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 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/namei.h> 48 #include <sys/buf.h> 49 #include <sys/vnode.h> 50 #include <sys/mount.h> 51 52 #include "iso.h" 53 #include "cd9660_node.h" 54 #include "iso_rrip.h" 55 56 #include <sys/buf2.h> 57 58 /* 59 * Convert a component of a pathname into a pointer to a locked inode. 60 * This is a very central and rather complicated routine. 61 * If the file system is not maintained in a strict tree hierarchy, 62 * this can result in a deadlock situation (see comments in code below). 63 * 64 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 65 * whether the name is to be looked up, created, renamed, or deleted. 66 * When CREATE, RENAME, or DELETE is specified, information usable in 67 * creating, renaming, or deleting a directory entry may be calculated. 68 * If flag has LOCKPARENT or'ed into it and the target of the pathname 69 * exists, lookup returns both the target and its parent directory locked. 70 * When creating or renaming and LOCKPARENT is specified, the target may 71 * not be ".". When deleting and LOCKPARENT is specified, the target may 72 * be "."., but the caller must check to ensure it does an vrele and iput 73 * instead of two iputs. 74 * 75 * Overall outline of ufs_lookup: 76 * 77 * search for name in directory, to found or notfound 78 * notfound: 79 * if creating, return locked directory, leaving info on available slots 80 * else return error 81 * found: 82 * if at end of path and deleting, return information to allow delete 83 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 84 * inode and return info to allow rewrite 85 * if not at end, add name to cache; if at end and neither creating 86 * nor deleting, add name to cache 87 * 88 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. 89 * 90 * cd9660_lookup(struct vnode *a_dvp, struct vnode **a_vpp, 91 * struct componentname *a_cnp) 92 */ 93 int 94 cd9660_lookup(struct vop_old_lookup_args *ap) 95 { 96 struct vnode *vdp; /* vnode for directory being searched */ 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 = NULL;/* 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 } 172 endsearch = dp->i_size; 173 174 searchloop: 175 while (dp->i_offset < endsearch) { 176 /* 177 * If offset is on a block boundary, 178 * read the next directory block. 179 * Release previous if it exists. 180 */ 181 if ((dp->i_offset & bmask) == 0) { 182 if (bp != NULL) 183 brelse(bp); 184 if ((error = 185 cd9660_devblkatoff(vdp, (off_t)dp->i_offset, NULL, &bp)) != 0) 186 return (error); 187 entryoffsetinblock = 0; 188 } 189 /* 190 * Get pointer to next entry. 191 */ 192 ep = (struct iso_directory_record *) 193 ((char *)bp->b_data + entryoffsetinblock); 194 195 reclen = isonum_711(ep->length); 196 if (reclen == 0) { 197 /* skip to next block, if any */ 198 dp->i_offset = 199 (dp->i_offset & ~bmask) + imp->logical_block_size; 200 continue; 201 } 202 203 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 204 /* illegal entry, stop */ 205 break; 206 207 if (entryoffsetinblock + reclen > imp->logical_block_size) 208 /* entries are not allowed to cross boundaries */ 209 break; 210 211 namelen = isonum_711(ep->name_len); 212 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 213 &ep->date[6]: ep->flags); 214 215 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 216 /* illegal entry, stop */ 217 break; 218 219 /* 220 * Check for a name match. 221 */ 222 switch (imp->iso_ftype) { 223 default: 224 if (!(isoflags & 4) == !assoc) { 225 if ((len == 1 226 && *name == '.') 227 || (flags & CNP_ISDOTDOT)) { 228 if (namelen == 1 229 && ep->name[0] == ((flags & CNP_ISDOTDOT) ? 1 : 0)) { 230 /* 231 * Save directory entry's inode number and 232 * release directory buffer. 233 */ 234 dp->i_ino = isodirino(ep, imp); 235 goto found; 236 } 237 if (namelen != 1 238 || ep->name[0] != 0) 239 goto notfound; 240 } else if (!(res = isofncmp(name, len, 241 ep->name, namelen, 242 imp->joliet_level, 243 imp->im_flags, 244 imp->im_d2l, 245 imp->im_l2d))) { 246 if (isoflags & 2) 247 ino = isodirino(ep, imp); 248 else 249 ino = bp->b_bio1.bio_offset + 250 entryoffsetinblock; 251 saveoffset = dp->i_offset; 252 } else if (ino) 253 goto foundino; 254 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 255 else if (res < 0) 256 goto notfound; 257 else if (res > 0 && numdirpasses == 2) 258 numdirpasses++; 259 #endif 260 } 261 break; 262 case ISO_FTYPE_RRIP: 263 if (isonum_711(ep->flags)&2) 264 ino = isodirino(ep, imp); 265 else 266 ino = bp->b_bio1.bio_offset + 267 entryoffsetinblock; 268 dp->i_ino = ino; 269 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); 270 if (namelen == cnp->cn_namelen 271 && !bcmp(name,altname,namelen)) 272 goto found; 273 ino = 0; 274 break; 275 } 276 dp->i_offset += reclen; 277 entryoffsetinblock += reclen; 278 } 279 if (ino) { 280 foundino: 281 dp->i_ino = ino; 282 if (saveoffset != dp->i_offset) { 283 if (lblkno(imp, dp->i_offset) != 284 lblkno(imp, saveoffset)) { 285 if (bp != NULL) 286 brelse(bp); 287 if ((error = cd9660_devblkatoff(vdp, 288 (off_t)saveoffset, NULL, &bp)) != 0) 289 return (error); 290 } 291 entryoffsetinblock = saveoffset & bmask; 292 ep = (struct iso_directory_record *) 293 ((char *)bp->b_data + entryoffsetinblock); 294 dp->i_offset = saveoffset; 295 } 296 goto found; 297 } 298 notfound: 299 /* 300 * If we started in the middle of the directory and failed 301 * to find our target, we must check the beginning as well. 302 */ 303 if (numdirpasses == 2) { 304 numdirpasses--; 305 dp->i_offset = 0; 306 endsearch = dp->i_diroff; 307 goto searchloop; 308 } 309 if (bp != NULL) 310 brelse(bp); 311 312 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) 313 return (EROFS); 314 return (ENOENT); 315 316 found: 317 /* 318 * Found component in pathname. 319 * If the final component of path name, save information 320 * in the cache as to where the entry was found. 321 */ 322 if (nameiop == NAMEI_LOOKUP) 323 dp->i_diroff = dp->i_offset; 324 325 /* 326 * Step through the translation in the name. We do not `iput' the 327 * directory because we may need it again if a symbolic link 328 * is relative to the current directory. Instead we save it 329 * unlocked as "pdp". We must get the target inode before unlocking 330 * the directory to insure that the inode will not be removed 331 * before we get it. We prevent deadlock by always fetching 332 * inodes from the root, moving down the directory tree. Thus 333 * when following backward pointers ".." we must unlock the 334 * parent directory before getting the requested directory. 335 * There is a potential race condition here if both the current 336 * and parent directories are removed before the `iget' for the 337 * inode associated with ".." returns. We hope that this occurs 338 * infrequently since we cannot avoid this race condition without 339 * implementing a sophisticated deadlock detection algorithm. 340 * Note also that this simple deadlock detection scheme will not 341 * work if the file system has any hard links other than ".." 342 * that point backwards in the directory structure. 343 */ 344 pdp = vdp; 345 /* 346 * If ino is different from dp->i_ino, 347 * it's a relocated directory. 348 */ 349 if (flags & CNP_ISDOTDOT) { 350 vn_unlock(pdp); /* race to get the inode */ 351 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, 352 dp->i_ino != ino, ep); 353 brelse(bp); 354 if (error) { 355 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY); 356 return (error); 357 } 358 if (lockparent) { 359 if ((error = vn_lock(pdp, LK_EXCLUSIVE)) != 0) { 360 cnp->cn_flags |= CNP_PDIRUNLOCK; 361 vput(tdp); 362 return (error); 363 } 364 } else 365 cnp->cn_flags |= CNP_PDIRUNLOCK; 366 *vpp = tdp; 367 } else if (dp->i_number == dp->i_ino) { 368 brelse(bp); 369 vref(vdp); /* we want ourself, ie "." */ 370 *vpp = vdp; 371 } else { 372 error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, 373 dp->i_ino != ino, ep); 374 brelse(bp); 375 if (error) 376 return (error); 377 if (!lockparent) { 378 cnp->cn_flags |= CNP_PDIRUNLOCK; 379 vn_unlock(pdp); 380 } 381 *vpp = tdp; 382 } 383 return (0); 384 } 385 386 /* 387 * Return a buffer with the contents of block "offset" from the beginning of 388 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 389 * remaining space in the directory. 390 */ 391 int 392 cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 393 { 394 struct iso_node *ip; 395 struct iso_mnt *imp; 396 struct buf *bp; 397 daddr_t lbn; 398 int bsize, error; 399 400 ip = VTOI(vp); 401 imp = ip->i_mnt; 402 lbn = lblkno(imp, offset); 403 bsize = blksize(imp, ip, lbn); 404 405 if ((error = bread(vp, lblktooff(imp, lbn), bsize, &bp)) != 0) { 406 brelse(bp); 407 *bpp = NULL; 408 return (error); 409 } 410 411 /* 412 * We must BMAP the buffer because the directory code may use 413 * bio_offset to calculate the inode for certain types of directory 414 * entries. We could get away with not doing it before we 415 * VMIO-backed the directories because the buffers would get freed 416 * atomically with the invalidation of their data. But with 417 * VMIO-backed buffers the buffers may be freed and then later 418 * reconstituted - and the reconstituted buffer will have no 419 * knowledge of bio_offset. 420 */ 421 if (bp->b_bio2.bio_offset == NOOFFSET) { 422 error = VOP_BMAP(vp, bp->b_bio1.bio_offset, 423 &bp->b_bio2.bio_offset, NULL, NULL, 424 BUF_CMD_READ); 425 if (error) { 426 bp->b_error = error; 427 bp->b_flags |= B_ERROR; 428 brelse(bp); 429 *bpp = NULL; 430 return (error); 431 } 432 } 433 434 if (res) 435 *res = (char *)bp->b_data + blkoff(imp, offset); 436 *bpp = bp; 437 return (0); 438 } 439 440 441 /* 442 * Return a buffer with the contents of block "offset" from the beginning of 443 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 444 * remaining space in the directory. 445 * 446 * Use the underlying device vnode rather then the passed vnode for the 447 * buffer cache operation. This allows us to access meta-data conveniently 448 * without having to instantiate a VM object for the vnode. 449 * 450 * WARNING! Callers of this routine need to be careful when accessing 451 * the bio_offset. Since this is a device buffer, the device offset will 452 * be in bio1.bio_offset, not bio2.bio_offset. 453 */ 454 int 455 cd9660_devblkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 456 { 457 struct iso_node *ip; 458 struct iso_mnt *imp; 459 struct buf *bp; 460 daddr_t lbn; 461 off_t doffset; 462 int bsize, error; 463 464 ip = VTOI(vp); 465 imp = ip->i_mnt; 466 lbn = lblkno(imp, offset); 467 bsize = blksize(imp, ip, lbn); 468 469 error = VOP_BMAP(vp, lblktooff(imp, lbn), &doffset, NULL, NULL, 470 BUF_CMD_READ); 471 if (error) 472 return (error); 473 474 if ((error = bread(imp->im_devvp, doffset, bsize, &bp)) != 0) { 475 brelse(bp); 476 *bpp = NULL; 477 return (error); 478 } 479 if (res) 480 *res = (char *)bp->b_data + blkoff(imp, offset); 481 *bpp = bp; 482 return (0); 483 } 484 485