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