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 __FBSDID("$FreeBSD: stable/12/usr.sbin/makefs/msdos/msdosfs_vfsops.c 352081 2019-09-09 17:34:18Z emaste $");
53
54 #include <sys/param.h>
55 #include <sys/mount.h>
56
57 #include <errno.h>
58 #include <stdio.h>
59 #include <string.h>
60 #include <stdlib.h>
61 #include <util.h>
62
63 #include <fs/msdosfs/bootsect.h>
64 #include <fs/msdosfs/bpb.h>
65
66 #include <mkfs_msdos.h>
67
68 #include "makefs.h"
69 #include "msdos.h"
70
71 #include "ffs/buf.h"
72
73 #include "msdos/denode.h"
74 #include "msdos/direntry.h"
75 #include "msdos/fat.h"
76 #include "msdos/msdosfsmount.h"
77
78 struct msdosfsmount *
msdosfs_mount(struct vnode * devvp)79 msdosfs_mount(struct vnode *devvp)
80 {
81 struct msdosfsmount *pmp = NULL;
82 struct buf *bp;
83 union bootsector *bsp;
84 struct byte_bpb33 *b33;
85 struct byte_bpb50 *b50;
86 struct byte_bpb710 *b710;
87 uint8_t SecPerClust;
88 int ronly = 0, error;
89 int bsize;
90 unsigned secsize = 512;
91
92 MSDOSFS_DPRINTF(("%s(bread 0)\n", __func__));
93 if ((error = bread(devvp, 0, secsize, 0, &bp)) != 0)
94 goto error_exit;
95
96 bsp = (union bootsector *)bp->b_data;
97 b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
98 b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
99 b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
100
101 if (bsp->bs50.bsBootSectSig0 != BOOTSIG0 ||
102 bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
103 MSDOSFS_DPRINTF(("bootsig0 %d bootsig1 %d\n",
104 bsp->bs50.bsBootSectSig0,
105 bsp->bs50.bsBootSectSig1));
106 error = EINVAL;
107 goto error_exit;
108 }
109 bsize = 0;
110
111 pmp = ecalloc(1, sizeof(*pmp));
112 /*
113 * Compute several useful quantities from the bpb in the
114 * bootsector. Copy in the dos 5 variant of the bpb then fix up
115 * the fields that are different between dos 5 and dos 3.3.
116 */
117 SecPerClust = b50->bpbSecPerClust;
118 pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
119 pmp->pm_ResSectors = getushort(b50->bpbResSectors);
120 pmp->pm_FATs = b50->bpbFATs;
121 pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
122 pmp->pm_Sectors = getushort(b50->bpbSectors);
123 pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
124 pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
125 pmp->pm_Heads = getushort(b50->bpbHeads);
126 pmp->pm_Media = b50->bpbMedia;
127
128 MSDOSFS_DPRINTF(("%s(BytesPerSec=%u, ResSectors=%u, FATs=%d, "
129 "RootDirEnts=%u, Sectors=%u, FATsecs=%lu, SecPerTrack=%u, "
130 "Heads=%u, Media=%u)\n",
131 __func__, pmp->pm_BytesPerSec, pmp->pm_ResSectors,
132 pmp->pm_FATs, pmp->pm_RootDirEnts, pmp->pm_Sectors,
133 pmp->pm_FATsecs, pmp->pm_SecPerTrack, pmp->pm_Heads,
134 pmp->pm_Media));
135
136 /* XXX - We should probably check more values here */
137 if (!pmp->pm_BytesPerSec || !SecPerClust
138 || pmp->pm_SecPerTrack > 63) {
139 MSDOSFS_DPRINTF(("bytespersec %d secperclust %d "
140 "secpertrack %d\n", pmp->pm_BytesPerSec,
141 SecPerClust, pmp->pm_SecPerTrack));
142 error = EINVAL;
143 goto error_exit;
144 }
145
146 if (pmp->pm_Sectors == 0) {
147 pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
148 pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
149 } else {
150 pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
151 pmp->pm_HugeSectors = pmp->pm_Sectors;
152 }
153
154 pmp->pm_flags = 0;
155 if (pmp->pm_RootDirEnts == 0) {
156 unsigned short vers = getushort(b710->bpbFSVers);
157 /*
158 * Some say that bsBootSectSig[23] must be zero, but
159 * Windows does not require this and some digital cameras
160 * do not set these to zero. Therefore, do not insist.
161 */
162 if (pmp->pm_Sectors || pmp->pm_FATsecs || vers) {
163 MSDOSFS_DPRINTF(("sectors %d fatsecs %lu vers %d\n",
164 pmp->pm_Sectors, pmp->pm_FATsecs, vers));
165 error = EINVAL;
166 goto error_exit;
167 }
168 pmp->pm_fatmask = FAT32_MASK;
169 pmp->pm_fatmult = 4;
170 pmp->pm_fatdiv = 1;
171 pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
172
173 /* mirrorring is enabled if the FATMIRROR bit is not set */
174 if ((getushort(b710->bpbExtFlags) & FATMIRROR) == 0)
175 pmp->pm_flags |= MSDOSFS_FATMIRROR;
176 else
177 pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
178 } else
179 pmp->pm_flags |= MSDOSFS_FATMIRROR;
180
181 /* Check that fs has nonzero FAT size */
182 if (pmp->pm_FATsecs == 0) {
183 MSDOSFS_DPRINTF(("FATsecs is 0\n"));
184 error = EINVAL;
185 goto error_exit;
186 }
187
188 pmp->pm_fatblk = pmp->pm_ResSectors;
189 if (FAT32(pmp)) {
190 pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
191 pmp->pm_firstcluster = pmp->pm_fatblk
192 + (pmp->pm_FATs * pmp->pm_FATsecs);
193 pmp->pm_fsinfo = getushort(b710->bpbFSInfo);
194 } else {
195 pmp->pm_rootdirblk = pmp->pm_fatblk +
196 (pmp->pm_FATs * pmp->pm_FATsecs);
197 pmp->pm_rootdirsize = (pmp->pm_RootDirEnts * sizeof(struct direntry)
198 + pmp->pm_BytesPerSec - 1)
199 / pmp->pm_BytesPerSec;/* in sectors */
200 pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
201 }
202
203 pmp->pm_maxcluster = ((pmp->pm_HugeSectors - pmp->pm_firstcluster) /
204 SecPerClust) + 1;
205 pmp->pm_fatsize = pmp->pm_FATsecs * pmp->pm_BytesPerSec;
206
207 if (pmp->pm_fatmask == 0) {
208 if (pmp->pm_maxcluster
209 <= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
210 /*
211 * This will usually be a floppy disk. This size makes
212 * sure that one FAT entry will not be split across
213 * multiple blocks.
214 */
215 pmp->pm_fatmask = FAT12_MASK;
216 pmp->pm_fatmult = 3;
217 pmp->pm_fatdiv = 2;
218 } else {
219 pmp->pm_fatmask = FAT16_MASK;
220 pmp->pm_fatmult = 2;
221 pmp->pm_fatdiv = 1;
222 }
223 }
224 if (FAT12(pmp))
225 pmp->pm_fatblocksize = 3 * pmp->pm_BytesPerSec;
226 else
227 pmp->pm_fatblocksize = MAXBSIZE;
228
229 pmp->pm_fatblocksec = pmp->pm_fatblocksize / pmp->pm_BytesPerSec;
230 pmp->pm_bnshift = ffs(pmp->pm_BytesPerSec) - 1;
231
232 /*
233 * Compute mask and shift value for isolating cluster relative byte
234 * offsets and cluster numbers from a file offset.
235 */
236 pmp->pm_bpcluster = SecPerClust * pmp->pm_BytesPerSec;
237 pmp->pm_crbomask = pmp->pm_bpcluster - 1;
238 pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
239
240 MSDOSFS_DPRINTF(("%s(fatmask=%lu, fatmult=%u, fatdiv=%u, "
241 "fatblocksize=%lu, fatblocksec=%lu, bnshift=%lu, pbcluster=%lu, "
242 "crbomask=%lu, cnshift=%lu)\n",
243 __func__, (unsigned long)pmp->pm_fatmask, pmp->pm_fatmult,
244 pmp->pm_fatdiv, pmp->pm_fatblocksize, pmp->pm_fatblocksec,
245 pmp->pm_bnshift, pmp->pm_bpcluster, pmp->pm_crbomask,
246 pmp->pm_cnshift));
247 /*
248 * Check for valid cluster size
249 * must be a power of 2
250 */
251 if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
252 MSDOSFS_DPRINTF(("bpcluster %lu cnshift %lu\n",
253 pmp->pm_bpcluster, pmp->pm_cnshift));
254 error = EINVAL;
255 goto error_exit;
256 }
257
258 /*
259 * Release the bootsector buffer.
260 */
261 brelse(bp);
262 bp = NULL;
263
264 /*
265 * Check FSInfo.
266 */
267 if (pmp->pm_fsinfo) {
268 struct fsinfo *fp;
269
270 /*
271 * XXX If the fsinfo block is stored on media with
272 * 2KB or larger sectors, is the fsinfo structure
273 * padded at the end or in the middle?
274 */
275 if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
276 0, &bp)) != 0)
277 goto error_exit;
278 fp = (struct fsinfo *)bp->b_data;
279 if (!memcmp(fp->fsisig1, "RRaA", 4)
280 && !memcmp(fp->fsisig2, "rrAa", 4)
281 && !memcmp(fp->fsisig3, "\0\0\125\252", 4))
282 pmp->pm_nxtfree = getulong(fp->fsinxtfree);
283 else
284 pmp->pm_fsinfo = 0;
285 brelse(bp);
286 bp = NULL;
287 }
288
289 /*
290 * Check and validate (or perhaps invalidate?) the fsinfo structure?
291 * XXX
292 */
293 if (pmp->pm_fsinfo) {
294 if ((pmp->pm_nxtfree == 0xffffffffUL) ||
295 (pmp->pm_nxtfree > pmp->pm_maxcluster))
296 pmp->pm_fsinfo = 0;
297 }
298
299 /*
300 * Allocate memory for the bitmap of allocated clusters, and then
301 * fill it in.
302 */
303 pmp->pm_inusemap = ecalloc(sizeof(*pmp->pm_inusemap),
304 ((pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS));
305 /*
306 * fillinusemap() needs pm_devvp.
307 */
308 pmp->pm_dev = 0;
309 pmp->pm_devvp = devvp;
310
311 /*
312 * Have the inuse map filled in.
313 */
314 if ((error = fillinusemap(pmp)) != 0) {
315 MSDOSFS_DPRINTF(("fillinusemap %d\n", error));
316 goto error_exit;
317 }
318
319 /*
320 * Finish up.
321 */
322 if (ronly)
323 pmp->pm_flags |= MSDOSFSMNT_RONLY;
324 else
325 pmp->pm_fmod = 1;
326
327 /*
328 * If we ever do quotas for DOS filesystems this would be a place
329 * to fill in the info in the msdosfsmount structure. You dolt,
330 * quotas on dos filesystems make no sense because files have no
331 * owners on dos filesystems. of course there is some empty space
332 * in the directory entry where we could put uid's and gid's.
333 */
334
335 return pmp;
336
337 error_exit:
338 if (bp)
339 brelse(bp);
340 if (pmp) {
341 if (pmp->pm_inusemap)
342 free(pmp->pm_inusemap);
343 free(pmp);
344 }
345 errno = error;
346 return NULL;
347 }
348
349 int
msdosfs_root(struct msdosfsmount * pmp,struct vnode * vp)350 msdosfs_root(struct msdosfsmount *pmp, struct vnode *vp) {
351 struct denode *ndep;
352 int error;
353
354 *vp = *pmp->pm_devvp;
355 if ((error = deget(pmp, MSDOSFSROOT, MSDOSFSROOT_OFS, &ndep)) != 0) {
356 errno = error;
357 return -1;
358 }
359 vp->v_data = ndep;
360 return 0;
361 }
362
363 /*
364 * If we have an FSInfo block, update it.
365 */
366 int
msdosfs_fsiflush(struct msdosfsmount * pmp)367 msdosfs_fsiflush(struct msdosfsmount *pmp)
368 {
369 struct fsinfo *fp;
370 struct buf *bp;
371 int error;
372
373 if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
374 error = 0;
375 goto out;
376 }
377 error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
378 NOCRED, &bp);
379 if (error != 0) {
380 brelse(bp);
381 goto out;
382 }
383 fp = (struct fsinfo *)bp->b_data;
384 putulong(fp->fsinfree, pmp->pm_freeclustercount);
385 putulong(fp->fsinxtfree, pmp->pm_nxtfree);
386 pmp->pm_flags &= ~MSDOSFS_FSIMOD;
387 error = bwrite(bp);
388
389 out:
390 return (error);
391 }
392