contrib/userspace-nvram/nvram.c

   1 /*
   2  * NVRAM variable manipulation (common)
   3  *
   4  * Copyright 2004, Broadcom Corporation
   5  * Copyright 2009, 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_t *) &h->mmap[NVRAM_START(nvram_erase_size)];
  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 the value of an NVRAM variable. */
 143 char * nvram_get(nvram_handle_t *h, const char *name)
 144 {
 145         uint32_t i;
 146         nvram_tuple_t *t;
 147         char *value;
 148
 149         if (!name)
 150                 return NULL;
 151
 152         /* Hash the name */
 153         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 154
 155         /* Find the associated tuple in the hash table */
 156         for (t = h->nvram_hash[i]; t && strcmp(t->name, name); t = t->next);
 157
 158         value = t ? t->value : NULL;
 159
 160         return value;
 161 }
 162
 163 /* Set the value of an NVRAM variable. */
 164 int nvram_set(nvram_handle_t *h, const char *name, const char *value)
 165 {
 166         uint32_t i;
 167         nvram_tuple_t *t, *u, **prev;
 168
 169         /* Hash the name */
 170         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 171
 172         /* Find the associated tuple in the hash table */
 173         for (prev = &h->nvram_hash[i], t = *prev;
 174                  t && strcmp(t->name, name); prev = &t->next, t = *prev);
 175
 176         /* (Re)allocate tuple */
 177         if (!(u = _nvram_realloc(h, t, name, value)))
 178                 return -12; /* -ENOMEM */
 179
 180         /* Value reallocated */
 181         if (t && t == u)
 182                 return 0;
 183
 184         /* Move old tuple to the dead table */
 185         if (t) {
 186                 *prev = t->next;
 187                 t->next = h->nvram_dead;
 188                 h->nvram_dead = t;
 189         }
 190
 191         /* Add new tuple to the hash table */
 192         u->next = h->nvram_hash[i];
 193         h->nvram_hash[i] = u;
 194
 195         return 0;
 196 }
 197
 198 /* Unset the value of an NVRAM variable. */
 199 int nvram_unset(nvram_handle_t *h, const char *name)
 200 {
 201         uint32_t i;
 202         nvram_tuple_t *t, **prev;
 203
 204         if (!name)
 205                 return 0;
 206
 207         /* Hash the name */
 208         i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
 209
 210         /* Find the associated tuple in the hash table */
 211         for (prev = &h->nvram_hash[i], t = *prev;
 212                  t && strcmp(t->name, name); prev = &t->next, t = *prev);
 213
 214         /* Move it to the dead table */
 215         if (t) {
 216                 *prev = t->next;
 217                 t->next = h->nvram_dead;
 218                 h->nvram_dead = t;
 219         }
 220
 221         return 0;
 222 }
 223
 224 /* Get all NVRAM variables. */
 225 nvram_tuple_t * nvram_getall(nvram_handle_t *h)
 226 {
 227         int i;
 228         nvram_tuple_t *t, *l, *x;
 229
 230         l = NULL;
 231
 232         for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
 233                 for (t = h->nvram_hash[i]; t; t = t->next) {
 234                         if( (x = (nvram_tuple_t *) malloc(sizeof(nvram_tuple_t))) != NULL )
 235                         {
 236                                 x->name  = t->name;
 237                                 x->value = t->value;
 238                                 x->next  = l;
 239                                 l = x;
 240                         }
 241                         else
 242                         {
 243                                 break;
 244                         }
 245                 }
 246         }
 247
 248         return l;
 249 }
 250
 251 /* Regenerate NVRAM. */
 252 int nvram_commit(nvram_handle_t *h)
 253 {
 254         nvram_header_t *header = (nvram_header_t *) &h->mmap[NVRAM_START(nvram_erase_size)];
 255         char *init, *config, *refresh, *ncdl;
 256         char *ptr, *end;
 257         int i;
 258         nvram_tuple_t *t;
 259         nvram_header_t tmp;
 260         uint8_t crc;
 261
 262         /* Regenerate header */
 263         header->magic = NVRAM_MAGIC;
 264         header->crc_ver_init = (NVRAM_VERSION << 8);
 265         if (!(init = nvram_get(h, "sdram_init")) ||
 266                 !(config = nvram_get(h, "sdram_config")) ||
 267                 !(refresh = nvram_get(h, "sdram_refresh")) ||
 268                 !(ncdl = nvram_get(h, "sdram_ncdl"))) {
 269                 header->crc_ver_init |= SDRAM_INIT << 16;
 270                 header->config_refresh = SDRAM_CONFIG;
 271                 header->config_refresh |= SDRAM_REFRESH << 16;
 272                 header->config_ncdl = 0;
 273         } else {
 274                 header->crc_ver_init |= (strtoul(init, NULL, 0) & 0xffff) << 16;
 275                 header->config_refresh = strtoul(config, NULL, 0) & 0xffff;
 276                 header->config_refresh |= (strtoul(refresh, NULL, 0) & 0xffff) << 16;
 277                 header->config_ncdl = strtoul(ncdl, NULL, 0);
 278         }
 279
 280         /* Clear data area */
 281         ptr = (char *) header + sizeof(nvram_header_t);
 282         memset(ptr, 0xFF, NVRAM_SPACE - sizeof(nvram_header_t));
 283         memset(&tmp, 0, sizeof(nvram_header_t));
 284
 285         /* Leave space for a double NUL at the end */
 286         end = (char *) header + NVRAM_SPACE - 2;
 287
 288         /* Write out all tuples */
 289         for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
 290                 for (t = h->nvram_hash[i]; t; t = t->next) {
 291                         if ((ptr + strlen(t->name) + 1 + strlen(t->value) + 1) > end)
 292                                 break;
 293                         ptr += sprintf(ptr, "%s=%s", t->name, t->value) + 1;
 294                 }
 295         }
 296
 297         /* End with a double NUL */
 298         *ptr = '\0';
 299         ptr += 2;
 300
 301         /* Set new length */
 302         header->len = NVRAM_ROUNDUP(ptr - (char *) header, 4);
 303
 304         /* Little-endian CRC8 over the last 11 bytes of the header */
 305         tmp.crc_ver_init = htonl(header->crc_ver_init);
 306         tmp.config_refresh = htonl(header->config_refresh);
 307         tmp.config_ncdl = htonl(header->config_ncdl);
 308         crc = hndcrc8((unsigned char *) &tmp + 9, sizeof(nvram_header_t) - 9, 0xff);
 309
 310         /* Continue CRC8 over data bytes */
 311         crc = hndcrc8((unsigned char *) &header[1],
 312                 header->len - sizeof(nvram_header_t), crc);
 313
 314         /* Set new CRC8 */
 315         header->crc_ver_init |= crc;
 316
 317         /* Write out */
 318         msync(h->mmap, h->length, MS_SYNC);
 319         fsync(h->fd);
 320
 321         /* Reinitialize hash table */
 322         return _nvram_rehash(h);
 323 }
 324
 325 /* Open NVRAM and obtain a handle. */
 326 nvram_handle_t * nvram_open(const char *file, int rdonly)
 327 {
 328         int fd;
 329         nvram_handle_t *h;
 330         nvram_header_t *header;
 331
 332         /* If erase size or file are undefined then try to define them */
 333         if( (nvram_erase_size == 0) || (file == NULL) )
 334         {
 335                 /* Finding the mtd will set the appropriate erase size */
 336                 if( file == NULL )
 337                         file = nvram_find_mtd();
 338                 else
 339                         (void) nvram_find_mtd();
 340
 341                 if( nvram_erase_size == 0 )
 342                         return NULL;
 343         }
 344
 345         if( (fd = open(file, O_RDWR)) > -1 )
 346         {
 347                 char *mmap_area = (char *) mmap(
 348                         NULL, nvram_erase_size, PROT_READ | PROT_WRITE,
 349                         ( rdonly == NVRAM_RO ) ? MAP_PRIVATE : MAP_SHARED, fd, 0);
 350
 351                 if( mmap_area != MAP_FAILED )
 352                 {
 353                         memset(mmap_area, 0xFF, NVRAM_START(nvram_erase_size));
 354
 355                         if((h = (nvram_handle_t *) malloc(sizeof(nvram_handle_t))) != NULL)
 356                         {
 357                                 memset(h, 0, sizeof(nvram_handle_t));
 358
 359                                 h->fd     = fd;
 360                                 h->mmap   = mmap_area;
 361                                 h->length = nvram_erase_size;
 362
 363                                 header = (nvram_header_t *) &h->mmap[NVRAM_START(nvram_erase_size)];
 364
 365                                 if( header->magic == NVRAM_MAGIC )
 366                                 {
 367                                         _nvram_rehash(h);
 368                                         return h;
 369                                 }
 370                                 else
 371                                 {
 372                                         munmap(h->mmap, h->length);
 373                                         free(h);
 374                                 }
 375                         }
 376                 }
 377         }
 378
 379         return NULL;
 380 }
 381
 382 /* Close NVRAM and free memory. */
 383 int nvram_close(nvram_handle_t *h)
 384 {
 385         _nvram_free(h);
 386         munmap(h->mmap, h->length);
 387         close(h->fd);
 388         free(h);
 389
 390         return 0;
 391 }
 392
 393 /* Determine NVRAM device node. */
 394 const char * nvram_find_mtd(void)
 395 {
 396         FILE *fp;
 397         int i, esz;
 398         char dev[PATH_MAX];
 399         char *path = NULL;
 400
 401         // "/dev/mtdblock/" + ( 0 < x < 99 ) + \0 = 19
 402         if( (path = (char *) malloc(19)) == NULL )
 403                 return NULL;
 404
 405         if ((fp = fopen("/proc/mtd", "r"))) {
 406                 while (fgets(dev, sizeof(dev), fp)) {
 407                         if (strstr(dev, "nvram") && sscanf(dev, "mtd%d: %08x", &i, &esz)) {
 408                                 if( (path = (char *) malloc(19)) != NULL )
 409                                 {
 410                                         nvram_erase_size = esz;
 411                                         snprintf(path, 19, "/dev/mtdblock/%d", i);
 412                                         break;
 413                                 }
 414                         }
 415                 }
 416                 fclose(fp);
 417         }
 418
 419         return path;
 420 }
 421
 422 /* Check NVRAM staging file. */
 423 const char * nvram_find_staging(void)
 424 {
 425         struct stat s;
 426
 427         if( (stat(NVRAM_STAGING, &s) > -1) && (s.st_mode & S_IFREG) )
 428         {
 429                 return NVRAM_STAGING;
 430         }
 431
 432         return NULL;
 433 }
 434
 435 /* Copy NVRAM contents to staging file. */
 436 int nvram_to_staging(void)
 437 {
 438         int fdmtd, fdstg, stat;
 439         const char *mtd = nvram_find_mtd();
 440         char buf[nvram_erase_size];
 441
 442         stat = -1;
 443
 444         if( (mtd != NULL) && (nvram_erase_size > 0) )
 445         {
 446                 if( (fdmtd = open(mtd, O_RDONLY)) > -1 )
 447                 {
 448                         if( read(fdmtd, buf, sizeof(buf)) == sizeof(buf) )
 449                         {
 450                                 if((fdstg = open(NVRAM_STAGING, O_WRONLY | O_CREAT, 0600)) > -1)
 451                                 {
 452                                         write(fdstg, buf, sizeof(buf));
 453                                         fsync(fdstg);
 454                                         close(fdstg);
 455
 456                                         stat = 0;
 457                                 }
 458                         }
 459
 460                         close(fdmtd);
 461                 }
 462         }
 463
 464         return stat;
 465 }
 466
 467 /* Copy staging file to NVRAM device. */
 468 int staging_to_nvram(void)
 469 {
 470         int fdmtd, fdstg, stat;
 471         const char *mtd = nvram_find_mtd();
 472         char buf[nvram_erase_size];
 473
 474         stat = -1;
 475
 476         if( (mtd != NULL) && (nvram_erase_size > 0) )
 477         {
 478                 if( (fdstg = open(NVRAM_STAGING, O_RDONLY)) > -1 )
 479                 {
 480                         if( read(fdstg, buf, sizeof(buf)) == sizeof(buf) )
 481                         {
 482                                 if( (fdmtd = open(mtd, O_WRONLY | O_SYNC)) > -1 )
 483                                 {
 484                                         write(fdmtd, buf, sizeof(buf));
 485                                         fsync(fdmtd);
 486                                         close(fdmtd);
 487                                         stat = 0;
 488                                 }
 489                         }
 490
 491                         close(fdstg);
 492
 493                         if( !stat )
 494                                 stat = unlink(NVRAM_STAGING) ? 1 : 0;
 495                 }
 496         }
 497
 498         return stat;
 499 }