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