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
tty_chars_in_buffer(struct tty_struct * tty)58 unsigned 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 }
64 EXPORT_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
tty_write_room(struct tty_struct * tty)77 unsigned 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 }
83 EXPORT_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 */
tty_driver_flush_buffer(struct tty_struct * tty)93 void tty_driver_flush_buffer(struct tty_struct *tty)
94 {
95 if (tty->ops->flush_buffer)
96 tty->ops->flush_buffer(tty);
97 }
98 EXPORT_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
tty_unthrottle(struct tty_struct * tty)113 void 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 }
122 EXPORT_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
tty_throttle_safe(struct tty_struct * tty)137 int 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
tty_unthrottle_safe(struct tty_struct * tty)168 int 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
tty_wait_until_sent(struct tty_struct * tty,long timeout)198 void 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 }
216 EXPORT_SYMBOL(tty_wait_until_sent);
217
218
219 /*
220 * Termios Helper Methods
221 */
222
unset_locked_termios(struct tty_struct * tty,const struct ktermios * old)223 static 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
tty_termios_copy_hw(struct ktermios * new,const struct ktermios * old)253 void 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 }
262 EXPORT_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
tty_termios_hw_change(const struct ktermios * a,const struct ktermios * b)273 int 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 }
281 EXPORT_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 */
tty_get_char_size(unsigned int cflag)290 unsigned 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 }
304 EXPORT_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 */
tty_get_frame_size(unsigned int cflag)315 unsigned 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 }
328 EXPORT_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
tty_set_termios(struct tty_struct * tty,struct ktermios * new_termios)341 int 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 }
376 EXPORT_SYMBOL_GPL(tty_set_termios);
377
378
379 /*
380 * Translate a "termio" structure into a "termios". Ugh.
381 */
user_termio_to_kernel_termios(struct ktermios * termios,struct termio __user * termio)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 */
kernel_termios_to_user_termio(struct termio __user * termio,struct ktermios * termios)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
user_termios_to_kernel_termios(struct ktermios * k,struct termios2 __user * u)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 }
kernel_termios_to_user_termios(struct termios2 __user * u,struct ktermios * k)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 }
user_termios_to_kernel_termios_1(struct ktermios * k,struct termios __user * u)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 }
kernel_termios_to_user_termios_1(struct termios __user * u,struct ktermios * k)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
user_termios_to_kernel_termios(struct ktermios * k,struct termios __user * u)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 }
kernel_termios_to_user_termios(struct termios __user * u,struct ktermios * k)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
set_termios(struct tty_struct * tty,void __user * arg,int opt)465 static 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 if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) {
504 retry_write_wait:
505 retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty));
506 if (retval < 0)
507 return retval;
508
509 if (tty_write_lock(tty, false) < 0)
510 goto retry_write_wait;
511
512 /* Racing writer? */
513 if (tty_chars_in_buffer(tty)) {
514 tty_write_unlock(tty);
515 goto retry_write_wait;
516 }
517
518 ld = tty_ldisc_ref(tty);
519 if (ld != NULL) {
520 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
521 ld->ops->flush_buffer(tty);
522 tty_ldisc_deref(ld);
523 }
524
525 if ((opt & TERMIOS_WAIT) && tty->ops->wait_until_sent) {
526 tty->ops->wait_until_sent(tty, 0);
527 if (signal_pending(current)) {
528 tty_write_unlock(tty);
529 return -ERESTARTSYS;
530 }
531 }
532
533 tty_set_termios(tty, &tmp_termios);
534
535 tty_write_unlock(tty);
536 } else {
537 tty_set_termios(tty, &tmp_termios);
538 }
539
540 /* FIXME: Arguably if tmp_termios == tty->termios AND the
541 actual requested termios was not tmp_termios then we may
542 want to return an error as no user requested change has
543 succeeded */
544 return 0;
545 }
546
copy_termios(struct tty_struct * tty,struct ktermios * kterm)547 static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
548 {
549 down_read(&tty->termios_rwsem);
550 *kterm = tty->termios;
551 up_read(&tty->termios_rwsem);
552 }
553
copy_termios_locked(struct tty_struct * tty,struct ktermios * kterm)554 static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
555 {
556 down_read(&tty->termios_rwsem);
557 *kterm = tty->termios_locked;
558 up_read(&tty->termios_rwsem);
559 }
560
get_termio(struct tty_struct * tty,struct termio __user * termio)561 static int get_termio(struct tty_struct *tty, struct termio __user *termio)
562 {
563 struct ktermios kterm;
564 copy_termios(tty, &kterm);
565 if (kernel_termios_to_user_termio(termio, &kterm))
566 return -EFAULT;
567 return 0;
568 }
569
570 #ifdef TIOCGETP
571 /*
572 * These are deprecated, but there is limited support..
573 *
574 * The "sg_flags" translation is a joke..
575 */
get_sgflags(struct tty_struct * tty)576 static int get_sgflags(struct tty_struct *tty)
577 {
578 int flags = 0;
579
580 if (!L_ICANON(tty)) {
581 if (L_ISIG(tty))
582 flags |= 0x02; /* cbreak */
583 else
584 flags |= 0x20; /* raw */
585 }
586 if (L_ECHO(tty))
587 flags |= 0x08; /* echo */
588 if (O_OPOST(tty))
589 if (O_ONLCR(tty))
590 flags |= 0x10; /* crmod */
591 return flags;
592 }
593
get_sgttyb(struct tty_struct * tty,struct sgttyb __user * sgttyb)594 static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
595 {
596 struct sgttyb tmp;
597
598 down_read(&tty->termios_rwsem);
599 tmp.sg_ispeed = tty->termios.c_ispeed;
600 tmp.sg_ospeed = tty->termios.c_ospeed;
601 tmp.sg_erase = tty->termios.c_cc[VERASE];
602 tmp.sg_kill = tty->termios.c_cc[VKILL];
603 tmp.sg_flags = get_sgflags(tty);
604 up_read(&tty->termios_rwsem);
605
606 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
607 }
608
set_sgflags(struct ktermios * termios,int flags)609 static void set_sgflags(struct ktermios *termios, int flags)
610 {
611 termios->c_iflag = ICRNL | IXON;
612 termios->c_oflag = 0;
613 termios->c_lflag = ISIG | ICANON;
614 if (flags & 0x02) { /* cbreak */
615 termios->c_iflag = 0;
616 termios->c_lflag &= ~ICANON;
617 }
618 if (flags & 0x08) { /* echo */
619 termios->c_lflag |= ECHO | ECHOE | ECHOK |
620 ECHOCTL | ECHOKE | IEXTEN;
621 }
622 if (flags & 0x10) { /* crmod */
623 termios->c_oflag |= OPOST | ONLCR;
624 }
625 if (flags & 0x20) { /* raw */
626 termios->c_iflag = 0;
627 termios->c_lflag &= ~(ISIG | ICANON);
628 }
629 if (!(termios->c_lflag & ICANON)) {
630 termios->c_cc[VMIN] = 1;
631 termios->c_cc[VTIME] = 0;
632 }
633 }
634
635 /**
636 * set_sgttyb - set legacy terminal values
637 * @tty: tty structure
638 * @sgttyb: pointer to old style terminal structure
639 *
640 * Updates a terminal from the legacy BSD style terminal information
641 * structure.
642 *
643 * Locking: termios_rwsem
644 */
645
set_sgttyb(struct tty_struct * tty,struct sgttyb __user * sgttyb)646 static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
647 {
648 int retval;
649 struct sgttyb tmp;
650 struct ktermios termios;
651
652 retval = tty_check_change(tty);
653 if (retval)
654 return retval;
655
656 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
657 return -EFAULT;
658
659 down_write(&tty->termios_rwsem);
660 termios = tty->termios;
661 termios.c_cc[VERASE] = tmp.sg_erase;
662 termios.c_cc[VKILL] = tmp.sg_kill;
663 set_sgflags(&termios, tmp.sg_flags);
664 /* Try and encode into Bfoo format */
665 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
666 termios.c_ospeed);
667 up_write(&tty->termios_rwsem);
668 tty_set_termios(tty, &termios);
669 return 0;
670 }
671 #endif
672
673 #ifdef TIOCGETC
get_tchars(struct tty_struct * tty,struct tchars __user * tchars)674 static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
675 {
676 struct tchars tmp;
677
678 down_read(&tty->termios_rwsem);
679 tmp.t_intrc = tty->termios.c_cc[VINTR];
680 tmp.t_quitc = tty->termios.c_cc[VQUIT];
681 tmp.t_startc = tty->termios.c_cc[VSTART];
682 tmp.t_stopc = tty->termios.c_cc[VSTOP];
683 tmp.t_eofc = tty->termios.c_cc[VEOF];
684 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
685 up_read(&tty->termios_rwsem);
686 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
687 }
688
set_tchars(struct tty_struct * tty,struct tchars __user * tchars)689 static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
690 {
691 struct tchars tmp;
692
693 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
694 return -EFAULT;
695 down_write(&tty->termios_rwsem);
696 tty->termios.c_cc[VINTR] = tmp.t_intrc;
697 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
698 tty->termios.c_cc[VSTART] = tmp.t_startc;
699 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
700 tty->termios.c_cc[VEOF] = tmp.t_eofc;
701 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
702 up_write(&tty->termios_rwsem);
703 return 0;
704 }
705 #endif
706
707 #ifdef TIOCGLTC
get_ltchars(struct tty_struct * tty,struct ltchars __user * ltchars)708 static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
709 {
710 struct ltchars tmp;
711
712 down_read(&tty->termios_rwsem);
713 tmp.t_suspc = tty->termios.c_cc[VSUSP];
714 /* what is dsuspc anyway? */
715 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
716 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
717 /* what is flushc anyway? */
718 tmp.t_flushc = tty->termios.c_cc[VEOL2];
719 tmp.t_werasc = tty->termios.c_cc[VWERASE];
720 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
721 up_read(&tty->termios_rwsem);
722 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
723 }
724
set_ltchars(struct tty_struct * tty,struct ltchars __user * ltchars)725 static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
726 {
727 struct ltchars tmp;
728
729 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
730 return -EFAULT;
731
732 down_write(&tty->termios_rwsem);
733 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
734 /* what is dsuspc anyway? */
735 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
736 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
737 /* what is flushc anyway? */
738 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
739 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
740 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
741 up_write(&tty->termios_rwsem);
742 return 0;
743 }
744 #endif
745
746 /**
747 * tty_change_softcar - carrier change ioctl helper
748 * @tty: tty to update
749 * @arg: enable/disable CLOCAL
750 *
751 * Perform a change to the CLOCAL state and call into the driver
752 * layer to make it visible. All done with the termios rwsem
753 */
754
tty_change_softcar(struct tty_struct * tty,int arg)755 static int tty_change_softcar(struct tty_struct *tty, int arg)
756 {
757 int ret = 0;
758 int bit = arg ? CLOCAL : 0;
759 struct ktermios old;
760
761 down_write(&tty->termios_rwsem);
762 old = tty->termios;
763 tty->termios.c_cflag &= ~CLOCAL;
764 tty->termios.c_cflag |= bit;
765 if (tty->ops->set_termios)
766 tty->ops->set_termios(tty, &old);
767 if (C_CLOCAL(tty) != bit)
768 ret = -EINVAL;
769 up_write(&tty->termios_rwsem);
770 return ret;
771 }
772
773 /**
774 * tty_mode_ioctl - mode related ioctls
775 * @tty: tty for the ioctl
776 * @cmd: command
777 * @arg: ioctl argument
778 *
779 * Perform non line discipline specific mode control ioctls. This
780 * is designed to be called by line disciplines to ensure they provide
781 * consistent mode setting.
782 */
783
tty_mode_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)784 int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
785 {
786 struct tty_struct *real_tty;
787 void __user *p = (void __user *)arg;
788 int ret = 0;
789 struct ktermios kterm;
790
791 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
792 tty->driver->subtype == PTY_TYPE_MASTER)
793 real_tty = tty->link;
794 else
795 real_tty = tty;
796
797 switch (cmd) {
798 #ifdef TIOCGETP
799 case TIOCGETP:
800 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
801 case TIOCSETP:
802 case TIOCSETN:
803 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
804 #endif
805 #ifdef TIOCGETC
806 case TIOCGETC:
807 return get_tchars(real_tty, p);
808 case TIOCSETC:
809 return set_tchars(real_tty, p);
810 #endif
811 #ifdef TIOCGLTC
812 case TIOCGLTC:
813 return get_ltchars(real_tty, p);
814 case TIOCSLTC:
815 return set_ltchars(real_tty, p);
816 #endif
817 case TCSETSF:
818 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
819 case TCSETSW:
820 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
821 case TCSETS:
822 return set_termios(real_tty, p, TERMIOS_OLD);
823 #ifndef TCGETS2
824 case TCGETS:
825 copy_termios(real_tty, &kterm);
826 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
827 ret = -EFAULT;
828 return ret;
829 #else
830 case TCGETS:
831 copy_termios(real_tty, &kterm);
832 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
833 ret = -EFAULT;
834 return ret;
835 case TCGETS2:
836 copy_termios(real_tty, &kterm);
837 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
838 ret = -EFAULT;
839 return ret;
840 case TCSETSF2:
841 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
842 case TCSETSW2:
843 return set_termios(real_tty, p, TERMIOS_WAIT);
844 case TCSETS2:
845 return set_termios(real_tty, p, 0);
846 #endif
847 case TCGETA:
848 return get_termio(real_tty, p);
849 case TCSETAF:
850 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
851 case TCSETAW:
852 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
853 case TCSETA:
854 return set_termios(real_tty, p, TERMIOS_TERMIO);
855 #ifndef TCGETS2
856 case TIOCGLCKTRMIOS:
857 copy_termios_locked(real_tty, &kterm);
858 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
859 ret = -EFAULT;
860 return ret;
861 case TIOCSLCKTRMIOS:
862 if (!checkpoint_restore_ns_capable(&init_user_ns))
863 return -EPERM;
864 copy_termios_locked(real_tty, &kterm);
865 if (user_termios_to_kernel_termios(&kterm,
866 (struct termios __user *) arg))
867 return -EFAULT;
868 down_write(&real_tty->termios_rwsem);
869 real_tty->termios_locked = kterm;
870 up_write(&real_tty->termios_rwsem);
871 return 0;
872 #else
873 case TIOCGLCKTRMIOS:
874 copy_termios_locked(real_tty, &kterm);
875 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
876 ret = -EFAULT;
877 return ret;
878 case TIOCSLCKTRMIOS:
879 if (!checkpoint_restore_ns_capable(&init_user_ns))
880 return -EPERM;
881 copy_termios_locked(real_tty, &kterm);
882 if (user_termios_to_kernel_termios_1(&kterm,
883 (struct termios __user *) arg))
884 return -EFAULT;
885 down_write(&real_tty->termios_rwsem);
886 real_tty->termios_locked = kterm;
887 up_write(&real_tty->termios_rwsem);
888 return ret;
889 #endif
890 #ifdef TCGETX
891 case TCGETX:
892 case TCSETX:
893 case TCSETXW:
894 case TCSETXF:
895 return -ENOTTY;
896 #endif
897 case TIOCGSOFTCAR:
898 copy_termios(real_tty, &kterm);
899 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
900 (int __user *)arg);
901 return ret;
902 case TIOCSSOFTCAR:
903 if (get_user(arg, (unsigned int __user *) arg))
904 return -EFAULT;
905 return tty_change_softcar(real_tty, arg);
906 default:
907 return -ENOIOCTLCMD;
908 }
909 }
910 EXPORT_SYMBOL_GPL(tty_mode_ioctl);
911
912
913 /* Caller guarantees ldisc reference is held */
__tty_perform_flush(struct tty_struct * tty,unsigned long arg)914 static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
915 {
916 struct tty_ldisc *ld = tty->ldisc;
917
918 switch (arg) {
919 case TCIFLUSH:
920 if (ld && ld->ops->flush_buffer) {
921 ld->ops->flush_buffer(tty);
922 tty_unthrottle(tty);
923 }
924 break;
925 case TCIOFLUSH:
926 if (ld && ld->ops->flush_buffer) {
927 ld->ops->flush_buffer(tty);
928 tty_unthrottle(tty);
929 }
930 fallthrough;
931 case TCOFLUSH:
932 tty_driver_flush_buffer(tty);
933 break;
934 default:
935 return -EINVAL;
936 }
937 return 0;
938 }
939
tty_perform_flush(struct tty_struct * tty,unsigned long arg)940 int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
941 {
942 struct tty_ldisc *ld;
943 int retval = tty_check_change(tty);
944 if (retval)
945 return retval;
946
947 ld = tty_ldisc_ref_wait(tty);
948 retval = __tty_perform_flush(tty, arg);
949 if (ld)
950 tty_ldisc_deref(ld);
951 return retval;
952 }
953 EXPORT_SYMBOL_GPL(tty_perform_flush);
954
n_tty_ioctl_helper(struct tty_struct * tty,unsigned int cmd,unsigned long arg)955 int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd,
956 unsigned long arg)
957 {
958 int retval;
959
960 switch (cmd) {
961 case TCXONC:
962 retval = tty_check_change(tty);
963 if (retval)
964 return retval;
965 switch (arg) {
966 case TCOOFF:
967 spin_lock_irq(&tty->flow.lock);
968 if (!tty->flow.tco_stopped) {
969 tty->flow.tco_stopped = true;
970 __stop_tty(tty);
971 }
972 spin_unlock_irq(&tty->flow.lock);
973 break;
974 case TCOON:
975 spin_lock_irq(&tty->flow.lock);
976 if (tty->flow.tco_stopped) {
977 tty->flow.tco_stopped = false;
978 __start_tty(tty);
979 }
980 spin_unlock_irq(&tty->flow.lock);
981 break;
982 case TCIOFF:
983 if (STOP_CHAR(tty) != __DISABLED_CHAR)
984 retval = tty_send_xchar(tty, STOP_CHAR(tty));
985 break;
986 case TCION:
987 if (START_CHAR(tty) != __DISABLED_CHAR)
988 retval = tty_send_xchar(tty, START_CHAR(tty));
989 break;
990 default:
991 return -EINVAL;
992 }
993 return retval;
994 case TCFLSH:
995 retval = tty_check_change(tty);
996 if (retval)
997 return retval;
998 return __tty_perform_flush(tty, arg);
999 default:
1000 /* Try the mode commands */
1001 return tty_mode_ioctl(tty, cmd, arg);
1002 }
1003 }
1004 EXPORT_SYMBOL(n_tty_ioctl_helper);
1005