1 /* $NetBSD: msdosfs_vnops.c,v 1.19 2017/04/13 17:10:12 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 __FBSDID("$FreeBSD$"); 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 struct timespec at; 102 struct timespec mt; 103 104 if (stampst.st_ino) 105 st = &stampst; 106 107 #ifndef HAVE_NBTOOL_CONFIG_H 108 at = st->st_atimespec; 109 mt = st->st_mtimespec; 110 #else 111 at.tv_sec = st->st_atime; 112 at.tv_nsec = 0; 113 mt.tv_sec = st->st_mtime; 114 mt.tv_nsec = 0; 115 #endif 116 unix2dostime(&at, pmp->pm_gmtoff, &dep->de_ADate, NULL, NULL); 117 unix2dostime(&mt, pmp->pm_gmtoff, &dep->de_MDate, &dep->de_MTime, NULL); 118 } 119 120 /* 121 * When we search a directory the blocks containing directory entries are 122 * read and examined. The directory entries contain information that would 123 * normally be in the inode of a unix filesystem. This means that some of 124 * a directory's contents may also be in memory resident denodes (sort of 125 * an inode). This can cause problems if we are searching while some other 126 * process is modifying a directory. To prevent one process from accessing 127 * incompletely modified directory information we depend upon being the 128 * sole owner of a directory block. bread/brelse provide this service. 129 * This being the case, when a process modifies a directory it must first 130 * acquire the disk block that contains the directory entry to be modified. 131 * Then update the disk block and the denode, and then write the disk block 132 * out to disk. This way disk blocks containing directory entries and in 133 * memory denode's will be in synch. 134 */ 135 static int 136 msdosfs_findslot(struct denode *dp, struct componentname *cnp) 137 { 138 daddr_t bn; 139 int error; 140 int slotcount; 141 int slotoffset = 0; 142 int frcn; 143 u_long cluster; 144 int blkoff; 145 u_int diroff; 146 int blsize; 147 struct msdosfsmount *pmp; 148 struct buf *bp = 0; 149 struct direntry *dep; 150 u_char dosfilename[12]; 151 int wincnt = 1; 152 int chksum = -1, chksum_ok; 153 int olddos = 1; 154 155 pmp = dp->de_pmp; 156 157 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 158 cnp->cn_namelen, 0)) { 159 case 0: 160 return (EINVAL); 161 case 1: 162 break; 163 case 2: 164 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 165 cnp->cn_namelen, pmp->pm_flags & MSDOSFSMNT_UTF8) + 1; 166 break; 167 case 3: 168 olddos = 0; 169 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 170 cnp->cn_namelen, pmp->pm_flags & MSDOSFSMNT_UTF8) + 1; 171 break; 172 } 173 174 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 175 wincnt = 1; 176 177 /* 178 * Suppress search for slots unless creating 179 * file and at end of pathname, in which case 180 * we watch for a place to put the new file in 181 * case it doesn't already exist. 182 */ 183 slotcount = 0; 184 DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename)); 185 /* 186 * Search the directory pointed at by vdp for the name pointed at 187 * by cnp->cn_nameptr. 188 */ 189 /* 190 * The outer loop ranges over the clusters that make up the 191 * directory. Note that the root directory is different from all 192 * other directories. It has a fixed number of blocks that are not 193 * part of the pool of allocatable clusters. So, we treat it a 194 * little differently. The root directory starts at "cluster" 0. 195 */ 196 diroff = 0; 197 for (frcn = 0; diroff < dp->de_FileSize; frcn++) { 198 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) { 199 if (error == E2BIG) 200 break; 201 return (error); 202 } 203 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 204 0, &bp); 205 if (error) { 206 return (error); 207 } 208 for (blkoff = 0; blkoff < blsize; 209 blkoff += sizeof(struct direntry), 210 diroff += sizeof(struct direntry)) { 211 dep = (struct direntry *)((char *)bp->b_data + blkoff); 212 /* 213 * If the slot is empty and we are still looking 214 * for an empty then remember this one. If the 215 * slot is not empty then check to see if it 216 * matches what we are looking for. If the slot 217 * has never been filled with anything, then the 218 * remainder of the directory has never been used, 219 * so there is no point in searching it. 220 */ 221 if (dep->deName[0] == SLOT_EMPTY || 222 dep->deName[0] == SLOT_DELETED) { 223 /* 224 * Drop memory of previous long matches 225 */ 226 chksum = -1; 227 228 if (slotcount < wincnt) { 229 slotcount++; 230 slotoffset = diroff; 231 } 232 if (dep->deName[0] == SLOT_EMPTY) { 233 brelse(bp); 234 goto notfound; 235 } 236 } else { 237 /* 238 * If there wasn't enough space for our 239 * winentries, forget about the empty space 240 */ 241 if (slotcount < wincnt) 242 slotcount = 0; 243 244 /* 245 * Check for Win95 long filename entry 246 */ 247 if (dep->deAttributes == ATTR_WIN95) { 248 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 249 continue; 250 251 chksum = winChkName((const u_char *)cnp->cn_nameptr, 252 cnp->cn_namelen, 253 (struct winentry *)dep, 254 chksum, 255 pmp->pm_flags & MSDOSFSMNT_UTF8); 256 continue; 257 } 258 259 /* 260 * Ignore volume labels (anywhere, not just 261 * the root directory). 262 */ 263 if (dep->deAttributes & ATTR_VOLUME) { 264 chksum = -1; 265 continue; 266 } 267 268 /* 269 * Check for a checksum or name match 270 */ 271 chksum_ok = (chksum == winChksum(dep->deName)); 272 if (!chksum_ok 273 && (!olddos || memcmp(dosfilename, dep->deName, 11))) { 274 chksum = -1; 275 continue; 276 } 277 DPRINTF(("%s(): match blkoff %d, diroff %d\n", 278 __func__, blkoff, diroff)); 279 /* 280 * Remember where this directory 281 * entry came from for whoever did 282 * this lookup. 283 */ 284 dp->de_fndoffset = diroff; 285 dp->de_fndcnt = 0; 286 287 return EEXIST; 288 } 289 } /* for (blkoff = 0; .... */ 290 /* 291 * Release the buffer holding the directory cluster just 292 * searched. 293 */ 294 brelse(bp); 295 } /* for (frcn = 0; ; frcn++) */ 296 297 notfound: 298 /* 299 * We hold no disk buffers at this point. 300 */ 301 302 /* 303 * If we get here we didn't find the entry we were looking for. But 304 * that's ok if we are creating or renaming and are at the end of 305 * the pathname and the directory hasn't been removed. 306 */ 307 DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n", 308 __func__, dp->de_refcnt, slotcount, slotoffset)); 309 /* 310 * Fixup the slot description to point to the place where 311 * we might put the new DOS direntry (putting the Win95 312 * long name entries before that) 313 */ 314 if (!slotcount) { 315 slotcount = 1; 316 slotoffset = diroff; 317 } 318 if (wincnt > slotcount) { 319 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 320 } 321 322 /* 323 * Return an indication of where the new directory 324 * entry should be put. 325 */ 326 dp->de_fndoffset = slotoffset; 327 dp->de_fndcnt = wincnt - 1; 328 329 /* 330 * We return with the directory locked, so that 331 * the parameters we set up above will still be 332 * valid if we actually decide to do a direnter(). 333 * We return ni_vp == NULL to indicate that the entry 334 * does not currently exist; we leave a pointer to 335 * the (locked) directory inode in ndp->ni_dvp. 336 * 337 * NB - if the directory is unlocked, then this 338 * information cannot be used. 339 */ 340 return 0; 341 } 342 343 /* 344 * Create a regular file. On entry the directory to contain the file being 345 * created is locked. We must release before we return. 346 */ 347 struct denode * 348 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node) 349 { 350 struct componentname cn; 351 struct denode ndirent; 352 struct denode *dep; 353 int error; 354 struct stat *st = &node->inode->st; 355 struct msdosfsmount *pmp = pdep->de_pmp; 356 357 cn.cn_nameptr = node->name; 358 cn.cn_namelen = strlen(node->name); 359 360 DPRINTF(("%s(name %s, mode 0%o size %zu)\n", __func__, node->name, 361 st->st_mode, (size_t)st->st_size)); 362 363 /* 364 * If this is the root directory and there is no space left we 365 * can't do anything. This is because the root directory can not 366 * change size. 367 */ 368 if (pdep->de_StartCluster == MSDOSFSROOT 369 && pdep->de_fndoffset >= pdep->de_FileSize) { 370 error = ENOSPC; 371 goto bad; 372 } 373 374 /* 375 * Create a directory entry for the file, then call createde() to 376 * have it installed. NOTE: DOS files are always executable. We 377 * use the absence of the owner write bit to make the file 378 * readonly. 379 */ 380 memset(&ndirent, 0, sizeof(ndirent)); 381 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 382 goto bad; 383 384 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ? 385 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY; 386 ndirent.de_StartCluster = 0; 387 ndirent.de_FileSize = 0; 388 ndirent.de_dev = pdep->de_dev; 389 ndirent.de_devvp = pdep->de_devvp; 390 ndirent.de_pmp = pdep->de_pmp; 391 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 392 msdosfs_times(pmp, &ndirent, st); 393 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 394 goto bad; 395 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 396 goto bad; 397 if ((error = msdosfs_wfile(path, dep, node)) != 0) 398 goto bad; 399 return dep; 400 401 bad: 402 errno = error; 403 return NULL; 404 } 405 static int 406 msdosfs_updatede(struct denode *dep) 407 { 408 struct buf *bp; 409 struct direntry *dirp; 410 int error; 411 412 dep->de_flag &= ~DE_MODIFIED; 413 error = readde(dep, &bp, &dirp); 414 if (error) 415 return error; 416 DE_EXTERNALIZE(dirp, dep); 417 error = bwrite(bp); 418 return error; 419 } 420 421 /* 422 * Write data to a file or directory. 423 */ 424 static int 425 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node) 426 { 427 int error, fd; 428 size_t osize = dep->de_FileSize; 429 struct stat *st = &node->inode->st; 430 size_t nsize, offs; 431 struct msdosfsmount *pmp = dep->de_pmp; 432 struct buf *bp; 433 char *dat; 434 u_long cn = 0; 435 436 error = 0; /* XXX: gcc/vax */ 437 DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", __func__, 438 dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster)); 439 if (st->st_size == 0) 440 return 0; 441 442 /* Don't bother to try to write files larger than the fs limit */ 443 if (st->st_size > MSDOSFS_FILESIZE_MAX) 444 return EFBIG; 445 446 nsize = st->st_size; 447 DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize)); 448 if (nsize > osize) { 449 if ((error = deextend(dep, nsize, NULL)) != 0) 450 return error; 451 if ((error = msdosfs_updatede(dep)) != 0) 452 return error; 453 } 454 455 if ((fd = open(path, O_RDONLY)) == -1) { 456 error = errno; 457 DPRINTF((1, "open %s: %s", path, strerror(error))); 458 return error; 459 } 460 461 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)) 462 == MAP_FAILED) { 463 error = errno; 464 DPRINTF(("%s: mmap %s: %s", __func__, node->name, 465 strerror(error))); 466 close(fd); 467 goto out; 468 } 469 close(fd); 470 471 for (offs = 0; offs < nsize;) { 472 int blsize, cpsize; 473 daddr_t bn; 474 u_long on = offs & pmp->pm_crbomask; 475 #ifdef HACK 476 cn = dep->de_StartCluster; 477 if (cn == MSDOSFSROOT) { 478 DPRINTF(("%s: bad lbn %lu", __func__, cn)); 479 error = EINVAL; 480 goto out; 481 } 482 bn = cntobn(pmp, cn); 483 blsize = pmp->pm_bpcluster; 484 #else 485 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) { 486 DPRINTF(("%s: pcbmap %lu", __func__, bn)); 487 goto out; 488 } 489 #endif 490 DPRINTF(("%s(cn=%lu, bn=%llu/%llu, blsize=%d)\n", __func__, 491 cn, (unsigned long long)bn, 492 (unsigned long long)de_bn2kb(pmp, bn), blsize)); 493 if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, 494 0, &bp)) != 0) { 495 DPRINTF(("bread %d\n", error)); 496 goto out; 497 } 498 cpsize = MIN((nsize - offs), blsize - on); 499 memcpy((char *)bp->b_data + on, dat + offs, cpsize); 500 bwrite(bp); 501 offs += cpsize; 502 } 503 504 munmap(dat, nsize); 505 return 0; 506 out: 507 munmap(dat, nsize); 508 return error; 509 } 510 511 512 static const struct { 513 struct direntry dot; 514 struct direntry dotdot; 515 } dosdirtemplate = { 516 { ". ", " ", /* the . entry */ 517 ATTR_DIRECTORY, /* file attribute */ 518 0, /* reserved */ 519 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 520 { 0, 0 }, /* access date */ 521 { 0, 0 }, /* high bits of start cluster */ 522 { 210, 4 }, { 210, 4 }, /* modify time & date */ 523 { 0, 0 }, /* startcluster */ 524 { 0, 0, 0, 0 } /* filesize */ 525 }, 526 { ".. ", " ", /* the .. entry */ 527 ATTR_DIRECTORY, /* file attribute */ 528 0, /* reserved */ 529 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 530 { 0, 0 }, /* access date */ 531 { 0, 0 }, /* high bits of start cluster */ 532 { 210, 4 }, { 210, 4 }, /* modify time & date */ 533 { 0, 0 }, /* startcluster */ 534 { 0, 0, 0, 0 } /* filesize */ 535 } 536 }; 537 538 struct denode * 539 msdosfs_mkdire(const char *path, struct denode *pdep, fsnode *node) { 540 struct denode ndirent; 541 struct denode *dep; 542 struct componentname cn; 543 struct stat *st = &node->inode->st; 544 struct msdosfsmount *pmp = pdep->de_pmp; 545 int error; 546 u_long newcluster, pcl, bn; 547 daddr_t lbn; 548 struct direntry *denp; 549 struct buf *bp; 550 551 cn.cn_nameptr = node->name; 552 cn.cn_namelen = strlen(node->name); 553 /* 554 * If this is the root directory and there is no space left we 555 * can't do anything. This is because the root directory can not 556 * change size. 557 */ 558 if (pdep->de_StartCluster == MSDOSFSROOT 559 && pdep->de_fndoffset >= pdep->de_FileSize) { 560 error = ENOSPC; 561 goto bad2; 562 } 563 564 /* 565 * Allocate a cluster to hold the about to be created directory. 566 */ 567 error = clusteralloc(pmp, 0, 1, &newcluster, NULL); 568 if (error) 569 goto bad2; 570 571 memset(&ndirent, 0, sizeof(ndirent)); 572 ndirent.de_pmp = pmp; 573 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 574 msdosfs_times(pmp, &ndirent, st); 575 576 /* 577 * Now fill the cluster with the "." and ".." entries. And write 578 * the cluster to disk. This way it is there for the parent 579 * directory to be pointing at if there were a crash. 580 */ 581 bn = cntobn(pmp, newcluster); 582 lbn = de_bn2kb(pmp, bn); 583 DPRINTF(("%s(newcluster %lu, bn=%lu, lbn=%lu)\n", __func__, newcluster, 584 bn, lbn)); 585 /* always succeeds */ 586 bp = getblk(pmp->pm_devvp, lbn, pmp->pm_bpcluster, 0, 0); 587 memset(bp->b_data, 0, pmp->pm_bpcluster); 588 memcpy(bp->b_data, &dosdirtemplate, sizeof dosdirtemplate); 589 denp = (struct direntry *)bp->b_data; 590 putushort(denp[0].deStartCluster, newcluster); 591 putushort(denp[0].deCDate, ndirent.de_CDate); 592 putushort(denp[0].deCTime, ndirent.de_CTime); 593 denp[0].deCHundredth = ndirent.de_CHun; 594 putushort(denp[0].deADate, ndirent.de_ADate); 595 putushort(denp[0].deMDate, ndirent.de_MDate); 596 putushort(denp[0].deMTime, ndirent.de_MTime); 597 pcl = pdep->de_StartCluster; 598 DPRINTF(("%s(pcl %lu, rootdirblk=%lu)\n", __func__, pcl, 599 pmp->pm_rootdirblk)); 600 if (FAT32(pmp) && pcl == pmp->pm_rootdirblk) 601 pcl = 0; 602 putushort(denp[1].deStartCluster, pcl); 603 putushort(denp[1].deCDate, ndirent.de_CDate); 604 putushort(denp[1].deCTime, ndirent.de_CTime); 605 denp[1].deCHundredth = ndirent.de_CHun; 606 putushort(denp[1].deADate, ndirent.de_ADate); 607 putushort(denp[1].deMDate, ndirent.de_MDate); 608 putushort(denp[1].deMTime, ndirent.de_MTime); 609 if (FAT32(pmp)) { 610 putushort(denp[0].deHighClust, newcluster >> 16); 611 putushort(denp[1].deHighClust, pdep->de_StartCluster >> 16); 612 } else { 613 putushort(denp[0].deHighClust, 0); 614 putushort(denp[1].deHighClust, 0); 615 } 616 617 if ((error = bwrite(bp)) != 0) 618 goto bad; 619 620 /* 621 * Now build up a directory entry pointing to the newly allocated 622 * cluster. This will be written to an empty slot in the parent 623 * directory. 624 */ 625 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 626 goto bad; 627 628 ndirent.de_Attributes = ATTR_DIRECTORY; 629 ndirent.de_StartCluster = newcluster; 630 ndirent.de_FileSize = 0; 631 ndirent.de_dev = pdep->de_dev; 632 ndirent.de_devvp = pdep->de_devvp; 633 ndirent.de_pmp = pdep->de_pmp; 634 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 635 goto bad; 636 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 637 goto bad; 638 if ((error = msdosfs_updatede(dep)) != 0) 639 goto bad; 640 return dep; 641 642 bad: 643 clusterfree(pmp, newcluster, NULL); 644 bad2: 645 errno = error; 646 return NULL; 647 } 648