drivers/char/vt_ioctl.c

   1 /*
   2  *  linux/drivers/char/vt_ioctl.c
   3  *
   4  *  Copyright (C) 1992 obz under the linux copyright
   5  *
   6  *  Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
   7  *  Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
   8  *  Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
   9  *  Some code moved for less code duplication - Andi Kleen - Mar 1997
  10  *  Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/sched.h>
  17 #include <linux/tty.h>
  18 #include <linux/timer.h>
  19 #include <linux/kernel.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/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 static 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  * these are the valid i/o ports we're allowed to change. they map all the
  65  * video ports
  66  */
  67 #define GPFIRST 0x3b4
  68 #define GPLAST 0x3df
  69 #define GPNUM (GPLAST - GPFIRST + 1)
  70
  71 #define i (tmp.kb_index)
  72 #define s (tmp.kb_table)
  73 #define v (tmp.kb_value)
  74 static inline int
  75 do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe, int perm, struct kbd_struct *kbd)
  76 {
  77         struct kbentry tmp;
  78         ushort *key_map, val, ov;
  79
  80         if (copy_from_user(&tmp, user_kbe, sizeof(struct kbentry)))
  81                 return -EFAULT;
  82
  83         switch (cmd) {
  84         case KDGKBENT:
  85                 key_map = key_maps[s];
  86                 if (key_map) {
  87                     val = U(key_map[i]);
  88                     if (kbd->kbdmode != VC_UNICODE && KTYP(val) >= NR_TYPES)
  89                         val = K_HOLE;
  90                 } else
  91                     val = (i ? K_HOLE : K_NOSUCHMAP);
  92                 return put_user(val, &user_kbe->kb_value);
  93         case KDSKBENT:
  94                 if (!perm)
  95                         return -EPERM;
  96                 if (!i && v == K_NOSUCHMAP) {
  97                         /* disallocate map */
  98                         key_map = key_maps[s];
  99                         if (s && key_map) {
 100                             key_maps[s] = NULL;
 101                             if (key_map[0] == U(K_ALLOCATED)) {
 102                                         kfree(key_map);
 103                                         keymap_count--;
 104                             }
 105                         }
 106                         break;
 107                 }
 108
 109                 if (KTYP(v) < NR_TYPES) {
 110                     if (KVAL(v) > max_vals[KTYP(v)])
 111                                 return -EINVAL;
 112                 } else
 113                     if (kbd->kbdmode != VC_UNICODE)
 114                                 return -EINVAL;
 115
 116                 /* ++Geert: non-PC keyboards may generate keycode zero */
 117 #if !defined(__mc68000__) && !defined(__powerpc__)
 118                 /* assignment to entry 0 only tests validity of args */
 119                 if (!i)
 120                         break;
 121 #endif
 122
 123                 if (!(key_map = key_maps[s])) {
 124                         int j;
 125
 126                         if (keymap_count >= MAX_NR_OF_USER_KEYMAPS &&
 127                             !capable(CAP_SYS_RESOURCE))
 128                                 return -EPERM;
 129
 130                         key_map = (ushort *) kmalloc(sizeof(plain_map),
 131                                                      GFP_KERNEL);
 132                         if (!key_map)
 133                                 return -ENOMEM;
 134                         key_maps[s] = key_map;
 135                         key_map[0] = U(K_ALLOCATED);
 136                         for (j = 1; j < NR_KEYS; j++)
 137                                 key_map[j] = U(K_HOLE);
 138                         keymap_count++;
 139                 }
 140                 ov = U(key_map[i]);
 141                 if (v == ov)
 142                         break;  /* nothing to do */
 143                 /*
 144                  * Attention Key.
 145                  */
 146                 if (((ov == K_SAK) || (v == K_SAK)) && !capable(CAP_SYS_ADMIN))
 147                         return -EPERM;
 148                 key_map[i] = U(v);
 149                 if (!s && (KTYP(ov) == KT_SHIFT || KTYP(v) == KT_SHIFT))
 150                         compute_shiftstate();
 151                 break;
 152         }
 153         return 0;
 154 }
 155 #undef i
 156 #undef s
 157 #undef v
 158
 159 static inline int
 160 do_kbkeycode_ioctl(int cmd, struct kbkeycode __user *user_kbkc, int perm)
 161 {
 162         struct kbkeycode tmp;
 163         int kc = 0;
 164
 165         if (copy_from_user(&tmp, user_kbkc, sizeof(struct kbkeycode)))
 166                 return -EFAULT;
 167         switch (cmd) {
 168         case KDGETKEYCODE:
 169                 kc = getkeycode(tmp.scancode);
 170                 if (kc >= 0)
 171                         kc = put_user(kc, &user_kbkc->keycode);
 172                 break;
 173         case KDSETKEYCODE:
 174                 if (!perm)
 175                         return -EPERM;
 176                 kc = setkeycode(tmp.scancode, tmp.keycode);
 177                 break;
 178         }
 179         return kc;
 180 }
 181
 182 static inline int
 183 do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
 184 {
 185         struct kbsentry *kbs;
 186         char *p;
 187         u_char *q;
 188         u_char __user *up;
 189         int sz;
 190         int delta;
 191         char *first_free, *fj, *fnw;
 192         int i, j, k;
 193         int ret;
 194
 195         if (!capable(CAP_SYS_TTY_CONFIG))
 196                 return -EPERM;
 197
 198         kbs = kmalloc(sizeof(*kbs), GFP_KERNEL);
 199         if (!kbs) {
 200                 ret = -ENOMEM;
 201                 goto reterr;
 202         }
 203
 204         /* we mostly copy too much here (512bytes), but who cares ;) */
 205         if (copy_from_user(kbs, user_kdgkb, sizeof(struct kbsentry))) {
 206                 ret = -EFAULT;
 207                 goto reterr;
 208         }
 209         kbs->kb_string[sizeof(kbs->kb_string)-1] = '\0';
 210         i = kbs->kb_func;
 211
 212         switch (cmd) {
 213         case KDGKBSENT:
 214                 sz = sizeof(kbs->kb_string) - 1; /* sz should have been
 215                                                   a struct member */
 216                 up = user_kdgkb->kb_string;
 217                 p = func_table[i];
 218                 if(p)
 219                         for ( ; *p && sz; p++, sz--)
 220                                 if (put_user(*p, up++)) {
 221                                         ret = -EFAULT;
 222                                         goto reterr;
 223                                 }
 224                 if (put_user('\0', up)) {
 225                         ret = -EFAULT;
 226                         goto reterr;
 227                 }
 228                 kfree(kbs);
 229                 return ((p && *p) ? -EOVERFLOW : 0);
 230         case KDSKBSENT:
 231                 if (!perm) {
 232                         ret = -EPERM;
 233                         goto reterr;
 234                 }
 235
 236                 q = func_table[i];
 237                 first_free = funcbufptr + (funcbufsize - funcbufleft);
 238                 for (j = i+1; j < MAX_NR_FUNC && !func_table[j]; j++)
 239                         ;
 240                 if (j < MAX_NR_FUNC)
 241                         fj = func_table[j];
 242                 else
 243                         fj = first_free;
 244
 245                 delta = (q ? -strlen(q) : 1) + strlen(kbs->kb_string);
 246                 if (delta <= funcbufleft) {     /* it fits in current buf */
 247                     if (j < MAX_NR_FUNC) {
 248                         memmove(fj + delta, fj, first_free - fj);
 249                         for (k = j; k < MAX_NR_FUNC; k++)
 250                             if (func_table[k])
 251                                 func_table[k] += delta;
 252                     }
 253                     if (!q)
 254                       func_table[i] = fj;
 255                     funcbufleft -= delta;
 256                 } else {                        /* allocate a larger buffer */
 257                     sz = 256;
 258                     while (sz < funcbufsize - funcbufleft + delta)
 259                       sz <<= 1;
 260                     fnw = (char *) kmalloc(sz, GFP_KERNEL);
 261                     if(!fnw) {
 262                       ret = -ENOMEM;
 263                       goto reterr;
 264                     }
 265
 266                     if (!q)
 267                       func_table[i] = fj;
 268                     if (fj > funcbufptr)
 269                         memmove(fnw, funcbufptr, fj - funcbufptr);
 270                     for (k = 0; k < j; k++)
 271                       if (func_table[k])
 272                         func_table[k] = fnw + (func_table[k] - funcbufptr);
 273
 274                     if (first_free > fj) {
 275                         memmove(fnw + (fj - funcbufptr) + delta, fj, first_free - fj);
 276                         for (k = j; k < MAX_NR_FUNC; k++)
 277                           if (func_table[k])
 278                             func_table[k] = fnw + (func_table[k] - funcbufptr) + delta;
 279                     }
 280                     if (funcbufptr != func_buf)
 281                       kfree(funcbufptr);
 282                     funcbufptr = fnw;
 283                     funcbufleft = funcbufleft - delta + sz - funcbufsize;
 284                     funcbufsize = sz;
 285                 }
 286                 strcpy(func_table[i], kbs->kb_string);
 287                 break;
 288         }
 289         ret = 0;
 290 reterr:
 291         kfree(kbs);
 292         return ret;
 293 }
 294
 295 static inline int
 296 do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
 297 {
 298         struct consolefontdesc cfdarg;
 299         int i;
 300
 301         if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
 302                 return -EFAULT;
 303
 304         switch (cmd) {
 305         case PIO_FONTX:
 306                 if (!perm)
 307                         return -EPERM;
 308                 op->op = KD_FONT_OP_SET;
 309                 op->flags = KD_FONT_FLAG_OLD;
 310                 op->width = 8;
 311                 op->height = cfdarg.charheight;
 312                 op->charcount = cfdarg.charcount;
 313                 op->data = cfdarg.chardata;
 314                 return con_font_op(vc_cons[fg_console].d, op);
 315         case GIO_FONTX: {
 316                 op->op = KD_FONT_OP_GET;
 317                 op->flags = KD_FONT_FLAG_OLD;
 318                 op->width = 8;
 319                 op->height = cfdarg.charheight;
 320                 op->charcount = cfdarg.charcount;
 321                 op->data = cfdarg.chardata;
 322                 i = con_font_op(vc_cons[fg_console].d, op);
 323                 if (i)
 324                         return i;
 325                 cfdarg.charheight = op->height;
 326                 cfdarg.charcount = op->charcount;
 327                 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
 328                         return -EFAULT;
 329                 return 0;
 330                 }
 331         }
 332         return -EINVAL;
 333 }
 334
 335 static inline int
 336 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
 337 {
 338         struct unimapdesc tmp;
 339
 340         if (copy_from_user(&tmp, user_ud, sizeof tmp))
 341                 return -EFAULT;
 342         if (tmp.entries)
 343                 if (!access_ok(VERIFY_WRITE, tmp.entries,
 344                                 tmp.entry_ct*sizeof(struct unipair)))
 345                         return -EFAULT;
 346         switch (cmd) {
 347         case PIO_UNIMAP:
 348                 if (!perm)
 349                         return -EPERM;
 350                 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
 351         case GIO_UNIMAP:
 352                 if (!perm && fg_console != vc->vc_num)
 353                         return -EPERM;
 354                 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
 355         }
 356         return 0;
 357 }
 358
 359 /*
 360  * We handle the console-specific ioctl's here.  We allow the
 361  * capability to modify any console, not just the fg_console.
 362  */
 363 int vt_ioctl(struct tty_struct *tty, struct file * file,
 364              unsigned int cmd, unsigned long arg)
 365 {
 366         struct vc_data *vc = (struct vc_data *)tty->driver_data;
 367         struct console_font_op op;      /* used in multiple places here */
 368         struct kbd_struct * kbd;
 369         unsigned int console;
 370         unsigned char ucval;
 371         void __user *up = (void __user *)arg;
 372         int i, perm;
 373
 374         console = vc->vc_num;
 375
 376         if (!vc_cons_allocated(console))        /* impossible? */
 377                 return -ENOIOCTLCMD;
 378
 379         /*
 380          * To have permissions to do most of the vt ioctls, we either have
 381          * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
 382          */
 383         perm = 0;
 384         if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
 385                 perm = 1;
 386
 387         kbd = kbd_table + console;
 388         switch (cmd) {
 389         case KIOCSOUND:
 390                 if (!perm)
 391                         return -EPERM;
 392                 if (arg)
 393                         arg = CLOCK_TICK_RATE / arg;
 394                 kd_mksound(arg, 0);
 395                 return 0;
 396
 397         case KDMKTONE:
 398                 if (!perm)
 399                         return -EPERM;
 400         {
 401                 unsigned int ticks, count;
 402
 403                 /*
 404                  * Generate the tone for the appropriate number of ticks.
 405                  * If the time is zero, turn off sound ourselves.
 406                  */
 407                 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
 408                 count = ticks ? (arg & 0xffff) : 0;
 409                 if (count)
 410                         count = CLOCK_TICK_RATE / count;
 411                 kd_mksound(count, ticks);
 412                 return 0;
 413         }
 414
 415         case KDGKBTYPE:
 416                 /*
 417                  * this is naive.
 418                  */
 419                 ucval = KB_101;
 420                 goto setchar;
 421
 422                 /*
 423                  * These cannot be implemented on any machine that implements
 424                  * ioperm() in user level (such as Alpha PCs) or not at all.
 425                  *
 426                  * XXX: you should never use these, just call ioperm directly..
 427                  */
 428 #ifdef CONFIG_X86
 429         case KDADDIO:
 430         case KDDELIO:
 431                 /*
 432                  * KDADDIO and KDDELIO may be able to add ports beyond what
 433                  * we reject here, but to be safe...
 434                  */
 435                 if (arg < GPFIRST || arg > GPLAST)
 436                         return -EINVAL;
 437                 return sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 438
 439         case KDENABIO:
 440         case KDDISABIO:
 441                 return sys_ioperm(GPFIRST, GPNUM,
 442                                   (cmd == KDENABIO)) ? -ENXIO : 0;
 443 #endif
 444
 445         /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
 446
 447         case KDKBDREP:
 448         {
 449                 struct kbd_repeat kbrep;
 450                 int err;
 451
 452                 if (!capable(CAP_SYS_TTY_CONFIG))
 453                         return -EPERM;
 454
 455                 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
 456                         return -EFAULT;
 457                 err = kbd_rate(&kbrep);
 458                 if (err)
 459                         return err;
 460                 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
 461                         return -EFAULT;
 462                 return 0;
 463         }
 464
 465         case KDSETMODE:
 466                 /*
 467                  * currently, setting the mode from KD_TEXT to KD_GRAPHICS
 468                  * doesn't do a whole lot. i'm not sure if it should do any
 469                  * restoration of modes or what...
 470                  *
 471                  * XXX It should at least call into the driver, fbdev's definitely
 472                  * need to restore their engine state. --BenH
 473                  */
 474                 if (!perm)
 475                         return -EPERM;
 476                 switch (arg) {
 477                 case KD_GRAPHICS:
 478                         break;
 479                 case KD_TEXT0:
 480                 case KD_TEXT1:
 481                         arg = KD_TEXT;
 482                 case KD_TEXT:
 483                         break;
 484                 default:
 485                         return -EINVAL;
 486                 }
 487                 if (vc->vc_mode == (unsigned char) arg)
 488                         return 0;
 489                 vc->vc_mode = (unsigned char) arg;
 490                 if (console != fg_console)
 491                         return 0;
 492                 /*
 493                  * explicitly blank/unblank the screen if switching modes
 494                  */
 495                 acquire_console_sem();
 496                 if (arg == KD_TEXT)
 497                         do_unblank_screen(1);
 498                 else
 499                         do_blank_screen(1);
 500                 release_console_sem();
 501                 return 0;
 502
 503         case KDGETMODE:
 504                 ucval = vc->vc_mode;
 505                 goto setint;
 506
 507         case KDMAPDISP:
 508         case KDUNMAPDISP:
 509                 /*
 510                  * these work like a combination of mmap and KDENABIO.
 511                  * this could be easily finished.
 512                  */
 513                 return -EINVAL;
 514
 515         case KDSKBMODE:
 516                 if (!perm)
 517                         return -EPERM;
 518                 switch(arg) {
 519                   case K_RAW:
 520                         kbd->kbdmode = VC_RAW;
 521                         break;
 522                   case K_MEDIUMRAW:
 523                         kbd->kbdmode = VC_MEDIUMRAW;
 524                         break;
 525                   case K_XLATE:
 526                         kbd->kbdmode = VC_XLATE;
 527                         compute_shiftstate();
 528                         break;
 529                   case K_UNICODE:
 530                         kbd->kbdmode = VC_UNICODE;
 531                         compute_shiftstate();
 532                         break;
 533                   default:
 534                         return -EINVAL;
 535                 }
 536                 tty_ldisc_flush(tty);
 537                 return 0;
 538
 539         case KDGKBMODE:
 540                 ucval = ((kbd->kbdmode == VC_RAW) ? K_RAW :
 541                                  (kbd->kbdmode == VC_MEDIUMRAW) ? K_MEDIUMRAW :
 542                                  (kbd->kbdmode == VC_UNICODE) ? K_UNICODE :
 543                                  K_XLATE);
 544                 goto setint;
 545
 546         /* this could be folded into KDSKBMODE, but for compatibility
 547            reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 548         case KDSKBMETA:
 549                 switch(arg) {
 550                   case K_METABIT:
 551                         clr_vc_kbd_mode(kbd, VC_META);
 552                         break;
 553                   case K_ESCPREFIX:
 554                         set_vc_kbd_mode(kbd, VC_META);
 555                         break;
 556                   default:
 557                         return -EINVAL;
 558                 }
 559                 return 0;
 560
 561         case KDGKBMETA:
 562                 ucval = (vc_kbd_mode(kbd, VC_META) ? K_ESCPREFIX : K_METABIT);
 563         setint:
 564                 return put_user(ucval, (int __user *)arg);
 565
 566         case KDGETKEYCODE:
 567         case KDSETKEYCODE:
 568                 if(!capable(CAP_SYS_TTY_CONFIG))
 569                         perm=0;
 570                 return do_kbkeycode_ioctl(cmd, up, perm);
 571
 572         case KDGKBENT:
 573         case KDSKBENT:
 574                 return do_kdsk_ioctl(cmd, up, perm, kbd);
 575
 576         case KDGKBSENT:
 577         case KDSKBSENT:
 578                 return do_kdgkb_ioctl(cmd, up, perm);
 579
 580         case KDGKBDIACR:
 581         {
 582                 struct kbdiacrs __user *a = up;
 583
 584                 if (put_user(accent_table_size, &a->kb_cnt))
 585                         return -EFAULT;
 586                 if (copy_to_user(a->kbdiacr, accent_table, accent_table_size*sizeof(struct kbdiacr)))
 587                         return -EFAULT;
 588                 return 0;
 589         }
 590
 591         case KDSKBDIACR:
 592         {
 593                 struct kbdiacrs __user *a = up;
 594                 unsigned int ct;
 595
 596                 if (!perm)
 597                         return -EPERM;
 598                 if (get_user(ct,&a->kb_cnt))
 599                         return -EFAULT;
 600                 if (ct >= MAX_DIACR)
 601                         return -EINVAL;
 602                 accent_table_size = ct;
 603                 if (copy_from_user(accent_table, a->kbdiacr, ct*sizeof(struct kbdiacr)))
 604                         return -EFAULT;
 605                 return 0;
 606         }
 607
 608         /* the ioctls below read/set the flags usually shown in the leds */
 609         /* don't use them - they will go away without warning */
 610         case KDGKBLED:
 611                 ucval = kbd->ledflagstate | (kbd->default_ledflagstate << 4);
 612                 goto setchar;
 613
 614         case KDSKBLED:
 615                 if (!perm)
 616                         return -EPERM;
 617                 if (arg & ~0x77)
 618                         return -EINVAL;
 619                 kbd->ledflagstate = (arg & 7);
 620                 kbd->default_ledflagstate = ((arg >> 4) & 7);
 621                 set_leds();
 622                 return 0;
 623
 624         /* the ioctls below only set the lights, not the functions */
 625         /* for those, see KDGKBLED and KDSKBLED above */
 626         case KDGETLED:
 627                 ucval = getledstate();
 628         setchar:
 629                 return put_user(ucval, (char __user *)arg);
 630
 631         case KDSETLED:
 632                 if (!perm)
 633                   return -EPERM;
 634                 setledstate(kbd, arg);
 635                 return 0;
 636
 637         /*
 638          * A process can indicate its willingness to accept signals
 639          * generated by pressing an appropriate key combination.
 640          * Thus, one can have a daemon that e.g. spawns a new console
 641          * upon a keypress and then changes to it.
 642          * See also the kbrequest field of inittab(5).
 643          */
 644         case KDSIGACCEPT:
 645         {
 646                 extern int spawnpid, spawnsig;
 647                 if (!perm || !capable(CAP_KILL))
 648                   return -EPERM;
 649                 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
 650                   return -EINVAL;
 651                 spawnpid = current->pid;
 652                 spawnsig = arg;
 653                 return 0;
 654         }
 655
 656         case VT_SETMODE:
 657         {
 658                 struct vt_mode tmp;
 659
 660                 if (!perm)
 661                         return -EPERM;
 662                 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
 663                         return -EFAULT;
 664                 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
 665                         return -EINVAL;
 666                 acquire_console_sem();
 667                 vc->vt_mode = tmp;
 668                 /* the frsig is ignored, so we set it to 0 */
 669                 vc->vt_mode.frsig = 0;
 670                 vc->vt_pid = current->pid;
 671                 /* no switch is required -- saw@shade.msu.ru */
 672                 vc->vt_newvt = -1;
 673                 release_console_sem();
 674                 return 0;
 675         }
 676
 677         case VT_GETMODE:
 678         {
 679                 struct vt_mode tmp;
 680                 int rc;
 681
 682                 acquire_console_sem();
 683                 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
 684                 release_console_sem();
 685
 686                 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
 687                 return rc ? -EFAULT : 0;
 688         }
 689
 690         /*
 691          * Returns global vt state. Note that VT 0 is always open, since
 692          * it's an alias for the current VT, and people can't use it here.
 693          * We cannot return state for more than 16 VTs, since v_state is short.
 694          */
 695         case VT_GETSTATE:
 696         {
 697                 struct vt_stat __user *vtstat = up;
 698                 unsigned short state, mask;
 699
 700                 if (put_user(fg_console + 1, &vtstat->v_active))
 701                         return -EFAULT;
 702                 state = 1;      /* /dev/tty0 is always open */
 703                 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1)
 704                         if (VT_IS_IN_USE(i))
 705                                 state |= mask;
 706                 return put_user(state, &vtstat->v_state);
 707         }
 708
 709         /*
 710          * Returns the first available (non-opened) console.
 711          */
 712         case VT_OPENQRY:
 713                 for (i = 0; i < MAX_NR_CONSOLES; ++i)
 714                         if (! VT_IS_IN_USE(i))
 715                                 break;
 716                 ucval = i < MAX_NR_CONSOLES ? (i+1) : -1;
 717                 goto setint;
 718
 719         /*
 720          * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
 721          * with num >= 1 (switches to vt 0, our console, are not allowed, just
 722          * to preserve sanity).
 723          */
 724         case VT_ACTIVATE:
 725                 if (!perm)
 726                         return -EPERM;
 727                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 728                         return -ENXIO;
 729                 arg--;
 730                 acquire_console_sem();
 731                 i = vc_allocate(arg);
 732                 release_console_sem();
 733                 if (i)
 734                         return i;
 735                 set_console(arg);
 736                 return 0;
 737
 738         /*
 739          * wait until the specified VT has been activated
 740          */
 741         case VT_WAITACTIVE:
 742                 if (!perm)
 743                         return -EPERM;
 744                 if (arg == 0 || arg > MAX_NR_CONSOLES)
 745                         return -ENXIO;
 746                 return vt_waitactive(arg-1);
 747
 748         /*
 749          * If a vt is under process control, the kernel will not switch to it
 750          * immediately, but postpone the operation until the process calls this
 751          * ioctl, allowing the switch to complete.
 752          *
 753          * According to the X sources this is the behavior:
 754          *      0:      pending switch-from not OK
 755          *      1:      pending switch-from OK
 756          *      2:      completed switch-to OK
 757          */
 758         case VT_RELDISP:
 759                 if (!perm)
 760                         return -EPERM;
 761                 if (vc->vt_mode.mode != VT_PROCESS)
 762                         return -EINVAL;
 763
 764                 /*
 765                  * Switching-from response
 766                  */
 767                 if (vc->vt_newvt >= 0) {
 768                         if (arg == 0)
 769                                 /*
 770                                  * Switch disallowed, so forget we were trying
 771                                  * to do it.
 772                                  */
 773                                 vc->vt_newvt = -1;
 774
 775                         else {
 776                                 /*
 777                                  * The current vt has been released, so
 778                                  * complete the switch.
 779                                  */
 780                                 int newvt;
 781                                 acquire_console_sem();
 782                                 newvt = vc->vt_newvt;
 783                                 vc->vt_newvt = -1;
 784                                 i = vc_allocate(newvt);
 785                                 if (i) {
 786                                         release_console_sem();
 787                                         return i;
 788                                 }
 789                                 /*
 790                                  * When we actually do the console switch,
 791                                  * make sure we are atomic with respect to
 792                                  * other console switches..
 793                                  */
 794                                 complete_change_console(vc_cons[newvt].d);
 795                                 release_console_sem();
 796                         }
 797                 }
 798
 799                 /*
 800                  * Switched-to response
 801                  */
 802                 else
 803                 {
 804                         /*
 805                          * If it's just an ACK, ignore it
 806                          */
 807                         if (arg != VT_ACKACQ)
 808                                 return -EINVAL;
 809                 }
 810
 811                 return 0;
 812
 813          /*
 814           * Disallocate memory associated to VT (but leave VT1)
 815           */
 816          case VT_DISALLOCATE:
 817                 if (arg > MAX_NR_CONSOLES)
 818                         return -ENXIO;
 819                 if (arg == 0) {
 820                     /* disallocate all unused consoles, but leave 0 */
 821                         acquire_console_sem();
 822                         for (i=1; i<MAX_NR_CONSOLES; i++)
 823                                 if (! VT_BUSY(i))
 824                                         vc_disallocate(i);
 825                         release_console_sem();
 826                 } else {
 827                         /* disallocate a single console, if possible */
 828                         arg--;
 829                         if (VT_BUSY(arg))
 830                                 return -EBUSY;
 831                         if (arg) {                            /* leave 0 */
 832                                 acquire_console_sem();
 833                                 vc_disallocate(arg);
 834                                 release_console_sem();
 835                         }
 836                 }
 837                 return 0;
 838
 839         case VT_RESIZE:
 840         {
 841                 struct vt_sizes __user *vtsizes = up;
 842                 ushort ll,cc;
 843                 if (!perm)
 844                         return -EPERM;
 845                 if (get_user(ll, &vtsizes->v_rows) ||
 846                     get_user(cc, &vtsizes->v_cols))
 847                         return -EFAULT;
 848                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 849                         acquire_console_sem();
 850                         vc_resize(vc_cons[i].d, cc, ll);
 851                         release_console_sem();
 852                 }
 853                 return 0;
 854         }
 855
 856         case VT_RESIZEX:
 857         {
 858                 struct vt_consize __user *vtconsize = up;
 859                 ushort ll,cc,vlin,clin,vcol,ccol;
 860                 if (!perm)
 861                         return -EPERM;
 862                 if (!access_ok(VERIFY_READ, vtconsize,
 863                                 sizeof(struct vt_consize)))
 864                         return -EFAULT;
 865                 __get_user(ll, &vtconsize->v_rows);
 866                 __get_user(cc, &vtconsize->v_cols);
 867                 __get_user(vlin, &vtconsize->v_vlin);
 868                 __get_user(clin, &vtconsize->v_clin);
 869                 __get_user(vcol, &vtconsize->v_vcol);
 870                 __get_user(ccol, &vtconsize->v_ccol);
 871                 vlin = vlin ? vlin : vc->vc_scan_lines;
 872                 if (clin) {
 873                         if (ll) {
 874                                 if (ll != vlin/clin)
 875                                         return -EINVAL; /* Parameters don't add up */
 876                         } else
 877                                 ll = vlin/clin;
 878                 }
 879                 if (vcol && ccol) {
 880                         if (cc) {
 881                                 if (cc != vcol/ccol)
 882                                         return -EINVAL;
 883                         } else
 884                                 cc = vcol/ccol;
 885                 }
 886
 887                 if (clin > 32)
 888                         return -EINVAL;
 889
 890                 for (i = 0; i < MAX_NR_CONSOLES; i++) {
 891                         if (!vc_cons[i].d)
 892                                 continue;
 893                         acquire_console_sem();
 894                         if (vlin)
 895                                 vc_cons[i].d->vc_scan_lines = vlin;
 896                         if (clin)
 897                                 vc_cons[i].d->vc_font.height = clin;
 898                         vc_resize(vc_cons[i].d, cc, ll);
 899                         release_console_sem();
 900                 }
 901                 return 0;
 902         }
 903
 904         case PIO_FONT: {
 905                 if (!perm)
 906                         return -EPERM;
 907                 op.op = KD_FONT_OP_SET;
 908                 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
 909                 op.width = 8;
 910                 op.height = 0;
 911                 op.charcount = 256;
 912                 op.data = up;
 913                 return con_font_op(vc_cons[fg_console].d, &op);
 914         }
 915
 916         case GIO_FONT: {
 917                 op.op = KD_FONT_OP_GET;
 918                 op.flags = KD_FONT_FLAG_OLD;
 919                 op.width = 8;
 920                 op.height = 32;
 921                 op.charcount = 256;
 922                 op.data = up;
 923                 return con_font_op(vc_cons[fg_console].d, &op);
 924         }
 925
 926         case PIO_CMAP:
 927                 if (!perm)
 928                         return -EPERM;
 929                 return con_set_cmap(up);
 930
 931         case GIO_CMAP:
 932                 return con_get_cmap(up);
 933
 934         case PIO_FONTX:
 935         case GIO_FONTX:
 936                 return do_fontx_ioctl(cmd, up, perm, &op);
 937
 938         case PIO_FONTRESET:
 939         {
 940                 if (!perm)
 941                         return -EPERM;
 942
 943 #ifdef BROKEN_GRAPHICS_PROGRAMS
 944                 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
 945                    font is not saved. */
 946                 return -ENOSYS;
 947 #else
 948                 {
 949                 op.op = KD_FONT_OP_SET_DEFAULT;
 950                 op.data = NULL;
 951                 i = con_font_op(vc_cons[fg_console].d, &op);
 952                 if (i)
 953                         return i;
 954                 con_set_default_unimap(vc_cons[fg_console].d);
 955                 return 0;
 956                 }
 957 #endif
 958         }
 959
 960         case KDFONTOP: {
 961                 if (copy_from_user(&op, up, sizeof(op)))
 962                         return -EFAULT;
 963                 if (!perm && op.op != KD_FONT_OP_GET)
 964                         return -EPERM;
 965                 i = con_font_op(vc, &op);
 966                 if (i) return i;
 967                 if (copy_to_user(up, &op, sizeof(op)))
 968                         return -EFAULT;
 969                 return 0;
 970         }
 971
 972         case PIO_SCRNMAP:
 973                 if (!perm)
 974                         return -EPERM;
 975                 return con_set_trans_old(up);
 976
 977         case GIO_SCRNMAP:
 978                 return con_get_trans_old(up);
 979
 980         case PIO_UNISCRNMAP:
 981                 if (!perm)
 982                         return -EPERM;
 983                 return con_set_trans_new(up);
 984
 985         case GIO_UNISCRNMAP:
 986                 return con_get_trans_new(up);
 987
 988         case PIO_UNIMAPCLR:
 989               { struct unimapinit ui;
 990                 if (!perm)
 991                         return -EPERM;
 992                 i = copy_from_user(&ui, up, sizeof(struct unimapinit));
 993                 if (i) return -EFAULT;
 994                 con_clear_unimap(vc, &ui);
 995                 return 0;
 996               }
 997
 998         case PIO_UNIMAP:
 999         case GIO_UNIMAP:
1000                 return do_unimap_ioctl(cmd, up, perm, vc);
1001
1002         case VT_LOCKSWITCH:
1003                 if (!capable(CAP_SYS_TTY_CONFIG))
1004                    return -EPERM;
1005                 vt_dont_switch = 1;
1006                 return 0;
1007         case VT_UNLOCKSWITCH:
1008                 if (!capable(CAP_SYS_TTY_CONFIG))
1009                    return -EPERM;
1010                 vt_dont_switch = 0;
1011                 return 0;
1012         default:
1013                 return -ENOIOCTLCMD;
1014         }
1015 }
1016
1017 /*
1018  * Sometimes we want to wait until a particular VT has been activated. We
1019  * do it in a very simple manner. Everybody waits on a single queue and
1020  * get woken up at once. Those that are satisfied go on with their business,
1021  * while those not ready go back to sleep. Seems overkill to add a wait
1022  * to each vt just for this - usually this does nothing!
1023  */
1024 static DECLARE_WAIT_QUEUE_HEAD(vt_activate_queue);
1025
1026 /*
1027  * Sleeps until a vt is activated, or the task is interrupted. Returns
1028  * 0 if activation, -EINTR if interrupted.
1029  */
1030 int vt_waitactive(int vt)
1031 {
1032         int retval;
1033         DECLARE_WAITQUEUE(wait, current);
1034
1035         add_wait_queue(&vt_activate_queue, &wait);
1036         for (;;) {
1037                 set_current_state(TASK_INTERRUPTIBLE);
1038                 retval = 0;
1039                 if (vt == fg_console)
1040                         break;
1041                 retval = -EINTR;
1042                 if (signal_pending(current))
1043                         break;
1044                 schedule();
1045         }
1046         remove_wait_queue(&vt_activate_queue, &wait);
1047         current->state = TASK_RUNNING;
1048         return retval;
1049 }
1050
1051 #define vt_wake_waitactive() wake_up(&vt_activate_queue)
1052
1053 void reset_vc(struct vc_data *vc)
1054 {
1055         vc->vc_mode = KD_TEXT;
1056         kbd_table[vc->vc_num].kbdmode = VC_XLATE;
1057         vc->vt_mode.mode = VT_AUTO;
1058         vc->vt_mode.waitv = 0;
1059         vc->vt_mode.relsig = 0;
1060         vc->vt_mode.acqsig = 0;
1061         vc->vt_mode.frsig = 0;
1062         vc->vt_pid = -1;
1063         vc->vt_newvt = -1;
1064         if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
1065                 reset_palette(vc);
1066 }
1067
1068 /*
1069  * Performs the back end of a vt switch
1070  */
1071 static void complete_change_console(struct vc_data *vc)
1072 {
1073         unsigned char old_vc_mode;
1074
1075         last_console = fg_console;
1076
1077         /*
1078          * If we're switching, we could be going from KD_GRAPHICS to
1079          * KD_TEXT mode or vice versa, which means we need to blank or
1080          * unblank the screen later.
1081          */
1082         old_vc_mode = vc_cons[fg_console].d->vc_mode;
1083         switch_screen(vc);
1084
1085         /*
1086          * This can't appear below a successful kill_proc().  If it did,
1087          * then the *blank_screen operation could occur while X, having
1088          * received acqsig, is waking up on another processor.  This
1089          * condition can lead to overlapping accesses to the VGA range
1090          * and the framebuffer (causing system lockups).
1091          *
1092          * To account for this we duplicate this code below only if the
1093          * controlling process is gone and we've called reset_vc.
1094          */
1095         if (old_vc_mode != vc->vc_mode) {
1096                 if (vc->vc_mode == KD_TEXT)
1097                         do_unblank_screen(1);
1098                 else
1099                         do_blank_screen(1);
1100         }
1101
1102         /*
1103          * If this new console is under process control, send it a signal
1104          * telling it that it has acquired. Also check if it has died and
1105          * clean up (similar to logic employed in change_console())
1106          */
1107         if (vc->vt_mode.mode == VT_PROCESS) {
1108                 /*
1109                  * Send the signal as privileged - kill_proc() will
1110                  * tell us if the process has gone or something else
1111                  * is awry
1112                  */
1113                 if (kill_proc(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1114                 /*
1115                  * The controlling process has died, so we revert back to
1116                  * normal operation. In this case, we'll also change back
1117                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1118                  * but it saves the agony when the X server dies and the screen
1119                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1120                  * this outside of VT_PROCESS but there is no single process
1121                  * to account for and tracking tty count may be undesirable.
1122                  */
1123                         reset_vc(vc);
1124
1125                         if (old_vc_mode != vc->vc_mode) {
1126                                 if (vc->vc_mode == KD_TEXT)
1127                                         do_unblank_screen(1);
1128                                 else
1129                                         do_blank_screen(1);
1130                         }
1131                 }
1132         }
1133
1134         /*
1135          * Wake anyone waiting for their VT to activate
1136          */
1137         vt_wake_waitactive();
1138         return;
1139 }
1140
1141 /*
1142  * Performs the front-end of a vt switch
1143  */
1144 void change_console(struct vc_data *new_vc)
1145 {
1146         struct vc_data *vc;
1147
1148         if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1149                 return;
1150
1151         /*
1152          * If this vt is in process mode, then we need to handshake with
1153          * that process before switching. Essentially, we store where that
1154          * vt wants to switch to and wait for it to tell us when it's done
1155          * (via VT_RELDISP ioctl).
1156          *
1157          * We also check to see if the controlling process still exists.
1158          * If it doesn't, we reset this vt to auto mode and continue.
1159          * This is a cheap way to track process control. The worst thing
1160          * that can happen is: we send a signal to a process, it dies, and
1161          * the switch gets "lost" waiting for a response; hopefully, the
1162          * user will try again, we'll detect the process is gone (unless
1163          * the user waits just the right amount of time :-) and revert the
1164          * vt to auto control.
1165          */
1166         vc = vc_cons[fg_console].d;
1167         if (vc->vt_mode.mode == VT_PROCESS) {
1168                 /*
1169                  * Send the signal as privileged - kill_proc() will
1170                  * tell us if the process has gone or something else
1171                  * is awry
1172                  */
1173                 if (kill_proc(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1174                         /*
1175                          * It worked. Mark the vt to switch to and
1176                          * return. The process needs to send us a
1177                          * VT_RELDISP ioctl to complete the switch.
1178                          */
1179                         vc->vt_newvt = new_vc->vc_num;
1180                         return;
1181                 }
1182
1183                 /*
1184                  * The controlling process has died, so we revert back to
1185                  * normal operation. In this case, we'll also change back
1186                  * to KD_TEXT mode. I'm not sure if this is strictly correct
1187                  * but it saves the agony when the X server dies and the screen
1188                  * remains blanked due to KD_GRAPHICS! It would be nice to do
1189                  * this outside of VT_PROCESS but there is no single process
1190                  * to account for and tracking tty count may be undesirable.
1191                  */
1192                 reset_vc(vc);
1193
1194                 /*
1195                  * Fall through to normal (VT_AUTO) handling of the switch...
1196                  */
1197         }
1198
1199         /*
1200          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1201          */
1202         if (vc->vc_mode == KD_GRAPHICS)
1203                 return;
1204
1205         complete_change_console(new_vc);
1206 }