ext2_lookup.c revision 332750
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: stable/10/sys/fs/ext2fs/ext2_lookup.c 332750 2018-04-19 02:50:15Z pfg $ 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 66static int dirchk = 1; 67#else 68static int dirchk = 0; 69#endif 70 71static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem"); 72SYSCTL_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 81static 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 94static 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 114static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, 115 int entryoffsetinblock); 116static int ext2_is_dot_entry(struct componentname *cnp); 117static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, 118 struct componentname *cnp, ino_t *dd_ino); 119 120static int 121ext2_is_dot_entry(struct componentname *cnp) 122{ 123 if (cnp->cn_namelen <= 2 && cnp->cn_nameptr[0] == '.' && 124 (cnp->cn_nameptr[1] == '.' || cnp->cn_nameptr[1] == '\0')) 125 return (1); 126 return (0); 127} 128 129/* 130 * Vnode op for reading directories. 131 */ 132int 133ext2_readdir(struct vop_readdir_args *ap) 134{ 135 struct vnode *vp = ap->a_vp; 136 struct uio *uio = ap->a_uio; 137 struct buf *bp; 138 struct inode *ip; 139 struct ext2fs_direct_2 *dp, *edp; 140 u_long *cookies; 141 struct dirent dstdp; 142 off_t offset, startoffset; 143 size_t readcnt, skipcnt; 144 ssize_t startresid; 145 int ncookies; 146 int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize; 147 int error; 148 149 if (uio->uio_offset < 0) 150 return (EINVAL); 151 ip = VTOI(vp); 152 if (ap->a_ncookies != NULL) { 153 if (uio->uio_resid < 0) 154 ncookies = 0; 155 else 156 ncookies = uio->uio_resid; 157 if (uio->uio_offset >= ip->i_size) 158 ncookies = 0; 159 else if (ip->i_size - uio->uio_offset < ncookies) 160 ncookies = ip->i_size - uio->uio_offset; 161 ncookies = ncookies / (offsetof(struct ext2fs_direct_2, 162 e2d_namlen) + 4) + 1; 163 cookies = malloc(ncookies * sizeof(*cookies), M_TEMP, M_WAITOK); 164 *ap->a_ncookies = ncookies; 165 *ap->a_cookies = cookies; 166 } else { 167 ncookies = 0; 168 cookies = NULL; 169 } 170 offset = startoffset = uio->uio_offset; 171 startresid = uio->uio_resid; 172 error = 0; 173 while (error == 0 && uio->uio_resid > 0 && 174 uio->uio_offset < ip->i_size) { 175 error = ext2_blkatoff(vp, uio->uio_offset, NULL, &bp); 176 if (error) 177 break; 178 if (bp->b_offset + bp->b_bcount > ip->i_size) 179 readcnt = ip->i_size - bp->b_offset; 180 else 181 readcnt = bp->b_bcount; 182 skipcnt = (size_t)(uio->uio_offset - bp->b_offset) & 183 ~(size_t)(DIRBLKSIZ - 1); 184 offset = bp->b_offset + skipcnt; 185 dp = (struct ext2fs_direct_2 *)&bp->b_data[skipcnt]; 186 edp = (struct ext2fs_direct_2 *)&bp->b_data[readcnt]; 187 while (error == 0 && uio->uio_resid > 0 && dp < edp) { 188 if (dp->e2d_reclen <= offsetof(struct ext2fs_direct_2, 189 e2d_namlen) || (caddr_t)dp + dp->e2d_reclen > 190 (caddr_t)edp) { 191 error = EIO; 192 break; 193 } 194 /*- 195 * "New" ext2fs directory entries differ in 3 ways 196 * from ufs on-disk ones: 197 * - the name is not necessarily NUL-terminated. 198 * - the file type field always exists and always 199 * follows the name length field. 200 * - the file type is encoded in a different way. 201 * 202 * "Old" ext2fs directory entries need no special 203 * conversions, since they are binary compatible 204 * with "new" entries having a file type of 0 (i.e., 205 * EXT2_FT_UNKNOWN). Splitting the old name length 206 * field didn't make a mess like it did in ufs, 207 * because ext2fs uses a machine-independent disk 208 * layout. 209 */ 210 dstdp.d_namlen = dp->e2d_namlen; 211 dstdp.d_type = FTTODT(dp->e2d_type); 212 if (offsetof(struct ext2fs_direct_2, e2d_namlen) + 213 dstdp.d_namlen > dp->e2d_reclen) { 214 error = EIO; 215 break; 216 } 217 if (offset < startoffset || dp->e2d_ino == 0) 218 goto nextentry; 219 dstdp.d_fileno = dp->e2d_ino; 220 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp); 221 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen); 222 dstdp.d_name[dstdp.d_namlen] = '\0'; 223 if (dstdp.d_reclen > uio->uio_resid) { 224 if (uio->uio_resid == startresid) 225 error = EINVAL; 226 else 227 error = EJUSTRETURN; 228 break; 229 } 230 /* Advance dp. */ 231 error = uiomove((caddr_t)&dstdp, dstdp.d_reclen, uio); 232 if (error) 233 break; 234 if (cookies != NULL) { 235 KASSERT(ncookies > 0, 236 ("ext2_readdir: cookies buffer too small")); 237 *cookies = offset + dp->e2d_reclen; 238 cookies++; 239 ncookies--; 240 } 241nextentry: 242 offset += dp->e2d_reclen; 243 dp = (struct ext2fs_direct_2 *)((caddr_t)dp + 244 dp->e2d_reclen); 245 } 246 bqrelse(bp); 247 uio->uio_offset = offset; 248 } 249 /* We need to correct uio_offset. */ 250 uio->uio_offset = offset; 251 if (error == EJUSTRETURN) 252 error = 0; 253 if (ap->a_ncookies != NULL) { 254 if (error == 0) { 255 ap->a_ncookies -= ncookies; 256 } else { 257 free(*ap->a_cookies, M_TEMP); 258 *ap->a_ncookies = 0; 259 *ap->a_cookies = NULL; 260 } 261 } 262 if (error == 0 && ap->a_eofflag) 263 *ap->a_eofflag = ip->i_size <= uio->uio_offset; 264 return (error); 265} 266 267/* 268 * Convert a component of a pathname into a pointer to a locked inode. 269 * This is a very central and rather complicated routine. 270 * If the file system is not maintained in a strict tree hierarchy, 271 * this can result in a deadlock situation (see comments in code below). 272 * 273 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending 274 * on whether the name is to be looked up, created, renamed, or deleted. 275 * When CREATE, RENAME, or DELETE is specified, information usable in 276 * creating, renaming, or deleting a directory entry may be calculated. 277 * If flag has LOCKPARENT or'ed into it and the target of the pathname 278 * exists, lookup returns both the target and its parent directory locked. 279 * When creating or renaming and LOCKPARENT is specified, the target may 280 * not be ".". When deleting and LOCKPARENT is specified, the target may 281 * be "."., but the caller must check to ensure it does an vrele and vput 282 * instead of two vputs. 283 * 284 * Overall outline of ext2_lookup: 285 * 286 * search for name in directory, to found or notfound 287 * notfound: 288 * if creating, return locked directory, leaving info on available slots 289 * else return error 290 * found: 291 * if at end of path and deleting, return information to allow delete 292 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 293 * inode and return info to allow rewrite 294 * if not at end, add name to cache; if at end and neither creating 295 * nor deleting, add name to cache 296 */ 297int 298ext2_lookup(struct vop_cachedlookup_args *ap) 299{ 300 301 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); 302} 303 304static int 305ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, 306 ino_t *dd_ino) 307{ 308 struct inode *dp; /* inode for directory being searched */ 309 struct buf *bp; /* a buffer of directory entries */ 310 struct ext2fs_direct_2 *ep; /* the current directory entry */ 311 int entryoffsetinblock; /* offset of ep in bp's buffer */ 312 struct ext2fs_searchslot ss; 313 doff_t i_diroff; /* cached i_diroff value */ 314 doff_t i_offset; /* cached i_offset value */ 315 int numdirpasses; /* strategy for directory search */ 316 doff_t endsearch; /* offset to end directory search */ 317 doff_t prevoff; /* prev entry dp->i_offset */ 318 struct vnode *pdp; /* saved dp during symlink work */ 319 struct vnode *tdp; /* returned by VFS_VGET */ 320 doff_t enduseful; /* pointer past last used dir slot */ 321 u_long bmask; /* block offset mask */ 322 int error; 323 struct ucred *cred = cnp->cn_cred; 324 int flags = cnp->cn_flags; 325 int nameiop = cnp->cn_nameiop; 326 ino_t ino, ino1; 327 int ltype; 328 int entry_found = 0; 329 330 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize; 331 332 if (vpp != NULL) 333 *vpp = NULL; 334 335 dp = VTOI(vdp); 336 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 337restart: 338 bp = NULL; 339 ss.slotoffset = -1; 340 341 /* 342 * We now have a segment name to search for, and a directory to search. 343 * 344 * Suppress search for slots unless creating 345 * file and at end of pathname, in which case 346 * we watch for a place to put the new file in 347 * case it doesn't already exist. 348 */ 349 i_diroff = dp->i_diroff; 350 ss.slotstatus = FOUND; 351 ss.slotfreespace = ss.slotsize = ss.slotneeded = 0; 352 if ((nameiop == CREATE || nameiop == RENAME) && 353 (flags & ISLASTCN)) { 354 ss.slotstatus = NONE; 355 ss.slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen); 356 /* 357 * was ss.slotneeded = (sizeof(struct direct) - MAXNAMLEN + 358 * cnp->cn_namelen + 3) &~ 3; 359 */ 360 } 361 /* 362 * Try to lookup dir entry using htree directory index. 363 * 364 * If we got an error or we want to find '.' or '..' entry, 365 * we will fall back to linear search. 366 */ 367 if (!ext2_is_dot_entry(cnp) && ext2_htree_has_idx(dp)) { 368 numdirpasses = 1; 369 entryoffsetinblock = 0; 370 switch (ext2_htree_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen, 371 &bp, &entryoffsetinblock, &i_offset, &prevoff, 372 &enduseful, &ss)) { 373 case 0: 374 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data + 375 (i_offset & bmask)); 376 goto foundentry; 377 case ENOENT: 378 i_offset = roundup2(dp->i_size, DIRBLKSIZ); 379 goto notfound; 380 default: 381 /* 382 * Something failed; just fallback to do a linear 383 * search. 384 */ 385 break; 386 } 387 } 388 389 /* 390 * If there is cached information on a previous search of 391 * this directory, pick up where we last left off. 392 * We cache only lookups as these are the most common 393 * and have the greatest payoff. Caching CREATE has little 394 * benefit as it usually must search the entire directory 395 * to determine that the entry does not exist. Caching the 396 * location of the last DELETE or RENAME has not reduced 397 * profiling time and hence has been removed in the interest 398 * of simplicity. 399 */ 400 if (nameiop != LOOKUP || i_diroff == 0 || 401 i_diroff > dp->i_size) { 402 entryoffsetinblock = 0; 403 i_offset = 0; 404 numdirpasses = 1; 405 } else { 406 i_offset = i_diroff; 407 if ((entryoffsetinblock = i_offset & bmask) && 408 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, 409 &bp))) 410 return (error); 411 numdirpasses = 2; 412 nchstats.ncs_2passes++; 413 } 414 prevoff = i_offset; 415 endsearch = roundup2(dp->i_size, DIRBLKSIZ); 416 enduseful = 0; 417 418searchloop: 419 while (i_offset < endsearch) { 420 /* 421 * If necessary, get the next directory block. 422 */ 423 if (bp != NULL) 424 brelse(bp); 425 error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, &bp); 426 if (error != 0) 427 return (error); 428 entryoffsetinblock = 0; 429 /* 430 * If still looking for a slot, and at a DIRBLKSIZE 431 * boundary, have to start looking for free space again. 432 */ 433 if (ss.slotstatus == NONE && 434 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) { 435 ss.slotoffset = -1; 436 ss.slotfreespace = 0; 437 } 438 error = ext2_search_dirblock(dp, bp->b_data, &entry_found, 439 cnp->cn_nameptr, cnp->cn_namelen, 440 &entryoffsetinblock, &i_offset, &prevoff, 441 &enduseful, &ss); 442 if (error != 0) { 443 brelse(bp); 444 return (error); 445 } 446 if (entry_found) { 447 ep = (struct ext2fs_direct_2 *)((char *)bp->b_data + 448 (entryoffsetinblock & bmask)); 449foundentry: 450 ino = ep->e2d_ino; 451 goto found; 452 } 453 } 454notfound: 455 /* 456 * If we started in the middle of the directory and failed 457 * to find our target, we must check the beginning as well. 458 */ 459 if (numdirpasses == 2) { 460 numdirpasses--; 461 i_offset = 0; 462 endsearch = i_diroff; 463 goto searchloop; 464 } 465 if (bp != NULL) 466 brelse(bp); 467 /* 468 * If creating, and at end of pathname and current 469 * directory has not been removed, then can consider 470 * allowing file to be created. 471 */ 472 if ((nameiop == CREATE || nameiop == RENAME) && 473 (flags & ISLASTCN) && dp->i_nlink != 0) { 474 /* 475 * Access for write is interpreted as allowing 476 * creation of files in the directory. 477 */ 478 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 479 return (error); 480 /* 481 * Return an indication of where the new directory 482 * entry should be put. If we didn't find a slot, 483 * then set dp->i_count to 0 indicating 484 * that the new slot belongs at the end of the 485 * directory. If we found a slot, then the new entry 486 * can be put in the range from dp->i_offset to 487 * dp->i_offset + dp->i_count. 488 */ 489 if (ss.slotstatus == NONE) { 490 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ); 491 dp->i_count = 0; 492 enduseful = dp->i_offset; 493 } else { 494 dp->i_offset = ss.slotoffset; 495 dp->i_count = ss.slotsize; 496 if (enduseful < ss.slotoffset + ss.slotsize) 497 enduseful = ss.slotoffset + ss.slotsize; 498 } 499 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ); 500 /* 501 * We return with the directory locked, so that 502 * the parameters we set up above will still be 503 * valid if we actually decide to do a direnter(). 504 * We return ni_vp == NULL to indicate that the entry 505 * does not currently exist; we leave a pointer to 506 * the (locked) directory inode in ndp->ni_dvp. 507 * The pathname buffer is saved so that the name 508 * can be obtained later. 509 * 510 * NB - if the directory is unlocked, then this 511 * information cannot be used. 512 */ 513 cnp->cn_flags |= SAVENAME; 514 return (EJUSTRETURN); 515 } 516 /* 517 * Insert name into cache (as non-existent) if appropriate. 518 */ 519 if ((cnp->cn_flags & MAKEENTRY) != 0) 520 cache_enter(vdp, NULL, cnp); 521 return (ENOENT); 522 523found: 524 if (dd_ino != NULL) 525 *dd_ino = ino; 526 if (numdirpasses == 2) 527 nchstats.ncs_pass2++; 528 /* 529 * Check that directory length properly reflects presence 530 * of this entry. 531 */ 532 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) 533 > dp->i_size) { 534 ext2_dirbad(dp, i_offset, "i_size too small"); 535 dp->i_size = entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen); 536 dp->i_flag |= IN_CHANGE | IN_UPDATE; 537 } 538 brelse(bp); 539 540 /* 541 * Found component in pathname. 542 * If the final component of path name, save information 543 * in the cache as to where the entry was found. 544 */ 545 if ((flags & ISLASTCN) && nameiop == LOOKUP) 546 dp->i_diroff = i_offset &~ (DIRBLKSIZ - 1); 547 /* 548 * If deleting, and at end of pathname, return 549 * parameters which can be used to remove file. 550 */ 551 if (nameiop == DELETE && (flags & ISLASTCN)) { 552 if (flags & LOCKPARENT) 553 ASSERT_VOP_ELOCKED(vdp, __FUNCTION__); 554 /* 555 * Write access to directory required to delete files. 556 */ 557 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 558 return (error); 559 /* 560 * Return pointer to current entry in dp->i_offset, 561 * and distance past previous entry (if there 562 * is a previous entry in this block) in dp->i_count. 563 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 564 * 565 * Technically we shouldn't be setting these in the 566 * WANTPARENT case (first lookup in rename()), but any 567 * lookups that will result in directory changes will 568 * overwrite these. 569 */ 570 dp->i_offset = i_offset; 571 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) 572 dp->i_count = 0; 573 else 574 dp->i_count = dp->i_offset - prevoff; 575 if (dd_ino != NULL) 576 return (0); 577 if (dp->i_number == ino) { 578 VREF(vdp); 579 *vpp = vdp; 580 return (0); 581 } 582 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 583 &tdp)) != 0) 584 return (error); 585 /* 586 * If directory is "sticky", then user must own 587 * the directory, or the file in it, else she 588 * may not delete it (unless she's root). This 589 * implements append-only directories. 590 */ 591 if ((dp->i_mode & ISVTX) && 592 cred->cr_uid != 0 && 593 cred->cr_uid != dp->i_uid && 594 VTOI(tdp)->i_uid != cred->cr_uid) { 595 vput(tdp); 596 return (EPERM); 597 } 598 *vpp = tdp; 599 return (0); 600 } 601 602 /* 603 * If rewriting (RENAME), return the inode and the 604 * information required to rewrite the present directory 605 * Must get inode of directory entry to verify it's a 606 * regular file, or empty directory. 607 */ 608 if (nameiop == RENAME && (flags & ISLASTCN)) { 609 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 610 return (error); 611 /* 612 * Careful about locking second inode. 613 * This can only occur if the target is ".". 614 */ 615 dp->i_offset = i_offset; 616 if (dp->i_number == ino) 617 return (EISDIR); 618 if (dd_ino != NULL) 619 return (0); 620 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 621 &tdp)) != 0) 622 return (error); 623 *vpp = tdp; 624 cnp->cn_flags |= SAVENAME; 625 return (0); 626 } 627 if (dd_ino != NULL) 628 return (0); 629 630 /* 631 * Step through the translation in the name. We do not `vput' the 632 * directory because we may need it again if a symbolic link 633 * is relative to the current directory. Instead we save it 634 * unlocked as "pdp". We must get the target inode before unlocking 635 * the directory to insure that the inode will not be removed 636 * before we get it. We prevent deadlock by always fetching 637 * inodes from the root, moving down the directory tree. Thus 638 * when following backward pointers ".." we must unlock the 639 * parent directory before getting the requested directory. 640 * There is a potential race condition here if both the current 641 * and parent directories are removed before the VFS_VGET for the 642 * inode associated with ".." returns. We hope that this occurs 643 * infrequently since we cannot avoid this race condition without 644 * implementing a sophisticated deadlock detection algorithm. 645 * Note also that this simple deadlock detection scheme will not 646 * work if the file system has any hard links other than ".." 647 * that point backwards in the directory structure. 648 */ 649 pdp = vdp; 650 if (flags & ISDOTDOT) { 651 error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp); 652 if (pdp->v_iflag & VI_DOOMED) { 653 if (error == 0) 654 vput(tdp); 655 error = ENOENT; 656 } 657 if (error) 658 return (error); 659 /* 660 * Recheck that ".." entry in the vdp directory points 661 * to the inode we looked up before vdp lock was 662 * dropped. 663 */ 664 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1); 665 if (error) { 666 vput(tdp); 667 return (error); 668 } 669 if (ino1 != ino) { 670 vput(tdp); 671 goto restart; 672 } 673 *vpp = tdp; 674 } else if (dp->i_number == ino) { 675 VREF(vdp); /* we want ourself, ie "." */ 676 /* 677 * When we lookup "." we still can be asked to lock it 678 * differently. 679 */ 680 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 681 if (ltype != VOP_ISLOCKED(vdp)) { 682 if (ltype == LK_EXCLUSIVE) 683 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 684 else /* if (ltype == LK_SHARED) */ 685 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 686 } 687 *vpp = vdp; 688 } else { 689 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags, 690 &tdp)) != 0) 691 return (error); 692 *vpp = tdp; 693 } 694 695 /* 696 * Insert name into cache if appropriate. 697 */ 698 if (cnp->cn_flags & MAKEENTRY) 699 cache_enter(vdp, *vpp, cnp); 700 return (0); 701} 702 703int 704ext2_search_dirblock(struct inode *ip, void *data, int *foundp, 705 const char *name, int namelen, int *entryoffsetinblockp, 706 doff_t *offp, doff_t *prevoffp, doff_t *endusefulp, 707 struct ext2fs_searchslot *ssp) 708{ 709 struct vnode *vdp; 710 struct ext2fs_direct_2 *ep, *top; 711 uint32_t bsize = ip->i_e2fs->e2fs_bsize; 712 int offset = *entryoffsetinblockp; 713 int namlen; 714 715 vdp = ITOV(ip); 716 717 ep = (struct ext2fs_direct_2 *)((char *)data + offset); 718 top = (struct ext2fs_direct_2 *)((char *)data + 719 bsize - EXT2_DIR_REC_LEN(0)); 720 721 while (ep < top) { 722 /* 723 * Full validation checks are slow, so we only check 724 * enough to insure forward progress through the 725 * directory. Complete checks can be run by setting 726 * "vfs.e2fs.dirchk" to be true. 727 */ 728 if (ep->e2d_reclen == 0 || 729 (dirchk && ext2_dirbadentry(vdp, ep, offset))) { 730 int i; 731 732 ext2_dirbad(ip, *offp, "mangled entry"); 733 i = bsize - (offset & (bsize - 1)); 734 *offp += i; 735 offset += i; 736 continue; 737 } 738 739 /* 740 * If an appropriate sized slot has not yet been found, 741 * check to see if one is available. Also accumulate space 742 * in the current block so that we can determine if 743 * compaction is viable. 744 */ 745 if (ssp->slotstatus != FOUND) { 746 int size = ep->e2d_reclen; 747 748 if (ep->e2d_ino != 0) 749 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen); 750 if (size > 0) { 751 if (size >= ssp->slotneeded) { 752 ssp->slotstatus = FOUND; 753 ssp->slotoffset = *offp; 754 ssp->slotsize = ep->e2d_reclen; 755 } else if (ssp->slotstatus == NONE) { 756 ssp->slotfreespace += size; 757 if (ssp->slotoffset == -1) 758 ssp->slotoffset = *offp; 759 if (ssp->slotfreespace >= ssp->slotneeded) { 760 ssp->slotstatus = COMPACT; 761 ssp->slotsize = *offp + 762 ep->e2d_reclen - 763 ssp->slotoffset; 764 } 765 } 766 } 767 } 768 /* 769 * Check for a name match. 770 */ 771 if (ep->e2d_ino) { 772 namlen = ep->e2d_namlen; 773 if (namlen == namelen && 774 !bcmp(name, ep->e2d_name, (unsigned)namlen)) { 775 /* 776 * Save directory entry's inode number and 777 * reclen in ndp->ni_ufs area, and release 778 * directory buffer. 779 */ 780 *foundp = 1; 781 return (0); 782 } 783 } 784 *prevoffp = *offp; 785 *offp += ep->e2d_reclen; 786 offset += ep->e2d_reclen; 787 *entryoffsetinblockp = offset; 788 if (ep->e2d_ino) 789 *endusefulp = *offp; 790 /* 791 * Get pointer to the next entry. 792 */ 793 ep = (struct ext2fs_direct_2 *)((char *)data + offset); 794 } 795 796 return (0); 797} 798 799void 800ext2_dirbad(struct inode *ip, doff_t offset, char *how) 801{ 802 struct mount *mp; 803 804 mp = ITOV(ip)->v_mount; 805 if ((mp->mnt_flag & MNT_RDONLY) == 0) 806 panic("ext2_dirbad: %s: bad dir ino %lu at offset %ld: %s\n", 807 mp->mnt_stat.f_mntonname, (u_long)ip->i_number,(long)offset, how); 808 else 809 (void)printf("%s: bad dir ino %lu at offset %ld: %s\n", 810 mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how); 811 812} 813 814/* 815 * Do consistency checking on a directory entry: 816 * record length must be multiple of 4 817 * entry must fit in rest of its DIRBLKSIZ block 818 * record must be large enough to contain entry 819 * name is not longer than MAXNAMLEN 820 * name must be as long as advertised, and null terminated 821 */ 822/* 823 * changed so that it confirms to ext2_check_dir_entry 824 */ 825static int 826ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, 827 int entryoffsetinblock) 828{ 829 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize; 830 831 char *error_msg = NULL; 832 833 if (de->e2d_reclen < EXT2_DIR_REC_LEN(1)) 834 error_msg = "rec_len is smaller than minimal"; 835 else if (de->e2d_reclen % 4 != 0) 836 error_msg = "rec_len % 4 != 0"; 837 else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen)) 838 error_msg = "reclen is too small for name_len"; 839 else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ) 840 error_msg = "directory entry across blocks"; 841 /* else LATER 842 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count) 843 error_msg = "inode out of bounds"; 844 */ 845 846 if (error_msg != NULL) { 847 printf("bad directory entry: %s\n", error_msg); 848 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n", 849 entryoffsetinblock, (unsigned long)de->e2d_ino, 850 de->e2d_reclen, de->e2d_namlen); 851 } 852 return error_msg == NULL ? 0 : 1; 853} 854 855/* 856 * Write a directory entry after a call to namei, using the parameters 857 * that it left in nameidata. The argument ip is the inode which the new 858 * directory entry will refer to. Dvp is a pointer to the directory to 859 * be written, which was left locked by namei. Remaining parameters 860 * (dp->i_offset, dp->i_count) indicate how the space for the new 861 * entry is to be obtained. 862 */ 863int 864ext2_direnter(struct inode *ip, struct vnode *dvp, struct componentname *cnp) 865{ 866 struct inode *dp; 867 struct ext2fs_direct_2 newdir; 868 struct iovec aiov; 869 struct uio auio; 870 int error, newentrysize; 871 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize; 872 873 874#ifdef INVARIANTS 875 if ((cnp->cn_flags & SAVENAME) == 0) 876 panic("ext2_direnter: missing name"); 877#endif 878 dp = VTOI(dvp); 879 newdir.e2d_ino = ip->i_number; 880 newdir.e2d_namlen = cnp->cn_namelen; 881 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 882 EXT2F_INCOMPAT_FTYPE)) 883 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode)); 884 else 885 newdir.e2d_type = EXT2_FT_UNKNOWN; 886 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1); 887 newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen); 888 889 if (ext2_htree_has_idx(dp)) { 890 error = ext2_htree_add_entry(dvp, &newdir, cnp); 891 if (error) { 892 dp->i_flag &= ~IN_E3INDEX; 893 dp->i_flag |= IN_CHANGE | IN_UPDATE; 894 } 895 return (error); 896 } 897 898 if (EXT2_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_DIRHASHINDEX) && 899 !ext2_htree_has_idx(dp)) { 900 if ((dp->i_size / DIRBLKSIZ) == 1 && 901 dp->i_offset == DIRBLKSIZ) { 902 /* 903 * Making indexed directory when one block is not 904 * enough to save all entries. 905 */ 906 return ext2_htree_create_index(dvp, cnp, &newdir); 907 } 908 } 909 910 if (dp->i_count == 0) { 911 /* 912 * If dp->i_count is 0, then namei could find no 913 * space in the directory. Here, dp->i_offset will 914 * be on a directory block boundary and we will write the 915 * new entry into a fresh block. 916 */ 917 if (dp->i_offset & (DIRBLKSIZ - 1)) 918 panic("ext2_direnter: newblk"); 919 auio.uio_offset = dp->i_offset; 920 newdir.e2d_reclen = DIRBLKSIZ; 921 auio.uio_resid = newentrysize; 922 aiov.iov_len = newentrysize; 923 aiov.iov_base = (caddr_t)&newdir; 924 auio.uio_iov = &aiov; 925 auio.uio_iovcnt = 1; 926 auio.uio_rw = UIO_WRITE; 927 auio.uio_segflg = UIO_SYSSPACE; 928 auio.uio_td = (struct thread *)0; 929 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred); 930 if (DIRBLKSIZ > 931 VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize) 932 /* XXX should grow with balloc() */ 933 panic("ext2_direnter: frag size"); 934 else if (!error) { 935 dp->i_size = roundup2(dp->i_size, DIRBLKSIZ); 936 dp->i_flag |= IN_CHANGE; 937 } 938 return (error); 939 } 940 941 error = ext2_add_entry(dvp, &newdir); 942 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size) 943 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC, 944 cnp->cn_cred, cnp->cn_thread); 945 return (error); 946} 947 948/* 949 * Insert an entry into the directory block. 950 * Compact the contents. 951 */ 952int 953ext2_add_entry(struct vnode *dvp, struct ext2fs_direct_2 *entry) 954{ 955 struct ext2fs_direct_2 *ep, *nep; 956 struct inode *dp; 957 struct buf *bp; 958 u_int dsize; 959 int error, loc, newentrysize, spacefree; 960 char *dirbuf; 961 962 dp = VTOI(dvp); 963 964 /* 965 * If dp->i_count is non-zero, then namei found space 966 * for the new entry in the range dp->i_offset to 967 * dp->i_offset + dp->i_count in the directory. 968 * To use this space, we may have to compact the entries located 969 * there, by copying them together towards the beginning of the 970 * block, leaving the free space in one usable chunk at the end. 971 */ 972 973 /* 974 * Increase size of directory if entry eats into new space. 975 * This should never push the size past a new multiple of 976 * DIRBLKSIZE. 977 * 978 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. 979 */ 980 if (dp->i_offset + dp->i_count > dp->i_size) 981 dp->i_size = dp->i_offset + dp->i_count; 982 /* 983 * Get the block containing the space for the new directory entry. 984 */ 985 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf, 986 &bp)) != 0) 987 return (error); 988 /* 989 * Find space for the new entry. In the simple case, the entry at 990 * offset base will have the space. If it does not, then namei 991 * arranged that compacting the region dp->i_offset to 992 * dp->i_offset + dp->i_count would yield the 993 * space. 994 */ 995 newentrysize = EXT2_DIR_REC_LEN(entry->e2d_namlen); 996 ep = (struct ext2fs_direct_2 *)dirbuf; 997 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen); 998 spacefree = ep->e2d_reclen - dsize; 999 for (loc = ep->e2d_reclen; loc < dp->i_count; ) { 1000 nep = (struct ext2fs_direct_2 *)(dirbuf + loc); 1001 if (ep->e2d_ino) { 1002 /* trim the existing slot */ 1003 ep->e2d_reclen = dsize; 1004 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 1005 } else { 1006 /* overwrite; nothing there; header is ours */ 1007 spacefree += dsize; 1008 } 1009 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen); 1010 spacefree += nep->e2d_reclen - dsize; 1011 loc += nep->e2d_reclen; 1012 bcopy((caddr_t)nep, (caddr_t)ep, dsize); 1013 } 1014 /* 1015 * Update the pointer fields in the previous entry (if any), 1016 * copy in the new entry, and write out the block. 1017 */ 1018 if (ep->e2d_ino == 0) { 1019 if (spacefree + dsize < newentrysize) 1020 panic("ext2_direnter: compact1"); 1021 entry->e2d_reclen = spacefree + dsize; 1022 } else { 1023 if (spacefree < newentrysize) 1024 panic("ext2_direnter: compact2"); 1025 entry->e2d_reclen = spacefree; 1026 ep->e2d_reclen = dsize; 1027 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 1028 } 1029 bcopy((caddr_t)entry, (caddr_t)ep, (u_int)newentrysize); 1030 if (DOINGASYNC(dvp)) { 1031 bdwrite(bp); 1032 error = 0; 1033 } else { 1034 error = bwrite(bp); 1035 } 1036 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1037 return (error); 1038} 1039 1040/* 1041 * Remove a directory entry after a call to namei, using 1042 * the parameters which it left in nameidata. The entry 1043 * dp->i_offset contains the offset into the directory of the 1044 * entry to be eliminated. The dp->i_count field contains the 1045 * size of the previous record in the directory. If this 1046 * is 0, the first entry is being deleted, so we need only 1047 * zero the inode number to mark the entry as free. If the 1048 * entry is not the first in the directory, we must reclaim 1049 * the space of the now empty record by adding the record size 1050 * to the size of the previous entry. 1051 */ 1052int 1053ext2_dirremove(struct vnode *dvp, struct componentname *cnp) 1054{ 1055 struct inode *dp; 1056 struct ext2fs_direct_2 *ep, *rep; 1057 struct buf *bp; 1058 int error; 1059 1060 dp = VTOI(dvp); 1061 if (dp->i_count == 0) { 1062 /* 1063 * First entry in block: set d_ino to zero. 1064 */ 1065 if ((error = 1066 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep, 1067 &bp)) != 0) 1068 return (error); 1069 ep->e2d_ino = 0; 1070 error = bwrite(bp); 1071 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1072 return (error); 1073 } 1074 /* 1075 * Collapse new free space into previous entry. 1076 */ 1077 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count), 1078 (char **)&ep, &bp)) != 0) 1079 return (error); 1080 1081 /* Set 'rep' to the entry being removed. */ 1082 if (dp->i_count == 0) 1083 rep = ep; 1084 else 1085 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen); 1086 ep->e2d_reclen += rep->e2d_reclen; 1087 if (DOINGASYNC(dvp) && dp->i_count != 0) 1088 bdwrite(bp); 1089 else 1090 error = bwrite(bp); 1091 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1092 return (error); 1093} 1094 1095/* 1096 * Rewrite an existing directory entry to point at the inode 1097 * supplied. The parameters describing the directory entry are 1098 * set up by a call to namei. 1099 */ 1100int 1101ext2_dirrewrite(struct inode *dp, struct inode *ip, struct componentname *cnp) 1102{ 1103 struct buf *bp; 1104 struct ext2fs_direct_2 *ep; 1105 struct vnode *vdp = ITOV(dp); 1106 int error; 1107 1108 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep, 1109 &bp)) != 0) 1110 return (error); 1111 ep->e2d_ino = ip->i_number; 1112 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 1113 EXT2F_INCOMPAT_FTYPE)) 1114 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode)); 1115 else 1116 ep->e2d_type = EXT2_FT_UNKNOWN; 1117 error = bwrite(bp); 1118 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1119 return (error); 1120} 1121 1122/* 1123 * Check if a directory is empty or not. 1124 * Inode supplied must be locked. 1125 * 1126 * Using a struct dirtemplate here is not precisely 1127 * what we want, but better than using a struct direct. 1128 * 1129 * NB: does not handle corrupted directories. 1130 */ 1131int 1132ext2_dirempty(struct inode *ip, ino_t parentino, struct ucred *cred) 1133{ 1134 off_t off; 1135 struct dirtemplate dbuf; 1136 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf; 1137 int error, namlen; 1138 ssize_t count; 1139#define MINDIRSIZ (sizeof(struct dirtemplate) / 2) 1140 1141 for (off = 0; off < ip->i_size; off += dp->e2d_reclen) { 1142 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, 1143 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, 1144 NOCRED, &count, (struct thread *)0); 1145 /* 1146 * Since we read MINDIRSIZ, residual must 1147 * be 0 unless we're at end of file. 1148 */ 1149 if (error || count != 0) 1150 return (0); 1151 /* avoid infinite loops */ 1152 if (dp->e2d_reclen == 0) 1153 return (0); 1154 /* skip empty entries */ 1155 if (dp->e2d_ino == 0) 1156 continue; 1157 /* accept only "." and ".." */ 1158 namlen = dp->e2d_namlen; 1159 if (namlen > 2) 1160 return (0); 1161 if (dp->e2d_name[0] != '.') 1162 return (0); 1163 /* 1164 * At this point namlen must be 1 or 2. 1165 * 1 implies ".", 2 implies ".." if second 1166 * char is also "." 1167 */ 1168 if (namlen == 1) 1169 continue; 1170 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino) 1171 continue; 1172 return (0); 1173 } 1174 return (1); 1175} 1176 1177/* 1178 * Check if source directory is in the path of the target directory. 1179 * Target is supplied locked, source is unlocked. 1180 * The target is always vput before returning. 1181 */ 1182int 1183ext2_checkpath(struct inode *source, struct inode *target, struct ucred *cred) 1184{ 1185 struct vnode *vp; 1186 int error, namlen; 1187 struct dirtemplate dirbuf; 1188 1189 vp = ITOV(target); 1190 if (target->i_number == source->i_number) { 1191 error = EEXIST; 1192 goto out; 1193 } 1194 if (target->i_number == EXT2_ROOTINO) { 1195 error = 0; 1196 goto out; 1197 } 1198 1199 for (;;) { 1200 if (vp->v_type != VDIR) { 1201 error = ENOTDIR; 1202 break; 1203 } 1204 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf, 1205 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, 1206 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, 1207 NULL); 1208 if (error != 0) 1209 break; 1210 namlen = dirbuf.dotdot_type; /* like ufs little-endian */ 1211 if (namlen != 2 || 1212 dirbuf.dotdot_name[0] != '.' || 1213 dirbuf.dotdot_name[1] != '.') { 1214 error = ENOTDIR; 1215 break; 1216 } 1217 if (dirbuf.dotdot_ino == source->i_number) { 1218 error = EINVAL; 1219 break; 1220 } 1221 if (dirbuf.dotdot_ino == EXT2_ROOTINO) 1222 break; 1223 vput(vp); 1224 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, 1225 LK_EXCLUSIVE, &vp)) != 0) { 1226 vp = NULL; 1227 break; 1228 } 1229 } 1230 1231out: 1232 if (error == ENOTDIR) 1233 printf("checkpath: .. not a directory\n"); 1234 if (vp != NULL) 1235 vput(vp); 1236 return (error); 1237} 1238