1 /* java_nio_MappedByteBufferImpl.c - Native methods for MappedByteBufferImpl
2 Copyright (C) 2004,2005 Free Software Foundation, Inc.
3
4 This file is part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38 #include <config.h>
39 #include <errno.h>
40
41 #include <jni.h>
42 #include <jcl.h>
43
44 #include "java_nio_MappedByteBufferImpl.h"
45
46 #include <errno.h>
47 #include <string.h>
48 #include <stdlib.h>
49 #ifdef HAVE_UNISTD_H
50 #include <unistd.h>
51 #endif /* HAVE_UNISTD_H */
52 #ifdef HAVE_SYS_MMAN_H
53 #include <sys/mman.h>
54 #endif /* HAVE_SYS_MMAN_H */
55
56 #define IO_EXCEPTION "java/io/IOException"
57
58 /* FIXME these are defined in gnu_java_nio_channels_FileChannelImpl
59 too; should be someplace common. */
60 #define ALIGN_DOWN(p,s) ((jpointer)(p) - ((jpointer)(p) % (s)))
61 #define ALIGN_UP(p,s) ((jpointer)(p) + ((s) - ((jpointer)(p) % (s))))
62
63 /**
64 * Returns the memory page size of this platform.
65 *
66 * \return The page size.
67 */
68 static long
get_pagesize(void)69 get_pagesize (void)
70 {
71 /* FIXME can we just try HAVE_SYSCONF? */
72 #if defined(HAVE_GETPAGESIZE)
73 return getpagesize ();
74 #elif defined (HAVE_SYSCONF)
75 return sysconf (_SC_PAGESIZE);
76 #endif /* HAVE_GETPAGESIZE / HAVE_SYSCONF */
77 }
78
79 /**
80 * Retrieve the 'address' and 'cap' (the mapped size) fields of this
81 * buffer.
82 *
83 * This function will align the address down to the nearest page
84 * boundary, and the size up to the nearest page boundary. Thus, it is
85 * safe to use these values in 'mman' functions.
86 *
87 * \param env The JNI environment pointer.
88 * \param this The MappedByteBufferImpl instance.
89 * \param address A pointer to where the actual pointer should be
90 * stored.
91 * \param size A pointer to where the mapped region's size should be
92 * stored
93 */
94 static void
get_raw_values(JNIEnv * env,jobject this,void ** address,size_t * size)95 get_raw_values (JNIEnv *env, jobject this, void **address, size_t *size)
96 {
97 const long pagesize = get_pagesize ();
98 jfieldID MappedByteBufferImpl_address;
99 jfieldID MappedByteBufferImpl_size;
100 jobject MappedByteBufferImpl_address_value = NULL;
101
102 *address = NULL;
103 /* 'address' is declared in java.nio.Buffer */
104 MappedByteBufferImpl_address
105 = (*env)->GetFieldID (env, (*env)->GetObjectClass (env, this),
106 "address", "Lgnu/classpath/Pointer;");
107 /* 'cap' -- likewise, the capacity */
108 MappedByteBufferImpl_size
109 = (*env)->GetFieldID (env, (*env)->GetObjectClass (env, this),
110 "cap", "I");
111 if (MappedByteBufferImpl_address != NULL)
112 {
113 MappedByteBufferImpl_address_value =
114 (*env)->GetObjectField (env, this, MappedByteBufferImpl_address);
115 }
116 if ((*env)->ExceptionOccurred (env))
117 return;
118 if (MappedByteBufferImpl_address_value == NULL)
119 {
120 JCL_ThrowException (env, "java/lang/NullPointerException",
121 "mapped address is NULL");
122 return;
123 }
124
125 *address = (void *)
126 ALIGN_DOWN (JCL_GetRawData (env, MappedByteBufferImpl_address_value), pagesize);
127 *size = (size_t)
128 ALIGN_UP ((*env)->GetIntField (env, this, MappedByteBufferImpl_size),
129 pagesize);
130 }
131
132 JNIEXPORT void JNICALL
Java_java_nio_MappedByteBufferImpl_unmapImpl(JNIEnv * env,jobject this)133 Java_java_nio_MappedByteBufferImpl_unmapImpl (JNIEnv *env, jobject this)
134 {
135 #ifdef HAVE_MUNMAP
136 void *address;
137 size_t size;
138
139 get_raw_values (env, this, &address, &size);
140
141 if (address == NULL)
142 return;
143
144 if (munmap (address, size) != 0)
145 {
146 JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
147 return;
148 }
149 #else
150 JCL_ThrowException (env, IO_EXCEPTION,
151 "unmapping files not implemented");
152 #endif /* HAVE_MUNMAP */
153 }
154
155 JNIEXPORT jboolean JNICALL
Java_java_nio_MappedByteBufferImpl_isLoadedImpl(JNIEnv * env,jobject this)156 Java_java_nio_MappedByteBufferImpl_isLoadedImpl (JNIEnv * env, jobject this)
157 {
158 #ifdef HAVE_MINCORE
159 void *address;
160 size_t size;
161 char *vec;
162 size_t count, i;
163 const long pagesize = get_pagesize ();
164
165 /*
166 * FIXME on Darwin this does not work if the mapped region is
167 * exactly one page long; i.e., 'mincore' tells us it isn't loaded.
168 */
169 get_raw_values (env, this, &address, &size);
170 if (address == NULL)
171 return JNI_FALSE;
172 count = (size_t) ((size + pagesize - 1) / pagesize);
173 vec = (char *) malloc (count * sizeof (unsigned char));
174
175 /*
176 * Darwin (and BSD?) define argument 3 of 'mincore' to be 'char *',
177 * while GNU libc defines it to be 'unsigned char *'. Casting the
178 * argument to 'void *' fixes this, but not with C++. So you might
179 * be SOL if you compile this with g++ (!) on GNU with -Werror.
180 */
181 #ifdef __cplusplus
182 if (mincore (address, size, vec) != 0)
183 #else
184 if (mincore (address, size, (void *) vec) != 0)
185 #endif /* __cplusplus */
186 {
187 free (vec);
188 JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
189 return JNI_FALSE;
190 }
191
192 for (i = 0; i < count; i++)
193 {
194 if ((vec[i] & 1) == 0)
195 return JNI_FALSE;
196 }
197 return JNI_TRUE;
198 #else
199 return JNI_FALSE;
200 #endif
201 }
202
203 JNIEXPORT void JNICALL
Java_java_nio_MappedByteBufferImpl_loadImpl(JNIEnv * env,jobject this)204 Java_java_nio_MappedByteBufferImpl_loadImpl (JNIEnv *env, jobject this)
205 {
206 #ifdef HAVE_MADVISE
207 void *address;
208 size_t size;
209
210 get_raw_values (env, this, &address, &size);
211 if (address == NULL)
212 return;
213
214 madvise (address, size, MADV_WILLNEED);
215 #else
216 JCL_ThrowException (env, IO_EXCEPTION,
217 "forcing mapped files into core not implemented");
218 #endif /* HAVE_MADVISE */
219 }
220
221 JNIEXPORT void JNICALL
Java_java_nio_MappedByteBufferImpl_forceImpl(JNIEnv * env,jobject this)222 Java_java_nio_MappedByteBufferImpl_forceImpl (JNIEnv *env, jobject this)
223 {
224 #ifdef HAVE_MSYNC
225 void *address;
226 size_t size;
227
228 get_raw_values (env, this, &address, &size);
229
230 if (address == NULL)
231 return;
232
233 /* FIXME: is using MS_SYNC ok? Should we use MS_INVALIDATE? */
234 if (msync (address, size, MS_SYNC) != 0)
235 {
236 JCL_ThrowException (env, IO_EXCEPTION, strerror (errno));
237 }
238 #else
239 JCL_ThrowException (env, IO_EXCEPTION,
240 "forcing mapped files to disk not implemented");
241 #endif /* HAVE_MSYNC */
242 }
243