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
ipoll(struct pollfd fds[],unsigned int nfds,int timeout)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
Java_sun_nio_ch_PollArrayWrapper_poll0(JNIEnv * env,jobject this,jlong address,jint numfds,jlong timeout)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
Java_sun_nio_ch_PollArrayWrapper_interrupt(JNIEnv * env,jobject this,jint fd)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 }
103