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/*
* vpd_decode.c
*
* Google VPD decoding routines.
*
* Copyright 2017 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2.0 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/export.h>
#include "vpd_decode.h"
static int vpd_decode_len(const s32 max_len, const u8 *in,
s32 *length, s32 *decoded_len)
{
u8 more;
int i = 0;
if (!length || !decoded_len)
return VPD_FAIL;
*length = 0;
do {
if (i >= max_len)
return VPD_FAIL;
more = in[i] & 0x80;
*length <<= 7;
*length |= in[i] & 0x7f;
++i;
} while (more);
*decoded_len = i;
return VPD_OK;
}
int vpd_decode_string(const s32 max_len, const u8 *input_buf, s32 *consumed,
vpd_decode_callback callback, void *callback_arg)
{
int type;
int res;
s32 key_len;
s32 value_len;
s32 decoded_len;
const u8 *key;
const u8 *value;
/* type */
if (*consumed >= max_len)
return VPD_FAIL;
type = input_buf[*consumed];
switch (type) {
case VPD_TYPE_INFO:
case VPD_TYPE_STRING:
(*consumed)++;
/* key */
res = vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
&key_len, &decoded_len);
if (res != VPD_OK || *consumed + decoded_len >= max_len)
return VPD_FAIL;
*consumed += decoded_len;
key = &input_buf[*consumed];
*consumed += key_len;
/* value */
res = vpd_decode_len(max_len - *consumed, &input_buf[*consumed],
&value_len, &decoded_len);
if (res != VPD_OK || *consumed + decoded_len > max_len)
return VPD_FAIL;
*consumed += decoded_len;
value = &input_buf[*consumed];
*consumed += value_len;
if (type == VPD_TYPE_STRING)
return callback(key, key_len, value, value_len,
callback_arg);
break;
default:
return VPD_FAIL;
}
return VPD_OK;
}
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