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sys/fs/ext2fs/ext2_lookup.c
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1 /*- 2 * modified for Lites 1.1 3 * 4 * Aug 1995, Godmar Back (gback@cs.utah.edu) 5 * University of Utah, Department of Computer Science 6 */ 7 /*- 8 * 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: releng/9.1/sys/fs/ext2fs/ext2_lookup.c 235820 2012-05-23 02:43:28Z 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 DIAGNOSTIC 66 static int dirchk = 1; 67 #else 68 static int dirchk = 0; 69 #endif 70 71 static SYSCTL_NODE(_vfs, OID_AUTO, e2fs, CTLFLAG_RD, 0, "EXT2FS filesystem"); 72 SYSCTL_INT(_vfs_e2fs, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, ""); 73 74 /* 75 DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512) 76 while it is the native blocksize in ext2fs - thus, a #define 77 is no longer appropriate 78 */ 79 #undef DIRBLKSIZ 80 81 static u_char ext2_ft_to_dt[] = { 82 DT_UNKNOWN, /* EXT2_FT_UNKNOWN */ 83 DT_REG, /* EXT2_FT_REG_FILE */ 84 DT_DIR, /* EXT2_FT_DIR */ 85 DT_CHR, /* EXT2_FT_CHRDEV */ 86 DT_BLK, /* EXT2_FT_BLKDEV */ 87 DT_FIFO, /* EXT2_FT_FIFO */ 88 DT_SOCK, /* EXT2_FT_SOCK */ 89 DT_LNK, /* EXT2_FT_SYMLINK */ 90 }; 91 #define FTTODT(ft) \ 92 ((ft) > sizeof(ext2_ft_to_dt) / sizeof(ext2_ft_to_dt[0]) ? \ 93 DT_UNKNOWN : ext2_ft_to_dt[(ft)]) 94 95 static u_char dt_to_ext2_ft[] = { 96 EXT2_FT_UNKNOWN, /* DT_UNKNOWN */ 97 EXT2_FT_FIFO, /* DT_FIFO */ 98 EXT2_FT_CHRDEV, /* DT_CHR */ 99 EXT2_FT_UNKNOWN, /* unused */ 100 EXT2_FT_DIR, /* DT_DIR */ 101 EXT2_FT_UNKNOWN, /* unused */ 102 EXT2_FT_BLKDEV, /* DT_BLK */ 103 EXT2_FT_UNKNOWN, /* unused */ 104 EXT2_FT_REG_FILE, /* DT_REG */ 105 EXT2_FT_UNKNOWN, /* unused */ 106 EXT2_FT_SYMLINK, /* DT_LNK */ 107 EXT2_FT_UNKNOWN, /* unused */ 108 EXT2_FT_SOCK, /* DT_SOCK */ 109 EXT2_FT_UNKNOWN, /* unused */ 110 EXT2_FT_UNKNOWN, /* DT_WHT */ 111 }; 112 #define DTTOFT(dt) \ 113 ((dt) > sizeof(dt_to_ext2_ft) / sizeof(dt_to_ext2_ft[0]) ? \ 114 EXT2_FT_UNKNOWN : dt_to_ext2_ft[(dt)]) 115 116 static int ext2_dirbadentry(struct vnode *dp, struct ext2fs_direct_2 *de, 117 int entryoffsetinblock); 118 static int ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, 119 struct componentname *cnp, ino_t *dd_ino); 120 121 /* 122 * Vnode op for reading directories. 123 * 124 * This function has to convert directory entries from the on-disk 125 * format to the format defined by <sys/dirent.h>. Unfortunately, the 126 * conversion will blow up some entries by four bytes, so it can't be 127 * done in place. Instead, the conversion is done entry by entry and 128 * the converted entry is sent via uiomove. 129 * 130 * XXX allocate a buffer, convert as many entries as possible, then send 131 * the whole buffer to uiomove 132 */ 133 int 134 ext2_readdir(ap) 135 struct vop_readdir_args /* { 136 struct vnode *a_vp; 137 struct uio *a_uio; 138 struct ucred *a_cred; 139 } */ *ap; 140 { 141 struct uio *uio = ap->a_uio; 142 int count, error; 143 144 struct ext2fs_direct_2 *edp, *dp; 145 int ncookies; 146 struct dirent dstdp; 147 struct uio auio; 148 struct iovec aiov; 149 caddr_t dirbuf; 150 int DIRBLKSIZ = VTOI(ap->a_vp)->i_e2fs->e2fs_bsize; 151 int readcnt; 152 off_t startoffset = uio->uio_offset; 153 154 count = uio->uio_resid; 155 /* 156 * Avoid complications for partial directory entries by adjusting 157 * the i/o to end at a block boundary. Don't give up (like ufs 158 * does) if the initial adjustment gives a negative count, since 159 * many callers don't supply a large enough buffer. The correct 160 * size is a little larger than DIRBLKSIZ to allow for expansion 161 * of directory entries, but some callers just use 512. 162 */ 163 count -= (uio->uio_offset + count) & (DIRBLKSIZ -1); 164 if (count <= 0) 165 count += DIRBLKSIZ; 166 auio = *uio; 167 auio.uio_iov = &aiov; 168 auio.uio_iovcnt = 1; 169 auio.uio_resid = count; 170 auio.uio_segflg = UIO_SYSSPACE; 171 aiov.iov_len = count; 172 dirbuf = malloc(count, M_TEMP, M_WAITOK); 173 aiov.iov_base = dirbuf; 174 error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred); 175 if (error == 0) { 176 readcnt = count - auio.uio_resid; 177 edp = (struct ext2fs_direct_2 *)&dirbuf[readcnt]; 178 ncookies = 0; 179 bzero(&dstdp, offsetof(struct dirent, d_name)); 180 for (dp = (struct ext2fs_direct_2 *)dirbuf; 181 !error && uio->uio_resid > 0 && dp < edp; ) { 182 /*- 183 * "New" ext2fs directory entries differ in 3 ways 184 * from ufs on-disk ones: 185 * - the name is not necessarily NUL-terminated. 186 * - the file type field always exists and always 187 * follows the name length field. 188 * - the file type is encoded in a different way. 189 * 190 * "Old" ext2fs directory entries need no special 191 * conversions, since they are binary compatible 192 * with "new" entries having a file type of 0 (i.e., 193 * EXT2_FT_UNKNOWN). Splitting the old name length 194 * field didn't make a mess like it did in ufs, 195 * because ext2fs uses a machine-independent disk 196 * layout. 197 */ 198 dstdp.d_fileno = dp->e2d_ino; 199 dstdp.d_type = FTTODT(dp->e2d_type); 200 dstdp.d_namlen = dp->e2d_namlen; 201 dstdp.d_reclen = GENERIC_DIRSIZ(&dstdp); 202 bcopy(dp->e2d_name, dstdp.d_name, dstdp.d_namlen); 203 bzero(dstdp.d_name + dstdp.d_namlen, 204 dstdp.d_reclen - offsetof(struct dirent, d_name) - 205 dstdp.d_namlen); 206 207 if (dp->e2d_reclen > 0) { 208 if(dstdp.d_reclen <= uio->uio_resid) { 209 /* advance dp */ 210 dp = (struct ext2fs_direct_2 *) 211 ((char *)dp + dp->e2d_reclen); 212 error = 213 uiomove(&dstdp, dstdp.d_reclen, uio); 214 if (!error) 215 ncookies++; 216 } else 217 break; 218 } else { 219 error = EIO; 220 break; 221 } 222 } 223 /* we need to correct uio_offset */ 224 uio->uio_offset = startoffset + (caddr_t)dp - dirbuf; 225 226 if (!error && ap->a_ncookies != NULL) { 227 u_long *cookiep, *cookies, *ecookies; 228 off_t off; 229 230 if (uio->uio_segflg != UIO_SYSSPACE || uio->uio_iovcnt != 1) 231 panic("ext2_readdir: unexpected uio from NFS server"); 232 cookies = malloc(ncookies * sizeof(u_long), M_TEMP, 233 M_WAITOK); 234 off = startoffset; 235 for (dp = (struct ext2fs_direct_2 *)dirbuf, 236 cookiep = cookies, ecookies = cookies + ncookies; 237 cookiep < ecookies; 238 dp = (struct ext2fs_direct_2 *)((caddr_t) dp + dp->e2d_reclen)) { 239 off += dp->e2d_reclen; 240 *cookiep++ = (u_long) off; 241 } 242 *ap->a_ncookies = ncookies; 243 *ap->a_cookies = cookies; 244 } 245 } 246 free(dirbuf, M_TEMP); 247 if (ap->a_eofflag) 248 *ap->a_eofflag = VTOI(ap->a_vp)->i_size <= uio->uio_offset; 249 return (error); 250 } 251 252 /* 253 * Convert a component of a pathname into a pointer to a locked inode. 254 * This is a very central and rather complicated routine. 255 * If the file system is not maintained in a strict tree hierarchy, 256 * this can result in a deadlock situation (see comments in code below). 257 * 258 * The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending 259 * on whether the name is to be looked up, created, renamed, or deleted. 260 * When CREATE, RENAME, or DELETE is specified, information usable in 261 * creating, renaming, or deleting a directory entry may be calculated. 262 * If flag has LOCKPARENT or'ed into it and the target of the pathname 263 * exists, lookup returns both the target and its parent directory locked. 264 * When creating or renaming and LOCKPARENT is specified, the target may 265 * not be ".". When deleting and LOCKPARENT is specified, the target may 266 * be "."., but the caller must check to ensure it does an vrele and vput 267 * instead of two vputs. 268 * 269 * Overall outline of ext2_lookup: 270 * 271 * search for name in directory, to found or notfound 272 * notfound: 273 * if creating, return locked directory, leaving info on available slots 274 * else return error 275 * found: 276 * if at end of path and deleting, return information to allow delete 277 * if at end of path and rewriting (RENAME and LOCKPARENT), lock target 278 * inode and return info to allow rewrite 279 * if not at end, add name to cache; if at end and neither creating 280 * nor deleting, add name to cache 281 */ 282 int 283 ext2_lookup(ap) 284 struct vop_cachedlookup_args /* { 285 struct vnode *a_dvp; 286 struct vnode **a_vpp; 287 struct componentname *a_cnp; 288 } */ *ap; 289 { 290 291 return (ext2_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); 292 } 293 294 static int 295 ext2_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp, 296 ino_t *dd_ino) 297 { 298 struct inode *dp; /* inode for directory being searched */ 299 struct buf *bp; /* a buffer of directory entries */ 300 struct ext2fs_direct_2 *ep; /* the current directory entry */ 301 int entryoffsetinblock; /* offset of ep in bp's buffer */ 302 enum {NONE, COMPACT, FOUND} slotstatus; 303 doff_t slotoffset; /* offset of area with free space */ 304 int slotsize; /* size of area at slotoffset */ 305 doff_t i_diroff; /* cached i_diroff value */ 306 doff_t i_offset; /* cached i_offset value */ 307 int slotfreespace; /* amount of space free in slot */ 308 int slotneeded; /* size of the entry we're seeking */ 309 int numdirpasses; /* strategy for directory search */ 310 doff_t endsearch; /* offset to end directory search */ 311 doff_t prevoff; /* prev entry dp->i_offset */ 312 struct vnode *pdp; /* saved dp during symlink work */ 313 struct vnode *tdp; /* returned by VFS_VGET */ 314 doff_t enduseful; /* pointer past last used dir slot */ 315 u_long bmask; /* block offset mask */ 316 int namlen, error; 317 struct ucred *cred = cnp->cn_cred; 318 int flags = cnp->cn_flags; 319 int nameiop = cnp->cn_nameiop; 320 ino_t ino, ino1; 321 int ltype; 322 323 int DIRBLKSIZ = VTOI(vdp)->i_e2fs->e2fs_bsize; 324 325 if (vpp != NULL) 326 *vpp = NULL; 327 328 dp = VTOI(vdp); 329 bmask = VFSTOEXT2(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 330 restart: 331 bp = NULL; 332 slotoffset = -1; 333 334 /* 335 * We now have a segment name to search for, and a directory to search. 336 */ 337 338 /* 339 * Suppress search for slots unless creating 340 * file and at end of pathname, in which case 341 * we watch for a place to put the new file in 342 * case it doesn't already exist. 343 */ 344 ino = 0; 345 i_diroff = dp->i_diroff; 346 slotstatus = FOUND; 347 slotfreespace = slotsize = slotneeded = 0; 348 if ((nameiop == CREATE || nameiop == RENAME) && 349 (flags & ISLASTCN)) { 350 slotstatus = NONE; 351 slotneeded = EXT2_DIR_REC_LEN(cnp->cn_namelen); 352 /* was 353 slotneeded = (sizeof(struct direct) - MAXNAMLEN + 354 cnp->cn_namelen + 3) &~ 3; */ 355 } 356 357 /* 358 * If there is cached information on a previous search of 359 * this directory, pick up where we last left off. 360 * We cache only lookups as these are the most common 361 * and have the greatest payoff. Caching CREATE has little 362 * benefit as it usually must search the entire directory 363 * to determine that the entry does not exist. Caching the 364 * location of the last DELETE or RENAME has not reduced 365 * profiling time and hence has been removed in the interest 366 * of simplicity. 367 */ 368 if (nameiop != LOOKUP || i_diroff == 0 || 369 i_diroff > dp->i_size) { 370 entryoffsetinblock = 0; 371 i_offset = 0; 372 numdirpasses = 1; 373 } else { 374 i_offset = i_diroff; 375 if ((entryoffsetinblock = i_offset & bmask) && 376 (error = ext2_blkatoff(vdp, (off_t)i_offset, NULL, 377 &bp))) 378 return (error); 379 numdirpasses = 2; 380 nchstats.ncs_2passes++; 381 } 382 prevoff = i_offset; 383 endsearch = roundup2(dp->i_size, DIRBLKSIZ); 384 enduseful = 0; 385 386 searchloop: 387 while (i_offset < endsearch) { 388 /* 389 * If necessary, get the next directory block. 390 */ 391 if ((i_offset & bmask) == 0) { 392 if (bp != NULL) 393 brelse(bp); 394 if ((error = 395 ext2_blkatoff(vdp, (off_t)i_offset, NULL, 396 &bp)) != 0) 397 return (error); 398 entryoffsetinblock = 0; 399 } 400 /* 401 * If still looking for a slot, and at a DIRBLKSIZE 402 * boundary, have to start looking for free space again. 403 */ 404 if (slotstatus == NONE && 405 (entryoffsetinblock & (DIRBLKSIZ - 1)) == 0) { 406 slotoffset = -1; 407 slotfreespace = 0; 408 } 409 /* 410 * Get pointer to next entry. 411 * Full validation checks are slow, so we only check 412 * enough to insure forward progress through the 413 * directory. Complete checks can be run by setting 414 * "vfs.e2fs.dirchk" to be true. 415 */ 416 ep = (struct ext2fs_direct_2 *) 417 ((char *)bp->b_data + entryoffsetinblock); 418 if (ep->e2d_reclen == 0 || 419 (dirchk && ext2_dirbadentry(vdp, ep, entryoffsetinblock))) { 420 int i; 421 ext2_dirbad(dp, i_offset, "mangled entry"); 422 i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)); 423 i_offset += i; 424 entryoffsetinblock += i; 425 continue; 426 } 427 428 /* 429 * If an appropriate sized slot has not yet been found, 430 * check to see if one is available. Also accumulate space 431 * in the current block so that we can determine if 432 * compaction is viable. 433 */ 434 if (slotstatus != FOUND) { 435 int size = ep->e2d_reclen; 436 437 if (ep->e2d_ino != 0) 438 size -= EXT2_DIR_REC_LEN(ep->e2d_namlen); 439 if (size > 0) { 440 if (size >= slotneeded) { 441 slotstatus = FOUND; 442 slotoffset = i_offset; 443 slotsize = ep->e2d_reclen; 444 } else if (slotstatus == NONE) { 445 slotfreespace += size; 446 if (slotoffset == -1) 447 slotoffset = i_offset; 448 if (slotfreespace >= slotneeded) { 449 slotstatus = COMPACT; 450 slotsize = i_offset + 451 ep->e2d_reclen - slotoffset; 452 } 453 } 454 } 455 } 456 457 /* 458 * Check for a name match. 459 */ 460 if (ep->e2d_ino) { 461 namlen = ep->e2d_namlen; 462 if (namlen == cnp->cn_namelen && 463 !bcmp(cnp->cn_nameptr, ep->e2d_name, 464 (unsigned)namlen)) { 465 /* 466 * Save directory entry's inode number and 467 * reclen in ndp->ni_ufs area, and release 468 * directory buffer. 469 */ 470 ino = ep->e2d_ino; 471 goto found; 472 } 473 } 474 prevoff = i_offset; 475 i_offset += ep->e2d_reclen; 476 entryoffsetinblock += ep->e2d_reclen; 477 if (ep->e2d_ino) 478 enduseful = i_offset; 479 } 480 /* notfound: */ 481 /* 482 * If we started in the middle of the directory and failed 483 * to find our target, we must check the beginning as well. 484 */ 485 if (numdirpasses == 2) { 486 numdirpasses--; 487 i_offset = 0; 488 endsearch = i_diroff; 489 goto searchloop; 490 } 491 dp->i_offset = i_offset; 492 if (bp != NULL) 493 brelse(bp); 494 /* 495 * If creating, and at end of pathname and current 496 * directory has not been removed, then can consider 497 * allowing file to be created. 498 */ 499 if ((nameiop == CREATE || nameiop == RENAME) && 500 (flags & ISLASTCN) && dp->i_nlink != 0) { 501 /* 502 * Access for write is interpreted as allowing 503 * creation of files in the directory. 504 */ 505 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 506 return (error); 507 /* 508 * Return an indication of where the new directory 509 * entry should be put. If we didn't find a slot, 510 * then set dp->i_count to 0 indicating 511 * that the new slot belongs at the end of the 512 * directory. If we found a slot, then the new entry 513 * can be put in the range from dp->i_offset to 514 * dp->i_offset + dp->i_count. 515 */ 516 if (slotstatus == NONE) { 517 dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ); 518 dp->i_count = 0; 519 enduseful = dp->i_offset; 520 } else { 521 dp->i_offset = slotoffset; 522 dp->i_count = slotsize; 523 if (enduseful < slotoffset + slotsize) 524 enduseful = slotoffset + slotsize; 525 } 526 dp->i_endoff = roundup2(enduseful, DIRBLKSIZ); 527 dp->i_flag |= IN_CHANGE | IN_UPDATE; 528 /* 529 * We return with the directory locked, so that 530 * the parameters we set up above will still be 531 * valid if we actually decide to do a direnter(). 532 * We return ni_vp == NULL to indicate that the entry 533 * does not currently exist; we leave a pointer to 534 * the (locked) directory inode in ndp->ni_dvp. 535 * The pathname buffer is saved so that the name 536 * can be obtained later. 537 * 538 * NB - if the directory is unlocked, then this 539 * information cannot be used. 540 */ 541 cnp->cn_flags |= SAVENAME; 542 return (EJUSTRETURN); 543 } 544 /* 545 * Insert name into cache (as non-existent) if appropriate. 546 */ 547 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 548 cache_enter(vdp, NULL, cnp); 549 return (ENOENT); 550 551 found: 552 if (dd_ino != NULL) 553 *dd_ino = ino; 554 if (numdirpasses == 2) 555 nchstats.ncs_pass2++; 556 /* 557 * Check that directory length properly reflects presence 558 * of this entry. 559 */ 560 if (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->e2d_namlen) 561 > dp->i_size) { 562 ext2_dirbad(dp, i_offset, "i_size too small"); 563 dp->i_size = entryoffsetinblock+EXT2_DIR_REC_LEN(ep->e2d_namlen); 564 dp->i_flag |= IN_CHANGE | IN_UPDATE; 565 } 566 brelse(bp); 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 dp->i_diroff = i_offset &~ (DIRBLKSIZ - 1); 575 dp->i_offset = i_offset; 576 /* 577 * If deleting, and at end of pathname, return 578 * parameters which can be used to remove file. 579 */ 580 if (nameiop == DELETE && (flags & ISLASTCN)) { 581 /* 582 * Write access to directory required to delete files. 583 */ 584 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 585 return (error); 586 /* 587 * Return pointer to current entry in dp->i_offset, 588 * and distance past previous entry (if there 589 * is a previous entry in this block) in dp->i_count. 590 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 591 */ 592 if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0) 593 dp->i_count = 0; 594 else 595 dp->i_count = dp->i_offset - prevoff; 596 if (dd_ino != NULL) 597 return (0); 598 if (dp->i_number == ino) { 599 VREF(vdp); 600 *vpp = vdp; 601 return (0); 602 } 603 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 604 &tdp)) != 0) 605 return (error); 606 /* 607 * If directory is "sticky", then user must own 608 * the directory, or the file in it, else she 609 * may not delete it (unless she's root). This 610 * implements append-only directories. 611 */ 612 if ((dp->i_mode & ISVTX) && 613 cred->cr_uid != 0 && 614 cred->cr_uid != dp->i_uid && 615 VTOI(tdp)->i_uid != cred->cr_uid) { 616 vput(tdp); 617 return (EPERM); 618 } 619 *vpp = tdp; 620 return (0); 621 } 622 623 /* 624 * If rewriting (RENAME), return the inode and the 625 * information required to rewrite the present directory 626 * Must get inode of directory entry to verify it's a 627 * regular file, or empty directory. 628 */ 629 if (nameiop == RENAME && (flags & ISLASTCN)) { 630 if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0) 631 return (error); 632 /* 633 * Careful about locking second inode. 634 * This can only occur if the target is ".". 635 */ 636 if (dp->i_number == ino) 637 return (EISDIR); 638 if (dd_ino != NULL) 639 return (0); 640 if ((error = VFS_VGET(vdp->v_mount, ino, LK_EXCLUSIVE, 641 &tdp)) != 0) 642 return (error); 643 *vpp = tdp; 644 cnp->cn_flags |= SAVENAME; 645 return (0); 646 } 647 if (dd_ino != NULL) 648 return (0); 649 650 /* 651 * Step through the translation in the name. We do not `vput' the 652 * directory because we may need it again if a symbolic link 653 * is relative to the current directory. Instead we save it 654 * unlocked as "pdp". We must get the target inode before unlocking 655 * the directory to insure that the inode will not be removed 656 * before we get it. We prevent deadlock by always fetching 657 * inodes from the root, moving down the directory tree. Thus 658 * when following backward pointers ".." we must unlock the 659 * parent directory before getting the requested directory. 660 * There is a potential race condition here if both the current 661 * and parent directories are removed before the VFS_VGET for the 662 * inode associated with ".." returns. We hope that this occurs 663 * infrequently since we cannot avoid this race condition without 664 * implementing a sophisticated deadlock detection algorithm. 665 * Note also that this simple deadlock detection scheme will not 666 * work if the file system has any hard links other than ".." 667 * that point backwards in the directory structure. 668 */ 669 pdp = vdp; 670 if (flags & ISDOTDOT) { 671 ltype = VOP_ISLOCKED(pdp); 672 VOP_UNLOCK(pdp, 0); /* race to get the inode */ 673 error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags, &tdp); 674 vn_lock(pdp, ltype | LK_RETRY); 675 if (pdp->v_iflag & VI_DOOMED) { 676 if (error == 0) 677 vput(tdp); 678 error = ENOENT; 679 } 680 if (error) 681 return (error); 682 /* 683 * Recheck that ".." entry in the vdp directory points 684 * to the inode we looked up before vdp lock was 685 * dropped. 686 */ 687 error = ext2_lookup_ino(pdp, NULL, cnp, &ino1); 688 if (error) { 689 vput(tdp); 690 return (error); 691 } 692 if (ino1 != ino) { 693 vput(tdp); 694 goto restart; 695 } 696 *vpp = tdp; 697 } else if (dp->i_number == ino) { 698 VREF(vdp); /* we want ourself, ie "." */ 699 /* 700 * When we lookup "." we still can be asked to lock it 701 * differently. 702 */ 703 ltype = cnp->cn_lkflags & LK_TYPE_MASK; 704 if (ltype != VOP_ISLOCKED(vdp)) { 705 if (ltype == LK_EXCLUSIVE) 706 vn_lock(vdp, LK_UPGRADE | LK_RETRY); 707 else /* if (ltype == LK_SHARED) */ 708 vn_lock(vdp, LK_DOWNGRADE | LK_RETRY); 709 } 710 *vpp = vdp; 711 } else { 712 if ((error = VFS_VGET(vdp->v_mount, ino, cnp->cn_lkflags, 713 &tdp)) != 0) 714 return (error); 715 *vpp = tdp; 716 } 717 718 /* 719 * Insert name into cache if appropriate. 720 */ 721 if (cnp->cn_flags & MAKEENTRY) 722 cache_enter(vdp, *vpp, cnp); 723 return (0); 724 } 725 726 void 727 ext2_dirbad(ip, offset, how) 728 struct inode *ip; 729 doff_t offset; 730 char *how; 731 { 732 struct mount *mp; 733 734 mp = ITOV(ip)->v_mount; 735 if ((mp->mnt_flag & MNT_RDONLY) == 0) 736 panic("ext2_dirbad: %s: bad dir ino %lu at offset %ld: %s\n", 737 mp->mnt_stat.f_mntonname, (u_long)ip->i_number,(long)offset, how); 738 else 739 (void)printf("%s: bad dir ino %lu at offset %ld: %s\n", 740 mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how); 741 742 } 743 744 /* 745 * Do consistency checking on a directory entry: 746 * record length must be multiple of 4 747 * entry must fit in rest of its DIRBLKSIZ block 748 * record must be large enough to contain entry 749 * name is not longer than MAXNAMLEN 750 * name must be as long as advertised, and null terminated 751 */ 752 /* 753 * changed so that it confirms to ext2_check_dir_entry 754 */ 755 static int 756 ext2_dirbadentry(dp, de, entryoffsetinblock) 757 struct vnode *dp; 758 struct ext2fs_direct_2 *de; 759 int entryoffsetinblock; 760 { 761 int DIRBLKSIZ = VTOI(dp)->i_e2fs->e2fs_bsize; 762 763 char * error_msg = NULL; 764 765 if (de->e2d_reclen < EXT2_DIR_REC_LEN(1)) 766 error_msg = "rec_len is smaller than minimal"; 767 else if (de->e2d_reclen % 4 != 0) 768 error_msg = "rec_len % 4 != 0"; 769 else if (de->e2d_reclen < EXT2_DIR_REC_LEN(de->e2d_namlen)) 770 error_msg = "reclen is too small for name_len"; 771 else if (entryoffsetinblock + de->e2d_reclen > DIRBLKSIZ) 772 error_msg = "directory entry across blocks"; 773 /* else LATER 774 if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count) 775 error_msg = "inode out of bounds"; 776 */ 777 778 if (error_msg != NULL) { 779 printf("bad directory entry: %s\n", error_msg); 780 printf("offset=%d, inode=%lu, rec_len=%u, name_len=%u\n", 781 entryoffsetinblock, (unsigned long)de->e2d_ino, 782 de->e2d_reclen, de->e2d_namlen); 783 } 784 return error_msg == NULL ? 0 : 1; 785 } 786 787 /* 788 * Write a directory entry after a call to namei, using the parameters 789 * that it left in nameidata. The argument ip is the inode which the new 790 * directory entry will refer to. Dvp is a pointer to the directory to 791 * be written, which was left locked by namei. Remaining parameters 792 * (dp->i_offset, dp->i_count) indicate how the space for the new 793 * entry is to be obtained. 794 */ 795 int 796 ext2_direnter(ip, dvp, cnp) 797 struct inode *ip; 798 struct vnode *dvp; 799 struct componentname *cnp; 800 { 801 struct ext2fs_direct_2 *ep, *nep; 802 struct inode *dp; 803 struct buf *bp; 804 struct ext2fs_direct_2 newdir; 805 struct iovec aiov; 806 struct uio auio; 807 u_int dsize; 808 int error, loc, newentrysize, spacefree; 809 char *dirbuf; 810 int DIRBLKSIZ = ip->i_e2fs->e2fs_bsize; 811 812 813 #ifdef DIAGNOSTIC 814 if ((cnp->cn_flags & SAVENAME) == 0) 815 panic("direnter: missing name"); 816 #endif 817 dp = VTOI(dvp); 818 newdir.e2d_ino = ip->i_number; 819 newdir.e2d_namlen = cnp->cn_namelen; 820 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 821 EXT2F_INCOMPAT_FTYPE)) 822 newdir.e2d_type = DTTOFT(IFTODT(ip->i_mode)); 823 else 824 newdir.e2d_type = EXT2_FT_UNKNOWN; 825 bcopy(cnp->cn_nameptr, newdir.e2d_name, (unsigned)cnp->cn_namelen + 1); 826 newentrysize = EXT2_DIR_REC_LEN(newdir.e2d_namlen); 827 if (dp->i_count == 0) { 828 /* 829 * If dp->i_count is 0, then namei could find no 830 * space in the directory. Here, dp->i_offset will 831 * be on a directory block boundary and we will write the 832 * new entry into a fresh block. 833 */ 834 if (dp->i_offset & (DIRBLKSIZ - 1)) 835 panic("ext2_direnter: newblk"); 836 auio.uio_offset = dp->i_offset; 837 newdir.e2d_reclen = DIRBLKSIZ; 838 auio.uio_resid = newentrysize; 839 aiov.iov_len = newentrysize; 840 aiov.iov_base = (caddr_t)&newdir; 841 auio.uio_iov = &aiov; 842 auio.uio_iovcnt = 1; 843 auio.uio_rw = UIO_WRITE; 844 auio.uio_segflg = UIO_SYSSPACE; 845 auio.uio_td = (struct thread *)0; 846 error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred); 847 if (DIRBLKSIZ > 848 VFSTOEXT2(dvp->v_mount)->um_mountp->mnt_stat.f_bsize) 849 /* XXX should grow with balloc() */ 850 panic("ext2_direnter: frag size"); 851 else if (!error) { 852 dp->i_size = roundup2(dp->i_size, DIRBLKSIZ); 853 dp->i_flag |= IN_CHANGE; 854 } 855 return (error); 856 } 857 858 /* 859 * If dp->i_count is non-zero, then namei found space 860 * for the new entry in the range dp->i_offset to 861 * dp->i_offset + dp->i_count in the directory. 862 * To use this space, we may have to compact the entries located 863 * there, by copying them together towards the beginning of the 864 * block, leaving the free space in one usable chunk at the end. 865 */ 866 867 /* 868 * Increase size of directory if entry eats into new space. 869 * This should never push the size past a new multiple of 870 * DIRBLKSIZE. 871 * 872 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN. 873 */ 874 if (dp->i_offset + dp->i_count > dp->i_size) 875 dp->i_size = dp->i_offset + dp->i_count; 876 /* 877 * Get the block containing the space for the new directory entry. 878 */ 879 if ((error = ext2_blkatoff(dvp, (off_t)dp->i_offset, &dirbuf, 880 &bp)) != 0) 881 return (error); 882 /* 883 * Find space for the new entry. In the simple case, the entry at 884 * offset base will have the space. If it does not, then namei 885 * arranged that compacting the region dp->i_offset to 886 * dp->i_offset + dp->i_count would yield the 887 * space. 888 */ 889 ep = (struct ext2fs_direct_2 *)dirbuf; 890 dsize = EXT2_DIR_REC_LEN(ep->e2d_namlen); 891 spacefree = ep->e2d_reclen - dsize; 892 for (loc = ep->e2d_reclen; loc < dp->i_count; ) { 893 nep = (struct ext2fs_direct_2 *)(dirbuf + loc); 894 if (ep->e2d_ino) { 895 /* trim the existing slot */ 896 ep->e2d_reclen = dsize; 897 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 898 } else { 899 /* overwrite; nothing there; header is ours */ 900 spacefree += dsize; 901 } 902 dsize = EXT2_DIR_REC_LEN(nep->e2d_namlen); 903 spacefree += nep->e2d_reclen - dsize; 904 loc += nep->e2d_reclen; 905 bcopy((caddr_t)nep, (caddr_t)ep, dsize); 906 } 907 /* 908 * Update the pointer fields in the previous entry (if any), 909 * copy in the new entry, and write out the block. 910 */ 911 if (ep->e2d_ino == 0) { 912 if (spacefree + dsize < newentrysize) 913 panic("ext2_direnter: compact1"); 914 newdir.e2d_reclen = spacefree + dsize; 915 } else { 916 if (spacefree < newentrysize) 917 panic("ext2_direnter: compact2"); 918 newdir.e2d_reclen = spacefree; 919 ep->e2d_reclen = dsize; 920 ep = (struct ext2fs_direct_2 *)((char *)ep + dsize); 921 } 922 bcopy((caddr_t)&newdir, (caddr_t)ep, (u_int)newentrysize); 923 if (DOINGASYNC(dvp)) { 924 bdwrite(bp); 925 error = 0; 926 } else { 927 error = bwrite(bp); 928 } 929 dp->i_flag |= IN_CHANGE | IN_UPDATE; 930 if (!error && dp->i_endoff && dp->i_endoff < dp->i_size) 931 error = ext2_truncate(dvp, (off_t)dp->i_endoff, IO_SYNC, 932 cnp->cn_cred, cnp->cn_thread); 933 return (error); 934 } 935 936 /* 937 * Remove a directory entry after a call to namei, using 938 * the parameters which it left in nameidata. The entry 939 * dp->i_offset contains the offset into the directory of the 940 * entry to be eliminated. The dp->i_count field contains the 941 * size of the previous record in the directory. If this 942 * is 0, the first entry is being deleted, so we need only 943 * zero the inode number to mark the entry as free. If the 944 * entry is not the first in the directory, we must reclaim 945 * the space of the now empty record by adding the record size 946 * to the size of the previous entry. 947 */ 948 int 949 ext2_dirremove(dvp, cnp) 950 struct vnode *dvp; 951 struct componentname *cnp; 952 { 953 struct inode *dp; 954 struct ext2fs_direct_2 *ep, *rep; 955 struct buf *bp; 956 int error; 957 958 dp = VTOI(dvp); 959 if (dp->i_count == 0) { 960 /* 961 * First entry in block: set d_ino to zero. 962 */ 963 if ((error = 964 ext2_blkatoff(dvp, (off_t)dp->i_offset, (char **)&ep, 965 &bp)) != 0) 966 return (error); 967 ep->e2d_ino = 0; 968 error = bwrite(bp); 969 dp->i_flag |= IN_CHANGE | IN_UPDATE; 970 return (error); 971 } 972 /* 973 * Collapse new free space into previous entry. 974 */ 975 if ((error = ext2_blkatoff(dvp, (off_t)(dp->i_offset - dp->i_count), 976 (char **)&ep, &bp)) != 0) 977 return (error); 978 979 /* Set 'rep' to the entry being removed. */ 980 if (dp->i_count == 0) 981 rep = ep; 982 else 983 rep = (struct ext2fs_direct_2 *)((char *)ep + ep->e2d_reclen); 984 ep->e2d_reclen += rep->e2d_reclen; 985 if (DOINGASYNC(dvp) && dp->i_count != 0) 986 bdwrite(bp); 987 else 988 error = bwrite(bp); 989 dp->i_flag |= IN_CHANGE | IN_UPDATE; 990 return (error); 991 } 992 993 /* 994 * Rewrite an existing directory entry to point at the inode 995 * supplied. The parameters describing the directory entry are 996 * set up by a call to namei. 997 */ 998 int 999 ext2_dirrewrite(dp, ip, cnp) 1000 struct inode *dp, *ip; 1001 struct componentname *cnp; 1002 { 1003 struct buf *bp; 1004 struct ext2fs_direct_2 *ep; 1005 struct vnode *vdp = ITOV(dp); 1006 int error; 1007 1008 if ((error = ext2_blkatoff(vdp, (off_t)dp->i_offset, (char **)&ep, 1009 &bp)) != 0) 1010 return (error); 1011 ep->e2d_ino = ip->i_number; 1012 if (EXT2_HAS_INCOMPAT_FEATURE(ip->i_e2fs, 1013 EXT2F_INCOMPAT_FTYPE)) 1014 ep->e2d_type = DTTOFT(IFTODT(ip->i_mode)); 1015 else 1016 ep->e2d_type = EXT2_FT_UNKNOWN; 1017 error = bwrite(bp); 1018 dp->i_flag |= IN_CHANGE | IN_UPDATE; 1019 return (error); 1020 } 1021 1022 /* 1023 * Check if a directory is empty or not. 1024 * Inode supplied must be locked. 1025 * 1026 * Using a struct dirtemplate here is not precisely 1027 * what we want, but better than using a struct direct. 1028 * 1029 * NB: does not handle corrupted directories. 1030 */ 1031 int 1032 ext2_dirempty(ip, parentino, cred) 1033 struct inode *ip; 1034 ino_t parentino; 1035 struct ucred *cred; 1036 { 1037 off_t off; 1038 struct dirtemplate dbuf; 1039 struct ext2fs_direct_2 *dp = (struct ext2fs_direct_2 *)&dbuf; 1040 int error, namlen; 1041 ssize_t count; 1042 #define MINDIRSIZ (sizeof(struct dirtemplate) / 2) 1043 1044 for (off = 0; off < ip->i_size; off += dp->e2d_reclen) { 1045 error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, 1046 off, UIO_SYSSPACE, IO_NODELOCKED | IO_NOMACCHECK, cred, 1047 NOCRED, &count, (struct thread *)0); 1048 /* 1049 * Since we read MINDIRSIZ, residual must 1050 * be 0 unless we're at end of file. 1051 */ 1052 if (error || count != 0) 1053 return (0); 1054 /* avoid infinite loops */ 1055 if (dp->e2d_reclen == 0) 1056 return (0); 1057 /* skip empty entries */ 1058 if (dp->e2d_ino == 0) 1059 continue; 1060 /* accept only "." and ".." */ 1061 namlen = dp->e2d_namlen; 1062 if (namlen > 2) 1063 return (0); 1064 if (dp->e2d_name[0] != '.') 1065 return (0); 1066 /* 1067 * At this point namlen must be 1 or 2. 1068 * 1 implies ".", 2 implies ".." if second 1069 * char is also "." 1070 */ 1071 if (namlen == 1) 1072 continue; 1073 if (dp->e2d_name[1] == '.' && dp->e2d_ino == parentino) 1074 continue; 1075 return (0); 1076 } 1077 return (1); 1078 } 1079 1080 /* 1081 * Check if source directory is in the path of the target directory. 1082 * Target is supplied locked, source is unlocked. 1083 * The target is always vput before returning. 1084 */ 1085 int 1086 ext2_checkpath(source, target, cred) 1087 struct inode *source, *target; 1088 struct ucred *cred; 1089 { 1090 struct vnode *vp; 1091 int error, rootino, namlen; 1092 struct dirtemplate dirbuf; 1093 1094 vp = ITOV(target); 1095 if (target->i_number == source->i_number) { 1096 error = EEXIST; 1097 goto out; 1098 } 1099 rootino = EXT2_ROOTINO; 1100 error = 0; 1101 if (target->i_number == rootino) 1102 goto out; 1103 1104 for (;;) { 1105 if (vp->v_type != VDIR) { 1106 error = ENOTDIR; 1107 break; 1108 } 1109 error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf, 1110 sizeof(struct dirtemplate), (off_t)0, UIO_SYSSPACE, 1111 IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, 1112 NULL); 1113 if (error != 0) 1114 break; 1115 namlen = dirbuf.dotdot_type; /* like ufs little-endian */ 1116 if (namlen != 2 || 1117 dirbuf.dotdot_name[0] != '.' || 1118 dirbuf.dotdot_name[1] != '.') { 1119 error = ENOTDIR; 1120 break; 1121 } 1122 if (dirbuf.dotdot_ino == source->i_number) { 1123 error = EINVAL; 1124 break; 1125 } 1126 if (dirbuf.dotdot_ino == rootino) 1127 break; 1128 vput(vp); 1129 if ((error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, 1130 LK_EXCLUSIVE, &vp)) != 0) { 1131 vp = NULL; 1132 break; 1133 } 1134 } 1135 1136 out: 1137 if (error == ENOTDIR) 1138 printf("checkpath: .. not a directory\n"); 1139 if (vp != NULL) 1140 vput(vp); 1141 return (error); 1142 }
Cache object: 18965b22eca7a24fbbc0da059f24d4a8
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