This source file includes following definitions.
- transfer_none
- transfer_xor
- transfer_des
- figure_loop_size
- do_lo_request
- loop_set_fd
- loop_clr_fd
- loop_set_status
- loop_get_status
- lo_ioctl
- lo_open
- lo_release
- loop_init
- cleanup_module
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16 #include <linux/module.h>
17
18 #include <linux/mm.h>
19 #include <linux/sched.h>
20 #include <linux/fs.h>
21 #include <linux/stat.h>
22 #include <linux/kernel.h>
23 #include <linux/string.h>
24 #include <linux/errno.h>
25 #include <asm/segment.h>
26 #include "loop.h"
27
28 #ifdef DES_AVAILABLE
29 #include "des.h"
30 #endif
31
32 #define DEFAULT_MAJOR_NR 28
33 int loop_major = DEFAULT_MAJOR_NR;
34 #define MAJOR_NR loop_major
35
36 #define DEVICE_NAME "loop"
37 #define DEVICE_REQUEST do_lo_request
38 #define DEVICE_NR(device) (MINOR(device))
39 #define DEVICE_ON(device)
40 #define DEVICE_OFF(device)
41 #define DEVICE_NO_RANDOM
42 #define TIMEOUT_VALUE (6 * HZ)
43 #include <linux/blk.h>
44
45 #define MAX_LOOP 8
46 static struct loop_device loop_dev[MAX_LOOP];
47 static int loop_sizes[MAX_LOOP];
48
49
50
51
52 static int transfer_none(struct loop_device *lo, int cmd, char *raw_buf,
53 char *loop_buf, int size)
54 {
55 if (cmd == READ)
56 memcpy(loop_buf, raw_buf, size);
57 else
58 memcpy(raw_buf, loop_buf, size);
59 return 0;
60 }
61
62 static int transfer_xor(struct loop_device *lo, int cmd, char *raw_buf,
63 char *loop_buf, int size)
64 {
65 char *in, *out, *key;
66 int i, keysize;
67
68 if (cmd == READ) {
69 in = raw_buf;
70 out = loop_buf;
71 } else {
72 in = loop_buf;
73 out = raw_buf;
74 }
75 key = lo->lo_encrypt_key;
76 keysize = lo->lo_encrypt_key_size;
77 for (i=0; i < size; i++)
78 *out++ = *in++ ^ key[(i & 511) % keysize];
79 return 0;
80 }
81
82 #ifdef DES_AVAILABLE
83 static int transfer_des(struct loop_device *lo, int cmd, char *raw_buf,
84 char *loop_buf, int size)
85 {
86 unsigned long tmp[2];
87 unsigned long x0,x1,p0,p1;
88
89 if (size & 7)
90 return -EINVAL;
91 x0 = lo->lo_des_init[0];
92 x1 = lo->lo_des_init[1];
93 while (size) {
94 if (cmd == READ) {
95 tmp[0] = (p0 = ((unsigned long *) raw_buf)[0])^x0;
96 tmp[1] = (p1 = ((unsigned long *) raw_buf)[1])^x1;
97 des_ecb_encrypt((des_cblock *) tmp,(des_cblock *)
98 loop_buf,lo->lo_des_key,DES_ENCRYPT);
99 x0 = p0^((unsigned long *) loop_buf)[0];
100 x1 = p1^((unsigned long *) loop_buf)[1];
101 }
102 else {
103 p0 = ((unsigned long *) loop_buf)[0];
104 p1 = ((unsigned long *) loop_buf)[1];
105 des_ecb_encrypt((des_cblock *) loop_buf,(des_cblock *)
106 raw_buf,lo->lo_des_key,DES_DECRYPT);
107 ((unsigned long *) raw_buf)[0] ^= x0;
108 ((unsigned long *) raw_buf)[1] ^= x1;
109 x0 = p0^((unsigned long *) raw_buf)[0];
110 x1 = p1^((unsigned long *) raw_buf)[1];
111 }
112 size -= 8;
113 raw_buf += 8;
114 loop_buf += 8;
115 }
116 return 0;
117 }
118 #endif
119
120 static transfer_proc_t xfer_funcs[MAX_LOOP] = {
121 transfer_none,
122 transfer_xor,
123 #ifdef DES_AVAILABLE
124 transfer_des,
125 #else
126 NULL,
127 #endif
128 0
129 };
130
131
132 #define MAX_DISK_SIZE 1024*1024*1024
133
134
135 static void figure_loop_size(struct loop_device *lo)
136 {
137 int size;
138
139 if (S_ISREG(lo->lo_inode->i_mode))
140 size = (lo->lo_inode->i_size - lo->lo_offset) / 1024;
141 else {
142 if (blk_size[MAJOR(lo->lo_device)])
143 size = ((blk_size[MAJOR(lo->lo_device)]
144 [MINOR(lo->lo_device)]) -
145 (lo->lo_offset/1024));
146 else
147 size = MAX_DISK_SIZE;
148 }
149 loop_sizes[lo->lo_number] = size;
150 }
151
152 static void do_lo_request(void)
153 {
154 int real_block, block, offset, len, blksize, size;
155 char *dest_addr;
156 struct loop_device *lo;
157 struct buffer_head *bh;
158
159 repeat:
160 INIT_REQUEST;
161 if (MINOR(CURRENT->rq_dev) >= MAX_LOOP)
162 goto error_out;
163 lo = &loop_dev[MINOR(CURRENT->rq_dev)];
164 if (!lo->lo_inode || !lo->transfer)
165 goto error_out;
166
167 blksize = BLOCK_SIZE;
168 if (blksize_size[MAJOR(lo->lo_device)]) {
169 blksize = blksize_size[MAJOR(lo->lo_device)][MINOR(lo->lo_device)];
170 if (!blksize)
171 blksize = BLOCK_SIZE;
172 }
173
174 dest_addr = CURRENT->buffer;
175
176 if (blksize < 512) {
177 block = CURRENT->sector * (512/blksize);
178 offset = 0;
179 } else {
180 block = CURRENT->sector / (blksize >> 9);
181 offset = CURRENT->sector % (blksize >> 9);
182 }
183 block += lo->lo_offset / blksize;
184 offset += lo->lo_offset % blksize;
185 if (offset > blksize) {
186 block++;
187 offset -= blksize;
188 }
189 len = CURRENT->current_nr_sectors << 9;
190 if ((CURRENT->cmd != WRITE) && (CURRENT->cmd != READ)) {
191 printk("unknown loop device command (%d)?!?", CURRENT->cmd);
192 goto error_out;
193 }
194 while (len > 0) {
195 real_block = block;
196 if (lo->lo_flags & LO_FLAGS_DO_BMAP) {
197 real_block = bmap(lo->lo_inode, block);
198 if (!real_block) {
199 printk("loop: block %d not present\n", block);
200 goto error_out;
201 }
202 }
203 bh = getblk(lo->lo_device, real_block, blksize);
204 if (!bh) {
205 printk("loop: device %s: getblk(-, %d, %d) returned NULL",
206 kdevname(lo->lo_device),
207 block, blksize);
208 goto error_out;
209 }
210 if (!buffer_uptodate(bh) && ((CURRENT->cmd == READ) ||
211 (offset || (len < blksize)))) {
212 ll_rw_block(READ, 1, &bh);
213 wait_on_buffer(bh);
214 if (!buffer_uptodate(bh)) {
215 brelse(bh);
216 goto error_out;
217 }
218 }
219 size = blksize - offset;
220 if (size > len)
221 size = len;
222 if ((lo->transfer)(lo, CURRENT->cmd, bh->b_data + offset,
223 dest_addr, size)) {
224 printk("loop: transfer error block %d\n", block);
225 brelse(bh);
226 goto error_out;
227 }
228 if (CURRENT->cmd == WRITE) {
229 set_bit(BH_Dirty, &bh->b_state);
230 ll_rw_block(WRITE, 1, &bh);
231 wait_on_buffer(bh);
232 if (buffer_dirty(bh)) {
233 brelse(bh);
234 goto error_out;
235 }
236 }
237 brelse(bh);
238 dest_addr += size;
239 len -= size;
240 offset = 0;
241 block++;
242 }
243 end_request(1);
244 goto repeat;
245 error_out:
246 end_request(0);
247 goto repeat;
248 }
249
250 static int loop_set_fd(struct loop_device *lo, unsigned int arg)
251 {
252 struct inode *inode;
253
254 if (arg >= NR_OPEN || !current->files->fd[arg])
255 return -EBADF;
256 if (lo->lo_inode)
257 return -EBUSY;
258 inode = current->files->fd[arg]->f_inode;
259 if (!inode) {
260 printk("loop_set_fd: NULL inode?!?\n");
261 return -EINVAL;
262 }
263 if (S_ISREG(inode->i_mode)) {
264 lo->lo_device = inode->i_dev;
265 lo->lo_flags |= LO_FLAGS_DO_BMAP;
266 } else if (S_ISBLK(inode->i_mode))
267 lo->lo_device = inode->i_rdev;
268 else
269 return -EINVAL;
270 lo->lo_inode = inode;
271 lo->lo_inode->i_count++;
272 lo->transfer = NULL;
273 figure_loop_size(lo);
274 return 0;
275 }
276
277 static int loop_clr_fd(struct loop_device *lo, kdev_t dev)
278 {
279 if (!lo->lo_inode)
280 return -ENXIO;
281 if (lo->lo_refcnt > 1)
282 return -EBUSY;
283 lo->lo_inode->i_count--;
284 lo->lo_device = 0;
285 lo->lo_inode = NULL;
286 lo->lo_encrypt_type = 0;
287 lo->lo_offset = 0;
288 lo->lo_encrypt_key_size = 0;
289 memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
290 memset(lo->lo_name, 0, LO_NAME_SIZE);
291 invalidate_buffers(dev);
292 return 0;
293 }
294
295 static int loop_set_status(struct loop_device *lo, struct loop_info *arg)
296 {
297 struct loop_info info;
298
299 if (!lo->lo_inode)
300 return -ENXIO;
301 if (!arg)
302 return -EINVAL;
303 memcpy_fromfs(&info, arg, sizeof(info));
304 if (info.lo_encrypt_key_size > LO_KEY_SIZE)
305 return -EINVAL;
306 switch (info.lo_encrypt_type) {
307 case LO_CRYPT_NONE:
308 break;
309 case LO_CRYPT_XOR:
310 if (info.lo_encrypt_key_size < 0)
311 return -EINVAL;
312 break;
313 #ifdef DES_AVAILABLE
314 case LO_CRYPT_DES:
315 if (info.lo_encrypt_key_size != 8)
316 return -EINVAL;
317 des_set_key((des_cblock *) lo->lo_encrypt_key,
318 lo->lo_des_key);
319 memcpy(lo->lo_des_init,info.lo_init,8);
320 break;
321 #endif
322 default:
323 return -EINVAL;
324 }
325 lo->lo_offset = info.lo_offset;
326 strncpy(lo->lo_name, info.lo_name, LO_NAME_SIZE);
327 lo->lo_encrypt_type = info.lo_encrypt_type;
328 lo->transfer = xfer_funcs[lo->lo_encrypt_type];
329 lo->lo_encrypt_key_size = info.lo_encrypt_key_size;
330 if (info.lo_encrypt_key_size)
331 memcpy(lo->lo_encrypt_key, info.lo_encrypt_key,
332 info.lo_encrypt_key_size);
333 figure_loop_size(lo);
334 return 0;
335 }
336
337 static int loop_get_status(struct loop_device *lo, struct loop_info *arg)
338 {
339 struct loop_info info;
340
341 if (!lo->lo_inode)
342 return -ENXIO;
343 if (!arg)
344 return -EINVAL;
345 memset(&info, 0, sizeof(info));
346 info.lo_number = lo->lo_number;
347 info.lo_device = kdev_t_to_nr(lo->lo_inode->i_dev);
348 info.lo_inode = lo->lo_inode->i_ino;
349 info.lo_rdevice = kdev_t_to_nr(lo->lo_device);
350 info.lo_offset = lo->lo_offset;
351 info.lo_flags = lo->lo_flags;
352 strncpy(info.lo_name, lo->lo_name, LO_NAME_SIZE);
353 info.lo_encrypt_type = lo->lo_encrypt_type;
354 if (lo->lo_encrypt_key_size && suser()) {
355 info.lo_encrypt_key_size = lo->lo_encrypt_key_size;
356 memcpy(info.lo_encrypt_key, lo->lo_encrypt_key,
357 lo->lo_encrypt_key_size);
358 }
359 memcpy_tofs(arg, &info, sizeof(info));
360 return 0;
361 }
362
363 static int lo_ioctl(struct inode * inode, struct file * file,
364 unsigned int cmd, unsigned long arg)
365 {
366 struct loop_device *lo;
367 int dev, err;
368
369 if (!inode)
370 return -EINVAL;
371 if (MAJOR(inode->i_rdev) != loop_major) {
372 printk("lo_ioctl: pseudo-major != %d\n", loop_major);
373 return -ENODEV;
374 }
375 dev = MINOR(inode->i_rdev);
376 if (dev >= MAX_LOOP)
377 return -ENODEV;
378 lo = &loop_dev[dev];
379 switch (cmd) {
380 case LOOP_SET_FD:
381 return loop_set_fd(lo, arg);
382 case LOOP_CLR_FD:
383 return loop_clr_fd(lo, inode->i_rdev);
384 case LOOP_SET_STATUS:
385 return loop_set_status(lo, (struct loop_info *) arg);
386 case LOOP_GET_STATUS:
387 return loop_get_status(lo, (struct loop_info *) arg);
388 case BLKGETSIZE:
389 if (!lo->lo_inode)
390 return -ENXIO;
391 if (!arg) return -EINVAL;
392 err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
393 if (err)
394 return err;
395 put_fs_long(loop_sizes[lo->lo_number] << 1, (long *) arg);
396 return 0;
397 default:
398 return -EINVAL;
399 }
400 return 0;
401 }
402
403 static int lo_open(struct inode *inode, struct file *file)
404 {
405 struct loop_device *lo;
406 int dev;
407
408 if (!inode)
409 return -EINVAL;
410 if (MAJOR(inode->i_rdev) != loop_major) {
411 printk("lo_open: pseudo-major != %d\n", loop_major);
412 return -ENODEV;
413 }
414 dev = MINOR(inode->i_rdev);
415 if (dev >= MAX_LOOP)
416 return -ENODEV;
417 lo = &loop_dev[dev];
418 lo->lo_refcnt++;
419 MOD_INC_USE_COUNT;
420 return 0;
421 }
422
423 static void lo_release(struct inode *inode, struct file *file)
424 {
425 struct loop_device *lo;
426 int dev;
427
428 if (!inode)
429 return;
430 if (MAJOR(inode->i_rdev) != loop_major) {
431 printk("lo_release: pseudo-major != %d\n", loop_major);
432 return;
433 }
434 dev = MINOR(inode->i_rdev);
435 if (dev >= MAX_LOOP)
436 return;
437 sync_dev(inode->i_rdev);
438 lo = &loop_dev[dev];
439 if (lo->lo_refcnt <= 0)
440 printk("lo_release: refcount(%d) <= 0\n", lo->lo_refcnt);
441 else {
442 lo->lo_refcnt--;
443 MOD_DEC_USE_COUNT;
444 }
445
446 return;
447 }
448
449 static struct file_operations lo_fops = {
450 NULL,
451 block_read,
452 block_write,
453 NULL,
454 NULL,
455 lo_ioctl,
456 NULL,
457 lo_open,
458 lo_release
459 };
460
461
462
463
464 #ifdef MODULE
465 #define loop_init init_module
466 #endif
467
468 int
469 loop_init( void ) {
470 int i = (loop_major ? loop_major : DEFAULT_MAJOR_NR);
471
472 if (register_blkdev(i, "loop", &lo_fops) &&
473 (i = register_blkdev(0, "loop", &lo_fops)) <= 0) {
474 printk("Unable to get major number for loop device\n");
475 return -EIO;
476 }
477 loop_major = i;
478 #ifdef MODULE
479 if (i != DEFAULT_MAJOR_NR)
480 #endif
481 printk("loop: registered device at major %d\n",loop_major);
482
483 blk_dev[loop_major].request_fn = DEVICE_REQUEST;
484 for (i=0; i < MAX_LOOP; i++) {
485 memset(&loop_dev[i], 0, sizeof(struct loop_device));
486 loop_dev[i].lo_number = i;
487 }
488 memset(&loop_sizes, 0, sizeof(loop_sizes));
489 blk_size[loop_major] = loop_sizes;
490
491 return 0;
492 }
493
494 #ifdef MODULE
495 void
496 cleanup_module( void ) {
497 if (unregister_blkdev(loop_major, "loop") != 0)
498 printk("loop: cleanup_module failed\n");
499 }
500 #endif
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