drivers/tty/vt/vt_ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 1992 obz under the linux copyright
   4  *
   5  *  Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
   6  *  Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
   7  *  Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
   8  *  Some code moved for less code duplication - Andi Kleen - Mar 1997
   9  *  Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/errno.h>
  14 #include <linux/sched/signal.h>
  15 #include <linux/tty.h>
  16 #include <linux/timer.h>
  17 #include <linux/kernel.h>
  18 #include <linux/compat.h>
  19 #include <linux/module.h>
  20 #include <linux/kd.h>
  21 #include <linux/vt.h>
  22 #include <linux/string.h>
  23 #include <linux/slab.h>
  24 #include <linux/major.h>
  25 #include <linux/fs.h>
  26 #include <linux/console.h>
  27 #include <linux/consolemap.h>
  28 #include <linux/signal.h>
  29 #include <linux/suspend.h>
  30 #include <linux/timex.h>
  31
  32 #include <asm/io.h>
  33 #include <linux/uaccess.h>
  34
  35 #include <linux/nospec.h>
  36
  37 #include <linux/kbd_kern.h>
  38 #include <linux/vt_kern.h>
  39 #include <linux/kbd_diacr.h>
  40 #include <linux/selection.h>
  41
  42 bool vt_dont_switch;
  43
  44 static inline bool vt_in_use(unsigned int i)
  45 {
  46         const struct vc_data *vc = vc_cons[i].d;
  47
  48         /*
  49          * console_lock must be held to prevent the vc from being deallocated
  50          * while we're checking whether it's in-use.
  51          */
  52         WARN_CONSOLE_UNLOCKED();
  53
  54         return vc && kref_read(&vc->port.kref) > 1;
  55 }
  56
  57 static inline bool vt_busy(int i)
  58 {
  59         if (vt_in_use(i))
  60                 return true;
  61         if (i == fg_console)
  62                 return true;
  63         if (vc_is_sel(vc_cons[i].d))
  64                 return true;
  65
  66         return false;
  67 }
  68
  69 /*
  70  * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
  71  * experimentation and study of X386 SYSV handling.
  72  *
  73  * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
  74  * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
  75  * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
  76  * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
  77  * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
  78  * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
  79  * to the current console is done by the main ioctl code.
  80  */
  81
  82 #ifdef CONFIG_X86
  83 #include <asm/syscalls.h>
  84 #endif
  85
  86 static void complete_change_console(struct vc_data *vc);
  87
  88 /*
  89  *      User space VT_EVENT handlers
  90  */
  91
  92 struct vt_event_wait {
  93         struct list_head list;
  94         struct vt_event event;
  95         int done;
  96 };
  97
  98 static LIST_HEAD(vt_events);
  99 static DEFINE_SPINLOCK(vt_event_lock);
 100 static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
 101
 102 /**
 103  *      vt_event_post
 104  *      @event: the event that occurred
 105  *      @old: old console
 106  *      @new: new console
 107  *
 108  *      Post an VT event to interested VT handlers
 109  */
 110
 111 void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
 112 {
 113         struct list_head *pos, *head;
 114         unsigned long flags;
 115         int wake = 0;
 116
 117         spin_lock_irqsave(&vt_event_lock, flags);
 118         head = &vt_events;
 119
 120         list_for_each(pos, head) {
 121                 struct vt_event_wait *ve = list_entry(pos,
 122                                                 struct vt_event_wait, list);
 123                 if (!(ve->event.event & event))
 124                         continue;
 125                 ve->event.event = event;
 126                 /* kernel view is consoles 0..n-1, user space view is
 127                    console 1..n with 0 meaning current, so we must bias */
 128                 ve->event.oldev = old + 1;
 129                 ve->event.newev = new + 1;
 130                 wake = 1;
 131                 ve->done = 1;
 132         }
 133         spin_unlock_irqrestore(&vt_event_lock, flags);
 134         if (wake)
 135                 wake_up_interruptible(&vt_event_waitqueue);
 136 }
 137
 138 static void __vt_event_queue(struct vt_event_wait *vw)
 139 {
 140         unsigned long flags;
 141         /* Prepare the event */
 142         INIT_LIST_HEAD(&vw->list);
 143         vw->done = 0;
 144         /* Queue our event */
 145         spin_lock_irqsave(&vt_event_lock, flags);
 146         list_add(&vw->list, &vt_events);
 147         spin_unlock_irqrestore(&vt_event_lock, flags);
 148 }
 149
 150 static void __vt_event_wait(struct vt_event_wait *vw)
 151 {
 152         /* Wait for it to pass */
 153         wait_event_interruptible(vt_event_waitqueue, vw->done);
 154 }
 155
 156 static void __vt_event_dequeue(struct vt_event_wait *vw)
 157 {
 158         unsigned long flags;
 159
 160         /* Dequeue it */
 161         spin_lock_irqsave(&vt_event_lock, flags);
 162         list_del(&vw->list);
 163         spin_unlock_irqrestore(&vt_event_lock, flags);
 164 }
 165
 166 /**
 167  *      vt_event_wait           -       wait for an event
 168  *      @vw: our event
 169  *
 170  *      Waits for an event to occur which completes our vt_event_wait
 171  *      structure. On return the structure has wv->done set to 1 for success
 172  *      or 0 if some event such as a signal ended the wait.
 173  */
 174
 175 static void vt_event_wait(struct vt_event_wait *vw)
 176 {
 177         __vt_event_queue(vw);
 178         __vt_event_wait(vw);
 179         __vt_event_dequeue(vw);
 180 }
 181
 182 /**
 183  *      vt_event_wait_ioctl     -       event ioctl handler
 184  *      @event: argument to ioctl (the event)
 185  *
 186  *      Implement the VT_WAITEVENT ioctl using the VT event interface
 187  */
 188
 189 static int vt_event_wait_ioctl(struct vt_event __user *event)
 190 {
 191         struct vt_event_wait vw;
 192
 193         if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
 194                 return -EFAULT;
 195         /* Highest supported event for now */
 196         if (vw.event.event & ~VT_MAX_EVENT)
 197                 return -EINVAL;
 198
 199         vt_event_wait(&vw);
 200         /* If it occurred report it */
 201         if (vw.done) {
 202                 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
 203                         return -EFAULT;
 204                 return 0;
 205         }
 206         return -EINTR;
 207 }
 208
 209 /**
 210  *      vt_waitactive   -       active console wait
 211  *      @n: new console
 212  *
 213  *      Helper for event waits. Used to implement the legacy
 214  *      event waiting ioctls in terms of events
 215  */
 216
 217 int vt_waitactive(int n)
 218 {
 219         struct vt_event_wait vw;
 220         do {
 221                 vw.event.event = VT_EVENT_SWITCH;
 222                 __vt_event_queue(&vw);
 223                 if (n == fg_console + 1) {
 224                         __vt_event_dequeue(&vw);
 225                         break;
 226                 }
 227                 __vt_event_wait(&vw);
 228                 __vt_event_dequeue(&vw);
 229                 if (vw.done == 0)
 230                         return -EINTR;
 231         } while (vw.event.newev != n);
 232         return 0;
 233 }
 234
 235 /*
 236  * these are the valid i/o ports we're allowed to change. they map all the
 237  * video ports
 238  */
 239 #define GPFIRST 0x3b4
 240 #define GPLAST 0x3df
 241 #define GPNUM (GPLAST - GPFIRST + 1)
 242
 243 /*
 244  * currently, setting the mode from KD_TEXT to KD_GRAPHICS doesn't do a whole
 245  * lot. i'm not sure if it should do any restoration of modes or what...
 246  *
 247  * XXX It should at least call into the driver, fbdev's definitely need to
 248  * restore their engine state. --BenH
 249  */
 250 static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
 251 {
 252         switch (mode) {
 253         case KD_GRAPHICS:
 254                 break;
 255         case KD_TEXT0:
 256         case KD_TEXT1:
 257                 mode = KD_TEXT;
 258                 fallthrough;
 259         case KD_TEXT:
 260                 break;
 261         default:
 262                 return -EINVAL;
 263         }
 264
 265         /* FIXME: this needs the console lock extending */
 266         if (vc->vc_mode == mode)
 267                 return 0;
 268
 269         vc->vc_mode = mode;
 270         if (vc->vc_num != fg_console)
 271                 return 0;
 272
 273         /* explicitly blank/unblank the screen if switching modes */
 274         console_lock();
 275         if (mode == KD_TEXT)
 276                 do_unblank_screen(1);
 277         else
 278                 do_blank_screen(1);
 279         console_unlock();
 280
 281         return 0;
 282 }
 283
 284 static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
 285                 unsigned long arg, bool perm)
 286 {
 287         struct vc_data *vc = tty->driver_data;
 288         void __user *up = (void __user *)arg;
 289         unsigned int console = vc->vc_num;
 290         int ret;
 291
 292         switch (cmd) {
 293         case KIOCSOUND:
 294                 if (!perm)
 295                         return -EPERM;
 296                 /*
 297                  * The use of PIT_TICK_RATE is historic, it used to be
 298                  * the platform-dependent CLOCK_TICK_RATE between 2.6.12
 299                  * and 2.6.36, which was a minor but unfortunate ABI
 300                  * change. kd_mksound is locked by the input layer.
 301                  */
 302                 if (arg)
 303                         arg = PIT_TICK_RATE / arg;
 304                 kd_mksound(arg, 0);
 305                 break;
 306
 307         case KDMKTONE:
 308                 if (!perm)
 309                         return -EPERM;
 310         {
 311                 unsigned int ticks, count;
 312
 313                 /*
 314                  * Generate the tone for the appropriate number of ticks.
 315                  * If the time is zero, turn off sound ourselves.
 316                  */
 317                 ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
 318                 count = ticks ? (arg & 0xffff) : 0;
 319                 if (count)
 320                         count = PIT_TICK_RATE / count;
 321                 kd_mksound(count, ticks);
 322                 break;
 323         }
 324
 325         case KDGKBTYPE:
 326                 /*
 327                  * this is naïve.
 328                  */
 329                 return put_user(KB_101, (char __user *)arg);
 330
 331                 /*
 332                  * These cannot be implemented on any machine that implements
 333                  * ioperm() in user level (such as Alpha PCs) or not at all.
 334                  *
 335                  * XXX: you should never use these, just call ioperm directly..
 336                  */
 337 #ifdef CONFIG_X86
 338         case KDADDIO:
 339         case KDDELIO:
 340                 /*
 341                  * KDADDIO and KDDELIO may be able to add ports beyond what
 342                  * we reject here, but to be safe...
 343                  *
 344                  * These are locked internally via sys_ioperm
 345                  */
 346                 if (arg < GPFIRST || arg > GPLAST)
 347                         return -EINVAL;
 348
 349                 return ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 350
 351         case KDENABIO:
 352         case KDDISABIO:
 353                 return ksys_ioperm(GPFIRST, GPNUM,
 354                                   (cmd == KDENABIO)) ? -ENXIO : 0;
 355 #endif
 356
 357         /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
 358
 359         case KDKBDREP:
 360         {
 361                 struct kbd_repeat kbrep;
 362
 363                 if (!capable(CAP_SYS_TTY_CONFIG))
 364                         return -EPERM;
 365
 366                 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
 367                         return -EFAULT;
 368
 369                 ret = kbd_rate(&kbrep);
 370                 if (ret)
 371                         return ret;
 372                 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
 373                         return -EFAULT;
 374                 break;
 375         }
 376
 377         case KDSETMODE:
 378                 if (!perm)
 379                         return -EPERM;
 380
 381                 return vt_kdsetmode(vc, arg);
 382
 383         case KDGETMODE:
 384                 return put_user(vc->vc_mode, (int __user *)arg);
 385
 386         case KDMAPDISP:
 387         case KDUNMAPDISP:
 388                 /*
 389                  * these work like a combination of mmap and KDENABIO.
 390                  * this could be easily finished.
 391                  */
 392                 return -EINVAL;
 393
 394         case KDSKBMODE:
 395                 if (!perm)
 396                         return -EPERM;
 397                 ret = vt_do_kdskbmode(console, arg);
 398                 if (ret)
 399                         return ret;
 400                 tty_ldisc_flush(tty);
 401                 break;
 402
 403         case KDGKBMODE:
 404                 return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
 405
 406         /* this could be folded into KDSKBMODE, but for compatibility
 407            reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 408         case KDSKBMETA:
 409                 return vt_do_kdskbmeta(console, arg);
 410
 411         case KDGKBMETA:
 412                 /* FIXME: should review whether this is worth locking */
 413                 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
 414
 415         case KDGETKEYCODE:
 416         case KDSETKEYCODE:
 417                 if(!capable(CAP_SYS_TTY_CONFIG))
 418                         perm = 0;
 419                 return vt_do_kbkeycode_ioctl(cmd, up, perm);
 420
 421         case KDGKBENT:
 422         case KDSKBENT:
 423                 return vt_do_kdsk_ioctl(cmd, up, perm, console);
 424
 425         case KDGKBSENT:
 426         case KDSKBSENT:
 427                 return vt_do_kdgkb_ioctl(cmd, up, perm);
 428
 429         /* Diacritical processing. Handled in keyboard.c as it has
 430            to operate on the keyboard locks and structures */
 431         case KDGKBDIACR:
 432         case KDGKBDIACRUC:
 433         case KDSKBDIACR:
 434         case KDSKBDIACRUC:
 435                 return vt_do_diacrit(cmd, up, perm);
 436
 437         /* the ioctls below read/set the flags usually shown in the leds */
 438         /* don't use them - they will go away without warning */
 439         case KDGKBLED:
 440         case KDSKBLED:
 441         case KDGETLED:
 442         case KDSETLED:
 443                 return vt_do_kdskled(console, cmd, arg, perm);
 444
 445         /*
 446          * A process can indicate its willingness to accept signals
 447          * generated by pressing an appropriate key combination.
 448          * Thus, one can have a daemon that e.g. spawns a new console
 449          * upon a keypress and then changes to it.
 450          * See also the kbrequest field of inittab(5).
 451          */
 452         case KDSIGACCEPT:
 453                 if (!perm || !capable(CAP_KILL))
 454                         return -EPERM;
 455                 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
 456                         return -EINVAL;
 457
 458                 spin_lock_irq(&vt_spawn_con.lock);
 459                 put_pid(vt_spawn_con.pid);
 460                 vt_spawn_con.pid = get_pid(task_pid(current));
 461                 vt_spawn_con.sig = arg;
 462                 spin_unlock_irq(&vt_spawn_con.lock);
 463                 break;
 464
 465         case KDFONTOP: {
 466                 struct console_font_op op;
 467
 468                 if (copy_from_user(&op, up, sizeof(op)))
 469                         return -EFAULT;
 470                 if (!perm && op.op != KD_FONT_OP_GET)
 471                         return -EPERM;
 472                 ret = con_font_op(vc, &op);
 473                 if (ret)
 474                         return ret;
 475                 if (copy_to_user(up, &op, sizeof(op)))
 476                         return -EFAULT;
 477                 break;
 478         }
 479
 480         default:
 481                 return -ENOIOCTLCMD;
 482         }
 483
 484         return 0;
 485 }
 486
 487 static inline int do_fontx_ioctl(struct vc_data *vc, int cmd,
 488                 struct consolefontdesc __user *user_cfd,
 489                 struct console_font_op *op)
 490 {
 491         struct consolefontdesc cfdarg;
 492         int i;
 493
 494         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
 495                 return -EFAULT;
 496
 497         switch (cmd) {
 498         case PIO_FONTX:
 499                 op->op = KD_FONT_OP_SET;
 500                 op->flags = KD_FONT_FLAG_OLD;
 501                 op->width = 8;
 502                 op->height = cfdarg.charheight;
 503                 op->charcount = cfdarg.charcount;
 504                 op->data = cfdarg.chardata;
 505                 return con_font_op(vc, op);
 506
 507         case GIO_FONTX:
 508                 op->op = KD_FONT_OP_GET;
 509                 op->flags = KD_FONT_FLAG_OLD;
 510                 op->width = 8;
 511                 op->height = cfdarg.charheight;
 512                 op->charcount = cfdarg.charcount;
 513                 op->data = cfdarg.chardata;
 514                 i = con_font_op(vc, op);
 515                 if (i)
 516                         return i;
 517                 cfdarg.charheight = op->height;
 518                 cfdarg.charcount = op->charcount;
 519                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
 520                         return -EFAULT;
 521                 return 0;
 522         }
 523         return -EINVAL;
 524 }
 525
 526 static int vt_io_fontreset(struct vc_data *vc, struct console_font_op *op)
 527 {
 528         int ret;
 529
 530         if (__is_defined(BROKEN_GRAPHICS_PROGRAMS)) {
 531                 /*
 532                  * With BROKEN_GRAPHICS_PROGRAMS defined, the default font is
 533                  * not saved.
 534                  */
 535                 return -ENOSYS;
 536         }
 537
 538         op->op = KD_FONT_OP_SET_DEFAULT;
 539         op->data = NULL;
 540         ret = con_font_op(vc, op);
 541         if (ret)
 542                 return ret;
 543
 544         console_lock();
 545         con_set_default_unimap(vc);
 546         console_unlock();
 547
 548         return 0;
 549 }
 550
 551 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
 552                 bool perm, struct vc_data *vc)
 553 {
 554         struct unimapdesc tmp;
 555
 556         if (copy_from_user(&tmp, user_ud, sizeof tmp))
 557                 return -EFAULT;
 558         switch (cmd) {
 559         case PIO_UNIMAP:
 560                 if (!perm)
 561                         return -EPERM;
 562                 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
 563         case GIO_UNIMAP:
 564                 if (!perm && fg_console != vc->vc_num)
 565                         return -EPERM;
 566                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
 567                                 tmp.entries);
 568         }
 569         return 0;
 570 }
 571
 572 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
 573                 bool perm)
 574 {
 575         struct console_font_op op;      /* used in multiple places here */
 576
 577         switch (cmd) {
 578         case PIO_FONT:
 579                 if (!perm)
 580                         return -EPERM;
 581                 op.op = KD_FONT_OP_SET;
 582                 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
 583                 op.width = 8;
 584                 op.height = 0;
 585                 op.charcount = 256;
 586                 op.data = up;
 587                 return con_font_op(vc, &op);
 588
 589         case GIO_FONT:
 590                 op.op = KD_FONT_OP_GET;
 591                 op.flags = KD_FONT_FLAG_OLD;
 592                 op.width = 8;
 593                 op.height = 32;
 594                 op.charcount = 256;
 595                 op.data = up;
 596                 return con_font_op(vc, &op);
 597
 598         case PIO_CMAP:
 599                 if (!perm)
 600                         return -EPERM;
 601                 return con_set_cmap(up);
 602
 603         case GIO_CMAP:
 604                 return con_get_cmap(up);
 605
 606         case PIO_FONTX:
 607                 if (!perm)
 608                         return -EPERM;
 609
 610                 fallthrough;
 611         case GIO_FONTX:
 612                 return do_fontx_ioctl(vc, cmd, up, &op);
 613
 614         case PIO_FONTRESET:
 615                 if (!perm)
 616                         return -EPERM;
 617
 618                 return vt_io_fontreset(vc, &op);
 619
 620         case PIO_SCRNMAP:
 621                 if (!perm)
 622                         return -EPERM;
 623                 return con_set_trans_old(up);
 624
 625         case GIO_SCRNMAP:
 626                 return con_get_trans_old(up);
 627
 628         case PIO_UNISCRNMAP:
 629                 if (!perm)
 630                         return -EPERM;
 631                 return con_set_trans_new(up);
 632
 633         case GIO_UNISCRNMAP:
 634                 return con_get_trans_new(up);
 635
 636         case PIO_UNIMAPCLR:
 637                 if (!perm)
 638                         return -EPERM;
 639                 con_clear_unimap(vc);
 640                 break;
 641
 642         case PIO_UNIMAP:
 643         case GIO_UNIMAP:
 644                 return do_unimap_ioctl(cmd, up, perm, vc);
 645
 646         default:
 647                 return -ENOIOCTLCMD;
 648         }
 649
 650         return 0;
 651 }
 652
 653 static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
 654 {
 655         int newvt, ret;
 656
 657         if (vc->vt_mode.mode != VT_PROCESS)
 658                 return -EINVAL;
 659
 660         /* Switched-to response */
 661         if (vc->vt_newvt < 0) {
 662                  /* If it's just an ACK, ignore it */
 663                 return swtch == VT_ACKACQ ? 0 : -EINVAL;
 664         }
 665
 666         /* Switching-from response */
 667         if (swtch == 0) {
 668                 /* Switch disallowed, so forget we were trying to do it. */
 669                 vc->vt_newvt = -1;
 670                 return 0;
 671         }
 672
 673         /* The current vt has been released, so complete the switch. */
 674         newvt = vc->vt_newvt;
 675         vc->vt_newvt = -1;
 676         ret = vc_allocate(newvt);
 677         if (ret)
 678                 return ret;
 679
 680         /*
 681          * When we actually do the console switch, make sure we are atomic with
 682          * respect to other console switches..
 683          */
 684         complete_change_console(vc_cons[newvt].d);
 685
 686         return 0;
 687 }
 688
 689 static int vt_setactivate(struct vt_setactivate __user *sa)
 690 {
 691         struct vt_setactivate vsa;
 692         struct vc_data *nvc;
 693         int ret;
 694
 695         if (copy_from_user(&vsa, sa, sizeof(vsa)))
 696                 return -EFAULT;
 697         if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
 698                 return -ENXIO;
 699
 700         vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES + 1);
 701         vsa.console--;
 702         console_lock();
 703         ret = vc_allocate(vsa.console);
 704         if (ret) {
 705                 console_unlock();
 706                 return ret;
 707         }
 708
 709         /*
 710          * This is safe providing we don't drop the console sem between
 711          * vc_allocate and finishing referencing nvc.
 712          */
 713         nvc = vc_cons[vsa.console].d;
 714         nvc->vt_mode = vsa.mode;
 715         nvc->vt_mode.frsig = 0;
 716         put_pid(nvc->vt_pid);
 717         nvc->vt_pid = get_pid(task_pid(current));
 718         console_unlock();
 719
 720         /* Commence switch and lock */
 721         /* Review set_console locks */
 722         set_console(vsa.console);
 723
 724         return 0;
 725 }
 726
 727 /* deallocate a single console, if possible (leave 0) */
 728 static int vt_disallocate(unsigned int vc_num)
 729 {
 730         struct vc_data *vc = NULL;
 731         int ret = 0;
 732
 733         console_lock();
 734         if (vt_busy(vc_num))
 735                 ret = -EBUSY;
 736         else if (vc_num)
 737                 vc = vc_deallocate(vc_num);
 738         console_unlock();
 739
 740         if (vc && vc_num >= MIN_NR_CONSOLES)
 741                 tty_port_put(&vc->port);
 742
 743         return ret;
 744 }
 745
 746 /* deallocate all unused consoles, but leave 0 */
 747 static void vt_disallocate_all(void)
 748 {
 749         struct vc_data *vc[MAX_NR_CONSOLES];
 750         int i;
 751
 752         console_lock();
 753         for (i = 1; i < MAX_NR_CONSOLES; i++)
 754                 if (!vt_busy(i))
 755                         vc[i] = vc_deallocate(i);
 756                 else
 757                         vc[i] = NULL;
 758         console_unlock();
 759
 760         for (i = 1; i < MAX_NR_CONSOLES; i++) {
 761                 if (vc[i] && i >= MIN_NR_CONSOLES)
 762                         tty_port_put(&vc[i]->port);
 763         }
 764 }
 765
 766 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
 767 {
 768         struct vt_consize v;
 769         int i;
 770
 771         if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
 772                 return -EFAULT;
 773
 774         if (v.v_vlin)
 775                 pr_info_once("\"struct vt_consize\"->v_vlin is ignored. Please report if you need this.\n");
 776         if (v.v_clin)
 777                 pr_info_once("\"struct vt_consize\"->v_clin is ignored. Please report if you need this.\n");
 778
 779         console_lock();
 780         for (i = 0; i < MAX_NR_CONSOLES; i++) {
 781                 vc = vc_cons[i].d;
 782
 783                 if (vc) {
 784                         vc->vc_resize_user = 1;
 785                         vc_resize(vc, v.v_cols, v.v_rows);
 786                 }
 787         }
 788         console_unlock();
 789
 790         return 0;
 791 }
 792
 793 /*
 794  * We handle the console-specific ioctl's here.  We allow the
 795  * capability to modify any console, not just the fg_console.
 796  */
 797 int vt_ioctl(struct tty_struct *tty,
 798              unsigned int cmd, unsigned long arg)
 799 {
 800         struct vc_data *vc = tty->driver_data;
 801         void __user *up = (void __user *)arg;
 802         int i, perm;
 803         int ret;
 804
 805         /*
 806          * To have permissions to do most of the vt ioctls, we either have
 807          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
 808          */
 809         perm = 0;
 810         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
 811                 perm = 1;
 812
 813         ret = vt_k_ioctl(tty, cmd, arg, perm);
 814         if (ret != -ENOIOCTLCMD)
 815                 return ret;
 816
 817         ret = vt_io_ioctl(vc, cmd, up, perm);
 818         if (ret != -ENOIOCTLCMD)
 819                 return ret;
 820
 821         switch (cmd) {
 822         case TIOCLINUX:
 823                 return tioclinux(tty, arg);
 824         case VT_SETMODE:
 825         {
 826                 struct vt_mode tmp;
 827
 828                 if (!perm)
 829                         return -EPERM;
 830                 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
 831                         return -EFAULT;
 832                 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
 833                         return -EINVAL;
 834
 835                 console_lock();
 836                 vc->vt_mode = tmp;
 837                 /* the frsig is ignored, so we set it to 0 */
 838                 vc->vt_mode.frsig = 0;
 839                 put_pid(vc->vt_pid);
 840                 vc->vt_pid = get_pid(task_pid(current));
 841                 /* no switch is required -- saw@shade.msu.ru */
 842                 vc->vt_newvt = -1;
 843                 console_unlock();
 844                 break;
 845         }
 846
 847         case VT_GETMODE:
 848         {
 849                 struct vt_mode tmp;
 850                 int rc;
 851
 852                 console_lock();
 853                 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
 854                 console_unlock();
 855
 856                 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
 857                 if (rc)
 858                         return -EFAULT;
 859                 break;
 860         }
 861
 862         /*
 863          * Returns global vt state. Note that VT 0 is always open, since
 864          * it's an alias for the current VT, and people can't use it here.
 865          * We cannot return state for more than 16 VTs, since v_state is short.
 866          */
 867         case VT_GETSTATE:
 868         {
 869                 struct vt_stat __user *vtstat = up;
 870                 unsigned short state, mask;
 871
 872                 if (put_user(fg_console + 1, &vtstat->v_active))
 873                         return -EFAULT;
 874
 875                 state = 1;      /* /dev/tty0 is always open */
 876                 console_lock(); /* required by vt_in_use() */
 877                 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
 878                                 ++i, mask <<= 1)
 879                         if (vt_in_use(i))
 880                                 state |= mask;
 881                 console_unlock();
 882                 return put_user(state, &vtstat->v_state);
 883         }
 884
 885         /*
 886          * Returns the first available (non-opened) console.
 887          */
 888         case VT_OPENQRY:
 889                 console_lock(); /* required by vt_in_use() */
 890                 for (i = 0; i < MAX_NR_CONSOLES; ++i)
 891                         if (!vt_in_use(i))
 892                                 break;
 893                 console_unlock();
 894                 i = i < MAX_NR_CONSOLES ? (i+1) : -1;
 895                 return put_user(i, (int __user *)arg);
 896
 897         /*
 898          * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
 899          * with num >= 1 (switches to vt 0, our console, are not allowed, just
 900          * to preserve sanity).
 901          */
 902         case VT_ACTIVATE:
 903                 if (!perm)
 904                         return -EPERM;
 905                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 906                         return -ENXIO;
 907
 908                 arg--;
 909                 console_lock();
 910                 ret = vc_allocate(arg);
 911                 console_unlock();
 912                 if (ret)
 913                         return ret;
 914                 set_console(arg);
 915                 break;
 916
 917         case VT_SETACTIVATE:
 918                 if (!perm)
 919                         return -EPERM;
 920
 921                 return vt_setactivate(up);
 922
 923         /*
 924          * wait until the specified VT has been activated
 925          */
 926         case VT_WAITACTIVE:
 927                 if (!perm)
 928                         return -EPERM;
 929                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 930                         return -ENXIO;
 931                 return vt_waitactive(arg);
 932
 933         /*
 934          * If a vt is under process control, the kernel will not switch to it
 935          * immediately, but postpone the operation until the process calls this
 936          * ioctl, allowing the switch to complete.
 937          *
 938          * According to the X sources this is the behavior:
 939          *      0:      pending switch-from not OK
 940          *      1:      pending switch-from OK
 941          *      2:      completed switch-to OK
 942          */
 943         case VT_RELDISP:
 944                 if (!perm)
 945                         return -EPERM;
 946
 947                 console_lock();
 948                 ret = vt_reldisp(vc, arg);
 949                 console_unlock();
 950
 951                 return ret;
 952
 953
 954          /*
 955           * Disallocate memory associated to VT (but leave VT1)
 956           */
 957          case VT_DISALLOCATE:
 958                 if (arg > MAX_NR_CONSOLES)
 959                         return -ENXIO;
 960
 961                 if (arg == 0)
 962                         vt_disallocate_all();
 963                 else
 964                         return vt_disallocate(--arg);
 965                 break;
 966
 967         case VT_RESIZE:
 968         {
 969                 struct vt_sizes __user *vtsizes = up;
 970                 struct vc_data *vc;
 971                 ushort ll,cc;
 972
 973                 if (!perm)
 974                         return -EPERM;
 975                 if (get_user(ll, &vtsizes->v_rows) ||
 976                     get_user(cc, &vtsizes->v_cols))
 977                         return -EFAULT;
 978
 979                 console_lock();
 980                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 981                         vc = vc_cons[i].d;
 982
 983                         if (vc) {
 984                                 vc->vc_resize_user = 1;
 985                                 /* FIXME: review v tty lock */
 986                                 vc_resize(vc_cons[i].d, cc, ll);
 987                         }
 988                 }
 989                 console_unlock();
 990                 break;
 991         }
 992
 993         case VT_RESIZEX:
 994                 if (!perm)
 995                         return -EPERM;
 996
 997                 return vt_resizex(vc, up);
 998
 999         case VT_LOCKSWITCH:
1000                 if (!capable(CAP_SYS_TTY_CONFIG))
1001                         return -EPERM;
1002                 vt_dont_switch = true;
1003                 break;
1004         case VT_UNLOCKSWITCH:
1005                 if (!capable(CAP_SYS_TTY_CONFIG))
1006                         return -EPERM;
1007                 vt_dont_switch = false;
1008                 break;
1009         case VT_GETHIFONTMASK:
1010                 return put_user(vc->vc_hi_font_mask,
1011                                         (unsigned short __user *)arg);
1012         case VT_WAITEVENT:
1013                 return vt_event_wait_ioctl((struct vt_event __user *)arg);
1014         default:
1015                 return -ENOIOCTLCMD;
1016         }
1017
1018         return 0;
1019 }
1020
1021 void reset_vc(struct vc_data *vc)
1022 {
1023         vc->vc_mode = KD_TEXT;
1024         vt_reset_unicode(vc->vc_num);
1025         vc->vt_mode.mode = VT_AUTO;
1026         vc->vt_mode.waitv = 0;
1027         vc->vt_mode.relsig = 0;
1028         vc->vt_mode.acqsig = 0;
1029         vc->vt_mode.frsig = 0;
1030         put_pid(vc->vt_pid);
1031         vc->vt_pid = NULL;
1032         vc->vt_newvt = -1;
1033         if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
1034                 reset_palette(vc);
1035 }
1036
1037 void vc_SAK(struct work_struct *work)
1038 {
1039         struct vc *vc_con =
1040                 container_of(work, struct vc, SAK_work);
1041         struct vc_data *vc;
1042         struct tty_struct *tty;
1043
1044         console_lock();
1045         vc = vc_con->d;
1046         if (vc) {
1047                 /* FIXME: review tty ref counting */
1048                 tty = vc->port.tty;
1049                 /*
1050                  * SAK should also work in all raw modes and reset
1051                  * them properly.
1052                  */
1053                 if (tty)
1054                         __do_SAK(tty);
1055                 reset_vc(vc);
1056         }
1057         console_unlock();
1058 }
1059
1060 #ifdef CONFIG_COMPAT
1061
1062 struct compat_consolefontdesc {
1063         unsigned short charcount;       /* characters in font (256 or 512) */
1064         unsigned short charheight;      /* scan lines per character (1-32) */
1065         compat_caddr_t chardata;        /* font data in expanded form */
1066 };
1067
1068 static inline int
1069 compat_fontx_ioctl(struct vc_data *vc, int cmd,
1070                    struct compat_consolefontdesc __user *user_cfd,
1071                    int perm, struct console_font_op *op)
1072 {
1073         struct compat_consolefontdesc cfdarg;
1074         int i;
1075
1076         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1077                 return -EFAULT;
1078
1079         switch (cmd) {
1080         case PIO_FONTX:
1081                 if (!perm)
1082                         return -EPERM;
1083                 op->op = KD_FONT_OP_SET;
1084                 op->flags = KD_FONT_FLAG_OLD;
1085                 op->width = 8;
1086                 op->height = cfdarg.charheight;
1087                 op->charcount = cfdarg.charcount;
1088                 op->data = compat_ptr(cfdarg.chardata);
1089                 return con_font_op(vc, op);
1090
1091         case GIO_FONTX:
1092                 op->op = KD_FONT_OP_GET;
1093                 op->flags = KD_FONT_FLAG_OLD;
1094                 op->width = 8;
1095                 op->height = cfdarg.charheight;
1096                 op->charcount = cfdarg.charcount;
1097                 op->data = compat_ptr(cfdarg.chardata);
1098                 i = con_font_op(vc, op);
1099                 if (i)
1100                         return i;
1101                 cfdarg.charheight = op->height;
1102                 cfdarg.charcount = op->charcount;
1103                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1104                         return -EFAULT;
1105                 return 0;
1106         }
1107         return -EINVAL;
1108 }
1109
1110 struct compat_console_font_op {
1111         compat_uint_t op;        /* operation code KD_FONT_OP_* */
1112         compat_uint_t flags;     /* KD_FONT_FLAG_* */
1113         compat_uint_t width, height;     /* font size */
1114         compat_uint_t charcount;
1115         compat_caddr_t data;    /* font data with height fixed to 32 */
1116 };
1117
1118 static inline int
1119 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1120                          int perm, struct console_font_op *op, struct vc_data *vc)
1121 {
1122         int i;
1123
1124         if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1125                 return -EFAULT;
1126         if (!perm && op->op != KD_FONT_OP_GET)
1127                 return -EPERM;
1128         op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1129         i = con_font_op(vc, op);
1130         if (i)
1131                 return i;
1132         ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1133         if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1134                 return -EFAULT;
1135         return 0;
1136 }
1137
1138 struct compat_unimapdesc {
1139         unsigned short entry_ct;
1140         compat_caddr_t entries;
1141 };
1142
1143 static inline int
1144 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1145                          int perm, struct vc_data *vc)
1146 {
1147         struct compat_unimapdesc tmp;
1148         struct unipair __user *tmp_entries;
1149
1150         if (copy_from_user(&tmp, user_ud, sizeof tmp))
1151                 return -EFAULT;
1152         tmp_entries = compat_ptr(tmp.entries);
1153         switch (cmd) {
1154         case PIO_UNIMAP:
1155                 if (!perm)
1156                         return -EPERM;
1157                 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1158         case GIO_UNIMAP:
1159                 if (!perm && fg_console != vc->vc_num)
1160                         return -EPERM;
1161                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1162         }
1163         return 0;
1164 }
1165
1166 long vt_compat_ioctl(struct tty_struct *tty,
1167              unsigned int cmd, unsigned long arg)
1168 {
1169         struct vc_data *vc = tty->driver_data;
1170         struct console_font_op op;      /* used in multiple places here */
1171         void __user *up = compat_ptr(arg);
1172         int perm;
1173
1174         /*
1175          * To have permissions to do most of the vt ioctls, we either have
1176          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1177          */
1178         perm = 0;
1179         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1180                 perm = 1;
1181
1182         switch (cmd) {
1183         /*
1184          * these need special handlers for incompatible data structures
1185          */
1186         case PIO_FONTX:
1187         case GIO_FONTX:
1188                 return compat_fontx_ioctl(vc, cmd, up, perm, &op);
1189
1190         case KDFONTOP:
1191                 return compat_kdfontop_ioctl(up, perm, &op, vc);
1192
1193         case PIO_UNIMAP:
1194         case GIO_UNIMAP:
1195                 return compat_unimap_ioctl(cmd, up, perm, vc);
1196
1197         /*
1198          * all these treat 'arg' as an integer
1199          */
1200         case KIOCSOUND:
1201         case KDMKTONE:
1202 #ifdef CONFIG_X86
1203         case KDADDIO:
1204         case KDDELIO:
1205 #endif
1206         case KDSETMODE:
1207         case KDMAPDISP:
1208         case KDUNMAPDISP:
1209         case KDSKBMODE:
1210         case KDSKBMETA:
1211         case KDSKBLED:
1212         case KDSETLED:
1213         case KDSIGACCEPT:
1214         case VT_ACTIVATE:
1215         case VT_WAITACTIVE:
1216         case VT_RELDISP:
1217         case VT_DISALLOCATE:
1218         case VT_RESIZE:
1219         case VT_RESIZEX:
1220                 return vt_ioctl(tty, cmd, arg);
1221
1222         /*
1223          * the rest has a compatible data structure behind arg,
1224          * but we have to convert it to a proper 64 bit pointer.
1225          */
1226         default:
1227                 return vt_ioctl(tty, cmd, (unsigned long)up);
1228         }
1229 }
1230
1231
1232 #endif /* CONFIG_COMPAT */
1233
1234
1235 /*
1236  * Performs the back end of a vt switch. Called under the console
1237  * semaphore.
1238  */
1239 static void complete_change_console(struct vc_data *vc)
1240 {
1241         unsigned char old_vc_mode;
1242         int old = fg_console;
1243
1244         last_console = fg_console;
1245
1246         /*
1247          * If we're switching, we could be going from KD_GRAPHICS to
1248          * KD_TEXT mode or vice versa, which means we need to blank or
1249          * unblank the screen later.
1250          */
1251         old_vc_mode = vc_cons[fg_console].d->vc_mode;
1252         switch_screen(vc);
1253
1254         /*
1255          * This can't appear below a successful kill_pid().  If it did,
1256          * then the *blank_screen operation could occur while X, having
1257          * received acqsig, is waking up on another processor.  This
1258          * condition can lead to overlapping accesses to the VGA range
1259          * and the framebuffer (causing system lockups).
1260          *
1261          * To account for this we duplicate this code below only if the
1262          * controlling process is gone and we've called reset_vc.
1263          */
1264         if (old_vc_mode != vc->vc_mode) {
1265                 if (vc->vc_mode == KD_TEXT)
1266                         do_unblank_screen(1);
1267                 else
1268                         do_blank_screen(1);
1269         }
1270
1271         /*
1272          * If this new console is under process control, send it a signal
1273          * telling it that it has acquired. Also check if it has died and
1274          * clean up (similar to logic employed in change_console())
1275          */
1276         if (vc->vt_mode.mode == VT_PROCESS) {
1277                 /*
1278                  * Send the signal as privileged - kill_pid() will
1279                  * tell us if the process has gone or something else
1280                  * is awry
1281                  */
1282                 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1283                 /*
1284                  * The controlling process has died, so we revert back to
1285                  * normal operation. In this case, we'll also change back
1286                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1287                  * but it saves the agony when the X server dies and the screen
1288                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1289                  * this outside of VT_PROCESS but there is no single process
1290                  * to account for and tracking tty count may be undesirable.
1291                  */
1292                         reset_vc(vc);
1293
1294                         if (old_vc_mode != vc->vc_mode) {
1295                                 if (vc->vc_mode == KD_TEXT)
1296                                         do_unblank_screen(1);
1297                                 else
1298                                         do_blank_screen(1);
1299                         }
1300                 }
1301         }
1302
1303         /*
1304          * Wake anyone waiting for their VT to activate
1305          */
1306         vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1307         return;
1308 }
1309
1310 /*
1311  * Performs the front-end of a vt switch
1312  */
1313 void change_console(struct vc_data *new_vc)
1314 {
1315         struct vc_data *vc;
1316
1317         if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1318                 return;
1319
1320         /*
1321          * If this vt is in process mode, then we need to handshake with
1322          * that process before switching. Essentially, we store where that
1323          * vt wants to switch to and wait for it to tell us when it's done
1324          * (via VT_RELDISP ioctl).
1325          *
1326          * We also check to see if the controlling process still exists.
1327          * If it doesn't, we reset this vt to auto mode and continue.
1328          * This is a cheap way to track process control. The worst thing
1329          * that can happen is: we send a signal to a process, it dies, and
1330          * the switch gets "lost" waiting for a response; hopefully, the
1331          * user will try again, we'll detect the process is gone (unless
1332          * the user waits just the right amount of time :-) and revert the
1333          * vt to auto control.
1334          */
1335         vc = vc_cons[fg_console].d;
1336         if (vc->vt_mode.mode == VT_PROCESS) {
1337                 /*
1338                  * Send the signal as privileged - kill_pid() will
1339                  * tell us if the process has gone or something else
1340                  * is awry.
1341                  *
1342                  * We need to set vt_newvt *before* sending the signal or we
1343                  * have a race.
1344                  */
1345                 vc->vt_newvt = new_vc->vc_num;
1346                 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1347                         /*
1348                          * It worked. Mark the vt to switch to and
1349                          * return. The process needs to send us a
1350                          * VT_RELDISP ioctl to complete the switch.
1351                          */
1352                         return;
1353                 }
1354
1355                 /*
1356                  * The controlling process has died, so we revert back to
1357                  * normal operation. In this case, we'll also change back
1358                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1359                  * but it saves the agony when the X server dies and the screen
1360                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1361                  * this outside of VT_PROCESS but there is no single process
1362                  * to account for and tracking tty count may be undesirable.
1363                  */
1364                 reset_vc(vc);
1365
1366                 /*
1367                  * Fall through to normal (VT_AUTO) handling of the switch...
1368                  */
1369         }
1370
1371         /*
1372          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1373          */
1374         if (vc->vc_mode == KD_GRAPHICS)
1375                 return;
1376
1377         complete_change_console(new_vc);
1378 }
1379
1380 /* Perform a kernel triggered VT switch for suspend/resume */
1381
1382 static int disable_vt_switch;
1383
1384 int vt_move_to_console(unsigned int vt, int alloc)
1385 {
1386         int prev;
1387
1388         console_lock();
1389         /* Graphics mode - up to X */
1390         if (disable_vt_switch) {
1391                 console_unlock();
1392                 return 0;
1393         }
1394         prev = fg_console;
1395
1396         if (alloc && vc_allocate(vt)) {
1397                 /* we can't have a free VC for now. Too bad,
1398                  * we don't want to mess the screen for now. */
1399                 console_unlock();
1400                 return -ENOSPC;
1401         }
1402
1403         if (set_console(vt)) {
1404                 /*
1405                  * We're unable to switch to the SUSPEND_CONSOLE.
1406                  * Let the calling function know so it can decide
1407                  * what to do.
1408                  */
1409                 console_unlock();
1410                 return -EIO;
1411         }
1412         console_unlock();
1413         if (vt_waitactive(vt + 1)) {
1414                 pr_debug("Suspend: Can't switch VCs.");
1415                 return -EINTR;
1416         }
1417         return prev;
1418 }
1419
1420 /*
1421  * Normally during a suspend, we allocate a new console and switch to it.
1422  * When we resume, we switch back to the original console.  This switch
1423  * can be slow, so on systems where the framebuffer can handle restoration
1424  * of video registers anyways, there's little point in doing the console
1425  * switch.  This function allows you to disable it by passing it '0'.
1426  */
1427 void pm_set_vt_switch(int do_switch)
1428 {
1429         console_lock();
1430         disable_vt_switch = !do_switch;
1431         console_unlock();
1432 }
1433 EXPORT_SYMBOL(pm_set_vt_switch);