msdosfs_lookup.c revision 35871
1/* $Id: msdosfs_lookup.c,v 1.22 1998/02/26 06:45:44 msmith 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 int unlen; 118 119 int wincnt = 1; 120 int chksum = -1; 121 int olddos = 1; 122 123#ifdef MSDOSFS_DEBUG 124 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr); 125#endif 126 dp = VTODE(vdp); 127 pmp = dp->de_pmp; 128 *vpp = NULL; 129 lockparent = flags & LOCKPARENT; 130 wantparent = flags & (LOCKPARENT | WANTPARENT); 131#ifdef MSDOSFS_DEBUG 132 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n", 133 vdp, dp, dp->de_Attributes); 134#endif 135 136 /* 137 * If they are going after the . or .. entry in the root directory, 138 * they won't find it. DOS filesystems don't have them in the root 139 * directory. So, we fake it. deget() is in on this scam too. 140 */ 141 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' && 142 (cnp->cn_namelen == 1 || 143 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) { 144 isadir = ATTR_DIRECTORY; 145 scn = MSDOSFSROOT; 146#ifdef MSDOSFS_DEBUG 147 printf("msdosfs_lookup(): looking for . or .. in root directory\n"); 148#endif 149 cluster = MSDOSFSROOT; 150 blkoff = MSDOSFSROOT_OFS; 151 goto foundroot; 152 } 153 154 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 155 cnp->cn_namelen, 0, 156 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 157 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) { 158 case 0: 159 return (EINVAL); 160 case 1: 161 break; 162 case 2: 163 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 164 cnp->cn_namelen) + 1; 165 break; 166 case 3: 167 olddos = 0; 168 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 169 cnp->cn_namelen) + 1; 170 break; 171 } 172 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 173 wincnt = 1; 174 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen); 175 176 /* 177 * Suppress search for slots unless creating 178 * file and at end of pathname, in which case 179 * we watch for a place to put the new file in 180 * case it doesn't already exist. 181 */ 182 slotcount = wincnt; 183 if ((nameiop == CREATE || nameiop == RENAME) && 184 (flags & ISLASTCN)) 185 slotcount = 0; 186 187#ifdef MSDOSFS_DEBUG 188 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n", 189 dosfilename, cnp->cn_namelen); 190#endif 191 /* 192 * Search the directory pointed at by vdp for the name pointed at 193 * by cnp->cn_nameptr. 194 */ 195 tdp = NULL; 196 /* 197 * The outer loop ranges over the clusters that make up the 198 * directory. Note that the root directory is different from all 199 * other directories. It has a fixed number of blocks that are not 200 * part of the pool of allocatable clusters. So, we treat it a 201 * little differently. The root directory starts at "cluster" 0. 202 */ 203 diroff = 0; 204 for (frcn = 0;; frcn++) { 205 error = pcbmap(dp, frcn, &bn, &cluster, &blsize); 206 if (error) { 207 if (error == E2BIG) 208 break; 209 return (error); 210 } 211 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 212 if (error) { 213 brelse(bp); 214 return (error); 215 } 216 for (blkoff = 0; blkoff < blsize; 217 blkoff += sizeof(struct direntry), 218 diroff += sizeof(struct direntry)) { 219 dep = (struct direntry *)(bp->b_data + blkoff); 220 /* 221 * If the slot is empty and we are still looking 222 * for an empty then remember this one. If the 223 * slot is not empty then check to see if it 224 * matches what we are looking for. If the slot 225 * has never been filled with anything, then the 226 * remainder of the directory has never been used, 227 * so there is no point in searching it. 228 */ 229 if (dep->deName[0] == SLOT_EMPTY || 230 dep->deName[0] == SLOT_DELETED) { 231 /* 232 * Drop memory of previous long matches 233 */ 234 chksum = -1; 235 236 if (slotcount < wincnt) { 237 slotcount++; 238 slotoffset = diroff; 239 } 240 if (dep->deName[0] == SLOT_EMPTY) { 241 brelse(bp); 242 goto notfound; 243 } 244 } else { 245 /* 246 * If there wasn't enough space for our winentries, 247 * forget about the empty space 248 */ 249 if (slotcount < wincnt) 250 slotcount = 0; 251 252 /* 253 * Check for Win95 long filename entry 254 */ 255 if (dep->deAttributes == ATTR_WIN95) { 256 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 257 continue; 258 259 chksum = winChkName((const u_char *)cnp->cn_nameptr, 260 unlen, 261 (struct winentry *)dep, 262 chksum, 263 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 264 pmp->pm_u2w, 265 pmp->pm_flags & MSDOSFSMNT_ULTABLE, 266 pmp->pm_ul); 267 continue; 268 } 269 270 /* 271 * Ignore volume labels (anywhere, not just 272 * the root directory). 273 */ 274 if (dep->deAttributes & ATTR_VOLUME) { 275 chksum = -1; 276 continue; 277 } 278 279 /* 280 * Check for a checksum or name match 281 */ 282 if (chksum != winChksum(dep->deName) 283 && (!olddos || bcmp(dosfilename, dep->deName, 11))) { 284 chksum = -1; 285 continue; 286 } 287#ifdef MSDOSFS_DEBUG 288 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 289 blkoff, diroff); 290#endif 291 /* 292 * Remember where this directory 293 * entry came from for whoever did 294 * this lookup. 295 */ 296 dp->de_fndoffset = diroff; 297 dp->de_fndcnt = wincnt - 1; 298 299 goto found; 300 } 301 } /* for (blkoff = 0; .... */ 302 /* 303 * Release the buffer holding the directory cluster just 304 * searched. 305 */ 306 brelse(bp); 307 } /* for (frcn = 0; ; frcn++) */ 308 309notfound: 310 /* 311 * We hold no disk buffers at this point. 312 */ 313 314 /* 315 * Fixup the slot description to point to the place where 316 * we might put the new DOS direntry (putting the Win95 317 * long name entries before that) 318 */ 319 if (!slotcount) { 320 slotcount = 1; 321 slotoffset = diroff; 322 } 323 if (wincnt > slotcount) 324 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 325 326 /* 327 * If we get here we didn't find the entry we were looking for. But 328 * that's ok if we are creating or renaming and are at the end of 329 * the pathname and the directory hasn't been removed. 330 */ 331#ifdef MSDOSFS_DEBUG 332 printf("msdosfs_lookup(): op %d, refcnt %ld\n", 333 nameiop, dp->de_refcnt); 334 printf(" slotcount %d, slotoffset %d\n", 335 slotcount, slotoffset); 336#endif 337 if ((nameiop == CREATE || nameiop == RENAME) && 338 (flags & ISLASTCN) && dp->de_refcnt != 0) { 339 /* 340 * Access for write is interpreted as allowing 341 * creation of files in the directory. 342 */ 343 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 344 if (error) 345 return (error); 346 /* 347 * Return an indication of where the new directory 348 * entry should be put. 349 */ 350 dp->de_fndoffset = slotoffset; 351 dp->de_fndcnt = wincnt - 1; 352 353 /* 354 * We return with the directory locked, so that 355 * the parameters we set up above will still be 356 * valid if we actually decide to do a direnter(). 357 * We return ni_vp == NULL to indicate that the entry 358 * does not currently exist; we leave a pointer to 359 * the (locked) directory inode in ndp->ni_dvp. 360 * The pathname buffer is saved so that the name 361 * can be obtained later. 362 * 363 * NB - if the directory is unlocked, then this 364 * information cannot be used. 365 */ 366 cnp->cn_flags |= SAVENAME; 367 if (!lockparent) 368 VOP_UNLOCK(vdp, 0, p); 369 return (EJUSTRETURN); 370 } 371 /* 372 * Insert name into cache (as non-existent) if appropriate. 373 */ 374 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 375 cache_enter(vdp, *vpp, cnp); 376 return (ENOENT); 377 378found: 379 /* 380 * NOTE: We still have the buffer with matched directory entry at 381 * this point. 382 */ 383 isadir = dep->deAttributes & ATTR_DIRECTORY; 384 scn = getushort(dep->deStartCluster); 385 if (FAT32(pmp)) { 386 scn |= getushort(dep->deHighClust) << 16; 387 if (scn == pmp->pm_rootdirblk) { 388 /* 389 * There should actually be 0 here. 390 * Just ignore the error. 391 */ 392 scn = MSDOSFSROOT; 393 } 394 } 395 396 if (isadir) { 397 cluster = scn; 398 if (cluster == MSDOSFSROOT) 399 blkoff = MSDOSFSROOT_OFS; 400 else 401 blkoff = 0; 402 } else if (cluster == MSDOSFSROOT) 403 blkoff = diroff; 404 405 /* 406 * Now release buf to allow deget to read the entry again. 407 * Reserving it here and giving it to deget could result 408 * in a deadlock. 409 */ 410 brelse(bp); 411 bp = 0; 412 413foundroot: 414 /* 415 * If we entered at foundroot, then we are looking for the . or .. 416 * entry of the filesystems root directory. isadir and scn were 417 * setup before jumping here. And, bp is already null. 418 */ 419 if (FAT32(pmp) && scn == MSDOSFSROOT) 420 scn = pmp->pm_rootdirblk; 421 422 /* 423 * If deleting, and at end of pathname, return 424 * parameters which can be used to remove file. 425 * If the wantparent flag isn't set, we return only 426 * the directory (in ndp->ni_dvp), otherwise we go 427 * on and lock the inode, being careful with ".". 428 */ 429 if (nameiop == DELETE && (flags & ISLASTCN)) { 430 /* 431 * Don't allow deleting the root. 432 */ 433 if (blkoff == MSDOSFSROOT_OFS) 434 return EROFS; /* really? XXX */ 435 436 /* 437 * Write access to directory required to delete files. 438 */ 439 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 440 if (error) 441 return (error); 442 443 /* 444 * Return pointer to current entry in dp->i_offset. 445 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 446 */ 447 if (dp->de_StartCluster == scn && isadir) { /* "." */ 448 VREF(vdp); 449 *vpp = vdp; 450 return (0); 451 } 452 error = deget(pmp, cluster, blkoff, &tdp); 453 if (error) 454 return (error); 455 *vpp = DETOV(tdp); 456 if (!lockparent) 457 VOP_UNLOCK(vdp, 0, p); 458 return (0); 459 } 460 461 /* 462 * If rewriting (RENAME), return the inode and the 463 * information required to rewrite the present directory 464 * Must get inode of directory entry to verify it's a 465 * regular file, or empty directory. 466 */ 467 if (nameiop == RENAME && wantparent && 468 (flags & ISLASTCN)) { 469 if (blkoff == MSDOSFSROOT_OFS) 470 return EROFS; /* really? XXX */ 471 472 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 473 if (error) 474 return (error); 475 476 /* 477 * Careful about locking second inode. 478 * This can only occur if the target is ".". 479 */ 480 if (dp->de_StartCluster == scn && isadir) 481 return (EISDIR); 482 483 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 484 return (error); 485 *vpp = DETOV(tdp); 486 cnp->cn_flags |= SAVENAME; 487 if (!lockparent) 488 VOP_UNLOCK(vdp, 0, p); 489 return (0); 490 } 491 492 /* 493 * Step through the translation in the name. We do not `vput' the 494 * directory because we may need it again if a symbolic link 495 * is relative to the current directory. Instead we save it 496 * unlocked as "pdp". We must get the target inode before unlocking 497 * the directory to insure that the inode will not be removed 498 * before we get it. We prevent deadlock by always fetching 499 * inodes from the root, moving down the directory tree. Thus 500 * when following backward pointers ".." we must unlock the 501 * parent directory before getting the requested directory. 502 * There is a potential race condition here if both the current 503 * and parent directories are removed before the VFS_VGET for the 504 * inode associated with ".." returns. We hope that this occurs 505 * infrequently since we cannot avoid this race condition without 506 * implementing a sophisticated deadlock detection algorithm. 507 * Note also that this simple deadlock detection scheme will not 508 * work if the file system has any hard links other than ".." 509 * that point backwards in the directory structure. 510 */ 511 pdp = vdp; 512 if (flags & ISDOTDOT) { 513 VOP_UNLOCK(pdp, 0, p); 514 error = deget(pmp, cluster, blkoff, &tdp); 515 if (error) { 516 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 517 return (error); 518 } 519 if (lockparent && (flags & ISLASTCN) && 520 (error = vn_lock(pdp, LK_EXCLUSIVE, p))) { 521 vput(DETOV(tdp)); 522 return (error); 523 } 524 *vpp = DETOV(tdp); 525 } else if (dp->de_StartCluster == scn && isadir) { 526 VREF(vdp); /* we want ourself, ie "." */ 527 *vpp = vdp; 528 } else { 529 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 530 return (error); 531 if (!lockparent || !(flags & ISLASTCN)) 532 VOP_UNLOCK(pdp, 0, p); 533 *vpp = DETOV(tdp); 534 } 535 536 /* 537 * Insert name into cache if appropriate. 538 */ 539 if (cnp->cn_flags & MAKEENTRY) 540 cache_enter(vdp, *vpp, cnp); 541 return (0); 542} 543 544/* 545 * dep - directory entry to copy into the directory 546 * ddep - directory to add to 547 * depp - return the address of the denode for the created directory entry 548 * if depp != 0 549 * cnp - componentname needed for Win95 long filenames 550 */ 551int 552createde(dep, ddep, depp, cnp) 553 struct denode *dep; 554 struct denode *ddep; 555 struct denode **depp; 556 struct componentname *cnp; 557{ 558 int error; 559 u_long dirclust, diroffset; 560 struct direntry *ndep; 561 struct msdosfsmount *pmp = ddep->de_pmp; 562 struct buf *bp; 563 daddr_t bn; 564 int blsize; 565 566#ifdef MSDOSFS_DEBUG 567 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 568 dep, ddep, depp, cnp); 569#endif 570 571 /* 572 * If no space left in the directory then allocate another cluster 573 * and chain it onto the end of the file. There is one exception 574 * to this. That is, if the root directory has no more space it 575 * can NOT be expanded. extendfile() checks for and fails attempts 576 * to extend the root directory. We just return an error in that 577 * case. 578 */ 579 if (ddep->de_fndoffset >= ddep->de_FileSize) { 580 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 581 - ddep->de_FileSize; 582 dirclust = de_clcount(pmp, diroffset); 583 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 584 if (error) { 585 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL); 586 return error; 587 } 588 589 /* 590 * Update the size of the directory 591 */ 592 ddep->de_FileSize += de_cn2off(pmp, dirclust); 593 } 594 595 /* 596 * We just read in the cluster with space. Copy the new directory 597 * entry in. Then write it to disk. NOTE: DOS directories 598 * do not get smaller as clusters are emptied. 599 */ 600 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 601 &bn, &dirclust, &blsize); 602 if (error) 603 return error; 604 diroffset = ddep->de_fndoffset; 605 if (dirclust != MSDOSFSROOT) 606 diroffset &= pmp->pm_crbomask; 607 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 608 brelse(bp); 609 return error; 610 } 611 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 612 613 DE_EXTERNALIZE(ndep, dep); 614 615 /* 616 * Now write the Win95 long name 617 */ 618 if (ddep->de_fndcnt > 0) { 619 u_int8_t chksum = winChksum(ndep->deName); 620 const u_char *un = (const u_char *)cnp->cn_nameptr; 621 int unlen = cnp->cn_namelen; 622 int cnt = 1; 623 624 while (--ddep->de_fndcnt >= 0) { 625 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 626 if ((error = bwrite(bp)) != 0) 627 return error; 628 629 ddep->de_fndoffset -= sizeof(struct direntry); 630 error = pcbmap(ddep, 631 de_cluster(pmp, 632 ddep->de_fndoffset), 633 &bn, 0, &blsize); 634 if (error) 635 return error; 636 637 error = bread(pmp->pm_devvp, bn, blsize, 638 NOCRED, &bp); 639 if (error) { 640 brelse(bp); 641 return error; 642 } 643 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 644 } else { 645 ndep--; 646 ddep->de_fndoffset -= sizeof(struct direntry); 647 } 648 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 649 cnt++, chksum, 650 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 651 pmp->pm_u2w)) 652 break; 653 } 654 } 655 656 if ((error = bwrite(bp)) != 0) 657 return error; 658 659 /* 660 * If they want us to return with the denode gotten. 661 */ 662 if (depp) { 663 if (dep->de_Attributes & ATTR_DIRECTORY) { 664 dirclust = dep->de_StartCluster; 665 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 666 dirclust = MSDOSFSROOT; 667 if (dirclust == MSDOSFSROOT) 668 diroffset = MSDOSFSROOT_OFS; 669 else 670 diroffset = 0; 671 } 672 return deget(pmp, dirclust, diroffset, depp); 673 } 674 675 return 0; 676} 677 678/* 679 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 680 * return 0 if not empty or error. 681 */ 682int 683dosdirempty(dep) 684 struct denode *dep; 685{ 686 int blsize; 687 int error; 688 u_long cn; 689 daddr_t bn; 690 struct buf *bp; 691 struct msdosfsmount *pmp = dep->de_pmp; 692 struct direntry *dentp; 693 694 /* 695 * Since the filesize field in directory entries for a directory is 696 * zero, we just have to feel our way through the directory until 697 * we hit end of file. 698 */ 699 for (cn = 0;; cn++) { 700 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 701 if (error == E2BIG) 702 return (1); /* it's empty */ 703 return (0); 704 } 705 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 706 if (error) { 707 brelse(bp); 708 return (0); 709 } 710 for (dentp = (struct direntry *)bp->b_data; 711 (char *)dentp < bp->b_data + blsize; 712 dentp++) { 713 if (dentp->deName[0] != SLOT_DELETED && 714 (dentp->deAttributes & ATTR_VOLUME) == 0) { 715 /* 716 * In dos directories an entry whose name 717 * starts with SLOT_EMPTY (0) starts the 718 * beginning of the unused part of the 719 * directory, so we can just return that it 720 * is empty. 721 */ 722 if (dentp->deName[0] == SLOT_EMPTY) { 723 brelse(bp); 724 return (1); 725 } 726 /* 727 * Any names other than "." and ".." in a 728 * directory mean it is not empty. 729 */ 730 if (bcmp(dentp->deName, ". ", 11) && 731 bcmp(dentp->deName, ".. ", 11)) { 732 brelse(bp); 733#ifdef MSDOSFS_DEBUG 734 printf("dosdirempty(): entry found %02x, %02x\n", 735 dentp->deName[0], dentp->deName[1]); 736#endif 737 return (0); /* not empty */ 738 } 739 } 740 } 741 brelse(bp); 742 } 743 /* NOTREACHED */ 744} 745 746/* 747 * Check to see if the directory described by target is in some 748 * subdirectory of source. This prevents something like the following from 749 * succeeding and leaving a bunch or files and directories orphaned. mv 750 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 751 * 752 * source - the inode for /a/b/c 753 * target - the inode for /a/b/c/d/e/f 754 * 755 * Returns 0 if target is NOT a subdirectory of source. 756 * Otherwise returns a non-zero error number. 757 * The target inode is always unlocked on return. 758 */ 759int 760doscheckpath(source, target) 761 struct denode *source; 762 struct denode *target; 763{ 764 daddr_t scn; 765 struct msdosfsmount *pmp; 766 struct direntry *ep; 767 struct denode *dep; 768 struct buf *bp = NULL; 769 int error = 0; 770 771 dep = target; 772 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 773 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 774 error = ENOTDIR; 775 goto out; 776 } 777 if (dep->de_StartCluster == source->de_StartCluster) { 778 error = EEXIST; 779 goto out; 780 } 781 if (dep->de_StartCluster == MSDOSFSROOT) 782 goto out; 783 pmp = dep->de_pmp; 784#ifdef DIAGNOSTIC 785 if (pmp != source->de_pmp) 786 panic("doscheckpath: source and target on different filesystems"); 787#endif 788 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 789 goto out; 790 791 for (;;) { 792 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 793 error = ENOTDIR; 794 break; 795 } 796 scn = dep->de_StartCluster; 797 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 798 pmp->pm_bpcluster, NOCRED, &bp); 799 if (error) 800 break; 801 802 ep = (struct direntry *) bp->b_data + 1; 803 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 804 bcmp(ep->deName, ".. ", 11) != 0) { 805 error = ENOTDIR; 806 break; 807 } 808 scn = getushort(ep->deStartCluster); 809 if (FAT32(pmp)) 810 scn |= getushort(ep->deHighClust) << 16; 811 812 if (scn == source->de_StartCluster) { 813 error = EINVAL; 814 break; 815 } 816 if (scn == MSDOSFSROOT) 817 break; 818 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 819 /* 820 * scn should be 0 in this case, 821 * but we silently ignore the error. 822 */ 823 break; 824 } 825 826 vput(DETOV(dep)); 827 brelse(bp); 828 bp = NULL; 829 /* NOTE: deget() clears dep on error */ 830 if ((error = deget(pmp, scn, 0, &dep)) != 0) 831 break; 832 } 833out:; 834 if (bp) 835 brelse(bp); 836 if (error == ENOTDIR) 837 printf("doscheckpath(): .. not a directory?\n"); 838 if (dep != NULL) 839 vput(DETOV(dep)); 840 return (error); 841} 842 843/* 844 * Read in the disk block containing the directory entry (dirclu, dirofs) 845 * and return the address of the buf header, and the address of the 846 * directory entry within the block. 847 */ 848int 849readep(pmp, dirclust, diroffset, bpp, epp) 850 struct msdosfsmount *pmp; 851 u_long dirclust, diroffset; 852 struct buf **bpp; 853 struct direntry **epp; 854{ 855 int error; 856 daddr_t bn; 857 int blsize; 858 u_long boff; 859 860 boff = diroffset & ~pmp->pm_crbomask; 861 blsize = pmp->pm_bpcluster; 862 if (dirclust == MSDOSFSROOT 863 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 864 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 865 bn = detobn(pmp, dirclust, diroffset); 866 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 867 brelse(*bpp); 868 *bpp = NULL; 869 return (error); 870 } 871 if (epp) 872 *epp = bptoep(pmp, *bpp, diroffset); 873 return (0); 874} 875 876/* 877 * Read in the disk block containing the directory entry dep came from and 878 * return the address of the buf header, and the address of the directory 879 * entry within the block. 880 */ 881int 882readde(dep, bpp, epp) 883 struct denode *dep; 884 struct buf **bpp; 885 struct direntry **epp; 886{ 887 888 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 889 bpp, epp)); 890} 891 892/* 893 * Remove a directory entry. At this point the file represented by the 894 * directory entry to be removed is still full length until noone has it 895 * open. When the file no longer being used msdosfs_inactive() is called 896 * and will truncate the file to 0 length. When the vnode containing the 897 * denode is needed for some other purpose by VFS it will call 898 * msdosfs_reclaim() which will remove the denode from the denode cache. 899 */ 900int 901removede(pdep, dep) 902 struct denode *pdep; /* directory where the entry is removed */ 903 struct denode *dep; /* file to be removed */ 904{ 905 int error; 906 struct direntry *ep; 907 struct buf *bp; 908 daddr_t bn; 909 int blsize; 910 struct msdosfsmount *pmp = pdep->de_pmp; 911 u_long offset = pdep->de_fndoffset; 912 913#ifdef MSDOSFS_DEBUG 914 printf("removede(): filename %s, dep %p, offset %08lx\n", 915 dep->de_Name, dep, offset); 916#endif 917 918 dep->de_refcnt--; 919 offset += sizeof(struct direntry); 920 do { 921 offset -= sizeof(struct direntry); 922 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 923 if (error) 924 return error; 925 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 926 if (error) { 927 brelse(bp); 928 return error; 929 } 930 ep = bptoep(pmp, bp, offset); 931 /* 932 * Check whether, if we came here the second time, i.e. 933 * when underflowing into the previous block, the last 934 * entry in this block is a longfilename entry, too. 935 */ 936 if (ep->deAttributes != ATTR_WIN95 937 && offset != pdep->de_fndoffset) { 938 brelse(bp); 939 break; 940 } 941 offset += sizeof(struct direntry); 942 while (1) { 943 /* 944 * We are a bit agressive here in that we delete any Win95 945 * entries preceding this entry, not just the ones we "own". 946 * Since these presumably aren't valid anyway, 947 * there should be no harm. 948 */ 949 offset -= sizeof(struct direntry); 950 ep--->deName[0] = SLOT_DELETED; 951 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 952 || !(offset & pmp->pm_crbomask) 953 || ep->deAttributes != ATTR_WIN95) 954 break; 955 } 956 if ((error = bwrite(bp)) != 0) 957 return error; 958 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 959 && !(offset & pmp->pm_crbomask) 960 && offset); 961 return 0; 962} 963 964/* 965 * Create a unique DOS name in dvp 966 */ 967int 968uniqdosname(dep, cnp, cp) 969 struct denode *dep; 970 struct componentname *cnp; 971 u_char *cp; 972{ 973 struct msdosfsmount *pmp = dep->de_pmp; 974 struct direntry *dentp; 975 int gen; 976 int blsize; 977 u_long cn; 978 daddr_t bn; 979 struct buf *bp; 980 int error; 981 982 for (gen = 1;; gen++) { 983 /* 984 * Generate DOS name with generation number 985 */ 986 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 987 cnp->cn_namelen, gen, 988 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 989 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) 990 return gen == 1 ? EINVAL : EEXIST; 991 992 /* 993 * Now look for a dir entry with this exact name 994 */ 995 for (cn = error = 0; !error; cn++) { 996 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 997 if (error == E2BIG) /* EOF reached and not found */ 998 return 0; 999 return error; 1000 } 1001 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 1002 if (error) { 1003 brelse(bp); 1004 return error; 1005 } 1006 for (dentp = (struct direntry *)bp->b_data; 1007 (char *)dentp < bp->b_data + blsize; 1008 dentp++) { 1009 if (dentp->deName[0] == SLOT_EMPTY) { 1010 /* 1011 * Last used entry and not found 1012 */ 1013 brelse(bp); 1014 return 0; 1015 } 1016 /* 1017 * Ignore volume labels and Win95 entries 1018 */ 1019 if (dentp->deAttributes & ATTR_VOLUME) 1020 continue; 1021 if (!bcmp(dentp->deName, cp, 11)) { 1022 error = EEXIST; 1023 break; 1024 } 1025 } 1026 brelse(bp); 1027 } 1028 } 1029} 1030 1031/* 1032 * Find any Win'95 long filename entry in directory dep 1033 */ 1034int 1035findwin95(dep) 1036 struct denode *dep; 1037{ 1038 struct msdosfsmount *pmp = dep->de_pmp; 1039 struct direntry *dentp; 1040 int blsize; 1041 u_long cn; 1042 daddr_t bn; 1043 struct buf *bp; 1044 1045 /* 1046 * Read through the directory looking for Win'95 entries 1047 * Note: Error currently handled just as EOF XXX 1048 */ 1049 for (cn = 0;; cn++) { 1050 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1051 return 0; 1052 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1053 brelse(bp); 1054 return 0; 1055 } 1056 for (dentp = (struct direntry *)bp->b_data; 1057 (char *)dentp < bp->b_data + blsize; 1058 dentp++) { 1059 if (dentp->deName[0] == SLOT_EMPTY) { 1060 /* 1061 * Last used entry and not found 1062 */ 1063 brelse(bp); 1064 return 0; 1065 } 1066 if (dentp->deName[0] == SLOT_DELETED) { 1067 /* 1068 * Ignore deleted files 1069 * Note: might be an indication of Win'95 anyway XXX 1070 */ 1071 continue; 1072 } 1073 if (dentp->deAttributes == ATTR_WIN95) { 1074 brelse(bp); 1075 return 1; 1076 } 1077 } 1078 brelse(bp); 1079 } 1080} 1081