1 /* $NetBSD: msdosfs_vnops.c,v 1.19 2017/04/13 17:10:12 christos Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. 7 * Copyright (C) 1994, 1995, 1997 TooLs GmbH. 8 * All rights reserved. 9 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by TooLs GmbH. 22 * 4. The name of TooLs GmbH may not be used to endorse or promote products 23 * derived from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 30 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 31 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 32 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 33 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 34 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 /*- 37 * Written by Paul Popelka (paulp@uts.amdahl.com) 38 * 39 * You can do anything you want with this software, just don't say you wrote 40 * it, and don't remove this notice. 41 * 42 * This software is provided "as is". 43 * 44 * The author supplies this software to be publicly redistributed on the 45 * understanding that the author is not responsible for the correct 46 * functioning of this software in any circumstances and is not liable for 47 * any damages caused by this software. 48 * 49 * October 1992 50 */ 51 52 #include <sys/param.h> 53 #include <sys/errno.h> 54 #include <sys/mman.h> 55 #include <sys/time.h> 56 57 #include <fcntl.h> 58 #include <stdbool.h> 59 #include <stdio.h> 60 #include <string.h> 61 #include <time.h> 62 #include <unistd.h> 63 64 #include <fs/msdosfs/bpb.h> 65 #include "msdos/denode.h" 66 #include <fs/msdosfs/fat.h> 67 #include <fs/msdosfs/msdosfsmount.h> 68 69 #include "makefs.h" 70 #include "msdos.h" 71 72 /* 73 * Some general notes: 74 * 75 * In the ufs filesystem the inodes, superblocks, and indirect blocks are 76 * read/written using the vnode for the filesystem. Blocks that represent 77 * the contents of a file are read/written using the vnode for the file 78 * (including directories when they are read/written as files). This 79 * presents problems for the dos filesystem because data that should be in 80 * an inode (if dos had them) resides in the directory itself. Since we 81 * must update directory entries without the benefit of having the vnode 82 * for the directory we must use the vnode for the filesystem. This means 83 * that when a directory is actually read/written (via read, write, or 84 * readdir, or seek) we must use the vnode for the filesystem instead of 85 * the vnode for the directory as would happen in ufs. This is to insure we 86 * retrieve the correct block from the buffer cache since the hash value is 87 * based upon the vnode address and the desired block number. 88 */ 89 90 static int msdosfs_wfile(const char *, struct denode *, fsnode *); 91 static void unix2fattime(const struct timespec *tsp, uint16_t *ddp, 92 uint16_t *dtp); 93 94 static void 95 msdosfs_times(struct denode *dep, const struct stat *st) 96 { 97 98 #if HAVE_STRUCT_STAT_BIRTHTIME 99 unix2fattime(&st->st_birthtim, &dep->de_CDate, &dep->de_CTime); 100 #else 101 unix2fattime(&st->st_ctim, &dep->de_CDate, &dep->de_CTime); 102 #endif 103 unix2fattime(&st->st_atim, &dep->de_ADate, NULL); 104 unix2fattime(&st->st_mtim, &dep->de_MDate, &dep->de_MTime); 105 } 106 107 static void 108 unix2fattime(const struct timespec *tsp, uint16_t *ddp, uint16_t *dtp) 109 { 110 time_t t1; 111 struct tm lt = {0}; 112 113 t1 = tsp->tv_sec; 114 gmtime_r(&t1, <); 115 116 unsigned long fat_time = ((lt.tm_year - 80) << 25) | 117 ((lt.tm_mon + 1) << 21) | 118 (lt.tm_mday << 16) | 119 (lt.tm_hour << 11) | 120 (lt.tm_min << 5) | 121 (lt.tm_sec >> 1); 122 123 if (ddp != NULL) 124 *ddp = (uint16_t)(fat_time >> 16); 125 if (dtp != NULL) 126 *dtp = (uint16_t)fat_time; 127 } 128 129 /* 130 * When we search a directory the blocks containing directory entries are 131 * read and examined. The directory entries contain information that would 132 * normally be in the inode of a unix filesystem. This means that some of 133 * a directory's contents may also be in memory resident denodes (sort of 134 * an inode). This can cause problems if we are searching while some other 135 * process is modifying a directory. To prevent one process from accessing 136 * incompletely modified directory information we depend upon being the 137 * sole owner of a directory block. bread/brelse provide this service. 138 * This being the case, when a process modifies a directory it must first 139 * acquire the disk block that contains the directory entry to be modified. 140 * Then update the disk block and the denode, and then write the disk block 141 * out to disk. This way disk blocks containing directory entries and in 142 * memory denode's will be in synch. 143 */ 144 static int 145 msdosfs_findslot(struct denode *dp, struct componentname *cnp) 146 { 147 daddr_t bn; 148 int error; 149 int slotcount; 150 int slotoffset = 0; 151 int frcn; 152 u_long cluster; 153 int blkoff; 154 u_int diroff; 155 int blsize; 156 struct msdosfsmount *pmp; 157 struct m_buf *bp = 0; 158 struct direntry *dep; 159 u_char dosfilename[12]; 160 int wincnt = 1; 161 int chksum = -1, chksum_ok; 162 int olddos = 1; 163 164 pmp = dp->de_pmp; 165 166 switch (unix2dosfn((const u_char *)cnp->cn_nameptr, dosfilename, 167 cnp->cn_namelen, 0)) { 168 case 0: 169 return (EINVAL); 170 case 1: 171 break; 172 case 2: 173 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 174 cnp->cn_namelen) + 1; 175 break; 176 case 3: 177 olddos = 0; 178 wincnt = winSlotCnt((const u_char *)cnp->cn_nameptr, 179 cnp->cn_namelen) + 1; 180 break; 181 } 182 183 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 184 wincnt = 1; 185 186 /* 187 * Suppress search for slots unless creating 188 * file and at end of pathname, in which case 189 * we watch for a place to put the new file in 190 * case it doesn't already exist. 191 */ 192 slotcount = 0; 193 MSDOSFS_DPRINTF(("%s(): dos filename: %s\n", __func__, dosfilename)); 194 /* 195 * Search the directory pointed at by vdp for the name pointed at 196 * by cnp->cn_nameptr. 197 */ 198 /* 199 * The outer loop ranges over the clusters that make up the 200 * directory. Note that the root directory is different from all 201 * other directories. It has a fixed number of blocks that are not 202 * part of the pool of allocatable clusters. So, we treat it a 203 * little differently. The root directory starts at "cluster" 0. 204 */ 205 diroff = 0; 206 for (frcn = 0; diroff < dp->de_FileSize; frcn++) { 207 if ((error = pcbmap(dp, frcn, &bn, &cluster, &blsize)) != 0) { 208 if (error == E2BIG) 209 break; 210 return (error); 211 } 212 error = bread((void *)pmp->pm_devvp, bn, blsize, 0, &bp); 213 if (error) { 214 return (error); 215 } 216 for (blkoff = 0; blkoff < blsize; 217 blkoff += sizeof(struct direntry), 218 diroff += sizeof(struct direntry)) { 219 dep = (struct direntry *)(bp->b_data + blkoff); 220 /* 221 * If the slot is empty and we are still looking 222 * for an empty then remember this one. If the 223 * slot is not empty then check to see if it 224 * matches what we are looking for. If the slot 225 * has never been filled with anything, then the 226 * remainder of the directory has never been used, 227 * so there is no point in searching it. 228 */ 229 if (dep->deName[0] == SLOT_EMPTY || 230 dep->deName[0] == SLOT_DELETED) { 231 /* 232 * Drop memory of previous long matches 233 */ 234 chksum = -1; 235 236 if (slotcount < wincnt) { 237 slotcount++; 238 slotoffset = diroff; 239 } 240 if (dep->deName[0] == SLOT_EMPTY) { 241 brelse(bp); 242 goto notfound; 243 } 244 } else { 245 /* 246 * If there wasn't enough space for our 247 * winentries, forget about the empty space 248 */ 249 if (slotcount < wincnt) 250 slotcount = 0; 251 252 /* 253 * Check for Win95 long filename entry 254 */ 255 if (dep->deAttributes == ATTR_WIN95) { 256 if (pmp->pm_flags & MSDOSFSMNT_SHORTNAME) 257 continue; 258 259 chksum = winChkName( 260 (const u_char *)cnp->cn_nameptr, 261 cnp->cn_namelen, 262 (struct winentry *)dep, chksum); 263 continue; 264 } 265 266 /* 267 * Ignore volume labels (anywhere, not just 268 * the root directory). 269 */ 270 if (dep->deAttributes & ATTR_VOLUME) { 271 chksum = -1; 272 continue; 273 } 274 275 /* 276 * Check for a checksum or name match 277 */ 278 chksum_ok = (chksum == winChksum(dep->deName)); 279 if (!chksum_ok 280 && (!olddos || memcmp(dosfilename, dep->deName, 11))) { 281 chksum = -1; 282 continue; 283 } 284 MSDOSFS_DPRINTF(("%s(): match blkoff %d, diroff %u\n", 285 __func__, blkoff, diroff)); 286 /* 287 * Remember where this directory 288 * entry came from for whoever did 289 * this lookup. 290 */ 291 dp->de_fndoffset = diroff; 292 dp->de_fndcnt = 0; 293 294 return EEXIST; 295 } 296 } /* for (blkoff = 0; .... */ 297 /* 298 * Release the buffer holding the directory cluster just 299 * searched. 300 */ 301 brelse(bp); 302 } /* for (frcn = 0; ; frcn++) */ 303 304 notfound: 305 /* 306 * We hold no disk buffers at this point. 307 */ 308 309 /* 310 * If we get here we didn't find the entry we were looking for. But 311 * that's ok if we are creating or renaming and are at the end of 312 * the pathname and the directory hasn't been removed. 313 */ 314 MSDOSFS_DPRINTF(("%s(): refcnt %ld, slotcount %d, slotoffset %d\n", 315 __func__, dp->de_refcnt, slotcount, slotoffset)); 316 /* 317 * Fixup the slot description to point to the place where 318 * we might put the new DOS direntry (putting the Win95 319 * long name entries before that) 320 */ 321 if (!slotcount) { 322 slotcount = 1; 323 slotoffset = diroff; 324 } 325 if (wincnt > slotcount) { 326 slotoffset += sizeof(struct direntry) * (wincnt - slotcount); 327 } 328 329 /* 330 * Return an indication of where the new directory 331 * entry should be put. 332 */ 333 dp->de_fndoffset = slotoffset; 334 dp->de_fndcnt = wincnt - 1; 335 336 /* 337 * We return with the directory locked, so that 338 * the parameters we set up above will still be 339 * valid if we actually decide to do a direnter(). 340 * We return ni_vp == NULL to indicate that the entry 341 * does not currently exist; we leave a pointer to 342 * the (locked) directory inode in ndp->ni_dvp. 343 * 344 * NB - if the directory is unlocked, then this 345 * information cannot be used. 346 */ 347 return 0; 348 } 349 350 /* 351 * Create a regular file. On entry the directory to contain the file being 352 * created is locked. We must release before we return. 353 */ 354 struct denode * 355 msdosfs_mkfile(const char *path, struct denode *pdep, fsnode *node) 356 { 357 struct componentname cn; 358 struct denode ndirent; 359 struct denode *dep; 360 int error; 361 struct stat *st = &node->inode->st; 362 363 cn.cn_nameptr = node->name; 364 cn.cn_namelen = strlen(node->name); 365 366 MSDOSFS_DPRINTF(("%s(name %s, mode 0%o size %zu)\n", 367 __func__, node->name, st->st_mode, (size_t)st->st_size)); 368 369 /* 370 * If this is the root directory and there is no space left we 371 * can't do anything. This is because the root directory can not 372 * change size. 373 */ 374 if (pdep->de_StartCluster == MSDOSFSROOT 375 && pdep->de_fndoffset >= pdep->de_FileSize) { 376 error = ENOSPC; 377 goto bad; 378 } 379 380 /* 381 * Create a directory entry for the file, then call createde() to 382 * have it installed. NOTE: DOS files are always executable. We 383 * use the absence of the owner write bit to make the file 384 * readonly. 385 */ 386 memset(&ndirent, 0, sizeof(ndirent)); 387 if ((error = uniqdosname(pdep, &cn, ndirent.de_Name)) != 0) 388 goto bad; 389 390 ndirent.de_Attributes = (st->st_mode & S_IWUSR) ? 391 ATTR_ARCHIVE : ATTR_ARCHIVE | ATTR_READONLY; 392 ndirent.de_StartCluster = 0; 393 ndirent.de_FileSize = 0; 394 ndirent.de_pmp = pdep->de_pmp; 395 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 396 msdosfs_times(&ndirent, &node->inode->st); 397 398 if ((error = msdosfs_findslot(pdep, &cn)) != 0) 399 goto bad; 400 if ((error = createde(&ndirent, pdep, &dep, &cn)) != 0) 401 goto bad; 402 if ((error = msdosfs_wfile(path, dep, node)) != 0) 403 goto bad; 404 return dep; 405 406 bad: 407 errno = error; 408 return NULL; 409 } 410 static int 411 msdosfs_updatede(struct denode *dep) 412 { 413 struct m_buf *bp; 414 struct direntry *dirp; 415 int error; 416 417 dep->de_flag &= ~DE_MODIFIED; 418 error = m_readde(dep, &bp, &dirp); 419 if (error) 420 return error; 421 DE_EXTERNALIZE(dirp, dep); 422 error = bwrite(bp); 423 return error; 424 } 425 426 /* 427 * Write data to a file or directory. 428 */ 429 static int 430 msdosfs_wfile(const char *path, struct denode *dep, fsnode *node) 431 { 432 int error, fd; 433 size_t osize = dep->de_FileSize; 434 struct stat *st = &node->inode->st; 435 size_t nsize, offs; 436 struct msdosfsmount *pmp = dep->de_pmp; 437 struct m_buf *bp; 438 char *dat; 439 u_long cn = 0; 440 441 error = 0; /* XXX: gcc/vax */ 442 MSDOSFS_DPRINTF(("%s(diroff %lu, dirclust %lu, startcluster %lu)\n", 443 __func__, dep->de_diroffset, dep->de_dirclust, 444 dep->de_StartCluster)); 445 if (st->st_size == 0) 446 return 0; 447 448 /* Don't bother to try to write files larger than the fs limit */ 449 if (st->st_size > MSDOSFS_FILESIZE_MAX) 450 return EFBIG; 451 452 nsize = st->st_size; 453 MSDOSFS_DPRINTF(("%s(nsize=%zu, osize=%zu)\n", __func__, nsize, osize)); 454 if (nsize > osize) { 455 if ((error = deextend(dep, nsize, NULL)) != 0) 456 return error; 457 if ((error = msdosfs_updatede(dep)) != 0) 458 return error; 459 } 460 461 if ((fd = open(path, O_RDONLY)) == -1) { 462 error = errno; 463 fprintf(stderr, "open %s: %s\n", path, strerror(error)); 464 return error; 465 } 466 467 if ((dat = mmap(0, nsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0)) 468 == MAP_FAILED) { 469 error = errno; 470 fprintf(stderr, "%s: mmap %s: %s\n", __func__, node->name, 471 strerror(error)); 472 close(fd); 473 goto out; 474 } 475 close(fd); 476 477 for (offs = 0; offs < nsize;) { 478 int blsize, cpsize; 479 daddr_t bn; 480 u_long on = offs & pmp->pm_crbomask; 481 482 if ((error = pcbmap(dep, cn++, &bn, NULL, &blsize)) != 0) { 483 MSDOSFS_DPRINTF(("%s: pcbmap %lu", 484 __func__, (unsigned long)bn)); 485 goto out; 486 } 487 488 MSDOSFS_DPRINTF(("%s(cn=%lu, bn=%llu, blsize=%d)\n", 489 __func__, cn, (unsigned long long)bn, blsize)); 490 if ((error = bread((void *)pmp->pm_devvp, bn, blsize, 0, 491 &bp)) != 0) { 492 MSDOSFS_DPRINTF(("bread %d\n", error)); 493 goto out; 494 } 495 cpsize = MIN((nsize - offs), blsize - on); 496 memcpy(bp->b_data + on, dat + offs, cpsize); 497 bwrite(bp); 498 offs += cpsize; 499 } 500 501 munmap(dat, nsize); 502 return 0; 503 out: 504 munmap(dat, nsize); 505 return error; 506 } 507 508 static const struct { 509 struct direntry dot; 510 struct direntry dotdot; 511 } dosdirtemplate = { 512 { ". ", /* the . entry */ 513 ATTR_DIRECTORY, /* file attribute */ 514 0, /* reserved */ 515 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 516 { 0, 0 }, /* access date */ 517 { 0, 0 }, /* high bits of start cluster */ 518 { 210, 4 }, { 210, 4 }, /* modify time & date */ 519 { 0, 0 }, /* startcluster */ 520 { 0, 0, 0, 0 } /* filesize */ 521 }, 522 { ".. ", /* the .. entry */ 523 ATTR_DIRECTORY, /* file attribute */ 524 0, /* reserved */ 525 0, { 0, 0 }, { 0, 0 }, /* create time & date */ 526 { 0, 0 }, /* access date */ 527 { 0, 0 }, /* high bits of start cluster */ 528 { 210, 4 }, { 210, 4 }, /* modify time & date */ 529 { 0, 0 }, /* startcluster */ 530 { 0, 0, 0, 0 } /* filesize */ 531 } 532 }; 533 534 struct denode * 535 msdosfs_mkdire(const char *path __unused, struct denode *pdep, fsnode *node) 536 { 537 struct denode ndirent; 538 struct denode *dep; 539 struct componentname cn; 540 struct msdosfsmount *pmp = pdep->de_pmp; 541 int error; 542 u_long newcluster, pcl, bn; 543 struct direntry *denp; 544 struct m_buf *bp; 545 546 cn.cn_nameptr = node->name; 547 cn.cn_namelen = strlen(node->name); 548 /* 549 * If this is the root directory and there is no space left we 550 * can't do anything. This is because the root directory can not 551 * change size. 552 */ 553 if (pdep->de_StartCluster == MSDOSFSROOT 554 && pdep->de_fndoffset >= pdep->de_FileSize) { 555 error = ENOSPC; 556 goto bad2; 557 } 558 559 /* 560 * Allocate a cluster to hold the about to be created directory. 561 */ 562 error = clusteralloc(pmp, 0, 1, CLUST_EOFE, &newcluster, NULL); 563 if (error) 564 goto bad2; 565 566 memset(&ndirent, 0, sizeof(ndirent)); 567 ndirent.de_pmp = pmp; 568 ndirent.de_flag = DE_ACCESS | DE_CREATE | DE_UPDATE; 569 msdosfs_times(&ndirent, &node->inode->st); 570 571 /* 572 * Now fill the cluster with the "." and ".." entries. And write 573 * the cluster to disk. This way it is there for the parent 574 * directory to be pointing at if there were a crash. 575 */ 576 bn = cntobn(pmp, newcluster); 577 MSDOSFS_DPRINTF(("%s(newcluster %lu, bn=%lu)\n", 578 __func__, newcluster, bn)); 579 /* always succeeds */ 580 bp = getblk((void *)pmp->pm_devvp, bn, pmp->pm_bpcluster, 0, 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 MSDOSFS_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_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); 636 bad2: 637 errno = error; 638 return NULL; 639 } 640