IOUtil.c revision 74062e1c405d0943159bb52dcacd4df240e60621 
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
44
45JNIEXPORT void JNICALL
46IOUtil_initIDs(JNIEnv *env, jclass clazz)
47{
48    clazz = (*env)->FindClass(env, "java/io/FileDescriptor");
49    fd_fdID = (*env)->GetFieldID(env, clazz, "descriptor", "I");
50}
51
52JNIEXPORT jboolean JNICALL
53IOUtil_randomBytes(JNIEnv *env, jclass clazz,
54                                  jbyteArray randArray)
55{
56    JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
57    return JNI_FALSE;
58}
59
60JNIEXPORT jint JNICALL
61IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
62{
63    return (*env)->GetIntField(env, fdo, fd_fdID);
64}
65
66JNIEXPORT void JNICALL
67IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
68{
69    (*env)->SetIntField(env, fdo, fd_fdID, val);
70}
71
72static int
73configureBlocking(int fd, jboolean blocking)
74{
75    int flags = fcntl(fd, F_GETFL);
76    int newflags = blocking ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
77
78    return (flags == newflags) ? 0 : fcntl(fd, F_SETFL, newflags);
79}
80
81JNIEXPORT void JNICALL
82IOUtil_configureBlocking(JNIEnv *env, jclass clazz,
83                                         jobject fdo, jboolean blocking)
84{
85    if (configureBlocking(fdval(env, fdo), blocking) < 0)
86        JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
87}
88
89JNIEXPORT jlong JNICALL
90IOUtil_makePipe(JNIEnv *env, jobject this, jboolean blocking)
91{
92    int fd[2];
93
94    if (pipe(fd) < 0) {
95        JNU_ThrowIOExceptionWithLastError(env, "Pipe failed");
96        return 0;
97    }
98    if (blocking == JNI_FALSE) {
99        if ((configureBlocking(fd[0], JNI_FALSE) < 0)
100            || (configureBlocking(fd[1], JNI_FALSE) < 0)) {
101            JNU_ThrowIOExceptionWithLastError(env, "Configure blocking failed");
102            close(fd[0]);
103            close(fd[1]);
104            return 0;
105        }
106    }
107    return ((jlong) fd[0] << 32) | (jlong) fd[1];
108}
109
110JNIEXPORT jboolean JNICALL
111IOUtil_drain(JNIEnv *env, jclass cl, jint fd)
112{
113    char buf[128];
114    int tn = 0;
115
116    for (;;) {
117        int n = read(fd, buf, sizeof(buf));
118        tn += n;
119        if ((n < 0) && (errno != EAGAIN))
120            JNU_ThrowIOExceptionWithLastError(env, "Drain");
121        if (n == (int)sizeof(buf))
122            continue;
123        return (tn > 0) ? JNI_TRUE : JNI_FALSE;
124    }
125}
126
127JNIEXPORT jint JNICALL
128IOUtil_fdLimit(JNIEnv *env, jclass this)
129{
130    struct rlimit rlp;
131    if (getrlimit(RLIMIT_NOFILE, &rlp) < 0) {
132        JNU_ThrowIOExceptionWithLastError(env, "getrlimit failed");
133        return -1;
134    }
135    // Android-changed: Remove the rlimit < 0 check.
136    if (rlp.rlim_max > java_lang_Integer_MAX_VALUE) {
137        return java_lang_Integer_MAX_VALUE;
138    } else {
139        return (jint)rlp.rlim_max;
140    }
141}
142
143/* Declared in nio_util.h for use elsewhere in NIO */
144
145jint
146convertReturnVal(JNIEnv *env, jint n, jboolean reading)
147{
148    if (n > 0) /* Number of bytes written */
149        return n;
150    else if (n == 0) {
151        if (reading) {
152            return IOS_EOF; /* EOF is -1 in javaland */
153        } else {
154            return 0;
155        }
156    }
157    else if (errno == EAGAIN)
158        return IOS_UNAVAILABLE;
159    else if (errno == EINTR)
160        return IOS_INTERRUPTED;
161    else {
162        const char *msg = reading ? "Read failed" : "Write failed";
163        JNU_ThrowIOExceptionWithLastError(env, msg);
164        return IOS_THROWN;
165    }
166}
167
168JNIEXPORT jint JNICALL
169IOUtil_iovMax(JNIEnv *env, jclass this)
170{
171    jlong iov_max = sysconf(_SC_IOV_MAX);
172    if (iov_max == -1)
173        iov_max = 16;
174    return (jint)iov_max;
175}
176
177
178/* Declared in nio_util.h for use elsewhere in NIO */
179
180jlong
181convertLongReturnVal(JNIEnv *env, jlong n, jboolean reading)
182{
183    if (n > 0) /* Number of bytes written */
184        return n;
185    else if (n == 0) {
186        if (reading) {
187            return IOS_EOF; /* EOF is -1 in javaland */
188        } else {
189            return 0;
190        }
191    }
192    else if (errno == EAGAIN)
193        return IOS_UNAVAILABLE;
194    else if (errno == EINTR)
195        return IOS_INTERRUPTED;
196    else {
197        const char *msg = reading ? "Read failed" : "Write failed";
198        JNU_ThrowIOExceptionWithLastError(env, msg);
199        return IOS_THROWN;
200    }
201}
202
203jint
204fdval(JNIEnv *env, jobject fdo)
205{
206    return (*env)->GetIntField(env, fdo, fd_fdID);
207}
208
209static JNINativeMethod gMethods[] = {
210  NATIVE_METHOD(IOUtil, iovMax, "()I"),
211  NATIVE_METHOD(IOUtil, fdLimit, "()I"),
212  NATIVE_METHOD(IOUtil, drain, "(I)Z"),
213  NATIVE_METHOD(IOUtil, makePipe, "(Z)J"),
214  NATIVE_METHOD(IOUtil, configureBlocking, "(Ljava/io/FileDescriptor;Z)V"),
215  NATIVE_METHOD(IOUtil, setfdVal, "(Ljava/io/FileDescriptor;I)V"),
216  NATIVE_METHOD(IOUtil, fdVal, "(Ljava/io/FileDescriptor;)I"),
217  NATIVE_METHOD(IOUtil, randomBytes, "([B)Z"),
218  NATIVE_METHOD(IOUtil, initIDs, "()V"),
219};
220
221void register_sun_nio_ch_IOUtil(JNIEnv* env) {
222  jniRegisterNativeMethods(env, "sun/nio/ch/IOUtil", gMethods, NELEM(gMethods));
223}
224