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 1.25 2008/06/19 23:27:39 dillon 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 "iso.h" 54 #include "cd9660_node.h" 55 #include "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 * cd9660_lookup(struct vnode *a_dvp, struct vnode **a_vpp, 90 * struct componentname *a_cnp) 91 */ 92 int 93 cd9660_lookup(struct vop_old_lookup_args *ap) 94 { 95 struct vnode *vdp; /* vnode for directory being searched */ 96 globaldata_t gd = mycpu; 97 struct iso_node *dp; /* inode for directory being searched */ 98 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; 123 124 bp = NULL; 125 *vpp = NULL; 126 vdp = ap->a_dvp; 127 dp = VTOI(vdp); 128 imp = dp->i_mnt; 129 lockparent = flags & CNP_LOCKPARENT; 130 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT); 131 cnp->cn_flags &= ~CNP_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 != NAMEI_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_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp))) 169 return (error); 170 numdirpasses = 2; 171 gd->gd_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_devblkatoff(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 & CNP_ISDOTDOT)) { 229 if (namelen == 1 230 && ep->name[0] == ((flags & CNP_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, 242 ep->name, namelen, 243 imp->joliet_level, 244 imp->im_flags, 245 imp->im_d2l, 246 imp->im_l2d))) { 247 if (isoflags & 2) 248 ino = isodirino(ep, imp); 249 else 250 ino = bp->b_bio1.bio_offset + 251 entryoffsetinblock; 252 saveoffset = dp->i_offset; 253 } else if (ino) 254 goto foundino; 255 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 256 else if (res < 0) 257 goto notfound; 258 else if (res > 0 && numdirpasses == 2) 259 numdirpasses++; 260 #endif 261 } 262 break; 263 case ISO_FTYPE_RRIP: 264 if (isonum_711(ep->flags)&2) 265 ino = isodirino(ep, imp); 266 else 267 ino = bp->b_bio1.bio_offset + 268 entryoffsetinblock; 269 dp->i_ino = ino; 270 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); 271 if (namelen == cnp->cn_namelen 272 && !bcmp(name,altname,namelen)) 273 goto found; 274 ino = 0; 275 break; 276 } 277 dp->i_offset += reclen; 278 entryoffsetinblock += reclen; 279 } 280 if (ino) { 281 foundino: 282 dp->i_ino = ino; 283 if (saveoffset != dp->i_offset) { 284 if (lblkno(imp, dp->i_offset) != 285 lblkno(imp, saveoffset)) { 286 if (bp != NULL) 287 brelse(bp); 288 if ((error = cd9660_devblkatoff(vdp, 289 (off_t)saveoffset, NULL, &bp)) != 0) 290 return (error); 291 } 292 entryoffsetinblock = saveoffset & bmask; 293 ep = (struct iso_directory_record *) 294 ((char *)bp->b_data + entryoffsetinblock); 295 dp->i_offset = saveoffset; 296 } 297 goto found; 298 } 299 notfound: 300 /* 301 * If we started in the middle of the directory and failed 302 * to find our target, we must check the beginning as well. 303 */ 304 if (numdirpasses == 2) { 305 numdirpasses--; 306 dp->i_offset = 0; 307 endsearch = dp->i_diroff; 308 goto searchloop; 309 } 310 if (bp != NULL) 311 brelse(bp); 312 313 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) 314 return (EROFS); 315 return (ENOENT); 316 317 found: 318 if (numdirpasses == 2) 319 gd->gd_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 (nameiop == NAMEI_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 & CNP_ISDOTDOT) { 354 vn_unlock(pdp); /* 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); 360 return (error); 361 } 362 if (lockparent) { 363 if ((error = vn_lock(pdp, LK_EXCLUSIVE)) != 0) { 364 cnp->cn_flags |= CNP_PDIRUNLOCK; 365 vput(tdp); 366 return (error); 367 } 368 } else 369 cnp->cn_flags |= CNP_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) { 382 cnp->cn_flags |= CNP_PDIRUNLOCK; 383 vn_unlock(pdp); 384 } 385 *vpp = tdp; 386 } 387 return (0); 388 } 389 390 /* 391 * Return a buffer with the contents of block "offset" from the beginning of 392 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 393 * remaining space in the directory. 394 */ 395 int 396 cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 397 { 398 struct iso_node *ip; 399 struct iso_mnt *imp; 400 struct buf *bp; 401 daddr_t lbn; 402 int bsize, error; 403 404 ip = VTOI(vp); 405 imp = ip->i_mnt; 406 lbn = lblkno(imp, offset); 407 bsize = blksize(imp, ip, lbn); 408 409 if ((error = bread(vp, lblktooff(imp, lbn), bsize, &bp)) != 0) { 410 brelse(bp); 411 *bpp = NULL; 412 return (error); 413 } 414 415 /* 416 * We must BMAP the buffer because the directory code may use 417 * bio_offset to calculate the inode for certain types of directory 418 * entries. We could get away with not doing it before we 419 * VMIO-backed the directories because the buffers would get freed 420 * atomically with the invalidation of their data. But with 421 * VMIO-backed buffers the buffers may be freed and then later 422 * reconstituted - and the reconstituted buffer will have no 423 * knowledge of bio_offset. 424 */ 425 if (bp->b_bio2.bio_offset == NOOFFSET) { 426 error = VOP_BMAP(vp, bp->b_bio1.bio_offset, 427 &bp->b_bio2.bio_offset, NULL, NULL, 428 BUF_CMD_READ); 429 if (error) { 430 bp->b_error = error; 431 bp->b_flags |= B_ERROR; 432 brelse(bp); 433 *bpp = NULL; 434 return (error); 435 } 436 } 437 438 if (res) 439 *res = (char *)bp->b_data + blkoff(imp, offset); 440 *bpp = bp; 441 return (0); 442 } 443 444 445 /* 446 * Return a buffer with the contents of block "offset" from the beginning of 447 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 448 * remaining space in the directory. 449 * 450 * Use the underlying device vnode rather then the passed vnode for the 451 * buffer cache operation. This allows us to access meta-data conveniently 452 * without having to instantiate a VM object for the vnode. 453 * 454 * WARNING! Callers of this routine need to be careful when accessing 455 * the bio_offset. Since this is a device buffer, the device offset will 456 * be in bio1.bio_offset, not bio2.bio_offset. 457 */ 458 int 459 cd9660_devblkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 460 { 461 struct iso_node *ip; 462 struct iso_mnt *imp; 463 struct buf *bp; 464 daddr_t lbn; 465 off_t doffset; 466 int bsize, error; 467 468 ip = VTOI(vp); 469 imp = ip->i_mnt; 470 lbn = lblkno(imp, offset); 471 bsize = blksize(imp, ip, lbn); 472 473 error = VOP_BMAP(vp, lblktooff(imp, lbn), &doffset, NULL, NULL, 474 BUF_CMD_READ); 475 if (error) 476 return (error); 477 478 if ((error = bread(imp->im_devvp, doffset, bsize, &bp)) != 0) { 479 brelse(bp); 480 *bpp = NULL; 481 return (error); 482 } 483 if (res) 484 *res = (char *)bp->b_data + blkoff(imp, offset); 485 *bpp = bp; 486 return (0); 487 } 488 489