/*

 * Copyright (c) 2014, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

#include <unistd.h>

#include <errno.h>

#include "jni.h"

#include "jni_util.h"

#include "jlong.h"

#include "jdk_internal_jimage_concurrent_ConcurrentPReader.h"

#ifdef _ALLBSD_SOURCE

  #define pread64 pread

#endif

#define RESTARTABLE(_cmd, _result) do { \

  do { \

    _result = _cmd; \

  } while((_result == -1) && (errno == EINTR)); \

} while(0)

static jfieldID fd_fdID;

JNIEXPORT void JNICALL

Java_jdk_internal_jimage_concurrent_ConcurrentPReader_initIDs(JNIEnv *env, jclass clazz)

{

    CHECK_NULL(clazz = (*env)->FindClass(env, "java/io/FileDescriptor"));

    CHECK_NULL(fd_fdID = (*env)->GetFieldID(env, clazz, "fd", "I"));

}

JNIEXPORT jint JNICALL

Java_jdk_internal_jimage_concurrent_ConcurrentPReader_pread(JNIEnv *env, jclass clazz,

                                                            jobject fdo, jlong address,

                                                            jint len, jlong offset)

{

    jint fd = (*env)->GetIntField(env, fdo, fd_fdID);

    void *buf = (void *)jlong_to_ptr(address);

    int res;

    RESTARTABLE(pread64(fd, buf, len, offset), res);

    if (res == -1) {

        JNU_ThrowIOExceptionWithLastError(env, "pread failed");

    }

    return res;

}