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 * @(#)cd9660_lookup.c 8.2 (Berkeley) 1/23/94 40 */ 41 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/namei.h> 48 #include <sys/bio.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 filesystem 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 register struct vnode *vdp; /* vnode for directory being searched */ 98 register struct iso_node *dp; /* inode for directory being searched */ 99 register struct iso_mnt *imp; /* filesystem 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 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 thread *td = cnp->cn_thread; 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 cnp->cn_flags &= ~PDIRUNLOCK; 132 133 /* 134 * We now have a segment name to search for, and a directory to search. 135 */ 136 137 len = cnp->cn_namelen; 138 name = cnp->cn_nameptr; 139 /* 140 * A leading `=' means, we are looking for an associated file 141 */ 142 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) 143 { 144 len--; 145 name++; 146 } 147 148 /* 149 * If there is cached information on a previous search of 150 * this directory, pick up where we last left off. 151 * We cache only lookups as these are the most common 152 * and have the greatest payoff. Caching CREATE has little 153 * benefit as it usually must search the entire directory 154 * to determine that the entry does not exist. Caching the 155 * location of the last DELETE or RENAME has not reduced 156 * profiling time and hence has been removed in the interest 157 * of simplicity. 158 */ 159 bmask = imp->im_bmask; 160 if (nameiop != LOOKUP || dp->i_diroff == 0 || 161 dp->i_diroff > dp->i_size) { 162 entryoffsetinblock = 0; 163 dp->i_offset = 0; 164 numdirpasses = 1; 165 } else { 166 dp->i_offset = dp->i_diroff; 167 if ((entryoffsetinblock = dp->i_offset & bmask) && 168 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp))) 169 return (error); 170 numdirpasses = 2; 171 nchstats.ncs_2passes++; 172 } 173 endsearch = dp->i_size; 174 175 searchloop: 176 while (dp->i_offset < endsearch) { 177 /* 178 * If offset is on a block boundary, 179 * read the next directory block. 180 * Release previous if it exists. 181 */ 182 if ((dp->i_offset & bmask) == 0) { 183 if (bp != NULL) 184 brelse(bp); 185 if ((error = 186 cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0) 187 return (error); 188 entryoffsetinblock = 0; 189 } 190 /* 191 * Get pointer to next entry. 192 */ 193 ep = (struct iso_directory_record *) 194 ((char *)bp->b_data + entryoffsetinblock); 195 196 reclen = isonum_711(ep->length); 197 if (reclen == 0) { 198 /* skip to next block, if any */ 199 dp->i_offset = 200 (dp->i_offset & ~bmask) + imp->logical_block_size; 201 continue; 202 } 203 204 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 205 /* illegal entry, stop */ 206 break; 207 208 if (entryoffsetinblock + reclen > imp->logical_block_size) 209 /* entries are not allowed to cross boundaries */ 210 break; 211 212 namelen = isonum_711(ep->name_len); 213 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 214 &ep->date[6]: ep->flags); 215 216 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 217 /* illegal entry, stop */ 218 break; 219 220 /* 221 * Check for a name match. 222 */ 223 switch (imp->iso_ftype) { 224 default: 225 if (!(isoflags & 4) == !assoc) { 226 if ((len == 1 227 && *name == '.') 228 || (flags & ISDOTDOT)) { 229 if (namelen == 1 230 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 231 /* 232 * Save directory entry's inode number and 233 * release directory buffer. 234 */ 235 dp->i_ino = isodirino(ep, imp); 236 goto found; 237 } 238 if (namelen != 1 239 || ep->name[0] != 0) 240 goto notfound; 241 } else if (!(res = isofncmp(name, len, ep->name, namelen, imp->joliet_level))) { 242 if (isoflags & 2) 243 ino = isodirino(ep, imp); 244 else 245 ino = dbtob(bp->b_blkno) 246 + entryoffsetinblock; 247 saveoffset = dp->i_offset; 248 } else if (ino) 249 goto foundino; 250 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 251 else if (res < 0) 252 goto notfound; 253 else if (res > 0 && numdirpasses == 2) 254 numdirpasses++; 255 #endif 256 } 257 break; 258 case ISO_FTYPE_RRIP: 259 if (isonum_711(ep->flags)&2) 260 ino = isodirino(ep, imp); 261 else 262 ino = dbtob(bp->b_blkno) + entryoffsetinblock; 263 dp->i_ino = ino; 264 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); 265 if (namelen == cnp->cn_namelen 266 && !bcmp(name,altname,namelen)) 267 goto found; 268 ino = 0; 269 break; 270 } 271 dp->i_offset += reclen; 272 entryoffsetinblock += reclen; 273 } 274 if (ino) { 275 foundino: 276 dp->i_ino = ino; 277 if (saveoffset != dp->i_offset) { 278 if (lblkno(imp, dp->i_offset) != 279 lblkno(imp, saveoffset)) { 280 if (bp != NULL) 281 brelse(bp); 282 if ((error = cd9660_blkatoff(vdp, 283 (off_t)saveoffset, NULL, &bp)) != 0) 284 return (error); 285 } 286 entryoffsetinblock = saveoffset & bmask; 287 ep = (struct iso_directory_record *) 288 ((char *)bp->b_data + entryoffsetinblock); 289 dp->i_offset = saveoffset; 290 } 291 goto found; 292 } 293 notfound: 294 /* 295 * If we started in the middle of the directory and failed 296 * to find our target, we must check the beginning as well. 297 */ 298 if (numdirpasses == 2) { 299 numdirpasses--; 300 dp->i_offset = 0; 301 endsearch = dp->i_diroff; 302 goto searchloop; 303 } 304 if (bp != NULL) 305 brelse(bp); 306 307 /* 308 * Insert name into cache (as non-existent) if appropriate. 309 */ 310 if (cnp->cn_flags & MAKEENTRY) 311 cache_enter(vdp, *vpp, cnp); 312 if (nameiop == CREATE || nameiop == RENAME) 313 return (EROFS); 314 return (ENOENT); 315 316 found: 317 if (numdirpasses == 2) 318 nchstats.ncs_pass2++; 319 320 /* 321 * Found component in pathname. 322 * If the final component of path name, save information 323 * in the cache as to where the entry was found. 324 */ 325 if ((flags & ISLASTCN) && nameiop == LOOKUP) 326 dp->i_diroff = dp->i_offset; 327 328 /* 329 * Step through the translation in the name. We do not `iput' the 330 * directory because we may need it again if a symbolic link 331 * is relative to the current directory. Instead we save it 332 * unlocked as "pdp". We must get the target inode before unlocking 333 * the directory to insure that the inode will not be removed 334 * before we get it. We prevent deadlock by always fetching 335 * inodes from the root, moving down the directory tree. Thus 336 * when following backward pointers ".." we must unlock the 337 * parent directory before getting the requested directory. 338 * There is a potential race condition here if both the current 339 * and parent directories are removed before the `iget' for the 340 * inode associated with ".." returns. We hope that this occurs 341 * infrequently since we cannot avoid this race condition without 342 * implementing a sophisticated deadlock detection algorithm. 343 * Note also that this simple deadlock detection scheme will not 344 * work if the filesystem has any hard links other than ".." 345 * that point backwards in the directory structure. 346 */ 347 pdp = vdp; 348 /* 349 * If ino is different from dp->i_ino, 350 * it's a relocated directory. 351 */ 352 if (flags & ISDOTDOT) { 353 VOP_UNLOCK(pdp, 0, td); /* race to get the inode */ 354 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, 355 LK_EXCLUSIVE, &tdp, 356 dp->i_ino != ino, ep); 357 brelse(bp); 358 if (error) { 359 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td); 360 return (error); 361 } 362 if (lockparent && (flags & ISLASTCN)) { 363 if ((error = vn_lock(pdp, LK_EXCLUSIVE, td)) != 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, 377 LK_EXCLUSIVE, &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 register struct iso_mnt *imp; 411 struct buf *bp; 412 daddr_t lbn; 413 int bsize, bshift, error; 414 415 ip = VTOI(vp); 416 imp = ip->i_mnt; 417 lbn = lblkno(imp, offset); 418 bsize = blksize(imp, ip, lbn); 419 bshift = imp->im_bshift; 420 421 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 422 brelse(bp); 423 *bpp = NULL; 424 return (error); 425 } 426 427 /* 428 * We must BMAP the buffer because the directory code may use b_blkno 429 * to calculate the inode for certain types of directory entries. 430 * We could get away with not doing it before we VMIO-backed the 431 * directories because the buffers would get freed atomically with 432 * the invalidation of their data. But with VMIO-backed buffers 433 * the buffers may be freed and then later reconstituted - and the 434 * reconstituted buffer will have no knowledge of b_blkno. 435 */ 436 if (bp->b_blkno == bp->b_lblkno) { 437 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT); 438 } 439 440 if (res) 441 *res = (char *)bp->b_data + blkoff(imp, offset); 442 *bpp = bp; 443 return (0); 444 } 445