package/unvram/src/nvram.h

   1 /*
   2  * NVRAM variable manipulation
   3  *
   4  * Copyright 2007, 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 #ifndef _nvram_h_
  16 #define _nvram_h_
  17
  18 #include <stdint.h>
  19 #include <string.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <fcntl.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <sys/mman.h>
  26 #include <sys/stat.h>
  27 #include <linux/limits.h>
  28
  29 #include "sdinitvals.h"
  30
  31
  32 struct nvram_header {
  33         uint32_t magic;
  34         uint32_t len;
  35         uint32_t crc_ver_init;  /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
  36         uint32_t config_refresh;        /* 0:15 sdram_config, 16:31 sdram_refresh */
  37         uint32_t config_ncdl;   /* ncdl values for memc */
  38 } __attribute__((__packed__));
  39
  40 struct nvram_tuple {
  41         char *name;
  42         char *value;
  43         struct nvram_tuple *next;
  44 };
  45
  46 struct nvram_handle {
  47         int fd;
  48         char *mmap;
  49         unsigned long length;
  50         struct nvram_tuple *nvram_hash[257];
  51         struct nvram_tuple *nvram_dead;
  52 };
  53
  54 typedef struct nvram_handle nvram_handle_t;
  55 typedef struct nvram_header nvram_header_t;
  56 typedef struct nvram_tuple  nvram_tuple_t;
  57
  58
  59 /* Get nvram header. */
  60 nvram_header_t * nvram_header(nvram_handle_t *h);
  61
  62 /* Set the value of an NVRAM variable */
  63 int nvram_set(nvram_handle_t *h, const char *name, const char *value);
  64
  65 /* Get the value of an NVRAM variable. */
  66 char * nvram_get(nvram_handle_t *h, const char *name);
  67
  68 /* Unset the value of an NVRAM variable. */
  69 int nvram_unset(nvram_handle_t *h, const char *name);
  70
  71 /* Get all NVRAM variables. */
  72 nvram_tuple_t * nvram_getall(nvram_handle_t *h);
  73
  74 /* Regenerate NVRAM. */
  75 int nvram_commit(nvram_handle_t *h);
  76
  77 /* Open NVRAM and obtain a handle. */
  78 nvram_handle_t * nvram_open(const char *file, int rdonly);
  79
  80 /* Close NVRAM and free memory. */
  81 int nvram_close(nvram_handle_t *h);
  82
  83 /* Get the value of an NVRAM variable in a safe way, use "" instead of NULL. */
  84 #define nvram_safe_get(h, name) (nvram_get(h, name) ? : "")
  85
  86 /* Computes a crc8 over the input data. */
  87 uint8_t hndcrc8 (uint8_t * pdata, uint32_t nbytes, uint8_t crc);
  88
  89 /* Returns the crc value of the nvram. */
  90 uint8_t nvram_calc_crc(nvram_header_t * nvh);
  91
  92 /* Determine NVRAM device node. */
  93 const char * nvram_find_mtd(void);
  94
  95 /* Copy NVRAM contents to staging file. */
  96 int nvram_to_staging(void);
  97
  98 /* Copy staging file to NVRAM device. */
  99 int staging_to_nvram(void);
 100
 101 /* Check NVRAM staging file. */
 102 const char * nvram_find_staging(void);
 103
 104
 105 /* Staging file for NVRAM */
 106 #define NVRAM_STAGING           "/tmp/.nvram"
 107 #define NVRAM_RO                        1
 108 #define NVRAM_RW                        0
 109
 110 /* Helper macros */
 111 #define NVRAM_ARRAYSIZE(a)      sizeof(a)/sizeof(a[0])
 112 #define NVRAM_ROUNDUP(x, y)     ((((x)+((y)-1))/(y))*(y))
 113
 114 /* NVRAM constants */
 115 #define NVRAM_SPACE                     0x8000
 116 #define NVRAM_START(x)          x - NVRAM_SPACE
 117 #define NVRAM_MAGIC                     0x48534C46      /* 'FLSH' */
 118 #define NVRAM_VERSION           1
 119
 120 #define NVRAM_CRC_START_POSITION        9 /* magic, len, crc8 to be skipped */
 121
 122
 123 #endif /* _nvram_h_ */