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 | ||
1da177e4 LT |
24 | #include <linux/kernel.h> |
25 | #include <linux/major.h> | |
26 | #include <linux/errno.h> | |
27 | #include <linux/tty.h> | |
1da177e4 LT |
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/smp_lock.h> | |
36 | #include <linux/device.h> | |
37 | #include <asm/uaccess.h> | |
38 | #include <asm/byteorder.h> | |
39 | #include <asm/unaligned.h> | |
40 | ||
41 | #undef attr | |
42 | #undef org | |
43 | #undef addr | |
44 | #define HEADER_SIZE 4 | |
45 | ||
46 | static int | |
47 | vcs_size(struct inode *inode) | |
48 | { | |
49 | int size; | |
50 | int minor = iminor(inode); | |
51 | int currcons = minor & 127; | |
52 | struct vc_data *vc; | |
53 | ||
54 | if (currcons == 0) | |
55 | currcons = fg_console; | |
56 | else | |
57 | currcons--; | |
58 | if (!vc_cons_allocated(currcons)) | |
59 | return -ENXIO; | |
60 | vc = vc_cons[currcons].d; | |
61 | ||
62 | size = vc->vc_rows * vc->vc_cols; | |
63 | ||
64 | if (minor & 128) | |
65 | size = 2*size + HEADER_SIZE; | |
66 | return size; | |
67 | } | |
68 | ||
69 | static loff_t vcs_lseek(struct file *file, loff_t offset, int orig) | |
70 | { | |
71 | int size; | |
72 | ||
73 | down(&con_buf_sem); | |
a7113a96 | 74 | size = vcs_size(file->f_path.dentry->d_inode); |
1da177e4 LT |
75 | switch (orig) { |
76 | default: | |
77 | up(&con_buf_sem); | |
78 | return -EINVAL; | |
79 | case 2: | |
80 | offset += size; | |
81 | break; | |
82 | case 1: | |
83 | offset += file->f_pos; | |
84 | case 0: | |
85 | break; | |
86 | } | |
87 | if (offset < 0 || offset > size) { | |
88 | up(&con_buf_sem); | |
89 | return -EINVAL; | |
90 | } | |
91 | file->f_pos = offset; | |
92 | up(&con_buf_sem); | |
93 | return file->f_pos; | |
94 | } | |
95 | ||
96 | ||
97 | static ssize_t | |
98 | vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
99 | { | |
a7113a96 | 100 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
101 | unsigned int currcons = iminor(inode); |
102 | struct vc_data *vc; | |
103 | long pos; | |
104 | long viewed, attr, read; | |
105 | int col, maxcol; | |
106 | unsigned short *org = NULL; | |
107 | ssize_t ret; | |
108 | ||
109 | down(&con_buf_sem); | |
110 | ||
111 | pos = *ppos; | |
112 | ||
113 | /* Select the proper current console and verify | |
114 | * sanity of the situation under the console lock. | |
115 | */ | |
116 | acquire_console_sem(); | |
117 | ||
118 | attr = (currcons & 128); | |
119 | currcons = (currcons & 127); | |
120 | if (currcons == 0) { | |
121 | currcons = fg_console; | |
122 | viewed = 1; | |
123 | } else { | |
124 | currcons--; | |
125 | viewed = 0; | |
126 | } | |
127 | ret = -ENXIO; | |
128 | if (!vc_cons_allocated(currcons)) | |
129 | goto unlock_out; | |
130 | vc = vc_cons[currcons].d; | |
131 | ||
132 | ret = -EINVAL; | |
133 | if (pos < 0) | |
134 | goto unlock_out; | |
135 | read = 0; | |
136 | ret = 0; | |
137 | while (count) { | |
138 | char *con_buf0, *con_buf_start; | |
139 | long this_round, size; | |
140 | ssize_t orig_count; | |
141 | long p = pos; | |
142 | ||
143 | /* Check whether we are above size each round, | |
144 | * as copy_to_user at the end of this loop | |
145 | * could sleep. | |
146 | */ | |
147 | size = vcs_size(inode); | |
148 | if (pos >= size) | |
149 | break; | |
150 | if (count > size - pos) | |
151 | count = size - pos; | |
152 | ||
153 | this_round = count; | |
154 | if (this_round > CON_BUF_SIZE) | |
155 | this_round = CON_BUF_SIZE; | |
156 | ||
157 | /* Perform the whole read into the local con_buf. | |
158 | * Then we can drop the console spinlock and safely | |
159 | * attempt to move it to userspace. | |
160 | */ | |
161 | ||
162 | con_buf_start = con_buf0 = con_buf; | |
163 | orig_count = this_round; | |
164 | maxcol = vc->vc_cols; | |
165 | if (!attr) { | |
166 | org = screen_pos(vc, p, viewed); | |
167 | col = p % maxcol; | |
168 | p += maxcol - col; | |
169 | while (this_round-- > 0) { | |
170 | *con_buf0++ = (vcs_scr_readw(vc, org++) & 0xff); | |
171 | if (++col == maxcol) { | |
172 | org = screen_pos(vc, p, viewed); | |
173 | col = 0; | |
174 | p += maxcol; | |
175 | } | |
176 | } | |
177 | } else { | |
178 | if (p < HEADER_SIZE) { | |
179 | size_t tmp_count; | |
180 | ||
181 | con_buf0[0] = (char)vc->vc_rows; | |
182 | con_buf0[1] = (char)vc->vc_cols; | |
183 | getconsxy(vc, con_buf0 + 2); | |
184 | ||
185 | con_buf_start += p; | |
186 | this_round += p; | |
187 | if (this_round > CON_BUF_SIZE) { | |
188 | this_round = CON_BUF_SIZE; | |
189 | orig_count = this_round - p; | |
190 | } | |
191 | ||
192 | tmp_count = HEADER_SIZE; | |
193 | if (tmp_count > this_round) | |
194 | tmp_count = this_round; | |
195 | ||
196 | /* Advance state pointers and move on. */ | |
197 | this_round -= tmp_count; | |
198 | p = HEADER_SIZE; | |
199 | con_buf0 = con_buf + HEADER_SIZE; | |
200 | /* If this_round >= 0, then p is even... */ | |
201 | } else if (p & 1) { | |
202 | /* Skip first byte for output if start address is odd | |
203 | * Update region sizes up/down depending on free | |
204 | * space in buffer. | |
205 | */ | |
206 | con_buf_start++; | |
207 | if (this_round < CON_BUF_SIZE) | |
208 | this_round++; | |
209 | else | |
210 | orig_count--; | |
211 | } | |
212 | if (this_round > 0) { | |
213 | unsigned short *tmp_buf = (unsigned short *)con_buf0; | |
214 | ||
215 | p -= HEADER_SIZE; | |
216 | p /= 2; | |
217 | col = p % maxcol; | |
218 | ||
219 | org = screen_pos(vc, p, viewed); | |
220 | p += maxcol - col; | |
221 | ||
222 | /* Buffer has even length, so we can always copy | |
223 | * character + attribute. We do not copy last byte | |
224 | * to userspace if this_round is odd. | |
225 | */ | |
226 | this_round = (this_round + 1) >> 1; | |
227 | ||
228 | while (this_round) { | |
229 | *tmp_buf++ = vcs_scr_readw(vc, org++); | |
230 | this_round --; | |
231 | if (++col == maxcol) { | |
232 | org = screen_pos(vc, p, viewed); | |
233 | col = 0; | |
234 | p += maxcol; | |
235 | } | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
240 | /* Finally, release the console semaphore while we push | |
241 | * all the data to userspace from our temporary buffer. | |
242 | * | |
243 | * AKPM: Even though it's a semaphore, we should drop it because | |
244 | * the pagefault handling code may want to call printk(). | |
245 | */ | |
246 | ||
247 | release_console_sem(); | |
248 | ret = copy_to_user(buf, con_buf_start, orig_count); | |
249 | acquire_console_sem(); | |
250 | ||
251 | if (ret) { | |
252 | read += (orig_count - ret); | |
253 | ret = -EFAULT; | |
254 | break; | |
255 | } | |
256 | buf += orig_count; | |
257 | pos += orig_count; | |
258 | read += orig_count; | |
259 | count -= orig_count; | |
260 | } | |
261 | *ppos += read; | |
262 | if (read) | |
263 | ret = read; | |
264 | unlock_out: | |
265 | release_console_sem(); | |
266 | up(&con_buf_sem); | |
267 | return ret; | |
268 | } | |
269 | ||
270 | static ssize_t | |
271 | vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
272 | { | |
a7113a96 | 273 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
274 | unsigned int currcons = iminor(inode); |
275 | struct vc_data *vc; | |
276 | long pos; | |
277 | long viewed, attr, size, written; | |
278 | char *con_buf0; | |
279 | int col, maxcol; | |
280 | u16 *org0 = NULL, *org = NULL; | |
281 | size_t ret; | |
282 | ||
283 | down(&con_buf_sem); | |
284 | ||
285 | pos = *ppos; | |
286 | ||
287 | /* Select the proper current console and verify | |
288 | * sanity of the situation under the console lock. | |
289 | */ | |
290 | acquire_console_sem(); | |
291 | ||
292 | attr = (currcons & 128); | |
293 | currcons = (currcons & 127); | |
294 | ||
295 | if (currcons == 0) { | |
296 | currcons = fg_console; | |
297 | viewed = 1; | |
298 | } else { | |
299 | currcons--; | |
300 | viewed = 0; | |
301 | } | |
302 | ret = -ENXIO; | |
303 | if (!vc_cons_allocated(currcons)) | |
304 | goto unlock_out; | |
305 | vc = vc_cons[currcons].d; | |
306 | ||
307 | size = vcs_size(inode); | |
308 | ret = -EINVAL; | |
309 | if (pos < 0 || pos > size) | |
310 | goto unlock_out; | |
311 | if (count > size - pos) | |
312 | count = size - pos; | |
313 | written = 0; | |
314 | while (count) { | |
315 | long this_round = count; | |
316 | size_t orig_count; | |
317 | long p; | |
318 | ||
319 | if (this_round > CON_BUF_SIZE) | |
320 | this_round = CON_BUF_SIZE; | |
321 | ||
322 | /* Temporarily drop the console lock so that we can read | |
323 | * in the write data from userspace safely. | |
324 | */ | |
325 | release_console_sem(); | |
326 | ret = copy_from_user(con_buf, buf, this_round); | |
327 | acquire_console_sem(); | |
328 | ||
329 | if (ret) { | |
330 | this_round -= ret; | |
331 | if (!this_round) { | |
332 | /* Abort loop if no data were copied. Otherwise | |
333 | * fail with -EFAULT. | |
334 | */ | |
335 | if (written) | |
336 | break; | |
337 | ret = -EFAULT; | |
338 | goto unlock_out; | |
339 | } | |
340 | } | |
341 | ||
342 | /* The vcs_size might have changed while we slept to grab | |
343 | * the user buffer, so recheck. | |
344 | * Return data written up to now on failure. | |
345 | */ | |
346 | size = vcs_size(inode); | |
347 | if (pos >= size) | |
348 | break; | |
349 | if (this_round > size - pos) | |
350 | this_round = size - pos; | |
351 | ||
352 | /* OK, now actually push the write to the console | |
353 | * under the lock using the local kernel buffer. | |
354 | */ | |
355 | ||
356 | con_buf0 = con_buf; | |
357 | orig_count = this_round; | |
358 | maxcol = vc->vc_cols; | |
359 | p = pos; | |
360 | if (!attr) { | |
361 | org0 = org = screen_pos(vc, p, viewed); | |
362 | col = p % maxcol; | |
363 | p += maxcol - col; | |
364 | ||
365 | while (this_round > 0) { | |
366 | unsigned char c = *con_buf0++; | |
367 | ||
368 | this_round--; | |
369 | vcs_scr_writew(vc, | |
370 | (vcs_scr_readw(vc, org) & 0xff00) | c, org); | |
371 | org++; | |
372 | if (++col == maxcol) { | |
373 | org = screen_pos(vc, p, viewed); | |
374 | col = 0; | |
375 | p += maxcol; | |
376 | } | |
377 | } | |
378 | } else { | |
379 | if (p < HEADER_SIZE) { | |
380 | char header[HEADER_SIZE]; | |
381 | ||
382 | getconsxy(vc, header + 2); | |
383 | while (p < HEADER_SIZE && this_round > 0) { | |
384 | this_round--; | |
385 | header[p++] = *con_buf0++; | |
386 | } | |
387 | if (!viewed) | |
388 | putconsxy(vc, header + 2); | |
389 | } | |
390 | p -= HEADER_SIZE; | |
391 | col = (p/2) % maxcol; | |
392 | if (this_round > 0) { | |
393 | org0 = org = screen_pos(vc, p/2, viewed); | |
394 | if ((p & 1) && this_round > 0) { | |
395 | char c; | |
396 | ||
397 | this_round--; | |
398 | c = *con_buf0++; | |
399 | #ifdef __BIG_ENDIAN | |
400 | vcs_scr_writew(vc, c | | |
401 | (vcs_scr_readw(vc, org) & 0xff00), org); | |
402 | #else | |
403 | vcs_scr_writew(vc, (c << 8) | | |
404 | (vcs_scr_readw(vc, org) & 0xff), org); | |
405 | #endif | |
406 | org++; | |
407 | p++; | |
408 | if (++col == maxcol) { | |
409 | org = screen_pos(vc, p/2, viewed); | |
410 | col = 0; | |
411 | } | |
412 | } | |
413 | p /= 2; | |
414 | p += maxcol - col; | |
415 | } | |
416 | while (this_round > 1) { | |
417 | unsigned short w; | |
418 | ||
ee025949 | 419 | w = get_unaligned(((unsigned short *)con_buf0)); |
1da177e4 LT |
420 | vcs_scr_writew(vc, w, org++); |
421 | con_buf0 += 2; | |
422 | this_round -= 2; | |
423 | if (++col == maxcol) { | |
424 | org = screen_pos(vc, p, viewed); | |
425 | col = 0; | |
426 | p += maxcol; | |
427 | } | |
428 | } | |
429 | if (this_round > 0) { | |
430 | unsigned char c; | |
431 | ||
432 | c = *con_buf0++; | |
433 | #ifdef __BIG_ENDIAN | |
434 | vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff) | (c << 8), org); | |
435 | #else | |
436 | vcs_scr_writew(vc, (vcs_scr_readw(vc, org) & 0xff00) | c, org); | |
437 | #endif | |
438 | } | |
439 | } | |
440 | count -= orig_count; | |
441 | written += orig_count; | |
442 | buf += orig_count; | |
443 | pos += orig_count; | |
444 | if (org0) | |
445 | update_region(vc, (unsigned long)(org0), org - org0); | |
446 | } | |
447 | *ppos += written; | |
448 | ret = written; | |
449 | ||
450 | unlock_out: | |
451 | release_console_sem(); | |
452 | ||
453 | up(&con_buf_sem); | |
454 | ||
455 | return ret; | |
456 | } | |
457 | ||
458 | static int | |
459 | vcs_open(struct inode *inode, struct file *filp) | |
460 | { | |
461 | unsigned int currcons = iminor(inode) & 127; | |
462 | if(currcons && !vc_cons_allocated(currcons-1)) | |
463 | return -ENXIO; | |
464 | return 0; | |
465 | } | |
466 | ||
62322d25 | 467 | static const struct file_operations vcs_fops = { |
1da177e4 LT |
468 | .llseek = vcs_lseek, |
469 | .read = vcs_read, | |
470 | .write = vcs_write, | |
471 | .open = vcs_open, | |
472 | }; | |
473 | ||
ca8eca68 | 474 | static struct class *vc_class; |
1da177e4 | 475 | |
d09d7ddf | 476 | void vcs_make_sysfs(struct tty_struct *tty) |
1da177e4 | 477 | { |
cd15422b GKH |
478 | device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 1), |
479 | "vcs%u", tty->index + 1); | |
480 | device_create(vc_class, NULL, MKDEV(VCS_MAJOR, tty->index + 129), | |
481 | "vcsa%u", tty->index + 1); | |
1da177e4 | 482 | } |
d09d7ddf AC |
483 | |
484 | void vcs_remove_sysfs(struct tty_struct *tty) | |
1da177e4 | 485 | { |
cd15422b GKH |
486 | device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 1)); |
487 | device_destroy(vc_class, MKDEV(VCS_MAJOR, tty->index + 129)); | |
1da177e4 LT |
488 | } |
489 | ||
490 | int __init vcs_init(void) | |
491 | { | |
492 | if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops)) | |
493 | panic("unable to get major %d for vcs device", VCS_MAJOR); | |
ca8eca68 | 494 | vc_class = class_create(THIS_MODULE, "vc"); |
1da177e4 | 495 | |
cd15422b GKH |
496 | device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), "vcs"); |
497 | device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), "vcsa"); | |
1da177e4 LT |
498 | return 0; |
499 | } |