1 | /* |
1 | /* |
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2 | * libev epoll fd activity backend |
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3 | * |
2 | * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de> |
4 | * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de> |
3 | * All rights reserved. |
5 | * All rights reserved. |
4 | * |
6 | * |
5 | * Redistribution and use in source and binary forms, with or without |
7 | * Redistribution and use in source and binary forms, with or without modifica- |
6 | * modification, are permitted provided that the following conditions are |
8 | * tion, are permitted provided that the following conditions are met: |
7 | * met: |
9 | * |
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10 | * 1. Redistributions of source code must retain the above copyright notice, |
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11 | * this list of conditions and the following disclaimer. |
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12 | * |
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13 | * 2. Redistributions in binary form must reproduce the above copyright |
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14 | * notice, this list of conditions and the following disclaimer in the |
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15 | * documentation and/or other materials provided with the distribution. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
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18 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- |
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19 | * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
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20 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- |
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21 | * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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22 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
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23 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
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24 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- |
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25 | * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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26 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
8 | * |
27 | * |
9 | * * Redistributions of source code must retain the above copyright |
28 | * Alternatively, the contents of this file may be used under the terms of |
10 | * notice, this list of conditions and the following disclaimer. |
29 | * the GNU General Public License ("GPL") version 2 or any later version, |
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30 | * in which case the provisions of the GPL are applicable instead of |
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31 | * the above. If you wish to allow the use of your version of this file |
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32 | * only under the terms of the GPL and not to allow others to use your |
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33 | * version of this file under the BSD license, indicate your decision |
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34 | * by deleting the provisions above and replace them with the notice |
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35 | * and other provisions required by the GPL. If you do not delete the |
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36 | * provisions above, a recipient may use your version of this file under |
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37 | * either the BSD or the GPL. |
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38 | */ |
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39 | |
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40 | /* |
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41 | * general notes about epoll: |
11 | * |
42 | * |
12 | * * Redistributions in binary form must reproduce the above |
43 | * a) epoll silently removes fds from the fd set. as nothing tells us |
13 | * copyright notice, this list of conditions and the following |
44 | * that an fd has been removed otherwise, we have to continually |
14 | * disclaimer in the documentation and/or other materials provided |
45 | * "rearm" fds that we suspect *might* have changed (same |
15 | * with the distribution. |
46 | * problem with kqueue, but much less costly there). |
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47 | * b) the fact that ADD != MOD creates a lot of extra syscalls due to a) |
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48 | * and seems not to have any advantage. |
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49 | * c) the inability to handle fork or file descriptors (think dup) |
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50 | * limits the applicability over poll, so this is not a generic |
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51 | * poll replacement. |
16 | * |
52 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
53 | * lots of "weird code" and complication handling in this file is due |
18 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
54 | * to these design problems with epoll, as we try very hard to avoid |
19 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
55 | * epoll_ctl syscalls for common usage patterns. |
20 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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21 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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22 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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23 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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27 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | */ |
56 | */ |
29 | |
57 | |
30 | #include <sys/epoll.h> |
58 | #include <sys/epoll.h> |
31 | |
59 | |
32 | static int epoll_fd = -1; |
60 | static void |
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61 | epoll_modify (EV_P_ int fd, int oev, int nev) |
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62 | { |
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63 | struct epoll_event ev; |
33 | |
64 | |
34 | static void |
65 | /* |
35 | epoll_modify (int fd, int oev, int nev) |
66 | * we handle EPOLL_CTL_DEL by ignoring it here |
36 | { |
67 | * on the assumption that the fd is gone anyways |
37 | int mode = nev ? oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD : EPOLL_CTL_DEL; |
68 | * if that is wrong, we have to handle the spurious |
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69 | * event in epoll_poll. |
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70 | */ |
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71 | if (!nev) |
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72 | return; |
38 | |
73 | |
39 | struct epoll_event ev; |
74 | ev.data.u64 = fd; /* use u64 to fully initialise the struct, for nicer strace etc. */ |
40 | ev.data.fd = fd; |
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41 | ev.events = |
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42 | (nev & EV_READ ? EPOLLIN : 0) |
75 | ev.events = (nev & EV_READ ? EPOLLIN : 0) |
43 | | (nev & EV_WRITE ? EPOLLOUT : 0); |
76 | | (nev & EV_WRITE ? EPOLLOUT : 0); |
44 | |
77 | |
45 | epoll_ctl (epoll_fd, mode, fd, &ev); |
78 | if (expect_true (!epoll_ctl (backend_fd, oev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) |
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79 | return; |
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80 | |
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81 | if (expect_true (errno == ENOENT)) |
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82 | { |
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83 | /* on ENOENT the fd went away, so try to do the right thing */ |
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84 | if (!nev) |
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85 | return; |
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86 | |
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87 | if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev)) |
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88 | return; |
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89 | } |
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90 | else if (expect_true (errno == EEXIST)) |
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91 | { |
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92 | /* on EEXIST we ignored a previous DEL */ |
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93 | if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) |
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94 | return; |
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95 | } |
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96 | |
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97 | fd_kill (EV_A_ fd); |
46 | } |
98 | } |
47 | |
99 | |
48 | static void |
100 | static void |
49 | epoll_postfork_child (void) |
101 | epoll_poll (EV_P_ ev_tstamp timeout) |
50 | { |
102 | { |
51 | int fd; |
103 | int i; |
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104 | int eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, (int)ceil (timeout * 1000.)); |
52 | |
105 | |
53 | epoll_fd = epoll_create (256); |
106 | if (expect_false (eventcnt < 0)) |
54 | fcntl (epoll_fd, F_SETFD, FD_CLOEXEC); |
107 | { |
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108 | if (errno != EINTR) |
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109 | syserr ("(libev) epoll_wait"); |
55 | |
110 | |
56 | /* re-register interest in fds */ |
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57 | for (fd = 0; fd < anfdmax; ++fd) |
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58 | if (anfds [fd].events && !(anfds [fd].events & EV_REIFY))//D |
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59 | epoll_modify (fd, EV_NONE, anfds [fd].events); |
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60 | } |
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61 | |
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62 | static struct epoll_event *events; |
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63 | static int eventmax; |
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64 | |
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65 | static void |
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66 | epoll_poll (ev_tstamp timeout) |
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67 | { |
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68 | int eventcnt = epoll_wait (epoll_fd, events, eventmax, ceil (timeout * 1000.)); |
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69 | int i; |
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70 | |
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71 | if (eventcnt < 0) |
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72 | return; |
111 | return; |
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112 | } |
73 | |
113 | |
74 | for (i = 0; i < eventcnt; ++i) |
114 | for (i = 0; i < eventcnt; ++i) |
75 | fd_event ( |
115 | { |
76 | events [i].data.fd, |
116 | struct epoll_event *ev = epoll_events + i; |
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117 | |
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118 | int fd = ev->data.u64; |
77 | (events [i].events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) |
119 | int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) |
78 | | (events [i].events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0) |
120 | | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); |
79 | ); |
121 | int want = anfds [fd].events; |
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122 | |
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123 | if (expect_false (got & ~want)) |
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124 | { |
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125 | /* we received an event but are not interested in it, try mod or del */ |
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126 | ev->events = (want & EV_READ ? EPOLLIN : 0) |
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127 | | (want & EV_WRITE ? EPOLLOUT : 0); |
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128 | |
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129 | epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev); |
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130 | } |
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131 | |
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132 | fd_event (EV_A_ fd, got); |
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133 | } |
80 | |
134 | |
81 | /* if the receive array was full, increase its size */ |
135 | /* if the receive array was full, increase its size */ |
82 | if (eventcnt == eventmax) |
136 | if (expect_false (eventcnt == epoll_eventmax)) |
83 | { |
137 | { |
84 | free (events); |
138 | ev_free (epoll_events); |
85 | eventmax += eventmax >> 1; |
139 | epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1); |
86 | events = malloc (sizeof (struct epoll_event) * eventmax); |
140 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
87 | } |
141 | } |
88 | } |
142 | } |
89 | |
143 | |
90 | static void |
144 | int inline_size |
91 | epoll_init (int flags) |
145 | epoll_init (EV_P_ int flags) |
92 | { |
146 | { |
93 | epoll_fd = epoll_create (256); |
147 | backend_fd = epoll_create (256); |
94 | |
148 | |
95 | if (epoll_fd < 0) |
149 | if (backend_fd < 0) |
96 | return; |
150 | return 0; |
97 | |
151 | |
98 | fcntl (epoll_fd, F_SETFD, FD_CLOEXEC); |
152 | fcntl (backend_fd, F_SETFD, FD_CLOEXEC); |
99 | |
153 | |
100 | ev_method = EVMETHOD_EPOLL; |
154 | backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */ |
101 | method_fudge = 1e-3; /* needed to compensate for epoll returning early */ |
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102 | method_modify = epoll_modify; |
155 | backend_modify = epoll_modify; |
103 | method_poll = epoll_poll; |
156 | backend_poll = epoll_poll; |
104 | |
157 | |
105 | eventmax = 64; /* intiial number of events receivable per poll */ |
158 | epoll_eventmax = 64; /* intiial number of events receivable per poll */ |
106 | events = malloc (sizeof (struct epoll_event) * eventmax); |
159 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
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160 | |
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161 | return EVBACKEND_EPOLL; |
107 | } |
162 | } |
108 | |
163 | |
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164 | void inline_size |
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165 | epoll_destroy (EV_P) |
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166 | { |
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167 | ev_free (epoll_events); |
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168 | } |
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169 | |
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170 | void inline_size |
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171 | epoll_fork (EV_P) |
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172 | { |
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173 | close (backend_fd); |
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174 | |
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175 | while ((backend_fd = epoll_create (256)) < 0) |
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176 | syserr ("(libev) epoll_create"); |
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177 | |
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178 | fcntl (backend_fd, F_SETFD, FD_CLOEXEC); |
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179 | |
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180 | fd_rearm_all (EV_A); |
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181 | } |
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182 | |