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-rw-r--r--drivers/char/vc_screen.c509
1 files changed, 509 insertions, 0 deletions
diff --git a/drivers/char/vc_screen.c b/drivers/char/vc_screen.c
new file mode 100644
index 000000000000..7abe405b8657
--- /dev/null
+++ b/drivers/char/vc_screen.c
@@ -0,0 +1,509 @@
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
49static int
50vcs_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
72static 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
100static ssize_t
101vcs_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;
267unlock_out:
268 release_console_sem();
269 up(&con_buf_sem);
270 return ret;
271}
272
273static ssize_t
274vcs_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
453unlock_out:
454 release_console_sem();
455
456 up(&con_buf_sem);
457
458 return ret;
459}
460
461static int
462vcs_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
470static struct file_operations vcs_fops = {
471 .llseek = vcs_lseek,
472 .read = vcs_read,
473 .write = vcs_write,
474 .open = vcs_open,
475};
476
477static struct class_simple *vc_class;
478
479void 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}
490void 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
498int __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}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-29 03:59:44 -0500