drivers/tty/tty

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
tty_chars_in_buffer
tty_write_room
tty_driver_flush_buffer
tty_throttle
tty_unthrottle
tty_throttle_safe
tty_unthrottle_safe
tty_wait_until_sent
unset_locked_termios
tty_termios_copy_hw
tty_termios_hw_change
tty_set_termios
set_termios
copy_termios
copy_termios_locked
get_termio
set_termiox
get_sgflags
get_sgttyb
set_sgflags
set_sgttyb
get_tchars
set_tchars
get_ltchars
set_ltchars
tty_change_softcar
tty_mode_ioctl
__tty_perform_flush
tty_perform_flush
n_tty_ioctl_helper
   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         ld = tty_ldisc_ref(tty);
 401 
 402         if (ld != NULL) {
 403                 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
 404                         ld->ops->flush_buffer(tty);
 405                 tty_ldisc_deref(ld);
 406         }
 407 
 408         if (opt & TERMIOS_WAIT) {
 409                 tty_wait_until_sent(tty, 0);
 410                 if (signal_pending(current))
 411                         return -ERESTARTSYS;
 412         }
 413 
 414         tty_set_termios(tty, &tmp_termios);
 415 
 416         /* FIXME: Arguably if tmp_termios == tty->termios AND the
 417            actual requested termios was not tmp_termios then we may
 418            want to return an error as no user requested change has
 419            succeeded */
 420         return 0;
 421 }
 422 
 423 static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
 424 {
 425         down_read(&tty->termios_rwsem);
 426         *kterm = tty->termios;
 427         up_read(&tty->termios_rwsem);
 428 }
 429 
 430 static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
 431 {
 432         down_read(&tty->termios_rwsem);
 433         *kterm = tty->termios_locked;
 434         up_read(&tty->termios_rwsem);
 435 }
 436 
 437 static int get_termio(struct tty_struct *tty, struct termio __user *termio)
 438 {
 439         struct ktermios kterm;
 440         copy_termios(tty, &kterm);
 441         if (kernel_termios_to_user_termio(termio, &kterm))
 442                 return -EFAULT;
 443         return 0;
 444 }
 445 
 446 
 447 #ifdef TCGETX
 448 
 449 /**
 450  *      set_termiox     -       set termiox fields if possible
 451  *      @tty: terminal
 452  *      @arg: termiox structure from user
 453  *      @opt: option flags for ioctl type
 454  *
 455  *      Implement the device calling points for the SYS5 termiox ioctl
 456  *      interface in Linux
 457  */
 458 
 459 static int set_termiox(struct tty_struct *tty, void __user *arg, int opt)
 460 {
 461         struct termiox tnew;
 462         struct tty_ldisc *ld;
 463 
 464         if (tty->termiox == NULL)
 465                 return -EINVAL;
 466         if (copy_from_user(&tnew, arg, sizeof(struct termiox)))
 467                 return -EFAULT;
 468 
 469         ld = tty_ldisc_ref(tty);
 470         if (ld != NULL) {
 471                 if ((opt & TERMIOS_FLUSH) && ld->ops->flush_buffer)
 472                         ld->ops->flush_buffer(tty);
 473                 tty_ldisc_deref(ld);
 474         }
 475         if (opt & TERMIOS_WAIT) {
 476                 tty_wait_until_sent(tty, 0);
 477                 if (signal_pending(current))
 478                         return -ERESTARTSYS;
 479         }
 480 
 481         down_write(&tty->termios_rwsem);
 482         if (tty->ops->set_termiox)
 483                 tty->ops->set_termiox(tty, &tnew);
 484         up_write(&tty->termios_rwsem);
 485         return 0;
 486 }
 487 
 488 #endif
 489 
 490 
 491 #ifdef TIOCGETP
 492 /*
 493  * These are deprecated, but there is limited support..
 494  *
 495  * The "sg_flags" translation is a joke..
 496  */
 497 static int get_sgflags(struct tty_struct *tty)
 498 {
 499         int flags = 0;
 500 
 501         if (!L_ICANON(tty)) {
 502                 if (L_ISIG(tty))
 503                         flags |= 0x02;          /* cbreak */
 504                 else
 505                         flags |= 0x20;          /* raw */
 506         }
 507         if (L_ECHO(tty))
 508                 flags |= 0x08;                  /* echo */
 509         if (O_OPOST(tty))
 510                 if (O_ONLCR(tty))
 511                         flags |= 0x10;          /* crmod */
 512         return flags;
 513 }
 514 
 515 static int get_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
 516 {
 517         struct sgttyb tmp;
 518 
 519         down_read(&tty->termios_rwsem);
 520         tmp.sg_ispeed = tty->termios.c_ispeed;
 521         tmp.sg_ospeed = tty->termios.c_ospeed;
 522         tmp.sg_erase = tty->termios.c_cc[VERASE];
 523         tmp.sg_kill = tty->termios.c_cc[VKILL];
 524         tmp.sg_flags = get_sgflags(tty);
 525         up_read(&tty->termios_rwsem);
 526 
 527         return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 528 }
 529 
 530 static void set_sgflags(struct ktermios *termios, int flags)
 531 {
 532         termios->c_iflag = ICRNL | IXON;
 533         termios->c_oflag = 0;
 534         termios->c_lflag = ISIG | ICANON;
 535         if (flags & 0x02) {     /* cbreak */
 536                 termios->c_iflag = 0;
 537                 termios->c_lflag &= ~ICANON;
 538         }
 539         if (flags & 0x08) {             /* echo */
 540                 termios->c_lflag |= ECHO | ECHOE | ECHOK |
 541                                     ECHOCTL | ECHOKE | IEXTEN;
 542         }
 543         if (flags & 0x10) {             /* crmod */
 544                 termios->c_oflag |= OPOST | ONLCR;
 545         }
 546         if (flags & 0x20) {     /* raw */
 547                 termios->c_iflag = 0;
 548                 termios->c_lflag &= ~(ISIG | ICANON);
 549         }
 550         if (!(termios->c_lflag & ICANON)) {
 551                 termios->c_cc[VMIN] = 1;
 552                 termios->c_cc[VTIME] = 0;
 553         }
 554 }
 555 
 556 /**
 557  *      set_sgttyb              -       set legacy terminal values
 558  *      @tty: tty structure
 559  *      @sgttyb: pointer to old style terminal structure
 560  *
 561  *      Updates a terminal from the legacy BSD style terminal information
 562  *      structure.
 563  *
 564  *      Locking: termios_rwsem
 565  */
 566 
 567 static int set_sgttyb(struct tty_struct *tty, struct sgttyb __user *sgttyb)
 568 {
 569         int retval;
 570         struct sgttyb tmp;
 571         struct ktermios termios;
 572 
 573         retval = tty_check_change(tty);
 574         if (retval)
 575                 return retval;
 576 
 577         if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
 578                 return -EFAULT;
 579 
 580         down_write(&tty->termios_rwsem);
 581         termios = tty->termios;
 582         termios.c_cc[VERASE] = tmp.sg_erase;
 583         termios.c_cc[VKILL] = tmp.sg_kill;
 584         set_sgflags(&termios, tmp.sg_flags);
 585         /* Try and encode into Bfoo format */
 586 #ifdef BOTHER
 587         tty_termios_encode_baud_rate(&termios, termios.c_ispeed,
 588                                                 termios.c_ospeed);
 589 #endif
 590         up_write(&tty->termios_rwsem);
 591         tty_set_termios(tty, &termios);
 592         return 0;
 593 }
 594 #endif
 595 
 596 #ifdef TIOCGETC
 597 static int get_tchars(struct tty_struct *tty, struct tchars __user *tchars)
 598 {
 599         struct tchars tmp;
 600 
 601         down_read(&tty->termios_rwsem);
 602         tmp.t_intrc = tty->termios.c_cc[VINTR];
 603         tmp.t_quitc = tty->termios.c_cc[VQUIT];
 604         tmp.t_startc = tty->termios.c_cc[VSTART];
 605         tmp.t_stopc = tty->termios.c_cc[VSTOP];
 606         tmp.t_eofc = tty->termios.c_cc[VEOF];
 607         tmp.t_brkc = tty->termios.c_cc[VEOL2];  /* what is brkc anyway? */
 608         up_read(&tty->termios_rwsem);
 609         return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 610 }
 611 
 612 static int set_tchars(struct tty_struct *tty, struct tchars __user *tchars)
 613 {
 614         struct tchars tmp;
 615 
 616         if (copy_from_user(&tmp, tchars, sizeof(tmp)))
 617                 return -EFAULT;
 618         down_write(&tty->termios_rwsem);
 619         tty->termios.c_cc[VINTR] = tmp.t_intrc;
 620         tty->termios.c_cc[VQUIT] = tmp.t_quitc;
 621         tty->termios.c_cc[VSTART] = tmp.t_startc;
 622         tty->termios.c_cc[VSTOP] = tmp.t_stopc;
 623         tty->termios.c_cc[VEOF] = tmp.t_eofc;
 624         tty->termios.c_cc[VEOL2] = tmp.t_brkc;  /* what is brkc anyway? */
 625         up_write(&tty->termios_rwsem);
 626         return 0;
 627 }
 628 #endif
 629 
 630 #ifdef TIOCGLTC
 631 static int get_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
 632 {
 633         struct ltchars tmp;
 634 
 635         down_read(&tty->termios_rwsem);
 636         tmp.t_suspc = tty->termios.c_cc[VSUSP];
 637         /* what is dsuspc anyway? */
 638         tmp.t_dsuspc = tty->termios.c_cc[VSUSP];
 639         tmp.t_rprntc = tty->termios.c_cc[VREPRINT];
 640         /* what is flushc anyway? */
 641         tmp.t_flushc = tty->termios.c_cc[VEOL2];
 642         tmp.t_werasc = tty->termios.c_cc[VWERASE];
 643         tmp.t_lnextc = tty->termios.c_cc[VLNEXT];
 644         up_read(&tty->termios_rwsem);
 645         return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 646 }
 647 
 648 static int set_ltchars(struct tty_struct *tty, struct ltchars __user *ltchars)
 649 {
 650         struct ltchars tmp;
 651 
 652         if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
 653                 return -EFAULT;
 654 
 655         down_write(&tty->termios_rwsem);
 656         tty->termios.c_cc[VSUSP] = tmp.t_suspc;
 657         /* what is dsuspc anyway? */
 658         tty->termios.c_cc[VEOL2] = tmp.t_dsuspc;
 659         tty->termios.c_cc[VREPRINT] = tmp.t_rprntc;
 660         /* what is flushc anyway? */
 661         tty->termios.c_cc[VEOL2] = tmp.t_flushc;
 662         tty->termios.c_cc[VWERASE] = tmp.t_werasc;
 663         tty->termios.c_cc[VLNEXT] = tmp.t_lnextc;
 664         up_write(&tty->termios_rwsem);
 665         return 0;
 666 }
 667 #endif
 668 
 669 /**
 670  *      tty_change_softcar      -       carrier change ioctl helper
 671  *      @tty: tty to update
 672  *      @arg: enable/disable CLOCAL
 673  *
 674  *      Perform a change to the CLOCAL state and call into the driver
 675  *      layer to make it visible. All done with the termios rwsem
 676  */
 677 
 678 static int tty_change_softcar(struct tty_struct *tty, int arg)
 679 {
 680         int ret = 0;
 681         int bit = arg ? CLOCAL : 0;
 682         struct ktermios old;
 683 
 684         down_write(&tty->termios_rwsem);
 685         old = tty->termios;
 686         tty->termios.c_cflag &= ~CLOCAL;
 687         tty->termios.c_cflag |= bit;
 688         if (tty->ops->set_termios)
 689                 tty->ops->set_termios(tty, &old);
 690         if (C_CLOCAL(tty) != bit)
 691                 ret = -EINVAL;
 692         up_write(&tty->termios_rwsem);
 693         return ret;
 694 }
 695 
 696 /**
 697  *      tty_mode_ioctl          -       mode related ioctls
 698  *      @tty: tty for the ioctl
 699  *      @file: file pointer for the tty
 700  *      @cmd: command
 701  *      @arg: ioctl argument
 702  *
 703  *      Perform non line discipline specific mode control ioctls. This
 704  *      is designed to be called by line disciplines to ensure they provide
 705  *      consistent mode setting.
 706  */
 707 
 708 int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
 709                         unsigned int cmd, unsigned long arg)
 710 {
 711         struct tty_struct *real_tty;
 712         void __user *p = (void __user *)arg;
 713         int ret = 0;
 714         struct ktermios kterm;
 715 
 716         BUG_ON(file == NULL);
 717 
 718         if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 719             tty->driver->subtype == PTY_TYPE_MASTER)
 720                 real_tty = tty->link;
 721         else
 722                 real_tty = tty;
 723 
 724         switch (cmd) {
 725 #ifdef TIOCGETP
 726         case TIOCGETP:
 727                 return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
 728         case TIOCSETP:
 729         case TIOCSETN:
 730                 return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
 731 #endif
 732 #ifdef TIOCGETC
 733         case TIOCGETC:
 734                 return get_tchars(real_tty, p);
 735         case TIOCSETC:
 736                 return set_tchars(real_tty, p);
 737 #endif
 738 #ifdef TIOCGLTC
 739         case TIOCGLTC:
 740                 return get_ltchars(real_tty, p);
 741         case TIOCSLTC:
 742                 return set_ltchars(real_tty, p);
 743 #endif
 744         case TCSETSF:
 745                 return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_OLD);
 746         case TCSETSW:
 747                 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_OLD);
 748         case TCSETS:
 749                 return set_termios(real_tty, p, TERMIOS_OLD);
 750 #ifndef TCGETS2
 751         case TCGETS:
 752                 copy_termios(real_tty, &kterm);
 753                 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
 754                         ret = -EFAULT;
 755                 return ret;
 756 #else
 757         case TCGETS:
 758                 copy_termios(real_tty, &kterm);
 759                 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
 760                         ret = -EFAULT;
 761                 return ret;
 762         case TCGETS2:
 763                 copy_termios(real_tty, &kterm);
 764                 if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
 765                         ret = -EFAULT;
 766                 return ret;
 767         case TCSETSF2:
 768                 return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT);
 769         case TCSETSW2:
 770                 return set_termios(real_tty, p, TERMIOS_WAIT);
 771         case TCSETS2:
 772                 return set_termios(real_tty, p, 0);
 773 #endif
 774         case TCGETA:
 775                 return get_termio(real_tty, p);
 776         case TCSETAF:
 777                 return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
 778         case TCSETAW:
 779                 return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
 780         case TCSETA:
 781                 return set_termios(real_tty, p, TERMIOS_TERMIO);
 782 #ifndef TCGETS2
 783         case TIOCGLCKTRMIOS:
 784                 copy_termios_locked(real_tty, &kterm);
 785                 if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
 786                         ret = -EFAULT;
 787                 return ret;
 788         case TIOCSLCKTRMIOS:
 789                 if (!capable(CAP_SYS_ADMIN))
 790                         return -EPERM;
 791                 copy_termios_locked(real_tty, &kterm);
 792                 if (user_termios_to_kernel_termios(&kterm,
 793                                                (struct termios __user *) arg))
 794                         return -EFAULT;
 795                 down_write(&real_tty->termios_rwsem);
 796                 real_tty->termios_locked = kterm;
 797                 up_write(&real_tty->termios_rwsem);
 798                 return 0;
 799 #else
 800         case TIOCGLCKTRMIOS:
 801                 copy_termios_locked(real_tty, &kterm);
 802                 if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
 803                         ret = -EFAULT;
 804                 return ret;
 805         case TIOCSLCKTRMIOS:
 806                 if (!capable(CAP_SYS_ADMIN))
 807                         return -EPERM;
 808                 copy_termios_locked(real_tty, &kterm);
 809                 if (user_termios_to_kernel_termios_1(&kterm,
 810                                                (struct termios __user *) arg))
 811                         return -EFAULT;
 812                 down_write(&real_tty->termios_rwsem);
 813                 real_tty->termios_locked = kterm;
 814                 up_write(&real_tty->termios_rwsem);
 815                 return ret;
 816 #endif
 817 #ifdef TCGETX
 818         case TCGETX: {
 819                 struct termiox ktermx;
 820                 if (real_tty->termiox == NULL)
 821                         return -EINVAL;
 822                 down_read(&real_tty->termios_rwsem);
 823                 memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
 824                 up_read(&real_tty->termios_rwsem);
 825                 if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
 826                         ret = -EFAULT;
 827                 return ret;
 828         }
 829         case TCSETX:
 830                 return set_termiox(real_tty, p, 0);
 831         case TCSETXW:
 832                 return set_termiox(real_tty, p, TERMIOS_WAIT);
 833         case TCSETXF:
 834                 return set_termiox(real_tty, p, TERMIOS_FLUSH);
 835 #endif          
 836         case TIOCGSOFTCAR:
 837                 copy_termios(real_tty, &kterm);
 838                 ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
 839                                                 (int __user *)arg);
 840                 return ret;
 841         case TIOCSSOFTCAR:
 842                 if (get_user(arg, (unsigned int __user *) arg))
 843                         return -EFAULT;
 844                 return tty_change_softcar(real_tty, arg);
 845         default:
 846                 return -ENOIOCTLCMD;
 847         }
 848 }
 849 EXPORT_SYMBOL_GPL(tty_mode_ioctl);
 850 
 851 
 852 /* Caller guarantees ldisc reference is held */
 853 static int __tty_perform_flush(struct tty_struct *tty, unsigned long arg)
 854 {
 855         struct tty_ldisc *ld = tty->ldisc;
 856 
 857         switch (arg) {
 858         case TCIFLUSH:
 859                 if (ld && ld->ops->flush_buffer) {
 860                         ld->ops->flush_buffer(tty);
 861                         tty_unthrottle(tty);
 862                 }
 863                 break;
 864         case TCIOFLUSH:
 865                 if (ld && ld->ops->flush_buffer) {
 866                         ld->ops->flush_buffer(tty);
 867                         tty_unthrottle(tty);
 868                 }
 869                 /* fall through */
 870         case TCOFLUSH:
 871                 tty_driver_flush_buffer(tty);
 872                 break;
 873         default:
 874                 return -EINVAL;
 875         }
 876         return 0;
 877 }
 878 
 879 int tty_perform_flush(struct tty_struct *tty, unsigned long arg)
 880 {
 881         struct tty_ldisc *ld;
 882         int retval = tty_check_change(tty);
 883         if (retval)
 884                 return retval;
 885 
 886         ld = tty_ldisc_ref_wait(tty);
 887         retval = __tty_perform_flush(tty, arg);
 888         if (ld)
 889                 tty_ldisc_deref(ld);
 890         return retval;
 891 }
 892 EXPORT_SYMBOL_GPL(tty_perform_flush);
 893 
 894 int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
 895                        unsigned int cmd, unsigned long arg)
 896 {
 897         int retval;
 898 
 899         switch (cmd) {
 900         case TCXONC:
 901                 retval = tty_check_change(tty);
 902                 if (retval)
 903                         return retval;
 904                 switch (arg) {
 905                 case TCOOFF:
 906                         spin_lock_irq(&tty->flow_lock);
 907                         if (!tty->flow_stopped) {
 908                                 tty->flow_stopped = 1;
 909                                 __stop_tty(tty);
 910                         }
 911                         spin_unlock_irq(&tty->flow_lock);
 912                         break;
 913                 case TCOON:
 914                         spin_lock_irq(&tty->flow_lock);
 915                         if (tty->flow_stopped) {
 916                                 tty->flow_stopped = 0;
 917                                 __start_tty(tty);
 918                         }
 919                         spin_unlock_irq(&tty->flow_lock);
 920                         break;
 921                 case TCIOFF:
 922                         if (STOP_CHAR(tty) != __DISABLED_CHAR)
 923                                 retval = tty_send_xchar(tty, STOP_CHAR(tty));
 924                         break;
 925                 case TCION:
 926                         if (START_CHAR(tty) != __DISABLED_CHAR)
 927                                 retval = tty_send_xchar(tty, START_CHAR(tty));
 928                         break;
 929                 default:
 930                         return -EINVAL;
 931                 }
 932                 return retval;
 933         case TCFLSH:
 934                 retval = tty_check_change(tty);
 935                 if (retval)
 936                         return retval;
 937                 return __tty_perform_flush(tty, arg);
 938         default:
 939                 /* Try the mode commands */
 940                 return tty_mode_ioctl(tty, file, cmd, arg);
 941         }
 942 }
 943 EXPORT_SYMBOL(n_tty_ioctl_helper);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/tty/tty_ioctl.c

DEFINITIONS
