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 }