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 1.2 2003/06/17 04:28:41 dillon Exp $ 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/namei.h> 48 #include <sys/buf.h> 49 #include <sys/vnode.h> 50 #include <sys/mount.h> 51 52 #include <isofs/cd9660/iso.h> 53 #include <isofs/cd9660/cd9660_node.h> 54 #include <isofs/cd9660/iso_rrip.h> 55 56 /* 57 * Convert a component of a pathname into a pointer to a locked inode. 58 * This is a very central and rather complicated routine. 59 * If the file system is not maintained in a strict tree hierarchy, 60 * this can result in a deadlock situation (see comments in code below). 61 * 62 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 63 * whether the name is to be looked up, created, renamed, or deleted. 64 * When CREATE, RENAME, or DELETE is specified, information usable in 65 * creating, renaming, or deleting a directory entry may be calculated. 66 * If flag has LOCKPARENT or'ed into it and the target of the pathname 67 * exists, lookup returns both the target and its parent directory locked. 68 * When creating or renaming and LOCKPARENT is specified, the target may 69 * not be ".". When deleting and LOCKPARENT is specified, the target may 70 * be "."., but the caller must check to ensure it does an vrele and iput 71 * instead of two iputs. 72 * 73 * Overall outline of ufs_lookup: 74 * 75 * search for name in directory, to found or notfound 76 * notfound: 77 * if creating, return locked directory, leaving info on available slots 78 * else return error 79 * found: 80 * if at end of path and deleting, return information to allow delete 81 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 82 * inode and return info to allow rewrite 83 * if not at end, add name to cache; if at end and neither creating 84 * nor deleting, add name to cache 85 * 86 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. 87 */ 88 int 89 cd9660_lookup(ap) 90 struct vop_cachedlookup_args /* { 91 struct vnode *a_dvp; 92 struct vnode **a_vpp; 93 struct componentname *a_cnp; 94 } */ *ap; 95 { 96 register struct vnode *vdp; /* vnode for directory being searched */ 97 register struct iso_node *dp; /* inode for directory being searched */ 98 register struct iso_mnt *imp; /* file system that directory is in */ 99 struct buf *bp; /* a buffer of directory entries */ 100 struct iso_directory_record *ep = 0;/* the current directory entry */ 101 int entryoffsetinblock; /* offset of ep in bp's buffer */ 102 int saveoffset = 0; /* offset of last directory entry in dir */ 103 int numdirpasses; /* strategy for directory search */ 104 doff_t endsearch; /* offset to end directory search */ 105 struct vnode *pdp; /* saved dp during symlink work */ 106 struct vnode *tdp; /* returned by cd9660_vget_internal */ 107 u_long bmask; /* block offset mask */ 108 int lockparent; /* 1 => lockparent flag is set */ 109 int wantparent; /* 1 => wantparent or lockparent flag */ 110 int error; 111 ino_t ino = 0; 112 int reclen; 113 u_short namelen; 114 int isoflags; 115 char altname[NAME_MAX]; 116 int res; 117 int assoc, len; 118 char *name; 119 struct vnode **vpp = ap->a_vpp; 120 struct componentname *cnp = ap->a_cnp; 121 int flags = cnp->cn_flags; 122 int nameiop = cnp->cn_nameiop; 123 struct proc *p = cnp->cn_proc; 124 125 bp = NULL; 126 *vpp = NULL; 127 vdp = ap->a_dvp; 128 dp = VTOI(vdp); 129 imp = dp->i_mnt; 130 lockparent = flags & LOCKPARENT; 131 wantparent = flags & (LOCKPARENT|WANTPARENT); 132 cnp->cn_flags &= ~PDIRUNLOCK; 133 134 /* 135 * We now have a segment name to search for, and a directory to search. 136 */ 137 138 len = cnp->cn_namelen; 139 name = cnp->cn_nameptr; 140 /* 141 * A leading `=' means, we are looking for an associated file 142 */ 143 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) 144 { 145 len--; 146 name++; 147 } 148 149 /* 150 * If there is cached information on a previous search of 151 * this directory, pick up where we last left off. 152 * We cache only lookups as these are the most common 153 * and have the greatest payoff. Caching CREATE has little 154 * benefit as it usually must search the entire directory 155 * to determine that the entry does not exist. Caching the 156 * location of the last DELETE or RENAME has not reduced 157 * profiling time and hence has been removed in the interest 158 * of simplicity. 159 */ 160 bmask = imp->im_bmask; 161 if (nameiop != LOOKUP || dp->i_diroff == 0 || 162 dp->i_diroff > dp->i_size) { 163 entryoffsetinblock = 0; 164 dp->i_offset = 0; 165 numdirpasses = 1; 166 } else { 167 dp->i_offset = dp->i_diroff; 168 if ((entryoffsetinblock = dp->i_offset & bmask) && 169 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp))) 170 return (error); 171 numdirpasses = 2; 172 nchstats.ncs_2passes++; 173 } 174 endsearch = dp->i_size; 175 176 searchloop: 177 while (dp->i_offset < endsearch) { 178 /* 179 * If offset is on a block boundary, 180 * read the next directory block. 181 * Release previous if it exists. 182 */ 183 if ((dp->i_offset & bmask) == 0) { 184 if (bp != NULL) 185 brelse(bp); 186 if ((error = 187 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0) 188 return (error); 189 entryoffsetinblock = 0; 190 } 191 /* 192 * Get pointer to next entry. 193 */ 194 ep = (struct iso_directory_record *) 195 ((char *)bp->b_data + entryoffsetinblock); 196 197 reclen = isonum_711(ep->length); 198 if (reclen == 0) { 199 /* skip to next block, if any */ 200 dp->i_offset = 201 (dp->i_offset & ~bmask) + imp->logical_block_size; 202 continue; 203 } 204 205 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 206 /* illegal entry, stop */ 207 break; 208 209 if (entryoffsetinblock + reclen > imp->logical_block_size) 210 /* entries are not allowed to cross boundaries */ 211 break; 212 213 namelen = isonum_711(ep->name_len); 214 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 215 &ep->date[6]: ep->flags); 216 217 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 218 /* illegal entry, stop */ 219 break; 220 221 /* 222 * Check for a name match. 223 */ 224 switch (imp->iso_ftype) { 225 default: 226 if (!(isoflags & 4) == !assoc) { 227 if ((len == 1 228 && *name == '.') 229 || (flags & ISDOTDOT)) { 230 if (namelen == 1 231 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 232 /* 233 * Save directory entry's inode number and 234 * release directory buffer. 235 */ 236 dp->i_ino = isodirino(ep, imp); 237 goto found; 238 } 239 if (namelen != 1 240 || ep->name[0] != 0) 241 goto notfound; 242 } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) { 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 file system 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, p); /* race to get the inode */ 355 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, 356 dp->i_ino != ino, ep); 357 brelse(bp); 358 if (error) { 359 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 360 return (error); 361 } 362 if (lockparent && (flags & ISLASTCN)) { 363 if ((error = vn_lock(pdp, LK_EXCLUSIVE, p)) != 0) { 364 cnp->cn_flags |= PDIRUNLOCK; 365 vput(tdp); 366 return (error); 367 } 368 } else 369 cnp->cn_flags |= PDIRUNLOCK; 370 *vpp = tdp; 371 } else if (dp->i_number == dp->i_ino) { 372 brelse(bp); 373 VREF(vdp); /* we want ourself, ie "." */ 374 *vpp = vdp; 375 } else { 376 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, 377 dp->i_ino != ino, ep); 378 brelse(bp); 379 if (error) 380 return (error); 381 if (!lockparent || !(flags & ISLASTCN)) { 382 cnp->cn_flags |= PDIRUNLOCK; 383 VOP_UNLOCK(pdp, 0, p); 384 } 385 *vpp = tdp; 386 } 387 388 /* 389 * Insert name into cache if appropriate. 390 */ 391 if (cnp->cn_flags & MAKEENTRY) 392 cache_enter(vdp, *vpp, cnp); 393 return (0); 394 } 395 396 /* 397 * Return buffer with the contents of block "offset" from the beginning of 398 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 399 * remaining space in the directory. 400 */ 401 int 402 cd9660_blkatoff(vp, offset, res, bpp) 403 struct vnode *vp; 404 off_t offset; 405 char **res; 406 struct buf **bpp; 407 { 408 struct iso_node *ip; 409 register struct iso_mnt *imp; 410 struct buf *bp; 411 daddr_t lbn; 412 int bsize, error; 413 414 ip = VTOI(vp); 415 imp = ip->i_mnt; 416 lbn = lblkno(imp, offset); 417 bsize = blksize(imp, ip, lbn); 418 419 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 420 brelse(bp); 421 *bpp = NULL; 422 return (error); 423 } 424 425 /* 426 * We must BMAP the buffer because the directory code may use b_blkno 427 * to calculate the inode for certain types of directory entries. 428 * We could get away with not doing it before we VMIO-backed the 429 * directories because the buffers would get freed atomically with 430 * the invalidation of their data. But with VMIO-backed buffers 431 * the buffers may be freed and then later reconstituted - and the 432 * reconstituted buffer will have no knowledge of b_blkno. 433 */ 434 if (bp->b_blkno == bp->b_lblkno) { 435 error = VOP_BMAP(vp, bp->b_lblkno, NULL, 436 &bp->b_blkno, NULL, NULL); 437 if (error) { 438 bp->b_error = error; 439 bp->b_flags |= B_ERROR; 440 brelse(bp); 441 *bpp = NULL; 442 return (error); 443 } 444 } 445 446 if (res) 447 *res = (char *)bp->b_data + blkoff(imp, offset); 448 *bpp = bp; 449 return (0); 450 } 451