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1 /* |
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2 * Copyright (c) 2005, 2016, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 #include "jni.h" |
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27 #include "jni_util.h" |
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28 #include "jvm.h" |
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29 #include "jlong.h" |
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30 |
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31 #include "sun_nio_ch_EPollArrayWrapper.h" |
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32 |
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33 #include <unistd.h> |
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34 #include <sys/time.h> |
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35 #include <sys/epoll.h> |
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36 |
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37 #define RESTARTABLE(_cmd, _result) do { \ |
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38 do { \ |
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39 _result = _cmd; \ |
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40 } while((_result == -1) && (errno == EINTR)); \ |
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41 } while(0) |
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42 |
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43 |
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44 static int |
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45 iepoll(int epfd, struct epoll_event *events, int numfds, jlong timeout) |
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46 { |
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47 jlong start, now; |
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48 int remaining = timeout; |
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49 struct timeval t; |
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50 int diff; |
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51 |
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52 gettimeofday(&t, NULL); |
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53 start = t.tv_sec * 1000 + t.tv_usec / 1000; |
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54 |
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55 for (;;) { |
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56 int res = epoll_wait(epfd, events, numfds, remaining); |
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57 if (res < 0 && errno == EINTR) { |
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58 if (remaining >= 0) { |
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59 gettimeofday(&t, NULL); |
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60 now = t.tv_sec * 1000 + t.tv_usec / 1000; |
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61 diff = now - start; |
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62 remaining -= diff; |
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63 if (diff < 0 || remaining <= 0) { |
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64 return 0; |
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65 } |
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66 start = now; |
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67 } |
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68 } else { |
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69 return res; |
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70 } |
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71 } |
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72 } |
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73 |
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74 JNIEXPORT void JNICALL |
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75 Java_sun_nio_ch_EPollArrayWrapper_init(JNIEnv *env, jclass this) |
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76 { |
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77 } |
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78 |
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79 JNIEXPORT jint JNICALL |
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80 Java_sun_nio_ch_EPollArrayWrapper_epollCreate(JNIEnv *env, jobject this) |
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81 { |
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82 /* |
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83 * epoll_create expects a size as a hint to the kernel about how to |
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84 * dimension internal structures. We can't predict the size in advance. |
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85 */ |
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86 int epfd = epoll_create(256); |
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87 if (epfd < 0) { |
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88 JNU_ThrowIOExceptionWithLastError(env, "epoll_create failed"); |
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89 } |
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90 return epfd; |
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91 } |
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92 |
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93 JNIEXPORT jint JNICALL |
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94 Java_sun_nio_ch_EPollArrayWrapper_sizeofEPollEvent(JNIEnv* env, jclass this) |
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95 { |
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96 return sizeof(struct epoll_event); |
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97 } |
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98 |
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99 JNIEXPORT jint JNICALL |
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100 Java_sun_nio_ch_EPollArrayWrapper_offsetofData(JNIEnv* env, jclass this) |
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101 { |
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102 return offsetof(struct epoll_event, data); |
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103 } |
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104 |
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105 JNIEXPORT void JNICALL |
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106 Java_sun_nio_ch_EPollArrayWrapper_epollCtl(JNIEnv *env, jobject this, jint epfd, |
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107 jint opcode, jint fd, jint events) |
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108 { |
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109 struct epoll_event event; |
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110 int res; |
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111 |
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112 event.events = events; |
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113 event.data.fd = fd; |
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114 |
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115 RESTARTABLE(epoll_ctl(epfd, (int)opcode, (int)fd, &event), res); |
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116 |
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117 /* |
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118 * A channel may be registered with several Selectors. When each Selector |
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119 * is polled a EPOLL_CTL_DEL op will be inserted into its pending update |
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120 * list to remove the file descriptor from epoll. The "last" Selector will |
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121 * close the file descriptor which automatically unregisters it from each |
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122 * epoll descriptor. To avoid costly synchronization between Selectors we |
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123 * allow pending updates to be processed, ignoring errors. The errors are |
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124 * harmless as the last update for the file descriptor is guaranteed to |
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125 * be EPOLL_CTL_DEL. |
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126 */ |
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127 if (res < 0 && errno != EBADF && errno != ENOENT && errno != EPERM) { |
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128 JNU_ThrowIOExceptionWithLastError(env, "epoll_ctl failed"); |
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129 } |
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130 } |
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131 |
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132 JNIEXPORT jint JNICALL |
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133 Java_sun_nio_ch_EPollArrayWrapper_epollWait(JNIEnv *env, jobject this, |
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134 jlong address, jint numfds, |
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135 jlong timeout, jint epfd) |
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136 { |
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137 struct epoll_event *events = jlong_to_ptr(address); |
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138 int res; |
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139 |
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140 if (timeout <= 0) { /* Indefinite or no wait */ |
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141 RESTARTABLE(epoll_wait(epfd, events, numfds, timeout), res); |
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142 } else { /* Bounded wait; bounded restarts */ |
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143 res = iepoll(epfd, events, numfds, timeout); |
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144 } |
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145 |
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146 if (res < 0) { |
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147 JNU_ThrowIOExceptionWithLastError(env, "epoll_wait failed"); |
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148 } |
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149 return res; |
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150 } |
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151 |
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152 JNIEXPORT void JNICALL |
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153 Java_sun_nio_ch_EPollArrayWrapper_interrupt(JNIEnv *env, jobject this, jint fd) |
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154 { |
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155 int fakebuf[1]; |
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156 fakebuf[0] = 1; |
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157 if (write(fd, fakebuf, 1) < 0) { |
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158 JNU_ThrowIOExceptionWithLastError(env,"write to interrupt fd failed"); |
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159 } |
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160 } |