package/firmware/fritz-tools/src/fritz_tffs_read.c

   1 /*
   2  * A tool for reading the TFFS partitions (a name-value storage usually
   3  * found in AVM Fritz!Box based devices).
   4  *
   5  * Copyright (c) 2015-2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
   6  *
   7  * Based on the TFFS 2.0 kernel driver from AVM:
   8  *     Copyright (c) 2004-2007 AVM GmbH <fritzbox_info@avm.de>
   9  * and the OpenWrt TFFS kernel driver:
  10  *     Copyright (c) 2013 John Crispin <blogic@openwrt.org>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include <stdbool.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <stdint.h>
  31 #include <string.h>
  32 #include <libgen.h>
  33 #include <getopt.h>
  34 #include <unistd.h>
  35 #include <sys/types.h>
  36 #include <sys/stat.h>
  37 #include <arpa/inet.h>
  38
  39 #define DEFAULT_TFFS_SIZE       (256 * 1024)
  40
  41 #define TFFS_ID_END             0xffff
  42 #define TFFS_ID_TABLE_NAME      0x01ff
  43
  44 static char *progname;
  45 static char *input_file;
  46 static unsigned long tffs_size = DEFAULT_TFFS_SIZE;
  47 static char *name_filter = NULL;
  48 static bool show_all = false;
  49 static bool print_all_key_names = false;
  50 static bool swap_bytes = false;
  51
  52 struct tffs_entry_header {
  53         uint16_t id;
  54         uint16_t len;
  55 };
  56
  57 struct tffs_entry {
  58         const struct tffs_entry_header *header;
  59         char *name;
  60         uint8_t *val;
  61 };
  62
  63 struct tffs_name_table_entry {
  64         const uint32_t *id;
  65         const char *val;
  66 };
  67
  68 struct tffs_key_name_table {
  69         uint32_t size;
  70         struct tffs_name_table_entry *entries;
  71 };
  72
  73 static inline uint16_t get_header_len(const struct tffs_entry_header *header)
  74 {
  75         if (swap_bytes)
  76                 return ntohs(header->len);
  77
  78         return header->len;
  79 }
  80
  81 static inline uint16_t get_header_id(const struct tffs_entry_header *header)
  82 {
  83         if (swap_bytes)
  84                 return ntohs(header->id);
  85
  86         return header->id;
  87 }
  88
  89 static inline uint16_t to_entry_header_id(uint32_t name_id)
  90 {
  91         if (swap_bytes)
  92                 return ntohl(name_id) & 0xffff;
  93
  94         return name_id & 0xffff;
  95 }
  96
  97 static inline uint32_t get_walk_size(uint32_t entry_len)
  98 {
  99         return (entry_len + 3) & ~0x03;
 100 }
 101
 102 static void print_entry_value(const struct tffs_entry *entry)
 103 {
 104         int i;
 105
 106         /* These are NOT NULL terminated. */
 107         for (i = 0; i < get_header_len(entry->header); i++)
 108                 fprintf(stdout, "%c", entry->val[i]);
 109 }
 110
 111 static void parse_entry(uint8_t *buffer, uint32_t pos,
 112                         struct tffs_entry *entry)
 113 {
 114         entry->header = (struct tffs_entry_header *) &buffer[pos];
 115         entry->val = &buffer[pos + sizeof(struct tffs_entry_header)];
 116 }
 117
 118 static int find_entry(uint8_t *buffer, uint16_t id, struct tffs_entry *entry)
 119 {
 120         uint32_t pos = 0;
 121
 122         do {
 123                 parse_entry(buffer, pos, entry);
 124
 125                 if (get_header_id(entry->header) == id)
 126                         return 1;
 127
 128                 pos += sizeof(struct tffs_entry_header);
 129                 pos += get_walk_size(get_header_len(entry->header));
 130         } while (pos < tffs_size && entry->header->id != TFFS_ID_END);
 131
 132         return 0;
 133 }
 134
 135 static void parse_key_names(struct tffs_entry *names_entry,
 136                             struct tffs_key_name_table *key_names)
 137 {
 138         uint32_t pos = 0, i = 0;
 139         struct tffs_name_table_entry *name_item;
 140
 141         key_names->entries = calloc(sizeof(*name_item), 1);
 142
 143         do {
 144                 name_item = &key_names->entries[i];
 145
 146                 name_item->id = (uint32_t *) &names_entry->val[pos];
 147                 pos += sizeof(*name_item->id);
 148                 name_item->val = (const char *) &names_entry->val[pos];
 149
 150                 /*
 151                  * There is no "length" field because the string values are
 152                  * simply NULL-terminated -> strlen() gives us the size.
 153                  */
 154                 pos += get_walk_size(strlen(name_item->val) + 1);
 155
 156                 ++i;
 157                 key_names->entries = realloc(key_names->entries,
 158                                                 sizeof(*name_item) * (i + 1));
 159         } while (pos < get_header_len(names_entry->header));
 160
 161         key_names->size = i;
 162 }
 163
 164 static void show_all_key_names(struct tffs_key_name_table *key_names)
 165 {
 166         int i;
 167
 168         for (i = 0; i < key_names->size; i++)
 169                 printf("%s\n", key_names->entries[i].val);
 170 }
 171
 172 static int show_all_key_value_pairs(uint8_t *buffer,
 173                                     struct tffs_key_name_table *key_names)
 174 {
 175         int i, has_value = 0;
 176         uint16_t id;
 177         struct tffs_entry tmp;
 178
 179         for (i = 0; i < key_names->size; i++) {
 180                 id = to_entry_header_id(*key_names->entries[i].id);
 181
 182                 if (find_entry(buffer, id, &tmp)) {
 183                         printf("%s=", key_names->entries[i].val);
 184                         print_entry_value(&tmp);
 185                         printf("\n");
 186                         has_value++;
 187                 }
 188         }
 189
 190         if (!has_value) {
 191                 fprintf(stderr, "ERROR: no values found!\n");
 192                 return EXIT_FAILURE;
 193         }
 194
 195         return EXIT_SUCCESS;
 196 }
 197
 198 static int show_matching_key_value(uint8_t *buffer,
 199                                    struct tffs_key_name_table *key_names)
 200 {
 201         int i;
 202         uint16_t id;
 203         struct tffs_entry tmp;
 204         const char *name;
 205
 206         for (i = 0; i < key_names->size; i++) {
 207                 name = key_names->entries[i].val;
 208
 209                 if (strncmp(name, name_filter, strlen(name)) == 0) {
 210                         id = to_entry_header_id(*key_names->entries[i].id);
 211
 212                         if (find_entry(buffer, id, &tmp)) {
 213                                 print_entry_value(&tmp);
 214                                 printf("\n");
 215                                 return EXIT_SUCCESS;
 216                         } else {
 217                                 fprintf(stderr,
 218                                         "ERROR: no value found for name %s!\n",
 219                                         name);
 220                                 return EXIT_FAILURE;
 221                         }
 222                 }
 223         }
 224
 225         fprintf(stderr, "ERROR: Unknown key name %s!\n", name_filter);
 226         return EXIT_FAILURE;
 227 }
 228
 229 static void usage(int status)
 230 {
 231         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
 232
 233         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
 234         fprintf(stream,
 235         "\n"
 236         "Options:\n"
 237         "  -a              list all key value pairs found in the TFFS file/device\n"
 238         "  -b              swap bytes while parsing the TFFS file/device\n"
 239         "  -h              show this screen\n"
 240         "  -i <file>       inspect the given TFFS file/device <file>\n"
 241         "  -l              list all supported keys\n"
 242         "  -n <key name>   display the value of the given key\n"
 243         "  -s <size>       the (max) size of the TFFS file/device <size>\n"
 244         );
 245
 246         exit(status);
 247 }
 248
 249 static int file_exist(char *filename)
 250 {
 251         struct stat buffer;
 252
 253         return stat(filename, &buffer) == 0;
 254 }
 255
 256 static void parse_options(int argc, char *argv[])
 257 {
 258         while (1)
 259         {
 260                 int c;
 261
 262                 c = getopt(argc, argv, "abhi:ln:s");
 263                 if (c == -1)
 264                         break;
 265
 266                 switch (c) {
 267                         case 'a':
 268                                 show_all = true;
 269                                 name_filter = NULL;
 270                                 print_all_key_names = false;
 271                                 break;
 272                         case 'b':
 273                                 swap_bytes = 1;
 274                                 break;
 275                         case 'h':
 276                                 usage(EXIT_SUCCESS);
 277                                 break;
 278                         case 'i':
 279                                 input_file = optarg;
 280                                 break;
 281                         case 'l':
 282                                 print_all_key_names = true;
 283                                 show_all = false;
 284                                 name_filter = NULL;
 285                                 break;
 286                         case 'n':
 287                                 name_filter = optarg;
 288                                 show_all = false;
 289                                 print_all_key_names = false;
 290                                 break;
 291                         case 's':
 292                                 tffs_size = strtoul(optarg, NULL, 0);
 293                                 break;
 294                         default:
 295                                 usage(EXIT_FAILURE);
 296                                 break;
 297                 }
 298         }
 299
 300         if (!input_file) {
 301                 fprintf(stderr, "ERROR: No input file (-i <file>) given!\n");
 302                 exit(EXIT_FAILURE);
 303         }
 304
 305         if (!file_exist(input_file)) {
 306                 fprintf(stderr, "ERROR: %s does not exist\n", input_file);
 307                 exit(EXIT_FAILURE);
 308         }
 309
 310         if (!show_all && !name_filter && !print_all_key_names) {
 311                 fprintf(stderr,
 312                         "ERROR: either -l, -a or -n <key name> is required!\n");
 313                 exit(EXIT_FAILURE);
 314         }
 315 }
 316
 317 int main(int argc, char *argv[])
 318 {
 319         int ret = EXIT_FAILURE;
 320         uint8_t *buffer;
 321         FILE *fp;
 322         struct tffs_entry name_table;
 323         struct tffs_key_name_table key_names;
 324
 325         progname = basename(argv[0]);
 326
 327         parse_options(argc, argv);
 328
 329         fp = fopen(input_file, "r");
 330
 331         if (!fp) {
 332                 fprintf(stderr, "ERROR: Failed to open tffs input file %s\n",
 333                         input_file);
 334                 goto out;
 335         }
 336
 337         buffer = malloc(tffs_size);
 338
 339         if (fread(buffer, 1, tffs_size, fp) != tffs_size) {
 340                 fprintf(stderr, "ERROR: Failed read tffs file %s\n",
 341                         input_file);
 342                 goto out_free;
 343         }
 344
 345         if (!find_entry(buffer, TFFS_ID_TABLE_NAME, &name_table)) {
 346                 fprintf(stderr,"ERROR: No name table found in tffs file %s\n",
 347                         input_file);
 348                 fprintf(stderr,"       Is byte-swapping (-b) required?\n");
 349                 goto out_free;
 350         }
 351
 352         parse_key_names(&name_table, &key_names);
 353         if (key_names.size < 1) {
 354                 fprintf(stderr, "ERROR: No name table found in tffs file %s\n",
 355                         input_file);
 356                 goto out_free_names;
 357         }
 358
 359         if (print_all_key_names) {
 360                 show_all_key_names(&key_names);
 361                 ret = EXIT_SUCCESS;
 362         } else if (show_all) {
 363                 ret = show_all_key_value_pairs(buffer, &key_names);
 364         } else {
 365                 ret = show_matching_key_value(buffer, &key_names);
 366         }
 367
 368 out_free_names:
 369         free(key_names.entries);
 370 out_free:
 371         fclose(fp);
 372         free(buffer);
 373 out:
 374         return ret;
 375 }