1 /* $FreeBSD$ */ 2 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */ 3 4 /*- 5 * SPDX-License-Identifier: BSD-4-Clause 6 * 7 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 8 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 9 * All rights reserved. 10 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by TooLs GmbH. 23 * 4. The name of TooLs GmbH may not be used to endorse or promote products 24 * derived from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 31 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 32 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 33 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 34 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 35 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 /*- 38 * Written by Paul Popelka (paulp@uts.amdahl.com) 39 * 40 * You can do anything you want with this software, just don't say you wrote 41 * it, and don't remove this notice. 42 * 43 * This software is provided "as is". 44 * 45 * The author supplies this software to be publicly redistributed on the 46 * understanding that the author is not responsible for the correct 47 * functioning of this software in any circumstances and is not liable for 48 * any damages caused by this software. 49 * 50 * October 1992 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/buf.h> 56 #include <sys/proc.h> 57 #include <sys/mount.h> 58 #include <sys/namei.h> 59 #include <sys/vnode.h> 60 61 #include <sys/buf2.h> 62 63 #include <vfs/msdosfs/bpb.h> 64 #include <vfs/msdosfs/direntry.h> 65 #include <vfs/msdosfs/denode.h> 66 #include <vfs/msdosfs/fat.h> 67 #include <vfs/msdosfs/msdosfsmount.h> 68 69 static int 70 msdosfs_lookup_checker(struct msdosfsmount *pmp, struct vnode *dvp, 71 struct denode *tdp, struct vnode **vpp) 72 { 73 struct vnode *vp; 74 75 vp = DETOV(tdp); 76 77 /* 78 * Lookup assumes that directory cannot be hardlinked. 79 * Corrupted msdosfs filesystem could break this assumption. 80 */ 81 if (vp == dvp) { 82 vput(vp); 83 *vpp = NULL; 84 return (EBADF); 85 } 86 87 *vpp = vp; 88 return (0); 89 } 90 91 /* 92 * XXX Implement .vop_nresolve and replace old vnops which depend on this. 93 */ 94 /* 95 * When we search a directory the blocks containing directory entries are 96 * read and examined. The directory entries contain information that would 97 * normally be in the inode of a unix filesystem. This means that some of 98 * a directory's contents may also be in memory resident denodes (sort of 99 * an inode). This can cause problems if we are searching while some other 100 * process is modifying a directory. To prevent one process from accessing 101 * incompletely modified directory information we depend upon being the 102 * sole owner of a directory block. bread/brelse provide this service. 103 * This being the case, when a process modifies a directory it must first 104 * acquire the disk block that contains the directory entry to be modified. 105 * Then update the disk block and the denode, and then write the disk block 106 * out to disk. This way disk blocks containing directory entries and in 107 * memory denode's will be in synch. 108 */ 109 int 110 msdosfs_lookup(struct vop_old_lookup_args *ap) 111 { 112 struct mbnambuf nb; 113 struct vnode *vdp = ap->a_dvp; 114 struct vnode **vpp = ap->a_vpp; 115 struct componentname *cnp = ap->a_cnp; 116 daddr_t bn; 117 int error; 118 int lockparent; 119 int wantparent; 120 int slotcount; 121 int slotoffset = 0; 122 int frcn; 123 u_long cluster; 124 int blkoff; 125 int diroff; 126 int blsize; 127 int isadir; /* ~0 if found direntry is a directory */ 128 u_long scn; /* starting cluster number */ 129 struct vnode *pdp; 130 struct denode *dp; 131 struct denode *tdp; 132 struct msdosfsmount *pmp; 133 struct buf *bp = NULL; 134 struct direntry *dep = NULL; 135 u_char dosfilename[12]; 136 int flags = cnp->cn_flags; 137 int nameiop = cnp->cn_nameiop; 138 int unlen; 139 140 int wincnt = 1; 141 int chksum = -1, chksum_ok; 142 int olddos = 1; 143 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 144 145 mprintf("msdosfs_lookup(): looking for %s\n", cnp->cn_nameptr); 146 dp = VTODE(vdp); 147 pmp = dp->de_pmp; 148 *vpp = NULL; 149 lockparent = flags & CNP_LOCKPARENT; 150 wantparent = flags & (CNP_LOCKPARENT | CNP_WANTPARENT); 151 mprintf("msdosfs_lookup(): vdp %p, dp %p, Attr %02x\n", 152 vdp, dp, dp->de_Attributes); 153 154 /* 155 * If they are going after the . or .. entry in the root directory, 156 * they won't find it. DOS filesystems don't have them in the root 157 * directory. So, we fake it. deget() is in on this scam too. 158 */ 159 if ((vdp->v_flag & VROOT) && cnp->cn_nameptr[0] == '.' && 160 (cnp->cn_namelen == 1 || 161 (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.'))) { 162 isadir = ATTR_DIRECTORY; 163 scn = MSDOSFSROOT; 164 mprintf("msdosfs_lookup(): looking for . or .. in root directory\n"); 165 cluster = MSDOSFSROOT; 166 blkoff = MSDOSFSROOT_OFS; 167 goto foundroot; 168 } 169 170 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 171 cnp->cn_namelen, 0, pmp)) { 172 case 0: 173 return (EINVAL); 174 case 1: 175 break; 176 case 2: 177 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 178 cnp->cn_namelen, pmp) + 1; 179 break; 180 case 3: 181 olddos = 0; 182 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 183 cnp->cn_namelen, pmp) + 1; 184 break; 185 } 186 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) { 187 wincnt = 1; 188 olddos = 1; 189 } 190 unlen = winLenFixup(cnp->cn_nameptr, cnp->cn_namelen); 191 192 /* 193 * Suppress search for slots unless creating 194 * file and at end of pathname, in which case 195 * we watch for a place to put the new file in 196 * case it doesn't already exist. 197 */ 198 slotcount = wincnt; 199 if (nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) 200 slotcount = 0; 201 202 mprintf("msdosfs_lookup(): dos version of filename %s, length %ld\n", 203 dosfilename, cnp->cn_namelen); 204 /* 205 * Search the directory pointed at by vdp for the name pointed at 206 * by cnp->cn_nameptr. 207 */ 208 tdp = NULL; 209 mbnambuf_init(&nb); 210 /* 211 * The outer loop ranges over the clusters that make up the 212 * directory. Note that the root directory is different from all 213 * other directories. It has a fixed number of blocks that are not 214 * part of the pool of allocatable clusters. So, we treat it a 215 * little differently. The root directory starts at "cluster" 0. 216 */ 217 diroff = 0; 218 for (frcn = 0;; frcn++) { 219 error = pcbmap(dp, frcn, &bn, &cluster, &blsize); 220 if (error) { 221 if (error == E2BIG) 222 break; 223 return (error); 224 } 225 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp); 226 if (error) { 227 brelse(bp); 228 return (error); 229 } 230 for (blkoff = 0; blkoff < blsize; 231 blkoff += sizeof(struct direntry), 232 diroff += sizeof(struct direntry)) { 233 dep = (struct direntry *)(bp->b_data + blkoff); 234 /* 235 * If the slot is empty and we are still looking 236 * for an empty then remember this one. If the 237 * slot is not empty then check to see if it 238 * matches what we are looking for. If the slot 239 * has never been filled with anything, then the 240 * remainder of the directory has never been used, 241 * so there is no point in searching it. 242 */ 243 if (dep->deName[0] == SLOT_EMPTY || 244 dep->deName[0] == SLOT_DELETED) { 245 /* 246 * Drop memory of previous long matches 247 */ 248 chksum = -1; 249 mbnambuf_init(&nb); 250 251 if (slotcount < wincnt) { 252 slotcount++; 253 slotoffset = diroff; 254 } 255 if (dep->deName[0] == SLOT_EMPTY) { 256 brelse(bp); 257 goto notfound; 258 } 259 } else { 260 /* 261 * If there wasn't enough space for our winentries, 262 * forget about the empty space 263 */ 264 if (slotcount < wincnt) 265 slotcount = 0; 266 267 /* 268 * Check for Win95 long filename entry 269 */ 270 if (dep->deAttributes == ATTR_WIN95) { 271 if (pmp->pm_flags & 272 MSDOSFSMNT_SHORTNAME) 273 continue; 274 chksum = win2unixfn(&nb, 275 (struct winentry *)dep, chksum, 276 pmp); 277 continue; 278 } 279 280 chksum = winChkName(&nb, 281 (const u_char *)cnp->cn_nameptr, unlen, 282 chksum, pmp); 283 if (chksum == -2) { 284 chksum = -1; 285 continue; 286 } 287 288 /* 289 * Ignore volume labels (anywhere, not just 290 * the root directory). 291 */ 292 if (dep->deAttributes & ATTR_VOLUME) { 293 chksum = -1; 294 continue; 295 } 296 297 /* 298 * Check for a checksum or name match 299 */ 300 chksum_ok = (chksum == winChksum(dep->deName)); 301 if (!chksum_ok 302 && (!olddos || memcmp(dosfilename, 303 dep->deName, 11))) { 304 chksum = -1; 305 continue; 306 } 307 mprintf("msdosfs_lookup(): match blkoff %d, diroff %d\n", 308 blkoff, diroff); 309 /* 310 * Remember where this directory 311 * entry came from for whoever did 312 * this lookup. 313 */ 314 dp->de_fndoffset = diroff; 315 if (chksum_ok && nameiop == NAMEI_RENAME) { 316 /* 317 * Target had correct long name 318 * directory entries, reuse them 319 * as needed. 320 */ 321 dp->de_fndcnt = wincnt - 1; 322 } else { 323 /* 324 * Long name directory entries 325 * not present or corrupt, can only 326 * reuse dos directory entry. 327 */ 328 dp->de_fndcnt = 0; 329 } 330 331 goto found; 332 } 333 } /* for (blkoff = 0; .... */ 334 /* 335 * Release the buffer holding the directory cluster just 336 * searched. 337 */ 338 brelse(bp); 339 } /* for (frcn = 0; ; frcn++) */ 340 341 notfound: 342 /* 343 * We hold no disk buffers at this point. 344 */ 345 346 /* 347 * Fixup the slot description to point to the place where 348 * we might put the new DOS direntry (putting the Win95 349 * long name entries before that) 350 */ 351 if (!slotcount) { 352 slotcount = 1; 353 slotoffset = diroff; 354 } 355 if (wincnt > slotcount) 356 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 357 358 /* 359 * If we get here we didn't find the entry we were looking for. But 360 * that's ok if we are creating or renaming and are at the end of 361 * the pathname and the directory hasn't been removed. 362 */ 363 mprintf("msdosfs_lookup(): op %d, refcnt %ld\n", 364 nameiop, dp->de_refcnt); 365 mprintf(" slotcount %d, slotoffset %d\n", 366 slotcount, slotoffset); 367 if ((nameiop == NAMEI_CREATE || nameiop == NAMEI_RENAME) && 368 dp->de_refcnt > 0) { 369 /* 370 * Access for write is interpreted as allowing 371 * creation of files in the directory. 372 */ 373 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred); 374 if (error) 375 return (error); 376 /* 377 * Return an indication of where the new directory 378 * entry should be put. 379 */ 380 dp->de_fndoffset = slotoffset; 381 dp->de_fndcnt = wincnt - 1; 382 383 /* 384 * We return with the directory locked, so that 385 * the parameters we set up above will still be 386 * valid if we actually decide to do a direnter(). 387 * We return ni_vp == NULL to indicate that the entry 388 * does not currently exist; we leave a pointer to 389 * the (locked) directory inode in ndp->ni_dvp. 390 * The pathname buffer is saved so that the name 391 * can be obtained later. 392 * 393 * NB - if the directory is unlocked, then this 394 * information cannot be used. 395 */ 396 if (!lockparent) { 397 vn_unlock(vdp); 398 cnp->cn_flags |= CNP_PDIRUNLOCK; 399 } 400 return (EJUSTRETURN); 401 } 402 return (ENOENT); 403 404 found: 405 /* 406 * NOTE: We still have the buffer with matched directory entry at 407 * this point. 408 */ 409 isadir = dep->deAttributes & ATTR_DIRECTORY; 410 scn = getushort(dep->deStartCluster); 411 if (FAT32(pmp)) { 412 scn |= getushort(dep->deHighClust) << 16; 413 if (scn == pmp->pm_rootdirblk) { 414 /* 415 * There should actually be 0 here. 416 * Just ignore the error. 417 */ 418 scn = MSDOSFSROOT; 419 } 420 } 421 422 if (isadir) { 423 cluster = scn; 424 if (cluster == MSDOSFSROOT) 425 blkoff = MSDOSFSROOT_OFS; 426 else 427 blkoff = 0; 428 } else if (cluster == MSDOSFSROOT) 429 blkoff = diroff; 430 431 /* 432 * Now release buf to allow deget to read the entry again. 433 * Reserving it here and giving it to deget could result 434 * in a deadlock. 435 */ 436 brelse(bp); 437 bp = NULL; 438 439 foundroot: 440 /* 441 * If we entered at foundroot, then we are looking for the . or .. 442 * entry of the filesystems root directory. isadir and scn were 443 * setup before jumping here. And, bp is already null. 444 */ 445 if (FAT32(pmp) && scn == MSDOSFSROOT) 446 scn = pmp->pm_rootdirblk; 447 448 /* 449 * If deleting, and at end of pathname, return 450 * parameters which can be used to remove file. 451 * If the wantparent flag isn't set, we return only 452 * the directory (in ndp->ni_dvp), otherwise we go 453 * on and lock the inode, being careful with ".". 454 */ 455 if (nameiop == NAMEI_DELETE) { 456 /* 457 * Don't allow deleting the root. 458 */ 459 if (blkoff == MSDOSFSROOT_OFS) 460 return (EBUSY); 461 462 /* 463 * Write access to directory required to delete files. 464 */ 465 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred); 466 if (error) 467 return (error); 468 469 /* 470 * Return pointer to current entry in dp->i_offset. 471 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 472 */ 473 if (dp->de_StartCluster == scn && isadir) { /* "." */ 474 vref(vdp); 475 *vpp = vdp; 476 return (0); 477 } 478 error = deget(pmp, cluster, blkoff, &tdp); 479 if (error) 480 return (error); 481 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp); 482 if (!lockparent) { 483 vn_unlock(vdp); 484 cnp->cn_flags |= CNP_PDIRUNLOCK; 485 } 486 return (error); 487 } 488 489 /* 490 * If rewriting (RENAME), return the inode and the 491 * information required to rewrite the present directory 492 * Must get inode of directory entry to verify it's a 493 * regular file, or empty directory. 494 */ 495 if (nameiop == NAMEI_RENAME && wantparent) { 496 if (blkoff == MSDOSFSROOT_OFS) 497 return (EBUSY); 498 499 error = VOP_EACCESS(vdp, VWRITE, cnp->cn_cred); 500 if (error) 501 return (error); 502 503 /* 504 * Careful about locking second inode. 505 * This can only occur if the target is ".". 506 */ 507 if (dp->de_StartCluster == scn && isadir) 508 return (EISDIR); 509 510 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 511 return (error); 512 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp); 513 if (!lockparent) { 514 vn_unlock(vdp); 515 cnp->cn_flags |= CNP_PDIRUNLOCK; 516 } 517 return (error); 518 } 519 520 /* 521 * Step through the translation in the name. We do not `vput' the 522 * directory because we may need it again if a symbolic link 523 * is relative to the current directory. Instead we save it 524 * unlocked as "pdp". We must get the target inode before unlocking 525 * the directory to insure that the inode will not be removed 526 * before we get it. We prevent deadlock by always fetching 527 * inodes from the root, moving down the directory tree. Thus 528 * when following backward pointers ".." we must unlock the 529 * parent directory before getting the requested directory. 530 * There is a potential race condition here if both the current 531 * and parent directories are removed before the VFS_VGET for the 532 * inode associated with ".." returns. We hope that this occurs 533 * infrequently since we cannot avoid this race condition without 534 * implementing a sophisticated deadlock detection algorithm. 535 * Note also that this simple deadlock detection scheme will not 536 * work if the file system has any hard links other than ".." 537 * that point backwards in the directory structure. 538 */ 539 pdp = vdp; 540 if (flags & CNP_ISDOTDOT) { 541 vn_unlock(pdp); 542 cnp->cn_flags |= CNP_PDIRUNLOCK; 543 error = deget(pmp, cluster, blkoff, &tdp); 544 if (error) { 545 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY); 546 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 547 return (error); 548 } 549 if (lockparent) { 550 error = vn_lock(pdp, LK_EXCLUSIVE | LK_FAILRECLAIM); 551 if (error) { 552 vput(DETOV(tdp)); 553 return (error); 554 } 555 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 556 } 557 error = msdosfs_lookup_checker(pmp, vdp, VTODE(*vpp), vpp); 558 if (error != 0) 559 return (error); 560 } else if (dp->de_StartCluster == scn && isadir) { 561 if (cnp->cn_namelen != 1 || cnp->cn_nameptr[0] != '.') { 562 /* fs is corrupted, non-dot lookup returned dvp */ 563 return (EBADF); 564 } 565 vref(vdp); /* we want ourself, ie "." */ 566 *vpp = vdp; 567 } else { 568 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 569 return (error); 570 if (!lockparent) { 571 vn_unlock(pdp); 572 cnp->cn_flags |= CNP_PDIRUNLOCK; 573 } 574 error = msdosfs_lookup_checker(pmp, vdp, tdp, vpp); 575 if (error != 0) 576 return (error); 577 } 578 return (0); 579 } 580 581 /* 582 * dep - directory entry to copy into the directory 583 * ddep - directory to add to 584 * depp - return the address of the denode for the created directory entry 585 * if depp != 0 586 * cnp - componentname needed for Win95 long filenames 587 */ 588 int 589 createde(struct denode *dep, struct denode *ddep, struct denode **depp, 590 struct componentname *cnp) 591 { 592 int error; 593 u_long dirclust, diroffset; 594 struct direntry *ndep; 595 struct msdosfsmount *pmp = ddep->de_pmp; 596 struct buf *bp; 597 daddr_t bn; 598 int blsize; 599 600 mprintf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 601 dep, ddep, depp, cnp); 602 603 /* 604 * If no space left in the directory then allocate another cluster 605 * and chain it onto the end of the file. There is one exception 606 * to this. That is, if the root directory has no more space it 607 * can NOT be expanded. extendfile() checks for and fails attempts 608 * to extend the root directory. We just return an error in that 609 * case. 610 */ 611 if (ddep->de_fndoffset >= ddep->de_FileSize) { 612 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 613 - ddep->de_FileSize; 614 dirclust = de_clcount(pmp, diroffset); 615 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 616 if (error) { 617 detrunc(ddep, ddep->de_FileSize, 0); 618 return error; 619 } 620 621 /* 622 * Update the size of the directory 623 */ 624 ddep->de_FileSize += de_cn2off(pmp, dirclust); 625 } 626 627 /* 628 * We just read in the cluster with space. Copy the new directory 629 * entry in. Then write it to disk. NOTE: DOS directories 630 * do not get smaller as clusters are emptied. 631 */ 632 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 633 &bn, &dirclust, &blsize); 634 if (error) 635 return error; 636 diroffset = ddep->de_fndoffset; 637 if (dirclust != MSDOSFSROOT) 638 diroffset &= pmp->pm_crbomask; 639 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp); 640 if (error != 0) { 641 brelse(bp); 642 return error; 643 } 644 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 645 646 DE_EXTERNALIZE(ndep, dep); 647 648 /* 649 * Now write the Win95 long name 650 */ 651 if (ddep->de_fndcnt > 0) { 652 uint8_t chksum = winChksum(ndep->deName); 653 const u_char *un = (const u_char *)cnp->cn_nameptr; 654 int unlen = cnp->cn_namelen; 655 int cnt = 1; 656 657 while (--ddep->de_fndcnt >= 0) { 658 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 659 if (DOINGASYNC(DETOV(ddep))) 660 bdwrite(bp); 661 else if ((error = bwrite(bp)) != 0) 662 return error; 663 664 ddep->de_fndoffset -= sizeof(struct direntry); 665 error = pcbmap(ddep, 666 de_cluster(pmp, 667 ddep->de_fndoffset), 668 &bn, NULL, &blsize); 669 if (error) 670 return error; 671 672 error = bread(pmp->pm_devvp, 673 de_bn2doff(pmp, bn), blsize, 674 &bp); 675 if (error) { 676 brelse(bp); 677 return error; 678 } 679 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 680 } else { 681 ndep--; 682 ddep->de_fndoffset -= sizeof(struct direntry); 683 } 684 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 685 cnt++, chksum, pmp)) 686 break; 687 } 688 } 689 690 if (DOINGASYNC(DETOV(ddep))) 691 bdwrite(bp); 692 else if ((error = bwrite(bp)) != 0) 693 return error; 694 695 /* 696 * If they want us to return with the denode gotten. 697 */ 698 if (depp) { 699 if (dep->de_Attributes & ATTR_DIRECTORY) { 700 dirclust = dep->de_StartCluster; 701 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 702 dirclust = MSDOSFSROOT; 703 if (dirclust == MSDOSFSROOT) 704 diroffset = MSDOSFSROOT_OFS; 705 else 706 diroffset = 0; 707 } 708 return deget(pmp, dirclust, diroffset, depp); 709 } 710 711 return 0; 712 } 713 714 /* 715 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 716 * return 0 if not empty or error. 717 */ 718 int 719 dosdirempty(struct denode *dep) 720 { 721 int blsize; 722 int error; 723 u_long cn; 724 daddr_t bn; 725 struct buf *bp; 726 struct msdosfsmount *pmp = dep->de_pmp; 727 struct direntry *dentp; 728 729 /* 730 * Since the filesize field in directory entries for a directory is 731 * zero, we just have to feel our way through the directory until 732 * we hit end of file. 733 */ 734 for (cn = 0;; cn++) { 735 if ((error = pcbmap(dep, cn, &bn, NULL, &blsize)) != 0) { 736 if (error == E2BIG) 737 return (1); /* it's empty */ 738 return (0); 739 } 740 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp); 741 if (error) { 742 brelse(bp); 743 return (0); 744 } 745 for (dentp = (struct direntry *)bp->b_data; 746 (char *)dentp < bp->b_data + blsize; 747 dentp++) { 748 if (dentp->deName[0] != SLOT_DELETED && 749 (dentp->deAttributes & ATTR_VOLUME) == 0) { 750 /* 751 * In dos directories an entry whose name 752 * starts with SLOT_EMPTY (0) starts the 753 * beginning of the unused part of the 754 * directory, so we can just return that it 755 * is empty. 756 */ 757 if (dentp->deName[0] == SLOT_EMPTY) { 758 brelse(bp); 759 return (1); 760 } 761 /* 762 * Any names other than "." and ".." in a 763 * directory mean it is not empty. 764 */ 765 if (memcmp(dentp->deName, ". ", 11) && 766 memcmp(dentp->deName, ".. ", 11)) { 767 brelse(bp); 768 mprintf("dosdirempty(): entry found %02x, %02x\n", 769 dentp->deName[0], dentp->deName[1]); 770 return (0); /* not empty */ 771 } 772 } 773 } 774 brelse(bp); 775 } 776 /* NOTREACHED */ 777 } 778 779 /* 780 * Check to see if the directory described by target is in some 781 * subdirectory of source. This prevents something like the following from 782 * succeeding and leaving a bunch or files and directories orphaned. mv 783 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 784 * 785 * source - the inode for /a/b/c 786 * target - the inode for /a/b/c/d/e/f 787 * 788 * Returns 0 if target is NOT a subdirectory of source. 789 * Otherwise returns a non-zero error number. 790 * The target inode is always unlocked on return. 791 */ 792 int 793 doscheckpath(struct denode *source, struct denode *target) 794 { 795 daddr_t scn; 796 struct msdosfsmount *pmp; 797 struct direntry *ep; 798 struct denode *dep; 799 struct buf *bp = NULL; 800 int error = 0; 801 802 dep = target; 803 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 804 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 805 error = ENOTDIR; 806 goto out; 807 } 808 if (dep->de_StartCluster == source->de_StartCluster) { 809 error = EEXIST; 810 goto out; 811 } 812 if (dep->de_StartCluster == MSDOSFSROOT) 813 goto out; 814 pmp = dep->de_pmp; 815 #ifdef DIAGNOSTIC 816 if (pmp != source->de_pmp) 817 panic("doscheckpath: source and target on different filesystems"); 818 #endif 819 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 820 goto out; 821 822 for (;;) { 823 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 824 error = ENOTDIR; 825 break; 826 } 827 scn = dep->de_StartCluster; 828 error = bread(pmp->pm_devvp, de_bn2doff(pmp, cntobn(pmp, scn)), 829 pmp->pm_bpcluster, &bp); 830 if (error) 831 break; 832 833 ep = (struct direntry *) bp->b_data + 1; 834 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 835 memcmp(ep->deName, ".. ", 11) != 0) { 836 error = ENOTDIR; 837 break; 838 } 839 scn = getushort(ep->deStartCluster); 840 if (FAT32(pmp)) 841 scn |= getushort(ep->deHighClust) << 16; 842 843 if (scn == source->de_StartCluster) { 844 error = EINVAL; 845 break; 846 } 847 if (scn == MSDOSFSROOT) 848 break; 849 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 850 /* 851 * scn should be 0 in this case, 852 * but we silently ignore the error. 853 */ 854 break; 855 } 856 857 vput(DETOV(dep)); 858 brelse(bp); 859 bp = NULL; 860 /* NOTE: deget() clears dep on error */ 861 if ((error = deget(pmp, scn, 0, &dep)) != 0) 862 break; 863 } 864 out: 865 if (bp) 866 brelse(bp); 867 if (error == ENOTDIR) 868 kprintf("doscheckpath(): .. not a directory?\n"); 869 if (dep != NULL) 870 vput(DETOV(dep)); 871 return (error); 872 } 873 874 /* 875 * Read in the disk block containing the directory entry (dirclu, dirofs) 876 * and return the address of the buf header, and the address of the 877 * directory entry within the block. 878 */ 879 int 880 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 881 struct buf **bpp, struct direntry **epp) 882 { 883 int error; 884 daddr_t bn; 885 int blsize; 886 887 blsize = pmp->pm_bpcluster; 888 if (dirclust == MSDOSFSROOT 889 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 890 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 891 bn = detobn(pmp, dirclust, diroffset); 892 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, bpp); 893 if (error != 0) { 894 brelse(*bpp); 895 *bpp = NULL; 896 return (error); 897 } 898 if (epp) 899 *epp = bptoep(pmp, *bpp, diroffset); 900 return (0); 901 } 902 903 /* 904 * Read in the disk block containing the directory entry dep came from and 905 * return the address of the buf header, and the address of the directory 906 * entry within the block. 907 */ 908 int 909 readde(struct denode *dep, struct buf **bpp, struct direntry **epp) 910 { 911 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 912 bpp, epp)); 913 } 914 915 /* 916 * Remove a directory entry. At this point the file represented by the 917 * directory entry to be removed is still full length until no one has it 918 * open. When the file no longer being used msdosfs_inactive() is called 919 * and will truncate the file to 0 length. When the vnode containing the 920 * denode is needed for some other purpose by VFS it will call 921 * msdosfs_reclaim() which will remove the denode from the denode cache. 922 * 923 * pdep directory where the entry is removed 924 * dep file to be removed 925 */ 926 int 927 removede(struct denode *pdep, struct denode *dep) 928 { 929 int error; 930 struct direntry *ep; 931 struct buf *bp; 932 daddr_t bn; 933 int blsize; 934 struct msdosfsmount *pmp = pdep->de_pmp; 935 u_long offset = pdep->de_fndoffset; 936 937 mprintf("removede(): filename %s, dep %p, offset %08lx\n", 938 dep->de_Name, dep, offset); 939 940 KKASSERT(dep->de_refcnt > 0); 941 dep->de_refcnt--; 942 offset += sizeof(struct direntry); 943 do { 944 offset -= sizeof(struct direntry); 945 error = pcbmap(pdep, de_cluster(pmp, offset), 946 &bn, NULL, &blsize); 947 if (error) 948 return error; 949 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), blsize, &bp); 950 if (error) { 951 brelse(bp); 952 return error; 953 } 954 ep = bptoep(pmp, bp, offset); 955 /* 956 * Check whether, if we came here the second time, i.e. 957 * when underflowing into the previous block, the last 958 * entry in this block is a longfilename entry, too. 959 */ 960 if (ep->deAttributes != ATTR_WIN95 961 && offset != pdep->de_fndoffset) { 962 brelse(bp); 963 break; 964 } 965 offset += sizeof(struct direntry); 966 while (1) { 967 /* 968 * We are a bit aggressive here in that we delete any Win95 969 * entries preceding this entry, not just the ones we "own". 970 * Since these presumably aren't valid anyway, 971 * there should be no harm. 972 */ 973 offset -= sizeof(struct direntry); 974 ep--->deName[0] = SLOT_DELETED; 975 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 976 || !(offset & pmp->pm_crbomask) 977 || ep->deAttributes != ATTR_WIN95) 978 break; 979 } 980 if (DOINGASYNC(DETOV(pdep))) 981 bdwrite(bp); 982 else if ((error = bwrite(bp)) != 0) 983 return error; 984 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 985 && !(offset & pmp->pm_crbomask) 986 && offset); 987 return 0; 988 } 989 990 /* 991 * Create a unique DOS name in dvp 992 */ 993 int 994 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp) 995 { 996 struct msdosfsmount *pmp = dep->de_pmp; 997 struct direntry *dentp; 998 int gen; 999 int blsize; 1000 u_long cn; 1001 daddr_t bn; 1002 struct buf *bp; 1003 int error; 1004 1005 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 1006 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 1007 cnp->cn_namelen, 0, pmp) ? 0 : EINVAL); 1008 1009 for (gen = 1;; gen++) { 1010 /* 1011 * Generate DOS name with generation number 1012 */ 1013 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 1014 cnp->cn_namelen, gen, pmp)) 1015 return gen == 1 ? EINVAL : EEXIST; 1016 1017 /* 1018 * Now look for a dir entry with this exact name 1019 */ 1020 for (cn = error = 0; !error; cn++) { 1021 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 1022 if (error == E2BIG) /* EOF reached and not found */ 1023 return 0; 1024 return error; 1025 } 1026 error = bread(pmp->pm_devvp, de_bn2doff(pmp, bn), 1027 blsize, &bp); 1028 if (error) { 1029 brelse(bp); 1030 return error; 1031 } 1032 for (dentp = (struct direntry *)bp->b_data; 1033 (char *)dentp < bp->b_data + blsize; 1034 dentp++) { 1035 if (dentp->deName[0] == SLOT_EMPTY) { 1036 /* 1037 * Last used entry and not found 1038 */ 1039 brelse(bp); 1040 return 0; 1041 } 1042 /* 1043 * Ignore volume labels and Win95 entries 1044 */ 1045 if (dentp->deAttributes & ATTR_VOLUME) 1046 continue; 1047 if (!memcmp(dentp->deName, cp, 11)) { 1048 error = EEXIST; 1049 break; 1050 } 1051 } 1052 brelse(bp); 1053 } 1054 } 1055 } 1056