1 /* 2 * Copyright 2022 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.system.virtualmachine; 18 19 import static java.util.Objects.requireNonNull; 20 21 import android.annotation.NonNull; 22 import android.annotation.Nullable; 23 import android.annotation.SystemApi; 24 import android.os.Parcel; 25 import android.os.ParcelFileDescriptor; 26 import android.os.Parcelable; 27 28 import java.io.IOException; 29 30 /** 31 * A VM descriptor that captures the state of a Virtual Machine. 32 * 33 * <p>You can capture the current state of VM by creating an instance of this class with {@link 34 * VirtualMachine#toDescriptor}, optionally pass it to another App, and then build an identical VM 35 * with the descriptor received. 36 * 37 * @hide 38 */ 39 @SystemApi 40 public final class VirtualMachineDescriptor implements Parcelable, AutoCloseable { 41 private volatile boolean mClosed = false; 42 @NonNull private final ParcelFileDescriptor mConfigFd; 43 @NonNull private final ParcelFileDescriptor mInstanceImgFd; 44 // File descriptor of the image backing the encrypted storage - Will be null if encrypted 45 // storage is not enabled. */ 46 @Nullable private final ParcelFileDescriptor mEncryptedStoreFd; 47 48 @Override describeContents()49 public int describeContents() { 50 return CONTENTS_FILE_DESCRIPTOR; 51 } 52 53 @Override writeToParcel(@onNull Parcel out, int flags)54 public void writeToParcel(@NonNull Parcel out, int flags) { 55 checkNotClosed(); 56 out.writeParcelable(mConfigFd, flags); 57 out.writeParcelable(mInstanceImgFd, flags); 58 out.writeParcelable(mEncryptedStoreFd, flags); 59 } 60 61 @NonNull 62 public static final Parcelable.Creator<VirtualMachineDescriptor> CREATOR = 63 new Parcelable.Creator<>() { 64 public VirtualMachineDescriptor createFromParcel(Parcel in) { 65 return new VirtualMachineDescriptor(in); 66 } 67 68 public VirtualMachineDescriptor[] newArray(int size) { 69 return new VirtualMachineDescriptor[size]; 70 } 71 }; 72 73 /** 74 * @return File descriptor of the VM configuration file config.xml. 75 */ 76 @NonNull getConfigFd()77 ParcelFileDescriptor getConfigFd() { 78 checkNotClosed(); 79 return mConfigFd; 80 } 81 82 /** 83 * @return File descriptor of the instance.img of the VM. 84 */ 85 @NonNull getInstanceImgFd()86 ParcelFileDescriptor getInstanceImgFd() { 87 checkNotClosed(); 88 return mInstanceImgFd; 89 } 90 91 /** 92 * @return File descriptor of image backing the encrypted storage. 93 * <p>This method will return null if encrypted storage is not enabled. 94 */ 95 @Nullable getEncryptedStoreFd()96 ParcelFileDescriptor getEncryptedStoreFd() { 97 checkNotClosed(); 98 return mEncryptedStoreFd; 99 } 100 VirtualMachineDescriptor( @onNull ParcelFileDescriptor configFd, @NonNull ParcelFileDescriptor instanceImgFd, @Nullable ParcelFileDescriptor encryptedStoreFd)101 VirtualMachineDescriptor( 102 @NonNull ParcelFileDescriptor configFd, 103 @NonNull ParcelFileDescriptor instanceImgFd, 104 @Nullable ParcelFileDescriptor encryptedStoreFd) { 105 mConfigFd = requireNonNull(configFd); 106 mInstanceImgFd = requireNonNull(instanceImgFd); 107 mEncryptedStoreFd = encryptedStoreFd; 108 } 109 VirtualMachineDescriptor(Parcel in)110 private VirtualMachineDescriptor(Parcel in) { 111 mConfigFd = requireNonNull(readParcelFileDescriptor(in)); 112 mInstanceImgFd = requireNonNull(readParcelFileDescriptor(in)); 113 mEncryptedStoreFd = readParcelFileDescriptor(in); 114 } 115 readParcelFileDescriptor(Parcel in)116 private ParcelFileDescriptor readParcelFileDescriptor(Parcel in) { 117 return in.readParcelable( 118 ParcelFileDescriptor.class.getClassLoader(), ParcelFileDescriptor.class); 119 } 120 121 /** 122 * Release any resources held by this descriptor. Calling {@code close} on an already-closed 123 * descriptor has no effect. 124 */ 125 @Override close()126 public void close() { 127 mClosed = true; 128 // Let the compiler do the work: close everything, throw if any of them fail, skipping null. 129 try (mConfigFd; 130 mInstanceImgFd; 131 mEncryptedStoreFd) { 132 } catch (IOException ignored) { 133 // PFD already swallows exceptions from closing the fd. There's no reason to propagate 134 // this to the caller. 135 } 136 } 137 checkNotClosed()138 private void checkNotClosed() { 139 if (mClosed) { 140 throw new IllegalStateException("Descriptor has been closed"); 141 } 142 } 143 } 144