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