msdosfs_lookup.c revision 33751
1/* $Id: msdosfs_lookup.c,v 1.17 1998/02/22 17:26:27 ache Exp $ */ 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/namei.h> 53#include <sys/buf.h> 54#include <sys/vnode.h> 55#include <sys/mount.h> 56#include <sys/systm.h> 57 58#include <msdosfs/bpb.h> 59#include <msdosfs/direntry.h> 60#include <msdosfs/denode.h> 61#include <msdosfs/msdosfsmount.h> 62#include <msdosfs/fat.h> 63 64static int markdeleted __P((struct msdosfsmount *pmp, u_long dirclust, 65 u_long diroffset)); 66 67/* 68 * When we search a directory the blocks containing directory entries are 69 * read and examined. The directory entries contain information that would 70 * normally be in the inode of a unix filesystem. This means that some of 71 * a directory's contents may also be in memory resident denodes (sort of 72 * an inode). This can cause problems if we are searching while some other 73 * process is modifying a directory. To prevent one process from accessing 74 * incompletely modified directory information we depend upon being the 75 * sole owner of a directory block. bread/brelse provide this service. 76 * This being the case, when a process modifies a directory it must first 77 * acquire the disk block that contains the directory entry to be modified. 78 * Then update the disk block and the denode, and then write the disk block 79 * out to disk. This way disk blocks containing directory entries and in 80 * memory denode's will be in synch. 81 */ 82int 83msdosfs_lookup(ap) 84 struct vop_cachedlookup_args /* { 85 struct vnode *a_dvp; 86 struct vnode **a_vpp; 87 struct componentname *a_cnp; 88 } */ *ap; 89{ 90 struct vnode *vdp = ap->a_dvp; 91 struct vnode **vpp = ap->a_vpp; 92 struct componentname *cnp = ap->a_cnp; 93 daddr_t bn; 94 int error; 95 int lockparent; 96 int wantparent; 97 int slotcount; 98 int slotoffset = 0; 99 int frcn; 100 u_long cluster; 101 int blkoff; 102 int diroff; 103 int blsize; 104 int isadir; /* ~0 if found direntry is a directory */ 105 u_long scn; /* starting cluster number */ 106 struct vnode *pdp; 107 struct denode *dp; 108 struct denode *tdp; 109 struct msdosfsmount *pmp; 110 struct buf *bp = 0; 111 struct direntry *dep = NULL; 112 struct ucred *cred = cnp->cn_cred; 113 u_char dosfilename[12]; 114 int flags = cnp->cn_flags; 115 int nameiop = cnp->cn_nameiop; 116 struct proc *p = cnp->cn_proc; 117 118 int wincnt = 1; 119 int chksum = -1; 120 int olddos = 1; 121 122#ifdef MSDOSFS_DEBUG 123 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr); 124#endif 125 dp = VTODE(vdp); 126 pmp = dp->de_pmp; 127 *vpp = NULL; 128 lockparent = flags & LOCKPARENT; 129 wantparent = flags & (LOCKPARENT | WANTPARENT); 130#ifdef MSDOSFS_DEBUG 131 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n", 132 vdp, dp, dp->de_Attributes); 133#endif 134 135 /* 136 * If they are going after the . or .. entry in the root directory, 137 * they won't find it. DOS filesystems don't have them in the root 138 * directory. So, we fake it. deget() is in on this scam too. 139 */ 140 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' && 141 (cnp->cn_namelen == 1 || 142 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) { 143 isadir = ATTR_DIRECTORY; 144 scn = MSDOSFSROOT; 145#ifdef MSDOSFS_DEBUG 146 printf("msdosfs_lookup(): looking for . or .. in root directory\n"); 147#endif 148 cluster = MSDOSFSROOT; 149 blkoff = MSDOSFSROOT_OFS; 150 goto foundroot; 151 } 152 153 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 154 cnp->cn_namelen, 0)) { 155 case 0: 156 return (EINVAL); 157 case 1: 158 break; 159 case 2: 160 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 161 cnp->cn_namelen) + 1; 162 break; 163 case 3: 164 olddos = 0; 165 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 166 cnp->cn_namelen) + 1; 167 break; 168 } 169 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 170 wincnt = 1; 171 172 /* 173 * Suppress search for slots unless creating 174 * file and at end of pathname, in which case 175 * we watch for a place to put the new file in 176 * case it doesn't already exist. 177 */ 178 slotcount = wincnt; 179 if ((nameiop == CREATE || nameiop == RENAME) && 180 (flags & ISLASTCN)) 181 slotcount = 0; 182 183#ifdef MSDOSFS_DEBUG 184 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n", 185 dosfilename, cnp->cn_namelen); 186#endif 187 /* 188 * Search the directory pointed at by vdp for the name pointed at 189 * by cnp->cn_nameptr. 190 */ 191 tdp = NULL; 192 /* 193 * The outer loop ranges over the clusters that make up the 194 * directory. Note that the root directory is different from all 195 * other directories. It has a fixed number of blocks that are not 196 * part of the pool of allocatable clusters. So, we treat it a 197 * little differently. The root directory starts at "cluster" 0. 198 */ 199 diroff = 0; 200 for (frcn = 0;; frcn++) { 201 error = pcbmap(dp, frcn, &bn, &cluster, &blsize); 202 if (error) { 203 if (error == E2BIG) 204 break; 205 return (error); 206 } 207 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 208 if (error) { 209 brelse(bp); 210 return (error); 211 } 212 for (blkoff = 0; blkoff < blsize; 213 blkoff += sizeof(struct direntry), 214 diroff += sizeof(struct direntry)) { 215 dep = (struct direntry *)(bp->b_data + blkoff); 216 /* 217 * If the slot is empty and we are still looking 218 * for an empty then remember this one. If the 219 * slot is not empty then check to see if it 220 * matches what we are looking for. If the slot 221 * has never been filled with anything, then the 222 * remainder of the directory has never been used, 223 * so there is no point in searching it. 224 */ 225 if (dep->deName[0] == SLOT_EMPTY || 226 dep->deName[0] == SLOT_DELETED) { 227 /* 228 * Drop memory of previous long matches 229 */ 230 chksum = -1; 231 232 if (slotcount < wincnt) { 233 slotcount++; 234 slotoffset = diroff; 235 } 236 if (dep->deName[0] == SLOT_EMPTY) { 237 brelse(bp); 238 goto notfound; 239 } 240 } else { 241 /* 242 * If there wasn't enough space for our winentries, 243 * forget about the empty space 244 */ 245 if (slotcount < wincnt) 246 slotcount = 0; 247 248 /* 249 * Check for Win95 long filename entry 250 */ 251 if (dep->deAttributes == ATTR_WIN95) { 252 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 253 continue; 254 255 chksum = winChkName((const u_char *)cnp->cn_nameptr, 256 cnp->cn_namelen, 257 (struct winentry *)dep, 258 chksum, 259 (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) ? 260 pmp->pm_u2w : NULL); 261 continue; 262 } 263 264 /* 265 * Ignore volume labels (anywhere, not just 266 * the root directory). 267 */ 268 if (dep->deAttributes & ATTR_VOLUME) { 269 chksum = -1; 270 continue; 271 } 272 273 /* 274 * Check for a checksum or name match 275 */ 276 if (chksum != winChksum(dep->deName) 277 && (!olddos || bcmp(dosfilename, dep->deName, 11))) { 278 chksum = -1; 279 continue; 280 } 281#ifdef MSDOSFS_DEBUG 282 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 283 blkoff, diroff); 284#endif 285 /* 286 * Remember where this directory 287 * entry came from for whoever did 288 * this lookup. 289 */ 290 dp->de_fndoffset = diroff; 291 dp->de_fndcnt = 0; /* unused anyway */ 292 293 goto found; 294 } 295 } /* for (blkoff = 0; .... */ 296 /* 297 * Release the buffer holding the directory cluster just 298 * searched. 299 */ 300 brelse(bp); 301 } /* for (frcn = 0; ; frcn++) */ 302 303notfound: 304 /* 305 * We hold no disk buffers at this point. 306 */ 307 308 /* 309 * Fixup the slot description to point to the place where 310 * we might put the new DOS direntry (putting the Win95 311 * long name entries before that) 312 */ 313 if (!slotcount) { 314 slotcount = 1; 315 slotoffset = diroff; 316 } 317 if (wincnt > slotcount) 318 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 319 320 /* 321 * If we get here we didn't find the entry we were looking for. But 322 * that's ok if we are creating or renaming and are at the end of 323 * the pathname and the directory hasn't been removed. 324 */ 325#ifdef MSDOSFS_DEBUG 326 printf("msdosfs_lookup(): op %d, refcnt %ld\n", 327 nameiop, dp->de_refcnt); 328 printf(" slotcount %d, slotoffset %d\n", 329 slotcount, slotoffset); 330#endif 331 if ((nameiop == CREATE || nameiop == RENAME) && 332 (flags & ISLASTCN) && dp->de_refcnt != 0) { 333 /* 334 * Access for write is interpreted as allowing 335 * creation of files in the directory. 336 */ 337 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 338 if (error) 339 return (error); 340 /* 341 * Return an indication of where the new directory 342 * entry should be put. 343 */ 344 dp->de_fndoffset = slotoffset; 345 dp->de_fndcnt = wincnt - 1; 346 347 /* 348 * We return with the directory locked, so that 349 * the parameters we set up above will still be 350 * valid if we actually decide to do a direnter(). 351 * We return ni_vp == NULL to indicate that the entry 352 * does not currently exist; we leave a pointer to 353 * the (locked) directory inode in ndp->ni_dvp. 354 * The pathname buffer is saved so that the name 355 * can be obtained later. 356 * 357 * NB - if the directory is unlocked, then this 358 * information cannot be used. 359 */ 360 cnp->cn_flags |= SAVENAME; 361 if (!lockparent) 362 VOP_UNLOCK(vdp, 0, p); 363 return (EJUSTRETURN); 364 } 365 /* 366 * Insert name into cache (as non-existent) if appropriate. 367 */ 368 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 369 cache_enter(vdp, *vpp, cnp); 370 return (ENOENT); 371 372found: 373 /* 374 * NOTE: We still have the buffer with matched directory entry at 375 * this point. 376 */ 377 isadir = dep->deAttributes & ATTR_DIRECTORY; 378 scn = getushort(dep->deStartCluster); 379 if (FAT32(pmp)) { 380 scn |= getushort(dep->deHighClust) << 16; 381 if (scn == pmp->pm_rootdirblk) { 382 /* 383 * There should actually be 0 here. 384 * Just ignore the error. 385 */ 386 scn = MSDOSFSROOT; 387 } 388 } 389 390 if (isadir) { 391 cluster = scn; 392 if (cluster == MSDOSFSROOT) 393 blkoff = MSDOSFSROOT_OFS; 394 else 395 blkoff = 0; 396 } else if (cluster == MSDOSFSROOT) 397 blkoff = diroff; 398 399 /* 400 * Now release buf to allow deget to read the entry again. 401 * Reserving it here and giving it to deget could result 402 * in a deadlock. 403 */ 404 brelse(bp); 405 bp = 0; 406 407foundroot: 408 /* 409 * If we entered at foundroot, then we are looking for the . or .. 410 * entry of the filesystems root directory. isadir and scn were 411 * setup before jumping here. And, bp is already null. 412 */ 413 if (FAT32(pmp) && scn == MSDOSFSROOT) 414 scn = pmp->pm_rootdirblk; 415 416 /* 417 * If deleting, and at end of pathname, return 418 * parameters which can be used to remove file. 419 * If the wantparent flag isn't set, we return only 420 * the directory (in ndp->ni_dvp), otherwise we go 421 * on and lock the inode, being careful with ".". 422 */ 423 if (nameiop == DELETE && (flags & ISLASTCN)) { 424 /* 425 * Don't allow deleting the root. 426 */ 427 if (blkoff == MSDOSFSROOT_OFS) 428 return EROFS; /* really? XXX */ 429 430 /* 431 * Write access to directory required to delete files. 432 */ 433 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 434 if (error) 435 return (error); 436 437 /* 438 * Return pointer to current entry in dp->i_offset. 439 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 440 */ 441 if (dp->de_StartCluster == scn && isadir) { /* "." */ 442 VREF(vdp); 443 *vpp = vdp; 444 return (0); 445 } 446 error = deget(pmp, cluster, blkoff, &tdp); 447 if (error) 448 return (error); 449 *vpp = DETOV(tdp); 450 if (!lockparent) 451 VOP_UNLOCK(vdp, 0, p); 452 return (0); 453 } 454 455 /* 456 * If rewriting (RENAME), return the inode and the 457 * information required to rewrite the present directory 458 * Must get inode of directory entry to verify it's a 459 * regular file, or empty directory. 460 */ 461 if (nameiop == RENAME && wantparent && 462 (flags & ISLASTCN)) { 463 if (blkoff == MSDOSFSROOT_OFS) 464 return EROFS; /* really? XXX */ 465 466 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 467 if (error) 468 return (error); 469 470 /* 471 * Careful about locking second inode. 472 * This can only occur if the target is ".". 473 */ 474 if (dp->de_StartCluster == scn && isadir) 475 return (EISDIR); 476 477 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 478 return (error); 479 *vpp = DETOV(tdp); 480 cnp->cn_flags |= SAVENAME; 481 if (!lockparent) 482 VOP_UNLOCK(vdp, 0, p); 483 return (0); 484 } 485 486 /* 487 * Step through the translation in the name. We do not `vput' the 488 * directory because we may need it again if a symbolic link 489 * is relative to the current directory. Instead we save it 490 * unlocked as "pdp". We must get the target inode before unlocking 491 * the directory to insure that the inode will not be removed 492 * before we get it. We prevent deadlock by always fetching 493 * inodes from the root, moving down the directory tree. Thus 494 * when following backward pointers ".." we must unlock the 495 * parent directory before getting the requested directory. 496 * There is a potential race condition here if both the current 497 * and parent directories are removed before the VFS_VGET for the 498 * inode associated with ".." returns. We hope that this occurs 499 * infrequently since we cannot avoid this race condition without 500 * implementing a sophisticated deadlock detection algorithm. 501 * Note also that this simple deadlock detection scheme will not 502 * work if the file system has any hard links other than ".." 503 * that point backwards in the directory structure. 504 */ 505 pdp = vdp; 506 if (flags & ISDOTDOT) { 507 VOP_UNLOCK(pdp, 0, p); 508 error = deget(pmp, cluster, blkoff, &tdp); 509 if (error) { 510 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 511 return (error); 512 } 513 if (lockparent && (flags & ISLASTCN) && 514 (error = vn_lock(pdp, LK_EXCLUSIVE, p))) { 515 vput(DETOV(tdp)); 516 return (error); 517 } 518 *vpp = DETOV(tdp); 519 } else if (dp->de_StartCluster == scn && isadir) { 520 VREF(vdp); /* we want ourself, ie "." */ 521 *vpp = vdp; 522 } else { 523 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 524 return (error); 525 if (!lockparent || !(flags & ISLASTCN)) 526 VOP_UNLOCK(pdp, 0, p); 527 *vpp = DETOV(tdp); 528 } 529 530 /* 531 * Insert name into cache if appropriate. 532 */ 533 if (cnp->cn_flags & MAKEENTRY) 534 cache_enter(vdp, *vpp, cnp); 535 return (0); 536} 537 538/* 539 * dep - directory entry to copy into the directory 540 * ddep - directory to add to 541 * depp - return the address of the denode for the created directory entry 542 * if depp != 0 543 * cnp - componentname needed for Win95 long filenames 544 */ 545int 546createde(dep, ddep, depp, cnp) 547 struct denode *dep; 548 struct denode *ddep; 549 struct denode **depp; 550 struct componentname *cnp; 551{ 552 int error; 553 u_long dirclust, diroffset; 554 struct direntry *ndep; 555 struct msdosfsmount *pmp = ddep->de_pmp; 556 struct buf *bp; 557 daddr_t bn; 558 int blsize; 559 560#ifdef MSDOSFS_DEBUG 561 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 562 dep, ddep, depp, cnp); 563#endif 564 565 /* 566 * If no space left in the directory then allocate another cluster 567 * and chain it onto the end of the file. There is one exception 568 * to this. That is, if the root directory has no more space it 569 * can NOT be expanded. extendfile() checks for and fails attempts 570 * to extend the root directory. We just return an error in that 571 * case. 572 */ 573 if (ddep->de_fndoffset >= ddep->de_FileSize) { 574 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 575 - ddep->de_FileSize; 576 dirclust = de_clcount(pmp, diroffset); 577 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 578 if (error) { 579 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL); 580 return error; 581 } 582 583 /* 584 * Update the size of the directory 585 */ 586 ddep->de_FileSize += de_cn2off(pmp, dirclust); 587 } 588 589 /* 590 * We just read in the cluster with space. Copy the new directory 591 * entry in. Then write it to disk. NOTE: DOS directories 592 * do not get smaller as clusters are emptied. 593 */ 594 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 595 &bn, &dirclust, &blsize); 596 if (error) 597 return error; 598 diroffset = ddep->de_fndoffset; 599 if (dirclust != MSDOSFSROOT) 600 diroffset &= pmp->pm_crbomask; 601 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 602 brelse(bp); 603 return error; 604 } 605 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 606 607 DE_EXTERNALIZE(ndep, dep); 608 609 /* 610 * Now write the Win95 long name 611 */ 612 if (ddep->de_fndcnt > 0) { 613 u_int8_t chksum = winChksum(ndep->deName); 614 const u_char *un = (const u_char *)cnp->cn_nameptr; 615 int unlen = cnp->cn_namelen; 616 int cnt = 1; 617 618 while (--ddep->de_fndcnt >= 0) { 619 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 620 if ((error = bwrite(bp)) != 0) 621 return error; 622 623 ddep->de_fndoffset -= sizeof(struct direntry); 624 error = pcbmap(ddep, 625 de_cluster(pmp, 626 ddep->de_fndoffset), 627 &bn, 0, &blsize); 628 if (error) 629 return error; 630 631 error = bread(pmp->pm_devvp, bn, blsize, 632 NOCRED, &bp); 633 if (error) { 634 brelse(bp); 635 return error; 636 } 637 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 638 } else { 639 ndep--; 640 ddep->de_fndoffset -= sizeof(struct direntry); 641 } 642 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 643 cnt++, chksum, 644 (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) ? 645 pmp->pm_u2w : NULL)); 646 break; 647 } 648 } 649 650 if ((error = bwrite(bp)) != 0) 651 return error; 652 653 /* 654 * If they want us to return with the denode gotten. 655 */ 656 if (depp) { 657 if (dep->de_Attributes & ATTR_DIRECTORY) { 658 dirclust = dep->de_StartCluster; 659 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 660 dirclust = MSDOSFSROOT; 661 if (dirclust == MSDOSFSROOT) 662 diroffset = MSDOSFSROOT_OFS; 663 else 664 diroffset = 0; 665 } 666 return deget(pmp, dirclust, diroffset, depp); 667 } 668 669 return 0; 670} 671 672/* 673 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 674 * return 0 if not empty or error. 675 */ 676int 677dosdirempty(dep) 678 struct denode *dep; 679{ 680 int blsize; 681 int error; 682 u_long cn; 683 daddr_t bn; 684 struct buf *bp; 685 struct msdosfsmount *pmp = dep->de_pmp; 686 struct direntry *dentp; 687 688 /* 689 * Since the filesize field in directory entries for a directory is 690 * zero, we just have to feel our way through the directory until 691 * we hit end of file. 692 */ 693 for (cn = 0;; cn++) { 694 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 695 if (error == E2BIG) 696 return (1); /* it's empty */ 697 return (0); 698 } 699 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 700 if (error) { 701 brelse(bp); 702 return (0); 703 } 704 for (dentp = (struct direntry *)bp->b_data; 705 (char *)dentp < bp->b_data + blsize; 706 dentp++) { 707 if (dentp->deName[0] != SLOT_DELETED && 708 (dentp->deAttributes & ATTR_VOLUME) == 0) { 709 /* 710 * In dos directories an entry whose name 711 * starts with SLOT_EMPTY (0) starts the 712 * beginning of the unused part of the 713 * directory, so we can just return that it 714 * is empty. 715 */ 716 if (dentp->deName[0] == SLOT_EMPTY) { 717 brelse(bp); 718 return (1); 719 } 720 /* 721 * Any names other than "." and ".." in a 722 * directory mean it is not empty. 723 */ 724 if (bcmp(dentp->deName, ". ", 11) && 725 bcmp(dentp->deName, ".. ", 11)) { 726 brelse(bp); 727#ifdef MSDOSFS_DEBUG 728 printf("dosdirempty(): entry found %02x, %02x\n", 729 dentp->deName[0], dentp->deName[1]); 730#endif 731 return (0); /* not empty */ 732 } 733 } 734 } 735 brelse(bp); 736 } 737 /* NOTREACHED */ 738} 739 740/* 741 * Check to see if the directory described by target is in some 742 * subdirectory of source. This prevents something like the following from 743 * succeeding and leaving a bunch or files and directories orphaned. mv 744 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 745 * 746 * source - the inode for /a/b/c 747 * target - the inode for /a/b/c/d/e/f 748 * 749 * Returns 0 if target is NOT a subdirectory of source. 750 * Otherwise returns a non-zero error number. 751 * The target inode is always unlocked on return. 752 */ 753int 754doscheckpath(source, target) 755 struct denode *source; 756 struct denode *target; 757{ 758 daddr_t scn; 759 struct msdosfsmount *pmp; 760 struct direntry *ep; 761 struct denode *dep; 762 struct buf *bp = NULL; 763 int error = 0; 764 765 dep = target; 766 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 767 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 768 error = ENOTDIR; 769 goto out; 770 } 771 if (dep->de_StartCluster == source->de_StartCluster) { 772 error = EEXIST; 773 goto out; 774 } 775 if (dep->de_StartCluster == MSDOSFSROOT) 776 goto out; 777 pmp = dep->de_pmp; 778#ifdef DIAGNOSTIC 779 if (pmp != source->de_pmp) 780 panic("doscheckpath: source and target on different filesystems"); 781#endif 782 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 783 goto out; 784 785 for (;;) { 786 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 787 error = ENOTDIR; 788 break; 789 } 790 scn = dep->de_StartCluster; 791 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 792 pmp->pm_bpcluster, NOCRED, &bp); 793 if (error) 794 break; 795 796 ep = (struct direntry *) bp->b_data + 1; 797 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 798 bcmp(ep->deName, ".. ", 11) != 0) { 799 error = ENOTDIR; 800 break; 801 } 802 scn = getushort(ep->deStartCluster); 803 if (FAT32(pmp)) 804 scn |= getushort(ep->deHighClust) << 16; 805 806 if (scn == source->de_StartCluster) { 807 error = EINVAL; 808 break; 809 } 810 if (scn == MSDOSFSROOT) 811 break; 812 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 813 /* 814 * scn should be 0 in this case, 815 * but we silently ignore the error. 816 */ 817 break; 818 } 819 820 vput(DETOV(dep)); 821 brelse(bp); 822 bp = NULL; 823 /* NOTE: deget() clears dep on error */ 824 if ((error = deget(pmp, scn, 0, &dep)) != 0) 825 break; 826 } 827out:; 828 if (bp) 829 brelse(bp); 830 if (error == ENOTDIR) 831 printf("doscheckpath(): .. not a directory?\n"); 832 if (dep != NULL) 833 vput(DETOV(dep)); 834 return (error); 835} 836 837/* 838 * Read in the disk block containing the directory entry (dirclu, dirofs) 839 * and return the address of the buf header, and the address of the 840 * directory entry within the block. 841 */ 842int 843readep(pmp, dirclust, diroffset, bpp, epp) 844 struct msdosfsmount *pmp; 845 u_long dirclust, diroffset; 846 struct buf **bpp; 847 struct direntry **epp; 848{ 849 int error; 850 daddr_t bn; 851 int blsize; 852 u_long boff; 853 854 boff = diroffset & ~pmp->pm_crbomask; 855 blsize = pmp->pm_bpcluster; 856 if (dirclust == MSDOSFSROOT 857 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 858 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 859 bn = detobn(pmp, dirclust, diroffset); 860 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 861 brelse(*bpp); 862 *bpp = NULL; 863 return (error); 864 } 865 if (epp) 866 *epp = bptoep(pmp, *bpp, diroffset); 867 return (0); 868} 869 870/* 871 * Read in the disk block containing the directory entry dep came from and 872 * return the address of the buf header, and the address of the directory 873 * entry within the block. 874 */ 875int 876readde(dep, bpp, epp) 877 struct denode *dep; 878 struct buf **bpp; 879 struct direntry **epp; 880{ 881 882 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 883 bpp, epp)); 884} 885 886/* 887 * Remove a directory entry. At this point the file represented by the 888 * directory entry to be removed is still full length until noone has it 889 * open. When the file no longer being used msdosfs_inactive() is called 890 * and will truncate the file to 0 length. When the vnode containing the 891 * denode is needed for some other purpose by VFS it will call 892 * msdosfs_reclaim() which will remove the denode from the denode cache. 893 */ 894int 895removede(pdep, dep) 896 struct denode *pdep; /* directory where the entry is removed */ 897 struct denode *dep; /* file to be removed */ 898{ 899 int error; 900 struct direntry *ep; 901 struct buf *bp; 902 daddr_t bn; 903 int blsize; 904 struct msdosfsmount *pmp = pdep->de_pmp; 905 u_long offset = pdep->de_fndoffset; 906 907#ifdef MSDOSFS_DEBUG 908 printf("removede(): filename %s, dep %p, offset %08lx\n", 909 dep->de_Name, dep, offset); 910#endif 911 912 dep->de_refcnt--; 913 offset += sizeof(struct direntry); 914 do { 915 offset -= sizeof(struct direntry); 916 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 917 if (error) 918 return error; 919 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 920 if (error) { 921 brelse(bp); 922 return error; 923 } 924 ep = bptoep(pmp, bp, offset); 925 /* 926 * Check whether, if we came here the second time, i.e. 927 * when underflowing into the previous block, the last 928 * entry in this block is a longfilename entry, too. 929 */ 930 if (ep->deAttributes != ATTR_WIN95 931 && offset != pdep->de_fndoffset) { 932 brelse(bp); 933 break; 934 } 935 offset += sizeof(struct direntry); 936 while (1) { 937 /* 938 * We are a bit agressive here in that we delete any Win95 939 * entries preceding this entry, not just the ones we "own". 940 * Since these presumably aren't valid anyway, 941 * there should be no harm. 942 */ 943 offset -= sizeof(struct direntry); 944 ep--->deName[0] = SLOT_DELETED; 945 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 946 || !(offset & pmp->pm_crbomask) 947 || ep->deAttributes != ATTR_WIN95) 948 break; 949 } 950 if ((error = bwrite(bp)) != 0) 951 return error; 952 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 953 && !(offset & pmp->pm_crbomask) 954 && offset); 955 return 0; 956} 957 958/* 959 * Create a unique DOS name in dvp 960 */ 961int 962uniqdosname(dep, cnp, cp) 963 struct denode *dep; 964 struct componentname *cnp; 965 u_char *cp; 966{ 967 struct msdosfsmount *pmp = dep->de_pmp; 968 struct direntry *dentp; 969 int gen; 970 int blsize; 971 u_long cn; 972 daddr_t bn; 973 struct buf *bp; 974 int error; 975 976 for (gen = 1;; gen++) { 977 /* 978 * Generate DOS name with generation number 979 */ 980 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 981 cnp->cn_namelen, gen)) 982 return gen == 1 ? EINVAL : EEXIST; 983 984 /* 985 * Now look for a dir entry with this exact name 986 */ 987 for (cn = error = 0; !error; cn++) { 988 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 989 if (error == E2BIG) /* EOF reached and not found */ 990 return 0; 991 return error; 992 } 993 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 994 if (error) { 995 brelse(bp); 996 return error; 997 } 998 for (dentp = (struct direntry *)bp->b_data; 999 (char *)dentp < bp->b_data + blsize; 1000 dentp++) { 1001 if (dentp->deName[0] == SLOT_EMPTY) { 1002 /* 1003 * Last used entry and not found 1004 */ 1005 brelse(bp); 1006 return 0; 1007 } 1008 /* 1009 * Ignore volume labels and Win95 entries 1010 */ 1011 if (dentp->deAttributes & ATTR_VOLUME) 1012 continue; 1013 if (!bcmp(dentp->deName, cp, 11)) { 1014 error = EEXIST; 1015 break; 1016 } 1017 } 1018 brelse(bp); 1019 } 1020 } 1021} 1022 1023/* 1024 * Find any Win'95 long filename entry in directory dep 1025 */ 1026int 1027findwin95(dep) 1028 struct denode *dep; 1029{ 1030 struct msdosfsmount *pmp = dep->de_pmp; 1031 struct direntry *dentp; 1032 int blsize; 1033 u_long cn; 1034 daddr_t bn; 1035 struct buf *bp; 1036 1037 /* 1038 * Read through the directory looking for Win'95 entries 1039 * Note: Error currently handled just as EOF XXX 1040 */ 1041 for (cn = 0;; cn++) { 1042 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1043 return 0; 1044 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1045 brelse(bp); 1046 return 0; 1047 } 1048 for (dentp = (struct direntry *)bp->b_data; 1049 (char *)dentp < bp->b_data + blsize; 1050 dentp++) { 1051 if (dentp->deName[0] == SLOT_EMPTY) { 1052 /* 1053 * Last used entry and not found 1054 */ 1055 brelse(bp); 1056 return 0; 1057 } 1058 if (dentp->deName[0] == SLOT_DELETED) { 1059 /* 1060 * Ignore deleted files 1061 * Note: might be an indication of Win'95 anyway XXX 1062 */ 1063 continue; 1064 } 1065 if (dentp->deAttributes == ATTR_WIN95) { 1066 brelse(bp); 1067 return 1; 1068 } 1069 } 1070 brelse(bp); 1071 } 1072} 1073