drivers/tty/tty_ioctl.c

   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
  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
  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  */
  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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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  */
 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
 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
 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
 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
 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
 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
 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
 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
 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
 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 */
 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
 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
 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
 966 #ifdef CONFIG_COMPAT
 967 long n_tty_compat_ioctl_helper(struct tty_struct *tty, struct file *file,
 968                                         unsigned int cmd, unsigned long arg)
 969 {
 970         switch (cmd) {
 971         case TIOCGLCKTRMIOS:
 972         case TIOCSLCKTRMIOS:
 973                 return tty_mode_ioctl(tty, file, cmd, (unsigned long) compat_ptr(arg));
 974         default:
 975                 return -ENOIOCTLCMD;
 976         }
 977 }
 978 EXPORT_SYMBOL(n_tty_compat_ioctl_helper);
 979 #endif
 980