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  * $Id$
  13  */
  14
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <errno.h>
  19 #include <error.h>
  20 #include <string.h>
  21 #include <sys/ioctl.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <fcntl.h>
  25 #include <sys/mman.h>
  26
  27 #include <typedefs.h>
  28 #include <bcmnvram.h>
  29 #include <shutils.h>
  30
  31 #define PATH_DEV_NVRAM "/dev/nvram"
  32
  33 /* Globals */
  34 static int nvram_fd = -1;
  35 static char *nvram_buf = NULL;
  36 int file_to_buf(char *path, char *buf, int len);
  37
  38 int
  39 nvram_init(void *unused)
  40 {
  41         if ((nvram_fd = open(PATH_DEV_NVRAM, O_RDWR)) < 0)
  42                 goto err;
  43
  44         /* Map kernel string buffer into user space */
  45         if ((nvram_buf = mmap(NULL, NVRAM_SPACE, PROT_READ, MAP_SHARED, nvram_fd, 0)) == MAP_FAILED) {
  46                 close(nvram_fd);
  47                 nvram_fd = -1;
  48                 goto err;
  49         }
  50
  51         return 0;
  52
  53  err:
  54         perror(PATH_DEV_NVRAM);
  55         return errno;
  56 }
  57
  58 char *
  59 nvram_get(const char *name)
  60 {
  61         size_t count = strlen(name) + 1;
  62         char tmp[100], *value;
  63         unsigned long *off = (unsigned long *) tmp;
  64
  65         if (nvram_fd < 0)
  66                 if (nvram_init(NULL))
  67                         return NULL;
  68
  69         if (count > sizeof(tmp)) {
  70                 if (!(off = malloc(count)))
  71                         return NULL;
  72         }
  73
  74         /* Get offset into mmap() space */
  75         strcpy((char *) off, name);
  76
  77         count = read(nvram_fd, off, count);
  78
  79         if (count == sizeof(unsigned long))
  80                 value = &nvram_buf[*off];
  81         else
  82                 value = NULL;
  83
  84         if (count < 0)
  85                 perror(PATH_DEV_NVRAM);
  86
  87         if (off != (unsigned long *) tmp)
  88                 free(off);
  89
  90         return value;
  91 }
  92
  93 int
  94 nvram_getall(char *buf, int count)
  95 {
  96         int ret;
  97
  98         if (nvram_fd < 0)
  99                 if ((ret = nvram_init(NULL)))
 100                         return ret;
 101
 102         if (count == 0)
 103                 return 0;
 104
 105         /* Get all variables */
 106         *buf = '\0';
 107
 108         ret = read(nvram_fd, buf, count);
 109
 110         if (ret < 0)
 111                 perror(PATH_DEV_NVRAM);
 112
 113         return (ret == count) ? 0 : ret;
 114 }
 115
 116 int
 117 nvram_set(const char *name, const char *value)
 118 {
 119         size_t count = strlen(name) + 1;
 120         char tmp[100], *buf = tmp;
 121         int ret;
 122
 123         if (nvram_fd < 0)
 124                 if ((ret = nvram_init(NULL)))
 125                         return ret;
 126
 127         /* Unset if value is NULL */
 128         if (value)
 129                 count += strlen(value) + 1;
 130
 131         if (count > sizeof(tmp)) {
 132                 if (!(buf = malloc(count)))
 133                         return -ENOMEM;
 134         }
 135
 136         if (value)
 137                 sprintf(buf, "%s=%s", name, value);
 138         else
 139                 strcpy(buf, name);
 140
 141         ret = write(nvram_fd, buf, count);
 142
 143         if (ret < 0)
 144                 perror(PATH_DEV_NVRAM);
 145
 146         if (buf != tmp)
 147                 free(buf);
 148
 149         return (ret == count) ? 0 : ret;
 150 }
 151
 152 int
 153 nvram_unset(const char *name)
 154 {
 155         return nvram_set(name, NULL);
 156 }
 157
 158 int
 159 nvram_commit(void)
 160 {
 161         int ret;
 162
 163         if (nvram_fd < 0)
 164                 if ((ret = nvram_init(NULL)))
 165                         return ret;
 166
 167         ret = ioctl(nvram_fd, NVRAM_MAGIC, NULL);
 168
 169         if (ret < 0)
 170                 perror(PATH_DEV_NVRAM);
 171
 172         return ret;
 173 }
 174
 175 int
 176 file_to_buf(char *path, char *buf, int len)
 177 {
 178         FILE *fp;
 179
 180         memset(buf, 0 , len);
 181
 182         if ((fp = fopen(path, "r"))) {
 183                 fgets(buf, len, fp);
 184                 fclose(fp);
 185                 return 1;
 186         }
 187
 188         return 0;
 189 }