1/* $NetBSD: cd9660_lookup.c,v 1.32 2022/08/06 18:26:41 andvar Exp $ */ 2 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 * from: @(#)ufs_lookup.c 7.33 (Berkeley) 5/19/91 37 * 38 * @(#)cd9660_lookup.c 8.5 (Berkeley) 5/27/95 39 */ 40 41#include <sys/cdefs.h> 42__KERNEL_RCSID(0, "$NetBSD: cd9660_lookup.c,v 1.32 2022/08/06 18:26:41 andvar Exp $"); 43 44#include <sys/param.h> 45#include <sys/namei.h> 46#include <sys/buf.h> 47#include <sys/file.h> 48#include <sys/vnode.h> 49#include <sys/mount.h> 50#include <sys/systm.h> 51#include <sys/kauth.h> 52 53#include <fs/cd9660/iso.h> 54#include <fs/cd9660/cd9660_extern.h> 55#include <fs/cd9660/cd9660_node.h> 56#include <fs/cd9660/iso_rrip.h> 57#include <fs/cd9660/cd9660_rrip.h> 58#include <fs/cd9660/cd9660_mount.h> 59 60/* 61 * Convert a component of a pathname into a pointer to a locked inode. 62 * This is a very central and rather complicated routine. 63 * If the file system is not maintained in a strict tree hierarchy, 64 * this can result in a deadlock situation (see comments in code below). 65 * 66 * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on 67 * whether the name is to be looked up, created, renamed, or deleted. 68 * When CREATE, RENAME, or DELETE is specified, information usable in 69 * creating, renaming, or deleting a directory entry may be calculated. 70 * If the target of the pathname exists, lookup returns both the target 71 * and its parent directory locked. 72 * When creating or renaming, the target may * not be ".". 73 * When deleting , the target may be "."., but the caller must check 74 * to ensure it does an vrele and vput instead of two vputs. 75 * 76 * Overall outline of ufs_lookup: 77 * 78 * check accessibility of directory 79 * look for name in cache, if found, then if at end of path 80 * and deleting or creating, drop it, else return name 81 * search for name in directory, to found or notfound 82 * notfound: 83 * if creating, return locked directory, leaving info on available slots 84 * else return error 85 * found: 86 * if at end of path and deleting, return information to allow delete 87 * if at end of path and rewriting (RENAME), lock target 88 * inode and return info to allow rewrite 89 * if not at end, add name to cache; if at end and neither creating 90 * nor deleting, add name to cache 91 */ 92int 93cd9660_lookup(void *v) 94{ 95 struct vop_lookup_v2_args /* { 96 struct vnode *a_dvp; 97 struct vnode **a_vpp; 98 struct componentname *a_cnp; 99 } */ *ap = v; 100 struct vnode *vdp; /* vnode for directory being searched */ 101 struct iso_node *dp; /* inode for directory being searched */ 102 struct iso_mnt *imp; /* file system that directory is in */ 103 struct buf *bp; /* a buffer of directory entries */ 104 struct iso_directory_record *ep = NULL; 105 /* the current directory entry */ 106 int entryoffsetinblock; /* offset of ep in bp's buffer */ 107 int saveoffset = -1; /* offset of last directory entry in dir */ 108 int numdirpasses; /* strategy for directory search */ 109 doff_t endsearch; /* offset to end directory search */ 110 struct vnode *tdp; /* returned by vcache_get */ 111 u_long bmask; /* block offset mask */ 112 int error; 113 ino_t ino = 0; 114 int reclen; 115 u_short namelen; 116 char altname[ISO_MAXNAMLEN]; 117 int res; 118 int assoc, len; 119 const char *name; 120 struct vnode **vpp = ap->a_vpp; 121 struct componentname *cnp = ap->a_cnp; 122 kauth_cred_t cred = cnp->cn_cred; 123 int flags; 124 int nameiop = cnp->cn_nameiop; 125 126 flags = cnp->cn_flags; 127 128 bp = NULL; 129 *vpp = NULL; 130 vdp = ap->a_dvp; 131 dp = VTOI(vdp); 132 imp = dp->i_mnt; 133 134 /* 135 * Check accessibility of directory. 136 */ 137 if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) 138 return (error); 139 140 if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && 141 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 142 return (EROFS); 143 144 /* 145 * We now have a segment name to search for, and a directory to search. 146 * 147 * Before tediously performing a linear scan of the directory, 148 * check the name cache to see if the directory/name pair 149 * we are looking for is known already. 150 */ 151 if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, 152 cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) { 153 return *vpp == NULLVP ? ENOENT : 0; 154 } 155 /* May need to restart the lookup with an exclusive lock. */ 156 if (VOP_ISLOCKED(vdp) != LK_EXCLUSIVE) 157 return ENOLCK; 158 159 len = cnp->cn_namelen; 160 name = cnp->cn_nameptr; 161 /* 162 * A leading `=' means, we are looking for an associated file 163 */ 164 assoc = (imp->iso_ftype != ISO_FTYPE_RRIP && *name == ASSOCCHAR); 165 if (assoc) { 166 len--; 167 name++; 168 } 169 170 /* 171 * If there is cached information on a previous search of 172 * this directory, pick up where we last left off. 173 * We cache only lookups as these are the most common 174 * and have the greatest payoff. Caching CREATE has little 175 * benefit as it usually must search the entire directory 176 * to determine that the entry does not exist. Caching the 177 * location of the last DELETE or RENAME has not reduced 178 * profiling time and hence has been removed in the interest 179 * of simplicity. 180 */ 181 bmask = imp->im_bmask; 182 if (nameiop != LOOKUP || dp->i_diroff == 0 || 183 dp->i_diroff > dp->i_size) { 184 entryoffsetinblock = 0; 185 dp->i_offset = 0; 186 numdirpasses = 1; 187 } else { 188 dp->i_offset = dp->i_diroff; 189 if ((entryoffsetinblock = dp->i_offset & bmask) && 190 (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL, 191 &bp))) 192 return (error); 193 numdirpasses = 2; 194 namecache_count_2passes(); 195 } 196 endsearch = dp->i_size; 197 198searchloop: 199 while (dp->i_offset < endsearch) { 200 /* 201 * If offset is on a block boundary, 202 * read the next directory block. 203 * Release previous if it exists. 204 */ 205 if ((dp->i_offset & bmask) == 0) { 206 if (bp != NULL) 207 brelse(bp, 0); 208 error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, 209 NULL, &bp); 210 if (error) 211 return (error); 212 entryoffsetinblock = 0; 213 } 214 /* 215 * Get pointer to next entry. 216 */ 217 KASSERT(bp != NULL); 218 ep = (struct iso_directory_record *) 219 ((char *)bp->b_data + entryoffsetinblock); 220 221 reclen = isonum_711(ep->length); 222 if (reclen == 0) { 223 /* skip to next block, if any */ 224 dp->i_offset = 225 (dp->i_offset & ~bmask) + imp->logical_block_size; 226 continue; 227 } 228 229 if (reclen < ISO_DIRECTORY_RECORD_SIZE) 230 /* illegal entry, stop */ 231 break; 232 233 if (entryoffsetinblock + reclen > imp->logical_block_size) 234 /* entries are not allowed to cross boundaries */ 235 break; 236 237 namelen = isonum_711(ep->name_len); 238 239 if (reclen < ISO_DIRECTORY_RECORD_SIZE + namelen) 240 /* illegal entry, stop */ 241 break; 242 243 /* 244 * Check for a name match. 245 */ 246 switch (imp->iso_ftype) { 247 default: 248 if ((!(isonum_711(ep->flags)&4)) == !assoc) { 249 if ((len == 1 250 && *name == '.') 251 || (flags & ISDOTDOT)) { 252 if (namelen == 1 253 && ep->name[0] == ((flags & ISDOTDOT) ? 1 : 0)) { 254 /* 255 * Save directory entry's inode number and 256 * release directory buffer. 257 */ 258 dp->i_ino = isodirino(ep, imp); 259 goto found; 260 } 261 if (namelen != 1 262 || ep->name[0] != 0) 263 goto notfound; 264 } else if (!(res = isofncmp(name,len, 265 ep->name,namelen, 266 imp->im_joliet_level))) { 267 if (isonum_711(ep->flags)&2) 268 ino = isodirino(ep, imp); 269 else 270 ino = dbtob(bp->b_blkno) 271 + entryoffsetinblock; 272 saveoffset = dp->i_offset; 273 } else if (ino) 274 goto foundino; 275#ifdef NOSORTBUG /* On some CDs directory entries are not sorted correctly */ 276 else if (res < 0) 277 goto notfound; 278 else if (res > 0 && numdirpasses == 2) 279 numdirpasses++; 280#endif 281 } 282 break; 283 case ISO_FTYPE_RRIP: 284 if (isonum_711(ep->flags)&2) 285 ino = isodirino(ep, imp); 286 else 287 ino = dbtob(bp->b_blkno) + entryoffsetinblock; 288 dp->i_ino = ino; 289 cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp); 290 if (namelen == cnp->cn_namelen) { 291 if (imp->im_flags & ISOFSMNT_RRCASEINS) { 292 if (strncasecmp(name, altname, namelen) == 0) 293 goto found; 294 } else { 295 if (memcmp(name, altname, namelen) == 0) 296 goto found; 297 } 298 } 299 ino = 0; 300 break; 301 } 302 dp->i_offset += reclen; 303 entryoffsetinblock += reclen; 304 } 305 if (ino) { 306foundino: 307 dp->i_ino = ino; 308 if (saveoffset != dp->i_offset) { 309 if (cd9660_lblkno(imp, dp->i_offset) != 310 cd9660_lblkno(imp, saveoffset)) { 311 if (bp != NULL) 312 brelse(bp, 0); 313 if ((error = cd9660_blkatoff(vdp, 314 (off_t)saveoffset, NULL, &bp)) != 0) 315 return (error); 316 } 317 entryoffsetinblock = saveoffset & bmask; 318 ep = (struct iso_directory_record *) 319 ((char *)bp->b_data + entryoffsetinblock); 320 dp->i_offset = saveoffset; 321 } 322 goto found; 323 } 324notfound: 325 /* 326 * If we started in the middle of the directory and failed 327 * to find our target, we must check the beginning as well. 328 */ 329 if (numdirpasses == 2) { 330 numdirpasses--; 331 dp->i_offset = 0; 332 endsearch = dp->i_diroff; 333 goto searchloop; 334 } 335 if (bp != NULL) 336 brelse(bp, 0); 337 338 /* 339 * Insert name into cache (as non-existent) if appropriate. 340 */ 341 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); 342 return (nameiop == CREATE || nameiop == RENAME) ? EROFS : ENOENT; 343 344found: 345 if (numdirpasses == 2) 346 namecache_count_pass2(); 347 brelse(bp, 0); 348 349 /* 350 * Found component in pathname. 351 * If the final component of path name, save information 352 * in the cache as to where the entry was found. 353 */ 354 if ((flags & ISLASTCN) && nameiop == LOOKUP) 355 dp->i_diroff = dp->i_offset; 356 357 if (dp->i_number == dp->i_ino) { 358 vref(vdp); /* we want ourself, ie "." */ 359 *vpp = vdp; 360 } else { 361 error = vcache_get(vdp->v_mount, 362 &dp->i_ino, sizeof(dp->i_ino), &tdp); 363 if (error) 364 return (error); 365 *vpp = tdp; 366 } 367 368 /* 369 * Insert name into cache if appropriate. 370 */ 371 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); 372 373 return 0; 374} 375 376/* 377 * Return buffer with the contents of block "offset" from the beginning of 378 * directory "ip". If "res" is non-zero, fill it in with a pointer to the 379 * remaining space in the directory. 380 */ 381int 382cd9660_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp) 383{ 384 struct iso_node *ip; 385 struct iso_mnt *imp; 386 struct vnode *devvp; 387 struct buf *bp; 388 daddr_t lbn; 389 int bsize, error; 390 391 ip = VTOI(vp); 392 imp = ip->i_mnt; 393 lbn = cd9660_lblkno(imp, offset); 394 bsize = cd9660_blksize(imp, ip, lbn); 395 396 if ((error = VOP_BMAP(vp, lbn, &devvp, &lbn, NULL)) != 0) { 397 *bpp = NULL; 398 return error; 399 } 400 if ((error = bread(devvp, lbn, bsize, 0, &bp)) != 0) { 401 *bpp = NULL; 402 return (error); 403 } 404 if (res) 405 *res = (char *)bp->b_data + cd9660_blkoff(imp, offset); 406 *bpp = bp; 407 return (0); 408} 409