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/*
* Copyright (C) 2018 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.
*/
#ifndef ANDROID_APEXD_APEX_DATABASE_H_
#define ANDROID_APEXD_APEX_DATABASE_H_
#include <map>
#include <string>
#include <unordered_set>
#include <android-base/logging.h>
namespace android {
namespace apex {
class MountedApexDatabase {
public:
// Stores associated low-level data for a mounted APEX. To conserve memory,
// the APEX file isn't stored, but must be opened to retrieve specific data.
struct MountedApexData {
std::string loop_name; // Loop device used (fs path).
std::string full_path; // Full path to the apex file.
std::string mount_point; // Path this apex is mounted on.
std::string device_name; // Name of the dm verity device.
// Name of the loop device backing up hashtree or empty string in case
// hashtree is embedded inside an APEX.
std::string hashtree_loop_name;
MountedApexData() {}
MountedApexData(const std::string& loop_name, const std::string& full_path,
const std::string& mount_point,
const std::string& device_name,
const std::string& hashtree_loop_name)
: loop_name(loop_name),
full_path(full_path),
mount_point(mount_point),
device_name(device_name),
hashtree_loop_name(hashtree_loop_name) {}
inline bool operator<(const MountedApexData& rhs) const {
int compare_val = loop_name.compare(rhs.loop_name);
if (compare_val < 0) {
return true;
} else if (compare_val > 0) {
return false;
}
compare_val = full_path.compare(rhs.full_path);
if (compare_val < 0) {
return true;
} else if (compare_val > 0) {
return false;
}
compare_val = mount_point.compare(rhs.mount_point);
if (compare_val < 0) {
return true;
} else if (compare_val > 0) {
return false;
}
compare_val = device_name.compare(rhs.device_name);
if (compare_val < 0) {
return true;
} else if (compare_val > 0) {
return false;
}
return hashtree_loop_name < rhs.hashtree_loop_name;
}
};
inline void CheckAtMostOneLatest() {
for (const auto& apex_set : mounted_apexes_) {
size_t count = 0;
for (const auto& pair : apex_set.second) {
if (pair.second) {
count++;
}
}
CHECK_LE(count, 1u) << apex_set.first;
}
}
inline void CheckUniqueLoopDm() {
std::unordered_set<std::string> loop_devices;
std::unordered_set<std::string> dm_devices;
for (const auto& apex_set : mounted_apexes_) {
for (const auto& pair : apex_set.second) {
if (pair.first.loop_name != "") {
CHECK(loop_devices.insert(pair.first.loop_name).second)
<< "Duplicate loop device: " << pair.first.loop_name;
}
if (pair.first.device_name != "") {
CHECK(dm_devices.insert(pair.first.device_name).second)
<< "Duplicate dm device: " << pair.first.device_name;
}
if (pair.first.hashtree_loop_name != "") {
CHECK(loop_devices.insert(pair.first.hashtree_loop_name).second)
<< "Duplicate loop device: " << pair.first.hashtree_loop_name;
}
}
}
}
template <typename... Args>
inline void AddMountedApex(const std::string& package, bool latest,
Args&&... args) {
auto it = mounted_apexes_.find(package);
if (it == mounted_apexes_.end()) {
auto insert_it =
mounted_apexes_.emplace(package, std::map<MountedApexData, bool>());
CHECK(insert_it.second);
it = insert_it.first;
}
auto check_it = it->second.emplace(
MountedApexData(std::forward<Args>(args)...), latest);
CHECK(check_it.second);
CheckAtMostOneLatest();
CheckUniqueLoopDm();
}
inline void RemoveMountedApex(const std::string& package,
const std::string& full_path) {
auto it = mounted_apexes_.find(package);
if (it == mounted_apexes_.end()) {
return;
}
auto& pkg_map = it->second;
for (auto pkg_it = pkg_map.begin(); pkg_it != pkg_map.end(); ++pkg_it) {
if (pkg_it->first.full_path == full_path) {
pkg_map.erase(pkg_it);
return;
}
}
}
inline void SetLatest(const std::string& package,
const std::string& full_path) {
auto it = mounted_apexes_.find(package);
CHECK(it != mounted_apexes_.end());
auto& pkg_map = it->second;
for (auto pkg_it = pkg_map.begin(); pkg_it != pkg_map.end(); ++pkg_it) {
if (pkg_it->first.full_path == full_path) {
pkg_it->second = true;
for (auto reset_it = pkg_map.begin(); reset_it != pkg_map.end();
++reset_it) {
if (reset_it != pkg_it) {
reset_it->second = false;
}
}
return;
}
}
LOG(FATAL) << "Did not find " << package << " " << full_path;
}
inline void UnsetLatestForall(const std::string& package) {
auto it = mounted_apexes_.find(package);
if (it == mounted_apexes_.end()) {
return;
}
for (auto& data : it->second) {
data.second = false;
}
}
template <typename T>
inline void ForallMountedApexes(const std::string& package,
const T& handler) const {
auto it = mounted_apexes_.find(package);
if (it == mounted_apexes_.end()) {
return;
}
for (auto& pair : it->second) {
handler(pair.first, pair.second);
}
}
template <typename T>
inline void ForallMountedApexes(const T& handler) const {
for (const auto& pkg : mounted_apexes_) {
for (const auto& pair : pkg.second) {
handler(pkg.first, pair.first, pair.second);
}
}
}
void PopulateFromMounts();
private:
// A map from package name to mounted apexes.
// Note: using std::maps to
// a) so we do not have to worry about iterator invalidation.
// b) do not have to const_cast (over std::set)
// TODO: Eventually this structure (and functions) need to be guarded by
// locks.
std::map<std::string, std::map<MountedApexData, bool>> mounted_apexes_;
};
} // namespace apex
} // namespace android
#endif // ANDROID_APEXD_APEX_DATABASE_H_
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