usr/src/boot/lib/libstand/cd9660.c

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