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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
80struct 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
88static int
89vcs_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
122static void
123vcs_poll_data_free(struct vcs_poll_data *poll)
124{
125 unregister_vt_notifier(&poll->notifier);
126 kfree(poll);
127}
128
129static struct vcs_poll_data *
130vcs_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 */
184static struct vc_data*
185vcs_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 */
207static int
208vcs_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
230static 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
243static ssize_t
244vcs_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;
440unlock_out:
441 console_unlock();
442 free_page((unsigned long) con_buf);
443 return ret;
444}
445
446static ssize_t
447vcs_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 con_buf = (char *) __get_free_page(GFP_KERNEL);
460 if (!con_buf)
461 return -ENOMEM;
462
463 pos = *ppos;
464
465 /* Select the proper current console and verify
466 * sanity of the situation under the console lock.
467 */
468 console_lock();
469
470 attr = use_attributes(inode);
471 ret = -ENXIO;
472 vc = vcs_vc(inode, &viewed);
473 if (!vc)
474 goto unlock_out;
475
476 size = vcs_size(inode);
477 ret = -EINVAL;
478 if (pos < 0 || pos > size)
479 goto unlock_out;
480 if (count > size - pos)
481 count = size - pos;
482 written = 0;
483 while (count) {
484 long this_round = count;
485 size_t orig_count;
486 long p;
487
488 if (this_round > CON_BUF_SIZE)
489 this_round = CON_BUF_SIZE;
490
491 /* Temporarily drop the console lock so that we can read
492 * in the write data from userspace safely.
493 */
494 console_unlock();
495 ret = copy_from_user(con_buf, buf, this_round);
496 console_lock();
497
498 if (ret) {
499 this_round -= ret;
500 if (!this_round) {
501 /* Abort loop if no data were copied. Otherwise
502 * fail with -EFAULT.
503 */
504 if (written)
505 break;
506 ret = -EFAULT;
507 goto unlock_out;
508 }
509 }
510
511 /* The vcs_size might have changed while we slept to grab
512 * the user buffer, so recheck.
513 * Return data written up to now on failure.
514 */
515 size = vcs_size(inode);
516 if (size < 0) {
517 if (written)
518 break;
519 ret = size;
520 goto unlock_out;
521 }
522 if (pos >= size)
523 break;
524 if (this_round > size - pos)
525 this_round = size - pos;
526
527 /* OK, now actually push the write to the console
528 * under the lock using the local kernel buffer.
529 */
530
531 con_buf0 = con_buf;
532 orig_count = this_round;
533 maxcol = vc->vc_cols;
534 p = pos;
535 if (!attr) {
536 org0 = org = screen_pos(vc, p, viewed);
537 col = p % maxcol;
538 p += maxcol - col;
539
540 while (this_round > 0) {
541 unsigned char c = *con_buf0++;
542
543 this_round--;
544 vcs_scr_writew(vc,
545 (vcs_scr_readw(vc, org) & 0xff00) | c, org);
546 org++;
547 if (++col == maxcol) {
548 org = screen_pos(vc, p, viewed);
549 col = 0;
550 p += maxcol;
551 }
552 }
553 } else {
554 if (p < HEADER_SIZE) {
555 char header[HEADER_SIZE];
556
557 getconsxy(vc, header + 2);
558 while (p < HEADER_SIZE && this_round > 0) {
559 this_round--;
560 header[p++] = *con_buf0++;
561 }
562 if (!viewed)
563 putconsxy(vc, header + 2);
564 }
565 p -= HEADER_SIZE;
566 col = (p/2) % maxcol;
567 if (this_round > 0) {
568 org0 = org = screen_pos(vc, p/2, viewed);
569 if ((p & 1) && this_round > 0) {
570 char c;
571
572 this_round--;
573 c = *con_buf0++;
574#ifdef __BIG_ENDIAN
575 vcs_scr_writew(vc, c |
576 (vcs_scr_readw(vc, org) & 0xff00), org);
577#else
578 vcs_scr_writew(vc, (c << 8) |
579 (vcs_scr_readw(vc, org) & 0xff), org);
580#endif
581 org++;
582 p++;
583 if (++col == maxcol) {
584 org = screen_pos(vc, p/2, viewed);
585 col = 0;
586 }
587 }
588 p /= 2;
589 p += maxcol - col;
590 }
591 while (this_round > 1) {
592 unsigned short w;
593
594 w = get_unaligned(((unsigned short *)con_buf0));
595 vcs_scr_writew(vc, w, org++);
596 con_buf0 += 2;
597 this_round -= 2;
598 if (++col == maxcol) {
599 org = screen_pos(vc, p, viewed);
600 col = 0;
601 p += maxcol;
602 }
603 }
604 if (this_round > 0) {
605 unsigned char c;
606
607 c = *con_buf0++;
608#ifdef __BIG_ENDIAN
609 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
610#else
611 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
612#endif
613 }
614 }
615 count -= orig_count;
616 written += orig_count;
617 buf += orig_count;
618 pos += orig_count;
619 if (org0)
620 update_region(vc, (unsigned long)(org0), org - org0);
621 }
622 *ppos += written;
623 ret = written;
624 if (written)
625 vcs_scr_updated(vc);
626
627unlock_out:
628 console_unlock();
629 free_page((unsigned long) con_buf);
630 return ret;
631}
632
633static __poll_t
634vcs_poll(struct file *file, poll_table *wait)
635{
636 struct vcs_poll_data *poll = vcs_poll_data_get(file);
637 __poll_t ret = DEFAULT_POLLMASK|EPOLLERR;
638
639 if (poll) {
640 poll_wait(file, &poll->waitq, wait);
641 switch (poll->event) {
642 case VT_UPDATE:
643 ret = DEFAULT_POLLMASK|EPOLLPRI;
644 break;
645 case VT_DEALLOCATE:
646 ret = DEFAULT_POLLMASK|EPOLLHUP|EPOLLERR;
647 break;
648 case 0:
649 ret = DEFAULT_POLLMASK;
650 break;
651 }
652 }
653 return ret;
654}
655
656static int
657vcs_fasync(int fd, struct file *file, int on)
658{
659 struct vcs_poll_data *poll = file->private_data;
660
661 if (!poll) {
662 /* don't allocate anything if all we want is disable fasync */
663 if (!on)
664 return 0;
665 poll = vcs_poll_data_get(file);
666 if (!poll)
667 return -ENOMEM;
668 }
669
670 return fasync_helper(fd, file, on, &poll->fasync);
671}
672
673static int
674vcs_open(struct inode *inode, struct file *filp)
675{
676 unsigned int currcons = console(inode);
677 bool attr = use_attributes(inode);
678 bool uni_mode = use_unicode(inode);
679 int ret = 0;
680
681 /* we currently don't support attributes in unicode mode */
682 if (attr && uni_mode)
683 return -EOPNOTSUPP;
684
685 console_lock();
686 if(currcons && !vc_cons_allocated(currcons-1))
687 ret = -ENXIO;
688 console_unlock();
689 return ret;
690}
691
692static int vcs_release(struct inode *inode, struct file *file)
693{
694 struct vcs_poll_data *poll = file->private_data;
695
696 if (poll)
697 vcs_poll_data_free(poll);
698 return 0;
699}
700
701static const struct file_operations vcs_fops = {
702 .llseek = vcs_lseek,
703 .read = vcs_read,
704 .write = vcs_write,
705 .poll = vcs_poll,
706 .fasync = vcs_fasync,
707 .open = vcs_open,
708 .release = vcs_release,
709};
710
711static struct class *vc_class;
712
713void vcs_make_sysfs(int index)
714{
715 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
716 "vcs%u", index + 1);
717 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 65), NULL,
718 "vcsu%u", index + 1);
719 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
720 "vcsa%u", index + 1);
721}
722
723void vcs_remove_sysfs(int index)
724{
725 device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
726 device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 65));
727 device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
728}
729
730int __init vcs_init(void)
731{
732 unsigned int i;
733
734 if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
735 panic("unable to get major %d for vcs device", VCS_MAJOR);
736 vc_class = class_create(THIS_MODULE, "vc");
737
738 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
739 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 64), NULL, "vcsu");
740 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
741 for (i = 0; i < MIN_NR_CONSOLES; i++)
742 vcs_make_sysfs(i);
743 return 0;
744}
1/*
2 * Provide access to virtual console memory.
3 * /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
4 * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
5 * [minor: N]
6 *
7 * /dev/vcsaN: idem, but including attributes, and prefixed with
8 * the 4 bytes lines,columns,x,y (as screendump used to give).
9 * Attribute/character pair is in native endianity.
10 * [minor: N+128]
11 *
12 * This replaces screendump and part of selection, so that the system
13 * administrator can control access using file system permissions.
14 *
15 * aeb@cwi.nl - efter Friedas begravelse - 950211
16 *
17 * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
18 * - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
19 * - making it shorter - scr_readw are macros which expand in PRETTY long code
20 */
21
22#include <linux/kernel.h>
23#include <linux/major.h>
24#include <linux/errno.h>
25#include <linux/export.h>
26#include <linux/tty.h>
27#include <linux/interrupt.h>
28#include <linux/mm.h>
29#include <linux/init.h>
30#include <linux/vt_kern.h>
31#include <linux/selection.h>
32#include <linux/kbd_kern.h>
33#include <linux/console.h>
34#include <linux/device.h>
35#include <linux/sched.h>
36#include <linux/fs.h>
37#include <linux/poll.h>
38#include <linux/signal.h>
39#include <linux/slab.h>
40#include <linux/notifier.h>
41
42#include <asm/uaccess.h>
43#include <asm/byteorder.h>
44#include <asm/unaligned.h>
45
46#undef attr
47#undef org
48#undef addr
49#define HEADER_SIZE 4
50
51#define CON_BUF_SIZE (CONFIG_BASE_SMALL ? 256 : PAGE_SIZE)
52
53struct vcs_poll_data {
54 struct notifier_block notifier;
55 unsigned int cons_num;
56 bool seen_last_update;
57 wait_queue_head_t waitq;
58 struct fasync_struct *fasync;
59};
60
61static int
62vcs_notifier(struct notifier_block *nb, unsigned long code, void *_param)
63{
64 struct vt_notifier_param *param = _param;
65 struct vc_data *vc = param->vc;
66 struct vcs_poll_data *poll =
67 container_of(nb, struct vcs_poll_data, notifier);
68 int currcons = poll->cons_num;
69
70 if (code != VT_UPDATE)
71 return NOTIFY_DONE;
72
73 if (currcons == 0)
74 currcons = fg_console;
75 else
76 currcons--;
77 if (currcons != vc->vc_num)
78 return NOTIFY_DONE;
79
80 poll->seen_last_update = false;
81 wake_up_interruptible(&poll->waitq);
82 kill_fasync(&poll->fasync, SIGIO, POLL_IN);
83 return NOTIFY_OK;
84}
85
86static void
87vcs_poll_data_free(struct vcs_poll_data *poll)
88{
89 unregister_vt_notifier(&poll->notifier);
90 kfree(poll);
91}
92
93static struct vcs_poll_data *
94vcs_poll_data_get(struct file *file)
95{
96 struct vcs_poll_data *poll = file->private_data;
97
98 if (poll)
99 return poll;
100
101 poll = kzalloc(sizeof(*poll), GFP_KERNEL);
102 if (!poll)
103 return NULL;
104 poll->cons_num = iminor(file->f_path.dentry->d_inode) & 127;
105 init_waitqueue_head(&poll->waitq);
106 poll->notifier.notifier_call = vcs_notifier;
107 if (register_vt_notifier(&poll->notifier) != 0) {
108 kfree(poll);
109 return NULL;
110 }
111
112 /*
113 * This code may be called either through ->poll() or ->fasync().
114 * If we have two threads using the same file descriptor, they could
115 * both enter this function, both notice that the structure hasn't
116 * been allocated yet and go ahead allocating it in parallel, but
117 * only one of them must survive and be shared otherwise we'd leak
118 * memory with a dangling notifier callback.
119 */
120 spin_lock(&file->f_lock);
121 if (!file->private_data) {
122 file->private_data = poll;
123 } else {
124 /* someone else raced ahead of us */
125 vcs_poll_data_free(poll);
126 poll = file->private_data;
127 }
128 spin_unlock(&file->f_lock);
129
130 return poll;
131}
132
133/*
134 * Returns VC for inode.
135 * Must be called with console_lock.
136 */
137static struct vc_data*
138vcs_vc(struct inode *inode, int *viewed)
139{
140 unsigned int currcons = iminor(inode) & 127;
141
142 WARN_CONSOLE_UNLOCKED();
143
144 if (currcons == 0) {
145 currcons = fg_console;
146 if (viewed)
147 *viewed = 1;
148 } else {
149 currcons--;
150 if (viewed)
151 *viewed = 0;
152 }
153 return vc_cons[currcons].d;
154}
155
156/*
157 * Returns size for VC carried by inode.
158 * Must be called with console_lock.
159 */
160static int
161vcs_size(struct inode *inode)
162{
163 int size;
164 int minor = iminor(inode);
165 struct vc_data *vc;
166
167 WARN_CONSOLE_UNLOCKED();
168
169 vc = vcs_vc(inode, NULL);
170 if (!vc)
171 return -ENXIO;
172
173 size = vc->vc_rows * vc->vc_cols;
174
175 if (minor & 128)
176 size = 2*size + HEADER_SIZE;
177 return size;
178}
179
180static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
181{
182 int size;
183
184 console_lock();
185 size = vcs_size(file->f_path.dentry->d_inode);
186 console_unlock();
187 if (size < 0)
188 return size;
189 switch (orig) {
190 default:
191 return -EINVAL;
192 case 2:
193 offset += size;
194 break;
195 case 1:
196 offset += file->f_pos;
197 case 0:
198 break;
199 }
200 if (offset < 0 || offset > size) {
201 return -EINVAL;
202 }
203 file->f_pos = offset;
204 return file->f_pos;
205}
206
207
208static ssize_t
209vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
210{
211 struct inode *inode = file->f_path.dentry->d_inode;
212 unsigned int currcons = iminor(inode);
213 struct vc_data *vc;
214 struct vcs_poll_data *poll;
215 long pos;
216 long attr, read;
217 int col, maxcol, viewed;
218 unsigned short *org = NULL;
219 ssize_t ret;
220 char *con_buf;
221
222 con_buf = (char *) __get_free_page(GFP_KERNEL);
223 if (!con_buf)
224 return -ENOMEM;
225
226 pos = *ppos;
227
228 /* Select the proper current console and verify
229 * sanity of the situation under the console lock.
230 */
231 console_lock();
232
233 attr = (currcons & 128);
234 ret = -ENXIO;
235 vc = vcs_vc(inode, &viewed);
236 if (!vc)
237 goto unlock_out;
238
239 ret = -EINVAL;
240 if (pos < 0)
241 goto unlock_out;
242 poll = file->private_data;
243 if (count && poll)
244 poll->seen_last_update = true;
245 read = 0;
246 ret = 0;
247 while (count) {
248 char *con_buf0, *con_buf_start;
249 long this_round, size;
250 ssize_t orig_count;
251 long p = pos;
252
253 /* Check whether we are above size each round,
254 * as copy_to_user at the end of this loop
255 * could sleep.
256 */
257 size = vcs_size(inode);
258 if (size < 0) {
259 if (read)
260 break;
261 ret = size;
262 goto unlock_out;
263 }
264 if (pos >= size)
265 break;
266 if (count > size - pos)
267 count = size - pos;
268
269 this_round = count;
270 if (this_round > CON_BUF_SIZE)
271 this_round = CON_BUF_SIZE;
272
273 /* Perform the whole read into the local con_buf.
274 * Then we can drop the console spinlock and safely
275 * attempt to move it to userspace.
276 */
277
278 con_buf_start = con_buf0 = con_buf;
279 orig_count = this_round;
280 maxcol = vc->vc_cols;
281 if (!attr) {
282 org = screen_pos(vc, p, viewed);
283 col = p % maxcol;
284 p += maxcol - col;
285 while (this_round-- > 0) {
286 *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
287 if (++col == maxcol) {
288 org = screen_pos(vc, p, viewed);
289 col = 0;
290 p += maxcol;
291 }
292 }
293 } else {
294 if (p < HEADER_SIZE) {
295 size_t tmp_count;
296
297 con_buf0[0] = (char)vc->vc_rows;
298 con_buf0[1] = (char)vc->vc_cols;
299 getconsxy(vc, con_buf0 + 2);
300
301 con_buf_start += p;
302 this_round += p;
303 if (this_round > CON_BUF_SIZE) {
304 this_round = CON_BUF_SIZE;
305 orig_count = this_round - p;
306 }
307
308 tmp_count = HEADER_SIZE;
309 if (tmp_count > this_round)
310 tmp_count = this_round;
311
312 /* Advance state pointers and move on. */
313 this_round -= tmp_count;
314 p = HEADER_SIZE;
315 con_buf0 = con_buf + HEADER_SIZE;
316 /* If this_round >= 0, then p is even... */
317 } else if (p & 1) {
318 /* Skip first byte for output if start address is odd
319 * Update region sizes up/down depending on free
320 * space in buffer.
321 */
322 con_buf_start++;
323 if (this_round < CON_BUF_SIZE)
324 this_round++;
325 else
326 orig_count--;
327 }
328 if (this_round > 0) {
329 unsigned short *tmp_buf = (unsigned short *)con_buf0;
330
331 p -= HEADER_SIZE;
332 p /= 2;
333 col = p % maxcol;
334
335 org = screen_pos(vc, p, viewed);
336 p += maxcol - col;
337
338 /* Buffer has even length, so we can always copy
339 * character + attribute. We do not copy last byte
340 * to userspace if this_round is odd.
341 */
342 this_round = (this_round + 1) >> 1;
343
344 while (this_round) {
345 *tmp_buf++ = vcs_scr_readw(vc, org++);
346 this_round --;
347 if (++col == maxcol) {
348 org = screen_pos(vc, p, viewed);
349 col = 0;
350 p += maxcol;
351 }
352 }
353 }
354 }
355
356 /* Finally, release the console semaphore while we push
357 * all the data to userspace from our temporary buffer.
358 *
359 * AKPM: Even though it's a semaphore, we should drop it because
360 * the pagefault handling code may want to call printk().
361 */
362
363 console_unlock();
364 ret = copy_to_user(buf, con_buf_start, orig_count);
365 console_lock();
366
367 if (ret) {
368 read += (orig_count - ret);
369 ret = -EFAULT;
370 break;
371 }
372 buf += orig_count;
373 pos += orig_count;
374 read += orig_count;
375 count -= orig_count;
376 }
377 *ppos += read;
378 if (read)
379 ret = read;
380unlock_out:
381 console_unlock();
382 free_page((unsigned long) con_buf);
383 return ret;
384}
385
386static ssize_t
387vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
388{
389 struct inode *inode = file->f_path.dentry->d_inode;
390 unsigned int currcons = iminor(inode);
391 struct vc_data *vc;
392 long pos;
393 long attr, size, written;
394 char *con_buf0;
395 int col, maxcol, viewed;
396 u16 *org0 = NULL, *org = NULL;
397 size_t ret;
398 char *con_buf;
399
400 con_buf = (char *) __get_free_page(GFP_KERNEL);
401 if (!con_buf)
402 return -ENOMEM;
403
404 pos = *ppos;
405
406 /* Select the proper current console and verify
407 * sanity of the situation under the console lock.
408 */
409 console_lock();
410
411 attr = (currcons & 128);
412 ret = -ENXIO;
413 vc = vcs_vc(inode, &viewed);
414 if (!vc)
415 goto unlock_out;
416
417 size = vcs_size(inode);
418 ret = -EINVAL;
419 if (pos < 0 || pos > size)
420 goto unlock_out;
421 if (count > size - pos)
422 count = size - pos;
423 written = 0;
424 while (count) {
425 long this_round = count;
426 size_t orig_count;
427 long p;
428
429 if (this_round > CON_BUF_SIZE)
430 this_round = CON_BUF_SIZE;
431
432 /* Temporarily drop the console lock so that we can read
433 * in the write data from userspace safely.
434 */
435 console_unlock();
436 ret = copy_from_user(con_buf, buf, this_round);
437 console_lock();
438
439 if (ret) {
440 this_round -= ret;
441 if (!this_round) {
442 /* Abort loop if no data were copied. Otherwise
443 * fail with -EFAULT.
444 */
445 if (written)
446 break;
447 ret = -EFAULT;
448 goto unlock_out;
449 }
450 }
451
452 /* The vcs_size might have changed while we slept to grab
453 * the user buffer, so recheck.
454 * Return data written up to now on failure.
455 */
456 size = vcs_size(inode);
457 if (size < 0) {
458 if (written)
459 break;
460 ret = size;
461 goto unlock_out;
462 }
463 if (pos >= size)
464 break;
465 if (this_round > size - pos)
466 this_round = size - pos;
467
468 /* OK, now actually push the write to the console
469 * under the lock using the local kernel buffer.
470 */
471
472 con_buf0 = con_buf;
473 orig_count = this_round;
474 maxcol = vc->vc_cols;
475 p = pos;
476 if (!attr) {
477 org0 = org = screen_pos(vc, p, viewed);
478 col = p % maxcol;
479 p += maxcol - col;
480
481 while (this_round > 0) {
482 unsigned char c = *con_buf0++;
483
484 this_round--;
485 vcs_scr_writew(vc,
486 (vcs_scr_readw(vc, org) & 0xff00) | c, org);
487 org++;
488 if (++col == maxcol) {
489 org = screen_pos(vc, p, viewed);
490 col = 0;
491 p += maxcol;
492 }
493 }
494 } else {
495 if (p < HEADER_SIZE) {
496 char header[HEADER_SIZE];
497
498 getconsxy(vc, header + 2);
499 while (p < HEADER_SIZE && this_round > 0) {
500 this_round--;
501 header[p++] = *con_buf0++;
502 }
503 if (!viewed)
504 putconsxy(vc, header + 2);
505 }
506 p -= HEADER_SIZE;
507 col = (p/2) % maxcol;
508 if (this_round > 0) {
509 org0 = org = screen_pos(vc, p/2, viewed);
510 if ((p & 1) && this_round > 0) {
511 char c;
512
513 this_round--;
514 c = *con_buf0++;
515#ifdef __BIG_ENDIAN
516 vcs_scr_writew(vc, c |
517 (vcs_scr_readw(vc, org) & 0xff00), org);
518#else
519 vcs_scr_writew(vc, (c << 8) |
520 (vcs_scr_readw(vc, org) & 0xff), org);
521#endif
522 org++;
523 p++;
524 if (++col == maxcol) {
525 org = screen_pos(vc, p/2, viewed);
526 col = 0;
527 }
528 }
529 p /= 2;
530 p += maxcol - col;
531 }
532 while (this_round > 1) {
533 unsigned short w;
534
535 w = get_unaligned(((unsigned short *)con_buf0));
536 vcs_scr_writew(vc, w, org++);
537 con_buf0 += 2;
538 this_round -= 2;
539 if (++col == maxcol) {
540 org = screen_pos(vc, p, viewed);
541 col = 0;
542 p += maxcol;
543 }
544 }
545 if (this_round > 0) {
546 unsigned char c;
547
548 c = *con_buf0++;
549#ifdef __BIG_ENDIAN
550 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
551#else
552 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
553#endif
554 }
555 }
556 count -= orig_count;
557 written += orig_count;
558 buf += orig_count;
559 pos += orig_count;
560 if (org0)
561 update_region(vc, (unsigned long)(org0), org - org0);
562 }
563 *ppos += written;
564 ret = written;
565 if (written)
566 vcs_scr_updated(vc);
567
568unlock_out:
569 console_unlock();
570 free_page((unsigned long) con_buf);
571 return ret;
572}
573
574static unsigned int
575vcs_poll(struct file *file, poll_table *wait)
576{
577 struct vcs_poll_data *poll = vcs_poll_data_get(file);
578 int ret = DEFAULT_POLLMASK|POLLERR|POLLPRI;
579
580 if (poll) {
581 poll_wait(file, &poll->waitq, wait);
582 if (poll->seen_last_update)
583 ret = DEFAULT_POLLMASK;
584 }
585 return ret;
586}
587
588static int
589vcs_fasync(int fd, struct file *file, int on)
590{
591 struct vcs_poll_data *poll = file->private_data;
592
593 if (!poll) {
594 /* don't allocate anything if all we want is disable fasync */
595 if (!on)
596 return 0;
597 poll = vcs_poll_data_get(file);
598 if (!poll)
599 return -ENOMEM;
600 }
601
602 return fasync_helper(fd, file, on, &poll->fasync);
603}
604
605static int
606vcs_open(struct inode *inode, struct file *filp)
607{
608 unsigned int currcons = iminor(inode) & 127;
609 int ret = 0;
610
611 console_lock();
612 if(currcons && !vc_cons_allocated(currcons-1))
613 ret = -ENXIO;
614 console_unlock();
615 return ret;
616}
617
618static int vcs_release(struct inode *inode, struct file *file)
619{
620 struct vcs_poll_data *poll = file->private_data;
621
622 if (poll)
623 vcs_poll_data_free(poll);
624 return 0;
625}
626
627static const struct file_operations vcs_fops = {
628 .llseek = vcs_lseek,
629 .read = vcs_read,
630 .write = vcs_write,
631 .poll = vcs_poll,
632 .fasync = vcs_fasync,
633 .open = vcs_open,
634 .release = vcs_release,
635};
636
637static struct class *vc_class;
638
639void vcs_make_sysfs(int index)
640{
641 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
642 "vcs%u", index + 1);
643 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
644 "vcsa%u", index + 1);
645}
646
647void vcs_remove_sysfs(int index)
648{
649 device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
650 device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
651}
652
653int __init vcs_init(void)
654{
655 unsigned int i;
656
657 if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
658 panic("unable to get major %d for vcs device", VCS_MAJOR);
659 vc_class = class_create(THIS_MODULE, "vc");
660
661 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
662 device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
663 for (i = 0; i < MIN_NR_CONSOLES; i++)
664 vcs_make_sysfs(i);
665 return 0;
666}