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/*
* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* Test if a file exists in the file system cache
*/
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/mman.h>
#include "jni.h"
/*
* Throws an exception with the given class name and detail message
*/
static void ThrowException(JNIEnv *env, const char *name, const char *msg) {
jclass cls = (*env)->FindClass(env, name);
if (cls != NULL) {
(*env)->ThrowNew(env, cls, msg);
}
}
/*
* Class: DirectIO
* Method: isFileInCache0
* Signature: (ILjava/lang/String;)Z
*/
JNIEXPORT jboolean Java_DirectIOTest_isFileInCache0(JNIEnv *env,
jclass cls,
jint file_size,
jstring file_path) {
void *f_mmap;
#ifdef __linux__
unsigned char *f_seg;
#else
char *f_seg;
#endif
#ifdef __APPLE__
size_t mask = MINCORE_INCORE;
#else
size_t mask = 0x1;
#endif
size_t page_size = getpagesize();
size_t index = (file_size + page_size - 1) /page_size;
jboolean result = JNI_FALSE;
const char* path = (*env)->GetStringUTFChars(env, file_path, JNI_FALSE);
int fd = open(path, O_RDWR);
(*env)->ReleaseStringUTFChars(env, file_path, path);
f_mmap = mmap(0, file_size, PROT_NONE, MAP_SHARED, fd, 0);
if (f_mmap == MAP_FAILED) {
close(fd);
ThrowException(env, "java/io/IOException",
"test of whether file exists in cache failed");
}
f_seg = malloc(index);
if (f_seg != NULL) {
if(mincore(f_mmap, file_size, f_seg) == 0) {
size_t i;
for (i = 0; i < index; i++) {
if (f_seg[i] & mask) {
result = JNI_TRUE;
break;
}
}
}
free(f_seg);
} else {
ThrowException(env, "java/io/IOException",
"test of whether file exists in cache failed");
}
close(fd);
munmap(f_mmap, file_size);
return result;
}
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