msdosfs_lookup.c revision 60041
1/* $FreeBSD: head/sys/fs/msdosfs/msdosfs_lookup.c 60041 2000-05-05 09:59:14Z phk $ */ 2/* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */ 3 4/*- 5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 7 * All rights reserved. 8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by TooLs GmbH. 21 * 4. The name of TooLs GmbH may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35/* 36 * Written by Paul Popelka (paulp@uts.amdahl.com) 37 * 38 * You can do anything you want with this software, just don't say you wrote 39 * it, and don't remove this notice. 40 * 41 * This software is provided "as is". 42 * 43 * The author supplies this software to be publicly redistributed on the 44 * understanding that the author is not responsible for the correct 45 * functioning of this software in any circumstances and is not liable for 46 * any damages caused by this software. 47 * 48 * October 1992 49 */ 50 51#include <sys/param.h> 52#include <sys/systm.h> 53#include <sys/namei.h> 54#include <sys/bio.h> 55#include <sys/buf.h> 56#include <sys/vnode.h> 57#include <sys/mount.h> 58 59#include <msdosfs/bpb.h> 60#include <msdosfs/direntry.h> 61#include <msdosfs/denode.h> 62#include <msdosfs/msdosfsmount.h> 63#include <msdosfs/fat.h> 64 65/* 66 * When we search a directory the blocks containing directory entries are 67 * read and examined. The directory entries contain information that would 68 * normally be in the inode of a unix filesystem. This means that some of 69 * a directory's contents may also be in memory resident denodes (sort of 70 * an inode). This can cause problems if we are searching while some other 71 * process is modifying a directory. To prevent one process from accessing 72 * incompletely modified directory information we depend upon being the 73 * sole owner of a directory block. bread/brelse provide this service. 74 * This being the case, when a process modifies a directory it must first 75 * acquire the disk block that contains the directory entry to be modified. 76 * Then update the disk block and the denode, and then write the disk block 77 * out to disk. This way disk blocks containing directory entries and in 78 * memory denode's will be in synch. 79 */ 80int 81msdosfs_lookup(ap) 82 struct vop_cachedlookup_args /* { 83 struct vnode *a_dvp; 84 struct vnode **a_vpp; 85 struct componentname *a_cnp; 86 } */ *ap; 87{ 88 struct vnode *vdp = ap->a_dvp; 89 struct vnode **vpp = ap->a_vpp; 90 struct componentname *cnp = ap->a_cnp; 91 daddr_t bn; 92 int error; 93 int lockparent; 94 int wantparent; 95 int slotcount; 96 int slotoffset = 0; 97 int frcn; 98 u_long cluster; 99 int blkoff; 100 int diroff; 101 int blsize; 102 int isadir; /* ~0 if found direntry is a directory */ 103 u_long scn; /* starting cluster number */ 104 struct vnode *pdp; 105 struct denode *dp; 106 struct denode *tdp; 107 struct msdosfsmount *pmp; 108 struct buf *bp = 0; 109 struct direntry *dep = NULL; 110 u_char dosfilename[12]; 111 int flags = cnp->cn_flags; 112 int nameiop = cnp->cn_nameiop; 113 struct proc *p = cnp->cn_proc; 114 int unlen; 115 116 int wincnt = 1; 117 int chksum = -1; 118 int olddos = 1; 119 120#ifdef MSDOSFS_DEBUG 121 printf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr); 122#endif 123 dp = VTODE(vdp); 124 pmp = dp->de_pmp; 125 *vpp = NULL; 126 lockparent = flags & LOCKPARENT; 127 wantparent = flags & (LOCKPARENT | WANTPARENT); 128#ifdef MSDOSFS_DEBUG 129 printf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n", 130 vdp, dp, dp->de_Attributes); 131#endif 132 133 /* 134 * If they are going after the . or .. entry in the root directory, 135 * they won't find it. DOS filesystems don't have them in the root 136 * directory. So, we fake it. deget() is in on this scam too. 137 */ 138 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' && 139 (cnp->cn_namelen == 1 || 140 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) { 141 isadir = ATTR_DIRECTORY; 142 scn = MSDOSFSROOT; 143#ifdef MSDOSFS_DEBUG 144 printf("msdosfs_lookup(): looking for . or .. in root directory\n"); 145#endif 146 cluster = MSDOSFSROOT; 147 blkoff = MSDOSFSROOT_OFS; 148 goto foundroot; 149 } 150 151 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 152 cnp->cn_namelen, 0, 153 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 154 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) { 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 olddos = 1; 172 } 173 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen); 174 175 /* 176 * Suppress search for slots unless creating 177 * file and at end of pathname, in which case 178 * we watch for a place to put the new file in 179 * case it doesn't already exist. 180 */ 181 slotcount = wincnt; 182 if ((nameiop == CREATE || nameiop == RENAME) && 183 (flags & ISLASTCN)) 184 slotcount = 0; 185 186#ifdef MSDOSFS_DEBUG 187 printf("msdosfs_lookup(): dos version of filename %s, length %ld\n", 188 dosfilename, cnp->cn_namelen); 189#endif 190 /* 191 * Search the directory pointed at by vdp for the name pointed at 192 * by cnp->cn_nameptr. 193 */ 194 tdp = NULL; 195 /* 196 * The outer loop ranges over the clusters that make up the 197 * directory. Note that the root directory is different from all 198 * other directories. It has a fixed number of blocks that are not 199 * part of the pool of allocatable clusters. So, we treat it a 200 * little differently. The root directory starts at "cluster" 0. 201 */ 202 diroff = 0; 203 for (frcn = 0;; frcn++) { 204 error = pcbmap(dp, frcn, &bn, &cluster, &blsize); 205 if (error) { 206 if (error == E2BIG) 207 break; 208 return (error); 209 } 210 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 211 if (error) { 212 brelse(bp); 213 return (error); 214 } 215 for (blkoff = 0; blkoff < blsize; 216 blkoff += sizeof(struct direntry), 217 diroff += sizeof(struct direntry)) { 218 dep = (struct direntry *)(bp->b_data + blkoff); 219 /* 220 * If the slot is empty and we are still looking 221 * for an empty then remember this one. If the 222 * slot is not empty then check to see if it 223 * matches what we are looking for. If the slot 224 * has never been filled with anything, then the 225 * remainder of the directory has never been used, 226 * so there is no point in searching it. 227 */ 228 if (dep->deName[0] == SLOT_EMPTY || 229 dep->deName[0] == SLOT_DELETED) { 230 /* 231 * Drop memory of previous long matches 232 */ 233 chksum = -1; 234 235 if (slotcount < wincnt) { 236 slotcount++; 237 slotoffset = diroff; 238 } 239 if (dep->deName[0] == SLOT_EMPTY) { 240 brelse(bp); 241 goto notfound; 242 } 243 } else { 244 /* 245 * If there wasn't enough space for our winentries, 246 * forget about the empty space 247 */ 248 if (slotcount < wincnt) 249 slotcount = 0; 250 251 /* 252 * Check for Win95 long filename entry 253 */ 254 if (dep->deAttributes == ATTR_WIN95) { 255 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 256 continue; 257 258 chksum = winChkName((const u_char *)cnp->cn_nameptr, 259 unlen, 260 (struct winentry *)dep, 261 chksum, 262 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 263 pmp->pm_u2w, 264 pmp->pm_flags & MSDOSFSMNT_ULTABLE, 265 pmp->pm_ul); 266 continue; 267 } 268 269 /* 270 * Ignore volume labels (anywhere, not just 271 * the root directory). 272 */ 273 if (dep->deAttributes & ATTR_VOLUME) { 274 chksum = -1; 275 continue; 276 } 277 278 /* 279 * Check for a checksum or name match 280 */ 281 if (chksum != winChksum(dep->deName) 282 && (!olddos || bcmp(dosfilename, dep->deName, 11))) { 283 chksum = -1; 284 continue; 285 } 286#ifdef MSDOSFS_DEBUG 287 printf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 288 blkoff, diroff); 289#endif 290 /* 291 * Remember where this directory 292 * entry came from for whoever did 293 * this lookup. 294 */ 295 dp->de_fndoffset = diroff; 296 dp->de_fndcnt = wincnt - 1; 297 298 goto found; 299 } 300 } /* for (blkoff = 0; .... */ 301 /* 302 * Release the buffer holding the directory cluster just 303 * searched. 304 */ 305 brelse(bp); 306 } /* for (frcn = 0; ; frcn++) */ 307 308notfound: 309 /* 310 * We hold no disk buffers at this point. 311 */ 312 313 /* 314 * Fixup the slot description to point to the place where 315 * we might put the new DOS direntry (putting the Win95 316 * long name entries before that) 317 */ 318 if (!slotcount) { 319 slotcount = 1; 320 slotoffset = diroff; 321 } 322 if (wincnt > slotcount) 323 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 324 325 /* 326 * If we get here we didn't find the entry we were looking for. But 327 * that's ok if we are creating or renaming and are at the end of 328 * the pathname and the directory hasn't been removed. 329 */ 330#ifdef MSDOSFS_DEBUG 331 printf("msdosfs_lookup(): op %d, refcnt %ld\n", 332 nameiop, dp->de_refcnt); 333 printf(" slotcount %d, slotoffset %d\n", 334 slotcount, slotoffset); 335#endif 336 if ((nameiop == CREATE || nameiop == RENAME) && 337 (flags & ISLASTCN) && dp->de_refcnt != 0) { 338 /* 339 * Access for write is interpreted as allowing 340 * creation of files in the directory. 341 */ 342 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 343 if (error) 344 return (error); 345 /* 346 * Return an indication of where the new directory 347 * entry should be put. 348 */ 349 dp->de_fndoffset = slotoffset; 350 dp->de_fndcnt = wincnt - 1; 351 352 /* 353 * We return with the directory locked, so that 354 * the parameters we set up above will still be 355 * valid if we actually decide to do a direnter(). 356 * We return ni_vp == NULL to indicate that the entry 357 * does not currently exist; we leave a pointer to 358 * the (locked) directory inode in ndp->ni_dvp. 359 * The pathname buffer is saved so that the name 360 * can be obtained later. 361 * 362 * NB - if the directory is unlocked, then this 363 * information cannot be used. 364 */ 365 cnp->cn_flags |= SAVENAME; 366 if (!lockparent) 367 VOP_UNLOCK(vdp, 0, p); 368 return (EJUSTRETURN); 369 } 370 /* 371 * Insert name into cache (as non-existent) if appropriate. 372 */ 373 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 374 cache_enter(vdp, *vpp, cnp); 375 return (ENOENT); 376 377found: 378 /* 379 * NOTE: We still have the buffer with matched directory entry at 380 * this point. 381 */ 382 isadir = dep->deAttributes & ATTR_DIRECTORY; 383 scn = getushort(dep->deStartCluster); 384 if (FAT32(pmp)) { 385 scn |= getushort(dep->deHighClust) << 16; 386 if (scn == pmp->pm_rootdirblk) { 387 /* 388 * There should actually be 0 here. 389 * Just ignore the error. 390 */ 391 scn = MSDOSFSROOT; 392 } 393 } 394 395 if (isadir) { 396 cluster = scn; 397 if (cluster == MSDOSFSROOT) 398 blkoff = MSDOSFSROOT_OFS; 399 else 400 blkoff = 0; 401 } else if (cluster == MSDOSFSROOT) 402 blkoff = diroff; 403 404 /* 405 * Now release buf to allow deget to read the entry again. 406 * Reserving it here and giving it to deget could result 407 * in a deadlock. 408 */ 409 brelse(bp); 410 bp = 0; 411 412foundroot: 413 /* 414 * If we entered at foundroot, then we are looking for the . or .. 415 * entry of the filesystems root directory. isadir and scn were 416 * setup before jumping here. And, bp is already null. 417 */ 418 if (FAT32(pmp) && scn == MSDOSFSROOT) 419 scn = pmp->pm_rootdirblk; 420 421 /* 422 * If deleting, and at end of pathname, return 423 * parameters which can be used to remove file. 424 * If the wantparent flag isn't set, we return only 425 * the directory (in ndp->ni_dvp), otherwise we go 426 * on and lock the inode, being careful with ".". 427 */ 428 if (nameiop == DELETE && (flags & ISLASTCN)) { 429 /* 430 * Don't allow deleting the root. 431 */ 432 if (blkoff == MSDOSFSROOT_OFS) 433 return EROFS; /* really? XXX */ 434 435 /* 436 * Write access to directory required to delete files. 437 */ 438 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 439 if (error) 440 return (error); 441 442 /* 443 * Return pointer to current entry in dp->i_offset. 444 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 445 */ 446 if (dp->de_StartCluster == scn && isadir) { /* "." */ 447 VREF(vdp); 448 *vpp = vdp; 449 return (0); 450 } 451 error = deget(pmp, cluster, blkoff, &tdp); 452 if (error) 453 return (error); 454 *vpp = DETOV(tdp); 455 if (!lockparent) 456 VOP_UNLOCK(vdp, 0, p); 457 return (0); 458 } 459 460 /* 461 * If rewriting (RENAME), return the inode and the 462 * information required to rewrite the present directory 463 * Must get inode of directory entry to verify it's a 464 * regular file, or empty directory. 465 */ 466 if (nameiop == RENAME && wantparent && 467 (flags & ISLASTCN)) { 468 if (blkoff == MSDOSFSROOT_OFS) 469 return EROFS; /* really? XXX */ 470 471 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 472 if (error) 473 return (error); 474 475 /* 476 * Careful about locking second inode. 477 * This can only occur if the target is ".". 478 */ 479 if (dp->de_StartCluster == scn && isadir) 480 return (EISDIR); 481 482 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 483 return (error); 484 *vpp = DETOV(tdp); 485 cnp->cn_flags |= SAVENAME; 486 if (!lockparent) 487 VOP_UNLOCK(vdp, 0, p); 488 return (0); 489 } 490 491 /* 492 * Step through the translation in the name. We do not `vput' the 493 * directory because we may need it again if a symbolic link 494 * is relative to the current directory. Instead we save it 495 * unlocked as "pdp". We must get the target inode before unlocking 496 * the directory to insure that the inode will not be removed 497 * before we get it. We prevent deadlock by always fetching 498 * inodes from the root, moving down the directory tree. Thus 499 * when following backward pointers ".." we must unlock the 500 * parent directory before getting the requested directory. 501 * There is a potential race condition here if both the current 502 * and parent directories are removed before the VFS_VGET for the 503 * inode associated with ".." returns. We hope that this occurs 504 * infrequently since we cannot avoid this race condition without 505 * implementing a sophisticated deadlock detection algorithm. 506 * Note also that this simple deadlock detection scheme will not 507 * work if the file system has any hard links other than ".." 508 * that point backwards in the directory structure. 509 */ 510 pdp = vdp; 511 if (flags & ISDOTDOT) { 512 VOP_UNLOCK(pdp, 0, p); 513 error = deget(pmp, cluster, blkoff, &tdp); 514 if (error) { 515 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 516 return (error); 517 } 518 if (lockparent && (flags & ISLASTCN) && 519 (error = vn_lock(pdp, LK_EXCLUSIVE, p))) { 520 vput(DETOV(tdp)); 521 return (error); 522 } 523 *vpp = DETOV(tdp); 524 } else if (dp->de_StartCluster == scn && isadir) { 525 VREF(vdp); /* we want ourself, ie "." */ 526 *vpp = vdp; 527 } else { 528 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 529 return (error); 530 if (!lockparent || !(flags & ISLASTCN)) 531 VOP_UNLOCK(pdp, 0, p); 532 *vpp = DETOV(tdp); 533 } 534 535 /* 536 * Insert name into cache if appropriate. 537 */ 538 if (cnp->cn_flags & MAKEENTRY) 539 cache_enter(vdp, *vpp, cnp); 540 return (0); 541} 542 543/* 544 * dep - directory entry to copy into the directory 545 * ddep - directory to add to 546 * depp - return the address of the denode for the created directory entry 547 * if depp != 0 548 * cnp - componentname needed for Win95 long filenames 549 */ 550int 551createde(dep, ddep, depp, cnp) 552 struct denode *dep; 553 struct denode *ddep; 554 struct denode **depp; 555 struct componentname *cnp; 556{ 557 int error; 558 u_long dirclust, diroffset; 559 struct direntry *ndep; 560 struct msdosfsmount *pmp = ddep->de_pmp; 561 struct buf *bp; 562 daddr_t bn; 563 int blsize; 564 565#ifdef MSDOSFS_DEBUG 566 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 567 dep, ddep, depp, cnp); 568#endif 569 570 /* 571 * If no space left in the directory then allocate another cluster 572 * and chain it onto the end of the file. There is one exception 573 * to this. That is, if the root directory has no more space it 574 * can NOT be expanded. extendfile() checks for and fails attempts 575 * to extend the root directory. We just return an error in that 576 * case. 577 */ 578 if (ddep->de_fndoffset >= ddep->de_FileSize) { 579 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 580 - ddep->de_FileSize; 581 dirclust = de_clcount(pmp, diroffset); 582 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 583 if (error) { 584 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL); 585 return error; 586 } 587 588 /* 589 * Update the size of the directory 590 */ 591 ddep->de_FileSize += de_cn2off(pmp, dirclust); 592 } 593 594 /* 595 * We just read in the cluster with space. Copy the new directory 596 * entry in. Then write it to disk. NOTE: DOS directories 597 * do not get smaller as clusters are emptied. 598 */ 599 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 600 &bn, &dirclust, &blsize); 601 if (error) 602 return error; 603 diroffset = ddep->de_fndoffset; 604 if (dirclust != MSDOSFSROOT) 605 diroffset &= pmp->pm_crbomask; 606 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 607 brelse(bp); 608 return error; 609 } 610 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 611 612 DE_EXTERNALIZE(ndep, dep); 613 614 /* 615 * Now write the Win95 long name 616 */ 617 if (ddep->de_fndcnt > 0) { 618 u_int8_t chksum = winChksum(ndep->deName); 619 const u_char *un = (const u_char *)cnp->cn_nameptr; 620 int unlen = cnp->cn_namelen; 621 int cnt = 1; 622 623 while (--ddep->de_fndcnt >= 0) { 624 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 625 if ((error = bwrite(bp)) != 0) 626 return error; 627 628 ddep->de_fndoffset -= sizeof(struct direntry); 629 error = pcbmap(ddep, 630 de_cluster(pmp, 631 ddep->de_fndoffset), 632 &bn, 0, &blsize); 633 if (error) 634 return error; 635 636 error = bread(pmp->pm_devvp, bn, blsize, 637 NOCRED, &bp); 638 if (error) { 639 brelse(bp); 640 return error; 641 } 642 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 643 } else { 644 ndep--; 645 ddep->de_fndoffset -= sizeof(struct direntry); 646 } 647 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 648 cnt++, chksum, 649 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 650 pmp->pm_u2w)) 651 break; 652 } 653 } 654 655 if ((error = bwrite(bp)) != 0) 656 return error; 657 658 /* 659 * If they want us to return with the denode gotten. 660 */ 661 if (depp) { 662 if (dep->de_Attributes & ATTR_DIRECTORY) { 663 dirclust = dep->de_StartCluster; 664 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 665 dirclust = MSDOSFSROOT; 666 if (dirclust == MSDOSFSROOT) 667 diroffset = MSDOSFSROOT_OFS; 668 else 669 diroffset = 0; 670 } 671 return deget(pmp, dirclust, diroffset, depp); 672 } 673 674 return 0; 675} 676 677/* 678 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 679 * return 0 if not empty or error. 680 */ 681int 682dosdirempty(dep) 683 struct denode *dep; 684{ 685 int blsize; 686 int error; 687 u_long cn; 688 daddr_t bn; 689 struct buf *bp; 690 struct msdosfsmount *pmp = dep->de_pmp; 691 struct direntry *dentp; 692 693 /* 694 * Since the filesize field in directory entries for a directory is 695 * zero, we just have to feel our way through the directory until 696 * we hit end of file. 697 */ 698 for (cn = 0;; cn++) { 699 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 700 if (error == E2BIG) 701 return (1); /* it's empty */ 702 return (0); 703 } 704 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 705 if (error) { 706 brelse(bp); 707 return (0); 708 } 709 for (dentp = (struct direntry *)bp->b_data; 710 (char *)dentp < bp->b_data + blsize; 711 dentp++) { 712 if (dentp->deName[0] != SLOT_DELETED && 713 (dentp->deAttributes & ATTR_VOLUME) == 0) { 714 /* 715 * In dos directories an entry whose name 716 * starts with SLOT_EMPTY (0) starts the 717 * beginning of the unused part of the 718 * directory, so we can just return that it 719 * is empty. 720 */ 721 if (dentp->deName[0] == SLOT_EMPTY) { 722 brelse(bp); 723 return (1); 724 } 725 /* 726 * Any names other than "." and ".." in a 727 * directory mean it is not empty. 728 */ 729 if (bcmp(dentp->deName, ". ", 11) && 730 bcmp(dentp->deName, ".. ", 11)) { 731 brelse(bp); 732#ifdef MSDOSFS_DEBUG 733 printf("dosdirempty(): entry found %02x, %02x\n", 734 dentp->deName[0], dentp->deName[1]); 735#endif 736 return (0); /* not empty */ 737 } 738 } 739 } 740 brelse(bp); 741 } 742 /* NOTREACHED */ 743} 744 745/* 746 * Check to see if the directory described by target is in some 747 * subdirectory of source. This prevents something like the following from 748 * succeeding and leaving a bunch or files and directories orphaned. mv 749 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 750 * 751 * source - the inode for /a/b/c 752 * target - the inode for /a/b/c/d/e/f 753 * 754 * Returns 0 if target is NOT a subdirectory of source. 755 * Otherwise returns a non-zero error number. 756 * The target inode is always unlocked on return. 757 */ 758int 759doscheckpath(source, target) 760 struct denode *source; 761 struct denode *target; 762{ 763 daddr_t scn; 764 struct msdosfsmount *pmp; 765 struct direntry *ep; 766 struct denode *dep; 767 struct buf *bp = NULL; 768 int error = 0; 769 770 dep = target; 771 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 772 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 773 error = ENOTDIR; 774 goto out; 775 } 776 if (dep->de_StartCluster == source->de_StartCluster) { 777 error = EEXIST; 778 goto out; 779 } 780 if (dep->de_StartCluster == MSDOSFSROOT) 781 goto out; 782 pmp = dep->de_pmp; 783#ifdef DIAGNOSTIC 784 if (pmp != source->de_pmp) 785 panic("doscheckpath: source and target on different filesystems"); 786#endif 787 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 788 goto out; 789 790 for (;;) { 791 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 792 error = ENOTDIR; 793 break; 794 } 795 scn = dep->de_StartCluster; 796 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 797 pmp->pm_bpcluster, NOCRED, &bp); 798 if (error) 799 break; 800 801 ep = (struct direntry *) bp->b_data + 1; 802 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 803 bcmp(ep->deName, ".. ", 11) != 0) { 804 error = ENOTDIR; 805 break; 806 } 807 scn = getushort(ep->deStartCluster); 808 if (FAT32(pmp)) 809 scn |= getushort(ep->deHighClust) << 16; 810 811 if (scn == source->de_StartCluster) { 812 error = EINVAL; 813 break; 814 } 815 if (scn == MSDOSFSROOT) 816 break; 817 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 818 /* 819 * scn should be 0 in this case, 820 * but we silently ignore the error. 821 */ 822 break; 823 } 824 825 vput(DETOV(dep)); 826 brelse(bp); 827 bp = NULL; 828 /* NOTE: deget() clears dep on error */ 829 if ((error = deget(pmp, scn, 0, &dep)) != 0) 830 break; 831 } 832out:; 833 if (bp) 834 brelse(bp); 835 if (error == ENOTDIR) 836 printf("doscheckpath(): .. not a directory?\n"); 837 if (dep != NULL) 838 vput(DETOV(dep)); 839 return (error); 840} 841 842/* 843 * Read in the disk block containing the directory entry (dirclu, dirofs) 844 * and return the address of the buf header, and the address of the 845 * directory entry within the block. 846 */ 847int 848readep(pmp, dirclust, diroffset, bpp, epp) 849 struct msdosfsmount *pmp; 850 u_long dirclust, diroffset; 851 struct buf **bpp; 852 struct direntry **epp; 853{ 854 int error; 855 daddr_t bn; 856 int blsize; 857 858 blsize = pmp->pm_bpcluster; 859 if (dirclust == MSDOSFSROOT 860 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 861 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 862 bn = detobn(pmp, dirclust, diroffset); 863 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 864 brelse(*bpp); 865 *bpp = NULL; 866 return (error); 867 } 868 if (epp) 869 *epp = bptoep(pmp, *bpp, diroffset); 870 return (0); 871} 872 873/* 874 * Read in the disk block containing the directory entry dep came from and 875 * return the address of the buf header, and the address of the directory 876 * entry within the block. 877 */ 878int 879readde(dep, bpp, epp) 880 struct denode *dep; 881 struct buf **bpp; 882 struct direntry **epp; 883{ 884 885 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 886 bpp, epp)); 887} 888 889/* 890 * Remove a directory entry. At this point the file represented by the 891 * directory entry to be removed is still full length until noone has it 892 * open. When the file no longer being used msdosfs_inactive() is called 893 * and will truncate the file to 0 length. When the vnode containing the 894 * denode is needed for some other purpose by VFS it will call 895 * msdosfs_reclaim() which will remove the denode from the denode cache. 896 */ 897int 898removede(pdep, dep) 899 struct denode *pdep; /* directory where the entry is removed */ 900 struct denode *dep; /* file to be removed */ 901{ 902 int error; 903 struct direntry *ep; 904 struct buf *bp; 905 daddr_t bn; 906 int blsize; 907 struct msdosfsmount *pmp = pdep->de_pmp; 908 u_long offset = pdep->de_fndoffset; 909 910#ifdef MSDOSFS_DEBUG 911 printf("removede(): filename %s, dep %p, offset %08lx\n", 912 dep->de_Name, dep, offset); 913#endif 914 915 dep->de_refcnt--; 916 offset += sizeof(struct direntry); 917 do { 918 offset -= sizeof(struct direntry); 919 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 920 if (error) 921 return error; 922 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 923 if (error) { 924 brelse(bp); 925 return error; 926 } 927 ep = bptoep(pmp, bp, offset); 928 /* 929 * Check whether, if we came here the second time, i.e. 930 * when underflowing into the previous block, the last 931 * entry in this block is a longfilename entry, too. 932 */ 933 if (ep->deAttributes != ATTR_WIN95 934 && offset != pdep->de_fndoffset) { 935 brelse(bp); 936 break; 937 } 938 offset += sizeof(struct direntry); 939 while (1) { 940 /* 941 * We are a bit agressive here in that we delete any Win95 942 * entries preceding this entry, not just the ones we "own". 943 * Since these presumably aren't valid anyway, 944 * there should be no harm. 945 */ 946 offset -= sizeof(struct direntry); 947 ep--->deName[0] = SLOT_DELETED; 948 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 949 || !(offset & pmp->pm_crbomask) 950 || ep->deAttributes != ATTR_WIN95) 951 break; 952 } 953 if ((error = bwrite(bp)) != 0) 954 return error; 955 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 956 && !(offset & pmp->pm_crbomask) 957 && offset); 958 return 0; 959} 960 961/* 962 * Create a unique DOS name in dvp 963 */ 964int 965uniqdosname(dep, cnp, cp) 966 struct denode *dep; 967 struct componentname *cnp; 968 u_char *cp; 969{ 970 struct msdosfsmount *pmp = dep->de_pmp; 971 struct direntry *dentp; 972 int gen; 973 int blsize; 974 u_long cn; 975 daddr_t bn; 976 struct buf *bp; 977 int error; 978 979 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 980 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 981 cnp->cn_namelen, 0, 982 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 983 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu) ? 984 0 : EINVAL); 985 986 for (gen = 1;; gen++) { 987 /* 988 * Generate DOS name with generation number 989 */ 990 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 991 cnp->cn_namelen, gen, 992 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 993 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) 994 return gen == 1 ? EINVAL : EEXIST; 995 996 /* 997 * Now look for a dir entry with this exact name 998 */ 999 for (cn = error = 0; !error; cn++) { 1000 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 1001 if (error == E2BIG) /* EOF reached and not found */ 1002 return 0; 1003 return error; 1004 } 1005 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 1006 if (error) { 1007 brelse(bp); 1008 return error; 1009 } 1010 for (dentp = (struct direntry *)bp->b_data; 1011 (char *)dentp < bp->b_data + blsize; 1012 dentp++) { 1013 if (dentp->deName[0] == SLOT_EMPTY) { 1014 /* 1015 * Last used entry and not found 1016 */ 1017 brelse(bp); 1018 return 0; 1019 } 1020 /* 1021 * Ignore volume labels and Win95 entries 1022 */ 1023 if (dentp->deAttributes & ATTR_VOLUME) 1024 continue; 1025 if (!bcmp(dentp->deName, cp, 11)) { 1026 error = EEXIST; 1027 break; 1028 } 1029 } 1030 brelse(bp); 1031 } 1032 } 1033} 1034 1035/* 1036 * Find any Win'95 long filename entry in directory dep 1037 */ 1038int 1039findwin95(dep) 1040 struct denode *dep; 1041{ 1042 struct msdosfsmount *pmp = dep->de_pmp; 1043 struct direntry *dentp; 1044 int blsize, win95; 1045 u_long cn; 1046 daddr_t bn; 1047 struct buf *bp; 1048 1049 win95 = 1; 1050 /* 1051 * Read through the directory looking for Win'95 entries 1052 * Note: Error currently handled just as EOF XXX 1053 */ 1054 for (cn = 0;; cn++) { 1055 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1056 return (win95); 1057 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1058 brelse(bp); 1059 return (win95); 1060 } 1061 for (dentp = (struct direntry *)bp->b_data; 1062 (char *)dentp < bp->b_data + blsize; 1063 dentp++) { 1064 if (dentp->deName[0] == SLOT_EMPTY) { 1065 /* 1066 * Last used entry and not found 1067 */ 1068 brelse(bp); 1069 return (win95); 1070 } 1071 if (dentp->deName[0] == SLOT_DELETED) { 1072 /* 1073 * Ignore deleted files 1074 * Note: might be an indication of Win'95 anyway XXX 1075 */ 1076 continue; 1077 } 1078 if (dentp->deAttributes == ATTR_WIN95) { 1079 brelse(bp); 1080 return 1; 1081 } 1082 win95 = 0; 1083 } 1084 brelse(bp); 1085 } 1086} 1087