1 /*
   2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 #include "jni.h"
  27 #include "jni_util.h"
  28 #include "jvm.h"
  29 #include "jlong.h"
  30 #include "java_nio_MappedByteBuffer.h"
  31 #include <assert.h>
  32 #include <sys/mman.h>
  33 #include <stddef.h>
  34 #include <stdlib.h>
  35 
  36 #ifdef _AIX
  37 #include <unistd.h>
  38 #endif
  39 
  40 
  41 #ifdef _AIX
  42 static long calculate_number_of_pages_in_range(void* address, size_t len, size_t pagesize) {
  43     uintptr_t address_unaligned = (uintptr_t) address;
  44     uintptr_t address_aligned = address_unaligned & (~(pagesize - 1));
  45     size_t len2 = len + (address_unaligned - address_aligned);
  46     long numPages = (len2 + pagesize - 1) / pagesize;
  47     return len2 + pagesize - 1 / pagesize;
  48 }
  49 #endif
  50 
  51 /* Output type for mincore(2) */
  52 #ifdef __linux__
  53 typedef unsigned char mincore_vec_t;
  54 #else
  55 typedef char mincore_vec_t;
  56 #endif
  57 
  58 JNIEXPORT jboolean JNICALL
  59 Java_java_nio_MappedByteBuffer_isLoaded0(JNIEnv *env, jobject obj, jlong address,
  60                                          jlong len, jint numPages)
  61 {
  62     jboolean loaded = JNI_TRUE;
  63     int result = 0;
  64     int i = 0;
  65     void *a = (void *) jlong_to_ptr(address);
  66     mincore_vec_t* vec = NULL;
  67 
  68 #ifdef _AIX
  69     /* See JDK-8186665 */
  70     size_t pagesize = (size_t)sysconf(_SC_PAGESIZE);
  71     if ((long)pagesize == -1) {
  72       return JNI_FALSE;
  73     }
  74     numPages = (jint) calculate_number_of_pages_in_range(a, len, pagesize);
  75 #endif
  76 
  77     vec = (mincore_vec_t*) malloc(numPages + 1);
  78 
  79     if (vec == NULL) {
  80         JNU_ThrowOutOfMemoryError(env, NULL);
  81         return JNI_FALSE;
  82     }
  83 
  84     vec[numPages] = '\x7f'; /* Sentinel */
  85     result = mincore(a, (size_t)len, vec);
  86     assert(vec[numPages] == '\x7f');
  87 
  88     if (result == -1) {
  89         JNU_ThrowIOExceptionWithLastError(env, "mincore failed");
  90         free(vec);
  91         return JNI_FALSE;
  92     }
  93 
  94     for (i=0; i<numPages; i++) {
  95         if (vec[i] == 0) {
  96             loaded = JNI_FALSE;
  97             break;
  98         }
  99     }
 100     free(vec);
 101     return loaded;
 102 }
 103 
 104 
 105 JNIEXPORT void JNICALL
 106 Java_java_nio_MappedByteBuffer_load0(JNIEnv *env, jobject obj, jlong address,
 107                                      jlong len)
 108 {
 109     char *a = (char *)jlong_to_ptr(address);
 110     int result = madvise((caddr_t)a, (size_t)len, MADV_WILLNEED);
 111     if (result == -1) {
 112         JNU_ThrowIOExceptionWithLastError(env, "madvise failed");
 113     }
 114 }
 115 
 116 
 117 JNIEXPORT void JNICALL
 118 Java_java_nio_MappedByteBuffer_force0(JNIEnv *env, jobject obj, jobject fdo,
 119                                       jlong address, jlong len)
 120 {
 121     void* a = (void *)jlong_to_ptr(address);
 122     int result = msync(a, (size_t)len, MS_SYNC);
 123     if (result == -1) {
 124         JNU_ThrowIOExceptionWithLastError(env, "msync failed");
 125     }
 126 }