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      1 /*
      2  * Copyright (c) 2001, 2005, 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 "jni.h"
     27 #include "jni_util.h"
     28 #include "jvm.h"
     29 #include "jlong.h"
     30 #include <poll.h>
     31 #include <unistd.h>
     32 #include <sys/time.h>
     33 
     34 #define RESTARTABLE(_cmd, _result) do { \
     35   do { \
     36     _result = _cmd; \
     37   } while((_result == -1) && (errno == EINTR)); \
     38 } while(0)
     39 
     40 #include "JNIHelp.h"
     41 
     42 #define NATIVE_METHOD(className, functionName, signature) \
     43 { #functionName, signature, (void*)(Java_sun_nio_ch_ ## className ## _ ## functionName) }
     44 
     45 static int
     46 ipoll(struct pollfd fds[], unsigned int nfds, int timeout)
     47 {
     48     jlong start, now;
     49     int remaining = timeout;
     50     struct timeval t;
     51     int diff;
     52 
     53     gettimeofday(&t, NULL);
     54     start = t.tv_sec * 1000 + t.tv_usec / 1000;
     55 
     56     for (;;) {
     57         int res = poll(fds, nfds, remaining);
     58         if (res < 0 && errno == EINTR) {
     59             if (remaining >= 0) {
     60                 gettimeofday(&t, NULL);
     61                 now = t.tv_sec * 1000 + t.tv_usec / 1000;
     62                 diff = now - start;
     63                 remaining -= diff;
     64                 if (diff < 0 || remaining <= 0) {
     65                     return 0;
     66                 }
     67                 start = now;
     68             }
     69         } else {
     70             return res;
     71         }
     72     }
     73 }
     74 
     75 JNIEXPORT jint JNICALL
     76 Java_sun_nio_ch_PollArrayWrapper_poll0(JNIEnv *env, jobject this,
     77                                        jlong address, jint numfds,
     78                                        jlong timeout)
     79 {
     80     struct pollfd *a;
     81     int err = 0;
     82 
     83     a = (struct pollfd *) jlong_to_ptr(address);
     84 
     85     if (timeout <= 0) {           /* Indefinite or no wait */
     86         RESTARTABLE (poll(a, numfds, timeout), err);
     87     } else {                     /* Bounded wait; bounded restarts */
     88         err = ipoll(a, numfds, timeout);
     89     }
     90 
     91     if (err < 0) {
     92         JNU_ThrowIOExceptionWithLastError(env, "Poll failed");
     93     }
     94     return (jint)err;
     95 }
     96 
     97 JNIEXPORT void JNICALL
     98 Java_sun_nio_ch_PollArrayWrapper_interrupt(JNIEnv *env, jobject this, jint fd)
     99 {
    100     int fakebuf[1];
    101     fakebuf[0] = 1;
    102     if (write(fd, fakebuf, 1) < 0) {
    103          JNU_ThrowIOExceptionWithLastError(env,
    104                                           "Write to interrupt fd failed");
    105     }
    106 }
    107 
    108 
    109 static JNINativeMethod gMethods[] = {
    110   NATIVE_METHOD(PollArrayWrapper, poll0, "(JIJ)I"),
    111   NATIVE_METHOD(PollArrayWrapper, interrupt, "(I)V"),
    112 };
    113 
    114 void register_sun_nio_ch_PollArrayWrapper(JNIEnv* env) {
    115   jniRegisterNativeMethods(env, "sun/nio/ch/PollArrayWrapper", gMethods, NELEM(gMethods));
    116 }
    117