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
  23 #include <asm/io.h>
  24 #include <asm/bitops.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
 102         local_irq_disable(); // FIXME: is this safe?
 103         *tty->termios = *new_termios;
 104         unset_locked_termios(tty->termios, &old_termios, tty->termios_locked);
 105         canon_change = (old_termios.c_lflag ^ tty->termios->c_lflag) & ICANON;
 106         if (canon_change) {
 107                 memset(&tty->read_flags, 0, sizeof tty->read_flags);
 108                 tty->canon_head = tty->read_tail;
 109                 tty->canon_data = 0;
 110                 tty->erasing = 0;
 111         }
 112         local_irq_enable(); // FIXME: is this safe?
 113         if (canon_change && !L_ICANON(tty) && tty->read_cnt)
 114                 /* Get characters left over from canonical mode. */
 115                 wake_up_interruptible(&tty->read_wait);
 116
 117         /* see if packet mode change of state */
 118
 119         if (tty->link && tty->link->packet) {
 120                 int old_flow = ((old_termios.c_iflag & IXON) &&
 121                                 (old_termios.c_cc[VSTOP] == '\023') &&
 122                                 (old_termios.c_cc[VSTART] == '\021'));
 123                 int new_flow = (I_IXON(tty) &&
 124                                 STOP_CHAR(tty) == '\023' &&
 125                                 START_CHAR(tty) == '\021');
 126                 if (old_flow != new_flow) {
 127                         tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
 128                         if (new_flow)
 129                                 tty->ctrl_status |= TIOCPKT_DOSTOP;
 130                         else
 131                                 tty->ctrl_status |= TIOCPKT_NOSTOP;
 132                         wake_up_interruptible(&tty->link->read_wait);
 133                 }
 134         }
 135
 136         if (tty->driver->set_termios)
 137                 (*tty->driver->set_termios)(tty, &old_termios);
 138
 139         if (tty->ldisc.set_termios)
 140                 (*tty->ldisc.set_termios)(tty, &old_termios);
 141 }
 142
 143 static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
 144 {
 145         struct termios tmp_termios;
 146         int retval = tty_check_change(tty);
 147
 148         if (retval)
 149                 return retval;
 150
 151         if (opt & TERMIOS_TERMIO) {
 152                 memcpy(&tmp_termios, tty->termios, sizeof(struct termios));
 153                 if (user_termio_to_kernel_termios(&tmp_termios,
 154                                                 (struct termio __user *)arg))
 155                         return -EFAULT;
 156         } else {
 157                 if (user_termios_to_kernel_termios(&tmp_termios,
 158                                                 (struct termios __user *)arg))
 159                         return -EFAULT;
 160         }
 161
 162         if ((opt & TERMIOS_FLUSH) && tty->ldisc.flush_buffer)
 163                 tty->ldisc.flush_buffer(tty);
 164
 165         if (opt & TERMIOS_WAIT) {
 166                 tty_wait_until_sent(tty, 0);
 167                 if (signal_pending(current))
 168                         return -EINTR;
 169         }
 170
 171         change_termios(tty, &tmp_termios);
 172         return 0;
 173 }
 174
 175 static int get_termio(struct tty_struct * tty, struct termio __user * termio)
 176 {
 177         if (kernel_termios_to_user_termio(termio, tty->termios))
 178                 return -EFAULT;
 179         return 0;
 180 }
 181
 182 static unsigned long inq_canon(struct tty_struct * tty)
 183 {
 184         int nr, head, tail;
 185
 186         if (!tty->canon_data || !tty->read_buf)
 187                 return 0;
 188         head = tty->canon_head;
 189         tail = tty->read_tail;
 190         nr = (head - tail) & (N_TTY_BUF_SIZE-1);
 191         /* Skip EOF-chars.. */
 192         while (head != tail) {
 193                 if (test_bit(tail, tty->read_flags) &&
 194                     tty->read_buf[tail] == __DISABLED_CHAR)
 195                         nr--;
 196                 tail = (tail+1) & (N_TTY_BUF_SIZE-1);
 197         }
 198         return nr;
 199 }
 200
 201 #ifdef TIOCGETP
 202 /*
 203  * These are deprecated, but there is limited support..
 204  *
 205  * The "sg_flags" translation is a joke..
 206  */
 207 static int get_sgflags(struct tty_struct * tty)
 208 {
 209         int flags = 0;
 210
 211         if (!(tty->termios->c_lflag & ICANON)) {
 212                 if (tty->termios->c_lflag & ISIG)
 213                         flags |= 0x02;          /* cbreak */
 214                 else
 215                         flags |= 0x20;          /* raw */
 216         }
 217         if (tty->termios->c_lflag & ECHO)
 218                 flags |= 0x08;                  /* echo */
 219         if (tty->termios->c_oflag & OPOST)
 220                 if (tty->termios->c_oflag & ONLCR)
 221                         flags |= 0x10;          /* crmod */
 222         return flags;
 223 }
 224
 225 static int get_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 226 {
 227         struct sgttyb tmp;
 228
 229         tmp.sg_ispeed = 0;
 230         tmp.sg_ospeed = 0;
 231         tmp.sg_erase = tty->termios->c_cc[VERASE];
 232         tmp.sg_kill = tty->termios->c_cc[VKILL];
 233         tmp.sg_flags = get_sgflags(tty);
 234         return copy_to_user(sgttyb, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 235 }
 236
 237 static void set_sgflags(struct termios * termios, int flags)
 238 {
 239         termios->c_iflag = ICRNL | IXON;
 240         termios->c_oflag = 0;
 241         termios->c_lflag = ISIG | ICANON;
 242         if (flags & 0x02) {     /* cbreak */
 243                 termios->c_iflag = 0;
 244                 termios->c_lflag &= ~ICANON;
 245         }
 246         if (flags & 0x08) {             /* echo */
 247                 termios->c_lflag |= ECHO | ECHOE | ECHOK |
 248                                     ECHOCTL | ECHOKE | IEXTEN;
 249         }
 250         if (flags & 0x10) {             /* crmod */
 251                 termios->c_oflag |= OPOST | ONLCR;
 252         }
 253         if (flags & 0x20) {     /* raw */
 254                 termios->c_iflag = 0;
 255                 termios->c_lflag &= ~(ISIG | ICANON);
 256         }
 257         if (!(termios->c_lflag & ICANON)) {
 258                 termios->c_cc[VMIN] = 1;
 259                 termios->c_cc[VTIME] = 0;
 260         }
 261 }
 262
 263 static int set_sgttyb(struct tty_struct * tty, struct sgttyb __user * sgttyb)
 264 {
 265         int retval;
 266         struct sgttyb tmp;
 267         struct termios termios;
 268
 269         retval = tty_check_change(tty);
 270         if (retval)
 271                 return retval;
 272         termios =  *tty->termios;
 273         if (copy_from_user(&tmp, sgttyb, sizeof(tmp)))
 274                 return -EFAULT;
 275         termios.c_cc[VERASE] = tmp.sg_erase;
 276         termios.c_cc[VKILL] = tmp.sg_kill;
 277         set_sgflags(&termios, tmp.sg_flags);
 278         change_termios(tty, &termios);
 279         return 0;
 280 }
 281 #endif
 282
 283 #ifdef TIOCGETC
 284 static int get_tchars(struct tty_struct * tty, struct tchars __user * tchars)
 285 {
 286         struct tchars tmp;
 287
 288         tmp.t_intrc = tty->termios->c_cc[VINTR];
 289         tmp.t_quitc = tty->termios->c_cc[VQUIT];
 290         tmp.t_startc = tty->termios->c_cc[VSTART];
 291         tmp.t_stopc = tty->termios->c_cc[VSTOP];
 292         tmp.t_eofc = tty->termios->c_cc[VEOF];
 293         tmp.t_brkc = tty->termios->c_cc[VEOL2]; /* what is brkc anyway? */
 294         return copy_to_user(tchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 295 }
 296
 297 static int set_tchars(struct tty_struct * tty, struct tchars __user * tchars)
 298 {
 299         struct tchars tmp;
 300
 301         if (copy_from_user(&tmp, tchars, sizeof(tmp)))
 302                 return -EFAULT;
 303         tty->termios->c_cc[VINTR] = tmp.t_intrc;
 304         tty->termios->c_cc[VQUIT] = tmp.t_quitc;
 305         tty->termios->c_cc[VSTART] = tmp.t_startc;
 306         tty->termios->c_cc[VSTOP] = tmp.t_stopc;
 307         tty->termios->c_cc[VEOF] = tmp.t_eofc;
 308         tty->termios->c_cc[VEOL2] = tmp.t_brkc; /* what is brkc anyway? */
 309         return 0;
 310 }
 311 #endif
 312
 313 #ifdef TIOCGLTC
 314 static int get_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars)
 315 {
 316         struct ltchars tmp;
 317
 318         tmp.t_suspc = tty->termios->c_cc[VSUSP];
 319         tmp.t_dsuspc = tty->termios->c_cc[VSUSP];       /* what is dsuspc anyway? */
 320         tmp.t_rprntc = tty->termios->c_cc[VREPRINT];
 321         tmp.t_flushc = tty->termios->c_cc[VEOL2];       /* what is flushc anyway? */
 322         tmp.t_werasc = tty->termios->c_cc[VWERASE];
 323         tmp.t_lnextc = tty->termios->c_cc[VLNEXT];
 324         return copy_to_user(ltchars, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 325 }
 326
 327 static int set_ltchars(struct tty_struct * tty, struct ltchars __user * ltchars)
 328 {
 329         struct ltchars tmp;
 330
 331         if (copy_from_user(&tmp, ltchars, sizeof(tmp)))
 332                 return -EFAULT;
 333
 334         tty->termios->c_cc[VSUSP] = tmp.t_suspc;
 335         tty->termios->c_cc[VEOL2] = tmp.t_dsuspc;       /* what is dsuspc anyway? */
 336         tty->termios->c_cc[VREPRINT] = tmp.t_rprntc;
 337         tty->termios->c_cc[VEOL2] = tmp.t_flushc;       /* what is flushc anyway? */
 338         tty->termios->c_cc[VWERASE] = tmp.t_werasc;
 339         tty->termios->c_cc[VLNEXT] = tmp.t_lnextc;
 340         return 0;
 341 }
 342 #endif
 343
 344 /*
 345  * Send a high priority character to the tty.
 346  */
 347 void send_prio_char(struct tty_struct *tty, char ch)
 348 {
 349         int     was_stopped = tty->stopped;
 350
 351         if (tty->driver->send_xchar) {
 352                 tty->driver->send_xchar(tty, ch);
 353                 return;
 354         }
 355         if (was_stopped)
 356                 start_tty(tty);
 357         tty->driver->write(tty, 0, &ch, 1);
 358         if (was_stopped)
 359                 stop_tty(tty);
 360 }
 361
 362 int n_tty_ioctl(struct tty_struct * tty, struct file * file,
 363                        unsigned int cmd, unsigned long arg)
 364 {
 365         struct tty_struct * real_tty;
 366         void __user *p = (void __user *)arg;
 367         int retval;
 368
 369         if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
 370             tty->driver->subtype == PTY_TYPE_MASTER)
 371                 real_tty = tty->link;
 372         else
 373                 real_tty = tty;
 374
 375         switch (cmd) {
 376 #ifdef TIOCGETP
 377                 case TIOCGETP:
 378                         return get_sgttyb(real_tty, (struct sgttyb __user *) arg);
 379                 case TIOCSETP:
 380                 case TIOCSETN:
 381                         return set_sgttyb(real_tty, (struct sgttyb __user *) arg);
 382 #endif
 383 #ifdef TIOCGETC
 384                 case TIOCGETC:
 385                         return get_tchars(real_tty, p);
 386                 case TIOCSETC:
 387                         return set_tchars(real_tty, p);
 388 #endif
 389 #ifdef TIOCGLTC
 390                 case TIOCGLTC:
 391                         return get_ltchars(real_tty, p);
 392                 case TIOCSLTC:
 393                         return set_ltchars(real_tty, p);
 394 #endif
 395                 case TCGETS:
 396                         if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
 397                                 return -EFAULT;
 398                         return 0;
 399                 case TCSETSF:
 400                         return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT);
 401                 case TCSETSW:
 402                         return set_termios(real_tty, p, TERMIOS_WAIT);
 403                 case TCSETS:
 404                         return set_termios(real_tty, p, 0);
 405                 case TCGETA:
 406                         return get_termio(real_tty, p);
 407                 case TCSETAF:
 408                         return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT | TERMIOS_TERMIO);
 409                 case TCSETAW:
 410                         return set_termios(real_tty, p, TERMIOS_WAIT | TERMIOS_TERMIO);
 411                 case TCSETA:
 412                         return set_termios(real_tty, p, TERMIOS_TERMIO);
 413                 case TCXONC:
 414                         retval = tty_check_change(tty);
 415                         if (retval)
 416                                 return retval;
 417                         switch (arg) {
 418                         case TCOOFF:
 419                                 if (!tty->flow_stopped) {
 420                                         tty->flow_stopped = 1;
 421                                         stop_tty(tty);
 422                                 }
 423                                 break;
 424                         case TCOON:
 425                                 if (tty->flow_stopped) {
 426                                         tty->flow_stopped = 0;
 427                                         start_tty(tty);
 428                                 }
 429                                 break;
 430                         case TCIOFF:
 431                                 if (STOP_CHAR(tty) != __DISABLED_CHAR)
 432                                         send_prio_char(tty, STOP_CHAR(tty));
 433                                 break;
 434                         case TCION:
 435                                 if (START_CHAR(tty) != __DISABLED_CHAR)
 436                                         send_prio_char(tty, START_CHAR(tty));
 437                                 break;
 438                         default:
 439                                 return -EINVAL;
 440                         }
 441                         return 0;
 442                 case TCFLSH:
 443                         retval = tty_check_change(tty);
 444                         if (retval)
 445                                 return retval;
 446                         switch (arg) {
 447                         case TCIFLUSH:
 448                                 if (tty->ldisc.flush_buffer)
 449                                         tty->ldisc.flush_buffer(tty);
 450                                 break;
 451                         case TCIOFLUSH:
 452                                 if (tty->ldisc.flush_buffer)
 453                                         tty->ldisc.flush_buffer(tty);
 454                                 /* fall through */
 455                         case TCOFLUSH:
 456                                 if (tty->driver->flush_buffer)
 457                                         tty->driver->flush_buffer(tty);
 458                                 break;
 459                         default:
 460                                 return -EINVAL;
 461                         }
 462                         return 0;
 463                 case TIOCOUTQ:
 464                         return put_user(tty->driver->chars_in_buffer ?
 465                                         tty->driver->chars_in_buffer(tty) : 0,
 466                                         (int __user *) arg);
 467                 case TIOCINQ:
 468                         retval = tty->read_cnt;
 469                         if (L_ICANON(tty))
 470                                 retval = inq_canon(tty);
 471                         return put_user(retval, (unsigned int __user *) arg);
 472                 case TIOCGLCKTRMIOS:
 473                         if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
 474                                 return -EFAULT;
 475                         return 0;
 476
 477                 case TIOCSLCKTRMIOS:
 478                         if (!capable(CAP_SYS_ADMIN))
 479                                 return -EPERM;
 480                         if (user_termios_to_kernel_termios(real_tty->termios_locked, (struct termios __user *) arg))
 481                                 return -EFAULT;
 482                         return 0;
 483
 484                 case TIOCPKT:
 485                 {
 486                         int pktmode;
 487
 488                         if (tty->driver->type != TTY_DRIVER_TYPE_PTY ||
 489                             tty->driver->subtype != PTY_TYPE_MASTER)
 490                                 return -ENOTTY;
 491                         if (get_user(pktmode, (int __user *) arg))
 492                                 return -EFAULT;
 493                         if (pktmode) {
 494                                 if (!tty->packet) {
 495                                         tty->packet = 1;
 496                                         tty->link->ctrl_status = 0;
 497                                 }
 498                         } else
 499                                 tty->packet = 0;
 500                         return 0;
 501                 }
 502                 case TIOCGSOFTCAR:
 503                         return put_user(C_CLOCAL(tty) ? 1 : 0, (int __user *)arg);
 504                 case TIOCSSOFTCAR:
 505                         if (get_user(arg, (unsigned int __user *) arg))
 506                                 return -EFAULT;
 507                         tty->termios->c_cflag =
 508                                 ((tty->termios->c_cflag & ~CLOCAL) |
 509                                  (arg ? CLOCAL : 0));
 510                         return 0;
 511                 default:
 512                         return -ENOIOCTLCMD;
 513                 }
 514 }
 515
 516 EXPORT_SYMBOL(n_tty_ioctl);