1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley 8 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension 9 * Support code is derived from software contributed to Berkeley 10 * by Atsushi Murai (amurai@spec.co.jp). 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/namei.h> 40 #include <sys/bio.h> 41 #include <sys/buf.h> 42 #include <sys/vnode.h> 43 #include <sys/mount.h> 44 45 #include <fs/cd9660/iso.h> 46 #include <fs/cd9660/cd9660_node.h> 47 #include <fs/cd9660/iso_rrip.h> 48 49 struct cd9660_ino_alloc_arg { 50 cd_ino_t ino; 51 cd_ino_t i_ino; 52 struct iso_directory_record *ep; 53 }; 54 55 static int 56 cd9660_ino_alloc(struct mount *mp, void *arg, int lkflags, 57 struct vnode **vpp) 58 { 59 struct cd9660_ino_alloc_arg *dd_arg; 60 61 dd_arg = arg; 62 return (cd9660_vget_internal(mp, dd_arg->i_ino, lkflags, vpp, 63 dd_arg->i_ino != dd_arg->ino, dd_arg->ep)); 64 } 65 66 /* 67 * Convert a component of a pathname into a pointer to a locked inode. 68 * This is a very central and rather complicated routine. 69 * If the filesystem is not maintained in a strict tree hierarchy, 70 * this can result in a deadlock situation (see comments in code below). 71 * 72 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 73 * whether the name is to be looked up, created, renamed, or deleted. 74 * When CREATE, RENAME, or DELETE is specified, information usable in 75 * creating, renaming, or deleting a directory entry may be calculated. 76 * If flag has LOCKPARENT or'ed into it and the target of the pathname 77 * exists, lookup returns both the target and its parent directory locked. 78 * When creating or renaming and LOCKPARENT is specified, the target may 79 * not be ".". When deleting and LOCKPARENT is specified, the target may 80 * be "."., but the caller must check to ensure it does an vrele and iput 81 * instead of two iputs. 82 * 83 * Overall outline of ufs_lookup: 84 * 85 * search for name in directory, to found or notfound 86 * notfound: 87 * if creating, return locked directory, leaving info on available slots 88 * else return error 89 * found: 90 * if at end of path and deleting, return information to allow delete 91 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 92 * inode and return info to allow rewrite 93 * if not at end, add name to cache; if at end and neither creating 94 * nor deleting, add name to cache 95 * 96 * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. 97 */ 98 int 99 cd9660_lookup(struct vop_cachedlookup_args *ap) 100 { 101 struct vnode *vdp; /* vnode for directory being searched */ 102 struct iso_node *dp; /* inode for directory being searched */ 103 struct iso_mnt *imp; /* filesystem that directory is in */ 104 struct buf *bp; /* a buffer of directory entries */ 105 struct iso_directory_record *ep;/* the current directory entry */ 106 struct iso_directory_record *ep2;/* copy of current directory entry */ 107 int entryoffsetinblock; /* offset of ep in bp's buffer */ 108 int saveoffset = 0; /* offset of last directory entry in dir */ 109 doff_t i_diroff; /* cached i_diroff value. */ 110 doff_t i_offset; /* cached i_offset value. */ 111 int numdirpasses; /* strategy for directory search */ 112 doff_t endsearch; /* offset to end directory search */ 113 struct vnode *pdp; /* saved dp during symlink work */ 114 struct vnode *tdp; /* returned by cd9660_vget_internal */ 115 struct cd9660_ino_alloc_arg dd_arg; 116 u_long bmask; /* block offset mask */ 117 int error; 118 cd_ino_t ino, i_ino; 119 int ltype, reclen; 120 u_short namelen; 121 int isoflags; 122 char altname[NAME_MAX]; 123 int res; 124 int assoc, len; 125 char *name; 126 struct vnode **vpp = ap->a_vpp; 127 struct componentname *cnp = ap->a_cnp; 128 int flags = cnp->cn_flags; 129 int nameiop = cnp->cn_nameiop; 130 131 ep2 = ep = NULL; 132 bp = NULL; 133 *vpp = NULL; 134 vdp = ap->a_dvp; 135 dp = VTOI(vdp); 136 imp = dp->i_mnt; 137 138 /* 139 * We now have a segment name to search for, and a directory to search. 140 */ 141 ino = reclen = 0; 142 i_diroff = dp->i_diroff; 143 len = cnp->cn_namelen; 144 name = cnp->cn_nameptr; 145 146 /* 147 * A leading `=' means, we are looking for an associated file 148 */ 149 if ((assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR))) 150 { 151 len--; 152 name++; 153 } 154 155 /* 156 * If there is cached information on a previous search of 157 * this directory, pick up where we last left off. 158 * We cache only lookups as these are the most common 159 * and have the greatest payoff. Caching CREATE has little 160 * benefit as it usually must search the entire directory 161 * to determine that the entry does not exist. Caching the 162 * location of the last DELETE or RENAME has not reduced 163 * profiling time and hence has been removed in the interest 164 * of simplicity. 165 */ 166 bmask = imp->im_bmask; 167 if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) { 168 entryoffsetinblock = 0; 169 i_offset = 0; 170 numdirpasses = 1; 171 } else { 172 i_offset = i_diroff; 173 if ((entryoffsetinblock = i_offset & bmask) && 174 (error = cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp))) 175 return (error); 176 numdirpasses = 2; 177 nchstats.ncs_2passes++; 178 } 179 endsearch = dp->i_size; 180 181 searchloop: 182 while (i_offset < endsearch) { 183 /* 184 * If offset is on a block boundary, 185 * read the next directory block. 186 * Release previous if it exists. 187 */ 188 if ((i_offset & bmask) == 0) { 189 if (bp != NULL) 190 brelse(bp); 191 if ((error = 192 cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)) != 0) 193 return (error); 194 entryoffsetinblock = 0; 195 } 196 /* 197 * Get pointer to next entry. 198 */ 199 ep = (struct iso_directory_record *) 200 ((char *)bp->b_data + entryoffsetinblock); 201 202 reclen = isonum_711(ep->length); 203 if (reclen == 0) { 204 /* skip to next block, if any */ 205 i_offset = 206 (i_offset & ~bmask) + imp->logical_block_size; 207 continue; 208 } 209 210 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 211 /* illegal entry, stop */ 212 break; 213 214 if (entryoffsetinblock + reclen > imp->logical_block_size) 215 /* entries are not allowed to cross boundaries */ 216 break; 217 218 namelen = isonum_711(ep->name_len); 219 isoflags = isonum_711(imp->iso_ftype == ISO_FTYPE_HIGH_SIERRA? 220 &ep->date[6]: ep->flags); 221 222 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 223 /* illegal entry, stop */ 224 break; 225 226 /* 227 * Check for a name match. 228 */ 229 switch (imp->iso_ftype) { 230 default: 231 if (!(isoflags & 4) == !assoc) { 232 if ((len == 1 233 && *name == '.') 234 || (flags & ISDOTDOT)) { 235 if (namelen == 1 236 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 237 /* 238 * Save directory entry's inode number and 239 * release directory buffer. 240 */ 241 i_ino = isodirino(ep, imp); 242 goto found; 243 } 244 if (namelen != 1 245 || ep->name[0] != 0) 246 goto notfound; 247 } else if (!(res = isofncmp(name, len, 248 ep->name, namelen, 249 imp->joliet_level, 250 imp->im_flags, 251 imp->im_d2l, 252 imp->im_l2d))) { 253 if (isoflags & 2) 254 ino = isodirino(ep, imp); 255 else 256 ino = dbtob(bp->b_blkno) 257 + entryoffsetinblock; 258 saveoffset = i_offset; 259 } else if (ino) 260 goto foundino; 261 #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 262 else if (res < 0) 263 goto notfound; 264 else if (res > 0 && numdirpasses == 2) 265 numdirpasses++; 266 #endif 267 } 268 break; 269 case ISO_FTYPE_RRIP: 270 if (isonum_711(ep->flags)&2) 271 ino = isodirino(ep, imp); 272 else 273 ino = dbtob(bp->b_blkno) + entryoffsetinblock; 274 i_ino = ino; 275 cd9660_rrip_getname(ep, altname, &namelen, &i_ino, imp); 276 if (namelen == cnp->cn_namelen 277 && !bcmp(name,altname,namelen)) 278 goto found; 279 ino = 0; 280 break; 281 } 282 i_offset += reclen; 283 entryoffsetinblock += reclen; 284 } 285 if (ino) { 286 foundino: 287 i_ino = ino; 288 if (saveoffset != i_offset) { 289 if (lblkno(imp, i_offset) != 290 lblkno(imp, saveoffset)) { 291 if (bp != NULL) 292 brelse(bp); 293 if ((error = cd9660_blkatoff(vdp, 294 (off_t)saveoffset, NULL, &bp)) != 0) 295 return (error); 296 } 297 entryoffsetinblock = saveoffset & bmask; 298 ep = (struct iso_directory_record *) 299 ((char *)bp->b_data + entryoffsetinblock); 300 reclen = isonum_711(ep->length); 301 i_offset = saveoffset; 302 } 303 goto found; 304 } 305 notfound: 306 /* 307 * If we started in the middle of the directory and failed 308 * to find our target, we must check the beginning as well. 309 */ 310 if (numdirpasses == 2) { 311 numdirpasses--; 312 i_offset = 0; 313 endsearch = i_diroff; 314 goto searchloop; 315 } 316 if (bp != NULL) 317 brelse(bp); 318 319 /* 320 * Insert name into cache (as non-existent) if appropriate. 321 */ 322 if (cnp->cn_flags & MAKEENTRY) 323 cache_enter(vdp, *vpp, cnp); 324 if (nameiop == CREATE || nameiop == RENAME) 325 return (EROFS); 326 return (ENOENT); 327 328 found: 329 if (numdirpasses == 2) 330 nchstats.ncs_pass2++; 331 332 /* 333 * Found component in pathname. 334 * If the final component of path name, save information 335 * in the cache as to where the entry was found. 336 */ 337 if ((flags & ISLASTCN) && nameiop == LOOKUP) 338 dp->i_diroff = i_offset; 339 340 /* 341 * Step through the translation in the name. We do not `vput' the 342 * directory because we may need it again if a symbolic link 343 * is relative to the current directory. Instead we save it 344 * unlocked as "pdp". We must get the target inode before unlocking 345 * the directory to insure that the inode will not be removed 346 * before we get it. We prevent deadlock by always fetching 347 * inodes from the root, moving down the directory tree. Thus 348 * when following backward pointers ".." we must unlock the 349 * parent directory before getting the requested directory. 350 * There is a potential race condition here if both the current 351 * and parent directories are removed before the `vget' for the 352 * inode associated with ".." returns. We hope that this occurs 353 * infrequently since we cannot avoid this race condition without 354 * implementing a sophisticated deadlock detection algorithm. 355 * Note also that this simple deadlock detection scheme will not 356 * work if the filesystem has any hard links other than ".." 357 * that point backwards in the directory structure. 358 */ 359 pdp = vdp; 360 361 /* 362 * Make a copy of the directory entry for non "." lookups so 363 * we can drop the buffer before calling vget() to avoid a 364 * lock order reversal between the vnode lock and the buffer 365 * lock. 366 */ 367 if (dp->i_number != i_ino) { 368 ep2 = malloc(reclen, M_TEMP, M_WAITOK); 369 memcpy(ep2, ep, reclen); 370 ep = ep2; 371 } 372 brelse(bp); 373 374 /* 375 * If ino is different from i_ino, 376 * it's a relocated directory. 377 */ 378 if (flags & ISDOTDOT) { 379 dd_arg.ino = ino; 380 dd_arg.i_ino = i_ino; 381 dd_arg.ep = ep; 382 error = vn_vget_ino_gen(pdp, cd9660_ino_alloc, &dd_arg, 383 cnp->cn_lkflags, &tdp); 384 free(ep2, M_TEMP); 385 if (error != 0) 386 return (error); 387 *vpp = tdp; 388 } else if (dp->i_number == i_ino) { 389 VREF(vdp); /* we want ourself, ie "." */ 390 /* 391 * When we lookup "." we still can be asked to lock it 392 * differently. 393 */ 394 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 395 if (ltype != VOP_ISLOCKED(vdp)) { 396 if (ltype == LK_EXCLUSIVE) 397 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 398 else /* if (ltype == LK_SHARED) */ 399 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 400 } 401 *vpp = vdp; 402 } else { 403 error = cd9660_vget_internal(vdp->v_mount, i_ino, 404 cnp->cn_lkflags, &tdp, 405 i_ino != ino, ep); 406 free(ep2, M_TEMP); 407 if (error) 408 return (error); 409 *vpp = tdp; 410 } 411 412 /* 413 * Insert name into cache if appropriate. 414 */ 415 if (cnp->cn_flags & MAKEENTRY) 416 cache_enter(vdp, *vpp, cnp); 417 return (0); 418 } 419 420 /* 421 * Return buffer with the contents of block "offset" from the beginning of 422 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 423 * remaining space in the directory. 424 */ 425 int 426 cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 427 { 428 struct iso_node *ip; 429 struct iso_mnt *imp; 430 struct buf *bp; 431 daddr_t lbn; 432 int bsize, bshift, error; 433 434 ip = VTOI(vp); 435 imp = ip->i_mnt; 436 lbn = lblkno(imp, offset); 437 bsize = blksize(imp, ip, lbn); 438 bshift = imp->im_bshift; 439 440 if ((error = bread(vp, lbn, bsize, NOCRED, &bp)) != 0) { 441 brelse(bp); 442 *bpp = NULL; 443 return (error); 444 } 445 446 /* 447 * We must BMAP the buffer because the directory code may use b_blkno 448 * to calculate the inode for certain types of directory entries. 449 * We could get away with not doing it before we VMIO-backed the 450 * directories because the buffers would get freed atomically with 451 * the invalidation of their data. But with VMIO-backed buffers 452 * the buffers may be freed and then later reconstituted - and the 453 * reconstituted buffer will have no knowledge of b_blkno. 454 */ 455 if (bp->b_blkno == bp->b_lblkno) { 456 bp->b_blkno = (ip->iso_start + bp->b_lblkno) << (bshift - DEV_BSHIFT); 457 } 458 459 if (res) 460 *res = (char *)bp->b_data + blkoff(imp, offset); 461 *bpp = bp; 462 return (0); 463 } 464