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 */ 69int 70createde(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 */ 267int 268readep(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 */ 294int 295readde(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 */ 304int 305uniqdosname(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