Driver core: convert vc code to use struct device
[linux-2.6.git] / drivers / char / 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/sched.h>
29 #include <linux/interrupt.h>
30 #include <linux/mm.h>
31 #include <linux/init.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/smp_lock.h>
37 #include <linux/device.h>
38 #include <asm/uaccess.h>
39 #include <asm/byteorder.h>
40 #include <asm/unaligned.h>
41
42 #undef attr
43 #undef org
44 #undef addr
45 #define HEADER_SIZE     4
46
47 static int
48 vcs_size(struct inode *inode)
49 {
50         int size;
51         int minor = iminor(inode);
52         int currcons = minor & 127;
53         struct vc_data *vc;
54
55         if (currcons == 0)
56                 currcons = fg_console;
57         else
58                 currcons--;
59         if (!vc_cons_allocated(currcons))
60                 return -ENXIO;
61         vc = vc_cons[currcons].d;
62
63         size = vc->vc_rows * vc->vc_cols;
64
65         if (minor & 128)
66                 size = 2*size + HEADER_SIZE;
67         return size;
68 }
69
70 static loff_t vcs_lseek(struct file *file, loff_t offset, int orig)
71 {
72         int size;
73
74         down(&con_buf_sem);
75         size = vcs_size(file->f_dentry->d_inode);
76         switch (orig) {
77                 default:
78                         up(&con_buf_sem);
79                         return -EINVAL;
80                 case 2:
81                         offset += size;
82                         break;
83                 case 1:
84                         offset += file->f_pos;
85                 case 0:
86                         break;
87         }
88         if (offset < 0 || offset > size) {
89                 up(&con_buf_sem);
90                 return -EINVAL;
91         }
92         file->f_pos = offset;
93         up(&con_buf_sem);
94         return file->f_pos;
95 }
96
97
98 static ssize_t
99 vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
100 {
101         struct inode *inode = file->f_dentry->d_inode;
102         unsigned int currcons = iminor(inode);
103         struct vc_data *vc;
104         long pos;
105         long viewed, attr, read;
106         int col, maxcol;
107         unsigned short *org = NULL;
108         ssize_t ret;
109
110         down(&con_buf_sem);
111
112         pos = *ppos;
113
114         /* Select the proper current console and verify
115          * sanity of the situation under the console lock.
116          */
117         acquire_console_sem();
118
119         attr = (currcons & 128);
120         currcons = (currcons & 127);
121         if (currcons == 0) {
122                 currcons = fg_console;
123                 viewed = 1;
124         } else {
125                 currcons--;
126                 viewed = 0;
127         }
128         ret = -ENXIO;
129         if (!vc_cons_allocated(currcons))
130                 goto unlock_out;
131         vc = vc_cons[currcons].d;
132
133         ret = -EINVAL;
134         if (pos < 0)
135                 goto unlock_out;
136         read = 0;
137         ret = 0;
138         while (count) {
139                 char *con_buf0, *con_buf_start;
140                 long this_round, size;
141                 ssize_t orig_count;
142                 long p = pos;
143
144                 /* Check whether we are above size each round,
145                  * as copy_to_user at the end of this loop
146                  * could sleep.
147                  */
148                 size = vcs_size(inode);
149                 if (pos >= size)
150                         break;
151                 if (count > size - pos)
152                         count = size - pos;
153
154                 this_round = count;
155                 if (this_round > CON_BUF_SIZE)
156                         this_round = CON_BUF_SIZE;
157
158                 /* Perform the whole read into the local con_buf.
159                  * Then we can drop the console spinlock and safely
160                  * attempt to move it to userspace.
161                  */
162
163                 con_buf_start = con_buf0 = con_buf;
164                 orig_count = this_round;
165                 maxcol = vc->vc_cols;
166                 if (!attr) {
167                         org = screen_pos(vc, p, viewed);
168                         col = p % maxcol;
169                         p += maxcol - col;
170                         while (this_round-- > 0) {
171                                 *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff);
172                                 if (++col == maxcol) {
173                                         org = screen_pos(vc, p, viewed);
174                                         col = 0;
175                                         p += maxcol;
176                                 }
177                         }
178                 } else {
179                         if (p < HEADER_SIZE) {
180                                 size_t tmp_count;
181
182                                 con_buf0[0] = (char)vc->vc_rows;
183                                 con_buf0[1] = (char)vc->vc_cols;
184                                 getconsxy(vc, con_buf0 + 2);
185
186                                 con_buf_start += p;
187                                 this_round += p;
188                                 if (this_round > CON_BUF_SIZE) {
189                                         this_round = CON_BUF_SIZE;
190                                         orig_count = this_round - p;
191                                 }
192
193                                 tmp_count = HEADER_SIZE;
194                                 if (tmp_count > this_round)
195                                         tmp_count = this_round;
196
197                                 /* Advance state pointers and move on. */
198                                 this_round -= tmp_count;
199                                 p = HEADER_SIZE;
200                                 con_buf0 = con_buf + HEADER_SIZE;
201                                 /* If this_round >= 0, then p is even... */
202                         } else if (p & 1) {
203                                 /* Skip first byte for output if start address is odd
204                                  * Update region sizes up/down depending on free
205                                  * space in buffer.
206                                  */
207                                 con_buf_start++;
208                                 if (this_round < CON_BUF_SIZE)
209                                         this_round++;
210                                 else
211                                         orig_count--;
212                         }
213                         if (this_round > 0) {
214                                 unsigned short *tmp_buf = (unsigned short *)con_buf0;
215
216                                 p -= HEADER_SIZE;
217                                 p /= 2;
218                                 col = p % maxcol;
219
220                                 org = screen_pos(vc, p, viewed);
221                                 p += maxcol - col;
222
223                                 /* Buffer has even length, so we can always copy
224                                  * character + attribute. We do not copy last byte
225                                  * to userspace if this_round is odd.
226                                  */
227                                 this_round = (this_round + 1) >> 1;
228
229                                 while (this_round) {
230                                         *tmp_buf++ = vcs_scr_readw(vc, org++);
231                                         this_round --;
232                                         if (++col == maxcol) {
233                                                 org = screen_pos(vc, p, viewed);
234                                                 col = 0;
235                                                 p += maxcol;
236                                         }
237                                 }
238                         }
239                 }
240
241                 /* Finally, release the console semaphore while we push
242                  * all the data to userspace from our temporary buffer.
243                  *
244                  * AKPM: Even though it's a semaphore, we should drop it because
245                  * the pagefault handling code may want to call printk().
246                  */
247
248                 release_console_sem();
249                 ret = copy_to_user(buf, con_buf_start, orig_count);
250                 acquire_console_sem();
251
252                 if (ret) {
253                         read += (orig_count - ret);
254                         ret = -EFAULT;
255                         break;
256                 }
257                 buf += orig_count;
258                 pos += orig_count;
259                 read += orig_count;
260                 count -= orig_count;
261         }
262         *ppos += read;
263         if (read)
264                 ret = read;
265 unlock_out:
266         release_console_sem();
267         up(&con_buf_sem);
268         return ret;
269 }
270
271 static ssize_t
272 vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
273 {
274         struct inode *inode = file->f_dentry->d_inode;
275         unsigned int currcons = iminor(inode);
276         struct vc_data *vc;
277         long pos;
278         long viewed, attr, size, written;
279         char *con_buf0;
280         int col, maxcol;
281         u16 *org0 = NULL, *org = NULL;
282         size_t ret;
283
284         down(&con_buf_sem);
285
286         pos = *ppos;
287
288         /* Select the proper current console and verify
289          * sanity of the situation under the console lock.
290          */
291         acquire_console_sem();
292
293         attr = (currcons & 128);
294         currcons = (currcons & 127);
295
296         if (currcons == 0) {
297                 currcons = fg_console;
298                 viewed = 1;
299         } else {
300                 currcons--;
301                 viewed = 0;
302         }
303         ret = -ENXIO;
304         if (!vc_cons_allocated(currcons))
305                 goto unlock_out;
306         vc = vc_cons[currcons].d;
307
308         size = vcs_size(inode);
309         ret = -EINVAL;
310         if (pos < 0 || pos > size)
311                 goto unlock_out;
312         if (count > size - pos)
313                 count = size - pos;
314         written = 0;
315         while (count) {
316                 long this_round = count;
317                 size_t orig_count;
318                 long p;
319
320                 if (this_round > CON_BUF_SIZE)
321                         this_round = CON_BUF_SIZE;
322
323                 /* Temporarily drop the console lock so that we can read
324                  * in the write data from userspace safely.
325                  */
326                 release_console_sem();
327                 ret = copy_from_user(con_buf, buf, this_round);
328                 acquire_console_sem();
329
330                 if (ret) {
331                         this_round -= ret;
332                         if (!this_round) {
333                                 /* Abort loop if no data were copied. Otherwise
334                                  * fail with -EFAULT.
335                                  */
336                                 if (written)
337                                         break;
338                                 ret = -EFAULT;
339                                 goto unlock_out;
340                         }
341                 }
342
343                 /* The vcs_size might have changed while we slept to grab
344                  * the user buffer, so recheck.
345                  * Return data written up to now on failure.
346                  */
347                 size = vcs_size(inode);
348                 if (pos >= size)
349                         break;
350                 if (this_round > size - pos)
351                         this_round = size - pos;
352
353                 /* OK, now actually push the write to the console
354                  * under the lock using the local kernel buffer.
355                  */
356
357                 con_buf0 = con_buf;
358                 orig_count = this_round;
359                 maxcol = vc->vc_cols;
360                 p = pos;
361                 if (!attr) {
362                         org0 = org = screen_pos(vc, p, viewed);
363                         col = p % maxcol;
364                         p += maxcol - col;
365
366                         while (this_round > 0) {
367                                 unsigned char c = *con_buf0++;
368
369                                 this_round--;
370                                 vcs_scr_writew(vc,
371                                                (vcs_scr_readw(vc, org) & 0xff00) | c, org);
372                                 org++;
373                                 if (++col == maxcol) {
374                                         org = screen_pos(vc, p, viewed);
375                                         col = 0;
376                                         p += maxcol;
377                                 }
378                         }
379                 } else {
380                         if (p < HEADER_SIZE) {
381                                 char header[HEADER_SIZE];
382
383                                 getconsxy(vc, header + 2);
384                                 while (p < HEADER_SIZE && this_round > 0) {
385                                         this_round--;
386                                         header[p++] = *con_buf0++;
387                                 }
388                                 if (!viewed)
389                                         putconsxy(vc, header + 2);
390                         }
391                         p -= HEADER_SIZE;
392                         col = (p/2) % maxcol;
393                         if (this_round > 0) {
394                                 org0 = org = screen_pos(vc, p/2, viewed);
395                                 if ((p & 1) && this_round > 0) {
396                                         char c;
397
398                                         this_round--;
399                                         c = *con_buf0++;
400 #ifdef __BIG_ENDIAN
401                                         vcs_scr_writew(vc, c |
402                                              (vcs_scr_readw(vc, org) & 0xff00), org);
403 #else
404                                         vcs_scr_writew(vc, (c << 8) |
405                                              (vcs_scr_readw(vc, org) & 0xff), org);
406 #endif
407                                         org++;
408                                         p++;
409                                         if (++col == maxcol) {
410                                                 org = screen_pos(vc, p/2, viewed);
411                                                 col = 0;
412                                         }
413                                 }
414                                 p /= 2;
415                                 p += maxcol - col;
416                         }
417                         while (this_round > 1) {
418                                 unsigned short w;
419
420                                 w = get_unaligned(((unsigned short *)con_buf0));
421                                 vcs_scr_writew(vc, w, org++);
422                                 con_buf0 += 2;
423                                 this_round -= 2;
424                                 if (++col == maxcol) {
425                                         org = screen_pos(vc, p, viewed);
426                                         col = 0;
427                                         p += maxcol;
428                                 }
429                         }
430                         if (this_round > 0) {
431                                 unsigned char c;
432
433                                 c = *con_buf0++;
434 #ifdef __BIG_ENDIAN
435                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org);
436 #else
437                                 vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org);
438 #endif
439                         }
440                 }
441                 count -= orig_count;
442                 written += orig_count;
443                 buf += orig_count;
444                 pos += orig_count;
445                 if (org0)
446                         update_region(vc, (unsigned long)(org0), org - org0);
447         }
448         *ppos += written;
449         ret = written;
450
451 unlock_out:
452         release_console_sem();
453
454         up(&con_buf_sem);
455
456         return ret;
457 }
458
459 static int
460 vcs_open(struct inode *inode, struct file *filp)
461 {
462         unsigned int currcons = iminor(inode) & 127;
463         if(currcons && !vc_cons_allocated(currcons-1))
464                 return -ENXIO;
465         return 0;
466 }
467
468 static const struct file_operations vcs_fops = {
469         .llseek         = vcs_lseek,
470         .read           = vcs_read,
471         .write          = vcs_write,
472         .open           = vcs_open,
473 };
474
475 static struct class *vc_class;
476
477 void vcs_make_sysfs(struct tty_struct *tty)
478 {
479         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1),
480                         "vcs%u", tty->index + 1);
481         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129),
482                         "vcsa%u", tty->index + 1);
483 }
484
485 void vcs_remove_sysfs(struct tty_struct *tty)
486 {
487         device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1));
488         device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129));
489 }
490
491 int __init vcs_init(void)
492 {
493         if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops))
494                 panic("unable to get major %d for vcs device", VCS_MAJOR);
495         vc_class = class_create(THIS_MODULE, "vc");
496
497         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), "vcs");
498         device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), "vcsa");
499         return 0;
500 }