File: /usr/src/linux/fs/isofs/rock.c
1 /*
2 * linux/fs/isofs/rock.c
3 *
4 * (C) 1992, 1993 Eric Youngdale
5 *
6 * Rock Ridge Extensions to iso9660
7 */
8
9 #include <linux/stat.h>
10 #include <linux/sched.h>
11 #include <linux/iso_fs.h>
12 #include <linux/string.h>
13 #include <linux/mm.h>
14 #include <linux/slab.h>
15 #include <linux/pagemap.h>
16 #include <linux/smp_lock.h>
17
18 #include "rock.h"
19
20 /* These functions are designed to read the system areas of a directory record
21 * and extract relevant information. There are different functions provided
22 * depending upon what information we need at the time. One function fills
23 * out an inode structure, a second one extracts a filename, a third one
24 * returns a symbolic link name, and a fourth one returns the extent number
25 * for the file. */
26
27 #define SIG(A,B) ((A << 8) | B)
28
29
30 /* This is a way of ensuring that we have something in the system
31 use fields that is compatible with Rock Ridge */
32 #define CHECK_SP(FAIL) \
33 if(rr->u.SP.magic[0] != 0xbe) FAIL; \
34 if(rr->u.SP.magic[1] != 0xef) FAIL; \
35 inode->i_sb->u.isofs_sb.s_rock_offset=rr->u.SP.skip;
36 /* We define a series of macros because each function must do exactly the
37 same thing in certain places. We use the macros to ensure that everything
38 is done correctly */
39
40 #define CONTINUE_DECLS \
41 int cont_extent = 0, cont_offset = 0, cont_size = 0; \
42 void * buffer = 0
43
44 #define CHECK_CE \
45 {cont_extent = isonum_733(rr->u.CE.extent); \
46 cont_offset = isonum_733(rr->u.CE.offset); \
47 cont_size = isonum_733(rr->u.CE.size);}
48
49 #define SETUP_ROCK_RIDGE(DE,CHR,LEN) \
50 {LEN= sizeof(struct iso_directory_record) + DE->name_len[0]; \
51 if(LEN & 1) LEN++; \
52 CHR = ((unsigned char *) DE) + LEN; \
53 LEN = *((unsigned char *) DE) - LEN; \
54 if (inode->i_sb->u.isofs_sb.s_rock_offset!=-1) \
55 { \
56 LEN-=inode->i_sb->u.isofs_sb.s_rock_offset; \
57 CHR+=inode->i_sb->u.isofs_sb.s_rock_offset; \
58 if (LEN<0) LEN=0; \
59 } \
60 }
61
62 #define MAYBE_CONTINUE(LABEL,DEV) \
63 {if (buffer) kfree(buffer); \
64 if (cont_extent){ \
65 int block, offset, offset1; \
66 struct buffer_head * pbh; \
67 buffer = kmalloc(cont_size,GFP_KERNEL); \
68 if (!buffer) goto out; \
69 block = cont_extent; \
70 offset = cont_offset; \
71 offset1 = 0; \
72 pbh = bread(DEV->i_dev, block, ISOFS_BUFFER_SIZE(DEV)); \
73 if(pbh){ \
74 memcpy(buffer + offset1, pbh->b_data + offset, cont_size - offset1); \
75 brelse(pbh); \
76 chr = (unsigned char *) buffer; \
77 len = cont_size; \
78 cont_extent = 0; \
79 cont_size = 0; \
80 cont_offset = 0; \
81 goto LABEL; \
82 } \
83 printk("Unable to read rock-ridge attributes\n"); \
84 }}
85
86 /* This is the inner layer of the get filename routine, and is called
87 for each system area and continuation record related to the file */
88
89 int find_rock_ridge_relocation(struct iso_directory_record * de,
90 struct inode * inode) {
91 int flag;
92 int len;
93 int retval;
94 unsigned char * chr;
95 CONTINUE_DECLS;
96 flag = 0;
97
98 /* If this is a '..' then we are looking for the parent, otherwise we
99 are looking for the child */
100
101 if (de->name[0]==1 && de->name_len[0]==1) flag = 1;
102 /* Return value if we do not find appropriate record. */
103 retval = isonum_733 (de->extent);
104
105 if (!inode->i_sb->u.isofs_sb.s_rock) return retval;
106
107 SETUP_ROCK_RIDGE(de, chr, len);
108 repeat:
109 {
110 int rrflag, sig;
111 struct rock_ridge * rr;
112
113 while (len > 1){ /* There may be one byte for padding somewhere */
114 rr = (struct rock_ridge *) chr;
115 if (rr->len == 0) goto out; /* Something got screwed up here */
116 sig = (chr[0] << 8) + chr[1];
117 chr += rr->len;
118 len -= rr->len;
119
120 switch(sig){
121 case SIG('R','R'):
122 rrflag = rr->u.RR.flags[0];
123 if (flag && !(rrflag & RR_PL)) goto out;
124 if (!flag && !(rrflag & RR_CL)) goto out;
125 break;
126 case SIG('S','P'):
127 CHECK_SP(goto out);
128 break;
129 case SIG('C','L'):
130 if (flag == 0) {
131 retval = isonum_733(rr->u.CL.location);
132 goto out;
133 }
134 break;
135 case SIG('P','L'):
136 if (flag != 0) {
137 retval = isonum_733(rr->u.PL.location);
138 goto out;
139 }
140 break;
141 case SIG('C','E'):
142 CHECK_CE; /* This tells is if there is a continuation record */
143 break;
144 default:
145 break;
146 }
147 }
148 }
149 MAYBE_CONTINUE(repeat, inode);
150 return retval;
151 out:
152 if(buffer) kfree(buffer);
153 return retval;
154 }
155
156 /* return length of name field; 0: not found, -1: to be ignored */
157 int get_rock_ridge_filename(struct iso_directory_record * de,
158 char * retname, struct inode * inode)
159 {
160 int len;
161 unsigned char * chr;
162 CONTINUE_DECLS;
163 int retnamlen = 0, truncate=0;
164
165 if (!inode->i_sb->u.isofs_sb.s_rock) return 0;
166 *retname = 0;
167
168 SETUP_ROCK_RIDGE(de, chr, len);
169 repeat:
170 {
171 struct rock_ridge * rr;
172 int sig;
173
174 while (len > 1){ /* There may be one byte for padding somewhere */
175 rr = (struct rock_ridge *) chr;
176 if (rr->len == 0) goto out; /* Something got screwed up here */
177 sig = (chr[0] << 8) + chr[1];
178 chr += rr->len;
179 len -= rr->len;
180
181 switch(sig){
182 case SIG('R','R'):
183 if((rr->u.RR.flags[0] & RR_NM) == 0) goto out;
184 break;
185 case SIG('S','P'):
186 CHECK_SP(goto out);
187 break;
188 case SIG('C','E'):
189 CHECK_CE;
190 break;
191 case SIG('N','M'):
192 if (truncate) break;
193 /*
194 * If the flags are 2 or 4, this indicates '.' or '..'.
195 * We don't want to do anything with this, because it
196 * screws up the code that calls us. We don't really
197 * care anyways, since we can just use the non-RR
198 * name.
199 */
200 if (rr->u.NM.flags & 6) {
201 break;
202 }
203
204 if (rr->u.NM.flags & ~1) {
205 printk("Unsupported NM flag settings (%d)\n",rr->u.NM.flags);
206 break;
207 }
208 if((strlen(retname) + rr->len - 5) >= 254) {
209 truncate = 1;
210 break;
211 }
212 strncat(retname, rr->u.NM.name, rr->len - 5);
213 retnamlen += rr->len - 5;
214 break;
215 case SIG('R','E'):
216 if (buffer) kfree(buffer);
217 return -1;
218 default:
219 break;
220 }
221 }
222 }
223 MAYBE_CONTINUE(repeat,inode);
224 return retnamlen; /* If 0, this file did not have a NM field */
225 out:
226 if(buffer) kfree(buffer);
227 return 0;
228 }
229
230 int parse_rock_ridge_inode_internal(struct iso_directory_record * de,
231 struct inode * inode,int regard_xa){
232 int len;
233 unsigned char * chr;
234 int symlink_len = 0;
235 CONTINUE_DECLS;
236
237 if (!inode->i_sb->u.isofs_sb.s_rock) return 0;
238
239 SETUP_ROCK_RIDGE(de, chr, len);
240 if (regard_xa)
241 {
242 chr+=14;
243 len-=14;
244 if (len<0) len=0;
245 };
246
247 repeat:
248 {
249 int cnt, sig;
250 struct inode * reloc;
251 struct rock_ridge * rr;
252 int rootflag;
253
254 while (len > 1){ /* There may be one byte for padding somewhere */
255 rr = (struct rock_ridge *) chr;
256 if (rr->len == 0) goto out; /* Something got screwed up here */
257 sig = (chr[0] << 8) + chr[1];
258 chr += rr->len;
259 len -= rr->len;
260
261 switch(sig){
262 case SIG('R','R'):
263 if((rr->u.RR.flags[0] &
264 (RR_PX | RR_TF | RR_SL | RR_CL)) == 0) goto out;
265 break;
266 case SIG('S','P'):
267 CHECK_SP(goto out);
268 break;
269 case SIG('C','E'):
270 CHECK_CE;
271 break;
272 case SIG('E','R'):
273 inode->i_sb->u.isofs_sb.s_rock = 1;
274 printk(KERN_DEBUG "ISO 9660 Extensions: ");
275 { int p;
276 for(p=0;p<rr->u.ER.len_id;p++) printk("%c",rr->u.ER.data[p]);
277 }
278 printk("\n");
279 break;
280 case SIG('P','X'):
281 inode->i_mode = isonum_733(rr->u.PX.mode);
282 inode->i_nlink = isonum_733(rr->u.PX.n_links);
283 inode->i_uid = isonum_733(rr->u.PX.uid);
284 inode->i_gid = isonum_733(rr->u.PX.gid);
285 break;
286 case SIG('P','N'):
287 { int high, low;
288 high = isonum_733(rr->u.PN.dev_high);
289 low = isonum_733(rr->u.PN.dev_low);
290 /*
291 * The Rock Ridge standard specifies that if sizeof(dev_t) <= 4,
292 * then the high field is unused, and the device number is completely
293 * stored in the low field. Some writers may ignore this subtlety,
294 * and as a result we test to see if the entire device number is
295 * stored in the low field, and use that.
296 */
297 if((low & ~0xff) && high == 0) {
298 inode->i_rdev = MKDEV(low >> 8, low & 0xff);
299 } else {
300 inode->i_rdev = MKDEV(high, low);
301 }
302 }
303 break;
304 case SIG('T','F'):
305 /* Some RRIP writers incorrectly place ctime in the TF_CREATE field.
306 Try to handle this correctly for either case. */
307 cnt = 0; /* Rock ridge never appears on a High Sierra disk */
308 if(rr->u.TF.flags & TF_CREATE)
309 inode->i_ctime = iso_date(rr->u.TF.times[cnt++].time, 0);
310 if(rr->u.TF.flags & TF_MODIFY)
311 inode->i_mtime = iso_date(rr->u.TF.times[cnt++].time, 0);
312 if(rr->u.TF.flags & TF_ACCESS)
313 inode->i_atime = iso_date(rr->u.TF.times[cnt++].time, 0);
314 if(rr->u.TF.flags & TF_ATTRIBUTES)
315 inode->i_ctime = iso_date(rr->u.TF.times[cnt++].time, 0);
316 break;
317 case SIG('S','L'):
318 {int slen;
319 struct SL_component * slp;
320 struct SL_component * oldslp;
321 slen = rr->len - 5;
322 slp = &rr->u.SL.link;
323 inode->i_size = symlink_len;
324 while (slen > 1){
325 rootflag = 0;
326 switch(slp->flags &~1){
327 case 0:
328 inode->i_size += slp->len;
329 break;
330 case 2:
331 inode->i_size += 1;
332 break;
333 case 4:
334 inode->i_size += 2;
335 break;
336 case 8:
337 rootflag = 1;
338 inode->i_size += 1;
339 break;
340 default:
341 printk("Symlink component flag not implemented\n");
342 }
343 slen -= slp->len + 2;
344 oldslp = slp;
345 slp = (struct SL_component *) (((char *) slp) + slp->len + 2);
346
347 if(slen < 2) {
348 if( ((rr->u.SL.flags & 1) != 0)
349 && ((oldslp->flags & 1) == 0) ) inode->i_size += 1;
350 break;
351 }
352
353 /*
354 * If this component record isn't continued, then append a '/'.
355 */
356 if (!rootflag && (oldslp->flags & 1) == 0)
357 inode->i_size += 1;
358 }
359 }
360 symlink_len = inode->i_size;
361 break;
362 case SIG('R','E'):
363 printk(KERN_WARNING "Attempt to read inode for relocated directory\n");
364 goto out;
365 case SIG('C','L'):
366 inode->u.isofs_i.i_first_extent = isonum_733(rr->u.CL.location);
367 reloc = iget(inode->i_sb,
368 (inode->u.isofs_i.i_first_extent <<
369 inode -> i_sb -> u.isofs_sb.s_log_zone_size));
370 if (!reloc)
371 goto out;
372 inode->i_mode = reloc->i_mode;
373 inode->i_nlink = reloc->i_nlink;
374 inode->i_uid = reloc->i_uid;
375 inode->i_gid = reloc->i_gid;
376 inode->i_rdev = reloc->i_rdev;
377 inode->i_size = reloc->i_size;
378 inode->i_atime = reloc->i_atime;
379 inode->i_ctime = reloc->i_ctime;
380 inode->i_mtime = reloc->i_mtime;
381 iput(reloc);
382 break;
383 default:
384 break;
385 }
386 }
387 }
388 MAYBE_CONTINUE(repeat,inode);
389 return 0;
390 out:
391 if(buffer) kfree(buffer);
392 return 0;
393 }
394
395 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr)
396 {
397 int slen;
398 int rootflag;
399 struct SL_component *oldslp;
400 struct SL_component *slp;
401 slen = rr->len - 5;
402 slp = &rr->u.SL.link;
403 while (slen > 1) {
404 rootflag = 0;
405 switch (slp->flags & ~1) {
406 case 0:
407 memcpy(rpnt, slp->text, slp->len);
408 rpnt+=slp->len;
409 break;
410 case 4:
411 *rpnt++='.';
412 /* fallthru */
413 case 2:
414 *rpnt++='.';
415 break;
416 case 8:
417 rootflag = 1;
418 *rpnt++='/';
419 break;
420 default:
421 printk("Symlink component flag not implemented (%d)\n",
422 slp->flags);
423 }
424 slen -= slp->len + 2;
425 oldslp = slp;
426 slp = (struct SL_component *) ((char *) slp + slp->len + 2);
427
428 if (slen < 2) {
429 /*
430 * If there is another SL record, and this component
431 * record isn't continued, then add a slash.
432 */
433 if ((!rootflag) && (rr->u.SL.flags & 1) && !(oldslp->flags & 1))
434 *rpnt++='/';
435 break;
436 }
437
438 /*
439 * If this component record isn't continued, then append a '/'.
440 */
441 if (!rootflag && !(oldslp->flags & 1))
442 *rpnt++='/';
443
444 }
445 return rpnt;
446 }
447
448 int parse_rock_ridge_inode(struct iso_directory_record * de,
449 struct inode * inode)
450 {
451 int result=parse_rock_ridge_inode_internal(de,inode,0);
452 /* if rockridge flag was reset and we didn't look for attributes
453 * behind eventual XA attributes, have a look there */
454 if ((inode->i_sb->u.isofs_sb.s_rock_offset==-1)
455 &&(inode->i_sb->u.isofs_sb.s_rock==2))
456 {
457 result=parse_rock_ridge_inode_internal(de,inode,14);
458 };
459 return result;
460 };
461
462 /* readpage() for symlinks: reads symlink contents into the page and either
463 makes it uptodate and returns 0 or returns error (-EIO) */
464
465 static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
466 {
467 struct inode *inode = page->mapping->host;
468 char *link = kmap(page);
469 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
470 unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
471 struct buffer_head *bh;
472 char *rpnt = link;
473 unsigned char *pnt;
474 struct iso_directory_record *raw_inode;
475 CONTINUE_DECLS;
476 int block;
477 int sig;
478 int len;
479 unsigned char *chr;
480 struct rock_ridge *rr;
481
482 if (!inode->i_sb->u.isofs_sb.s_rock)
483 panic ("Cannot have symlink with high sierra variant of iso filesystem\n");
484
485 block = inode->i_ino >> bufbits;
486 lock_kernel();
487 bh = bread(inode->i_dev, block, bufsize);
488 if (!bh)
489 goto out_noread;
490
491 pnt = (unsigned char *) bh->b_data + (inode->i_ino & (bufsize - 1));
492
493 raw_inode = (struct iso_directory_record *) pnt;
494
495 /*
496 * If we go past the end of the buffer, there is some sort of error.
497 */
498 if ((inode->i_ino & (bufsize - 1)) + *pnt > bufsize)
499 goto out_bad_span;
500
501 /* Now test for possible Rock Ridge extensions which will override
502 some of these numbers in the inode structure. */
503
504 SETUP_ROCK_RIDGE(raw_inode, chr, len);
505
506 repeat:
507 while (len > 1) { /* There may be one byte for padding somewhere */
508 rr = (struct rock_ridge *) chr;
509 if (rr->len == 0)
510 goto out; /* Something got screwed up here */
511 sig = (chr[0] << 8) + chr[1];
512 chr += rr->len;
513 len -= rr->len;
514
515 switch (sig) {
516 case SIG('R', 'R'):
517 if ((rr->u.RR.flags[0] & RR_SL) == 0)
518 goto out;
519 break;
520 case SIG('S', 'P'):
521 CHECK_SP(goto out);
522 break;
523 case SIG('S', 'L'):
524 rpnt = get_symlink_chunk(rpnt, rr);
525 break;
526 case SIG('C', 'E'):
527 /* This tells is if there is a continuation record */
528 CHECK_CE;
529 default:
530 break;
531 }
532 }
533 MAYBE_CONTINUE(repeat, inode);
534
535 if (rpnt == link)
536 goto fail;
537 brelse(bh);
538 *rpnt = '\0';
539 unlock_kernel();
540 SetPageUptodate(page);
541 kunmap(page);
542 UnlockPage(page);
543 return 0;
544
545 /* error exit from macro */
546 out:
547 if (buffer)
548 kfree(buffer);
549 goto fail;
550 out_noread:
551 printk("unable to read i-node block");
552 goto fail;
553 out_bad_span:
554 printk("symlink spans iso9660 blocks\n");
555 fail:
556 brelse(bh);
557 unlock_kernel();
558 SetPageError(page);
559 kunmap(page);
560 UnlockPage(page);
561 return -EIO;
562 }
563
564 struct address_space_operations isofs_symlink_aops = {
565 readpage: rock_ridge_symlink_readpage
566 };
567