1 /*
2 * Copyright (c) 2001, 2018, 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_DevPollArrayWrapper.h"
31 #include <poll.h>
32 #include <unistd.h>
33 #include <sys/time.h>
34
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
38
39 typedef uint32_t caddr32_t;
40
41 /* /dev/poll ioctl */
42 #define DPIOC (0xD0 << 8)
43 #define DP_POLL (DPIOC | 1) /* poll on fds in cached in /dev/poll */
44 #define DP_ISPOLLED (DPIOC | 2) /* is this fd cached in /dev/poll */
45 #define DEVPOLLSIZE 1000 /* /dev/poll table size increment */
46 #define POLLREMOVE 0x0800 /* Removes fd from monitored set */
47
48 /*
49 * /dev/poll DP_POLL ioctl format
50 */
51 typedef struct dvpoll {
52 pollfd_t *dp_fds; /* pollfd array */
53 nfds_t dp_nfds; /* num of pollfd's in dp_fds[] */
54 int dp_timeout; /* time out in millisec */
55 } dvpoll_t;
56
57 typedef struct dvpoll32 {
58 caddr32_t dp_fds; /* pollfd array */
59 uint32_t dp_nfds; /* num of pollfd's in dp_fds[] */
60 int32_t dp_timeout; /* time out in millisec */
61 } dvpoll32_t;
62
63 #ifdef __cplusplus
64 }
65 #endif
66
67 #define RESTARTABLE(_cmd, _result) do { \
68 do { \
69 _result = _cmd; \
70 } while((_result == -1) && (errno == EINTR)); \
71 } while(0)
72
73 static int
74 idevpoll(jint wfd, int dpctl, struct dvpoll a)
75 {
76 jlong start, now;
77 int remaining = a.dp_timeout;
78 struct timeval t;
79 int diff;
80
81 gettimeofday(&t, NULL);
82 start = t.tv_sec * 1000 + t.tv_usec / 1000;
83
84 for (;;) {
85 /* poll(7d) ioctl does not return remaining count */
86 int res = ioctl(wfd, dpctl, &a);
87 if (res < 0 && errno == EINTR) {
88 if (remaining >= 0) {
89 gettimeofday(&t, NULL);
90 now = t.tv_sec * 1000 + t.tv_usec / 1000;
91 diff = now - start;
92 remaining -= diff;
93 if (diff < 0 || remaining <= 0) {
94 return 0;
95 }
96 start = now;
97 a.dp_timeout = remaining;
98 }
99 } else {
100 return res;
101 }
102 }
103 }
104
105 JNIEXPORT jint JNICALL
106 Java_sun_nio_ch_DevPollArrayWrapper_init(JNIEnv *env, jobject this)
107 {
108 int wfd = open("/dev/poll", O_RDWR);
109 if (wfd < 0) {
110 JNU_ThrowIOExceptionWithLastError(env, "Error opening driver");
111 return -1;
112 }
113 return wfd;
114 }
115
116 JNIEXPORT void JNICALL
117 Java_sun_nio_ch_DevPollArrayWrapper_register(JNIEnv *env, jobject this,
118 jint wfd, jint fd, jint mask)
119 {
120 struct pollfd a[1];
121 int n;
122
123 a[0].fd = fd;
124 a[0].events = mask;
125 a[0].revents = 0;
126
127 n = write(wfd, &a[0], sizeof(a));
128 if (n != sizeof(a)) {
129 if (n < 0) {
130 JNU_ThrowIOExceptionWithLastError(env, "Error writing pollfds");
131 } else {
132 JNU_ThrowIOException(env, "Unexpected number of bytes written");
133 }
134 }
135 }
136
137 JNIEXPORT void JNICALL
138 Java_sun_nio_ch_DevPollArrayWrapper_registerMultiple(JNIEnv *env, jobject this,
139 jint wfd, jlong address,
140 jint len)
141 {
142 unsigned char *pollBytes = (unsigned char *)jlong_to_ptr(address);
143 unsigned char *pollEnd = pollBytes + sizeof(struct pollfd) * len;
144 while (pollBytes < pollEnd) {
145 int bytesWritten = write(wfd, pollBytes, (int)(pollEnd - pollBytes));
146 if (bytesWritten < 0) {
147 JNU_ThrowIOExceptionWithLastError(env, "Error writing pollfds");
148 return;
149 }
150 pollBytes += bytesWritten;
151 }
152 }
153
154 JNIEXPORT jint JNICALL
155 Java_sun_nio_ch_DevPollArrayWrapper_poll0(JNIEnv *env, jobject this,
156 jlong address, jint numfds,
157 jlong timeout, jint wfd)
158 {
159 struct dvpoll a;
160 void *pfd = (void *) jlong_to_ptr(address);
161 int result = 0;
162
163 a.dp_fds = pfd;
164 a.dp_nfds = numfds;
165 a.dp_timeout = (int)timeout;
166
167 if (timeout <= 0) { /* Indefinite or no wait */
168 RESTARTABLE (ioctl(wfd, DP_POLL, &a), result);
169 } else { /* Bounded wait; bounded restarts */
170 result = idevpoll(wfd, DP_POLL, a);
171 }
172
173 if (result < 0) {
174 JNU_ThrowIOExceptionWithLastError(env, "Error reading driver");
175 return -1;
176 }
177 return result;
178 }