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sys/msdosfs/msdosfs_lookup.c
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1 /* $FreeBSD$ */ 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/buf.h> 55 #include <sys/vnode.h> 56 #include <sys/mount.h> 57 58 #include <msdosfs/bpb.h> 59 #include <msdosfs/direntry.h> 60 #include <msdosfs/denode.h> 61 #include <msdosfs/msdosfsmount.h> 62 #include <msdosfs/fat.h> 63 64 /* 65 * When we search a directory the blocks containing directory entries are 66 * read and examined. The directory entries contain information that would 67 * normally be in the inode of a unix filesystem. This means that some of 68 * a directory's contents may also be in memory resident denodes (sort of 69 * an inode). This can cause problems if we are searching while some other 70 * process is modifying a directory. To prevent one process from accessing 71 * incompletely modified directory information we depend upon being the 72 * sole owner of a directory block. bread/brelse provide this service. 73 * This being the case, when a process modifies a directory it must first 74 * acquire the disk block that contains the directory entry to be modified. 75 * Then update the disk block and the denode, and then write the disk block 76 * out to disk. This way disk blocks containing directory entries and in 77 * memory denode's will be in synch. 78 */ 79 int 80 msdosfs_lookup(ap) 81 struct vop_cachedlookup_args /* { 82 struct vnode *a_dvp; 83 struct vnode **a_vpp; 84 struct componentname *a_cnp; 85 } */ *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 proc *p = cnp->cn_proc; 113 int unlen; 114 115 int wincnt = 1; 116 int chksum = -1; 117 int olddos = 1; 118 cnp->cn_flags &= ~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 & 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++) */ 307 308 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 == 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 cnp->cn_flags |= PDIRUNLOCK; 369 } 370 return (EJUSTRETURN); 371 } 372 /* 373 * Insert name into cache (as non-existent) if appropriate. 374 */ 375 if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE) 376 cache_enter(vdp, *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 == DELETE && (flags & 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_proc); 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, 0, p); 459 cnp->cn_flags |= 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 == RENAME && wantparent && 471 (flags & ISLASTCN)) { 472 if (blkoff == MSDOSFSROOT_OFS) 473 return EROFS; /* really? XXX */ 474 475 error = VOP_ACCESS(vdp, VWRITE, cnp->cn_cred, cnp->cn_proc); 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 |= SAVENAME; 490 if (!lockparent) { 491 VOP_UNLOCK(vdp, 0, p); 492 cnp->cn_flags |= 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 & ISDOTDOT) { 518 VOP_UNLOCK(pdp, 0, p); 519 cnp->cn_flags |= PDIRUNLOCK; 520 error = deget(pmp, cluster, blkoff, &tdp); 521 if (error) { 522 vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, p); 523 cnp->cn_flags &= ~PDIRUNLOCK; 524 return (error); 525 } 526 if (lockparent && (flags & ISLASTCN)) { 527 error = vn_lock(pdp, LK_EXCLUSIVE, p); 528 if (error) { 529 vput(DETOV(tdp)); 530 return (error); 531 } 532 cnp->cn_flags &= ~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 & ISLASTCN)) { 542 VOP_UNLOCK(pdp, 0, p); 543 cnp->cn_flags |= PDIRUNLOCK; 544 } 545 *vpp = DETOV(tdp); 546 } 547 548 /* 549 * Insert name into cache if appropriate. 550 */ 551 if (cnp->cn_flags & MAKEENTRY) 552 cache_enter(vdp, *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(dep, ddep, depp, cnp) 565 struct denode *dep; 566 struct denode *ddep; 567 struct denode **depp; 568 struct componentname *cnp; 569 { 570 int error; 571 u_long dirclust, diroffset; 572 struct direntry *ndep; 573 struct msdosfsmount *pmp = ddep->de_pmp; 574 struct buf *bp; 575 daddr_t bn; 576 int blsize; 577 578 #ifdef MSDOSFS_DEBUG 579 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n", 580 dep, ddep, depp, cnp); 581 #endif 582 583 /* 584 * If no space left in the directory then allocate another cluster 585 * and chain it onto the end of the file. There is one exception 586 * to this. That is, if the root directory has no more space it 587 * can NOT be expanded. extendfile() checks for and fails attempts 588 * to extend the root directory. We just return an error in that 589 * case. 590 */ 591 if (ddep->de_fndoffset >= ddep->de_FileSize) { 592 diroffset = ddep->de_fndoffset + sizeof(struct direntry) 593 - ddep->de_FileSize; 594 dirclust = de_clcount(pmp, diroffset); 595 error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR); 596 if (error) { 597 (void)detrunc(ddep, ddep->de_FileSize, 0, NOCRED, NULL); 598 return error; 599 } 600 601 /* 602 * Update the size of the directory 603 */ 604 ddep->de_FileSize += de_cn2off(pmp, dirclust); 605 } 606 607 /* 608 * We just read in the cluster with space. Copy the new directory 609 * entry in. Then write it to disk. NOTE: DOS directories 610 * do not get smaller as clusters are emptied. 611 */ 612 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset), 613 &bn, &dirclust, &blsize); 614 if (error) 615 return error; 616 diroffset = ddep->de_fndoffset; 617 if (dirclust != MSDOSFSROOT) 618 diroffset &= pmp->pm_crbomask; 619 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) != 0) { 620 brelse(bp); 621 return error; 622 } 623 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 624 625 DE_EXTERNALIZE(ndep, dep); 626 627 /* 628 * Now write the Win95 long name 629 */ 630 if (ddep->de_fndcnt > 0) { 631 u_int8_t chksum = winChksum(ndep->deName); 632 const u_char *un = (const u_char *)cnp->cn_nameptr; 633 int unlen = cnp->cn_namelen; 634 int cnt = 1; 635 636 while (--ddep->de_fndcnt >= 0) { 637 if (!(ddep->de_fndoffset & pmp->pm_crbomask)) { 638 if ((error = bwrite(bp)) != 0) 639 return error; 640 641 ddep->de_fndoffset -= sizeof(struct direntry); 642 error = pcbmap(ddep, 643 de_cluster(pmp, 644 ddep->de_fndoffset), 645 &bn, 0, &blsize); 646 if (error) 647 return error; 648 649 error = bread(pmp->pm_devvp, bn, blsize, 650 NOCRED, &bp); 651 if (error) { 652 brelse(bp); 653 return error; 654 } 655 ndep = bptoep(pmp, bp, ddep->de_fndoffset); 656 } else { 657 ndep--; 658 ddep->de_fndoffset -= sizeof(struct direntry); 659 } 660 if (!unix2winfn(un, unlen, (struct winentry *)ndep, 661 cnt++, chksum, 662 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, 663 pmp->pm_u2w)) 664 break; 665 } 666 } 667 668 if ((error = bwrite(bp)) != 0) 669 return error; 670 671 /* 672 * If they want us to return with the denode gotten. 673 */ 674 if (depp) { 675 if (dep->de_Attributes & ATTR_DIRECTORY) { 676 dirclust = dep->de_StartCluster; 677 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk) 678 dirclust = MSDOSFSROOT; 679 if (dirclust == MSDOSFSROOT) 680 diroffset = MSDOSFSROOT_OFS; 681 else 682 diroffset = 0; 683 } 684 return deget(pmp, dirclust, diroffset, depp); 685 } 686 687 return 0; 688 } 689 690 /* 691 * Be sure a directory is empty except for "." and "..". Return 1 if empty, 692 * return 0 if not empty or error. 693 */ 694 int 695 dosdirempty(dep) 696 struct denode *dep; 697 { 698 int blsize; 699 int error; 700 u_long cn; 701 daddr_t bn; 702 struct buf *bp; 703 struct msdosfsmount *pmp = dep->de_pmp; 704 struct direntry *dentp; 705 706 /* 707 * Since the filesize field in directory entries for a directory is 708 * zero, we just have to feel our way through the directory until 709 * we hit end of file. 710 */ 711 for (cn = 0;; cn++) { 712 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 713 if (error == E2BIG) 714 return (1); /* it's empty */ 715 return (0); 716 } 717 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 718 if (error) { 719 brelse(bp); 720 return (0); 721 } 722 for (dentp = (struct direntry *)bp->b_data; 723 (char *)dentp < bp->b_data + blsize; 724 dentp++) { 725 if (dentp->deName[0] != SLOT_DELETED && 726 (dentp->deAttributes & ATTR_VOLUME) == 0) { 727 /* 728 * In dos directories an entry whose name 729 * starts with SLOT_EMPTY (0) starts the 730 * beginning of the unused part of the 731 * directory, so we can just return that it 732 * is empty. 733 */ 734 if (dentp->deName[0] == SLOT_EMPTY) { 735 brelse(bp); 736 return (1); 737 } 738 /* 739 * Any names other than "." and ".." in a 740 * directory mean it is not empty. 741 */ 742 if (bcmp(dentp->deName, ". ", 11) && 743 bcmp(dentp->deName, ".. ", 11)) { 744 brelse(bp); 745 #ifdef MSDOSFS_DEBUG 746 printf("dosdirempty(): entry found %02x, %02x\n", 747 dentp->deName[0], dentp->deName[1]); 748 #endif 749 return (0); /* not empty */ 750 } 751 } 752 } 753 brelse(bp); 754 } 755 /* NOTREACHED */ 756 } 757 758 /* 759 * Check to see if the directory described by target is in some 760 * subdirectory of source. This prevents something like the following from 761 * succeeding and leaving a bunch or files and directories orphaned. mv 762 * /a/b/c /a/b/c/d/e/f Where c and f are directories. 763 * 764 * source - the inode for /a/b/c 765 * target - the inode for /a/b/c/d/e/f 766 * 767 * Returns 0 if target is NOT a subdirectory of source. 768 * Otherwise returns a non-zero error number. 769 * The target inode is always unlocked on return. 770 */ 771 int 772 doscheckpath(source, target) 773 struct denode *source; 774 struct denode *target; 775 { 776 daddr_t scn; 777 struct msdosfsmount *pmp; 778 struct direntry *ep; 779 struct denode *dep; 780 struct buf *bp = NULL; 781 int error = 0; 782 783 dep = target; 784 if ((target->de_Attributes & ATTR_DIRECTORY) == 0 || 785 (source->de_Attributes & ATTR_DIRECTORY) == 0) { 786 error = ENOTDIR; 787 goto out; 788 } 789 if (dep->de_StartCluster == source->de_StartCluster) { 790 error = EEXIST; 791 goto out; 792 } 793 if (dep->de_StartCluster == MSDOSFSROOT) 794 goto out; 795 pmp = dep->de_pmp; 796 #ifdef DIAGNOSTIC 797 if (pmp != source->de_pmp) 798 panic("doscheckpath: source and target on different filesystems"); 799 #endif 800 if (FAT32(pmp) && dep->de_StartCluster == pmp->pm_rootdirblk) 801 goto out; 802 803 for (;;) { 804 if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) { 805 error = ENOTDIR; 806 break; 807 } 808 scn = dep->de_StartCluster; 809 error = bread(pmp->pm_devvp, cntobn(pmp, scn), 810 pmp->pm_bpcluster, NOCRED, &bp); 811 if (error) 812 break; 813 814 ep = (struct direntry *) bp->b_data + 1; 815 if ((ep->deAttributes & ATTR_DIRECTORY) == 0 || 816 bcmp(ep->deName, ".. ", 11) != 0) { 817 error = ENOTDIR; 818 break; 819 } 820 scn = getushort(ep->deStartCluster); 821 if (FAT32(pmp)) 822 scn |= getushort(ep->deHighClust) << 16; 823 824 if (scn == source->de_StartCluster) { 825 error = EINVAL; 826 break; 827 } 828 if (scn == MSDOSFSROOT) 829 break; 830 if (FAT32(pmp) && scn == pmp->pm_rootdirblk) { 831 /* 832 * scn should be 0 in this case, 833 * but we silently ignore the error. 834 */ 835 break; 836 } 837 838 vput(DETOV(dep)); 839 brelse(bp); 840 bp = NULL; 841 /* NOTE: deget() clears dep on error */ 842 if ((error = deget(pmp, scn, 0, &dep)) != 0) 843 break; 844 } 845 out:; 846 if (bp) 847 brelse(bp); 848 if (error == ENOTDIR) 849 printf("doscheckpath(): .. not a directory?\n"); 850 if (dep != NULL) 851 vput(DETOV(dep)); 852 return (error); 853 } 854 855 /* 856 * Read in the disk block containing the directory entry (dirclu, dirofs) 857 * and return the address of the buf header, and the address of the 858 * directory entry within the block. 859 */ 860 int 861 readep(pmp, dirclust, diroffset, bpp, epp) 862 struct msdosfsmount *pmp; 863 u_long dirclust, diroffset; 864 struct buf **bpp; 865 struct direntry **epp; 866 { 867 int error; 868 daddr_t bn; 869 int blsize; 870 871 blsize = pmp->pm_bpcluster; 872 if (dirclust == MSDOSFSROOT 873 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize) 874 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask; 875 bn = detobn(pmp, dirclust, diroffset); 876 if ((error = bread(pmp->pm_devvp, bn, blsize, NOCRED, bpp)) != 0) { 877 brelse(*bpp); 878 *bpp = NULL; 879 return (error); 880 } 881 if (epp) 882 *epp = bptoep(pmp, *bpp, diroffset); 883 return (0); 884 } 885 886 /* 887 * Read in the disk block containing the directory entry dep came from and 888 * return the address of the buf header, and the address of the directory 889 * entry within the block. 890 */ 891 int 892 readde(dep, bpp, epp) 893 struct denode *dep; 894 struct buf **bpp; 895 struct direntry **epp; 896 { 897 898 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset, 899 bpp, epp)); 900 } 901 902 /* 903 * Remove a directory entry. At this point the file represented by the 904 * directory entry to be removed is still full length until noone has it 905 * open. When the file no longer being used msdosfs_inactive() is called 906 * and will truncate the file to 0 length. When the vnode containing the 907 * denode is needed for some other purpose by VFS it will call 908 * msdosfs_reclaim() which will remove the denode from the denode cache. 909 */ 910 int 911 removede(pdep, dep) 912 struct denode *pdep; /* directory where the entry is removed */ 913 struct denode *dep; /* file to be removed */ 914 { 915 int error; 916 struct direntry *ep; 917 struct buf *bp; 918 daddr_t bn; 919 int blsize; 920 struct msdosfsmount *pmp = pdep->de_pmp; 921 u_long offset = pdep->de_fndoffset; 922 923 #ifdef MSDOSFS_DEBUG 924 printf("removede(): filename %s, dep %p, offset %08lx\n", 925 dep->de_Name, dep, offset); 926 #endif 927 928 dep->de_refcnt--; 929 offset += sizeof(struct direntry); 930 do { 931 offset -= sizeof(struct direntry); 932 error = pcbmap(pdep, de_cluster(pmp, offset), &bn, 0, &blsize); 933 if (error) 934 return error; 935 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 936 if (error) { 937 brelse(bp); 938 return error; 939 } 940 ep = bptoep(pmp, bp, offset); 941 /* 942 * Check whether, if we came here the second time, i.e. 943 * when underflowing into the previous block, the last 944 * entry in this block is a longfilename entry, too. 945 */ 946 if (ep->deAttributes != ATTR_WIN95 947 && offset != pdep->de_fndoffset) { 948 brelse(bp); 949 break; 950 } 951 offset += sizeof(struct direntry); 952 while (1) { 953 /* 954 * We are a bit agressive here in that we delete any Win95 955 * entries preceding this entry, not just the ones we "own". 956 * Since these presumably aren't valid anyway, 957 * there should be no harm. 958 */ 959 offset -= sizeof(struct direntry); 960 ep--->deName[0] = SLOT_DELETED; 961 if ((pmp->pm_flags & MSDOSFSMNT_NOWIN95) 962 || !(offset & pmp->pm_crbomask) 963 || ep->deAttributes != ATTR_WIN95) 964 break; 965 } 966 if ((error = bwrite(bp)) != 0) 967 return error; 968 } while (!(pmp->pm_flags & MSDOSFSMNT_NOWIN95) 969 && !(offset & pmp->pm_crbomask) 970 && offset); 971 return 0; 972 } 973 974 /* 975 * Create a unique DOS name in dvp 976 */ 977 int 978 uniqdosname(dep, cnp, cp) 979 struct denode *dep; 980 struct componentname *cnp; 981 u_char *cp; 982 { 983 struct msdosfsmount *pmp = dep->de_pmp; 984 struct direntry *dentp; 985 int gen; 986 int blsize; 987 u_long cn; 988 daddr_t bn; 989 struct buf *bp; 990 int error; 991 992 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 993 return (unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 994 cnp->cn_namelen, 0, 995 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 996 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu) ? 997 0 : EINVAL); 998 999 for (gen = 1;; gen++) { 1000 /* 1001 * Generate DOS name with generation number 1002 */ 1003 if (!unix2dosfn((const u_char *)cnp->cn_nameptr, cp, 1004 cnp->cn_namelen, gen, 1005 pmp->pm_flags & MSDOSFSMNT_U2WTABLE, pmp->pm_u2d, 1006 pmp->pm_flags & MSDOSFSMNT_ULTABLE, pmp->pm_lu)) 1007 return gen == 1 ? EINVAL : EEXIST; 1008 1009 /* 1010 * Now look for a dir entry with this exact name 1011 */ 1012 for (cn = error = 0; !error; cn++) { 1013 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) { 1014 if (error == E2BIG) /* EOF reached and not found */ 1015 return 0; 1016 return error; 1017 } 1018 error = bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp); 1019 if (error) { 1020 brelse(bp); 1021 return error; 1022 } 1023 for (dentp = (struct direntry *)bp->b_data; 1024 (char *)dentp < bp->b_data + blsize; 1025 dentp++) { 1026 if (dentp->deName[0] == SLOT_EMPTY) { 1027 /* 1028 * Last used entry and not found 1029 */ 1030 brelse(bp); 1031 return 0; 1032 } 1033 /* 1034 * Ignore volume labels and Win95 entries 1035 */ 1036 if (dentp->deAttributes & ATTR_VOLUME) 1037 continue; 1038 if (!bcmp(dentp->deName, cp, 11)) { 1039 error = EEXIST; 1040 break; 1041 } 1042 } 1043 brelse(bp); 1044 } 1045 } 1046 } 1047 1048 /* 1049 * Find any Win'95 long filename entry in directory dep 1050 */ 1051 int 1052 findwin95(dep) 1053 struct denode *dep; 1054 { 1055 struct msdosfsmount *pmp = dep->de_pmp; 1056 struct direntry *dentp; 1057 int blsize, win95; 1058 u_long cn; 1059 daddr_t bn; 1060 struct buf *bp; 1061 1062 win95 = 1; 1063 /* 1064 * Read through the directory looking for Win'95 entries 1065 * Note: Error currently handled just as EOF XXX 1066 */ 1067 for (cn = 0;; cn++) { 1068 if (pcbmap(dep, cn, &bn, 0, &blsize)) 1069 return (win95); 1070 if (bread(pmp->pm_devvp, bn, blsize, NOCRED, &bp)) { 1071 brelse(bp); 1072 return (win95); 1073 } 1074 for (dentp = (struct direntry *)bp->b_data; 1075 (char *)dentp < bp->b_data + blsize; 1076 dentp++) { 1077 if (dentp->deName[0] == SLOT_EMPTY) { 1078 /* 1079 * Last used entry and not found 1080 */ 1081 brelse(bp); 1082 return (win95); 1083 } 1084 if (dentp->deName[0] == SLOT_DELETED) { 1085 /* 1086 * Ignore deleted files 1087 * Note: might be an indication of Win'95 anyway XXX 1088 */ 1089 continue; 1090 } 1091 if (dentp->deAttributes == ATTR_WIN95) { 1092 brelse(bp); 1093 return 1; 1094 } 1095 win95 = 0; 1096 } 1097 brelse(bp); 1098 } 1099 }
Cache object: 0948669cc6c97f6f54b32ee57345e6dd
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