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  * Called with the console lock held.
 251  */
 252 static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
 253 {
 254         switch (mode) {
 255         case KD_GRAPHICS:
 256                 break;
 257         case KD_TEXT0:
 258         case KD_TEXT1:
 259                 mode = KD_TEXT;
 260                 fallthrough;
 261         case KD_TEXT:
 262                 break;
 263         default:
 264                 return -EINVAL;
 265         }
 266
 267         if (vc->vc_mode == mode)
 268                 return 0;
 269
 270         vc->vc_mode = mode;
 271         if (vc->vc_num != fg_console)
 272                 return 0;
 273
 274         /* explicitly blank/unblank the screen if switching modes */
 275         if (mode == KD_TEXT)
 276                 do_unblank_screen(1);
 277         else
 278                 do_blank_screen(1);
 279
 280         return 0;
 281 }
 282
 283 static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
 284                 unsigned long arg, bool perm)
 285 {
 286         struct vc_data *vc = tty->driver_data;
 287         void __user *up = (void __user *)arg;
 288         unsigned int console = vc->vc_num;
 289         int ret;
 290
 291         switch (cmd) {
 292         case KIOCSOUND:
 293                 if (!perm)
 294                         return -EPERM;
 295                 /*
 296                  * The use of PIT_TICK_RATE is historic, it used to be
 297                  * the platform-dependent CLOCK_TICK_RATE between 2.6.12
 298                  * and 2.6.36, which was a minor but unfortunate ABI
 299                  * change. kd_mksound is locked by the input layer.
 300                  */
 301                 if (arg)
 302                         arg = PIT_TICK_RATE / arg;
 303                 kd_mksound(arg, 0);
 304                 break;
 305
 306         case KDMKTONE:
 307                 if (!perm)
 308                         return -EPERM;
 309         {
 310                 unsigned int ticks, count;
 311
 312                 /*
 313                  * Generate the tone for the appropriate number of ticks.
 314                  * If the time is zero, turn off sound ourselves.
 315                  */
 316                 ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
 317                 count = ticks ? (arg & 0xffff) : 0;
 318                 if (count)
 319                         count = PIT_TICK_RATE / count;
 320                 kd_mksound(count, ticks);
 321                 break;
 322         }
 323
 324         case KDGKBTYPE:
 325                 /*
 326                  * this is naïve.
 327                  */
 328                 return put_user(KB_101, (char __user *)arg);
 329
 330                 /*
 331                  * These cannot be implemented on any machine that implements
 332                  * ioperm() in user level (such as Alpha PCs) or not at all.
 333                  *
 334                  * XXX: you should never use these, just call ioperm directly..
 335                  */
 336 #ifdef CONFIG_X86
 337         case KDADDIO:
 338         case KDDELIO:
 339                 /*
 340                  * KDADDIO and KDDELIO may be able to add ports beyond what
 341                  * we reject here, but to be safe...
 342                  *
 343                  * These are locked internally via sys_ioperm
 344                  */
 345                 if (arg < GPFIRST || arg > GPLAST)
 346                         return -EINVAL;
 347
 348                 return ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 349
 350         case KDENABIO:
 351         case KDDISABIO:
 352                 return ksys_ioperm(GPFIRST, GPNUM,
 353                                   (cmd == KDENABIO)) ? -ENXIO : 0;
 354 #endif
 355
 356         /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
 357
 358         case KDKBDREP:
 359         {
 360                 struct kbd_repeat kbrep;
 361
 362                 if (!capable(CAP_SYS_TTY_CONFIG))
 363                         return -EPERM;
 364
 365                 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
 366                         return -EFAULT;
 367
 368                 ret = kbd_rate(&kbrep);
 369                 if (ret)
 370                         return ret;
 371                 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
 372                         return -EFAULT;
 373                 break;
 374         }
 375
 376         case KDSETMODE:
 377                 if (!perm)
 378                         return -EPERM;
 379
 380                 console_lock();
 381                 ret = vt_kdsetmode(vc, arg);
 382                 console_unlock();
 383                 return ret;
 384
 385         case KDGETMODE:
 386                 return put_user(vc->vc_mode, (int __user *)arg);
 387
 388         case KDMAPDISP:
 389         case KDUNMAPDISP:
 390                 /*
 391                  * these work like a combination of mmap and KDENABIO.
 392                  * this could be easily finished.
 393                  */
 394                 return -EINVAL;
 395
 396         case KDSKBMODE:
 397                 if (!perm)
 398                         return -EPERM;
 399                 ret = vt_do_kdskbmode(console, arg);
 400                 if (ret)
 401                         return ret;
 402                 tty_ldisc_flush(tty);
 403                 break;
 404
 405         case KDGKBMODE:
 406                 return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
 407
 408         /* this could be folded into KDSKBMODE, but for compatibility
 409            reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 410         case KDSKBMETA:
 411                 return vt_do_kdskbmeta(console, arg);
 412
 413         case KDGKBMETA:
 414                 /* FIXME: should review whether this is worth locking */
 415                 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
 416
 417         case KDGETKEYCODE:
 418         case KDSETKEYCODE:
 419                 if(!capable(CAP_SYS_TTY_CONFIG))
 420                         perm = 0;
 421                 return vt_do_kbkeycode_ioctl(cmd, up, perm);
 422
 423         case KDGKBENT:
 424         case KDSKBENT:
 425                 return vt_do_kdsk_ioctl(cmd, up, perm, console);
 426
 427         case KDGKBSENT:
 428         case KDSKBSENT:
 429                 return vt_do_kdgkb_ioctl(cmd, up, perm);
 430
 431         /* Diacritical processing. Handled in keyboard.c as it has
 432            to operate on the keyboard locks and structures */
 433         case KDGKBDIACR:
 434         case KDGKBDIACRUC:
 435         case KDSKBDIACR:
 436         case KDSKBDIACRUC:
 437                 return vt_do_diacrit(cmd, up, perm);
 438
 439         /* the ioctls below read/set the flags usually shown in the leds */
 440         /* don't use them - they will go away without warning */
 441         case KDGKBLED:
 442         case KDSKBLED:
 443         case KDGETLED:
 444         case KDSETLED:
 445                 return vt_do_kdskled(console, cmd, arg, perm);
 446
 447         /*
 448          * A process can indicate its willingness to accept signals
 449          * generated by pressing an appropriate key combination.
 450          * Thus, one can have a daemon that e.g. spawns a new console
 451          * upon a keypress and then changes to it.
 452          * See also the kbrequest field of inittab(5).
 453          */
 454         case KDSIGACCEPT:
 455                 if (!perm || !capable(CAP_KILL))
 456                         return -EPERM;
 457                 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
 458                         return -EINVAL;
 459
 460                 spin_lock_irq(&vt_spawn_con.lock);
 461                 put_pid(vt_spawn_con.pid);
 462                 vt_spawn_con.pid = get_pid(task_pid(current));
 463                 vt_spawn_con.sig = arg;
 464                 spin_unlock_irq(&vt_spawn_con.lock);
 465                 break;
 466
 467         case KDFONTOP: {
 468                 struct console_font_op op;
 469
 470                 if (copy_from_user(&op, up, sizeof(op)))
 471                         return -EFAULT;
 472                 if (!perm && op.op != KD_FONT_OP_GET)
 473                         return -EPERM;
 474                 ret = con_font_op(vc, &op);
 475                 if (ret)
 476                         return ret;
 477                 if (copy_to_user(up, &op, sizeof(op)))
 478                         return -EFAULT;
 479                 break;
 480         }
 481
 482         default:
 483                 return -ENOIOCTLCMD;
 484         }
 485
 486         return 0;
 487 }
 488
 489 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
 490                 bool perm, struct vc_data *vc)
 491 {
 492         struct unimapdesc tmp;
 493
 494         if (copy_from_user(&tmp, user_ud, sizeof tmp))
 495                 return -EFAULT;
 496         switch (cmd) {
 497         case PIO_UNIMAP:
 498                 if (!perm)
 499                         return -EPERM;
 500                 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
 501         case GIO_UNIMAP:
 502                 if (!perm && fg_console != vc->vc_num)
 503                         return -EPERM;
 504                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
 505                                 tmp.entries);
 506         }
 507         return 0;
 508 }
 509
 510 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
 511                 bool perm)
 512 {
 513         switch (cmd) {
 514         case PIO_CMAP:
 515                 if (!perm)
 516                         return -EPERM;
 517                 return con_set_cmap(up);
 518
 519         case GIO_CMAP:
 520                 return con_get_cmap(up);
 521
 522         case PIO_SCRNMAP:
 523                 if (!perm)
 524                         return -EPERM;
 525                 return con_set_trans_old(up);
 526
 527         case GIO_SCRNMAP:
 528                 return con_get_trans_old(up);
 529
 530         case PIO_UNISCRNMAP:
 531                 if (!perm)
 532                         return -EPERM;
 533                 return con_set_trans_new(up);
 534
 535         case GIO_UNISCRNMAP:
 536                 return con_get_trans_new(up);
 537
 538         case PIO_UNIMAPCLR:
 539                 if (!perm)
 540                         return -EPERM;
 541                 con_clear_unimap(vc);
 542                 break;
 543
 544         case PIO_UNIMAP:
 545         case GIO_UNIMAP:
 546                 return do_unimap_ioctl(cmd, up, perm, vc);
 547
 548         default:
 549                 return -ENOIOCTLCMD;
 550         }
 551
 552         return 0;
 553 }
 554
 555 static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
 556 {
 557         int newvt, ret;
 558
 559         if (vc->vt_mode.mode != VT_PROCESS)
 560                 return -EINVAL;
 561
 562         /* Switched-to response */
 563         if (vc->vt_newvt < 0) {
 564                  /* If it's just an ACK, ignore it */
 565                 return swtch == VT_ACKACQ ? 0 : -EINVAL;
 566         }
 567
 568         /* Switching-from response */
 569         if (swtch == 0) {
 570                 /* Switch disallowed, so forget we were trying to do it. */
 571                 vc->vt_newvt = -1;
 572                 return 0;
 573         }
 574
 575         /* The current vt has been released, so complete the switch. */
 576         newvt = vc->vt_newvt;
 577         vc->vt_newvt = -1;
 578         ret = vc_allocate(newvt);
 579         if (ret)
 580                 return ret;
 581
 582         /*
 583          * When we actually do the console switch, make sure we are atomic with
 584          * respect to other console switches..
 585          */
 586         complete_change_console(vc_cons[newvt].d);
 587
 588         return 0;
 589 }
 590
 591 static int vt_setactivate(struct vt_setactivate __user *sa)
 592 {
 593         struct vt_setactivate vsa;
 594         struct vc_data *nvc;
 595         int ret;
 596
 597         if (copy_from_user(&vsa, sa, sizeof(vsa)))
 598                 return -EFAULT;
 599         if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
 600                 return -ENXIO;
 601
 602         vsa.console--;
 603         vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES);
 604         console_lock();
 605         ret = vc_allocate(vsa.console);
 606         if (ret) {
 607                 console_unlock();
 608                 return ret;
 609         }
 610
 611         /*
 612          * This is safe providing we don't drop the console sem between
 613          * vc_allocate and finishing referencing nvc.
 614          */
 615         nvc = vc_cons[vsa.console].d;
 616         nvc->vt_mode = vsa.mode;
 617         nvc->vt_mode.frsig = 0;
 618         put_pid(nvc->vt_pid);
 619         nvc->vt_pid = get_pid(task_pid(current));
 620         console_unlock();
 621
 622         /* Commence switch and lock */
 623         /* Review set_console locks */
 624         set_console(vsa.console);
 625
 626         return 0;
 627 }
 628
 629 /* deallocate a single console, if possible (leave 0) */
 630 static int vt_disallocate(unsigned int vc_num)
 631 {
 632         struct vc_data *vc = NULL;
 633         int ret = 0;
 634
 635         console_lock();
 636         if (vt_busy(vc_num))
 637                 ret = -EBUSY;
 638         else if (vc_num)
 639                 vc = vc_deallocate(vc_num);
 640         console_unlock();
 641
 642         if (vc && vc_num >= MIN_NR_CONSOLES)
 643                 tty_port_put(&vc->port);
 644
 645         return ret;
 646 }
 647
 648 /* deallocate all unused consoles, but leave 0 */
 649 static void vt_disallocate_all(void)
 650 {
 651         struct vc_data *vc[MAX_NR_CONSOLES];
 652         int i;
 653
 654         console_lock();
 655         for (i = 1; i < MAX_NR_CONSOLES; i++)
 656                 if (!vt_busy(i))
 657                         vc[i] = vc_deallocate(i);
 658                 else
 659                         vc[i] = NULL;
 660         console_unlock();
 661
 662         for (i = 1; i < MAX_NR_CONSOLES; i++) {
 663                 if (vc[i] && i >= MIN_NR_CONSOLES)
 664                         tty_port_put(&vc[i]->port);
 665         }
 666 }
 667
 668 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
 669 {
 670         struct vt_consize v;
 671         int i;
 672
 673         if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
 674                 return -EFAULT;
 675
 676         /* FIXME: Should check the copies properly */
 677         if (!v.v_vlin)
 678                 v.v_vlin = vc->vc_scan_lines;
 679
 680         if (v.v_clin) {
 681                 int rows = v.v_vlin / v.v_clin;
 682                 if (v.v_rows != rows) {
 683                         if (v.v_rows) /* Parameters don't add up */
 684                                 return -EINVAL;
 685                         v.v_rows = rows;
 686                 }
 687         }
 688
 689         if (v.v_vcol && v.v_ccol) {
 690                 int cols = v.v_vcol / v.v_ccol;
 691                 if (v.v_cols != cols) {
 692                         if (v.v_cols)
 693                                 return -EINVAL;
 694                         v.v_cols = cols;
 695                 }
 696         }
 697
 698         if (v.v_clin > 32)
 699                 return -EINVAL;
 700
 701         for (i = 0; i < MAX_NR_CONSOLES; i++) {
 702                 struct vc_data *vcp;
 703
 704                 if (!vc_cons[i].d)
 705                         continue;
 706                 console_lock();
 707                 vcp = vc_cons[i].d;
 708                 if (vcp) {
 709                         int ret;
 710                         int save_scan_lines = vcp->vc_scan_lines;
 711                         int save_cell_height = vcp->vc_cell_height;
 712
 713                         if (v.v_vlin)
 714                                 vcp->vc_scan_lines = v.v_vlin;
 715                         if (v.v_clin)
 716                                 vcp->vc_cell_height = v.v_clin;
 717                         ret = __vc_resize(vcp, v.v_cols, v.v_rows, true);
 718                         if (ret) {
 719                                 vcp->vc_scan_lines = save_scan_lines;
 720                                 vcp->vc_cell_height = save_cell_height;
 721                                 console_unlock();
 722                                 return ret;
 723                         }
 724                 }
 725                 console_unlock();
 726         }
 727
 728         return 0;
 729 }
 730
 731 /*
 732  * We handle the console-specific ioctl's here.  We allow the
 733  * capability to modify any console, not just the fg_console.
 734  */
 735 int vt_ioctl(struct tty_struct *tty,
 736              unsigned int cmd, unsigned long arg)
 737 {
 738         struct vc_data *vc = tty->driver_data;
 739         void __user *up = (void __user *)arg;
 740         int i, perm;
 741         int ret;
 742
 743         /*
 744          * To have permissions to do most of the vt ioctls, we either have
 745          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
 746          */
 747         perm = 0;
 748         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
 749                 perm = 1;
 750
 751         ret = vt_k_ioctl(tty, cmd, arg, perm);
 752         if (ret != -ENOIOCTLCMD)
 753                 return ret;
 754
 755         ret = vt_io_ioctl(vc, cmd, up, perm);
 756         if (ret != -ENOIOCTLCMD)
 757                 return ret;
 758
 759         switch (cmd) {
 760         case TIOCLINUX:
 761                 return tioclinux(tty, arg);
 762         case VT_SETMODE:
 763         {
 764                 struct vt_mode tmp;
 765
 766                 if (!perm)
 767                         return -EPERM;
 768                 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
 769                         return -EFAULT;
 770                 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
 771                         return -EINVAL;
 772
 773                 console_lock();
 774                 vc->vt_mode = tmp;
 775                 /* the frsig is ignored, so we set it to 0 */
 776                 vc->vt_mode.frsig = 0;
 777                 put_pid(vc->vt_pid);
 778                 vc->vt_pid = get_pid(task_pid(current));
 779                 /* no switch is required -- saw@shade.msu.ru */
 780                 vc->vt_newvt = -1;
 781                 console_unlock();
 782                 break;
 783         }
 784
 785         case VT_GETMODE:
 786         {
 787                 struct vt_mode tmp;
 788                 int rc;
 789
 790                 console_lock();
 791                 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
 792                 console_unlock();
 793
 794                 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
 795                 if (rc)
 796                         return -EFAULT;
 797                 break;
 798         }
 799
 800         /*
 801          * Returns global vt state. Note that VT 0 is always open, since
 802          * it's an alias for the current VT, and people can't use it here.
 803          * We cannot return state for more than 16 VTs, since v_state is short.
 804          */
 805         case VT_GETSTATE:
 806         {
 807                 struct vt_stat __user *vtstat = up;
 808                 unsigned short state, mask;
 809
 810                 if (put_user(fg_console + 1, &vtstat->v_active))
 811                         return -EFAULT;
 812
 813                 state = 1;      /* /dev/tty0 is always open */
 814                 console_lock(); /* required by vt_in_use() */
 815                 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
 816                                 ++i, mask <<= 1)
 817                         if (vt_in_use(i))
 818                                 state |= mask;
 819                 console_unlock();
 820                 return put_user(state, &vtstat->v_state);
 821         }
 822
 823         /*
 824          * Returns the first available (non-opened) console.
 825          */
 826         case VT_OPENQRY:
 827                 console_lock(); /* required by vt_in_use() */
 828                 for (i = 0; i < MAX_NR_CONSOLES; ++i)
 829                         if (!vt_in_use(i))
 830                                 break;
 831                 console_unlock();
 832                 i = i < MAX_NR_CONSOLES ? (i+1) : -1;
 833                 return put_user(i, (int __user *)arg);
 834
 835         /*
 836          * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
 837          * with num >= 1 (switches to vt 0, our console, are not allowed, just
 838          * to preserve sanity).
 839          */
 840         case VT_ACTIVATE:
 841                 if (!perm)
 842                         return -EPERM;
 843                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 844                         return -ENXIO;
 845
 846                 arg--;
 847                 arg = array_index_nospec(arg, MAX_NR_CONSOLES);
 848                 console_lock();
 849                 ret = vc_allocate(arg);
 850                 console_unlock();
 851                 if (ret)
 852                         return ret;
 853                 set_console(arg);
 854                 break;
 855
 856         case VT_SETACTIVATE:
 857                 if (!perm)
 858                         return -EPERM;
 859
 860                 return vt_setactivate(up);
 861
 862         /*
 863          * wait until the specified VT has been activated
 864          */
 865         case VT_WAITACTIVE:
 866                 if (!perm)
 867                         return -EPERM;
 868                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 869                         return -ENXIO;
 870                 return vt_waitactive(arg);
 871
 872         /*
 873          * If a vt is under process control, the kernel will not switch to it
 874          * immediately, but postpone the operation until the process calls this
 875          * ioctl, allowing the switch to complete.
 876          *
 877          * According to the X sources this is the behavior:
 878          *      0:      pending switch-from not OK
 879          *      1:      pending switch-from OK
 880          *      2:      completed switch-to OK
 881          */
 882         case VT_RELDISP:
 883                 if (!perm)
 884                         return -EPERM;
 885
 886                 console_lock();
 887                 ret = vt_reldisp(vc, arg);
 888                 console_unlock();
 889
 890                 return ret;
 891
 892
 893          /*
 894           * Disallocate memory associated to VT (but leave VT1)
 895           */
 896          case VT_DISALLOCATE:
 897                 if (arg > MAX_NR_CONSOLES)
 898                         return -ENXIO;
 899
 900                 if (arg == 0) {
 901                         vt_disallocate_all();
 902                         break;
 903                 }
 904
 905                 arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES);
 906                 return vt_disallocate(arg);
 907
 908         case VT_RESIZE:
 909         {
 910                 struct vt_sizes __user *vtsizes = up;
 911                 struct vc_data *vc;
 912                 ushort ll,cc;
 913
 914                 if (!perm)
 915                         return -EPERM;
 916                 if (get_user(ll, &vtsizes->v_rows) ||
 917                     get_user(cc, &vtsizes->v_cols))
 918                         return -EFAULT;
 919
 920                 console_lock();
 921                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 922                         vc = vc_cons[i].d;
 923
 924                         if (vc) {
 925                                 /* FIXME: review v tty lock */
 926                                 __vc_resize(vc_cons[i].d, cc, ll, true);
 927                         }
 928                 }
 929                 console_unlock();
 930                 break;
 931         }
 932
 933         case VT_RESIZEX:
 934                 if (!perm)
 935                         return -EPERM;
 936
 937                 return vt_resizex(vc, up);
 938
 939         case VT_LOCKSWITCH:
 940                 if (!capable(CAP_SYS_TTY_CONFIG))
 941                         return -EPERM;
 942                 vt_dont_switch = true;
 943                 break;
 944         case VT_UNLOCKSWITCH:
 945                 if (!capable(CAP_SYS_TTY_CONFIG))
 946                         return -EPERM;
 947                 vt_dont_switch = false;
 948                 break;
 949         case VT_GETHIFONTMASK:
 950                 return put_user(vc->vc_hi_font_mask,
 951                                         (unsigned short __user *)arg);
 952         case VT_WAITEVENT:
 953                 return vt_event_wait_ioctl((struct vt_event __user *)arg);
 954         default:
 955                 return -ENOIOCTLCMD;
 956         }
 957
 958         return 0;
 959 }
 960
 961 void reset_vc(struct vc_data *vc)
 962 {
 963         vc->vc_mode = KD_TEXT;
 964         vt_reset_unicode(vc->vc_num);
 965         vc->vt_mode.mode = VT_AUTO;
 966         vc->vt_mode.waitv = 0;
 967         vc->vt_mode.relsig = 0;
 968         vc->vt_mode.acqsig = 0;
 969         vc->vt_mode.frsig = 0;
 970         put_pid(vc->vt_pid);
 971         vc->vt_pid = NULL;
 972         vc->vt_newvt = -1;
 973         reset_palette(vc);
 974 }
 975
 976 void vc_SAK(struct work_struct *work)
 977 {
 978         struct vc *vc_con =
 979                 container_of(work, struct vc, SAK_work);
 980         struct vc_data *vc;
 981         struct tty_struct *tty;
 982
 983         console_lock();
 984         vc = vc_con->d;
 985         if (vc) {
 986                 /* FIXME: review tty ref counting */
 987                 tty = vc->port.tty;
 988                 /*
 989                  * SAK should also work in all raw modes and reset
 990                  * them properly.
 991                  */
 992                 if (tty)
 993                         __do_SAK(tty);
 994                 reset_vc(vc);
 995         }
 996         console_unlock();
 997 }
 998
 999 #ifdef CONFIG_COMPAT
1000
1001 struct compat_console_font_op {
1002         compat_uint_t op;        /* operation code KD_FONT_OP_* */
1003         compat_uint_t flags;     /* KD_FONT_FLAG_* */
1004         compat_uint_t width, height;     /* font size */
1005         compat_uint_t charcount;
1006         compat_caddr_t data;    /* font data with height fixed to 32 */
1007 };
1008
1009 static inline int
1010 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1011                          int perm, struct console_font_op *op, struct vc_data *vc)
1012 {
1013         int i;
1014
1015         if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1016                 return -EFAULT;
1017         if (!perm && op->op != KD_FONT_OP_GET)
1018                 return -EPERM;
1019         op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1020         i = con_font_op(vc, op);
1021         if (i)
1022                 return i;
1023         ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1024         if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1025                 return -EFAULT;
1026         return 0;
1027 }
1028
1029 struct compat_unimapdesc {
1030         unsigned short entry_ct;
1031         compat_caddr_t entries;
1032 };
1033
1034 static inline int
1035 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1036                          int perm, struct vc_data *vc)
1037 {
1038         struct compat_unimapdesc tmp;
1039         struct unipair __user *tmp_entries;
1040
1041         if (copy_from_user(&tmp, user_ud, sizeof tmp))
1042                 return -EFAULT;
1043         tmp_entries = compat_ptr(tmp.entries);
1044         switch (cmd) {
1045         case PIO_UNIMAP:
1046                 if (!perm)
1047                         return -EPERM;
1048                 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1049         case GIO_UNIMAP:
1050                 if (!perm && fg_console != vc->vc_num)
1051                         return -EPERM;
1052                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1053         }
1054         return 0;
1055 }
1056
1057 long vt_compat_ioctl(struct tty_struct *tty,
1058              unsigned int cmd, unsigned long arg)
1059 {
1060         struct vc_data *vc = tty->driver_data;
1061         struct console_font_op op;      /* used in multiple places here */
1062         void __user *up = compat_ptr(arg);
1063         int perm;
1064
1065         /*
1066          * To have permissions to do most of the vt ioctls, we either have
1067          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1068          */
1069         perm = 0;
1070         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1071                 perm = 1;
1072
1073         switch (cmd) {
1074         /*
1075          * these need special handlers for incompatible data structures
1076          */
1077
1078         case KDFONTOP:
1079                 return compat_kdfontop_ioctl(up, perm, &op, vc);
1080
1081         case PIO_UNIMAP:
1082         case GIO_UNIMAP:
1083                 return compat_unimap_ioctl(cmd, up, perm, vc);
1084
1085         /*
1086          * all these treat 'arg' as an integer
1087          */
1088         case KIOCSOUND:
1089         case KDMKTONE:
1090 #ifdef CONFIG_X86
1091         case KDADDIO:
1092         case KDDELIO:
1093 #endif
1094         case KDSETMODE:
1095         case KDMAPDISP:
1096         case KDUNMAPDISP:
1097         case KDSKBMODE:
1098         case KDSKBMETA:
1099         case KDSKBLED:
1100         case KDSETLED:
1101         case KDSIGACCEPT:
1102         case VT_ACTIVATE:
1103         case VT_WAITACTIVE:
1104         case VT_RELDISP:
1105         case VT_DISALLOCATE:
1106         case VT_RESIZE:
1107         case VT_RESIZEX:
1108                 return vt_ioctl(tty, cmd, arg);
1109
1110         /*
1111          * the rest has a compatible data structure behind arg,
1112          * but we have to convert it to a proper 64 bit pointer.
1113          */
1114         default:
1115                 return vt_ioctl(tty, cmd, (unsigned long)up);
1116         }
1117 }
1118
1119
1120 #endif /* CONFIG_COMPAT */
1121
1122
1123 /*
1124  * Performs the back end of a vt switch. Called under the console
1125  * semaphore.
1126  */
1127 static void complete_change_console(struct vc_data *vc)
1128 {
1129         unsigned char old_vc_mode;
1130         int old = fg_console;
1131
1132         last_console = fg_console;
1133
1134         /*
1135          * If we're switching, we could be going from KD_GRAPHICS to
1136          * KD_TEXT mode or vice versa, which means we need to blank or
1137          * unblank the screen later.
1138          */
1139         old_vc_mode = vc_cons[fg_console].d->vc_mode;
1140         switch_screen(vc);
1141
1142         /*
1143          * This can't appear below a successful kill_pid().  If it did,
1144          * then the *blank_screen operation could occur while X, having
1145          * received acqsig, is waking up on another processor.  This
1146          * condition can lead to overlapping accesses to the VGA range
1147          * and the framebuffer (causing system lockups).
1148          *
1149          * To account for this we duplicate this code below only if the
1150          * controlling process is gone and we've called reset_vc.
1151          */
1152         if (old_vc_mode != vc->vc_mode) {
1153                 if (vc->vc_mode == KD_TEXT)
1154                         do_unblank_screen(1);
1155                 else
1156                         do_blank_screen(1);
1157         }
1158
1159         /*
1160          * If this new console is under process control, send it a signal
1161          * telling it that it has acquired. Also check if it has died and
1162          * clean up (similar to logic employed in change_console())
1163          */
1164         if (vc->vt_mode.mode == VT_PROCESS) {
1165                 /*
1166                  * Send the signal as privileged - kill_pid() will
1167                  * tell us if the process has gone or something else
1168                  * is awry
1169                  */
1170                 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1171                 /*
1172                  * The controlling process has died, so we revert back to
1173                  * normal operation. In this case, we'll also change back
1174                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1175                  * but it saves the agony when the X server dies and the screen
1176                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1177                  * this outside of VT_PROCESS but there is no single process
1178                  * to account for and tracking tty count may be undesirable.
1179                  */
1180                         reset_vc(vc);
1181
1182                         if (old_vc_mode != vc->vc_mode) {
1183                                 if (vc->vc_mode == KD_TEXT)
1184                                         do_unblank_screen(1);
1185                                 else
1186                                         do_blank_screen(1);
1187                         }
1188                 }
1189         }
1190
1191         /*
1192          * Wake anyone waiting for their VT to activate
1193          */
1194         vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1195         return;
1196 }
1197
1198 /*
1199  * Performs the front-end of a vt switch
1200  */
1201 void change_console(struct vc_data *new_vc)
1202 {
1203         struct vc_data *vc;
1204
1205         if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1206                 return;
1207
1208         /*
1209          * If this vt is in process mode, then we need to handshake with
1210          * that process before switching. Essentially, we store where that
1211          * vt wants to switch to and wait for it to tell us when it's done
1212          * (via VT_RELDISP ioctl).
1213          *
1214          * We also check to see if the controlling process still exists.
1215          * If it doesn't, we reset this vt to auto mode and continue.
1216          * This is a cheap way to track process control. The worst thing
1217          * that can happen is: we send a signal to a process, it dies, and
1218          * the switch gets "lost" waiting for a response; hopefully, the
1219          * user will try again, we'll detect the process is gone (unless
1220          * the user waits just the right amount of time :-) and revert the
1221          * vt to auto control.
1222          */
1223         vc = vc_cons[fg_console].d;
1224         if (vc->vt_mode.mode == VT_PROCESS) {
1225                 /*
1226                  * Send the signal as privileged - kill_pid() will
1227                  * tell us if the process has gone or something else
1228                  * is awry.
1229                  *
1230                  * We need to set vt_newvt *before* sending the signal or we
1231                  * have a race.
1232                  */
1233                 vc->vt_newvt = new_vc->vc_num;
1234                 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1235                         /*
1236                          * It worked. Mark the vt to switch to and
1237                          * return. The process needs to send us a
1238                          * VT_RELDISP ioctl to complete the switch.
1239                          */
1240                         return;
1241                 }
1242
1243                 /*
1244                  * The controlling process has died, so we revert back to
1245                  * normal operation. In this case, we'll also change back
1246                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1247                  * but it saves the agony when the X server dies and the screen
1248                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1249                  * this outside of VT_PROCESS but there is no single process
1250                  * to account for and tracking tty count may be undesirable.
1251                  */
1252                 reset_vc(vc);
1253
1254                 /*
1255                  * Fall through to normal (VT_AUTO) handling of the switch...
1256                  */
1257         }
1258
1259         /*
1260          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1261          */
1262         if (vc->vc_mode == KD_GRAPHICS)
1263                 return;
1264
1265         complete_change_console(new_vc);
1266 }
1267
1268 /* Perform a kernel triggered VT switch for suspend/resume */
1269
1270 static int disable_vt_switch;
1271
1272 int vt_move_to_console(unsigned int vt, int alloc)
1273 {
1274         int prev;
1275
1276         console_lock();
1277         /* Graphics mode - up to X */
1278         if (disable_vt_switch) {
1279                 console_unlock();
1280                 return 0;
1281         }
1282         prev = fg_console;
1283
1284         if (alloc && vc_allocate(vt)) {
1285                 /* we can't have a free VC for now. Too bad,
1286                  * we don't want to mess the screen for now. */
1287                 console_unlock();
1288                 return -ENOSPC;
1289         }
1290
1291         if (set_console(vt)) {
1292                 /*
1293                  * We're unable to switch to the SUSPEND_CONSOLE.
1294                  * Let the calling function know so it can decide
1295                  * what to do.
1296                  */
1297                 console_unlock();
1298                 return -EIO;
1299         }
1300         console_unlock();
1301         if (vt_waitactive(vt + 1)) {
1302                 pr_debug("Suspend: Can't switch VCs.");
1303                 return -EINTR;
1304         }
1305         return prev;
1306 }
1307
1308 /*
1309  * Normally during a suspend, we allocate a new console and switch to it.
1310  * When we resume, we switch back to the original console.  This switch
1311  * can be slow, so on systems where the framebuffer can handle restoration
1312  * of video registers anyways, there's little point in doing the console
1313  * switch.  This function allows you to disable it by passing it '0'.
1314  */
1315 void pm_set_vt_switch(int do_switch)
1316 {
1317         console_lock();
1318         disable_vt_switch = !do_switch;
1319         console_unlock();
1320 }
1321 EXPORT_SYMBOL(pm_set_vt_switch);