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 "sun_nio_ch_PollArrayWrapper.h"
  31 #include <poll.h>
  32 #include <unistd.h>
  33 #include <sys/time.h>
  34 
  35 #define RESTARTABLE(_cmd, _result) do { \
  36   do { \
  37     _result = _cmd; \
  38   } while((_result == -1) && (errno == EINTR)); \
  39 } while(0)
  40 
  41 static int
  42 ipoll(struct pollfd fds[], unsigned int nfds, int timeout)
  43 {
  44     jlong start, now;
  45     int remaining = timeout;
  46     struct timeval t;
  47     int diff;
  48 
  49     gettimeofday(&t, NULL);
  50     start = t.tv_sec * 1000 + t.tv_usec / 1000;
  51 
  52     for (;;) {
  53         int res = poll(fds, nfds, remaining);
  54         if (res < 0 && errno == EINTR) {
  55             if (remaining >= 0) {
  56                 gettimeofday(&t, NULL);
  57                 now = t.tv_sec * 1000 + t.tv_usec / 1000;
  58                 diff = now - start;
  59                 remaining -= diff;
  60                 if (diff < 0 || remaining <= 0) {
  61                     return 0;
  62                 }
  63                 start = now;
  64             }
  65         } else {
  66             return res;
  67         }
  68     }
  69 }
  70 
  71 JNIEXPORT jint JNICALL
  72 Java_sun_nio_ch_PollArrayWrapper_poll0(JNIEnv *env, jobject this,
  73                                        jlong address, jint numfds,
  74                                        jlong timeout)
  75 {
  76     struct pollfd *a;
  77     int err = 0;
  78 
  79     a = (struct pollfd *) jlong_to_ptr(address);
  80 
  81     if (timeout <= 0) {           /* Indefinite or no wait */
  82         RESTARTABLE (poll(a, numfds, timeout), err);
  83     } else {                     /* Bounded wait; bounded restarts */
  84         err = ipoll(a, numfds, timeout);
  85     }
  86 
  87     if (err < 0) {
  88         JNU_ThrowIOExceptionWithLastError(env, "Poll failed");
  89     }
  90     return (jint)err;
  91 }
  92 
  93 JNIEXPORT void JNICALL
  94 Java_sun_nio_ch_PollArrayWrapper_interrupt(JNIEnv *env, jobject this, jint fd)
  95 {
  96     int fakebuf[1];
  97     fakebuf[0] = 1;
  98     if (write(fd, fakebuf, 1) < 0) {
  99          JNU_ThrowIOExceptionWithLastError(env,
 100                                           "Write to interrupt fd failed");
 101     }
 102 }