1 /* $NetBSD: msdosfs_vnops.c,v 1.15 2013/10/19 17:16:37 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 1.15 2013/10/19 17:16:37 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 msdosfsmount *pmp; 140 struct buf *bp = 0; 141 struct direntry *dep; 142 u_char dosfilename[12]; 143 int wincnt = 1; 144 int chksum = -1, chksum_ok; 145 int olddos = 1; 146 147 pmp = dp->de_pmp; 148 149 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 150 cnp->cn_namelen, 0)) { 151 case 0: 152 return (EINVAL); 153 case 1: 154 break; 155 case 2: 156 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 157 cnp->cn_namelen) + 1; 158 break; 159 case 3: 160 olddos = 0; 161 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 162 cnp->cn_namelen) + 1; 163 break; 164 } 165 166 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 167 wincnt = 1; 168 169 /* 170 * Suppress search for slots unless creating 171 * file and at end of pathname, in which case 172 * we watch for a place to put the new file in 173 * case it doesn't already exist. 174 */ 175 slotcount = 0; 176 DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename)); 177 /* 178 * Search the directory pointed at by vdp for the name pointed at 179 * by cnp->cn_nameptr. 180 */ 181 /* 182 * The outer loop ranges over the clusters that make up the 183 * directory. Note that the root directory is different from all 184 * other directories. It has a fixed number of blocks that are not 185 * part of the pool of allocatable clusters. So, we treat it a 186 * little differently. The root directory starts at "cluster" 0. 187 */ 188 diroff = 0; 189 for (frcn = 0; diroff < dp->de_FileSize; frcn++) { 190 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) { 191 if (error == E2BIG) 192 break; 193 return (error); 194 } 195 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED, 196 0, &bp); 197 if (error) { 198 return (error); 199 } 200 for (blkoff = 0; blkoff < blsize; 201 blkoff += sizeof(struct direntry), 202 diroff += sizeof(struct direntry)) { 203 dep = (struct direntry *)((char *)bp->b_data + blkoff); 204 /* 205 * If the slot is empty and we are still looking 206 * for an empty then remember this one. If the 207 * slot is not empty then check to see if it 208 * matches what we are looking for. If the slot 209 * has never been filled with anything, then the 210 * remainder of the directory has never been used, 211 * so there is no point in searching it. 212 */ 213 if (dep->deName[0] == SLOT_EMPTY || 214 dep->deName[0] == SLOT_DELETED) { 215 /* 216 * Drop memory of previous long matches 217 */ 218 chksum = -1; 219 220 if (slotcount < wincnt) { 221 slotcount++; 222 slotoffset = diroff; 223 } 224 if (dep->deName[0] == SLOT_EMPTY) { 225 brelse(bp, 0); 226 goto notfound; 227 } 228 } else { 229 /* 230 * If there wasn't enough space for our 231 * winentries, forget about the empty space 232 */ 233 if (slotcount < wincnt) 234 slotcount = 0; 235 236 /* 237 * Check for Win95 long filename entry 238 */ 239 if (dep->deAttributes == ATTR_WIN95) { 240 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 241 continue; 242 243 chksum = winChkName((const u_char *)cnp->cn_nameptr, 244 cnp->cn_namelen, 245 (struct winentry *)dep, 246 chksum); 247 continue; 248 } 249 250 /* 251 * Ignore volume labels (anywhere, not just 252 * the root directory). 253 */ 254 if (dep->deAttributes & ATTR_VOLUME) { 255 chksum = -1; 256 continue; 257 } 258 259 /* 260 * Check for a checksum or name match 261 */ 262 chksum_ok = (chksum == winChksum(dep->deName)); 263 if (!chksum_ok 264 && (!olddos || memcmp(dosfilename, dep->deName, 11))) { 265 chksum = -1; 266 continue; 267 } 268 DPRINTF(("%s(): match blkoff %d, diroff %d\n", 269 __func__, blkoff, diroff)); 270 /* 271 * Remember where this directory 272 * entry came from for whoever did 273 * this lookup. 274 */ 275 dp->de_fndoffset = diroff; 276 dp->de_fndcnt = 0; 277 278 return EEXIST; 279 } 280 } /* for (blkoff = 0; .... */ 281 /* 282 * Release the buffer holding the directory cluster just 283 * searched. 284 */ 285 brelse(bp, 0); 286 } /* for (frcn = 0; ; frcn++) */ 287 288 notfound: 289 /* 290 * We hold no disk buffers at this point. 291 */ 292 293 /* 294 * If we get here we didn't find the entry we were looking for. But 295 * that's ok if we are creating or renaming and are at the end of 296 * the pathname and the directory hasn't been removed. 297 */ 298 DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n", 299 __func__, dp->de_refcnt, slotcount, slotoffset)); 300 /* 301 * Fixup the slot description to point to the place where 302 * we might put the new DOS direntry (putting the Win95 303 * long name entries before that) 304 */ 305 if (!slotcount) { 306 slotcount = 1; 307 slotoffset = diroff; 308 } 309 if (wincnt > slotcount) { 310 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 311 } 312 313 /* 314 * Return an indication of where the new directory 315 * entry should be put. 316 */ 317 dp->de_fndoffset = slotoffset; 318 dp->de_fndcnt = wincnt - 1; 319 320 /* 321 * We return with the directory locked, so that 322 * the parameters we set up above will still be 323 * valid if we actually decide to do a direnter(). 324 * We return ni_vp == NULL to indicate that the entry 325 * does not currently exist; we leave a pointer to 326 * the (locked) directory inode in ndp->ni_dvp. 327 * 328 * NB - if the directory is unlocked, then this 329 * information cannot be used. 330 */ 331 return 0; 332 } 333 334 /* 335 * Create a regular file. On entry the directory to contain the file being 336 * created is locked. We must release before we return. 337 */ 338 struct denode * 339 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node) 340 { 341 struct componentname cn; 342 struct denode ndirent; 343 struct denode *dep; 344 int error; 345 struct stat *st = &node->inode->st; 346 struct msdosfsmount *pmp = pdep->de_pmp; 347 348 cn.cn_nameptr = node->name; 349 cn.cn_namelen = strlen(node->name); 350 351 DPRINTF(("%s(name %s, mode 0%o size %zu)\n", __func__, node->name, 352 st->st_mode, (size_t)st->st_size)); 353 354 /* 355 * If this is the root directory and there is no space left we 356 * can't do anything. This is because the root directory can not 357 * change size. 358 */ 359 if (pdep->de_StartCluster == MSDOSFSROOT 360 && pdep->de_fndoffset >= pdep->de_FileSize) { 361 error = ENOSPC; 362 goto bad; 363 } 364 365 /* 366 * Create a directory entry for the file, then call createde() to 367 * have it installed. NOTE: DOS files are always executable. We 368 * use the absence of the owner write bit to make the file 369 * readonly. 370 */ 371 memset(&ndirent, 0, sizeof(ndirent)); 372 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 373 goto bad; 374 375 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ? 376 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY; 377 ndirent.de_StartCluster = 0; 378 ndirent.de_FileSize = 0; 379 ndirent.de_dev = pdep->de_dev; 380 ndirent.de_devvp = pdep->de_devvp; 381 ndirent.de_pmp = pdep->de_pmp; 382 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 383 msdosfs_times(pmp, &ndirent, st); 384 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 385 goto bad; 386 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 387 goto bad; 388 if ((error = msdosfs_wfile(path, dep, node)) != 0) 389 goto bad; 390 return dep; 391 392 bad: 393 errno = error; 394 return NULL; 395 } 396 static int 397 msdosfs_updatede(struct denode *dep) 398 { 399 struct buf *bp; 400 struct direntry *dirp; 401 int error; 402 403 dep->de_flag &= ~DE_MODIFIED; 404 error = readde(dep, &bp, &dirp); 405 if (error) 406 return error; 407 DE_EXTERNALIZE(dirp, dep); 408 error = bwrite(bp); 409 return error; 410 } 411 412 /* 413 * Write data to a file or directory. 414 */ 415 static int 416 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node) 417 { 418 int error, fd; 419 size_t osize = dep->de_FileSize; 420 struct stat *st = &node->inode->st; 421 size_t nsize, offs; 422 struct msdosfsmount *pmp = dep->de_pmp; 423 struct buf *bp; 424 char *dat; 425 u_long cn = 0; 426 427 error = 0; /* XXX: gcc/vax */ 428 DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", __func__, 429 dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster)); 430 if (st->st_size == 0) 431 return 0; 432 433 /* Don't bother to try to write files larger than the fs limit */ 434 if (st->st_size > MSDOSFS_FILESIZE_MAX) { 435 errno = EFBIG; 436 return -1; 437 } 438 439 nsize = st->st_size; 440 DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize)); 441 if (nsize > osize) { 442 if ((error = deextend(dep, nsize, NULL)) != 0) { 443 errno = error; 444 return -1; 445 } 446 if ((error = msdosfs_updatede(dep)) != 0) { 447 errno = error; 448 return -1; 449 } 450 } 451 452 if ((fd = open(path, O_RDONLY)) == -1) 453 err(1, "open %s", path); 454 455 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)) 456 == MAP_FAILED) { 457 DPRINTF(("%s: mmap %s %s", __func__, node->name, 458 strerror(errno))); 459 close(fd); 460 goto out; 461 } 462 close(fd); 463 464 for (offs = 0; offs < nsize;) { 465 int blsize, cpsize; 466 daddr_t bn; 467 u_long on = offs & pmp->pm_crbomask; 468 #ifdef HACK 469 cn = dep->de_StartCluster; 470 if (cn == MSDOSFSROOT) { 471 DPRINTF(("%s: bad lbn %lu", __func__, cn)); 472 goto out; 473 } 474 bn = cntobn(pmp, cn); 475 blsize = pmp->pm_bpcluster; 476 #else 477 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) { 478 DPRINTF(("%s: pcbmap %lu", __func__, bn)); 479 goto out; 480 } 481 #endif 482 DPRINTF(("%s(cn=%lu, bn=%llu/%llu, blsize=%d)\n", __func__, 483 cn, (unsigned long long)bn, 484 (unsigned long long)de_bn2kb(pmp, bn), blsize)); 485 if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 486 NULL, 0, &bp)) != 0) { 487 DPRINTF(("bread %d\n", error)); 488 goto out; 489 } 490 cpsize = MIN((nsize - offs), blsize - on); 491 memcpy((char *)bp->b_data + on, dat + offs, cpsize); 492 bwrite(bp); 493 offs += cpsize; 494 } 495 496 munmap(dat, nsize); 497 return 0; 498 out: 499 munmap(dat, nsize); 500 return error; 501 } 502 503 504 static const struct { 505 struct direntry dot; 506 struct direntry dotdot; 507 } dosdirtemplate = { 508 { ". ", " ", /* the . entry */ 509 ATTR_DIRECTORY, /* file attribute */ 510 0, /* reserved */ 511 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 512 { 0, 0 }, /* access date */ 513 { 0, 0 }, /* high bits of start cluster */ 514 { 210, 4 }, { 210, 4 }, /* modify time & date */ 515 { 0, 0 }, /* startcluster */ 516 { 0, 0, 0, 0 } /* filesize */ 517 }, 518 { ".. ", " ", /* the .. entry */ 519 ATTR_DIRECTORY, /* file attribute */ 520 0, /* reserved */ 521 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 522 { 0, 0 }, /* access date */ 523 { 0, 0 }, /* high bits of start cluster */ 524 { 210, 4 }, { 210, 4 }, /* modify time & date */ 525 { 0, 0 }, /* startcluster */ 526 { 0, 0, 0, 0 } /* filesize */ 527 } 528 }; 529 530 struct denode * 531 msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) { 532 struct denode ndirent; 533 struct denode *dep; 534 struct componentname cn; 535 struct stat *st = &node->inode->st; 536 struct msdosfsmount *pmp = pdep->de_pmp; 537 int error; 538 u_long newcluster, pcl, bn; 539 daddr_t lbn; 540 struct direntry *denp; 541 struct buf *bp; 542 543 cn.cn_nameptr = node->name; 544 cn.cn_namelen = strlen(node->name); 545 /* 546 * If this is the root directory and there is no space left we 547 * can't do anything. This is because the root directory can not 548 * change size. 549 */ 550 if (pdep->de_StartCluster == MSDOSFSROOT 551 && pdep->de_fndoffset >= pdep->de_FileSize) { 552 error = ENOSPC; 553 goto bad2; 554 } 555 556 /* 557 * Allocate a cluster to hold the about to be created directory. 558 */ 559 error = clusteralloc(pmp, 0, 1, &newcluster, NULL); 560 if (error) 561 goto bad2; 562 563 memset(&ndirent, 0, sizeof(ndirent)); 564 ndirent.de_pmp = pmp; 565 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 566 msdosfs_times(pmp, &ndirent, st); 567 568 /* 569 * Now fill the cluster with the "." and ".." entries. And write 570 * the cluster to disk. This way it is there for the parent 571 * directory to be pointing at if there were a crash. 572 */ 573 bn = cntobn(pmp, newcluster); 574 lbn = de_bn2kb(pmp, bn); 575 DPRINTF(("%s(newcluster %lu, bn=%lu, lbn=%lu)\n", __func__, newcluster, 576 bn, lbn)); 577 /* always succeeds */ 578 bp = getblk(pmp->pm_devvp, lbn, pmp->pm_bpcluster, 0, 0); 579 memset(bp->b_data, 0, pmp->pm_bpcluster); 580 memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate); 581 denp = (struct direntry *)bp->b_data; 582 putushort(denp[0].deStartCluster, newcluster); 583 putushort(denp[0].deCDate, ndirent.de_CDate); 584 putushort(denp[0].deCTime, ndirent.de_CTime); 585 denp[0].deCHundredth = ndirent.de_CHun; 586 putushort(denp[0].deADate, ndirent.de_ADate); 587 putushort(denp[0].deMDate, ndirent.de_MDate); 588 putushort(denp[0].deMTime, ndirent.de_MTime); 589 pcl = pdep->de_StartCluster; 590 DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl, 591 pmp->pm_rootdirblk)); 592 if (FAT32(pmp) && pcl == pmp->pm_rootdirblk) 593 pcl = 0; 594 putushort(denp[1].deStartCluster, pcl); 595 putushort(denp[1].deCDate, ndirent.de_CDate); 596 putushort(denp[1].deCTime, ndirent.de_CTime); 597 denp[1].deCHundredth = ndirent.de_CHun; 598 putushort(denp[1].deADate, ndirent.de_ADate); 599 putushort(denp[1].deMDate, ndirent.de_MDate); 600 putushort(denp[1].deMTime, ndirent.de_MTime); 601 if (FAT32(pmp)) { 602 putushort(denp[0].deHighClust, newcluster >> 16); 603 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16); 604 } else { 605 putushort(denp[0].deHighClust, 0); 606 putushort(denp[1].deHighClust, 0); 607 } 608 609 if ((error = bwrite(bp)) != 0) 610 goto bad; 611 612 /* 613 * Now build up a directory entry pointing to the newly allocated 614 * cluster. This will be written to an empty slot in the parent 615 * directory. 616 */ 617 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 618 goto bad; 619 620 ndirent.de_Attributes = ATTR_DIRECTORY; 621 ndirent.de_StartCluster = newcluster; 622 ndirent.de_FileSize = 0; 623 ndirent.de_dev = pdep->de_dev; 624 ndirent.de_devvp = pdep->de_devvp; 625 ndirent.de_pmp = pdep->de_pmp; 626 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 627 goto bad; 628 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 629 goto bad; 630 if ((error = msdosfs_updatede(dep)) != 0) 631 goto bad; 632 return dep; 633 634 bad: 635 clusterfree(pmp, newcluster, NULL); 636 bad2: 637 errno = error; 638 return NULL; 639 } 640