test/ti-agent/jni_binder.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2017 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 "jni_binder.h"

 #include <dlfcn.h>
 #include <inttypes.h>
 #include <stdio.h>

 #include "android-base/logging.h"
 #include "android-base/stringprintf.h"

 #include "jvmti_helper.h"
 #include "scoped_local_ref.h"
 #include "scoped_utf_chars.h"
 #include "ti_utf.h"

 namespace art {

 static std::string MangleForJni(const std::string& s) {
   std::string result;
   size_t char_count = ti::CountModifiedUtf8Chars(s.c_str(), s.length());
   const char* cp = &s[0];
   for (size_t i = 0; i < char_count; ++i) {
     uint32_t ch = ti::GetUtf16FromUtf8(&cp);
     if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9')) {
       result.push_back(ch);
     } else if (ch == '.' || ch == '/') {
       result += "_";
     } else if (ch == '_') {
       result += "_1";
     } else if (ch == ';') {
       result += "_2";
     } else if (ch == '[') {
       result += "_3";
     } else {
       const uint16_t leading = ti::GetLeadingUtf16Char(ch);
       const uint32_t trailing = ti::GetTrailingUtf16Char(ch);

       android::base::StringAppendF(&result, "_0%04x", leading);
       if (trailing != 0) {
         android::base::StringAppendF(&result, "_0%04x", trailing);
       }
     }
   }
   return result;
 }

 static std::string GetJniShortName(const std::string& class_descriptor, const std::string& method) {
   // Remove the leading 'L' and trailing ';'...
   std::string class_name(class_descriptor);
   CHECK_EQ(class_name[0], 'L') << class_name;
   CHECK_EQ(class_name[class_name.size() - 1], ';') << class_name;
   class_name.erase(0, 1);
   class_name.erase(class_name.size() - 1, 1);

   std::string short_name;
   short_name += "Java_";
   short_name += MangleForJni(class_name);
   short_name += "_";
   short_name += MangleForJni(method);
   return short_name;
 }

 static void BindMethod(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass, jmethodID method) {
   std::string name;
   std::string signature;
   std::string mangled_names[2];
   {
     char* name_cstr;
     char* sig_cstr;
     jvmtiError name_result = jvmti_env->GetMethodName(method, &name_cstr, &sig_cstr, nullptr);
     CheckJvmtiError(jvmti_env, name_result);
     CHECK(name_cstr != nullptr);
     CHECK(sig_cstr != nullptr);
     name = name_cstr;
     signature = sig_cstr;

     char* klass_name;
     jvmtiError klass_result = jvmti_env->GetClassSignature(klass, &klass_name, nullptr);
     CheckJvmtiError(jvmti_env, klass_result);

     mangled_names[0] = GetJniShortName(klass_name, name);
     // TODO: Long JNI name.

     CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, name_cstr));
     CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, sig_cstr));
     CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, klass_name));
   }

   for (const std::string& mangled_name : mangled_names) {
     if (mangled_name.empty()) {
       continue;
     }
     void* sym = dlsym(RTLD_DEFAULT, mangled_name.c_str());
     if (sym == nullptr) {
       continue;
     }

     JNINativeMethod native_method;
     native_method.fnPtr = sym;
     native_method.name = name.c_str();
     native_method.signature = signature.c_str();

     env->RegisterNatives(klass, &native_method, 1);

     return;
   }

   LOG(FATAL) << "Could not find " << mangled_names[0];
 }

 static std::string DescriptorToDot(const char* descriptor) {
   size_t length = strlen(descriptor);
   if (length > 1) {
     if (descriptor[0] == 'L' && descriptor[length - 1] == ';') {
       // Descriptors have the leading 'L' and trailing ';' stripped.
       std::string result(descriptor + 1, length - 2);
       std::replace(result.begin(), result.end(), '/', '.');
       return result;
     } else {
       // For arrays the 'L' and ';' remain intact.
       std::string result(descriptor);
       std::replace(result.begin(), result.end(), '/', '.');
       return result;
     }
   }
   // Do nothing for non-class/array descriptors.
   return descriptor;
 }

 static jobject GetSystemClassLoader(JNIEnv* env) {
   ScopedLocalRef<jclass> cl_klass(env, env->FindClass("java/lang/ClassLoader"));
   CHECK(cl_klass.get() != nullptr);
   jmethodID getsystemclassloader_method = env->GetStaticMethodID(cl_klass.get(),
                                                                  "getSystemClassLoader",
                                                                  "()Ljava/lang/ClassLoader;");
   CHECK(getsystemclassloader_method != nullptr);
   return env->CallStaticObjectMethod(cl_klass.get(), getsystemclassloader_method);
 }

 static jclass FindClassWithClassLoader(JNIEnv* env, const char* class_name, jobject class_loader) {
   // Create a String of the name.
   std::string descriptor = android::base::StringPrintf("L%s;", class_name);
   std::string dot_name = DescriptorToDot(descriptor.c_str());
   ScopedLocalRef<jstring> name_str(env, env->NewStringUTF(dot_name.c_str()));

   // Call Class.forName with it.
   ScopedLocalRef<jclass> c_klass(env, env->FindClass("java/lang/Class"));
   CHECK(c_klass.get() != nullptr);
   jmethodID forname_method = env->GetStaticMethodID(
       c_klass.get(),
       "forName",
       "(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;");
   CHECK(forname_method != nullptr);

   return static_cast<jclass>(env->CallStaticObjectMethod(c_klass.get(),
                                                          forname_method,
                                                          name_str.get(),
                                                          JNI_FALSE,
                                                          class_loader));
 }

 jclass GetClass(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) {
   if (class_loader != nullptr) {
     return FindClassWithClassLoader(env, class_name, class_loader);
   }

   jclass from_implied = env->FindClass(class_name);
   if (from_implied != nullptr) {
     return from_implied;
   }
   env->ExceptionClear();

   ScopedLocalRef<jobject> system_class_loader(env, GetSystemClassLoader(env));
   CHECK(system_class_loader.get() != nullptr);
   jclass from_system = FindClassWithClassLoader(env, class_name, system_class_loader.get());
   if (from_system != nullptr) {
     return from_system;
   }
   env->ExceptionClear();

   // Look at the context classloaders of all threads.
   jint thread_count;
   jthread* threads;
   CheckJvmtiError(jvmti_env, jvmti_env->GetAllThreads(&thread_count, &threads));
   JvmtiUniquePtr threads_uptr = MakeJvmtiUniquePtr(jvmti_env, threads);

   jclass result = nullptr;
   for (jint t = 0; t != thread_count; ++t) {
     // Always loop over all elements, as we need to free the local references.
     if (result == nullptr) {
       jvmtiThreadInfo info;
       CheckJvmtiError(jvmti_env, jvmti_env->GetThreadInfo(threads[t], &info));
       CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, info.name));
       if (info.thread_group != nullptr) {
         env->DeleteLocalRef(info.thread_group);
       }
       if (info.context_class_loader != nullptr) {
         result = FindClassWithClassLoader(env, class_name, info.context_class_loader);
         env->ExceptionClear();
         env->DeleteLocalRef(info.context_class_loader);
       }
     }
     env->DeleteLocalRef(threads[t]);
   }

   if (result != nullptr) {
     return result;
   }

   // TODO: Implement scanning *all* classloaders.
   LOG(WARNING) << "Scanning all classloaders unimplemented";

   return nullptr;
 }

 void BindFunctionsOnClass(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass) {
   // Use JVMTI to get the methods.
   jint method_count;
   jmethodID* methods;
   jvmtiError methods_result = jvmti_env->GetClassMethods(klass, &method_count, &methods);
   CheckJvmtiError(jvmti_env, methods_result);

   // Check each method.
   for (jint i = 0; i < method_count; ++i) {
     jint modifiers;
     jvmtiError mod_result = jvmti_env->GetMethodModifiers(methods[i], &modifiers);
     CheckJvmtiError(jvmti_env, mod_result);
     constexpr jint kNative = static_cast<jint>(0x0100);
     if ((modifiers & kNative) != 0) {
       BindMethod(jvmti_env, env, klass, methods[i]);
     }
   }

   CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, methods));
 }

 void BindFunctions(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) {
   // Use JNI to load the class.
   ScopedLocalRef<jclass> klass(env, GetClass(jvmti_env, env, class_name, class_loader));
   CHECK(klass.get() != nullptr) << class_name;
   BindFunctionsOnClass(jvmti_env, env, klass.get());
 }

 }  // namespace art
	/*
	* Copyright (C) 2017 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 "jni_binder.h"

	#include <dlfcn.h>
	#include <inttypes.h>
	#include <stdio.h>

	#include "android-base/logging.h"
	#include "android-base/stringprintf.h"

	#include "jvmti_helper.h"
	#include "scoped_local_ref.h"
	#include "scoped_utf_chars.h"
	#include "ti_utf.h"

	namespace art {

	static std::string MangleForJni(const std::string& s) {
	std::string result;
	size_t char_count = ti::CountModifiedUtf8Chars(s.c_str(), s.length());
	const char* cp = &s[0];
	for (size_t i = 0; i < char_count; ++i) {
	uint32_t ch = ti::GetUtf16FromUtf8(&cp);
	if ((ch >= 'A' && ch <= 'Z') \|\| (ch >= 'a' && ch <= 'z') \|\| (ch >= '0' && ch <= '9')) {
	result.push_back(ch);
	} else if (ch == '.' \|\| ch == '/') {
	result += "_";
	} else if (ch == '_') {
	result += "_1";
	} else if (ch == ';') {
	result += "_2";
	} else if (ch == '[') {
	result += "_3";
	} else {
	const uint16_t leading = ti::GetLeadingUtf16Char(ch);
	const uint32_t trailing = ti::GetTrailingUtf16Char(ch);

	android::base::StringAppendF(&result, "_0%04x", leading);
	if (trailing != 0) {
	android::base::StringAppendF(&result, "_0%04x", trailing);
	}
	}
	}
	return result;
	}

	static std::string GetJniShortName(const std::string& class_descriptor, const std::string& method) {
	// Remove the leading 'L' and trailing ';'...
	std::string class_name(class_descriptor);
	CHECK_EQ(class_name[0], 'L') << class_name;
	CHECK_EQ(class_name[class_name.size() - 1], ';') << class_name;
	class_name.erase(0, 1);
	class_name.erase(class_name.size() - 1, 1);

	std::string short_name;
	short_name += "Java_";
	short_name += MangleForJni(class_name);
	short_name += "_";
	short_name += MangleForJni(method);
	return short_name;
	}

	static void BindMethod(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass, jmethodID method) {
	std::string name;
	std::string signature;
	std::string mangled_names[2];
	{
	char* name_cstr;
	char* sig_cstr;
	jvmtiError name_result = jvmti_env->GetMethodName(method, &name_cstr, &sig_cstr, nullptr);
	CheckJvmtiError(jvmti_env, name_result);
	CHECK(name_cstr != nullptr);
	CHECK(sig_cstr != nullptr);
	name = name_cstr;
	signature = sig_cstr;

	char* klass_name;
	jvmtiError klass_result = jvmti_env->GetClassSignature(klass, &klass_name, nullptr);
	CheckJvmtiError(jvmti_env, klass_result);

	mangled_names[0] = GetJniShortName(klass_name, name);
	// TODO: Long JNI name.

	CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, name_cstr));
	CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, sig_cstr));
	CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, klass_name));
	}

	for (const std::string& mangled_name : mangled_names) {
	if (mangled_name.empty()) {
	continue;
	}
	void* sym = dlsym(RTLD_DEFAULT, mangled_name.c_str());
	if (sym == nullptr) {
	continue;
	}

	JNINativeMethod native_method;
	native_method.fnPtr = sym;
	native_method.name = name.c_str();
	native_method.signature = signature.c_str();

	env->RegisterNatives(klass, &native_method, 1);

	return;
	}

	LOG(FATAL) << "Could not find " << mangled_names[0];
	}

	static std::string DescriptorToDot(const char* descriptor) {
	size_t length = strlen(descriptor);
	if (length > 1) {
	if (descriptor[0] == 'L' && descriptor[length - 1] == ';') {
	// Descriptors have the leading 'L' and trailing ';' stripped.
	std::string result(descriptor + 1, length - 2);
	std::replace(result.begin(), result.end(), '/', '.');
	return result;
	} else {
	// For arrays the 'L' and ';' remain intact.
	std::string result(descriptor);
	std::replace(result.begin(), result.end(), '/', '.');
	return result;
	}
	}
	// Do nothing for non-class/array descriptors.
	return descriptor;
	}

	static jobject GetSystemClassLoader(JNIEnv* env) {
	ScopedLocalRef<jclass> cl_klass(env, env->FindClass("java/lang/ClassLoader"));
	CHECK(cl_klass.get() != nullptr);
	jmethodID getsystemclassloader_method = env->GetStaticMethodID(cl_klass.get(),
	"getSystemClassLoader",
	"()Ljava/lang/ClassLoader;");
	CHECK(getsystemclassloader_method != nullptr);
	return env->CallStaticObjectMethod(cl_klass.get(), getsystemclassloader_method);
	}

	static jclass FindClassWithClassLoader(JNIEnv* env, const char* class_name, jobject class_loader) {
	// Create a String of the name.
	std::string descriptor = android::base::StringPrintf("L%s;", class_name);
	std::string dot_name = DescriptorToDot(descriptor.c_str());
	ScopedLocalRef<jstring> name_str(env, env->NewStringUTF(dot_name.c_str()));

	// Call Class.forName with it.
	ScopedLocalRef<jclass> c_klass(env, env->FindClass("java/lang/Class"));
	CHECK(c_klass.get() != nullptr);
	jmethodID forname_method = env->GetStaticMethodID(
	c_klass.get(),
	"forName",
	"(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;");
	CHECK(forname_method != nullptr);

	return static_cast<jclass>(env->CallStaticObjectMethod(c_klass.get(),
	forname_method,
	name_str.get(),
	JNI_FALSE,
	class_loader));
	}

	jclass GetClass(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) {
	if (class_loader != nullptr) {
	return FindClassWithClassLoader(env, class_name, class_loader);
	}

	jclass from_implied = env->FindClass(class_name);
	if (from_implied != nullptr) {
	return from_implied;
	}
	env->ExceptionClear();

	ScopedLocalRef<jobject> system_class_loader(env, GetSystemClassLoader(env));
	CHECK(system_class_loader.get() != nullptr);
	jclass from_system = FindClassWithClassLoader(env, class_name, system_class_loader.get());
	if (from_system != nullptr) {
	return from_system;
	}
	env->ExceptionClear();

	// Look at the context classloaders of all threads.
	jint thread_count;
	jthread* threads;
	CheckJvmtiError(jvmti_env, jvmti_env->GetAllThreads(&thread_count, &threads));
	JvmtiUniquePtr threads_uptr = MakeJvmtiUniquePtr(jvmti_env, threads);

	jclass result = nullptr;
	for (jint t = 0; t != thread_count; ++t) {
	// Always loop over all elements, as we need to free the local references.
	if (result == nullptr) {
	jvmtiThreadInfo info;
	CheckJvmtiError(jvmti_env, jvmti_env->GetThreadInfo(threads[t], &info));
	CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, info.name));
	if (info.thread_group != nullptr) {
	env->DeleteLocalRef(info.thread_group);
	}
	if (info.context_class_loader != nullptr) {
	result = FindClassWithClassLoader(env, class_name, info.context_class_loader);
	env->ExceptionClear();
	env->DeleteLocalRef(info.context_class_loader);
	}
	}
	env->DeleteLocalRef(threads[t]);
	}

	if (result != nullptr) {
	return result;
	}

	// TODO: Implement scanning all classloaders.
	LOG(WARNING) << "Scanning all classloaders unimplemented";

	return nullptr;
	}

	void BindFunctionsOnClass(jvmtiEnv* jvmti_env, JNIEnv* env, jclass klass) {
	// Use JVMTI to get the methods.
	jint method_count;
	jmethodID* methods;
	jvmtiError methods_result = jvmti_env->GetClassMethods(klass, &method_count, &methods);
	CheckJvmtiError(jvmti_env, methods_result);

	// Check each method.
	for (jint i = 0; i < method_count; ++i) {
	jint modifiers;
	jvmtiError mod_result = jvmti_env->GetMethodModifiers(methods[i], &modifiers);
	CheckJvmtiError(jvmti_env, mod_result);
	constexpr jint kNative = static_cast<jint>(0x0100);
	if ((modifiers & kNative) != 0) {
	BindMethod(jvmti_env, env, klass, methods[i]);
	}
	}

	CheckJvmtiError(jvmti_env, Deallocate(jvmti_env, methods));
	}

	void BindFunctions(jvmtiEnv* jvmti_env, JNIEnv* env, const char* class_name, jobject class_loader) {
	// Use JNI to load the class.
	ScopedLocalRef<jclass> klass(env, GetClass(jvmti_env, env, class_name, class_loader));
	CHECK(klass.get() != nullptr) << class_name;
	BindFunctionsOnClass(jvmti_env, env, klass.get());
	}

	} // namespace art