| File: | isofs/cd9660/cd9660_lookup.c |
| Warning: | line 259, column 18 Although the value stored to 'res' is used in the enclosing expression, the value is never actually read from 'res' |
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| 1 | /* $OpenBSD: cd9660_lookup.c,v 1.30 2022/01/11 03:13:58 jsg Exp $ */ |
| 2 | /* $NetBSD: cd9660_lookup.c,v 1.18 1997/05/08 16:19:59 mycroft Exp $ */ |
| 3 | |
| 4 | /*- |
| 5 | * Copyright (c) 1989, 1993, 1994 |
| 6 | * The Regents of the University of California. All rights reserved. |
| 7 | * |
| 8 | * This code is derived from software contributed to Berkeley |
| 9 | * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension |
| 10 | * Support code is derived from software contributed to Berkeley |
| 11 | * by Atsushi Murai (amurai@spec.co.jp). |
| 12 | * |
| 13 | * Redistribution and use in source and binary forms, with or without |
| 14 | * modification, are permitted provided that the following conditions |
| 15 | * are met: |
| 16 | * 1. Redistributions of source code must retain the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer. |
| 18 | * 2. Redistributions in binary form must reproduce the above copyright |
| 19 | * notice, this list of conditions and the following disclaimer in the |
| 20 | * documentation and/or other materials provided with the distribution. |
| 21 | * 3. Neither the name of the University nor the names of its contributors |
| 22 | * may be used to endorse or promote products derived from this software |
| 23 | * without specific prior written permission. |
| 24 | * |
| 25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 35 | * SUCH DAMAGE. |
| 36 | * |
| 37 | * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 |
| 38 | * |
| 39 | * @(#)cd9660_lookup.c 8.5 (Berkeley) 12/5/94 |
| 40 | */ |
| 41 | |
| 42 | #include <sys/param.h> |
| 43 | #include <sys/namei.h> |
| 44 | #include <sys/buf.h> |
| 45 | #include <sys/vnode.h> |
| 46 | #include <sys/lock.h> |
| 47 | #include <sys/mount.h> |
| 48 | #include <sys/systm.h> |
| 49 | #include <sys/malloc.h> |
| 50 | |
| 51 | #include <isofs/cd9660/iso.h> |
| 52 | #include <isofs/cd9660/cd9660_extern.h> |
| 53 | #include <isofs/cd9660/cd9660_node.h> |
| 54 | #include <isofs/cd9660/iso_rrip.h> |
| 55 | |
| 56 | struct nchstats iso_nchstats; |
| 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 cd9660_lookup: |
| 76 | * |
| 77 | * check accessibility of directory |
| 78 | * look for name in cache, if found, then if at end of path |
| 79 | * and deleting or creating, drop it, else return name |
| 80 | * search for name in directory, to found or notfound |
| 81 | * notfound: |
| 82 | * if creating, return locked directory, leaving info on available slots |
| 83 | * else return error |
| 84 | * found: |
| 85 | * if at end of path and deleting, return information to allow delete |
| 86 | * if at end of path and rewriting (RENAME and LOCKPARENT), lock target |
| 87 | * inode and return info to allow rewrite |
| 88 | * if not at end, add name to cache; if at end and neither creating |
| 89 | * nor deleting, add name to cache |
| 90 | * |
| 91 | * NOTE: (LOOKUP | LOCKPARENT) currently returns the parent inode unlocked. |
| 92 | */ |
| 93 | int |
| 94 | cd9660_lookup(void *v) |
| 95 | { |
| 96 | struct vop_lookup_args *ap = v; |
| 97 | struct vnode *vdp; /* vnode for directory being searched */ |
| 98 | struct iso_node *dp; /* inode for directory being searched */ |
| 99 | struct iso_mnt *imp; /* file system that directory is in */ |
| 100 | struct buf *bp; /* a buffer of directory entries */ |
| 101 | struct iso_directory_record *ep = NULL((void *)0); |
| 102 | /* the current directory entry */ |
| 103 | int entryoffsetinblock; /* offset of ep in bp's buffer */ |
| 104 | int saveoffset = -1; /* offset of last directory entry in dir */ |
| 105 | int numdirpasses; /* strategy for directory search */ |
| 106 | doff_tu_quad_t endsearch; /* offset to end directory search */ |
| 107 | struct vnode *pdp; /* saved dp during symlink work */ |
| 108 | struct vnode *tdp; /* returned by cd9660_vget_internal */ |
| 109 | u_long bmask; /* block offset mask */ |
| 110 | int lockparent; /* 1 => lockparent flag is set */ |
| 111 | int error; |
| 112 | cdino_t ino = 0; |
| 113 | int reclen; |
| 114 | u_short namelen; |
| 115 | char *altname; |
| 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 | struct ucred *cred = cnp->cn_cred; |
| 122 | int flags; |
| 123 | int nameiop = cnp->cn_nameiop; |
| 124 | |
| 125 | cnp->cn_flags &= ~PDIRUNLOCK0x200000; |
| 126 | flags = cnp->cn_flags; |
| 127 | |
| 128 | bp = NULL((void *)0); |
| 129 | *vpp = NULL((void *)0); |
| 130 | vdp = ap->a_dvp; |
| 131 | dp = VTOI(vdp)((struct iso_node *)(vdp)->v_data); |
| 132 | imp = dp->i_mnt; |
| 133 | lockparent = flags & LOCKPARENT0x0008; |
| 134 | |
| 135 | /* |
| 136 | * Check accessibility of directory. |
| 137 | */ |
| 138 | if ((error = VOP_ACCESS(vdp, VEXEC00100, cred, cnp->cn_proc)) != 0) |
| 139 | return (error); |
| 140 | |
| 141 | if ((flags & ISLASTCN0x008000) && (vdp->v_mount->mnt_flag & MNT_RDONLY0x00000001) && |
| 142 | (cnp->cn_nameiop == DELETE2 || cnp->cn_nameiop == RENAME3)) |
| 143 | return (EROFS30); |
| 144 | |
| 145 | /* |
| 146 | * We now have a segment name to search for, and a directory to search. |
| 147 | * |
| 148 | * Before tediously performing a linear scan of the directory, |
| 149 | * check the name cache to see if the directory/name pair |
| 150 | * we are looking for is known already. |
| 151 | */ |
| 152 | if ((error = cache_lookup(vdp, vpp, cnp)) >= 0) |
| 153 | return (error); |
| 154 | |
| 155 | len = cnp->cn_namelen; |
| 156 | name = cnp->cn_nameptr; |
| 157 | /* |
| 158 | * A leading `=' means, we are looking for an associated file |
| 159 | */ |
| 160 | assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR'='); |
| 161 | if (assoc) { |
| 162 | len--; |
| 163 | name++; |
| 164 | } |
| 165 | |
| 166 | /* |
| 167 | * If there is cached information on a previous search of |
| 168 | * this directory, pick up where we last left off. |
| 169 | * We cache only lookups as these are the most common |
| 170 | * and have the greatest payoff. Caching CREATE has little |
| 171 | * benefit as it usually must search the entire directory |
| 172 | * to determine that the entry does not exist. Caching the |
| 173 | * location of the last DELETE or RENAME has not reduced |
| 174 | * profiling time and hence has been removed in the interest |
| 175 | * of simplicity. |
| 176 | */ |
| 177 | bmask = imp->im_bmask; |
| 178 | if (nameiop != LOOKUP0 || dp->i_diroff == 0 || |
| 179 | dp->i_diroff > dp->i_size) { |
| 180 | entryoffsetinblock = 0; |
| 181 | dp->i_offset = 0; |
| 182 | numdirpasses = 1; |
| 183 | } else { |
| 184 | dp->i_offset = dp->i_diroff; |
| 185 | if ((entryoffsetinblock = dp->i_offset & bmask) && |
| 186 | (error = cd9660_bufatoff(dp, (off_t)dp->i_offset, NULL((void *)0), |
| 187 | &bp))) |
| 188 | return (error); |
| 189 | numdirpasses = 2; |
| 190 | iso_nchstats.ncs_2passes++; |
| 191 | } |
| 192 | endsearch = dp->i_size; |
| 193 | |
| 194 | searchloop: |
| 195 | while (dp->i_offset < endsearch) { |
| 196 | /* |
| 197 | * If offset is on a block boundary, |
| 198 | * read the next directory block. |
| 199 | * Release previous if it exists. |
| 200 | */ |
| 201 | if ((dp->i_offset & bmask) == 0) { |
| 202 | if (bp != NULL((void *)0)) |
| 203 | brelse(bp); |
| 204 | error = cd9660_bufatoff(dp, (off_t)dp->i_offset, |
| 205 | NULL((void *)0), &bp); |
| 206 | if (error) |
| 207 | return (error); |
| 208 | entryoffsetinblock = 0; |
| 209 | } |
| 210 | /* |
| 211 | * Get pointer to next entry. |
| 212 | */ |
| 213 | ep = (struct iso_directory_record *) |
| 214 | ((char *)bp->b_data + entryoffsetinblock); |
| 215 | |
| 216 | reclen = isonum_711(ep->length); |
| 217 | if (reclen == 0) { |
| 218 | /* skip to next block, if any */ |
| 219 | dp->i_offset = |
| 220 | (dp->i_offset & ~bmask) + imp->logical_block_size; |
| 221 | continue; |
| 222 | } |
| 223 | |
| 224 | if (reclen < ISO_DIRECTORY_RECORD_SIZE33) |
| 225 | /* illegal entry, stop */ |
| 226 | break; |
| 227 | |
| 228 | if (entryoffsetinblock + reclen > imp->logical_block_size) |
| 229 | /* entries are not allowed to cross boundaries */ |
| 230 | break; |
| 231 | |
| 232 | namelen = isonum_711(ep->name_len); |
| 233 | |
| 234 | if (reclen < ISO_DIRECTORY_RECORD_SIZE33 + namelen) |
| 235 | /* illegal entry, stop */ |
| 236 | break; |
| 237 | |
| 238 | /* |
| 239 | * Check for a name match. |
| 240 | */ |
| 241 | switch (imp->iso_ftype) { |
| 242 | default: |
| 243 | if ((!(isonum_711(ep->flags)&4)) == !assoc) { |
| 244 | if ((len == 1 |
| 245 | && *name == '.') |
| 246 | || (flags & ISDOTDOT0x002000)) { |
| 247 | if (namelen == 1 |
| 248 | && ep->name[0] == ((flags & ISDOTDOT0x002000) ? 1 : 0)) { |
| 249 | /* |
| 250 | * Save directory entry's inode number and |
| 251 | * release directory buffer. |
| 252 | */ |
| 253 | dp->i_ino = isodirino(ep, imp); |
| 254 | goto found; |
| 255 | } |
| 256 | if (namelen != 1 |
| 257 | || ep->name[0] != 0) |
| 258 | goto notfound; |
| 259 | } else if (!(res = isofncmp(name, len, |
Although the value stored to 'res' is used in the enclosing expression, the value is never actually read from 'res' | |
| 260 | ep->name, namelen, imp->joliet_level))) { |
| 261 | if (isonum_711(ep->flags)&2) |
| 262 | ino = isodirino(ep, imp); |
| 263 | else |
| 264 | ino = dbtob(bp->b_blkno)((bp->b_blkno) << 9) |
| 265 | + entryoffsetinblock; |
| 266 | saveoffset = dp->i_offset; |
| 267 | } else if (ino) |
| 268 | goto foundino; |
| 269 | #ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ |
| 270 | else if (res < 0) |
| 271 | goto notfound; |
| 272 | else if (res > 0 && numdirpasses == 2) |
| 273 | numdirpasses++; |
| 274 | #endif |
| 275 | } |
| 276 | break; |
| 277 | case ISO_FTYPE_RRIP: |
| 278 | if (isonum_711(ep->flags)&2) |
| 279 | ino = isodirino(ep, imp); |
| 280 | else |
| 281 | ino = dbtob(bp->b_blkno)((bp->b_blkno) << 9) + entryoffsetinblock; |
| 282 | dp->i_ino = ino; |
| 283 | altname = malloc(NAME_MAX255, M_TEMP127, M_WAITOK0x0001); |
| 284 | cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); |
| 285 | if (namelen == cnp->cn_namelen |
| 286 | && !bcmp(name,altname,namelen)) { |
| 287 | free(altname, M_TEMP127, 0); |
| 288 | goto found; |
| 289 | } |
| 290 | free(altname, M_TEMP127, 0); |
| 291 | ino = 0; |
| 292 | break; |
| 293 | } |
| 294 | dp->i_offset += reclen; |
| 295 | entryoffsetinblock += reclen; |
| 296 | } |
| 297 | if (ino) { |
| 298 | foundino: |
| 299 | dp->i_ino = ino; |
| 300 | if (saveoffset != dp->i_offset) { |
| 301 | if (lblkno(imp, dp->i_offset)((dp->i_offset) >> (imp)->im_bshift) != |
| 302 | lblkno(imp, saveoffset)((saveoffset) >> (imp)->im_bshift)) { |
| 303 | if (bp != NULL((void *)0)) |
| 304 | brelse(bp); |
| 305 | if ((error = cd9660_bufatoff(dp, |
| 306 | (off_t)saveoffset, NULL((void *)0), &bp)) != 0) |
| 307 | return (error); |
| 308 | } |
| 309 | entryoffsetinblock = saveoffset & bmask; |
| 310 | ep = (struct iso_directory_record *) |
| 311 | ((char *)bp->b_data + entryoffsetinblock); |
| 312 | dp->i_offset = saveoffset; |
| 313 | } |
| 314 | goto found; |
| 315 | } |
| 316 | notfound: |
| 317 | /* |
| 318 | * If we started in the middle of the directory and failed |
| 319 | * to find our target, we must check the beginning as well. |
| 320 | */ |
| 321 | if (numdirpasses == 2) { |
| 322 | numdirpasses--; |
| 323 | dp->i_offset = 0; |
| 324 | endsearch = dp->i_diroff; |
| 325 | goto searchloop; |
| 326 | } |
| 327 | if (bp != NULL((void *)0)) |
| 328 | brelse(bp); |
| 329 | |
| 330 | /* |
| 331 | * Insert name into cache (as non-existent) if appropriate. |
| 332 | */ |
| 333 | if (cnp->cn_flags & MAKEENTRY0x004000) |
| 334 | cache_enter(vdp, *vpp, cnp); |
| 335 | if (nameiop == CREATE1 || nameiop == RENAME3) |
| 336 | return (EJUSTRETURN-2); |
| 337 | return (ENOENT2); |
| 338 | |
| 339 | found: |
| 340 | if (numdirpasses == 2) |
| 341 | iso_nchstats.ncs_pass2++; |
| 342 | |
| 343 | /* |
| 344 | * Found component in pathname. |
| 345 | * If the final component of path name, save information |
| 346 | * in the cache as to where the entry was found. |
| 347 | */ |
| 348 | if ((flags & ISLASTCN0x008000) && nameiop == LOOKUP0) |
| 349 | dp->i_diroff = dp->i_offset; |
| 350 | |
| 351 | /* |
| 352 | * Step through the translation in the name. We do not `iput' the |
| 353 | * directory because we may need it again if a symbolic link |
| 354 | * is relative to the current directory. Instead we save it |
| 355 | * unlocked as "pdp". We must get the target inode before unlocking |
| 356 | * the directory to insure that the inode will not be removed |
| 357 | * before we get it. We prevent deadlock by always fetching |
| 358 | * inodes from the root, moving down the directory tree. Thus |
| 359 | * when following backward pointers ".." we must unlock the |
| 360 | * parent directory before getting the requested directory. |
| 361 | * There is a potential race condition here if both the current |
| 362 | * and parent directories are removed before the `iget' for the |
| 363 | * inode associated with ".." returns. We hope that this occurs |
| 364 | * infrequently since we cannot avoid this race condition without |
| 365 | * implementing a sophisticated deadlock detection algorithm. |
| 366 | * Note also that this simple deadlock detection scheme will not |
| 367 | * work if the file system has any hard links other than ".." |
| 368 | * that point backwards in the directory structure. |
| 369 | */ |
| 370 | pdp = vdp; |
| 371 | /* |
| 372 | * If ino is different from dp->i_ino, |
| 373 | * it's a relocated directory. |
| 374 | */ |
| 375 | if (flags & ISDOTDOT0x002000) { |
| 376 | brelse(bp); |
| 377 | VOP_UNLOCK(pdp); /* race to get the inode */ |
| 378 | cnp->cn_flags |= PDIRUNLOCK0x200000; |
| 379 | error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, |
| 380 | dp->i_ino != ino, NULL((void *)0)); |
| 381 | if (error) { |
| 382 | if (vn_lock(pdp, LK_EXCLUSIVE0x0001UL | LK_RETRY0x2000UL) == 0) |
| 383 | cnp->cn_flags &= ~PDIRUNLOCK0x200000; |
| 384 | return (error); |
| 385 | } |
| 386 | if (lockparent && (flags & ISLASTCN0x008000)) { |
| 387 | if ((error = vn_lock(pdp, LK_EXCLUSIVE0x0001UL))) { |
| 388 | vput(tdp); |
| 389 | return (error); |
| 390 | } |
| 391 | cnp->cn_flags &= ~PDIRUNLOCK0x200000; |
| 392 | } |
| 393 | *vpp = tdp; |
| 394 | } else if (dp->i_number == dp->i_ino) { |
| 395 | brelse(bp); |
| 396 | vref(vdp); /* we want ourself, ie "." */ |
| 397 | *vpp = vdp; |
| 398 | } else { |
| 399 | error = cd9660_vget_internal(vdp->v_mount, dp->i_ino, &tdp, |
| 400 | dp->i_ino != ino, ep); |
| 401 | brelse(bp); |
| 402 | if (error) |
| 403 | return (error); |
| 404 | if (!lockparent || !(flags & ISLASTCN0x008000)) { |
| 405 | VOP_UNLOCK(pdp); |
| 406 | cnp->cn_flags |= PDIRUNLOCK0x200000; |
| 407 | } |
| 408 | *vpp = tdp; |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * Insert name into cache if appropriate. |
| 413 | */ |
| 414 | if (cnp->cn_flags & MAKEENTRY0x004000) |
| 415 | cache_enter(vdp, *vpp, cnp); |
| 416 | return (0); |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Return buffer with the contents of block "offset" from the beginning of |
| 421 | * directory "ip". If "res" is non-zero, fill it in with a pointer to the |
| 422 | * remaining space in the directory. |
| 423 | */ |
| 424 | int |
| 425 | cd9660_bufatoff(struct iso_node *ip, off_t offset, char **res, |
| 426 | struct buf **bpp) |
| 427 | { |
| 428 | struct iso_mnt *imp; |
| 429 | struct buf *bp; |
| 430 | daddr_t lbn; |
| 431 | int bsize, error; |
| 432 | struct vnode *vp = ITOV(ip)((ip)->i_vnode); |
| 433 | |
| 434 | imp = ip->i_mnt; |
| 435 | lbn = lblkno(imp, offset)((offset) >> (imp)->im_bshift); |
| 436 | bsize = blksize(imp, ip, lbn)((imp)->logical_block_size); |
| 437 | |
| 438 | if ((error = bread(vp, lbn, bsize, &bp)) != 0) { |
| 439 | brelse(bp); |
| 440 | *bpp = NULL((void *)0); |
| 441 | return (error); |
| 442 | } |
| 443 | if (res) |
| 444 | *res = (char *)bp->b_data + blkoff(imp, offset)((offset) & (imp)->im_bmask); |
| 445 | *bpp = bp; |
| 446 | return (0); |
| 447 | } |