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/*
* copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <signal.h>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <string>
#include "jni.h"
#include "JniInvocation.h"
#include "ScopedLocalRef.h"
#include "toStringArray.h"
#include "UniquePtr.h"
namespace art {
// Determine whether or not the specified method is public.
static bool IsMethodPublic(JNIEnv* env, jclass c, jmethodID method_id) {
ScopedLocalRef<jobject> reflected(env, env->ToReflectedMethod(c, method_id, JNI_FALSE));
if (reflected.get() == NULL) {
fprintf(stderr, "Failed to get reflected method\n");
return false;
}
// We now have a Method instance. We need to call its
// getModifiers() method.
jclass method_class = env->FindClass("java/lang/reflect/Method");
if (method_class == NULL) {
fprintf(stderr, "Failed to find class java.lang.reflect.Method\n");
return false;
}
jmethodID mid = env->GetMethodID(method_class, "getModifiers", "()I");
if (mid == NULL) {
fprintf(stderr, "Failed to find java.lang.reflect.Method.getModifiers\n");
return false;
}
int modifiers = env->CallIntMethod(reflected.get(), mid);
static const int PUBLIC = 0x0001; // java.lang.reflect.Modifiers.PUBLIC
if ((modifiers & PUBLIC) == 0) {
return false;
}
return true;
}
static int InvokeMain(JNIEnv* env, char** argv) {
// We want to call main() with a String array with our arguments in
// it. Create an array and populate it. Note argv[0] is not
// included.
ScopedLocalRef<jobjectArray> args(env, toStringArray(env, argv + 1));
if (args.get() == NULL) {
env->ExceptionDescribe();
return EXIT_FAILURE;
}
// Find [class].main(String[]).
// Convert "com.android.Blah" to "com/android/Blah".
std::string class_name(argv[0]);
std::replace(class_name.begin(), class_name.end(), '.', '/');
ScopedLocalRef<jclass> klass(env, env->FindClass(class_name.c_str()));
if (klass.get() == NULL) {
fprintf(stderr, "Unable to locate class '%s'\n", class_name.c_str());
env->ExceptionDescribe();
return EXIT_FAILURE;
}
jmethodID method = env->GetStaticMethodID(klass.get(), "main", "([Ljava/lang/String;)V");
if (method == NULL) {
fprintf(stderr, "Unable to find static main(String[]) in '%s'\n", class_name.c_str());
env->ExceptionDescribe();
return EXIT_FAILURE;
}
// Make sure the method is public. JNI doesn't prevent us from
// calling a private method, so we have to check it explicitly.
if (!IsMethodPublic(env, klass.get(), method)) {
fprintf(stderr, "Sorry, main() is not public in '%s'\n", class_name.c_str());
env->ExceptionDescribe();
return EXIT_FAILURE;
}
// Invoke main().
env->CallStaticVoidMethod(klass.get(), method, args.get());
// Check whether there was an uncaught exception. We don't log any uncaught exception here;
// detaching this thread will do that for us, but it will clear the exception (and invalidate
// our JNIEnv), so we need to check here.
return env->ExceptionCheck() ? EXIT_FAILURE : EXIT_SUCCESS;
}
// Parse arguments. Most of it just gets passed through to the runtime.
// The JNI spec defines a handful of standard arguments.
static int dalvikvm(int argc, char** argv) {
setvbuf(stdout, NULL, _IONBF, 0);
// Skip over argv[0].
argv++;
argc--;
// If we're adding any additional stuff, e.g. function hook specifiers,
// add them to the count here.
//
// We're over-allocating, because this includes the options to the runtime
// plus the options to the program.
int option_count = argc;
UniquePtr<JavaVMOption[]> options(new JavaVMOption[option_count]());
// Copy options over. Everything up to the name of the class starts
// with a '-' (the function hook stuff is strictly internal).
//
// [Do we need to catch & handle "-jar" here?]
bool need_extra = false;
const char* lib = NULL;
const char* what = NULL;
int curr_opt, arg_idx;
for (curr_opt = arg_idx = 0; arg_idx < argc; arg_idx++) {
if (argv[arg_idx][0] != '-' && !need_extra) {
break;
}
if (strncmp(argv[arg_idx], "-XXlib:", strlen("-XXlib:")) == 0) {
lib = argv[arg_idx] + strlen("-XXlib:");
continue;
}
options[curr_opt++].optionString = argv[arg_idx];
// Some options require an additional argument.
need_extra = false;
if (strcmp(argv[arg_idx], "-classpath") == 0 || strcmp(argv[arg_idx], "-cp") == 0) {
need_extra = true;
what = argv[arg_idx];
}
}
if (need_extra) {
fprintf(stderr, "%s must be followed by an additional argument giving a value\n", what);
return EXIT_FAILURE;
}
if (curr_opt > option_count) {
fprintf(stderr, "curr_opt(%d) >= option_count(%d)\n", curr_opt, option_count);
abort();
return EXIT_FAILURE;
}
// Find the JNI_CreateJavaVM implementation.
JniInvocation jni_invocation;
if (!jni_invocation.Init(lib)) {
fprintf(stderr, "Failed to initialize JNI invocation API from %s\n", lib);
return EXIT_FAILURE;
}
JavaVMInitArgs init_args;
init_args.version = JNI_VERSION_1_6;
init_args.options = options.get();
init_args.nOptions = curr_opt;
init_args.ignoreUnrecognized = JNI_FALSE;
// Start the runtime. The current thread becomes the main thread.
JavaVM* vm = NULL;
JNIEnv* env = NULL;
if (JNI_CreateJavaVM(&vm, &env, &init_args) != JNI_OK) {
fprintf(stderr, "Failed to initialize runtime (check log for details)\n");
return EXIT_FAILURE;
}
// Make sure they provided a class name. We do this after
// JNI_CreateJavaVM so that things like "-help" have the opportunity
// to emit a usage statement.
if (arg_idx == argc) {
fprintf(stderr, "Class name required\n");
return EXIT_FAILURE;
}
int rc = InvokeMain(env, &argv[arg_idx]);
#if defined(NDEBUG)
// The DestroyJavaVM call will detach this thread for us. In debug builds, we don't want to
// detach because detaching disables the CheckSafeToLockOrUnlock checking.
if (vm->DetachCurrentThread() != JNI_OK) {
fprintf(stderr, "Warning: unable to detach main thread\n");
rc = EXIT_FAILURE;
}
#endif
if (vm->DestroyJavaVM() != 0) {
fprintf(stderr, "Warning: runtime did not shut down cleanly\n");
rc = EXIT_FAILURE;
}
return rc;
}
} // namespace art
int main(int argc, char** argv) {
return art::dalvikvm(argc, argv);
}
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