kterm);
844 if (user_termios_to_kernel_termios(&kterm,
845 (struct termios __user *) arg))
846 return -EFAULT;
847 down_write(&real_tty->termios_rwsem);
848 real_tty->termios_locked = kterm;
849 up_write(&real_tty->termios_rwsem);
850 return 0;
851#else
852 case TIOCGLCKTRMIOS:
853 copy_termios_locked(real_tty, &kterm);
854 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
855 ret = -EFAULT;
856 return ret;
857 case TIOCSLCKTRMIOS:
858 if (!capable(CAP_SYS_ADMIN))
859 return -EPERM;
860 copy_termios_locked(real_tty, &kterm);
861 if (user_termios_to_kernel_termios_1(&kterm,
862 (struct termios __user *) arg))
863 return -EFAULT;
864 down_write(&real_tty->termios_rwsem);
865 real_tty->termios_locked = kterm;
866 up_write(&real_tty->termios_rwsem);
867 return ret;
868#endif
869#ifdef TCGETX
870 case TCGETX:
871 case TCSETX:
872 case TCSETXW:
873 case TCSETXF:
874 return -ENOTTY;
875#endif
876 case TIOCGSOFTCAR:
877 copy_termios(real_tty, &kterm);
878 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
879 (int __user *)arg);
880 return ret;
881 case TIOCSSOFTCAR:
882 if (get_user(arg, (unsigned int __user *) arg))
883 return -EFAULT;
884 return tty_change_softcar(real_tty, arg);
885 default:
886 return -ENOIOCTLCMD;
887 }
888}
889EXPORT_SYMBOL_GPL(tty_mode_ioctl);
890
891
892/* Caller guarantees ldisc reference is held */
893static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
894{
895 struct tty_ldisc *ld = tty->ldisc;
896
897 switch (arg) {
898 case TCIFLUSH:
899 if (ld && ld->ops->flush_buffer) {
900 ld->ops->flush_buffer(tty);
901 tty_unthrottle(tty);
902 }
903 break;
904 case TCIOFLUSH:
905 if (ld && ld->ops->flush_buffer) {
906 ld->ops->flush_buffer(tty);
907 tty_unthrottle(tty);
908 }
909 fallthrough;
910 case TCOFLUSH:
911 tty_driver_flush_buffer(tty);
912 break;
913 default:
914 return -EINVAL;
915 }
916 return 0;
917}
918
919int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
920{
921 struct tty_ldisc *ld;
922 int retval = tty_check_change(tty);
923 if (retval)
924 return retval;
925
926 ld = tty_ldisc_ref_wait(tty);
927 retval = __tty_perform_flush(tty, arg);
928 if (ld)
929 tty_ldisc_deref(ld);
930 return retval;
931}
932EXPORT_SYMBOL_GPL(tty_perform_flush);
933
934int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
935 unsigned long arg)
936{
937 int retval;
938
939 switch (cmd) {
940 case TCXONC:
941 retval = tty_check_change(tty);
942 if (retval)
943 return retval;
944 switch (arg) {
945 case TCOOFF:
946 spin_lock_irq(&tty->flow.lock);
947 if (!tty->flow.tco_stopped) {
948 tty->flow.tco_stopped = true;
949 __stop_tty(tty);
950 }
951 spin_unlock_irq(&tty->flow.lock);
952 break;
953 case TCOON:
954 spin_lock_irq(&tty->flow.lock);
955 if (tty->flow.tco_stopped) {
956 tty->flow.tco_stopped = false;
957 __start_tty(tty);
958 }
959 spin_unlock_irq(&tty->flow.lock);
960 break;
961 case TCIOFF:
962 if (STOP_CHAR(tty) != __DISABLED_CHAR)
963 retval = tty_send_xchar(tty, STOP_CHAR(tty));
964 break;
965 case TCION:
966 if (START_CHAR(tty) != __DISABLED_CHAR)
967 retval = tty_send_xchar(tty, START_CHAR(tty));
968 break;
969 default:
970 return -EINVAL;
971 }
972 return retval;
973 case TCFLSH:
974 retval = tty_check_change(tty);
975 if (retval)
976 return retval;
977 return __tty_perform_flush(tty, arg);
978 default:
979 /* Try the mode commands */
980 return tty_mode_ioctl(tty, cmd, arg);
981 }
982}
983EXPORT_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);