126 lines
4.0 KiB
C++
126 lines
4.0 KiB
C++
/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "utility.h"
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#include <android-base/logging.h>
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#include <fs_mgr_dm_linear.h>
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#include <liblp/liblp.h>
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#include "fastboot_device.h"
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using namespace android::fs_mgr;
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using android::base::unique_fd;
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using android::hardware::boot::V1_0::Slot;
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static bool OpenPhysicalPartition(const std::string& name, PartitionHandle* handle) {
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std::optional<std::string> path = FindPhysicalPartition(name);
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if (!path) {
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return false;
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}
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*handle = PartitionHandle(*path);
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return true;
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}
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static bool OpenLogicalPartition(const std::string& name, const std::string& slot,
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PartitionHandle* handle) {
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std::optional<std::string> path = FindPhysicalPartition(LP_METADATA_PARTITION_NAME);
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if (!path) {
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return false;
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}
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uint32_t slot_number = SlotNumberForSlotSuffix(slot);
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std::string dm_path;
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if (!CreateLogicalPartition(path->c_str(), slot_number, name, true, &dm_path)) {
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LOG(ERROR) << "Could not map partition: " << name;
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return false;
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}
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auto closer = [name]() -> void { DestroyLogicalPartition(name); };
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*handle = PartitionHandle(dm_path, std::move(closer));
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return true;
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}
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bool OpenPartition(FastbootDevice* device, const std::string& name, PartitionHandle* handle) {
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// We prioritize logical partitions over physical ones, and do this
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// consistently for other partition operations (like getvar:partition-size).
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if (LogicalPartitionExists(name, device->GetCurrentSlot())) {
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if (!OpenLogicalPartition(name, device->GetCurrentSlot(), handle)) {
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return false;
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}
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} else if (!OpenPhysicalPartition(name, handle)) {
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LOG(ERROR) << "No such partition: " << name;
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return false;
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}
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unique_fd fd(TEMP_FAILURE_RETRY(open(handle->path().c_str(), O_WRONLY | O_EXCL)));
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if (fd < 0) {
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PLOG(ERROR) << "Failed to open block device: " << handle->path();
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return false;
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}
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handle->set_fd(std::move(fd));
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return true;
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}
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std::optional<std::string> FindPhysicalPartition(const std::string& name) {
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std::string path = "/dev/block/by-name/" + name;
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if (access(path.c_str(), R_OK | W_OK) < 0) {
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return {};
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}
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return path;
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}
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static const LpMetadataPartition* FindLogicalPartition(const LpMetadata& metadata,
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const std::string& name) {
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for (const auto& partition : metadata.partitions) {
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if (GetPartitionName(partition) == name) {
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return &partition;
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}
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}
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return nullptr;
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}
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bool LogicalPartitionExists(const std::string& name, const std::string& slot_suffix,
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bool* is_zero_length) {
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auto path = FindPhysicalPartition(LP_METADATA_PARTITION_NAME);
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if (!path) {
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return false;
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}
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uint32_t slot_number = SlotNumberForSlotSuffix(slot_suffix);
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std::unique_ptr<LpMetadata> metadata = ReadMetadata(path->c_str(), slot_number);
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if (!metadata) {
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return false;
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}
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const LpMetadataPartition* partition = FindLogicalPartition(*metadata.get(), name);
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if (!partition) {
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return false;
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}
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if (is_zero_length) {
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*is_zero_length = (partition->num_extents == 0);
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}
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return true;
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}
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bool GetSlotNumber(const std::string& slot, Slot* number) {
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if (slot.size() != 1) {
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return false;
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}
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if (slot[0] < 'a' || slot[0] > 'z') {
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return false;
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}
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*number = slot[0] - 'a';
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return true;
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}
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