mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-28 01:28:59 +00:00
121 lines
1.8 KiB
C
121 lines
1.8 KiB
C
/*
|
|
* RouterBoot helper routines
|
|
*
|
|
* Copyright (C) 2012 Gabor Juhos <juhosg@openwrt.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published
|
|
* by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/routerboot.h>
|
|
|
|
#include "routerboot.h"
|
|
|
|
static u32 get_u32(void *buf)
|
|
{
|
|
u8 *p = buf;
|
|
|
|
return ((u32) p[3] + ((u32) p[2] << 8) + ((u32) p[1] << 16) +
|
|
((u32) p[0] << 24));
|
|
}
|
|
|
|
static u16 get_u16(void *buf)
|
|
{
|
|
u8 *p = buf;
|
|
|
|
return (u16) p[1] + ((u16) p[0] << 8);
|
|
}
|
|
|
|
__init int
|
|
routerboot_find_magic(u8 *buf, unsigned int buflen, u32 *offset, bool hard)
|
|
{
|
|
u32 magic_ref = hard ? RB_MAGIC_HARD : RB_MAGIC_SOFT;
|
|
u32 magic;
|
|
u32 cur = *offset;
|
|
|
|
while (cur < buflen) {
|
|
magic = get_u32(buf + cur);
|
|
if (magic == magic_ref) {
|
|
*offset = cur;
|
|
return 0;
|
|
}
|
|
|
|
cur += 0x1000;
|
|
}
|
|
|
|
return -ENOENT;
|
|
}
|
|
|
|
__init int
|
|
routerboot_find_tag(u8 *buf, unsigned int buflen, u16 tag_id,
|
|
u8 **tag_data, u16 *tag_len)
|
|
{
|
|
uint32_t magic;
|
|
int ret;
|
|
|
|
if (buflen < 4)
|
|
return -EINVAL;
|
|
|
|
magic = get_u32(buf);
|
|
switch (magic) {
|
|
case RB_MAGIC_HARD:
|
|
/* skip magic value */
|
|
buf += 4;
|
|
buflen -= 4;
|
|
break;
|
|
|
|
case RB_MAGIC_SOFT:
|
|
if (buflen < 8)
|
|
return -EINVAL;
|
|
|
|
/* skip magic and CRC value */
|
|
buf += 8;
|
|
buflen -= 8;
|
|
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = -ENOENT;
|
|
while (buflen > 2) {
|
|
u16 id;
|
|
u16 len;
|
|
|
|
len = get_u16(buf);
|
|
buf += 2;
|
|
buflen -= 2;
|
|
|
|
if (buflen < 2)
|
|
break;
|
|
|
|
id = get_u16(buf);
|
|
buf += 2;
|
|
buflen -= 2;
|
|
|
|
if (id == RB_ID_TERMINATOR)
|
|
break;
|
|
|
|
if (buflen < len)
|
|
break;
|
|
|
|
if (id == tag_id) {
|
|
if (tag_len)
|
|
*tag_len = len;
|
|
if (tag_data)
|
|
*tag_data = buf;
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
buf += len;
|
|
buflen -= len;
|
|
}
|
|
|
|
return ret;
|
|
}
|