package/nvram/src/nvram.c

   1 /*
   2  * NVRAM variable manipulation (Linux user mode half)
   3  *
   4  * Copyright 2004, Broadcom Corporation
   5  * All Rights Reserved.
   6  *
   7  * THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
   8  * KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
   9  * SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
  10  * FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
  11  *
  12  */
  13
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <error.h>
  19 #include <string.h>
  20 #include <sys/ioctl.h>
  21 #include <sys/types.h>
  22 #include <sys/stat.h>
  23 #include <fcntl.h>
  24 #include <sys/mman.h>
  25
  26 #include <typedefs.h>
  27 #include <bcmnvram.h>
  28 #include <shutils.h>
  29
  30 #define PATH_DEV_NVRAM "/dev/nvram"
  31
  32 /* Globals */
  33 static int nvram_fd = -1;
  34 static char *nvram_buf = NULL;
  35 int file_to_buf(char *path, char *buf, int len);
  36
  37 int
  38 nvram_init(void *unused)
  39 {
  40         if ((nvram_fd = open(PATH_DEV_NVRAM, O_RDWR)) < 0)
  41                 goto err;
  42
  43         /* Map kernel string buffer into user space */
  44         if ((nvram_buf = mmap(NULL, NVRAM_SPACE, PROT_READ, MAP_SHARED, nvram_fd, 0)) == MAP_FAILED) {
  45                 close(nvram_fd);
  46                 nvram_fd = -1;
  47                 goto err;
  48         }
  49
  50         return 0;
  51
  52  err:
  53         perror(PATH_DEV_NVRAM);
  54         return errno;
  55 }
  56
  57 char *
  58 nvram_get(const char *name)
  59 {
  60         size_t count = strlen(name) + 1;
  61         char tmp[100], *value;
  62         unsigned long *off = (unsigned long *) tmp;
  63
  64         if (nvram_fd < 0)
  65                 if (nvram_init(NULL))
  66                         return NULL;
  67
  68         if (count > sizeof(tmp)) {
  69                 if (!(off = malloc(count)))
  70                         return NULL;
  71         }
  72
  73         /* Get offset into mmap() space */
  74         strcpy((char *) off, name);
  75
  76         count = read(nvram_fd, off, count);
  77
  78         if (count == sizeof(unsigned long))
  79                 value = &nvram_buf[*off];
  80         else
  81                 value = NULL;
  82
  83         if (count < 0)
  84                 perror(PATH_DEV_NVRAM);
  85
  86         if (off != (unsigned long *) tmp)
  87                 free(off);
  88
  89         return value;
  90 }
  91
  92 int
  93 nvram_getall(char *buf, int count)
  94 {
  95         int ret;
  96
  97         if (nvram_fd < 0)
  98                 if ((ret = nvram_init(NULL)))
  99                         return ret;
 100
 101         if (count == 0)
 102                 return 0;
 103
 104         /* Get all variables */
 105         *buf = '\0';
 106
 107         ret = read(nvram_fd, buf, count);
 108
 109         if (ret < 0)
 110                 perror(PATH_DEV_NVRAM);
 111
 112         return (ret == count) ? 0 : ret;
 113 }
 114
 115 int
 116 nvram_set(const char *name, const char *value)
 117 {
 118         size_t count = strlen(name) + 1;
 119         char tmp[100], *buf = tmp;
 120         int ret;
 121
 122         if (nvram_fd < 0)
 123                 if ((ret = nvram_init(NULL)))
 124                         return ret;
 125
 126         /* Unset if value is NULL */
 127         if (value)
 128                 count += strlen(value) + 1;
 129
 130         if (count > sizeof(tmp)) {
 131                 if (!(buf = malloc(count)))
 132                         return -ENOMEM;
 133         }
 134
 135         if (value)
 136                 sprintf(buf, "%s=%s", name, value);
 137         else
 138                 strcpy(buf, name);
 139
 140         ret = write(nvram_fd, buf, count);
 141
 142         if (ret < 0)
 143                 perror(PATH_DEV_NVRAM);
 144
 145         if (buf != tmp)
 146                 free(buf);
 147
 148         return (ret == count) ? 0 : ret;
 149 }
 150
 151 int
 152 nvram_unset(const char *name)
 153 {
 154         return nvram_set(name, NULL);
 155 }
 156
 157 int
 158 nvram_commit(void)
 159 {
 160         int ret;
 161
 162         if (nvram_fd < 0)
 163                 if ((ret = nvram_init(NULL)))
 164                         return ret;
 165
 166         ret = ioctl(nvram_fd, NVRAM_MAGIC, NULL);
 167
 168         if (ret < 0)
 169                 perror(PATH_DEV_NVRAM);
 170
 171         return ret;
 172 }
 173
 174 int
 175 file_to_buf(char *path, char *buf, int len)
 176 {
 177         FILE *fp;
 178
 179         memset(buf, 0 , len);
 180
 181         if ((fp = fopen(path, "r"))) {
 182                 fgets(buf, len, fp);
 183                 fclose(fp);
 184                 return 1;
 185         }
 186
 187         return 0;
 188 }