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/*
* Copyright (C) 2019 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.
*/
#define LOG_TAG "bootcontrolhal"
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
#include <bootloader_message/bootloader_message.h>
#include "BootControlShared.h"
namespace android {
namespace hardware {
namespace boot {
namespace V1_1 {
namespace implementation {
using android::base::unique_fd;
using android::hardware::boot::V1_1::MergeStatus;
constexpr off_t kBootloaderControlOffset = offsetof(bootloader_message_ab, slot_suffix);
static uint32_t CRC32(const uint8_t *buf, size_t size) {
static uint32_t crc_table[256];
// Compute the CRC-32 table only once.
if (!crc_table[1]) {
for (uint32_t i = 0; i < 256; ++i) {
uint32_t crc = i;
for (uint32_t j = 0; j < 8; ++j) {
uint32_t mask = -(crc & 1);
crc = (crc >> 1) ^ (0xEDB88320 & mask);
}
crc_table[i] = crc;
}
}
uint32_t ret = -1;
for (size_t i = 0; i < size; ++i) {
ret = (ret >> 8) ^ crc_table[(ret ^ buf[i]) & 0xFF];
}
return ~ret;
}
uint32_t ComputeChecksum(const bootloader_control *boot_ctrl) {
return CRC32(reinterpret_cast<const uint8_t *>(boot_ctrl),
offsetof(bootloader_control, crc32_le));
}
static bool LoadUpdateState(const std::string &misc_device, bootloader_control *buffer) {
unique_fd fd(open(misc_device.c_str(), O_RDONLY));
if (fd < 0) {
PLOG(ERROR) << "failed to open " << misc_device;
return false;
}
if (lseek(fd, kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) {
PLOG(ERROR) << "failed to lseek " << misc_device;
return false;
}
if (!android::base::ReadFully(fd, buffer, sizeof(bootloader_control))) {
PLOG(ERROR) << "failed to read " << misc_device;
return false;
}
return true;
}
static bool SaveUpdateState(const std::string &misc_device, bootloader_control *buffer) {
unique_fd fd(open(misc_device.c_str(), O_WRONLY | O_SYNC));
if (fd < 0) {
PLOG(ERROR) << "failed to open " << misc_device;
return false;
}
if (lseek(fd, kBootloaderControlOffset, SEEK_SET) != kBootloaderControlOffset) {
PLOG(ERROR) << "failed to lseek " << misc_device;
return false;
}
buffer->crc32_le = ComputeChecksum(buffer);
if (!android::base::WriteFully(fd, buffer, sizeof(bootloader_control))) {
PLOG(ERROR) << "failed to write " << misc_device;
return false;
}
return true;
}
BootControlShared::BootControlShared() {
std::string err;
misc_device_ = get_bootloader_message_blk_device(&err);
if (misc_device_.empty()) {
LOG(FATAL) << "Unable to locate misc device: " << err;
}
bootloader_control control;
if (!LoadUpdateState(misc_device_, &control)) {
LOG(FATAL) << "Unable to read update state from misc partition";
}
uint32_t computed_crc32 = ComputeChecksum(&control);
bool initialize = false;
if (computed_crc32 != control.crc32_le) {
LOG(WARNING) << "Invalid boot control found, expected CRC32 0x" << std::hex
<< computed_crc32 << " but found 0x" << std::hex << control.crc32_le;
initialize = true;
} else if (control.magic != BOOT_CTRL_MAGIC) {
LOG(WARNING) << "Invalid boot control magic, " << std::hex << control.magic;
initialize = true;
}
if (initialize) {
LOG(WARNING) << "Re-initializing misc.";
// We only use the |merge_status| field of this structure.
memset(&control, 0, sizeof(control));
control.magic = BOOT_CTRL_MAGIC;
control.version = BOOT_CTRL_VERSION;
control.merge_status = static_cast<uint8_t>(MergeStatus::NONE);
SaveUpdateState(misc_device_, &control);
}
}
Return<bool> BootControlShared::setSnapshotMergeStatus(MergeStatus status) {
bootloader_control control;
if (!LoadUpdateState(misc_device_, &control)) {
return false;
}
control.merge_status = static_cast<uint8_t>(status);
return SaveUpdateState(misc_device_, &control);
}
Return<MergeStatus> BootControlShared::getSnapshotMergeStatus() {
bootloader_control control;
if (!LoadUpdateState(misc_device_, &control)) {
return MergeStatus::UNKNOWN;
}
return static_cast<MergeStatus>(control.merge_status);
}
} // namespace implementation
} // namespace V1_1
} // namespace boot
} // namespace hardware
} // namespace android
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