From 4d4eb9ac88f0bb633c469a4cd0b7b70adc98f02b Mon Sep 17 00:00:00 2001
From: Chen Bai <chenbai@google.com>
Date: Mon, 14 Nov 2022 15:14:15 -0800
Subject: [PATCH] fs-verity: fix broken test testInstallEverything

- Force GC on all processes listed by lsof to help this test walk around
  the FD leaks.

BUG: 253463456
Change-Id: Ida8cdfd8469452e028ad736497f5862a0df2a9a0
(cherry picked from commit 67884da910daeca4cb6da7568e7978fcaf4a55b3)
---
 .../com/android/apkverity/ApkVerityTest.java  | 36 +++++++++++++++++--
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/tests/ApkVerityTest/src/com/android/apkverity/ApkVerityTest.java b/tests/ApkVerityTest/src/com/android/apkverity/ApkVerityTest.java
index 16f005f288564..591ffeb397211 100644
--- a/tests/ApkVerityTest/src/com/android/apkverity/ApkVerityTest.java
+++ b/tests/ApkVerityTest/src/com/android/apkverity/ApkVerityTest.java
@@ -42,6 +42,7 @@ import java.io.FileNotFoundException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.Set;
 
 /**
  * This test makes sure app installs with fs-verity signature, and on-access verification works.
@@ -465,10 +466,10 @@ public class ApkVerityTest extends BaseHostJUnit4Test {
                     break;
                 }
                 try {
-                    CLog.d("lsof: " + expectRemoteCommandToSucceed("lsof " + apkPath));
+                    String openFiles = expectRemoteCommandToSucceed("lsof " + apkPath);
+                    CLog.d("lsof: " + openFiles);
                     Thread.sleep(1000);
-                    String pid = expectRemoteCommandToSucceed("pidof system_server");
-                    mDevice.executeShellV2Command("kill -10 " + pid);  // force GC
+                    forceGCOnOpenFilesProcess(getOpenFilesPIDs(openFiles));
                 } catch (InterruptedException e) {
                     Thread.currentThread().interrupt();
                     return;
@@ -478,6 +479,35 @@ public class ApkVerityTest extends BaseHostJUnit4Test {
         }
     }
 
+    /**
+     * This is a helper method that parses the lsof output to get PIDs of process holding FD.
+     * Here is an example output of lsof. This method extracts the second columns(PID).
+     *
+     * Example lsof output:
+     *  COMMAND      PID     USER    FD     TYPE   DEVICE   SIZE/OFF  NODE   NAME
+     * .example.app  1063    u0_a38  mem    REG    253,6    8599      12826  example.apk
+     * .example.app  1063    u0_a38  99r    REG    253,6    8599      12826  example.apk
+     */
+    private Set<String> getOpenFilesPIDs(String lsof) {
+        Set<String> openFilesPIDs = new HashSet<>();
+        String[] lines = lsof.split("\n");
+        for (int i = 1; i < lines.length; i++) {
+            openFilesPIDs.add(lines[i].split("\\s+")[1]);
+        }
+        return openFilesPIDs;
+    }
+
+    /**
+     * This is a helper method that forces GC on processes given their PIDs.
+     * That is to execute shell command "kill -10" on PIDs.
+     */
+    private void forceGCOnOpenFilesProcess(Set<String> openFilesPIDs)
+            throws DeviceNotAvailableException {
+        for (String openFilePID : openFilesPIDs) {
+            mDevice.executeShellV2Command("kill -10 " + openFilePID);
+        }
+    }
+
     private void verifyInstalledFiles(String... filenames) throws DeviceNotAvailableException {
         String apkPath = getApkPath(TARGET_PACKAGE);
         String appDir = apkPath.substring(0, apkPath.lastIndexOf("/"));