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
25 #include <asm/io.h>
26 #include <linux/uaccess.h>
27
28 #undef TTY_DEBUG_WAIT_UNTIL_SENT
29
30 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
31 # define tty_debug_wait_until_sent(tty, f, args...) tty_debug(tty, f, ##args)
32 #else
33 # define tty_debug_wait_until_sent(tty, f, args...) do {} while (0)
34 #endif
35
36 #undef DEBUG
37
38 /*
39 * Internal flag options for termios setting behavior
40 */
41 #define TERMIOS_FLUSH 1
42 #define TERMIOS_WAIT 2
43 #define TERMIOS_TERMIO 4
44 #define TERMIOS_OLD 8
45
46
47 /**
48 * tty_chars_in_buffer - characters pending
49 * @tty: terminal
50 *
51 * Return the number of bytes of data in the device private
52 * output queue. If no private method is supplied there is assumed
53 * to be no queue on the device.
54 */
55
tty_chars_in_buffer(struct tty_struct * tty)56 int tty_chars_in_buffer(struct tty_struct *tty)
57 {
58 if (tty->ops->chars_in_buffer)
59 return tty->ops->chars_in_buffer(tty);
60 else
61 return 0;
62 }
63 EXPORT_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
tty_write_room(struct tty_struct * tty)76 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 }
82 EXPORT_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 */
tty_driver_flush_buffer(struct tty_struct * tty)92 void tty_driver_flush_buffer(struct tty_struct *tty)
93 {
94 if (tty->ops->flush_buffer)
95 tty->ops->flush_buffer(tty);
96 }
97 EXPORT_SYMBOL(tty_driver_flush_buffer);
98
99 /**
100 * tty_throttle - flow control
101 * @tty: terminal
102 *
103 * Indicate that a tty should stop 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
tty_throttle(struct tty_struct * tty)109 void tty_throttle(struct tty_struct *tty)
110 {
111 down_write(&tty->termios_rwsem);
112 /* check TTY_THROTTLED first so it indicates our state */
113 if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
114 tty->ops->throttle)
115 tty->ops->throttle(tty);
116 tty->flow_change = 0;
117 up_write(&tty->termios_rwsem);
118 }
119 EXPORT_SYMBOL(tty_throttle);
120
121 /**
122 * tty_unthrottle - flow control
123 * @tty: terminal
124 *
125 * Indicate that a tty may continue transmitting data down the stack.
126 * Takes the termios rwsem to protect against parallel throttle/unthrottle
127 * and also to ensure the driver can consistently reference its own
128 * termios data at this point when implementing software flow control.
129 *
130 * Drivers should however remember that the stack can issue a throttle,
131 * then change flow control method, then unthrottle.
132 */
133
tty_unthrottle(struct tty_struct * tty)134 void tty_unthrottle(struct tty_struct *tty)
135 {
136 down_write(&tty->termios_rwsem);
137 if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
138 tty->ops->unthrottle)
139 tty->ops->unthrottle(tty);
140 tty->flow_change = 0;
141 up_write(&tty->termios_rwsem);
142 }
143 EXPORT_SYMBOL(tty_unthrottle);
144
145 /**
146 * tty_throttle_safe - flow control
147 * @tty: terminal
148 *
149 * Similar to tty_throttle() but will only attempt throttle
150 * if tty->flow_change is TTY_THROTTLE_SAFE. Prevents an accidental
151 * throttle due to race conditions when throttling is conditional
152 * on factors evaluated prior to throttling.
153 *
154 * Returns 0 if tty is throttled (or was already throttled)
155 */
156
tty_throttle_safe(struct tty_struct * tty)157 int tty_throttle_safe(struct tty_struct *tty)
158 {
159 int ret = 0;
160
161 mutex_lock(&tty->throttle_mutex);
162 if (!tty_throttled(tty)) {
163 if (tty->flow_change != TTY_THROTTLE_SAFE)
164 ret = 1;
165 else {
166 set_bit(TTY_THROTTLED, &tty->flags);
167 if (tty->ops->throttle)
168 tty->ops->throttle(tty);
169 }
170 }
171 mutex_unlock(&tty->throttle_mutex);
172
173 return ret;
174 }
175
176 /**
177 * tty_unthrottle_safe - flow control
178 * @tty: terminal
179 *
180 * Similar to tty_unthrottle() but will only attempt unthrottle
181 * if tty->flow_change is TTY_UNTHROTTLE_SAFE. Prevents an accidental
182 * unthrottle due to race conditions when unthrottling is conditional
183 * on factors evaluated prior to unthrottling.
184 *
185 * Returns 0 if tty is unthrottled (or was already unthrottled)
186 */
187
tty_unthrottle_safe(struct tty_struct * tty)188 int tty_unthrottle_safe(struct tty_struct *tty)
189 {
190 int ret = 0;
191
192 mutex_lock(&tty->throttle_mutex);
193 if (tty_throttled(tty)) {
194 if (tty->flow_change != TTY_UNTHROTTLE_SAFE)
195 ret = 1;
196 else {
197 clear_bit(TTY_THROTTLED, &tty->flags);
198 if (tty->ops->unthrottle)
199 tty->ops->unthrottle(tty);
200 }
201 }
202 mutex_unlock(&tty->throttle_mutex);
203
204 return ret;
205 }
206
207 /**
208 * tty_wait_until_sent - wait for I/O to finish
209 * @tty: tty we are waiting for
210 * @timeout: how long we will wait
211 *
212 * Wait for characters pending in a tty driver to hit the wire, or
213 * for a timeout to occur (eg due to flow control)
214 *
215 * Locking: none
216 */
217
tty_wait_until_sent(struct tty_struct * tty,long timeout)218 void tty_wait_until_sent(struct tty_struct *tty, long timeout)
219 {
220 tty_debug_wait_until_sent(tty, "wait until sent, timeout=%ld\n", timeout);
221
222 if (!timeout)
223 timeout = MAX_SCHEDULE_TIMEOUT;
224
225 timeout = wait_event_interruptible_timeout(tty->write_wait,
226 !tty_chars_in_buffer(tty), timeout);
227 if (timeout <= 0)
228 return;
229
230 if (timeout == MAX_SCHEDULE_TIMEOUT)
231 timeout = 0;
232
233 if (tty->ops->wait_until_sent)
234 tty->ops->wait_until_sent(tty, timeout);
235 }
236 EXPORT_SYMBOL(tty_wait_until_sent);
237
238
239 /*
240 * Termios Helper Methods
241 */
242
unset_locked_termios(struct tty_struct * tty,struct ktermios * old)243 static void unset_locked_termios(struct tty_struct *tty, struct ktermios *old)
244 {
245 struct ktermios *termios = &tty->termios;
246 struct ktermios *locked = &tty->termios_locked;
247 int i;
248
249 #define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z)))
250
251 NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
252 NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
253 NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
254 NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
255 termios->c_line = locked->c_line ? old->c_line : termios->c_line;
256 for (i = 0; i < NCCS; i++)
257 termios->c_cc[i] = locked->c_cc[i] ?
258 old->c_cc[i] : termios->c_cc[i];
259 /* FIXME: What should we do for i/ospeed */
260 }
261
262 /**
263 * tty_termios_copy_hw - copy hardware settings
264 * @new: New termios
265 * @old: Old termios
266 *
267 * Propagate the hardware specific terminal setting bits from
268 * the old termios structure to the new one. This is used in cases
269 * where the hardware does not support reconfiguration or as a helper
270 * in some cases where only minimal reconfiguration is supported
271 */
272
tty_termios_copy_hw(struct ktermios * new,struct ktermios * old)273 void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
274 {
275 /* The bits a dumb device handles in software. Smart devices need
276 to always provide a set_termios method */
277 new->c_cflag &= HUPCL | CREAD | CLOCAL;
278 new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
279 new->c_ispeed = old->c_ispeed;
280 new->c_ospeed = old->c_ospeed;
281 }
282 EXPORT_SYMBOL(tty_termios_copy_hw);
283
284 /**
285 * tty_termios_hw_change - check for setting change
286 * @a: termios
287 * @b: termios to compare
288 *
289 * Check if any of the bits that affect a dumb device have changed
290 * between the two termios structures, or a speed change is needed.
291 */
292
tty_termios_hw_change(const struct ktermios * a,const struct ktermios * b)293 int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
294 {
295 if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed)
296 return 1;
297 if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL))
298 return 1;
299 return 0;
300 }
301 EXPORT_SYMBOL(tty_termios_hw_change);
302
303 /**
304 * tty_set_termios - update termios values
305 * @tty: tty to update
306 * @new_termios: desired new value
307 *
308 * Perform updates to the termios values set on this terminal.
309 * A master pty's termios should never be set.
310 *
311 * Locking: termios_rwsem
312 */
313
tty_set_termios(struct tty_struct * tty,struct ktermios * new_termios)314 int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios)
315 {
316 struct ktermios old_termios;
317 struct tty_ldisc *ld;
318
319 WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY &&
320 tty->driver->subtype == PTY_TYPE_MASTER);
321 /*
322 * Perform the actual termios internal changes under lock.
323 */
324
325
326 /* FIXME: we need to decide on some locking/ordering semantics
327 for the set_termios notification eventually */
328 down_write(&tty->termios_rwsem);
329 old_termios = tty->termios;
330 tty->termios = *new_termios;
331 unset_locked_termios(tty, &old_termios);
332
333 if (tty->ops->set_termios)
334 tty->ops->set_termios(tty, &old_termios);
335 else
336 tty_termios_copy_hw(&tty->termios, &old_termios);
337
338 ld = tty_ldisc_ref(tty);
339 if (ld != NULL) {
340 if (ld->ops->set_termios)
341 ld->ops->set_termios(tty, &old_termios);
342 tty_ldisc_deref(ld);
343 }
344 up_write(&tty->termios_rwsem);
345 return 0;
346 }
347 EXPORT_SYMBOL_GPL(tty_set_termios);
348
349 /**
350 * set_termios - set termios values for a tty
351 * @tty: terminal device
352 * @arg: user data
353 * @opt: option information
354 *
355 * Helper function to prepare termios data and run necessary other
356 * functions before using tty_set_termios to do the actual changes.
357 *
358 * Locking:
359 * Called functions take ldisc and termios_rwsem locks
360 */
361
set_termios(struct tty_struct * tty,void __user * arg,int opt)362 static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
363 {
364 struct ktermios tmp_termios;
365 struct tty_ldisc *ld;
366 int retval = tty_check_change(tty);
367
368 if (retval)
369 return retval;
370
371 down_read(&tty->termios_rwsem);
372 tmp_termios = tty->termios;
373 up_read(&tty->termios_rwsem);
374
375 if (opt & TERMIOS_TERMIO) {
376 if (user_termio_to_kernel_termios(&tmp_termios,
377 (struct termio __user *)arg))
378 return -EFAULT;
379 #ifdef TCGETS2
380 } else if (opt & TERMIOS_OLD) {
381 if (user_termios_to_kernel_termios_1(&tmp_termios,
382 (struct termios __user *)arg))
383 return -EFAULT;
384 } else {
385 if (user_termios_to_kernel_termios(&tmp_termios,
386 (struct termios2 __user *)arg))
387 return -EFAULT;
388 }
389 #else
390 } else if (user_termios_to_kernel_termios(&tmp_termios,
391 (struct termios __user *)arg))
392 return -EFAULT;
393 #endif
394
395 /* If old style Bfoo values are used then load c_ispeed/c_ospeed
396 * with the real speed so its unconditionally usable */
397 tmp_termios.c_ispeed = tty_termios_input_baud_rate(&tmp_termios);
398 tmp_termios.c_ospeed = tty_termios_baud_rate(&tmp_termios);
399
400 if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) {
401 retry_write_wait:
402 retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty));
403 if (retval < 0)
404 return retval;
405
406 if (tty_write_lock(tty, 0) < 0)
407 goto retry_write_wait;
408
409 /* Racing writer? */
410 if (tty_chars_in_buffer(tty)) {
411 tty_write_unlock(tty);
412 goto retry_write_wait;
413 }
414
415 ld = tty_ldisc_ref(tty);
416 if (ld != NULL) {
417 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
418 ld->ops->flush_buffer(tty);
419 tty_ldisc_deref(ld);
420 }
421
422 if ((opt & TERMIOS_WAIT) && tty->ops->wait_until_sent) {
423 tty->ops->wait_until_sent(tty, 0);
424 if (signal_pending(current)) {
425 tty_write_unlock(tty);
426 return -ERESTARTSYS;
427 }
428 }
429
430 tty_set_termios(tty, &tmp_termios);
431
432 tty_write_unlock(tty);
433 } else {
434 tty_set_termios(tty, &tmp_termios);
435 }
436
437 /* FIXME: Arguably if tmp_termios == tty->termios AND the
438 actual requested termios was not tmp_termios then we may
439 want to return an error as no user requested change has
440 succeeded */
441 return 0;
442 }
443
copy_termios(struct tty_struct * tty,struct ktermios * kterm)444 static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
445 {
446 down_read(&tty->termios_rwsem);
447 *kterm = tty->termios;
448 up_read(&tty->termios_rwsem);
449 }
450
copy_termios_locked(struct tty_struct * tty,struct ktermios * kterm)451 static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
452 {
453 down_read(&tty->termios_rwsem);
454 *kterm = tty->termios_locked;
455 up_read(&tty->termios_rwsem);
456 }
457
get_termio(struct tty_struct * tty,struct termio __user * termio)458 static int get_termio(struct tty_struct *tty, struct termio __user *termio)
459 {
460 struct ktermios kterm;
461 copy_termios(tty, &kterm);
462 if (kernel_termios_to_user_termio(termio, &kterm))
463 return -EFAULT;
464 return 0;
465 }
466
467
468 #ifdef TCGETX
469
470 /**
471 * set_termiox - set termiox fields if possible
472 * @tty: terminal
473 * @arg: termiox structure from user
474 * @opt: option flags for ioctl type
475 *
476 * Implement the device calling points for the SYS5 termiox ioctl
477 * interface in Linux
478 */
479
set_termiox(struct tty_struct * tty,void __user * arg,int opt)480 static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
481 {
482 struct termiox tnew;
483 struct tty_ldisc *ld;
484
485 if (tty->termiox == NULL)
486 return -EINVAL;
487 if (copy_from_user(&tnew, arg, sizeof(struct termiox)))
488 return -EFAULT;
489
490 ld = tty_ldisc_ref(tty);
491 if (ld != NULL) {
492 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
493 ld->ops->flush_buffer(tty);
494 tty_ldisc_deref(ld);
495 }
496 if (opt & TERMIOS_WAIT) {
497 tty_wait_until_sent(tty, 0);
498 if (signal_pending(current))
499 return -ERESTARTSYS;
500 }
501
502 down_write(&tty->termios_rwsem);
503 if (tty->ops->set_termiox)
504 tty->ops->set_termiox(tty, &tnew);
505 up_write(&tty->termios_rwsem);
506 return 0;
507 }
508
509 #endif
510
511
512 #ifdef TIOCGETP
513 /*
514 * These are deprecated, but there is limited support..
515 *
516 * The "sg_flags" translation is a joke..
517 */
get_sgflags(struct tty_struct * tty)518 static int get_sgflags(struct tty_struct *tty)
519 {
520 int flags = 0;
521
522 if (!L_ICANON(tty)) {
523 if (L_ISIG(tty))
524 flags |= 0x02; /* cbreak */
525 else
526 flags |= 0x20; /* raw */
527 }
528 if (L_ECHO(tty))
529 flags |= 0x08; /* echo */
530 if (O_OPOST(tty))
531 if (O_ONLCR(tty))
532 flags |= 0x10; /* crmod */
533 return flags;
534 }
535
get_sgttyb(struct tty_struct * tty,struct sgttyb __user * sgttyb)536 static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
537 {
538 struct sgttyb tmp;
539
540 down_read(&tty->termios_rwsem);
541 tmp.sg_ispeed = tty->termios.c_ispeed;
542 tmp.sg_ospeed = tty->termios.c_ospeed;
543 tmp.sg_erase = tty->termios.c_cc[VERASE];
544 tmp.sg_kill = tty->termios.c_cc[VKILL];
545 tmp.sg_flags = get_sgflags(tty);
546 up_read(&tty->termios_rwsem);
547
548 return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
549 }
550
set_sgflags(struct ktermios * termios,int flags)551 static void set_sgflags(struct ktermios *termios, int flags)
552 {
553 termios->c_iflag = ICRNL | IXON;
554 termios->c_oflag = 0;
555 termios->c_lflag = ISIG | ICANON;
556 if (flags & 0x02) { /* cbreak */
557 termios->c_iflag = 0;
558 termios->c_lflag &= ~ICANON;
559 }
560 if (flags & 0x08) { /* echo */
561 termios->c_lflag |= ECHO | ECHOE | ECHOK |
562 ECHOCTL | ECHOKE | IEXTEN;
563 }
564 if (flags & 0x10) { /* crmod */
565 termios->c_oflag |= OPOST | ONLCR;
566 }
567 if (flags & 0x20) { /* raw */
568 termios->c_iflag = 0;
569 termios->c_lflag &= ~(ISIG | ICANON);
570 }
571 if (!(termios->c_lflag & ICANON)) {
572 termios->c_cc[VMIN] = 1;
573 termios->c_cc[VTIME] = 0;
574 }
575 }
576
577 /**
578 * set_sgttyb - set legacy terminal values
579 * @tty: tty structure
580 * @sgttyb: pointer to old style terminal structure
581 *
582 * Updates a terminal from the legacy BSD style terminal information
583 * structure.
584 *
585 * Locking: termios_rwsem
586 */
587
set_sgttyb(struct tty_struct * tty,struct sgttyb __user * sgttyb)588 static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
589 {
590 int retval;
591 struct sgttyb tmp;
592 struct ktermios termios;
593
594 retval = tty_check_change(tty);
595 if (retval)
596 return retval;
597
598 if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
599 return -EFAULT;
600
601 down_write(&tty->termios_rwsem);
602 termios = tty->termios;
603 termios.c_cc[VERASE] = tmp.sg_erase;
604 termios.c_cc[VKILL] = tmp.sg_kill;
605 set_sgflags(&termios, tmp.sg_flags);
606 /* Try and encode into Bfoo format */
607 #ifdef BOTHER
608 tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
609 termios.c_ospeed);
610 #endif
611 up_write(&tty->termios_rwsem);
612 tty_set_termios(tty, &termios);
613 return 0;
614 }
615 #endif
616
617 #ifdef TIOCGETC
get_tchars(struct tty_struct * tty,struct tchars __user * tchars)618 static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
619 {
620 struct tchars tmp;
621
622 down_read(&tty->termios_rwsem);
623 tmp.t_intrc = tty->termios.c_cc[VINTR];
624 tmp.t_quitc = tty->termios.c_cc[VQUIT];
625 tmp.t_startc = tty->termios.c_cc[VSTART];
626 tmp.t_stopc = tty->termios.c_cc[VSTOP];
627 tmp.t_eofc = tty->termios.c_cc[VEOF];
628 tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */
629 up_read(&tty->termios_rwsem);
630 return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
631 }
632
set_tchars(struct tty_struct * tty,struct tchars __user * tchars)633 static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
634 {
635 struct tchars tmp;
636
637 if (copy_from_user(&tmp, tchars, sizeof(tmp)))
638 return -EFAULT;
639 down_write(&tty->termios_rwsem);
640 tty->termios.c_cc[VINTR] = tmp.t_intrc;
641 tty->termios.c_cc[VQUIT] = tmp.t_quitc;
642 tty->termios.c_cc[VSTART] = tmp.t_startc;
643 tty->termios.c_cc[VSTOP] = tmp.t_stopc;
644 tty->termios.c_cc[VEOF] = tmp.t_eofc;
645 tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
646 up_write(&tty->termios_rwsem);
647 return 0;
648 }
649 #endif
650
651 #ifdef TIOCGLTC
get_ltchars(struct tty_struct * tty,struct ltchars __user * ltchars)652 static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
653 {
654 struct ltchars tmp;
655
656 down_read(&tty->termios_rwsem);
657 tmp.t_suspc = tty->termios.c_cc[VSUSP];
658 /* what is dsuspc anyway? */
659 tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
660 tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
661 /* what is flushc anyway? */
662 tmp.t_flushc = tty->termios.c_cc[VEOL2];
663 tmp.t_werasc = tty->termios.c_cc[VWERASE];
664 tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
665 up_read(&tty->termios_rwsem);
666 return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
667 }
668
set_ltchars(struct tty_struct * tty,struct ltchars __user * ltchars)669 static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
670 {
671 struct ltchars tmp;
672
673 if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
674 return -EFAULT;
675
676 down_write(&tty->termios_rwsem);
677 tty->termios.c_cc[VSUSP] = tmp.t_suspc;
678 /* what is dsuspc anyway? */
679 tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
680 tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
681 /* what is flushc anyway? */
682 tty->termios.c_cc[VEOL2] = tmp.t_flushc;
683 tty->termios.c_cc[VWERASE] = tmp.t_werasc;
684 tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
685 up_write(&tty->termios_rwsem);
686 return 0;
687 }
688 #endif
689
690 /**
691 * tty_change_softcar - carrier change ioctl helper
692 * @tty: tty to update
693 * @arg: enable/disable CLOCAL
694 *
695 * Perform a change to the CLOCAL state and call into the driver
696 * layer to make it visible. All done with the termios rwsem
697 */
698
tty_change_softcar(struct tty_struct * tty,int arg)699 static int tty_change_softcar(struct tty_struct *tty, int arg)
700 {
701 int ret = 0;
702 int bit = arg ? CLOCAL : 0;
703 struct ktermios old;
704
705 down_write(&tty->termios_rwsem);
706 old = tty->termios;
707 tty->termios.c_cflag &= ~CLOCAL;
708 tty->termios.c_cflag |= bit;
709 if (tty->ops->set_termios)
710 tty->ops->set_termios(tty, &old);
711 if (C_CLOCAL(tty) != bit)
712 ret = -EINVAL;
713 up_write(&tty->termios_rwsem);
714 return ret;
715 }
716
717 /**
718 * tty_mode_ioctl - mode related ioctls
719 * @tty: tty for the ioctl
720 * @file: file pointer for the tty
721 * @cmd: command
722 * @arg: ioctl argument
723 *
724 * Perform non line discipline specific mode control ioctls. This
725 * is designed to be called by line disciplines to ensure they provide
726 * consistent mode setting.
727 */
728
tty_mode_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)729 int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
730 unsigned int cmd, unsigned long arg)
731 {
732 struct tty_struct *real_tty;
733 void __user *p = (void __user *)arg;
734 int ret = 0;
735 struct ktermios kterm;
736
737 BUG_ON(file == NULL);
738
739 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
740 tty->driver->subtype == PTY_TYPE_MASTER)
741 real_tty = tty->link;
742 else
743 real_tty = tty;
744
745 switch (cmd) {
746 #ifdef TIOCGETP
747 case TIOCGETP:
748 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
749 case TIOCSETP:
750 case TIOCSETN:
751 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
752 #endif
753 #ifdef TIOCGETC
754 case TIOCGETC:
755 return get_tchars(real_tty, p);
756 case TIOCSETC:
757 return set_tchars(real_tty, p);
758 #endif
759 #ifdef TIOCGLTC
760 case TIOCGLTC:
761 return get_ltchars(real_tty, p);
762 case TIOCSLTC:
763 return set_ltchars(real_tty, p);
764 #endif
765 case TCSETSF:
766 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
767 case TCSETSW:
768 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
769 case TCSETS:
770 return set_termios(real_tty, p, TERMIOS_OLD);
771 #ifndef TCGETS2
772 case TCGETS:
773 copy_termios(real_tty, &kterm);
774 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
775 ret = -EFAULT;
776 return ret;
777 #else
778 case TCGETS:
779 copy_termios(real_tty, &kterm);
780 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
781 ret = -EFAULT;
782 return ret;
783 case TCGETS2:
784 copy_termios(real_tty, &kterm);
785 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
786 ret = -EFAULT;
787 return ret;
788 case TCSETSF2:
789 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
790 case TCSETSW2:
791 return set_termios(real_tty, p, TERMIOS_WAIT);
792 case TCSETS2:
793 return set_termios(real_tty, p, 0);
794 #endif
795 case TCGETA:
796 return get_termio(real_tty, p);
797 case TCSETAF:
798 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
799 case TCSETAW:
800 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
801 case TCSETA:
802 return set_termios(real_tty, p, TERMIOS_TERMIO);
803 #ifndef TCGETS2
804 case TIOCGLCKTRMIOS:
805 copy_termios_locked(real_tty, &kterm);
806 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
807 ret = -EFAULT;
808 return ret;
809 case TIOCSLCKTRMIOS:
810 if (!capable(CAP_SYS_ADMIN))
811 return -EPERM;
812 copy_termios_locked(real_tty, &kterm);
813 if (user_termios_to_kernel_termios(&kterm,
814 (struct termios __user *) arg))
815 return -EFAULT;
816 down_write(&real_tty->termios_rwsem);
817 real_tty->termios_locked = kterm;
818 up_write(&real_tty->termios_rwsem);
819 return 0;
820 #else
821 case TIOCGLCKTRMIOS:
822 copy_termios_locked(real_tty, &kterm);
823 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
824 ret = -EFAULT;
825 return ret;
826 case TIOCSLCKTRMIOS:
827 if (!capable(CAP_SYS_ADMIN))
828 return -EPERM;
829 copy_termios_locked(real_tty, &kterm);
830 if (user_termios_to_kernel_termios_1(&kterm,
831 (struct termios __user *) arg))
832 return -EFAULT;
833 down_write(&real_tty->termios_rwsem);
834 real_tty->termios_locked = kterm;
835 up_write(&real_tty->termios_rwsem);
836 return ret;
837 #endif
838 #ifdef TCGETX
839 case TCGETX: {
840 struct termiox ktermx;
841 if (real_tty->termiox == NULL)
842 return -EINVAL;
843 down_read(&real_tty->termios_rwsem);
844 memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
845 up_read(&real_tty->termios_rwsem);
846 if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
847 ret = -EFAULT;
848 return ret;
849 }
850 case TCSETX:
851 return set_termiox(real_tty, p, 0);
852 case TCSETXW:
853 return set_termiox(real_tty, p, TERMIOS_WAIT);
854 case TCSETXF:
855 return set_termiox(real_tty, p, TERMIOS_FLUSH);
856 #endif
857 case TIOCGSOFTCAR:
858 copy_termios(real_tty, &kterm);
859 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
860 (int __user *)arg);
861 return ret;
862 case TIOCSSOFTCAR:
863 if (get_user(arg, (unsigned int __user *) arg))
864 return -EFAULT;
865 return tty_change_softcar(real_tty, arg);
866 default:
867 return -ENOIOCTLCMD;
868 }
869 }
870 EXPORT_SYMBOL_GPL(tty_mode_ioctl);
871
872
873 /* Caller guarantees ldisc reference is held */
__tty_perform_flush(struct tty_struct * tty,unsigned long arg)874 static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
875 {
876 struct tty_ldisc *ld = tty->ldisc;
877
878 switch (arg) {
879 case TCIFLUSH:
880 if (ld && ld->ops->flush_buffer) {
881 ld->ops->flush_buffer(tty);
882 tty_unthrottle(tty);
883 }
884 break;
885 case TCIOFLUSH:
886 if (ld && ld->ops->flush_buffer) {
887 ld->ops->flush_buffer(tty);
888 tty_unthrottle(tty);
889 }
890 /* fall through */
891 case TCOFLUSH:
892 tty_driver_flush_buffer(tty);
893 break;
894 default:
895 return -EINVAL;
896 }
897 return 0;
898 }
899
tty_perform_flush(struct tty_struct * tty,unsigned long arg)900 int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
901 {
902 struct tty_ldisc *ld;
903 int retval = tty_check_change(tty);
904 if (retval)
905 return retval;
906
907 ld = tty_ldisc_ref_wait(tty);
908 retval = __tty_perform_flush(tty, arg);
909 if (ld)
910 tty_ldisc_deref(ld);
911 return retval;
912 }
913 EXPORT_SYMBOL_GPL(tty_perform_flush);
914
n_tty_ioctl_helper(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)915 int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
916 unsigned int cmd, unsigned long arg)
917 {
918 int retval;
919
920 switch (cmd) {
921 case TCXONC:
922 retval = tty_check_change(tty);
923 if (retval)
924 return retval;
925 switch (arg) {
926 case TCOOFF:
927 spin_lock_irq(&tty->flow_lock);
928 if (!tty->flow_stopped) {
929 tty->flow_stopped = 1;
930 __stop_tty(tty);
931 }
932 spin_unlock_irq(&tty->flow_lock);
933 break;
934 case TCOON:
935 spin_lock_irq(&tty->flow_lock);
936 if (tty->flow_stopped) {
937 tty->flow_stopped = 0;
938 __start_tty(tty);
939 }
940 spin_unlock_irq(&tty->flow_lock);
941 break;
942 case TCIOFF:
943 if (STOP_CHAR(tty) != __DISABLED_CHAR)
944 retval = tty_send_xchar(tty, STOP_CHAR(tty));
945 break;
946 case TCION:
947 if (START_CHAR(tty) != __DISABLED_CHAR)
948 retval = tty_send_xchar(tty, START_CHAR(tty));
949 break;
950 default:
951 return -EINVAL;
952 }
953 return retval;
954 case TCFLSH:
955 retval = tty_check_change(tty);
956 if (retval)
957 return retval;
958 return __tty_perform_flush(tty, arg);
959 default:
960 /* Try the mode commands */
961 return tty_mode_ioctl(tty, file, cmd, arg);
962 }
963 }
964 EXPORT_SYMBOL(n_tty_ioctl_helper);
965