vt: Add virtual console keyboard mode OFF
[linux-2.6.git] / drivers / tty / vt / vc_screen.c
1 /*
2  * linux/drivers/char/vc_screen.c
3  *
4  * Provide access to virtual console memory.
5  * /dev/vcs0: the screen as it is being viewed right now (possibly scrolled)
6  * /dev/vcsN: the screen of /dev/ttyN (1 <= N <= 63)
7  *            [minor: N]
8  *
9  * /dev/vcsaN: idem, but including attributes, and prefixed with
10  *      the 4 bytes lines,columns,x,y (as screendump used to give).
11  *      Attribute/character pair is in native endianity.
12  *            [minor: N+128]
13  *
14  * This replaces screendump and part of selection, so that the system
15  * administrator can control access using file system permissions.
16  *
17  * aeb@cwi.nl - efter Friedas begravelse - 950211
18  *
19  * machek@k332.feld.cvut.cz - modified not to send characters to wrong console
20  *       - fixed some fatal off-by-one bugs (0-- no longer == -1 -> looping and looping and looping...)
21  *       - making it shorter - scr_readw are macros which expand in PRETTY long code
22  */
23
24 #include <linux/kernel.h>
25 #include <linux/major.h>
26 #include <linux/errno.h>
27 #include <linux/tty.h>
28 #include <linux/interrupt.h>
29 #include <linux/mm.h>
30 #include <linux/init.h>
31 #include <linux/mutex.h>
32 #include <linux/vt_kern.h>
33 #include <linux/selection.h>
34 #include <linux/kbd_kern.h>
35 #include <linux/console.h>
36 #include <linux/device.h>
37 #include <linux/smp_lock.h>
38 #include <linux/sched.h>
39 #include <linux/fs.h>
40 #include <linux/poll.h>
41 #include <linux/signal.h>
42 #include <linux/slab.h>
43 #include <linux/notifier.h>
44
45 #include <asm/uaccess.h>
46 #include <asm/byteorder.h>
47 #include <asm/unaligned.h>
48
49 #undef attr
50 #undef org
51 #undef addr
52 #define HEADER_SIZE     4
53
54 struct 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
62 static int
63 vcs_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
87 static void
88 vcs_poll_data_free(struct vcs_poll_data *poll)
89 {
90         unregister_vt_notifier(&poll->notifier);
91         kfree(poll);
92 }
93
94 static struct vcs_poll_data *
95 vcs_poll_data_get(struct file *file)
96 {
97         struct vcs_poll_data *poll = file->private_data;
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->f_path.dentry->d_inode) & 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                 vcs_poll_data_free(poll);
127                 poll = file->private_data;
128         }
129         spin_unlock(&file->f_lock);
130
131         return poll;
132 }
133
134 static int
135 vcs_size(struct inode *inode)
136 {
137         int size;
138         int minor = iminor(inode);
139         int currcons = minor & 127;
140         struct vc_data *vc;
141
142         if (currcons == 0)
143                 currcons = fg_console;
144         else
145                 currcons--;
146         if (!vc_cons_allocated(currcons))
147                 return -ENXIO;
148         vc = vc_cons[currcons].d;
149
150         size = vc->vc_rows * vc->vc_cols;
151
152         if (minor & 128)
153                 size = 2*size + HEADER_SIZE;
154         return size;
155 }
156
157 static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
158 {
159         int size;
160
161         mutex_lock(&con_buf_mtx);
162         size = vcs_size(file->f_path.dentry->d_inode);
163         switch (orig) {
164                 default:
165                         mutex_unlock(&con_buf_mtx);
166                         return -EINVAL;
167                 case 2:
168                         offset += size;
169                         break;
170                 case 1:
171                         offset += file->f_pos;
172                 case 0:
173                         break;
174         }
175         if (offset < 0 || offset > size) {
176                 mutex_unlock(&con_buf_mtx);
177                 return -EINVAL;
178         }
179         file->f_pos = offset;
180         mutex_unlock(&con_buf_mtx);
181         return file->f_pos;
182 }
183
184
185 static ssize_t
186 vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
187 {
188         struct inode *inode = file->f_path.dentry->d_inode;
189         unsigned int currcons = iminor(inode);
190         struct vc_data *vc;
191         struct vcs_poll_data *poll;
192         long pos;
193         long viewed, attr, read;
194         int col, maxcol;
195         unsigned short *org = NULL;
196         ssize_t ret;
197
198         mutex_lock(&con_buf_mtx);
199
200         pos = *ppos;
201
202         /* Select the proper current console and verify
203          * sanity of the situation under the console lock.
204          */
205         console_lock();
206
207         attr = (currcons & 128);
208         currcons = (currcons & 127);
209         if (currcons == 0) {
210                 currcons = fg_console;
211                 viewed = 1;
212         } else {
213                 currcons--;
214                 viewed = 0;
215         }
216         ret = -ENXIO;
217         if (!vc_cons_allocated(currcons))
218                 goto unlock_out;
219         vc = vc_cons[currcons].d;
220
221         ret = -EINVAL;
222         if (pos < 0)
223                 goto unlock_out;
224         poll = file->private_data;
225         if (count && poll)
226                 poll->seen_last_update = true;
227         read = 0;
228         ret = 0;
229         while (count) {
230                 char *con_buf0, *con_buf_start;
231                 long this_round, size;
232                 ssize_t orig_count;
233                 long p = pos;
234
235                 /* Check whether we are above size each round,
236                  * as copy_to_user at the end of this loop
237                  * could sleep.
238                  */
239                 size = vcs_size(inode);
240                 if (pos >= size)
241                         break;
242                 if (count > size - pos)
243                         count = size - pos;
244
245                 this_round = count;
246                 if (this_round > CON_BUF_SIZE)
247                         this_round = CON_BUF_SIZE;
248
249                 /* Perform the whole read into the local con_buf.
250                  * Then we can drop the console spinlock and safely
251                  * attempt to move it to userspace.
252                  */
253
254                 con_buf_start = con_buf0 = con_buf;
255                 orig_count = this_round;
256                 maxcol = vc->vc_cols;
257                 if (!attr) {
258                         org = screen_pos(vc, p, viewed);
259                         col = p % maxcol;
260                         p += maxcol - col;
261                         while (this_round-- > 0) {
262                                 *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
263                                 if (++col == maxcol) {
264                                         org = screen_pos(vc, p, viewed);
265                                         col = 0;
266                                         p += maxcol;
267                                 }
268                         }
269                 } else {
270                         if (p < HEADER_SIZE) {
271                                 size_t tmp_count;
272
273                                 con_buf0[0] = (char)vc->vc_rows;
274                                 con_buf0[1] = (char)vc->vc_cols;
275                                 getconsxy(vc, con_buf0 + 2);
276
277                                 con_buf_start += p;
278                                 this_round += p;
279                                 if (this_round > CON_BUF_SIZE) {
280                                         this_round = CON_BUF_SIZE;
281                                         orig_count = this_round - p;
282                                 }
283
284                                 tmp_count = HEADER_SIZE;
285                                 if (tmp_count > this_round)
286                                         tmp_count = this_round;
287
288                                 /* Advance state pointers and move on. */
289                                 this_round -= tmp_count;
290                                 p = HEADER_SIZE;
291                                 con_buf0 = con_buf + HEADER_SIZE;
292                                 /* If this_round >= 0, then p is even... */
293                         } else if (p & 1) {
294                                 /* Skip first byte for output if start address is odd
295                                  * Update region sizes up/down depending on free
296                                  * space in buffer.
297                                  */
298                                 con_buf_start++;
299                                 if (this_round < CON_BUF_SIZE)
300                                         this_round++;
301                                 else
302                                         orig_count--;
303                         }
304                         if (this_round > 0) {
305                                 unsigned short *tmp_buf = (unsigned short *)con_buf0;
306
307                                 p -= HEADER_SIZE;
308                                 p /= 2;
309                                 col = p % maxcol;
310
311                                 org = screen_pos(vc, p, viewed);
312                                 p += maxcol - col;
313
314                                 /* Buffer has even length, so we can always copy
315                                  * character + attribute. We do not copy last byte
316                                  * to userspace if this_round is odd.
317                                  */
318                                 this_round = (this_round + 1) >> 1;
319
320                                 while (this_round) {
321                                         *tmp_buf++ = vcs_scr_readw(vc, org++);
322                                         this_round --;
323                                         if (++col == maxcol) {
324                                                 org = screen_pos(vc, p, viewed);
325                                                 col = 0;
326                                                 p += maxcol;
327                                         }
328                                 }
329                         }
330                 }
331
332                 /* Finally, release the console semaphore while we push
333                  * all the data to userspace from our temporary buffer.
334                  *
335                  * AKPM: Even though it's a semaphore, we should drop it because
336                  * the pagefault handling code may want to call printk().
337                  */
338
339                 console_unlock();
340                 ret = copy_to_user(buf, con_buf_start, orig_count);
341                 console_lock();
342
343                 if (ret) {
344                         read += (orig_count - ret);
345                         ret = -EFAULT;
346                         break;
347                 }
348                 buf += orig_count;
349                 pos += orig_count;
350                 read += orig_count;
351                 count -= orig_count;
352         }
353         *ppos += read;
354         if (read)
355                 ret = read;
356 unlock_out:
357         console_unlock();
358         mutex_unlock(&con_buf_mtx);
359         return ret;
360 }
361
362 static ssize_t
363 vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
364 {
365         struct inode *inode = file->f_path.dentry->d_inode;
366         unsigned int currcons = iminor(inode);
367         struct vc_data *vc;
368         long pos;
369         long viewed, attr, size, written;
370         char *con_buf0;
371         int col, maxcol;
372         u16 *org0 = NULL, *org = NULL;
373         size_t ret;
374
375         mutex_lock(&con_buf_mtx);
376
377         pos = *ppos;
378
379         /* Select the proper current console and verify
380          * sanity of the situation under the console lock.
381          */
382         console_lock();
383
384         attr = (currcons & 128);
385         currcons = (currcons & 127);
386
387         if (currcons == 0) {
388                 currcons = fg_console;
389                 viewed = 1;
390         } else {
391                 currcons--;
392                 viewed = 0;
393         }
394         ret = -ENXIO;
395         if (!vc_cons_allocated(currcons))
396                 goto unlock_out;
397         vc = vc_cons[currcons].d;
398
399         size = vcs_size(inode);
400         ret = -EINVAL;
401         if (pos < 0 || pos > size)
402                 goto unlock_out;
403         if (count > size - pos)
404                 count = size - pos;
405         written = 0;
406         while (count) {
407                 long this_round = count;
408                 size_t orig_count;
409                 long p;
410
411                 if (this_round > CON_BUF_SIZE)
412                         this_round = CON_BUF_SIZE;
413
414                 /* Temporarily drop the console lock so that we can read
415                  * in the write data from userspace safely.
416                  */
417                 console_unlock();
418                 ret = copy_from_user(con_buf, buf, this_round);
419                 console_lock();
420
421                 if (ret) {
422                         this_round -= ret;
423                         if (!this_round) {
424                                 /* Abort loop if no data were copied. Otherwise
425                                  * fail with -EFAULT.
426                                  */
427                                 if (written)
428                                         break;
429                                 ret = -EFAULT;
430                                 goto unlock_out;
431                         }
432                 }
433
434                 /* The vcs_size might have changed while we slept to grab
435                  * the user buffer, so recheck.
436                  * Return data written up to now on failure.
437                  */
438                 size = vcs_size(inode);
439                 if (pos >= size)
440                         break;
441                 if (this_round > size - pos)
442                         this_round = size - pos;
443
444                 /* OK, now actually push the write to the console
445                  * under the lock using the local kernel buffer.
446                  */
447
448                 con_buf0 = con_buf;
449                 orig_count = this_round;
450                 maxcol = vc->vc_cols;
451                 p = pos;
452                 if (!attr) {
453                         org0 = org = screen_pos(vc, p, viewed);
454                         col = p % maxcol;
455                         p += maxcol - col;
456
457                         while (this_round > 0) {
458                                 unsigned char c = *con_buf0++;
459
460                                 this_round--;
461                                 vcs_scr_writew(vc,
462                                                (vcs_scr_readw(vc, org) & 0xff00) | c, org);
463                                 org++;
464                                 if (++col == maxcol) {
465                                         org = screen_pos(vc, p, viewed);
466                                         col = 0;
467                                         p += maxcol;
468                                 }
469                         }
470                 } else {
471                         if (p < HEADER_SIZE) {
472                                 char header[HEADER_SIZE];
473
474                                 getconsxy(vc, header + 2);
475                                 while (p < HEADER_SIZE && this_round > 0) {
476                                         this_round--;
477                                         header[p++] = *con_buf0++;
478                                 }
479                                 if (!viewed)
480                                         putconsxy(vc, header + 2);
481                         }
482                         p -= HEADER_SIZE;
483                         col = (p/2) % maxcol;
484                         if (this_round > 0) {
485                                 org0 = org = screen_pos(vc, p/2, viewed);
486                                 if ((p & 1) && this_round > 0) {
487                                         char c;
488
489                                         this_round--;
490                                         c = *con_buf0++;
491 #ifdef __BIG_ENDIAN
492                                         vcs_scr_writew(vc, c |
493                                              (vcs_scr_readw(vc, org) & 0xff00), org);
494 #else
495                                         vcs_scr_writew(vc, (c << 8) |
496                                              (vcs_scr_readw(vc, org) & 0xff), org);
497 #endif
498                                         org++;
499                                         p++;
500                                         if (++col == maxcol) {
501                                                 org = screen_pos(vc, p/2, viewed);
502                                                 col = 0;
503                                         }
504                                 }
505                                 p /= 2;
506                                 p += maxcol - col;
507                         }
508                         while (this_round > 1) {
509                                 unsigned short w;
510
511                                 w = get_unaligned(((unsigned short *)con_buf0));
512                                 vcs_scr_writew(vc, w, org++);
513                                 con_buf0 += 2;
514                                 this_round -= 2;
515                                 if (++col == maxcol) {
516                                         org = screen_pos(vc, p, viewed);
517                                         col = 0;
518                                         p += maxcol;
519                                 }
520                         }
521                         if (this_round > 0) {
522                                 unsigned char c;
523
524                                 c = *con_buf0++;
525 #ifdef __BIG_ENDIAN
526                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
527 #else
528                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
529 #endif
530                         }
531                 }
532                 count -= orig_count;
533                 written += orig_count;
534                 buf += orig_count;
535                 pos += orig_count;
536                 if (org0)
537                         update_region(vc, (unsigned long)(org0), org - org0);
538         }
539         *ppos += written;
540         ret = written;
541         if (written)
542                 vcs_scr_updated(vc);
543
544 unlock_out:
545         console_unlock();
546
547         mutex_unlock(&con_buf_mtx);
548
549         return ret;
550 }
551
552 static unsigned int
553 vcs_poll(struct file *file, poll_table *wait)
554 {
555         struct vcs_poll_data *poll = vcs_poll_data_get(file);
556         int ret = DEFAULT_POLLMASK|POLLERR|POLLPRI;
557
558         if (poll) {
559                 poll_wait(file, &poll->waitq, wait);
560                 if (poll->seen_last_update)
561                         ret = DEFAULT_POLLMASK;
562         }
563         return ret;
564 }
565
566 static int
567 vcs_fasync(int fd, struct file *file, int on)
568 {
569         struct vcs_poll_data *poll = file->private_data;
570
571         if (!poll) {
572                 /* don't allocate anything if all we want is disable fasync */
573                 if (!on)
574                         return 0;
575                 poll = vcs_poll_data_get(file);
576                 if (!poll)
577                         return -ENOMEM;
578         }
579
580         return fasync_helper(fd, file, on, &poll->fasync);
581 }
582
583 static int
584 vcs_open(struct inode *inode, struct file *filp)
585 {
586         unsigned int currcons = iminor(inode) & 127;
587         int ret = 0;
588         
589         tty_lock();
590         if(currcons && !vc_cons_allocated(currcons-1))
591                 ret = -ENXIO;
592         tty_unlock();
593         return ret;
594 }
595
596 static int vcs_release(struct inode *inode, struct file *file)
597 {
598         struct vcs_poll_data *poll = file->private_data;
599
600         if (poll)
601                 vcs_poll_data_free(poll);
602         return 0;
603 }
604
605 static const struct file_operations vcs_fops = {
606         .llseek         = vcs_lseek,
607         .read           = vcs_read,
608         .write          = vcs_write,
609         .poll           = vcs_poll,
610         .fasync         = vcs_fasync,
611         .open           = vcs_open,
612         .release        = vcs_release,
613 };
614
615 static struct class *vc_class;
616
617 void vcs_make_sysfs(int index)
618 {
619         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 1), NULL,
620                       "vcs%u", index + 1);
621         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, index + 129), NULL,
622                       "vcsa%u", index + 1);
623 }
624
625 void vcs_remove_sysfs(int index)
626 {
627         device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 1));
628         device_destroy(vc_class, MKDEV(VCS_MAJOR, index + 129));
629 }
630
631 int __init vcs_init(void)
632 {
633         unsigned int i;
634
635         if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
636                 panic("unable to get major %d for vcs device", VCS_MAJOR);
637         vc_class = class_create(THIS_MODULE, "vc");
638
639         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs");
640         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa");
641         for (i = 0; i < MIN_NR_CONSOLES; i++)
642                 vcs_make_sysfs(i);
643         return 0;
644 }