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 static void __vt_event_queue(struct vt_event_wait *vw)
 114 {
 115         unsigned long flags;
 116         /* Prepare the event */
 117         INIT_LIST_HEAD(&vw->list);
 118         vw->done = 0;
 119         /* Queue our event */
 120         spin_lock_irqsave(&vt_event_lock, flags);
 121         list_add(&vw->list, &vt_events);
 122         spin_unlock_irqrestore(&vt_event_lock, flags);
 123 }
 124
 125 static void __vt_event_wait(struct vt_event_wait *vw)
 126 {
 127         /* Wait for it to pass */
 128         wait_event_interruptible(vt_event_waitqueue, vw->done);
 129 }
 130
 131 static void __vt_event_dequeue(struct vt_event_wait *vw)
 132 {
 133         unsigned long flags;
 134
 135         /* Dequeue it */
 136         spin_lock_irqsave(&vt_event_lock, flags);
 137         list_del(&vw->list);
 138         spin_unlock_irqrestore(&vt_event_lock, flags);
 139 }
 140
 141 /**
 142  *      vt_event_wait           -       wait for an event
 143  *      @vw: our event
 144  *
 145  *      Waits for an event to occur which completes our vt_event_wait
 146  *      structure. On return the structure has wv->done set to 1 for success
 147  *      or 0 if some event such as a signal ended the wait.
 148  */
 149
 150 static void vt_event_wait(struct vt_event_wait *vw)
 151 {
 152         __vt_event_queue(vw);
 153         __vt_event_wait(vw);
 154         __vt_event_dequeue(vw);
 155 }
 156
 157 /**
 158  *      vt_event_wait_ioctl     -       event ioctl handler
 159  *      @arg: argument to ioctl
 160  *
 161  *      Implement the VT_WAITEVENT ioctl using the VT event interface
 162  */
 163
 164 static int vt_event_wait_ioctl(struct vt_event __user *event)
 165 {
 166         struct vt_event_wait vw;
 167
 168         if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
 169                 return -EFAULT;
 170         /* Highest supported event for now */
 171         if (vw.event.event & ~VT_MAX_EVENT)
 172                 return -EINVAL;
 173
 174         vt_event_wait(&vw);
 175         /* If it occurred report it */
 176         if (vw.done) {
 177                 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
 178                         return -EFAULT;
 179                 return 0;
 180         }
 181         return -EINTR;
 182 }
 183
 184 /**
 185  *      vt_waitactive   -       active console wait
 186  *      @event: event code
 187  *      @n: new console
 188  *
 189  *      Helper for event waits. Used to implement the legacy
 190  *      event waiting ioctls in terms of events
 191  */
 192
 193 int vt_waitactive(int n)
 194 {
 195         struct vt_event_wait vw;
 196         do {
 197                 vw.event.event = VT_EVENT_SWITCH;
 198                 __vt_event_queue(&vw);
 199                 if (n == fg_console + 1) {
 200                         __vt_event_dequeue(&vw);
 201                         break;
 202                 }
 203                 __vt_event_wait(&vw);
 204                 __vt_event_dequeue(&vw);
 205                 if (vw.done == 0)
 206                         return -EINTR;
 207         } while (vw.event.newev != n);
 208         return 0;
 209 }
 210
 211 /*
 212  * these are the valid i/o ports we're allowed to change. they map all the
 213  * video ports
 214  */
 215 #define GPFIRST 0x3b4
 216 #define GPLAST 0x3df
 217 #define GPNUM (GPLAST - GPFIRST + 1)
 218
 219
 220
 221 static inline int
 222 do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
 223 {
 224         struct consolefontdesc cfdarg;
 225         int i;
 226
 227         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
 228                 return -EFAULT;
 229
 230         switch (cmd) {
 231         case PIO_FONTX:
 232                 if (!perm)
 233                         return -EPERM;
 234                 op->op = KD_FONT_OP_SET;
 235                 op->flags = KD_FONT_FLAG_OLD;
 236                 op->width = 8;
 237                 op->height = cfdarg.charheight;
 238                 op->charcount = cfdarg.charcount;
 239                 op->data = cfdarg.chardata;
 240                 return con_font_op(vc_cons[fg_console].d, op);
 241         case GIO_FONTX: {
 242                 op->op = KD_FONT_OP_GET;
 243                 op->flags = KD_FONT_FLAG_OLD;
 244                 op->width = 8;
 245                 op->height = cfdarg.charheight;
 246                 op->charcount = cfdarg.charcount;
 247                 op->data = cfdarg.chardata;
 248                 i = con_font_op(vc_cons[fg_console].d, op);
 249                 if (i)
 250                         return i;
 251                 cfdarg.charheight = op->height;
 252                 cfdarg.charcount = op->charcount;
 253                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
 254                         return -EFAULT;
 255                 return 0;
 256                 }
 257         }
 258         return -EINVAL;
 259 }
 260
 261 static inline int
 262 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
 263 {
 264         struct unimapdesc tmp;
 265
 266         if (copy_from_user(&tmp, user_ud, sizeof tmp))
 267                 return -EFAULT;
 268         if (tmp.entries)
 269                 if (!access_ok(VERIFY_WRITE, tmp.entries,
 270                                 tmp.entry_ct*sizeof(struct unipair)))
 271                         return -EFAULT;
 272         switch (cmd) {
 273         case PIO_UNIMAP:
 274                 if (!perm)
 275                         return -EPERM;
 276                 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
 277         case GIO_UNIMAP:
 278                 if (!perm && fg_console != vc->vc_num)
 279                         return -EPERM;
 280                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
 281         }
 282         return 0;
 283 }
 284
 285
 286
 287 /*
 288  * We handle the console-specific ioctl's here.  We allow the
 289  * capability to modify any console, not just the fg_console.
 290  */
 291 int vt_ioctl(struct tty_struct *tty,
 292              unsigned int cmd, unsigned long arg)
 293 {
 294         struct vc_data *vc = tty->driver_data;
 295         struct console_font_op op;      /* used in multiple places here */
 296         unsigned int console;
 297         unsigned char ucval;
 298         unsigned int uival;
 299         void __user *up = (void __user *)arg;
 300         int i, perm;
 301         int ret = 0;
 302
 303         console = vc->vc_num;
 304
 305
 306         if (!vc_cons_allocated(console)) {      /* impossible? */
 307                 ret = -ENOIOCTLCMD;
 308                 goto out;
 309         }
 310
 311
 312         /*
 313          * To have permissions to do most of the vt ioctls, we either have
 314          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
 315          */
 316         perm = 0;
 317         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
 318                 perm = 1;
 319
 320         switch (cmd) {
 321         case TIOCLINUX:
 322                 ret = tioclinux(tty, arg);
 323                 break;
 324         case KIOCSOUND:
 325                 if (!perm)
 326                         return -EPERM;
 327                 /*
 328                  * The use of PIT_TICK_RATE is historic, it used to be
 329                  * the platform-dependent CLOCK_TICK_RATE between 2.6.12
 330                  * and 2.6.36, which was a minor but unfortunate ABI
 331                  * change. kd_mksound is locked by the input layer.
 332                  */
 333                 if (arg)
 334                         arg = PIT_TICK_RATE / arg;
 335                 kd_mksound(arg, 0);
 336                 break;
 337
 338         case KDMKTONE:
 339                 if (!perm)
 340                         return -EPERM;
 341         {
 342                 unsigned int ticks, count;
 343
 344                 /*
 345                  * Generate the tone for the appropriate number of ticks.
 346                  * If the time is zero, turn off sound ourselves.
 347                  */
 348                 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
 349                 count = ticks ? (arg & 0xffff) : 0;
 350                 if (count)
 351                         count = PIT_TICK_RATE / count;
 352                 kd_mksound(count, ticks);
 353                 break;
 354         }
 355
 356         case KDGKBTYPE:
 357                 /*
 358                  * this is naïve.
 359                  */
 360                 ucval = KB_101;
 361                 ret = put_user(ucval, (char __user *)arg);
 362                 break;
 363
 364                 /*
 365                  * These cannot be implemented on any machine that implements
 366                  * ioperm() in user level (such as Alpha PCs) or not at all.
 367                  *
 368                  * XXX: you should never use these, just call ioperm directly..
 369                  */
 370 #ifdef CONFIG_X86
 371         case KDADDIO:
 372         case KDDELIO:
 373                 /*
 374                  * KDADDIO and KDDELIO may be able to add ports beyond what
 375                  * we reject here, but to be safe...
 376                  *
 377                  * These are locked internally via sys_ioperm
 378                  */
 379                 if (arg < GPFIRST || arg > GPLAST) {
 380                         ret = -EINVAL;
 381                         break;
 382                 }
 383                 ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 384                 break;
 385
 386         case KDENABIO:
 387         case KDDISABIO:
 388                 ret = sys_ioperm(GPFIRST, GPNUM,
 389                                   (cmd == KDENABIO)) ? -ENXIO : 0;
 390                 break;
 391 #endif
 392
 393         /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
 394
 395         case KDKBDREP:
 396         {
 397                 struct kbd_repeat kbrep;
 398
 399                 if (!capable(CAP_SYS_TTY_CONFIG))
 400                         return -EPERM;
 401
 402                 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
 403                         ret =  -EFAULT;
 404                         break;
 405                 }
 406                 ret = kbd_rate(&kbrep);
 407                 if (ret)
 408                         break;
 409                 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
 410                         ret = -EFAULT;
 411                 break;
 412         }
 413
 414         case KDSETMODE:
 415                 /*
 416                  * currently, setting the mode from KD_TEXT to KD_GRAPHICS
 417                  * doesn't do a whole lot. i'm not sure if it should do any
 418                  * restoration of modes or what...
 419                  *
 420                  * XXX It should at least call into the driver, fbdev's definitely
 421                  * need to restore their engine state. --BenH
 422                  */
 423                 if (!perm)
 424                         return -EPERM;
 425                 switch (arg) {
 426                 case KD_GRAPHICS:
 427                         break;
 428                 case KD_TEXT0:
 429                 case KD_TEXT1:
 430                         arg = KD_TEXT;
 431                 case KD_TEXT:
 432                         break;
 433                 default:
 434                         ret = -EINVAL;
 435                         goto out;
 436                 }
 437                 /* FIXME: this needs the console lock extending */
 438                 if (vc->vc_mode == (unsigned char) arg)
 439                         break;
 440                 vc->vc_mode = (unsigned char) arg;
 441                 if (console != fg_console)
 442                         break;
 443                 /*
 444                  * explicitly blank/unblank the screen if switching modes
 445                  */
 446                 console_lock();
 447                 if (arg == KD_TEXT)
 448                         do_unblank_screen(1);
 449                 else
 450                         do_blank_screen(1);
 451                 console_unlock();
 452                 break;
 453
 454         case KDGETMODE:
 455                 uival = vc->vc_mode;
 456                 goto setint;
 457
 458         case KDMAPDISP:
 459         case KDUNMAPDISP:
 460                 /*
 461                  * these work like a combination of mmap and KDENABIO.
 462                  * this could be easily finished.
 463                  */
 464                 ret = -EINVAL;
 465                 break;
 466
 467         case KDSKBMODE:
 468                 if (!perm)
 469                         return -EPERM;
 470                 ret = vt_do_kdskbmode(console, arg);
 471                 if (ret == 0)
 472                         tty_ldisc_flush(tty);
 473                 break;
 474
 475         case KDGKBMODE:
 476                 uival = vt_do_kdgkbmode(console);
 477                 ret = put_user(uival, (int __user *)arg);
 478                 break;
 479
 480         /* this could be folded into KDSKBMODE, but for compatibility
 481            reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 482         case KDSKBMETA:
 483                 ret = vt_do_kdskbmeta(console, arg);
 484                 break;
 485
 486         case KDGKBMETA:
 487                 /* FIXME: should review whether this is worth locking */
 488                 uival = vt_do_kdgkbmeta(console);
 489         setint:
 490                 ret = put_user(uival, (int __user *)arg);
 491                 break;
 492
 493         case KDGETKEYCODE:
 494         case KDSETKEYCODE:
 495                 if(!capable(CAP_SYS_TTY_CONFIG))
 496                         perm = 0;
 497                 ret = vt_do_kbkeycode_ioctl(cmd, up, perm);
 498                 break;
 499
 500         case KDGKBENT:
 501         case KDSKBENT:
 502                 ret = vt_do_kdsk_ioctl(cmd, up, perm, console);
 503                 break;
 504
 505         case KDGKBSENT:
 506         case KDSKBSENT:
 507                 ret = vt_do_kdgkb_ioctl(cmd, up, perm);
 508                 break;
 509
 510         /* Diacritical processing. Handled in keyboard.c as it has
 511            to operate on the keyboard locks and structures */
 512         case KDGKBDIACR:
 513         case KDGKBDIACRUC:
 514         case KDSKBDIACR:
 515         case KDSKBDIACRUC:
 516                 ret = vt_do_diacrit(cmd, up, perm);
 517                 break;
 518
 519         /* the ioctls below read/set the flags usually shown in the leds */
 520         /* don't use them - they will go away without warning */
 521         case KDGKBLED:
 522         case KDSKBLED:
 523         case KDGETLED:
 524         case KDSETLED:
 525                 ret = vt_do_kdskled(console, cmd, arg, perm);
 526                 break;
 527
 528         /*
 529          * A process can indicate its willingness to accept signals
 530          * generated by pressing an appropriate key combination.
 531          * Thus, one can have a daemon that e.g. spawns a new console
 532          * upon a keypress and then changes to it.
 533          * See also the kbrequest field of inittab(5).
 534          */
 535         case KDSIGACCEPT:
 536         {
 537                 if (!perm || !capable(CAP_KILL))
 538                         return -EPERM;
 539                 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
 540                         ret = -EINVAL;
 541                 else {
 542                         spin_lock_irq(&vt_spawn_con.lock);
 543                         put_pid(vt_spawn_con.pid);
 544                         vt_spawn_con.pid = get_pid(task_pid(current));
 545                         vt_spawn_con.sig = arg;
 546                         spin_unlock_irq(&vt_spawn_con.lock);
 547                 }
 548                 break;
 549         }
 550
 551         case VT_SETMODE:
 552         {
 553                 struct vt_mode tmp;
 554
 555                 if (!perm)
 556                         return -EPERM;
 557                 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
 558                         ret = -EFAULT;
 559                         goto out;
 560                 }
 561                 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
 562                         ret = -EINVAL;
 563                         goto out;
 564                 }
 565                 console_lock();
 566                 vc->vt_mode = tmp;
 567                 /* the frsig is ignored, so we set it to 0 */
 568                 vc->vt_mode.frsig = 0;
 569                 put_pid(vc->vt_pid);
 570                 vc->vt_pid = get_pid(task_pid(current));
 571                 /* no switch is required -- saw@shade.msu.ru */
 572                 vc->vt_newvt = -1;
 573                 console_unlock();
 574                 break;
 575         }
 576
 577         case VT_GETMODE:
 578         {
 579                 struct vt_mode tmp;
 580                 int rc;
 581
 582                 console_lock();
 583                 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
 584                 console_unlock();
 585
 586                 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
 587                 if (rc)
 588                         ret = -EFAULT;
 589                 break;
 590         }
 591
 592         /*
 593          * Returns global vt state. Note that VT 0 is always open, since
 594          * it's an alias for the current VT, and people can't use it here.
 595          * We cannot return state for more than 16 VTs, since v_state is short.
 596          */
 597         case VT_GETSTATE:
 598         {
 599                 struct vt_stat __user *vtstat = up;
 600                 unsigned short state, mask;
 601
 602                 /* Review: FIXME: Console lock ? */
 603                 if (put_user(fg_console + 1, &vtstat->v_active))
 604                         ret = -EFAULT;
 605                 else {
 606                         state = 1;      /* /dev/tty0 is always open */
 607                         for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
 608                                                         ++i, mask <<= 1)
 609                                 if (VT_IS_IN_USE(i))
 610                                         state |= mask;
 611                         ret = put_user(state, &vtstat->v_state);
 612                 }
 613                 break;
 614         }
 615
 616         /*
 617          * Returns the first available (non-opened) console.
 618          */
 619         case VT_OPENQRY:
 620                 /* FIXME: locking ? - but then this is a stupid API */
 621                 for (i = 0; i < MAX_NR_CONSOLES; ++i)
 622                         if (! VT_IS_IN_USE(i))
 623                                 break;
 624                 uival = i < MAX_NR_CONSOLES ? (i+1) : -1;
 625                 goto setint;
 626
 627         /*
 628          * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
 629          * with num >= 1 (switches to vt 0, our console, are not allowed, just
 630          * to preserve sanity).
 631          */
 632         case VT_ACTIVATE:
 633                 if (!perm)
 634                         return -EPERM;
 635                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 636                         ret =  -ENXIO;
 637                 else {
 638                         arg--;
 639                         console_lock();
 640                         ret = vc_allocate(arg);
 641                         console_unlock();
 642                         if (ret)
 643                                 break;
 644                         set_console(arg);
 645                 }
 646                 break;
 647
 648         case VT_SETACTIVATE:
 649         {
 650                 struct vt_setactivate vsa;
 651
 652                 if (!perm)
 653                         return -EPERM;
 654
 655                 if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,
 656                                         sizeof(struct vt_setactivate))) {
 657                         ret = -EFAULT;
 658                         goto out;
 659                 }
 660                 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
 661                         ret = -ENXIO;
 662                 else {
 663                         vsa.console--;
 664                         console_lock();
 665                         ret = vc_allocate(vsa.console);
 666                         if (ret == 0) {
 667                                 struct vc_data *nvc;
 668                                 /* This is safe providing we don't drop the
 669                                    console sem between vc_allocate and
 670                                    finishing referencing nvc */
 671                                 nvc = vc_cons[vsa.console].d;
 672                                 nvc->vt_mode = vsa.mode;
 673                                 nvc->vt_mode.frsig = 0;
 674                                 put_pid(nvc->vt_pid);
 675                                 nvc->vt_pid = get_pid(task_pid(current));
 676                         }
 677                         console_unlock();
 678                         if (ret)
 679                                 break;
 680                         /* Commence switch and lock */
 681                         /* Review set_console locks */
 682                         set_console(vsa.console);
 683                 }
 684                 break;
 685         }
 686
 687         /*
 688          * wait until the specified VT has been activated
 689          */
 690         case VT_WAITACTIVE:
 691                 if (!perm)
 692                         return -EPERM;
 693                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 694                         ret = -ENXIO;
 695                 else
 696                         ret = vt_waitactive(arg);
 697                 break;
 698
 699         /*
 700          * If a vt is under process control, the kernel will not switch to it
 701          * immediately, but postpone the operation until the process calls this
 702          * ioctl, allowing the switch to complete.
 703          *
 704          * According to the X sources this is the behavior:
 705          *      0:      pending switch-from not OK
 706          *      1:      pending switch-from OK
 707          *      2:      completed switch-to OK
 708          */
 709         case VT_RELDISP:
 710                 if (!perm)
 711                         return -EPERM;
 712
 713                 console_lock();
 714                 if (vc->vt_mode.mode != VT_PROCESS) {
 715                         console_unlock();
 716                         ret = -EINVAL;
 717                         break;
 718                 }
 719                 /*
 720                  * Switching-from response
 721                  */
 722                 if (vc->vt_newvt >= 0) {
 723                         if (arg == 0)
 724                                 /*
 725                                  * Switch disallowed, so forget we were trying
 726                                  * to do it.
 727                                  */
 728                                 vc->vt_newvt = -1;
 729
 730                         else {
 731                                 /*
 732                                  * The current vt has been released, so
 733                                  * complete the switch.
 734                                  */
 735                                 int newvt;
 736                                 newvt = vc->vt_newvt;
 737                                 vc->vt_newvt = -1;
 738                                 ret = vc_allocate(newvt);
 739                                 if (ret) {
 740                                         console_unlock();
 741                                         break;
 742                                 }
 743                                 /*
 744                                  * When we actually do the console switch,
 745                                  * make sure we are atomic with respect to
 746                                  * other console switches..
 747                                  */
 748                                 complete_change_console(vc_cons[newvt].d);
 749                         }
 750                 } else {
 751                         /*
 752                          * Switched-to response
 753                          */
 754                         /*
 755                          * If it's just an ACK, ignore it
 756                          */
 757                         if (arg != VT_ACKACQ)
 758                                 ret = -EINVAL;
 759                 }
 760                 console_unlock();
 761                 break;
 762
 763          /*
 764           * Disallocate memory associated to VT (but leave VT1)
 765           */
 766          case VT_DISALLOCATE:
 767                 if (arg > MAX_NR_CONSOLES) {
 768                         ret = -ENXIO;
 769                         break;
 770                 }
 771                 if (arg == 0) {
 772                     /* deallocate all unused consoles, but leave 0 */
 773                         console_lock();
 774                         for (i=1; i<MAX_NR_CONSOLES; i++)
 775                                 if (! VT_BUSY(i))
 776                                         vc_deallocate(i);
 777                         console_unlock();
 778                 } else {
 779                         /* deallocate a single console, if possible */
 780                         arg--;
 781                         if (VT_BUSY(arg))
 782                                 ret = -EBUSY;
 783                         else if (arg) {                       /* leave 0 */
 784                                 console_lock();
 785                                 vc_deallocate(arg);
 786                                 console_unlock();
 787                         }
 788                 }
 789                 break;
 790
 791         case VT_RESIZE:
 792         {
 793                 struct vt_sizes __user *vtsizes = up;
 794                 struct vc_data *vc;
 795
 796                 ushort ll,cc;
 797                 if (!perm)
 798                         return -EPERM;
 799                 if (get_user(ll, &vtsizes->v_rows) ||
 800                     get_user(cc, &vtsizes->v_cols))
 801                         ret = -EFAULT;
 802                 else {
 803                         console_lock();
 804                         for (i = 0; i < MAX_NR_CONSOLES; i++) {
 805                                 vc = vc_cons[i].d;
 806
 807                                 if (vc) {
 808                                         vc->vc_resize_user = 1;
 809                                         /* FIXME: review v tty lock */
 810                                         vc_resize(vc_cons[i].d, cc, ll);
 811                                 }
 812                         }
 813                         console_unlock();
 814                 }
 815                 break;
 816         }
 817
 818         case VT_RESIZEX:
 819         {
 820                 struct vt_consize __user *vtconsize = up;
 821                 ushort ll,cc,vlin,clin,vcol,ccol;
 822                 if (!perm)
 823                         return -EPERM;
 824                 if (!access_ok(VERIFY_READ, vtconsize,
 825                                 sizeof(struct vt_consize))) {
 826                         ret = -EFAULT;
 827                         break;
 828                 }
 829                 /* FIXME: Should check the copies properly */
 830                 __get_user(ll, &vtconsize->v_rows);
 831                 __get_user(cc, &vtconsize->v_cols);
 832                 __get_user(vlin, &vtconsize->v_vlin);
 833                 __get_user(clin, &vtconsize->v_clin);
 834                 __get_user(vcol, &vtconsize->v_vcol);
 835                 __get_user(ccol, &vtconsize->v_ccol);
 836                 vlin = vlin ? vlin : vc->vc_scan_lines;
 837                 if (clin) {
 838                         if (ll) {
 839                                 if (ll != vlin/clin) {
 840                                         /* Parameters don't add up */
 841                                         ret = -EINVAL;
 842                                         break;
 843                                 }
 844                         } else
 845                                 ll = vlin/clin;
 846                 }
 847                 if (vcol && ccol) {
 848                         if (cc) {
 849                                 if (cc != vcol/ccol) {
 850                                         ret = -EINVAL;
 851                                         break;
 852                                 }
 853                         } else
 854                                 cc = vcol/ccol;
 855                 }
 856
 857                 if (clin > 32) {
 858                         ret =  -EINVAL;
 859                         break;
 860                 }
 861
 862                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 863                         if (!vc_cons[i].d)
 864                                 continue;
 865                         console_lock();
 866                         if (vlin)
 867                                 vc_cons[i].d->vc_scan_lines = vlin;
 868                         if (clin)
 869                                 vc_cons[i].d->vc_font.height = clin;
 870                         vc_cons[i].d->vc_resize_user = 1;
 871                         vc_resize(vc_cons[i].d, cc, ll);
 872                         console_unlock();
 873                 }
 874                 break;
 875         }
 876
 877         case PIO_FONT: {
 878                 if (!perm)
 879                         return -EPERM;
 880                 op.op = KD_FONT_OP_SET;
 881                 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
 882                 op.width = 8;
 883                 op.height = 0;
 884                 op.charcount = 256;
 885                 op.data = up;
 886                 ret = con_font_op(vc_cons[fg_console].d, &op);
 887                 break;
 888         }
 889
 890         case GIO_FONT: {
 891                 op.op = KD_FONT_OP_GET;
 892                 op.flags = KD_FONT_FLAG_OLD;
 893                 op.width = 8;
 894                 op.height = 32;
 895                 op.charcount = 256;
 896                 op.data = up;
 897                 ret = con_font_op(vc_cons[fg_console].d, &op);
 898                 break;
 899         }
 900
 901         case PIO_CMAP:
 902                 if (!perm)
 903                         ret = -EPERM;
 904                 else
 905                         ret = con_set_cmap(up);
 906                 break;
 907
 908         case GIO_CMAP:
 909                 ret = con_get_cmap(up);
 910                 break;
 911
 912         case PIO_FONTX:
 913         case GIO_FONTX:
 914                 ret = do_fontx_ioctl(cmd, up, perm, &op);
 915                 break;
 916
 917         case PIO_FONTRESET:
 918         {
 919                 if (!perm)
 920                         return -EPERM;
 921
 922 #ifdef BROKEN_GRAPHICS_PROGRAMS
 923                 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
 924                    font is not saved. */
 925                 ret = -ENOSYS;
 926                 break;
 927 #else
 928                 {
 929                 op.op = KD_FONT_OP_SET_DEFAULT;
 930                 op.data = NULL;
 931                 ret = con_font_op(vc_cons[fg_console].d, &op);
 932                 if (ret)
 933                         break;
 934                 console_lock();
 935                 con_set_default_unimap(vc_cons[fg_console].d);
 936                 console_unlock();
 937                 break;
 938                 }
 939 #endif
 940         }
 941
 942         case KDFONTOP: {
 943                 if (copy_from_user(&op, up, sizeof(op))) {
 944                         ret = -EFAULT;
 945                         break;
 946                 }
 947                 if (!perm && op.op != KD_FONT_OP_GET)
 948                         return -EPERM;
 949                 ret = con_font_op(vc, &op);
 950                 if (ret)
 951                         break;
 952                 if (copy_to_user(up, &op, sizeof(op)))
 953                         ret = -EFAULT;
 954                 break;
 955         }
 956
 957         case PIO_SCRNMAP:
 958                 if (!perm)
 959                         ret = -EPERM;
 960                 else
 961                         ret = con_set_trans_old(up);
 962                 break;
 963
 964         case GIO_SCRNMAP:
 965                 ret = con_get_trans_old(up);
 966                 break;
 967
 968         case PIO_UNISCRNMAP:
 969                 if (!perm)
 970                         ret = -EPERM;
 971                 else
 972                         ret = con_set_trans_new(up);
 973                 break;
 974
 975         case GIO_UNISCRNMAP:
 976                 ret = con_get_trans_new(up);
 977                 break;
 978
 979         case PIO_UNIMAPCLR:
 980               { struct unimapinit ui;
 981                 if (!perm)
 982                         return -EPERM;
 983                 ret = copy_from_user(&ui, up, sizeof(struct unimapinit));
 984                 if (ret)
 985                         ret = -EFAULT;
 986                 else
 987                         con_clear_unimap(vc, &ui);
 988                 break;
 989               }
 990
 991         case PIO_UNIMAP:
 992         case GIO_UNIMAP:
 993                 ret = do_unimap_ioctl(cmd, up, perm, vc);
 994                 break;
 995
 996         case VT_LOCKSWITCH:
 997                 if (!capable(CAP_SYS_TTY_CONFIG))
 998                         return -EPERM;
 999                 vt_dont_switch = 1;
1000                 break;
1001         case VT_UNLOCKSWITCH:
1002                 if (!capable(CAP_SYS_TTY_CONFIG))
1003                         return -EPERM;
1004                 vt_dont_switch = 0;
1005                 break;
1006         case VT_GETHIFONTMASK:
1007                 ret = put_user(vc->vc_hi_font_mask,
1008                                         (unsigned short __user *)arg);
1009                 break;
1010         case VT_WAITEVENT:
1011                 ret = vt_event_wait_ioctl((struct vt_event __user *)arg);
1012                 break;
1013         default:
1014                 ret = -ENOIOCTLCMD;
1015         }
1016 out:
1017         return ret;
1018 }
1019
1020 void reset_vc(struct vc_data *vc)
1021 {
1022         vc->vc_mode = KD_TEXT;
1023         vt_reset_unicode(vc->vc_num);
1024         vc->vt_mode.mode = VT_AUTO;
1025         vc->vt_mode.waitv = 0;
1026         vc->vt_mode.relsig = 0;
1027         vc->vt_mode.acqsig = 0;
1028         vc->vt_mode.frsig = 0;
1029         put_pid(vc->vt_pid);
1030         vc->vt_pid = NULL;
1031         vc->vt_newvt = -1;
1032         if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
1033                 reset_palette(vc);
1034 }
1035
1036 void vc_SAK(struct work_struct *work)
1037 {
1038         struct vc *vc_con =
1039                 container_of(work, struct vc, SAK_work);
1040         struct vc_data *vc;
1041         struct tty_struct *tty;
1042
1043         console_lock();
1044         vc = vc_con->d;
1045         if (vc) {
1046                 /* FIXME: review tty ref counting */
1047                 tty = vc->port.tty;
1048                 /*
1049                  * SAK should also work in all raw modes and reset
1050                  * them properly.
1051                  */
1052                 if (tty)
1053                         __do_SAK(tty);
1054                 reset_vc(vc);
1055         }
1056         console_unlock();
1057 }
1058
1059 #ifdef CONFIG_COMPAT
1060
1061 struct compat_consolefontdesc {
1062         unsigned short charcount;       /* characters in font (256 or 512) */
1063         unsigned short charheight;      /* scan lines per character (1-32) */
1064         compat_caddr_t chardata;        /* font data in expanded form */
1065 };
1066
1067 static inline int
1068 compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
1069                          int perm, struct console_font_op *op)
1070 {
1071         struct compat_consolefontdesc cfdarg;
1072         int i;
1073
1074         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1075                 return -EFAULT;
1076
1077         switch (cmd) {
1078         case PIO_FONTX:
1079                 if (!perm)
1080                         return -EPERM;
1081                 op->op = KD_FONT_OP_SET;
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                 return con_font_op(vc_cons[fg_console].d, op);
1088         case GIO_FONTX:
1089                 op->op = KD_FONT_OP_GET;
1090                 op->flags = KD_FONT_FLAG_OLD;
1091                 op->width = 8;
1092                 op->height = cfdarg.charheight;
1093                 op->charcount = cfdarg.charcount;
1094                 op->data = compat_ptr(cfdarg.chardata);
1095                 i = con_font_op(vc_cons[fg_console].d, op);
1096                 if (i)
1097                         return i;
1098                 cfdarg.charheight = op->height;
1099                 cfdarg.charcount = op->charcount;
1100                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1101                         return -EFAULT;
1102                 return 0;
1103         }
1104         return -EINVAL;
1105 }
1106
1107 struct compat_console_font_op {
1108         compat_uint_t op;        /* operation code KD_FONT_OP_* */
1109         compat_uint_t flags;     /* KD_FONT_FLAG_* */
1110         compat_uint_t width, height;     /* font size */
1111         compat_uint_t charcount;
1112         compat_caddr_t data;    /* font data with height fixed to 32 */
1113 };
1114
1115 static inline int
1116 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1117                          int perm, struct console_font_op *op, struct vc_data *vc)
1118 {
1119         int i;
1120
1121         if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1122                 return -EFAULT;
1123         if (!perm && op->op != KD_FONT_OP_GET)
1124                 return -EPERM;
1125         op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1126         i = con_font_op(vc, op);
1127         if (i)
1128                 return i;
1129         ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1130         if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1131                 return -EFAULT;
1132         return 0;
1133 }
1134
1135 struct compat_unimapdesc {
1136         unsigned short entry_ct;
1137         compat_caddr_t entries;
1138 };
1139
1140 static inline int
1141 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1142                          int perm, struct vc_data *vc)
1143 {
1144         struct compat_unimapdesc tmp;
1145         struct unipair __user *tmp_entries;
1146
1147         if (copy_from_user(&tmp, user_ud, sizeof tmp))
1148                 return -EFAULT;
1149         tmp_entries = compat_ptr(tmp.entries);
1150         if (tmp_entries)
1151                 if (!access_ok(VERIFY_WRITE, tmp_entries,
1152                                 tmp.entry_ct*sizeof(struct unipair)))
1153                         return -EFAULT;
1154         switch (cmd) {
1155         case PIO_UNIMAP:
1156                 if (!perm)
1157                         return -EPERM;
1158                 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1159         case GIO_UNIMAP:
1160                 if (!perm && fg_console != vc->vc_num)
1161                         return -EPERM;
1162                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1163         }
1164         return 0;
1165 }
1166
1167 long vt_compat_ioctl(struct tty_struct *tty,
1168              unsigned int cmd, unsigned long arg)
1169 {
1170         struct vc_data *vc = tty->driver_data;
1171         struct console_font_op op;      /* used in multiple places here */
1172         unsigned int console;
1173         void __user *up = (void __user *)arg;
1174         int perm;
1175         int ret = 0;
1176
1177         console = vc->vc_num;
1178
1179         if (!vc_cons_allocated(console)) {      /* impossible? */
1180                 ret = -ENOIOCTLCMD;
1181                 goto out;
1182         }
1183
1184         /*
1185          * To have permissions to do most of the vt ioctls, we either have
1186          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1187          */
1188         perm = 0;
1189         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1190                 perm = 1;
1191
1192         switch (cmd) {
1193         /*
1194          * these need special handlers for incompatible data structures
1195          */
1196         case PIO_FONTX:
1197         case GIO_FONTX:
1198                 ret = compat_fontx_ioctl(cmd, up, perm, &op);
1199                 break;
1200
1201         case KDFONTOP:
1202                 ret = compat_kdfontop_ioctl(up, perm, &op, vc);
1203                 break;
1204
1205         case PIO_UNIMAP:
1206         case GIO_UNIMAP:
1207                 ret = compat_unimap_ioctl(cmd, up, perm, vc);
1208                 break;
1209
1210         /*
1211          * all these treat 'arg' as an integer
1212          */
1213         case KIOCSOUND:
1214         case KDMKTONE:
1215 #ifdef CONFIG_X86
1216         case KDADDIO:
1217         case KDDELIO:
1218 #endif
1219         case KDSETMODE:
1220         case KDMAPDISP:
1221         case KDUNMAPDISP:
1222         case KDSKBMODE:
1223         case KDSKBMETA:
1224         case KDSKBLED:
1225         case KDSETLED:
1226         case KDSIGACCEPT:
1227         case VT_ACTIVATE:
1228         case VT_WAITACTIVE:
1229         case VT_RELDISP:
1230         case VT_DISALLOCATE:
1231         case VT_RESIZE:
1232         case VT_RESIZEX:
1233                 goto fallback;
1234
1235         /*
1236          * the rest has a compatible data structure behind arg,
1237          * but we have to convert it to a proper 64 bit pointer.
1238          */
1239         default:
1240                 arg = (unsigned long)compat_ptr(arg);
1241                 goto fallback;
1242         }
1243 out:
1244         return ret;
1245
1246 fallback:
1247         return vt_ioctl(tty, cmd, arg);
1248 }
1249
1250
1251 #endif /* CONFIG_COMPAT */
1252
1253
1254 /*
1255  * Performs the back end of a vt switch. Called under the console
1256  * semaphore.
1257  */
1258 static void complete_change_console(struct vc_data *vc)
1259 {
1260         unsigned char old_vc_mode;
1261         int old = fg_console;
1262
1263         last_console = fg_console;
1264
1265         /*
1266          * If we're switching, we could be going from KD_GRAPHICS to
1267          * KD_TEXT mode or vice versa, which means we need to blank or
1268          * unblank the screen later.
1269          */
1270         old_vc_mode = vc_cons[fg_console].d->vc_mode;
1271         switch_screen(vc);
1272
1273         /*
1274          * This can't appear below a successful kill_pid().  If it did,
1275          * then the *blank_screen operation could occur while X, having
1276          * received acqsig, is waking up on another processor.  This
1277          * condition can lead to overlapping accesses to the VGA range
1278          * and the framebuffer (causing system lockups).
1279          *
1280          * To account for this we duplicate this code below only if the
1281          * controlling process is gone and we've called reset_vc.
1282          */
1283         if (old_vc_mode != vc->vc_mode) {
1284                 if (vc->vc_mode == KD_TEXT)
1285                         do_unblank_screen(1);
1286                 else
1287                         do_blank_screen(1);
1288         }
1289
1290         /*
1291          * If this new console is under process control, send it a signal
1292          * telling it that it has acquired. Also check if it has died and
1293          * clean up (similar to logic employed in change_console())
1294          */
1295         if (vc->vt_mode.mode == VT_PROCESS) {
1296                 /*
1297                  * Send the signal as privileged - kill_pid() will
1298                  * tell us if the process has gone or something else
1299                  * is awry
1300                  */
1301                 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1302                 /*
1303                  * The controlling process has died, so we revert back to
1304                  * normal operation. In this case, we'll also change back
1305                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1306                  * but it saves the agony when the X server dies and the screen
1307                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1308                  * this outside of VT_PROCESS but there is no single process
1309                  * to account for and tracking tty count may be undesirable.
1310                  */
1311                         reset_vc(vc);
1312
1313                         if (old_vc_mode != vc->vc_mode) {
1314                                 if (vc->vc_mode == KD_TEXT)
1315                                         do_unblank_screen(1);
1316                                 else
1317                                         do_blank_screen(1);
1318                         }
1319                 }
1320         }
1321
1322         /*
1323          * Wake anyone waiting for their VT to activate
1324          */
1325         vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1326         return;
1327 }
1328
1329 /*
1330  * Performs the front-end of a vt switch
1331  */
1332 void change_console(struct vc_data *new_vc)
1333 {
1334         struct vc_data *vc;
1335
1336         if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1337                 return;
1338
1339         /*
1340          * If this vt is in process mode, then we need to handshake with
1341          * that process before switching. Essentially, we store where that
1342          * vt wants to switch to and wait for it to tell us when it's done
1343          * (via VT_RELDISP ioctl).
1344          *
1345          * We also check to see if the controlling process still exists.
1346          * If it doesn't, we reset this vt to auto mode and continue.
1347          * This is a cheap way to track process control. The worst thing
1348          * that can happen is: we send a signal to a process, it dies, and
1349          * the switch gets "lost" waiting for a response; hopefully, the
1350          * user will try again, we'll detect the process is gone (unless
1351          * the user waits just the right amount of time :-) and revert the
1352          * vt to auto control.
1353          */
1354         vc = vc_cons[fg_console].d;
1355         if (vc->vt_mode.mode == VT_PROCESS) {
1356                 /*
1357                  * Send the signal as privileged - kill_pid() will
1358                  * tell us if the process has gone or something else
1359                  * is awry.
1360                  *
1361                  * We need to set vt_newvt *before* sending the signal or we
1362                  * have a race.
1363                  */
1364                 vc->vt_newvt = new_vc->vc_num;
1365                 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1366                         /*
1367                          * It worked. Mark the vt to switch to and
1368                          * return. The process needs to send us a
1369                          * VT_RELDISP ioctl to complete the switch.
1370                          */
1371                         return;
1372                 }
1373
1374                 /*
1375                  * The controlling process has died, so we revert back to
1376                  * normal operation. In this case, we'll also change back
1377                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1378                  * but it saves the agony when the X server dies and the screen
1379                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1380                  * this outside of VT_PROCESS but there is no single process
1381                  * to account for and tracking tty count may be undesirable.
1382                  */
1383                 reset_vc(vc);
1384
1385                 /*
1386                  * Fall through to normal (VT_AUTO) handling of the switch...
1387                  */
1388         }
1389
1390         /*
1391          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1392          */
1393         if (vc->vc_mode == KD_GRAPHICS)
1394                 return;
1395
1396         complete_change_console(new_vc);
1397 }
1398
1399 /* Perform a kernel triggered VT switch for suspend/resume */
1400
1401 static int disable_vt_switch;
1402
1403 int vt_move_to_console(unsigned int vt, int alloc)
1404 {
1405         int prev;
1406
1407         console_lock();
1408         /* Graphics mode - up to X */
1409         if (disable_vt_switch) {
1410                 console_unlock();
1411                 return 0;
1412         }
1413         prev = fg_console;
1414
1415         if (alloc && vc_allocate(vt)) {
1416                 /* we can't have a free VC for now. Too bad,
1417                  * we don't want to mess the screen for now. */
1418                 console_unlock();
1419                 return -ENOSPC;
1420         }
1421
1422         if (set_console(vt)) {
1423                 /*
1424                  * We're unable to switch to the SUSPEND_CONSOLE.
1425                  * Let the calling function know so it can decide
1426                  * what to do.
1427                  */
1428                 console_unlock();
1429                 return -EIO;
1430         }
1431         console_unlock();
1432         if (vt_waitactive(vt + 1)) {
1433                 pr_debug("Suspend: Can't switch VCs.");
1434                 return -EINTR;
1435         }
1436         return prev;
1437 }
1438
1439 /*
1440  * Normally during a suspend, we allocate a new console and switch to it.
1441  * When we resume, we switch back to the original console.  This switch
1442  * can be slow, so on systems where the framebuffer can handle restoration
1443  * of video registers anyways, there's little point in doing the console
1444  * switch.  This function allows you to disable it by passing it '0'.
1445  */
1446 void pm_set_vt_switch(int do_switch)
1447 {
1448         console_lock();
1449         disable_vt_switch = !do_switch;
1450         console_unlock();
1451 }
1452 EXPORT_SYMBOL(pm_set_vt_switch);