1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
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
50 #include <sys/cdefs.h>
51 /* $NetBSD: msdosfs_vfsops.c,v 1.10 2016/01/30 09:59:27 mlelstv Exp $ */
52 #include <sys/param.h>
53 #include <sys/mount.h>
54
55 #include <errno.h>
56 #include <stdbool.h>
57 #include <stdio.h>
58 #include <string.h>
59 #include <stdlib.h>
60 #include <util.h>
61
62 #include "ffs/buf.h"
63 #include <fs/msdosfs/bootsect.h>
64 #include <fs/msdosfs/bpb.h>
65 #include "msdos/direntry.h"
66 #include <fs/msdosfs/denode.h>
67 #include <fs/msdosfs/fat.h>
68 #include <fs/msdosfs/msdosfsmount.h>
69
70 #include <mkfs_msdos.h>
71
72 #include "makefs.h"
73 #include "msdos.h"
74
75
76
77 struct msdosfsmount *
msdosfs_mount(struct vnode * devvp)78 msdosfs_mount(struct vnode *devvp)
79 {
80 struct msdosfsmount *pmp = NULL;
81 struct buf *bp;
82 union bootsector *bsp;
83 struct byte_bpb33 *b33;
84 struct byte_bpb50 *b50;
85 struct byte_bpb710 *b710;
86 uint8_t SecPerClust;
87 int ronly = 0, error;
88 int bsize;
89 unsigned secsize = 512;
90
91 MSDOSFS_DPRINTF(("%s(bread 0)\n", __func__));
92 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0)
93 goto error_exit;
94
95 bsp = (union bootsector *)bp->b_data;
96 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
97 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
98 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
99
100 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 ||
101 bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
102 MSDOSFS_DPRINTF(("bootsig0 %d bootsig1 %d\n",
103 bsp->bs50.bsBootSectSig0,
104 bsp->bs50.bsBootSectSig1));
105 error = EINVAL;
106 goto error_exit;
107 }
108 bsize = 0;
109
110 pmp = ecalloc(1, sizeof(*pmp));
111 /*
112 * Compute several useful quantities from the bpb in the
113 * bootsector. Copy in the dos 5 variant of the bpb then fix up
114 * the fields that are different between dos 5 and dos 3.3.
115 */
116 SecPerClust = b50->bpbSecPerClust;
117 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
118 pmp->pm_ResSectors = getushort(b50->bpbResSectors);
119 pmp->pm_FATs = b50->bpbFATs;
120 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
121 pmp->pm_Sectors = getushort(b50->bpbSectors);
122 pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
123 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
124 pmp->pm_Heads = getushort(b50->bpbHeads);
125 pmp->pm_Media = b50->bpbMedia;
126
127 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, "
128 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, "
129 "Heads=%u, Media=%u)\n",
130 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors,
131 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors,
132 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads,
133 pmp->pm_Media));
134
135 /* XXX - We should probably check more values here */
136 if (!pmp->pm_BytesPerSec || !SecPerClust
137 || pmp->pm_SecPerTrack > 63) {
138 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d "
139 "secpertrack %d\n", pmp->pm_BytesPerSec,
140 SecPerClust, pmp->pm_SecPerTrack));
141 error = EINVAL;
142 goto error_exit;
143 }
144
145 if (pmp->pm_Sectors == 0) {
146 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
147 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
148 } else {
149 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
150 pmp->pm_HugeSectors = pmp->pm_Sectors;
151 }
152
153 pmp->pm_flags = 0;
154 if (pmp->pm_RootDirEnts == 0) {
155 unsigned short vers = getushort(b710->bpbFSVers);
156 /*
157 * Some say that bsBootSectSig[23] must be zero, but
158 * Windows does not require this and some digital cameras
159 * do not set these to zero. Therefore, do not insist.
160 */
161 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
162 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n",
163 pmp->pm_Sectors, pmp->pm_FATsecs, vers));
164 error = EINVAL;
165 goto error_exit;
166 }
167 pmp->pm_fatmask = FAT32_MASK;
168 pmp->pm_fatmult = 4;
169 pmp->pm_fatdiv = 1;
170 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
171
172 /* mirrorring is enabled if the FATMIRROR bit is not set */
173 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
174 pmp->pm_flags |= MSDOSFS_FATMIRROR;
175 else
176 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
177 } else
178 pmp->pm_flags |= MSDOSFS_FATMIRROR;
179
180 /* Check that fs has nonzero FAT size */
181 if (pmp->pm_FATsecs == 0) {
182 MSDOSFS_DPRINTF(("FATsecs is 0\n"));
183 error = EINVAL;
184 goto error_exit;
185 }
186
187 pmp->pm_fatblk = pmp->pm_ResSectors;
188 if (FAT32(pmp)) {
189 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
190 pmp->pm_firstcluster = pmp->pm_fatblk
191 + (pmp->pm_FATs * pmp->pm_FATsecs);
192 pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
193 } else {
194 pmp->pm_rootdirblk = pmp->pm_fatblk +
195 (pmp->pm_FATs * pmp->pm_FATsecs);
196 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
197 + pmp->pm_BytesPerSec - 1)
198 / pmp->pm_BytesPerSec;/* in sectors */
199 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
200 }
201
202 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) /
203 SecPerClust) + 1;
204 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
205
206 if (pmp->pm_fatmask == 0) {
207 if (pmp->pm_maxcluster
208 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
209 /*
210 * This will usually be a floppy disk. This size makes
211 * sure that one FAT entry will not be split across
212 * multiple blocks.
213 */
214 pmp->pm_fatmask = FAT12_MASK;
215 pmp->pm_fatmult = 3;
216 pmp->pm_fatdiv = 2;
217 } else {
218 pmp->pm_fatmask = FAT16_MASK;
219 pmp->pm_fatmult = 2;
220 pmp->pm_fatdiv = 1;
221 }
222 }
223 if (FAT12(pmp))
224 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
225 else
226 pmp->pm_fatblocksize = MAXBSIZE;
227
228 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
229 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
230
231 /*
232 * Compute mask and shift value for isolating cluster relative byte
233 * offsets and cluster numbers from a file offset.
234 */
235 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
236 pmp->pm_crbomask = pmp->pm_bpcluster - 1;
237 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
238
239 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, "
240 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, "
241 "crbomask=%lu, cnshift=%lu)\n",
242 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult,
243 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec,
244 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask,
245 pmp->pm_cnshift));
246 /*
247 * Check for valid cluster size
248 * must be a power of 2
249 */
250 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
251 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n",
252 pmp->pm_bpcluster, pmp->pm_cnshift));
253 error = EINVAL;
254 goto error_exit;
255 }
256
257 /*
258 * Release the bootsector buffer.
259 */
260 brelse(bp);
261 bp = NULL;
262
263 /*
264 * Check FSInfo.
265 */
266 if (pmp->pm_fsinfo) {
267 struct fsinfo *fp;
268
269 /*
270 * XXX If the fsinfo block is stored on media with
271 * 2KB or larger sectors, is the fsinfo structure
272 * padded at the end or in the middle?
273 */
274 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
275 0, &bp)) != 0)
276 goto error_exit;
277 fp = (struct fsinfo *)bp->b_data;
278 if (!memcmp(fp->fsisig1, "RRaA", 4)
279 && !memcmp(fp->fsisig2, "rrAa", 4)
280 && !memcmp(fp->fsisig3, "\0\0\125\252", 4))
281 pmp->pm_nxtfree = getulong(fp->fsinxtfree);
282 else
283 pmp->pm_fsinfo = 0;
284 brelse(bp);
285 bp = NULL;
286 }
287
288 /*
289 * Check and validate (or perhaps invalidate?) the fsinfo structure?
290 * XXX
291 */
292 if (pmp->pm_fsinfo) {
293 if ((pmp->pm_nxtfree == 0xffffffffUL) ||
294 (pmp->pm_nxtfree > pmp->pm_maxcluster))
295 pmp->pm_fsinfo = 0;
296 }
297
298 /*
299 * Allocate memory for the bitmap of allocated clusters, and then
300 * fill it in.
301 */
302 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap),
303 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS));
304 /*
305 * fillinusemap() needs pm_devvp.
306 */
307 pmp->pm_dev = 0;
308 pmp->pm_devvp = devvp;
309
310 /*
311 * Have the inuse map filled in.
312 */
313 if ((error = fillinusemap(pmp)) != 0) {
314 MSDOSFS_DPRINTF(("fillinusemap %d\n", error));
315 goto error_exit;
316 }
317
318 /*
319 * Finish up.
320 */
321 if (ronly)
322 pmp->pm_flags |= MSDOSFSMNT_RONLY;
323 else
324 pmp->pm_fmod = 1;
325
326 /*
327 * If we ever do quotas for DOS filesystems this would be a place
328 * to fill in the info in the msdosfsmount structure. You dolt,
329 * quotas on dos filesystems make no sense because files have no
330 * owners on dos filesystems. of course there is some empty space
331 * in the directory entry where we could put uid's and gid's.
332 */
333
334 return pmp;
335
336 error_exit:
337 if (bp)
338 brelse(bp);
339 if (pmp) {
340 if (pmp->pm_inusemap)
341 free(pmp->pm_inusemap);
342 free(pmp);
343 }
344 errno = error;
345 return NULL;
346 }
347
348 int
msdosfs_root(struct msdosfsmount * pmp,struct vnode * vp)349 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) {
350 struct denode *ndep;
351 int error;
352
353 *vp = *pmp->pm_devvp;
354 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, 0, &ndep)) != 0) {
355 errno = error;
356 return -1;
357 }
358 vp->v_data = ndep;
359 return 0;
360 }
361
362 /*
363 * If we have an FSInfo block, update it.
364 */
365 int
msdosfs_fsiflush(struct msdosfsmount * pmp)366 msdosfs_fsiflush(struct msdosfsmount *pmp)
367 {
368 struct fsinfo *fp;
369 struct buf *bp;
370 int error;
371
372 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
373 error = 0;
374 goto out;
375 }
376 error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
377 NOCRED, &bp);
378 if (error != 0) {
379 brelse(bp);
380 goto out;
381 }
382 fp = (struct fsinfo *)bp->b_data;
383 putulong(fp->fsinfree, pmp->pm_freeclustercount);
384 putulong(fp->fsinxtfree, pmp->pm_nxtfree);
385 pmp->pm_flags &= ~MSDOSFS_FSIMOD;
386 error = bwrite(bp);
387
388 out:
389 return (error);
390 }
391