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