openwrt/package/nvram/src/nvram.c

190 lines
3.1 KiB
C

/*
* NVRAM variable manipulation (Linux user mode half)
*
* Copyright 2004, Broadcom Corporation
* All Rights Reserved.
*
* THIS SOFTWARE IS OFFERED "AS IS", AND BROADCOM GRANTS NO WARRANTIES OF ANY
* KIND, EXPRESS OR IMPLIED, BY STATUTE, COMMUNICATION OR OTHERWISE. BROADCOM
* SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A SPECIFIC PURPOSE OR NONINFRINGEMENT CONCERNING THIS SOFTWARE.
*
* $Id$
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <error.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <typedefs.h>
#include <bcmnvram.h>
#include <shutils.h>
#define PATH_DEV_NVRAM "/dev/nvram"
/* Globals */
static int nvram_fd = -1;
static char *nvram_buf = NULL;
int file_to_buf(char *path, char *buf, int len);
int
nvram_init(void *unused)
{
if ((nvram_fd = open(PATH_DEV_NVRAM, O_RDWR)) < 0)
goto err;
/* Map kernel string buffer into user space */
if ((nvram_buf = mmap(NULL, NVRAM_SPACE, PROT_READ, MAP_SHARED, nvram_fd, 0)) == MAP_FAILED) {
close(nvram_fd);
nvram_fd = -1;
goto err;
}
return 0;
err:
perror(PATH_DEV_NVRAM);
return errno;
}
char *
nvram_get(const char *name)
{
size_t count = strlen(name) + 1;
char tmp[100], *value;
unsigned long *off = (unsigned long *) tmp;
if (nvram_fd < 0)
if (nvram_init(NULL))
return NULL;
if (count > sizeof(tmp)) {
if (!(off = malloc(count)))
return NULL;
}
/* Get offset into mmap() space */
strcpy((char *) off, name);
count = read(nvram_fd, off, count);
if (count == sizeof(unsigned long))
value = &nvram_buf[*off];
else
value = NULL;
if (count < 0)
perror(PATH_DEV_NVRAM);
if (off != (unsigned long *) tmp)
free(off);
return value;
}
int
nvram_getall(char *buf, int count)
{
int ret;
if (nvram_fd < 0)
if ((ret = nvram_init(NULL)))
return ret;
if (count == 0)
return 0;
/* Get all variables */
*buf = '\0';
ret = read(nvram_fd, buf, count);
if (ret < 0)
perror(PATH_DEV_NVRAM);
return (ret == count) ? 0 : ret;
}
int
nvram_set(const char *name, const char *value)
{
size_t count = strlen(name) + 1;
char tmp[100], *buf = tmp;
int ret;
if (nvram_fd < 0)
if ((ret = nvram_init(NULL)))
return ret;
/* Unset if value is NULL */
if (value)
count += strlen(value) + 1;
if (count > sizeof(tmp)) {
if (!(buf = malloc(count)))
return -ENOMEM;
}
if (value)
sprintf(buf, "%s=%s", name, value);
else
strcpy(buf, name);
ret = write(nvram_fd, buf, count);
if (ret < 0)
perror(PATH_DEV_NVRAM);
if (buf != tmp)
free(buf);
return (ret == count) ? 0 : ret;
}
int
nvram_unset(const char *name)
{
return nvram_set(name, NULL);
}
int
nvram_commit(void)
{
int ret;
if (nvram_fd < 0)
if ((ret = nvram_init(NULL)))
return ret;
ret = ioctl(nvram_fd, NVRAM_MAGIC, NULL);
if (ret < 0)
perror(PATH_DEV_NVRAM);
return ret;
}
int
file_to_buf(char *path, char *buf, int len)
{
FILE *fp;
memset(buf, 0 , len);
if ((fp = fopen(path, "r"))) {
fgets(buf, len, fp);
fclose(fp);
return 1;
}
return 0;
}