/*
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* Copyright (C) 2019 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 LOG_TAG "AppCompactor"
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//#define LOG_NDEBUG 0
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#include <dirent.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <android-base/stringprintf.h>
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#include <android-base/file.h>
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#include <nativehelper/JNIHelp.h>
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#include <android_runtime/AndroidRuntime.h>
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#include <jni.h>
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using android::base::StringPrintf;
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using android::base::WriteStringToFile;
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namespace android {
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// This performs per-process reclaim on all processes belonging to non-app UIDs.
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// For the most part, these are non-zygote processes like Treble HALs, but it
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// also includes zygote-derived processes that run in system UIDs, like bluetooth
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// or potentially some mainline modules. The only process that should definitely
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// not be compacted is system_server, since compacting system_server around the
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// time of BOOT_COMPLETE could result in perceptible issues.
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static void com_android_server_am_AppCompactor_compactSystem(JNIEnv *, jobject) {
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std::unique_ptr<DIR, decltype(&closedir)> proc(opendir("/proc"), closedir);
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struct dirent* current;
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while ((current = readdir(proc.get()))) {
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if (current->d_type != DT_DIR) {
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continue;
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}
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// don't compact system_server, rely on persistent compaction during screen off
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// in order to avoid mmap_sem-related stalls
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if (atoi(current->d_name) == getpid()) {
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continue;
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}
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std::string status_name = StringPrintf("/proc/%s/status", current->d_name);
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struct stat status_info;
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if (stat(status_name.c_str(), &status_info) != 0) {
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// must be some other directory that isn't a pid
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continue;
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}
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// android.os.Process.FIRST_APPLICATION_UID
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if (status_info.st_uid >= 10000) {
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continue;
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}
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std::string reclaim_path = StringPrintf("/proc/%s/reclaim", current->d_name);
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WriteStringToFile(std::string("all"), reclaim_path);
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}
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}
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static const JNINativeMethod sMethods[] = {
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/* name, signature, funcPtr */
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{"compactSystem", "()V", (void*)com_android_server_am_AppCompactor_compactSystem},
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};
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int register_android_server_am_AppCompactor(JNIEnv* env)
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{
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return jniRegisterNativeMethods(env, "com/android/server/am/AppCompactor",
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sMethods, NELEM(sMethods));
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}
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}
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