OpenWrt – Rev 1
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/*
* NVRAM variable manipulation (common)
*
* Copyright 2004, Broadcom Corporation
* Copyright 2009-2010, OpenWrt.org
* All Rights Reserved.
*
* THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
* KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
* SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
*
*/
#include "nvram.h"
#define TRACE(msg) \
printf("%s(%i) in %s(): %s\n", \
__FILE__, __LINE__, __FUNCTION__, msg ? msg : "?")
/* Size of "nvram" MTD partition */
size_t nvram_part_size = 0;
/*
* -- Helper functions --
*/
/* String hash */
static uint32_t hash(const char *s)
{
uint32_t hash = 0;
while (*s)
hash = 31 * hash + *s++;
return hash;
}
/* Free all tuples. */
static void _nvram_free(nvram_handle_t *h)
{
uint32_t i;
nvram_tuple_t *t, *next;
/* Free hash table */
for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
for (t = h->nvram_hash[i]; t; t = next) {
next = t->next;
if (t->value)
free(t->value);
free(t);
}
h->nvram_hash[i] = NULL;
}
/* Free dead table */
for (t = h->nvram_dead; t; t = next) {
next = t->next;
if (t->value)
free(t->value);
free(t);
}
h->nvram_dead = NULL;
}
/* (Re)allocate NVRAM tuples. */
static nvram_tuple_t * _nvram_realloc( nvram_handle_t *h, nvram_tuple_t *t,
const char *name, const char *value )
{
if ((strlen(value) + 1) > h->length - h->offset)
return NULL;
if (!t) {
if (!(t = malloc(sizeof(nvram_tuple_t) + strlen(name) + 1)))
return NULL;
/* Copy name */
t->name = (char *) &t[1];
strcpy(t->name, name);
t->value = NULL;
}
/* Copy value */
if (!t->value || strcmp(t->value, value))
{
if(!(t->value = (char *) realloc(t->value, strlen(value)+1)))
return NULL;
strcpy(t->value, value);
t->value[strlen(value)] = '\0';
}
return t;
}
/* (Re)initialize the hash table. */
static int _nvram_rehash(nvram_handle_t *h)
{
nvram_header_t *header = nvram_header(h);
char buf[] = "0xXXXXXXXX", *name, *value, *eq;
/* (Re)initialize hash table */
_nvram_free(h);
/* Parse and set "name=value\0 ... \0\0" */
name = (char *) &header[1];
for (; *name; name = value + strlen(value) + 1) {
if (!(eq = strchr(name, '=')))
break;
*eq = '\0';
value = eq + 1;
nvram_set(h, name, value);
*eq = '=';
}
/* Set special SDRAM parameters */
if (!nvram_get(h, "sdram_init")) {
sprintf(buf, "0x%04X", (uint16_t)(header->crc_ver_init >> 16));
nvram_set(h, "sdram_init", buf);
}
if (!nvram_get(h, "sdram_config")) {
sprintf(buf, "0x%04X", (uint16_t)(header->config_refresh & 0xffff));
nvram_set(h, "sdram_config", buf);
}
if (!nvram_get(h, "sdram_refresh")) {
sprintf(buf, "0x%04X",
(uint16_t)((header->config_refresh >> 16) & 0xffff));
nvram_set(h, "sdram_refresh", buf);
}
if (!nvram_get(h, "sdram_ncdl")) {
sprintf(buf, "0x%08X", header->config_ncdl);
nvram_set(h, "sdram_ncdl", buf);
}
return 0;
}
/*
* -- Public functions --
*/
/* Get nvram header. */
nvram_header_t * nvram_header(nvram_handle_t *h)
{
return (nvram_header_t *) &h->mmap[h->offset];
}
/* Get the value of an NVRAM variable. */
char * nvram_get(nvram_handle_t *h, const char *name)
{
uint32_t i;
nvram_tuple_t *t;
char *value;
if (!name)
return NULL;
/* Hash the name */
i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
/* Find the associated tuple in the hash table */
for (t = h->nvram_hash[i]; t && strcmp(t->name, name); t = t->next);
value = t ? t->value : NULL;
return value;
}
/* Set the value of an NVRAM variable. */
int nvram_set(nvram_handle_t *h, const char *name, const char *value)
{
uint32_t i;
nvram_tuple_t *t, *u, **prev;
/* Hash the name */
i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
/* Find the associated tuple in the hash table */
for (prev = &h->nvram_hash[i], t = *prev;
t && strcmp(t->name, name); prev = &t->next, t = *prev);
/* (Re)allocate tuple */
if (!(u = _nvram_realloc(h, t, name, value)))
return -12; /* -ENOMEM */
/* Value reallocated */
if (t && t == u)
return 0;
/* Move old tuple to the dead table */
if (t) {
*prev = t->next;
t->next = h->nvram_dead;
h->nvram_dead = t;
}
/* Add new tuple to the hash table */
u->next = h->nvram_hash[i];
h->nvram_hash[i] = u;
return 0;
}
/* Unset the value of an NVRAM variable. */
int nvram_unset(nvram_handle_t *h, const char *name)
{
uint32_t i;
nvram_tuple_t *t, **prev;
if (!name)
return 0;
/* Hash the name */
i = hash(name) % NVRAM_ARRAYSIZE(h->nvram_hash);
/* Find the associated tuple in the hash table */
for (prev = &h->nvram_hash[i], t = *prev;
t && strcmp(t->name, name); prev = &t->next, t = *prev);
/* Move it to the dead table */
if (t) {
*prev = t->next;
t->next = h->nvram_dead;
h->nvram_dead = t;
}
return 0;
}
/* Get all NVRAM variables. */
nvram_tuple_t * nvram_getall(nvram_handle_t *h)
{
int i;
nvram_tuple_t *t, *l, *x;
l = NULL;
for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
for (t = h->nvram_hash[i]; t; t = t->next) {
if( (x = (nvram_tuple_t *) malloc(sizeof(nvram_tuple_t))) != NULL )
{
x->name = t->name;
x->value = t->value;
x->next = l;
l = x;
}
else
{
break;
}
}
}
return l;
}
/* Regenerate NVRAM. */
int nvram_commit(nvram_handle_t *h)
{
nvram_header_t *header = nvram_header(h);
char *init, *config, *refresh, *ncdl;
char *ptr, *end;
int i;
nvram_tuple_t *t;
nvram_header_t tmp;
uint8_t crc;
/* Regenerate header */
header->magic = NVRAM_MAGIC;
header->crc_ver_init = (NVRAM_VERSION << 8);
if (!(init = nvram_get(h, "sdram_init")) ||
!(config = nvram_get(h, "sdram_config")) ||
!(refresh = nvram_get(h, "sdram_refresh")) ||
!(ncdl = nvram_get(h, "sdram_ncdl"))) {
header->crc_ver_init |= SDRAM_INIT << 16;
header->config_refresh = SDRAM_CONFIG;
header->config_refresh |= SDRAM_REFRESH << 16;
header->config_ncdl = 0;
} else {
header->crc_ver_init |= (strtoul(init, NULL, 0) & 0xffff) << 16;
header->config_refresh = strtoul(config, NULL, 0) & 0xffff;
header->config_refresh |= (strtoul(refresh, NULL, 0) & 0xffff) << 16;
header->config_ncdl = strtoul(ncdl, NULL, 0);
}
/* Clear data area */
ptr = (char *) header + sizeof(nvram_header_t);
memset(ptr, 0xFF, nvram_part_size - h->offset - sizeof(nvram_header_t));
memset(&tmp, 0, sizeof(nvram_header_t));
/* Leave space for a double NUL at the end */
end = (char *) header + nvram_part_size - h->offset - 2;
/* Write out all tuples */
for (i = 0; i < NVRAM_ARRAYSIZE(h->nvram_hash); i++) {
for (t = h->nvram_hash[i]; t; t = t->next) {
if ((ptr + strlen(t->name) + 1 + strlen(t->value) + 1) > end)
break;
ptr += sprintf(ptr, "%s=%s", t->name, t->value) + 1;
}
}
/* End with a double NULL and pad to 4 bytes */
*ptr = '\0';
ptr++;
if( (int)ptr % 4 )
memset(ptr, 0, 4 - ((int)ptr % 4));
ptr++;
/* Set new length */
header->len = NVRAM_ROUNDUP(ptr - (char *) header, 4);
/* Little-endian CRC8 over the last 11 bytes of the header */
tmp.crc_ver_init = header->crc_ver_init;
tmp.config_refresh = header->config_refresh;
tmp.config_ncdl = header->config_ncdl;
crc = hndcrc8((unsigned char *) &tmp + NVRAM_CRC_START_POSITION,
sizeof(nvram_header_t) - NVRAM_CRC_START_POSITION, 0xff);
/* Continue CRC8 over data bytes */
crc = hndcrc8((unsigned char *) &header[0] + sizeof(nvram_header_t),
header->len - sizeof(nvram_header_t), crc);
/* Set new CRC8 */
header->crc_ver_init |= crc;
/* Write out */
msync(h->mmap, h->length, MS_SYNC);
fsync(h->fd);
/* Reinitialize hash table */
return _nvram_rehash(h);
}
/* Open NVRAM and obtain a handle. */
nvram_handle_t * nvram_open(const char *file, int rdonly)
{
int i;
int fd;
char *mtd = NULL;
nvram_handle_t *h;
nvram_header_t *header;
int offset = -1;
/* If erase size or file are undefined then try to define them */
if( (nvram_part_size == 0) || (file == NULL) )
{
/* Finding the mtd will set the appropriate erase size */
if( (mtd = nvram_find_mtd()) == NULL || nvram_part_size == 0 )
{
free(mtd);
return NULL;
}
}
if( (fd = open(file ? file : mtd, O_RDWR)) > -1 )
{
char *mmap_area = (char *) mmap(
NULL, nvram_part_size, PROT_READ | PROT_WRITE,
(( rdonly == NVRAM_RO ) ? MAP_PRIVATE : MAP_SHARED) | MAP_LOCKED, fd, 0);
if( mmap_area != MAP_FAILED )
{
/*
* Start looking for NVRAM_MAGIC at beginning of MTD
* partition. Stop if there is less than NVRAM_MIN_SPACE
* to check, that was the lowest used size.
*/
for( i = 0; i <= ((nvram_part_size - NVRAM_MIN_SPACE) / sizeof(uint32_t)); i++ )
{
if( ((uint32_t *)mmap_area)[i] == NVRAM_MAGIC )
{
offset = i * sizeof(uint32_t);
break;
}
}
if( offset < 0 )
{
munmap(mmap_area, nvram_part_size);
free(mtd);
close(fd);
return NULL;
}
else if( (h = malloc(sizeof(nvram_handle_t))) != NULL )
{
memset(h, 0, sizeof(nvram_handle_t));
h->fd = fd;
h->mmap = mmap_area;
h->length = nvram_part_size;
h->offset = offset;
header = nvram_header(h);
if (header->magic == NVRAM_MAGIC &&
(rdonly || header->len < h->length - h->offset)) {
_nvram_rehash(h);
free(mtd);
return h;
}
else
{
munmap(h->mmap, h->length);
free(h);
}
}
}
}
free(mtd);
close(fd);
return NULL;
}
/* Close NVRAM and free memory. */
int nvram_close(nvram_handle_t *h)
{
_nvram_free(h);
munmap(h->mmap, h->length);
close(h->fd);
free(h);
return 0;
}
/* Determine NVRAM device node. */
char * nvram_find_mtd(void)
{
FILE *fp;
int i, part_size;
char dev[PATH_MAX];
char *path = NULL;
struct stat s;
if ((fp = fopen("/proc/mtd", "r")))
{
while( fgets(dev, sizeof(dev), fp) )
{
if( strstr(dev, "nvram") && sscanf(dev, "mtd%d: %08x", &i, &part_size) )
{
nvram_part_size = part_size;
sprintf(dev, "/dev/mtdblock%d", i);
if( stat(dev, &s) > -1 && (s.st_mode & S_IFBLK) )
{
if( (path = (char *) malloc(strlen(dev)+1)) != NULL )
{
strncpy(path, dev, strlen(dev)+1);
break;
}
}
}
}
fclose(fp);
}
return path;
}
/* Check NVRAM staging file. */
char * nvram_find_staging(void)
{
struct stat s;
if( (stat(NVRAM_STAGING, &s) > -1) && (s.st_mode & S_IFREG) )
{
return NVRAM_STAGING;
}
return NULL;
}
/* Copy NVRAM contents to staging file. */
int nvram_to_staging(void)
{
int fdmtd, fdstg, stat;
char *mtd = nvram_find_mtd();
char buf[nvram_part_size];
stat = -1;
if( (mtd != NULL) && (nvram_part_size > 0) )
{
if( (fdmtd = open(mtd, O_RDONLY)) > -1 )
{
if( read(fdmtd, buf, sizeof(buf)) == sizeof(buf) )
{
if((fdstg = open(NVRAM_STAGING, O_WRONLY | O_CREAT, 0600)) > -1)
{
write(fdstg, buf, sizeof(buf));
fsync(fdstg);
close(fdstg);
stat = 0;
}
}
close(fdmtd);
}
}
free(mtd);
return stat;
}
/* Copy staging file to NVRAM device. */
int staging_to_nvram(void)
{
int fdmtd, fdstg, stat;
char *mtd = nvram_find_mtd();
char buf[nvram_part_size];
stat = -1;
if( (mtd != NULL) && (nvram_part_size > 0) )
{
if( (fdstg = open(NVRAM_STAGING, O_RDONLY)) > -1 )
{
if( read(fdstg, buf, sizeof(buf)) == sizeof(buf) )
{
if( (fdmtd = open(mtd, O_WRONLY | O_SYNC)) > -1 )
{
write(fdmtd, buf, sizeof(buf));
fsync(fdmtd);
close(fdmtd);
stat = 0;
}
}
close(fdstg);
if( !stat )
stat = unlink(NVRAM_STAGING) ? 1 : 0;
}
}
free(mtd);
return stat;
}