Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/drivers/char/vc_screen.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 11713 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | |
477 | static struct class_simple *vc_class; |
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); |
487 | class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, tty->index + 1), NULL, "vcs%u", tty->index + 1); |
488 | class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, tty->index + 129), NULL, "vcsa%u", tty->index + 1); |
489 | } |
490 | void vcs_remove_devfs(struct tty_struct *tty) |
491 | { |
492 | devfs_remove("vcc/%u", tty->index + 1); |
493 | devfs_remove("vcc/a%u", tty->index + 1); |
494 | class_simple_device_remove(MKDEV(VCS_MAJOR, tty->index + 1)); |
495 | class_simple_device_remove(MKDEV(VCS_MAJOR, tty->index + 129)); |
496 | } |
497 | |
498 | int __init vcs_init(void) |
499 | { |
500 | if (register_chrdev(VCS_MAJOR, "vcs", &vcs_fops)) |
501 | panic("unable to get major %d for vcs device", VCS_MAJOR); |
502 | vc_class = class_simple_create(THIS_MODULE, "vc"); |
503 | |
504 | devfs_mk_cdev(MKDEV(VCS_MAJOR, 0), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/0"); |
505 | devfs_mk_cdev(MKDEV(VCS_MAJOR, 128), S_IFCHR|S_IRUSR|S_IWUSR, "vcc/a0"); |
506 | class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, 0), NULL, "vcs"); |
507 | class_simple_device_add(vc_class, MKDEV(VCS_MAJOR, 128), NULL, "vcsa"); |
508 | return 0; |
509 | } |