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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 <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;
}
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