Add agent startup-attach

Add ability to give 'startup-agents' that are automatically loaded
when a (debuggable) app starts. These agents are any files in the
'code_cache/startup_agents' directory. The agents are started with the
apps data_directory as an argument.

Test: Install debuggable apk (here com.antonioleiva.bandhookkotlin)
  walleye:/ $ run-as com.antonioleiva.bandhookkotlin sh
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ mkdir code_cache/startup_agents
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ cp /data/local/tmp/libtifasts32.so code_cache
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ cp /data/local/tmp/libtifasts64.so code_cache
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ cp /data/local/tmp/libchainagentss32.so code_cache/startup_agents/
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ cp /data/local/tmp/libchainagentss64.so code_cache/startup_agents/
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ echo $PWD/code_cache/libtifasts32.so=log,ClassLoad > chain_agents.txt
  walleye:/data/data/com.antonioleiva.bandhookkotlin $ echo $PWD/code_cache/libtifasts64.so=log,ClassLoad >> chain_agents.txt
  Start bandhookkotlin
  Examine logcat

Bug: 135627501

Change-Id: Ib82b27df90c7964a995288d8b2b3d348a11cdd80
(cherry picked from commit c0fce111c8b7c68ddb397ac7c65ac5c35a40da01)

1 files changed, 22 insertions, 0 deletions

diff --git a/core/java/android/app/ActivityThread.java b/core/java/android/app/ActivityThread.java
index 553ef69fe8e2..a6784780d72f 100644
--- a/core/java/android/app/ActivityThread.java
+++ b/core/java/android/app/ActivityThread.java
@@ -191,6 +191,8 @@ import java.io.PrintWriter;
 import java.lang.ref.WeakReference;
 import java.lang.reflect.Method;
 import java.net.InetAddress;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.text.DateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -6435,6 +6437,26 @@ public final class ActivityThread extends ClientTransactionHandler {
         NetworkSecurityConfigProvider.install(appContext);
         Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
 
+
+        if (isAppDebuggable) {
+            try {
+                // Load all the agents in the code_cache/startup_agents directory.
+                // We pass the absolute path to the data_dir as an argument.
+                Path startup_path = appContext.getCodeCacheDir().toPath().resolve("startup_agents");
+                if (Files.exists(startup_path)) {
+                    for (Path p : Files.newDirectoryStream(startup_path)) {
+                        handleAttachAgent(
+                                p.toAbsolutePath().toString()
+                                + "="
+                                + appContext.getDataDir().toPath().toAbsolutePath().toString(),
+                                data.info);
+                    }
+                }
+            } catch (Exception e) {
+                // Ignored.
+            }
+        }
+
         // Continue loading instrumentation.
         if (ii != null) {
             ApplicationInfo instrApp;