lib/libstand/cd9660.c

   1 /*
   2  * Copyright (C) 1996 Wolfgang Solfrank.
   3  * Copyright (C) 1996 TooLs GmbH.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by TooLs GmbH.
  17  * 4. The name of TooLs GmbH may not be used to endorse or promote products
  18  *    derived from this software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
  21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  26  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  28  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  29  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  *
  31  * $NetBSD: cd9660.c,v 1.5 1997/06/26 19:11:33 drochner Exp $
  32  * $FreeBSD: src/lib/libstand/cd9660.c,v 1.4.2.4 2001/12/21 22:17:44 jhb Exp $
  33  * $DragonFly: src/lib/libstand/cd9660.c,v 1.6 2005/12/11 02:27:26 swildner Exp $
  34  */
  35
  36 /*
  37  * Stand-alone ISO9660 file reading package.
  38  *
  39  * Note: This doesn't support Rock Ridge extensions, extended attributes,
  40  * blocksizes other than 2048 bytes, multi-extent files, etc.
  41  */
  42 #include <sys/param.h>
  43 #include <string.h>
  44 #include <sys/dirent.h>
  45 #include <isofs/cd9660/iso.h>
  46 #include <isofs/cd9660/cd9660_rrip.h>
  47
  48 #include "stand.h"
  49
  50 #define SUSP_CONTINUATION       "CE"
  51 #define SUSP_PRESENT            "SP"
  52 #define SUSP_STOP               "ST"
  53 #define SUSP_EXTREF             "ER"
  54 #define RRIP_NAME               "NM"
  55
  56 typedef struct {
  57         ISO_SUSP_HEADER         h;
  58         u_char signature        [ISODCL (  5,    6)];
  59         u_char len_skp          [ISODCL (  7,    7)]; /* 711 */
  60 } ISO_SUSP_PRESENT;
  61
  62 static int      buf_read_file(struct open_file *f, char **buf_p,
  63                     size_t *size_p);
  64 static int      cd9660_open(const char *path, struct open_file *f);
  65 static int      cd9660_close(struct open_file *f);
  66 static int      cd9660_read(struct open_file *f, void *buf, size_t size,
  67                     size_t *resid);
  68 static int      cd9660_write(struct open_file *f, void *buf, size_t size,
  69                     size_t *resid);
  70 static off_t    cd9660_seek(struct open_file *f, off_t offset, int where);
  71 static int      cd9660_stat(struct open_file *f, struct stat *sb);
  72 static int      cd9660_readdir(struct open_file *f, struct dirent *d);
  73 static int      dirmatch(struct open_file *f, const char *path,
  74                     struct iso_directory_record *dp, int use_rrip, int lenskip);
  75 static int      rrip_check(struct open_file *f, struct iso_directory_record *dp,
  76                     int *lenskip);
  77 static char     *rrip_lookup_name(struct open_file *f,
  78                     struct iso_directory_record *dp, int lenskip, size_t *len);
  79 static ISO_SUSP_HEADER *susp_lookup_record(struct open_file *f,
  80                     const char *identifier, struct iso_directory_record *dp,
  81                     int lenskip);
  82
  83 struct fs_ops cd9660_fsops = {
  84         "cd9660",
  85         cd9660_open,
  86         cd9660_close,
  87         cd9660_read,
  88         cd9660_write,
  89         cd9660_seek,
  90         cd9660_stat,
  91         cd9660_readdir
  92 };
  93
  94 #define F_ISDIR         0x0001          /* Directory */
  95 #define F_ROOTDIR       0x0002          /* Root directory */
  96 #define F_RR            0x0004          /* Rock Ridge on this volume */
  97
  98 struct file {
  99         int             f_flags;        /* file flags */
 100         off_t           f_off;          /* Current offset within file */
 101         daddr_t         f_bno;          /* Starting block number */
 102         off_t           f_size;         /* Size of file */
 103         daddr_t         f_buf_blkno;    /* block number of data block */
 104         char            *f_buf;         /* buffer for data block */
 105         int             f_susp_skip;    /* len_skip for SUSP records */
 106 };
 107
 108 struct ptable_ent {
 109         char namlen     [ISODCL( 1, 1)];        /* 711 */
 110         char extlen     [ISODCL( 2, 2)];        /* 711 */
 111         char block      [ISODCL( 3, 6)];        /* 732 */
 112         char parent     [ISODCL( 7, 8)];        /* 722 */
 113         char name       [1];
 114 };
 115 #define PTFIXSZ         8
 116 #define PTSIZE(pp)      roundup(PTFIXSZ + isonum_711((pp)->namlen), 2)
 117
 118 #define cdb2devb(bno)   ((bno) * ISO_DEFAULT_BLOCK_SIZE / DEV_BSIZE)
 119
 120 /* XXX these should be in the system headers */
 121 static __inline int
 122 isonum_722(u_char *p)
 123 {
 124         return (*p << 8)|p[1];
 125 }
 126
 127 static __inline int
 128 isonum_732(u_char *p)
 129 {
 130         return (*p << 24)|(p[1] << 16)|(p[2] << 8)|p[3];
 131 }
 132
 133 static ISO_SUSP_HEADER *
 134 susp_lookup_record(struct open_file *f, const char *identifier,
 135     struct iso_directory_record *dp, int lenskip)
 136 {
 137         static char susp_buffer[ISO_DEFAULT_BLOCK_SIZE];
 138         ISO_SUSP_HEADER *sh;
 139         ISO_RRIP_CONT *shc;
 140         char *p, *end;
 141         int error;
 142         size_t read;
 143
 144         p = dp->name + isonum_711(dp->name_len) + lenskip;
 145         /* Names of even length have a padding byte after the name. */
 146         if ((isonum_711(dp->name_len) & 1) == 0)
 147                 p++;
 148         end = (char *)dp + isonum_711(dp->length);
 149         while (p + 3 < end) {
 150                 sh = (ISO_SUSP_HEADER *)p;
 151                 if (bcmp(sh->type, identifier, 2) == 0)
 152                         return (sh);
 153                 if (bcmp(sh->type, SUSP_STOP, 2) == 0)
 154                         return (NULL);
 155                 if (bcmp(sh->type, SUSP_CONTINUATION, 2) == 0) {
 156                         shc = (ISO_RRIP_CONT *)sh;
 157                         error = f->f_dev->dv_strategy(f->f_devdata, F_READ,
 158                             cdb2devb(isonum_733(shc->location)),
 159                             ISO_DEFAULT_BLOCK_SIZE, susp_buffer, &read);
 160
 161                         /* Bail if it fails. */
 162                         if (error != 0 || read != ISO_DEFAULT_BLOCK_SIZE)
 163                                 return (NULL);
 164                         p = susp_buffer + isonum_733(shc->offset);
 165                         end = p + isonum_733(shc->length);
 166                 } else
 167                         /* Ignore this record and skip to the next. */
 168                         p += isonum_711(sh->length);
 169         }
 170         return (NULL);
 171 }
 172
 173 static char *
 174 rrip_lookup_name(struct open_file *f, struct iso_directory_record *dp,
 175     int lenskip, size_t *len)
 176 {
 177         ISO_RRIP_ALTNAME *p;
 178
 179         if (len == NULL)
 180                 return (NULL);
 181
 182         p = (ISO_RRIP_ALTNAME *)susp_lookup_record(f, RRIP_NAME, dp, lenskip);
 183         if (p == NULL)
 184                 return (NULL);
 185         switch (*p->flags) {
 186         case ISO_SUSP_CFLAG_CURRENT:
 187                 *len = 1;
 188                 return (".");
 189         case ISO_SUSP_CFLAG_PARENT:
 190                 *len = 2;
 191                 return ("..");
 192         case 0:
 193                 *len = isonum_711(p->h.length) - 5;
 194                 return ((char *)p + 5);
 195         default:
 196                 /*
 197                  * We don't handle hostnames or continued names as they are
 198                  * too hard, so just bail and use the default name.
 199                  */
 200                 return (NULL);
 201         }
 202 }
 203
 204 static int
 205 rrip_check(struct open_file *f, struct iso_directory_record *dp, int *lenskip)
 206 {
 207         ISO_SUSP_PRESENT *sp;
 208         ISO_RRIP_EXTREF *er;
 209         char *p;
 210
 211         /* First, see if we can find a SP field. */
 212         p = dp->name + isonum_711(dp->name_len);
 213         if (p > (char *)dp + isonum_711(dp->length))
 214                 return (0);
 215         sp = (ISO_SUSP_PRESENT *)p;
 216         if (bcmp(sp->h.type, SUSP_PRESENT, 2) != 0)
 217                 return (0);
 218         if (isonum_711(sp->h.length) != sizeof(ISO_SUSP_PRESENT))
 219                 return (0);
 220         if (sp->signature[0] != 0xbe || sp->signature[1] != 0xef)
 221                 return (0);
 222         *lenskip = isonum_711(sp->len_skp);
 223
 224         /*
 225          * Now look for an ER field.  If RRIP is present, then there must
 226          * be at least one of these.  It would be more pedantic to walk
 227          * through the list of fields looking for a Rock Ridge ER field.
 228          */
 229         er = (ISO_RRIP_EXTREF *)susp_lookup_record(f, SUSP_EXTREF, dp, 0);
 230         if (er == NULL)
 231                 return (0);
 232         return (1);
 233 }
 234
 235 static int
 236 dirmatch(struct open_file *f, const char *path, struct iso_directory_record *dp,
 237     int use_rrip, int lenskip)
 238 {
 239         size_t len;
 240         char *cp;
 241         int i, icase;
 242
 243         if (use_rrip)
 244                 cp = rrip_lookup_name(f, dp, lenskip, &len);
 245         else
 246                 cp = NULL;
 247         if (cp == NULL) {
 248                 len = isonum_711(dp->name_len);
 249                 cp = dp->name;
 250                 icase = 1;
 251         } else
 252                 icase = 0;
 253         for (i = len; --i >= 0; path++, cp++) {
 254                 if (!*path || *path == '/')
 255                         break;
 256                 if (*path == *cp)
 257                         continue;
 258                 if (!icase && toupper(*path) == *cp)
 259                         continue;
 260                 return 0;
 261         }
 262         if (*path && *path != '/')
 263                 return 0;
 264         /*
 265          * Allow stripping of trailing dots and the version number.
 266          * Note that this will find the first instead of the last version
 267          * of a file.
 268          */
 269         if (i >= 0 && (*cp == ';' || *cp == '.')) {
 270                 /* This is to prevent matching of numeric extensions */
 271                 if (*cp == '.' && cp[1] != ';')
 272                         return 0;
 273                 while (--i >= 0)
 274                         if (*++cp != ';' && (*cp < '0' || *cp > '9'))
 275                                 return 0;
 276         }
 277         return 1;
 278 }
 279
 280 static int
 281 cd9660_open(const char *path, struct open_file *f)
 282 {
 283         struct file *fp = 0;
 284         void *buf;
 285         struct iso_primary_descriptor *vd;
 286         size_t buf_size, read, dsize, off;
 287         daddr_t bno, boff;
 288         struct iso_directory_record rec;
 289         struct iso_directory_record *dp = 0;
 290         int rc, first, use_rrip, lenskip;
 291
 292         /* First find the volume descriptor */
 293         buf = malloc(buf_size = ISO_DEFAULT_BLOCK_SIZE);
 294         vd = buf;
 295         for (bno = 16;; bno++) {
 296                 twiddle();
 297                 rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
 298                                            ISO_DEFAULT_BLOCK_SIZE, buf, &read);
 299                 if (rc)
 300                         goto out;
 301                 if (read != ISO_DEFAULT_BLOCK_SIZE) {
 302                         rc = EIO;
 303                         goto out;
 304                 }
 305                 rc = EINVAL;
 306                 if (bcmp(vd->id, ISO_STANDARD_ID, sizeof vd->id) != 0)
 307                         goto out;
 308                 if (isonum_711(vd->type) == ISO_VD_END)
 309                         goto out;
 310                 if (isonum_711(vd->type) == ISO_VD_PRIMARY)
 311                         break;
 312         }
 313         if (isonum_723(vd->logical_block_size) != ISO_DEFAULT_BLOCK_SIZE)
 314                 goto out;
 315
 316         rec = *(struct iso_directory_record *) vd->root_directory_record;
 317         if (*path == '/') path++; /* eat leading '/' */
 318
 319         first = 1;
 320         use_rrip = 0;
 321         while (*path) {
 322                 bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
 323                 dsize = isonum_733(rec.size);
 324                 off = 0;
 325                 boff = 0;
 326
 327                 while (off < dsize) {
 328                         if ((off % ISO_DEFAULT_BLOCK_SIZE) == 0) {
 329                                 twiddle();
 330                                 rc = f->f_dev->dv_strategy
 331                                         (f->f_devdata, F_READ,
 332                                          cdb2devb(bno + boff),
 333                                          ISO_DEFAULT_BLOCK_SIZE,
 334                                          buf, &read);
 335                                 if (rc)
 336                                         goto out;
 337                                 if (read != ISO_DEFAULT_BLOCK_SIZE) {
 338                                         rc = EIO;
 339                                         goto out;
 340                                 }
 341                                 boff++;
 342                                 dp = (struct iso_directory_record *) buf;
 343                         }
 344                         if (isonum_711(dp->length) == 0) {
 345                             /* skip to next block, if any */
 346                             off = boff * ISO_DEFAULT_BLOCK_SIZE;
 347                             continue;
 348                         }
 349
 350                         /* See if RRIP is in use. */
 351                         if (first)
 352                                 use_rrip = rrip_check(f, dp, &lenskip);
 353
 354                         if (dirmatch(f, path, dp, use_rrip,
 355                                 first ? 0 : lenskip)) {
 356                                 first = 0;
 357                                 break;
 358                         } else
 359                                 first = 0;
 360
 361                         dp = (struct iso_directory_record *)
 362                                 ((char *) dp + isonum_711(dp->length));
 363                         off += isonum_711(dp->length);
 364                 }
 365                 if (off >= dsize) {
 366                         rc = ENOENT;
 367                         goto out;
 368                 }
 369
 370                 rec = *dp;
 371                 while (*path && *path != '/') /* look for next component */
 372                         path++;
 373                 if (*path == '/') {     /* skip /, make sure is dir */
 374                         path++;
 375                         if (*path && (isonum_711(dp->flags) & 2) == 0) {
 376                                 rc = ENOENT;    /* not directory */
 377                                 goto out;
 378                         }
 379                 }
 380         }
 381
 382         /* allocate file system specific data structure */
 383         fp = malloc(sizeof(struct file));
 384         bzero(fp, sizeof(struct file));
 385         f->f_fsdata = (void *)fp;
 386
 387         if ((isonum_711(rec.flags) & 2) != 0) {
 388                 fp->f_flags = F_ISDIR;
 389         }
 390         if (first) {
 391                 fp->f_flags |= F_ROOTDIR;
 392
 393                 /* Check for Rock Ridge since we didn't in the loop above. */
 394                 bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
 395                 twiddle();
 396                 rc = f->f_dev->dv_strategy(f->f_devdata, F_READ, cdb2devb(bno),
 397                     ISO_DEFAULT_BLOCK_SIZE, buf, &read);
 398                 if (rc)
 399                         goto out;
 400                 if (read != ISO_DEFAULT_BLOCK_SIZE) {
 401                         rc = EIO;
 402                         goto out;
 403                 }
 404                 dp = (struct iso_directory_record *)buf;
 405                 use_rrip = rrip_check(f, dp, &lenskip);
 406         }
 407         if (use_rrip) {
 408                 fp->f_flags |= F_RR;
 409                 fp->f_susp_skip = lenskip;
 410         }
 411         fp->f_off = 0;
 412         fp->f_bno = isonum_733(rec.extent) + isonum_711(rec.ext_attr_length);
 413         fp->f_size = isonum_733(rec.size);
 414         free(buf);
 415
 416         return 0;
 417
 418 out:
 419         f->f_fsdata = NULL;
 420         if (fp)
 421                 free(fp);
 422         free(buf);
 423
 424         return rc;
 425 }
 426
 427 static int
 428 cd9660_close(struct open_file *f)
 429 {
 430         struct file *fp = (struct file *)f->f_fsdata;
 431
 432         f->f_fsdata = NULL;
 433         if (fp)
 434                 free(fp);
 435
 436         return 0;
 437 }
 438
 439 static int
 440 buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
 441 {
 442         struct file *fp = (struct file *)f->f_fsdata;
 443         daddr_t blkno, blkoff;
 444         int rc = 0;
 445         size_t read;
 446
 447         blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE + fp->f_bno;
 448         blkoff = fp->f_off % ISO_DEFAULT_BLOCK_SIZE;
 449
 450         if (blkno != fp->f_buf_blkno) {
 451                 if (fp->f_buf == NULL)
 452                         fp->f_buf = malloc(ISO_DEFAULT_BLOCK_SIZE);
 453
 454                 twiddle();
 455                 rc = f->f_dev->dv_strategy(f->f_devdata, F_READ,
 456                     cdb2devb(blkno), ISO_DEFAULT_BLOCK_SIZE, fp->f_buf, &read);
 457                 if (rc)
 458                         return (rc);
 459                 if (read != ISO_DEFAULT_BLOCK_SIZE)
 460                         return (EIO);
 461
 462                 fp->f_buf_blkno = blkno;
 463         }
 464
 465         *buf_p = fp->f_buf + blkoff;
 466         *size_p = ISO_DEFAULT_BLOCK_SIZE - blkoff;
 467
 468         if (*size_p > fp->f_size - fp->f_off)
 469                 *size_p = fp->f_size - fp->f_off;
 470         return (rc);
 471 }
 472
 473 static int
 474 cd9660_read(struct open_file *f, void *start, size_t size, size_t *resid)
 475 {
 476         struct file *fp = (struct file *)f->f_fsdata;
 477         char *buf, *addr;
 478         size_t buf_size, csize;
 479         int rc = 0;
 480
 481         addr = start;
 482         while (size) {
 483                 if (fp->f_off < 0 || fp->f_off >= fp->f_size)
 484                         break;
 485
 486                 rc = buf_read_file(f, &buf, &buf_size);
 487                 if (rc)
 488                         break;
 489
 490                 csize = size > buf_size ? buf_size : size;
 491                 bcopy(buf, addr, csize);
 492
 493                 fp->f_off += csize;
 494                 addr += csize;
 495                 size -= csize;
 496         }
 497         if (resid)
 498                 *resid = size;
 499         return (rc);
 500 }
 501
 502 static int
 503 cd9660_readdir(struct open_file *f, struct dirent *d)
 504 {
 505         struct file *fp = (struct file *)f->f_fsdata;
 506         struct iso_directory_record *ep;
 507         size_t buf_size, reclen, namelen;
 508         int error = 0;
 509         int lenskip;
 510         char *buf, *name;
 511
 512 again:
 513         if (fp->f_off >= fp->f_size)
 514                 return (ENOENT);
 515         error = buf_read_file(f, &buf, &buf_size);
 516         if (error)
 517                 return (error);
 518         ep = (struct iso_directory_record *)buf;
 519
 520         if (isonum_711(ep->length) == 0) {
 521                 daddr_t blkno;
 522
 523                 /* skip to next block, if any */
 524                 blkno = fp->f_off / ISO_DEFAULT_BLOCK_SIZE;
 525                 fp->f_off = (blkno + 1) * ISO_DEFAULT_BLOCK_SIZE;
 526                 goto again;
 527         }
 528
 529         if (fp->f_flags & F_RR) {
 530                 if (fp->f_flags & F_ROOTDIR && fp->f_off == 0)
 531                         lenskip = 0;
 532                 else
 533                         lenskip = fp->f_susp_skip;
 534                 name = rrip_lookup_name(f, ep, lenskip, &namelen);
 535         } else
 536                 name = NULL;
 537         if (name == NULL) {
 538                 namelen = isonum_711(ep->name_len);
 539                 name = ep->name;
 540                 if (namelen == 1) {
 541                         if (ep->name[0] == 0)
 542                                 name = ".";
 543                         else if (ep->name[0] == 1) {
 544                                 namelen = 2;
 545                                 name = "..";
 546                         }
 547                 }
 548         }
 549         reclen = _DIRENT_RECLEN(namelen);
 550
 551         d->d_ino = isonum_733(ep->extent);
 552         if (isonum_711(ep->flags) & 2)
 553                 d->d_type = DT_DIR;
 554         else
 555                 d->d_type = DT_REG;
 556         d->d_namlen = namelen;
 557
 558         bcopy(name, d->d_name, d->d_namlen);
 559         d->d_name[d->d_namlen] = 0;
 560
 561         fp->f_off += isonum_711(ep->length);
 562         return (0);
 563 }
 564
 565 static int
 566 cd9660_write(struct open_file *f, void *start, size_t size, size_t *resid)
 567 {
 568         return EROFS;
 569 }
 570
 571 static off_t
 572 cd9660_seek(struct open_file *f, off_t offset, int where)
 573 {
 574         struct file *fp = (struct file *)f->f_fsdata;
 575
 576         switch (where) {
 577         case SEEK_SET:
 578                 fp->f_off = offset;
 579                 break;
 580         case SEEK_CUR:
 581                 fp->f_off += offset;
 582                 break;
 583         case SEEK_END:
 584                 fp->f_off = fp->f_size - offset;
 585                 break;
 586         default:
 587                 return -1;
 588         }
 589         return fp->f_off;
 590 }
 591
 592 static int
 593 cd9660_stat(struct open_file *f, struct stat *sb)
 594 {
 595         struct file *fp = (struct file *)f->f_fsdata;
 596
 597         /* only important stuff */
 598         sb->st_mode = S_IRUSR | S_IRGRP | S_IROTH;
 599         if (fp->f_flags & F_ISDIR)
 600                 sb->st_mode |= S_IFDIR;
 601         else
 602                 sb->st_mode |= S_IFREG;
 603         sb->st_uid = sb->st_gid = 0;
 604         sb->st_size = fp->f_size;
 605         return 0;
 606 }