| /* //device/libs/android_runtime/android_os_SystemProperties.cpp |
| ** |
| ** Copyright 2006, 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. |
| */ |
| |
| #define LOG_TAG "SysPropJNI" |
| |
| #include <utility> |
| #include <optional> |
| |
| #include "android-base/logging.h" |
| #include "android-base/parsebool.h" |
| #include "android-base/parseint.h" |
| #include "android-base/properties.h" |
| #include "utils/misc.h" |
| #include <utils/Log.h> |
| #include "jni.h" |
| #include "core_jni_helpers.h" |
| #include <nativehelper/JNIHelp.h> |
| #include <nativehelper/ScopedPrimitiveArray.h> |
| #include <nativehelper/ScopedUtfChars.h> |
| |
| #if defined(__BIONIC__) |
| # include <sys/system_properties.h> |
| #else |
| struct prop_info; |
| #endif |
| |
| namespace android { |
| namespace { |
| |
| using android::base::ParseBoolResult; |
| |
| template<typename Functor> |
| void ReadProperty(const prop_info* prop, Functor&& functor) |
| { |
| #if defined(__BIONIC__) |
| auto thunk = [](void* cookie, |
| const char* /*name*/, |
| const char* value, |
| uint32_t /*serial*/) { |
| std::forward<Functor>(*static_cast<Functor*>(cookie))(value); |
| }; |
| __system_property_read_callback(prop, thunk, &functor); |
| #else |
| LOG(FATAL) << "fast property access supported only on device"; |
| #endif |
| } |
| |
| template<typename Functor> |
| void ReadProperty(JNIEnv* env, jstring keyJ, Functor&& functor) |
| { |
| ScopedUtfChars key(env, keyJ); |
| if (!key.c_str()) { |
| return; |
| } |
| #if defined(__BIONIC__) |
| const prop_info* prop = __system_property_find(key.c_str()); |
| if (!prop) { |
| return; |
| } |
| ReadProperty(prop, std::forward<Functor>(functor)); |
| #else |
| std::forward<Functor>(functor)( |
| android::base::GetProperty(key.c_str(), "").c_str()); |
| #endif |
| } |
| |
| jstring SystemProperties_getSS(JNIEnv* env, jclass clazz, jstring keyJ, |
| jstring defJ) |
| { |
| jstring ret = defJ; |
| ReadProperty(env, keyJ, [&](const char* value) { |
| if (value[0]) { |
| ret = env->NewStringUTF(value); |
| } |
| }); |
| if (ret == nullptr && !env->ExceptionCheck()) { |
| ret = env->NewStringUTF(""); // Legacy behavior |
| } |
| return ret; |
| } |
| |
| template <typename T> |
| T SystemProperties_get_integral(JNIEnv *env, jclass, jstring keyJ, |
| T defJ) |
| { |
| T ret = defJ; |
| ReadProperty(env, keyJ, [&](const char* value) { |
| android::base::ParseInt<T>(value, &ret); |
| }); |
| return ret; |
| } |
| |
| static jboolean jbooleanFromParseBoolResult(ParseBoolResult parseResult, jboolean defJ) { |
| jboolean ret; |
| switch (parseResult) { |
| case ParseBoolResult::kError: |
| ret = defJ; |
| break; |
| case ParseBoolResult::kFalse: |
| ret = JNI_FALSE; |
| break; |
| case ParseBoolResult::kTrue: |
| ret = JNI_TRUE; |
| break; |
| } |
| return ret; |
| } |
| |
| jboolean SystemProperties_get_boolean(JNIEnv *env, jclass, jstring keyJ, |
| jboolean defJ) |
| { |
| ParseBoolResult parseResult = ParseBoolResult::kError; |
| ReadProperty(env, keyJ, [&](const char* value) { |
| parseResult = android::base::ParseBool(value); |
| }); |
| return jbooleanFromParseBoolResult(parseResult, defJ); |
| } |
| |
| jlong SystemProperties_find(JNIEnv* env, jclass, jstring keyJ) |
| { |
| #if defined(__BIONIC__) |
| ScopedUtfChars key(env, keyJ); |
| if (!key.c_str()) { |
| return 0; |
| } |
| const prop_info* prop = __system_property_find(key.c_str()); |
| return reinterpret_cast<jlong>(prop); |
| #else |
| LOG(FATAL) << "fast property access supported only on device"; |
| __builtin_unreachable(); // Silence warning |
| #endif |
| } |
| |
| jstring SystemProperties_getH(JNIEnv* env, jclass clazz, jlong propJ) |
| { |
| jstring ret; |
| auto prop = reinterpret_cast<const prop_info*>(propJ); |
| ReadProperty(prop, [&](const char* value) { |
| ret = env->NewStringUTF(value); |
| }); |
| return ret; |
| } |
| |
| template <typename T> |
| T SystemProperties_get_integralH(CRITICAL_JNI_PARAMS_COMMA jlong propJ, T defJ) |
| { |
| T ret = defJ; |
| auto prop = reinterpret_cast<const prop_info*>(propJ); |
| ReadProperty(prop, [&](const char* value) { |
| android::base::ParseInt<T>(value, &ret); |
| }); |
| return ret; |
| } |
| |
| jboolean SystemProperties_get_booleanH(CRITICAL_JNI_PARAMS_COMMA jlong propJ, jboolean defJ) |
| { |
| ParseBoolResult parseResult = ParseBoolResult::kError; |
| auto prop = reinterpret_cast<const prop_info*>(propJ); |
| ReadProperty(prop, [&](const char* value) { |
| parseResult = android::base::ParseBool(value); |
| }); |
| return jbooleanFromParseBoolResult(parseResult, defJ); |
| } |
| |
| void SystemProperties_set(JNIEnv *env, jobject clazz, jstring keyJ, |
| jstring valJ) |
| { |
| ScopedUtfChars key(env, keyJ); |
| if (!key.c_str()) { |
| return; |
| } |
| std::optional<ScopedUtfChars> value; |
| if (valJ != nullptr) { |
| value.emplace(env, valJ); |
| if (!value->c_str()) { |
| return; |
| } |
| } |
| bool success; |
| #if defined(__BIONIC__) |
| success = !__system_property_set(key.c_str(), value ? value->c_str() : ""); |
| #else |
| success = android::base::SetProperty(key.c_str(), value ? value->c_str() : ""); |
| #endif |
| if (!success) { |
| jniThrowException(env, "java/lang/RuntimeException", |
| "failed to set system property (check logcat for reason)"); |
| } |
| } |
| |
| JavaVM* sVM = nullptr; |
| jclass sClazz = nullptr; |
| jmethodID sCallChangeCallbacks; |
| |
| void do_report_sysprop_change() { |
| //ALOGI("Java SystemProperties: VM=%p, Clazz=%p", sVM, sClazz); |
| if (sVM != nullptr && sClazz != nullptr) { |
| JNIEnv* env; |
| if (sVM->GetEnv((void **)&env, JNI_VERSION_1_4) >= 0) { |
| //ALOGI("Java SystemProperties: calling %p", sCallChangeCallbacks); |
| env->CallStaticVoidMethod(sClazz, sCallChangeCallbacks); |
| // There should not be any exceptions. But we must guarantee |
| // there are none on return. |
| if (env->ExceptionCheck()) { |
| env->ExceptionClear(); |
| LOG(ERROR) << "Exception pending after sysprop_change!"; |
| } |
| } |
| } |
| } |
| |
| void SystemProperties_add_change_callback(JNIEnv *env, jobject clazz) |
| { |
| // This is called with the Java lock held. |
| if (sVM == nullptr) { |
| env->GetJavaVM(&sVM); |
| } |
| if (sClazz == nullptr) { |
| sClazz = (jclass) env->NewGlobalRef(clazz); |
| sCallChangeCallbacks = env->GetStaticMethodID(sClazz, "callChangeCallbacks", "()V"); |
| add_sysprop_change_callback(do_report_sysprop_change, -10000); |
| } |
| } |
| |
| void SystemProperties_report_sysprop_change(JNIEnv /**env*/, jobject /*clazz*/) |
| { |
| report_sysprop_change(); |
| } |
| |
| } // namespace |
| |
| int register_android_os_SystemProperties(JNIEnv *env) |
| { |
| const JNINativeMethod method_table[] = { |
| { "native_get", |
| "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;", |
| (void*) SystemProperties_getSS }, |
| { "native_get_int", "(Ljava/lang/String;I)I", |
| (void*) SystemProperties_get_integral<jint> }, |
| { "native_get_long", "(Ljava/lang/String;J)J", |
| (void*) SystemProperties_get_integral<jlong> }, |
| { "native_get_boolean", "(Ljava/lang/String;Z)Z", |
| (void*) SystemProperties_get_boolean }, |
| { "native_find", |
| "(Ljava/lang/String;)J", |
| (void*) SystemProperties_find }, |
| { "native_get", |
| "(J)Ljava/lang/String;", |
| (void*) SystemProperties_getH }, |
| { "native_get_int", "(JI)I", |
| (void*) SystemProperties_get_integralH<jint> }, |
| { "native_get_long", "(JJ)J", |
| (void*) SystemProperties_get_integralH<jlong> }, |
| { "native_get_boolean", "(JZ)Z", |
| (void*) SystemProperties_get_booleanH }, |
| { "native_set", "(Ljava/lang/String;Ljava/lang/String;)V", |
| (void*) SystemProperties_set }, |
| { "native_add_change_callback", "()V", |
| (void*) SystemProperties_add_change_callback }, |
| { "native_report_sysprop_change", "()V", |
| (void*) SystemProperties_report_sysprop_change }, |
| }; |
| return RegisterMethodsOrDie(env, "android/os/SystemProperties", |
| method_table, NELEM(method_table)); |
| } |
| |
| } // namespace android |