package/nvram/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 int length;
  50         unsigned int offset;
  51         struct nvram_tuple *nvram_hash[257];
  52         struct nvram_tuple *nvram_dead;
  53 };
  54
  55 typedef struct nvram_handle nvram_handle_t;
  56 typedef struct nvram_header nvram_header_t;
  57 typedef struct nvram_tuple  nvram_tuple_t;
  58
  59
  60 /* Get nvram header. */
  61 nvram_header_t * nvram_header(nvram_handle_t *h);
  62
  63 /* Set the value of an NVRAM variable */
  64 int nvram_set(nvram_handle_t *h, const char *name, const char *value);
  65
  66 /* Get the value of an NVRAM variable. */
  67 char * nvram_get(nvram_handle_t *h, const char *name);
  68
  69 /* Unset the value of an NVRAM variable. */
  70 int nvram_unset(nvram_handle_t *h, const char *name);
  71
  72 /* Get all NVRAM variables. */
  73 nvram_tuple_t * nvram_getall(nvram_handle_t *h);
  74
  75 /* Regenerate NVRAM. */
  76 int nvram_commit(nvram_handle_t *h);
  77
  78 /* Open NVRAM and obtain a handle. */
  79 nvram_handle_t * nvram_open(const char *file, int rdonly);
  80
  81 /* Close NVRAM and free memory. */
  82 int nvram_close(nvram_handle_t *h);
  83
  84 /* Get the value of an NVRAM variable in a safe way, use "" instead of NULL. */
  85 #define nvram_safe_get(h, name) (nvram_get(h, name) ? : "")
  86
  87 /* Computes a crc8 over the input data. */
  88 uint8_t hndcrc8 (uint8_t * pdata, uint32_t nbytes, uint8_t crc);
  89
  90 /* Returns the crc value of the nvram. */
  91 uint8_t nvram_calc_crc(nvram_header_t * nvh);
  92
  93 /* Determine NVRAM device node. */
  94 char * nvram_find_mtd(void);
  95
  96 /* Copy NVRAM contents to staging file. */
  97 int nvram_to_staging(void);
  98
  99 /* Copy staging file to NVRAM device. */
 100 int staging_to_nvram(void);
 101
 102 /* Check NVRAM staging file. */
 103 char * nvram_find_staging(void);
 104
 105
 106 /* Staging file for NVRAM */
 107 #define NVRAM_STAGING           "/tmp/.nvram"
 108 #define NVRAM_RO                        1
 109 #define NVRAM_RW                        0
 110
 111 /* Helper macros */
 112 #define NVRAM_ARRAYSIZE(a)      sizeof(a)/sizeof(a[0])
 113 #define NVRAM_ROUNDUP(x, y)     ((((x)+((y)-1))/(y))*(y))
 114
 115 /* NVRAM constants */
 116 #define NVRAM_SPACE                     0x8000
 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_ */