1 /* $FreeBSD: src/sys/msdosfs/msdosfs_lookup.c,v 1.30.2.1 2000/11/03 15:55:39 bp Exp $ */ 2 /* $DragonFly: src/sys/vfs/msdosfs/msdosfs_lookup.c,v 1.10 2004/04/24 04:32:04 drhodus Exp $ */ 3 /* $NetBSD: msdosfs_lookup.c,v 1.37 1997/11/17 15:36:54 ws Exp $ */ 4 5 /*- 6 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 7 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 8 * All rights reserved. 9 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by TooLs GmbH. 22 * 4. The name of TooLs GmbH may not be used to endorse or promote products 23 * derived from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 30 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 31 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 32 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 33 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 34 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 /* 37 * Written by Paul Popelka (paulp@uts.amdahl.com) 38 * 39 * You can do anything you want with this software, just don't say you wrote 40 * it, and don't remove this notice. 41 * 42 * This software is provided "as is". 43 * 44 * The author supplies this software to be publicly redistributed on the 45 * understanding that the author is not responsible for the correct 46 * functioning of this software in any circumstances and is not liable for 47 * any damages caused by this software. 48 * 49 * October 1992 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/buf.h> 55 #include <sys/vnode.h> 56 #include <sys/proc.h> 57 #include <sys/namei.h> 58 #include <sys/mount.h> 59 60 #include "bpb.h" 61 #include "direntry.h" 62 #include "denode.h" 63 #include "msdosfsmount.h" 64 #include "fat.h" 65 66 /* 67 * When we search a directory the blocks containing directory entries are 68 * read and examined. The directory entries contain information that would 69 * normally be in the inode of a unix filesystem. This means that some of 70 * a directory's contents may also be in memory resident denodes (sort of 71 * an inode). This can cause problems if we are searching while some other 72 * process is modifying a directory. To prevent one process from accessing 73 * incompletely modified directory information we depend upon being the 74 * sole owner of a directory block. bread/brelse provide this service. 75 * This being the case, when a process modifies a directory it must first 76 * acquire the disk block that contains the directory entry to be modified. 77 * Then update the disk block and the denode, and then write the disk block 78 * out to disk. This way disk blocks containing directory entries and in 79 * memory denode's will be in synch. 80 * 81 * msdosfs_lookup(struct vnode *a_dvp, struct vnode **a_vpp, 82 * struct componentname *a_cnp) 83 */ 84 int 85 msdosfs_lookup(struct vop_cachedlookup_args *ap) 86 { 87 struct vnode *vdp = ap->a_dvp; 88 struct vnode **vpp = ap->a_vpp; 89 struct componentname *cnp = ap->a_cnp; 90 daddr_t bn; 91 int error; 92 int lockparent; 93 int wantparent; 94 int slotcount; 95 int slotoffset = 0; 96 int frcn; 97 u_long cluster; 98 int blkoff; 99 int diroff; 100 int blsize; 101 int isadir; /* ~0 if found direntry is a directory */ 102 u_long scn; /* starting cluster number */ 103 struct vnode *pdp; 104 struct denode *dp; 105 struct denode *tdp; 106 struct msdosfsmount *pmp; 107 struct buf *bp = 0; 108 struct direntry *dep = NULL; 109 u_char dosfilename[12]; 110 int flags = cnp->cn_flags; 111 int nameiop = cnp->cn_nameiop; 112 struct thread *td = cnp->cn_td; 113 int unlen; 114 115 int wincnt = 1; 116 int chksum = -1; 117 int olddos = 1; 118 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 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 & CNP_LOCKPARENT; 127 wantparent = flags & (CNP_LOCKPARENT | CNP_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 == NAMEI_CREATE || nameiop == NAMEI_RENAME) && 183 (flags & CNP_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, &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++) */ 307 308 notfound: 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 == NAMEI_CREATE || nameiop == NAMEI_RENAME) && 337 (flags & CNP_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_td); 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 |= CNP_SAVENAME; 366 if (!lockparent) { 367 VOP_UNLOCK(vdp, NULL, 0, td); 368 cnp->cn_flags |= CNP_PDIRUNLOCK; 369 } 370 return (EJUSTRETURN); 371 } 372 /* 373 * Insert name into cache (as non-existent) if appropriate. 374 */ 375 if ((cnp->cn_flags & CNP_MAKEENTRY) && nameiop != NAMEI_CREATE) 376 cache_enter(vdp, NCPNULL, *vpp, cnp); 377 return (ENOENT); 378 379 found: 380 /* 381 * NOTE: We still have the buffer with matched directory entry at 382 * this point. 383 */ 384 isadir = dep->deAttributes & ATTR_DIRECTORY; 385 scn = getushort(dep->deStartCluster); 386 if (FAT32(pmp)) { 387 scn |= getushort(dep->deHighClust) << 16; 388 if (scn == pmp->pm_rootdirblk) { 389 /* 390 * There should actually be 0 here. 391 * Just ignore the error. 392 */ 393 scn = MSDOSFSROOT; 394 } 395 } 396 397 if (isadir) { 398 cluster = scn; 399 if (cluster == MSDOSFSROOT) 400 blkoff = MSDOSFSROOT_OFS; 401 else 402 blkoff = 0; 403 } else if (cluster == MSDOSFSROOT) 404 blkoff = diroff; 405 406 /* 407 * Now release buf to allow deget to read the entry again. 408 * Reserving it here and giving it to deget could result 409 * in a deadlock. 410 */ 411 brelse(bp); 412 bp = 0; 413 414 foundroot: 415 /* 416 * If we entered at foundroot, then we are looking for the . or .. 417 * entry of the filesystems root directory. isadir and scn were 418 * setup before jumping here. And, bp is already null. 419 */ 420 if (FAT32(pmp) && scn == MSDOSFSROOT) 421 scn = pmp->pm_rootdirblk; 422 423 /* 424 * If deleting, and at end of pathname, return 425 * parameters which can be used to remove file. 426 * If the wantparent flag isn't set, we return only 427 * the directory (in ndp->ni_dvp), otherwise we go 428 * on and lock the inode, being careful with ".". 429 */ 430 if (nameiop == NAMEI_DELETE && (flags & CNP_ISLASTCN)) { 431 /* 432 * Don't allow deleting the root. 433 */ 434 if (blkoff == MSDOSFSROOT_OFS) 435 return EROFS; /* really? XXX */ 436 437 /* 438 * Write access to directory required to delete files. 439 */ 440 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_td); 441 if (error) 442 return (error); 443 444 /* 445 * Return pointer to current entry in dp->i_offset. 446 * Save directory inode pointer in ndp->ni_dvp for dirremove(). 447 */ 448 if (dp->de_StartCluster == scn && isadir) { /* "." */ 449 vref(vdp); 450 *vpp = vdp; 451 return (0); 452 } 453 error = deget(pmp, cluster, blkoff, &tdp); 454 if (error) 455 return (error); 456 *vpp = DETOV(tdp); 457 if (!lockparent) { 458 VOP_UNLOCK(vdp, NULL, 0, td); 459 cnp->cn_flags |= CNP_PDIRUNLOCK; 460 } 461 return (0); 462 } 463 464 /* 465 * If rewriting (RENAME), return the inode and the 466 * information required to rewrite the present directory 467 * Must get inode of directory entry to verify it's a 468 * regular file, or empty directory. 469 */ 470 if (nameiop == NAMEI_RENAME && wantparent && 471 (flags & CNP_ISLASTCN)) { 472 if (blkoff == MSDOSFSROOT_OFS) 473 return EROFS; /* really? XXX */ 474 475 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_td); 476 if (error) 477 return (error); 478 479 /* 480 * Careful about locking second inode. 481 * This can only occur if the target is ".". 482 */ 483 if (dp->de_StartCluster == scn && isadir) 484 return (EISDIR); 485 486 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 487 return (error); 488 *vpp = DETOV(tdp); 489 cnp->cn_flags |= CNP_SAVENAME; 490 if (!lockparent) { 491 VOP_UNLOCK(vdp, NULL, 0, td); 492 cnp->cn_flags |= CNP_PDIRUNLOCK; 493 } 494 return (0); 495 } 496 497 /* 498 * Step through the translation in the name. We do not `vput' the 499 * directory because we may need it again if a symbolic link 500 * is relative to the current directory. Instead we save it 501 * unlocked as "pdp". We must get the target inode before unlocking 502 * the directory to insure that the inode will not be removed 503 * before we get it. We prevent deadlock by always fetching 504 * inodes from the root, moving down the directory tree. Thus 505 * when following backward pointers ".." we must unlock the 506 * parent directory before getting the requested directory. 507 * There is a potential race condition here if both the current 508 * and parent directories are removed before the VFS_VGET for the 509 * inode associated with ".." returns. We hope that this occurs 510 * infrequently since we cannot avoid this race condition without 511 * implementing a sophisticated deadlock detection algorithm. 512 * Note also that this simple deadlock detection scheme will not 513 * work if the file system has any hard links other than ".." 514 * that point backwards in the directory structure. 515 */ 516 pdp = vdp; 517 if (flags & CNP_ISDOTDOT) { 518 VOP_UNLOCK(pdp, NULL, 0, td); 519 cnp->cn_flags |= CNP_PDIRUNLOCK; 520 error = deget(pmp, cluster, blkoff, &tdp); 521 if (error) { 522 vn_lock(pdp, NULL, LK_EXCLUSIVE | LK_RETRY, td); 523 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 524 return (error); 525 } 526 if (lockparent && (flags & CNP_ISLASTCN)) { 527 error = vn_lock(pdp, NULL, LK_EXCLUSIVE, td); 528 if (error) { 529 vput(DETOV(tdp)); 530 return (error); 531 } 532 cnp->cn_flags &= ~CNP_PDIRUNLOCK; 533 } 534 *vpp = DETOV(tdp); 535 } else if (dp->de_StartCluster == scn && isadir) { 536 vref(vdp); /* we want ourself, ie "." */ 537 *vpp = vdp; 538 } else { 539 if ((error = deget(pmp, cluster, blkoff, &tdp)) != 0) 540 return (error); 541 if (!lockparent || !(flags & CNP_ISLASTCN)) { 542 VOP_UNLOCK(pdp, NULL, 0, td); 543 cnp->cn_flags |= CNP_PDIRUNLOCK; 544 } 545 *vpp = DETOV(tdp); 546 } 547 548 /* 549 * Insert name into cache if appropriate. 550 */ 551 if (cnp->cn_flags & CNP_MAKEENTRY) 552 cache_enter(vdp, NCPNULL, *vpp, cnp); 553 return (0); 554 } 555 556 /* 557 * dep - directory entry to copy into the directory 558 * ddep - directory to add to 559 * depp - return the address of the denode for the created directory entry 560 * if depp != 0 561 * cnp - componentname needed for Win95 long filenames 562 */ 563 int 564 createde(struct denode *dep, struct denode *ddep, struct denode **depp, 565 struct componentname *cnp) 566 { 567 int error; 568 u_long dirclust, diroffset; 569 struct direntry *ndep; 570 struct msdosfsmount *pmp = ddep->de_pmp; 571 struct buf *bp; 572 daddr_t bn; 573 int blsize; 574 575 #ifdef MSDOSFS_DEBUG 576 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 577 dep, ddep, depp, cnp); 578 #endif 579 580 /* 581 * If no space left in the directory then allocate another cluster 582 * and chain it onto the end of the file. There is one exception 583 * to this. That is, if the root directory has no more space it 584 * can NOT be expanded. extendfile() checks for and fails attempts 585 * to extend the root directory. We just return an error in that 586 * case. 587 */ 588 if (ddep->de_fndoffset >= ddep->de_FileSize) { 589 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 590 - ddep->de_FileSize; 591 dirclust = de_clcount(pmp, diroffset); 592 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 593 if (error) { 594 (void)detrunc(ddep, ddep->de_FileSize, 0, NULL); 595 return error; 596 } 597 598 /* 599 * Update the size of the directory 600 */ 601 ddep->de_FileSize += de_cn2off(pmp, dirclust); 602 } 603 604 /* 605 * We just read in the cluster with space. Copy the new directory 606 * entry in. Then write it to disk. NOTE: DOS directories 607 * do not get smaller as clusters are emptied. 608 */ 609 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 610 &bn, &dirclust, &blsize); 611 if (error) 612 return error; 613 diroffset = ddep->de_fndoffset; 614 if (dirclust != MSDOSFSROOT) 615 diroffset &= pmp->pm_crbomask; 616 if ((error = bread(pmp->pm_devvp, bn, blsize, &bp)) != 0) { 617 brelse(bp); 618 return error; 619 } 620 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 621 622 DE_EXTERNALIZE(ndep, dep); 623 624 /* 625 * Now write the Win95 long name 626 */ 627 if (ddep->de_fndcnt > 0) { 628 u_int8_t chksum = winChksum(ndep->deName); 629 const u_char *un = (const u_char *)cnp->cn_nameptr; 630 int unlen = cnp->cn_namelen; 631 int cnt = 1; 632 633 while (--ddep->de_fndcnt >= 0) { 634 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 635 if ((error = bwrite(bp)) != 0) 636 return error; 637 638 ddep->de_fndoffset -= sizeof(struct direntry); 639 error = pcbmap(ddep, 640 de_cluster(pmp, 641 ddep->de_fndoffset), 642 &bn, 0, &blsize); 643 if (error) 644 return error; 645 646 error = bread(pmp->pm_devvp, bn, blsize, &bp); 647 if (error) { 648 brelse(bp); 649 return error; 650 } 651 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 652 } else { 653 ndep--; 654 ddep->de_fndoffset -= sizeof(struct direntry); 655 } 656 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 657 cnt++, chksum, 658 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 659 pmp->pm_u2w)) 660 break; 661 } 662 } 663 664 if ((error = bwrite(bp)) != 0) 665 return error; 666 667 /* 668 * If they want us to return with the denode gotten. 669 */ 670 if (depp) { 671 if (dep->de_Attributes & ATTR_DIRECTORY) { 672 dirclust = dep->de_StartCluster; 673 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 674 dirclust = MSDOSFSROOT; 675 if (dirclust == MSDOSFSROOT) 676 diroffset = MSDOSFSROOT_OFS; 677 else 678 diroffset = 0; 679 } 680 return deget(pmp, dirclust, diroffset, depp); 681 } 682 683 return 0; 684 } 685 686 /* 687 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 688 * return 0 if not empty or error. 689 */ 690 int 691 dosdirempty(struct denode *dep) 692 { 693 int blsize; 694 int error; 695 u_long cn; 696 daddr_t bn; 697 struct buf *bp; 698 struct msdosfsmount *pmp = dep->de_pmp; 699 struct direntry *dentp; 700 701 /* 702 * Since the filesize field in directory entries for a directory is 703 * zero, we just have to feel our way through the directory until 704 * we hit end of file. 705 */ 706 for (cn = 0;; cn++) { 707 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 708 if (error == E2BIG) 709 return (1); /* it's empty */ 710 return (0); 711 } 712 error = bread(pmp->pm_devvp, bn, blsize, &bp); 713 if (error) { 714 brelse(bp); 715 return (0); 716 } 717 for (dentp = (struct direntry *)bp->b_data; 718 (char *)dentp < bp->b_data + blsize; 719 dentp++) { 720 if (dentp->deName[0] != SLOT_DELETED && 721 (dentp->deAttributes & ATTR_VOLUME) == 0) { 722 /* 723 * In dos directories an entry whose name 724 * starts with SLOT_EMPTY (0) starts the 725 * beginning of the unused part of the 726 * directory, so we can just return that it 727 * is empty. 728 */ 729 if (dentp->deName[0] == SLOT_EMPTY) { 730 brelse(bp); 731 return (1); 732 } 733 /* 734 * Any names other than "." and ".." in a 735 * directory mean it is not empty. 736 */ 737 if (bcmp(dentp->deName, ". ", 11) && 738 bcmp(dentp->deName, ".. ", 11)) { 739 brelse(bp); 740 #ifdef MSDOSFS_DEBUG 741 printf("dosdirempty(): entry found %02x, %02x\n", 742 dentp->deName[0], dentp->deName[1]); 743 #endif 744 return (0); /* not empty */ 745 } 746 } 747 } 748 brelse(bp); 749 } 750 /* NOTREACHED */ 751 } 752 753 /* 754 * Check to see if the directory described by target is in some 755 * subdirectory of source. This prevents something like the following from 756 * succeeding and leaving a bunch or files and directories orphaned. mv 757 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 758 * 759 * source - the inode for /a/b/c 760 * target - the inode for /a/b/c/d/e/f 761 * 762 * Returns 0 if target is NOT a subdirectory of source. 763 * Otherwise returns a non-zero error number. 764 * The target inode is always unlocked on return. 765 */ 766 int 767 doscheckpath(struct denode *source, struct denode *target) 768 { 769 daddr_t scn; 770 struct msdosfsmount *pmp; 771 struct direntry *ep; 772 struct denode *dep; 773 struct buf *bp = NULL; 774 int error = 0; 775 776 dep = target; 777 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 778 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 779 error = ENOTDIR; 780 goto out; 781 } 782 if (dep->de_StartCluster == source->de_StartCluster) { 783 error = EEXIST; 784 goto out; 785 } 786 if (dep->de_StartCluster == MSDOSFSROOT) 787 goto out; 788 pmp = dep->de_pmp; 789 #ifdef DIAGNOSTIC 790 if (pmp != source->de_pmp) 791 panic("doscheckpath: source and target on different filesystems"); 792 #endif 793 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 794 goto out; 795 796 for (;;) { 797 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 798 error = ENOTDIR; 799 break; 800 } 801 scn = dep->de_StartCluster; 802 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 803 pmp->pm_bpcluster, &bp); 804 if (error) 805 break; 806 807 ep = (struct direntry *) bp->b_data + 1; 808 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 809 bcmp(ep->deName, ".. ", 11) != 0) { 810 error = ENOTDIR; 811 break; 812 } 813 scn = getushort(ep->deStartCluster); 814 if (FAT32(pmp)) 815 scn |= getushort(ep->deHighClust) << 16; 816 817 if (scn == source->de_StartCluster) { 818 error = EINVAL; 819 break; 820 } 821 if (scn == MSDOSFSROOT) 822 break; 823 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 824 /* 825 * scn should be 0 in this case, 826 * but we silently ignore the error. 827 */ 828 break; 829 } 830 831 vput(DETOV(dep)); 832 brelse(bp); 833 bp = NULL; 834 /* NOTE: deget() clears dep on error */ 835 if ((error = deget(pmp, scn, 0, &dep)) != 0) 836 break; 837 } 838 out:; 839 if (bp) 840 brelse(bp); 841 if (error == ENOTDIR) 842 printf("doscheckpath(): .. not a directory?\n"); 843 if (dep != NULL) 844 vput(DETOV(dep)); 845 return (error); 846 } 847 848 /* 849 * Read in the disk block containing the directory entry (dirclu, dirofs) 850 * and return the address of the buf header, and the address of the 851 * directory entry within the block. 852 */ 853 int 854 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, 855 struct buf **bpp, struct direntry **epp) 856 { 857 int error; 858 daddr_t bn; 859 int blsize; 860 861 blsize = pmp->pm_bpcluster; 862 if (dirclust == MSDOSFSROOT 863 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 864 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 865 bn = detobn(pmp, dirclust, diroffset); 866 if ((error = bread(pmp->pm_devvp, bn, blsize, bpp)) != 0) { 867 brelse(*bpp); 868 *bpp = NULL; 869 return (error); 870 } 871 if (epp) 872 *epp = bptoep(pmp, *bpp, diroffset); 873 return (0); 874 } 875 876 /* 877 * Read in the disk block containing the directory entry dep came from and 878 * return the address of the buf header, and the address of the directory 879 * entry within the block. 880 */ 881 int 882 readde(struct denode *dep, struct buf **bpp, struct direntry **epp) 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 */ 896 int 897 removede(struct denode *pdep, /* directory where the entry is removed */ 898 struct denode *dep) /* file to be removed */ 899 { 900 int error; 901 struct direntry *ep; 902 struct buf *bp; 903 daddr_t bn; 904 int blsize; 905 struct msdosfsmount *pmp = pdep->de_pmp; 906 u_long offset = pdep->de_fndoffset; 907 908 #ifdef MSDOSFS_DEBUG 909 printf("removede(): filename %s, dep %p, offset %08lx\n", 910 dep->de_Name, dep, offset); 911 #endif 912 913 dep->de_refcnt--; 914 offset += sizeof(struct direntry); 915 do { 916 offset -= sizeof(struct direntry); 917 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 918 if (error) 919 return error; 920 error = bread(pmp->pm_devvp, bn, blsize, &bp); 921 if (error) { 922 brelse(bp); 923 return error; 924 } 925 ep = bptoep(pmp, bp, offset); 926 /* 927 * Check whether, if we came here the second time, i.e. 928 * when underflowing into the previous block, the last 929 * entry in this block is a longfilename entry, too. 930 */ 931 if (ep->deAttributes != ATTR_WIN95 932 && offset != pdep->de_fndoffset) { 933 brelse(bp); 934 break; 935 } 936 offset += sizeof(struct direntry); 937 while (1) { 938 /* 939 * We are a bit agressive here in that we delete any Win95 940 * entries preceding this entry, not just the ones we "own". 941 * Since these presumably aren't valid anyway, 942 * there should be no harm. 943 */ 944 offset -= sizeof(struct direntry); 945 ep--->deName[0] = SLOT_DELETED; 946 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 947 || !(offset & pmp->pm_crbomask) 948 || ep->deAttributes != ATTR_WIN95) 949 break; 950 } 951 if ((error = bwrite(bp)) != 0) 952 return error; 953 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 954 && !(offset & pmp->pm_crbomask) 955 && offset); 956 return 0; 957 } 958 959 /* 960 * Create a unique DOS name in dvp 961 */ 962 int 963 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp) 964 { 965 struct msdosfsmount *pmp = dep->de_pmp; 966 struct direntry *dentp; 967 int gen; 968 int blsize; 969 u_long cn; 970 daddr_t bn; 971 struct buf *bp; 972 int error; 973 974 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 975 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 976 cnp->cn_namelen, 0, 977 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 978 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu) ? 979 0 : EINVAL); 980 981 for (gen = 1;; gen++) { 982 /* 983 * Generate DOS name with generation number 984 */ 985 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 986 cnp->cn_namelen, gen, 987 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 988 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) 989 return gen == 1 ? EINVAL : EEXIST; 990 991 /* 992 * Now look for a dir entry with this exact name 993 */ 994 for (cn = error = 0; !error; cn++) { 995 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 996 if (error == E2BIG) /* EOF reached and not found */ 997 return 0; 998 return error; 999 } 1000 error = bread(pmp->pm_devvp, bn, blsize, &bp); 1001 if (error) { 1002 brelse(bp); 1003 return error; 1004 } 1005 for (dentp = (struct direntry *)bp->b_data; 1006 (char *)dentp < bp->b_data + blsize; 1007 dentp++) { 1008 if (dentp->deName[0] == SLOT_EMPTY) { 1009 /* 1010 * Last used entry and not found 1011 */ 1012 brelse(bp); 1013 return 0; 1014 } 1015 /* 1016 * Ignore volume labels and Win95 entries 1017 */ 1018 if (dentp->deAttributes & ATTR_VOLUME) 1019 continue; 1020 if (!bcmp(dentp->deName, cp, 11)) { 1021 error = EEXIST; 1022 break; 1023 } 1024 } 1025 brelse(bp); 1026 } 1027 } 1028 } 1029 1030 /* 1031 * Find any Win'95 long filename entry in directory dep 1032 */ 1033 int 1034 findwin95(struct denode *dep) 1035 { 1036 struct msdosfsmount *pmp = dep->de_pmp; 1037 struct direntry *dentp; 1038 int blsize, win95; 1039 u_long cn; 1040 daddr_t bn; 1041 struct buf *bp; 1042 1043 win95 = 1; 1044 /* 1045 * Read through the directory looking for Win'95 entries 1046 * Note: Error currently handled just as EOF XXX 1047 */ 1048 for (cn = 0;; cn++) { 1049 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1050 return (win95); 1051 if (bread(pmp->pm_devvp, bn, blsize, &bp)) { 1052 brelse(bp); 1053 return (win95); 1054 } 1055 for (dentp = (struct direntry *)bp->b_data; 1056 (char *)dentp < bp->b_data + blsize; 1057 dentp++) { 1058 if (dentp->deName[0] == SLOT_EMPTY) { 1059 /* 1060 * Last used entry and not found 1061 */ 1062 brelse(bp); 1063 return (win95); 1064 } 1065 if (dentp->deName[0] == SLOT_DELETED) { 1066 /* 1067 * Ignore deleted files 1068 * Note: might be an indication of Win'95 anyway XXX 1069 */ 1070 continue; 1071 } 1072 if (dentp->deAttributes == ATTR_WIN95) { 1073 brelse(bp); 1074 return 1; 1075 } 1076 win95 = 0; 1077 } 1078 brelse(bp); 1079 } 1080 } 1081