msdosfs_lookup.c revision 33760
1/* $Id: msdosfs_lookup.c,v 1.18 1998/02/22 18:00:52 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 (pmp->pm_flags & MSDOSFSMNT_ULTABLE) ? 262 pmp->pm_ul : NULL); 263 continue; 264 } 265 266 /* 267 * Ignore volume labels (anywhere, not just 268 * the root directory). 269 */ 270 if (dep->deAttributes & ATTR_VOLUME) { 271 chksum = -1; 272 continue; 273 } 274 275 /* 276 * Check for a checksum or name match 277 */ 278 if (chksum != winChksum(dep->deName) 279 && (!olddos || bcmp(dosfilename, dep->deName, 11))) { 280 chksum = -1; 281 continue; 282 } 283#ifdef MSDOSFS_DEBUG 284 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 285 blkoff, diroff); 286#endif 287 /* 288 * Remember where this directory 289 * entry came from for whoever did 290 * this lookup. 291 */ 292 dp->de_fndoffset = diroff; 293 dp->de_fndcnt = 0; /* unused anyway */ 294 295 goto found; 296 } 297 } /* for (blkoff = 0; .... */ 298 /* 299 * Release the buffer holding the directory cluster just 300 * searched. 301 */ 302 brelse(bp); 303 } /* for (frcn = 0; ; frcn++) */ 304 305notfound: 306 /* 307 * We hold no disk buffers at this point. 308 */ 309 310 /* 311 * Fixup the slot description to point to the place where 312 * we might put the new DOS direntry (putting the Win95 313 * long name entries before that) 314 */ 315 if (!slotcount) { 316 slotcount = 1; 317 slotoffset = diroff; 318 } 319 if (wincnt > slotcount) 320 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 321 322 /* 323 * If we get here we didn't find the entry we were looking for. But 324 * that's ok if we are creating or renaming and are at the end of 325 * the pathname and the directory hasn't been removed. 326 */ 327#ifdef MSDOSFS_DEBUG 328 printf("msdosfs_lookup(): op %d, refcnt %ld\n", 329 nameiop, dp->de_refcnt); 330 printf(" slotcount %d, slotoffset %d\n", 331 slotcount, slotoffset); 332#endif 333 if ((nameiop == CREATE || nameiop == RENAME) && 334 (flags & ISLASTCN) && dp->de_refcnt != 0) { 335 /* 336 * Access for write is interpreted as allowing 337 * creation of files in the directory. 338 */ 339 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 340 if (error) 341 return (error); 342 /* 343 * Return an indication of where the new directory 344 * entry should be put. 345 */ 346 dp->de_fndoffset = slotoffset; 347 dp->de_fndcnt = wincnt - 1; 348 349 /* 350 * We return with the directory locked, so that 351 * the parameters we set up above will still be 352 * valid if we actually decide to do a direnter(). 353 * We return ni_vp == NULL to indicate that the entry 354 * does not currently exist; we leave a pointer to 355 * the (locked) directory inode in ndp->ni_dvp. 356 * The pathname buffer is saved so that the name 357 * can be obtained later. 358 * 359 * NB - if the directory is unlocked, then this 360 * information cannot be used. 361 */ 362 cnp->cn_flags |= SAVENAME; 363 if (!lockparent) 364 VOP_UNLOCK(vdp, 0, p); 365 return (EJUSTRETURN); 366 } 367 /* 368 * Insert name into cache (as non-existent) if appropriate. 369 */ 370 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 371 cache_enter(vdp, *vpp, cnp); 372 return (ENOENT); 373 374found: 375 /* 376 * NOTE: We still have the buffer with matched directory entry at 377 * this point. 378 */ 379 isadir = dep->deAttributes & ATTR_DIRECTORY; 380 scn = getushort(dep->deStartCluster); 381 if (FAT32(pmp)) { 382 scn |= getushort(dep->deHighClust) << 16; 383 if (scn == pmp->pm_rootdirblk) { 384 /* 385 * There should actually be 0 here. 386 * Just ignore the error. 387 */ 388 scn = MSDOSFSROOT; 389 } 390 } 391 392 if (isadir) { 393 cluster = scn; 394 if (cluster == MSDOSFSROOT) 395 blkoff = MSDOSFSROOT_OFS; 396 else 397 blkoff = 0; 398 } else if (cluster == MSDOSFSROOT) 399 blkoff = diroff; 400 401 /* 402 * Now release buf to allow deget to read the entry again. 403 * Reserving it here and giving it to deget could result 404 * in a deadlock. 405 */ 406 brelse(bp); 407 bp = 0; 408 409foundroot: 410 /* 411 * If we entered at foundroot, then we are looking for the . or .. 412 * entry of the filesystems root directory. isadir and scn were 413 * setup before jumping here. And, bp is already null. 414 */ 415 if (FAT32(pmp) && scn == MSDOSFSROOT) 416 scn = pmp->pm_rootdirblk; 417 418 /* 419 * If deleting, and at end of pathname, return 420 * parameters which can be used to remove file. 421 * If the wantparent flag isn't set, we return only 422 * the directory (in ndp->ni_dvp), otherwise we go 423 * on and lock the inode, being careful with ".". 424 */ 425 if (nameiop == DELETE && (flags & ISLASTCN)) { 426 /* 427 * Don't allow deleting the root. 428 */ 429 if (blkoff == MSDOSFSROOT_OFS) 430 return EROFS; /* really? XXX */ 431 432 /* 433 * Write access to directory required to delete files. 434 */ 435 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 436 if (error) 437 return (error); 438 439 /* 440 * Return pointer to current entry in dp->i_offset. 441 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 442 */ 443 if (dp->de_StartCluster == scn && isadir) { /* "." */ 444 VREF(vdp); 445 *vpp = vdp; 446 return (0); 447 } 448 error = deget(pmp, cluster, blkoff, &tdp); 449 if (error) 450 return (error); 451 *vpp = DETOV(tdp); 452 if (!lockparent) 453 VOP_UNLOCK(vdp, 0, p); 454 return (0); 455 } 456 457 /* 458 * If rewriting (RENAME), return the inode and the 459 * information required to rewrite the present directory 460 * Must get inode of directory entry to verify it's a 461 * regular file, or empty directory. 462 */ 463 if (nameiop == RENAME && wantparent && 464 (flags & ISLASTCN)) { 465 if (blkoff == MSDOSFSROOT_OFS) 466 return EROFS; /* really? XXX */ 467 468 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 469 if (error) 470 return (error); 471 472 /* 473 * Careful about locking second inode. 474 * This can only occur if the target is ".". 475 */ 476 if (dp->de_StartCluster == scn && isadir) 477 return (EISDIR); 478 479 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 480 return (error); 481 *vpp = DETOV(tdp); 482 cnp->cn_flags |= SAVENAME; 483 if (!lockparent) 484 VOP_UNLOCK(vdp, 0, p); 485 return (0); 486 } 487 488 /* 489 * Step through the translation in the name. We do not `vput' the 490 * directory because we may need it again if a symbolic link 491 * is relative to the current directory. Instead we save it 492 * unlocked as "pdp". We must get the target inode before unlocking 493 * the directory to insure that the inode will not be removed 494 * before we get it. We prevent deadlock by always fetching 495 * inodes from the root, moving down the directory tree. Thus 496 * when following backward pointers ".." we must unlock the 497 * parent directory before getting the requested directory. 498 * There is a potential race condition here if both the current 499 * and parent directories are removed before the VFS_VGET for the 500 * inode associated with ".." returns. We hope that this occurs 501 * infrequently since we cannot avoid this race condition without 502 * implementing a sophisticated deadlock detection algorithm. 503 * Note also that this simple deadlock detection scheme will not 504 * work if the file system has any hard links other than ".." 505 * that point backwards in the directory structure. 506 */ 507 pdp = vdp; 508 if (flags & ISDOTDOT) { 509 VOP_UNLOCK(pdp, 0, p); 510 error = deget(pmp, cluster, blkoff, &tdp); 511 if (error) { 512 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 513 return (error); 514 } 515 if (lockparent && (flags & ISLASTCN) && 516 (error = vn_lock(pdp, LK_EXCLUSIVE, p))) { 517 vput(DETOV(tdp)); 518 return (error); 519 } 520 *vpp = DETOV(tdp); 521 } else if (dp->de_StartCluster == scn && isadir) { 522 VREF(vdp); /* we want ourself, ie "." */ 523 *vpp = vdp; 524 } else { 525 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 526 return (error); 527 if (!lockparent || !(flags & ISLASTCN)) 528 VOP_UNLOCK(pdp, 0, p); 529 *vpp = DETOV(tdp); 530 } 531 532 /* 533 * Insert name into cache if appropriate. 534 */ 535 if (cnp->cn_flags & MAKEENTRY) 536 cache_enter(vdp, *vpp, cnp); 537 return (0); 538} 539 540/* 541 * dep - directory entry to copy into the directory 542 * ddep - directory to add to 543 * depp - return the address of the denode for the created directory entry 544 * if depp != 0 545 * cnp - componentname needed for Win95 long filenames 546 */ 547int 548createde(dep, ddep, depp, cnp) 549 struct denode *dep; 550 struct denode *ddep; 551 struct denode **depp; 552 struct componentname *cnp; 553{ 554 int error; 555 u_long dirclust, diroffset; 556 struct direntry *ndep; 557 struct msdosfsmount *pmp = ddep->de_pmp; 558 struct buf *bp; 559 daddr_t bn; 560 int blsize; 561 562#ifdef MSDOSFS_DEBUG 563 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 564 dep, ddep, depp, cnp); 565#endif 566 567 /* 568 * If no space left in the directory then allocate another cluster 569 * and chain it onto the end of the file. There is one exception 570 * to this. That is, if the root directory has no more space it 571 * can NOT be expanded. extendfile() checks for and fails attempts 572 * to extend the root directory. We just return an error in that 573 * case. 574 */ 575 if (ddep->de_fndoffset >= ddep->de_FileSize) { 576 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 577 - ddep->de_FileSize; 578 dirclust = de_clcount(pmp, diroffset); 579 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 580 if (error) { 581 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL); 582 return error; 583 } 584 585 /* 586 * Update the size of the directory 587 */ 588 ddep->de_FileSize += de_cn2off(pmp, dirclust); 589 } 590 591 /* 592 * We just read in the cluster with space. Copy the new directory 593 * entry in. Then write it to disk. NOTE: DOS directories 594 * do not get smaller as clusters are emptied. 595 */ 596 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 597 &bn, &dirclust, &blsize); 598 if (error) 599 return error; 600 diroffset = ddep->de_fndoffset; 601 if (dirclust != MSDOSFSROOT) 602 diroffset &= pmp->pm_crbomask; 603 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 604 brelse(bp); 605 return error; 606 } 607 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 608 609 DE_EXTERNALIZE(ndep, dep); 610 611 /* 612 * Now write the Win95 long name 613 */ 614 if (ddep->de_fndcnt > 0) { 615 u_int8_t chksum = winChksum(ndep->deName); 616 const u_char *un = (const u_char *)cnp->cn_nameptr; 617 int unlen = cnp->cn_namelen; 618 int cnt = 1; 619 620 while (--ddep->de_fndcnt >= 0) { 621 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 622 if ((error = bwrite(bp)) != 0) 623 return error; 624 625 ddep->de_fndoffset -= sizeof(struct direntry); 626 error = pcbmap(ddep, 627 de_cluster(pmp, 628 ddep->de_fndoffset), 629 &bn, 0, &blsize); 630 if (error) 631 return error; 632 633 error = bread(pmp->pm_devvp, bn, blsize, 634 NOCRED, &bp); 635 if (error) { 636 brelse(bp); 637 return error; 638 } 639 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 640 } else { 641 ndep--; 642 ddep->de_fndoffset -= sizeof(struct direntry); 643 } 644 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 645 cnt++, chksum, 646 (pmp->pm_flags & MSDOSFSMNT_U2WTABLE) ? 647 pmp->pm_u2w : NULL)); 648 break; 649 } 650 } 651 652 if ((error = bwrite(bp)) != 0) 653 return error; 654 655 /* 656 * If they want us to return with the denode gotten. 657 */ 658 if (depp) { 659 if (dep->de_Attributes & ATTR_DIRECTORY) { 660 dirclust = dep->de_StartCluster; 661 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 662 dirclust = MSDOSFSROOT; 663 if (dirclust == MSDOSFSROOT) 664 diroffset = MSDOSFSROOT_OFS; 665 else 666 diroffset = 0; 667 } 668 return deget(pmp, dirclust, diroffset, depp); 669 } 670 671 return 0; 672} 673 674/* 675 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 676 * return 0 if not empty or error. 677 */ 678int 679dosdirempty(dep) 680 struct denode *dep; 681{ 682 int blsize; 683 int error; 684 u_long cn; 685 daddr_t bn; 686 struct buf *bp; 687 struct msdosfsmount *pmp = dep->de_pmp; 688 struct direntry *dentp; 689 690 /* 691 * Since the filesize field in directory entries for a directory is 692 * zero, we just have to feel our way through the directory until 693 * we hit end of file. 694 */ 695 for (cn = 0;; cn++) { 696 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 697 if (error == E2BIG) 698 return (1); /* it's empty */ 699 return (0); 700 } 701 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 702 if (error) { 703 brelse(bp); 704 return (0); 705 } 706 for (dentp = (struct direntry *)bp->b_data; 707 (char *)dentp < bp->b_data + blsize; 708 dentp++) { 709 if (dentp->deName[0] != SLOT_DELETED && 710 (dentp->deAttributes & ATTR_VOLUME) == 0) { 711 /* 712 * In dos directories an entry whose name 713 * starts with SLOT_EMPTY (0) starts the 714 * beginning of the unused part of the 715 * directory, so we can just return that it 716 * is empty. 717 */ 718 if (dentp->deName[0] == SLOT_EMPTY) { 719 brelse(bp); 720 return (1); 721 } 722 /* 723 * Any names other than "." and ".." in a 724 * directory mean it is not empty. 725 */ 726 if (bcmp(dentp->deName, ". ", 11) && 727 bcmp(dentp->deName, ".. ", 11)) { 728 brelse(bp); 729#ifdef MSDOSFS_DEBUG 730 printf("dosdirempty(): entry found %02x, %02x\n", 731 dentp->deName[0], dentp->deName[1]); 732#endif 733 return (0); /* not empty */ 734 } 735 } 736 } 737 brelse(bp); 738 } 739 /* NOTREACHED */ 740} 741 742/* 743 * Check to see if the directory described by target is in some 744 * subdirectory of source. This prevents something like the following from 745 * succeeding and leaving a bunch or files and directories orphaned. mv 746 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 747 * 748 * source - the inode for /a/b/c 749 * target - the inode for /a/b/c/d/e/f 750 * 751 * Returns 0 if target is NOT a subdirectory of source. 752 * Otherwise returns a non-zero error number. 753 * The target inode is always unlocked on return. 754 */ 755int 756doscheckpath(source, target) 757 struct denode *source; 758 struct denode *target; 759{ 760 daddr_t scn; 761 struct msdosfsmount *pmp; 762 struct direntry *ep; 763 struct denode *dep; 764 struct buf *bp = NULL; 765 int error = 0; 766 767 dep = target; 768 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 769 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 770 error = ENOTDIR; 771 goto out; 772 } 773 if (dep->de_StartCluster == source->de_StartCluster) { 774 error = EEXIST; 775 goto out; 776 } 777 if (dep->de_StartCluster == MSDOSFSROOT) 778 goto out; 779 pmp = dep->de_pmp; 780#ifdef DIAGNOSTIC 781 if (pmp != source->de_pmp) 782 panic("doscheckpath: source and target on different filesystems"); 783#endif 784 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 785 goto out; 786 787 for (;;) { 788 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 789 error = ENOTDIR; 790 break; 791 } 792 scn = dep->de_StartCluster; 793 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 794 pmp->pm_bpcluster, NOCRED, &bp); 795 if (error) 796 break; 797 798 ep = (struct direntry *) bp->b_data + 1; 799 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 800 bcmp(ep->deName, ".. ", 11) != 0) { 801 error = ENOTDIR; 802 break; 803 } 804 scn = getushort(ep->deStartCluster); 805 if (FAT32(pmp)) 806 scn |= getushort(ep->deHighClust) << 16; 807 808 if (scn == source->de_StartCluster) { 809 error = EINVAL; 810 break; 811 } 812 if (scn == MSDOSFSROOT) 813 break; 814 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 815 /* 816 * scn should be 0 in this case, 817 * but we silently ignore the error. 818 */ 819 break; 820 } 821 822 vput(DETOV(dep)); 823 brelse(bp); 824 bp = NULL; 825 /* NOTE: deget() clears dep on error */ 826 if ((error = deget(pmp, scn, 0, &dep)) != 0) 827 break; 828 } 829out:; 830 if (bp) 831 brelse(bp); 832 if (error == ENOTDIR) 833 printf("doscheckpath(): .. not a directory?\n"); 834 if (dep != NULL) 835 vput(DETOV(dep)); 836 return (error); 837} 838 839/* 840 * Read in the disk block containing the directory entry (dirclu, dirofs) 841 * and return the address of the buf header, and the address of the 842 * directory entry within the block. 843 */ 844int 845readep(pmp, dirclust, diroffset, bpp, epp) 846 struct msdosfsmount *pmp; 847 u_long dirclust, diroffset; 848 struct buf **bpp; 849 struct direntry **epp; 850{ 851 int error; 852 daddr_t bn; 853 int blsize; 854 u_long boff; 855 856 boff = diroffset & ~pmp->pm_crbomask; 857 blsize = pmp->pm_bpcluster; 858 if (dirclust == MSDOSFSROOT 859 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 860 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 861 bn = detobn(pmp, dirclust, diroffset); 862 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 863 brelse(*bpp); 864 *bpp = NULL; 865 return (error); 866 } 867 if (epp) 868 *epp = bptoep(pmp, *bpp, diroffset); 869 return (0); 870} 871 872/* 873 * Read in the disk block containing the directory entry dep came from and 874 * return the address of the buf header, and the address of the directory 875 * entry within the block. 876 */ 877int 878readde(dep, bpp, epp) 879 struct denode *dep; 880 struct buf **bpp; 881 struct direntry **epp; 882{ 883 884 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 885 bpp, epp)); 886} 887 888/* 889 * Remove a directory entry. At this point the file represented by the 890 * directory entry to be removed is still full length until noone has it 891 * open. When the file no longer being used msdosfs_inactive() is called 892 * and will truncate the file to 0 length. When the vnode containing the 893 * denode is needed for some other purpose by VFS it will call 894 * msdosfs_reclaim() which will remove the denode from the denode cache. 895 */ 896int 897removede(pdep, dep) 898 struct denode *pdep; /* directory where the entry is removed */ 899 struct denode *dep; /* file to be removed */ 900{ 901 int error; 902 struct direntry *ep; 903 struct buf *bp; 904 daddr_t bn; 905 int blsize; 906 struct msdosfsmount *pmp = pdep->de_pmp; 907 u_long offset = pdep->de_fndoffset; 908 909#ifdef MSDOSFS_DEBUG 910 printf("removede(): filename %s, dep %p, offset %08lx\n", 911 dep->de_Name, dep, offset); 912#endif 913 914 dep->de_refcnt--; 915 offset += sizeof(struct direntry); 916 do { 917 offset -= sizeof(struct direntry); 918 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 919 if (error) 920 return error; 921 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 922 if (error) { 923 brelse(bp); 924 return error; 925 } 926 ep = bptoep(pmp, bp, offset); 927 /* 928 * Check whether, if we came here the second time, i.e. 929 * when underflowing into the previous block, the last 930 * entry in this block is a longfilename entry, too. 931 */ 932 if (ep->deAttributes != ATTR_WIN95 933 && offset != pdep->de_fndoffset) { 934 brelse(bp); 935 break; 936 } 937 offset += sizeof(struct direntry); 938 while (1) { 939 /* 940 * We are a bit agressive here in that we delete any Win95 941 * entries preceding this entry, not just the ones we "own". 942 * Since these presumably aren't valid anyway, 943 * there should be no harm. 944 */ 945 offset -= sizeof(struct direntry); 946 ep--->deName[0] = SLOT_DELETED; 947 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 948 || !(offset & pmp->pm_crbomask) 949 || ep->deAttributes != ATTR_WIN95) 950 break; 951 } 952 if ((error = bwrite(bp)) != 0) 953 return error; 954 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 955 && !(offset & pmp->pm_crbomask) 956 && offset); 957 return 0; 958} 959 960/* 961 * Create a unique DOS name in dvp 962 */ 963int 964uniqdosname(dep, cnp, cp) 965 struct denode *dep; 966 struct componentname *cnp; 967 u_char *cp; 968{ 969 struct msdosfsmount *pmp = dep->de_pmp; 970 struct direntry *dentp; 971 int gen; 972 int blsize; 973 u_long cn; 974 daddr_t bn; 975 struct buf *bp; 976 int error; 977 978 for (gen = 1;; gen++) { 979 /* 980 * Generate DOS name with generation number 981 */ 982 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 983 cnp->cn_namelen, gen)) 984 return gen == 1 ? EINVAL : EEXIST; 985 986 /* 987 * Now look for a dir entry with this exact name 988 */ 989 for (cn = error = 0; !error; cn++) { 990 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 991 if (error == E2BIG) /* EOF reached and not found */ 992 return 0; 993 return error; 994 } 995 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 996 if (error) { 997 brelse(bp); 998 return error; 999 } 1000 for (dentp = (struct direntry *)bp->b_data; 1001 (char *)dentp < bp->b_data + blsize; 1002 dentp++) { 1003 if (dentp->deName[0] == SLOT_EMPTY) { 1004 /* 1005 * Last used entry and not found 1006 */ 1007 brelse(bp); 1008 return 0; 1009 } 1010 /* 1011 * Ignore volume labels and Win95 entries 1012 */ 1013 if (dentp->deAttributes & ATTR_VOLUME) 1014 continue; 1015 if (!bcmp(dentp->deName, cp, 11)) { 1016 error = EEXIST; 1017 break; 1018 } 1019 } 1020 brelse(bp); 1021 } 1022 } 1023} 1024 1025/* 1026 * Find any Win'95 long filename entry in directory dep 1027 */ 1028int 1029findwin95(dep) 1030 struct denode *dep; 1031{ 1032 struct msdosfsmount *pmp = dep->de_pmp; 1033 struct direntry *dentp; 1034 int blsize; 1035 u_long cn; 1036 daddr_t bn; 1037 struct buf *bp; 1038 1039 /* 1040 * Read through the directory looking for Win'95 entries 1041 * Note: Error currently handled just as EOF XXX 1042 */ 1043 for (cn = 0;; cn++) { 1044 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1045 return 0; 1046 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1047 brelse(bp); 1048 return 0; 1049 } 1050 for (dentp = (struct direntry *)bp->b_data; 1051 (char *)dentp < bp->b_data + blsize; 1052 dentp++) { 1053 if (dentp->deName[0] == SLOT_EMPTY) { 1054 /* 1055 * Last used entry and not found 1056 */ 1057 brelse(bp); 1058 return 0; 1059 } 1060 if (dentp->deName[0] == SLOT_DELETED) { 1061 /* 1062 * Ignore deleted files 1063 * Note: might be an indication of Win'95 anyway XXX 1064 */ 1065 continue; 1066 } 1067 if (dentp->deAttributes == ATTR_WIN95) { 1068 brelse(bp); 1069 return 1; 1070 } 1071 } 1072 brelse(bp); 1073 } 1074} 1075