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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 <nativehelper/JNIHelp.h>
     38 
     39 
     40 #define NATIVE_METHOD(className, functionName, signature) \
     41 { #functionName, signature, (void*)(className ## _ ## functionName) }
     42 
     43 static jfieldID fd_fdID;        /* for jint 'fd' in java.io.FileDescriptor */
     44 
     45 static void IOUtil_initIDs(JNIEnv *env)
     46 {
     47     jclass clazz = (*env)->FindClass(env, "java/io/FileDescriptor");
     48     CHECK_NULL(clazz);
     49     fd_fdID = (*env)->GetFieldID(env, clazz, "descriptor", "I");
     50     CHECK_NULL(fd_fdID);
     51 }
     52 
     53 JNIEXPORT jboolean JNICALL
     54 IOUtil_randomBytes(JNIEnv *env, jclass clazz,
     55                                   jbyteArray randArray)
     56 {
     57     JNU_ThrowByName(env, "java/lang/UnsupportedOperationException", NULL);
     58     return JNI_FALSE;
     59 }
     60 
     61 JNIEXPORT jint JNICALL
     62 IOUtil_fdVal(JNIEnv *env, jclass clazz, jobject fdo)
     63 {
     64     return (*env)->GetIntField(env, fdo, fd_fdID);
     65 }
     66 
     67 JNIEXPORT void JNICALL
     68 IOUtil_setfdVal(JNIEnv *env, jclass clazz, jobject fdo, jint val)
     69 {
     70     (*env)->SetIntField(env, fdo, fd_fdID, val);
     71 }
     72 
     73 static int
     74 configureBlocking(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 
     82 JNIEXPORT void JNICALL
     83 IOUtil_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 
     90 JNIEXPORT jlong JNICALL
     91 IOUtil_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 
    111 JNIEXPORT jboolean JNICALL
    112 IOUtil_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 
    128 JNIEXPORT jint JNICALL
    129 IOUtil_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 JNIEXPORT jint JNICALL
    145 IOUtil_iovMax(JNIEnv *env, jclass this)
    146 {
    147     jlong iov_max = sysconf(_SC_IOV_MAX);
    148     if (iov_max == -1)
    149         iov_max = 16;
    150     return (jint)iov_max;
    151 }
    152 
    153 /* Declared in nio_util.h for use elsewhere in NIO */
    154 
    155 jint
    156 convertReturnVal(JNIEnv *env, jint n, jboolean reading)
    157 {
    158     if (n > 0) /* Number of bytes written */
    159         return n;
    160     else if (n == 0) {
    161         if (reading) {
    162             return IOS_EOF; /* EOF is -1 in javaland */
    163         } else {
    164             return 0;
    165         }
    166     }
    167     else if (errno == EAGAIN)
    168         return IOS_UNAVAILABLE;
    169     else if (errno == EINTR)
    170         return IOS_INTERRUPTED;
    171     else {
    172         const char *msg = reading ? "Read failed" : "Write failed";
    173         JNU_ThrowIOExceptionWithLastError(env, msg);
    174         return IOS_THROWN;
    175     }
    176 }
    177 
    178 /* Declared in nio_util.h for use elsewhere in NIO */
    179 
    180 jlong
    181 convertLongReturnVal(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 
    203 jint
    204 fdval(JNIEnv *env, jobject fdo)
    205 {
    206     return (*env)->GetIntField(env, fdo, fd_fdID);
    207 }
    208 
    209 static 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 };
    219 
    220 void register_sun_nio_ch_IOUtil(JNIEnv* env) {
    221   jniRegisterNativeMethods(env, "sun/nio/ch/IOUtil", gMethods, NELEM(gMethods));
    222 
    223   IOUtil_initIDs(env);
    224 }
    225