drivers/char/tty_ioctl.c

   1 /*
   2  *  linux/drivers/char/tty_ioctl.c
   3  *
   4  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   5  *
   6  * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
   7  * which can be dynamically activated and de-activated by the line
   8  * discipline handling modules (like SLIP).
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/termios.h>
  13 #include <linux/errno.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/major.h>
  17 #include <linux/tty.h>
  18 #include <linux/fcntl.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/module.h>
  22 #include <linux/bitops.h>
  23
  24 #include <asm/io.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/system.h>
  27
  28 #undef TTY_DEBUG_WAIT_UNTIL_SENT
  29
  30 #undef  DEBUG
  31
  32 /*
  33  * Internal flag options for termios setting behavior
  34  */
  35 #define TERMIOS_FLUSH   1
  36 #define TERMIOS_WAIT    2
  37 #define TERMIOS_TERMIO  4
  38
  39 void tty_wait_until_sent(struct tty_struct * tty, long timeout)
  40 {
  41         DECLARE_WAITQUEUE(wait, current);
  42
  43 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
  44         char buf[64];
  45
  46         printk(KERN_DEBUG "%s wait until sent...\n", tty_name(tty, buf));
  47 #endif
  48         if (!tty->driver->chars_in_buffer)
  49                 return;
  50         add_wait_queue(&tty->write_wait, &wait);
  51         if (!timeout)
  52                 timeout = MAX_SCHEDULE_TIMEOUT;
  53         do {
  54 #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
  55                 printk(KERN_DEBUG "waiting %s...(%d)\n", tty_name(tty, buf),
  56                        tty->driver->chars_in_buffer(tty));
  57 #endif
  58                 set_current_state(TASK_INTERRUPTIBLE);
  59                 if (signal_pending(current))
  60                         goto stop_waiting;
  61                 if (!tty->driver->chars_in_buffer(tty))
  62                         break;
  63                 timeout = schedule_timeout(timeout);
  64         } while (timeout);
  65         if (tty->driver->wait_until_sent)
  66                 tty->driver->wait_until_sent(tty, timeout);
  67 stop_waiting:
  68         set_current_state(TASK_RUNNING);
  69         remove_wait_queue(&tty->write_wait, &wait);
  70 }
  71
  72 EXPORT_SYMBOL(tty_wait_until_sent);
  73
  74 static void unset_locked_termios(struct termios *termios,
  75                                  struct termios *old,
  76                                  struct termios *locked)
  77 {
  78         int     i;
  79
  80 #define NOSET_MASK(x,y,z) (x = ((x) & ~(z)) | ((y) & (z)))
  81
  82         if (!locked) {
  83                 printk(KERN_WARNING "Warning?!? termios_locked is NULL.\n");
  84                 return;
  85         }
  86
  87         NOSET_MASK(termios->c_iflag, old->c_iflag, locked->c_iflag);
  88         NOSET_MASK(termios->c_oflag, old->c_oflag, locked->c_oflag);
  89         NOSET_MASK(termios->c_cflag, old->c_cflag, locked->c_cflag);
  90         NOSET_MASK(termios->c_lflag, old->c_lflag, locked->c_lflag);
  91         termios->c_line = locked->c_line ? old->c_line : termios->c_line;
  92         for (i=0; i < NCCS; i++)
  93                 termios->c_cc[i] = locked->c_cc[i] ?
  94                         old->c_cc[i] : termios->c_cc[i];
  95 }
  96
  97 static void change_termios(struct tty_struct * tty, struct termios * new_termios)
  98 {
  99         int canon_change;
 100         struct termios old_termios = *tty->termios;
 101         struct tty_ldisc *ld;
 102
 103         /*
 104          *      Perform the actual termios internal changes under lock.
 105          */
 106
 107
 108         /* FIXME: we need to decide on some locking/ordering semantics
 109            for the set_termios notification eventually */
 110         down(&tty->termios_sem);
 111
 112         *tty->termios = *new_termios;
 113         unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
 114         canon_change = (old_termios.c_lflag ^ tty->termios->c_lflag) & ICANON;
 115         if (canon_change) {
 116                 memset(&tty->read_flags, 0, sizeof tty->read_flags);
 117                 tty->canon_head = tty->read_tail;
 118                 tty->canon_data = 0;
 119                 tty->erasing = 0;
 120         }
 121
 122
 123         if (canon_change && !L_ICANON(tty) && tty->read_cnt)
 124                 /* Get characters left over from canonical mode. */
 125                 wake_up_interruptible(&tty->read_wait);
 126
 127         /* See if packet mode change of state. */
 128
 129         if (tty->link && tty->link->packet) {
 130                 int old_flow = ((old_termios.c_iflag & IXON) &&
 131                                 (old_termios.c_cc[VSTOP] == '\023') &&
 132                                 (old_termios.c_cc[VSTART] == '\021'));
 133                 int new_flow = (I_IXON(tty) &&
 134                                 STOP_CHAR(tty) == '\023' &&
 135                                 START_CHAR(tty) == '\021');
 136                 if (old_flow != new_flow) {
 137                         tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
 138                         if (new_flow)
 139                                 tty->ctrl_status |= TIOCPKT_DOSTOP;
 140                         else
 141                                 tty->ctrl_status |= TIOCPKT_NOSTOP;
 142                         wake_up_interruptible(&tty->link->read_wait);
 143                 }
 144         }
 145
 146         if (tty->driver->set_termios)
 147                 (*tty->driver->set_termios)(tty, &old_termios);
 148
 149         ld = tty_ldisc_ref(tty);
 150         if (ld != NULL) {
 151                 if (ld->set_termios)
 152                         (ld->set_termios)(tty, &old_termios);
 153                 tty_ldisc_deref(ld);
 154         }
 155         up(&tty->termios_sem);
 156 }
 157
 158 static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
 159 {
 160         struct termios tmp_termios;
 161         struct tty_ldisc *ld;
 162         int retval = tty_check_change(tty);
 163
 164         if (retval)
 165                 return retval;
 166
 167         if (opt & TERMIOS_TERMIO) {
 168                 memcpy(&tmp_termios, tty->termios, sizeof(struct termios));
 169                 if (user_termio_to_kernel_termios(&tmp_termios,
 170                                                 (struct termio __user *)arg))
 171                         return -EFAULT;
 172         } else {
 173                 if (user_termios_to_kernel_termios(&tmp_termios,
 174                                                 (struct termios __user *)arg))
 175                         return -EFAULT;
 176         }
 177
 178         ld = tty_ldisc_ref(tty);
 179
 180         if (ld != NULL) {
 181                 if ((opt & TERMIOS_FLUSH) && ld->flush_buffer)
 182                         ld->flush_buffer(tty);
 183                 tty_ldisc_deref(ld);
 184         }
 185
 186         if (opt & TERMIOS_WAIT) {
 187                 tty_wait_until_sent(tty, 0);
 188                 if (signal_pending(current))
 189                         return -EINTR;
 190         }
 191
 192         change_termios(tty, &tmp_termios);
 193         return 0;
 194 }
 195
 196 static int get_termio(struct tty_struct * tty, struct termio __user * termio)
 197 {
 198         if (kernel_termios_to_user_termio(termio, tty->termios))
 199                 return -EFAULT;
 200         return 0;
 201 }
 202
 203 static unsigned long inq_canon(struct tty_struct * tty)
 204 {
 205         int nr, head, tail;
 206
 207         if (!tty->canon_data || !tty->read_buf)
 208                 return 0;
 209         head = tty->canon_head;
 210         tail = tty->read_tail;
 211         nr = (head - tail) & (N_TTY_BUF_SIZE-1);
 212         /* Skip EOF-chars.. */
 213         while (head != tail) {
 214                 if (test_bit(tail, tty->read_flags) &&
 215                     tty->read_buf[tail] == __DISABLED_CHAR)
 216                         nr--;
 217                 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
 218         }
 219         return nr;
 220 }
 221
 222 #ifdef TIOCGETP
 223 /*
 224  * These are deprecated, but there is limited support..
 225  *
 226  * The "sg_flags" translation is a joke..
 227  */
 228 static int get_sgflags(struct tty_struct * tty)
 229 {
 230         int flags = 0;
 231
 232         if (!(tty->termios->c_lflag & ICANON)) {
 233                 if (tty->termios->c_lflag & ISIG)
 234                         flags |= 0x02;          /* cbreak */
 235                 else
 236                         flags |= 0x20;          /* raw */
 237         }
 238         if (tty->termios->c_lflag & ECHO)
 239                 flags |= 0x08;                  /* echo */
 240         if (tty->termios->c_oflag & OPOST)
 241                 if (tty->termios->c_oflag & ONLCR)
 242                         flags |= 0x10;          /* crmod */
 243         return flags;
 244 }
 245
 246 static int get_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 247 {
 248         struct sgttyb tmp;
 249
 250         down(&tty->termios_sem);
 251         tmp.sg_ispeed = 0;
 252         tmp.sg_ospeed = 0;
 253         tmp.sg_erase = tty->termios->c_cc[VERASE];
 254         tmp.sg_kill = tty->termios->c_cc[VKILL];
 255         tmp.sg_flags = get_sgflags(tty);
 256         up(&tty->termios_sem);
 257
 258         return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 259 }
 260
 261 static void set_sgflags(struct termios * termios, int flags)
 262 {
 263         termios->c_iflag = ICRNL | IXON;
 264         termios->c_oflag = 0;
 265         termios->c_lflag = ISIG | ICANON;
 266         if (flags & 0x02) {     /* cbreak */
 267                 termios->c_iflag = 0;
 268                 termios->c_lflag &= ~ICANON;
 269         }
 270         if (flags & 0x08) {             /* echo */
 271                 termios->c_lflag |= ECHO | ECHOE | ECHOK |
 272                                     ECHOCTL | ECHOKE | IEXTEN;
 273         }
 274         if (flags & 0x10) {             /* crmod */
 275                 termios->c_oflag |= OPOST | ONLCR;
 276         }
 277         if (flags & 0x20) {     /* raw */
 278                 termios->c_iflag = 0;
 279                 termios->c_lflag &= ~(ISIG | ICANON);
 280         }
 281         if (!(termios->c_lflag & ICANON)) {
 282                 termios->c_cc[VMIN] = 1;
 283                 termios->c_cc[VTIME] = 0;
 284         }
 285 }
 286
 287 static int set_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 288 {
 289         int retval;
 290         struct sgttyb tmp;
 291         struct termios termios;
 292
 293         retval = tty_check_change(tty);
 294         if (retval)
 295                 return retval;
 296
 297         if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
 298                 return -EFAULT;
 299
 300         down(&tty->termios_sem);
 301         termios =  *tty->termios;
 302         termios.c_cc[VERASE] = tmp.sg_erase;
 303         termios.c_cc[VKILL] = tmp.sg_kill;
 304         set_sgflags(&termios, tmp.sg_flags);
 305         up(&tty->termios_sem);
 306         change_termios(tty, &termios);
 307         return 0;
 308 }
 309 #endif
 310
 311 #ifdef TIOCGETC
 312 static int get_tchars(struct tty_struct * tty, struct tchars __user * tchars)
 313 {
 314         struct tchars tmp;
 315
 316         tmp.t_intrc = tty->termios->c_cc[VINTR];
 317         tmp.t_quitc = tty->termios->c_cc[VQUIT];
 318         tmp.t_startc = tty->termios->c_cc[VSTART];
 319         tmp.t_stopc = tty->termios->c_cc[VSTOP];
 320         tmp.t_eofc = tty->termios->c_cc[VEOF];
 321         tmp.t_brkc = tty->termios->c_cc[VEOL2]; /* what is brkc anyway? */
 322         return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 323 }
 324
 325 static int set_tchars(struct tty_struct * tty, struct tchars __user * tchars)
 326 {
 327         struct tchars tmp;
 328
 329         if (copy_from_user(&tmp, tchars, sizeof(tmp)))
 330                 return -EFAULT;
 331         tty->termios->c_cc[VINTR] = tmp.t_intrc;
 332         tty->termios->c_cc[VQUIT] = tmp.t_quitc;
 333         tty->termios->c_cc[VSTART] = tmp.t_startc;
 334         tty->termios->c_cc[VSTOP] = tmp.t_stopc;
 335         tty->termios->c_cc[VEOF] = tmp.t_eofc;
 336         tty->termios->c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
 337         return 0;
 338 }
 339 #endif
 340
 341 #ifdef TIOCGLTC
 342 static int get_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars)
 343 {
 344         struct ltchars tmp;
 345
 346         tmp.t_suspc = tty->termios->c_cc[VSUSP];
 347         tmp.t_dsuspc = tty->termios->c_cc[VSUSP];       /* what is dsuspc anyway? */
 348         tmp.t_rprntc = tty->termios->c_cc[VREPRINT];
 349         tmp.t_flushc = tty->termios->c_cc[VEOL2];       /* what is flushc anyway? */
 350         tmp.t_werasc = tty->termios->c_cc[VWERASE];
 351         tmp.t_lnextc = tty->termios->c_cc[VLNEXT];
 352         return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 353 }
 354
 355 static int set_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars)
 356 {
 357         struct ltchars tmp;
 358
 359         if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
 360                 return -EFAULT;
 361
 362         tty->termios->c_cc[VSUSP] = tmp.t_suspc;
 363         tty->termios->c_cc[VEOL2] = tmp.t_dsuspc;       /* what is dsuspc anyway? */
 364         tty->termios->c_cc[VREPRINT] = tmp.t_rprntc;
 365         tty->termios->c_cc[VEOL2] = tmp.t_flushc;       /* what is flushc anyway? */
 366         tty->termios->c_cc[VWERASE] = tmp.t_werasc;
 367         tty->termios->c_cc[VLNEXT] = tmp.t_lnextc;
 368         return 0;
 369 }
 370 #endif
 371
 372 /*
 373  * Send a high priority character to the tty.
 374  */
 375 static void send_prio_char(struct tty_struct *tty, char ch)
 376 {
 377         int     was_stopped = tty->stopped;
 378
 379         if (tty->driver->send_xchar) {
 380                 tty->driver->send_xchar(tty, ch);
 381                 return;
 382         }
 383         if (was_stopped)
 384                 start_tty(tty);
 385         tty->driver->write(tty, &ch, 1);
 386         if (was_stopped)
 387                 stop_tty(tty);
 388 }
 389
 390 int n_tty_ioctl(struct tty_struct * tty, struct file * file,
 391                        unsigned int cmd, unsigned long arg)
 392 {
 393         struct tty_struct * real_tty;
 394         void __user *p = (void __user *)arg;
 395         int retval;
 396         struct tty_ldisc *ld;
 397
 398         if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 399             tty->driver->subtype == PTY_TYPE_MASTER)
 400                 real_tty = tty->link;
 401         else
 402                 real_tty = tty;
 403
 404         switch (cmd) {
 405 #ifdef TIOCGETP
 406                 case TIOCGETP:
 407                         return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
 408                 case TIOCSETP:
 409                 case TIOCSETN:
 410                         return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
 411 #endif
 412 #ifdef TIOCGETC
 413                 case TIOCGETC:
 414                         return get_tchars(real_tty, p);
 415                 case TIOCSETC:
 416                         return set_tchars(real_tty, p);
 417 #endif
 418 #ifdef TIOCGLTC
 419                 case TIOCGLTC:
 420                         return get_ltchars(real_tty, p);
 421                 case TIOCSLTC:
 422                         return set_ltchars(real_tty, p);
 423 #endif
 424                 case TCGETS:
 425                         if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
 426                                 return -EFAULT;
 427                         return 0;
 428                 case TCSETSF:
 429                         return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT);
 430                 case TCSETSW:
 431                         return set_termios(real_tty, p, TERMIOS_WAIT);
 432                 case TCSETS:
 433                         return set_termios(real_tty, p, 0);
 434                 case TCGETA:
 435                         return get_termio(real_tty, p);
 436                 case TCSETAF:
 437                         return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
 438                 case TCSETAW:
 439                         return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
 440                 case TCSETA:
 441                         return set_termios(real_tty, p, TERMIOS_TERMIO);
 442                 case TCXONC:
 443                         retval = tty_check_change(tty);
 444                         if (retval)
 445                                 return retval;
 446                         switch (arg) {
 447                         case TCOOFF:
 448                                 if (!tty->flow_stopped) {
 449                                         tty->flow_stopped = 1;
 450                                         stop_tty(tty);
 451                                 }
 452                                 break;
 453                         case TCOON:
 454                                 if (tty->flow_stopped) {
 455                                         tty->flow_stopped = 0;
 456                                         start_tty(tty);
 457                                 }
 458                                 break;
 459                         case TCIOFF:
 460                                 if (STOP_CHAR(tty) != __DISABLED_CHAR)
 461                                         send_prio_char(tty, STOP_CHAR(tty));
 462                                 break;
 463                         case TCION:
 464                                 if (START_CHAR(tty) != __DISABLED_CHAR)
 465                                         send_prio_char(tty, START_CHAR(tty));
 466                                 break;
 467                         default:
 468                                 return -EINVAL;
 469                         }
 470                         return 0;
 471                 case TCFLSH:
 472                         retval = tty_check_change(tty);
 473                         if (retval)
 474                                 return retval;
 475
 476                         ld = tty_ldisc_ref(tty);
 477                         switch (arg) {
 478                         case TCIFLUSH:
 479                                 if (ld->flush_buffer)
 480                                         ld->flush_buffer(tty);
 481                                 break;
 482                         case TCIOFLUSH:
 483                                 if (ld->flush_buffer)
 484                                         ld->flush_buffer(tty);
 485                                 /* fall through */
 486                         case TCOFLUSH:
 487                                 if (tty->driver->flush_buffer)
 488                                         tty->driver->flush_buffer(tty);
 489                                 break;
 490                         default:
 491                                 tty_ldisc_deref(ld);
 492                                 return -EINVAL;
 493                         }
 494                         tty_ldisc_deref(ld);
 495                         return 0;
 496                 case TIOCOUTQ:
 497                         return put_user(tty->driver->chars_in_buffer ?
 498                                         tty->driver->chars_in_buffer(tty) : 0,
 499                                         (int __user *) arg);
 500                 case TIOCINQ:
 501                         retval = tty->read_cnt;
 502                         if (L_ICANON(tty))
 503                                 retval = inq_canon(tty);
 504                         return put_user(retval, (unsigned int __user *) arg);
 505                 case TIOCGLCKTRMIOS:
 506                         if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
 507                                 return -EFAULT;
 508                         return 0;
 509
 510                 case TIOCSLCKTRMIOS:
 511                         if (!capable(CAP_SYS_ADMIN))
 512                                 return -EPERM;
 513                         if (user_termios_to_kernel_termios(real_tty->termios_locked, (struct termios __user *) arg))
 514                                 return -EFAULT;
 515                         return 0;
 516
 517                 case TIOCPKT:
 518                 {
 519                         int pktmode;
 520
 521                         if (tty->driver->type != TTY_DRIVER_TYPE_PTY ||
 522                             tty->driver->subtype != PTY_TYPE_MASTER)
 523                                 return -ENOTTY;
 524                         if (get_user(pktmode, (int __user *) arg))
 525                                 return -EFAULT;
 526                         if (pktmode) {
 527                                 if (!tty->packet) {
 528                                         tty->packet = 1;
 529                                         tty->link->ctrl_status = 0;
 530                                 }
 531                         } else
 532                                 tty->packet = 0;
 533                         return 0;
 534                 }
 535                 case TIOCGSOFTCAR:
 536                         return put_user(C_CLOCAL(tty) ? 1 : 0, (int __user *)arg);
 537                 case TIOCSSOFTCAR:
 538                         if (get_user(arg, (unsigned int __user *) arg))
 539                                 return -EFAULT;
 540                         down(&tty->termios_sem);
 541                         tty->termios->c_cflag =
 542                                 ((tty->termios->c_cflag & ~CLOCAL) |
 543                                  (arg ? CLOCAL : 0));
 544                         up(&tty->termios_sem);
 545                         return 0;
 546                 default:
 547                         return -ENOIOCTLCMD;
 548                 }
 549 }
 550
 551 EXPORT_SYMBOL(n_tty_ioctl);