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 <sys/ioctl.h>
  28 #include <arpa/inet.h>
  29 #include <linux/limits.h>
  30
  31 #include "sdinitvals.h"
  32
  33
  34 struct nvram_header {
  35         uint32_t magic;
  36         uint32_t len;
  37         uint32_t crc_ver_init;  /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
  38         uint32_t config_refresh;        /* 0:15 sdram_config, 16:31 sdram_refresh */
  39         uint32_t config_ncdl;   /* ncdl values for memc */
  40 } __attribute__((__packed__));
  41
  42 struct nvram_tuple {
  43         char *name;
  44         char *value;
  45         struct nvram_tuple *next;
  46 };
  47
  48 struct nvram_handle {
  49         int fd;
  50         char *mmap;
  51         unsigned long length;
  52         struct nvram_tuple *nvram_hash[257];
  53         struct nvram_tuple *nvram_dead;
  54 };
  55
  56 typedef struct nvram_handle nvram_handle_t;
  57 typedef struct nvram_header nvram_header_t;
  58 typedef struct nvram_tuple  nvram_tuple_t;
  59
  60
  61 /* Get nvram header. */
  62 nvram_header_t * nvram_header(nvram_handle_t *h);
  63
  64 /* Set the value of an NVRAM variable */
  65 int nvram_set(nvram_handle_t *h, const char *name, const char *value);
  66
  67 /* Get the value of an NVRAM variable. */
  68 char * nvram_get(nvram_handle_t *h, const char *name);
  69
  70 /* Unset the value of an NVRAM variable. */
  71 int nvram_unset(nvram_handle_t *h, const char *name);
  72
  73 /* Get all NVRAM variables. */
  74 nvram_tuple_t * nvram_getall(nvram_handle_t *h);
  75
  76 /* Regenerate NVRAM. */
  77 int nvram_commit(nvram_handle_t *h);
  78
  79 /* Open NVRAM and obtain a handle. */
  80 nvram_handle_t * nvram_open(const char *file, int rdonly);
  81
  82 /* Close NVRAM and free memory. */
  83 int nvram_close(nvram_handle_t *h);
  84
  85 /* Get the value of an NVRAM variable in a safe way, use "" instead of NULL. */
  86 #define nvram_safe_get(h, name) (nvram_get(h, name) ? : "")
  87
  88 /* Computes a crc8 over the input data. */
  89 uint8_t hndcrc8 (uint8_t * pdata, uint32_t nbytes, uint8_t crc);
  90
  91 /* Returns the crc value of the nvram. */
  92 uint8_t nvram_calc_crc(nvram_header_t * nvh);
  93
  94 /* Determine NVRAM device node. */
  95 const char * nvram_find_mtd(void);
  96
  97 /* Copy NVRAM contents to staging file. */
  98 int nvram_to_staging(void);
  99
 100 /* Copy staging file to NVRAM device. */
 101 int staging_to_nvram(void);
 102
 103 /* Check NVRAM staging file. */
 104 const char * nvram_find_staging(void);
 105
 106
 107 /* Staging file for NVRAM */
 108 #define NVRAM_STAGING           "/tmp/.nvram"
 109 #define NVRAM_RO                        1
 110 #define NVRAM_RW                        0
 111
 112 /* Helper macros */
 113 #define NVRAM_ARRAYSIZE(a)      sizeof(a)/sizeof(a[0])
 114 #define NVRAM_ROUNDUP(x, y)     ((((x)+((y)-1))/(y))*(y))
 115
 116 /* NVRAM constants */
 117 #define NVRAM_SPACE                     0x8000
 118 #define NVRAM_START(x)          x - NVRAM_SPACE
 119 #define NVRAM_MAGIC                     0x48534C46      /* 'FLSH' */
 120 #define NVRAM_VERSION           1
 121
 122 #define NVRAM_CRC_START_POSITION        9 /* magic, len, crc8 to be skipped */
 123
 124
 125 #endif /* _nvram_h_ */