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 #define LOG_TAG "VirtualizationService"
18
19 #include <android-base/unique_fd.h>
20 #include <android/avf_cc_flags.h>
21 #include <android/binder_ibinder_jni.h>
22 #include <jni.h>
23 #include <log/log.h>
24 #include <poll.h>
25
26 #include <string>
27
28 #include "common.h"
29
30 using namespace android::base;
31
32 static constexpr const char VIRTMGR_PATH[] = "/apex/com.android.virt/bin/virtmgr";
33 static constexpr size_t VIRTMGR_THREADS = 2;
34
35 extern "C" JNIEXPORT jint JNICALL
Java_android_system_virtualmachine_VirtualizationService_nativeSpawn(JNIEnv * env,jclass clazz)36 Java_android_system_virtualmachine_VirtualizationService_nativeSpawn(
37 JNIEnv* env, [[maybe_unused]] jclass clazz) {
38 unique_fd serverFd, clientFd;
39 if (!Socketpair(SOCK_STREAM, &serverFd, &clientFd)) {
40 env->ThrowNew(env->FindClass("android/system/virtualmachine/VirtualMachineException"),
41 ("Failed to create socketpair: " + std::string(strerror(errno))).c_str());
42 return -1;
43 }
44
45 unique_fd waitFd, readyFd;
46 if (!Pipe(&waitFd, &readyFd, 0)) {
47 env->ThrowNew(env->FindClass("android/system/virtualmachine/VirtualMachineException"),
48 ("Failed to create pipe: " + std::string(strerror(errno))).c_str());
49 return -1;
50 }
51
52 if (fork() == 0) {
53 // Close client's FDs.
54 clientFd.reset();
55 waitFd.reset();
56
57 auto strServerFd = std::to_string(serverFd.get());
58 auto strReadyFd = std::to_string(readyFd.get());
59
60 execl(VIRTMGR_PATH, VIRTMGR_PATH, "--rpc-server-fd", strServerFd.c_str(), "--ready-fd",
61 strReadyFd.c_str(), NULL);
62 }
63
64 // Close virtmgr's FDs.
65 serverFd.reset();
66 readyFd.reset();
67
68 // Wait for the server to signal its readiness by closing its end of the pipe.
69 char buf;
70 int ret = read(waitFd.get(), &buf, sizeof(buf));
71 if (ret < 0) {
72 env->ThrowNew(env->FindClass("android/system/virtualmachine/VirtualMachineException"),
73 "Failed to wait for VirtualizationService to be ready");
74 return -1;
75 } else if (ret < 1) {
76 env->ThrowNew(env->FindClass("java/lang/SecurityException"),
77 "Virtmgr didn't send any data through pipe. Please consider checking if "
78 "android.permission.MANAGE_VIRTUAL_MACHINE permission is granted");
79 return -1;
80 }
81
82 return clientFd.release();
83 }
84
85 extern "C" JNIEXPORT jobject JNICALL
Java_android_system_virtualmachine_VirtualizationService_nativeConnect(JNIEnv * env,jobject obj,int clientFd)86 Java_android_system_virtualmachine_VirtualizationService_nativeConnect(JNIEnv* env,
87 [[maybe_unused]] jobject obj,
88 int clientFd) {
89 RpcSessionHandle session;
90 ARpcSession_setFileDescriptorTransportMode(session.get(),
91 ARpcSession_FileDescriptorTransportMode::Unix);
92 ARpcSession_setMaxIncomingThreads(session.get(), VIRTMGR_THREADS);
93 // SAFETY - ARpcSession_setupUnixDomainBootstrapClient does not take ownership of clientFd.
94 auto client = ARpcSession_setupUnixDomainBootstrapClient(session.get(), clientFd);
95 return AIBinder_toJavaBinder(env, client);
96 }
97
98 extern "C" JNIEXPORT jboolean JNICALL
Java_android_system_virtualmachine_VirtualizationService_nativeIsOk(JNIEnv * env,jobject obj,int clientFd)99 Java_android_system_virtualmachine_VirtualizationService_nativeIsOk(JNIEnv* env,
100 [[maybe_unused]] jobject obj,
101 int clientFd) {
102 /* Setting events=0 only returns POLLERR, POLLHUP or POLLNVAL. */
103 struct pollfd pfds[] = {{.fd = clientFd, .events = 0}};
104 if (poll(pfds, /*nfds*/ 1, /*timeout*/ 0) < 0) {
105 env->ThrowNew(env->FindClass("android/system/virtualmachine/VirtualMachineException"),
106 ("Failed to poll client FD: " + std::string(strerror(errno))).c_str());
107 return false;
108 }
109 return pfds[0].revents == 0;
110 }
111
112 extern "C" JNIEXPORT jboolean JNICALL
Java_android_system_virtualmachine_VirtualizationService_nativeIsVendorModulesFlagEnabled(JNIEnv * env,jobject obj)113 Java_android_system_virtualmachine_VirtualizationService_nativeIsVendorModulesFlagEnabled(
114 [[maybe_unused]] JNIEnv* env, [[maybe_unused]] jobject obj) {
115 return android::virtualization::IsVendorModulesFlagEnabled();
116 }
117