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