Support sound models with no data

This change allows using SoundModels with null or empty data.

Test: Manual testing of soundtrigger use-cases.
      Testing of null-/empty-data models using SoundTriggerTestService
      and mocked HAL.
Fixes: 181103994
Change-Id: I00b3c4e343a81e9f4f4580becf1128fd3ba60b14

core/java/android/hardware/soundtrigger/ConversionUtil.java

@@ -34,10 +34,7 @@ import android.media.soundtrigger_middleware.SoundTriggerModuleDescriptor;
 import android.media.soundtrigger_middleware.SoundTriggerModuleProperties;
 import android.os.ParcelFileDescriptor;
 import android.os.SharedMemory;
-import android.system.ErrnoException;
 
-import java.io.FileDescriptor;
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.UUID;
@@ -111,13 +108,9 @@ class ConversionUtil {
         aidlModel.type = apiModel.getType();
         aidlModel.uuid = api2aidlUuid(apiModel.getUuid());
         aidlModel.vendorUuid = api2aidlUuid(apiModel.getVendorUuid());
-        try {
-            aidlModel.data = ParcelFileDescriptor.dup(
-                    byteArrayToSharedMemory(apiModel.getData(), "SoundTrigger SoundModel"));
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-        aidlModel.dataSize = apiModel.getData().length;
+        byte[] data = apiModel.getData();
+        aidlModel.data = byteArrayToSharedMemory(data, "SoundTrigger SoundModel");
+        aidlModel.dataSize = data.length;
         return aidlModel;
     }
 
@@ -379,7 +372,7 @@ class ConversionUtil {
         return result;
     }
 
-    private static @Nullable FileDescriptor byteArrayToSharedMemory(byte[] data, String name) {
+    private static @Nullable ParcelFileDescriptor byteArrayToSharedMemory(byte[] data, String name) {
         if (data.length == 0) {
             return null;
         }
@@ -389,8 +382,10 @@ class ConversionUtil {
             ByteBuffer buffer = shmem.mapReadWrite();
             buffer.put(data);
             shmem.unmap(buffer);
-            return shmem.getFileDescriptor();
-        } catch (ErrnoException e) {
+            ParcelFileDescriptor fd = shmem.getFdDup();
+            shmem.close();
+            return fd;
+        } catch (Exception e) {
             throw new RuntimeException(e);
         }
     }

media/aidl/android/media/soundtrigger_middleware/SoundModel.aidl

@@ -32,8 +32,8 @@ parcelable SoundModel {
      * Unique vendor ID. Identifies the engine the sound model
      * was build for */
     String vendorUuid;
-    /** Opaque data transparent to Android framework */
-    ParcelFileDescriptor data;
+    /** Opaque data transparent to Android framework. May be null if dataSize is 0. */
+    @nullable ParcelFileDescriptor data;
     /** Size of the above data, in bytes. */
     int dataSize;
 }

services/core/java/com/android/server/soundtrigger_middleware/ConversionUtil.java

@@ -39,6 +39,7 @@ import android.media.soundtrigger_middleware.RecognitionStatus;
 import android.media.soundtrigger_middleware.SoundModel;
 import android.media.soundtrigger_middleware.SoundModelType;
 import android.media.soundtrigger_middleware.SoundTriggerModuleProperties;
+import android.os.HidlMemory;
 import android.os.HidlMemoryUtil;
 import android.os.ParcelFileDescriptor;
 
@@ -199,18 +200,7 @@ class ConversionUtil {
         hidlModel.header.type = aidl2hidlSoundModelType(aidlModel.type);
         hidlModel.header.uuid = aidl2hidlUuid(aidlModel.uuid);
         hidlModel.header.vendorUuid = aidl2hidlUuid(aidlModel.vendorUuid);
-
-        // Extract a dup of the underlying FileDescriptor out of aidlModel.data without changing
-        // the original.
-        FileDescriptor fd = new FileDescriptor();
-        try {
-            ParcelFileDescriptor dup = aidlModel.data.dup();
-            fd.setInt$(dup.detachFd());
-            hidlModel.data = HidlMemoryUtil.fileDescriptorToHidlMemory(fd, aidlModel.dataSize);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-
+        hidlModel.data = parcelFileDescriptorToHidlMemory(aidlModel.data, aidlModel.dataSize);
         return hidlModel;
     }
 
@@ -425,4 +415,31 @@ class ConversionUtil {
         }
         return aidlCapabilities;
     }
+
+    /**
+     * Convert an AIDL representation of a shared memory block (ParcelFileDescriptor + size) to the
+     * HIDL representation (HidlMemory). Will not change the incoming data or any ownership
+     * semantics, but rather duplicate the underlying FD.
+     *
+     * @param data     The incoming memory block. May be null if dataSize is 0.
+     * @param dataSize The number of bytes in the block.
+     * @return A HidlMemory representation of the memory block. Will be non-null even for an empty
+     *         block.
+     */
+    private static @NonNull
+    HidlMemory parcelFileDescriptorToHidlMemory(@Nullable ParcelFileDescriptor data, int dataSize) {
+        if (dataSize > 0) {
+            // Extract a dup of the underlying FileDescriptor out of data.
+            FileDescriptor fd = new FileDescriptor();
+            try {
+                ParcelFileDescriptor dup = data.dup();
+                fd.setInt$(dup.detachFd());
+                return HidlMemoryUtil.fileDescriptorToHidlMemory(fd, dataSize);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        } else {
+            return HidlMemoryUtil.fileDescriptorToHidlMemory(null, 0);
+        }
+    }
 }

services/core/java/com/android/server/soundtrigger_middleware/ValidationUtil.java

@@ -62,7 +62,9 @@ public class ValidationUtil {
         }
         validateUuid(model.uuid);
         validateUuid(model.vendorUuid);
-        Objects.requireNonNull(model.data);
+        if (model.dataSize > 0) {
+            Objects.requireNonNull(model.data);
+        }
     }
 
     static void validatePhraseModel(@Nullable PhraseSoundModel model) {