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