1 /*
2 * copyright (C) 2011 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 #include <signal.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <algorithm>
22 #include <memory>
23
24 #include "jni.h"
25 #include "nativehelper/JniInvocation.h"
26 #include "nativehelper/ScopedLocalRef.h"
27 #include "nativehelper/toStringArray.h"
28
29 namespace art {
30
31 // Determine whether or not the specified method is public.
IsMethodPublic(JNIEnv * env,jclass c,jmethodID method_id)32 static bool IsMethodPublic(JNIEnv* env, jclass c, jmethodID method_id) {
33 ScopedLocalRef<jobject> reflected(env, env->ToReflectedMethod(c, method_id, JNI_FALSE));
34 if (reflected.get() == nullptr) {
35 fprintf(stderr, "Failed to get reflected method\n");
36 return false;
37 }
38 // We now have a Method instance. We need to call its
39 // getModifiers() method.
40 jclass method_class = env->FindClass("java/lang/reflect/Method");
41 if (method_class == nullptr) {
42 fprintf(stderr, "Failed to find class java.lang.reflect.Method\n");
43 return false;
44 }
45 jmethodID mid = env->GetMethodID(method_class, "getModifiers", "()I");
46 if (mid == nullptr) {
47 fprintf(stderr, "Failed to find java.lang.reflect.Method.getModifiers\n");
48 return false;
49 }
50 int modifiers = env->CallIntMethod(reflected.get(), mid);
51 static const int PUBLIC = 0x0001; // java.lang.reflect.Modifiers.PUBLIC
52 if ((modifiers & PUBLIC) == 0) {
53 fprintf(stderr, "Modifiers mismatch\n");
54 return false;
55 }
56 return true;
57 }
58
InvokeMain(JNIEnv * env,char ** argv)59 static int InvokeMain(JNIEnv* env, char** argv) {
60 // We want to call main() with a String array with our arguments in
61 // it. Create an array and populate it. Note argv[0] is not
62 // included.
63 ScopedLocalRef<jobjectArray> args(env, toStringArray(env, argv + 1));
64 if (args.get() == nullptr) {
65 env->ExceptionDescribe();
66 return EXIT_FAILURE;
67 }
68
69 // Find [class].main(String[]).
70
71 // Convert "com.android.Blah" to "com/android/Blah".
72 std::string class_name(argv[0]);
73 std::replace(class_name.begin(), class_name.end(), '.', '/');
74
75 ScopedLocalRef<jclass> klass(env, env->FindClass(class_name.c_str()));
76 if (klass.get() == nullptr) {
77 fprintf(stderr, "Unable to locate class '%s'\n", class_name.c_str());
78 env->ExceptionDescribe();
79 return EXIT_FAILURE;
80 }
81
82 jmethodID method = env->GetStaticMethodID(klass.get(), "main", "([Ljava/lang/String;)V");
83 if (method == nullptr) {
84 fprintf(stderr, "Unable to find static main(String[]) in '%s'\n", class_name.c_str());
85 env->ExceptionDescribe();
86 return EXIT_FAILURE;
87 }
88
89 // Make sure the method is public. JNI doesn't prevent us from
90 // calling a private method, so we have to check it explicitly.
91 if (!IsMethodPublic(env, klass.get(), method)) {
92 fprintf(stderr, "Sorry, main() is not public in '%s'\n", class_name.c_str());
93 env->ExceptionDescribe();
94 return EXIT_FAILURE;
95 }
96
97 // Invoke main().
98 env->CallStaticVoidMethod(klass.get(), method, args.get());
99
100 // Check whether there was an uncaught exception. We don't log any uncaught exception here;
101 // detaching this thread will do that for us, but it will clear the exception (and invalidate
102 // our JNIEnv), so we need to check here.
103 return env->ExceptionCheck() ? EXIT_FAILURE : EXIT_SUCCESS;
104 }
105
106 // Parse arguments. Most of it just gets passed through to the runtime.
107 // The JNI spec defines a handful of standard arguments.
dalvikvm(int argc,char ** argv)108 static int dalvikvm(int argc, char** argv) {
109 setvbuf(stdout, nullptr, _IONBF, 0);
110
111 // Skip over argv[0].
112 argv++;
113 argc--;
114
115 // If we're adding any additional stuff, e.g. function hook specifiers,
116 // add them to the count here.
117 //
118 // We're over-allocating, because this includes the options to the runtime
119 // plus the options to the program.
120 int option_count = argc;
121 std::unique_ptr<JavaVMOption[]> options(new JavaVMOption[option_count]());
122
123 // Copy options over. Everything up to the name of the class starts
124 // with a '-' (the function hook stuff is strictly internal).
125 //
126 // [Do we need to catch & handle "-jar" here?]
127 bool need_extra = false;
128 const char* lib = nullptr;
129 const char* what = nullptr;
130 int curr_opt, arg_idx;
131 for (curr_opt = arg_idx = 0; arg_idx < argc; arg_idx++) {
132 if (argv[arg_idx][0] != '-' && !need_extra) {
133 break;
134 }
135 if (strncmp(argv[arg_idx], "-XXlib:", strlen("-XXlib:")) == 0) {
136 lib = argv[arg_idx] + strlen("-XXlib:");
137 continue;
138 }
139
140 options[curr_opt++].optionString = argv[arg_idx];
141
142 // Some options require an additional argument.
143 need_extra = false;
144 if (strcmp(argv[arg_idx], "-classpath") == 0 || strcmp(argv[arg_idx], "-cp") == 0) {
145 need_extra = true;
146 what = argv[arg_idx];
147 }
148 }
149
150 if (need_extra) {
151 fprintf(stderr, "%s must be followed by an additional argument giving a value\n", what);
152 return EXIT_FAILURE;
153 }
154
155 if (curr_opt > option_count) {
156 fprintf(stderr, "curr_opt(%d) > option_count(%d)\n", curr_opt, option_count);
157 abort();
158 return EXIT_FAILURE;
159 }
160
161 // Find the JNI_CreateJavaVM implementation.
162 JniInvocation jni_invocation;
163 if (!jni_invocation.Init(lib)) {
164 fprintf(stderr, "Failed to initialize JNI invocation API from %s\n", lib);
165 return EXIT_FAILURE;
166 }
167
168 JavaVMInitArgs init_args;
169 init_args.version = JNI_VERSION_1_6;
170 init_args.options = options.get();
171 init_args.nOptions = curr_opt;
172 init_args.ignoreUnrecognized = JNI_FALSE;
173
174 // Start the runtime. The current thread becomes the main thread.
175 JavaVM* vm = nullptr;
176 JNIEnv* env = nullptr;
177 if (JNI_CreateJavaVM(&vm, &env, &init_args) != JNI_OK) {
178 fprintf(stderr, "Failed to initialize runtime (check log for details)\n");
179 return EXIT_FAILURE;
180 }
181
182 // Make sure they provided a class name. We do this after
183 // JNI_CreateJavaVM so that things like "-help" have the opportunity
184 // to emit a usage statement.
185 if (arg_idx == argc) {
186 fprintf(stderr, "Class name required\n");
187 return EXIT_FAILURE;
188 }
189
190 int rc = InvokeMain(env, &argv[arg_idx]);
191
192 #if defined(NDEBUG)
193 // The DestroyJavaVM call will detach this thread for us. In debug builds, we don't want to
194 // detach because detaching disables the CheckSafeToLockOrUnlock checking.
195 if (vm->DetachCurrentThread() != JNI_OK) {
196 fprintf(stderr, "Warning: unable to detach main thread\n");
197 rc = EXIT_FAILURE;
198 }
199 #endif
200
201 if (vm->DestroyJavaVM() != 0) {
202 fprintf(stderr, "Warning: runtime did not shut down cleanly\n");
203 rc = EXIT_FAILURE;
204 }
205
206 return rc;
207 }
208
209 } // namespace art
210
211 // TODO(b/141622862): stop leaks
__asan_default_options()212 extern "C" const char *__asan_default_options() {
213 return "detect_leaks=0";
214 }
215
main(int argc,char ** argv)216 int main(int argc, char** argv) {
217 // Do not allow static destructors to be called, since it's conceivable that
218 // daemons may still awaken (literally).
219 _exit(art::dalvikvm(argc, argv));
220 }
221