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/*
* Copyright (C) 2017 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 "VintfObjectRecovery.h"
#include <sys/mount.h>
#include <sys/stat.h>
#include <set>
#include <android-base/logging.h>
#include <android-base/strings.h>
#include <fs_mgr.h>
#include "utils.h"
namespace android {
namespace vintf {
namespace details {
using android::base::StartsWith;
using FstabMgr = std::unique_ptr<struct fstab, decltype(&fs_mgr_free_fstab)>;
static const char* const kMountImageRootDir = "/mnt";
static const char* const kSystemImageRootDir = "/mnt/system";
static status_t mountAt(const FstabMgr& fstab, const char* path, const char* mountPoint) {
mkdir(mountPoint, 0755); // in case it doesn't already exist
fstab_rec* rec = fs_mgr_get_entry_for_mount_point(fstab.get(), path);
if (rec == nullptr) {
LOG(WARNING) << "No mount point for " << path;
return NAME_NOT_FOUND;
}
int result = mount(rec->blk_device, mountPoint, rec->fs_type, rec->flags, rec->fs_options);
if (result != 0) {
PLOG(WARNING) << "Can't mount " << path;
}
return result == 0 ? OK : -errno;
}
static FstabMgr defaultFstabMgr() {
return FstabMgr{fs_mgr_read_fstab_default(), &fs_mgr_free_fstab};
}
class RecoveryPartitionMounter {
public:
RecoveryPartitionMounter() : fstab_(defaultFstabMgr()) {}
~RecoveryPartitionMounter() {
for (const auto& pair : mounted_) {
umount(pair.second.c_str());
}
mounted_.clear();
}
status_t mount(const std::string& path) {
if (path == "/system") {
if (!fstab_) return UNKNOWN_ERROR;
if (fs_mgr_get_entry_for_mount_point(fstab_.get(), "/system") == nullptr) {
return mount("/", kSystemImageRootDir);
} else {
return mount("/system", kSystemImageRootDir);
}
}
return mount(path, kMountImageRootDir + path);
}
private:
FstabMgr fstab_;
std::map<std::string, std::string> mounted_;
status_t mount(const std::string& path, const std::string& mountPoint) {
if (mounted_.find(path) != mounted_.end()) {
return OK;
}
if (!fstab_) return UNKNOWN_ERROR;
status_t status = mountAt(fstab_, path.c_str(), mountPoint.c_str());
if (status == OK) {
mounted_.emplace(path, mountPoint);
}
return status;
}
};
class RecoveryFileSystem : public FileSystem {
public:
RecoveryFileSystem() = default;
status_t fetch(const std::string& path, std::string* fetched, std::string* error) const {
const FileSystem* fs = nullptr;
status_t err = getFileSystem(path, &fs, error);
if (err != OK) return err;
return fs->fetch(path, fetched, error);
}
status_t listFiles(const std::string& path, std::vector<std::string>* out,
std::string* error) const {
const FileSystem* fs = nullptr;
status_t err = getFileSystem(path, &fs, error);
if (err != OK) return err;
return fs->listFiles(path, out, error);
}
private:
FileSystemUnderPath mSystemFileSystem{kSystemImageRootDir};
FileSystemUnderPath mMntFileSystem{kMountImageRootDir};
std::unique_ptr<RecoveryPartitionMounter> mMounter =
std::make_unique<RecoveryPartitionMounter>();
status_t getFileSystem(const std::string& path, const FileSystem** fs,
std::string* error) const {
auto partition = GetPartition(path);
if (partition.empty()) {
if (error) *error = "Cannot list or fetch relative path " + path;
return NAME_NOT_FOUND;
}
status_t err = mMounter->mount(partition);
if (err != OK) {
// in recovery, ignore mount errors and assume the file does not exist.
if (error) *error = "Cannot mount for path " + path + ": " + strerror(-err);
return NAME_NOT_FOUND;
}
// /system files are under /mnt/system/system because system.img contains the root dir.
if (partition == "/system") {
*fs = &mSystemFileSystem;
} else {
*fs = &mMntFileSystem;
}
return OK;
}
// /system -> /system
// /system/foo -> /system
static std::string GetPartition(const std::string& path) {
if (path.empty()) return "";
if (path[0] != '/') return "";
auto idx = path.find('/', 1);
if (idx == std::string::npos) return path;
return path.substr(0, idx);
}
};
} // namespace details
// static
int32_t VintfObjectRecovery::CheckCompatibility(const std::vector<std::string>& xmls,
std::string* error) {
auto vintfObject = VintfObject::Builder()
.setFileSystem(std::make_unique<details::RecoveryFileSystem>())
.build();
return vintfObject->checkCompatibility(xmls, error);
}
} // namespace vintf
} // namespace android