package/system/utils/nvram/src/nvram.c

   1 /*
   2  * NVRAM variable manipulation (common)
   3  *
   4  * Copyright 2004, Broadcom Corporation
   5  * Copyright 2009-2010, OpenWrt.org
   6  * All Rights Reserved.
   7  *
   8  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
   9  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
  10  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  11  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  12  *
  13  */
  14
  15 #include "nvram.h"
  16
  17 #define TRACE(msg) \
  18         printf("%s(%i) in %s(): %s\n", \
  19                 __FILE__, __LINE__, __FUNCTION__, msg ? msg : "?")
  20
  21 size_t nvram_erase_size = 0;
  22
  23
  24 /*
  25  * -- Helper functions --
  26  */
  27
  28 /* String hash */
  29 static uint32_t hash(const char *s)
  30 {
  31         uint32_t hash = 0;
  32
  33         while (*s)
  34                 hash = 31 * hash + *s++;
  35
  36         return hash;
  37 }
  38
  39 /* Free all tuples. */
  40 static void _nvram_free(nvram_handle_t *h)
  41 {
  42         uint32_t i;
  43         nvram_tuple_t *t, *next;
  44
  45         /* Free hash table */
  46         for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
  47                 for (t = h->nvram_hash[i]; t; t = next) {
  48                         next = t->next;
  49                         free(t);
  50                 }
  51                 h->nvram_hash[i] = NULL;
  52         }
  53
  54         /* Free dead table */
  55         for (t = h->nvram_dead; t; t = next) {
  56                 next = t->next;
  57                 free(t);
  58         }
  59
  60         h->nvram_dead = NULL;
  61 }
  62
  63 /* (Re)allocate NVRAM tuples. */
  64 static nvram_tuple_t * _nvram_realloc( nvram_handle_t *h, nvram_tuple_t *t,
  65         const char *name, const char *value )
  66 {
  67         if ((strlen(value) + 1) > NVRAM_SPACE)
  68                 return NULL;
  69
  70         if (!t) {
  71                 if (!(t = malloc(sizeof(nvram_tuple_t) + strlen(name) + 1)))
  72                         return NULL;
  73
  74                 /* Copy name */
  75                 t->name = (char *) &t[1];
  76                 strcpy(t->name, name);
  77
  78                 t->value = NULL;
  79         }
  80
  81         /* Copy value */
  82         if (!t->value || strcmp(t->value, value))
  83         {
  84                 if(!(t->value = (char *) realloc(t->value, strlen(value)+1)))
  85                         return NULL;
  86
  87                 strcpy(t->value, value);
  88                 t->value[strlen(value)] = '\0';
  89         }
  90
  91         return t;
  92 }
  93
  94 /* (Re)initialize the hash table. */
  95 static int _nvram_rehash(nvram_handle_t *h)
  96 {
  97         nvram_header_t *header = nvram_header(h);
  98         char buf[] = "0xXXXXXXXX", *name, *value, *eq;
  99
 100         /* (Re)initialize hash table */
 101         _nvram_free(h);
 102
 103         /* Parse and set "name=value\0 ... \0\0" */
 104         name = (char *) &header[1];
 105
 106         for (; *name; name = value + strlen(value) + 1) {
 107                 if (!(eq = strchr(name, '=')))
 108                         break;
 109                 *eq = '\0';
 110                 value = eq + 1;
 111                 nvram_set(h, name, value);
 112                 *eq = '=';
 113         }
 114
 115         /* Set special SDRAM parameters */
 116         if (!nvram_get(h, "sdram_init")) {
 117                 sprintf(buf, "0x%04X", (uint16_t)(header->crc_ver_init >> 16));
 118                 nvram_set(h, "sdram_init", buf);
 119         }
 120         if (!nvram_get(h, "sdram_config")) {
 121                 sprintf(buf, "0x%04X", (uint16_t)(header->config_refresh & 0xffff));
 122                 nvram_set(h, "sdram_config", buf);
 123         }
 124         if (!nvram_get(h, "sdram_refresh")) {
 125                 sprintf(buf, "0x%04X",
 126                         (uint16_t)((header->config_refresh >> 16) & 0xffff));
 127                 nvram_set(h, "sdram_refresh", buf);
 128         }
 129         if (!nvram_get(h, "sdram_ncdl")) {
 130                 sprintf(buf, "0x%08X", header->config_ncdl);
 131                 nvram_set(h, "sdram_ncdl", buf);
 132         }
 133
 134         return 0;
 135 }
 136
 137
 138 /*
 139  * -- Public functions --
 140  */
 141
 142 /* Get nvram header. */
 143 nvram_header_t * nvram_header(nvram_handle_t *h)
 144 {
 145         return (nvram_header_t *) &h->mmap[h->offset];
 146 }
 147
 148 /* Get the value of an NVRAM variable. */
 149 char * nvram_get(nvram_handle_t *h, const char *name)
 150 {
 151         uint32_t i;
 152         nvram_tuple_t *t;
 153         char *value;
 154
 155         if (!name)
 156                 return NULL;
 157
 158         /* Hash the name */
 159         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 160
 161         /* Find the associated tuple in the hash table */
 162         for (t = h->nvram_hash[i]; t && strcmp(t->name, name); t = t->next);
 163
 164         value = t ? t->value : NULL;
 165
 166         return value;
 167 }
 168
 169 /* Set the value of an NVRAM variable. */
 170 int nvram_set(nvram_handle_t *h, const char *name, const char *value)
 171 {
 172         uint32_t i;
 173         nvram_tuple_t *t, *u, **prev;
 174
 175         /* Hash the name */
 176         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 177
 178         /* Find the associated tuple in the hash table */
 179         for (prev = &h->nvram_hash[i], t = *prev;
 180                  t && strcmp(t->name, name); prev = &t->next, t = *prev);
 181
 182         /* (Re)allocate tuple */
 183         if (!(u = _nvram_realloc(h, t, name, value)))
 184                 return -12; /* -ENOMEM */
 185
 186         /* Value reallocated */
 187         if (t && t == u)
 188                 return 0;
 189
 190         /* Move old tuple to the dead table */
 191         if (t) {
 192                 *prev = t->next;
 193                 t->next = h->nvram_dead;
 194                 h->nvram_dead = t;
 195         }
 196
 197         /* Add new tuple to the hash table */
 198         u->next = h->nvram_hash[i];
 199         h->nvram_hash[i] = u;
 200
 201         return 0;
 202 }
 203
 204 /* Unset the value of an NVRAM variable. */
 205 int nvram_unset(nvram_handle_t *h, const char *name)
 206 {
 207         uint32_t i;
 208         nvram_tuple_t *t, **prev;
 209
 210         if (!name)
 211                 return 0;
 212
 213         /* Hash the name */
 214         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 215
 216         /* Find the associated tuple in the hash table */
 217         for (prev = &h->nvram_hash[i], t = *prev;
 218                  t && strcmp(t->name, name); prev = &t->next, t = *prev);
 219
 220         /* Move it to the dead table */
 221         if (t) {
 222                 *prev = t->next;
 223                 t->next = h->nvram_dead;
 224                 h->nvram_dead = t;
 225         }
 226
 227         return 0;
 228 }
 229
 230 /* Get all NVRAM variables. */
 231 nvram_tuple_t * nvram_getall(nvram_handle_t *h)
 232 {
 233         int i;
 234         nvram_tuple_t *t, *l, *x;
 235
 236         l = NULL;
 237
 238         for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
 239                 for (t = h->nvram_hash[i]; t; t = t->next) {
 240                         if( (x = (nvram_tuple_t *) malloc(sizeof(nvram_tuple_t))) != NULL )
 241                         {
 242                                 x->name  = t->name;
 243                                 x->value = t->value;
 244                                 x->next  = l;
 245                                 l = x;
 246                         }
 247                         else
 248                         {
 249                                 break;
 250                         }
 251                 }
 252         }
 253
 254         return l;
 255 }
 256
 257 /* Regenerate NVRAM. */
 258 int nvram_commit(nvram_handle_t *h)
 259 {
 260         nvram_header_t *header = nvram_header(h);
 261         char *init, *config, *refresh, *ncdl;
 262         char *ptr, *end;
 263         int i;
 264         nvram_tuple_t *t;
 265         nvram_header_t tmp;
 266         uint8_t crc;
 267
 268         /* Regenerate header */
 269         header->magic = NVRAM_MAGIC;
 270         header->crc_ver_init = (NVRAM_VERSION << 8);
 271         if (!(init = nvram_get(h, "sdram_init")) ||
 272                 !(config = nvram_get(h, "sdram_config")) ||
 273                 !(refresh = nvram_get(h, "sdram_refresh")) ||
 274                 !(ncdl = nvram_get(h, "sdram_ncdl"))) {
 275                 header->crc_ver_init |= SDRAM_INIT << 16;
 276                 header->config_refresh = SDRAM_CONFIG;
 277                 header->config_refresh |= SDRAM_REFRESH << 16;
 278                 header->config_ncdl = 0;
 279         } else {
 280                 header->crc_ver_init |= (strtoul(init, NULL, 0) & 0xffff) << 16;
 281                 header->config_refresh = strtoul(config, NULL, 0) & 0xffff;
 282                 header->config_refresh |= (strtoul(refresh, NULL, 0) & 0xffff) << 16;
 283                 header->config_ncdl = strtoul(ncdl, NULL, 0);
 284         }
 285
 286         /* Clear data area */
 287         ptr = (char *) header + sizeof(nvram_header_t);
 288         memset(ptr, 0xFF, NVRAM_SPACE - sizeof(nvram_header_t));
 289         memset(&tmp, 0, sizeof(nvram_header_t));
 290
 291         /* Leave space for a double NUL at the end */
 292         end = (char *) header + NVRAM_SPACE - 2;
 293
 294         /* Write out all tuples */
 295         for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
 296                 for (t = h->nvram_hash[i]; t; t = t->next) {
 297                         if ((ptr + strlen(t->name) + 1 + strlen(t->value) + 1) > end)
 298                                 break;
 299                         ptr += sprintf(ptr, "%s=%s", t->name, t->value) + 1;
 300                 }
 301         }
 302
 303         /* End with a double NULL and pad to 4 bytes */
 304         *ptr = '\0';
 305         ptr++;
 306
 307         if( (int)ptr % 4 )
 308                 memset(ptr, 0, 4 - ((int)ptr % 4));
 309
 310         ptr++;
 311
 312         /* Set new length */
 313         header->len = NVRAM_ROUNDUP(ptr - (char *) header, 4);
 314
 315         /* Little-endian CRC8 over the last 11 bytes of the header */
 316         tmp.crc_ver_init   = header->crc_ver_init;
 317         tmp.config_refresh = header->config_refresh;
 318         tmp.config_ncdl    = header->config_ncdl;
 319         crc = hndcrc8((unsigned char *) &tmp + NVRAM_CRC_START_POSITION,
 320                 sizeof(nvram_header_t) - NVRAM_CRC_START_POSITION, 0xff);
 321
 322         /* Continue CRC8 over data bytes */
 323         crc = hndcrc8((unsigned char *) &header[0] + sizeof(nvram_header_t),
 324                 header->len - sizeof(nvram_header_t), crc);
 325
 326         /* Set new CRC8 */
 327         header->crc_ver_init |= crc;
 328
 329         /* Write out */
 330         msync(h->mmap, h->length, MS_SYNC);
 331         fsync(h->fd);
 332
 333         /* Reinitialize hash table */
 334         return _nvram_rehash(h);
 335 }
 336
 337 /* Open NVRAM and obtain a handle. */
 338 nvram_handle_t * nvram_open(const char *file, int rdonly)
 339 {
 340         int i;
 341         int fd;
 342         char *mtd = NULL;
 343         nvram_handle_t *h;
 344         nvram_header_t *header;
 345         int offset = -1;
 346
 347         /* If erase size or file are undefined then try to define them */
 348         if( (nvram_erase_size == 0) || (file == NULL) )
 349         {
 350                 /* Finding the mtd will set the appropriate erase size */
 351                 if( (mtd = nvram_find_mtd()) == NULL || nvram_erase_size == 0 )
 352                 {
 353                         free(mtd);
 354                         return NULL;
 355                 }
 356         }
 357
 358         if( (fd = open(file ? file : mtd, O_RDWR)) > -1 )
 359         {
 360                 char *mmap_area = (char *) mmap(
 361                         NULL, nvram_erase_size, PROT_READ | PROT_WRITE,
 362                         (( rdonly == NVRAM_RO ) ? MAP_PRIVATE : MAP_SHARED) | MAP_LOCKED, fd, 0);
 363
 364                 if( mmap_area != MAP_FAILED )
 365                 {
 366                         for( i = 0; i <= ((nvram_erase_size - NVRAM_SPACE) / sizeof(uint32_t)); i++ )
 367                         {
 368                                 if( ((uint32_t *)mmap_area)[i] == NVRAM_MAGIC )
 369                                 {
 370                                         offset = i * sizeof(uint32_t);
 371                                         break;
 372                                 }
 373                         }
 374
 375                         if( offset < 0 )
 376                         {
 377                                 free(mtd);
 378                                 return NULL;
 379                         }
 380                         else if( (h = malloc(sizeof(nvram_handle_t))) != NULL )
 381                         {
 382                                 memset(h, 0, sizeof(nvram_handle_t));
 383
 384                                 h->fd     = fd;
 385                                 h->mmap   = mmap_area;
 386                                 h->length = nvram_erase_size;
 387                                 h->offset = offset;
 388
 389                                 header = nvram_header(h);
 390
 391                                 if( header->magic == NVRAM_MAGIC )
 392                                 {
 393                                         _nvram_rehash(h);
 394                                         free(mtd);
 395                                         return h;
 396                                 }
 397                                 else
 398                                 {
 399                                         munmap(h->mmap, h->length);
 400                                         free(h);
 401                                 }
 402                         }
 403                 }
 404         }
 405
 406         free(mtd);
 407         return NULL;
 408 }
 409
 410 /* Close NVRAM and free memory. */
 411 int nvram_close(nvram_handle_t *h)
 412 {
 413         _nvram_free(h);
 414         munmap(h->mmap, h->length);
 415         close(h->fd);
 416         free(h);
 417
 418         return 0;
 419 }
 420
 421 /* Determine NVRAM device node. */
 422 char * nvram_find_mtd(void)
 423 {
 424         FILE *fp;
 425         int i, esz;
 426         char dev[PATH_MAX];
 427         char *path = NULL;
 428         struct stat s;
 429         int supported = 1;
 430
 431         /* Refuse any operation on the WGT634U */
 432         if( (fp = fopen("/proc/diag/model", "r")) )
 433         {
 434                 if( fgets(dev, sizeof(dev), fp) && !strncmp(dev, "Netgear WGT634U", 15) )
 435                         supported = 0;
 436
 437                 fclose(fp);
 438         }
 439
 440         if( supported && (fp = fopen("/proc/mtd", "r")) )
 441         {
 442                 while( fgets(dev, sizeof(dev), fp) )
 443                 {
 444                         if( strstr(dev, "nvram") && sscanf(dev, "mtd%d: %08x", &i, &esz) )
 445                         {
 446                                 nvram_erase_size = esz;
 447
 448                                 sprintf(dev, "/dev/mtdblock/%d", i);
 449                                 if( stat(dev, &s) > -1 && (s.st_mode & S_IFBLK) )
 450                                 {
 451                                         if( (path = (char *) malloc(strlen(dev)+1)) != NULL )
 452                                         {
 453                                                 strncpy(path, dev, strlen(dev)+1);
 454                                                 break;
 455                                         }
 456                                 }
 457                                 else
 458                                 {
 459                                         sprintf(dev, "/dev/mtdblock%d", i);
 460                                         if( stat(dev, &s) > -1 && (s.st_mode & S_IFBLK) )
 461                                         {
 462                                                 if( (path = (char *) malloc(strlen(dev)+1)) != NULL )
 463                                                 {
 464                                                         strncpy(path, dev, strlen(dev)+1);
 465                                                         break;
 466                                                 }
 467                                         }
 468                                 }
 469                         }
 470                 }
 471                 fclose(fp);
 472         }
 473
 474         return path;
 475 }
 476
 477 /* Check NVRAM staging file. */
 478 char * nvram_find_staging(void)
 479 {
 480         struct stat s;
 481
 482         if( (stat(NVRAM_STAGING, &s) > -1) && (s.st_mode & S_IFREG) )
 483         {
 484                 return NVRAM_STAGING;
 485         }
 486
 487         return NULL;
 488 }
 489
 490 /* Copy NVRAM contents to staging file. */
 491 int nvram_to_staging(void)
 492 {
 493         int fdmtd, fdstg, stat;
 494         char *mtd = nvram_find_mtd();
 495         char buf[nvram_erase_size];
 496
 497         stat = -1;
 498
 499         if( (mtd != NULL) && (nvram_erase_size > 0) )
 500         {
 501                 if( (fdmtd = open(mtd, O_RDONLY)) > -1 )
 502                 {
 503                         if( read(fdmtd, buf, sizeof(buf)) == sizeof(buf) )
 504                         {
 505                                 if((fdstg = open(NVRAM_STAGING, O_WRONLY | O_CREAT, 0600)) > -1)
 506                                 {
 507                                         write(fdstg, buf, sizeof(buf));
 508                                         fsync(fdstg);
 509                                         close(fdstg);
 510
 511                                         stat = 0;
 512                                 }
 513                         }
 514
 515                         close(fdmtd);
 516                 }
 517         }
 518
 519         free(mtd);
 520         return stat;
 521 }
 522
 523 /* Copy staging file to NVRAM device. */
 524 int staging_to_nvram(void)
 525 {
 526         int fdmtd, fdstg, stat;
 527         char *mtd = nvram_find_mtd();
 528         char buf[nvram_erase_size];
 529
 530         stat = -1;
 531
 532         if( (mtd != NULL) && (nvram_erase_size > 0) )
 533         {
 534                 if( (fdstg = open(NVRAM_STAGING, O_RDONLY)) > -1 )
 535                 {
 536                         if( read(fdstg, buf, sizeof(buf)) == sizeof(buf) )
 537                         {
 538                                 if( (fdmtd = open(mtd, O_WRONLY | O_SYNC)) > -1 )
 539                                 {
 540                                         write(fdmtd, buf, sizeof(buf));
 541                                         fsync(fdmtd);
 542                                         close(fdmtd);
 543                                         stat = 0;
 544                                 }
 545                         }
 546
 547                         close(fdstg);
 548
 549                         if( !stat )
 550                                 stat = unlink(NVRAM_STAGING) ? 1 : 0;
 551                 }
 552         }
 553
 554         free(mtd);
 555         return stat;
 556 }