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Commit c959bb2a authored by T.J. Mercier's avatar T.J. Mercier
Browse files

Use libprocessgroup to find cgroup v2 paths 

Cgroup v2 paths are owned by libprocessgroup. Those paths can change
based on build flags, so paths generated outside of libprocessgroup may
not always be correct.

Additionally, the cpuacct controller has not been mounted at /acct since
2018 with commit 192aee782 ("libprocessgroup: Add support for task
profiles"), so remove the broken "v1" support.

Bug: 382693152
Flag: EXEMPT refactor
Test: atest FrameworksMockingServicesTests:AppChildProcessTest
Test: atest CtsAppTestCases:ActivityManagerTest
Change-Id: Ibd187b2d784ef4cb40099f30cd95206fb0536a98
parent 0e48e0a5

services/core/java/com/android/server/am/PhantomProcessList.java

+11 −24
Original line number Diff line number Diff line
@@ -112,23 +112,10 @@ public final class PhantomProcessList { 
    private final ActivityManagerService mService;

    private final Handler mKillHandler;



    private static final int CGROUP_V1 = 0;

    private static final int CGROUP_V2 = 1;

    private static final String[] CGROUP_PATH_PREFIXES = {

        "/acct/uid_" /* cgroup v1 */,

        "/sys/fs/cgroup/uid_" /* cgroup v2 */

    };

    private static final String CGROUP_PID_PREFIX = "/pid_";

    private static final String CGROUP_PROCS = "/cgroup.procs";



    @VisibleForTesting

    int mCgroupVersion = CGROUP_V1;



    PhantomProcessList(final ActivityManagerService service) {

        mService = service;

        mKillHandler = service.mProcessList.sKillHandler;

        mInjector = new Injector();

        probeCgroupVersion();

    }



    @VisibleForTesting
@@ -157,9 +144,15 @@ public final class PhantomProcessList { 
        final int appPid = app.getPid();

        InputStream input = mCgroupProcsFds.get(appPid);

        if (input == null) {

            final String path = getCgroupFilePath(app.info.uid, appPid);

            String path = null;

            try {

                path = getCgroupFilePath(app.info.uid, appPid);

                input = mInjector.openCgroupProcs(path);

            } catch (IllegalArgumentException e) {

                if (DEBUG_PROCESSES) {

                    Slog.w(TAG, "Unable to obtain cgroup.procs path ", e);

                }

                return;

            } catch (FileNotFoundException | SecurityException e) {

                if (DEBUG_PROCESSES) {

                    Slog.w(TAG, "Unable to open " + path, e);
@@ -207,18 +200,9 @@ public final class PhantomProcessList { 
        }

    }



    private void probeCgroupVersion() {

        for (int i = CGROUP_PATH_PREFIXES.length - 1; i >= 0; i--) {

            if ((new File(CGROUP_PATH_PREFIXES[i] + Process.SYSTEM_UID)).exists()) {

                mCgroupVersion = i;

                break;

            }

        }

    }



    @VisibleForTesting

    String getCgroupFilePath(int uid, int pid) {

        return CGROUP_PATH_PREFIXES[mCgroupVersion] + uid + CGROUP_PID_PREFIX + pid + CGROUP_PROCS;

        return nativeGetCgroupProcsPath(uid, pid);

    }



    static String getProcessName(int pid) {
@@ -630,4 +614,7 @@ public final class PhantomProcessList { 
            return PhantomProcessList.getProcessName(pid);

        }

    }



    private static native String nativeGetCgroupProcsPath(int uid, int pid)

            throws IllegalArgumentException;

}

services/core/jni/Android.bp

+8 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ cc_library_static { 
        ":lib_oomConnection_native",

        ":lib_anrTimer_native",

        ":lib_lazilyRegisteredServices_native",

        ":lib_phantomProcessList_native",

    ],



    include_dirs: [
@@ -265,3 +266,10 @@ filegroup { 
        "com_android_server_vr_VrManagerService.cpp",

    ],

}



filegroup {

    name: "lib_phantomProcessList_native",

    srcs: [

        "com_android_server_am_PhantomProcessList.cpp",

    ],

}

services/core/jni/com_android_server_am_PhantomProcessList.cpp

0 → 100644
+49 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2024 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 <jni.h>

#include <nativehelper/JNIHelp.h>

#include <processgroup/processgroup.h>



namespace android {

namespace {



jstring getCgroupProcsPath(JNIEnv* env, jobject clazz, jint uid, jint pid) {

    if (uid < 0) {

        jniThrowExceptionFmt(env, "java/lang/IllegalArgumentException", "uid is negative: %d", uid);

        return nullptr;

    }



    std::string path;

    if (!CgroupGetAttributePathForProcess("CgroupProcs", uid, pid, path)) {

        path.clear();

    }



    return env->NewStringUTF(path.c_str());

}



const JNINativeMethod sMethods[] = {

        {"nativeGetCgroupProcsPath", "(II)Ljava/lang/String;", (void*)getCgroupProcsPath},

};



} // anonymous namespace



int register_android_server_am_PhantomProcessList(JNIEnv* env) {

    const char* className = "com/android/server/am/PhantomProcessList";

    return jniRegisterNativeMethods(env, className, sMethods, NELEM(sMethods));

}



} // namespace android
 
 No newline at end of file

services/core/jni/onload.cpp

+2 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ int register_com_android_server_display_DisplayControl(JNIEnv* env); 
int register_com_android_server_SystemClockTime(JNIEnv* env);

int register_android_server_display_smallAreaDetectionController(JNIEnv* env);

int register_com_android_server_accessibility_BrailleDisplayConnection(JNIEnv* env);

int register_android_server_am_PhantomProcessList(JNIEnv* env);



// Note: Consider adding new JNI entrypoints for optional services to

// LazyJniRegistrar instead, and relying on lazy registration.
@@ -137,5 +138,6 @@ extern "C" jint JNI_OnLoad(JavaVM* vm, void* /* reserved */) 
    register_com_android_server_SystemClockTime(env);

    register_android_server_display_smallAreaDetectionController(env);

    register_com_android_server_accessibility_BrailleDisplayConnection(env);

    register_android_server_am_PhantomProcessList(env);

    return JNI_VERSION_1_4;

}

services/tests/mockingservicestests/jni/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ cc_library_shared { 
        ":lib_freezer_native",

        ":lib_oomConnection_native",

        ":lib_lazilyRegisteredServices_native",

        ":lib_phantomProcessList_native",

        "onload.cpp",

    ],