ext2fs_lookup.c revision 1.79
1/* $NetBSD: ext2fs_lookup.c,v 1.79 2016/01/12 21:29:29 riastradh 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 1.79 2016/01/12 21:29:29 riastradh 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 76extern int dirchk; 77 78static void ext2fs_dirconv2ffs(struct ext2fs_direct *e2dir, 79 struct dirent *ffsdir); 80static 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 */ 94static void 95ext2fs_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 */ 131int 132ext2fs_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 = UFS_BUFRD(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 */ 261int 262ext2fs_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 *tdp; /* returned by vcache_get */ 283 doff_t enduseful; /* pointer past last used dir slot */ 284 u_long bmask; /* block offset mask */ 285 int namlen, error; 286 struct vnode **vpp = ap->a_vpp; 287 struct componentname *cnp = ap->a_cnp; 288 kauth_cred_t cred = cnp->cn_cred; 289 int flags; 290 int nameiop = cnp->cn_nameiop; 291 struct ufsmount *ump = dp->i_ump; 292 int dirblksiz = ump->um_dirblksiz; 293 ino_t foundino; 294 struct ufs_lookup_results *results; 295 296 flags = cnp->cn_flags; 297 298 bp = NULL; 299 slotoffset = -1; 300 *vpp = NULL; 301 302 /* 303 * Produce the auxiliary lookup results into i_crap. Increment 304 * its serial number so elsewhere we can tell if we're using 305 * stale results. This should not be done this way. XXX. 306 */ 307 results = &dp->i_crap; 308 dp->i_crapcounter++; 309 310 /* 311 * Check accessiblity of directory. 312 */ 313 if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0) 314 return (error); 315 316 if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) && 317 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) 318 return (EROFS); 319 320 /* 321 * We now have a segment name to search for, and a directory to search. 322 * 323 * Before tediously performing a linear scan of the directory, 324 * check the name cache to see if the directory/name pair 325 * we are looking for is known already. 326 */ 327 if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen, 328 cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) { 329 return *vpp == NULLVP ? ENOENT : 0; 330 } 331 332 /* 333 * Suppress search for slots unless creating 334 * file and at end of pathname, in which case 335 * we watch for a place to put the new file in 336 * case it doesn't already exist. 337 */ 338 slotstatus = FOUND; 339 slotfreespace = slotsize = slotneeded = 0; 340 if ((nameiop == CREATE || nameiop == RENAME) && 341 (flags & ISLASTCN)) { 342 slotstatus = NONE; 343 slotneeded = EXT2FS_DIRSIZ(cnp->cn_namelen); 344 } 345 346 /* 347 * If there is cached information on a previous search of 348 * this directory, pick up where we last left off. 349 * We cache only lookups as these are the most common 350 * and have the greatest payoff. Caching CREATE has little 351 * benefit as it usually must search the entire directory 352 * to determine that the entry does not exist. Caching the 353 * location of the last DELETE or RENAME has not reduced 354 * profiling time and hence has been removed in the interest 355 * of simplicity. 356 */ 357 bmask = vdp->v_mount->mnt_stat.f_iosize - 1; 358 if (nameiop != LOOKUP || results->ulr_diroff == 0 || 359 results->ulr_diroff >= ext2fs_size(dp)) { 360 entryoffsetinblock = 0; 361 results->ulr_offset = 0; 362 numdirpasses = 1; 363 } else { 364 results->ulr_offset = results->ulr_diroff; 365 if ((entryoffsetinblock = results->ulr_offset & bmask) && 366 (error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp))) 367 return (error); 368 numdirpasses = 2; 369 namecache_count_2passes(); 370 } 371 prevoff = results->ulr_offset; 372 endsearch = roundup(ext2fs_size(dp), dirblksiz); 373 enduseful = 0; 374 375searchloop: 376 while (results->ulr_offset < endsearch) { 377 if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) 378 preempt(); 379 /* 380 * If necessary, get the next directory block. 381 */ 382 if ((results->ulr_offset & bmask) == 0) { 383 if (bp != NULL) 384 brelse(bp, 0); 385 error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, 386 &bp); 387 if (error != 0) 388 return (error); 389 entryoffsetinblock = 0; 390 } 391 /* 392 * If still looking for a slot, and at a dirblksize 393 * boundary, have to start looking for free space again. 394 */ 395 if (slotstatus == NONE && 396 (entryoffsetinblock & (dirblksiz - 1)) == 0) { 397 slotoffset = -1; 398 slotfreespace = 0; 399 } 400 /* 401 * Get pointer to next entry. 402 * Full validation checks are slow, so we only check 403 * enough to insure forward progress through the 404 * directory. Complete checks can be run by patching 405 * "dirchk" to be true. 406 */ 407 KASSERT(bp != NULL); 408 ep = (struct ext2fs_direct *) 409 ((char *)bp->b_data + entryoffsetinblock); 410 if (ep->e2d_reclen == 0 || 411 (dirchk && 412 ext2fs_dirbadentry(vdp, ep, entryoffsetinblock))) { 413 int i; 414 415 ufs_dirbad(dp, results->ulr_offset, "mangled entry"); 416 i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1)); 417 results->ulr_offset += i; 418 entryoffsetinblock += i; 419 continue; 420 } 421 422 /* 423 * If an appropriate sized slot has not yet been found, 424 * check to see if one is available. Also accumulate space 425 * in the current block so that we can determine if 426 * compaction is viable. 427 */ 428 if (slotstatus != FOUND) { 429 int size = fs2h16(ep->e2d_reclen); 430 431 if (ep->e2d_ino != 0) 432 size -= EXT2FS_DIRSIZ(ep->e2d_namlen); 433 if (size > 0) { 434 if (size >= slotneeded) { 435 slotstatus = FOUND; 436 slotoffset = results->ulr_offset; 437 slotsize = fs2h16(ep->e2d_reclen); 438 } else if (slotstatus == NONE) { 439 slotfreespace += size; 440 if (slotoffset == -1) 441 slotoffset = results->ulr_offset; 442 if (slotfreespace >= slotneeded) { 443 slotstatus = COMPACT; 444 slotsize = results->ulr_offset + 445 fs2h16(ep->e2d_reclen) - 446 slotoffset; 447 } 448 } 449 } 450 } 451 452 /* 453 * Check for a name match. 454 */ 455 if (ep->e2d_ino) { 456 namlen = ep->e2d_namlen; 457 if (namlen == cnp->cn_namelen && 458 !memcmp(cnp->cn_nameptr, ep->e2d_name, 459 (unsigned)namlen)) { 460 /* 461 * Save directory entry's inode number and 462 * reclen in ndp->ni_ufs area, and release 463 * directory buffer. 464 */ 465 foundino = fs2h32(ep->e2d_ino); 466 results->ulr_reclen = fs2h16(ep->e2d_reclen); 467 goto found; 468 } 469 } 470 prevoff = results->ulr_offset; 471 results->ulr_offset += fs2h16(ep->e2d_reclen); 472 entryoffsetinblock += fs2h16(ep->e2d_reclen); 473 if (ep->e2d_ino) 474 enduseful = results->ulr_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 results->ulr_offset = 0; 484 endsearch = results->ulr_diroff; 485 goto searchloop; 486 } 487 if (bp != NULL) 488 brelse(bp, 0); 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_e2fs_nlink != 0) { 496 /* 497 * Access for write is interpreted as allowing 498 * creation of files in the directory. 499 */ 500 error = VOP_ACCESS(vdp, VWRITE, cred); 501 if (error) 502 return (error); 503 /* 504 * Return an indication of where the new directory 505 * entry should be put. If we didn't find a slot, 506 * then set results->ulr_count to 0 indicating 507 * that the new slot belongs at the end of the 508 * directory. If we found a slot, then the new entry 509 * can be put in the range from results->ulr_offset to 510 * results->ulr_offset + results->ulr_count. 511 */ 512 if (slotstatus == NONE) { 513 results->ulr_offset = roundup(ext2fs_size(dp), dirblksiz); 514 results->ulr_count = 0; 515 enduseful = results->ulr_offset; 516 } else { 517 results->ulr_offset = slotoffset; 518 results->ulr_count = slotsize; 519 if (enduseful < slotoffset + slotsize) 520 enduseful = slotoffset + slotsize; 521 } 522 results->ulr_endoff = roundup(enduseful, dirblksiz); 523#if 0 524 dp->i_flag |= IN_CHANGE | IN_UPDATE; 525#endif 526 /* 527 * We return with the directory locked, so that 528 * the parameters we set up above will still be 529 * valid if we actually decide to do a direnter(). 530 * We return ni_vp == NULL to indicate that the entry 531 * does not currently exist; we leave a pointer to 532 * the (locked) directory inode in ndp->ni_dvp. 533 * 534 * NB - if the directory is unlocked, then this 535 * information cannot be used. 536 */ 537 return (EJUSTRETURN); 538 } 539 /* 540 * Insert name into cache (as non-existent) if appropriate. 541 */ 542 if (nameiop != CREATE) { 543 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, 544 cnp->cn_flags); 545 } 546 return ENOENT; 547 548found: 549 if (numdirpasses == 2) 550 namecache_count_pass2(); 551 /* 552 * Check that directory length properly reflects presence 553 * of this entry. 554 */ 555 if (results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen) > ext2fs_size(dp)) { 556 ufs_dirbad(dp, results->ulr_offset, "i_size too small"); 557 error = ext2fs_setsize(dp, 558 results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen)); 559 if (error) { 560 brelse(bp, 0); 561 return (error); 562 } 563 dp->i_flag |= IN_CHANGE | IN_UPDATE; 564 uvm_vnp_setsize(vdp, ext2fs_size(dp)); 565 } 566 brelse(bp, 0); 567 568 /* 569 * Found component in pathname. 570 * If the final component of path name, save information 571 * in the cache as to where the entry was found. 572 */ 573 if ((flags & ISLASTCN) && nameiop == LOOKUP) 574 results->ulr_diroff = results->ulr_offset &~ (dirblksiz - 1); 575 576 /* 577 * If deleting, and at end of pathname, return 578 * parameters which can be used to remove file. 579 * Lock the inode, being careful with ".". 580 */ 581 if (nameiop == DELETE && (flags & ISLASTCN)) { 582 /* 583 * Return pointer to current entry in results->ulr_offset, 584 * and distance past previous entry (if there 585 * is a previous entry in this block) in results->ulr_count. 586 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 587 */ 588 if ((results->ulr_offset & (dirblksiz - 1)) == 0) 589 results->ulr_count = 0; 590 else 591 results->ulr_count = results->ulr_offset - prevoff; 592 if (dp->i_number == foundino) { 593 vref(vdp); 594 tdp = vdp; 595 } else { 596 error = vcache_get(vdp->v_mount, 597 &foundino, sizeof(foundino), &tdp); 598 if (error) 599 return (error); 600 } 601 /* 602 * Write access to directory required to delete files. 603 */ 604 if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) { 605 vrele(tdp); 606 return (error); 607 } 608 /* 609 * If directory is "sticky", then user must own 610 * the directory, or the file in it, else she 611 * may not delete it (unless she's root). This 612 * implements append-only directories. 613 */ 614 if (dp->i_e2fs_mode & ISVTX) { 615 error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE, 616 tdp, vdp, genfs_can_sticky(cred, dp->i_uid, 617 VTOI(tdp)->i_uid)); 618 if (error) { 619 vrele(tdp); 620 return (EPERM); 621 } 622 } 623 *vpp = tdp; 624 return (0); 625 } 626 627 /* 628 * If rewriting (RENAME), return the inode and the 629 * information required to rewrite the present directory 630 * Must get inode of directory entry to verify it's a 631 * regular file, or empty directory. 632 */ 633 if (nameiop == RENAME && (flags & ISLASTCN)) { 634 error = VOP_ACCESS(vdp, VWRITE, cred); 635 if (error) 636 return (error); 637 /* 638 * Careful about locking second inode. 639 * This can only occur if the target is ".". 640 */ 641 if (dp->i_number == foundino) 642 return (EISDIR); 643 error = vcache_get(vdp->v_mount, 644 &foundino, sizeof(foundino), &tdp); 645 if (error) 646 return (error); 647 *vpp = tdp; 648 return (0); 649 } 650 651 if (dp->i_number == foundino) { 652 vref(vdp); /* we want ourself, ie "." */ 653 *vpp = vdp; 654 } else { 655 error = vcache_get(vdp->v_mount, 656 &foundino, sizeof(foundino), &tdp); 657 if (error) 658 return (error); 659 *vpp = tdp; 660 } 661 662 /* 663 * Insert name into cache if appropriate. 664 */ 665 cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags); 666 return 0; 667} 668 669/* 670 * Do consistency checking on a directory entry: 671 * record length must be multiple of 4 672 * entry must fit in rest of its dirblksize block 673 * record must be large enough to contain entry 674 * name is not longer than EXT2FS_MAXNAMLEN 675 * name must be as long as advertised, and null terminated 676 */ 677/* 678 * changed so that it confirms to ext2fs_check_dir_entry 679 */ 680static int 681ext2fs_dirbadentry(struct vnode *dp, struct ext2fs_direct *de, 682 int entryoffsetinblock) 683{ 684 struct ufsmount *ump = VFSTOUFS(dp->v_mount); 685 int dirblksiz = ump->um_dirblksiz; 686 687 const char *error_msg = NULL; 688 int reclen = fs2h16(de->e2d_reclen); 689 int namlen = de->e2d_namlen; 690 691 if (reclen < EXT2FS_DIRSIZ(1)) /* e2d_namlen = 1 */ 692 error_msg = "rec_len is smaller than minimal"; 693 else if (reclen % 4 != 0) 694 error_msg = "rec_len % 4 != 0"; 695 else if (namlen > EXT2FS_MAXNAMLEN) 696 error_msg = "namlen > EXT2FS_MAXNAMLEN"; 697 else if (reclen < EXT2FS_DIRSIZ(namlen)) 698 error_msg = "reclen is too small for name_len"; 699 else if (entryoffsetinblock + reclen > dirblksiz) 700 error_msg = "directory entry across blocks"; 701 else if (fs2h32(de->e2d_ino) > 702 VTOI(dp)->i_e2fs->e2fs.e2fs_icount) 703 error_msg = "inode out of bounds"; 704 705 if (error_msg != NULL) { 706 printf( "bad directory entry: %s\n" 707 "offset=%d, inode=%lu, rec_len=%d, name_len=%d \n", 708 error_msg, entryoffsetinblock, 709 (unsigned long) fs2h32(de->e2d_ino), 710 reclen, namlen); 711 panic("ext2fs_dirbadentry"); 712 } 713 return error_msg == NULL ? 0 : 1; 714} 715 716/* 717 * Write a directory entry after a call to namei, using the parameters 718 * that it left in nameidata. The argument ip is the inode which the new 719 * directory entry will refer to. Dvp is a pointer to the directory to 720 * be written, which was left locked by namei. Remaining parameters 721 * (ulr_offset, ulr_count) indicate how the space for the new 722 * entry is to be obtained. 723 */ 724int 725ext2fs_direnter(struct inode *ip, struct vnode *dvp, 726 const struct ufs_lookup_results *ulr, 727 struct componentname *cnp) 728{ 729 struct ext2fs_direct *ep, *nep; 730 struct inode *dp; 731 struct buf *bp; 732 struct ext2fs_direct newdir; 733 struct iovec aiov; 734 struct uio auio; 735 u_int dsize; 736 int error, loc, newentrysize, spacefree; 737 char *dirbuf; 738 struct ufsmount *ump = VFSTOUFS(dvp->v_mount); 739 int dirblksiz = ump->um_dirblksiz; 740 741 dp = VTOI(dvp); 742 743 newdir.e2d_ino = h2fs32(ip->i_number); 744 newdir.e2d_namlen = cnp->cn_namelen; 745 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 && 746 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) { 747 newdir.e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); 748 } else { 749 newdir.e2d_type = 0; 750 } 751 memcpy(newdir.e2d_name, cnp->cn_nameptr, (unsigned)cnp->cn_namelen + 1); 752 newentrysize = EXT2FS_DIRSIZ(cnp->cn_namelen); 753 if (ulr->ulr_count == 0) { 754 /* 755 * If ulr_count is 0, then namei could find no 756 * space in the directory. Here, ulr_offset will 757 * be on a directory block boundary and we will write the 758 * new entry into a fresh block. 759 */ 760 if (ulr->ulr_offset & (dirblksiz - 1)) 761 panic("ext2fs_direnter: newblk"); 762 auio.uio_offset = ulr->ulr_offset; 763 newdir.e2d_reclen = h2fs16(dirblksiz); 764 auio.uio_resid = newentrysize; 765 aiov.iov_len = newentrysize; 766 aiov.iov_base = (void *)&newdir; 767 auio.uio_iov = &aiov; 768 auio.uio_iovcnt = 1; 769 auio.uio_rw = UIO_WRITE; 770 UIO_SETUP_SYSSPACE(&auio); 771 error = ext2fs_bufwr(dvp, &auio, IO_SYNC, cnp->cn_cred); 772 if (dirblksiz > dvp->v_mount->mnt_stat.f_bsize) 773 /* XXX should grow with balloc() */ 774 panic("ext2fs_direnter: frag size"); 775 else if (!error) { 776 error = ext2fs_setsize(dp, 777 roundup(ext2fs_size(dp), dirblksiz)); 778 if (error) 779 return (error); 780 dp->i_flag |= IN_CHANGE; 781 uvm_vnp_setsize(dvp, ext2fs_size(dp)); 782 } 783 return (error); 784 } 785 786 /* 787 * If ulr_count is non-zero, then namei found space 788 * for the new entry in the range ulr_offset to 789 * ulr_offset + ulr_count in the directory. 790 * To use this space, we may have to compact the entries located 791 * there, by copying them together towards the beginning of the 792 * block, leaving the free space in one usable chunk at the end. 793 */ 794 795 /* 796 * Get the block containing the space for the new directory entry. 797 */ 798 if ((error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp)) != 0) 799 return (error); 800 /* 801 * Find space for the new entry. In the simple case, the entry at 802 * offset base will have the space. If it does not, then namei 803 * arranged that compacting the region ulr_offset to 804 * ulr_offset + ulr_count would yield the 805 * space. 806 */ 807 ep = (struct ext2fs_direct *)dirbuf; 808 dsize = EXT2FS_DIRSIZ(ep->e2d_namlen); 809 spacefree = fs2h16(ep->e2d_reclen) - dsize; 810 for (loc = fs2h16(ep->e2d_reclen); loc < ulr->ulr_count; ) { 811 nep = (struct ext2fs_direct *)(dirbuf + loc); 812 if (ep->e2d_ino) { 813 /* trim the existing slot */ 814 ep->e2d_reclen = h2fs16(dsize); 815 ep = (struct ext2fs_direct *)((char *)ep + dsize); 816 } else { 817 /* overwrite; nothing there; header is ours */ 818 spacefree += dsize; 819 } 820 dsize = EXT2FS_DIRSIZ(nep->e2d_namlen); 821 spacefree += fs2h16(nep->e2d_reclen) - dsize; 822 loc += fs2h16(nep->e2d_reclen); 823 memcpy((void *)ep, (void *)nep, dsize); 824 } 825 /* 826 * Update the pointer fields in the previous entry (if any), 827 * copy in the new entry, and write out the block. 828 */ 829 if (ep->e2d_ino == 0) { 830#ifdef DIAGNOSTIC 831 if (spacefree + dsize < newentrysize) 832 panic("ext2fs_direnter: compact1"); 833#endif 834 newdir.e2d_reclen = h2fs16(spacefree + dsize); 835 } else { 836#ifdef DIAGNOSTIC 837 if (spacefree < newentrysize) { 838 printf("ext2fs_direnter: compact2 %u %u", 839 (u_int)spacefree, (u_int)newentrysize); 840 panic("ext2fs_direnter: compact2"); 841 } 842#endif 843 newdir.e2d_reclen = h2fs16(spacefree); 844 ep->e2d_reclen = h2fs16(dsize); 845 ep = (struct ext2fs_direct *)((char *)ep + dsize); 846 } 847 memcpy((void *)ep, (void *)&newdir, (u_int)newentrysize); 848 error = VOP_BWRITE(bp->b_vp, bp); 849 dp->i_flag |= IN_CHANGE | IN_UPDATE; 850 if (!error && ulr->ulr_endoff && ulr->ulr_endoff < ext2fs_size(dp)) 851 error = ext2fs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, 852 cnp->cn_cred); 853 return (error); 854} 855 856/* 857 * Remove a directory entry after a call to namei, using 858 * the auxiliary results it provided. The entry 859 * ulr_offset contains the offset into the directory of the 860 * entry to be eliminated. The ulr_count field contains the 861 * size of the previous record in the directory. If this 862 * is 0, the first entry is being deleted, so we need only 863 * zero the inode number to mark the entry as free. If the 864 * entry is not the first in the directory, we must reclaim 865 * the space of the now empty record by adding the record size 866 * to the size of the previous entry. 867 */ 868int 869ext2fs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr, 870 struct componentname *cnp) 871{ 872 struct inode *dp; 873 struct ext2fs_direct *ep; 874 struct buf *bp; 875 int error; 876 877 dp = VTOI(dvp); 878 879 if (ulr->ulr_count == 0) { 880 /* 881 * First entry in block: set d_ino to zero. 882 */ 883 error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, 884 (void *)&ep, &bp); 885 if (error != 0) 886 return (error); 887 ep->e2d_ino = 0; 888 error = VOP_BWRITE(bp->b_vp, bp); 889 dp->i_flag |= IN_CHANGE | IN_UPDATE; 890 return (error); 891 } 892 /* 893 * Collapse new free space into previous entry. 894 */ 895 error = ext2fs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count), 896 (void *)&ep, &bp); 897 if (error != 0) 898 return (error); 899 ep->e2d_reclen = h2fs16(fs2h16(ep->e2d_reclen) + ulr->ulr_reclen); 900 error = VOP_BWRITE(bp->b_vp, bp); 901 dp->i_flag |= IN_CHANGE | IN_UPDATE; 902 return (error); 903} 904 905/* 906 * Rewrite an existing directory entry to point at the inode 907 * supplied. The parameters describing the directory entry are 908 * set up by a call to namei. 909 */ 910int 911ext2fs_dirrewrite(struct inode *dp, const struct ufs_lookup_results *ulr, 912 struct inode *ip, struct componentname *cnp) 913{ 914 struct buf *bp; 915 struct ext2fs_direct *ep; 916 struct vnode *vdp = ITOV(dp); 917 int error; 918 919 error = ext2fs_blkatoff(vdp, (off_t)ulr->ulr_offset, (void *)&ep, &bp); 920 if (error != 0) 921 return (error); 922 ep->e2d_ino = h2fs32(ip->i_number); 923 if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 && 924 (ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) { 925 ep->e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode)); 926 } else { 927 ep->e2d_type = 0; 928 } 929 error = VOP_BWRITE(bp->b_vp, bp); 930 dp->i_flag |= IN_CHANGE | IN_UPDATE; 931 return (error); 932} 933 934/* 935 * Check if a directory is empty or not. 936 * Inode supplied must be locked. 937 * 938 * Using a struct dirtemplate here is not precisely 939 * what we want, but better than using a struct ext2fs_direct. 940 * 941 * NB: does not handle corrupted directories. 942 */ 943int 944ext2fs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred) 945{ 946 off_t off; 947 struct ext2fs_dirtemplate dbuf; 948 struct ext2fs_direct *dp = (struct ext2fs_direct *)&dbuf; 949 int error, namlen; 950 size_t count; 951 952#define MINDIRSIZ (sizeof (struct ext2fs_dirtemplate) / 2) 953 954 for (off = 0; off < ext2fs_size(ip); off += fs2h16(dp->e2d_reclen)) { 955 error = ufs_bufio(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ, 956 off, IO_NODELOCKED, cred, &count, NULL); 957 /* 958 * Since we read MINDIRSIZ, residual must 959 * be 0 unless we're at end of file. 960 */ 961 if (error || count != 0) 962 return (0); 963 /* avoid infinite loops */ 964 if (dp->e2d_reclen == 0) 965 return (0); 966 /* skip empty entries */ 967 if (dp->e2d_ino == 0) 968 continue; 969 /* accept only "." and ".." */ 970 namlen = dp->e2d_namlen; 971 if (namlen > 2) 972 return (0); 973 if (dp->e2d_name[0] != '.') 974 return (0); 975 /* 976 * At this point namlen must be 1 or 2. 977 * 1 implies ".", 2 implies ".." if second 978 * char is also "." 979 */ 980 if (namlen == 1) 981 continue; 982 if (dp->e2d_name[1] == '.' && fs2h32(dp->e2d_ino) == parentino) 983 continue; 984 return (0); 985 } 986 return (1); 987} 988