Add ProcessInfoService to activity manager.

- Adds a new AIDL interface for querying process
  information from activity manager.

Bug: 19186859

Change-Id: Ic08858f346d6b66e7bfc9da6faa2c6e38d9b2e82

include/binder/IProcessInfoService.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2015 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.
+ */
+
+#ifndef ANDROID_I_PROCESS_INFO_SERVICE_H
+#define ANDROID_I_PROCESS_INFO_SERVICE_H
+
+#include <binder/IInterface.h>
+
+namespace android {
+
+// ----------------------------------------------------------------------
+
+class IProcessInfoService : public IInterface {
+public:
+    DECLARE_META_INTERFACE(ProcessInfoService);
+
+    virtual status_t    getProcessStatesFromPids( size_t length,
+                                                  /*in*/ int32_t* pids,
+                                                  /*out*/ int32_t* states) = 0;
+
+    enum {
+        GET_PROCESS_STATES_FROM_PIDS = IBinder::FIRST_CALL_TRANSACTION,
+    };
+};
+
+// ----------------------------------------------------------------------
+
+class BnProcessInfoService : public BnInterface<IProcessInfoService> {
+public:
+    virtual status_t    onTransact( uint32_t code,
+                                    const Parcel& data,
+                                    Parcel* reply,
+                                    uint32_t flags = 0);
+};
+
+// ----------------------------------------------------------------------
+
+}; // namespace android
+
+#endif // ANDROID_I_PROCESS_INFO_SERVICE_H

include/binder/ProcessInfoService.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2015 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.
+ */
+
+#ifndef ANDROID_PROCESS_INFO_SERVICE_H
+#define ANDROID_PROCESS_INFO_SERVICE_H
+
+#include <binder/IProcessInfoService.h>
+#include <utils/Errors.h>
+#include <utils/Singleton.h>
+#include <sys/types.h>
+
+namespace android {
+
+// ----------------------------------------------------------------------
+
+class ProcessInfoService : public Singleton<ProcessInfoService> {
+
+    friend class Singleton<ProcessInfoService>;
+    sp<IProcessInfoService> mProcessInfoService;
+    Mutex mProcessInfoLock;
+
+    ProcessInfoService();
+
+    status_t getProcessStatesImpl(size_t length, /*in*/ int32_t* pids, /*out*/ int32_t* states);
+    void updateBinderLocked();
+
+    static const int BINDER_ATTEMPT_LIMIT = 5;
+
+public:
+
+    /**
+     * For each PID in the given "pids" input array, write the current process state
+     * for that process into the "states" output array, or
+     * ActivityManager.PROCESS_STATE_NONEXISTENT * to indicate that no process with the given PID
+     * exists.
+     *
+     * Returns NO_ERROR if this operation was successful, or a negative error code otherwise.
+     */
+    static status_t getProcessStatesFromPids(size_t length, /*in*/ int32_t* pids,
+            /*out*/ int32_t* states) {
+        return ProcessInfoService::getInstance().getProcessStatesImpl(length, /*in*/ pids,
+                /*out*/ states);
+    }
+
+};
+
+// ----------------------------------------------------------------------
+
+}; // namespace android
+
+#endif // ANDROID_PROCESS_INFO_SERVICE_H
+

libs/binder/Android.mk

@@ -26,6 +26,8 @@ sources := \
     IMemory.cpp \
     IPCThreadState.cpp \
     IPermissionController.cpp \
+    IProcessInfoService.cpp \
+    ProcessInfoService.cpp \
     IServiceManager.cpp \
     MemoryDealer.cpp \
     MemoryBase.cpp \

libs/binder/IProcessInfoService.cpp

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2015 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 <binder/IProcessInfoService.h>
+#include <binder/Parcel.h>
+#include <utils/Errors.h>
+#include <sys/types.h>
+
+namespace android {
+
+// ----------------------------------------------------------------------
+
+class BpProcessInfoService : public BpInterface<IProcessInfoService> {
+public:
+    BpProcessInfoService(const sp<IBinder>& impl)
+        : BpInterface<IProcessInfoService>(impl) {}
+
+    virtual status_t getProcessStatesFromPids(size_t length, /*in*/ int32_t* pids,
+            /*out*/ int32_t* states)
+    {
+        Parcel data, reply;
+        data.writeInterfaceToken(IProcessInfoService::getInterfaceDescriptor());
+        data.writeInt32Array(length, pids);
+        data.writeInt32(length); // write length of output array, used by java AIDL stubs
+        status_t err = remote()->transact(GET_PROCESS_STATES_FROM_PIDS, data, &reply);
+        if (err != NO_ERROR || ((err = reply.readExceptionCode()) != NO_ERROR)) {
+            return err;
+        }
+        int32_t replyLen = reply.readInt32();
+        if (static_cast<size_t>(replyLen) != length) {
+            return NOT_ENOUGH_DATA;
+        }
+        if (replyLen > 0 && (err = reply.read(states, length * sizeof(*states))) != NO_ERROR) {
+            return err;
+        }
+        return reply.readInt32();
+    }
+
+};
+
+IMPLEMENT_META_INTERFACE(ProcessInfoService, "android.os.IProcessInfoService");
+
+// ----------------------------------------------------------------------
+
+status_t BnProcessInfoService::onTransact( uint32_t code, const Parcel& data, Parcel* reply,
+        uint32_t flags) {
+    switch(code) {
+        case GET_PROCESS_STATES_FROM_PIDS: {
+            CHECK_INTERFACE(IProcessInfoService, data, reply);
+            int32_t arrayLen = data.readInt32();
+            if (arrayLen <= 0) {
+                reply->writeNoException();
+                reply->writeInt32(0);
+                reply->writeInt32(NOT_ENOUGH_DATA);
+                return NO_ERROR;
+            }
+
+            size_t len = static_cast<size_t>(arrayLen);
+            int32_t pids[len];
+            status_t res = data.read(pids, len * sizeof(*pids));
+
+            // Ignore output array length returned in the parcel here, as the states array must
+            // always be the same length as the input PIDs array.
+            int32_t states[len];
+            for (size_t i = 0; i < len; i++) states[i] = -1;
+            if (res == NO_ERROR) {
+                res = getProcessStatesFromPids(len, /*in*/ pids, /*out*/ states);
+            }
+            reply->writeNoException();
+            reply->writeInt32Array(len, states);
+            reply->writeInt32(res);
+            return NO_ERROR;
+        } break;
+        default:
+            return BBinder::onTransact(code, data, reply, flags);
+    }
+}
+
+// ----------------------------------------------------------------------
+
+}; // namespace android

libs/binder/ProcessInfoService.cpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2015 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 <binder/ProcessInfoService.h>
+#include <binder/IServiceManager.h>
+
+#include <utils/Log.h>
+#include <utils/String16.h>
+
+namespace android {
+
+ProcessInfoService::ProcessInfoService() {
+    updateBinderLocked();
+}
+
+status_t ProcessInfoService::getProcessStatesImpl(size_t length, /*in*/ int32_t* pids,
+        /*out*/ int32_t* states) {
+    status_t err = NO_ERROR;
+    sp<IProcessInfoService> pis;
+    mProcessInfoLock.lock();
+    pis = mProcessInfoService;
+    mProcessInfoLock.unlock();
+
+    for (int i = 0; i < BINDER_ATTEMPT_LIMIT; i++) {
+
+        if (pis != NULL) {
+            err = pis->getProcessStatesFromPids(length, /*in*/ pids, /*out*/ states);
+            if (err == NO_ERROR) return NO_ERROR; // success
+            if (IInterface::asBinder(pis)->isBinderAlive()) return err;
+        }
+        sleep(1);
+
+        mProcessInfoLock.lock();
+        if (pis == mProcessInfoService) {
+            updateBinderLocked();
+        }
+        pis = mProcessInfoService;
+        mProcessInfoLock.unlock();
+    }
+
+    ALOGW("%s: Could not retrieve process states from ProcessInfoService after %d retries.",
+            __FUNCTION__, BINDER_ATTEMPT_LIMIT);
+
+    return TIMED_OUT;
+}
+
+void ProcessInfoService::updateBinderLocked() {
+    const sp<IServiceManager> sm(defaultServiceManager());
+    if (sm != NULL) {
+        const String16 name("processinfo");
+        mProcessInfoService = interface_cast<IProcessInfoService>(sm->checkService(name));
+    }
+}
+
+ANDROID_SINGLETON_STATIC_INSTANCE(ProcessInfoService);
+
+}; // namespace android