IOUtil.c revision 3d43823e17818b3c5f45831f830884917b181454 
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 "sun_nio_ch_IOUtil.h"
35#include "java_lang_Integer.h"
36#include "nio.h"
37#include "nio_util.h"
38#include "JNIHelp.h"
39
40#define NATIVE_METHOD(className, functionName, signature) \
41{ #functionName, signature, (void*)(className ## _ ## functionName) }
42
43static jfieldID fd_fdID;        /* for jint 'fd' in java.io.FileDescriptor */
44
45
46JNIEXPORT void JNICALL
47IOUtil_initIDs(JNIEnv *env, jclass clazz)
48{
49    clazz = (*env)->FindClass(env, "java/io/FileDescriptor");
50    fd_fdID = (*env)->GetFieldID(env, clazz, "fd", "I");
51}
52
53JNIEXPORT jboolean JNICALL
54IOUtil_randomBytes(JNIEnv *env, jclass clazz,
55                                  jbyteArray randArray)
56{
57    JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
58    return JNI_FALSE;
59}
60
61JNIEXPORT jint JNICALL
62IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
63{
64    return (*env)->GetIntField(env, fdo, fd_fdID);
65}
66
67JNIEXPORT void JNICALL
68IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
69{
70    (*env)->SetIntField(env, fdo, fd_fdID, val);
71}
72
73static int
74configureBlocking(int fd, jboolean blocking)
75{
76    int flags = fcntl(fd, F_GETFL);
77    int newflags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
78
79    return (flags == newflags) ? 0 : fcntl(fd, F_SETFL, newflags);
80}
81
82JNIEXPORT void JNICALL
83IOUtil_configureBlocking(JNIEnv *env, jclass clazz,
84                                         jobject fdo, jboolean blocking)
85{
86    if (configureBlocking(fdval(env, fdo), blocking) < 0)
87        JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
88}
89
90JNIEXPORT jlong JNICALL
91IOUtil_makePipe(JNIEnv *env, jobject this, jboolean blocking)
92{
93    int fd[2];
94
95    if (pipe(fd) < 0) {
96        JNU_ThrowIOExceptionWithLastError(env, "Pipe failed");
97        return 0;
98    }
99    if (blocking == JNI_FALSE) {
100        if ((configureBlocking(fd[0], JNI_FALSE) < 0)
101            || (configureBlocking(fd[1], JNI_FALSE) < 0)) {
102            JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
103            close(fd[0]);
104            close(fd[1]);
105            return 0;
106        }
107    }
108    return ((jlong) fd[0] << 32) | (jlong) fd[1];
109}
110
111JNIEXPORT jboolean JNICALL
112IOUtil_drain(JNIEnv *env, jclass cl, jint fd)
113{
114    char buf[128];
115    int tn = 0;
116
117    for (;;) {
118        int n = read(fd, buf, sizeof(buf));
119        tn += n;
120        if ((n < 0) && (errno != EAGAIN))
121            JNU_ThrowIOExceptionWithLastError(env, "Drain");
122        if (n == (int)sizeof(buf))
123            continue;
124        return (tn > 0) ? JNI_TRUE : JNI_FALSE;
125    }
126}
127
128JNIEXPORT jint JNICALL
129IOUtil_fdLimit(JNIEnv *env, jclass this)
130{
131    struct rlimit rlp;
132    if (getrlimit(RLIMIT_NOFILE, &rlp) < 0) {
133        JNU_ThrowIOExceptionWithLastError(env, "getrlimit failed");
134        return -1;
135    }
136    // Android-changed: Remove the rlimit < 0 check.
137    if (rlp.rlim_max > java_lang_Integer_MAX_VALUE) {
138        return java_lang_Integer_MAX_VALUE;
139    } else {
140        return (jint)rlp.rlim_max;
141    }
142}
143
144/* Declared in nio_util.h for use elsewhere in NIO */
145
146jint
147convertReturnVal(JNIEnv *env, jint n, jboolean reading)
148{
149    if (n > 0) /* Number of bytes written */
150        return n;
151    else if (n == 0) {
152        if (reading) {
153            return IOS_EOF; /* EOF is -1 in javaland */
154        } else {
155            return 0;
156        }
157    }
158    else if (errno == EAGAIN)
159        return IOS_UNAVAILABLE;
160    else if (errno == EINTR)
161        return IOS_INTERRUPTED;
162    else {
163        const char *msg = reading ? "Read failed" : "Write failed";
164        JNU_ThrowIOExceptionWithLastError(env, msg);
165        return IOS_THROWN;
166    }
167}
168
169JNIEXPORT jint JNICALL
170IOUtil_iovMax(JNIEnv *env, jclass this)
171{
172    jlong iov_max = sysconf(_SC_IOV_MAX);
173    if (iov_max == -1)
174        iov_max = 16;
175    return (jint)iov_max;
176}
177
178
179/* Declared in nio_util.h for use elsewhere in NIO */
180
181jlong
182convertLongReturnVal(JNIEnv *env, jlong n, jboolean reading)
183{
184    if (n > 0) /* Number of bytes written */
185        return n;
186    else if (n == 0) {
187        if (reading) {
188            return IOS_EOF; /* EOF is -1 in javaland */
189        } else {
190            return 0;
191        }
192    }
193    else if (errno == EAGAIN)
194        return IOS_UNAVAILABLE;
195    else if (errno == EINTR)
196        return IOS_INTERRUPTED;
197    else {
198        const char *msg = reading ? "Read failed" : "Write failed";
199        JNU_ThrowIOExceptionWithLastError(env, msg);
200        return IOS_THROWN;
201    }
202}
203
204jint
205fdval(JNIEnv *env, jobject fdo)
206{
207    return (*env)->GetIntField(env, fdo, fd_fdID);
208}
209
210static JNINativeMethod gMethods[] = {
211  NATIVE_METHOD(IOUtil, iovMax, "()I"),
212  NATIVE_METHOD(IOUtil, fdLimit, "()I"),
213  NATIVE_METHOD(IOUtil, drain, "(I)Z"),
214  NATIVE_METHOD(IOUtil, makePipe, "(Z)J"),
215  NATIVE_METHOD(IOUtil, configureBlocking, "(Ljava/io/FileDescriptor;Z)V"),
216  NATIVE_METHOD(IOUtil, setfdVal, "(Ljava/io/FileDescriptor;I)V"),
217  NATIVE_METHOD(IOUtil, fdVal, "(Ljava/io/FileDescriptor;)I"),
218  NATIVE_METHOD(IOUtil, randomBytes, "([B)Z"),
219  NATIVE_METHOD(IOUtil, initIDs, "()V"),
220};
221
222void register_sun_nio_ch_IOUtil(JNIEnv* env) {
223  jniRegisterNativeMethods(env, "sun/nio/ch/IOUtil", gMethods, NELEM(gMethods));
224}
225