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Commit | Line | Data |
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1da177e4 LT |
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/config.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/major.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/tty.h> | |
29 | #include <linux/devfs_fs_kernel.h> | |
30 | #include <linux/sched.h> | |
31 | #include <linux/interrupt.h> | |
32 | #include <linux/mm.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/vt_kern.h> | |
35 | #include <linux/selection.h> | |
36 | #include <linux/kbd_kern.h> | |
37 | #include <linux/console.h> | |
38 | #include <linux/smp_lock.h> | |
39 | #include <linux/device.h> | |
40 | #include <asm/uaccess.h> | |
41 | #include <asm/byteorder.h> | |
42 | #include <asm/unaligned.h> | |
43 | ||
44 | #undef attr | |
45 | #undef org | |
46 | #undef addr | |
47 | #define HEADER_SIZE 4 | |
48 | ||
49 | static int | |
50 | vcs_size(struct inode *inode) | |
51 | { | |
52 | int size; | |
53 | int minor = iminor(inode); | |
54 | int currcons = minor & 127; | |
55 | struct vc_data *vc; | |
56 | ||
57 | if (currcons == 0) | |
58 | currcons = fg_console; | |
59 | else | |
60 | currcons--; | |
61 | if (!vc_cons_allocated(currcons)) | |
62 | return -ENXIO; | |
63 | vc = vc_cons[currcons].d; | |
64 | ||
65 | size = vc->vc_rows * vc->vc_cols; | |
66 | ||
67 | if (minor & 128) | |
68 | size = 2*size + HEADER_SIZE; | |
69 | return size; | |
70 | } | |
71 | ||
72 | static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) | |
73 | { | |
74 | int size; | |
75 | ||
76 | down(&con_buf_sem); | |
77 | size = vcs_size(file->f_dentry->d_inode); | |
78 | switch (orig) { | |
79 | default: | |
80 | up(&con_buf_sem); | |
81 | return -EINVAL; | |
82 | case 2: | |
83 | offset += size; | |
84 | break; | |
85 | case 1: | |
86 | offset += file->f_pos; | |
87 | case 0: | |
88 | break; | |
89 | } | |
90 | if (offset < 0 || offset > size) { | |
91 | up(&con_buf_sem); | |
92 | return -EINVAL; | |
93 | } | |
94 | file->f_pos = offset; | |
95 | up(&con_buf_sem); | |
96 | return file->f_pos; | |
97 | } | |
98 | ||
99 | ||
100 | static ssize_t | |
101 | vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
102 | { | |
103 | struct inode *inode = file->f_dentry->d_inode; | |
104 | unsigned int currcons = iminor(inode); | |
105 | struct vc_data *vc; | |
106 | long pos; | |
107 | long viewed, attr, read; | |
108 | int col, maxcol; | |
109 | unsigned short *org = NULL; | |
110 | ssize_t ret; | |
111 | ||
112 | down(&con_buf_sem); | |
113 | ||
114 | pos = *ppos; | |
115 | ||
116 | /* Select the proper current console and verify | |
117 | * sanity of the situation under the console lock. | |
118 | */ | |
119 | acquire_console_sem(); | |
120 | ||
121 | attr = (currcons & 128); | |
122 | currcons = (currcons & 127); | |
123 | if (currcons == 0) { | |
124 | currcons = fg_console; | |
125 | viewed = 1; | |
126 | } else { | |
127 | currcons--; | |
128 | viewed = 0; | |
129 | } | |
130 | ret = -ENXIO; | |
131 | if (!vc_cons_allocated(currcons)) | |
132 | goto unlock_out; | |
133 | vc = vc_cons[currcons].d; | |
134 | ||
135 | ret = -EINVAL; | |
136 | if (pos < 0) | |
137 | goto unlock_out; | |
138 | read = 0; | |
139 | ret = 0; | |
140 | while (count) { | |
141 | char *con_buf0, *con_buf_start; | |
142 | long this_round, size; | |
143 | ssize_t orig_count; | |
144 | long p = pos; | |
145 | ||
146 | /* Check whether we are above size each round, | |
147 | * as copy_to_user at the end of this loop | |
148 | * could sleep. | |
149 | */ | |
150 | size = vcs_size(inode); | |
151 | if (pos >= size) | |
152 | break; | |
153 | if (count > size - pos) | |
154 | count = size - pos; | |
155 | ||
156 | this_round = count; | |
157 | if (this_round > CON_BUF_SIZE) | |
158 | this_round = CON_BUF_SIZE; | |
159 | ||
160 | /* Perform the whole read into the local con_buf. | |
161 | * Then we can drop the console spinlock and safely | |
162 | * attempt to move it to userspace. | |
163 | */ | |
164 | ||
165 | con_buf_start = con_buf0 = con_buf; | |
166 | orig_count = this_round; | |
167 | maxcol = vc->vc_cols; | |
168 | if (!attr) { | |
169 | org = screen_pos(vc, p, viewed); | |
170 | col = p % maxcol; | |
171 | p += maxcol - col; | |
172 | while (this_round-- > 0) { | |
173 | *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff); | |
174 | if (++col == maxcol) { | |
175 | org = screen_pos(vc, p, viewed); | |
176 | col = 0; | |
177 | p += maxcol; | |
178 | } | |
179 | } | |
180 | } else { | |
181 | if (p < HEADER_SIZE) { | |
182 | size_t tmp_count; | |
183 | ||
184 | con_buf0[0] = (char)vc->vc_rows; | |
185 | con_buf0[1] = (char)vc->vc_cols; | |
186 | getconsxy(vc, con_buf0 + 2); | |
187 | ||
188 | con_buf_start += p; | |
189 | this_round += p; | |
190 | if (this_round > CON_BUF_SIZE) { | |
191 | this_round = CON_BUF_SIZE; | |
192 | orig_count = this_round - p; | |
193 | } | |
194 | ||
195 | tmp_count = HEADER_SIZE; | |
196 | if (tmp_count > this_round) | |
197 | tmp_count = this_round; | |
198 | ||
199 | /* Advance state pointers and move on. */ | |
200 | this_round -= tmp_count; | |
201 | p = HEADER_SIZE; | |
202 | con_buf0 = con_buf + HEADER_SIZE; | |
203 | /* If this_round >= 0, then p is even... */ | |
204 | } else if (p & 1) { | |
205 | /* Skip first byte for output if start address is odd | |
206 | * Update region sizes up/down depending on free | |
207 | * space in buffer. | |
208 | */ | |
209 | con_buf_start++; | |
210 | if (this_round < CON_BUF_SIZE) | |
211 | this_round++; | |
212 | else | |
213 | orig_count--; | |
214 | } | |
215 | if (this_round > 0) { | |
216 | unsigned short *tmp_buf = (unsigned short *)con_buf0; | |
217 | ||
218 | p -= HEADER_SIZE; | |
219 | p /= 2; | |
220 | col = p % maxcol; | |
221 | ||
222 | org = screen_pos(vc, p, viewed); | |
223 | p += maxcol - col; | |
224 | ||
225 | /* Buffer has even length, so we can always copy | |
226 | * character + attribute. We do not copy last byte | |
227 | * to userspace if this_round is odd. | |
228 | */ | |
229 | this_round = (this_round + 1) >> 1; | |
230 | ||
231 | while (this_round) { | |
232 | *tmp_buf++ = vcs_scr_readw(vc, org++); | |
233 | this_round --; | |
234 | if (++col == maxcol) { | |
235 | org = screen_pos(vc, p, viewed); | |
236 | col = 0; | |
237 | p += maxcol; | |
238 | } | |
239 | } | |
240 | } | |
241 | } | |
242 | ||
243 | /* Finally, release the console semaphore while we push | |
244 | * all the data to userspace from our temporary buffer. | |
245 | * | |
246 | * AKPM: Even though it's a semaphore, we should drop it because | |
247 | * the pagefault handling code may want to call printk(). | |
248 | */ | |
249 | ||
250 | release_console_sem(); | |
251 | ret = copy_to_user(buf, con_buf_start, orig_count); | |
252 | acquire_console_sem(); | |
253 | ||
254 | if (ret) { | |
255 | read += (orig_count - ret); | |
256 | ret = -EFAULT; | |
257 | break; | |
258 | } | |
259 | buf += orig_count; | |
260 | pos += orig_count; | |
261 | read += orig_count; | |
262 | count -= orig_count; | |
263 | } | |
264 | *ppos += read; | |
265 | if (read) | |
266 | ret = read; | |
267 | unlock_out: | |
268 | release_console_sem(); | |
269 | up(&con_buf_sem); | |
270 | return ret; | |
271 | } | |
272 | ||
273 | static ssize_t | |
274 | vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
275 | { | |
276 | struct inode *inode = file->f_dentry->d_inode; | |
277 | unsigned int currcons = iminor(inode); | |
278 | struct vc_data *vc; | |
279 | long pos; | |
280 | long viewed, attr, size, written; | |
281 | char *con_buf0; | |
282 | int col, maxcol; | |
283 | u16 *org0 = NULL, *org = NULL; | |
284 | size_t ret; | |
285 | ||
286 | down(&con_buf_sem); | |
287 | ||
288 | pos = *ppos; | |
289 | ||
290 | /* Select the proper current console and verify | |
291 | * sanity of the situation under the console lock. | |
292 | */ | |
293 | acquire_console_sem(); | |
294 | ||
295 | attr = (currcons & 128); | |
296 | currcons = (currcons & 127); | |
297 | ||
298 | if (currcons == 0) { | |
299 | currcons = fg_console; | |
300 | viewed = 1; | |
301 | } else { | |
302 | currcons--; | |
303 | viewed = 0; | |
304 | } | |
305 | ret = -ENXIO; | |
306 | if (!vc_cons_allocated(currcons)) | |
307 | goto unlock_out; | |
308 | vc = vc_cons[currcons].d; | |
309 | ||
310 | size = vcs_size(inode); | |
311 | ret = -EINVAL; | |
312 | if (pos < 0 || pos > size) | |
313 | goto unlock_out; | |
314 | if (count > size - pos) | |
315 | count = size - pos; | |
316 | written = 0; | |
317 | while (count) { | |
318 | long this_round = count; | |
319 | size_t orig_count; | |
320 | long p; | |
321 | ||
322 | if (this_round > CON_BUF_SIZE) | |
323 | this_round = CON_BUF_SIZE; | |
324 | ||
325 | /* Temporarily drop the console lock so that we can read | |
326 | * in the write data from userspace safely. | |
327 | */ | |
328 | release_console_sem(); | |
329 | ret = copy_from_user(con_buf, buf, this_round); | |
330 | acquire_console_sem(); | |
331 | ||
332 | if (ret) { | |
333 | this_round -= ret; | |
334 | if (!this_round) { | |
335 | /* Abort loop if no data were copied. Otherwise | |
336 | * fail with -EFAULT. | |
337 | */ | |
338 | if (written) | |
339 | break; | |
340 | ret = -EFAULT; | |
341 | goto unlock_out; | |
342 | } | |
343 | } | |
344 | ||
345 | /* The vcs_size might have changed while we slept to grab | |
346 | * the user buffer, so recheck. | |
347 | * Return data written up to now on failure. | |
348 | */ | |
349 | size = vcs_size(inode); | |
350 | if (pos >= size) | |
351 | break; | |
352 | if (this_round > size - pos) | |
353 | this_round = size - pos; | |
354 | ||
355 | /* OK, now actually push the write to the console | |
356 | * under the lock using the local kernel buffer. | |
357 | */ | |
358 | ||
359 | con_buf0 = con_buf; | |
360 | orig_count = this_round; | |
361 | maxcol = vc->vc_cols; | |
362 | p = pos; | |
363 | if (!attr) { | |
364 | org0 = org = screen_pos(vc, p, viewed); | |
365 | col = p % maxcol; | |
366 | p += maxcol - col; | |
367 | ||
368 | while (this_round > 0) { | |
369 | unsigned char c = *con_buf0++; | |
370 | ||
371 | this_round--; | |
372 | vcs_scr_writew(vc, | |
373 | (vcs_scr_readw(vc, org) & 0xff00) | c, org); | |
374 | org++; | |
375 | if (++col == maxcol) { | |
376 | org = screen_pos(vc, p, viewed); | |
377 | col = 0; | |
378 | p += maxcol; | |
379 | } | |
380 | } | |
381 | } else { | |
382 | if (p < HEADER_SIZE) { | |
383 | char header[HEADER_SIZE]; | |
384 | ||
385 | getconsxy(vc, header + 2); | |
386 | while (p < HEADER_SIZE && this_round > 0) { | |
387 | this_round--; | |
388 | header[p++] = *con_buf0++; | |
389 | } | |
390 | if (!viewed) | |
391 | putconsxy(vc, header + 2); | |
392 | } | |
393 | p -= HEADER_SIZE; | |
394 | col = (p/2) % maxcol; | |
395 | if (this_round > 0) { | |
396 | org0 = org = screen_pos(vc, p/2, viewed); | |
397 | if ((p & 1) && this_round > 0) { | |
398 | char c; | |
399 | ||
400 | this_round--; | |
401 | c = *con_buf0++; | |
402 | #ifdef __BIG_ENDIAN | |
403 | vcs_scr_writew(vc, c | | |
404 | (vcs_scr_readw(vc, org) & 0xff00), org); | |
405 | #else | |
406 | vcs_scr_writew(vc, (c << 8) | | |
407 | (vcs_scr_readw(vc, org) & 0xff), org); | |
408 | #endif | |
409 | org++; | |
410 | p++; | |
411 | if (++col == maxcol) { | |
412 | org = screen_pos(vc, p/2, viewed); | |
413 | col = 0; | |
414 | } | |
415 | } | |
416 | p /= 2; | |
417 | p += maxcol - col; | |
418 | } | |
419 | while (this_round > 1) { | |
420 | unsigned short w; | |
421 | ||
422 | w = get_unaligned(((const unsigned short *)con_buf0)); | |
423 | vcs_scr_writew(vc, w, org++); | |
424 | con_buf0 += 2; | |
425 | this_round -= 2; | |
426 | if (++col == maxcol) { | |
427 | org = screen_pos(vc, p, viewed); | |
428 | col = 0; | |
429 | p += maxcol; | |
430 | } | |
431 | } | |
432 | if (this_round > 0) { | |
433 | unsigned char c; | |
434 | ||
435 | c = *con_buf0++; | |
436 | #ifdef __BIG_ENDIAN | |
437 | vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org); | |
438 | #else | |
439 | vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org); | |
440 | #endif | |
441 | } | |
442 | } | |
443 | count -= orig_count; | |
444 | written += orig_count; | |
445 | buf += orig_count; | |
446 | pos += orig_count; | |
447 | if (org0) | |
448 | update_region(vc, (unsigned long)(org0), org - org0); | |
449 | } | |
450 | *ppos += written; | |
451 | ret = written; | |
452 | ||
453 | unlock_out: | |
454 | release_console_sem(); | |
455 | ||
456 | up(&con_buf_sem); | |
457 | ||
458 | return ret; | |
459 | } | |
460 | ||
461 | static int | |
462 | vcs_open(struct inode *inode, struct file *filp) | |
463 | { | |
464 | unsigned int currcons = iminor(inode) & 127; | |
465 | if(currcons && !vc_cons_allocated(currcons-1)) | |
466 | return -ENXIO; | |
467 | return 0; | |
468 | } | |
469 | ||
470 | static struct file_operations vcs_fops = { | |
471 | .llseek = vcs_lseek, | |
472 | .read = vcs_read, | |
473 | .write = vcs_write, | |
474 | .open = vcs_open, | |
475 | }; | |
476 | ||
ca8eca68 | 477 | static struct class *vc_class; |
1da177e4 LT |
478 | |
479 | void vcs_make_devfs(struct tty_struct *tty) | |
480 | { | |
481 | devfs_mk_cdev(MKDEV(VCS_MAJOR, tty->index + 1), | |
482 | S_IFCHR|S_IRUSR|S_IWUSR, | |
483 | "vcc/%u", tty->index + 1); | |
484 | devfs_mk_cdev(MKDEV(VCS_MAJOR, tty->index + 129), | |
485 | S_IFCHR|S_IRUSR|S_IWUSR, | |
486 | "vcc/a%u", tty->index + 1); | |
53f46542 GKH |
487 | class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1), |
488 | NULL, "vcs%u", tty->index + 1); | |
489 | class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129), | |
490 | NULL, "vcsa%u", tty->index + 1); | |
1da177e4 LT |
491 | } |
492 | void vcs_remove_devfs(struct tty_struct *tty) | |
493 | { | |
494 | devfs_remove("vcc/%u", tty->index + 1); | |
495 | devfs_remove("vcc/a%u", tty->index + 1); | |
ca8eca68 GKH |
496 | class_device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1)); |
497 | class_device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129)); | |
1da177e4 LT |
498 | } |
499 | ||
500 | int __init vcs_init(void) | |
501 | { | |
502 | if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops)) | |
503 | panic("unable to get major %d for vcs device", VCS_MAJOR); | |
ca8eca68 | 504 | vc_class = class_create(THIS_MODULE, "vc"); |
1da177e4 LT |
505 | |
506 | devfs_mk_cdev(MKDEV(VCS_MAJOR, 0), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/0"); | |
507 | devfs_mk_cdev(MKDEV(VCS_MAJOR, 128), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/a0"); | |
53f46542 GKH |
508 | class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs"); |
509 | class_device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa"); | |
1da177e4 LT |
510 | return 0; |
511 | } |