package/utils/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 TFFS_ID_END             0xffff
  40 #define TFFS_ID_TABLE_NAME      0x01ff
  41
  42 static char *progname;
  43 static char *input_file;
  44 static unsigned long tffs_size;
  45 static char *name_filter = NULL;
  46 static bool show_all = false;
  47 static bool print_all_key_names = false;
  48 static bool swap_bytes = false;
  49
  50 struct tffs_entry_header {
  51         uint16_t id;
  52         uint16_t len;
  53 };
  54
  55 struct tffs_entry {
  56         const struct tffs_entry_header *header;
  57         char *name;
  58         uint8_t *val;
  59 };
  60
  61 struct tffs_name_table_entry {
  62         const uint32_t *id;
  63         const char *val;
  64 };
  65
  66 struct tffs_key_name_table {
  67         uint32_t size;
  68         struct tffs_name_table_entry *entries;
  69 };
  70
  71 static inline uint16_t get_header_len(const struct tffs_entry_header *header)
  72 {
  73         if (swap_bytes)
  74                 return ntohs(header->len);
  75
  76         return header->len;
  77 }
  78
  79 static inline uint16_t get_header_id(const struct tffs_entry_header *header)
  80 {
  81         if (swap_bytes)
  82                 return ntohs(header->id);
  83
  84         return header->id;
  85 }
  86
  87 static inline uint16_t to_entry_header_id(uint32_t name_id)
  88 {
  89         if (swap_bytes)
  90                 return ntohl(name_id) & 0xffff;
  91
  92         return name_id & 0xffff;
  93 }
  94
  95 static inline uint32_t get_walk_size(uint32_t entry_len)
  96 {
  97         return (entry_len + 3) & ~0x03;
  98 }
  99
 100 static void print_entry_value(const struct tffs_entry *entry)
 101 {
 102         int i;
 103
 104         /* These are NOT NULL terminated. */
 105         for (i = 0; i < get_header_len(entry->header); i++)
 106                 fprintf(stdout, "%c", entry->val[i]);
 107 }
 108
 109 static void parse_entry(uint8_t *buffer, uint32_t pos,
 110                         struct tffs_entry *entry)
 111 {
 112         entry->header = (struct tffs_entry_header *) &buffer[pos];
 113         entry->val = &buffer[pos + sizeof(struct tffs_entry_header)];
 114 }
 115
 116 static int find_entry(uint8_t *buffer, uint16_t id, struct tffs_entry *entry)
 117 {
 118         uint32_t pos = 0;
 119
 120         do {
 121                 parse_entry(buffer, pos, entry);
 122
 123                 if (get_header_id(entry->header) == id)
 124                         return 1;
 125
 126                 pos += sizeof(struct tffs_entry_header);
 127                 pos += get_walk_size(get_header_len(entry->header));
 128         } while (pos < tffs_size && entry->header->id != TFFS_ID_END);
 129
 130         return 0;
 131 }
 132
 133 static void parse_key_names(struct tffs_entry *names_entry,
 134                             struct tffs_key_name_table *key_names)
 135 {
 136         uint32_t pos = 0, i = 0;
 137         struct tffs_name_table_entry *name_item;
 138
 139         key_names->entries = calloc(sizeof(*name_item), 1);
 140
 141         do {
 142                 name_item = &key_names->entries[i];
 143
 144                 name_item->id = (uint32_t *) &names_entry->val[pos];
 145                 pos += sizeof(*name_item->id);
 146                 name_item->val = (const char *) &names_entry->val[pos];
 147
 148                 /*
 149                  * There is no "length" field because the string values are
 150                  * simply NULL-terminated -> strlen() gives us the size.
 151                  */
 152                 pos += get_walk_size(strlen(name_item->val) + 1);
 153
 154                 ++i;
 155                 key_names->entries = realloc(key_names->entries,
 156                                                 sizeof(*name_item) * (i + 1));
 157         } while (pos < get_header_len(names_entry->header));
 158
 159         key_names->size = i;
 160 }
 161
 162 static void show_all_key_names(struct tffs_key_name_table *key_names)
 163 {
 164         int i;
 165
 166         for (i = 0; i < key_names->size; i++)
 167                 printf("%s\n", key_names->entries[i].val);
 168 }
 169
 170 static int show_all_key_value_pairs(uint8_t *buffer,
 171                                     struct tffs_key_name_table *key_names)
 172 {
 173         int i, has_value = 0;
 174         uint16_t id;
 175         struct tffs_entry tmp;
 176
 177         for (i = 0; i < key_names->size; i++) {
 178                 id = to_entry_header_id(*key_names->entries[i].id);
 179
 180                 if (find_entry(buffer, id, &tmp)) {
 181                         printf("%s=", key_names->entries[i].val);
 182                         print_entry_value(&tmp);
 183                         printf("\n");
 184                         has_value++;
 185                 }
 186         }
 187
 188         if (!has_value) {
 189                 fprintf(stderr, "ERROR: no values found!\n");
 190                 return EXIT_FAILURE;
 191         }
 192
 193         return EXIT_SUCCESS;
 194 }
 195
 196 static int show_matching_key_value(uint8_t *buffer,
 197                                    struct tffs_key_name_table *key_names)
 198 {
 199         int i;
 200         uint16_t id;
 201         struct tffs_entry tmp;
 202         const char *name;
 203
 204         for (i = 0; i < key_names->size; i++) {
 205                 name = key_names->entries[i].val;
 206
 207                 if (strncmp(name, name_filter, strlen(name)) == 0) {
 208                         id = to_entry_header_id(*key_names->entries[i].id);
 209
 210                         if (find_entry(buffer, id, &tmp)) {
 211                                 print_entry_value(&tmp);
 212                                 printf("\n");
 213                                 return EXIT_SUCCESS;
 214                         } else {
 215                                 fprintf(stderr,
 216                                         "ERROR: no value found for name %s!\n",
 217                                         name);
 218                                 return EXIT_FAILURE;
 219                         }
 220                 }
 221         }
 222
 223         fprintf(stderr, "ERROR: Unknown key name %s!\n", name_filter);
 224         return EXIT_FAILURE;
 225 }
 226
 227 static void usage(int status)
 228 {
 229         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
 230
 231         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
 232         fprintf(stream,
 233         "\n"
 234         "Options:\n"
 235         "  -a              list all key value pairs found in the TFFS file/device\n"
 236         "  -b              swap bytes while parsing the TFFS file/device\n"
 237         "  -h              show this screen\n"
 238         "  -i <file>       inspect the given TFFS file/device <file>\n"
 239         "  -l              list all supported keys\n"
 240         "  -n <key name>   display the value of the given key\n"
 241         "  -s <size>       the (max) size of the TFFS file/device <size>\n"
 242         );
 243
 244         exit(status);
 245 }
 246
 247 static int file_exist(char *filename)
 248 {
 249         struct stat buffer;
 250
 251         return stat(filename, &buffer) == 0;
 252 }
 253
 254 static void parse_options(int argc, char *argv[])
 255 {
 256         while (1)
 257         {
 258                 int c;
 259
 260                 c = getopt(argc, argv, "abhi:ln:s:");
 261                 if (c == -1)
 262                         break;
 263
 264                 switch (c) {
 265                         case 'a':
 266                                 show_all = true;
 267                                 name_filter = NULL;
 268                                 print_all_key_names = false;
 269                                 break;
 270                         case 'b':
 271                                 swap_bytes = 1;
 272                                 break;
 273                         case 'h':
 274                                 usage(EXIT_SUCCESS);
 275                                 break;
 276                         case 'i':
 277                                 input_file = optarg;
 278                                 break;
 279                         case 'l':
 280                                 print_all_key_names = true;
 281                                 show_all = false;
 282                                 name_filter = NULL;
 283                                 break;
 284                         case 'n':
 285                                 name_filter = optarg;
 286                                 show_all = false;
 287                                 print_all_key_names = false;
 288                                 break;
 289                         case 's':
 290                                 tffs_size = strtoul(optarg, NULL, 0);
 291                                 break;
 292                         default:
 293                                 usage(EXIT_FAILURE);
 294                                 break;
 295                 }
 296         }
 297
 298         if (!input_file) {
 299                 fprintf(stderr, "ERROR: No input file (-i <file>) given!\n");
 300                 exit(EXIT_FAILURE);
 301         }
 302
 303         if (!file_exist(input_file)) {
 304                 fprintf(stderr, "ERROR: %s does not exist\n", input_file);
 305                 exit(EXIT_FAILURE);
 306         }
 307
 308         if (!show_all && !name_filter && !print_all_key_names) {
 309                 fprintf(stderr,
 310                         "ERROR: either -l, -a or -n <key name> is required!\n");
 311                 exit(EXIT_FAILURE);
 312         }
 313 }
 314
 315 int main(int argc, char *argv[])
 316 {
 317         int ret = EXIT_FAILURE;
 318         uint8_t *buffer;
 319         FILE *fp;
 320         struct tffs_entry name_table;
 321         struct tffs_key_name_table key_names;
 322
 323         progname = basename(argv[0]);
 324
 325         parse_options(argc, argv);
 326
 327         fp = fopen(input_file, "r");
 328
 329         if (!fp) {
 330                 fprintf(stderr, "ERROR: Failed to open tffs input file %s\n",
 331                         input_file);
 332                 goto out;
 333         }
 334
 335         if (tffs_size == 0) {
 336                 fseek(fp, 0L, SEEK_END);
 337                 tffs_size = ftell(fp);
 338                 fseek(fp, 0L, SEEK_SET);
 339         }
 340
 341         buffer = malloc(tffs_size);
 342
 343         if (fread(buffer, 1, tffs_size, fp) != tffs_size) {
 344                 fprintf(stderr, "ERROR: Failed read tffs file %s\n",
 345                         input_file);
 346                 goto out_free;
 347         }
 348
 349         if (!find_entry(buffer, TFFS_ID_TABLE_NAME, &name_table)) {
 350                 fprintf(stderr,"ERROR: No name table found in tffs file %s\n",
 351                         input_file);
 352                 fprintf(stderr,"       Is byte-swapping (-b) required?\n");
 353                 goto out_free;
 354         }
 355
 356         parse_key_names(&name_table, &key_names);
 357         if (key_names.size < 1) {
 358                 fprintf(stderr, "ERROR: No name table found in tffs file %s\n",
 359                         input_file);
 360                 goto out_free_names;
 361         }
 362
 363         if (print_all_key_names) {
 364                 show_all_key_names(&key_names);
 365                 ret = EXIT_SUCCESS;
 366         } else if (show_all) {
 367                 ret = show_all_key_value_pairs(buffer, &key_names);
 368         } else {
 369                 ret = show_matching_key_value(buffer, &key_names);
 370         }
 371
 372 out_free_names:
 373         free(key_names.entries);
 374 out_free:
 375         fclose(fp);
 376         free(buffer);
 377 out:
 378         return ret;
 379 }