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 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 35 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/namei.h> 44 #include <sys/bio.h> 45 #include <sys/buf.h> 46 #include <sys/vnode.h> 47 #include <sys/mount.h> 48 49 #include <isofs/cd9660/iso.h> 50 #include <isofs/cd9660/cd9660_node.h> 51 #include <isofs/cd9660/iso_rrip.h> 52 53 /* 54 * Convert a component of a pathname into a pointer to a locked inode. 55 * This is a very central and rather complicated routine. 56 * If the filesystem is not maintained in a strict tree hierarchy, 57 * this can result in a deadlock situation (see comments in code below). 58 * 59 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 60 * whether the name is to be looked up, created, renamed, or deleted. 61 * When CREATE, RENAME, or DELETE is specified, information usable in 62 * creating, renaming, or deleting a directory entry may be calculated. 63 * If flag has LOCKPARENT or'ed into it and the target of the pathname 64 * exists, lookup returns both the target and its parent directory locked. 65 * When creating or renaming and LOCKPARENT is specified, the target may 66 * not be ".". When deleting and LOCKPARENT is specified, the target may 67 * be "."., but the caller must check to ensure it does an vrele and iput 68 * instead of two iputs. 69 * 70 * Overall outline of ufs_lookup: 71 * 72 * search for name in directory, to found or notfound 73 * notfound: 74 * if creating, return locked directory, leaving info on available slots 75 * else return error 76 * found: 77 * if at end of path and deleting, return information to allow delete 78 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 79 * inode and return info to allow rewrite 80 * if not at end, add name to cache; if at end and neither creating 81 * nor deleting, add name to cache 82 * 83 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. 84 */ 85 int 86 cd9660_lookup(ap) 87 struct vop_cachedlookup_args /* { 88 struct vnode *a_dvp; 89 struct vnode **a_vpp; 90 struct componentname *a_cnp; 91 } */ *ap; 92 { 93 struct vnode *vdp; /* vnode for directory being searched */ 94 struct iso_node *dp; /* inode for directory being searched */ 95 struct iso_mnt *imp; /* filesystem that directory is in */ 96 struct buf *bp; /* a buffer of directory entries */ 97 struct iso_directory_record *ep = 0;/* the current directory entry */ 98 int entryoffsetinblock; /* offset of ep in bp's buffer */ 99 int saveoffset = 0; /* offset of last directory entry in dir */ 100 int numdirpasses; /* strategy for directory search */ 101 doff_t endsearch; /* offset to end directory search */ 102 struct vnode *pdp; /* saved dp during symlink work */ 103 struct vnode *tdp; /* returned by cd9660_vget_internal */ 104 u_long bmask; /* block offset mask */ 105 int lockparent; /* 1 => lockparent flag is set */ 106 int error; 107 ino_t ino = 0; 108 int reclen; 109 u_short namelen; 110 int isoflags; 111 char altname[NAME_MAX]; 112 int res; 113 int assoc, len; 114 char *name; 115 struct vnode **vpp = ap->a_vpp; 116 struct componentname *cnp = ap->a_cnp; 117 int flags = cnp->cn_flags; 118 int nameiop = cnp->cn_nameiop; 119 struct thread *td = cnp->cn_thread; 120 121 bp = NULL; 122 *vpp = NULL; 123 vdp = ap->a_dvp; 124 dp = VTOI(vdp); 125 imp = dp->i_mnt; 126 lockparent = flags & LOCKPARENT; 127 cnp->cn_flags &= ~PDIRUNLOCK; 128 129 /* 130 * We now have a segment name to search for, and a directory to search. 131 */ 132 133 len = cnp->cn_namelen; 134 name = cnp->cn_nameptr; 135 /* 136 * A leading `=' means, we are looking for an associated file 137 */ 138 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) 139 { 140 len--; 141 name++; 142 } 143 144 /* 145 * If there is cached information on a previous search of 146 * this directory, pick up where we last left off. 147 * We cache only lookups as these are the most common 148 * and have the greatest payoff. Caching CREATE has little 149 * benefit as it usually must search the entire directory 150 * to determine that the entry does not exist. Caching the 151 * location of the last DELETE or RENAME has not reduced 152 * profiling time and hence has been removed in the interest 153 * of simplicity. 154 */ 155 bmask = imp->im_bmask; 156 if (nameiop != LOOKUP || dp->i_diroff == 0 || 157 dp->i_diroff > dp->i_size) { 158 entryoffsetinblock = 0; 159 dp->i_offset = 0; 160 numdirpasses = 1; 161 } else { 162 dp->i_offset = dp->i_diroff; 163 if ((entryoffsetinblock = dp->i_offset & bmask) && 164 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp))) 165 return (error); 166 numdirpasses = 2; 167 nchstats.ncs_2passes++; 168 } 169 endsearch = dp->i_size; 170 171 searchloop: 172 while (dp->i_offset < endsearch) { 173 /* 174 * If offset is on a block boundary, 175 * read the next directory block. 176 * Release previous if it exists. 177 */ 178 if ((dp->i_offset & bmask) == 0) { 179 if (bp != NULL) 180 brelse(bp); 181 if ((error = 182 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0) 183 return (error); 184 entryoffsetinblock = 0; 185 } 186 /* 187 * Get pointer to next entry. 188 */ 189 ep = (struct iso_directory_record *) 190 ((char *)bp->b_data + entryoffsetinblock); 191 192 reclen = isonum_711(ep->length); 193 if (reclen == 0) { 194 /* skip to next block, if any */ 195 dp->i_offset = 196 (dp->i_offset & ~bmask) + imp->logical_block_size; 197 continue; 198 } 199 200 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 201 /* illegal entry, stop */ 202 break; 203 204 if (entryoffsetinblock + reclen > imp->logical_block_size) 205 /* entries are not allowed to cross boundaries */ 206 break; 207 208 namelen = isonum_711(ep->name_len); 209 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 210 &ep->date[6]: ep->flags); 211 212 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 213 /* illegal entry, stop */ 214 break; 215 216 /* 217 * Check for a name match. 218 */ 219 switch (imp->iso_ftype) { 220 default: 221 if (!(isoflags & 4) == !assoc) { 222 if ((len == 1 223 && *name == '.') 224 || (flags & ISDOTDOT)) { 225 if (namelen == 1 226 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 227 /* 228 * Save directory entry's inode number and 229 * release directory buffer. 230 */ 231 dp->i_ino = isodirino(ep, imp); 232 goto found; 233 } 234 if (namelen != 1 235 || ep->name[0] != 0) 236 goto notfound; 237 } else if (!(res = isofncmp(name, len, 238 ep->name, namelen, 239 imp->joliet_level, 240 imp->im_flags, 241 imp->im_d2l, 242 imp->im_l2d))) { 243 if (isoflags & 2) 244 ino = isodirino(ep, imp); 245 else 246 ino = dbtob(bp->b_blkno) 247 + entryoffsetinblock; 248 saveoffset = dp->i_offset; 249 } else if (ino) 250 goto foundino; 251 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 252 else if (res < 0) 253 goto notfound; 254 else if (res > 0 && numdirpasses == 2) 255 numdirpasses++; 256 #endif 257 } 258 break; 259 case ISO_FTYPE_RRIP: 260 if (isonum_711(ep->flags)&2) 261 ino = isodirino(ep, imp); 262 else 263 ino = dbtob(bp->b_blkno) + entryoffsetinblock; 264 dp->i_ino = ino; 265 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); 266 if (namelen == cnp->cn_namelen 267 && !bcmp(name,altname,namelen)) 268 goto found; 269 ino = 0; 270 break; 271 } 272 dp->i_offset += reclen; 273 entryoffsetinblock += reclen; 274 } 275 if (ino) { 276 foundino: 277 dp->i_ino = ino; 278 if (saveoffset != dp->i_offset) { 279 if (lblkno(imp, dp->i_offset) != 280 lblkno(imp, saveoffset)) { 281 if (bp != NULL) 282 brelse(bp); 283 if ((error = cd9660_blkatoff(vdp, 284 (off_t)saveoffset, NULL, &bp)) != 0) 285 return (error); 286 } 287 entryoffsetinblock = saveoffset & bmask; 288 ep = (struct iso_directory_record *) 289 ((char *)bp->b_data + entryoffsetinblock); 290 dp->i_offset = saveoffset; 291 } 292 goto found; 293 } 294 notfound: 295 /* 296 * If we started in the middle of the directory and failed 297 * to find our target, we must check the beginning as well. 298 */ 299 if (numdirpasses == 2) { 300 numdirpasses--; 301 dp->i_offset = 0; 302 endsearch = dp->i_diroff; 303 goto searchloop; 304 } 305 if (bp != NULL) 306 brelse(bp); 307 308 /* 309 * Insert name into cache (as non-existent) if appropriate. 310 */ 311 if (cnp->cn_flags & MAKEENTRY) 312 cache_enter(vdp, *vpp, cnp); 313 if (nameiop == CREATE || nameiop == RENAME) 314 return (EROFS); 315 return (ENOENT); 316 317 found: 318 if (numdirpasses == 2) 319 nchstats.ncs_pass2++; 320 321 /* 322 * Found component in pathname. 323 * If the final component of path name, save information 324 * in the cache as to where the entry was found. 325 */ 326 if ((flags & ISLASTCN) && nameiop == LOOKUP) 327 dp->i_diroff = dp->i_offset; 328 329 /* 330 * Step through the translation in the name. We do not `iput' the 331 * directory because we may need it again if a symbolic link 332 * is relative to the current directory. Instead we save it 333 * unlocked as "pdp". We must get the target inode before unlocking 334 * the directory to insure that the inode will not be removed 335 * before we get it. We prevent deadlock by always fetching 336 * inodes from the root, moving down the directory tree. Thus 337 * when following backward pointers ".." we must unlock the 338 * parent directory before getting the requested directory. 339 * There is a potential race condition here if both the current 340 * and parent directories are removed before the `iget' for the 341 * inode associated with ".." returns. We hope that this occurs 342 * infrequently since we cannot avoid this race condition without 343 * implementing a sophisticated deadlock detection algorithm. 344 * Note also that this simple deadlock detection scheme will not 345 * work if the filesystem has any hard links other than ".." 346 * that point backwards in the directory structure. 347 */ 348 pdp = vdp; 349 /* 350 * If ino is different from dp->i_ino, 351 * it's a relocated directory. 352 */ 353 if (flags & ISDOTDOT) { 354 VOP_UNLOCK(pdp, 0, td); /* race to get the inode */ 355 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, 356 LK_EXCLUSIVE, &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, 378 LK_EXCLUSIVE, &tdp, 379 dp->i_ino != ino, ep); 380 brelse(bp); 381 if (error) 382 return (error); 383 if (!lockparent || !(flags & ISLASTCN)) { 384 cnp->cn_flags |= PDIRUNLOCK; 385 VOP_UNLOCK(pdp, 0, td); 386 } 387 *vpp = tdp; 388 } 389 390 /* 391 * Insert name into cache if appropriate. 392 */ 393 if (cnp->cn_flags & MAKEENTRY) 394 cache_enter(vdp, *vpp, cnp); 395 return (0); 396 } 397 398 /* 399 * Return buffer with the contents of block "offset" from the beginning of 400 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 401 * remaining space in the directory. 402 */ 403 int 404 cd9660_blkatoff(vp, offset, res, bpp) 405 struct vnode *vp; 406 off_t offset; 407 char **res; 408 struct buf **bpp; 409 { 410 struct iso_node *ip; 411 struct iso_mnt *imp; 412 struct buf *bp; 413 daddr_t lbn; 414 int bsize, bshift, error; 415 416 ip = VTOI(vp); 417 imp = ip->i_mnt; 418 lbn = lblkno(imp, offset); 419 bsize = blksize(imp, ip, lbn); 420 bshift = imp->im_bshift; 421 422 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 423 brelse(bp); 424 *bpp = NULL; 425 return (error); 426 } 427 428 /* 429 * We must BMAP the buffer because the directory code may use b_blkno 430 * to calculate the inode for certain types of directory entries. 431 * We could get away with not doing it before we VMIO-backed the 432 * directories because the buffers would get freed atomically with 433 * the invalidation of their data. But with VMIO-backed buffers 434 * the buffers may be freed and then later reconstituted - and the 435 * reconstituted buffer will have no knowledge of b_blkno. 436 */ 437 if (bp->b_blkno == bp->b_lblkno) { 438 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT); 439 } 440 441 if (res) 442 *res = (char *)bp->b_data + blkoff(imp, offset); 443 *bpp = bp; 444 return (0); 445 } 446