drivers/tty/vt/vt_ioctl.c

   1 /*
   2  *  Copyright (C) 1992 obz under the linux copyright
   3  *
   4  *  Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
   5  *  Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
   6  *  Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
   7  *  Some code moved for less code duplication - Andi Kleen - Mar 1997
   8  *  Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/sched.h>
  14 #include <linux/tty.h>
  15 #include <linux/timer.h>
  16 #include <linux/kernel.h>
  17 #include <linux/compat.h>
  18 #include <linux/module.h>
  19 #include <linux/kd.h>
  20 #include <linux/vt.h>
  21 #include <linux/string.h>
  22 #include <linux/slab.h>
  23 #include <linux/major.h>
  24 #include <linux/fs.h>
  25 #include <linux/console.h>
  26 #include <linux/consolemap.h>
  27 #include <linux/signal.h>
  28 #include <linux/timex.h>
  29
  30 #include <asm/io.h>
  31 #include <asm/uaccess.h>
  32
  33 #include <linux/kbd_kern.h>
  34 #include <linux/vt_kern.h>
  35 #include <linux/kbd_diacr.h>
  36 #include <linux/selection.h>
  37
  38 char vt_dont_switch;
  39 extern struct tty_driver *console_driver;
  40
  41 #define VT_IS_IN_USE(i) (console_driver->ttys[i] && console_driver->ttys[i]->count)
  42 #define VT_BUSY(i)      (VT_IS_IN_USE(i) || i == fg_console || vc_cons[i].d == sel_cons)
  43
  44 /*
  45  * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
  46  * experimentation and study of X386 SYSV handling.
  47  *
  48  * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
  49  * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
  50  * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
  51  * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
  52  * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
  53  * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
  54  * to the current console is done by the main ioctl code.
  55  */
  56
  57 #ifdef CONFIG_X86
  58 #include <linux/syscalls.h>
  59 #endif
  60
  61 static void complete_change_console(struct vc_data *vc);
  62
  63 /*
  64  *      User space VT_EVENT handlers
  65  */
  66
  67 struct vt_event_wait {
  68         struct list_head list;
  69         struct vt_event event;
  70         int done;
  71 };
  72
  73 static LIST_HEAD(vt_events);
  74 static DEFINE_SPINLOCK(vt_event_lock);
  75 static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
  76
  77 /**
  78  *      vt_event_post
  79  *      @event: the event that occurred
  80  *      @old: old console
  81  *      @new: new console
  82  *
  83  *      Post an VT event to interested VT handlers
  84  */
  85
  86 void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
  87 {
  88         struct list_head *pos, *head;
  89         unsigned long flags;
  90         int wake = 0;
  91
  92         spin_lock_irqsave(&vt_event_lock, flags);
  93         head = &vt_events;
  94
  95         list_for_each(pos, head) {
  96                 struct vt_event_wait *ve = list_entry(pos,
  97                                                 struct vt_event_wait, list);
  98                 if (!(ve->event.event & event))
  99                         continue;
 100                 ve->event.event = event;
 101                 /* kernel view is consoles 0..n-1, user space view is
 102                    console 1..n with 0 meaning current, so we must bias */
 103                 ve->event.oldev = old + 1;
 104                 ve->event.newev = new + 1;
 105                 wake = 1;
 106                 ve->done = 1;
 107         }
 108         spin_unlock_irqrestore(&vt_event_lock, flags);
 109         if (wake)
 110                 wake_up_interruptible(&vt_event_waitqueue);
 111 }
 112
 113 /**
 114  *      vt_event_wait           -       wait for an event
 115  *      @vw: our event
 116  *
 117  *      Waits for an event to occur which completes our vt_event_wait
 118  *      structure. On return the structure has wv->done set to 1 for success
 119  *      or 0 if some event such as a signal ended the wait.
 120  */
 121
 122 static void vt_event_wait(struct vt_event_wait *vw)
 123 {
 124         unsigned long flags;
 125         /* Prepare the event */
 126         INIT_LIST_HEAD(&vw->list);
 127         vw->done = 0;
 128         /* Queue our event */
 129         spin_lock_irqsave(&vt_event_lock, flags);
 130         list_add(&vw->list, &vt_events);
 131         spin_unlock_irqrestore(&vt_event_lock, flags);
 132         /* Wait for it to pass */
 133         wait_event_interruptible(vt_event_waitqueue, vw->done);
 134         /* Dequeue it */
 135         spin_lock_irqsave(&vt_event_lock, flags);
 136         list_del(&vw->list);
 137         spin_unlock_irqrestore(&vt_event_lock, flags);
 138 }
 139
 140 /**
 141  *      vt_event_wait_ioctl     -       event ioctl handler
 142  *      @arg: argument to ioctl
 143  *
 144  *      Implement the VT_WAITEVENT ioctl using the VT event interface
 145  */
 146
 147 static int vt_event_wait_ioctl(struct vt_event __user *event)
 148 {
 149         struct vt_event_wait vw;
 150
 151         if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
 152                 return -EFAULT;
 153         /* Highest supported event for now */
 154         if (vw.event.event & ~VT_MAX_EVENT)
 155                 return -EINVAL;
 156
 157         vt_event_wait(&vw);
 158         /* If it occurred report it */
 159         if (vw.done) {
 160                 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
 161                         return -EFAULT;
 162                 return 0;
 163         }
 164         return -EINTR;
 165 }
 166
 167 /**
 168  *      vt_waitactive   -       active console wait
 169  *      @event: event code
 170  *      @n: new console
 171  *
 172  *      Helper for event waits. Used to implement the legacy
 173  *      event waiting ioctls in terms of events
 174  */
 175
 176 int vt_waitactive(int n)
 177 {
 178         struct vt_event_wait vw;
 179         do {
 180                 if (n == fg_console + 1)
 181                         break;
 182                 vw.event.event = VT_EVENT_SWITCH;
 183                 vt_event_wait(&vw);
 184                 if (vw.done == 0)
 185                         return -EINTR;
 186         } while (vw.event.newev != n);
 187         return 0;
 188 }
 189
 190 /*
 191  * these are the valid i/o ports we're allowed to change. they map all the
 192  * video ports
 193  */
 194 #define GPFIRST 0x3b4
 195 #define GPLAST 0x3df
 196 #define GPNUM (GPLAST - GPFIRST + 1)
 197
 198
 199
 200 static inline int
 201 do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
 202 {
 203         struct consolefontdesc cfdarg;
 204         int i;
 205
 206         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
 207                 return -EFAULT;
 208
 209         switch (cmd) {
 210         case PIO_FONTX:
 211                 if (!perm)
 212                         return -EPERM;
 213                 op->op = KD_FONT_OP_SET;
 214                 op->flags = KD_FONT_FLAG_OLD;
 215                 op->width = 8;
 216                 op->height = cfdarg.charheight;
 217                 op->charcount = cfdarg.charcount;
 218                 op->data = cfdarg.chardata;
 219                 return con_font_op(vc_cons[fg_console].d, op);
 220         case GIO_FONTX: {
 221                 op->op = KD_FONT_OP_GET;
 222                 op->flags = KD_FONT_FLAG_OLD;
 223                 op->width = 8;
 224                 op->height = cfdarg.charheight;
 225                 op->charcount = cfdarg.charcount;
 226                 op->data = cfdarg.chardata;
 227                 i = con_font_op(vc_cons[fg_console].d, op);
 228                 if (i)
 229                         return i;
 230                 cfdarg.charheight = op->height;
 231                 cfdarg.charcount = op->charcount;
 232                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
 233                         return -EFAULT;
 234                 return 0;
 235                 }
 236         }
 237         return -EINVAL;
 238 }
 239
 240 static inline int
 241 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
 242 {
 243         struct unimapdesc tmp;
 244
 245         if (copy_from_user(&tmp, user_ud, sizeof tmp))
 246                 return -EFAULT;
 247         if (tmp.entries)
 248                 if (!access_ok(VERIFY_WRITE, tmp.entries,
 249                                 tmp.entry_ct*sizeof(struct unipair)))
 250                         return -EFAULT;
 251         switch (cmd) {
 252         case PIO_UNIMAP:
 253                 if (!perm)
 254                         return -EPERM;
 255                 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
 256         case GIO_UNIMAP:
 257                 if (!perm && fg_console != vc->vc_num)
 258                         return -EPERM;
 259                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
 260         }
 261         return 0;
 262 }
 263
 264
 265
 266 /*
 267  * We handle the console-specific ioctl's here.  We allow the
 268  * capability to modify any console, not just the fg_console.
 269  */
 270 int vt_ioctl(struct tty_struct *tty,
 271              unsigned int cmd, unsigned long arg)
 272 {
 273         struct vc_data *vc = tty->driver_data;
 274         struct console_font_op op;      /* used in multiple places here */
 275         unsigned int console;
 276         unsigned char ucval;
 277         unsigned int uival;
 278         void __user *up = (void __user *)arg;
 279         int i, perm;
 280         int ret = 0;
 281
 282         console = vc->vc_num;
 283
 284
 285         if (!vc_cons_allocated(console)) {      /* impossible? */
 286                 ret = -ENOIOCTLCMD;
 287                 goto out;
 288         }
 289
 290
 291         /*
 292          * To have permissions to do most of the vt ioctls, we either have
 293          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
 294          */
 295         perm = 0;
 296         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
 297                 perm = 1;
 298
 299         switch (cmd) {
 300         case TIOCLINUX:
 301                 ret = tioclinux(tty, arg);
 302                 break;
 303         case KIOCSOUND:
 304                 if (!perm)
 305                         return -EPERM;
 306                 /*
 307                  * The use of PIT_TICK_RATE is historic, it used to be
 308                  * the platform-dependent CLOCK_TICK_RATE between 2.6.12
 309                  * and 2.6.36, which was a minor but unfortunate ABI
 310                  * change. kd_mksound is locked by the input layer.
 311                  */
 312                 if (arg)
 313                         arg = PIT_TICK_RATE / arg;
 314                 kd_mksound(arg, 0);
 315                 break;
 316
 317         case KDMKTONE:
 318                 if (!perm)
 319                         return -EPERM;
 320         {
 321                 unsigned int ticks, count;
 322
 323                 /*
 324                  * Generate the tone for the appropriate number of ticks.
 325                  * If the time is zero, turn off sound ourselves.
 326                  */
 327                 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
 328                 count = ticks ? (arg & 0xffff) : 0;
 329                 if (count)
 330                         count = PIT_TICK_RATE / count;
 331                 kd_mksound(count, ticks);
 332                 break;
 333         }
 334
 335         case KDGKBTYPE:
 336                 /*
 337                  * this is naïve.
 338                  */
 339                 ucval = KB_101;
 340                 ret = put_user(ucval, (char __user *)arg);
 341                 break;
 342
 343                 /*
 344                  * These cannot be implemented on any machine that implements
 345                  * ioperm() in user level (such as Alpha PCs) or not at all.
 346                  *
 347                  * XXX: you should never use these, just call ioperm directly..
 348                  */
 349 #ifdef CONFIG_X86
 350         case KDADDIO:
 351         case KDDELIO:
 352                 /*
 353                  * KDADDIO and KDDELIO may be able to add ports beyond what
 354                  * we reject here, but to be safe...
 355                  *
 356                  * These are locked internally via sys_ioperm
 357                  */
 358                 if (arg < GPFIRST || arg > GPLAST) {
 359                         ret = -EINVAL;
 360                         break;
 361                 }
 362                 ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 363                 break;
 364
 365         case KDENABIO:
 366         case KDDISABIO:
 367                 ret = sys_ioperm(GPFIRST, GPNUM,
 368                                   (cmd == KDENABIO)) ? -ENXIO : 0;
 369                 break;
 370 #endif
 371
 372         /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
 373
 374         case KDKBDREP:
 375         {
 376                 struct kbd_repeat kbrep;
 377
 378                 if (!capable(CAP_SYS_TTY_CONFIG))
 379                         return -EPERM;
 380
 381                 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
 382                         ret =  -EFAULT;
 383                         break;
 384                 }
 385                 ret = kbd_rate(&kbrep);
 386                 if (ret)
 387                         break;
 388                 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
 389                         ret = -EFAULT;
 390                 break;
 391         }
 392
 393         case KDSETMODE:
 394                 /*
 395                  * currently, setting the mode from KD_TEXT to KD_GRAPHICS
 396                  * doesn't do a whole lot. i'm not sure if it should do any
 397                  * restoration of modes or what...
 398                  *
 399                  * XXX It should at least call into the driver, fbdev's definitely
 400                  * need to restore their engine state. --BenH
 401                  */
 402                 if (!perm)
 403                         return -EPERM;
 404                 switch (arg) {
 405                 case KD_GRAPHICS:
 406                         break;
 407                 case KD_TEXT0:
 408                 case KD_TEXT1:
 409                         arg = KD_TEXT;
 410                 case KD_TEXT:
 411                         break;
 412                 default:
 413                         ret = -EINVAL;
 414                         goto out;
 415                 }
 416                 /* FIXME: this needs the console lock extending */
 417                 if (vc->vc_mode == (unsigned char) arg)
 418                         break;
 419                 vc->vc_mode = (unsigned char) arg;
 420                 if (console != fg_console)
 421                         break;
 422                 /*
 423                  * explicitly blank/unblank the screen if switching modes
 424                  */
 425                 console_lock();
 426                 if (arg == KD_TEXT)
 427                         do_unblank_screen(1);
 428                 else
 429                         do_blank_screen(1);
 430                 console_unlock();
 431                 break;
 432
 433         case KDGETMODE:
 434                 uival = vc->vc_mode;
 435                 goto setint;
 436
 437         case KDMAPDISP:
 438         case KDUNMAPDISP:
 439                 /*
 440                  * these work like a combination of mmap and KDENABIO.
 441                  * this could be easily finished.
 442                  */
 443                 ret = -EINVAL;
 444                 break;
 445
 446         case KDSKBMODE:
 447                 if (!perm)
 448                         return -EPERM;
 449                 ret = vt_do_kdskbmode(console, arg);
 450                 if (ret == 0)
 451                         tty_ldisc_flush(tty);
 452                 break;
 453
 454         case KDGKBMODE:
 455                 uival = vt_do_kdgkbmode(console);
 456                 ret = put_user(uival, (int __user *)arg);
 457                 break;
 458
 459         /* this could be folded into KDSKBMODE, but for compatibility
 460            reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 461         case KDSKBMETA:
 462                 ret = vt_do_kdskbmeta(console, arg);
 463                 break;
 464
 465         case KDGKBMETA:
 466                 /* FIXME: should review whether this is worth locking */
 467                 uival = vt_do_kdgkbmeta(console);
 468         setint:
 469                 ret = put_user(uival, (int __user *)arg);
 470                 break;
 471
 472         case KDGETKEYCODE:
 473         case KDSETKEYCODE:
 474                 if(!capable(CAP_SYS_TTY_CONFIG))
 475                         perm = 0;
 476                 ret = vt_do_kbkeycode_ioctl(cmd, up, perm);
 477                 break;
 478
 479         case KDGKBENT:
 480         case KDSKBENT:
 481                 ret = vt_do_kdsk_ioctl(cmd, up, perm, console);
 482                 break;
 483
 484         case KDGKBSENT:
 485         case KDSKBSENT:
 486                 ret = vt_do_kdgkb_ioctl(cmd, up, perm);
 487                 break;
 488
 489         /* Diacritical processing. Handled in keyboard.c as it has
 490            to operate on the keyboard locks and structures */
 491         case KDGKBDIACR:
 492         case KDGKBDIACRUC:
 493         case KDSKBDIACR:
 494         case KDSKBDIACRUC:
 495                 ret = vt_do_diacrit(cmd, up, perm);
 496                 break;
 497
 498         /* the ioctls below read/set the flags usually shown in the leds */
 499         /* don't use them - they will go away without warning */
 500         case KDGKBLED:
 501         case KDSKBLED:
 502         case KDGETLED:
 503         case KDSETLED:
 504                 ret = vt_do_kdskled(console, cmd, arg, perm);
 505                 break;
 506
 507         /*
 508          * A process can indicate its willingness to accept signals
 509          * generated by pressing an appropriate key combination.
 510          * Thus, one can have a daemon that e.g. spawns a new console
 511          * upon a keypress and then changes to it.
 512          * See also the kbrequest field of inittab(5).
 513          */
 514         case KDSIGACCEPT:
 515         {
 516                 if (!perm || !capable(CAP_KILL))
 517                         return -EPERM;
 518                 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
 519                         ret = -EINVAL;
 520                 else {
 521                         spin_lock_irq(&vt_spawn_con.lock);
 522                         put_pid(vt_spawn_con.pid);
 523                         vt_spawn_con.pid = get_pid(task_pid(current));
 524                         vt_spawn_con.sig = arg;
 525                         spin_unlock_irq(&vt_spawn_con.lock);
 526                 }
 527                 break;
 528         }
 529
 530         case VT_SETMODE:
 531         {
 532                 struct vt_mode tmp;
 533
 534                 if (!perm)
 535                         return -EPERM;
 536                 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
 537                         ret = -EFAULT;
 538                         goto out;
 539                 }
 540                 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
 541                         ret = -EINVAL;
 542                         goto out;
 543                 }
 544                 console_lock();
 545                 vc->vt_mode = tmp;
 546                 /* the frsig is ignored, so we set it to 0 */
 547                 vc->vt_mode.frsig = 0;
 548                 put_pid(vc->vt_pid);
 549                 vc->vt_pid = get_pid(task_pid(current));
 550                 /* no switch is required -- saw@shade.msu.ru */
 551                 vc->vt_newvt = -1;
 552                 console_unlock();
 553                 break;
 554         }
 555
 556         case VT_GETMODE:
 557         {
 558                 struct vt_mode tmp;
 559                 int rc;
 560
 561                 console_lock();
 562                 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
 563                 console_unlock();
 564
 565                 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
 566                 if (rc)
 567                         ret = -EFAULT;
 568                 break;
 569         }
 570
 571         /*
 572          * Returns global vt state. Note that VT 0 is always open, since
 573          * it's an alias for the current VT, and people can't use it here.
 574          * We cannot return state for more than 16 VTs, since v_state is short.
 575          */
 576         case VT_GETSTATE:
 577         {
 578                 struct vt_stat __user *vtstat = up;
 579                 unsigned short state, mask;
 580
 581                 /* Review: FIXME: Console lock ? */
 582                 if (put_user(fg_console + 1, &vtstat->v_active))
 583                         ret = -EFAULT;
 584                 else {
 585                         state = 1;      /* /dev/tty0 is always open */
 586                         for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
 587                                                         ++i, mask <<= 1)
 588                                 if (VT_IS_IN_USE(i))
 589                                         state |= mask;
 590                         ret = put_user(state, &vtstat->v_state);
 591                 }
 592                 break;
 593         }
 594
 595         /*
 596          * Returns the first available (non-opened) console.
 597          */
 598         case VT_OPENQRY:
 599                 /* FIXME: locking ? - but then this is a stupid API */
 600                 for (i = 0; i < MAX_NR_CONSOLES; ++i)
 601                         if (! VT_IS_IN_USE(i))
 602                                 break;
 603                 uival = i < MAX_NR_CONSOLES ? (i+1) : -1;
 604                 goto setint;
 605
 606         /*
 607          * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
 608          * with num >= 1 (switches to vt 0, our console, are not allowed, just
 609          * to preserve sanity).
 610          */
 611         case VT_ACTIVATE:
 612                 if (!perm)
 613                         return -EPERM;
 614                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 615                         ret =  -ENXIO;
 616                 else {
 617                         arg--;
 618                         console_lock();
 619                         ret = vc_allocate(arg);
 620                         console_unlock();
 621                         if (ret)
 622                                 break;
 623                         set_console(arg);
 624                 }
 625                 break;
 626
 627         case VT_SETACTIVATE:
 628         {
 629                 struct vt_setactivate vsa;
 630
 631                 if (!perm)
 632                         return -EPERM;
 633
 634                 if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,
 635                                         sizeof(struct vt_setactivate))) {
 636                         ret = -EFAULT;
 637                         goto out;
 638                 }
 639                 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
 640                         ret = -ENXIO;
 641                 else {
 642                         vsa.console--;
 643                         console_lock();
 644                         ret = vc_allocate(vsa.console);
 645                         if (ret == 0) {
 646                                 struct vc_data *nvc;
 647                                 /* This is safe providing we don't drop the
 648                                    console sem between vc_allocate and
 649                                    finishing referencing nvc */
 650                                 nvc = vc_cons[vsa.console].d;
 651                                 nvc->vt_mode = vsa.mode;
 652                                 nvc->vt_mode.frsig = 0;
 653                                 put_pid(nvc->vt_pid);
 654                                 nvc->vt_pid = get_pid(task_pid(current));
 655                         }
 656                         console_unlock();
 657                         if (ret)
 658                                 break;
 659                         /* Commence switch and lock */
 660                         /* Review set_console locks */
 661                         set_console(vsa.console);
 662                 }
 663                 break;
 664         }
 665
 666         /*
 667          * wait until the specified VT has been activated
 668          */
 669         case VT_WAITACTIVE:
 670                 if (!perm)
 671                         return -EPERM;
 672                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 673                         ret = -ENXIO;
 674                 else
 675                         ret = vt_waitactive(arg);
 676                 break;
 677
 678         /*
 679          * If a vt is under process control, the kernel will not switch to it
 680          * immediately, but postpone the operation until the process calls this
 681          * ioctl, allowing the switch to complete.
 682          *
 683          * According to the X sources this is the behavior:
 684          *      0:      pending switch-from not OK
 685          *      1:      pending switch-from OK
 686          *      2:      completed switch-to OK
 687          */
 688         case VT_RELDISP:
 689                 if (!perm)
 690                         return -EPERM;
 691
 692                 console_lock();
 693                 if (vc->vt_mode.mode != VT_PROCESS) {
 694                         console_unlock();
 695                         ret = -EINVAL;
 696                         break;
 697                 }
 698                 /*
 699                  * Switching-from response
 700                  */
 701                 if (vc->vt_newvt >= 0) {
 702                         if (arg == 0)
 703                                 /*
 704                                  * Switch disallowed, so forget we were trying
 705                                  * to do it.
 706                                  */
 707                                 vc->vt_newvt = -1;
 708
 709                         else {
 710                                 /*
 711                                  * The current vt has been released, so
 712                                  * complete the switch.
 713                                  */
 714                                 int newvt;
 715                                 newvt = vc->vt_newvt;
 716                                 vc->vt_newvt = -1;
 717                                 ret = vc_allocate(newvt);
 718                                 if (ret) {
 719                                         console_unlock();
 720                                         break;
 721                                 }
 722                                 /*
 723                                  * When we actually do the console switch,
 724                                  * make sure we are atomic with respect to
 725                                  * other console switches..
 726                                  */
 727                                 complete_change_console(vc_cons[newvt].d);
 728                         }
 729                 } else {
 730                         /*
 731                          * Switched-to response
 732                          */
 733                         /*
 734                          * If it's just an ACK, ignore it
 735                          */
 736                         if (arg != VT_ACKACQ)
 737                                 ret = -EINVAL;
 738                 }
 739                 console_unlock();
 740                 break;
 741
 742          /*
 743           * Disallocate memory associated to VT (but leave VT1)
 744           */
 745          case VT_DISALLOCATE:
 746                 if (arg > MAX_NR_CONSOLES) {
 747                         ret = -ENXIO;
 748                         break;
 749                 }
 750                 if (arg == 0) {
 751                     /* deallocate all unused consoles, but leave 0 */
 752                         console_lock();
 753                         for (i=1; i<MAX_NR_CONSOLES; i++)
 754                                 if (! VT_BUSY(i))
 755                                         vc_deallocate(i);
 756                         console_unlock();
 757                 } else {
 758                         /* deallocate a single console, if possible */
 759                         arg--;
 760                         if (VT_BUSY(arg))
 761                                 ret = -EBUSY;
 762                         else if (arg) {                       /* leave 0 */
 763                                 console_lock();
 764                                 vc_deallocate(arg);
 765                                 console_unlock();
 766                         }
 767                 }
 768                 break;
 769
 770         case VT_RESIZE:
 771         {
 772                 struct vt_sizes __user *vtsizes = up;
 773                 struct vc_data *vc;
 774
 775                 ushort ll,cc;
 776                 if (!perm)
 777                         return -EPERM;
 778                 if (get_user(ll, &vtsizes->v_rows) ||
 779                     get_user(cc, &vtsizes->v_cols))
 780                         ret = -EFAULT;
 781                 else {
 782                         console_lock();
 783                         for (i = 0; i < MAX_NR_CONSOLES; i++) {
 784                                 vc = vc_cons[i].d;
 785
 786                                 if (vc) {
 787                                         vc->vc_resize_user = 1;
 788                                         /* FIXME: review v tty lock */
 789                                         vc_resize(vc_cons[i].d, cc, ll);
 790                                 }
 791                         }
 792                         console_unlock();
 793                 }
 794                 break;
 795         }
 796
 797         case VT_RESIZEX:
 798         {
 799                 struct vt_consize __user *vtconsize = up;
 800                 ushort ll,cc,vlin,clin,vcol,ccol;
 801                 if (!perm)
 802                         return -EPERM;
 803                 if (!access_ok(VERIFY_READ, vtconsize,
 804                                 sizeof(struct vt_consize))) {
 805                         ret = -EFAULT;
 806                         break;
 807                 }
 808                 /* FIXME: Should check the copies properly */
 809                 __get_user(ll, &vtconsize->v_rows);
 810                 __get_user(cc, &vtconsize->v_cols);
 811                 __get_user(vlin, &vtconsize->v_vlin);
 812                 __get_user(clin, &vtconsize->v_clin);
 813                 __get_user(vcol, &vtconsize->v_vcol);
 814                 __get_user(ccol, &vtconsize->v_ccol);
 815                 vlin = vlin ? vlin : vc->vc_scan_lines;
 816                 if (clin) {
 817                         if (ll) {
 818                                 if (ll != vlin/clin) {
 819                                         /* Parameters don't add up */
 820                                         ret = -EINVAL;
 821                                         break;
 822                                 }
 823                         } else
 824                                 ll = vlin/clin;
 825                 }
 826                 if (vcol && ccol) {
 827                         if (cc) {
 828                                 if (cc != vcol/ccol) {
 829                                         ret = -EINVAL;
 830                                         break;
 831                                 }
 832                         } else
 833                                 cc = vcol/ccol;
 834                 }
 835
 836                 if (clin > 32) {
 837                         ret =  -EINVAL;
 838                         break;
 839                 }
 840
 841                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 842                         if (!vc_cons[i].d)
 843                                 continue;
 844                         console_lock();
 845                         if (vlin)
 846                                 vc_cons[i].d->vc_scan_lines = vlin;
 847                         if (clin)
 848                                 vc_cons[i].d->vc_font.height = clin;
 849                         vc_cons[i].d->vc_resize_user = 1;
 850                         vc_resize(vc_cons[i].d, cc, ll);
 851                         console_unlock();
 852                 }
 853                 break;
 854         }
 855
 856         case PIO_FONT: {
 857                 if (!perm)
 858                         return -EPERM;
 859                 op.op = KD_FONT_OP_SET;
 860                 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
 861                 op.width = 8;
 862                 op.height = 0;
 863                 op.charcount = 256;
 864                 op.data = up;
 865                 ret = con_font_op(vc_cons[fg_console].d, &op);
 866                 break;
 867         }
 868
 869         case GIO_FONT: {
 870                 op.op = KD_FONT_OP_GET;
 871                 op.flags = KD_FONT_FLAG_OLD;
 872                 op.width = 8;
 873                 op.height = 32;
 874                 op.charcount = 256;
 875                 op.data = up;
 876                 ret = con_font_op(vc_cons[fg_console].d, &op);
 877                 break;
 878         }
 879
 880         case PIO_CMAP:
 881                 if (!perm)
 882                         ret = -EPERM;
 883                 else
 884                         ret = con_set_cmap(up);
 885                 break;
 886
 887         case GIO_CMAP:
 888                 ret = con_get_cmap(up);
 889                 break;
 890
 891         case PIO_FONTX:
 892         case GIO_FONTX:
 893                 ret = do_fontx_ioctl(cmd, up, perm, &op);
 894                 break;
 895
 896         case PIO_FONTRESET:
 897         {
 898                 if (!perm)
 899                         return -EPERM;
 900
 901 #ifdef BROKEN_GRAPHICS_PROGRAMS
 902                 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
 903                    font is not saved. */
 904                 ret = -ENOSYS;
 905                 break;
 906 #else
 907                 {
 908                 op.op = KD_FONT_OP_SET_DEFAULT;
 909                 op.data = NULL;
 910                 ret = con_font_op(vc_cons[fg_console].d, &op);
 911                 if (ret)
 912                         break;
 913                 con_set_default_unimap(vc_cons[fg_console].d);
 914                 break;
 915                 }
 916 #endif
 917         }
 918
 919         case KDFONTOP: {
 920                 if (copy_from_user(&op, up, sizeof(op))) {
 921                         ret = -EFAULT;
 922                         break;
 923                 }
 924                 if (!perm && op.op != KD_FONT_OP_GET)
 925                         return -EPERM;
 926                 ret = con_font_op(vc, &op);
 927                 if (ret)
 928                         break;
 929                 if (copy_to_user(up, &op, sizeof(op)))
 930                         ret = -EFAULT;
 931                 break;
 932         }
 933
 934         case PIO_SCRNMAP:
 935                 if (!perm)
 936                         ret = -EPERM;
 937                 else {
 938                         tty_lock();
 939                         ret = con_set_trans_old(up);
 940                         tty_unlock();
 941                 }
 942                 break;
 943
 944         case GIO_SCRNMAP:
 945                 tty_lock();
 946                 ret = con_get_trans_old(up);
 947                 tty_unlock();
 948                 break;
 949
 950         case PIO_UNISCRNMAP:
 951                 if (!perm)
 952                         ret = -EPERM;
 953                 else {
 954                         tty_lock();
 955                         ret = con_set_trans_new(up);
 956                         tty_unlock();
 957                 }
 958                 break;
 959
 960         case GIO_UNISCRNMAP:
 961                 tty_lock();
 962                 ret = con_get_trans_new(up);
 963                 tty_unlock();
 964                 break;
 965
 966         case PIO_UNIMAPCLR:
 967               { struct unimapinit ui;
 968                 if (!perm)
 969                         return -EPERM;
 970                 ret = copy_from_user(&ui, up, sizeof(struct unimapinit));
 971                 if (ret)
 972                         ret = -EFAULT;
 973                 else {
 974                         tty_lock();
 975                         con_clear_unimap(vc, &ui);
 976                         tty_unlock();
 977                 }
 978                 break;
 979               }
 980
 981         case PIO_UNIMAP:
 982         case GIO_UNIMAP:
 983                 tty_lock();
 984                 ret = do_unimap_ioctl(cmd, up, perm, vc);
 985                 tty_unlock();
 986                 break;
 987
 988         case VT_LOCKSWITCH:
 989                 if (!capable(CAP_SYS_TTY_CONFIG))
 990                         return -EPERM;
 991                 vt_dont_switch = 1;
 992                 break;
 993         case VT_UNLOCKSWITCH:
 994                 if (!capable(CAP_SYS_TTY_CONFIG))
 995                         return -EPERM;
 996                 vt_dont_switch = 0;
 997                 break;
 998         case VT_GETHIFONTMASK:
 999                 ret = put_user(vc->vc_hi_font_mask,
1000                                         (unsigned short __user *)arg);
1001                 break;
1002         case VT_WAITEVENT:
1003                 ret = vt_event_wait_ioctl((struct vt_event __user *)arg);
1004                 break;
1005         default:
1006                 ret = -ENOIOCTLCMD;
1007         }
1008 out:
1009         return ret;
1010 }
1011
1012 void reset_vc(struct vc_data *vc)
1013 {
1014         vc->vc_mode = KD_TEXT;
1015         vt_reset_unicode(vc->vc_num);
1016         vc->vt_mode.mode = VT_AUTO;
1017         vc->vt_mode.waitv = 0;
1018         vc->vt_mode.relsig = 0;
1019         vc->vt_mode.acqsig = 0;
1020         vc->vt_mode.frsig = 0;
1021         put_pid(vc->vt_pid);
1022         vc->vt_pid = NULL;
1023         vc->vt_newvt = -1;
1024         if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
1025                 reset_palette(vc);
1026 }
1027
1028 void vc_SAK(struct work_struct *work)
1029 {
1030         struct vc *vc_con =
1031                 container_of(work, struct vc, SAK_work);
1032         struct vc_data *vc;
1033         struct tty_struct *tty;
1034
1035         console_lock();
1036         vc = vc_con->d;
1037         if (vc) {
1038                 /* FIXME: review tty ref counting */
1039                 tty = vc->port.tty;
1040                 /*
1041                  * SAK should also work in all raw modes and reset
1042                  * them properly.
1043                  */
1044                 if (tty)
1045                         __do_SAK(tty);
1046                 reset_vc(vc);
1047         }
1048         console_unlock();
1049 }
1050
1051 #ifdef CONFIG_COMPAT
1052
1053 struct compat_consolefontdesc {
1054         unsigned short charcount;       /* characters in font (256 or 512) */
1055         unsigned short charheight;      /* scan lines per character (1-32) */
1056         compat_caddr_t chardata;        /* font data in expanded form */
1057 };
1058
1059 static inline int
1060 compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
1061                          int perm, struct console_font_op *op)
1062 {
1063         struct compat_consolefontdesc cfdarg;
1064         int i;
1065
1066         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1067                 return -EFAULT;
1068
1069         switch (cmd) {
1070         case PIO_FONTX:
1071                 if (!perm)
1072                         return -EPERM;
1073                 op->op = KD_FONT_OP_SET;
1074                 op->flags = KD_FONT_FLAG_OLD;
1075                 op->width = 8;
1076                 op->height = cfdarg.charheight;
1077                 op->charcount = cfdarg.charcount;
1078                 op->data = compat_ptr(cfdarg.chardata);
1079                 return con_font_op(vc_cons[fg_console].d, op);
1080         case GIO_FONTX:
1081                 op->op = KD_FONT_OP_GET;
1082                 op->flags = KD_FONT_FLAG_OLD;
1083                 op->width = 8;
1084                 op->height = cfdarg.charheight;
1085                 op->charcount = cfdarg.charcount;
1086                 op->data = compat_ptr(cfdarg.chardata);
1087                 i = con_font_op(vc_cons[fg_console].d, op);
1088                 if (i)
1089                         return i;
1090                 cfdarg.charheight = op->height;
1091                 cfdarg.charcount = op->charcount;
1092                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1093                         return -EFAULT;
1094                 return 0;
1095         }
1096         return -EINVAL;
1097 }
1098
1099 struct compat_console_font_op {
1100         compat_uint_t op;        /* operation code KD_FONT_OP_* */
1101         compat_uint_t flags;     /* KD_FONT_FLAG_* */
1102         compat_uint_t width, height;     /* font size */
1103         compat_uint_t charcount;
1104         compat_caddr_t data;    /* font data with height fixed to 32 */
1105 };
1106
1107 static inline int
1108 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1109                          int perm, struct console_font_op *op, struct vc_data *vc)
1110 {
1111         int i;
1112
1113         if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1114                 return -EFAULT;
1115         if (!perm && op->op != KD_FONT_OP_GET)
1116                 return -EPERM;
1117         op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1118         i = con_font_op(vc, op);
1119         if (i)
1120                 return i;
1121         ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1122         if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1123                 return -EFAULT;
1124         return 0;
1125 }
1126
1127 struct compat_unimapdesc {
1128         unsigned short entry_ct;
1129         compat_caddr_t entries;
1130 };
1131
1132 static inline int
1133 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1134                          int perm, struct vc_data *vc)
1135 {
1136         struct compat_unimapdesc tmp;
1137         struct unipair __user *tmp_entries;
1138
1139         if (copy_from_user(&tmp, user_ud, sizeof tmp))
1140                 return -EFAULT;
1141         tmp_entries = compat_ptr(tmp.entries);
1142         if (tmp_entries)
1143                 if (!access_ok(VERIFY_WRITE, tmp_entries,
1144                                 tmp.entry_ct*sizeof(struct unipair)))
1145                         return -EFAULT;
1146         switch (cmd) {
1147         case PIO_UNIMAP:
1148                 if (!perm)
1149                         return -EPERM;
1150                 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1151         case GIO_UNIMAP:
1152                 if (!perm && fg_console != vc->vc_num)
1153                         return -EPERM;
1154                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1155         }
1156         return 0;
1157 }
1158
1159 long vt_compat_ioctl(struct tty_struct *tty,
1160              unsigned int cmd, unsigned long arg)
1161 {
1162         struct vc_data *vc = tty->driver_data;
1163         struct console_font_op op;      /* used in multiple places here */
1164         unsigned int console;
1165         void __user *up = (void __user *)arg;
1166         int perm;
1167         int ret = 0;
1168
1169         console = vc->vc_num;
1170
1171         if (!vc_cons_allocated(console)) {      /* impossible? */
1172                 ret = -ENOIOCTLCMD;
1173                 goto out;
1174         }
1175
1176         /*
1177          * To have permissions to do most of the vt ioctls, we either have
1178          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1179          */
1180         perm = 0;
1181         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1182                 perm = 1;
1183
1184         switch (cmd) {
1185         /*
1186          * these need special handlers for incompatible data structures
1187          */
1188         case PIO_FONTX:
1189         case GIO_FONTX:
1190                 ret = compat_fontx_ioctl(cmd, up, perm, &op);
1191                 break;
1192
1193         case KDFONTOP:
1194                 ret = compat_kdfontop_ioctl(up, perm, &op, vc);
1195                 break;
1196
1197         case PIO_UNIMAP:
1198         case GIO_UNIMAP:
1199                 tty_lock();
1200                 ret = compat_unimap_ioctl(cmd, up, perm, vc);
1201                 tty_unlock();
1202                 break;
1203
1204         /*
1205          * all these treat 'arg' as an integer
1206          */
1207         case KIOCSOUND:
1208         case KDMKTONE:
1209 #ifdef CONFIG_X86
1210         case KDADDIO:
1211         case KDDELIO:
1212 #endif
1213         case KDSETMODE:
1214         case KDMAPDISP:
1215         case KDUNMAPDISP:
1216         case KDSKBMODE:
1217         case KDSKBMETA:
1218         case KDSKBLED:
1219         case KDSETLED:
1220         case KDSIGACCEPT:
1221         case VT_ACTIVATE:
1222         case VT_WAITACTIVE:
1223         case VT_RELDISP:
1224         case VT_DISALLOCATE:
1225         case VT_RESIZE:
1226         case VT_RESIZEX:
1227                 goto fallback;
1228
1229         /*
1230          * the rest has a compatible data structure behind arg,
1231          * but we have to convert it to a proper 64 bit pointer.
1232          */
1233         default:
1234                 arg = (unsigned long)compat_ptr(arg);
1235                 goto fallback;
1236         }
1237 out:
1238         return ret;
1239
1240 fallback:
1241         return vt_ioctl(tty, cmd, arg);
1242 }
1243
1244
1245 #endif /* CONFIG_COMPAT */
1246
1247
1248 /*
1249  * Performs the back end of a vt switch. Called under the console
1250  * semaphore.
1251  */
1252 static void complete_change_console(struct vc_data *vc)
1253 {
1254         unsigned char old_vc_mode;
1255         int old = fg_console;
1256
1257         last_console = fg_console;
1258
1259         /*
1260          * If we're switching, we could be going from KD_GRAPHICS to
1261          * KD_TEXT mode or vice versa, which means we need to blank or
1262          * unblank the screen later.
1263          */
1264         old_vc_mode = vc_cons[fg_console].d->vc_mode;
1265         switch_screen(vc);
1266
1267         /*
1268          * This can't appear below a successful kill_pid().  If it did,
1269          * then the *blank_screen operation could occur while X, having
1270          * received acqsig, is waking up on another processor.  This
1271          * condition can lead to overlapping accesses to the VGA range
1272          * and the framebuffer (causing system lockups).
1273          *
1274          * To account for this we duplicate this code below only if the
1275          * controlling process is gone and we've called reset_vc.
1276          */
1277         if (old_vc_mode != vc->vc_mode) {
1278                 if (vc->vc_mode == KD_TEXT)
1279                         do_unblank_screen(1);
1280                 else
1281                         do_blank_screen(1);
1282         }
1283
1284         /*
1285          * If this new console is under process control, send it a signal
1286          * telling it that it has acquired. Also check if it has died and
1287          * clean up (similar to logic employed in change_console())
1288          */
1289         if (vc->vt_mode.mode == VT_PROCESS) {
1290                 /*
1291                  * Send the signal as privileged - kill_pid() will
1292                  * tell us if the process has gone or something else
1293                  * is awry
1294                  */
1295                 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1296                 /*
1297                  * The controlling process has died, so we revert back to
1298                  * normal operation. In this case, we'll also change back
1299                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1300                  * but it saves the agony when the X server dies and the screen
1301                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1302                  * this outside of VT_PROCESS but there is no single process
1303                  * to account for and tracking tty count may be undesirable.
1304                  */
1305                         reset_vc(vc);
1306
1307                         if (old_vc_mode != vc->vc_mode) {
1308                                 if (vc->vc_mode == KD_TEXT)
1309                                         do_unblank_screen(1);
1310                                 else
1311                                         do_blank_screen(1);
1312                         }
1313                 }
1314         }
1315
1316         /*
1317          * Wake anyone waiting for their VT to activate
1318          */
1319         vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1320         return;
1321 }
1322
1323 /*
1324  * Performs the front-end of a vt switch
1325  */
1326 void change_console(struct vc_data *new_vc)
1327 {
1328         struct vc_data *vc;
1329
1330         if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1331                 return;
1332
1333         /*
1334          * If this vt is in process mode, then we need to handshake with
1335          * that process before switching. Essentially, we store where that
1336          * vt wants to switch to and wait for it to tell us when it's done
1337          * (via VT_RELDISP ioctl).
1338          *
1339          * We also check to see if the controlling process still exists.
1340          * If it doesn't, we reset this vt to auto mode and continue.
1341          * This is a cheap way to track process control. The worst thing
1342          * that can happen is: we send a signal to a process, it dies, and
1343          * the switch gets "lost" waiting for a response; hopefully, the
1344          * user will try again, we'll detect the process is gone (unless
1345          * the user waits just the right amount of time :-) and revert the
1346          * vt to auto control.
1347          */
1348         vc = vc_cons[fg_console].d;
1349         if (vc->vt_mode.mode == VT_PROCESS) {
1350                 /*
1351                  * Send the signal as privileged - kill_pid() will
1352                  * tell us if the process has gone or something else
1353                  * is awry.
1354                  *
1355                  * We need to set vt_newvt *before* sending the signal or we
1356                  * have a race.
1357                  */
1358                 vc->vt_newvt = new_vc->vc_num;
1359                 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1360                         /*
1361                          * It worked. Mark the vt to switch to and
1362                          * return. The process needs to send us a
1363                          * VT_RELDISP ioctl to complete the switch.
1364                          */
1365                         return;
1366                 }
1367
1368                 /*
1369                  * The controlling process has died, so we revert back to
1370                  * normal operation. In this case, we'll also change back
1371                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1372                  * but it saves the agony when the X server dies and the screen
1373                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1374                  * this outside of VT_PROCESS but there is no single process
1375                  * to account for and tracking tty count may be undesirable.
1376                  */
1377                 reset_vc(vc);
1378
1379                 /*
1380                  * Fall through to normal (VT_AUTO) handling of the switch...
1381                  */
1382         }
1383
1384         /*
1385          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1386          */
1387         if (vc->vc_mode == KD_GRAPHICS)
1388                 return;
1389
1390         complete_change_console(new_vc);
1391 }
1392
1393 /* Perform a kernel triggered VT switch for suspend/resume */
1394
1395 static int disable_vt_switch;
1396
1397 int vt_move_to_console(unsigned int vt, int alloc)
1398 {
1399         int prev;
1400
1401         console_lock();
1402         /* Graphics mode - up to X */
1403         if (disable_vt_switch) {
1404                 console_unlock();
1405                 return 0;
1406         }
1407         prev = fg_console;
1408
1409         if (alloc && vc_allocate(vt)) {
1410                 /* we can't have a free VC for now. Too bad,
1411                  * we don't want to mess the screen for now. */
1412                 console_unlock();
1413                 return -ENOSPC;
1414         }
1415
1416         if (set_console(vt)) {
1417                 /*
1418                  * We're unable to switch to the SUSPEND_CONSOLE.
1419                  * Let the calling function know so it can decide
1420                  * what to do.
1421                  */
1422                 console_unlock();
1423                 return -EIO;
1424         }
1425         console_unlock();
1426         if (vt_waitactive(vt + 1)) {
1427                 pr_debug("Suspend: Can't switch VCs.");
1428                 return -EINTR;
1429         }
1430         return prev;
1431 }
1432
1433 /*
1434  * Normally during a suspend, we allocate a new console and switch to it.
1435  * When we resume, we switch back to the original console.  This switch
1436  * can be slow, so on systems where the framebuffer can handle restoration
1437  * of video registers anyways, there's little point in doing the console
1438  * switch.  This function allows you to disable it by passing it '0'.
1439  */
1440 void pm_set_vt_switch(int do_switch)
1441 {
1442         console_lock();
1443         disable_vt_switch = !do_switch;
1444         console_unlock();
1445 }
1446 EXPORT_SYMBOL(pm_set_vt_switch);