Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 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 "jni_binder.h" |
| 18 | |
| 19 | #include <dlfcn.h> |
| 20 | #include <inttypes.h> |
| 21 | #include <stdio.h> |
| 22 | |
| 23 | #include "android-base/logging.h" |
| 24 | #include "android-base/stringprintf.h" |
| 25 | |
| 26 | #include "jvmti_helper.h" |
| 27 | #include "scoped_local_ref.h" |
| 28 | #include "scoped_utf_chars.h" |
Andreas Gampe | 027444b | 2017-03-31 12:49:07 -0700 | [diff] [blame] | 29 | #include "ti_utf.h" |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 30 | |
| 31 | namespace art { |
| 32 | |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 33 | static std::string MangleForJni(const std::string& s) { |
| 34 | std::string result; |
Andreas Gampe | 027444b | 2017-03-31 12:49:07 -0700 | [diff] [blame] | 35 | size_t char_count = ti::CountModifiedUtf8Chars(s.c_str(), s.length()); |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 36 | const char* cp = &s[0]; |
| 37 | for (size_t i = 0; i < char_count; ++i) { |
Andreas Gampe | 027444b | 2017-03-31 12:49:07 -0700 | [diff] [blame] | 38 | uint32_t ch = ti::GetUtf16FromUtf8(&cp); |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 39 | if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9')) { |
| 40 | result.push_back(ch); |
| 41 | } else if (ch == '.' || ch == '/') { |
| 42 | result += "_"; |
| 43 | } else if (ch == '_') { |
| 44 | result += "_1"; |
| 45 | } else if (ch == ';') { |
| 46 | result += "_2"; |
| 47 | } else if (ch == '[') { |
| 48 | result += "_3"; |
| 49 | } else { |
Andreas Gampe | 027444b | 2017-03-31 12:49:07 -0700 | [diff] [blame] | 50 | const uint16_t leading = ti::GetLeadingUtf16Char(ch); |
| 51 | const uint32_t trailing = ti::GetTrailingUtf16Char(ch); |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 52 | |
| 53 | android::base::StringAppendF(&result, "_0%04x", leading); |
| 54 | if (trailing != 0) { |
| 55 | android::base::StringAppendF(&result, "_0%04x", trailing); |
| 56 | } |
| 57 | } |
| 58 | } |
| 59 | return result; |
| 60 | } |
| 61 | |
| 62 | static std::string GetJniShortName(const std::string& class_descriptor, const std::string& method) { |
| 63 | // Remove the leading 'L' and trailing ';'... |
| 64 | std::string class_name(class_descriptor); |
| 65 | CHECK_EQ(class_name[0], 'L') << class_name; |
| 66 | CHECK_EQ(class_name[class_name.size() - 1], ';') << class_name; |
| 67 | class_name.erase(0, 1); |
| 68 | class_name.erase(class_name.size() - 1, 1); |
| 69 | |
| 70 | std::string short_name; |
| 71 | short_name += "Java_"; |
| 72 | short_name += MangleForJni(class_name); |
| 73 | short_name += "_"; |
| 74 | short_name += MangleForJni(method); |
| 75 | return short_name; |
| 76 | } |
| 77 | |
| 78 | static void BindMethod(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass, jmethodID method) { |
| 79 | std::string name; |
| 80 | std::string signature; |
| 81 | std::string mangled_names[2]; |
| 82 | { |
| 83 | char* name_cstr; |
| 84 | char* sig_cstr; |
| 85 | jvmtiError name_result = jvmti_env->GetMethodName(method, &name_cstr, &sig_cstr, nullptr); |
| 86 | CheckJvmtiError(jvmti_env, name_result); |
| 87 | CHECK(name_cstr != nullptr); |
| 88 | CHECK(sig_cstr != nullptr); |
| 89 | name = name_cstr; |
| 90 | signature = sig_cstr; |
| 91 | |
| 92 | char* klass_name; |
| 93 | jvmtiError klass_result = jvmti_env->GetClassSignature(klass, &klass_name, nullptr); |
| 94 | CheckJvmtiError(jvmti_env, klass_result); |
| 95 | |
| 96 | mangled_names[0] = GetJniShortName(klass_name, name); |
| 97 | // TODO: Long JNI name. |
| 98 | |
| 99 | CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, name_cstr)); |
| 100 | CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, sig_cstr)); |
| 101 | CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, klass_name)); |
| 102 | } |
| 103 | |
| 104 | for (const std::string& mangled_name : mangled_names) { |
| 105 | if (mangled_name.empty()) { |
| 106 | continue; |
| 107 | } |
| 108 | void* sym = dlsym(RTLD_DEFAULT, mangled_name.c_str()); |
| 109 | if (sym == nullptr) { |
| 110 | continue; |
| 111 | } |
| 112 | |
| 113 | JNINativeMethod native_method; |
| 114 | native_method.fnPtr = sym; |
| 115 | native_method.name = name.c_str(); |
| 116 | native_method.signature = signature.c_str(); |
| 117 | |
| 118 | env->RegisterNatives(klass, &native_method, 1); |
| 119 | |
| 120 | return; |
| 121 | } |
| 122 | |
| 123 | LOG(FATAL) << "Could not find " << mangled_names[0]; |
| 124 | } |
| 125 | |
| 126 | static std::string DescriptorToDot(const char* descriptor) { |
| 127 | size_t length = strlen(descriptor); |
| 128 | if (length > 1) { |
| 129 | if (descriptor[0] == 'L' && descriptor[length - 1] == ';') { |
| 130 | // Descriptors have the leading 'L' and trailing ';' stripped. |
| 131 | std::string result(descriptor + 1, length - 2); |
| 132 | std::replace(result.begin(), result.end(), '/', '.'); |
| 133 | return result; |
| 134 | } else { |
| 135 | // For arrays the 'L' and ';' remain intact. |
| 136 | std::string result(descriptor); |
| 137 | std::replace(result.begin(), result.end(), '/', '.'); |
| 138 | return result; |
| 139 | } |
| 140 | } |
| 141 | // Do nothing for non-class/array descriptors. |
| 142 | return descriptor; |
| 143 | } |
| 144 | |
| 145 | static jobject GetSystemClassLoader(JNIEnv* env) { |
| 146 | ScopedLocalRef<jclass> cl_klass(env, env->FindClass("java/lang/ClassLoader")); |
| 147 | CHECK(cl_klass.get() != nullptr); |
| 148 | jmethodID getsystemclassloader_method = env->GetStaticMethodID(cl_klass.get(), |
| 149 | "getSystemClassLoader", |
| 150 | "()Ljava/lang/ClassLoader;"); |
| 151 | CHECK(getsystemclassloader_method != nullptr); |
| 152 | return env->CallStaticObjectMethod(cl_klass.get(), getsystemclassloader_method); |
| 153 | } |
| 154 | |
| 155 | static jclass FindClassWithClassLoader(JNIEnv* env, const char* class_name, jobject class_loader) { |
| 156 | // Create a String of the name. |
| 157 | std::string descriptor = android::base::StringPrintf("L%s;", class_name); |
| 158 | std::string dot_name = DescriptorToDot(descriptor.c_str()); |
| 159 | ScopedLocalRef<jstring> name_str(env, env->NewStringUTF(dot_name.c_str())); |
| 160 | |
| 161 | // Call Class.forName with it. |
| 162 | ScopedLocalRef<jclass> c_klass(env, env->FindClass("java/lang/Class")); |
| 163 | CHECK(c_klass.get() != nullptr); |
| 164 | jmethodID forname_method = env->GetStaticMethodID( |
| 165 | c_klass.get(), |
| 166 | "forName", |
| 167 | "(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;"); |
| 168 | CHECK(forname_method != nullptr); |
| 169 | |
| 170 | return static_cast<jclass>(env->CallStaticObjectMethod(c_klass.get(), |
| 171 | forname_method, |
| 172 | name_str.get(), |
| 173 | JNI_FALSE, |
| 174 | class_loader)); |
| 175 | } |
| 176 | |
Andreas Gampe | 7a4873e | 2017-04-10 21:09:13 -0700 | [diff] [blame] | 177 | jclass FindClass(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) { |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 178 | if (class_loader != nullptr) { |
| 179 | return FindClassWithClassLoader(env, class_name, class_loader); |
| 180 | } |
| 181 | |
| 182 | jclass from_implied = env->FindClass(class_name); |
| 183 | if (from_implied != nullptr) { |
| 184 | return from_implied; |
| 185 | } |
| 186 | env->ExceptionClear(); |
| 187 | |
| 188 | ScopedLocalRef<jobject> system_class_loader(env, GetSystemClassLoader(env)); |
| 189 | CHECK(system_class_loader.get() != nullptr); |
| 190 | jclass from_system = FindClassWithClassLoader(env, class_name, system_class_loader.get()); |
| 191 | if (from_system != nullptr) { |
| 192 | return from_system; |
| 193 | } |
| 194 | env->ExceptionClear(); |
| 195 | |
| 196 | // Look at the context classloaders of all threads. |
| 197 | jint thread_count; |
| 198 | jthread* threads; |
| 199 | CheckJvmtiError(jvmti_env, jvmti_env->GetAllThreads(&thread_count, &threads)); |
| 200 | JvmtiUniquePtr threads_uptr = MakeJvmtiUniquePtr(jvmti_env, threads); |
| 201 | |
| 202 | jclass result = nullptr; |
| 203 | for (jint t = 0; t != thread_count; ++t) { |
| 204 | // Always loop over all elements, as we need to free the local references. |
| 205 | if (result == nullptr) { |
| 206 | jvmtiThreadInfo info; |
| 207 | CheckJvmtiError(jvmti_env, jvmti_env->GetThreadInfo(threads[t], &info)); |
| 208 | CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, info.name)); |
| 209 | if (info.thread_group != nullptr) { |
| 210 | env->DeleteLocalRef(info.thread_group); |
| 211 | } |
| 212 | if (info.context_class_loader != nullptr) { |
| 213 | result = FindClassWithClassLoader(env, class_name, info.context_class_loader); |
| 214 | env->ExceptionClear(); |
| 215 | env->DeleteLocalRef(info.context_class_loader); |
| 216 | } |
| 217 | } |
| 218 | env->DeleteLocalRef(threads[t]); |
| 219 | } |
| 220 | |
| 221 | if (result != nullptr) { |
| 222 | return result; |
| 223 | } |
| 224 | |
| 225 | // TODO: Implement scanning *all* classloaders. |
Jesse Schettler | 7cac35f | 2018-10-05 09:37:04 -0600 | [diff] [blame] | 226 | LOG(WARNING) << "Scanning all classloaders unimplemented"; |
Andreas Gampe | 3f46c96 | 2017-03-30 10:26:59 -0700 | [diff] [blame] | 227 | |
| 228 | return nullptr; |
| 229 | } |
| 230 | |
| 231 | void BindFunctionsOnClass(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass) { |
| 232 | // Use JVMTI to get the methods. |
| 233 | jint method_count; |
| 234 | jmethodID* methods; |
| 235 | jvmtiError methods_result = jvmti_env->GetClassMethods(klass, &method_count, &methods); |
| 236 | CheckJvmtiError(jvmti_env, methods_result); |
| 237 | |
| 238 | // Check each method. |
| 239 | for (jint i = 0; i < method_count; ++i) { |
| 240 | jint modifiers; |
| 241 | jvmtiError mod_result = jvmti_env->GetMethodModifiers(methods[i], &modifiers); |
| 242 | CheckJvmtiError(jvmti_env, mod_result); |
| 243 | constexpr jint kNative = static_cast<jint>(0x0100); |
| 244 | if ((modifiers & kNative) != 0) { |
| 245 | BindMethod(jvmti_env, env, klass, methods[i]); |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, methods)); |
| 250 | } |
| 251 | |
| 252 | void BindFunctions(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) { |
| 253 | // Use JNI to load the class. |
| 254 | ScopedLocalRef<jclass> klass(env, FindClass(jvmti_env, env, class_name, class_loader)); |
| 255 | CHECK(klass.get() != nullptr) << class_name; |
| 256 | BindFunctionsOnClass(jvmti_env, env, klass.get()); |
| 257 | } |
| 258 | |
| 259 | } // namespace art |