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