| 1 | /* |
| 2 | * Copyright (c) 1989 The Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Copyright (c) 1983 Atsushi Murai (amurai@spec.co.jp) |
| 6 | * All rights reserved for Rock Ridge Extension Support. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. All advertising materials mentioning features or use of this software |
| 17 | * must display the following acknowledgement: |
| 18 | * This product includes software developed by the University of |
| 19 | * California, Berkeley and its contributors. |
| 20 | * 4. 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 | * $Id: isofs_lookup.c,v 1.4 1993/10/17 01:48:27 rgrimes Exp $ |
| 38 | */ |
| 39 | |
| 40 | #include "param.h" |
| 41 | #include "systm.h" |
| 42 | #include "namei.h" |
| 43 | #include "buf.h" |
| 44 | #include "file.h" |
| 45 | #include "vnode.h" |
| 46 | #include "mount.h" |
| 47 | |
| 48 | #include "iso.h" |
| 49 | #include "isofs_node.h" |
| 50 | #include "iso_rrip.h" |
| 51 | #include "isofs_rrip.h" |
| 52 | |
| 53 | struct nchstats nchstats; |
| 54 | |
| 55 | /* |
| 56 | * Convert a component of a pathname into a pointer to a locked inode. |
| 57 | * This is a very central and rather complicated routine. |
| 58 | * If the file system is not maintained in a strict tree hierarchy, |
| 59 | * this can result in a deadlock situation (see comments in code below). |
| 60 | * |
| 61 | * The flag argument is LOOKUP, CREATE, RENAME, or DELETE depending on |
| 62 | * whether the name is to be looked up, created, renamed, or deleted. |
| 63 | * When CREATE, RENAME, or DELETE is specified, information usable in |
| 64 | * creating, renaming, or deleting a directory entry may be calculated. |
| 65 | * If flag has LOCKPARENT or'ed into it and the target of the pathname |
| 66 | * exists, lookup returns both the target and its parent directory locked. |
| 67 | * When creating or renaming and LOCKPARENT is specified, the target may |
| 68 | * not be ".". When deleting and LOCKPARENT is specified, the target may |
| 69 | * be "."., but the caller must check to ensure it does an vrele and iput |
| 70 | * instead of two iputs. |
| 71 | * |
| 72 | * Overall outline of ufs_lookup: |
| 73 | * |
| 74 | * check accessibility of directory |
| 75 | * look for name in cache, if found, then if at end of path |
| 76 | * and deleting or creating, drop it, else return name |
| 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 | int |
| 91 | isofs_lookup(vdp, ndp, p) |
| 92 | register struct vnode *vdp; |
| 93 | register struct nameidata *ndp; |
| 94 | struct proc *p; |
| 95 | { |
| 96 | register struct iso_node *dp; /* the directory we are searching */ |
| 97 | register struct iso_mnt *imp; /* file system that directory is in */ |
| 98 | struct buf *bp = 0; /* a buffer of directory entries */ |
| 99 | register struct iso_directory_record *ep; |
| 100 | /* the current directory entry */ |
| 101 | int entryoffsetinblock = 0; /* offset of ep in bp's buffer */ |
| 102 | enum {NONE, COMPACT, FOUND} slotstatus; |
| 103 | int slotoffset = -1; /* offset of area with free space */ |
| 104 | int slotsize; /* size of area at slotoffset */ |
| 105 | int slotfreespace; /* amount of space free in slot */ |
| 106 | int slotneeded; /* size of the entry we're seeking */ |
| 107 | int numdirpasses; /* strategy for directory search */ |
| 108 | int endsearch; /* offset to end directory search */ |
| 109 | struct iso_node *pdp; /* saved dp during symlink work */ |
| 110 | struct iso_node *tdp; /* returned by iget */ |
| 111 | int flag; /* LOOKUP, CREATE, RENAME, or DELETE */ |
| 112 | int lockparent; /* 1 => lockparent flag is set */ |
| 113 | int wantparent; /* 1 => wantparent or lockparent flag */ |
| 114 | int error; |
| 115 | |
| 116 | int reclen; |
| 117 | int namelen; |
| 118 | char altname[251]; |
| 119 | int i; |
| 120 | |
| 121 | ndp->ni_dvp = vdp; |
| 122 | ndp->ni_vp = NULL; |
| 123 | dp = VTOI(vdp); |
| 124 | imp = dp->i_mnt; |
| 125 | lockparent = ndp->ni_nameiop & LOCKPARENT; |
| 126 | flag = ndp->ni_nameiop & OPMASK; |
| 127 | wantparent = ndp->ni_nameiop & (LOCKPARENT|WANTPARENT); |
| 128 | |
| 129 | /* |
| 130 | * Check accessiblity of directory. |
| 131 | */ |
| 132 | if ((dp->iso_flags & 2) == 0) |
| 133 | return (ENOTDIR); |
| 134 | |
| 135 | /* |
| 136 | * We now have a segment name to search for, and a directory to search. |
| 137 | * |
| 138 | * Before tediously performing a linear scan of the directory, |
| 139 | * check the name cache to see if the directory/name pair |
| 140 | * we are looking for is known already. |
| 141 | */ |
| 142 | if (error = cache_lookup(ndp)) { |
| 143 | int vpid; /* capability number of vnode */ |
| 144 | |
| 145 | if (error == ENOENT) |
| 146 | return (error); |
| 147 | #ifdef PARANOID |
| 148 | if (vdp == ndp->ni_rootdir && ndp->ni_isdotdot) |
| 149 | panic("ufs_lookup: .. through root"); |
| 150 | #endif |
| 151 | /* |
| 152 | * Get the next vnode in the path. |
| 153 | * See comment below starting `Step through' for |
| 154 | * an explaination of the locking protocol. |
| 155 | */ |
| 156 | pdp = dp; |
| 157 | dp = VTOI(ndp->ni_vp); |
| 158 | vdp = ndp->ni_vp; |
| 159 | vpid = vdp->v_id; |
| 160 | if (pdp == dp) { |
| 161 | VREF(vdp); |
| 162 | error = 0; |
| 163 | } else if (ndp->ni_isdotdot) { |
| 164 | ISO_IUNLOCK(pdp); |
| 165 | error = vget(vdp); |
| 166 | if (!error && lockparent && *ndp->ni_next == '\0') |
| 167 | ISO_ILOCK(pdp); |
| 168 | } else { |
| 169 | error = vget(vdp); |
| 170 | if (!lockparent || error || *ndp->ni_next != '\0') |
| 171 | ISO_IUNLOCK(pdp); |
| 172 | } |
| 173 | /* |
| 174 | * Check that the capability number did not change |
| 175 | * while we were waiting for the lock. |
| 176 | */ |
| 177 | if (!error) { |
| 178 | if (vpid == vdp->v_id) |
| 179 | return (0); |
| 180 | iso_iput(dp); |
| 181 | if (lockparent && pdp != dp && *ndp->ni_next == '\0') |
| 182 | ISO_IUNLOCK(pdp); |
| 183 | } |
| 184 | ISO_ILOCK(pdp); |
| 185 | dp = pdp; |
| 186 | vdp = ITOV(dp); |
| 187 | ndp->ni_vp = NULL; |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * If there is cached information on a previous search of |
| 192 | * this directory, pick up where we last left off. |
| 193 | * We cache only lookups as these are the most common |
| 194 | * and have the greatest payoff. Caching CREATE has little |
| 195 | * benefit as it usually must search the entire directory |
| 196 | * to determine that the entry does not exist. Caching the |
| 197 | * location of the last DELETE or RENAME has not reduced |
| 198 | * profiling time and hence has been removed in the interest |
| 199 | * of simplicity. |
| 200 | */ |
| 201 | if (flag != LOOKUP || dp->i_diroff == 0 || dp->i_diroff > dp->i_size) { |
| 202 | ndp->ni_ufs.ufs_offset = 0; |
| 203 | numdirpasses = 1; |
| 204 | } else { |
| 205 | ndp->ni_ufs.ufs_offset = dp->i_diroff; |
| 206 | entryoffsetinblock = iso_blkoff(imp, ndp->ni_ufs.ufs_offset); |
| 207 | if (entryoffsetinblock != 0) { |
| 208 | if (error = iso_blkatoff(dp, ndp->ni_ufs.ufs_offset, |
| 209 | (char **)0, &bp)) |
| 210 | return (error); |
| 211 | } |
| 212 | numdirpasses = 2; |
| 213 | nchstats.ncs_2passes++; |
| 214 | } |
| 215 | endsearch = roundup(dp->i_size, imp->logical_block_size); |
| 216 | |
| 217 | searchloop: |
| 218 | while (ndp->ni_ufs.ufs_offset < endsearch) { |
| 219 | /* |
| 220 | * If offset is on a block boundary, |
| 221 | * read the next directory block. |
| 222 | * Release previous if it exists. |
| 223 | */ |
| 224 | if (iso_blkoff(imp, ndp->ni_ufs.ufs_offset) == 0) { |
| 225 | if (bp != NULL) |
| 226 | brelse(bp); |
| 227 | if (error = iso_blkatoff(dp, ndp->ni_ufs.ufs_offset, |
| 228 | (char **)0, &bp)) |
| 229 | return (error); |
| 230 | entryoffsetinblock = 0; |
| 231 | } |
| 232 | /* |
| 233 | * Get pointer to next entry. |
| 234 | */ |
| 235 | |
| 236 | ep = (struct iso_directory_record *) |
| 237 | (bp->b_un.b_addr + entryoffsetinblock); |
| 238 | |
| 239 | reclen = isonum_711 (ep->length); |
| 240 | if (reclen == 0) { |
| 241 | /* skip to next block, if any */ |
| 242 | ndp->ni_ufs.ufs_offset = |
| 243 | roundup (ndp->ni_ufs.ufs_offset, |
| 244 | imp->logical_block_size); |
| 245 | continue; |
| 246 | } |
| 247 | |
| 248 | if (reclen < sizeof (struct iso_directory_record)) |
| 249 | /* illegal entry, stop */ |
| 250 | break; |
| 251 | |
| 252 | /* 10 Aug 92*/ if (entryoffsetinblock + reclen -1 >= imp->logical_block_size) |
| 253 | /* entries are not allowed to cross boundaries */ |
| 254 | break; |
| 255 | |
| 256 | /* |
| 257 | * Check for a name match. |
| 258 | */ |
| 259 | namelen = isonum_711 (ep->name_len); |
| 260 | |
| 261 | if (reclen < sizeof (struct iso_directory_record) + namelen) |
| 262 | /* illegal entry, stop */ |
| 263 | break; |
| 264 | |
| 265 | if (namelen == 1 |
| 266 | && ((ndp->ni_namelen == 1 |
| 267 | && ndp->ni_ptr[0] == '.' |
| 268 | && ep->name[0] == 0) |
| 269 | || (ndp->ni_isdotdot && ep->name[0] == 1))) { |
| 270 | /* |
| 271 | * Save directory entry's inode number and |
| 272 | * reclen in ndp->ni_ufs area, and release |
| 273 | * directory buffer. |
| 274 | */ |
| 275 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); |
| 276 | brelse(bp); |
| 277 | goto found; |
| 278 | } else { |
| 279 | switch ( imp->iso_ftype ) { |
| 280 | case ISO_FTYPE_9660: |
| 281 | if( ( namelen >= ndp->ni_namelen ) && |
| 282 | ( isofncmp( ndp->ni_ptr, ndp->ni_namelen, ep->name, namelen ) ) ) { |
| 283 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); |
| 284 | brelse(bp); |
| 285 | goto found; |
| 286 | } |
| 287 | break; |
| 288 | case ISO_FTYPE_RRIP: |
| 289 | isofs_rrip_getname( ep, altname, &namelen ); |
| 290 | if ( ( namelen == ndp->ni_namelen ) && |
| 291 | ( !bcmp( ndp->ni_ptr, altname, ndp->ni_namelen ) ) ) { |
| 292 | ndp->ni_ufs.ufs_ino = isonum_733 (ep->extent); |
| 293 | brelse(bp); |
| 294 | goto found; |
| 295 | } |
| 296 | break; |
| 297 | default: |
| 298 | break; |
| 299 | } |
| 300 | } |
| 301 | ndp->ni_ufs.ufs_offset += reclen; |
| 302 | entryoffsetinblock += reclen; |
| 303 | } |
| 304 | /* notfound: */ |
| 305 | /* |
| 306 | * If we started in the middle of the directory and failed |
| 307 | * to find our target, we must check the beginning as well. |
| 308 | */ |
| 309 | if (numdirpasses == 2) { |
| 310 | numdirpasses--; |
| 311 | ndp->ni_ufs.ufs_offset = 0; |
| 312 | endsearch = dp->i_diroff; |
| 313 | goto searchloop; |
| 314 | } |
| 315 | if (bp != NULL) |
| 316 | brelse(bp); |
| 317 | /* |
| 318 | * Insert name into cache (as non-existent) if appropriate. |
| 319 | */ |
| 320 | if (ndp->ni_makeentry) |
| 321 | cache_enter(ndp); |
| 322 | return (ENOENT); |
| 323 | |
| 324 | found: |
| 325 | if (numdirpasses == 2) |
| 326 | nchstats.ncs_pass2++; |
| 327 | |
| 328 | /* |
| 329 | * Found component in pathname. |
| 330 | * If the final component of path name, save information |
| 331 | * in the cache as to where the entry was found. |
| 332 | */ |
| 333 | if (*ndp->ni_next == '\0' && flag == LOOKUP) |
| 334 | dp->i_diroff = ndp->ni_ufs.ufs_offset; |
| 335 | /* &~ (imp->logical_block_size - 1); */ |
| 336 | |
| 337 | /* |
| 338 | * Step through the translation in the name. We do not `iput' the |
| 339 | * directory because we may need it again if a symbolic link |
| 340 | * is relative to the current directory. Instead we save it |
| 341 | * unlocked as "pdp". We must get the target inode before unlocking |
| 342 | * the directory to insure that the inode will not be removed |
| 343 | * before we get it. We prevent deadlock by always fetching |
| 344 | * inodes from the root, moving down the directory tree. Thus |
| 345 | * when following backward pointers ".." we must unlock the |
| 346 | * parent directory before getting the requested directory. |
| 347 | * There is a potential race condition here if both the current |
| 348 | * and parent directories are removed before the `iget' for the |
| 349 | * inode associated with ".." returns. We hope that this occurs |
| 350 | * infrequently since we cannot avoid this race condition without |
| 351 | * implementing a sophisticated deadlock detection algorithm. |
| 352 | * Note also that this simple deadlock detection scheme will not |
| 353 | * work if the file system has any hard links other than ".." |
| 354 | * that point backwards in the directory structure. |
| 355 | */ |
| 356 | pdp = dp; |
| 357 | if (ndp->ni_isdotdot) { |
| 358 | ISO_IUNLOCK(pdp); /* race to get the inode */ |
| 359 | if (error = iso_iget(dp, ndp->ni_ufs.ufs_ino, &tdp, ep)) { |
| 360 | ISO_ILOCK(pdp); |
| 361 | return (error); |
| 362 | } |
| 363 | if (lockparent && *ndp->ni_next == '\0') |
| 364 | ISO_ILOCK(pdp); |
| 365 | ndp->ni_vp = ITOV(tdp); |
| 366 | } else if (dp->i_number == ndp->ni_ufs.ufs_ino) { |
| 367 | VREF(vdp); /* we want ourself, ie "." */ |
| 368 | ndp->ni_vp = vdp; |
| 369 | } else { |
| 370 | if (error = iso_iget(dp, ndp->ni_ufs.ufs_ino, &tdp, ep)) |
| 371 | return (error); |
| 372 | if (!lockparent || *ndp->ni_next != '\0') |
| 373 | ISO_IUNLOCK(pdp); |
| 374 | ndp->ni_vp = ITOV(tdp); |
| 375 | } |
| 376 | |
| 377 | /* |
| 378 | * Insert name into cache if appropriate. |
| 379 | */ |
| 380 | if (ndp->ni_makeentry) |
| 381 | cache_enter(ndp); |
| 382 | return (0); |
| 383 | } |
| 384 | |
| 385 | |
| 386 | /* |
| 387 | * Return buffer with contents of block "offset" |
| 388 | * from the beginning of directory "ip". If "res" |
| 389 | * is non-zero, fill it in with a pointer to the |
| 390 | * remaining space in the directory. |
| 391 | */ |
| 392 | int |
| 393 | iso_blkatoff(ip, offset, res, bpp) |
| 394 | struct iso_node *ip; |
| 395 | off_t offset; |
| 396 | char **res; |
| 397 | struct buf **bpp; |
| 398 | { |
| 399 | register struct iso_mnt *imp = ip->i_mnt; |
| 400 | daddr_t lbn = iso_lblkno (imp, offset); |
| 401 | int bsize = iso_blksize (imp, ip, lbn); |
| 402 | struct buf *bp; |
| 403 | int error; |
| 404 | |
| 405 | *bpp = 0; |
| 406 | if (error = bread(ITOV(ip), lbn, bsize, NOCRED, &bp)) { |
| 407 | brelse(bp); |
| 408 | return (error); |
| 409 | } |
| 410 | if (res) |
| 411 | *res = bp->b_un.b_addr + iso_blkoff(imp, offset); |
| 412 | *bpp = bp; |
| 413 | |
| 414 | return (0); |
| 415 | } |