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