Parse proto tombstones.

Bug: http://b/159164105
Test: manual
Change-Id: I8b85d8eeb343f390567b9d11bafcaa0d9aebddc7

Android.bp

@@ -678,6 +678,7 @@ gensrcs {
     srcs: [
         ":ipconnectivity-proto-src",
         ":libstats_atom_enum_protos",
+        ":libtombstone_proto-src",
         "core/proto/**/*.proto",
         "libs/incident/**/*.proto",
     ],

services/core/java/com/android/server/os/NativeTombstoneManager.java

@@ -16,17 +16,33 @@
 
 package com.android.server.os;
 
+import static android.os.ParcelFileDescriptor.MODE_READ_WRITE;
 import static android.os.Process.THREAD_PRIORITY_BACKGROUND;
 
+import android.annotation.AppIdInt;
 import android.annotation.Nullable;
+import android.annotation.UserIdInt;
 import android.content.Context;
 import android.os.FileObserver;
 import android.os.Handler;
+import android.os.ParcelFileDescriptor;
+import android.os.UserHandle;
+import android.util.Slog;
+import android.util.SparseArray;
+import android.util.proto.ProtoInputStream;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.server.BootReceiver;
 import com.android.server.ServiceThread;
+import com.android.server.os.TombstoneProtos.Tombstone;
+
+import libcore.io.IoUtils;
 
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.Optional;
 
 /**
  * A class to manage native tombstones.
@@ -40,7 +56,13 @@ public final class NativeTombstoneManager {
     private final Handler mHandler;
     private final TombstoneWatcher mWatcher;
 
+    private final Object mLock = new Object();
+
+    @GuardedBy("mLock")
+    private final SparseArray<TombstoneFile> mTombstones;
+
     NativeTombstoneManager(Context context) {
+        mTombstones = new SparseArray<TombstoneFile>();
         mContext = context;
 
         final ServiceThread thread = new ServiceThread(TAG + ":tombstoneWatcher",
@@ -70,7 +92,135 @@ public final class NativeTombstoneManager {
             return;
         }
 
-        BootReceiver.addTombstoneToDropBox(mContext, path);
+        if (filename.endsWith(".pb")) {
+            handleProtoTombstone(path);
+        } else {
+            BootReceiver.addTombstoneToDropBox(mContext, path);
+        }
+    }
+
+    private void handleProtoTombstone(File path) {
+        final String filename = path.getName();
+        if (!filename.endsWith(".pb")) {
+            Slog.w(TAG, "unexpected tombstone name: " + path);
+            return;
+        }
+
+        final String suffix = filename.substring("tombstone_".length());
+        final String numberStr = suffix.substring(0, suffix.length() - 3);
+
+        int number;
+        try {
+            number = Integer.parseInt(numberStr);
+            if (number < 0 || number > 99) {
+                Slog.w(TAG, "unexpected tombstone name: " + path);
+                return;
+            }
+        } catch (NumberFormatException ex) {
+            Slog.w(TAG, "unexpected tombstone name: " + path);
+            return;
+        }
+
+        ParcelFileDescriptor pfd;
+        try {
+            pfd = ParcelFileDescriptor.open(path, MODE_READ_WRITE);
+        } catch (FileNotFoundException ex) {
+            Slog.w(TAG, "failed to open " + path, ex);
+            return;
+        }
+
+        final Optional<TombstoneFile> parsedTombstone = TombstoneFile.parse(pfd);
+        if (!parsedTombstone.isPresent()) {
+            IoUtils.closeQuietly(pfd);
+            return;
+        }
+
+        synchronized (mLock) {
+            TombstoneFile previous = mTombstones.get(number);
+            if (previous != null) {
+                previous.dispose();
+            }
+
+            mTombstones.put(number, parsedTombstone.get());
+        }
+    }
+
+    static class TombstoneFile {
+        final ParcelFileDescriptor mPfd;
+
+        final @UserIdInt int mUserId;
+        final @AppIdInt int mAppId;
+
+        boolean mPurged = false;
+
+        TombstoneFile(ParcelFileDescriptor pfd, @UserIdInt int userId, @AppIdInt int appId) {
+            mPfd = pfd;
+            mUserId = userId;
+            mAppId = appId;
+        }
+
+        public boolean matches(Optional<Integer> userId, Optional<Integer> appId) {
+            if (mPurged) {
+                return false;
+            }
+
+            if (userId.isPresent() && userId.get() != mUserId) {
+                return false;
+            }
+
+            if (appId.isPresent() && appId.get() != mAppId) {
+                return false;
+            }
+
+            return true;
+        }
+
+        public void dispose() {
+            IoUtils.closeQuietly(mPfd);
+        }
+
+        static Optional<TombstoneFile> parse(ParcelFileDescriptor pfd) {
+            final FileInputStream is = new FileInputStream(pfd.getFileDescriptor());
+            final ProtoInputStream stream = new ProtoInputStream(is);
+
+            int uid = 0;
+            String selinuxLabel = "";
+
+            try {
+                while (stream.nextField() != ProtoInputStream.NO_MORE_FIELDS) {
+                    switch (stream.getFieldNumber()) {
+                        case (int) Tombstone.UID:
+                            uid = stream.readInt(Tombstone.UID);
+                            break;
+
+                        case (int) Tombstone.SELINUX_LABEL:
+                            selinuxLabel = stream.readString(Tombstone.SELINUX_LABEL);
+                            break;
+
+                        default:
+                            break;
+                    }
+                }
+            } catch (IOException ex) {
+                Slog.e(TAG, "Failed to parse tombstone", ex);
+                return Optional.empty();
+            }
+
+            if (!UserHandle.isApp(uid)) {
+                Slog.e(TAG, "Tombstone's UID (" + uid + ") not an app, ignoring");
+                return Optional.empty();
+            }
+
+            final int userId = UserHandle.getUserId(uid);
+            final int appId = UserHandle.getAppId(uid);
+
+            if (!selinuxLabel.startsWith("u:r:untrusted_app")) {
+                Slog.e(TAG, "Tombstone has invalid selinux label (" + selinuxLabel + "), ignoring");
+                return Optional.empty();
+            }
+
+            return Optional.of(new TombstoneFile(pfd, userId, appId));
+        }
     }
 
     class TombstoneWatcher extends FileObserver {