| /* |
| * 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 <string> |
| |
| #include <android-base/file.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| #include <android-base/properties.h> |
| |
| #include "fs_mgr_priv.h" |
| |
| // Tries to get the given boot config value from kernel cmdline. |
| // Returns true if successfully found, false otherwise. |
| bool fs_mgr_get_boot_config_from_kernel_cmdline(const std::string& key, std::string* out_val) { |
| FS_MGR_CHECK(out_val != nullptr); |
| |
| std::string cmdline; |
| std::string cmdline_key("androidboot." + key); |
| if (android::base::ReadFileToString("/proc/cmdline", &cmdline)) { |
| for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) { |
| std::vector<std::string> pieces = android::base::Split(entry, "="); |
| if (pieces.size() == 2) { |
| if (pieces[0] == cmdline_key) { |
| *out_val = pieces[1]; |
| return true; |
| } |
| } |
| } |
| } |
| |
| return false; |
| } |
| |
| // Tries to get the boot config value in properties, kernel cmdline and |
| // device tree (in that order). returns 'true' if successfully found, 'false' |
| // otherwise |
| bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) { |
| FS_MGR_CHECK(out_val != nullptr); |
| |
| // first check if we have "ro.boot" property already |
| *out_val = android::base::GetProperty("ro.boot." + key, ""); |
| if (!out_val->empty()) { |
| return true; |
| } |
| |
| // fallback to kernel cmdline, properties may not be ready yet |
| if (fs_mgr_get_boot_config_from_kernel_cmdline(key, out_val)) { |
| return true; |
| } |
| |
| // lastly, check the device tree |
| if (is_dt_compatible()) { |
| std::string file_name = get_android_dt_dir() + "/" + key; |
| if (android::base::ReadFileToString(file_name, out_val)) { |
| if (!out_val->empty()) { |
| out_val->pop_back(); // Trims the trailing '\0' out. |
| return true; |
| } |
| } |
| } |
| |
| return false; |
| } |