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 <fs/cd9660/iso.h> 50 #include <fs/cd9660/cd9660_node.h> 51 #include <fs/cd9660/iso_rrip.h> 52 53 struct cd9660_ino_alloc_arg { 54 ino_t ino; 55 ino_t i_ino; 56 struct iso_directory_record *ep; 57 }; 58 59 static int 60 cd9660_ino_alloc(struct mount *mp, void *arg, int lkflags, 61 struct vnode **vpp) 62 { 63 struct cd9660_ino_alloc_arg *dd_arg; 64 65 dd_arg = arg; 66 return (cd9660_vget_internal(mp, dd_arg->i_ino, lkflags, vpp, 67 dd_arg->i_ino != dd_arg->ino, dd_arg->ep)); 68 } 69 70 /* 71 * Convert a component of a pathname into a pointer to a locked inode. 72 * This is a very central and rather complicated routine. 73 * If the filesystem is not maintained in a strict tree hierarchy, 74 * this can result in a deadlock situation (see comments in code below). 75 * 76 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 77 * whether the name is to be looked up, created, renamed, or deleted. 78 * When CREATE, RENAME, or DELETE is specified, information usable in 79 * creating, renaming, or deleting a directory entry may be calculated. 80 * If flag has LOCKPARENT or'ed into it and the target of the pathname 81 * exists, lookup returns both the target and its parent directory locked. 82 * When creating or renaming and LOCKPARENT is specified, the target may 83 * not be ".". When deleting and LOCKPARENT is specified, the target may 84 * be "."., but the caller must check to ensure it does an vrele and iput 85 * instead of two iputs. 86 * 87 * Overall outline of ufs_lookup: 88 * 89 * search for name in directory, to found or notfound 90 * notfound: 91 * if creating, return locked directory, leaving info on available slots 92 * else return error 93 * found: 94 * if at end of path and deleting, return information to allow delete 95 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 96 * inode and return info to allow rewrite 97 * if not at end, add name to cache; if at end and neither creating 98 * nor deleting, add name to cache 99 * 100 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. 101 */ 102 int 103 cd9660_lookup(ap) 104 struct vop_cachedlookup_args /* { 105 struct vnode *a_dvp; 106 struct vnode **a_vpp; 107 struct componentname *a_cnp; 108 } */ *ap; 109 { 110 struct vnode *vdp; /* vnode for directory being searched */ 111 struct iso_node *dp; /* inode for directory being searched */ 112 struct iso_mnt *imp; /* filesystem that directory is in */ 113 struct buf *bp; /* a buffer of directory entries */ 114 struct iso_directory_record *ep;/* the current directory entry */ 115 struct iso_directory_record *ep2;/* copy of current directory entry */ 116 int entryoffsetinblock; /* offset of ep in bp's buffer */ 117 int saveoffset = 0; /* offset of last directory entry in dir */ 118 doff_t i_diroff; /* cached i_diroff value. */ 119 doff_t i_offset; /* cached i_offset value. */ 120 int numdirpasses; /* strategy for directory search */ 121 doff_t endsearch; /* offset to end directory search */ 122 struct vnode *pdp; /* saved dp during symlink work */ 123 struct vnode *tdp; /* returned by cd9660_vget_internal */ 124 struct cd9660_ino_alloc_arg dd_arg; 125 u_long bmask; /* block offset mask */ 126 int error; 127 ino_t ino, i_ino; 128 int ltype, reclen; 129 u_short namelen; 130 int isoflags; 131 char altname[NAME_MAX]; 132 int res; 133 int assoc, len; 134 char *name; 135 struct vnode **vpp = ap->a_vpp; 136 struct componentname *cnp = ap->a_cnp; 137 int flags = cnp->cn_flags; 138 int nameiop = cnp->cn_nameiop; 139 140 ep2 = ep = NULL; 141 bp = NULL; 142 *vpp = NULL; 143 vdp = ap->a_dvp; 144 dp = VTOI(vdp); 145 imp = dp->i_mnt; 146 147 /* 148 * We now have a segment name to search for, and a directory to search. 149 */ 150 ino = reclen = 0; 151 i_diroff = dp->i_diroff; 152 len = cnp->cn_namelen; 153 name = cnp->cn_nameptr; 154 155 /* 156 * A leading `=' means, we are looking for an associated file 157 */ 158 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) 159 { 160 len--; 161 name++; 162 } 163 164 /* 165 * If there is cached information on a previous search of 166 * this directory, pick up where we last left off. 167 * We cache only lookups as these are the most common 168 * and have the greatest payoff. Caching CREATE has little 169 * benefit as it usually must search the entire directory 170 * to determine that the entry does not exist. Caching the 171 * location of the last DELETE or RENAME has not reduced 172 * profiling time and hence has been removed in the interest 173 * of simplicity. 174 */ 175 bmask = imp->im_bmask; 176 if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) { 177 entryoffsetinblock = 0; 178 i_offset = 0; 179 numdirpasses = 1; 180 } else { 181 i_offset = i_diroff; 182 if ((entryoffsetinblock = i_offset & bmask) && 183 (error = cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp))) 184 return (error); 185 numdirpasses = 2; 186 nchstats.ncs_2passes++; 187 } 188 endsearch = dp->i_size; 189 190 searchloop: 191 while (i_offset < endsearch) { 192 /* 193 * If offset is on a block boundary, 194 * read the next directory block. 195 * Release previous if it exists. 196 */ 197 if ((i_offset & bmask) == 0) { 198 if (bp != NULL) 199 brelse(bp); 200 if ((error = 201 cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)) != 0) 202 return (error); 203 entryoffsetinblock = 0; 204 } 205 /* 206 * Get pointer to next entry. 207 */ 208 ep = (struct iso_directory_record *) 209 ((char *)bp->b_data + entryoffsetinblock); 210 211 reclen = isonum_711(ep->length); 212 if (reclen == 0) { 213 /* skip to next block, if any */ 214 i_offset = 215 (i_offset & ~bmask) + imp->logical_block_size; 216 continue; 217 } 218 219 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 220 /* illegal entry, stop */ 221 break; 222 223 if (entryoffsetinblock + reclen > imp->logical_block_size) 224 /* entries are not allowed to cross boundaries */ 225 break; 226 227 namelen = isonum_711(ep->name_len); 228 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 229 &ep->date[6]: ep->flags); 230 231 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 232 /* illegal entry, stop */ 233 break; 234 235 /* 236 * Check for a name match. 237 */ 238 switch (imp->iso_ftype) { 239 default: 240 if (!(isoflags & 4) == !assoc) { 241 if ((len == 1 242 && *name == '.') 243 || (flags & ISDOTDOT)) { 244 if (namelen == 1 245 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 246 /* 247 * Save directory entry's inode number and 248 * release directory buffer. 249 */ 250 i_ino = isodirino(ep, imp); 251 goto found; 252 } 253 if (namelen != 1 254 || ep->name[0] != 0) 255 goto notfound; 256 } else if (!(res = isofncmp(name, len, 257 ep->name, namelen, 258 imp->joliet_level, 259 imp->im_flags, 260 imp->im_d2l, 261 imp->im_l2d))) { 262 if (isoflags & 2) 263 ino = isodirino(ep, imp); 264 else 265 ino = dbtob(bp->b_blkno) 266 + entryoffsetinblock; 267 saveoffset = i_offset; 268 } else if (ino) 269 goto foundino; 270 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 271 else if (res < 0) 272 goto notfound; 273 else if (res > 0 && numdirpasses == 2) 274 numdirpasses++; 275 #endif 276 } 277 break; 278 case ISO_FTYPE_RRIP: 279 if (isonum_711(ep->flags)&2) 280 ino = isodirino(ep, imp); 281 else 282 ino = dbtob(bp->b_blkno) + entryoffsetinblock; 283 i_ino = ino; 284 cd9660_rrip_getname(ep, altname, &namelen, &i_ino, imp); 285 if (namelen == cnp->cn_namelen 286 && !bcmp(name,altname,namelen)) 287 goto found; 288 ino = 0; 289 break; 290 } 291 i_offset += reclen; 292 entryoffsetinblock += reclen; 293 } 294 if (ino) { 295 foundino: 296 i_ino = ino; 297 if (saveoffset != i_offset) { 298 if (lblkno(imp, i_offset) != 299 lblkno(imp, saveoffset)) { 300 if (bp != NULL) 301 brelse(bp); 302 if ((error = cd9660_blkatoff(vdp, 303 (off_t)saveoffset, NULL, &bp)) != 0) 304 return (error); 305 } 306 entryoffsetinblock = saveoffset & bmask; 307 ep = (struct iso_directory_record *) 308 ((char *)bp->b_data + entryoffsetinblock); 309 reclen = isonum_711(ep->length); 310 i_offset = saveoffset; 311 } 312 goto found; 313 } 314 notfound: 315 /* 316 * If we started in the middle of the directory and failed 317 * to find our target, we must check the beginning as well. 318 */ 319 if (numdirpasses == 2) { 320 numdirpasses--; 321 i_offset = 0; 322 endsearch = i_diroff; 323 goto searchloop; 324 } 325 if (bp != NULL) 326 brelse(bp); 327 328 /* 329 * Insert name into cache (as non-existent) if appropriate. 330 */ 331 if (cnp->cn_flags & MAKEENTRY) 332 cache_enter(vdp, *vpp, cnp); 333 if (nameiop == CREATE || nameiop == RENAME) 334 return (EROFS); 335 return (ENOENT); 336 337 found: 338 if (numdirpasses == 2) 339 nchstats.ncs_pass2++; 340 341 /* 342 * Found component in pathname. 343 * If the final component of path name, save information 344 * in the cache as to where the entry was found. 345 */ 346 if ((flags & ISLASTCN) && nameiop == LOOKUP) 347 dp->i_diroff = i_offset; 348 349 /* 350 * Step through the translation in the name. We do not `vput' the 351 * directory because we may need it again if a symbolic link 352 * is relative to the current directory. Instead we save it 353 * unlocked as "pdp". We must get the target inode before unlocking 354 * the directory to insure that the inode will not be removed 355 * before we get it. We prevent deadlock by always fetching 356 * inodes from the root, moving down the directory tree. Thus 357 * when following backward pointers ".." we must unlock the 358 * parent directory before getting the requested directory. 359 * There is a potential race condition here if both the current 360 * and parent directories are removed before the `vget' for the 361 * inode associated with ".." returns. We hope that this occurs 362 * infrequently since we cannot avoid this race condition without 363 * implementing a sophisticated deadlock detection algorithm. 364 * Note also that this simple deadlock detection scheme will not 365 * work if the filesystem has any hard links other than ".." 366 * that point backwards in the directory structure. 367 */ 368 pdp = vdp; 369 370 /* 371 * Make a copy of the directory entry for non "." lookups so 372 * we can drop the buffer before calling vget() to avoid a 373 * lock order reversal between the vnode lock and the buffer 374 * lock. 375 */ 376 if (dp->i_number != i_ino) { 377 ep2 = malloc(reclen, M_TEMP, M_WAITOK); 378 bcopy(ep, ep2, reclen); 379 ep = ep2; 380 } 381 brelse(bp); 382 383 /* 384 * If ino is different from i_ino, 385 * it's a relocated directory. 386 */ 387 if (flags & ISDOTDOT) { 388 dd_arg.ino = ino; 389 dd_arg.i_ino = i_ino; 390 dd_arg.ep = ep; 391 error = vn_vget_ino_gen(pdp, cd9660_ino_alloc, &dd_arg, 392 cnp->cn_lkflags, &tdp); 393 free(ep2, M_TEMP); 394 if (error != 0) 395 return (error); 396 *vpp = tdp; 397 } else if (dp->i_number == i_ino) { 398 VREF(vdp); /* we want ourself, ie "." */ 399 /* 400 * When we lookup "." we still can be asked to lock it 401 * differently. 402 */ 403 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 404 if (ltype != VOP_ISLOCKED(vdp)) { 405 if (ltype == LK_EXCLUSIVE) 406 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 407 else /* if (ltype == LK_SHARED) */ 408 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 409 } 410 *vpp = vdp; 411 } else { 412 error = cd9660_vget_internal(vdp->v_mount, i_ino, 413 cnp->cn_lkflags, &tdp, 414 i_ino != ino, ep); 415 free(ep2, M_TEMP); 416 if (error) 417 return (error); 418 *vpp = tdp; 419 } 420 421 /* 422 * Insert name into cache if appropriate. 423 */ 424 if (cnp->cn_flags & MAKEENTRY) 425 cache_enter(vdp, *vpp, cnp); 426 return (0); 427 } 428 429 /* 430 * Return buffer with the contents of block "offset" from the beginning of 431 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 432 * remaining space in the directory. 433 */ 434 int 435 cd9660_blkatoff(vp, offset, res, bpp) 436 struct vnode *vp; 437 off_t offset; 438 char **res; 439 struct buf **bpp; 440 { 441 struct iso_node *ip; 442 struct iso_mnt *imp; 443 struct buf *bp; 444 daddr_t lbn; 445 int bsize, bshift, error; 446 447 ip = VTOI(vp); 448 imp = ip->i_mnt; 449 lbn = lblkno(imp, offset); 450 bsize = blksize(imp, ip, lbn); 451 bshift = imp->im_bshift; 452 453 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 454 brelse(bp); 455 *bpp = NULL; 456 return (error); 457 } 458 459 /* 460 * We must BMAP the buffer because the directory code may use b_blkno 461 * to calculate the inode for certain types of directory entries. 462 * We could get away with not doing it before we VMIO-backed the 463 * directories because the buffers would get freed atomically with 464 * the invalidation of their data. But with VMIO-backed buffers 465 * the buffers may be freed and then later reconstituted - and the 466 * reconstituted buffer will have no knowledge of b_blkno. 467 */ 468 if (bp->b_blkno == bp->b_lblkno) { 469 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT); 470 } 471 472 if (res) 473 *res = (char *)bp->b_data + blkoff(imp, offset); 474 *bpp = bp; 475 return (0); 476 } 477