/* * JNI utility functions * * Copyright (c) 2015-2016 Matthieu Bouron <matthieu.bouron stupeflix.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include <jni.h> #include <pthread.h> #include <stdlib.h> #include "libavutil/bprint.h" #include "libavutil/log.h" #include "config.h" #include "jni.h" #include "ffjni.h" static JavaVM *java_vm; static pthread_key_t current_env; static pthread_once_t once = PTHREAD_ONCE_INIT; static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; static void jni_detach_env(void *data) { if (java_vm) { (*java_vm)->DetachCurrentThread(java_vm); } } static void jni_create_pthread_key(void) { pthread_key_create(¤t_env, jni_detach_env); } JNIEnv *ff_jni_get_env(void *log_ctx) { int ret = 0; JNIEnv *env = NULL; pthread_mutex_lock(&lock); if (java_vm == NULL) { java_vm = av_jni_get_java_vm(log_ctx); } if (!java_vm) { av_log(log_ctx, AV_LOG_ERROR, "No Java virtual machine has been registered\n"); goto done; } pthread_once(&once, jni_create_pthread_key); if ((env = pthread_getspecific(current_env)) != NULL) { goto done; } ret = (*java_vm)->GetEnv(java_vm, (void **)&env, JNI_VERSION_1_6); switch(ret) { case JNI_EDETACHED: if ((*java_vm)->AttachCurrentThread(java_vm, &env, NULL) != 0) { av_log(log_ctx, AV_LOG_ERROR, "Failed to attach the JNI environment to the current thread\n"); env = NULL; } else { pthread_setspecific(current_env, env); } break; case JNI_OK: break; case JNI_EVERSION: av_log(log_ctx, AV_LOG_ERROR, "The specified JNI version is not supported\n"); break; default: av_log(log_ctx, AV_LOG_ERROR, "Failed to get the JNI environment attached to this thread"); break; } done: pthread_mutex_unlock(&lock); return env; } char *ff_jni_jstring_to_utf_chars(JNIEnv *env, jstring string, void *log_ctx) { char *ret = NULL; const char *utf_chars = NULL; jboolean copy = 0; if (!string) { return NULL; } utf_chars = (*env)->GetStringUTFChars(env, string, ©); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "String.getStringUTFChars() threw an exception\n"); return NULL; } ret = av_strdup(utf_chars); (*env)->ReleaseStringUTFChars(env, string, utf_chars); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "String.releaseStringUTFChars() threw an exception\n"); return NULL; } return ret; } jstring ff_jni_utf_chars_to_jstring(JNIEnv *env, const char *utf_chars, void *log_ctx) { jstring ret; ret = (*env)->NewStringUTF(env, utf_chars); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "NewStringUTF() threw an exception\n"); return NULL; } return ret; } int ff_jni_exception_get_summary(JNIEnv *env, jthrowable exception, char **error, void *log_ctx) { int ret = 0; AVBPrint bp; char *name = NULL; char *message = NULL; jclass class_class = NULL; jmethodID get_name_id = NULL; jclass exception_class = NULL; jmethodID get_message_id = NULL; jstring string = NULL; av_bprint_init(&bp, 0, AV_BPRINT_SIZE_AUTOMATIC); exception_class = (*env)->GetObjectClass(env, exception); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Could not find Throwable class\n"); ret = AVERROR_EXTERNAL; goto done; } class_class = (*env)->GetObjectClass(env, exception_class); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Could not find Throwable class's class\n"); ret = AVERROR_EXTERNAL; goto done; } get_name_id = (*env)->GetMethodID(env, class_class, "getName", "()Ljava/lang/String;"); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Could not find method Class.getName()\n"); ret = AVERROR_EXTERNAL; goto done; } string = (*env)->CallObjectMethod(env, exception_class, get_name_id); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Class.getName() threw an exception\n"); ret = AVERROR_EXTERNAL; goto done; } if (string) { name = ff_jni_jstring_to_utf_chars(env, string, log_ctx); (*env)->DeleteLocalRef(env, string); string = NULL; } get_message_id = (*env)->GetMethodID(env, exception_class, "getMessage", "()Ljava/lang/String;"); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Could not find method java/lang/Throwable.getMessage()\n"); ret = AVERROR_EXTERNAL; goto done; } string = (*env)->CallObjectMethod(env, exception, get_message_id); if ((*env)->ExceptionCheck(env)) { (*env)->ExceptionClear(env); av_log(log_ctx, AV_LOG_ERROR, "Throwable.getMessage() threw an exception\n"); ret = AVERROR_EXTERNAL; goto done; } if (string) { message = ff_jni_jstring_to_utf_chars(env, string, log_ctx); (*env)->DeleteLocalRef(env, string); string = NULL; } if (name && message) { av_bprintf(&bp, "%s: %s", name, message); } else if (name && !message) { av_bprintf(&bp, "%s occurred", name); } else if (!name && message) { av_bprintf(&bp, "Exception: %s", message); } else { av_log(log_ctx, AV_LOG_WARNING, "Could not retrieve exception name and message\n"); av_bprintf(&bp, "Exception occurred"); } ret = av_bprint_finalize(&bp, error); done: av_free(name); av_free(message); if (class_class) { (*env)->DeleteLocalRef(env, class_class); } if (exception_class) { (*env)->DeleteLocalRef(env, exception_class); } if (string) { (*env)->DeleteLocalRef(env, string); } return ret; } int ff_jni_exception_check(JNIEnv *env, int log, void *log_ctx) { int ret; jthrowable exception; char *message = NULL; if (!(*(env))->ExceptionCheck((env))) { return 0; } if (!log) { (*(env))->ExceptionClear((env)); return -1; } exception = (*env)->ExceptionOccurred(env); (*(env))->ExceptionClear((env)); if ((ret = ff_jni_exception_get_summary(env, exception, &message, log_ctx)) < 0) { (*env)->DeleteLocalRef(env, exception); return ret; } (*env)->DeleteLocalRef(env, exception); av_log(log_ctx, AV_LOG_ERROR, "%s\n", message); av_free(message); return -1; } int ff_jni_init_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx) { int i, ret = 0; jclass last_clazz = NULL; for (i = 0; jfields_mapping[i].name; i++) { int mandatory = jfields_mapping[i].mandatory; enum FFJniFieldType type = jfields_mapping[i].type; if (type == FF_JNI_CLASS) { jclass clazz; last_clazz = NULL; clazz = (*env)->FindClass(env, jfields_mapping[i].name); if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) { goto done; } last_clazz = *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset) = global ? (*env)->NewGlobalRef(env, clazz) : clazz; } else { if (!last_clazz) { ret = AVERROR_EXTERNAL; break; } switch(type) { case FF_JNI_FIELD: { jfieldID field_id = (*env)->GetFieldID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature); if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) { goto done; } *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = field_id; break; } case FF_JNI_STATIC_FIELD: { jfieldID field_id = (*env)->GetStaticFieldID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature); if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) { goto done; } *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = field_id; break; } case FF_JNI_METHOD: { jmethodID method_id = (*env)->GetMethodID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature); if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) { goto done; } *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = method_id; break; } case FF_JNI_STATIC_METHOD: { jmethodID method_id = (*env)->GetStaticMethodID(env, last_clazz, jfields_mapping[i].method, jfields_mapping[i].signature); if ((ret = ff_jni_exception_check(env, mandatory, log_ctx)) < 0 && mandatory) { goto done; } *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = method_id; break; } default: av_log(log_ctx, AV_LOG_ERROR, "Unknown JNI field type\n"); ret = AVERROR(EINVAL); goto done; } ret = 0; } } done: if (ret < 0) { /* reset jfields in case of failure so it does not leak references */ ff_jni_reset_jfields(env, jfields, jfields_mapping, global, log_ctx); } return ret; } int ff_jni_reset_jfields(JNIEnv *env, void *jfields, const struct FFJniField *jfields_mapping, int global, void *log_ctx) { int i; for (i = 0; jfields_mapping[i].name; i++) { enum FFJniFieldType type = jfields_mapping[i].type; switch(type) { case FF_JNI_CLASS: { jclass clazz = *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset); if (!clazz) continue; if (global) { (*env)->DeleteGlobalRef(env, clazz); } else { (*env)->DeleteLocalRef(env, clazz); } *(jclass*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL; break; } case FF_JNI_FIELD: { *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL; break; } case FF_JNI_STATIC_FIELD: { *(jfieldID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL; break; } case FF_JNI_METHOD: { *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL; break; } case FF_JNI_STATIC_METHOD: { *(jmethodID*)((uint8_t*)jfields + jfields_mapping[i].offset) = NULL; break; } default: av_log(log_ctx, AV_LOG_ERROR, "Unknown JNI field type\n"); } } return 0; }