1 /*-
2 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
3 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
4 * All rights reserved.
5 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by TooLs GmbH.
18 * 4. The name of TooLs GmbH may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
27 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
28 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
29 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
30 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32 /*
33 * Written by Paul Popelka (paulp@uts.amdahl.com)
34 *
35 * You can do anything you want with this software, just don't say you wrote
36 * it, and don't remove this notice.
37 *
38 * This software is provided "as is".
39 *
40 * The author supplies this software to be publicly redistributed on the
41 * understanding that the author is not responsible for the correct
42 * functioning of this software in any circumstances and is not liable for
43 * any damages caused by this software.
44 *
45 * October 1992
46 */
47
48 #if HAVE_NBTOOL_CONFIG_H
49 #include "nbtool_config.h"
50 #endif
51
52 #include <sys/cdefs.h>
53 __KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.13 2022/04/09 10:05:35 riastradh Exp $");
54
55 #include <sys/param.h>
56
57 #include <ffs/buf.h>
58
59 #include <fs/msdosfs/bpb.h>
60 #include <fs/msdosfs/bootsect.h>
61 #include <fs/msdosfs/direntry.h>
62 #include <fs/msdosfs/denode.h>
63 #include <fs/msdosfs/msdosfsmount.h>
64 #include <fs/msdosfs/fat.h>
65
66 #include <stdio.h>
67 #include <errno.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <util.h>
71 #include <strings.h>
72
73 #include "makefs.h"
74 #include "msdos.h"
75 #include "mkfs_msdos.h"
76
77 #ifdef MSDOSFS_DEBUG
78 #define DPRINTF(a) printf a
79 #else
80 #define DPRINTF(a)
81 #endif
82
83 struct msdosfsmount *
msdosfs_mount(struct vnode * devvp,int flags)84 msdosfs_mount(struct vnode *devvp, int flags)
85 {
86 struct msdosfsmount *pmp = NULL;
87 struct buf *bp;
88 union bootsector *bsp;
89 struct byte_bpb33 *b33;
90 struct byte_bpb50 *b50;
91 struct byte_bpb710 *b710;
92 uint8_t SecPerClust;
93 int ronly = 0, error, tmp;
94 int bsize;
95 struct msdos_options *m = devvp->fs->fs_specific;
96 uint64_t psize = m->create_size;
97 unsigned secsize = 512;
98
99 DPRINTF(("%s(bread 0)\n", __func__));
100 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0)
101 goto error_exit;
102
103 bsp = (union bootsector *)bp->b_data;
104 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
105 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
106 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
107
108 if (!(flags & MSDOSFSMNT_GEMDOSFS)) {
109 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
110 || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
111 DPRINTF(("bootsig0 %d bootsig1 %d\n",
112 bsp->bs50.bsBootSectSig0,
113 bsp->bs50.bsBootSectSig1));
114 error = EINVAL;
115 goto error_exit;
116 }
117 bsize = 0;
118 } else
119 bsize = 512;
120
121 pmp = ecalloc(1, sizeof *pmp);
122 /*
123 * Compute several useful quantities from the bpb in the
124 * bootsector. Copy in the dos 5 variant of the bpb then fix up
125 * the fields that are different between dos 5 and dos 3.3.
126 */
127 SecPerClust = b50->bpbSecPerClust;
128 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
129 pmp->pm_ResSectors = getushort(b50->bpbResSectors);
130 pmp->pm_FATs = b50->bpbFATs;
131 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
132 pmp->pm_Sectors = getushort(b50->bpbSectors);
133 pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
134 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
135 pmp->pm_Heads = getushort(b50->bpbHeads);
136 pmp->pm_Media = b50->bpbMedia;
137
138 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, "
139 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n",
140 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs,
141 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs,
142 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media));
143 if (!(flags & MSDOSFSMNT_GEMDOSFS)) {
144 /* XXX - We should probably check more values here */
145 if (!pmp->pm_BytesPerSec || !SecPerClust
146 || pmp->pm_SecPerTrack > 63) {
147 DPRINTF(("bytespersec %d secperclust %d "
148 "secpertrack %d\n",
149 pmp->pm_BytesPerSec, SecPerClust,
150 pmp->pm_SecPerTrack));
151 error = EINVAL;
152 goto error_exit;
153 }
154 }
155
156 pmp->pm_flags = flags & MSDOSFSMNT_MNTOPT;
157 if (pmp->pm_flags & MSDOSFSMNT_GEMDOSFS)
158 pmp->pm_flags |= MSDOSFSMNT_NOWIN95;
159 if (pmp->pm_flags & MSDOSFSMNT_NOWIN95)
160 pmp->pm_flags |= MSDOSFSMNT_SHORTNAME;
161
162 if (pmp->pm_Sectors == 0) {
163 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
164 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
165 } else {
166 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
167 pmp->pm_HugeSectors = pmp->pm_Sectors;
168 }
169
170 if (pmp->pm_RootDirEnts == 0) {
171 unsigned short vers = getushort(b710->bpbFSVers);
172 /*
173 * Some say that bsBootSectSig[23] must be zero, but
174 * Windows does not require this and some digital cameras
175 * do not set these to zero. Therefore, do not insist.
176 */
177 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
178 DPRINTF(("sectors %d fatsecs %lu vers %d\n",
179 pmp->pm_Sectors, pmp->pm_FATsecs, vers));
180 error = EINVAL;
181 goto error_exit;
182 }
183 pmp->pm_fatmask = FAT32_MASK;
184 pmp->pm_fatmult = 4;
185 pmp->pm_fatdiv = 1;
186 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
187
188 /* mirrorring is enabled if the FATMIRROR bit is not set */
189 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
190 pmp->pm_flags |= MSDOSFS_FATMIRROR;
191 else
192 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
193 } else
194 pmp->pm_flags |= MSDOSFS_FATMIRROR;
195
196 if (flags & MSDOSFSMNT_GEMDOSFS) {
197 if (FAT32(pmp)) {
198 DPRINTF(("FAT32 for GEMDOS\n"));
199 /*
200 * GEMDOS doesn't know FAT32.
201 */
202 error = EINVAL;
203 goto error_exit;
204 }
205
206 /*
207 * Check a few values (could do some more):
208 * - logical sector size: power of 2, >= block size
209 * - sectors per cluster: power of 2, >= 1
210 * - number of sectors: >= 1, <= size of partition
211 */
212 if ( (SecPerClust == 0)
213 || (SecPerClust & (SecPerClust - 1))
214 || (pmp->pm_BytesPerSec < bsize)
215 || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
216 || (pmp->pm_HugeSectors == 0)
217 || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
218 > psize)) {
219 DPRINTF(("consistency checks for GEMDOS\n"));
220 error = EINVAL;
221 goto error_exit;
222 }
223 /*
224 * XXX - Many parts of the msdosfs driver seem to assume that
225 * the number of bytes per logical sector (BytesPerSec) will
226 * always be the same as the number of bytes per disk block
227 * Let's pretend it is.
228 */
229 tmp = pmp->pm_BytesPerSec / bsize;
230 pmp->pm_BytesPerSec = bsize;
231 pmp->pm_HugeSectors *= tmp;
232 pmp->pm_HiddenSects *= tmp;
233 pmp->pm_ResSectors *= tmp;
234 pmp->pm_Sectors *= tmp;
235 pmp->pm_FATsecs *= tmp;
236 SecPerClust *= tmp;
237 }
238
239 /* Check that fs has nonzero FAT size */
240 if (pmp->pm_FATsecs == 0) {
241 DPRINTF(("FATsecs is 0\n"));
242 error = EINVAL;
243 goto error_exit;
244 }
245
246 pmp->pm_fatblk = pmp->pm_ResSectors;
247 if (FAT32(pmp)) {
248 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
249 pmp->pm_firstcluster = pmp->pm_fatblk
250 + (pmp->pm_FATs * pmp->pm_FATsecs);
251 pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
252 } else {
253 pmp->pm_rootdirblk = pmp->pm_fatblk +
254 (pmp->pm_FATs * pmp->pm_FATsecs);
255 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
256 + pmp->pm_BytesPerSec - 1)
257 / pmp->pm_BytesPerSec;/* in sectors */
258 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
259 }
260
261 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
262 SecPerClust;
263 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
264 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
265
266 if (flags & MSDOSFSMNT_GEMDOSFS) {
267 if (pmp->pm_nmbrofclusters <= (0xff0 - 2)) {
268 pmp->pm_fatmask = FAT12_MASK;
269 pmp->pm_fatmult = 3;
270 pmp->pm_fatdiv = 2;
271 } else {
272 pmp->pm_fatmask = FAT16_MASK;
273 pmp->pm_fatmult = 2;
274 pmp->pm_fatdiv = 1;
275 }
276 } else if (pmp->pm_fatmask == 0) {
277 if (pmp->pm_maxcluster
278 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
279 /*
280 * This will usually be a floppy disk. This size makes
281 * sure that one FAT entry will not be split across
282 * multiple blocks.
283 */
284 pmp->pm_fatmask = FAT12_MASK;
285 pmp->pm_fatmult = 3;
286 pmp->pm_fatdiv = 2;
287 } else {
288 pmp->pm_fatmask = FAT16_MASK;
289 pmp->pm_fatmult = 2;
290 pmp->pm_fatdiv = 1;
291 }
292 }
293 if (FAT12(pmp))
294 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
295 else
296 pmp->pm_fatblocksize = MAXBSIZE;
297
298 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
299 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
300
301 /*
302 * Compute mask and shift value for isolating cluster relative byte
303 * offsets and cluster numbers from a file offset.
304 */
305 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
306 pmp->pm_crbomask = pmp->pm_bpcluster - 1;
307 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
308
309 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, "
310 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, "
311 "cnshift=%lu)\n",
312 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv,
313 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift,
314 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift));
315 /*
316 * Check for valid cluster size
317 * must be a power of 2
318 */
319 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
320 DPRINTF(("bpcluster %lu cnshift %lu\n",
321 pmp->pm_bpcluster, pmp->pm_cnshift));
322 error = EINVAL;
323 goto error_exit;
324 }
325
326 /*
327 * Release the bootsector buffer.
328 */
329 brelse(bp, BC_AGE);
330 bp = NULL;
331
332 /*
333 * Check FSInfo.
334 */
335 if (pmp->pm_fsinfo) {
336 struct fsinfo *fp;
337
338 /*
339 * XXX If the fsinfo block is stored on media with
340 * 2KB or larger sectors, is the fsinfo structure
341 * padded at the end or in the middle?
342 */
343 DPRINTF(("%s(bread %lu)\n", __func__,
344 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo)));
345 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
346 pmp->pm_BytesPerSec, 0, &bp)) != 0)
347 goto error_exit;
348 fp = (struct fsinfo *)bp->b_data;
349 if (!memcmp(fp->fsisig1, "RRaA", 4)
350 && !memcmp(fp->fsisig2, "rrAa", 4)
351 && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
352 && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
353 pmp->pm_nxtfree = getulong(fp->fsinxtfree);
354 else
355 pmp->pm_fsinfo = 0;
356 brelse(bp, 0);
357 bp = NULL;
358 }
359
360 /*
361 * Check and validate (or perhaps invalidate?) the fsinfo structure?
362 * XXX
363 */
364 if (pmp->pm_fsinfo) {
365 if ((pmp->pm_nxtfree == 0xffffffffUL) ||
366 (pmp->pm_nxtfree > pmp->pm_maxcluster))
367 pmp->pm_fsinfo = 0;
368 }
369
370 /*
371 * Allocate memory for the bitmap of allocated clusters, and then
372 * fill it in.
373 */
374 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap),
375 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS));
376 /*
377 * fillinusemap() needs pm_devvp.
378 */
379 pmp->pm_dev = 0;
380 pmp->pm_devvp = devvp;
381
382 /*
383 * Have the inuse map filled in.
384 */
385 if ((error = msdosfs_fillinusemap(pmp)) != 0) {
386 DPRINTF(("fillinusemap %d\n", error));
387 goto error_exit;
388 }
389
390 /*
391 * Finish up.
392 */
393 if (ronly)
394 pmp->pm_flags |= MSDOSFSMNT_RONLY;
395 else
396 pmp->pm_fmod = 1;
397
398 /*
399 * If we ever do quotas for DOS filesystems this would be a place
400 * to fill in the info in the msdosfsmount structure. You dolt,
401 * quotas on dos filesystems make no sense because files have no
402 * owners on dos filesystems. of course there is some empty space
403 * in the directory entry where we could put uid's and gid's.
404 */
405
406 return pmp;
407
408 error_exit:
409 if (bp)
410 brelse(bp, BC_AGE);
411 if (pmp) {
412 if (pmp->pm_inusemap)
413 free(pmp->pm_inusemap);
414 free(pmp);
415 }
416 errno = error;
417 return NULL;
418 }
419
420 int
msdosfs_root(struct msdosfsmount * pmp,struct vnode * vp)421 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) {
422 struct denode *ndep;
423 int error;
424
425 *vp = *pmp->pm_devvp;
426 if ((error = msdosfs_deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS,
427 &ndep)) != 0) {
428 errno = error;
429 return -1;
430 }
431 vp->v_data = ndep;
432 return 0;
433 }
434