commit 272c7d32d02cb7bd1f07d6fa707a7cc0eec331fa
author Tim Murray <timmurray@google.com> Fri Jul 01 10:42:20 2016 -0700
committer The Android Automerger <android-build@google.com> Thu Jul 07 14:59:04 2016 -0700
tree a6e7b7d74e8aa87a61a7195d2ef3662e29b6fe63
parent 522b0248b2a22ee7a8d24580973f1ece5ceaf728

Add isThreadInProcess.

Use this to make sure that the VR thread belongs to a given process when
it is assigned.

bug 28715706

Change-Id: I4e5b0d8493e69e443eb907f0a6f2a9482fb64bac

core/java/android/os/Process.java

diff --git a/core/java/android/os/Process.java b/core/java/android/os/Process.java
index b9e46a5..24e7a63 100644
--- a/core/java/android/os/Process.java
+++ b/core/java/android/os/Process.java
@@ -19,6 +19,7 @@
 import android.net.LocalSocket;
 import android.net.LocalSocketAddress;
 import android.system.Os;
+import android.system.OsConstants;
 import android.util.Log;
 import com.android.internal.os.Zygote;
 import dalvik.system.VMRuntime;
@@ -1250,4 +1251,22 @@
      * @hide
      */
     public static final native void removeAllProcessGroups();
+
+    /**
+     * Check to see if a thread belongs to a given process. This may require
+     * more permissions than apps generally have.
+     * @return true if this thread belongs to a process
+     * @hide
+     */
+    public static final boolean isThreadInProcess(int tid, int pid) {
+        try {
+            if (Os.access("/proc/" + tid + "/task/" + pid, OsConstants.F_OK)) {
+                return true;
+            } else {
+                return false;
+            }
+        } catch (Exception e) {
+            return false;
+        }
+    }
 }

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

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index e5579e2..9f4bb56 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -12551,6 +12551,37 @@
     }
 
     @Override
+    public void setRenderThread(int tid) {
+        synchronized (this) {
+            ProcessRecord proc;
+            synchronized (mPidsSelfLocked) {
+                int pid = Binder.getCallingPid();
+                proc = mPidsSelfLocked.get(pid);
+                if (proc != null && proc.renderThreadTid == 0 && tid > 0) {
+                    // ensure the tid belongs to the process
+                    if (Process.isThreadInProcess(pid, tid) == false) {
+                        return;
+                    }
+                    proc.renderThreadTid = tid;
+                    if (DEBUG_OOM_ADJ) {
+                        Slog.d("UI_FIFO", "Set RenderThread tid " + tid + " for pid " + pid);
+                    }
+                    // promote to FIFO now
+                    if (proc.curSchedGroup == ProcessList.SCHED_GROUP_TOP_APP) {
+                        if (DEBUG_OOM_ADJ) Slog.d("UI_FIFO", "Promoting " + tid + "out of band");
+                        Process.setThreadScheduler(proc.renderThreadTid,
+                            Process.SCHED_FIFO | Process.SCHED_RESET_ON_FORK, 1);
+                    }
+                } else {
+                    if (DEBUG_OOM_ADJ) {
+                        Slog.d("UI_FIFO", "Didn't set thread from setRenderThreadForPid?");
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
     public int setVrMode(IBinder token, boolean enabled, ComponentName packageName) {
         if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_VR_MODE)) {
             throw new UnsupportedOperationException("VR mode not supported on this device!");