| 1 | /*- |
| 2 | * Copyright (c) 1989, 1993, 1994 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * This code is derived from software contributed to Berkeley |
| 6 | * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension |
| 7 | * Support code is derived from software contributed to Berkeley |
| 8 | * by Atsushi Murai (amurai@spec.co.jp). |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * 3. All advertising materials mentioning features or use of this software |
| 19 | * must display the following acknowledgement: |
| 20 | * This product includes software developed by the University of |
| 21 | * California, Berkeley and its contributors. |
| 22 | * 4. Neither the name of the University nor the names of its contributors |
| 23 | * may be used to endorse or promote products derived from this software |
| 24 | * without specific prior written permission. |
| 25 | * |
| 26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 36 | * SUCH DAMAGE. |
| 37 | * |
| 38 | * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 |
| 39 | * |
| 40 | * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94 |
| 41 | * $FreeBSD: src/sys/isofs/cd9660/cd9660_lookup.c,v 1.23.2.2 2001/11/04 06:19:47 dillon Exp $ |
| 42 | * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_lookup.c,v 1.5 2003/07/26 19:27:41 rob Exp $ |
| 43 | */ |
| 44 | |
| 45 | #include <sys/param.h> |
| 46 | #include <sys/systm.h> |
| 47 | #include <sys/proc.h> |
| 48 | #include <sys/namei.h> |
| 49 | #include <sys/buf.h> |
| 50 | #include <sys/vnode.h> |
| 51 | #include <sys/mount.h> |
| 52 | |
| 53 | #include <isofs/cd9660/iso.h> |
| 54 | #include <isofs/cd9660/cd9660_node.h> |
| 55 | #include <isofs/cd9660/iso_rrip.h> |
| 56 | |
| 57 | /* |
| 58 | * Convert a component of a pathname into a pointer to a locked inode. |
| 59 | * This is a very central and rather complicated routine. |
| 60 | * If the file system is not maintained in a strict tree hierarchy, |
| 61 | * this can result in a deadlock situation (see comments in code below). |
| 62 | * |
| 63 | * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on |
| 64 | * whether the name is to be looked up, created, renamed, or deleted. |
| 65 | * When CREATE, RENAME, or DELETE is specified, information usable in |
| 66 | * creating, renaming, or deleting a directory entry may be calculated. |
| 67 | * If flag has LOCKPARENT or'ed into it and the target of the pathname |
| 68 | * exists, lookup returns both the target and its parent directory locked. |
| 69 | * When creating or renaming and LOCKPARENT is specified, the target may |
| 70 | * not be ".". When deleting and LOCKPARENT is specified, the target may |
| 71 | * be "."., but the caller must check to ensure it does an vrele and iput |
| 72 | * instead of two iputs. |
| 73 | * |
| 74 | * Overall outline of ufs_lookup: |
| 75 | * |
| 76 | * search for name in directory, to found or notfound |
| 77 | * notfound: |
| 78 | * if creating, return locked directory, leaving info on available slots |
| 79 | * else return error |
| 80 | * found: |
| 81 | * if at end of path and deleting, return information to allow delete |
| 82 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target |
| 83 | * inode and return info to allow rewrite |
| 84 | * if not at end, add name to cache; if at end and neither creating |
| 85 | * nor deleting, add name to cache |
| 86 | * |
| 87 | * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. |
| 88 | */ |
| 89 | int |
| 90 | cd9660_lookup(ap) |
| 91 | struct vop_cachedlookup_args /* { |
| 92 | struct vnode *a_dvp; |
| 93 | struct vnode **a_vpp; |
| 94 | struct componentname *a_cnp; |
| 95 | } */ *ap; |
| 96 | { |
| 97 | struct vnode *vdp; /* vnode for directory being searched */ |
| 98 | struct iso_node *dp; /* inode for directory being searched */ |
| 99 | struct iso_mnt *imp; /* file system that directory is in */ |
| 100 | struct buf *bp; /* a buffer of directory entries */ |
| 101 | struct iso_directory_record *ep = 0;/* the current directory entry */ |
| 102 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
| 103 | int saveoffset = 0; /* offset of last directory entry in dir */ |
| 104 | int numdirpasses; /* strategy for directory search */ |
| 105 | doff_t endsearch; /* offset to end directory search */ |
| 106 | struct vnode *pdp; /* saved dp during symlink work */ |
| 107 | struct vnode *tdp; /* returned by cd9660_vget_internal */ |
| 108 | u_long bmask; /* block offset mask */ |
| 109 | int lockparent; /* 1 => lockparent flag is set */ |
| 110 | int wantparent; /* 1 => wantparent or lockparent flag */ |
| 111 | int error; |
| 112 | ino_t ino = 0; |
| 113 | int reclen; |
| 114 | u_short namelen; |
| 115 | int isoflags; |
| 116 | char altname[NAME_MAX]; |
| 117 | int res; |
| 118 | int assoc, len; |
| 119 | char *name; |
| 120 | struct vnode **vpp = ap->a_vpp; |
| 121 | struct componentname *cnp = ap->a_cnp; |
| 122 | int flags = cnp->cn_flags; |
| 123 | int nameiop = cnp->cn_nameiop; |
| 124 | struct thread *td = cnp->cn_td; |
| 125 | |
| 126 | bp = NULL; |
| 127 | *vpp = NULL; |
| 128 | vdp = ap->a_dvp; |
| 129 | dp = VTOI(vdp); |
| 130 | imp = dp->i_mnt; |
| 131 | lockparent = flags & LOCKPARENT; |
| 132 | wantparent = flags & (LOCKPARENT|WANTPARENT); |
| 133 | cnp->cn_flags &= ~PDIRUNLOCK; |
| 134 | |
| 135 | /* |
| 136 | * We now have a segment name to search for, and a directory to search. |
| 137 | */ |
| 138 | |
| 139 | len = cnp->cn_namelen; |
| 140 | name = cnp->cn_nameptr; |
| 141 | /* |
| 142 | * A leading `=' means, we are looking for an associated file |
| 143 | */ |
| 144 | if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) |
| 145 | { |
| 146 | len--; |
| 147 | name++; |
| 148 | } |
| 149 | |
| 150 | /* |
| 151 | * If there is cached information on a previous search of |
| 152 | * this directory, pick up where we last left off. |
| 153 | * We cache only lookups as these are the most common |
| 154 | * and have the greatest payoff. Caching CREATE has little |
| 155 | * benefit as it usually must search the entire directory |
| 156 | * to determine that the entry does not exist. Caching the |
| 157 | * location of the last DELETE or RENAME has not reduced |
| 158 | * profiling time and hence has been removed in the interest |
| 159 | * of simplicity. |
| 160 | */ |
| 161 | bmask = imp->im_bmask; |
| 162 | if (nameiop != LOOKUP || dp->i_diroff == 0 || |
| 163 | dp->i_diroff > dp->i_size) { |
| 164 | entryoffsetinblock = 0; |
| 165 | dp->i_offset = 0; |
| 166 | numdirpasses = 1; |
| 167 | } else { |
| 168 | dp->i_offset = dp->i_diroff; |
| 169 | if ((entryoffsetinblock = dp->i_offset & bmask) && |
| 170 | (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp))) |
| 171 | return (error); |
| 172 | numdirpasses = 2; |
| 173 | nchstats.ncs_2passes++; |
| 174 | } |
| 175 | endsearch = dp->i_size; |
| 176 | |
| 177 | searchloop: |
| 178 | while (dp->i_offset < endsearch) { |
| 179 | /* |
| 180 | * If offset is on a block boundary, |
| 181 | * read the next directory block. |
| 182 | * Release previous if it exists. |
| 183 | */ |
| 184 | if ((dp->i_offset & bmask) == 0) { |
| 185 | if (bp != NULL) |
| 186 | brelse(bp); |
| 187 | if ((error = |
| 188 | cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0) |
| 189 | return (error); |
| 190 | entryoffsetinblock = 0; |
| 191 | } |
| 192 | /* |
| 193 | * Get pointer to next entry. |
| 194 | */ |
| 195 | ep = (struct iso_directory_record *) |
| 196 | ((char *)bp->b_data + entryoffsetinblock); |
| 197 | |
| 198 | reclen = isonum_711(ep->length); |
| 199 | if (reclen == 0) { |
| 200 | /* skip to next block, if any */ |
| 201 | dp->i_offset = |
| 202 | (dp->i_offset & ~bmask) + imp->logical_block_size; |
| 203 | continue; |
| 204 | } |
| 205 | |
| 206 | if (reclen < ISO_DIRECTORY_RECORD_SIZE) |
| 207 | /* illegal entry, stop */ |
| 208 | break; |
| 209 | |
| 210 | if (entryoffsetinblock + reclen > imp->logical_block_size) |
| 211 | /* entries are not allowed to cross boundaries */ |
| 212 | break; |
| 213 | |
| 214 | namelen = isonum_711(ep->name_len); |
| 215 | isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? |
| 216 | &ep->date[6]: ep->flags); |
| 217 | |
| 218 | if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) |
| 219 | /* illegal entry, stop */ |
| 220 | break; |
| 221 | |
| 222 | /* |
| 223 | * Check for a name match. |
| 224 | */ |
| 225 | switch (imp->iso_ftype) { |
| 226 | default: |
| 227 | if (!(isoflags & 4) == !assoc) { |
| 228 | if ((len == 1 |
| 229 | && *name == '.') |
| 230 | || (flags & ISDOTDOT)) { |
| 231 | if (namelen == 1 |
| 232 | && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { |
| 233 | /* |
| 234 | * Save directory entry's inode number and |
| 235 | * release directory buffer. |
| 236 | */ |
| 237 | dp->i_ino = isodirino(ep, imp); |
| 238 | goto found; |
| 239 | } |
| 240 | if (namelen != 1 |
| 241 | || ep->name[0] != 0) |
| 242 | goto notfound; |
| 243 | } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) { |
| 244 | if (isoflags & 2) |
| 245 | ino = isodirino(ep, imp); |
| 246 | else |
| 247 | ino = dbtob(bp->b_blkno) |
| 248 | + entryoffsetinblock; |
| 249 | saveoffset = dp->i_offset; |
| 250 | } else if (ino) |
| 251 | goto foundino; |
| 252 | #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ |
| 253 | else if (res < 0) |
| 254 | goto notfound; |
| 255 | else if (res > 0 && numdirpasses == 2) |
| 256 | numdirpasses++; |
| 257 | #endif |
| 258 | } |
| 259 | break; |
| 260 | case ISO_FTYPE_RRIP: |
| 261 | if (isonum_711(ep->flags)&2) |
| 262 | ino = isodirino(ep, imp); |
| 263 | else |
| 264 | ino = dbtob(bp->b_blkno) + entryoffsetinblock; |
| 265 | dp->i_ino = ino; |
| 266 | cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); |
| 267 | if (namelen == cnp->cn_namelen |
| 268 | && !bcmp(name,altname,namelen)) |
| 269 | goto found; |
| 270 | ino = 0; |
| 271 | break; |
| 272 | } |
| 273 | dp->i_offset += reclen; |
| 274 | entryoffsetinblock += reclen; |
| 275 | } |
| 276 | if (ino) { |
| 277 | foundino: |
| 278 | dp->i_ino = ino; |
| 279 | if (saveoffset != dp->i_offset) { |
| 280 | if (lblkno(imp, dp->i_offset) != |
| 281 | lblkno(imp, saveoffset)) { |
| 282 | if (bp != NULL) |
| 283 | brelse(bp); |
| 284 | if ((error = cd9660_blkatoff(vdp, |
| 285 | (off_t)saveoffset, NULL, &bp)) != 0) |
| 286 | return (error); |
| 287 | } |
| 288 | entryoffsetinblock = saveoffset & bmask; |
| 289 | ep = (struct iso_directory_record *) |
| 290 | ((char *)bp->b_data + entryoffsetinblock); |
| 291 | dp->i_offset = saveoffset; |
| 292 | } |
| 293 | goto found; |
| 294 | } |
| 295 | notfound: |
| 296 | /* |
| 297 | * If we started in the middle of the directory and failed |
| 298 | * to find our target, we must check the beginning as well. |
| 299 | */ |
| 300 | if (numdirpasses == 2) { |
| 301 | numdirpasses--; |
| 302 | dp->i_offset = 0; |
| 303 | endsearch = dp->i_diroff; |
| 304 | goto searchloop; |
| 305 | } |
| 306 | if (bp != NULL) |
| 307 | brelse(bp); |
| 308 | |
| 309 | /* |
| 310 | * Insert name into cache (as non-existent) if appropriate. |
| 311 | */ |
| 312 | if (cnp->cn_flags & MAKEENTRY) |
| 313 | cache_enter(vdp, *vpp, cnp); |
| 314 | if (nameiop == CREATE || nameiop == RENAME) |
| 315 | return (EROFS); |
| 316 | return (ENOENT); |
| 317 | |
| 318 | found: |
| 319 | if (numdirpasses == 2) |
| 320 | nchstats.ncs_pass2++; |
| 321 | |
| 322 | /* |
| 323 | * Found component in pathname. |
| 324 | * If the final component of path name, save information |
| 325 | * in the cache as to where the entry was found. |
| 326 | */ |
| 327 | if ((flags & ISLASTCN) && nameiop == LOOKUP) |
| 328 | dp->i_diroff = dp->i_offset; |
| 329 | |
| 330 | /* |
| 331 | * Step through the translation in the name. We do not `iput' the |
| 332 | * directory because we may need it again if a symbolic link |
| 333 | * is relative to the current directory. Instead we save it |
| 334 | * unlocked as "pdp". We must get the target inode before unlocking |
| 335 | * the directory to insure that the inode will not be removed |
| 336 | * before we get it. We prevent deadlock by always fetching |
| 337 | * inodes from the root, moving down the directory tree. Thus |
| 338 | * when following backward pointers ".." we must unlock the |
| 339 | * parent directory before getting the requested directory. |
| 340 | * There is a potential race condition here if both the current |
| 341 | * and parent directories are removed before the `iget' for the |
| 342 | * inode associated with ".." returns. We hope that this occurs |
| 343 | * infrequently since we cannot avoid this race condition without |
| 344 | * implementing a sophisticated deadlock detection algorithm. |
| 345 | * Note also that this simple deadlock detection scheme will not |
| 346 | * work if the file system has any hard links other than ".." |
| 347 | * that point backwards in the directory structure. |
| 348 | */ |
| 349 | pdp = vdp; |
| 350 | /* |
| 351 | * If ino is different from dp->i_ino, |
| 352 | * it's a relocated directory. |
| 353 | */ |
| 354 | if (flags & ISDOTDOT) { |
| 355 | VOP_UNLOCK(pdp, 0, td); /* race to get the inode */ |
| 356 | error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, |
| 357 | dp->i_ino != ino, ep); |
| 358 | brelse(bp); |
| 359 | if (error) { |
| 360 | vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td); |
| 361 | return (error); |
| 362 | } |
| 363 | if (lockparent && (flags & ISLASTCN)) { |
| 364 | if ((error = vn_lock(pdp, LK_EXCLUSIVE, td)) != 0) { |
| 365 | cnp->cn_flags |= PDIRUNLOCK; |
| 366 | vput(tdp); |
| 367 | return (error); |
| 368 | } |
| 369 | } else |
| 370 | cnp->cn_flags |= PDIRUNLOCK; |
| 371 | *vpp = tdp; |
| 372 | } else if (dp->i_number == dp->i_ino) { |
| 373 | brelse(bp); |
| 374 | VREF(vdp); /* we want ourself, ie "." */ |
| 375 | *vpp = vdp; |
| 376 | } else { |
| 377 | error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, |
| 378 | dp->i_ino != ino, ep); |
| 379 | brelse(bp); |
| 380 | if (error) |
| 381 | return (error); |
| 382 | if (!lockparent || !(flags & ISLASTCN)) { |
| 383 | cnp->cn_flags |= PDIRUNLOCK; |
| 384 | VOP_UNLOCK(pdp, 0, td); |
| 385 | } |
| 386 | *vpp = tdp; |
| 387 | } |
| 388 | |
| 389 | /* |
| 390 | * Insert name into cache if appropriate. |
| 391 | */ |
| 392 | if (cnp->cn_flags & MAKEENTRY) |
| 393 | cache_enter(vdp, *vpp, cnp); |
| 394 | return (0); |
| 395 | } |
| 396 | |
| 397 | /* |
| 398 | * Return buffer with the contents of block "offset" from the beginning of |
| 399 | * directory "ip". If "res" is non-zero, fill it in with a pointer to the |
| 400 | * remaining space in the directory. |
| 401 | */ |
| 402 | int |
| 403 | cd9660_blkatoff(vp, offset, res, bpp) |
| 404 | struct vnode *vp; |
| 405 | off_t offset; |
| 406 | char **res; |
| 407 | struct buf **bpp; |
| 408 | { |
| 409 | struct iso_node *ip; |
| 410 | struct iso_mnt *imp; |
| 411 | struct buf *bp; |
| 412 | daddr_t lbn; |
| 413 | int bsize, error; |
| 414 | |
| 415 | ip = VTOI(vp); |
| 416 | imp = ip->i_mnt; |
| 417 | lbn = lblkno(imp, offset); |
| 418 | bsize = blksize(imp, ip, lbn); |
| 419 | |
| 420 | if ((error = bread(vp, lbn, bsize, &bp)) != 0) { |
| 421 | brelse(bp); |
| 422 | *bpp = NULL; |
| 423 | return (error); |
| 424 | } |
| 425 | |
| 426 | /* |
| 427 | * We must BMAP the buffer because the directory code may use b_blkno |
| 428 | * to calculate the inode for certain types of directory entries. |
| 429 | * We could get away with not doing it before we VMIO-backed the |
| 430 | * directories because the buffers would get freed atomically with |
| 431 | * the invalidation of their data. But with VMIO-backed buffers |
| 432 | * the buffers may be freed and then later reconstituted - and the |
| 433 | * reconstituted buffer will have no knowledge of b_blkno. |
| 434 | */ |
| 435 | if (bp->b_blkno == bp->b_lblkno) { |
| 436 | error = VOP_BMAP(vp, bp->b_lblkno, NULL, |
| 437 | &bp->b_blkno, NULL, NULL); |
| 438 | if (error) { |
| 439 | bp->b_error = error; |
| 440 | bp->b_flags |= B_ERROR; |
| 441 | brelse(bp); |
| 442 | *bpp = NULL; |
| 443 | return (error); |
| 444 | } |
| 445 | } |
| 446 | |
| 447 | if (res) |
| 448 | *res = (char *)bp->b_data + blkoff(imp, offset); |
| 449 | *bpp = bp; |
| 450 | return (0); |
| 451 | } |