You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
119 lines
3.5 KiB
119 lines
3.5 KiB
/*
|
|
* Copyright (C) 2021 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "libxbc.h"
|
|
|
|
#define BOOTCONFIG_MAGIC "#BOOTCONFIG\n"
|
|
#define BOOTCONFIG_MAGIC_SIZE 12
|
|
#define BOOTCONFIG_SIZE_SIZE 4
|
|
#define BOOTCONFIG_CHECKSUM_SIZE 4
|
|
#define BOOTCONFIG_TRAILER_SIZE BOOTCONFIG_MAGIC_SIZE + \
|
|
BOOTCONFIG_SIZE_SIZE + \
|
|
BOOTCONFIG_CHECKSUM_SIZE
|
|
/*
|
|
* Simple checksum for a buffer.
|
|
*
|
|
* @param addr pointer to the start of the buffer.
|
|
* @param size size of the buffer in bytes.
|
|
* @return check sum result.
|
|
*/
|
|
static uint32_t checksum(const unsigned char* const buffer, uint32_t size) {
|
|
uint32_t sum = 0;
|
|
for (uint32_t i = 0; i < size; i++) {
|
|
sum += buffer[i];
|
|
}
|
|
return sum;
|
|
}
|
|
|
|
/*
|
|
* Check if the bootconfig trailer is present within the bootconfig section.
|
|
*
|
|
* @param bootconfig_end_addr address of the end of the bootconfig section. If
|
|
* the trailer is present, it will be directly preceding this address.
|
|
* @return true if the trailer is present, false if not.
|
|
*/
|
|
static bool isTrailerPresent(uint64_t bootconfig_end_addr) {
|
|
return !strncmp((char*)(bootconfig_end_addr - BOOTCONFIG_MAGIC_SIZE),
|
|
BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_SIZE);
|
|
}
|
|
|
|
/*
|
|
* Add a string of boot config parameters to memory appended by the trailer.
|
|
*/
|
|
int32_t addBootConfigParameters(char* params, uint32_t params_size,
|
|
uint64_t bootconfig_start_addr, uint32_t bootconfig_size) {
|
|
if (!params || !bootconfig_start_addr) {
|
|
return -1;
|
|
}
|
|
if (params_size == 0) {
|
|
return 0;
|
|
}
|
|
int32_t applied_bytes = 0;
|
|
int32_t new_size = 0;
|
|
uint64_t end = bootconfig_start_addr + bootconfig_size;
|
|
|
|
if (isTrailerPresent(end)) {
|
|
end -= BOOTCONFIG_TRAILER_SIZE;
|
|
applied_bytes -= BOOTCONFIG_TRAILER_SIZE;
|
|
memcpy(&new_size, (void *)end, BOOTCONFIG_SIZE_SIZE);
|
|
} else {
|
|
new_size = bootconfig_size;
|
|
}
|
|
|
|
// params
|
|
memcpy((void*)end, params, params_size);
|
|
|
|
applied_bytes += params_size;
|
|
applied_bytes += addBootConfigTrailer(bootconfig_start_addr,
|
|
bootconfig_size + applied_bytes);
|
|
|
|
return applied_bytes;
|
|
}
|
|
|
|
/*
|
|
* Add boot config trailer.
|
|
*/
|
|
int32_t addBootConfigTrailer(uint64_t bootconfig_start_addr,
|
|
uint32_t bootconfig_size) {
|
|
if (!bootconfig_start_addr) {
|
|
return -1;
|
|
}
|
|
if (bootconfig_size == 0) {
|
|
return 0;
|
|
}
|
|
uint64_t end = bootconfig_start_addr + bootconfig_size;
|
|
|
|
if (isTrailerPresent(end)) {
|
|
// no need to overwrite the current trailers
|
|
return 0;
|
|
}
|
|
|
|
// size
|
|
memcpy((void *)(end), &bootconfig_size, BOOTCONFIG_SIZE_SIZE);
|
|
|
|
// checksum
|
|
uint32_t sum =
|
|
checksum((unsigned char*)bootconfig_start_addr, bootconfig_size);
|
|
memcpy((void *)(end + BOOTCONFIG_SIZE_SIZE), &sum,
|
|
BOOTCONFIG_CHECKSUM_SIZE);
|
|
|
|
// magic
|
|
memcpy((void *)(end + BOOTCONFIG_SIZE_SIZE + BOOTCONFIG_CHECKSUM_SIZE),
|
|
BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_SIZE);
|
|
|
|
return BOOTCONFIG_TRAILER_SIZE;
|
|
}
|