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      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 
     42 static jfieldID fd_fdID;        /* for jint 'fd' in java.io.FileDescriptor */
     43 
     44 static 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 
     50 JNIEXPORT jboolean JNICALL
     51 IOUtil_randomBytes(JNIEnv *env, jclass clazz,
     52                                   jbyteArray randArray)
     53 {
     54     JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
     55     return JNI_FALSE;
     56 }
     57 
     58 JNIEXPORT jint JNICALL
     59 IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
     60 {
     61     return (*env)->GetIntField(env, fdo, fd_fdID);
     62 }
     63 
     64 JNIEXPORT void JNICALL
     65 IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
     66 {
     67     (*env)->SetIntField(env, fdo, fd_fdID, val);
     68 }
     69 
     70 static int
     71 configureBlocking(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 
     79 JNIEXPORT void JNICALL
     80 IOUtil_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 
     87 JNIEXPORT jlong JNICALL
     88 IOUtil_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 
    108 JNIEXPORT jboolean JNICALL
    109 IOUtil_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 
    125 JNIEXPORT jint JNICALL
    126 IOUtil_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 
    143 jint
    144 convertReturnVal(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 
    166 JNIEXPORT jint JNICALL
    167 IOUtil_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 
    178 jlong
    179 convertLongReturnVal(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 
    201 jint
    202 fdval(JNIEnv *env, jobject fdo)
    203 {
    204     return (*env)->GetIntField(env, fdo, fd_fdID);
    205 }
    206 
    207 static 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 
    218 void register_sun_nio_ch_IOUtil(JNIEnv* env) {
    219   jniRegisterNativeMethods(env, "sun/nio/ch/IOUtil", gMethods, NELEM(gMethods));
    220 
    221   IOUtil_initIDs(env);
    222 }
    223