drivers/tty/vt/vc_screen.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Provide access to virtual console memory.
   4  * /dev/vcs: the screen as it is being viewed right now (possibly scrolled)
   5  * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
   6  *            [minor: N]
   7  *
   8  * /dev/vcsaN: idem, but including attributes, and prefixed with
   9  *      the 4 bytes lines,columns,x,y (as screendump used to give).
  10  *      Attribute/character pair is in native endianity.
  11  *            [minor: N+128]
  12  *
  13  * /dev/vcsuN: similar to /dev/vcsaN but using 4-byte unicode values
  14  *      instead of 1-byte screen glyph values.
  15  *            [minor: N+64]
  16  *
  17  * /dev/vcsuaN: same idea as /dev/vcsaN for unicode (not yet implemented).
  18  *
  19  * This replaces screendump and part of selection, so that the system
  20  * administrator can control access using file system permissions.
  21  *
  22  * aeb@cwi.nl - efter Friedas begravelse - 950211
  23  *
  24  * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
  25  *       - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
  26  *       - making it shorter - scr_readw are macros which expand in PRETTY long code
  27  */
  28
  29 #include <linux/kernel.h>
  30 #include <linux/major.h>
  31 #include <linux/errno.h>
  32 #include <linux/export.h>
  33 #include <linux/tty.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/mm.h>
  36 #include <linux/init.h>
  37 #include <linux/vt_kern.h>
  38 #include <linux/selection.h>
  39 #include <linux/kbd_kern.h>
  40 #include <linux/console.h>
  41 #include <linux/device.h>
  42 #include <linux/sched.h>
  43 #include <linux/fs.h>
  44 #include <linux/poll.h>
  45 #include <linux/signal.h>
  46 #include <linux/slab.h>
  47 #include <linux/notifier.h>
  48
  49 #include <linux/uaccess.h>
  50 #include <asm/byteorder.h>
  51 #include <asm/unaligned.h>
  52
  53 #undef attr
  54 #undef org
  55 #undef addr
  56 #define HEADER_SIZE     4
  57
  58 #define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
  59
  60 /*
  61  * Our minor space:
  62  *
  63  *   0 ... 63   glyph mode without attributes
  64  *  64 ... 127  unicode mode without attributes
  65  * 128 ... 191  glyph mode with attributes
  66  * 192 ... 255  unused (reserved for unicode with attributes)
  67  *
  68  * This relies on MAX_NR_CONSOLES being  <= 63, meaning 63 actual consoles
  69  * with minors 0, 64, 128 and 192 being proxies for the foreground console.
  70  */
  71 #if MAX_NR_CONSOLES > 63
  72 #warning "/dev/vcs* devices may not accommodate more than 63 consoles"
  73 #endif
  74
  75 #define console(inode)          (iminor(inode) & 63)
  76 #define use_unicode(inode)      (iminor(inode) & 64)
  77 #define use_attributes(inode)   (iminor(inode) & 128)
  78
  79
  80 struct vcs_poll_data {
  81         struct notifier_block notifier;
  82         unsigned int cons_num;
  83         int event;
  84         wait_queue_head_t waitq;
  85         struct fasync_struct *fasync;
  86 };
  87
  88 static int
  89 vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
  90 {
  91         struct vt_notifier_param *param = _param;
  92         struct vc_data *vc = param->vc;
  93         struct vcs_poll_data *poll =
  94                 container_of(nb, struct vcs_poll_data, notifier);
  95         int currcons = poll->cons_num;
  96         int fa_band;
  97
  98         switch (code) {
  99         case VT_UPDATE:
 100                 fa_band = POLL_PRI;
 101                 break;
 102         case VT_DEALLOCATE:
 103                 fa_band = POLL_HUP;
 104                 break;
 105         default:
 106                 return NOTIFY_DONE;
 107         }
 108
 109         if (currcons == 0)
 110                 currcons = fg_console;
 111         else
 112                 currcons--;
 113         if (currcons != vc->vc_num)
 114                 return NOTIFY_DONE;
 115
 116         poll->event = code;
 117         wake_up_interruptible(&poll->waitq);
 118         kill_fasync(&poll->fasync, SIGIO, fa_band);
 119         return NOTIFY_OK;
 120 }
 121
 122 static void
 123 vcs_poll_data_free(struct vcs_poll_data *poll)
 124 {
 125         unregister_vt_notifier(&poll->notifier);
 126         kfree(poll);
 127 }
 128
 129 static struct vcs_poll_data *
 130 vcs_poll_data_get(struct file *file)
 131 {
 132         struct vcs_poll_data *poll = file->private_data, *kill = NULL;
 133
 134         if (poll)
 135                 return poll;
 136
 137         poll = kzalloc(sizeof(*poll), GFP_KERNEL);
 138         if (!poll)
 139                 return NULL;
 140         poll->cons_num = console(file_inode(file));
 141         init_waitqueue_head(&poll->waitq);
 142         poll->notifier.notifier_call = vcs_notifier;
 143         /*
 144          * In order not to lose any update event, we must pretend one might
 145          * have occurred before we have a chance to register our notifier.
 146          * This is also how user space has come to detect which kernels
 147          * support POLLPRI on /dev/vcs* devices i.e. using poll() with
 148          * POLLPRI and a zero timeout.
 149          */
 150         poll->event = VT_UPDATE;
 151
 152         if (register_vt_notifier(&poll->notifier) != 0) {
 153                 kfree(poll);
 154                 return NULL;
 155         }
 156
 157         /*
 158          * This code may be called either through ->poll() or ->fasync().
 159          * If we have two threads using the same file descriptor, they could
 160          * both enter this function, both notice that the structure hasn't
 161          * been allocated yet and go ahead allocating it in parallel, but
 162          * only one of them must survive and be shared otherwise we'd leak
 163          * memory with a dangling notifier callback.
 164          */
 165         spin_lock(&file->f_lock);
 166         if (!file->private_data) {
 167                 file->private_data = poll;
 168         } else {
 169                 /* someone else raced ahead of us */
 170                 kill = poll;
 171                 poll = file->private_data;
 172         }
 173         spin_unlock(&file->f_lock);
 174         if (kill)
 175                 vcs_poll_data_free(kill);
 176
 177         return poll;
 178 }
 179
 180 /*
 181  * Returns VC for inode.
 182  * Must be called with console_lock.
 183  */
 184 static struct vc_data*
 185 vcs_vc(struct inode *inode, int *viewed)
 186 {
 187         unsigned int currcons = console(inode);
 188
 189         WARN_CONSOLE_UNLOCKED();
 190
 191         if (currcons == 0) {
 192                 currcons = fg_console;
 193                 if (viewed)
 194                         *viewed = 1;
 195         } else {
 196                 currcons--;
 197                 if (viewed)
 198                         *viewed = 0;
 199         }
 200         return vc_cons[currcons].d;
 201 }
 202
 203 /*
 204  * Returns size for VC carried by inode.
 205  * Must be called with console_lock.
 206  */
 207 static int
 208 vcs_size(struct inode *inode)
 209 {
 210         int size;
 211         struct vc_data *vc;
 212
 213         WARN_CONSOLE_UNLOCKED();
 214
 215         vc = vcs_vc(inode, NULL);
 216         if (!vc)
 217                 return -ENXIO;
 218
 219         size = vc->vc_rows * vc->vc_cols;
 220
 221         if (use_attributes(inode)) {
 222                 if (use_unicode(inode))
 223                         return -EOPNOTSUPP;
 224                 size = 2*size + HEADER_SIZE;
 225         } else if (use_unicode(inode))
 226                 size *= 4;
 227         return size;
 228 }
 229
 230 static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
 231 {
 232         int size;
 233
 234         console_lock();
 235         size = vcs_size(file_inode(file));
 236         console_unlock();
 237         if (size < 0)
 238                 return size;
 239         return fixed_size_llseek(file, offset, orig, size);
 240 }
 241
 242
 243 static ssize_t
 244 vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 245 {
 246         struct inode *inode = file_inode(file);
 247         struct vc_data *vc;
 248         struct vcs_poll_data *poll;
 249         long pos, read;
 250         int attr, uni_mode, row, col, maxcol, viewed;
 251         unsigned short *org = NULL;
 252         ssize_t ret;
 253         char *con_buf;
 254
 255         con_buf = (char *) __get_free_page(GFP_KERNEL);
 256         if (!con_buf)
 257                 return -ENOMEM;
 258
 259         pos = *ppos;
 260
 261         /* Select the proper current console and verify
 262          * sanity of the situation under the console lock.
 263          */
 264         console_lock();
 265
 266         uni_mode = use_unicode(inode);
 267         attr = use_attributes(inode);
 268         ret = -ENXIO;
 269         vc = vcs_vc(inode, &viewed);
 270         if (!vc)
 271                 goto unlock_out;
 272
 273         ret = -EINVAL;
 274         if (pos < 0)
 275                 goto unlock_out;
 276         /* we enforce 32-bit alignment for pos and count in unicode mode */
 277         if (uni_mode && (pos | count) & 3)
 278                 goto unlock_out;
 279
 280         poll = file->private_data;
 281         if (count && poll)
 282                 poll->event = 0;
 283         read = 0;
 284         ret = 0;
 285         while (count) {
 286                 char *con_buf0, *con_buf_start;
 287                 long this_round, size;
 288                 ssize_t orig_count;
 289                 long p = pos;
 290
 291                 /* Check whether we are above size each round,
 292                  * as copy_to_user at the end of this loop
 293                  * could sleep.
 294                  */
 295                 size = vcs_size(inode);
 296                 if (size < 0) {
 297                         if (read)
 298                                 break;
 299                         ret = size;
 300                         goto unlock_out;
 301                 }
 302                 if (pos >= size)
 303                         break;
 304                 if (count > size - pos)
 305                         count = size - pos;
 306
 307                 this_round = count;
 308                 if (this_round > CON_BUF_SIZE)
 309                         this_round = CON_BUF_SIZE;
 310
 311                 /* Perform the whole read into the local con_buf.
 312                  * Then we can drop the console spinlock and safely
 313                  * attempt to move it to userspace.
 314                  */
 315
 316                 con_buf_start = con_buf0 = con_buf;
 317                 orig_count = this_round;
 318                 maxcol = vc->vc_cols;
 319                 if (uni_mode) {
 320                         unsigned int nr;
 321
 322                         ret = vc_uniscr_check(vc);
 323                         if (ret)
 324                                 break;
 325                         p /= 4;
 326                         row = p / vc->vc_cols;
 327                         col = p % maxcol;
 328                         nr = maxcol - col;
 329                         do {
 330                                 if (nr > this_round/4)
 331                                         nr = this_round/4;
 332                                 vc_uniscr_copy_line(vc, con_buf0, viewed,
 333                                                     row, col, nr);
 334                                 con_buf0 += nr * 4;
 335                                 this_round -= nr * 4;
 336                                 row++;
 337                                 col = 0;
 338                                 nr = maxcol;
 339                         } while (this_round);
 340                 } else if (!attr) {
 341                         org = screen_pos(vc, p, viewed);
 342                         col = p % maxcol;
 343                         p += maxcol - col;
 344                         while (this_round-- > 0) {
 345                                 *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
 346                                 if (++col == maxcol) {
 347                                         org = screen_pos(vc, p, viewed);
 348                                         col = 0;
 349                                         p += maxcol;
 350                                 }
 351                         }
 352                 } else {
 353                         if (p < HEADER_SIZE) {
 354                                 size_t tmp_count;
 355
 356                                 /* clamp header values if they don't fit */
 357                                 con_buf0[0] = min(vc->vc_rows, 0xFFu);
 358                                 con_buf0[1] = min(vc->vc_cols, 0xFFu);
 359                                 getconsxy(vc, con_buf0 + 2);
 360
 361                                 con_buf_start += p;
 362                                 this_round += p;
 363                                 if (this_round > CON_BUF_SIZE) {
 364                                         this_round = CON_BUF_SIZE;
 365                                         orig_count = this_round - p;
 366                                 }
 367
 368                                 tmp_count = HEADER_SIZE;
 369                                 if (tmp_count > this_round)
 370                                         tmp_count = this_round;
 371
 372                                 /* Advance state pointers and move on. */
 373                                 this_round -= tmp_count;
 374                                 p = HEADER_SIZE;
 375                                 con_buf0 = con_buf + HEADER_SIZE;
 376                                 /* If this_round >= 0, then p is even... */
 377                         } else if (p & 1) {
 378                                 /* Skip first byte for output if start address is odd
 379                                  * Update region sizes up/down depending on free
 380                                  * space in buffer.
 381                                  */
 382                                 con_buf_start++;
 383                                 if (this_round < CON_BUF_SIZE)
 384                                         this_round++;
 385                                 else
 386                                         orig_count--;
 387                         }
 388                         if (this_round > 0) {
 389                                 unsigned short *tmp_buf = (unsigned short *)con_buf0;
 390
 391                                 p -= HEADER_SIZE;
 392                                 p /= 2;
 393                                 col = p % maxcol;
 394
 395                                 org = screen_pos(vc, p, viewed);
 396                                 p += maxcol - col;
 397
 398                                 /* Buffer has even length, so we can always copy
 399                                  * character + attribute. We do not copy last byte
 400                                  * to userspace if this_round is odd.
 401                                  */
 402                                 this_round = (this_round + 1) >> 1;
 403
 404                                 while (this_round) {
 405                                         *tmp_buf++ = vcs_scr_readw(vc, org++);
 406                                         this_round --;
 407                                         if (++col == maxcol) {
 408                                                 org = screen_pos(vc, p, viewed);
 409                                                 col = 0;
 410                                                 p += maxcol;
 411                                         }
 412                                 }
 413                         }
 414                 }
 415
 416                 /* Finally, release the console semaphore while we push
 417                  * all the data to userspace from our temporary buffer.
 418                  *
 419                  * AKPM: Even though it's a semaphore, we should drop it because
 420                  * the pagefault handling code may want to call printk().
 421                  */
 422
 423                 console_unlock();
 424                 ret = copy_to_user(buf, con_buf_start, orig_count);
 425                 console_lock();
 426
 427                 if (ret) {
 428                         read += (orig_count - ret);
 429                         ret = -EFAULT;
 430                         break;
 431                 }
 432                 buf += orig_count;
 433                 pos += orig_count;
 434                 read += orig_count;
 435                 count -= orig_count;
 436         }
 437         *ppos += read;
 438         if (read)
 439                 ret = read;
 440 unlock_out:
 441         console_unlock();
 442         free_page((unsigned long) con_buf);
 443         return ret;
 444 }
 445
 446 static ssize_t
 447 vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 448 {
 449         struct inode *inode = file_inode(file);
 450         struct vc_data *vc;
 451         long pos;
 452         long attr, size, written;
 453         char *con_buf0;
 454         int col, maxcol, viewed;
 455         u16 *org0 = NULL, *org = NULL;
 456         size_t ret;
 457         char *con_buf;
 458
 459         if (use_unicode(inode))
 460                 return -EOPNOTSUPP;
 461
 462         con_buf = (char *) __get_free_page(GFP_KERNEL);
 463         if (!con_buf)
 464                 return -ENOMEM;
 465
 466         pos = *ppos;
 467
 468         /* Select the proper current console and verify
 469          * sanity of the situation under the console lock.
 470          */
 471         console_lock();
 472
 473         attr = use_attributes(inode);
 474         ret = -ENXIO;
 475         vc = vcs_vc(inode, &viewed);
 476         if (!vc)
 477                 goto unlock_out;
 478
 479         size = vcs_size(inode);
 480         ret = -EINVAL;
 481         if (pos < 0 || pos > size)
 482                 goto unlock_out;
 483         if (count > size - pos)
 484                 count = size - pos;
 485         written = 0;
 486         while (count) {
 487                 long this_round = count;
 488                 size_t orig_count;
 489                 long p;
 490
 491                 if (this_round > CON_BUF_SIZE)
 492                         this_round = CON_BUF_SIZE;
 493
 494                 /* Temporarily drop the console lock so that we can read
 495                  * in the write data from userspace safely.
 496                  */
 497                 console_unlock();
 498                 ret = copy_from_user(con_buf, buf, this_round);
 499                 console_lock();
 500
 501                 if (ret) {
 502                         this_round -= ret;
 503                         if (!this_round) {
 504                                 /* Abort loop if no data were copied. Otherwise
 505                                  * fail with -EFAULT.
 506                                  */
 507                                 if (written)
 508                                         break;
 509                                 ret = -EFAULT;
 510                                 goto unlock_out;
 511                         }
 512                 }
 513
 514                 /* The vcs_size might have changed while we slept to grab
 515                  * the user buffer, so recheck.
 516                  * Return data written up to now on failure.
 517                  */
 518                 size = vcs_size(inode);
 519                 if (size < 0) {
 520                         if (written)
 521                                 break;
 522                         ret = size;
 523                         goto unlock_out;
 524                 }
 525                 if (pos >= size)
 526                         break;
 527                 if (this_round > size - pos)
 528                         this_round = size - pos;
 529
 530                 /* OK, now actually push the write to the console
 531                  * under the lock using the local kernel buffer.
 532                  */
 533
 534                 con_buf0 = con_buf;
 535                 orig_count = this_round;
 536                 maxcol = vc->vc_cols;
 537                 p = pos;
 538                 if (!attr) {
 539                         org0 = org = screen_pos(vc, p, viewed);
 540                         col = p % maxcol;
 541                         p += maxcol - col;
 542
 543                         while (this_round > 0) {
 544                                 unsigned char c = *con_buf0++;
 545
 546                                 this_round--;
 547                                 vcs_scr_writew(vc,
 548                                                (vcs_scr_readw(vc, org) & 0xff00) | c, org);
 549                                 org++;
 550                                 if (++col == maxcol) {
 551                                         org = screen_pos(vc, p, viewed);
 552                                         col = 0;
 553                                         p += maxcol;
 554                                 }
 555                         }
 556                 } else {
 557                         if (p < HEADER_SIZE) {
 558                                 char header[HEADER_SIZE];
 559
 560                                 getconsxy(vc, header + 2);
 561                                 while (p < HEADER_SIZE && this_round > 0) {
 562                                         this_round--;
 563                                         header[p++] = *con_buf0++;
 564                                 }
 565                                 if (!viewed)
 566                                         putconsxy(vc, header + 2);
 567                         }
 568                         p -= HEADER_SIZE;
 569                         col = (p/2) % maxcol;
 570                         if (this_round > 0) {
 571                                 org0 = org = screen_pos(vc, p/2, viewed);
 572                                 if ((p & 1) && this_round > 0) {
 573                                         char c;
 574
 575                                         this_round--;
 576                                         c = *con_buf0++;
 577 #ifdef __BIG_ENDIAN
 578                                         vcs_scr_writew(vc, c |
 579                                              (vcs_scr_readw(vc, org) & 0xff00), org);
 580 #else
 581                                         vcs_scr_writew(vc, (c << 8) |
 582                                              (vcs_scr_readw(vc, org) & 0xff), org);
 583 #endif
 584                                         org++;
 585                                         p++;
 586                                         if (++col == maxcol) {
 587                                                 org = screen_pos(vc, p/2, viewed);
 588                                                 col = 0;
 589                                         }
 590                                 }
 591                                 p /= 2;
 592                                 p += maxcol - col;
 593                         }
 594                         while (this_round > 1) {
 595                                 unsigned short w;
 596
 597                                 w = get_unaligned(((unsigned short *)con_buf0));
 598                                 vcs_scr_writew(vc, w, org++);
 599                                 con_buf0 += 2;
 600                                 this_round -= 2;
 601                                 if (++col == maxcol) {
 602                                         org = screen_pos(vc, p, viewed);
 603                                         col = 0;
 604                                         p += maxcol;
 605                                 }
 606                         }
 607                         if (this_round > 0) {
 608                                 unsigned char c;
 609
 610                                 c = *con_buf0++;
 611 #ifdef __BIG_ENDIAN
 612                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
 613 #else
 614                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
 615 #endif
 616                         }
 617                 }
 618                 count -= orig_count;
 619                 written += orig_count;
 620                 buf += orig_count;
 621                 pos += orig_count;
 622                 if (org0)
 623                         update_region(vc, (unsigned long)(org0), org - org0);
 624         }
 625         *ppos += written;
 626         ret = written;
 627         if (written)
 628                 vcs_scr_updated(vc);
 629
 630 unlock_out:
 631         console_unlock();
 632         free_page((unsigned long) con_buf);
 633         return ret;
 634 }
 635
 636 static __poll_t
 637 vcs_poll(struct file *file, poll_table *wait)
 638 {
 639         struct vcs_poll_data *poll = vcs_poll_data_get(file);
 640         __poll_t ret = DEFAULT_POLLMASK|EPOLLERR;
 641
 642         if (poll) {
 643                 poll_wait(file, &poll->waitq, wait);
 644                 switch (poll->event) {
 645                 case VT_UPDATE:
 646                         ret = DEFAULT_POLLMASK|EPOLLPRI;
 647                         break;
 648                 case VT_DEALLOCATE:
 649                         ret = DEFAULT_POLLMASK|EPOLLHUP|EPOLLERR;
 650                         break;
 651                 case 0:
 652                         ret = DEFAULT_POLLMASK;
 653                         break;
 654                 }
 655         }
 656         return ret;
 657 }
 658
 659 static int
 660 vcs_fasync(int fd, struct file *file, int on)
 661 {
 662         struct vcs_poll_data *poll = file->private_data;
 663
 664         if (!poll) {
 665                 /* don't allocate anything if all we want is disable fasync */
 666                 if (!on)
 667                         return 0;
 668                 poll = vcs_poll_data_get(file);
 669                 if (!poll)
 670                         return -ENOMEM;
 671         }
 672
 673         return fasync_helper(fd, file, on, &poll->fasync);
 674 }
 675
 676 static int
 677 vcs_open(struct inode *inode, struct file *filp)
 678 {
 679         unsigned int currcons = console(inode);
 680         bool attr = use_attributes(inode);
 681         bool uni_mode = use_unicode(inode);
 682         int ret = 0;
 683
 684         /* we currently don't support attributes in unicode mode */
 685         if (attr && uni_mode)
 686                 return -EOPNOTSUPP;
 687
 688         console_lock();
 689         if(currcons && !vc_cons_allocated(currcons-1))
 690                 ret = -ENXIO;
 691         console_unlock();
 692         return ret;
 693 }
 694
 695 static int vcs_release(struct inode *inode, struct file *file)
 696 {
 697         struct vcs_poll_data *poll = file->private_data;
 698
 699         if (poll)
 700                 vcs_poll_data_free(poll);
 701         return 0;
 702 }
 703
 704 static const struct file_operations vcs_fops = {
 705         .llseek         = vcs_lseek,
 706         .read           = vcs_read,
 707         .write          = vcs_write,
 708         .poll           = vcs_poll,
 709         .fasync         = vcs_fasync,
 710         .open           = vcs_open,
 711         .release        = vcs_release,
 712 };
 713
 714 static struct class *vc_class;
 715
 716 void vcs_make_sysfs(int index)
 717 {
 718         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
 719                       "vcs%u", index + 1);
 720         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 65), NULL,
 721                       "vcsu%u", index + 1);
 722         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
 723                       "vcsa%u", index + 1);
 724 }
 725
 726 void vcs_remove_sysfs(int index)
 727 {
 728         device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
 729         device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 65));
 730         device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
 731 }
 732
 733 int __init vcs_init(void)
 734 {
 735         unsigned int i;
 736
 737         if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
 738                 panic("unable to get major %d for vcs device", VCS_MAJOR);
 739         vc_class = class_create(THIS_MODULE, "vc");
 740
 741         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
 742         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 64), NULL, "vcsu");
 743         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
 744         for (i = 0; i < MIN_NR_CONSOLES; i++)
 745                 vcs_make_sysfs(i);
 746         return 0;
 747 }