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sys/fs/ext2fs/ext2_lookup.c
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1 /*- 2 * modified for Lites 1.1 3 * 4 * Aug 1995, Godmar Back (gback@cs.utah.edu) 5 * University of Utah, Department of Computer Science 6 */ 7 /*- 8 * SPDX-License-Identifier: BSD-3-Clause 9 * 10 * Copyright (c) 1989, 1993 11 * The Regents of the University of California. All rights reserved. 12 * (c) UNIX System Laboratories, Inc. 13 * All or some portions of this file are derived from material licensed 14 * to the University of California by American Telephone and Telegraph 15 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 16 * the permission of UNIX System Laboratories, Inc. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94 43 * $FreeBSD$ 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/namei.h> 49 #include <sys/bio.h> 50 #include <sys/buf.h> 51 #include <sys/endian.h> 52 #include <sys/mount.h> 53 #include <sys/vnode.h> 54 #include <sys/malloc.h> 55 #include <sys/dirent.h> 56 #include <sys/sdt.h> 57 #include <sys/sysctl.h> 58 59 #include <ufs/ufs/dir.h> 60 61 #include <fs/ext2fs/fs.h> 62 #include <fs/ext2fs/inode.h> 63 #include <fs/ext2fs/ext2_mount.h> 64 #include <fs/ext2fs/ext2fs.h> 65 #include <fs/ext2fs/ext2_dinode.h> 66 #include <fs/ext2fs/ext2_dir.h> 67 #include <fs/ext2fs/ext2_extern.h> 68 #include <fs/ext2fs/fs.h> 69 70 SDT_PROVIDER_DECLARE(ext2fs); 71 /* 72 * ext2fs trace probe: 73 * arg0: verbosity. Higher numbers give more verbose messages 74 * arg1: Textual message 75 */ 76 SDT_PROBE_DEFINE2(ext2fs, , lookup, trace, "int", "char*"); 77 SDT_PROBE_DEFINE4(ext2fs, , trace, ext2_dirbad_error, 78 "char*", "ino_t", "doff_t", "char*"); 79 SDT_PROBE_DEFINE5(ext2fs, , trace, ext2_dirbadentry_error, 80 "char*", "int", "uint32_t", "uint16_t", "uint8_t"); 81 82 #ifdef INVARIANTS 83 static int dirchk = 1; 84 #else 85 static int dirchk = 0; 86 #endif 87 88 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 89 "EXT2FS filesystem"); 90 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, ""); 91 92 /* 93 DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512) 94 while it is the native blocksize in ext2fs - thus, a #define 95 is no longer appropriate 96 */ 97 #undef DIRBLKSIZ 98 99 static u_char ext2_ft_to_dt[] = { 100 DT_UNKNOWN, /* EXT2_FT_UNKNOWN */ 101 DT_REG, /* EXT2_FT_REG_FILE */ 102 DT_DIR, /* EXT2_FT_DIR */ 103 DT_CHR, /* EXT2_FT_CHRDEV */ 104 DT_BLK, /* EXT2_FT_BLKDEV */ 105 DT_FIFO, /* EXT2_FT_FIFO */ 106 DT_SOCK, /* EXT2_FT_SOCK */ 107 DT_LNK, /* EXT2_FT_SYMLINK */ 108 }; 109 #define FTTODT(ft) \ 110 ((ft) < nitems(ext2_ft_to_dt) ? ext2_ft_to_dt[(ft)] : DT_UNKNOWN) 111 112 static u_char dt_to_ext2_ft[] = { 113 EXT2_FT_UNKNOWN, /* DT_UNKNOWN */ 114 EXT2_FT_FIFO, /* DT_FIFO */ 115 EXT2_FT_CHRDEV, /* DT_CHR */ 116 EXT2_FT_UNKNOWN, /* unused */ 117 EXT2_FT_DIR, /* DT_DIR */ 118 EXT2_FT_UNKNOWN, /* unused */ 119 EXT2_FT_BLKDEV, /* DT_BLK */ 120 EXT2_FT_UNKNOWN, /* unused */ 121 EXT2_FT_REG_FILE, /* DT_REG */ 122 EXT2_FT_UNKNOWN, /* unused */ 123 EXT2_FT_SYMLINK, /* DT_LNK */ 124 EXT2_FT_UNKNOWN, /* unused */ 125 EXT2_FT_SOCK, /* DT_SOCK */ 126 EXT2_FT_UNKNOWN, /* unused */ 127 EXT2_FT_UNKNOWN, /* DT_WHT */ 128 }; 129 #define DTTOFT(dt) \ 130 ((dt) < nitems(dt_to_ext2_ft) ? dt_to_ext2_ft[(dt)] : EXT2_FT_UNKNOWN) 131 132 static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, 133 int entryoffsetinblock); 134 static int ext2_is_dot_entry(struct componentname *cnp); 135 static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, 136 struct componentname *cnp, ino_t *dd_ino); 137 138 static int 139 ext2_is_dot_entry(struct componentname *cnp) 140 { 141 if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' && 142 (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0')) 143 return (1); 144 return (0); 145 } 146 147 /* 148 * Vnode op for reading directories. 149 */ 150 int 151 ext2_readdir(struct vop_readdir_args *ap) 152 { 153 struct vnode *vp = ap->a_vp; 154 struct uio *uio = ap->a_uio; 155 struct buf *bp; 156 struct inode *ip; 157 struct ext2fs_direct_2 *dp, *edp; 158 u_long *cookies; 159 struct dirent dstdp; 160 off_t offset, startoffset; 161 size_t readcnt, skipcnt; 162 ssize_t startresid; 163 u_int ncookies; 164 int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize; 165 int error; 166 167 if (uio->uio_offset < 0) 168 return (EINVAL); 169 ip = VTOI(vp); 170 if (ap->a_ncookies != NULL) { 171 if (uio->uio_resid < 0) 172 ncookies = 0; 173 else 174 ncookies = uio->uio_resid; 175 if (uio->uio_offset >= ip->i_size) 176 ncookies = 0; 177 else if (ip->i_size - uio->uio_offset < ncookies) 178 ncookies = ip->i_size - uio->uio_offset; 179 ncookies = ncookies / (offsetof(struct ext2fs_direct_2, 180 e2d_namlen) + 4) + 1; 181 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK); 182 *ap->a_ncookies = ncookies; 183 *ap->a_cookies = cookies; 184 } else { 185 ncookies = 0; 186 cookies = NULL; 187 } 188 offset = startoffset = uio->uio_offset; 189 startresid = uio->uio_resid; 190 error = 0; 191 while (error == 0 && uio->uio_resid > 0 && 192 uio->uio_offset < ip->i_size) { 193 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp); 194 if (error) 195 break; 196 if (bp->b_offset + bp->b_bcount > ip->i_size) 197 readcnt = ip->i_size - bp->b_offset; 198 else 199 readcnt = bp->b_bcount; 200 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) & 201 ~(size_t)(DIRBLKSIZ - 1); 202 offset = bp->b_offset + skipcnt; 203 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt]; 204 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt]; 205 while (error == 0 && uio->uio_resid > 0 && dp < edp) { 206 if (le16toh(dp->e2d_reclen) <= offsetof(struct ext2fs_direct_2, 207 e2d_namlen) || (caddr_t)dp + le16toh(dp->e2d_reclen) > 208 (caddr_t)edp) { 209 error = EIO; 210 break; 211 } 212 /*- 213 * "New" ext2fs directory entries differ in 3 ways 214 * from ufs on-disk ones: 215 * - the name is not necessarily NUL-terminated. 216 * - the file type field always exists and always 217 * follows the name length field. 218 * - the file type is encoded in a different way. 219 * 220 * "Old" ext2fs directory entries need no special 221 * conversions, since they are binary compatible 222 * with "new" entries having a file type of 0 (i.e., 223 * EXT2_FT_UNKNOWN). Splitting the old name length 224 * field didn't make a mess like it did in ufs, 225 * because ext2fs uses a machine-independent disk 226 * layout. 227 */ 228 dstdp.d_namlen = dp->e2d_namlen; 229 dstdp.d_type = FTTODT(dp->e2d_type); 230 if (offsetof(struct ext2fs_direct_2, e2d_namlen) + 231 dstdp.d_namlen > le16toh(dp->e2d_reclen)) { 232 error = EIO; 233 break; 234 } 235 if (offset < startoffset || le32toh(dp->e2d_ino) == 0) 236 goto nextentry; 237 dstdp.d_fileno = le32toh(dp->e2d_ino); 238 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp); 239 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen); 240 /* NOTE: d_off is the offset of the *next* entry. */ 241 dstdp.d_off = offset + le16toh(dp->e2d_reclen); 242 dirent_terminate(&dstdp); 243 if (dstdp.d_reclen > uio->uio_resid) { 244 if (uio->uio_resid == startresid) 245 error = EINVAL; 246 else 247 error = EJUSTRETURN; 248 break; 249 } 250 /* Advance dp. */ 251 error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio); 252 if (error) 253 break; 254 if (cookies != NULL) { 255 KASSERT(ncookies > 0, 256 ("ext2_readdir: cookies buffer too small")); 257 *cookies = offset + le16toh(dp->e2d_reclen); 258 cookies++; 259 ncookies--; 260 } 261 nextentry: 262 offset += le16toh(dp->e2d_reclen); 263 dp = (struct ext2fs_direct_2 *)((caddr_t)dp + 264 le16toh(dp->e2d_reclen)); 265 } 266 bqrelse(bp); 267 uio->uio_offset = offset; 268 } 269 /* We need to correct uio_offset. */ 270 uio->uio_offset = offset; 271 if (error == EJUSTRETURN) 272 error = 0; 273 if (ap->a_ncookies != NULL) { 274 if (error == 0) { 275 ap->a_ncookies -= ncookies; 276 } else { 277 free(*ap->a_cookies, M_TEMP); 278 *ap->a_ncookies = 0; 279 *ap->a_cookies = NULL; 280 } 281 } 282 if (error == 0 && ap->a_eofflag) 283 *ap->a_eofflag = ip->i_size <= uio->uio_offset; 284 return (error); 285 } 286 287 /* 288 * Convert a component of a pathname into a pointer to a locked inode. 289 * This is a very central and rather complicated routine. 290 * If the file system is not maintained in a strict tree hierarchy, 291 * this can result in a deadlock situation (see comments in code below). 292 * 293 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending 294 * on whether the name is to be looked up, created, renamed, or deleted. 295 * When CREATE, RENAME, or DELETE is specified, information usable in 296 * creating, renaming, or deleting a directory entry may be calculated. 297 * If flag has LOCKPARENT or'ed into it and the target of the pathname 298 * exists, lookup returns both the target and its parent directory locked. 299 * When creating or renaming and LOCKPARENT is specified, the target may 300 * not be ".". When deleting and LOCKPARENT is specified, the target may 301 * be "."., but the caller must check to ensure it does an vrele and vput 302 * instead of two vputs. 303 * 304 * Overall outline of ext2_lookup: 305 * 306 * search for name in directory, to found or notfound 307 * notfound: 308 * if creating, return locked directory, leaving info on available slots 309 * else return error 310 * found: 311 * if at end of path and deleting, return information to allow delete 312 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 313 * inode and return info to allow rewrite 314 * if not at end, add name to cache; if at end and neither creating 315 * nor deleting, add name to cache 316 */ 317 int 318 ext2_lookup(struct vop_cachedlookup_args *ap) 319 { 320 321 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); 322 } 323 324 static int 325 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, 326 ino_t *dd_ino) 327 { 328 struct inode *dp; /* inode for directory being searched */ 329 struct buf *bp; /* a buffer of directory entries */ 330 struct ext2fs_direct_2 *ep; /* the current directory entry */ 331 int entryoffsetinblock; /* offset of ep in bp's buffer */ 332 struct ext2fs_searchslot ss; 333 doff_t i_diroff; /* cached i_diroff value */ 334 doff_t i_offset; /* cached i_offset value */ 335 int numdirpasses; /* strategy for directory search */ 336 doff_t endsearch; /* offset to end directory search */ 337 doff_t prevoff; /* prev entry dp->i_offset */ 338 struct vnode *pdp; /* saved dp during symlink work */ 339 struct vnode *tdp; /* returned by VFS_VGET */ 340 doff_t enduseful; /* pointer past last used dir slot */ 341 u_long bmask; /* block offset mask */ 342 int error; 343 struct ucred *cred = cnp->cn_cred; 344 int flags = cnp->cn_flags; 345 int nameiop = cnp->cn_nameiop; 346 ino_t ino, ino1; 347 int ltype; 348 int entry_found = 0; 349 350 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize; 351 352 if (vpp != NULL) 353 *vpp = NULL; 354 355 dp = VTOI(vdp); 356 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 357 restart: 358 bp = NULL; 359 ss.slotoffset = -1; 360 361 /* 362 * We now have a segment name to search for, and a directory to search. 363 * 364 * Suppress search for slots unless creating 365 * file and at end of pathname, in which case 366 * we watch for a place to put the new file in 367 * case it doesn't already exist. 368 */ 369 i_diroff = dp->i_diroff; 370 ss.slotstatus = FOUND; 371 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0; 372 if ((nameiop == CREATE || nameiop == RENAME) && 373 (flags & ISLASTCN)) { 374 ss.slotstatus = NONE; 375 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen); 376 /* 377 * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN + 378 * cnp->cn_namelen + 3) &~ 3; 379 */ 380 } 381 /* 382 * Try to lookup dir entry using htree directory index. 383 * 384 * If we got an error or we want to find '.' or '..' entry, 385 * we will fall back to linear search. 386 */ 387 if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) { 388 numdirpasses = 1; 389 entryoffsetinblock = 0; 390 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, 391 &bp, &entryoffsetinblock, &i_offset, &prevoff, 392 &enduseful, &ss)) { 393 case 0: 394 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data + 395 (i_offset & bmask)); 396 goto foundentry; 397 case ENOENT: 398 i_offset = roundup2(dp->i_size, DIRBLKSIZ); 399 goto notfound; 400 default: 401 /* 402 * Something failed; just fallback to do a linear 403 * search. 404 */ 405 break; 406 } 407 } 408 409 /* 410 * If there is cached information on a previous search of 411 * this directory, pick up where we last left off. 412 * We cache only lookups as these are the most common 413 * and have the greatest payoff. Caching CREATE has little 414 * benefit as it usually must search the entire directory 415 * to determine that the entry does not exist. Caching the 416 * location of the last DELETE or RENAME has not reduced 417 * profiling time and hence has been removed in the interest 418 * of simplicity. 419 */ 420 if (nameiop != LOOKUP || i_diroff == 0 || 421 i_diroff > dp->i_size) { 422 entryoffsetinblock = 0; 423 i_offset = 0; 424 numdirpasses = 1; 425 } else { 426 i_offset = i_diroff; 427 if ((entryoffsetinblock = i_offset & bmask) && 428 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, 429 &bp))) 430 return (error); 431 numdirpasses = 2; 432 nchstats.ncs_2passes++; 433 } 434 prevoff = i_offset; 435 endsearch = roundup2(dp->i_size, DIRBLKSIZ); 436 enduseful = 0; 437 438 searchloop: 439 while (i_offset < endsearch) { 440 /* 441 * If necessary, get the next directory block. 442 */ 443 if (bp != NULL) 444 brelse(bp); 445 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp); 446 if (error != 0) 447 return (error); 448 449 entryoffsetinblock = 0; 450 if (ss.slotstatus == NONE) { 451 ss.slotoffset = -1; 452 ss.slotfreespace = 0; 453 } 454 455 error = ext2_search_dirblock(dp, bp->b_data, &entry_found, 456 cnp->cn_nameptr, cnp->cn_namelen, 457 &entryoffsetinblock, &i_offset, &prevoff, 458 &enduseful, &ss); 459 if (error != 0) { 460 brelse(bp); 461 return (error); 462 } 463 if (entry_found) { 464 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data + 465 (entryoffsetinblock & bmask)); 466 foundentry: 467 ino = le32toh(ep->e2d_ino); 468 goto found; 469 } 470 } 471 notfound: 472 /* 473 * If we started in the middle of the directory and failed 474 * to find our target, we must check the beginning as well. 475 */ 476 if (numdirpasses == 2) { 477 numdirpasses--; 478 i_offset = 0; 479 endsearch = i_diroff; 480 goto searchloop; 481 } 482 if (bp != NULL) 483 brelse(bp); 484 /* 485 * If creating, and at end of pathname and current 486 * directory has not been removed, then can consider 487 * allowing file to be created. 488 */ 489 if ((nameiop == CREATE || nameiop == RENAME) && 490 (flags & ISLASTCN) && dp->i_nlink != 0) { 491 /* 492 * Access for write is interpreted as allowing 493 * creation of files in the directory. 494 */ 495 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 496 return (error); 497 /* 498 * Return an indication of where the new directory 499 * entry should be put. If we didn't find a slot, 500 * then set dp->i_count to 0 indicating 501 * that the new slot belongs at the end of the 502 * directory. If we found a slot, then the new entry 503 * can be put in the range from dp->i_offset to 504 * dp->i_offset + dp->i_count. 505 */ 506 if (ss.slotstatus == NONE) { 507 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ); 508 dp->i_count = 0; 509 enduseful = dp->i_offset; 510 } else { 511 dp->i_offset = ss.slotoffset; 512 dp->i_count = ss.slotsize; 513 if (enduseful < ss.slotoffset + ss.slotsize) 514 enduseful = ss.slotoffset + ss.slotsize; 515 } 516 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ); 517 /* 518 * We return with the directory locked, so that 519 * the parameters we set up above will still be 520 * valid if we actually decide to do a direnter(). 521 * We return ni_vp == NULL to indicate that the entry 522 * does not currently exist; we leave a pointer to 523 * the (locked) directory inode in ndp->ni_dvp. 524 * The pathname buffer is saved so that the name 525 * can be obtained later. 526 * 527 * NB - if the directory is unlocked, then this 528 * information cannot be used. 529 */ 530 cnp->cn_flags |= SAVENAME; 531 return (EJUSTRETURN); 532 } 533 /* 534 * Insert name into cache (as non-existent) if appropriate. 535 */ 536 if ((cnp->cn_flags & MAKEENTRY) != 0) 537 cache_enter(vdp, NULL, cnp); 538 return (ENOENT); 539 540 found: 541 if (dd_ino != NULL) 542 *dd_ino = ino; 543 if (numdirpasses == 2) 544 nchstats.ncs_pass2++; 545 /* 546 * Check that directory length properly reflects presence 547 * of this entry. 548 */ 549 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) > 550 dp->i_size) { 551 ext2_dirbad(dp, i_offset, "i_size too small"); 552 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen); 553 dp->i_flag |= IN_CHANGE | IN_UPDATE; 554 } 555 brelse(bp); 556 557 /* 558 * Found component in pathname. 559 * If the final component of path name, save information 560 * in the cache as to where the entry was found. 561 */ 562 if ((flags & ISLASTCN) && nameiop == LOOKUP) 563 dp->i_diroff = rounddown2(i_offset, DIRBLKSIZ); 564 /* 565 * If deleting, and at end of pathname, return 566 * parameters which can be used to remove file. 567 */ 568 if (nameiop == DELETE && (flags & ISLASTCN)) { 569 if (flags & LOCKPARENT) 570 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__); 571 /* 572 * Write access to directory required to delete files. 573 */ 574 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 575 return (error); 576 /* 577 * Return pointer to current entry in dp->i_offset, 578 * and distance past previous entry (if there 579 * is a previous entry in this block) in dp->i_count. 580 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 581 * 582 * Technically we shouldn't be setting these in the 583 * WANTPARENT case (first lookup in rename()), but any 584 * lookups that will result in directory changes will 585 * overwrite these. 586 */ 587 dp->i_offset = i_offset; 588 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) 589 dp->i_count = 0; 590 else 591 dp->i_count = dp->i_offset - prevoff; 592 if (dd_ino != NULL) 593 return (0); 594 if (dp->i_number == ino) { 595 VREF(vdp); 596 *vpp = vdp; 597 return (0); 598 } 599 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 600 &tdp)) != 0) 601 return (error); 602 /* 603 * If directory is "sticky", then user must own 604 * the directory, or the file in it, else she 605 * may not delete it (unless she's root). This 606 * implements append-only directories. 607 */ 608 if ((dp->i_mode & ISVTX) && 609 cred->cr_uid != 0 && 610 cred->cr_uid != dp->i_uid && 611 VTOI(tdp)->i_uid != cred->cr_uid) { 612 vput(tdp); 613 return (EPERM); 614 } 615 *vpp = tdp; 616 return (0); 617 } 618 619 /* 620 * If rewriting (RENAME), return the inode and the 621 * information required to rewrite the present directory 622 * Must get inode of directory entry to verify it's a 623 * regular file, or empty directory. 624 */ 625 if (nameiop == RENAME && (flags & ISLASTCN)) { 626 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 627 return (error); 628 /* 629 * Careful about locking second inode. 630 * This can only occur if the target is ".". 631 */ 632 dp->i_offset = i_offset; 633 if (dp->i_number == ino) 634 return (EISDIR); 635 if (dd_ino != NULL) 636 return (0); 637 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 638 &tdp)) != 0) 639 return (error); 640 *vpp = tdp; 641 cnp->cn_flags |= SAVENAME; 642 return (0); 643 } 644 if (dd_ino != NULL) 645 return (0); 646 647 /* 648 * Step through the translation in the name. We do not `vput' the 649 * directory because we may need it again if a symbolic link 650 * is relative to the current directory. Instead we save it 651 * unlocked as "pdp". We must get the target inode before unlocking 652 * the directory to insure that the inode will not be removed 653 * before we get it. We prevent deadlock by always fetching 654 * inodes from the root, moving down the directory tree. Thus 655 * when following backward pointers ".." we must unlock the 656 * parent directory before getting the requested directory. 657 * There is a potential race condition here if both the current 658 * and parent directories are removed before the VFS_VGET for the 659 * inode associated with ".." returns. We hope that this occurs 660 * infrequently since we cannot avoid this race condition without 661 * implementing a sophisticated deadlock detection algorithm. 662 * Note also that this simple deadlock detection scheme will not 663 * work if the file system has any hard links other than ".." 664 * that point backwards in the directory structure. 665 */ 666 pdp = vdp; 667 if (flags & ISDOTDOT) { 668 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp); 669 if (VN_IS_DOOMED(pdp)) { 670 if (error == 0) 671 vput(tdp); 672 error = ENOENT; 673 } 674 if (error) 675 return (error); 676 /* 677 * Recheck that ".." entry in the vdp directory points 678 * to the inode we looked up before vdp lock was 679 * dropped. 680 */ 681 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1); 682 if (error) { 683 vput(tdp); 684 return (error); 685 } 686 if (ino1 != ino) { 687 vput(tdp); 688 goto restart; 689 } 690 *vpp = tdp; 691 } else if (dp->i_number == ino) { 692 VREF(vdp); /* we want ourself, ie "." */ 693 /* 694 * When we lookup "." we still can be asked to lock it 695 * differently. 696 */ 697 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 698 if (ltype != VOP_ISLOCKED(vdp)) { 699 if (ltype == LK_EXCLUSIVE) 700 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 701 else /* if (ltype == LK_SHARED) */ 702 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 703 } 704 *vpp = vdp; 705 } else { 706 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags, 707 &tdp)) != 0) 708 return (error); 709 *vpp = tdp; 710 } 711 712 /* 713 * Insert name into cache if appropriate. 714 */ 715 if (cnp->cn_flags & MAKEENTRY) 716 cache_enter(vdp, *vpp, cnp); 717 return (0); 718 } 719 720 int 721 ext2_search_dirblock(struct inode *ip, void *data, int *foundp, 722 const char *name, int namelen, int *entryoffsetinblockp, 723 doff_t *offp, doff_t *prevoffp, doff_t *endusefulp, 724 struct ext2fs_searchslot *ssp) 725 { 726 struct vnode *vdp; 727 struct ext2fs_direct_2 *ep, *top; 728 uint32_t bsize = ip->i_e2fs->e2fs_bsize; 729 int offset = *entryoffsetinblockp; 730 int namlen; 731 732 vdp = ITOV(ip); 733 734 ep = (struct ext2fs_direct_2 *)((char *)data + offset); 735 top = (struct ext2fs_direct_2 *)((char *)data + bsize); 736 while (ep < top) { 737 /* 738 * Full validation checks are slow, so we only check 739 * enough to insure forward progress through the 740 * directory. Complete checks can be run by setting 741 * "vfs.e2fs.dirchk" to be true. 742 */ 743 if (le16toh(ep->e2d_reclen) == 0 || 744 (dirchk && ext2_dirbadentry(vdp, ep, offset))) { 745 int i; 746 747 ext2_dirbad(ip, *offp, "mangled entry"); 748 i = bsize - (offset & (bsize - 1)); 749 *offp += i; 750 offset += i; 751 continue; 752 } 753 754 /* 755 * If an appropriate sized slot has not yet been found, 756 * check to see if one is available. Also accumulate space 757 * in the current block so that we can determine if 758 * compaction is viable. 759 */ 760 if (ssp->slotstatus != FOUND) { 761 int size = le16toh(ep->e2d_reclen); 762 763 if (ep->e2d_ino != 0) 764 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen); 765 else if (ext2_is_dirent_tail(ip, ep)) 766 size -= sizeof(struct ext2fs_direct_tail); 767 if (size > 0) { 768 if (size >= ssp->slotneeded) { 769 ssp->slotstatus = FOUND; 770 ssp->slotoffset = *offp; 771 ssp->slotsize = le16toh(ep->e2d_reclen); 772 } else if (ssp->slotstatus == NONE) { 773 ssp->slotfreespace += size; 774 if (ssp->slotoffset == -1) 775 ssp->slotoffset = *offp; 776 if (ssp->slotfreespace >= ssp->slotneeded) { 777 ssp->slotstatus = COMPACT; 778 ssp->slotsize = *offp + 779 le16toh(ep->e2d_reclen) - 780 ssp->slotoffset; 781 } 782 } 783 } 784 } 785 /* 786 * Check for a name match. 787 */ 788 if (ep->e2d_ino != 0) { 789 namlen = ep->e2d_namlen; 790 if (namlen == namelen && 791 !bcmp(name, ep->e2d_name, (unsigned)namlen)) { 792 /* 793 * Save directory entry's inode number and 794 * reclen in ndp->ni_ufs area, and release 795 * directory buffer. 796 */ 797 *foundp = 1; 798 return (0); 799 } 800 } 801 *prevoffp = *offp; 802 *offp += le16toh(ep->e2d_reclen); 803 offset += le16toh(ep->e2d_reclen); 804 *entryoffsetinblockp = offset; 805 if (ep->e2d_ino != 0) 806 *endusefulp = *offp; 807 /* 808 * Get pointer to the next entry. 809 */ 810 ep = (struct ext2fs_direct_2 *)((char *)data + offset); 811 } 812 813 return (0); 814 } 815 816 void 817 ext2_dirbad(struct inode *ip, doff_t offset, char *how) 818 { 819 struct mount *mp; 820 821 mp = ITOV(ip)->v_mount; 822 if ((mp->mnt_flag & MNT_RDONLY) == 0) 823 panic("ext2_dirbad: %s: bad dir ino %ju at offset %ld: %s\n", 824 mp->mnt_stat.f_mntonname, (uintmax_t)ip->i_number, 825 (long)offset, how); 826 else 827 SDT_PROBE4(ext2fs, , trace, ext2_dirbad_error, 828 mp->mnt_stat.f_mntonname, ip->i_number, offset, how); 829 } 830 831 /* 832 * Do consistency checking on a directory entry: 833 * record length must be multiple of 4 834 * entry must fit in rest of its DIRBLKSIZ block 835 * record must be large enough to contain entry 836 * name is not longer than MAXNAMLEN 837 * name must be as long as advertised, and null terminated 838 */ 839 /* 840 * changed so that it confirms to ext2_check_dir_entry 841 */ 842 static int 843 ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, 844 int entryoffsetinblock) 845 { 846 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize; 847 848 char *error_msg = NULL; 849 850 if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(1)) 851 error_msg = "rec_len is smaller than minimal"; 852 else if (le16toh(de->e2d_reclen) % 4 != 0) 853 error_msg = "rec_len % 4 != 0"; 854 else if (le16toh(de->e2d_reclen) < EXT2_DIR_REC_LEN(de->e2d_namlen)) 855 error_msg = "reclen is too small for name_len"; 856 else if (entryoffsetinblock + le16toh(de->e2d_reclen)> DIRBLKSIZ) 857 error_msg = "directory entry across blocks"; 858 /* else LATER 859 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count) 860 error_msg = "inode out of bounds"; 861 */ 862 863 if (error_msg != NULL) { 864 SDT_PROBE5(ext2fs, , trace, ext2_dirbadentry_error, 865 error_msg, entryoffsetinblock, 866 le32toh(de->e2d_ino), le16toh(de->e2d_reclen), 867 de->e2d_namlen); 868 } 869 return (error_msg == NULL ? 0 : 1); 870 } 871 872 /* 873 * Insert an entry into the fresh directory block. 874 * Initialize entry tail if the metadata_csum feature is turned on. 875 */ 876 static int 877 ext2_add_first_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry, 878 struct componentname *cnp) 879 { 880 struct inode *dp; 881 struct iovec aiov; 882 struct uio auio; 883 char* buf = NULL; 884 int dirblksize, error; 885 886 dp = VTOI(dvp); 887 dirblksize = dp->i_e2fs->e2fs_bsize; 888 889 if (dp->i_offset & (dirblksize - 1)) 890 panic("ext2_add_first_entry: bad directory offset"); 891 892 if (EXT2_HAS_RO_COMPAT_FEATURE(dp->i_e2fs, 893 EXT2F_ROCOMPAT_METADATA_CKSUM)) { 894 entry->e2d_reclen = htole16(dirblksize - 895 sizeof(struct ext2fs_direct_tail)); 896 buf = malloc(dirblksize, M_TEMP, M_WAITOK); 897 memcpy(buf, entry, EXT2_DIR_REC_LEN(entry->e2d_namlen)); 898 ext2_init_dirent_tail(EXT2_DIRENT_TAIL(buf, dirblksize)); 899 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)buf); 900 901 auio.uio_offset = dp->i_offset; 902 auio.uio_resid = dirblksize; 903 aiov.iov_len = auio.uio_resid; 904 aiov.iov_base = (caddr_t)buf; 905 } else { 906 entry->e2d_reclen = htole16(dirblksize); 907 auio.uio_offset = dp->i_offset; 908 auio.uio_resid = EXT2_DIR_REC_LEN(entry->e2d_namlen); 909 aiov.iov_len = auio.uio_resid; 910 aiov.iov_base = (caddr_t)entry; 911 } 912 913 auio.uio_iov = &aiov; 914 auio.uio_iovcnt = 1; 915 auio.uio_rw = UIO_WRITE; 916 auio.uio_segflg = UIO_SYSSPACE; 917 auio.uio_td = (struct thread *)0; 918 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred); 919 if (error) 920 goto out; 921 922 dp->i_size = roundup2(dp->i_size, dirblksize); 923 dp->i_flag |= IN_CHANGE; 924 925 out: 926 free(buf, M_TEMP); 927 return (error); 928 929 } 930 931 /* 932 * Write a directory entry after a call to namei, using the parameters 933 * that it left in nameidata. The argument ip is the inode which the new 934 * directory entry will refer to. Dvp is a pointer to the directory to 935 * be written, which was left locked by namei. Remaining parameters 936 * (dp->i_offset, dp->i_count) indicate how the space for the new 937 * entry is to be obtained. 938 */ 939 int 940 ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp) 941 { 942 struct inode *dp; 943 struct ext2fs_direct_2 newdir; 944 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize; 945 int error; 946 947 #ifdef INVARIANTS 948 if ((cnp->cn_flags & SAVENAME) == 0) 949 panic("ext2_direnter: missing name"); 950 #endif 951 dp = VTOI(dvp); 952 newdir.e2d_ino = htole32(ip->i_number); 953 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 954 EXT2F_INCOMPAT_FTYPE)) { 955 newdir.e2d_namlen = cnp->cn_namelen; 956 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode)); 957 } else 958 newdir.e2d_namlen = htole16(cnp->cn_namelen); 959 960 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1); 961 962 if (ext2_htree_has_idx(dp)) { 963 error = ext2_htree_add_entry(dvp, &newdir, cnp); 964 if (error) { 965 dp->i_flag &= ~IN_E3INDEX; 966 dp->i_flag |= IN_CHANGE | IN_UPDATE; 967 } 968 return (error); 969 } 970 971 if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) && 972 !ext2_htree_has_idx(dp)) { 973 if ((dp->i_size / DIRBLKSIZ) == 1 && 974 dp->i_offset == DIRBLKSIZ) { 975 /* 976 * Making indexed directory when one block is not 977 * enough to save all entries. 978 */ 979 return ext2_htree_create_index(dvp, cnp, &newdir); 980 } 981 } 982 983 /* 984 * If dp->i_count is 0, then namei could find no 985 * space in the directory. Here, dp->i_offset will 986 * be on a directory block boundary and we will write the 987 * new entry into a fresh block. 988 */ 989 if (dp->i_count == 0) 990 return ext2_add_first_entry(dvp, &newdir, cnp); 991 992 error = ext2_add_entry(dvp, &newdir); 993 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size) 994 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC, 995 cnp->cn_cred, cnp->cn_thread); 996 return (error); 997 } 998 999 /* 1000 * Insert an entry into the directory block. 1001 * Compact the contents. 1002 */ 1003 int 1004 ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry) 1005 { 1006 struct ext2fs_direct_2 *ep, *nep; 1007 struct inode *dp; 1008 struct buf *bp; 1009 u_int dsize; 1010 int error, loc, newentrysize, spacefree; 1011 char *dirbuf; 1012 1013 dp = VTOI(dvp); 1014 1015 /* 1016 * If dp->i_count is non-zero, then namei found space 1017 * for the new entry in the range dp->i_offset to 1018 * dp->i_offset + dp->i_count in the directory. 1019 * To use this space, we may have to compact the entries located 1020 * there, by copying them together towards the beginning of the 1021 * block, leaving the free space in one usable chunk at the end. 1022 */ 1023 1024 /* 1025 * Increase size of directory if entry eats into new space. 1026 * This should never push the size past a new multiple of 1027 * DIRBLKSIZE. 1028 * 1029 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. 1030 */ 1031 if (dp->i_offset + dp->i_count > dp->i_size) 1032 dp->i_size = dp->i_offset + dp->i_count; 1033 /* 1034 * Get the block containing the space for the new directory entry. 1035 */ 1036 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf, 1037 &bp)) != 0) 1038 return (error); 1039 /* 1040 * Find space for the new entry. In the simple case, the entry at 1041 * offset base will have the space. If it does not, then namei 1042 * arranged that compacting the region dp->i_offset to 1043 * dp->i_offset + dp->i_count would yield the 1044 * space. 1045 */ 1046 newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen); 1047 ep = (struct ext2fs_direct_2 *)dirbuf; 1048 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen); 1049 spacefree = le16toh(ep->e2d_reclen) - dsize; 1050 for (loc = le16toh(ep->e2d_reclen); loc < dp->i_count; ) { 1051 nep = (struct ext2fs_direct_2 *)(dirbuf + loc); 1052 if (le32toh(ep->e2d_ino)) { 1053 /* trim the existing slot */ 1054 ep->e2d_reclen = htole16(dsize); 1055 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 1056 } else { 1057 /* overwrite; nothing there; header is ours */ 1058 spacefree += dsize; 1059 } 1060 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen); 1061 spacefree += le16toh(nep->e2d_reclen) - dsize; 1062 loc += le16toh(nep->e2d_reclen); 1063 bcopy((caddr_t)nep, (caddr_t)ep, dsize); 1064 } 1065 /* 1066 * Update the pointer fields in the previous entry (if any), 1067 * copy in the new entry, and write out the block. 1068 */ 1069 if (ep->e2d_ino == 0) { 1070 if (spacefree + dsize < newentrysize) 1071 panic("ext2_direnter: compact1"); 1072 entry->e2d_reclen = htole16(spacefree + dsize); 1073 } else { 1074 if (spacefree < newentrysize) 1075 panic("ext2_direnter: compact2"); 1076 entry->e2d_reclen = htole16(spacefree); 1077 ep->e2d_reclen = htole16(dsize); 1078 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 1079 } 1080 bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize); 1081 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data); 1082 if (DOINGASYNC(dvp)) { 1083 bdwrite(bp); 1084 error = 0; 1085 } else { 1086 error = bwrite(bp); 1087 } 1088 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1089 return (error); 1090 } 1091 1092 /* 1093 * Remove a directory entry after a call to namei, using 1094 * the parameters which it left in nameidata. The entry 1095 * dp->i_offset contains the offset into the directory of the 1096 * entry to be eliminated. The dp->i_count field contains the 1097 * size of the previous record in the directory. If this 1098 * is 0, the first entry is being deleted, so we need only 1099 * zero the inode number to mark the entry as free. If the 1100 * entry is not the first in the directory, we must reclaim 1101 * the space of the now empty record by adding the record size 1102 * to the size of the previous entry. 1103 */ 1104 int 1105 ext2_dirremove(struct vnode *dvp, struct componentname *cnp) 1106 { 1107 struct inode *dp; 1108 struct ext2fs_direct_2 *ep, *rep; 1109 struct buf *bp; 1110 int error; 1111 1112 dp = VTOI(dvp); 1113 if (dp->i_count == 0) { 1114 /* 1115 * First entry in block: set d_ino to zero. 1116 */ 1117 if ((error = 1118 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep, 1119 &bp)) != 0) 1120 return (error); 1121 ep->e2d_ino = 0; 1122 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data); 1123 error = bwrite(bp); 1124 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1125 return (error); 1126 } 1127 /* 1128 * Collapse new free space into previous entry. 1129 */ 1130 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count), 1131 (char **)&ep, &bp)) != 0) 1132 return (error); 1133 1134 /* Set 'rep' to the entry being removed. */ 1135 if (dp->i_count == 0) 1136 rep = ep; 1137 else 1138 rep = (struct ext2fs_direct_2 *)((char *)ep + 1139 le16toh(ep->e2d_reclen)); 1140 ep->e2d_reclen += rep->e2d_reclen; 1141 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data); 1142 if (DOINGASYNC(dvp) && dp->i_count != 0) 1143 bdwrite(bp); 1144 else 1145 error = bwrite(bp); 1146 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1147 return (error); 1148 } 1149 1150 /* 1151 * Rewrite an existing directory entry to point at the inode 1152 * supplied. The parameters describing the directory entry are 1153 * set up by a call to namei. 1154 */ 1155 int 1156 ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp) 1157 { 1158 struct buf *bp; 1159 struct ext2fs_direct_2 *ep; 1160 struct vnode *vdp = ITOV(dp); 1161 int error; 1162 1163 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep, 1164 &bp)) != 0) 1165 return (error); 1166 ep->e2d_ino = htole32(ip->i_number); 1167 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 1168 EXT2F_INCOMPAT_FTYPE)) 1169 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode)); 1170 else 1171 ep->e2d_type = EXT2_FT_UNKNOWN; 1172 ext2_dirent_csum_set(dp, (struct ext2fs_direct_2 *)bp->b_data); 1173 error = bwrite(bp); 1174 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1175 return (error); 1176 } 1177 1178 /* 1179 * Check if a directory is empty or not. 1180 * Inode supplied must be locked. 1181 * 1182 * Using a struct dirtemplate here is not precisely 1183 * what we want, but better than using a struct direct. 1184 * 1185 * NB: does not handle corrupted directories. 1186 */ 1187 int 1188 ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred) 1189 { 1190 off_t off; 1191 struct dirtemplate dbuf; 1192 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf; 1193 int error, namlen; 1194 ssize_t count; 1195 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2) 1196 1197 for (off = 0; off < ip->i_size; off += le16toh(dp->e2d_reclen)) { 1198 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, 1199 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, 1200 NOCRED, &count, (struct thread *)0); 1201 /* 1202 * Since we read MINDIRSIZ, residual must 1203 * be 0 unless we're at end of file. 1204 */ 1205 if (error || count != 0) 1206 return (0); 1207 /* avoid infinite loops */ 1208 if (dp->e2d_reclen == 0) 1209 return (0); 1210 /* skip empty entries */ 1211 if (dp->e2d_ino == 0) 1212 continue; 1213 /* accept only "." and ".." */ 1214 namlen = dp->e2d_namlen; 1215 if (namlen > 2) 1216 return (0); 1217 if (dp->e2d_name[0] != '.') 1218 return (0); 1219 /* 1220 * At this point namlen must be 1 or 2. 1221 * 1 implies ".", 2 implies ".." if second 1222 * char is also "." 1223 */ 1224 if (namlen == 1) 1225 continue; 1226 if (dp->e2d_name[1] == '.' && le32toh(dp->e2d_ino) == parentino) 1227 continue; 1228 return (0); 1229 } 1230 return (1); 1231 } 1232 1233 /* 1234 * Check if source directory is in the path of the target directory. 1235 * Target is supplied locked, source is unlocked. 1236 * The target is always vput before returning. 1237 */ 1238 int 1239 ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred) 1240 { 1241 struct vnode *vp; 1242 int error, namlen; 1243 struct dirtemplate dirbuf; 1244 1245 vp = ITOV(target); 1246 if (target->i_number == source->i_number) { 1247 error = EEXIST; 1248 goto out; 1249 } 1250 if (target->i_number == EXT2_ROOTINO) { 1251 error = 0; 1252 goto out; 1253 } 1254 1255 for (;;) { 1256 if (vp->v_type != VDIR) { 1257 error = ENOTDIR; 1258 break; 1259 } 1260 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf, 1261 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, 1262 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, 1263 NULL); 1264 if (error != 0) 1265 break; 1266 namlen = dirbuf.dotdot_type; /* like ufs little-endian */ 1267 if (namlen != 2 || 1268 dirbuf.dotdot_name[0] != '.' || 1269 dirbuf.dotdot_name[1] != '.') { 1270 error = ENOTDIR; 1271 break; 1272 } 1273 if (le32toh(dirbuf.dotdot_ino) == source->i_number) { 1274 error = EINVAL; 1275 break; 1276 } 1277 if (le32toh(dirbuf.dotdot_ino) == EXT2_ROOTINO) 1278 break; 1279 vput(vp); 1280 if ((error = VFS_VGET(vp->v_mount, le32toh(dirbuf.dotdot_ino), 1281 LK_EXCLUSIVE, &vp)) != 0) { 1282 vp = NULL; 1283 break; 1284 } 1285 } 1286 1287 out: 1288 if (error == ENOTDIR) 1289 SDT_PROBE2(ext2fs, , lookup, trace, 1, 1290 "checkpath: .. not a directory"); 1291 if (vp != NULL) 1292 vput(vp); 1293 return (error); 1294 }
Cache object: 7b3e1cdab8a4994485a368a9c5165cf0
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