124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
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#include "android-base/properties.h"
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#include <sys/system_properties.h>
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#include <sys/_system_properties.h>
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#include <string>
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#include <android-base/parseint.h>
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namespace android {
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namespace base {
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std::string GetProperty(const std::string& key, const std::string& default_value) {
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const prop_info* pi = __system_property_find(key.c_str());
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if (pi == nullptr) return default_value;
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char buf[PROP_VALUE_MAX];
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if (__system_property_read(pi, nullptr, buf) > 0) return buf;
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// If the property exists but is empty, also return the default value.
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// Since we can't remove system properties, "empty" is traditionally
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// the same as "missing" (this was true for cutils' property_get).
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return default_value;
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}
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bool GetBoolProperty(const std::string& key, bool default_value) {
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std::string value = GetProperty(key, "");
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if (value == "1" || value == "y" || value == "yes" || value == "on" || value == "true") {
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return true;
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} else if (value == "0" || value == "n" || value == "no" || value == "off" || value == "false") {
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return false;
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}
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return default_value;
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}
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template <typename T>
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T GetIntProperty(const std::string& key, T default_value, T min, T max) {
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T result;
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std::string value = GetProperty(key, "");
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if (!value.empty() && android::base::ParseInt(value, &result, min, max)) return result;
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return default_value;
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}
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template <typename T>
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T GetUintProperty(const std::string& key, T default_value, T max) {
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T result;
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std::string value = GetProperty(key, "");
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if (!value.empty() && android::base::ParseUint(value, &result, max)) return result;
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return default_value;
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}
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template int8_t GetIntProperty(const std::string&, int8_t, int8_t, int8_t);
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template int16_t GetIntProperty(const std::string&, int16_t, int16_t, int16_t);
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template int32_t GetIntProperty(const std::string&, int32_t, int32_t, int32_t);
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template int64_t GetIntProperty(const std::string&, int64_t, int64_t, int64_t);
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template uint8_t GetUintProperty(const std::string&, uint8_t, uint8_t);
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template uint16_t GetUintProperty(const std::string&, uint16_t, uint16_t);
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template uint32_t GetUintProperty(const std::string&, uint32_t, uint32_t);
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template uint64_t GetUintProperty(const std::string&, uint64_t, uint64_t);
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bool SetProperty(const std::string& key, const std::string& value) {
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return (__system_property_set(key.c_str(), value.c_str()) == 0);
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}
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struct WaitForPropertyData {
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bool done;
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const std::string* expected_value;
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unsigned last_read_serial;
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};
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static void WaitForPropertyCallback(void* data_ptr, const char*, const char* value, unsigned serial) {
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WaitForPropertyData* data = reinterpret_cast<WaitForPropertyData*>(data_ptr);
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if (*data->expected_value == value) {
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data->done = true;
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} else {
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data->last_read_serial = serial;
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}
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}
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void WaitForProperty(const std::string& key, const std::string& expected_value) {
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// Find the property's prop_info*.
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const prop_info* pi;
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unsigned global_serial = 0;
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while ((pi = __system_property_find(key.c_str())) == nullptr) {
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// The property doesn't even exist yet.
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// Wait for a global change and then look again.
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global_serial = __system_property_wait_any(global_serial);
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}
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WaitForPropertyData data;
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data.expected_value = &expected_value;
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data.done = false;
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while (true) {
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// Check whether the property has the value we're looking for?
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__system_property_read_callback(pi, WaitForPropertyCallback, &data);
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if (data.done) return;
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// It didn't so wait for it to change before checking again.
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__system_property_wait(pi, data.last_read_serial);
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}
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}
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} // namespace base
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} // namespace android
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