1 /* $NetBSD: ext2fs_lookup.c,v 1.74 2014/02/07 15:29:23 hannken Exp $ */ 2 3 /* 4 * Modified for NetBSD 1.2E 5 * May 1997, Manuel Bouyer 6 * Laboratoire d'informatique de Paris VI 7 */ 8 /* 9 * modified for Lites 1.1 10 * 11 * Aug 1995, Godmar Back (gback@cs.utah.edu) 12 * University of Utah, Department of Computer Science 13 */ 14 /* 15 * Copyright (c) 1989, 1993 16 * The Regents of the University of California. All rights reserved. 17 * (c) UNIX System Laboratories, Inc. 18 * All or some portions of this file are derived from material licensed 19 * to the University of California by American Telephone and Telegraph 20 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 21 * the permission of UNIX System Laboratories, Inc. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. Neither the name of the University nor the names of its contributors 32 * may be used to endorse or promote products derived from this software 33 * without specific prior written permission. 34 * 35 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 36 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 38 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 39 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 40 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 41 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 42 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 43 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 44 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 45 * SUCH DAMAGE. 46 * 47 * @(#)ufs_lookup.c 8.6 (Berkeley) 4/1/94 48 */ 49 50 #include <sys/cdefs.h> 51 __KERNEL_RCSID(0, "$NetBSD: ext2fs_lookup.c,v 1.74 2014/02/07 15:29:23 hannken Exp $"); 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/namei.h> 56 #include <sys/buf.h> 57 #include <sys/file.h> 58 #include <sys/mount.h> 59 #include <sys/vnode.h> 60 #include <sys/kmem.h> 61 #include <sys/malloc.h> 62 #include <sys/dirent.h> 63 #include <sys/kauth.h> 64 #include <sys/proc.h> 65 66 #include <ufs/ufs/inode.h> 67 #include <ufs/ufs/ufsmount.h> 68 #include <ufs/ufs/ufs_extern.h> 69 70 #include <ufs/ext2fs/ext2fs_extern.h> 71 #include <ufs/ext2fs/ext2fs_dir.h> 72 #include <ufs/ext2fs/ext2fs.h> 73 74 #include <miscfs/genfs/genfs.h> 75 76 extern int dirchk; 77 78 static void ext2fs_dirconv2ffs(struct ext2fs_direct *e2dir, 79 struct dirent *ffsdir); 80 static int ext2fs_dirbadentry(struct vnode *dp, 81 struct ext2fs_direct *de, 82 int entryoffsetinblock); 83 84 /* 85 * the problem that is tackled below is the fact that FFS 86 * includes the terminating zero on disk while EXT2FS doesn't 87 * this implies that we need to introduce some padding. 88 * For instance, a filename "sbin" has normally a reclen 12 89 * in EXT2, but 16 in FFS. 90 * This reminds me of that Pepsi commercial: 'Kid saved a lousy nine cents...' 91 * If it wasn't for that, the complete ufs code for directories would 92 * have worked w/o changes (except for the difference in DIRBLKSIZ) 93 */ 94 static void 95 ext2fs_dirconv2ffs(struct ext2fs_direct *e2dir, struct dirent *ffsdir) 96 { 97 memset(ffsdir, 0, sizeof(struct dirent)); 98 ffsdir->d_fileno = fs2h32(e2dir->e2d_ino); 99 ffsdir->d_namlen = e2dir->e2d_namlen; 100 101 ffsdir->d_type = DT_UNKNOWN; /* don't know more here */ 102 #ifdef DIAGNOSTIC 103 #if MAXNAMLEN < E2FS_MAXNAMLEN 104 /* 105 * we should handle this more gracefully ! 106 */ 107 if (e2dir->e2d_namlen > MAXNAMLEN) 108 panic("ext2fs: e2dir->e2d_namlen"); 109 #endif 110 #endif 111 strncpy(ffsdir->d_name, e2dir->e2d_name, ffsdir->d_namlen); 112 113 /* Godmar thinks: since e2dir->e2d_reclen can be big and means 114 nothing anyway, we compute our own reclen according to what 115 we think is right 116 */ 117 ffsdir->d_reclen = _DIRENT_SIZE(ffsdir); 118 } 119 120 /* 121 * Vnode op for reading directories. 122 * 123 * Convert the on-disk entries to <sys/dirent.h> entries. 124 * the problem is that the conversion will blow up some entries by four bytes, 125 * so it can't be done in place. This is too bad. Right now the conversion is 126 * done entry by entry, the converted entry is sent via uiomove. 127 * 128 * XXX allocate a buffer, convert as many entries as possible, then send 129 * the whole buffer to uiomove 130 */ 131 int 132 ext2fs_readdir(void *v) 133 { 134 struct vop_readdir_args /* { 135 struct vnode *a_vp; 136 struct uio *a_uio; 137 kauth_cred_t a_cred; 138 int **a_eofflag; 139 off_t **a_cookies; 140 int ncookies; 141 } */ *ap = v; 142 struct uio *uio = ap->a_uio; 143 int error; 144 size_t e2fs_count, readcnt; 145 struct vnode *vp = ap->a_vp; 146 struct m_ext2fs *fs = VTOI(vp)->i_e2fs; 147 148 struct ext2fs_direct *dp; 149 struct dirent *dstd; 150 struct uio auio; 151 struct iovec aiov; 152 void *dirbuf; 153 off_t off = uio->uio_offset; 154 off_t *cookies = NULL; 155 int nc = 0, ncookies = 0; 156 int e2d_reclen; 157 158 if (vp->v_type != VDIR) 159 return (ENOTDIR); 160 161 e2fs_count = uio->uio_resid; 162 /* Make sure we don't return partial entries. */ 163 e2fs_count -= (uio->uio_offset + e2fs_count) & (fs->e2fs_bsize -1); 164 if (e2fs_count <= 0) 165 return (EINVAL); 166 167 auio = *uio; 168 auio.uio_iov = &aiov; 169 auio.uio_iovcnt = 1; 170 aiov.iov_len = e2fs_count; 171 auio.uio_resid = e2fs_count; 172 UIO_SETUP_SYSSPACE(&auio); 173 dirbuf = kmem_alloc(e2fs_count, KM_SLEEP); 174 dstd = kmem_zalloc(sizeof(struct dirent), KM_SLEEP); 175 if (ap->a_ncookies) { 176 nc = e2fs_count / _DIRENT_MINSIZE((struct dirent *)0); 177 ncookies = nc; 178 cookies = malloc(sizeof (off_t) * ncookies, M_TEMP, M_WAITOK); 179 *ap->a_cookies = cookies; 180 } 181 aiov.iov_base = dirbuf; 182 183 error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred); 184 if (error == 0) { 185 readcnt = e2fs_count - auio.uio_resid; 186 for (dp = (struct ext2fs_direct *)dirbuf; 187 (char *)dp < (char *)dirbuf + readcnt; ) { 188 e2d_reclen = fs2h16(dp->e2d_reclen); 189 if (e2d_reclen == 0) { 190 error = EIO; 191 break; 192 } 193 ext2fs_dirconv2ffs(dp, dstd); 194 if(dstd->d_reclen > uio->uio_resid) { 195 break; 196 } 197 error = uiomove(dstd, dstd->d_reclen, uio); 198 if (error != 0) { 199 break; 200 } 201 off = off + e2d_reclen; 202 if (cookies != NULL) { 203 *cookies++ = off; 204 if (--ncookies <= 0){ 205 break; /* out of cookies */ 206 } 207 } 208 /* advance dp */ 209 dp = (struct ext2fs_direct *) ((char *)dp + e2d_reclen); 210 } 211 /* we need to correct uio_offset */ 212 uio->uio_offset = off; 213 } 214 kmem_free(dirbuf, e2fs_count); 215 kmem_free(dstd, sizeof(*dstd)); 216 *ap->a_eofflag = ext2fs_size(VTOI(ap->a_vp)) <= uio->uio_offset; 217 if (ap->a_ncookies) { 218 if (error) { 219 free(*ap->a_cookies, M_TEMP); 220 *ap->a_ncookies = 0; 221 *ap->a_cookies = NULL; 222 } else 223 *ap->a_ncookies = nc - ncookies; 224 } 225 return (error); 226 } 227 228 /* 229 * Convert a component of a pathname into a pointer to a locked inode. 230 * This is a very central and rather complicated routine. 231 * If the file system is not maintained in a strict tree hierarchy, 232 * this can result in a deadlock situation (see comments in code below). 233 * 234 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending 235 * on whether the name is to be looked up, created, renamed, or deleted. 236 * When CREATE, RENAME, or DELETE is specified, information usable in 237 * creating, renaming, or deleting a directory entry may be calculated. 238 * If flag has LOCKPARENT or'ed into it and the target of the pathname 239 * exists, lookup returns both the target and its parent directory locked. 240 * When creating or renaming and LOCKPARENT is specified, the target may 241 * not be ".". When deleting and LOCKPARENT is specified, the target may 242 * be "."., but the caller must check to ensure it does an vrele and vput 243 * instead of two vputs. 244 * 245 * Overall outline of ext2fs_lookup: 246 * 247 * check accessibility of directory 248 * look for name in cache, if found, then if at end of path 249 * and deleting or creating, drop it, else return name 250 * search for name in directory, to found or notfound 251 * notfound: 252 * if creating, return locked directory, leaving info on available slots 253 * else return error 254 * found: 255 * if at end of path and deleting, return information to allow delete 256 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 257 * inode and return info to allow rewrite 258 * if not at end, add name to cache; if at end and neither creating 259 * nor deleting, add name to cache 260 */ 261 int 262 ext2fs_lookup(void *v) 263 { 264 struct vop_lookup_v2_args /* { 265 struct vnode *a_dvp; 266 struct vnode **a_vpp; 267 struct componentname *a_cnp; 268 } */ *ap = v; 269 struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */ 270 struct inode *dp = VTOI(vdp); /* inode for directory being searched */ 271 struct buf *bp; /* a buffer of directory entries */ 272 struct ext2fs_direct *ep; /* the current directory entry */ 273 int entryoffsetinblock; /* offset of ep in bp's buffer */ 274 enum {NONE, COMPACT, FOUND} slotstatus; 275 doff_t slotoffset; /* offset of area with free space */ 276 int slotsize; /* size of area at slotoffset */ 277 int slotfreespace; /* amount of space free in slot */ 278 int slotneeded; /* size of the entry we're seeking */ 279 int numdirpasses; /* strategy for directory search */ 280 doff_t endsearch; /* offset to end directory search */ 281 doff_t prevoff; /* prev entry dp->i_offset */ 282 struct vnode *pdp; /* saved dp during symlink work */ 283 struct vnode *tdp; /* returned by VFS_VGET */ 284 doff_t enduseful; /* pointer past last used dir slot */ 285 u_long bmask; /* block offset mask */ 286 int namlen, error; 287 struct vnode **vpp = ap->a_vpp; 288 struct componentname *cnp = ap->a_cnp; 289 kauth_cred_t cred = cnp->cn_cred; 290 int flags; 291 int nameiop = cnp->cn_nameiop; 292 struct ufsmount *ump = dp->i_ump; 293 int dirblksiz = ump->um_dirblksiz; 294 ino_t foundino; 295 struct ufs_lookup_results *results; 296 297 flags = cnp->cn_flags; 298 299 bp = NULL; 300 slotoffset = -1; 301 *vpp = NULL; 302 303 /* 304 * Produce the auxiliary lookup results into i_crap. Increment 305 * its serial number so elsewhere we can tell if we're using 306 * stale results. This should not be done this way. XXX. 307 */ 308 results = &dp->i_crap; 309 dp->i_crapcounter++; 310 311 /* 312 * Check accessiblity of directory. 313 */ 314 if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) 315 return (error); 316 317 if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && 318 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 319 return (EROFS); 320 321 /* 322 * We now have a segment name to search for, and a directory to search. 323 * 324 * Before tediously performing a linear scan of the directory, 325 * check the name cache to see if the directory/name pair 326 * we are looking for is known already. 327 */ 328 if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, 329 cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) { 330 return *vpp == NULLVP ? ENOENT : 0; 331 } 332 333 /* 334 * Suppress search for slots unless creating 335 * file and at end of pathname, in which case 336 * we watch for a place to put the new file in 337 * case it doesn't already exist. 338 */ 339 slotstatus = FOUND; 340 slotfreespace = slotsize = slotneeded = 0; 341 if ((nameiop == CREATE || nameiop == RENAME) && 342 (flags & ISLASTCN)) { 343 slotstatus = NONE; 344 slotneeded = EXT2FS_DIRSIZ(cnp->cn_namelen); 345 } 346 347 /* 348 * If there is cached information on a previous search of 349 * this directory, pick up where we last left off. 350 * We cache only lookups as these are the most common 351 * and have the greatest payoff. Caching CREATE has little 352 * benefit as it usually must search the entire directory 353 * to determine that the entry does not exist. Caching the 354 * location of the last DELETE or RENAME has not reduced 355 * profiling time and hence has been removed in the interest 356 * of simplicity. 357 */ 358 bmask = vdp->v_mount->mnt_stat.f_iosize - 1; 359 if (nameiop != LOOKUP || results->ulr_diroff == 0 || 360 results->ulr_diroff >= ext2fs_size(dp)) { 361 entryoffsetinblock = 0; 362 results->ulr_offset = 0; 363 numdirpasses = 1; 364 } else { 365 results->ulr_offset = results->ulr_diroff; 366 if ((entryoffsetinblock = results->ulr_offset & bmask) && 367 (error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp))) 368 return (error); 369 numdirpasses = 2; 370 nchstats.ncs_2passes++; 371 } 372 prevoff = results->ulr_offset; 373 endsearch = roundup(ext2fs_size(dp), dirblksiz); 374 enduseful = 0; 375 376 searchloop: 377 while (results->ulr_offset < endsearch) { 378 if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) 379 preempt(); 380 /* 381 * If necessary, get the next directory block. 382 */ 383 if ((results->ulr_offset & bmask) == 0) { 384 if (bp != NULL) 385 brelse(bp, 0); 386 error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, 387 &bp); 388 if (error != 0) 389 return (error); 390 entryoffsetinblock = 0; 391 } 392 /* 393 * If still looking for a slot, and at a dirblksize 394 * boundary, have to start looking for free space again. 395 */ 396 if (slotstatus == NONE && 397 (entryoffsetinblock & (dirblksiz - 1)) == 0) { 398 slotoffset = -1; 399 slotfreespace = 0; 400 } 401 /* 402 * Get pointer to next entry. 403 * Full validation checks are slow, so we only check 404 * enough to insure forward progress through the 405 * directory. Complete checks can be run by patching 406 * "dirchk" to be true. 407 */ 408 KASSERT(bp != NULL); 409 ep = (struct ext2fs_direct *) 410 ((char *)bp->b_data + entryoffsetinblock); 411 if (ep->e2d_reclen == 0 || 412 (dirchk && 413 ext2fs_dirbadentry(vdp, ep, entryoffsetinblock))) { 414 int i; 415 416 ufs_dirbad(dp, results->ulr_offset, "mangled entry"); 417 i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); 418 results->ulr_offset += i; 419 entryoffsetinblock += i; 420 continue; 421 } 422 423 /* 424 * If an appropriate sized slot has not yet been found, 425 * check to see if one is available. Also accumulate space 426 * in the current block so that we can determine if 427 * compaction is viable. 428 */ 429 if (slotstatus != FOUND) { 430 int size = fs2h16(ep->e2d_reclen); 431 432 if (ep->e2d_ino != 0) 433 size -= EXT2FS_DIRSIZ(ep->e2d_namlen); 434 if (size > 0) { 435 if (size >= slotneeded) { 436 slotstatus = FOUND; 437 slotoffset = results->ulr_offset; 438 slotsize = fs2h16(ep->e2d_reclen); 439 } else if (slotstatus == NONE) { 440 slotfreespace += size; 441 if (slotoffset == -1) 442 slotoffset = results->ulr_offset; 443 if (slotfreespace >= slotneeded) { 444 slotstatus = COMPACT; 445 slotsize = results->ulr_offset + 446 fs2h16(ep->e2d_reclen) - 447 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 !memcmp(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 foundino = fs2h32(ep->e2d_ino); 467 results->ulr_reclen = fs2h16(ep->e2d_reclen); 468 goto found; 469 } 470 } 471 prevoff = results->ulr_offset; 472 results->ulr_offset += fs2h16(ep->e2d_reclen); 473 entryoffsetinblock += fs2h16(ep->e2d_reclen); 474 if (ep->e2d_ino) 475 enduseful = results->ulr_offset; 476 } 477 /* notfound: */ 478 /* 479 * If we started in the middle of the directory and failed 480 * to find our target, we must check the beginning as well. 481 */ 482 if (numdirpasses == 2) { 483 numdirpasses--; 484 results->ulr_offset = 0; 485 endsearch = results->ulr_diroff; 486 goto searchloop; 487 } 488 if (bp != NULL) 489 brelse(bp, 0); 490 /* 491 * If creating, and at end of pathname and current 492 * directory has not been removed, then can consider 493 * allowing file to be created. 494 */ 495 if ((nameiop == CREATE || nameiop == RENAME) && 496 (flags & ISLASTCN) && dp->i_e2fs_nlink != 0) { 497 /* 498 * Access for write is interpreted as allowing 499 * creation of files in the directory. 500 */ 501 error = VOP_ACCESS(vdp, VWRITE, cred); 502 if (error) 503 return (error); 504 /* 505 * Return an indication of where the new directory 506 * entry should be put. If we didn't find a slot, 507 * then set results->ulr_count to 0 indicating 508 * that the new slot belongs at the end of the 509 * directory. If we found a slot, then the new entry 510 * can be put in the range from results->ulr_offset to 511 * results->ulr_offset + results->ulr_count. 512 */ 513 if (slotstatus == NONE) { 514 results->ulr_offset = roundup(ext2fs_size(dp), dirblksiz); 515 results->ulr_count = 0; 516 enduseful = results->ulr_offset; 517 } else { 518 results->ulr_offset = slotoffset; 519 results->ulr_count = slotsize; 520 if (enduseful < slotoffset + slotsize) 521 enduseful = slotoffset + slotsize; 522 } 523 results->ulr_endoff = roundup(enduseful, dirblksiz); 524 #if 0 525 dp->i_flag |= IN_CHANGE | IN_UPDATE; 526 #endif 527 /* 528 * We return with the directory locked, so that 529 * the parameters we set up above will still be 530 * valid if we actually decide to do a direnter(). 531 * We return ni_vp == NULL to indicate that the entry 532 * does not currently exist; we leave a pointer to 533 * the (locked) directory inode in ndp->ni_dvp. 534 * 535 * NB - if the directory is unlocked, then this 536 * information cannot be used. 537 */ 538 return (EJUSTRETURN); 539 } 540 /* 541 * Insert name into cache (as non-existent) if appropriate. 542 */ 543 if (nameiop != CREATE) { 544 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, 545 cnp->cn_flags); 546 } 547 return ENOENT; 548 549 found: 550 if (numdirpasses == 2) 551 nchstats.ncs_pass2++; 552 /* 553 * Check that directory length properly reflects presence 554 * of this entry. 555 */ 556 if (results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen) > ext2fs_size(dp)) { 557 ufs_dirbad(dp, results->ulr_offset, "i_size too small"); 558 error = ext2fs_setsize(dp, 559 results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen)); 560 if (error) { 561 brelse(bp, 0); 562 return (error); 563 } 564 dp->i_flag |= IN_CHANGE | IN_UPDATE; 565 uvm_vnp_setsize(vdp, ext2fs_size(dp)); 566 } 567 brelse(bp, 0); 568 569 /* 570 * Found component in pathname. 571 * If the final component of path name, save information 572 * in the cache as to where the entry was found. 573 */ 574 if ((flags & ISLASTCN) && nameiop == LOOKUP) 575 results->ulr_diroff = results->ulr_offset &~ (dirblksiz - 1); 576 577 /* 578 * If deleting, and at end of pathname, return 579 * parameters which can be used to remove file. 580 * Lock the inode, being careful with ".". 581 */ 582 if (nameiop == DELETE && (flags & ISLASTCN)) { 583 /* 584 * Return pointer to current entry in results->ulr_offset, 585 * and distance past previous entry (if there 586 * is a previous entry in this block) in results->ulr_count. 587 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 588 */ 589 if ((results->ulr_offset & (dirblksiz - 1)) == 0) 590 results->ulr_count = 0; 591 else 592 results->ulr_count = results->ulr_offset - prevoff; 593 if (dp->i_number == foundino) { 594 vref(vdp); 595 tdp = vdp; 596 } else { 597 if (flags & ISDOTDOT) 598 VOP_UNLOCK(vdp); /* race to get the inode */ 599 error = VFS_VGET(vdp->v_mount, foundino, &tdp); 600 if (flags & ISDOTDOT) 601 vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY); 602 if (error) 603 return (error); 604 } 605 /* 606 * Write access to directory required to delete files. 607 */ 608 if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) { 609 if (dp->i_number == foundino) 610 vrele(tdp); 611 else 612 vput(tdp); 613 return (error); 614 } 615 /* 616 * If directory is "sticky", then user must own 617 * the directory, or the file in it, else she 618 * may not delete it (unless she's root). This 619 * implements append-only directories. 620 */ 621 if (dp->i_e2fs_mode & ISVTX) { 622 error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, 623 tdp, vdp, genfs_can_sticky(cred, dp->i_uid, 624 VTOI(tdp)->i_uid)); 625 if (error) { 626 if (dp->i_number == foundino) 627 vrele(tdp); 628 else 629 vput(tdp); 630 return (EPERM); 631 } 632 } 633 if (tdp != vdp) 634 VOP_UNLOCK(tdp); 635 *vpp = tdp; 636 return (0); 637 } 638 639 /* 640 * If rewriting (RENAME), return the inode and the 641 * information required to rewrite the present directory 642 * Must get inode of directory entry to verify it's a 643 * regular file, or empty directory. 644 */ 645 if (nameiop == RENAME && (flags & ISLASTCN)) { 646 error = VOP_ACCESS(vdp, VWRITE, cred); 647 if (error) 648 return (error); 649 /* 650 * Careful about locking second inode. 651 * This can only occur if the target is ".". 652 */ 653 if (dp->i_number == foundino) 654 return (EISDIR); 655 if (flags & ISDOTDOT) 656 VOP_UNLOCK(vdp); /* race to get the inode */ 657 error = VFS_VGET(vdp->v_mount, foundino, &tdp); 658 if (flags & ISDOTDOT) 659 vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY); 660 if (error) 661 return (error); 662 if (tdp != vdp) 663 VOP_UNLOCK(tdp); 664 *vpp = tdp; 665 return (0); 666 } 667 668 /* 669 * Step through the translation in the name. We do not `vput' the 670 * directory because we may need it again if a symbolic link 671 * is relative to the current directory. Instead we save it 672 * unlocked as "pdp". We must get the target inode before unlocking 673 * the directory to insure that the inode will not be removed 674 * before we get it. We prevent deadlock by always fetching 675 * inodes from the root, moving down the directory tree. Thus 676 * when following backward pointers ".." we must unlock the 677 * parent directory before getting the requested directory. 678 * There is a potential race condition here if both the current 679 * and parent directories are removed before the VFS_VGET for the 680 * inode associated with ".." returns. We hope that this occurs 681 * infrequently since we cannot avoid this race condition without 682 * implementing a sophisticated deadlock detection algorithm. 683 * Note also that this simple deadlock detection scheme will not 684 * work if the file system has any hard links other than ".." 685 * that point backwards in the directory structure. 686 */ 687 pdp = vdp; 688 if (flags & ISDOTDOT) { 689 VOP_UNLOCK(pdp); /* race to get the inode */ 690 error = VFS_VGET(vdp->v_mount, foundino, &tdp); 691 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY); 692 if (error) { 693 return (error); 694 } 695 *vpp = tdp; 696 } else if (dp->i_number == foundino) { 697 vref(vdp); /* we want ourself, ie "." */ 698 *vpp = vdp; 699 } else { 700 error = VFS_VGET(vdp->v_mount, foundino, &tdp); 701 if (error) 702 return (error); 703 *vpp = tdp; 704 } 705 706 /* 707 * Insert name into cache if appropriate. 708 */ 709 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); 710 if (*vpp != vdp) 711 VOP_UNLOCK(*vpp); 712 return 0; 713 } 714 715 /* 716 * Do consistency checking on a directory entry: 717 * record length must be multiple of 4 718 * entry must fit in rest of its dirblksize block 719 * record must be large enough to contain entry 720 * name is not longer than EXT2FS_MAXNAMLEN 721 * name must be as long as advertised, and null terminated 722 */ 723 /* 724 * changed so that it confirms to ext2fs_check_dir_entry 725 */ 726 static int 727 ext2fs_dirbadentry(struct vnode *dp, struct ext2fs_direct *de, 728 int entryoffsetinblock) 729 { 730 struct ufsmount *ump = VFSTOUFS(dp->v_mount); 731 int dirblksiz = ump->um_dirblksiz; 732 733 const char *error_msg = NULL; 734 int reclen = fs2h16(de->e2d_reclen); 735 int namlen = de->e2d_namlen; 736 737 if (reclen < EXT2FS_DIRSIZ(1)) /* e2d_namlen = 1 */ 738 error_msg = "rec_len is smaller than minimal"; 739 else if (reclen % 4 != 0) 740 error_msg = "rec_len % 4 != 0"; 741 else if (namlen > EXT2FS_MAXNAMLEN) 742 error_msg = "namlen > EXT2FS_MAXNAMLEN"; 743 else if (reclen < EXT2FS_DIRSIZ(namlen)) 744 error_msg = "reclen is too small for name_len"; 745 else if (entryoffsetinblock + reclen > dirblksiz) 746 error_msg = "directory entry across blocks"; 747 else if (fs2h32(de->e2d_ino) > 748 VTOI(dp)->i_e2fs->e2fs.e2fs_icount) 749 error_msg = "inode out of bounds"; 750 751 if (error_msg != NULL) { 752 printf( "bad directory entry: %s\n" 753 "offset=%d, inode=%lu, rec_len=%d, name_len=%d \n", 754 error_msg, entryoffsetinblock, 755 (unsigned long) fs2h32(de->e2d_ino), 756 reclen, namlen); 757 panic("ext2fs_dirbadentry"); 758 } 759 return error_msg == NULL ? 0 : 1; 760 } 761 762 /* 763 * Write a directory entry after a call to namei, using the parameters 764 * that it left in nameidata. The argument ip is the inode which the new 765 * directory entry will refer to. Dvp is a pointer to the directory to 766 * be written, which was left locked by namei. Remaining parameters 767 * (ulr_offset, ulr_count) indicate how the space for the new 768 * entry is to be obtained. 769 */ 770 int 771 ext2fs_direnter(struct inode *ip, struct vnode *dvp, 772 const struct ufs_lookup_results *ulr, 773 struct componentname *cnp) 774 { 775 struct ext2fs_direct *ep, *nep; 776 struct inode *dp; 777 struct buf *bp; 778 struct ext2fs_direct newdir; 779 struct iovec aiov; 780 struct uio auio; 781 u_int dsize; 782 int error, loc, newentrysize, spacefree; 783 char *dirbuf; 784 struct ufsmount *ump = VFSTOUFS(dvp->v_mount); 785 int dirblksiz = ump->um_dirblksiz; 786 787 dp = VTOI(dvp); 788 789 newdir.e2d_ino = h2fs32(ip->i_number); 790 newdir.e2d_namlen = cnp->cn_namelen; 791 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 && 792 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) { 793 newdir.e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); 794 } else { 795 newdir.e2d_type = 0; 796 } 797 memcpy(newdir.e2d_name, cnp->cn_nameptr, (unsigned)cnp->cn_namelen + 1); 798 newentrysize = EXT2FS_DIRSIZ(cnp->cn_namelen); 799 if (ulr->ulr_count == 0) { 800 /* 801 * If ulr_count is 0, then namei could find no 802 * space in the directory. Here, ulr_offset will 803 * be on a directory block boundary and we will write the 804 * new entry into a fresh block. 805 */ 806 if (ulr->ulr_offset & (dirblksiz - 1)) 807 panic("ext2fs_direnter: newblk"); 808 auio.uio_offset = ulr->ulr_offset; 809 newdir.e2d_reclen = h2fs16(dirblksiz); 810 auio.uio_resid = newentrysize; 811 aiov.iov_len = newentrysize; 812 aiov.iov_base = (void *)&newdir; 813 auio.uio_iov = &aiov; 814 auio.uio_iovcnt = 1; 815 auio.uio_rw = UIO_WRITE; 816 UIO_SETUP_SYSSPACE(&auio); 817 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred); 818 if (dirblksiz > dvp->v_mount->mnt_stat.f_bsize) 819 /* XXX should grow with balloc() */ 820 panic("ext2fs_direnter: frag size"); 821 else if (!error) { 822 error = ext2fs_setsize(dp, 823 roundup(ext2fs_size(dp), dirblksiz)); 824 if (error) 825 return (error); 826 dp->i_flag |= IN_CHANGE; 827 uvm_vnp_setsize(dvp, ext2fs_size(dp)); 828 } 829 return (error); 830 } 831 832 /* 833 * If ulr_count is non-zero, then namei found space 834 * for the new entry in the range ulr_offset to 835 * ulr_offset + ulr_count in the directory. 836 * To use this space, we may have to compact the entries located 837 * there, by copying them together towards the beginning of the 838 * block, leaving the free space in one usable chunk at the end. 839 */ 840 841 /* 842 * Get the block containing the space for the new directory entry. 843 */ 844 if ((error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp)) != 0) 845 return (error); 846 /* 847 * Find space for the new entry. In the simple case, the entry at 848 * offset base will have the space. If it does not, then namei 849 * arranged that compacting the region ulr_offset to 850 * ulr_offset + ulr_count would yield the 851 * space. 852 */ 853 ep = (struct ext2fs_direct *)dirbuf; 854 dsize = EXT2FS_DIRSIZ(ep->e2d_namlen); 855 spacefree = fs2h16(ep->e2d_reclen) - dsize; 856 for (loc = fs2h16(ep->e2d_reclen); loc < ulr->ulr_count; ) { 857 nep = (struct ext2fs_direct *)(dirbuf + loc); 858 if (ep->e2d_ino) { 859 /* trim the existing slot */ 860 ep->e2d_reclen = h2fs16(dsize); 861 ep = (struct ext2fs_direct *)((char *)ep + dsize); 862 } else { 863 /* overwrite; nothing there; header is ours */ 864 spacefree += dsize; 865 } 866 dsize = EXT2FS_DIRSIZ(nep->e2d_namlen); 867 spacefree += fs2h16(nep->e2d_reclen) - dsize; 868 loc += fs2h16(nep->e2d_reclen); 869 memcpy((void *)ep, (void *)nep, dsize); 870 } 871 /* 872 * Update the pointer fields in the previous entry (if any), 873 * copy in the new entry, and write out the block. 874 */ 875 if (ep->e2d_ino == 0) { 876 #ifdef DIAGNOSTIC 877 if (spacefree + dsize < newentrysize) 878 panic("ext2fs_direnter: compact1"); 879 #endif 880 newdir.e2d_reclen = h2fs16(spacefree + dsize); 881 } else { 882 #ifdef DIAGNOSTIC 883 if (spacefree < newentrysize) { 884 printf("ext2fs_direnter: compact2 %u %u", 885 (u_int)spacefree, (u_int)newentrysize); 886 panic("ext2fs_direnter: compact2"); 887 } 888 #endif 889 newdir.e2d_reclen = h2fs16(spacefree); 890 ep->e2d_reclen = h2fs16(dsize); 891 ep = (struct ext2fs_direct *)((char *)ep + dsize); 892 } 893 memcpy((void *)ep, (void *)&newdir, (u_int)newentrysize); 894 error = VOP_BWRITE(bp->b_vp, bp); 895 dp->i_flag |= IN_CHANGE | IN_UPDATE; 896 if (!error && ulr->ulr_endoff && ulr->ulr_endoff < ext2fs_size(dp)) 897 error = ext2fs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, 898 cnp->cn_cred); 899 return (error); 900 } 901 902 /* 903 * Remove a directory entry after a call to namei, using 904 * the auxiliary results it provided. The entry 905 * ulr_offset contains the offset into the directory of the 906 * entry to be eliminated. The ulr_count field contains the 907 * size of the previous record in the directory. If this 908 * is 0, the first entry is being deleted, so we need only 909 * zero the inode number to mark the entry as free. If the 910 * entry is not the first in the directory, we must reclaim 911 * the space of the now empty record by adding the record size 912 * to the size of the previous entry. 913 */ 914 int 915 ext2fs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr, 916 struct componentname *cnp) 917 { 918 struct inode *dp; 919 struct ext2fs_direct *ep; 920 struct buf *bp; 921 int error; 922 923 dp = VTOI(dvp); 924 925 if (ulr->ulr_count == 0) { 926 /* 927 * First entry in block: set d_ino to zero. 928 */ 929 error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, 930 (void *)&ep, &bp); 931 if (error != 0) 932 return (error); 933 ep->e2d_ino = 0; 934 error = VOP_BWRITE(bp->b_vp, bp); 935 dp->i_flag |= IN_CHANGE | IN_UPDATE; 936 return (error); 937 } 938 /* 939 * Collapse new free space into previous entry. 940 */ 941 error = ext2fs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count), 942 (void *)&ep, &bp); 943 if (error != 0) 944 return (error); 945 ep->e2d_reclen = h2fs16(fs2h16(ep->e2d_reclen) + ulr->ulr_reclen); 946 error = VOP_BWRITE(bp->b_vp, bp); 947 dp->i_flag |= IN_CHANGE | IN_UPDATE; 948 return (error); 949 } 950 951 /* 952 * Rewrite an existing directory entry to point at the inode 953 * supplied. The parameters describing the directory entry are 954 * set up by a call to namei. 955 */ 956 int 957 ext2fs_dirrewrite(struct inode *dp, const struct ufs_lookup_results *ulr, 958 struct inode *ip, struct componentname *cnp) 959 { 960 struct buf *bp; 961 struct ext2fs_direct *ep; 962 struct vnode *vdp = ITOV(dp); 963 int error; 964 965 error = ext2fs_blkatoff(vdp, (off_t)ulr->ulr_offset, (void *)&ep, &bp); 966 if (error != 0) 967 return (error); 968 ep->e2d_ino = h2fs32(ip->i_number); 969 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 && 970 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) { 971 ep->e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); 972 } else { 973 ep->e2d_type = 0; 974 } 975 error = VOP_BWRITE(bp->b_vp, bp); 976 dp->i_flag |= IN_CHANGE | IN_UPDATE; 977 return (error); 978 } 979 980 /* 981 * Check if a directory is empty or not. 982 * Inode supplied must be locked. 983 * 984 * Using a struct dirtemplate here is not precisely 985 * what we want, but better than using a struct ext2fs_direct. 986 * 987 * NB: does not handle corrupted directories. 988 */ 989 int 990 ext2fs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) 991 { 992 off_t off; 993 struct ext2fs_dirtemplate dbuf; 994 struct ext2fs_direct *dp = (struct ext2fs_direct *)&dbuf; 995 int error, namlen; 996 size_t count; 997 998 #define MINDIRSIZ (sizeof (struct ext2fs_dirtemplate) / 2) 999 1000 for (off = 0; off < ext2fs_size(ip); off += fs2h16(dp->e2d_reclen)) { 1001 error = vn_rdwr(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ, off, 1002 UIO_SYSSPACE, IO_NODELOCKED, cred, &count, NULL); 1003 /* 1004 * Since we read MINDIRSIZ, residual must 1005 * be 0 unless we're at end of file. 1006 */ 1007 if (error || count != 0) 1008 return (0); 1009 /* avoid infinite loops */ 1010 if (dp->e2d_reclen == 0) 1011 return (0); 1012 /* skip empty entries */ 1013 if (dp->e2d_ino == 0) 1014 continue; 1015 /* accept only "." and ".." */ 1016 namlen = dp->e2d_namlen; 1017 if (namlen > 2) 1018 return (0); 1019 if (dp->e2d_name[0] != '.') 1020 return (0); 1021 /* 1022 * At this point namlen must be 1 or 2. 1023 * 1 implies ".", 2 implies ".." if second 1024 * char is also "." 1025 */ 1026 if (namlen == 1) 1027 continue; 1028 if (dp->e2d_name[1] == '.' && fs2h32(dp->e2d_ino) == parentino) 1029 continue; 1030 return (0); 1031 } 1032 return (1); 1033 } 1034 1035 /* 1036 * Check if source directory is in the path of the target directory. 1037 * Target is supplied locked, source is unlocked. 1038 * The target is always vput before returning. 1039 */ 1040 int 1041 ext2fs_checkpath(struct inode *source, struct inode *target, 1042 kauth_cred_t cred) 1043 { 1044 struct vnode *vp; 1045 int error, rootino, namlen; 1046 struct ext2fs_dirtemplate dirbuf; 1047 uint32_t ino; 1048 1049 vp = ITOV(target); 1050 if (target->i_number == source->i_number) { 1051 error = EEXIST; 1052 goto out; 1053 } 1054 rootino = UFS_ROOTINO; 1055 error = 0; 1056 if (target->i_number == rootino) 1057 goto out; 1058 1059 for (;;) { 1060 if (vp->v_type != VDIR) { 1061 error = ENOTDIR; 1062 break; 1063 } 1064 error = vn_rdwr(UIO_READ, vp, (void *)&dirbuf, 1065 sizeof (struct ext2fs_dirtemplate), (off_t)0, 1066 UIO_SYSSPACE, IO_NODELOCKED, cred, (size_t *)0, 1067 NULL); 1068 if (error != 0) 1069 break; 1070 namlen = dirbuf.dotdot_namlen; 1071 if (namlen != 2 || 1072 dirbuf.dotdot_name[0] != '.' || 1073 dirbuf.dotdot_name[1] != '.') { 1074 error = ENOTDIR; 1075 break; 1076 } 1077 ino = fs2h32(dirbuf.dotdot_ino); 1078 if (ino == source->i_number) { 1079 error = EINVAL; 1080 break; 1081 } 1082 if (ino == rootino) 1083 break; 1084 vput(vp); 1085 error = VFS_VGET(vp->v_mount, ino, &vp); 1086 if (error != 0) { 1087 vp = NULL; 1088 break; 1089 } 1090 } 1091 1092 out: 1093 if (error == ENOTDIR) { 1094 printf("checkpath: .. not a directory\n"); 1095 panic("checkpath"); 1096 } 1097 if (vp != NULL) 1098 vput(vp); 1099 return (error); 1100 } 1101