| /* |
| * Copyright (C) 2006 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. |
| */ |
| |
| #define LOG_TAG "JNIHelp" |
| |
| #include "nativehelper/JNIHelp.h" |
| |
| #include "ALog-priv.h" |
| |
| #include <string> |
| |
| #include "JniConstants.h" |
| #include "nativehelper/ScopedLocalRef.h" |
| |
| /** |
| * Equivalent to ScopedLocalRef, but for C_JNIEnv instead. (And slightly more powerful.) |
| */ |
| template<typename T> |
| class scoped_local_ref { |
| public: |
| explicit scoped_local_ref(C_JNIEnv* env, T localRef = NULL) |
| : mEnv(env), mLocalRef(localRef) |
| { |
| } |
| |
| ~scoped_local_ref() { |
| reset(); |
| } |
| |
| void reset(T localRef = NULL) { |
| if (mLocalRef != NULL) { |
| (*mEnv)->DeleteLocalRef(reinterpret_cast<JNIEnv*>(mEnv), mLocalRef); |
| mLocalRef = localRef; |
| } |
| } |
| |
| T get() const { |
| return mLocalRef; |
| } |
| |
| private: |
| C_JNIEnv* const mEnv; |
| T mLocalRef; |
| |
| DISALLOW_COPY_AND_ASSIGN(scoped_local_ref); |
| }; |
| |
| static jclass findClass(C_JNIEnv* env, const char* className) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| return (*env)->FindClass(e, className); |
| } |
| |
| MODULE_API int jniRegisterNativeMethods(C_JNIEnv* env, const char* className, |
| const JNINativeMethod* gMethods, int numMethods) |
| { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| |
| ALOGV("Registering %s's %d native methods...", className, numMethods); |
| |
| scoped_local_ref<jclass> c(env, findClass(env, className)); |
| ALOG_ALWAYS_FATAL_IF(c.get() == NULL, |
| "Native registration unable to find class '%s'; aborting...", |
| className); |
| |
| int result = e->RegisterNatives(c.get(), gMethods, numMethods); |
| ALOG_ALWAYS_FATAL_IF(result < 0, "RegisterNatives failed for '%s'; aborting...", |
| className); |
| |
| return 0; |
| } |
| |
| /* |
| * Returns a human-readable summary of an exception object. The buffer will |
| * be populated with the "binary" class name and, if present, the |
| * exception message. |
| */ |
| static bool getExceptionSummary(C_JNIEnv* env, jthrowable exception, std::string& result) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| |
| /* get the name of the exception's class */ |
| scoped_local_ref<jclass> exceptionClass(env, (*env)->GetObjectClass(e, exception)); // can't fail |
| scoped_local_ref<jclass> classClass(env, |
| (*env)->GetObjectClass(e, exceptionClass.get())); // java.lang.Class, can't fail |
| jmethodID classGetNameMethod = |
| (*env)->GetMethodID(e, classClass.get(), "getName", "()Ljava/lang/String;"); |
| scoped_local_ref<jstring> classNameStr(env, |
| (jstring) (*env)->CallObjectMethod(e, exceptionClass.get(), classGetNameMethod)); |
| if (classNameStr.get() == NULL) { |
| (*env)->ExceptionClear(e); |
| result = "<error getting class name>"; |
| return false; |
| } |
| const char* classNameChars = (*env)->GetStringUTFChars(e, classNameStr.get(), NULL); |
| if (classNameChars == NULL) { |
| (*env)->ExceptionClear(e); |
| result = "<error getting class name UTF-8>"; |
| return false; |
| } |
| result += classNameChars; |
| (*env)->ReleaseStringUTFChars(e, classNameStr.get(), classNameChars); |
| |
| /* if the exception has a detail message, get that */ |
| jmethodID getMessage = |
| (*env)->GetMethodID(e, exceptionClass.get(), "getMessage", "()Ljava/lang/String;"); |
| scoped_local_ref<jstring> messageStr(env, |
| (jstring) (*env)->CallObjectMethod(e, exception, getMessage)); |
| if (messageStr.get() == NULL) { |
| return true; |
| } |
| |
| result += ": "; |
| |
| const char* messageChars = (*env)->GetStringUTFChars(e, messageStr.get(), NULL); |
| if (messageChars != NULL) { |
| result += messageChars; |
| (*env)->ReleaseStringUTFChars(e, messageStr.get(), messageChars); |
| } else { |
| result += "<error getting message>"; |
| (*env)->ExceptionClear(e); // clear OOM |
| } |
| |
| return true; |
| } |
| |
| /* |
| * Returns an exception (with stack trace) as a string. |
| */ |
| static bool getStackTrace(C_JNIEnv* env, jthrowable exception, std::string& result) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| |
| scoped_local_ref<jclass> stringWriterClass(env, findClass(env, "java/io/StringWriter")); |
| if (stringWriterClass.get() == NULL) { |
| return false; |
| } |
| |
| jmethodID stringWriterCtor = (*env)->GetMethodID(e, stringWriterClass.get(), "<init>", "()V"); |
| jmethodID stringWriterToStringMethod = |
| (*env)->GetMethodID(e, stringWriterClass.get(), "toString", "()Ljava/lang/String;"); |
| |
| scoped_local_ref<jclass> printWriterClass(env, findClass(env, "java/io/PrintWriter")); |
| if (printWriterClass.get() == NULL) { |
| return false; |
| } |
| |
| jmethodID printWriterCtor = |
| (*env)->GetMethodID(e, printWriterClass.get(), "<init>", "(Ljava/io/Writer;)V"); |
| |
| scoped_local_ref<jobject> stringWriter(env, |
| (*env)->NewObject(e, stringWriterClass.get(), stringWriterCtor)); |
| if (stringWriter.get() == NULL) { |
| return false; |
| } |
| |
| scoped_local_ref<jobject> printWriter(env, |
| (*env)->NewObject(e, printWriterClass.get(), printWriterCtor, stringWriter.get())); |
| if (printWriter.get() == NULL) { |
| return false; |
| } |
| |
| scoped_local_ref<jclass> exceptionClass(env, (*env)->GetObjectClass(e, exception)); // can't fail |
| jmethodID printStackTraceMethod = |
| (*env)->GetMethodID(e, exceptionClass.get(), "printStackTrace", "(Ljava/io/PrintWriter;)V"); |
| (*env)->CallVoidMethod(e, exception, printStackTraceMethod, printWriter.get()); |
| |
| if ((*env)->ExceptionCheck(e)) { |
| return false; |
| } |
| |
| scoped_local_ref<jstring> messageStr(env, |
| (jstring) (*env)->CallObjectMethod(e, stringWriter.get(), stringWriterToStringMethod)); |
| if (messageStr.get() == NULL) { |
| return false; |
| } |
| |
| const char* utfChars = (*env)->GetStringUTFChars(e, messageStr.get(), NULL); |
| if (utfChars == NULL) { |
| return false; |
| } |
| |
| result = utfChars; |
| |
| (*env)->ReleaseStringUTFChars(e, messageStr.get(), utfChars); |
| return true; |
| } |
| |
| MODULE_API int jniThrowException(C_JNIEnv* env, const char* className, const char* msg) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| |
| if ((*env)->ExceptionCheck(e)) { |
| /* TODO: consider creating the new exception with this as "cause" */ |
| scoped_local_ref<jthrowable> exception(env, (*env)->ExceptionOccurred(e)); |
| (*env)->ExceptionClear(e); |
| |
| if (exception.get() != NULL) { |
| std::string text; |
| getExceptionSummary(env, exception.get(), text); |
| ALOGW("Discarding pending exception (%s) to throw %s", text.c_str(), className); |
| } |
| } |
| |
| scoped_local_ref<jclass> exceptionClass(env, findClass(env, className)); |
| if (exceptionClass.get() == NULL) { |
| ALOGE("Unable to find exception class %s", className); |
| /* ClassNotFoundException now pending */ |
| return -1; |
| } |
| |
| if ((*env)->ThrowNew(e, exceptionClass.get(), msg) != JNI_OK) { |
| ALOGE("Failed throwing '%s' '%s'", className, msg); |
| /* an exception, most likely OOM, will now be pending */ |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| MODULE_API int jniThrowExceptionFmt(C_JNIEnv* env, const char* className, const char* fmt, va_list args) { |
| char msgBuf[512]; |
| vsnprintf(msgBuf, sizeof(msgBuf), fmt, args); |
| return jniThrowException(env, className, msgBuf); |
| } |
| |
| MODULE_API int jniThrowNullPointerException(C_JNIEnv* env, const char* msg) { |
| return jniThrowException(env, "java/lang/NullPointerException", msg); |
| } |
| |
| MODULE_API int jniThrowRuntimeException(C_JNIEnv* env, const char* msg) { |
| return jniThrowException(env, "java/lang/RuntimeException", msg); |
| } |
| |
| MODULE_API int jniThrowIOException(C_JNIEnv* env, int errnum) { |
| char buffer[80]; |
| const char* message = jniStrError(errnum, buffer, sizeof(buffer)); |
| return jniThrowException(env, "java/io/IOException", message); |
| } |
| |
| static std::string jniGetStackTrace(C_JNIEnv* env, jthrowable exception) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| |
| scoped_local_ref<jthrowable> currentException(env, (*env)->ExceptionOccurred(e)); |
| if (exception == NULL) { |
| exception = currentException.get(); |
| if (exception == NULL) { |
| return "<no pending exception>"; |
| } |
| } |
| |
| if (currentException.get() != NULL) { |
| (*env)->ExceptionClear(e); |
| } |
| |
| std::string trace; |
| if (!getStackTrace(env, exception, trace)) { |
| (*env)->ExceptionClear(e); |
| getExceptionSummary(env, exception, trace); |
| } |
| |
| if (currentException.get() != NULL) { |
| (*env)->Throw(e, currentException.get()); // rethrow |
| } |
| |
| return trace; |
| } |
| |
| MODULE_API void jniLogException(C_JNIEnv* env, int priority, const char* tag, jthrowable exception) { |
| std::string trace(jniGetStackTrace(env, exception)); |
| __android_log_write(priority, tag, trace.c_str()); |
| } |
| |
| // Note: glibc has a nonstandard strerror_r that returns char* rather than POSIX's int. |
| // char *strerror_r(int errnum, char *buf, size_t n); |
| // |
| // Some versions of bionic support the glibc style call. Since the set of defines that determine |
| // which version is used is byzantine in its complexity we will just use this C++ template hack to |
| // select the correct jniStrError implementation based on the libc being used. |
| namespace impl { |
| |
| using GNUStrError = char* (*)(int,char*,size_t); |
| using POSIXStrError = int (*)(int,char*,size_t); |
| |
| inline const char* realJniStrError(GNUStrError func, int errnum, char* buf, size_t buflen) { |
| return func(errnum, buf, buflen); |
| } |
| |
| inline const char* realJniStrError(POSIXStrError func, int errnum, char* buf, size_t buflen) { |
| int rc = func(errnum, buf, buflen); |
| if (rc != 0) { |
| // (POSIX only guarantees a value other than 0. The safest |
| // way to implement this function is to use C++ and overload on the |
| // type of strerror_r to accurately distinguish GNU from POSIX.) |
| snprintf(buf, buflen, "errno %d", errnum); |
| } |
| return buf; |
| } |
| |
| } // namespace impl |
| |
| MODULE_API const char* jniStrError(int errnum, char* buf, size_t buflen) { |
| #ifdef _WIN32 |
| strerror_s(buf, buflen, errnum); |
| return buf; |
| #else |
| // The magic of C++ overloading selects the correct implementation based on the declared type of |
| // strerror_r. The inline will ensure that we don't have any indirect calls. |
| return impl::realJniStrError(strerror_r, errnum, buf, buflen); |
| #endif |
| } |
| |
| MODULE_API jobject jniCreateFileDescriptor(C_JNIEnv* env, int fd) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| jobject fileDescriptor = e->NewObject(JniConstants::GetFileDescriptorClass(e), |
| JniConstants::GetFileDescriptorInitMethod(e)); |
| // NOTE: NewObject ensures that an OutOfMemoryError will be seen by the Java |
| // caller if the alloc fails, so we just return nullptr when that happens. |
| if (fileDescriptor != nullptr) { |
| jniSetFileDescriptorOfFD(env, fileDescriptor, fd); |
| } |
| return fileDescriptor; |
| } |
| |
| MODULE_API int jniGetFDFromFileDescriptor(C_JNIEnv* env, jobject fileDescriptor) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| if (fileDescriptor != nullptr) { |
| return e->GetIntField(fileDescriptor, |
| JniConstants::GetFileDescriptorDescriptorField(e)); |
| } else { |
| return -1; |
| } |
| } |
| |
| MODULE_API void jniSetFileDescriptorOfFD(C_JNIEnv* env, jobject fileDescriptor, int value) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| if (fileDescriptor == nullptr) { |
| jniThrowNullPointerException(e, "null FileDescriptor"); |
| } else { |
| e->SetIntField(fileDescriptor, JniConstants::GetFileDescriptorDescriptorField(e), value); |
| } |
| } |
| |
| MODULE_API jlong jniGetOwnerIdFromFileDescriptor(C_JNIEnv* env, jobject fileDescriptor) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| return e->GetLongField(fileDescriptor, JniConstants::GetFileDescriptorOwnerIdField(e)); |
| } |
| |
| MODULE_API jobject jniGetReferent(C_JNIEnv* env, jobject ref) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| return e->CallObjectMethod(ref, JniConstants::GetReferenceGetMethod(e)); |
| } |
| |
| MODULE_API jstring jniCreateString(C_JNIEnv* env, const jchar* unicodeChars, jsize len) { |
| JNIEnv* e = reinterpret_cast<JNIEnv*>(env); |
| return e->NewString(unicodeChars, len); |
| } |