diff --git a/core/java/android/os/Environment.java b/core/java/android/os/Environment.java
index 6d5fe53b..a92237b 100644
--- a/core/java/android/os/Environment.java
+++ b/core/java/android/os/Environment.java
@@ -55,6 +55,7 @@
     private static final String ENV_VENDOR_ROOT = "VENDOR_ROOT";
     private static final String ENV_PRODUCT_ROOT = "PRODUCT_ROOT";
     private static final String ENV_SYSTEM_EXT_ROOT = "SYSTEM_EXT_ROOT";
+    private static final String ENV_APEX_ROOT = "APEX_ROOT";
 
     /** {@hide} */
     public static final String DIR_ANDROID = "Android";
@@ -78,7 +79,9 @@
     private static final File DIR_VENDOR_ROOT = getDirectory(ENV_VENDOR_ROOT, "/vendor");
     private static final File DIR_PRODUCT_ROOT = getDirectory(ENV_PRODUCT_ROOT, "/product");
     private static final File DIR_SYSTEM_EXT_ROOT = getDirectory(ENV_SYSTEM_EXT_ROOT,
-                                                           "/system_ext");
+            "/system_ext");
+    private static final File DIR_APEX_ROOT = getDirectory(ENV_APEX_ROOT,
+            "/apex");
 
     @UnsupportedAppUsage
     private static UserEnvironment sCurrentUser;
@@ -248,6 +251,16 @@
     }
 
     /**
+     * Return root directory of the apex mount point, where all the apex modules are made available
+     * to the rest of the system.
+     *
+     * @hide
+     */
+    public static @NonNull File getApexDirectory() {
+        return DIR_APEX_ROOT;
+    }
+
+    /**
      * Return the system directory for a user. This is for use by system
      * services to store files relating to the user. This directory will be
      * automatically deleted when the user is removed.
diff --git a/services/core/java/com/android/server/pm/ApexManager.java b/services/core/java/com/android/server/pm/ApexManager.java
index fd44cbb..12e8069 100644
--- a/services/core/java/com/android/server/pm/ApexManager.java
+++ b/services/core/java/com/android/server/pm/ApexManager.java
@@ -32,6 +32,7 @@
 import android.content.pm.PackageInstaller;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageParser;
+import android.os.Environment;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.sysprop.ApexProperties;
@@ -47,6 +48,7 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -64,9 +66,9 @@
     static final int MATCH_FACTORY_PACKAGE = 1 << 1;
 
     /**
-     * Returns an instance of either {@link ApexManagerImpl} or {@link ApexManagerNoOp} depending
-     * on whenever this device supports APEX, i.e. {@link ApexProperties#updatable()} evaluates to
-     * {@code true}.
+     * Returns an instance of either {@link ApexManagerImpl} or {@link ApexManagerFlattenedApex}
+     * depending on whether this device supports APEX, i.e. {@link ApexProperties#updatable()}
+     * evaluates to {@code true}.
      */
     static ApexManager create(Context systemContext) {
         if (ApexProperties.updatable().orElse(false)) {
@@ -77,10 +79,28 @@
                 throw new IllegalStateException("Required service apexservice not available");
             }
         } else {
-            return new ApexManagerNoOp();
+            return new ApexManagerFlattenedApex();
         }
     }
 
+    /**
+     * Minimal information about APEX mount points and the original APEX package they refer to.
+     */
+    static class ActiveApexInfo {
+        public final File apexDirectory;
+        public final File preinstalledApexPath;
+
+        private ActiveApexInfo(File apexDirectory, File preinstalledApexPath) {
+            this.apexDirectory = apexDirectory;
+            this.preinstalledApexPath = preinstalledApexPath;
+        }
+    }
+
+    /**
+     * Returns {@link ActiveApexInfo} records relative to all active APEX packages.
+     */
+    abstract List<ActiveApexInfo> getActiveApexInfos();
+
     abstract void systemReady();
 
     /**
@@ -259,6 +279,22 @@
         }
 
         @Override
+        List<ActiveApexInfo> getActiveApexInfos() {
+            try {
+                return Arrays.stream(mApexService.getActivePackages())
+                        .map(apexInfo -> new ActiveApexInfo(
+                                new File(
+                                Environment.getApexDirectory() + File.separator
+                                        + apexInfo.moduleName),
+                                new File(apexInfo.modulePath))).collect(
+                                Collectors.toList());
+            } catch (RemoteException e) {
+                Slog.e(TAG, "Unable to retrieve packages from apexservice", e);
+            }
+            return Collections.emptyList();
+        }
+
+        @Override
         void systemReady() {
             mContext.registerReceiver(new BroadcastReceiver() {
                 @Override
@@ -549,7 +585,40 @@
      * An implementation of {@link ApexManager} that should be used in case device does not support
      * updating APEX packages.
      */
-    private static final class ApexManagerNoOp extends ApexManager {
+    private static final class ApexManagerFlattenedApex extends ApexManager {
+
+        @Override
+        List<ActiveApexInfo> getActiveApexInfos() {
+            // There is no apexd running in case of flattened apex
+            // We look up the /apex directory and identify the active APEX modules from there.
+            // As "preinstalled" path, we just report /system since in the case of flattened APEX
+            // the /apex directory is just a symlink to /system/apex.
+            List<ActiveApexInfo> result = new ArrayList<>();
+            File apexDir = Environment.getApexDirectory();
+            // In flattened configuration, init special-case the art directory and bind-mounts
+            // com.android.art.{release|debug} to com.android.art. At the time of writing, these
+            // directories are copied from the kArtApexDirNames variable in
+            // system/core/init/mount_namespace.cpp.
+            String[] skipDirs = {"com.android.art.release", "com.android.art.debug"};
+            if (apexDir.isDirectory()) {
+                File[] files = apexDir.listFiles();
+                // listFiles might be null if system server doesn't have permission to read
+                // a directory.
+                if (files != null) {
+                    for (File file : files) {
+                        if (file.isDirectory() && !file.getName().contains("@")) {
+                            for (String skipDir : skipDirs) {
+                                if (file.getName().equals(skipDir)) {
+                                    continue;
+                                }
+                            }
+                            result.add(new ActiveApexInfo(file, Environment.getRootDirectory()));
+                        }
+                    }
+                }
+            }
+            return result;
+        }
 
         @Override
         void systemReady() {
diff --git a/services/core/java/com/android/server/pm/PackageAbiHelperImpl.java b/services/core/java/com/android/server/pm/PackageAbiHelperImpl.java
index 1d3d24c..259200b 100644
--- a/services/core/java/com/android/server/pm/PackageAbiHelperImpl.java
+++ b/services/core/java/com/android/server/pm/PackageAbiHelperImpl.java
@@ -67,6 +67,15 @@
             codeRoot = Environment.getSystemExtDirectory();
         } else if (FileUtils.contains(Environment.getOdmDirectory(), codePath)) {
             codeRoot = Environment.getOdmDirectory();
+        } else if (FileUtils.contains(Environment.getApexDirectory(), codePath)) {
+            String fullPath = codePath.getAbsolutePath();
+            String[] parts = fullPath.split(File.separator);
+            if (parts.length > 2) {
+                codeRoot = new File(parts[1] + File.separator + parts[2]);
+            } else {
+                Slog.w(PackageManagerService.TAG, "Can't canonicalize code path " + codePath);
+                codeRoot = Environment.getApexDirectory();
+            }
         } else {
             // Unrecognized code path; take its top real segment as the apk root:
             // e.g. /something/app/blah.apk => /something
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index b5fa80d1..74a85d5 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -370,6 +370,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
+import java.util.stream.Collectors;
 
 /**
  * Keep track of all those APKs everywhere.
@@ -762,6 +763,8 @@
                     new SystemPartition(Environment.getSystemExtDirectory(), SCAN_AS_SYSTEM_EXT,
                             true /* hasPriv */, true /* hasOverlays */)));
 
+    private final List<SystemPartition> mDirsToScanAsSystem;
+
     /**
      * Unit tests will instantiate, extend and/or mock to mock dependencies / behaviors.
      *
@@ -2552,6 +2555,16 @@
         mApexManager = ApexManager.create(mContext);
         mAppsFilter = mInjector.getAppsFilter();
 
+        mDirsToScanAsSystem = new ArrayList<>();
+        mDirsToScanAsSystem.addAll(SYSTEM_PARTITIONS);
+        mDirsToScanAsSystem.addAll(mApexManager.getActiveApexInfos().stream()
+                .map(ai -> resolveApexToSystemPartition(ai))
+                .filter(Objects::nonNull).collect(Collectors.toList()));
+        Slog.d(TAG,
+                "Directories scanned as system partitions: [" + mDirsToScanAsSystem.stream().map(
+                        d -> (d.folder.getAbsolutePath() + ":" + d.scanFlag))
+                        .collect(Collectors.joining(",")) + "]");
+
         // CHECKSTYLE:OFF IndentationCheck
         synchronized (mInstallLock) {
         // writer
@@ -2684,8 +2697,8 @@
             // reside in the right directory.
             final int systemParseFlags = mDefParseFlags | PackageParser.PARSE_IS_SYSTEM_DIR;
             final int systemScanFlags = scanFlags | SCAN_AS_SYSTEM;
-            for (int i = SYSTEM_PARTITIONS.size() - 1; i >= 0; i--) {
-                final SystemPartition partition = SYSTEM_PARTITIONS.get(i);
+            for (int i = mDirsToScanAsSystem.size() - 1; i >= 0; i--) {
+                final SystemPartition partition = mDirsToScanAsSystem.get(i);
                 if (partition.overlayFolder == null) {
                     continue;
                 }
@@ -2699,8 +2712,8 @@
                 throw new IllegalStateException(
                         "Failed to load frameworks package; check log for warnings");
             }
-            for (int i = 0, size = SYSTEM_PARTITIONS.size(); i < size; i++) {
-                final SystemPartition partition = SYSTEM_PARTITIONS.get(i);
+            for (int i = 0, size = mDirsToScanAsSystem.size(); i < size; i++) {
+                final SystemPartition partition = mDirsToScanAsSystem.get(i);
                 if (partition.privAppFolder != null) {
                     scanDirTracedLI(partition.privAppFolder, systemParseFlags,
                             systemScanFlags | SCAN_AS_PRIVILEGED | partition.scanFlag, 0);
@@ -2878,8 +2891,8 @@
 
                         @ParseFlags int reparseFlags = 0;
                         @ScanFlags int rescanFlags = 0;
-                        for (int i1 = 0, size = SYSTEM_PARTITIONS.size(); i1 < size; i1++) {
-                            SystemPartition partition = SYSTEM_PARTITIONS.get(i1);
+                        for (int i1 = 0, size = mDirsToScanAsSystem.size(); i1 < size; i1++) {
+                            SystemPartition partition = mDirsToScanAsSystem.get(i1);
                             if (partition.containsPrivApp(scanFile)) {
                                 reparseFlags = systemParseFlags;
                                 rescanFlags = systemScanFlags | SCAN_AS_PRIVILEGED
@@ -17778,6 +17791,7 @@
     }
 
     static boolean locationIsPrivileged(String path) {
+        // TODO(dariofreni): include APEX partitions when they will support priv apps.
         for (int i = 0, size = SYSTEM_PARTITIONS.size(); i < size; i++) {
             SystemPartition partition = SYSTEM_PARTITIONS.get(i);
             if (partition.containsPrivPath(path)) {
@@ -17787,6 +17801,18 @@
         return false;
     }
 
+    private static @Nullable SystemPartition resolveApexToSystemPartition(
+            ApexManager.ActiveApexInfo apexInfo) {
+        for (int i = 0, size = SYSTEM_PARTITIONS.size(); i < size; i++) {
+            SystemPartition sp = SYSTEM_PARTITIONS.get(i);
+            if (apexInfo.preinstalledApexPath.getAbsolutePath().startsWith(
+                    sp.folder.getAbsolutePath())) {
+                return new SystemPartition(apexInfo.apexDirectory, sp.scanFlag,
+                        false /* hasPriv */, false /* hasOverlays */);
+            }
+        }
+        return null;
+    }
 
     /*
      * Tries to delete system package.
@@ -17897,8 +17923,8 @@
                 | PackageParser.PARSE_MUST_BE_APK
                 | PackageParser.PARSE_IS_SYSTEM_DIR;
         @ScanFlags int scanFlags = SCAN_AS_SYSTEM;
-        for (int i = 0, size = SYSTEM_PARTITIONS.size(); i < size; i++) {
-            SystemPartition partition = SYSTEM_PARTITIONS.get(i);
+        for (int i = 0, size = mDirsToScanAsSystem.size(); i < size; i++) {
+            SystemPartition partition = mDirsToScanAsSystem.get(i);
             if (partition.containsPath(codePathString)) {
                 scanFlags |= partition.scanFlag;
                 if (partition.containsPrivPath(codePathString)) {