Pileus Git - ~andy/linux/blob - 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/slab.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/smp_lock.h>
  12
  13 #include "isofs.h"
  14 #include "rock.h"
  15
  16 /* These functions are designed to read the system areas of a directory record
  17  * and extract relevant information.  There are different functions provided
  18  * depending upon what information we need at the time.  One function fills
  19  * out an inode structure, a second one extracts a filename, a third one
  20  * returns a symbolic link name, and a fourth one returns the extent number
  21  * for the file. */
  22
  23 #define SIG(A,B) ((A) | ((B) << 8))     /* isonum_721() */
  24
  25 /* This is a way of ensuring that we have something in the system
  26    use fields that is compatible with Rock Ridge */
  27 #define CHECK_SP(FAIL)                          \
  28       if(rr->u.SP.magic[0] != 0xbe) FAIL;       \
  29       if(rr->u.SP.magic[1] != 0xef) FAIL;       \
  30       ISOFS_SB(inode->i_sb)->s_rock_offset=rr->u.SP.skip;
  31 /* We define a series of macros because each function must do exactly the
  32    same thing in certain places.  We use the macros to ensure that everything
  33    is done correctly */
  34
  35 #define CONTINUE_DECLS \
  36   int cont_extent = 0, cont_offset = 0, cont_size = 0;   \
  37   void *buffer = NULL
  38
  39 #define CHECK_CE                                \
  40       {cont_extent = isonum_733(rr->u.CE.extent); \
  41       cont_offset = isonum_733(rr->u.CE.offset); \
  42       cont_size = isonum_733(rr->u.CE.size);}
  43
  44 #define SETUP_ROCK_RIDGE(DE,CHR,LEN)                            \
  45   {LEN= sizeof(struct iso_directory_record) + DE->name_len[0];  \
  46   if(LEN & 1) LEN++;                                            \
  47   CHR = ((unsigned char *) DE) + LEN;                           \
  48   LEN = *((unsigned char *) DE) - LEN;                          \
  49   if (LEN<0) LEN=0;                                             \
  50   if (ISOFS_SB(inode->i_sb)->s_rock_offset!=-1)                \
  51   {                                                             \
  52      LEN-=ISOFS_SB(inode->i_sb)->s_rock_offset;                \
  53      CHR+=ISOFS_SB(inode->i_sb)->s_rock_offset;                \
  54      if (LEN<0) LEN=0;                                          \
  55   }                                                             \
  56 }
  57
  58 #define MAYBE_CONTINUE(LABEL,DEV) \
  59   {if (buffer) { kfree(buffer); buffer = NULL; } \
  60   if (cont_extent){ \
  61     int block, offset, offset1; \
  62     struct buffer_head * pbh; \
  63     buffer = kmalloc(cont_size,GFP_KERNEL); \
  64     if (!buffer) goto out; \
  65     block = cont_extent; \
  66     offset = cont_offset; \
  67     offset1 = 0; \
  68     pbh = sb_bread(DEV->i_sb, block); \
  69     if(pbh){       \
  70       if (offset > pbh->b_size || offset + cont_size > pbh->b_size){    \
  71         brelse(pbh); \
  72         goto out; \
  73       } \
  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 /* return length of name field; 0: not found, -1: to be ignored */
  87 int get_rock_ridge_filename(struct iso_directory_record *de,
  88                             char *retname, struct inode *inode)
  89 {
  90         int len;
  91         unsigned char *chr;
  92         CONTINUE_DECLS;
  93         int retnamlen = 0, truncate = 0;
  94
  95         if (!ISOFS_SB(inode->i_sb)->s_rock)
  96                 return 0;
  97         *retname = 0;
  98
  99         SETUP_ROCK_RIDGE(de, chr, len);
 100       repeat:
 101         {
 102                 struct rock_ridge *rr;
 103                 int sig;
 104
 105                 while (len > 2) {       /* There may be one byte for padding somewhere */
 106                         rr = (struct rock_ridge *)chr;
 107                         if (rr->len < 3)
 108                                 goto out;       /* Something got screwed up here */
 109                         sig = isonum_721(chr);
 110                         chr += rr->len;
 111                         len -= rr->len;
 112                         if (len < 0)
 113                                 goto out;       /* corrupted isofs */
 114
 115                         switch (sig) {
 116                         case SIG('R', 'R'):
 117                                 if ((rr->u.RR.flags[0] & RR_NM) == 0)
 118                                         goto out;
 119                                 break;
 120                         case SIG('S', 'P'):
 121                                 CHECK_SP(goto out);
 122                                 break;
 123                         case SIG('C', 'E'):
 124                                 CHECK_CE;
 125                                 break;
 126                         case SIG('N', 'M'):
 127                                 if (truncate)
 128                                         break;
 129                                 if (rr->len < 5)
 130                                         break;
 131                                 /*
 132                                  * If the flags are 2 or 4, this indicates '.' or '..'.
 133                                  * We don't want to do anything with this, because it
 134                                  * screws up the code that calls us.  We don't really
 135                                  * care anyways, since we can just use the non-RR
 136                                  * name.
 137                                  */
 138                                 if (rr->u.NM.flags & 6) {
 139                                         break;
 140                                 }
 141
 142                                 if (rr->u.NM.flags & ~1) {
 143                                         printk
 144                                             ("Unsupported NM flag settings (%d)\n",
 145                                              rr->u.NM.flags);
 146                                         break;
 147                                 }
 148                                 if ((strlen(retname) + rr->len - 5) >= 254) {
 149                                         truncate = 1;
 150                                         break;
 151                                 }
 152                                 strncat(retname, rr->u.NM.name, rr->len - 5);
 153                                 retnamlen += rr->len - 5;
 154                                 break;
 155                         case SIG('R', 'E'):
 156                                 if (buffer)
 157                                         kfree(buffer);
 158                                 return -1;
 159                         default:
 160                                 break;
 161                         }
 162                 }
 163         }
 164         MAYBE_CONTINUE(repeat, inode);
 165         if (buffer)
 166                 kfree(buffer);
 167         return retnamlen;       /* If 0, this file did not have a NM field */
 168       out:
 169         if (buffer)
 170                 kfree(buffer);
 171         return 0;
 172 }
 173
 174 static int
 175 parse_rock_ridge_inode_internal(struct iso_directory_record *de,
 176                                 struct inode *inode, int regard_xa)
 177 {
 178         int len;
 179         unsigned char *chr;
 180         int symlink_len = 0;
 181         CONTINUE_DECLS;
 182
 183         if (!ISOFS_SB(inode->i_sb)->s_rock)
 184                 return 0;
 185
 186         SETUP_ROCK_RIDGE(de, chr, len);
 187         if (regard_xa) {
 188                 chr += 14;
 189                 len -= 14;
 190                 if (len < 0)
 191                         len = 0;
 192         }
 193
 194       repeat:
 195         {
 196                 int cnt, sig;
 197                 struct inode *reloc;
 198                 struct rock_ridge *rr;
 199                 int rootflag;
 200
 201                 while (len > 2) {       /* There may be one byte for padding somewhere */
 202                         rr = (struct rock_ridge *)chr;
 203                         if (rr->len < 3)
 204                                 goto out;       /* Something got screwed up here */
 205                         sig = isonum_721(chr);
 206                         chr += rr->len;
 207                         len -= rr->len;
 208                         if (len < 0)
 209                                 goto out;       /* corrupted isofs */
 210
 211                         switch (sig) {
 212 #ifndef CONFIG_ZISOFS           /* No flag for SF or ZF */
 213                         case SIG('R', 'R'):
 214                                 if ((rr->u.RR.flags[0] &
 215                                      (RR_PX | RR_TF | RR_SL | RR_CL)) == 0)
 216                                         goto out;
 217                                 break;
 218 #endif
 219                         case SIG('S', 'P'):
 220                                 CHECK_SP(goto out);
 221                                 break;
 222                         case SIG('C', 'E'):
 223                                 CHECK_CE;
 224                                 break;
 225                         case SIG('E', 'R'):
 226                                 ISOFS_SB(inode->i_sb)->s_rock = 1;
 227                                 printk(KERN_DEBUG "ISO 9660 Extensions: ");
 228                                 {
 229                                         int p;
 230                                         for (p = 0; p < rr->u.ER.len_id; p++)
 231                                                 printk("%c", rr->u.ER.data[p]);
 232                                 }
 233                                 printk("\n");
 234                                 break;
 235                         case SIG('P', 'X'):
 236                                 inode->i_mode = isonum_733(rr->u.PX.mode);
 237                                 inode->i_nlink = isonum_733(rr->u.PX.n_links);
 238                                 inode->i_uid = isonum_733(rr->u.PX.uid);
 239                                 inode->i_gid = isonum_733(rr->u.PX.gid);
 240                                 break;
 241                         case SIG('P', 'N'):
 242                                 {
 243                                         int high, low;
 244                                         high = isonum_733(rr->u.PN.dev_high);
 245                                         low = isonum_733(rr->u.PN.dev_low);
 246                                         /*
 247                                          * The Rock Ridge standard specifies that if sizeof(dev_t) <= 4,
 248                                          * then the high field is unused, and the device number is completely
 249                                          * stored in the low field.  Some writers may ignore this subtlety,
 250                                          * and as a result we test to see if the entire device number is
 251                                          * stored in the low field, and use that.
 252                                          */
 253                                         if ((low & ~0xff) && high == 0) {
 254                                                 inode->i_rdev =
 255                                                     MKDEV(low >> 8, low & 0xff);
 256                                         } else {
 257                                                 inode->i_rdev =
 258                                                     MKDEV(high, low);
 259                                         }
 260                                 }
 261                                 break;
 262                         case SIG('T', 'F'):
 263                                 /* Some RRIP writers incorrectly place ctime in the TF_CREATE field.
 264                                    Try to handle this correctly for either case. */
 265                                 cnt = 0;        /* Rock ridge never appears on a High Sierra disk */
 266                                 if (rr->u.TF.flags & TF_CREATE) {
 267                                         inode->i_ctime.tv_sec =
 268                                             iso_date(rr->u.TF.times[cnt++].time,
 269                                                      0);
 270                                         inode->i_ctime.tv_nsec = 0;
 271                                 }
 272                                 if (rr->u.TF.flags & TF_MODIFY) {
 273                                         inode->i_mtime.tv_sec =
 274                                             iso_date(rr->u.TF.times[cnt++].time,
 275                                                      0);
 276                                         inode->i_mtime.tv_nsec = 0;
 277                                 }
 278                                 if (rr->u.TF.flags & TF_ACCESS) {
 279                                         inode->i_atime.tv_sec =
 280                                             iso_date(rr->u.TF.times[cnt++].time,
 281                                                      0);
 282                                         inode->i_atime.tv_nsec = 0;
 283                                 }
 284                                 if (rr->u.TF.flags & TF_ATTRIBUTES) {
 285                                         inode->i_ctime.tv_sec =
 286                                             iso_date(rr->u.TF.times[cnt++].time,
 287                                                      0);
 288                                         inode->i_ctime.tv_nsec = 0;
 289                                 }
 290                                 break;
 291                         case SIG('S', 'L'):
 292                                 {
 293                                         int slen;
 294                                         struct SL_component *slp;
 295                                         struct SL_component *oldslp;
 296                                         slen = rr->len - 5;
 297                                         slp = &rr->u.SL.link;
 298                                         inode->i_size = symlink_len;
 299                                         while (slen > 1) {
 300                                                 rootflag = 0;
 301                                                 switch (slp->flags & ~1) {
 302                                                 case 0:
 303                                                         inode->i_size +=
 304                                                             slp->len;
 305                                                         break;
 306                                                 case 2:
 307                                                         inode->i_size += 1;
 308                                                         break;
 309                                                 case 4:
 310                                                         inode->i_size += 2;
 311                                                         break;
 312                                                 case 8:
 313                                                         rootflag = 1;
 314                                                         inode->i_size += 1;
 315                                                         break;
 316                                                 default:
 317                                                         printk
 318                                                             ("Symlink component flag not implemented\n");
 319                                                 }
 320                                                 slen -= slp->len + 2;
 321                                                 oldslp = slp;
 322                                                 slp =
 323                                                     (struct SL_component
 324                                                      *)(((char *)slp) +
 325                                                         slp->len + 2);
 326
 327                                                 if (slen < 2) {
 328                                                         if (((rr->u.SL.
 329                                                               flags & 1) != 0)
 330                                                             &&
 331                                                             ((oldslp->
 332                                                               flags & 1) == 0))
 333                                                                 inode->i_size +=
 334                                                                     1;
 335                                                         break;
 336                                                 }
 337
 338                                                 /*
 339                                                  * If this component record isn't continued, then append a '/'.
 340                                                  */
 341                                                 if (!rootflag
 342                                                     && (oldslp->flags & 1) == 0)
 343                                                         inode->i_size += 1;
 344                                         }
 345                                 }
 346                                 symlink_len = inode->i_size;
 347                                 break;
 348                         case SIG('R', 'E'):
 349                                 printk(KERN_WARNING
 350                                        "Attempt to read inode for relocated directory\n");
 351                                 goto out;
 352                         case SIG('C', 'L'):
 353                                 ISOFS_I(inode)->i_first_extent =
 354                                     isonum_733(rr->u.CL.location);
 355                                 reloc =
 356                                     isofs_iget(inode->i_sb,
 357                                                ISOFS_I(inode)->i_first_extent,
 358                                                0);
 359                                 if (!reloc)
 360                                         goto out;
 361                                 inode->i_mode = reloc->i_mode;
 362                                 inode->i_nlink = reloc->i_nlink;
 363                                 inode->i_uid = reloc->i_uid;
 364                                 inode->i_gid = reloc->i_gid;
 365                                 inode->i_rdev = reloc->i_rdev;
 366                                 inode->i_size = reloc->i_size;
 367                                 inode->i_blocks = reloc->i_blocks;
 368                                 inode->i_atime = reloc->i_atime;
 369                                 inode->i_ctime = reloc->i_ctime;
 370                                 inode->i_mtime = reloc->i_mtime;
 371                                 iput(reloc);
 372                                 break;
 373 #ifdef CONFIG_ZISOFS
 374                         case SIG('Z', 'F'):
 375                                 if (!ISOFS_SB(inode->i_sb)->s_nocompress) {
 376                                         int algo;
 377                                         algo = isonum_721(rr->u.ZF.algorithm);
 378                                         if (algo == SIG('p', 'z')) {
 379                                                 int block_shift =
 380                                                     isonum_711(&rr->u.ZF.
 381                                                                parms[1]);
 382                                                 if (block_shift <
 383                                                     PAGE_CACHE_SHIFT
 384                                                     || block_shift > 17) {
 385                                                         printk(KERN_WARNING
 386                                                                "isofs: Can't handle ZF block size of 2^%d\n",
 387                                                                block_shift);
 388                                                 } else {
 389                                                         /* Note: we don't change i_blocks here */
 390                                                         ISOFS_I(inode)->
 391                                                             i_file_format =
 392                                                             isofs_file_compressed;
 393                                                         /* Parameters to compression algorithm (header size, block size) */
 394                                                         ISOFS_I(inode)->
 395                                                             i_format_parm[0] =
 396                                                             isonum_711(&rr->u.
 397                                                                        ZF.
 398                                                                        parms
 399                                                                        [0]);
 400                                                         ISOFS_I(inode)->
 401                                                             i_format_parm[1] =
 402                                                             isonum_711(&rr->u.
 403                                                                        ZF.
 404                                                                        parms
 405                                                                        [1]);
 406                                                         inode->i_size =
 407                                                             isonum_733(rr->u.ZF.
 408                                                                        real_size);
 409                                                 }
 410                                         } else {
 411                                                 printk(KERN_WARNING
 412                                                        "isofs: Unknown ZF compression algorithm: %c%c\n",
 413                                                        rr->u.ZF.algorithm[0],
 414                                                        rr->u.ZF.algorithm[1]);
 415                                         }
 416                                 }
 417                                 break;
 418 #endif
 419                         default:
 420                                 break;
 421                         }
 422                 }
 423         }
 424         MAYBE_CONTINUE(repeat, inode);
 425       out:
 426         if (buffer)
 427                 kfree(buffer);
 428         return 0;
 429 }
 430
 431 static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
 432 {
 433         int slen;
 434         int rootflag;
 435         struct SL_component *oldslp;
 436         struct SL_component *slp;
 437         slen = rr->len - 5;
 438         slp = &rr->u.SL.link;
 439         while (slen > 1) {
 440                 rootflag = 0;
 441                 switch (slp->flags & ~1) {
 442                 case 0:
 443                         if (slp->len > plimit - rpnt)
 444                                 return NULL;
 445                         memcpy(rpnt, slp->text, slp->len);
 446                         rpnt += slp->len;
 447                         break;
 448                 case 2:
 449                         if (rpnt >= plimit)
 450                                 return NULL;
 451                         *rpnt++ = '.';
 452                         break;
 453                 case 4:
 454                         if (2 > plimit - rpnt)
 455                                 return NULL;
 456                         *rpnt++ = '.';
 457                         *rpnt++ = '.';
 458                         break;
 459                 case 8:
 460                         if (rpnt >= plimit)
 461                                 return NULL;
 462                         rootflag = 1;
 463                         *rpnt++ = '/';
 464                         break;
 465                 default:
 466                         printk("Symlink component flag not implemented (%d)\n",
 467                                slp->flags);
 468                 }
 469                 slen -= slp->len + 2;
 470                 oldslp = slp;
 471                 slp = (struct SL_component *)((char *)slp + slp->len + 2);
 472
 473                 if (slen < 2) {
 474                         /*
 475                          * If there is another SL record, and this component
 476                          * record isn't continued, then add a slash.
 477                          */
 478                         if ((!rootflag) && (rr->u.SL.flags & 1) &&
 479                             !(oldslp->flags & 1)) {
 480                                 if (rpnt >= plimit)
 481                                         return NULL;
 482                                 *rpnt++ = '/';
 483                         }
 484                         break;
 485                 }
 486
 487                 /*
 488                  * If this component record isn't continued, then append a '/'.
 489                  */
 490                 if (!rootflag && !(oldslp->flags & 1)) {
 491                         if (rpnt >= plimit)
 492                                 return NULL;
 493                         *rpnt++ = '/';
 494                 }
 495         }
 496         return rpnt;
 497 }
 498
 499 int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
 500 {
 501         int result = parse_rock_ridge_inode_internal(de, inode, 0);
 502         /* if rockridge flag was reset and we didn't look for attributes
 503          * behind eventual XA attributes, have a look there */
 504         if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
 505             && (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
 506                 result = parse_rock_ridge_inode_internal(de, inode, 14);
 507         }
 508         return result;
 509 }
 510
 511 /* readpage() for symlinks: reads symlink contents into the page and either
 512    makes it uptodate and returns 0 or returns error (-EIO) */
 513
 514 static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 515 {
 516         struct inode *inode = page->mapping->host;
 517         struct iso_inode_info *ei = ISOFS_I(inode);
 518         char *link = kmap(page);
 519         unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 520         struct buffer_head *bh;
 521         char *rpnt = link;
 522         unsigned char *pnt;
 523         struct iso_directory_record *raw_inode;
 524         CONTINUE_DECLS;
 525         unsigned long block, offset;
 526         int sig;
 527         int len;
 528         unsigned char *chr;
 529         struct rock_ridge *rr;
 530
 531         if (!ISOFS_SB(inode->i_sb)->s_rock)
 532                 goto error;
 533
 534         block = ei->i_iget5_block;
 535         lock_kernel();
 536         bh = sb_bread(inode->i_sb, block);
 537         if (!bh)
 538                 goto out_noread;
 539
 540         offset = ei->i_iget5_offset;
 541         pnt = (unsigned char *)bh->b_data + offset;
 542
 543         raw_inode = (struct iso_directory_record *)pnt;
 544
 545         /*
 546          * If we go past the end of the buffer, there is some sort of error.
 547          */
 548         if (offset + *pnt > bufsize)
 549                 goto out_bad_span;
 550
 551         /* Now test for possible Rock Ridge extensions which will override
 552            some of these numbers in the inode structure. */
 553
 554         SETUP_ROCK_RIDGE(raw_inode, chr, len);
 555
 556       repeat:
 557         while (len > 2) {       /* There may be one byte for padding somewhere */
 558                 rr = (struct rock_ridge *)chr;
 559                 if (rr->len < 3)
 560                         goto out;       /* Something got screwed up here */
 561                 sig = isonum_721(chr);
 562                 chr += rr->len;
 563                 len -= rr->len;
 564                 if (len < 0)
 565                         goto out;       /* corrupted isofs */
 566
 567                 switch (sig) {
 568                 case SIG('R', 'R'):
 569                         if ((rr->u.RR.flags[0] & RR_SL) == 0)
 570                                 goto out;
 571                         break;
 572                 case SIG('S', 'P'):
 573                         CHECK_SP(goto out);
 574                         break;
 575                 case SIG('S', 'L'):
 576                         rpnt = get_symlink_chunk(rpnt, rr,
 577                                                  link + (PAGE_SIZE - 1));
 578                         if (rpnt == NULL)
 579                                 goto out;
 580                         break;
 581                 case SIG('C', 'E'):
 582                         /* This tells is if there is a continuation record */
 583                         CHECK_CE;
 584                 default:
 585                         break;
 586                 }
 587         }
 588         MAYBE_CONTINUE(repeat, inode);
 589         if (buffer)
 590                 kfree(buffer);
 591
 592         if (rpnt == link)
 593                 goto fail;
 594         brelse(bh);
 595         *rpnt = '\0';
 596         unlock_kernel();
 597         SetPageUptodate(page);
 598         kunmap(page);
 599         unlock_page(page);
 600         return 0;
 601
 602         /* error exit from macro */
 603       out:
 604         if (buffer)
 605                 kfree(buffer);
 606         goto fail;
 607       out_noread:
 608         printk("unable to read i-node block");
 609         goto fail;
 610       out_bad_span:
 611         printk("symlink spans iso9660 blocks\n");
 612       fail:
 613         brelse(bh);
 614         unlock_kernel();
 615       error:
 616         SetPageError(page);
 617         kunmap(page);
 618         unlock_page(page);
 619         return -EIO;
 620 }
 621
 622 struct address_space_operations isofs_symlink_aops = {
 623         .readpage = rock_ridge_symlink_readpage
 624 };