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 1.9 2015/03/29 05:52:59 agc 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
72 #include "makefs.h"
73 #include "msdos.h"
74 #include "mkfs_msdos.h"
75
76 #ifdef MSDOSFS_DEBUG
77 #define DPRINTF(a) printf a
78 #else
79 #define DPRINTF(a)
80 #endif
81
82 struct msdosfsmount *
msdosfs_mount(struct vnode * devvp,int flags)83 msdosfs_mount(struct vnode *devvp, int flags)
84 {
85 struct msdosfsmount *pmp = NULL;
86 struct buf *bp;
87 union bootsector *bsp;
88 struct byte_bpb33 *b33;
89 struct byte_bpb50 *b50;
90 struct byte_bpb710 *b710;
91 uint8_t SecPerClust;
92 int ronly = 0, error, tmp;
93 int bsize;
94 struct msdos_options *m = devvp->fs->fs_specific;
95 uint64_t psize = m->create_size;
96 unsigned secsize = 512;
97
98 DPRINTF(("%s(bread 0)\n", __func__));
99 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0)
100 goto error_exit;
101
102 bsp = (union bootsector *)bp->b_data;
103 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
104 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
105 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
106
107 if (!(flags & MSDOSFSMNT_GEMDOSFS)) {
108 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
109 || bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
110 DPRINTF(("bootsig0 %d bootsig1 %d\n",
111 bsp->bs50.bsBootSectSig0,
112 bsp->bs50.bsBootSectSig1));
113 error = EINVAL;
114 goto error_exit;
115 }
116 bsize = 0;
117 } else
118 bsize = 512;
119
120 pmp = ecalloc(1, sizeof *pmp);
121 /*
122 * Compute several useful quantities from the bpb in the
123 * bootsector. Copy in the dos 5 variant of the bpb then fix up
124 * the fields that are different between dos 5 and dos 3.3.
125 */
126 SecPerClust = b50->bpbSecPerClust;
127 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
128 pmp->pm_ResSectors = getushort(b50->bpbResSectors);
129 pmp->pm_FATs = b50->bpbFATs;
130 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
131 pmp->pm_Sectors = getushort(b50->bpbSectors);
132 pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
133 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
134 pmp->pm_Heads = getushort(b50->bpbHeads);
135 pmp->pm_Media = b50->bpbMedia;
136
137 DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, RootDirEnts=%u, "
138 "Sectors=%u, FATsecs=%lu, SecPerTrack=%u, Heads=%u, Media=%u)\n",
139 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors, pmp->pm_FATs,
140 pmp->pm_RootDirEnts, pmp->pm_Sectors, pmp->pm_FATsecs,
141 pmp->pm_SecPerTrack, pmp->pm_Heads, pmp->pm_Media));
142 if (!(flags & MSDOSFSMNT_GEMDOSFS)) {
143 /* XXX - We should probably check more values here */
144 if (!pmp->pm_BytesPerSec || !SecPerClust
145 || pmp->pm_SecPerTrack > 63) {
146 DPRINTF(("bytespersec %d secperclust %d "
147 "secpertrack %d\n",
148 pmp->pm_BytesPerSec, SecPerClust,
149 pmp->pm_SecPerTrack));
150 error = EINVAL;
151 goto error_exit;
152 }
153 }
154
155 if (pmp->pm_Sectors == 0) {
156 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
157 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
158 } else {
159 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
160 pmp->pm_HugeSectors = pmp->pm_Sectors;
161 }
162
163 if (pmp->pm_RootDirEnts == 0) {
164 unsigned short vers = getushort(b710->bpbFSVers);
165 /*
166 * Some say that bsBootSectSig[23] must be zero, but
167 * Windows does not require this and some digital cameras
168 * do not set these to zero. Therefore, do not insist.
169 */
170 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
171 DPRINTF(("sectors %d fatsecs %lu vers %d\n",
172 pmp->pm_Sectors, pmp->pm_FATsecs, vers));
173 error = EINVAL;
174 goto error_exit;
175 }
176 pmp->pm_fatmask = FAT32_MASK;
177 pmp->pm_fatmult = 4;
178 pmp->pm_fatdiv = 1;
179 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
180
181 /* mirrorring is enabled if the FATMIRROR bit is not set */
182 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
183 pmp->pm_flags |= MSDOSFS_FATMIRROR;
184 else
185 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
186 } else
187 pmp->pm_flags |= MSDOSFS_FATMIRROR;
188
189 if (flags & MSDOSFSMNT_GEMDOSFS) {
190 if (FAT32(pmp)) {
191 DPRINTF(("FAT32 for GEMDOS\n"));
192 /*
193 * GEMDOS doesn't know FAT32.
194 */
195 error = EINVAL;
196 goto error_exit;
197 }
198
199 /*
200 * Check a few values (could do some more):
201 * - logical sector size: power of 2, >= block size
202 * - sectors per cluster: power of 2, >= 1
203 * - number of sectors: >= 1, <= size of partition
204 */
205 if ( (SecPerClust == 0)
206 || (SecPerClust & (SecPerClust - 1))
207 || (pmp->pm_BytesPerSec < bsize)
208 || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
209 || (pmp->pm_HugeSectors == 0)
210 || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
211 > psize)) {
212 DPRINTF(("consistency checks for GEMDOS\n"));
213 error = EINVAL;
214 goto error_exit;
215 }
216 /*
217 * XXX - Many parts of the msdosfs driver seem to assume that
218 * the number of bytes per logical sector (BytesPerSec) will
219 * always be the same as the number of bytes per disk block
220 * Let's pretend it is.
221 */
222 tmp = pmp->pm_BytesPerSec / bsize;
223 pmp->pm_BytesPerSec = bsize;
224 pmp->pm_HugeSectors *= tmp;
225 pmp->pm_HiddenSects *= tmp;
226 pmp->pm_ResSectors *= tmp;
227 pmp->pm_Sectors *= tmp;
228 pmp->pm_FATsecs *= tmp;
229 SecPerClust *= tmp;
230 }
231
232 /* Check that fs has nonzero FAT size */
233 if (pmp->pm_FATsecs == 0) {
234 DPRINTF(("FATsecs is 0\n"));
235 error = EINVAL;
236 goto error_exit;
237 }
238
239 pmp->pm_fatblk = pmp->pm_ResSectors;
240 if (FAT32(pmp)) {
241 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
242 pmp->pm_firstcluster = pmp->pm_fatblk
243 + (pmp->pm_FATs * pmp->pm_FATsecs);
244 pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
245 } else {
246 pmp->pm_rootdirblk = pmp->pm_fatblk +
247 (pmp->pm_FATs * pmp->pm_FATsecs);
248 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
249 + pmp->pm_BytesPerSec - 1)
250 / pmp->pm_BytesPerSec;/* in sectors */
251 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
252 }
253
254 pmp->pm_nmbrofclusters = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
255 SecPerClust;
256 pmp->pm_maxcluster = pmp->pm_nmbrofclusters + 1;
257 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
258
259 if (flags & MSDOSFSMNT_GEMDOSFS) {
260 if (pmp->pm_nmbrofclusters <= (0xff0 - 2)) {
261 pmp->pm_fatmask = FAT12_MASK;
262 pmp->pm_fatmult = 3;
263 pmp->pm_fatdiv = 2;
264 } else {
265 pmp->pm_fatmask = FAT16_MASK;
266 pmp->pm_fatmult = 2;
267 pmp->pm_fatdiv = 1;
268 }
269 } else if (pmp->pm_fatmask == 0) {
270 if (pmp->pm_maxcluster
271 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
272 /*
273 * This will usually be a floppy disk. This size makes
274 * sure that one FAT entry will not be split across
275 * multiple blocks.
276 */
277 pmp->pm_fatmask = FAT12_MASK;
278 pmp->pm_fatmult = 3;
279 pmp->pm_fatdiv = 2;
280 } else {
281 pmp->pm_fatmask = FAT16_MASK;
282 pmp->pm_fatmult = 2;
283 pmp->pm_fatdiv = 1;
284 }
285 }
286 if (FAT12(pmp))
287 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
288 else
289 pmp->pm_fatblocksize = MAXBSIZE;
290
291 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
292 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
293
294 /*
295 * Compute mask and shift value for isolating cluster relative byte
296 * offsets and cluster numbers from a file offset.
297 */
298 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
299 pmp->pm_crbomask = pmp->pm_bpcluster - 1;
300 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
301
302 DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, fatblocksize=%lu, "
303 "fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, crbomask=%lu, "
304 "cnshift=%lu)\n",
305 __func__, pmp->pm_fatmask, pmp->pm_fatmult, pmp->pm_fatdiv,
306 pmp->pm_fatblocksize, pmp->pm_fatblocksec, pmp->pm_bnshift,
307 pmp->pm_bpcluster, pmp->pm_crbomask, pmp->pm_cnshift));
308 /*
309 * Check for valid cluster size
310 * must be a power of 2
311 */
312 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
313 DPRINTF(("bpcluster %lu cnshift %lu\n",
314 pmp->pm_bpcluster, pmp->pm_cnshift));
315 error = EINVAL;
316 goto error_exit;
317 }
318
319 /*
320 * Release the bootsector buffer.
321 */
322 brelse(bp, BC_AGE);
323 bp = NULL;
324
325 /*
326 * Check FSInfo.
327 */
328 if (pmp->pm_fsinfo) {
329 struct fsinfo *fp;
330
331 /*
332 * XXX If the fsinfo block is stored on media with
333 * 2KB or larger sectors, is the fsinfo structure
334 * padded at the end or in the middle?
335 */
336 DPRINTF(("%s(bread %lu)\n", __func__,
337 (unsigned long)de_bn2kb(pmp, pmp->pm_fsinfo)));
338 if ((error = bread(devvp, de_bn2kb(pmp, pmp->pm_fsinfo),
339 pmp->pm_BytesPerSec, 0, &bp)) != 0)
340 goto error_exit;
341 fp = (struct fsinfo *)bp->b_data;
342 if (!memcmp(fp->fsisig1, "RRaA", 4)
343 && !memcmp(fp->fsisig2, "rrAa", 4)
344 && !memcmp(fp->fsisig3, "\0\0\125\252", 4)
345 && !memcmp(fp->fsisig4, "\0\0\125\252", 4))
346 pmp->pm_nxtfree = getulong(fp->fsinxtfree);
347 else
348 pmp->pm_fsinfo = 0;
349 brelse(bp, 0);
350 bp = NULL;
351 }
352
353 /*
354 * Check and validate (or perhaps invalidate?) the fsinfo structure?
355 * XXX
356 */
357 if (pmp->pm_fsinfo) {
358 if ((pmp->pm_nxtfree == 0xffffffffUL) ||
359 (pmp->pm_nxtfree > pmp->pm_maxcluster))
360 pmp->pm_fsinfo = 0;
361 }
362
363 /*
364 * Allocate memory for the bitmap of allocated clusters, and then
365 * fill it in.
366 */
367 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap),
368 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS));
369 /*
370 * fillinusemap() needs pm_devvp.
371 */
372 pmp->pm_dev = 0;
373 pmp->pm_devvp = devvp;
374
375 /*
376 * Have the inuse map filled in.
377 */
378 if ((error = fillinusemap(pmp)) != 0) {
379 DPRINTF(("fillinusemap %d\n", error));
380 goto error_exit;
381 }
382
383 /*
384 * Finish up.
385 */
386 if (ronly)
387 pmp->pm_flags |= MSDOSFSMNT_RONLY;
388 else
389 pmp->pm_fmod = 1;
390
391 /*
392 * If we ever do quotas for DOS filesystems this would be a place
393 * to fill in the info in the msdosfsmount structure. You dolt,
394 * quotas on dos filesystems make no sense because files have no
395 * owners on dos filesystems. of course there is some empty space
396 * in the directory entry where we could put uid's and gid's.
397 */
398
399 return pmp;
400
401 error_exit:
402 if (bp)
403 brelse(bp, BC_AGE);
404 if (pmp) {
405 if (pmp->pm_inusemap)
406 free(pmp->pm_inusemap);
407 free(pmp);
408 }
409 errno = error;
410 return NULL;
411 }
412
413 int
msdosfs_root(struct msdosfsmount * pmp,struct vnode * vp)414 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) {
415 struct denode *ndep;
416 int error;
417
418 *vp = *pmp->pm_devvp;
419 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) {
420 errno = error;
421 return -1;
422 }
423 vp->v_data = ndep;
424 return 0;
425 }
426