fs/fdos/subdir.c

   1 /*
   2  * (C) Copyright 2002
   3  * Stäubli Faverges - <www.staubli.com>
   4  * Pierre AUBERT  p.aubert@staubli.com
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 #include <common.h>
  26 #include <config.h>
  27 #include <malloc.h>
  28
  29 #if (CONFIG_COMMANDS & CFG_CMD_FDOS)
  30
  31 #include "dos.h"
  32 #include "fdos.h"
  33
  34 static int cache_sect;
  35 static unsigned char cache [SZ_STD_SECTOR];
  36
  37
  38 #define min(x,y) ((x)<(y)?(x):(y))
  39
  40 static int descend (Slot_t *parent,
  41              Fs_t *fs,
  42                     char *path);
  43
  44 /*-----------------------------------------------------------------------------
  45  * init_subdir --
  46  *-----------------------------------------------------------------------------
  47  */
  48 void init_subdir (void)
  49 {
  50     cache_sect = -1;
  51 }
  52 /*-----------------------------------------------------------------------------
  53  * basename --
  54  *-----------------------------------------------------------------------------
  55  */
  56 char *basename (char *name)
  57 {
  58     register char *cptr;
  59
  60     if (!name || !*name) {
  61         return ("");
  62     }
  63
  64     for (cptr= name; *cptr++; );
  65     while (--cptr >= name) {
  66         if (*cptr == '/')    {
  67             return (cptr + 1);
  68         }
  69     }
  70     return(name);
  71 }
  72 /*-----------------------------------------------------------------------------
  73  * root_map --
  74  *-----------------------------------------------------------------------------
  75  */
  76 static int root_map (Fs_t *fs, Slot_t *file, int where, int *len)
  77 {
  78     *len = min (*len, fs -> dir_len * SZ_STD_SECTOR - where);
  79     if (*len < 0 ) {
  80         *len = 0;
  81         return (-1);
  82     }
  83     return fs -> dir_start * SZ_STD_SECTOR + where;
  84 }
  85 /*-----------------------------------------------------------------------------
  86  * normal_map --
  87  *-----------------------------------------------------------------------------
  88  */
  89 static int normal_map (Fs_t *fs, Slot_t *file, int where, int *len)
  90 {
  91     int offset;
  92     int NrClu;
  93     unsigned short RelCluNr;
  94     unsigned short CurCluNr;
  95     unsigned short NewCluNr;
  96     unsigned short AbsCluNr;
  97     int clus_size;
  98
  99     clus_size = fs -> cluster_size * SZ_STD_SECTOR;
 100     offset = where % clus_size;
 101
 102     *len = min (*len, file -> FileSize - where);
 103
 104     if (*len < 0 ) {
 105         *len = 0;
 106         return (0);
 107     }
 108
 109     if (file -> FirstAbsCluNr < 2){
 110         *len = 0;
 111         return (0);
 112     }
 113
 114     RelCluNr = where / clus_size;
 115
 116     if (RelCluNr >= file -> PreviousRelCluNr){
 117         CurCluNr = file -> PreviousRelCluNr;
 118         AbsCluNr = file -> PreviousAbsCluNr;
 119     } else {
 120         CurCluNr = 0;
 121         AbsCluNr = file -> FirstAbsCluNr;
 122     }
 123
 124
 125     NrClu = (offset + *len - 1) / clus_size;
 126     while (CurCluNr <= RelCluNr + NrClu) {
 127         if (CurCluNr == RelCluNr){
 128             /* we have reached the beginning of our zone. Save
 129              * coordinates */
 130             file -> PreviousRelCluNr = RelCluNr;
 131             file -> PreviousAbsCluNr = AbsCluNr;
 132         }
 133         NewCluNr = fat_decode (fs, AbsCluNr);
 134         if (NewCluNr == 1 || NewCluNr == 0) {
 135             PRINTF("Fat problem while decoding %d %x\n",
 136                     AbsCluNr, NewCluNr);
 137             return (-1);
 138         }
 139         if (CurCluNr == RelCluNr + NrClu) {
 140             break;
 141         }
 142
 143         if (CurCluNr < RelCluNr && NewCluNr == FAT12_END) {
 144             *len = 0;
 145             return 0;
 146         }
 147
 148         if (CurCluNr >= RelCluNr && NewCluNr != AbsCluNr + 1)
 149             break;
 150         CurCluNr++;
 151         AbsCluNr = NewCluNr;
 152     }
 153
 154     *len = min (*len, (1 + CurCluNr - RelCluNr) * clus_size - offset);
 155
 156     return (((file -> PreviousAbsCluNr - 2) * fs -> cluster_size +
 157              fs -> dir_start + fs -> dir_len) *
 158             SZ_STD_SECTOR + offset);
 159 }
 160 /*-----------------------------------------------------------------------------
 161  * open_subdir -- open the subdir containing the file
 162  *-----------------------------------------------------------------------------
 163  */
 164 int open_subdir (File_t *desc)
 165 {
 166     char *pathname;
 167     char *tmp, *s, *path;
 168     char terminator;
 169
 170     if ((pathname = (char *)malloc (MAX_PATH)) == NULL) {
 171         return (-1);
 172     }
 173
 174     strcpy (pathname, desc -> name);
 175
 176     /* Suppress file name                                                    */
 177     tmp = basename (pathname);
 178     *tmp = '\0';
 179
 180     /* root directory  init                                                  */
 181     desc -> subdir.FirstAbsCluNr = 0;
 182     desc -> subdir.FileSize = -1;
 183     desc -> subdir.map = root_map;
 184     desc -> subdir.dir.attr = ATTR_DIRECTORY;
 185
 186     tmp = pathname;
 187     for (s = tmp; ; ++s) {
 188         if (*s == '/' || *s == '\0') {
 189             path = tmp;
 190             terminator = *s;
 191             *s = '\0';
 192             if (s != tmp && strcmp (path,".")) {
 193                 if (descend (&desc -> subdir, desc -> fs, path) < 0) {
 194                     free (pathname);
 195                     return (-1);
 196                 }
 197             }
 198             if (terminator == 0) {
 199                 break;
 200             }
 201             tmp = s + 1;
 202         }
 203     }
 204     free (pathname);
 205     return (0);
 206 }
 207 /*-----------------------------------------------------------------------------
 208  * descend --
 209  *-----------------------------------------------------------------------------
 210  */
 211 static int descend (Slot_t *parent,
 212              Fs_t *fs,
 213              char *path)
 214 {
 215     int entry;
 216     Slot_t SubDir;
 217
 218     if(path[0] == '\0' || strcmp (path, ".") == 0) {
 219         return (0);
 220     }
 221
 222
 223     entry = 0;
 224     if (vfat_lookup (parent,
 225                      fs,
 226                      &(SubDir.dir),
 227                      &entry,
 228                      0,
 229                      path,
 230                      ACCEPT_DIR | SINGLE | DO_OPEN,
 231                      0,
 232                      &SubDir) == 0) {
 233         *parent = SubDir;
 234         return (0);
 235     }
 236
 237     if (strcmp(path, "..") == 0) {
 238         parent -> FileSize = -1;
 239         parent -> FirstAbsCluNr = 0;
 240         parent -> map = root_map;
 241         return (0);
 242     }
 243     return (-1);
 244 }
 245 /*-----------------------------------------------------------------------------
 246  * open_file --
 247  *-----------------------------------------------------------------------------
 248  */
 249 int open_file (Slot_t *file, Directory_t *dir)
 250 {
 251     int first;
 252     unsigned long size;
 253
 254     first = __le16_to_cpu (dir -> start);
 255
 256     if(first == 0 &&
 257        (dir -> attr & ATTR_DIRECTORY) != 0) {
 258         file -> FirstAbsCluNr = 0;
 259         file -> FileSize = -1;
 260         file -> map = root_map;
 261         return (0);
 262     }
 263
 264     if ((dir -> attr & ATTR_DIRECTORY) != 0) {
 265         size = (1UL << 31) - 1;
 266     }
 267     else {
 268         size = __le32_to_cpu (dir -> size);
 269     }
 270
 271     file -> map = normal_map;
 272     file -> FirstAbsCluNr = first;
 273     file -> PreviousRelCluNr = 0xffff;
 274     file -> FileSize = size;
 275     return (0);
 276 }
 277 /*-----------------------------------------------------------------------------
 278  * read_file --
 279  *-----------------------------------------------------------------------------
 280  */
 281 int read_file (Fs_t *fs,
 282                Slot_t *file,
 283                char *buf,
 284                int where,
 285                int len)
 286 {
 287     int pos;
 288     int read, nb, sect, offset;
 289
 290     pos = file -> map (fs, file, where, &len);
 291     if  (pos < 0) {
 292         return -1;
 293     }
 294     if (len == 0) {
 295         return (0);
 296     }
 297
 298     /* Compute sector number                                                 */
 299     sect = pos / SZ_STD_SECTOR;
 300     offset = pos % SZ_STD_SECTOR;
 301     read = 0;
 302
 303     if (offset) {
 304         /* Read doesn't start at the sector beginning. We need to use our    */
 305         /* cache                                                             */
 306         if (sect != cache_sect) {
 307             if (dev_read (cache, sect, 1) < 0) {
 308                 return (-1);
 309             }
 310             cache_sect = sect;
 311         }
 312         nb = min (len, SZ_STD_SECTOR - offset);
 313
 314         memcpy (buf, cache + offset, nb);
 315         read += nb;
 316         len -= nb;
 317         sect += 1;
 318     }
 319
 320     if (len > SZ_STD_SECTOR) {
 321         nb = (len - 1) / SZ_STD_SECTOR;
 322         if (dev_read (buf + read, sect, nb) < 0) {
 323             return ((read) ? read : -1);
 324         }
 325         /* update sector position                                            */
 326         sect += nb;
 327
 328         /* Update byte position                                              */
 329         nb *= SZ_STD_SECTOR;
 330         read += nb;
 331         len -= nb;
 332     }
 333
 334     if (len) {
 335         if (sect != cache_sect) {
 336             if (dev_read (cache, sect, 1) < 0) {
 337                 return ((read) ? read : -1);
 338                 cache_sect = -1;
 339             }
 340             cache_sect = sect;
 341         }
 342
 343         memcpy (buf + read, cache, len);
 344         read += len;
 345     }
 346     return (read);
 347 }
 348 #endif