platform_bootable_recovery/fuse_sdcard_install.cpp

/*
 * 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.
 */

#include "fuse_sdcard_install.h"

#include <sys/mount.h>
#include <unistd.h>

#include <functional>
#include <memory>

#include "fuse_provider.h"
#include "fuse_sideload.h"

bool start_sdcard_fuse(const char* path) {
  auto file_data_reader = std::make_unique<FuseFileDataProvider>(path, 65536);

  if (!file_data_reader->Valid()) {
    return false;
  }

  // The installation process expects to find the sdcard unmounted. Unmount it with MNT_DETACH so
  // that our open file continues to work but new references see it as unmounted.
  umount2("/sdcard", MNT_DETACH);

  return run_fuse_sideload(std::move(file_data_reader)) == 0;
}