IOUtil.c revision f9d2599c4341d07938392d0d3f23a302755d4f93 
1/*
2 * Copyright (c) 2000, 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 <sys/types.h>
27#include <string.h>
28#include <sys/resource.h>
29
30#include "jni.h"
31#include "jni_util.h"
32#include "jvm.h"
33#include "jlong.h"
34#include "java_lang_Integer.h"
35#include "nio.h"
36#include "nio_util.h"
37#include "JNIHelp.h"
38
39#define NATIVE_METHOD(className, functionName, signature) \
40{ #functionName, signature, (void*)(className ## _ ## functionName) }
41
42static jfieldID fd_fdID;        /* for jint 'fd' in java.io.FileDescriptor */
43
44static void IOUtil_initIDs(JNIEnv *env)
45{
46    jclass clazz = (*env)->FindClass(env, "java/io/FileDescriptor");
47    fd_fdID = (*env)->GetFieldID(env, clazz, "descriptor", "I");
48}
49
50JNIEXPORT jboolean JNICALL
51IOUtil_randomBytes(JNIEnv *env, jclass clazz,
52                                  jbyteArray randArray)
53{
54    JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
55    return JNI_FALSE;
56}
57
58JNIEXPORT jint JNICALL
59IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
60{
61    return (*env)->GetIntField(env, fdo, fd_fdID);
62}
63
64JNIEXPORT void JNICALL
65IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
66{
67    (*env)->SetIntField(env, fdo, fd_fdID, val);
68}
69
70static int
71configureBlocking(int fd, jboolean blocking)
72{
73    int flags = fcntl(fd, F_GETFL);
74    int newflags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
75
76    return (flags == newflags) ? 0 : fcntl(fd, F_SETFL, newflags);
77}
78
79JNIEXPORT void JNICALL
80IOUtil_configureBlocking(JNIEnv *env, jclass clazz,
81                                         jobject fdo, jboolean blocking)
82{
83    if (configureBlocking(fdval(env, fdo), blocking) < 0)
84        JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
85}
86
87JNIEXPORT jlong JNICALL
88IOUtil_makePipe(JNIEnv *env, jobject this, jboolean blocking)
89{
90    int fd[2];
91
92    if (pipe(fd) < 0) {
93        JNU_ThrowIOExceptionWithLastError(env, "Pipe failed");
94        return 0;
95    }
96    if (blocking == JNI_FALSE) {
97        if ((configureBlocking(fd[0], JNI_FALSE) < 0)
98            || (configureBlocking(fd[1], JNI_FALSE) < 0)) {
99            JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
100            close(fd[0]);
101            close(fd[1]);
102            return 0;
103        }
104    }
105    return ((jlong) fd[0] << 32) | (jlong) fd[1];
106}
107
108JNIEXPORT jboolean JNICALL
109IOUtil_drain(JNIEnv *env, jclass cl, jint fd)
110{
111    char buf[128];
112    int tn = 0;
113
114    for (;;) {
115        int n = read(fd, buf, sizeof(buf));
116        tn += n;
117        if ((n < 0) && (errno != EAGAIN))
118            JNU_ThrowIOExceptionWithLastError(env, "Drain");
119        if (n == (int)sizeof(buf))
120            continue;
121        return (tn > 0) ? JNI_TRUE : JNI_FALSE;
122    }
123}
124
125JNIEXPORT jint JNICALL
126IOUtil_fdLimit(JNIEnv *env, jclass this)
127{
128    struct rlimit rlp;
129    if (getrlimit(RLIMIT_NOFILE, &rlp) < 0) {
130        JNU_ThrowIOExceptionWithLastError(env, "getrlimit failed");
131        return -1;
132    }
133    // Android-changed: Remove the rlimit < 0 check.
134    if (rlp.rlim_max > java_lang_Integer_MAX_VALUE) {
135        return java_lang_Integer_MAX_VALUE;
136    } else {
137        return (jint)rlp.rlim_max;
138    }
139}
140
141/* Declared in nio_util.h for use elsewhere in NIO */
142
143jint
144convertReturnVal(JNIEnv *env, jint n, jboolean reading)
145{
146    if (n > 0) /* Number of bytes written */
147        return n;
148    else if (n == 0) {
149        if (reading) {
150            return IOS_EOF; /* EOF is -1 in javaland */
151        } else {
152            return 0;
153        }
154    }
155    else if (errno == EAGAIN)
156        return IOS_UNAVAILABLE;
157    else if (errno == EINTR)
158        return IOS_INTERRUPTED;
159    else {
160        const char *msg = reading ? "Read failed" : "Write failed";
161        JNU_ThrowIOExceptionWithLastError(env, msg);
162        return IOS_THROWN;
163    }
164}
165
166JNIEXPORT jint JNICALL
167IOUtil_iovMax(JNIEnv *env, jclass this)
168{
169    jlong iov_max = sysconf(_SC_IOV_MAX);
170    if (iov_max == -1)
171        iov_max = 16;
172    return (jint)iov_max;
173}
174
175
176/* Declared in nio_util.h for use elsewhere in NIO */
177
178jlong
179convertLongReturnVal(JNIEnv *env, jlong n, jboolean reading)
180{
181    if (n > 0) /* Number of bytes written */
182        return n;
183    else if (n == 0) {
184        if (reading) {
185            return IOS_EOF; /* EOF is -1 in javaland */
186        } else {
187            return 0;
188        }
189    }
190    else if (errno == EAGAIN)
191        return IOS_UNAVAILABLE;
192    else if (errno == EINTR)
193        return IOS_INTERRUPTED;
194    else {
195        const char *msg = reading ? "Read failed" : "Write failed";
196        JNU_ThrowIOExceptionWithLastError(env, msg);
197        return IOS_THROWN;
198    }
199}
200
201jint
202fdval(JNIEnv *env, jobject fdo)
203{
204    return (*env)->GetIntField(env, fdo, fd_fdID);
205}
206
207static JNINativeMethod gMethods[] = {
208  NATIVE_METHOD(IOUtil, iovMax, "()I"),
209  NATIVE_METHOD(IOUtil, fdLimit, "()I"),
210  NATIVE_METHOD(IOUtil, drain, "(I)Z"),
211  NATIVE_METHOD(IOUtil, makePipe, "(Z)J"),
212  NATIVE_METHOD(IOUtil, configureBlocking, "(Ljava/io/FileDescriptor;Z)V"),
213  NATIVE_METHOD(IOUtil, setfdVal, "(Ljava/io/FileDescriptor;I)V"),
214  NATIVE_METHOD(IOUtil, fdVal, "(Ljava/io/FileDescriptor;)I"),
215  NATIVE_METHOD(IOUtil, randomBytes, "([B)Z"),
216};
217
218void register_sun_nio_ch_IOUtil(JNIEnv* env) {
219  jniRegisterNativeMethods(env, "sun/nio/ch/IOUtil", gMethods, NELEM(gMethods));
220
221  IOUtil_initIDs(env);
222}
223