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sys/fs/msdosfs/msdosfs_lookup.c
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1 /* $FreeBSD: releng/11.0/sys/fs/msdosfs/msdosfs_lookup.c 298806 2016-04-29 20:51:24Z pfg $ */ 2 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */ 3 4 /*- 5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 7 * All rights reserved. 8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by TooLs GmbH. 21 * 4. The name of TooLs GmbH may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 /*- 36 * Written by Paul Popelka (paulp@uts.amdahl.com) 37 * 38 * You can do anything you want with this software, just don't say you wrote 39 * it, and don't remove this notice. 40 * 41 * This software is provided "as is". 42 * 43 * The author supplies this software to be publicly redistributed on the 44 * understanding that the author is not responsible for the correct 45 * functioning of this software in any circumstances and is not liable for 46 * any damages caused by this software. 47 * 48 * October 1992 49 */ 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/buf.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <sys/vnode.h> 57 58 #include <fs/msdosfs/bpb.h> 59 #include <fs/msdosfs/direntry.h> 60 #include <fs/msdosfs/denode.h> 61 #include <fs/msdosfs/fat.h> 62 #include <fs/msdosfs/msdosfsmount.h> 63 64 static int msdosfs_lookup_(struct vnode *vdp, struct vnode **vpp, 65 struct componentname *cnp, u_int64_t *inum); 66 67 int 68 msdosfs_lookup(struct vop_cachedlookup_args *ap) 69 { 70 71 return (msdosfs_lookup_(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL)); 72 } 73 74 struct deget_dotdot { 75 u_long cluster; 76 int blkoff; 77 }; 78 79 static int 80 msdosfs_deget_dotdot(struct mount *mp, void *arg, int lkflags, 81 struct vnode **rvp) 82 { 83 struct deget_dotdot *dd_arg; 84 struct denode *rdp; 85 struct msdosfsmount *pmp; 86 int error; 87 88 pmp = VFSTOMSDOSFS(mp); 89 dd_arg = arg; 90 error = deget(pmp, dd_arg->cluster, dd_arg->blkoff, &rdp); 91 if (error == 0) 92 *rvp = DETOV(rdp); 93 return (error); 94 } 95 96 /* 97 * When we search a directory the blocks containing directory entries are 98 * read and examined. The directory entries contain information that would 99 * normally be in the inode of a unix filesystem. This means that some of 100 * a directory's contents may also be in memory resident denodes (sort of 101 * an inode). This can cause problems if we are searching while some other 102 * process is modifying a directory. To prevent one process from accessing 103 * incompletely modified directory information we depend upon being the 104 * sole owner of a directory block. bread/brelse provide this service. 105 * This being the case, when a process modifies a directory it must first 106 * acquire the disk block that contains the directory entry to be modified. 107 * Then update the disk block and the denode, and then write the disk block 108 * out to disk. This way disk blocks containing directory entries and in 109 * memory denode's will be in synch. 110 */ 111 static int 112 msdosfs_lookup_(struct vnode *vdp, struct vnode **vpp, 113 struct componentname *cnp, u_int64_t *dd_inum) 114 { 115 struct mbnambuf nb; 116 daddr_t bn; 117 int error; 118 int slotcount; 119 int slotoffset = 0; 120 int frcn; 121 u_long cluster; 122 int blkoff; 123 int diroff; 124 int blsize; 125 int isadir; /* ~0 if found direntry is a directory */ 126 u_long scn; /* starting cluster number */ 127 struct vnode *pdp; 128 struct denode *dp; 129 struct denode *tdp; 130 struct msdosfsmount *pmp; 131 struct buf *bp = NULL; 132 struct direntry *dep = NULL; 133 struct deget_dotdot dd_arg; 134 u_char dosfilename[12]; 135 int flags = cnp->cn_flags; 136 int nameiop = cnp->cn_nameiop; 137 int unlen; 138 u_int64_t inode1; 139 140 int wincnt = 1; 141 int chksum = -1, chksum_ok; 142 int olddos = 1; 143 144 #ifdef MSDOSFS_DEBUG 145 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr); 146 #endif 147 dp = VTODE(vdp); 148 pmp = dp->de_pmp; 149 #ifdef MSDOSFS_DEBUG 150 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n", 151 vdp, dp, dp->de_Attributes); 152 #endif 153 154 restart: 155 if (vpp != NULL) 156 *vpp = NULL; 157 /* 158 * If they are going after the . or .. entry in the root directory, 159 * they won't find it. DOS filesystems don't have them in the root 160 * directory. So, we fake it. deget() is in on this scam too. 161 */ 162 if ((vdp->v_vflag & VV_ROOT) && cnp->cn_nameptr[0] == '.' && 163 (cnp->cn_namelen == 1 || 164 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) { 165 isadir = ATTR_DIRECTORY; 166 scn = MSDOSFSROOT; 167 #ifdef MSDOSFS_DEBUG 168 printf("msdosfs_lookup(): looking for . or .. in root directory\n"); 169 #endif 170 cluster = MSDOSFSROOT; 171 blkoff = MSDOSFSROOT_OFS; 172 goto foundroot; 173 } 174 175 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 176 cnp->cn_namelen, 0, pmp)) { 177 case 0: 178 return (EINVAL); 179 case 1: 180 break; 181 case 2: 182 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 183 cnp->cn_namelen, pmp) + 1; 184 break; 185 case 3: 186 olddos = 0; 187 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 188 cnp->cn_namelen, pmp) + 1; 189 break; 190 } 191 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) { 192 wincnt = 1; 193 olddos = 1; 194 } 195 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen); 196 197 /* 198 * Suppress search for slots unless creating 199 * file and at end of pathname, in which case 200 * we watch for a place to put the new file in 201 * case it doesn't already exist. 202 */ 203 slotcount = wincnt; 204 if ((nameiop == CREATE || nameiop == RENAME) && 205 (flags & ISLASTCN)) 206 slotcount = 0; 207 208 #ifdef MSDOSFS_DEBUG 209 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n", 210 dosfilename, cnp->cn_namelen); 211 #endif 212 /* 213 * Search the directory pointed at by vdp for the name pointed at 214 * by cnp->cn_nameptr. 215 */ 216 tdp = NULL; 217 mbnambuf_init(&nb); 218 /* 219 * The outer loop ranges over the clusters that make up the 220 * directory. Note that the root directory is different from all 221 * other directories. It has a fixed number of blocks that are not 222 * part of the pool of allocatable clusters. So, we treat it a 223 * little differently. The root directory starts at "cluster" 0. 224 */ 225 diroff = 0; 226 for (frcn = 0;; frcn++) { 227 error = pcbmap(dp, frcn, &bn, &cluster, &blsize); 228 if (error) { 229 if (error == E2BIG) 230 break; 231 return (error); 232 } 233 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 234 if (error) { 235 brelse(bp); 236 return (error); 237 } 238 for (blkoff = 0; blkoff < blsize; 239 blkoff += sizeof(struct direntry), 240 diroff += sizeof(struct direntry)) { 241 dep = (struct direntry *)(bp->b_data + blkoff); 242 /* 243 * If the slot is empty and we are still looking 244 * for an empty then remember this one. If the 245 * slot is not empty then check to see if it 246 * matches what we are looking for. If the slot 247 * has never been filled with anything, then the 248 * remainder of the directory has never been used, 249 * so there is no point in searching it. 250 */ 251 if (dep->deName[0] == SLOT_EMPTY || 252 dep->deName[0] == SLOT_DELETED) { 253 /* 254 * Drop memory of previous long matches 255 */ 256 chksum = -1; 257 mbnambuf_init(&nb); 258 259 if (slotcount < wincnt) { 260 slotcount++; 261 slotoffset = diroff; 262 } 263 if (dep->deName[0] == SLOT_EMPTY) { 264 brelse(bp); 265 goto notfound; 266 } 267 } else { 268 /* 269 * If there wasn't enough space for our winentries, 270 * forget about the empty space 271 */ 272 if (slotcount < wincnt) 273 slotcount = 0; 274 275 /* 276 * Check for Win95 long filename entry 277 */ 278 if (dep->deAttributes == ATTR_WIN95) { 279 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 280 continue; 281 282 chksum = win2unixfn(&nb, 283 (struct winentry *)dep, chksum, 284 pmp); 285 continue; 286 } 287 288 chksum = winChkName(&nb, 289 (const u_char *)cnp->cn_nameptr, unlen, 290 chksum, pmp); 291 if (chksum == -2) { 292 chksum = -1; 293 continue; 294 } 295 296 /* 297 * Ignore volume labels (anywhere, not just 298 * the root directory). 299 */ 300 if (dep->deAttributes & ATTR_VOLUME) { 301 chksum = -1; 302 continue; 303 } 304 305 /* 306 * Check for a checksum or name match 307 */ 308 chksum_ok = (chksum == winChksum(dep->deName)); 309 if (!chksum_ok 310 && (!olddos || bcmp(dosfilename, dep->deName, 11))) { 311 chksum = -1; 312 continue; 313 } 314 #ifdef MSDOSFS_DEBUG 315 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 316 blkoff, diroff); 317 #endif 318 /* 319 * Remember where this directory 320 * entry came from for whoever did 321 * this lookup. 322 */ 323 dp->de_fndoffset = diroff; 324 if (chksum_ok && nameiop == RENAME) { 325 /* 326 * Target had correct long name 327 * directory entries, reuse them 328 * as needed. 329 */ 330 dp->de_fndcnt = wincnt - 1; 331 } else { 332 /* 333 * Long name directory entries 334 * not present or corrupt, can only 335 * reuse dos directory entry. 336 */ 337 dp->de_fndcnt = 0; 338 } 339 340 goto found; 341 } 342 } /* for (blkoff = 0; .... */ 343 /* 344 * Release the buffer holding the directory cluster just 345 * searched. 346 */ 347 brelse(bp); 348 } /* for (frcn = 0; ; frcn++) */ 349 350 notfound: 351 /* 352 * We hold no disk buffers at this point. 353 */ 354 355 /* 356 * Fixup the slot description to point to the place where 357 * we might put the new DOS direntry (putting the Win95 358 * long name entries before that) 359 */ 360 if (!slotcount) { 361 slotcount = 1; 362 slotoffset = diroff; 363 } 364 if (wincnt > slotcount) 365 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 366 367 /* 368 * If we get here we didn't find the entry we were looking for. But 369 * that's ok if we are creating or renaming and are at the end of 370 * the pathname and the directory hasn't been removed. 371 */ 372 #ifdef MSDOSFS_DEBUG 373 printf("msdosfs_lookup(): op %d, refcnt %ld\n", 374 nameiop, dp->de_refcnt); 375 printf(" slotcount %d, slotoffset %d\n", 376 slotcount, slotoffset); 377 #endif 378 if ((nameiop == CREATE || nameiop == RENAME) && 379 (flags & ISLASTCN) && dp->de_refcnt != 0) { 380 /* 381 * Access for write is interpreted as allowing 382 * creation of files in the directory. 383 */ 384 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread); 385 if (error) 386 return (error); 387 /* 388 * Return an indication of where the new directory 389 * entry should be put. 390 */ 391 dp->de_fndoffset = slotoffset; 392 dp->de_fndcnt = wincnt - 1; 393 394 /* 395 * We return with the directory locked, so that 396 * the parameters we set up above will still be 397 * valid if we actually decide to do a direnter(). 398 * We return ni_vp == NULL to indicate that the entry 399 * does not currently exist; we leave a pointer to 400 * the (locked) directory inode in ndp->ni_dvp. 401 * The pathname buffer is saved so that the name 402 * can be obtained later. 403 * 404 * NB - if the directory is unlocked, then this 405 * information cannot be used. 406 */ 407 cnp->cn_flags |= SAVENAME; 408 return (EJUSTRETURN); 409 } 410 #if 0 411 /* 412 * Insert name into cache (as non-existent) if appropriate. 413 * 414 * XXX Negative caching is broken for msdosfs because the name 415 * cache doesn't understand peculiarities such as case insensitivity 416 * and 8.3 filenames. Hence, it may not invalidate all negative 417 * entries if a file with this name is later created. 418 */ 419 if ((cnp->cn_flags & MAKEENTRY) != 0) 420 cache_enter(vdp, *vpp, cnp); 421 #endif 422 return (ENOENT); 423 424 found: 425 /* 426 * NOTE: We still have the buffer with matched directory entry at 427 * this point. 428 */ 429 isadir = dep->deAttributes & ATTR_DIRECTORY; 430 scn = getushort(dep->deStartCluster); 431 if (FAT32(pmp)) { 432 scn |= getushort(dep->deHighClust) << 16; 433 if (scn == pmp->pm_rootdirblk) { 434 /* 435 * There should actually be 0 here. 436 * Just ignore the error. 437 */ 438 scn = MSDOSFSROOT; 439 } 440 } 441 442 if (isadir) { 443 cluster = scn; 444 if (cluster == MSDOSFSROOT) 445 blkoff = MSDOSFSROOT_OFS; 446 else 447 blkoff = 0; 448 } else if (cluster == MSDOSFSROOT) 449 blkoff = diroff; 450 451 /* 452 * Now release buf to allow deget to read the entry again. 453 * Reserving it here and giving it to deget could result 454 * in a deadlock. 455 */ 456 brelse(bp); 457 bp = NULL; 458 459 foundroot: 460 /* 461 * If we entered at foundroot, then we are looking for the . or .. 462 * entry of the filesystems root directory. isadir and scn were 463 * setup before jumping here. And, bp is already null. 464 */ 465 if (FAT32(pmp) && scn == MSDOSFSROOT) 466 scn = pmp->pm_rootdirblk; 467 468 if (dd_inum != NULL) { 469 *dd_inum = (uint64_t)pmp->pm_bpcluster * scn + blkoff; 470 return (0); 471 } 472 473 /* 474 * If deleting, and at end of pathname, return 475 * parameters which can be used to remove file. 476 */ 477 if (nameiop == DELETE && (flags & ISLASTCN)) { 478 /* 479 * Don't allow deleting the root. 480 */ 481 if (blkoff == MSDOSFSROOT_OFS) 482 return (EBUSY); 483 484 /* 485 * Write access to directory required to delete files. 486 */ 487 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread); 488 if (error) 489 return (error); 490 491 /* 492 * Return pointer to current entry in dp->i_offset. 493 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 494 */ 495 if (dp->de_StartCluster == scn && isadir) { /* "." */ 496 VREF(vdp); 497 *vpp = vdp; 498 return (0); 499 } 500 error = deget(pmp, cluster, blkoff, &tdp); 501 if (error) 502 return (error); 503 *vpp = DETOV(tdp); 504 return (0); 505 } 506 507 /* 508 * If rewriting (RENAME), return the inode and the 509 * information required to rewrite the present directory 510 * Must get inode of directory entry to verify it's a 511 * regular file, or empty directory. 512 */ 513 if (nameiop == RENAME && (flags & ISLASTCN)) { 514 if (blkoff == MSDOSFSROOT_OFS) 515 return (EBUSY); 516 517 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_thread); 518 if (error) 519 return (error); 520 521 /* 522 * Careful about locking second inode. 523 * This can only occur if the target is ".". 524 */ 525 if (dp->de_StartCluster == scn && isadir) 526 return (EISDIR); 527 528 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 529 return (error); 530 *vpp = DETOV(tdp); 531 cnp->cn_flags |= SAVENAME; 532 return (0); 533 } 534 535 /* 536 * Step through the translation in the name. We do not `vput' the 537 * directory because we may need it again if a symbolic link 538 * is relative to the current directory. Instead we save it 539 * unlocked as "pdp". We must get the target inode before unlocking 540 * the directory to insure that the inode will not be removed 541 * before we get it. We prevent deadlock by always fetching 542 * inodes from the root, moving down the directory tree. Thus 543 * when following backward pointers ".." we must unlock the 544 * parent directory before getting the requested directory. 545 */ 546 pdp = vdp; 547 if (flags & ISDOTDOT) { 548 dd_arg.cluster = cluster; 549 dd_arg.blkoff = blkoff; 550 error = vn_vget_ino_gen(vdp, msdosfs_deget_dotdot, 551 &dd_arg, cnp->cn_lkflags, vpp); 552 if (error != 0) { 553 *vpp = NULL; 554 return (error); 555 } 556 /* 557 * Recheck that ".." still points to the inode we 558 * looked up before pdp lock was dropped. 559 */ 560 error = msdosfs_lookup_(pdp, NULL, cnp, &inode1); 561 if (error) { 562 vput(*vpp); 563 *vpp = NULL; 564 return (error); 565 } 566 if (VTODE(*vpp)->de_inode != inode1) { 567 vput(*vpp); 568 goto restart; 569 } 570 } else if (dp->de_StartCluster == scn && isadir) { 571 VREF(vdp); /* we want ourself, ie "." */ 572 *vpp = vdp; 573 } else { 574 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 575 return (error); 576 *vpp = DETOV(tdp); 577 } 578 579 /* 580 * Insert name into cache if appropriate. 581 */ 582 if (cnp->cn_flags & MAKEENTRY) 583 cache_enter(vdp, *vpp, cnp); 584 return (0); 585 } 586 587 /* 588 * dep - directory entry to copy into the directory 589 * ddep - directory to add to 590 * depp - return the address of the denode for the created directory entry 591 * if depp != 0 592 * cnp - componentname needed for Win95 long filenames 593 */ 594 int 595 createde(struct denode *dep, struct denode *ddep, struct denode **depp, 596 struct componentname *cnp) 597 { 598 int error; 599 u_long dirclust, diroffset; 600 struct direntry *ndep; 601 struct msdosfsmount *pmp = ddep->de_pmp; 602 struct buf *bp; 603 daddr_t bn; 604 int blsize; 605 606 #ifdef MSDOSFS_DEBUG 607 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 608 dep, ddep, depp, cnp); 609 #endif 610 611 /* 612 * If no space left in the directory then allocate another cluster 613 * and chain it onto the end of the file. There is one exception 614 * to this. That is, if the root directory has no more space it 615 * can NOT be expanded. extendfile() checks for and fails attempts 616 * to extend the root directory. We just return an error in that 617 * case. 618 */ 619 if (ddep->de_fndoffset >= ddep->de_FileSize) { 620 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 621 - ddep->de_FileSize; 622 dirclust = de_clcount(pmp, diroffset); 623 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 624 if (error) { 625 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED); 626 return error; 627 } 628 629 /* 630 * Update the size of the directory 631 */ 632 ddep->de_FileSize += de_cn2off(pmp, dirclust); 633 } 634 635 /* 636 * We just read in the cluster with space. Copy the new directory 637 * entry in. Then write it to disk. NOTE: DOS directories 638 * do not get smaller as clusters are emptied. 639 */ 640 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 641 &bn, &dirclust, &blsize); 642 if (error) 643 return error; 644 diroffset = ddep->de_fndoffset; 645 if (dirclust != MSDOSFSROOT) 646 diroffset &= pmp->pm_crbomask; 647 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 648 brelse(bp); 649 return error; 650 } 651 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 652 653 DE_EXTERNALIZE(ndep, dep); 654 655 /* 656 * Now write the Win95 long name 657 */ 658 if (ddep->de_fndcnt > 0) { 659 u_int8_t chksum = winChksum(ndep->deName); 660 const u_char *un = (const u_char *)cnp->cn_nameptr; 661 int unlen = cnp->cn_namelen; 662 int cnt = 1; 663 664 while (--ddep->de_fndcnt >= 0) { 665 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 666 if (DOINGASYNC(DETOV(ddep))) 667 bdwrite(bp); 668 else if ((error = bwrite(bp)) != 0) 669 return error; 670 671 ddep->de_fndoffset -= sizeof(struct direntry); 672 error = pcbmap(ddep, 673 de_cluster(pmp, 674 ddep->de_fndoffset), 675 &bn, 0, &blsize); 676 if (error) 677 return error; 678 679 error = bread(pmp->pm_devvp, bn, blsize, 680 NOCRED, &bp); 681 if (error) { 682 brelse(bp); 683 return error; 684 } 685 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 686 } else { 687 ndep--; 688 ddep->de_fndoffset -= sizeof(struct direntry); 689 } 690 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 691 cnt++, chksum, pmp)) 692 break; 693 } 694 } 695 696 if (DOINGASYNC(DETOV(ddep))) 697 bdwrite(bp); 698 else if ((error = bwrite(bp)) != 0) 699 return error; 700 701 /* 702 * If they want us to return with the denode gotten. 703 */ 704 if (depp) { 705 if (dep->de_Attributes & ATTR_DIRECTORY) { 706 dirclust = dep->de_StartCluster; 707 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 708 dirclust = MSDOSFSROOT; 709 if (dirclust == MSDOSFSROOT) 710 diroffset = MSDOSFSROOT_OFS; 711 else 712 diroffset = 0; 713 } 714 return deget(pmp, dirclust, diroffset, depp); 715 } 716 717 return 0; 718 } 719 720 /* 721 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 722 * return 0 if not empty or error. 723 */ 724 int 725 dosdirempty(struct denode *dep) 726 { 727 int blsize; 728 int error; 729 u_long cn; 730 daddr_t bn; 731 struct buf *bp; 732 struct msdosfsmount *pmp = dep->de_pmp; 733 struct direntry *dentp; 734 735 /* 736 * Since the filesize field in directory entries for a directory is 737 * zero, we just have to feel our way through the directory until 738 * we hit end of file. 739 */ 740 for (cn = 0;; cn++) { 741 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 742 if (error == E2BIG) 743 return (1); /* it's empty */ 744 return (0); 745 } 746 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 747 if (error) { 748 brelse(bp); 749 return (0); 750 } 751 for (dentp = (struct direntry *)bp->b_data; 752 (char *)dentp < bp->b_data + blsize; 753 dentp++) { 754 if (dentp->deName[0] != SLOT_DELETED && 755 (dentp->deAttributes & ATTR_VOLUME) == 0) { 756 /* 757 * In dos directories an entry whose name 758 * starts with SLOT_EMPTY (0) starts the 759 * beginning of the unused part of the 760 * directory, so we can just return that it 761 * is empty. 762 */ 763 if (dentp->deName[0] == SLOT_EMPTY) { 764 brelse(bp); 765 return (1); 766 } 767 /* 768 * Any names other than "." and ".." in a 769 * directory mean it is not empty. 770 */ 771 if (bcmp(dentp->deName, ". ", 11) && 772 bcmp(dentp->deName, ".. ", 11)) { 773 brelse(bp); 774 #ifdef MSDOSFS_DEBUG 775 printf("dosdirempty(): entry found %02x, %02x\n", 776 dentp->deName[0], dentp->deName[1]); 777 #endif 778 return (0); /* not empty */ 779 } 780 } 781 } 782 brelse(bp); 783 } 784 /* NOTREACHED */ 785 } 786 787 /* 788 * Check to see if the directory described by target is in some 789 * subdirectory of source. This prevents something like the following from 790 * succeeding and leaving a bunch or files and directories orphaned. mv 791 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 792 * 793 * source - the inode for /a/b/c 794 * target - the inode for /a/b/c/d/e/f 795 * 796 * Returns 0 if target is NOT a subdirectory of source. 797 * Otherwise returns a non-zero error number. 798 * The target inode is always unlocked on return. 799 */ 800 int 801 doscheckpath(struct denode *source, struct denode *target) 802 { 803 daddr_t scn; 804 struct msdosfsmount *pmp; 805 struct direntry *ep; 806 struct denode *dep; 807 struct buf *bp = NULL; 808 int error = 0; 809 810 dep = target; 811 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 812 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 813 error = ENOTDIR; 814 goto out; 815 } 816 if (dep->de_StartCluster == source->de_StartCluster) { 817 error = EEXIST; 818 goto out; 819 } 820 if (dep->de_StartCluster == MSDOSFSROOT) 821 goto out; 822 pmp = dep->de_pmp; 823 #ifdef DIAGNOSTIC 824 if (pmp != source->de_pmp) 825 panic("doscheckpath: source and target on different filesystems"); 826 #endif 827 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 828 goto out; 829 830 for (;;) { 831 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 832 error = ENOTDIR; 833 break; 834 } 835 scn = dep->de_StartCluster; 836 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 837 pmp->pm_bpcluster, NOCRED, &bp); 838 if (error) 839 break; 840 841 ep = (struct direntry *) bp->b_data + 1; 842 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 843 bcmp(ep->deName, ".. ", 11) != 0) { 844 error = ENOTDIR; 845 break; 846 } 847 scn = getushort(ep->deStartCluster); 848 if (FAT32(pmp)) 849 scn |= getushort(ep->deHighClust) << 16; 850 851 if (scn == source->de_StartCluster) { 852 error = EINVAL; 853 break; 854 } 855 if (scn == MSDOSFSROOT) 856 break; 857 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 858 /* 859 * scn should be 0 in this case, 860 * but we silently ignore the error. 861 */ 862 break; 863 } 864 865 vput(DETOV(dep)); 866 brelse(bp); 867 bp = NULL; 868 /* NOTE: deget() clears dep on error */ 869 if ((error = deget(pmp, scn, 0, &dep)) != 0) 870 break; 871 } 872 out:; 873 if (bp) 874 brelse(bp); 875 #ifdef MSDOSFS_DEBUG 876 if (error == ENOTDIR) 877 printf("doscheckpath(): .. not a directory?\n"); 878 #endif 879 if (dep != NULL) 880 vput(DETOV(dep)); 881 return (error); 882 } 883 884 /* 885 * Read in the disk block containing the directory entry (dirclu, dirofs) 886 * and return the address of the buf header, and the address of the 887 * directory entry within the block. 888 */ 889 int 890 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 891 struct buf **bpp, struct direntry **epp) 892 { 893 int error; 894 daddr_t bn; 895 int blsize; 896 897 blsize = pmp->pm_bpcluster; 898 if (dirclust == MSDOSFSROOT 899 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 900 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 901 bn = detobn(pmp, dirclust, diroffset); 902 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 903 brelse(*bpp); 904 *bpp = NULL; 905 return (error); 906 } 907 if (epp) 908 *epp = bptoep(pmp, *bpp, diroffset); 909 return (0); 910 } 911 912 /* 913 * Read in the disk block containing the directory entry dep came from and 914 * return the address of the buf header, and the address of the directory 915 * entry within the block. 916 */ 917 int 918 readde(struct denode *dep, struct buf **bpp, struct direntry **epp) 919 { 920 921 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 922 bpp, epp)); 923 } 924 925 /* 926 * Remove a directory entry. At this point the file represented by the 927 * directory entry to be removed is still full length until no one has it 928 * open. When the file no longer being used msdosfs_inactive() is called 929 * and will truncate the file to 0 length. When the vnode containing the 930 * denode is needed for some other purpose by VFS it will call 931 * msdosfs_reclaim() which will remove the denode from the denode cache. 932 * 933 * pdep directory where the entry is removed 934 * dep file to be removed 935 */ 936 int 937 removede(struct denode *pdep, struct denode *dep) 938 { 939 int error; 940 struct direntry *ep; 941 struct buf *bp; 942 daddr_t bn; 943 int blsize; 944 struct msdosfsmount *pmp = pdep->de_pmp; 945 u_long offset = pdep->de_fndoffset; 946 947 #ifdef MSDOSFS_DEBUG 948 printf("removede(): filename %s, dep %p, offset %08lx\n", 949 dep->de_Name, dep, offset); 950 #endif 951 952 dep->de_refcnt--; 953 offset += sizeof(struct direntry); 954 do { 955 offset -= sizeof(struct direntry); 956 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 957 if (error) 958 return error; 959 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 960 if (error) { 961 brelse(bp); 962 return error; 963 } 964 ep = bptoep(pmp, bp, offset); 965 /* 966 * Check whether, if we came here the second time, i.e. 967 * when underflowing into the previous block, the last 968 * entry in this block is a longfilename entry, too. 969 */ 970 if (ep->deAttributes != ATTR_WIN95 971 && offset != pdep->de_fndoffset) { 972 brelse(bp); 973 break; 974 } 975 offset += sizeof(struct direntry); 976 while (1) { 977 /* 978 * We are a bit aggressive here in that we delete any Win95 979 * entries preceding this entry, not just the ones we "own". 980 * Since these presumably aren't valid anyway, 981 * there should be no harm. 982 */ 983 offset -= sizeof(struct direntry); 984 ep--->deName[0] = SLOT_DELETED; 985 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 986 || !(offset & pmp->pm_crbomask) 987 || ep->deAttributes != ATTR_WIN95) 988 break; 989 } 990 if (DOINGASYNC(DETOV(pdep))) 991 bdwrite(bp); 992 else if ((error = bwrite(bp)) != 0) 993 return error; 994 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 995 && !(offset & pmp->pm_crbomask) 996 && offset); 997 return 0; 998 } 999 1000 /* 1001 * Create a unique DOS name in dvp 1002 */ 1003 int 1004 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp) 1005 { 1006 struct msdosfsmount *pmp = dep->de_pmp; 1007 struct direntry *dentp; 1008 int gen; 1009 int blsize; 1010 u_long cn; 1011 daddr_t bn; 1012 struct buf *bp; 1013 int error; 1014 1015 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 1016 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 1017 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL); 1018 1019 for (gen = 1;; gen++) { 1020 /* 1021 * Generate DOS name with generation number 1022 */ 1023 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 1024 cnp->cn_namelen, gen, pmp)) 1025 return gen == 1 ? EINVAL : EEXIST; 1026 1027 /* 1028 * Now look for a dir entry with this exact name 1029 */ 1030 for (cn = error = 0; !error; cn++) { 1031 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 1032 if (error == E2BIG) /* EOF reached and not found */ 1033 return 0; 1034 return error; 1035 } 1036 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 1037 if (error) { 1038 brelse(bp); 1039 return error; 1040 } 1041 for (dentp = (struct direntry *)bp->b_data; 1042 (char *)dentp < bp->b_data + blsize; 1043 dentp++) { 1044 if (dentp->deName[0] == SLOT_EMPTY) { 1045 /* 1046 * Last used entry and not found 1047 */ 1048 brelse(bp); 1049 return 0; 1050 } 1051 /* 1052 * Ignore volume labels and Win95 entries 1053 */ 1054 if (dentp->deAttributes & ATTR_VOLUME) 1055 continue; 1056 if (!bcmp(dentp->deName, cp, 11)) { 1057 error = EEXIST; 1058 break; 1059 } 1060 } 1061 brelse(bp); 1062 } 1063 } 1064 } 1065 1066 /* 1067 * Find any Win'95 long filename entry in directory dep 1068 */ 1069 int 1070 findwin95(struct denode *dep) 1071 { 1072 struct msdosfsmount *pmp = dep->de_pmp; 1073 struct direntry *dentp; 1074 int blsize, win95; 1075 u_long cn; 1076 daddr_t bn; 1077 struct buf *bp; 1078 1079 win95 = 1; 1080 /* 1081 * Read through the directory looking for Win'95 entries 1082 * Note: Error currently handled just as EOF XXX 1083 */ 1084 for (cn = 0;; cn++) { 1085 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1086 return (win95); 1087 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1088 brelse(bp); 1089 return (win95); 1090 } 1091 for (dentp = (struct direntry *)bp->b_data; 1092 (char *)dentp < bp->b_data + blsize; 1093 dentp++) { 1094 if (dentp->deName[0] == SLOT_EMPTY) { 1095 /* 1096 * Last used entry and not found 1097 */ 1098 brelse(bp); 1099 return (win95); 1100 } 1101 if (dentp->deName[0] == SLOT_DELETED) { 1102 /* 1103 * Ignore deleted files 1104 * Note: might be an indication of Win'95 anyway XXX 1105 */ 1106 continue; 1107 } 1108 if (dentp->deAttributes == ATTR_WIN95) { 1109 brelse(bp); 1110 return 1; 1111 } 1112 win95 = 0; 1113 } 1114 brelse(bp); 1115 } 1116 }
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