91 lines
2.8 KiB
C
91 lines
2.8 KiB
C
/*
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* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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#include <stdio.h>
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#include <pthread.h>
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#include "jni.h"
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#define STACK_SIZE 0x100000
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/**
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* Attach the current thread with JNI AttachCurrentThread, call a method, and detach.
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*/
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void* thread_main(void* arg) {
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JavaVM *vm;
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JNIEnv *env;
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JavaVMInitArgs vm_args;
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jsize count;
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jint res;
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res = JNI_GetCreatedJavaVMs(&vm, 1, &count);
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if (res != JNI_OK) {
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fprintf(stderr, "JNI_GetCreatedJavaVMs failed: %d\n", res);
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return NULL;
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}
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res = (*vm)->AttachCurrentThread(vm, (void **) &env, NULL);
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if (res != JNI_OK) {
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fprintf(stderr, "AttachCurrentThreadAsDaemon failed: %d\n", res);
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return NULL;
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}
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// call ExplicitAttach.callback()
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jclass clazz = (*env)->FindClass(env, "ExplicitAttach");
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if (clazz == NULL) {
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fprintf(stderr, "FindClass failed\n");
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goto detach;
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}
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jmethodID mid = (*env)->GetStaticMethodID(env, clazz, "callback", "()V");
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if (mid == NULL) {
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fprintf(stderr, "GetStaticMethodID failed\n");
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goto detach;
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}
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(*env)->CallStaticVoidMethod(env, clazz, mid);
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if ((*env)->ExceptionOccurred(env)) {
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fprintf(stderr, "CallStaticVoidMethod failed\n");
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goto detach;
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}
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detach:
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res = (*vm)->DetachCurrentThread(vm);
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if (res != JNI_OK) {
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fprintf(stderr, "DetachCurrentThread failed: %d\n", res);
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}
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return NULL;
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}
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JNIEXPORT void JNICALL Java_ExplicitAttach_startThreads(JNIEnv *env, jclass clazz, int n) {
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pthread_t tid;
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pthread_attr_t attr;
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int i;
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pthread_attr_init(&attr);
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pthread_attr_setstacksize(&attr, STACK_SIZE);
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for (i = 0; i < n ; i++) {
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int res = pthread_create(&tid, &attr, thread_main, NULL);
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if (res != 0) {
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fprintf(stderr, "pthread_create failed: %d\n", res);
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}
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}
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}
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