1 /* $NetBSD: msdosfs_vnops.c,v 1.14 2013/01/29 19:45:47 christos Exp $ */ 2 3 /*- 4 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 5 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 6 * All rights reserved. 7 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by TooLs GmbH. 20 * 4. The name of TooLs GmbH may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 28 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 29 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 30 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 31 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 32 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 */ 34 /* 35 * Written by Paul Popelka (paulp@uts.amdahl.com) 36 * 37 * You can do anything you want with this software, just don't say you wrote 38 * it, and don't remove this notice. 39 * 40 * This software is provided "as is". 41 * 42 * The author supplies this software to be publicly redistributed on the 43 * understanding that the author is not responsible for the correct 44 * functioning of this software in any circumstances and is not liable for 45 * any damages caused by this software. 46 * 47 * October 1992 48 */ 49 #if HAVE_NBTOOL_CONFIG_H 50 #include "nbtool_config.h" 51 #endif 52 53 #include <sys/cdefs.h> 54 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vnops.c,v 1.14 2013/01/29 19:45:47 christos Exp $"); 55 56 #include <sys/param.h> 57 #include <sys/mman.h> 58 #include <fcntl.h> 59 #include <unistd.h> 60 61 #include <ffs/buf.h> 62 63 #include <fs/msdosfs/bpb.h> 64 #include <fs/msdosfs/direntry.h> 65 #include <fs/msdosfs/denode.h> 66 #include <fs/msdosfs/msdosfsmount.h> 67 #include <fs/msdosfs/fat.h> 68 69 #include "makefs.h" 70 #include "msdos.h" 71 72 #ifdef MSDOSFS_DEBUG 73 #define DPRINTF(a) printf a 74 #else 75 #define DPRINTF(a) 76 #endif 77 /* 78 * Some general notes: 79 * 80 * In the ufs filesystem the inodes, superblocks, and indirect blocks are 81 * read/written using the vnode for the filesystem. Blocks that represent 82 * the contents of a file are read/written using the vnode for the file 83 * (including directories when they are read/written as files). This 84 * presents problems for the dos filesystem because data that should be in 85 * an inode (if dos had them) resides in the directory itself. Since we 86 * must update directory entries without the benefit of having the vnode 87 * for the directory we must use the vnode for the filesystem. This means 88 * that when a directory is actually read/written (via read, write, or 89 * readdir, or seek) we must use the vnode for the filesystem instead of 90 * the vnode for the directory as would happen in ufs. This is to insure we 91 * retrieve the correct block from the buffer cache since the hash value is 92 * based upon the vnode address and the desired block number. 93 */ 94 95 static int msdosfs_wfile(const char *, struct denode *, fsnode *); 96 97 static void 98 msdosfs_times(struct msdosfsmount *pmp, struct denode *dep, 99 const struct stat *st) 100 { 101 #ifndef HAVE_NBTOOL_CONFIG_H 102 struct timespec at = st->st_atimespec; 103 struct timespec mt = st->st_mtimespec; 104 #else 105 struct timespec at = { st->st_atime, 0 }; 106 struct timespec mt = { st->st_mtime, 0 }; 107 #endif 108 unix2dostime(&at, pmp->pm_gmtoff, &dep->de_ADate, NULL, NULL); 109 unix2dostime(&mt, pmp->pm_gmtoff, &dep->de_MDate, &dep->de_MTime, NULL); 110 } 111 112 /* 113 * When we search a directory the blocks containing directory entries are 114 * read and examined. The directory entries contain information that would 115 * normally be in the inode of a unix filesystem. This means that some of 116 * a directory's contents may also be in memory resident denodes (sort of 117 * an inode). This can cause problems if we are searching while some other 118 * process is modifying a directory. To prevent one process from accessing 119 * incompletely modified directory information we depend upon being the 120 * sole owner of a directory block. bread/brelse provide this service. 121 * This being the case, when a process modifies a directory it must first 122 * acquire the disk block that contains the directory entry to be modified. 123 * Then update the disk block and the denode, and then write the disk block 124 * out to disk. This way disk blocks containing directory entries and in 125 * memory denode's will be in synch. 126 */ 127 static int 128 msdosfs_findslot(struct denode *dp, struct componentname *cnp) 129 { 130 daddr_t bn; 131 int error; 132 int slotcount; 133 int slotoffset = 0; 134 int frcn; 135 u_long cluster; 136 int blkoff; 137 u_int diroff; 138 int blsize; 139 struct denode *tdp; 140 struct msdosfsmount *pmp; 141 struct buf *bp = 0; 142 struct direntry *dep; 143 u_char dosfilename[12]; 144 int wincnt = 1; 145 int chksum = -1, chksum_ok; 146 int olddos = 1; 147 148 pmp = dp->de_pmp; 149 150 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 151 cnp->cn_namelen, 0)) { 152 case 0: 153 return (EINVAL); 154 case 1: 155 break; 156 case 2: 157 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 158 cnp->cn_namelen) + 1; 159 break; 160 case 3: 161 olddos = 0; 162 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 163 cnp->cn_namelen) + 1; 164 break; 165 } 166 167 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 168 wincnt = 1; 169 170 /* 171 * Suppress search for slots unless creating 172 * file and at end of pathname, in which case 173 * we watch for a place to put the new file in 174 * case it doesn't already exist. 175 */ 176 slotcount = 0; 177 DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename)); 178 /* 179 * Search the directory pointed at by vdp for the name pointed at 180 * by cnp->cn_nameptr. 181 */ 182 tdp = NULL; 183 /* 184 * The outer loop ranges over the clusters that make up the 185 * directory. Note that the root directory is different from all 186 * other directories. It has a fixed number of blocks that are not 187 * part of the pool of allocatable clusters. So, we treat it a 188 * little differently. The root directory starts at "cluster" 0. 189 */ 190 diroff = 0; 191 for (frcn = 0; diroff < dp->de_FileSize; frcn++) { 192 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) { 193 if (error == E2BIG) 194 break; 195 return (error); 196 } 197 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED, 198 0, &bp); 199 if (error) { 200 return (error); 201 } 202 for (blkoff = 0; blkoff < blsize; 203 blkoff += sizeof(struct direntry), 204 diroff += sizeof(struct direntry)) { 205 dep = (struct direntry *)((char *)bp->b_data + blkoff); 206 /* 207 * If the slot is empty and we are still looking 208 * for an empty then remember this one. If the 209 * slot is not empty then check to see if it 210 * matches what we are looking for. If the slot 211 * has never been filled with anything, then the 212 * remainder of the directory has never been used, 213 * so there is no point in searching it. 214 */ 215 if (dep->deName[0] == SLOT_EMPTY || 216 dep->deName[0] == SLOT_DELETED) { 217 /* 218 * Drop memory of previous long matches 219 */ 220 chksum = -1; 221 222 if (slotcount < wincnt) { 223 slotcount++; 224 slotoffset = diroff; 225 } 226 if (dep->deName[0] == SLOT_EMPTY) { 227 brelse(bp, 0); 228 goto notfound; 229 } 230 } else { 231 /* 232 * If there wasn't enough space for our 233 * winentries, forget about the empty space 234 */ 235 if (slotcount < wincnt) 236 slotcount = 0; 237 238 /* 239 * Check for Win95 long filename entry 240 */ 241 if (dep->deAttributes == ATTR_WIN95) { 242 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 243 continue; 244 245 chksum = winChkName((const u_char *)cnp->cn_nameptr, 246 cnp->cn_namelen, 247 (struct winentry *)dep, 248 chksum); 249 continue; 250 } 251 252 /* 253 * Ignore volume labels (anywhere, not just 254 * the root directory). 255 */ 256 if (dep->deAttributes & ATTR_VOLUME) { 257 chksum = -1; 258 continue; 259 } 260 261 /* 262 * Check for a checksum or name match 263 */ 264 chksum_ok = (chksum == winChksum(dep->deName)); 265 if (!chksum_ok 266 && (!olddos || memcmp(dosfilename, dep->deName, 11))) { 267 chksum = -1; 268 continue; 269 } 270 DPRINTF(("%s(): match blkoff %d, diroff %d\n", 271 __func__, blkoff, diroff)); 272 /* 273 * Remember where this directory 274 * entry came from for whoever did 275 * this lookup. 276 */ 277 dp->de_fndoffset = diroff; 278 dp->de_fndcnt = 0; 279 280 return EEXIST; 281 } 282 } /* for (blkoff = 0; .... */ 283 /* 284 * Release the buffer holding the directory cluster just 285 * searched. 286 */ 287 brelse(bp, 0); 288 } /* for (frcn = 0; ; frcn++) */ 289 290 notfound: 291 /* 292 * We hold no disk buffers at this point. 293 */ 294 295 /* 296 * If we get here we didn't find the entry we were looking for. But 297 * that's ok if we are creating or renaming and are at the end of 298 * the pathname and the directory hasn't been removed. 299 */ 300 DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n", 301 __func__, dp->de_refcnt, slotcount, slotoffset)); 302 /* 303 * Fixup the slot description to point to the place where 304 * we might put the new DOS direntry (putting the Win95 305 * long name entries before that) 306 */ 307 if (!slotcount) { 308 slotcount = 1; 309 slotoffset = diroff; 310 } 311 if (wincnt > slotcount) { 312 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 313 } 314 315 /* 316 * Return an indication of where the new directory 317 * entry should be put. 318 */ 319 dp->de_fndoffset = slotoffset; 320 dp->de_fndcnt = wincnt - 1; 321 322 /* 323 * We return with the directory locked, so that 324 * the parameters we set up above will still be 325 * valid if we actually decide to do a direnter(). 326 * We return ni_vp == NULL to indicate that the entry 327 * does not currently exist; we leave a pointer to 328 * the (locked) directory inode in ndp->ni_dvp. 329 * 330 * NB - if the directory is unlocked, then this 331 * information cannot be used. 332 */ 333 return 0; 334 } 335 336 /* 337 * Create a regular file. On entry the directory to contain the file being 338 * created is locked. We must release before we return. 339 */ 340 struct denode * 341 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node) 342 { 343 struct componentname cn; 344 struct denode ndirent; 345 struct denode *dep; 346 int error; 347 struct stat *st = &node->inode->st; 348 struct msdosfsmount *pmp = pdep->de_pmp; 349 350 cn.cn_nameptr = node->name; 351 cn.cn_namelen = strlen(node->name); 352 353 DPRINTF(("%s(name %s, mode 0%o size %zu)\n", __func__, node->name, 354 st->st_mode, (size_t)st->st_size)); 355 356 /* 357 * If this is the root directory and there is no space left we 358 * can't do anything. This is because the root directory can not 359 * change size. 360 */ 361 if (pdep->de_StartCluster == MSDOSFSROOT 362 && pdep->de_fndoffset >= pdep->de_FileSize) { 363 error = ENOSPC; 364 goto bad; 365 } 366 367 /* 368 * Create a directory entry for the file, then call createde() to 369 * have it installed. NOTE: DOS files are always executable. We 370 * use the absence of the owner write bit to make the file 371 * readonly. 372 */ 373 memset(&ndirent, 0, sizeof(ndirent)); 374 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 375 goto bad; 376 377 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ? 378 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY; 379 ndirent.de_StartCluster = 0; 380 ndirent.de_FileSize = 0; 381 ndirent.de_dev = pdep->de_dev; 382 ndirent.de_devvp = pdep->de_devvp; 383 ndirent.de_pmp = pdep->de_pmp; 384 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 385 msdosfs_times(pmp, &ndirent, st); 386 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 387 goto bad; 388 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 389 goto bad; 390 if ((error = msdosfs_wfile(path, dep, node)) != 0) 391 goto bad; 392 return dep; 393 394 bad: 395 errno = error; 396 return NULL; 397 } 398 static int 399 msdosfs_updatede(struct denode *dep) 400 { 401 struct buf *bp; 402 struct direntry *dirp; 403 int error; 404 405 dep->de_flag &= ~DE_MODIFIED; 406 error = readde(dep, &bp, &dirp); 407 if (error) 408 return error; 409 DE_EXTERNALIZE(dirp, dep); 410 error = bwrite(bp); 411 return error; 412 } 413 414 /* 415 * Write data to a file or directory. 416 */ 417 static int 418 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node) 419 { 420 int error, fd; 421 size_t osize = dep->de_FileSize; 422 struct stat *st = &node->inode->st; 423 size_t nsize, offs; 424 struct msdosfsmount *pmp = dep->de_pmp; 425 struct buf *bp; 426 char *dat; 427 u_long cn = 0; 428 429 error = 0; /* XXX: gcc/vax */ 430 DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", __func__, 431 dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster)); 432 if (st->st_size == 0) 433 return 0; 434 435 /* Don't bother to try to write files larger than the fs limit */ 436 if (st->st_size > MSDOSFS_FILESIZE_MAX) { 437 errno = EFBIG; 438 return -1; 439 } 440 441 nsize = st->st_size; 442 DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize)); 443 if (nsize > osize) { 444 if ((error = deextend(dep, nsize, NULL)) != 0) { 445 errno = error; 446 return -1; 447 } 448 if ((error = msdosfs_updatede(dep)) != 0) { 449 errno = error; 450 return -1; 451 } 452 } 453 454 if ((fd = open(path, O_RDONLY)) == -1) 455 err(1, "open %s", path); 456 457 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)) 458 == MAP_FAILED) { 459 DPRINTF(("%s: mmap %s %s", __func__, node->name, 460 strerror(errno))); 461 close(fd); 462 goto out; 463 } 464 close(fd); 465 466 for (offs = 0; offs < nsize;) { 467 int blsize, cpsize; 468 daddr_t bn; 469 u_long on = offs & pmp->pm_crbomask; 470 #ifdef HACK 471 cn = dep->de_StartCluster; 472 if (cn == MSDOSFSROOT) { 473 DPRINTF(("%s: bad lbn %lu", __func__, cn)); 474 goto out; 475 } 476 bn = cntobn(pmp, cn); 477 blsize = pmp->pm_bpcluster; 478 #else 479 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) { 480 DPRINTF(("%s: pcbmap %lu", __func__, bn)); 481 goto out; 482 } 483 #endif 484 DPRINTF(("%s(cn=%lu, bn=%llu/%llu, blsize=%d)\n", __func__, 485 cn, (unsigned long long)bn, 486 (unsigned long long)de_bn2kb(pmp, bn), blsize)); 487 if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 488 NULL, 0, &bp)) != 0) { 489 DPRINTF(("bread %d\n", error)); 490 goto out; 491 } 492 cpsize = MIN((nsize - offs), blsize - on); 493 memcpy((char *)bp->b_data + on, dat + offs, cpsize); 494 bwrite(bp); 495 offs += cpsize; 496 } 497 498 munmap(dat, nsize); 499 return 0; 500 out: 501 munmap(dat, nsize); 502 return error; 503 } 504 505 506 static const struct { 507 struct direntry dot; 508 struct direntry dotdot; 509 } dosdirtemplate = { 510 { ". ", " ", /* the . entry */ 511 ATTR_DIRECTORY, /* file attribute */ 512 0, /* reserved */ 513 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 514 { 0, 0 }, /* access date */ 515 { 0, 0 }, /* high bits of start cluster */ 516 { 210, 4 }, { 210, 4 }, /* modify time & date */ 517 { 0, 0 }, /* startcluster */ 518 { 0, 0, 0, 0 } /* filesize */ 519 }, 520 { ".. ", " ", /* the .. entry */ 521 ATTR_DIRECTORY, /* file attribute */ 522 0, /* reserved */ 523 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 524 { 0, 0 }, /* access date */ 525 { 0, 0 }, /* high bits of start cluster */ 526 { 210, 4 }, { 210, 4 }, /* modify time & date */ 527 { 0, 0 }, /* startcluster */ 528 { 0, 0, 0, 0 } /* filesize */ 529 } 530 }; 531 532 struct denode * 533 msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) { 534 struct denode ndirent; 535 struct denode *dep; 536 struct componentname cn; 537 struct stat *st = &node->inode->st; 538 struct msdosfsmount *pmp = pdep->de_pmp; 539 int error; 540 u_long newcluster, pcl, bn; 541 daddr_t lbn; 542 struct direntry *denp; 543 struct buf *bp; 544 545 cn.cn_nameptr = node->name; 546 cn.cn_namelen = strlen(node->name); 547 /* 548 * If this is the root directory and there is no space left we 549 * can't do anything. This is because the root directory can not 550 * change size. 551 */ 552 if (pdep->de_StartCluster == MSDOSFSROOT 553 && pdep->de_fndoffset >= pdep->de_FileSize) { 554 error = ENOSPC; 555 goto bad2; 556 } 557 558 /* 559 * Allocate a cluster to hold the about to be created directory. 560 */ 561 error = clusteralloc(pmp, 0, 1, &newcluster, NULL); 562 if (error) 563 goto bad2; 564 565 memset(&ndirent, 0, sizeof(ndirent)); 566 ndirent.de_pmp = pmp; 567 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 568 msdosfs_times(pmp, &ndirent, st); 569 570 /* 571 * Now fill the cluster with the "." and ".." entries. And write 572 * the cluster to disk. This way it is there for the parent 573 * directory to be pointing at if there were a crash. 574 */ 575 bn = cntobn(pmp, newcluster); 576 lbn = de_bn2kb(pmp, bn); 577 DPRINTF(("%s(newcluster %lu, bn=%lu, lbn=%lu)\n", __func__, newcluster, 578 bn, lbn)); 579 /* always succeeds */ 580 bp = getblk(pmp->pm_devvp, lbn, pmp->pm_bpcluster, 0, 0); 581 memset(bp->b_data, 0, pmp->pm_bpcluster); 582 memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate); 583 denp = (struct direntry *)bp->b_data; 584 putushort(denp[0].deStartCluster, newcluster); 585 putushort(denp[0].deCDate, ndirent.de_CDate); 586 putushort(denp[0].deCTime, ndirent.de_CTime); 587 denp[0].deCHundredth = ndirent.de_CHun; 588 putushort(denp[0].deADate, ndirent.de_ADate); 589 putushort(denp[0].deMDate, ndirent.de_MDate); 590 putushort(denp[0].deMTime, ndirent.de_MTime); 591 pcl = pdep->de_StartCluster; 592 DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl, 593 pmp->pm_rootdirblk)); 594 if (FAT32(pmp) && pcl == pmp->pm_rootdirblk) 595 pcl = 0; 596 putushort(denp[1].deStartCluster, pcl); 597 putushort(denp[1].deCDate, ndirent.de_CDate); 598 putushort(denp[1].deCTime, ndirent.de_CTime); 599 denp[1].deCHundredth = ndirent.de_CHun; 600 putushort(denp[1].deADate, ndirent.de_ADate); 601 putushort(denp[1].deMDate, ndirent.de_MDate); 602 putushort(denp[1].deMTime, ndirent.de_MTime); 603 if (FAT32(pmp)) { 604 putushort(denp[0].deHighClust, newcluster >> 16); 605 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16); 606 } else { 607 putushort(denp[0].deHighClust, 0); 608 putushort(denp[1].deHighClust, 0); 609 } 610 611 if ((error = bwrite(bp)) != 0) 612 goto bad; 613 614 /* 615 * Now build up a directory entry pointing to the newly allocated 616 * cluster. This will be written to an empty slot in the parent 617 * directory. 618 */ 619 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 620 goto bad; 621 622 ndirent.de_Attributes = ATTR_DIRECTORY; 623 ndirent.de_StartCluster = newcluster; 624 ndirent.de_FileSize = 0; 625 ndirent.de_dev = pdep->de_dev; 626 ndirent.de_devvp = pdep->de_devvp; 627 ndirent.de_pmp = pdep->de_pmp; 628 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 629 goto bad; 630 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 631 goto bad; 632 if ((error = msdosfs_updatede(dep)) != 0) 633 goto bad; 634 return dep; 635 636 bad: 637 clusterfree(pmp, newcluster, NULL); 638 bad2: 639 errno = error; 640 return NULL; 641 } 642