1 /* $OpenBSD: msdosfs_lookup.c,v 1.4 2021/10/06 00:40:41 deraadt Exp $ */
2 /* $NetBSD: msdosfs_lookup.c,v 1.35 2016/01/30 09:59:27 mlelstv Exp $ */
3
4 /*-
5 * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
6 * Copyright (C) 1994, 1995, 1997 TooLs GmbH.
7 * All rights reserved.
8 * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by TooLs GmbH.
21 * 4. The name of TooLs GmbH may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35 /*
36 * Written by Paul Popelka (paulp@uts.amdahl.com)
37 *
38 * You can do anything you want with this software, just don't say you wrote
39 * it, and don't remove this notice.
40 *
41 * This software is provided "as is".
42 *
43 * The author supplies this software to be publicly redistributed on the
44 * understanding that the author is not responsible for the correct
45 * functioning of this software in any circumstances and is not liable for
46 * any damages caused by this software.
47 *
48 * October 1992
49 */
50
51
52 #include "ffs/buf.h"
53
54 #include <msdosfs/bpb.h>
55 #include "msdos/direntry.h"
56 #include "msdos/denode.h"
57 #include "msdos/msdosfsmount.h"
58 #include "msdos/fat.h"
59
60
61
62 /*
63 * dep - directory entry to copy into the directory
64 * ddep - directory to add to
65 * depp - return the address of the denode for the created directory entry
66 * if depp != 0
67 * cnp - componentname needed for Win95 long filenames
68 */
69 int
createde(struct denode * dep,struct denode * ddep,struct denode ** depp,struct componentname * cnp)70 createde(struct denode *dep, struct denode *ddep, struct denode **depp, struct componentname *cnp)
71 {
72 int error, rberror;
73 u_long dirclust, clusoffset;
74 u_long fndoffset, havecnt = 0, wcnt = 1, i;
75 struct direntry *ndep;
76 struct msdosfsmount *pmp = ddep->de_pmp;
77 struct mkfsbuf *bp;
78 daddr_t bn;
79 int blsize;
80 #define async 0
81
82 #ifdef MSDOSFS_DEBUG
83 printf("createde(dep %p, ddep %p, depp %p, cnp %p)\n",
84 dep, ddep, depp, cnp);
85 #endif
86
87 /*
88 * If no space left in the directory then allocate another cluster
89 * and chain it onto the end of the file. There is one exception
90 * to this. That is, if the root directory has no more space it
91 * can NOT be expanded. extendfile() checks for and fails attempts
92 * to extend the root directory. We just return an error in that
93 * case.
94 */
95 if (ddep->de_fndoffset >= ddep->de_FileSize) {
96 u_long needlen = ddep->de_fndoffset + sizeof(struct direntry)
97 - ddep->de_FileSize;
98 dirclust = de_clcount(pmp, needlen);
99 if ((error = extendfile(ddep, dirclust, 0, 0, DE_CLEAR)) != 0) {
100 (void)detrunc(ddep, ddep->de_FileSize, 0);
101 goto err_norollback;
102 }
103
104 /*
105 * Update the size of the directory
106 */
107 ddep->de_FileSize += de_cn2off(pmp, dirclust);
108 }
109
110 /*
111 * We just read in the cluster with space. Copy the new directory
112 * entry in. Then write it to disk. NOTE: DOS directories
113 * do not get smaller as clusters are emptied.
114 */
115 error = pcbmap(ddep, de_cluster(pmp, ddep->de_fndoffset),
116 &bn, &dirclust, &blsize);
117 if (error)
118 goto err_norollback;
119 clusoffset = ddep->de_fndoffset;
120 if (dirclust != MSDOSFSROOT)
121 clusoffset &= pmp->pm_crbomask;
122 if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
123 B_MODIFY, &bp)) != 0) {
124 goto err_norollback;
125 }
126 ndep = bptoep(pmp, bp, clusoffset);
127
128 DE_EXTERNALIZE(ndep, dep);
129
130 /*
131 * Now write the Win95 long name
132 */
133 if (ddep->de_fndcnt > 0) {
134 u_int8_t chksum = winChksum(ndep->deName);
135 u_char *un = cnp->cn_nameptr;
136 int unlen = cnp->cn_namelen;
137 u_long xhavecnt;
138
139 fndoffset = ddep->de_fndoffset;
140 xhavecnt = ddep->de_fndcnt + 1;
141
142 for(; wcnt < xhavecnt; wcnt++) {
143 if ((fndoffset & pmp->pm_crbomask) == 0) {
144 /* we should never get here if ddep is root
145 * directory */
146
147 if (async)
148 (void) bdwrite(bp);
149 else if ((error = bwrite(bp)) != 0)
150 goto rollback;
151
152 fndoffset -= sizeof(struct direntry);
153 error = pcbmap(ddep,
154 de_cluster(pmp, fndoffset),
155 &bn, 0, &blsize);
156 if (error)
157 goto rollback;
158
159 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
160 blsize, B_MODIFY, &bp);
161 if (error) {
162 goto rollback;
163 }
164 ndep = bptoep(pmp, bp,
165 fndoffset & pmp->pm_crbomask);
166 } else {
167 ndep--;
168 fndoffset -= sizeof(struct direntry);
169 }
170 if (!unix2winfn(un, unlen, (struct winentry *)ndep,
171 wcnt, chksum))
172 break;
173 }
174 }
175
176 if (async)
177 bdwrite(bp);
178 else if ((error = bwrite(bp)) != 0)
179 goto rollback;
180
181 /*
182 * If they want us to return with the denode gotten.
183 */
184 if (depp) {
185 u_long diroffset = clusoffset;
186
187 if (dep->de_Attributes & ATTR_DIRECTORY) {
188 dirclust = dep->de_StartCluster;
189 if (FAT32(pmp) && dirclust == pmp->pm_rootdirblk)
190 dirclust = MSDOSFSROOT;
191 if (dirclust == MSDOSFSROOT)
192 diroffset = MSDOSFSROOT_OFS;
193 else
194 diroffset = 0;
195 }
196 error = deget(pmp, dirclust, diroffset, depp);
197 return error;
198 }
199
200 return 0;
201
202 rollback:
203 /*
204 * Mark all slots modified so far as deleted. Note that we
205 * can't just call removede(), since directory is not in
206 * consistent state.
207 */
208 fndoffset = ddep->de_fndoffset;
209 rberror = pcbmap(ddep, de_cluster(pmp, fndoffset),
210 &bn, NULL, &blsize);
211 if (rberror)
212 goto err_norollback;
213 if ((rberror = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
214 B_MODIFY, &bp)) != 0) {
215 goto err_norollback;
216 }
217 ndep = bptoep(pmp, bp, clusoffset);
218
219 havecnt = ddep->de_fndcnt + 1;
220 for(i = wcnt; i <= havecnt; i++) {
221 /* mark entry as deleted */
222 ndep->deName[0] = SLOT_DELETED;
223
224 if ((fndoffset & pmp->pm_crbomask) == 0) {
225 /* we should never get here if ddep is root
226 * directory */
227
228 if (async)
229 bdwrite(bp);
230 else if ((rberror = bwrite(bp)) != 0)
231 goto err_norollback;
232
233 fndoffset -= sizeof(struct direntry);
234 rberror = pcbmap(ddep,
235 de_cluster(pmp, fndoffset),
236 &bn, 0, &blsize);
237 if (rberror)
238 goto err_norollback;
239
240 rberror = bread(pmp->pm_devvp, de_bn2kb(pmp, bn),
241 blsize, B_MODIFY, &bp);
242 if (rberror) {
243 goto err_norollback;
244 }
245 ndep = bptoep(pmp, bp, fndoffset);
246 } else {
247 ndep--;
248 fndoffset -= sizeof(struct direntry);
249 }
250 }
251
252 /* ignore any further error */
253 if (async)
254 (void) bdwrite(bp);
255 else
256 (void) bwrite(bp);
257
258 err_norollback:
259 return error;
260 }
261
262 /*
263 * Read in the disk block containing the directory entry (dirclu, dirofs)
264 * and return the address of the buf header, and the address of the
265 * directory entry within the block.
266 */
267 int
readep(struct msdosfsmount * pmp,u_long dirclust,u_long diroffset,struct mkfsbuf ** bpp,struct direntry ** epp)268 readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, struct mkfsbuf **bpp, struct direntry **epp)
269 {
270 int error;
271 daddr_t bn;
272 int blsize;
273
274 blsize = pmp->pm_bpcluster;
275 if (dirclust == MSDOSFSROOT
276 && de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
277 blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
278 bn = detobn(pmp, dirclust, diroffset);
279 if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
280 0, bpp)) != 0) {
281 *bpp = NULL;
282 return (error);
283 }
284 if (epp)
285 *epp = bptoep(pmp, *bpp, diroffset);
286 return (0);
287 }
288
289 /*
290 * Read in the disk block containing the directory entry dep came from and
291 * return the address of the buf header, and the address of the directory
292 * entry within the block.
293 */
294 int
readde(struct denode * dep,struct mkfsbuf ** bpp,struct direntry ** epp)295 readde(struct denode *dep, struct mkfsbuf **bpp, struct direntry **epp)
296 {
297 return (readep(dep->de_pmp, dep->de_dirclust, dep->de_diroffset,
298 bpp, epp));
299 }
300
301 /*
302 * Create a unique DOS name in dvp
303 */
304 int
uniqdosname(struct denode * dep,struct componentname * cnp,u_char * cp)305 uniqdosname(struct denode *dep, struct componentname *cnp, u_char *cp)
306 {
307 struct msdosfsmount *pmp = dep->de_pmp;
308 struct direntry *dentp;
309 int gen;
310 int blsize;
311 u_long cn;
312 daddr_t bn;
313 struct mkfsbuf *bp;
314 int error;
315
316 for (gen = 1;; gen++) {
317 /*
318 * Generate DOS name with generation number
319 */
320 if (!unix2dosfn(cnp->cn_nameptr, cp, cnp->cn_namelen, gen))
321 return gen == 1 ? EINVAL : EEXIST;
322
323 /*
324 * Now look for a dir entry with this exact name
325 */
326 for (cn = error = 0; !error; cn++) {
327 if ((error = pcbmap(dep, cn, &bn, 0, &blsize)) != 0) {
328 if (error == E2BIG) /* EOF reached and not found */
329 return 0;
330 return error;
331 }
332 error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize,
333 0, &bp);
334 if (error) {
335 return error;
336 }
337 for (dentp = (struct direntry *)bp->b_data;
338 (char *)dentp < (char *)bp->b_data + blsize;
339 dentp++) {
340 if (dentp->deName[0] == SLOT_EMPTY) {
341 /*
342 * Last used entry and not found
343 */
344 brelse(bp, 0);
345 return 0;
346 }
347 /*
348 * Ignore volume labels and Win95 entries
349 */
350 if (dentp->deAttributes & ATTR_VOLUME)
351 continue;
352 if (!memcmp(dentp->deName, cp, 11)) {
353 error = EEXIST;
354 break;
355 }
356 }
357 brelse(bp, 0);
358 }
359 }
360 }
361