1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
4 | * |
5 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines |
6 | * which can be dynamically activated and de-activated by the line |
7 | * discipline handling modules (like SLIP). |
8 | */ |
9 | |
10 | #include <linux/bits.h> |
11 | #include <linux/types.h> |
12 | #include <linux/termios.h> |
13 | #include <linux/errno.h> |
14 | #include <linux/sched/signal.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/major.h> |
17 | #include <linux/tty.h> |
18 | #include <linux/fcntl.h> |
19 | #include <linux/string.h> |
20 | #include <linux/mm.h> |
21 | #include <linux/module.h> |
22 | #include <linux/bitops.h> |
23 | #include <linux/mutex.h> |
24 | #include <linux/compat.h> |
25 | #include <linux/termios_internal.h> |
26 | #include "tty.h" |
27 | |
28 | #include <asm/io.h> |
29 | #include <linux/uaccess.h> |
30 | |
31 | #undef DEBUG |
32 | |
33 | /* |
34 | * Internal flag options for termios setting behavior |
35 | */ |
36 | #define TERMIOS_FLUSH BIT(0) |
37 | #define TERMIOS_WAIT BIT(1) |
38 | #define TERMIOS_TERMIO BIT(2) |
39 | #define TERMIOS_OLD BIT(3) |
40 | |
41 | /** |
42 | * tty_chars_in_buffer - characters pending |
43 | * @tty: terminal |
44 | * |
45 | * Returns: the number of bytes of data in the device private output queue. If |
46 | * no private method is supplied there is assumed to be no queue on the device. |
47 | */ |
48 | unsigned int tty_chars_in_buffer(struct tty_struct *tty) |
49 | { |
50 | if (tty->ops->chars_in_buffer) |
51 | return tty->ops->chars_in_buffer(tty); |
52 | return 0; |
53 | } |
54 | EXPORT_SYMBOL(tty_chars_in_buffer); |
55 | |
56 | /** |
57 | * tty_write_room - write queue space |
58 | * @tty: terminal |
59 | * |
60 | * Returns: the number of bytes that can be queued to this device at the present |
61 | * time. The result should be treated as a guarantee and the driver cannot |
62 | * offer a value it later shrinks by more than the number of bytes written. If |
63 | * no method is provided, 2K is always returned and data may be lost as there |
64 | * will be no flow control. |
65 | */ |
66 | unsigned int tty_write_room(struct tty_struct *tty) |
67 | { |
68 | if (tty->ops->write_room) |
69 | return tty->ops->write_room(tty); |
70 | return 2048; |
71 | } |
72 | EXPORT_SYMBOL(tty_write_room); |
73 | |
74 | /** |
75 | * tty_driver_flush_buffer - discard internal buffer |
76 | * @tty: terminal |
77 | * |
78 | * Discard the internal output buffer for this device. If no method is provided, |
79 | * then either the buffer cannot be hardware flushed or there is no buffer |
80 | * driver side. |
81 | */ |
82 | void tty_driver_flush_buffer(struct tty_struct *tty) |
83 | { |
84 | if (tty->ops->flush_buffer) |
85 | tty->ops->flush_buffer(tty); |
86 | } |
87 | EXPORT_SYMBOL(tty_driver_flush_buffer); |
88 | |
89 | /** |
90 | * tty_unthrottle - flow control |
91 | * @tty: terminal |
92 | * |
93 | * Indicate that a @tty may continue transmitting data down the stack. Takes |
94 | * the &tty_struct->termios_rwsem to protect against parallel |
95 | * throttle/unthrottle and also to ensure the driver can consistently reference |
96 | * its own termios data at this point when implementing software flow control. |
97 | * |
98 | * Drivers should however remember that the stack can issue a throttle, then |
99 | * change flow control method, then unthrottle. |
100 | */ |
101 | void tty_unthrottle(struct tty_struct *tty) |
102 | { |
103 | down_write(sem: &tty->termios_rwsem); |
104 | if (test_and_clear_bit(TTY_THROTTLED, addr: &tty->flags) && |
105 | tty->ops->unthrottle) |
106 | tty->ops->unthrottle(tty); |
107 | tty->flow_change = TTY_FLOW_NO_CHANGE; |
108 | up_write(sem: &tty->termios_rwsem); |
109 | } |
110 | EXPORT_SYMBOL(tty_unthrottle); |
111 | |
112 | /** |
113 | * tty_throttle_safe - flow control |
114 | * @tty: terminal |
115 | * |
116 | * Indicate that a @tty should stop transmitting data down the stack. |
117 | * tty_throttle_safe() will only attempt throttle if @tty->flow_change is |
118 | * %TTY_THROTTLE_SAFE. Prevents an accidental throttle due to race conditions |
119 | * when throttling is conditional on factors evaluated prior to throttling. |
120 | * |
121 | * Returns: %true if @tty is throttled (or was already throttled) |
122 | */ |
123 | bool tty_throttle_safe(struct tty_struct *tty) |
124 | { |
125 | bool ret = true; |
126 | |
127 | mutex_lock(&tty->throttle_mutex); |
128 | if (!tty_throttled(tty)) { |
129 | if (tty->flow_change != TTY_THROTTLE_SAFE) |
130 | ret = false; |
131 | else { |
132 | set_bit(TTY_THROTTLED, addr: &tty->flags); |
133 | if (tty->ops->throttle) |
134 | tty->ops->throttle(tty); |
135 | } |
136 | } |
137 | mutex_unlock(lock: &tty->throttle_mutex); |
138 | |
139 | return ret; |
140 | } |
141 | |
142 | /** |
143 | * tty_unthrottle_safe - flow control |
144 | * @tty: terminal |
145 | * |
146 | * Similar to tty_unthrottle() but will only attempt unthrottle if |
147 | * @tty->flow_change is %TTY_UNTHROTTLE_SAFE. Prevents an accidental unthrottle |
148 | * due to race conditions when unthrottling is conditional on factors evaluated |
149 | * prior to unthrottling. |
150 | * |
151 | * Returns: %true if @tty is unthrottled (or was already unthrottled) |
152 | */ |
153 | bool tty_unthrottle_safe(struct tty_struct *tty) |
154 | { |
155 | bool ret = true; |
156 | |
157 | mutex_lock(&tty->throttle_mutex); |
158 | if (tty_throttled(tty)) { |
159 | if (tty->flow_change != TTY_UNTHROTTLE_SAFE) |
160 | ret = false; |
161 | else { |
162 | clear_bit(TTY_THROTTLED, addr: &tty->flags); |
163 | if (tty->ops->unthrottle) |
164 | tty->ops->unthrottle(tty); |
165 | } |
166 | } |
167 | mutex_unlock(lock: &tty->throttle_mutex); |
168 | |
169 | return ret; |
170 | } |
171 | |
172 | /** |
173 | * tty_wait_until_sent - wait for I/O to finish |
174 | * @tty: tty we are waiting for |
175 | * @timeout: how long we will wait |
176 | * |
177 | * Wait for characters pending in a tty driver to hit the wire, or for a |
178 | * timeout to occur (eg due to flow control). |
179 | * |
180 | * Locking: none |
181 | */ |
182 | |
183 | void tty_wait_until_sent(struct tty_struct *tty, long timeout) |
184 | { |
185 | if (!timeout) |
186 | timeout = MAX_SCHEDULE_TIMEOUT; |
187 | |
188 | timeout = wait_event_interruptible_timeout(tty->write_wait, |
189 | !tty_chars_in_buffer(tty), timeout); |
190 | if (timeout <= 0) |
191 | return; |
192 | |
193 | if (timeout == MAX_SCHEDULE_TIMEOUT) |
194 | timeout = 0; |
195 | |
196 | if (tty->ops->wait_until_sent) |
197 | tty->ops->wait_until_sent(tty, timeout); |
198 | } |
199 | EXPORT_SYMBOL(tty_wait_until_sent); |
200 | |
201 | |
202 | /* |
203 | * Termios Helper Methods |
204 | */ |
205 | |
206 | static void unset_locked_termios(struct tty_struct *tty, const struct ktermios *old) |
207 | { |
208 | struct ktermios *termios = &tty->termios; |
209 | struct ktermios *locked = &tty->termios_locked; |
210 | int i; |
211 | |
212 | #define NOSET_MASK(x, y, z) (x = ((x) & ~(z)) | ((y) & (z))) |
213 | |
214 | NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag); |
215 | NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag); |
216 | NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag); |
217 | NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag); |
218 | termios->c_line = locked->c_line ? old->c_line : termios->c_line; |
219 | for (i = 0; i < NCCS; i++) |
220 | termios->c_cc[i] = locked->c_cc[i] ? |
221 | old->c_cc[i] : termios->c_cc[i]; |
222 | /* FIXME: What should we do for i/ospeed */ |
223 | } |
224 | |
225 | /** |
226 | * tty_termios_copy_hw - copy hardware settings |
227 | * @new: new termios |
228 | * @old: old termios |
229 | * |
230 | * Propagate the hardware specific terminal setting bits from the @old termios |
231 | * structure to the @new one. This is used in cases where the hardware does not |
232 | * support reconfiguration or as a helper in some cases where only minimal |
233 | * reconfiguration is supported. |
234 | */ |
235 | void tty_termios_copy_hw(struct ktermios *new, const struct ktermios *old) |
236 | { |
237 | /* The bits a dumb device handles in software. Smart devices need |
238 | to always provide a set_termios method */ |
239 | new->c_cflag &= HUPCL | CREAD | CLOCAL; |
240 | new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL); |
241 | new->c_ispeed = old->c_ispeed; |
242 | new->c_ospeed = old->c_ospeed; |
243 | } |
244 | EXPORT_SYMBOL(tty_termios_copy_hw); |
245 | |
246 | /** |
247 | * tty_termios_hw_change - check for setting change |
248 | * @a: termios |
249 | * @b: termios to compare |
250 | * |
251 | * Check if any of the bits that affect a dumb device have changed between the |
252 | * two termios structures, or a speed change is needed. |
253 | * |
254 | * Returns: %true if change is needed |
255 | */ |
256 | bool tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b) |
257 | { |
258 | if (a->c_ispeed != b->c_ispeed || a->c_ospeed != b->c_ospeed) |
259 | return true; |
260 | if ((a->c_cflag ^ b->c_cflag) & ~(HUPCL | CREAD | CLOCAL)) |
261 | return true; |
262 | return false; |
263 | } |
264 | EXPORT_SYMBOL(tty_termios_hw_change); |
265 | |
266 | /** |
267 | * tty_get_char_size - get size of a character |
268 | * @cflag: termios cflag value |
269 | * |
270 | * Returns: size (in bits) of a character depending on @cflag's %CSIZE setting |
271 | */ |
272 | unsigned char tty_get_char_size(unsigned int cflag) |
273 | { |
274 | switch (cflag & CSIZE) { |
275 | case CS5: |
276 | return 5; |
277 | case CS6: |
278 | return 6; |
279 | case CS7: |
280 | return 7; |
281 | case CS8: |
282 | default: |
283 | return 8; |
284 | } |
285 | } |
286 | EXPORT_SYMBOL_GPL(tty_get_char_size); |
287 | |
288 | /** |
289 | * tty_get_frame_size - get size of a frame |
290 | * @cflag: termios cflag value |
291 | * |
292 | * Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB, and |
293 | * %PARENB setting. The result is a sum of character size, start and stop bits |
294 | * -- one bit each -- second stop bit (if set), and parity bit (if set). |
295 | * |
296 | * Returns: size (in bits) of a frame depending on @cflag's setting. |
297 | */ |
298 | unsigned char tty_get_frame_size(unsigned int cflag) |
299 | { |
300 | unsigned char bits = 2 + tty_get_char_size(cflag); |
301 | |
302 | if (cflag & CSTOPB) |
303 | bits++; |
304 | if (cflag & PARENB) |
305 | bits++; |
306 | if (cflag & ADDRB) |
307 | bits++; |
308 | |
309 | return bits; |
310 | } |
311 | EXPORT_SYMBOL_GPL(tty_get_frame_size); |
312 | |
313 | /** |
314 | * tty_set_termios - update termios values |
315 | * @tty: tty to update |
316 | * @new_termios: desired new value |
317 | * |
318 | * Perform updates to the termios values set on this @tty. A master pty's |
319 | * termios should never be set. |
320 | * |
321 | * Locking: &tty_struct->termios_rwsem |
322 | */ |
323 | int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios) |
324 | { |
325 | struct ktermios old_termios; |
326 | struct tty_ldisc *ld; |
327 | |
328 | WARN_ON(tty->driver->type == TTY_DRIVER_TYPE_PTY && |
329 | tty->driver->subtype == PTY_TYPE_MASTER); |
330 | /* |
331 | * Perform the actual termios internal changes under lock. |
332 | */ |
333 | |
334 | |
335 | /* FIXME: we need to decide on some locking/ordering semantics |
336 | for the set_termios notification eventually */ |
337 | down_write(sem: &tty->termios_rwsem); |
338 | old_termios = tty->termios; |
339 | tty->termios = *new_termios; |
340 | unset_locked_termios(tty, old: &old_termios); |
341 | /* Reset any ADDRB changes, ADDRB is changed through ->rs485_config() */ |
342 | tty->termios.c_cflag ^= (tty->termios.c_cflag ^ old_termios.c_cflag) & ADDRB; |
343 | |
344 | if (tty->ops->set_termios) |
345 | tty->ops->set_termios(tty, &old_termios); |
346 | else |
347 | tty_termios_copy_hw(&tty->termios, &old_termios); |
348 | |
349 | ld = tty_ldisc_ref(tty); |
350 | if (ld != NULL) { |
351 | if (ld->ops->set_termios) |
352 | ld->ops->set_termios(tty, &old_termios); |
353 | tty_ldisc_deref(ld); |
354 | } |
355 | up_write(sem: &tty->termios_rwsem); |
356 | return 0; |
357 | } |
358 | EXPORT_SYMBOL_GPL(tty_set_termios); |
359 | |
360 | |
361 | /* |
362 | * Translate a "termio" structure into a "termios". Ugh. |
363 | */ |
364 | __weak int user_termio_to_kernel_termios(struct ktermios *termios, |
365 | struct termio __user *termio) |
366 | { |
367 | struct termio v; |
368 | |
369 | if (copy_from_user(to: &v, from: termio, n: sizeof(struct termio))) |
370 | return -EFAULT; |
371 | |
372 | termios->c_iflag = (0xffff0000 & termios->c_iflag) | v.c_iflag; |
373 | termios->c_oflag = (0xffff0000 & termios->c_oflag) | v.c_oflag; |
374 | termios->c_cflag = (0xffff0000 & termios->c_cflag) | v.c_cflag; |
375 | termios->c_lflag = (0xffff0000 & termios->c_lflag) | v.c_lflag; |
376 | termios->c_line = (0xffff0000 & termios->c_lflag) | v.c_line; |
377 | memcpy(termios->c_cc, v.c_cc, NCC); |
378 | return 0; |
379 | } |
380 | |
381 | /* |
382 | * Translate a "termios" structure into a "termio". Ugh. |
383 | */ |
384 | __weak int kernel_termios_to_user_termio(struct termio __user *termio, |
385 | struct ktermios *termios) |
386 | { |
387 | struct termio v; |
388 | memset(&v, 0, sizeof(struct termio)); |
389 | v.c_iflag = termios->c_iflag; |
390 | v.c_oflag = termios->c_oflag; |
391 | v.c_cflag = termios->c_cflag; |
392 | v.c_lflag = termios->c_lflag; |
393 | v.c_line = termios->c_line; |
394 | memcpy(v.c_cc, termios->c_cc, NCC); |
395 | return copy_to_user(to: termio, from: &v, n: sizeof(struct termio)); |
396 | } |
397 | |
398 | #ifdef TCGETS2 |
399 | __weak int user_termios_to_kernel_termios(struct ktermios *k, |
400 | struct termios2 __user *u) |
401 | { |
402 | return copy_from_user(to: k, from: u, n: sizeof(struct termios2)); |
403 | } |
404 | __weak int kernel_termios_to_user_termios(struct termios2 __user *u, |
405 | struct ktermios *k) |
406 | { |
407 | return copy_to_user(to: u, from: k, n: sizeof(struct termios2)); |
408 | } |
409 | __weak int user_termios_to_kernel_termios_1(struct ktermios *k, |
410 | struct termios __user *u) |
411 | { |
412 | return copy_from_user(to: k, from: u, n: sizeof(struct termios)); |
413 | } |
414 | __weak int kernel_termios_to_user_termios_1(struct termios __user *u, |
415 | struct ktermios *k) |
416 | { |
417 | return copy_to_user(to: u, from: k, n: sizeof(struct termios)); |
418 | } |
419 | |
420 | #else |
421 | |
422 | __weak int user_termios_to_kernel_termios(struct ktermios *k, |
423 | struct termios __user *u) |
424 | { |
425 | return copy_from_user(k, u, sizeof(struct termios)); |
426 | } |
427 | __weak int kernel_termios_to_user_termios(struct termios __user *u, |
428 | struct ktermios *k) |
429 | { |
430 | return copy_to_user(u, k, sizeof(struct termios)); |
431 | } |
432 | #endif /* TCGETS2 */ |
433 | |
434 | /** |
435 | * set_termios - set termios values for a tty |
436 | * @tty: terminal device |
437 | * @arg: user data |
438 | * @opt: option information |
439 | * |
440 | * Helper function to prepare termios data and run necessary other functions |
441 | * before using tty_set_termios() to do the actual changes. |
442 | * |
443 | * Locking: called functions take &tty_struct->ldisc_sem and |
444 | * &tty_struct->termios_rwsem locks |
445 | * |
446 | * Returns: 0 on success, an error otherwise |
447 | */ |
448 | static int set_termios(struct tty_struct *tty, void __user *arg, int opt) |
449 | { |
450 | struct ktermios tmp_termios; |
451 | struct tty_ldisc *ld; |
452 | int retval = tty_check_change(tty); |
453 | |
454 | if (retval) |
455 | return retval; |
456 | |
457 | down_read(sem: &tty->termios_rwsem); |
458 | tmp_termios = tty->termios; |
459 | up_read(sem: &tty->termios_rwsem); |
460 | |
461 | if (opt & TERMIOS_TERMIO) { |
462 | if (user_termio_to_kernel_termios(termios: &tmp_termios, |
463 | termio: (struct termio __user *)arg)) |
464 | return -EFAULT; |
465 | #ifdef TCGETS2 |
466 | } else if (opt & TERMIOS_OLD) { |
467 | if (user_termios_to_kernel_termios_1(k: &tmp_termios, |
468 | u: (struct termios __user *)arg)) |
469 | return -EFAULT; |
470 | } else { |
471 | if (user_termios_to_kernel_termios(k: &tmp_termios, |
472 | u: (struct termios2 __user *)arg)) |
473 | return -EFAULT; |
474 | } |
475 | #else |
476 | } else if (user_termios_to_kernel_termios(&tmp_termios, |
477 | (struct termios __user *)arg)) |
478 | return -EFAULT; |
479 | #endif |
480 | |
481 | /* If old style Bfoo values are used then load c_ispeed/c_ospeed |
482 | * with the real speed so its unconditionally usable */ |
483 | tmp_termios.c_ispeed = tty_termios_input_baud_rate(termios: &tmp_termios); |
484 | tmp_termios.c_ospeed = tty_termios_baud_rate(termios: &tmp_termios); |
485 | |
486 | if (opt & (TERMIOS_FLUSH|TERMIOS_WAIT)) { |
487 | retry_write_wait: |
488 | retval = wait_event_interruptible(tty->write_wait, !tty_chars_in_buffer(tty)); |
489 | if (retval < 0) |
490 | return retval; |
491 | |
492 | if (tty_write_lock(tty, ndelay: false) < 0) |
493 | goto retry_write_wait; |
494 | |
495 | /* Racing writer? */ |
496 | if (tty_chars_in_buffer(tty)) { |
497 | tty_write_unlock(tty); |
498 | goto retry_write_wait; |
499 | } |
500 | |
501 | ld = tty_ldisc_ref(tty); |
502 | if (ld != NULL) { |
503 | if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer) |
504 | ld->ops->flush_buffer(tty); |
505 | tty_ldisc_deref(ld); |
506 | } |
507 | |
508 | if ((opt & TERMIOS_WAIT) && tty->ops->wait_until_sent) { |
509 | tty->ops->wait_until_sent(tty, 0); |
510 | if (signal_pending(current)) { |
511 | tty_write_unlock(tty); |
512 | return -ERESTARTSYS; |
513 | } |
514 | } |
515 | |
516 | tty_set_termios(tty, &tmp_termios); |
517 | |
518 | tty_write_unlock(tty); |
519 | } else { |
520 | tty_set_termios(tty, &tmp_termios); |
521 | } |
522 | |
523 | /* FIXME: Arguably if tmp_termios == tty->termios AND the |
524 | actual requested termios was not tmp_termios then we may |
525 | want to return an error as no user requested change has |
526 | succeeded */ |
527 | return 0; |
528 | } |
529 | |
530 | static void copy_termios(struct tty_struct *tty, struct ktermios *kterm) |
531 | { |
532 | down_read(sem: &tty->termios_rwsem); |
533 | *kterm = tty->termios; |
534 | up_read(sem: &tty->termios_rwsem); |
535 | } |
536 | |
537 | static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm) |
538 | { |
539 | down_read(sem: &tty->termios_rwsem); |
540 | *kterm = tty->termios_locked; |
541 | up_read(sem: &tty->termios_rwsem); |
542 | } |
543 | |
544 | static int get_termio(struct tty_struct *tty, struct termio __user *termio) |
545 | { |
546 | struct ktermios kterm; |
547 | copy_termios(tty, kterm: &kterm); |
548 | if (kernel_termios_to_user_termio(termio, termios: &kterm)) |
549 | return -EFAULT; |
550 | return 0; |
551 | } |
552 | |
553 | #ifdef TIOCGETP |
554 | /* |
555 | * These are deprecated, but there is limited support.. |
556 | * |
557 | * The "sg_flags" translation is a joke.. |
558 | */ |
559 | static int get_sgflags(struct tty_struct *tty) |
560 | { |
561 | int flags = 0; |
562 | |
563 | if (!L_ICANON(tty)) { |
564 | if (L_ISIG(tty)) |
565 | flags |= 0x02; /* cbreak */ |
566 | else |
567 | flags |= 0x20; /* raw */ |
568 | } |
569 | if (L_ECHO(tty)) |
570 | flags |= 0x08; /* echo */ |
571 | if (O_OPOST(tty)) |
572 | if (O_ONLCR(tty)) |
573 | flags |= 0x10; /* crmod */ |
574 | return flags; |
575 | } |
576 | |
577 | static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb) |
578 | { |
579 | struct sgttyb tmp; |
580 | |
581 | down_read(&tty->termios_rwsem); |
582 | tmp.sg_ispeed = tty->termios.c_ispeed; |
583 | tmp.sg_ospeed = tty->termios.c_ospeed; |
584 | tmp.sg_erase = tty->termios.c_cc[VERASE]; |
585 | tmp.sg_kill = tty->termios.c_cc[VKILL]; |
586 | tmp.sg_flags = get_sgflags(tty); |
587 | up_read(&tty->termios_rwsem); |
588 | |
589 | return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0; |
590 | } |
591 | |
592 | static void set_sgflags(struct ktermios *termios, int flags) |
593 | { |
594 | termios->c_iflag = ICRNL | IXON; |
595 | termios->c_oflag = 0; |
596 | termios->c_lflag = ISIG | ICANON; |
597 | if (flags & 0x02) { /* cbreak */ |
598 | termios->c_iflag = 0; |
599 | termios->c_lflag &= ~ICANON; |
600 | } |
601 | if (flags & 0x08) { /* echo */ |
602 | termios->c_lflag |= ECHO | ECHOE | ECHOK | |
603 | ECHOCTL | ECHOKE | IEXTEN; |
604 | } |
605 | if (flags & 0x10) { /* crmod */ |
606 | termios->c_oflag |= OPOST | ONLCR; |
607 | } |
608 | if (flags & 0x20) { /* raw */ |
609 | termios->c_iflag = 0; |
610 | termios->c_lflag &= ~(ISIG | ICANON); |
611 | } |
612 | if (!(termios->c_lflag & ICANON)) { |
613 | termios->c_cc[VMIN] = 1; |
614 | termios->c_cc[VTIME] = 0; |
615 | } |
616 | } |
617 | |
618 | /** |
619 | * set_sgttyb - set legacy terminal values |
620 | * @tty: tty structure |
621 | * @sgttyb: pointer to old style terminal structure |
622 | * |
623 | * Updates a terminal from the legacy BSD style terminal information structure. |
624 | * |
625 | * Locking: &tty_struct->termios_rwsem |
626 | * |
627 | * Returns: 0 on success, an error otherwise |
628 | */ |
629 | static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb) |
630 | { |
631 | int retval; |
632 | struct sgttyb tmp; |
633 | struct ktermios termios; |
634 | |
635 | retval = tty_check_change(tty); |
636 | if (retval) |
637 | return retval; |
638 | |
639 | if (copy_from_user(&tmp, sgttyb, sizeof(tmp))) |
640 | return -EFAULT; |
641 | |
642 | down_write(&tty->termios_rwsem); |
643 | termios = tty->termios; |
644 | termios.c_cc[VERASE] = tmp.sg_erase; |
645 | termios.c_cc[VKILL] = tmp.sg_kill; |
646 | set_sgflags(&termios, tmp.sg_flags); |
647 | /* Try and encode into Bfoo format */ |
648 | tty_termios_encode_baud_rate(&termios, termios.c_ispeed, |
649 | termios.c_ospeed); |
650 | up_write(&tty->termios_rwsem); |
651 | tty_set_termios(tty, &termios); |
652 | return 0; |
653 | } |
654 | #endif |
655 | |
656 | #ifdef TIOCGETC |
657 | static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars) |
658 | { |
659 | struct tchars tmp; |
660 | |
661 | down_read(&tty->termios_rwsem); |
662 | tmp.t_intrc = tty->termios.c_cc[VINTR]; |
663 | tmp.t_quitc = tty->termios.c_cc[VQUIT]; |
664 | tmp.t_startc = tty->termios.c_cc[VSTART]; |
665 | tmp.t_stopc = tty->termios.c_cc[VSTOP]; |
666 | tmp.t_eofc = tty->termios.c_cc[VEOF]; |
667 | tmp.t_brkc = tty->termios.c_cc[VEOL2]; /* what is brkc anyway? */ |
668 | up_read(&tty->termios_rwsem); |
669 | return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; |
670 | } |
671 | |
672 | static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars) |
673 | { |
674 | struct tchars tmp; |
675 | |
676 | if (copy_from_user(&tmp, tchars, sizeof(tmp))) |
677 | return -EFAULT; |
678 | down_write(&tty->termios_rwsem); |
679 | tty->termios.c_cc[VINTR] = tmp.t_intrc; |
680 | tty->termios.c_cc[VQUIT] = tmp.t_quitc; |
681 | tty->termios.c_cc[VSTART] = tmp.t_startc; |
682 | tty->termios.c_cc[VSTOP] = tmp.t_stopc; |
683 | tty->termios.c_cc[VEOF] = tmp.t_eofc; |
684 | tty->termios.c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */ |
685 | up_write(&tty->termios_rwsem); |
686 | return 0; |
687 | } |
688 | #endif |
689 | |
690 | #ifdef TIOCGLTC |
691 | static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars) |
692 | { |
693 | struct ltchars tmp; |
694 | |
695 | down_read(&tty->termios_rwsem); |
696 | tmp.t_suspc = tty->termios.c_cc[VSUSP]; |
697 | /* what is dsuspc anyway? */ |
698 | tmp.t_dsuspc = tty->termios.c_cc[VSUSP]; |
699 | tmp.t_rprntc = tty->termios.c_cc[VREPRINT]; |
700 | /* what is flushc anyway? */ |
701 | tmp.t_flushc = tty->termios.c_cc[VEOL2]; |
702 | tmp.t_werasc = tty->termios.c_cc[VWERASE]; |
703 | tmp.t_lnextc = tty->termios.c_cc[VLNEXT]; |
704 | up_read(&tty->termios_rwsem); |
705 | return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0; |
706 | } |
707 | |
708 | static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars) |
709 | { |
710 | struct ltchars tmp; |
711 | |
712 | if (copy_from_user(&tmp, ltchars, sizeof(tmp))) |
713 | return -EFAULT; |
714 | |
715 | down_write(&tty->termios_rwsem); |
716 | tty->termios.c_cc[VSUSP] = tmp.t_suspc; |
717 | /* what is dsuspc anyway? */ |
718 | tty->termios.c_cc[VEOL2] = tmp.t_dsuspc; |
719 | tty->termios.c_cc[VREPRINT] = tmp.t_rprntc; |
720 | /* what is flushc anyway? */ |
721 | tty->termios.c_cc[VEOL2] = tmp.t_flushc; |
722 | tty->termios.c_cc[VWERASE] = tmp.t_werasc; |
723 | tty->termios.c_cc[VLNEXT] = tmp.t_lnextc; |
724 | up_write(&tty->termios_rwsem); |
725 | return 0; |
726 | } |
727 | #endif |
728 | |
729 | /** |
730 | * tty_change_softcar - carrier change ioctl helper |
731 | * @tty: tty to update |
732 | * @enable: enable/disable %CLOCAL |
733 | * |
734 | * Perform a change to the %CLOCAL state and call into the driver layer to make |
735 | * it visible. |
736 | * |
737 | * Locking: &tty_struct->termios_rwsem. |
738 | * |
739 | * Returns: 0 on success, an error otherwise |
740 | */ |
741 | static int tty_change_softcar(struct tty_struct *tty, bool enable) |
742 | { |
743 | int ret = 0; |
744 | struct ktermios old; |
745 | tcflag_t bit = enable ? CLOCAL : 0; |
746 | |
747 | down_write(sem: &tty->termios_rwsem); |
748 | old = tty->termios; |
749 | tty->termios.c_cflag &= ~CLOCAL; |
750 | tty->termios.c_cflag |= bit; |
751 | if (tty->ops->set_termios) |
752 | tty->ops->set_termios(tty, &old); |
753 | if (C_CLOCAL(tty) != bit) |
754 | ret = -EINVAL; |
755 | up_write(sem: &tty->termios_rwsem); |
756 | return ret; |
757 | } |
758 | |
759 | /** |
760 | * tty_mode_ioctl - mode related ioctls |
761 | * @tty: tty for the ioctl |
762 | * @cmd: command |
763 | * @arg: ioctl argument |
764 | * |
765 | * Perform non-line discipline specific mode control ioctls. This is designed |
766 | * to be called by line disciplines to ensure they provide consistent mode |
767 | * setting. |
768 | */ |
769 | int tty_mode_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg) |
770 | { |
771 | struct tty_struct *real_tty; |
772 | void __user *p = (void __user *)arg; |
773 | int ret = 0; |
774 | struct ktermios kterm; |
775 | |
776 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
777 | tty->driver->subtype == PTY_TYPE_MASTER) |
778 | real_tty = tty->link; |
779 | else |
780 | real_tty = tty; |
781 | |
782 | switch (cmd) { |
783 | #ifdef TIOCGETP |
784 | case TIOCGETP: |
785 | return get_sgttyb(real_tty, (struct sgttyb __user *) arg); |
786 | case TIOCSETP: |
787 | case TIOCSETN: |
788 | return set_sgttyb(real_tty, (struct sgttyb __user *) arg); |
789 | #endif |
790 | #ifdef TIOCGETC |
791 | case TIOCGETC: |
792 | return get_tchars(real_tty, p); |
793 | case TIOCSETC: |
794 | return set_tchars(real_tty, p); |
795 | #endif |
796 | #ifdef TIOCGLTC |
797 | case TIOCGLTC: |
798 | return get_ltchars(real_tty, p); |
799 | case TIOCSLTC: |
800 | return set_ltchars(real_tty, p); |
801 | #endif |
802 | case TCSETSF: |
803 | return set_termios(tty: real_tty, arg: p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD); |
804 | case TCSETSW: |
805 | return set_termios(tty: real_tty, arg: p, TERMIOS_WAIT | TERMIOS_OLD); |
806 | case TCSETS: |
807 | return set_termios(tty: real_tty, arg: p, TERMIOS_OLD); |
808 | #ifndef TCGETS2 |
809 | case TCGETS: |
810 | copy_termios(real_tty, &kterm); |
811 | if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm)) |
812 | ret = -EFAULT; |
813 | return ret; |
814 | #else |
815 | case TCGETS: |
816 | copy_termios(tty: real_tty, kterm: &kterm); |
817 | if (kernel_termios_to_user_termios_1(u: (struct termios __user *)arg, k: &kterm)) |
818 | ret = -EFAULT; |
819 | return ret; |
820 | case TCGETS2: |
821 | copy_termios(tty: real_tty, kterm: &kterm); |
822 | if (kernel_termios_to_user_termios(u: (struct termios2 __user *)arg, k: &kterm)) |
823 | ret = -EFAULT; |
824 | return ret; |
825 | case TCSETSF2: |
826 | return set_termios(tty: real_tty, arg: p, TERMIOS_FLUSH | TERMIOS_WAIT); |
827 | case TCSETSW2: |
828 | return set_termios(tty: real_tty, arg: p, TERMIOS_WAIT); |
829 | case TCSETS2: |
830 | return set_termios(tty: real_tty, arg: p, opt: 0); |
831 | #endif |
832 | case TCGETA: |
833 | return get_termio(tty: real_tty, termio: p); |
834 | case TCSETAF: |
835 | return set_termios(tty: real_tty, arg: p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO); |
836 | case TCSETAW: |
837 | return set_termios(tty: real_tty, arg: p, TERMIOS_WAIT | TERMIOS_TERMIO); |
838 | case TCSETA: |
839 | return set_termios(tty: real_tty, arg: p, TERMIOS_TERMIO); |
840 | #ifndef TCGETS2 |
841 | case TIOCGLCKTRMIOS: |
842 | copy_termios_locked(real_tty, &kterm); |
843 | if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm)) |
844 | ret = -EFAULT; |
845 | return ret; |
846 | case TIOCSLCKTRMIOS: |
847 | if (!capable(CAP_SYS_ADMIN)) |
848 | return -EPERM; |
849 | copy_termios_locked(real_tty, &kterm); |
850 | if (user_termios_to_kernel_termios(&kterm, |
851 | (struct termios __user *) arg)) |
852 | return -EFAULT; |
853 | down_write(&real_tty->termios_rwsem); |
854 | real_tty->termios_locked = kterm; |
855 | up_write(&real_tty->termios_rwsem); |
856 | return 0; |
857 | #else |
858 | case TIOCGLCKTRMIOS: |
859 | copy_termios_locked(tty: real_tty, kterm: &kterm); |
860 | if (kernel_termios_to_user_termios_1(u: (struct termios __user *)arg, k: &kterm)) |
861 | ret = -EFAULT; |
862 | return ret; |
863 | case TIOCSLCKTRMIOS: |
864 | if (!capable(CAP_SYS_ADMIN)) |
865 | return -EPERM; |
866 | copy_termios_locked(tty: real_tty, kterm: &kterm); |
867 | if (user_termios_to_kernel_termios_1(k: &kterm, |
868 | u: (struct termios __user *) arg)) |
869 | return -EFAULT; |
870 | down_write(sem: &real_tty->termios_rwsem); |
871 | real_tty->termios_locked = kterm; |
872 | up_write(sem: &real_tty->termios_rwsem); |
873 | return ret; |
874 | #endif |
875 | #ifdef TCGETX |
876 | case TCGETX: |
877 | case TCSETX: |
878 | case TCSETXW: |
879 | case TCSETXF: |
880 | return -ENOTTY; |
881 | #endif |
882 | case TIOCGSOFTCAR: |
883 | copy_termios(tty: real_tty, kterm: &kterm); |
884 | ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0, |
885 | (int __user *)arg); |
886 | return ret; |
887 | case TIOCSSOFTCAR: |
888 | if (get_user(arg, (unsigned int __user *) arg)) |
889 | return -EFAULT; |
890 | return tty_change_softcar(tty: real_tty, enable: arg); |
891 | default: |
892 | return -ENOIOCTLCMD; |
893 | } |
894 | } |
895 | EXPORT_SYMBOL_GPL(tty_mode_ioctl); |
896 | |
897 | |
898 | /* Caller guarantees ldisc reference is held */ |
899 | static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg) |
900 | { |
901 | struct tty_ldisc *ld = tty->ldisc; |
902 | |
903 | switch (arg) { |
904 | case TCIFLUSH: |
905 | if (ld && ld->ops->flush_buffer) { |
906 | ld->ops->flush_buffer(tty); |
907 | tty_unthrottle(tty); |
908 | } |
909 | break; |
910 | case TCIOFLUSH: |
911 | if (ld && ld->ops->flush_buffer) { |
912 | ld->ops->flush_buffer(tty); |
913 | tty_unthrottle(tty); |
914 | } |
915 | fallthrough; |
916 | case TCOFLUSH: |
917 | tty_driver_flush_buffer(tty); |
918 | break; |
919 | default: |
920 | return -EINVAL; |
921 | } |
922 | return 0; |
923 | } |
924 | |
925 | int tty_perform_flush(struct tty_struct *tty, unsigned long arg) |
926 | { |
927 | struct tty_ldisc *ld; |
928 | int retval = tty_check_change(tty); |
929 | if (retval) |
930 | return retval; |
931 | |
932 | ld = tty_ldisc_ref_wait(tty); |
933 | retval = __tty_perform_flush(tty, arg); |
934 | if (ld) |
935 | tty_ldisc_deref(ld); |
936 | return retval; |
937 | } |
938 | EXPORT_SYMBOL_GPL(tty_perform_flush); |
939 | |
940 | int n_tty_ioctl_helper(struct tty_struct *tty, unsigned int cmd, |
941 | unsigned long arg) |
942 | { |
943 | int retval; |
944 | |
945 | switch (cmd) { |
946 | case TCXONC: |
947 | retval = tty_check_change(tty); |
948 | if (retval) |
949 | return retval; |
950 | switch (arg) { |
951 | case TCOOFF: |
952 | spin_lock_irq(lock: &tty->flow.lock); |
953 | if (!tty->flow.tco_stopped) { |
954 | tty->flow.tco_stopped = true; |
955 | __stop_tty(tty); |
956 | } |
957 | spin_unlock_irq(lock: &tty->flow.lock); |
958 | break; |
959 | case TCOON: |
960 | spin_lock_irq(lock: &tty->flow.lock); |
961 | if (tty->flow.tco_stopped) { |
962 | tty->flow.tco_stopped = false; |
963 | __start_tty(tty); |
964 | } |
965 | spin_unlock_irq(lock: &tty->flow.lock); |
966 | break; |
967 | case TCIOFF: |
968 | if (STOP_CHAR(tty) != __DISABLED_CHAR) |
969 | retval = tty_send_xchar(tty, STOP_CHAR(tty)); |
970 | break; |
971 | case TCION: |
972 | if (START_CHAR(tty) != __DISABLED_CHAR) |
973 | retval = tty_send_xchar(tty, START_CHAR(tty)); |
974 | break; |
975 | default: |
976 | return -EINVAL; |
977 | } |
978 | return retval; |
979 | case TCFLSH: |
980 | retval = tty_check_change(tty); |
981 | if (retval) |
982 | return retval; |
983 | return __tty_perform_flush(tty, arg); |
984 | default: |
985 | /* Try the mode commands */ |
986 | return tty_mode_ioctl(tty, cmd, arg); |
987 | } |
988 | } |
989 | EXPORT_SYMBOL(n_tty_ioctl_helper); |
990 | |