1 | /* |
1 | /* |
2 | * libev epoll fd activity backend |
2 | * libev epoll fd activity backend |
3 | * |
3 | * |
4 | * Copyright (c) 2007,2008,2009,2010,2011 Marc Alexander Lehmann <libev@schmorp.de> |
4 | * Copyright (c) 2007,2008,2009,2010,2011,2016,2017,2019 Marc Alexander Lehmann <libev@schmorp.de> |
5 | * All rights reserved. |
5 | * All rights reserved. |
6 | * |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without modifica- |
7 | * Redistribution and use in source and binary forms, with or without modifica- |
8 | * tion, are permitted provided that the following conditions are met: |
8 | * tion, are permitted provided that the following conditions are met: |
9 | * |
9 | * |
… | |
… | |
91 | ev.data.u64 = (uint64_t)(uint32_t)fd |
91 | ev.data.u64 = (uint64_t)(uint32_t)fd |
92 | | ((uint64_t)(uint32_t)++anfds [fd].egen << 32); |
92 | | ((uint64_t)(uint32_t)++anfds [fd].egen << 32); |
93 | ev.events = (nev & EV_READ ? EPOLLIN : 0) |
93 | ev.events = (nev & EV_READ ? EPOLLIN : 0) |
94 | | (nev & EV_WRITE ? EPOLLOUT : 0); |
94 | | (nev & EV_WRITE ? EPOLLOUT : 0); |
95 | |
95 | |
96 | if (expect_true (!epoll_ctl (backend_fd, oev && oldmask != nev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) |
96 | if (ecb_expect_true (!epoll_ctl (backend_fd, oev && oldmask != nev ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd, &ev))) |
97 | return; |
97 | return; |
98 | |
98 | |
99 | if (expect_true (errno == ENOENT)) |
99 | if (ecb_expect_true (errno == ENOENT)) |
100 | { |
100 | { |
101 | /* if ENOENT then the fd went away, so try to do the right thing */ |
101 | /* if ENOENT then the fd went away, so try to do the right thing */ |
102 | if (!nev) |
102 | if (!nev) |
103 | goto dec_egen; |
103 | goto dec_egen; |
104 | |
104 | |
105 | if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev)) |
105 | if (!epoll_ctl (backend_fd, EPOLL_CTL_ADD, fd, &ev)) |
106 | return; |
106 | return; |
107 | } |
107 | } |
108 | else if (expect_true (errno == EEXIST)) |
108 | else if (ecb_expect_true (errno == EEXIST)) |
109 | { |
109 | { |
110 | /* EEXIST means we ignored a previous DEL, but the fd is still active */ |
110 | /* EEXIST means we ignored a previous DEL, but the fd is still active */ |
111 | /* if the kernel mask is the same as the new mask, we assume it hasn't changed */ |
111 | /* if the kernel mask is the same as the new mask, we assume it hasn't changed */ |
112 | if (oldmask == nev) |
112 | if (oldmask == nev) |
113 | goto dec_egen; |
113 | goto dec_egen; |
114 | |
114 | |
115 | if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) |
115 | if (!epoll_ctl (backend_fd, EPOLL_CTL_MOD, fd, &ev)) |
116 | return; |
116 | return; |
117 | } |
117 | } |
118 | else if (expect_true (errno == EPERM)) |
118 | else if (ecb_expect_true (errno == EPERM)) |
119 | { |
119 | { |
120 | /* EPERM means the fd is always ready, but epoll is too snobbish */ |
120 | /* EPERM means the fd is always ready, but epoll is too snobbish */ |
121 | /* to handle it, unlike select or poll. */ |
121 | /* to handle it, unlike select or poll. */ |
122 | anfds [fd].emask = EV_EMASK_EPERM; |
122 | anfds [fd].emask = EV_EMASK_EPERM; |
123 | |
123 | |
124 | /* add fd to epoll_eperms, if not already inside */ |
124 | /* add fd to epoll_eperms, if not already inside */ |
125 | if (!(oldmask & EV_EMASK_EPERM)) |
125 | if (!(oldmask & EV_EMASK_EPERM)) |
126 | { |
126 | { |
127 | array_needsize (int, epoll_eperms, epoll_epermmax, epoll_epermcnt + 1, EMPTY2); |
127 | array_needsize (int, epoll_eperms, epoll_epermmax, epoll_epermcnt + 1, array_needsize_noinit); |
128 | epoll_eperms [epoll_epermcnt++] = fd; |
128 | epoll_eperms [epoll_epermcnt++] = fd; |
129 | } |
129 | } |
130 | |
130 | |
131 | return; |
131 | return; |
132 | } |
132 | } |
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133 | else |
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134 | assert (("libev: I/O watcher with invalid fd found in epoll_ctl", errno != EBADF && errno != ELOOP && errno != EINVAL)); |
133 | |
135 | |
134 | fd_kill (EV_A_ fd); |
136 | fd_kill (EV_A_ fd); |
135 | |
137 | |
136 | dec_egen: |
138 | dec_egen: |
137 | /* we didn't successfully call epoll_ctl, so decrement the generation counter again */ |
139 | /* we didn't successfully call epoll_ctl, so decrement the generation counter again */ |
… | |
… | |
142 | epoll_poll (EV_P_ ev_tstamp timeout) |
144 | epoll_poll (EV_P_ ev_tstamp timeout) |
143 | { |
145 | { |
144 | int i; |
146 | int i; |
145 | int eventcnt; |
147 | int eventcnt; |
146 | |
148 | |
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149 | if (ecb_expect_false (epoll_epermcnt)) |
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150 | timeout = 0.; |
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|
151 | |
147 | /* epoll wait times cannot be larger than (LONG_MAX - 999UL) / HZ msecs, which is below */ |
152 | /* epoll wait times cannot be larger than (LONG_MAX - 999UL) / HZ msecs, which is below */ |
148 | /* the default libev max wait time, however. */ |
153 | /* the default libev max wait time, however. */ |
149 | EV_RELEASE_CB; |
154 | EV_RELEASE_CB; |
150 | eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, |
155 | eventcnt = epoll_wait (backend_fd, epoll_events, epoll_eventmax, EV_TS_TO_MS (timeout)); |
151 | epoll_epermcnt ? 0 : ev_timeout_to_ms (timeout)); |
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152 | EV_ACQUIRE_CB; |
156 | EV_ACQUIRE_CB; |
153 | |
157 | |
154 | if (expect_false (eventcnt < 0)) |
158 | if (ecb_expect_false (eventcnt < 0)) |
155 | { |
159 | { |
156 | if (errno != EINTR) |
160 | if (errno != EINTR) |
157 | ev_syserr ("(libev) epoll_wait"); |
161 | ev_syserr ("(libev) epoll_wait"); |
158 | |
162 | |
159 | return; |
163 | return; |
… | |
… | |
166 | int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */ |
170 | int fd = (uint32_t)ev->data.u64; /* mask out the lower 32 bits */ |
167 | int want = anfds [fd].events; |
171 | int want = anfds [fd].events; |
168 | int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) |
172 | int got = (ev->events & (EPOLLOUT | EPOLLERR | EPOLLHUP) ? EV_WRITE : 0) |
169 | | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); |
173 | | (ev->events & (EPOLLIN | EPOLLERR | EPOLLHUP) ? EV_READ : 0); |
170 | |
174 | |
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175 | /* |
171 | /* check for spurious notification */ |
176 | * check for spurious notification. |
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177 | * this only finds spurious notifications on egen updates |
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178 | * other spurious notifications will be found by epoll_ctl, below |
172 | /* we assume that fd is always in range, as we never shrink the anfds array */ |
179 | * we assume that fd is always in range, as we never shrink the anfds array |
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180 | */ |
173 | if (expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32))) |
181 | if (ecb_expect_false ((uint32_t)anfds [fd].egen != (uint32_t)(ev->data.u64 >> 32))) |
174 | { |
182 | { |
175 | /* recreate kernel state */ |
183 | /* recreate kernel state */ |
176 | postfork = 1; |
184 | postfork |= 2; |
177 | continue; |
185 | continue; |
178 | } |
186 | } |
179 | |
187 | |
180 | if (expect_false (got & ~want)) |
188 | if (ecb_expect_false (got & ~want)) |
181 | { |
189 | { |
182 | anfds [fd].emask = want; |
190 | anfds [fd].emask = want; |
183 | |
191 | |
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|
192 | /* |
184 | /* we received an event but are not interested in it, try mod or del */ |
193 | * we received an event but are not interested in it, try mod or del |
185 | /* I don't think we ever need MOD, but let's handle it anyways */ |
194 | * this often happens because we optimistically do not unregister fds |
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195 | * when we are no longer interested in them, but also when we get spurious |
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196 | * notifications for fds from another process. this is partially handled |
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197 | * above with the gencounter check (== our fd is not the event fd), and |
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198 | * partially here, when epoll_ctl returns an error (== a child has the fd |
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199 | * but we closed it). |
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200 | * note: for events such as POLLHUP, where we can't know whether it refers |
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201 | * to EV_READ or EV_WRITE, we might issue redundant EPOLL_CTL_MOD calls. |
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202 | */ |
186 | ev->events = (want & EV_READ ? EPOLLIN : 0) |
203 | ev->events = (want & EV_READ ? EPOLLIN : 0) |
187 | | (want & EV_WRITE ? EPOLLOUT : 0); |
204 | | (want & EV_WRITE ? EPOLLOUT : 0); |
188 | |
205 | |
189 | /* pre-2.6.9 kernels require a non-null pointer with EPOLL_CTL_DEL, */ |
206 | /* pre-2.6.9 kernels require a non-null pointer with EPOLL_CTL_DEL, */ |
190 | /* which is fortunately easy to do for us. */ |
207 | /* which is fortunately easy to do for us. */ |
191 | if (epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev)) |
208 | if (epoll_ctl (backend_fd, want ? EPOLL_CTL_MOD : EPOLL_CTL_DEL, fd, ev)) |
192 | { |
209 | { |
193 | postfork = 1; /* an error occurred, recreate kernel state */ |
210 | postfork |= 2; /* an error occurred, recreate kernel state */ |
194 | continue; |
211 | continue; |
195 | } |
212 | } |
196 | } |
213 | } |
197 | |
214 | |
198 | fd_event (EV_A_ fd, got); |
215 | fd_event (EV_A_ fd, got); |
199 | } |
216 | } |
200 | |
217 | |
201 | /* if the receive array was full, increase its size */ |
218 | /* if the receive array was full, increase its size */ |
202 | if (expect_false (eventcnt == epoll_eventmax)) |
219 | if (ecb_expect_false (eventcnt == epoll_eventmax)) |
203 | { |
220 | { |
204 | ev_free (epoll_events); |
221 | ev_free (epoll_events); |
205 | epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1); |
222 | epoll_eventmax = array_nextsize (sizeof (struct epoll_event), epoll_eventmax, epoll_eventmax + 1); |
206 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
223 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
207 | } |
224 | } |
… | |
… | |
213 | unsigned char events = anfds [fd].events & (EV_READ | EV_WRITE); |
230 | unsigned char events = anfds [fd].events & (EV_READ | EV_WRITE); |
214 | |
231 | |
215 | if (anfds [fd].emask & EV_EMASK_EPERM && events) |
232 | if (anfds [fd].emask & EV_EMASK_EPERM && events) |
216 | fd_event (EV_A_ fd, events); |
233 | fd_event (EV_A_ fd, events); |
217 | else |
234 | else |
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235 | { |
218 | epoll_eperms [i] = epoll_eperms [--epoll_epermcnt]; |
236 | epoll_eperms [i] = epoll_eperms [--epoll_epermcnt]; |
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237 | anfds [fd].emask = 0; |
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238 | } |
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239 | } |
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240 | } |
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241 | |
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242 | static int |
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243 | epoll_epoll_create (void) |
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244 | { |
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245 | int fd; |
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246 | |
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247 | #if defined EPOLL_CLOEXEC && !defined __ANDROID__ |
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248 | fd = epoll_create1 (EPOLL_CLOEXEC); |
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249 | |
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250 | if (fd < 0 && (errno == EINVAL || errno == ENOSYS)) |
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251 | #endif |
219 | } |
252 | { |
220 | } |
253 | fd = epoll_create (256); |
221 | |
254 | |
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255 | if (fd >= 0) |
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256 | fcntl (fd, F_SETFD, FD_CLOEXEC); |
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257 | } |
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258 | |
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259 | return fd; |
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260 | } |
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261 | |
222 | int inline_size |
262 | inline_size |
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263 | int |
223 | epoll_init (EV_P_ int flags) |
264 | epoll_init (EV_P_ int flags) |
224 | { |
265 | { |
225 | #ifdef EPOLL_CLOEXEC |
266 | if ((backend_fd = epoll_epoll_create ()) < 0) |
226 | backend_fd = epoll_create1 (EPOLL_CLOEXEC); |
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227 | |
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228 | if (backend_fd <= 0) |
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229 | #endif |
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230 | backend_fd = epoll_create (256); |
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231 | |
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232 | if (backend_fd < 0) |
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233 | return 0; |
267 | return 0; |
234 | |
268 | |
235 | fcntl (backend_fd, F_SETFD, FD_CLOEXEC); |
269 | backend_mintime = 1e-3; /* epoll does sometimes return early, this is just to avoid the worst */ |
236 | |
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237 | backend_fudge = 0.; /* kernel sources seem to indicate this to be zero */ |
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238 | backend_modify = epoll_modify; |
270 | backend_modify = epoll_modify; |
239 | backend_poll = epoll_poll; |
271 | backend_poll = epoll_poll; |
240 | |
272 | |
241 | epoll_eventmax = 64; /* initial number of events receivable per poll */ |
273 | epoll_eventmax = 64; /* initial number of events receivable per poll */ |
242 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
274 | epoll_events = (struct epoll_event *)ev_malloc (sizeof (struct epoll_event) * epoll_eventmax); |
243 | |
275 | |
244 | return EVBACKEND_EPOLL; |
276 | return EVBACKEND_EPOLL; |
245 | } |
277 | } |
246 | |
278 | |
247 | void inline_size |
279 | inline_size |
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280 | void |
248 | epoll_destroy (EV_P) |
281 | epoll_destroy (EV_P) |
249 | { |
282 | { |
250 | ev_free (epoll_events); |
283 | ev_free (epoll_events); |
251 | array_free (epoll_eperm, EMPTY); |
284 | array_free (epoll_eperm, EMPTY); |
252 | } |
285 | } |
253 | |
286 | |
254 | void inline_size |
287 | ecb_cold |
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288 | static void |
255 | epoll_fork (EV_P) |
289 | epoll_fork (EV_P) |
256 | { |
290 | { |
257 | close (backend_fd); |
291 | close (backend_fd); |
258 | |
292 | |
259 | while ((backend_fd = epoll_create (256)) < 0) |
293 | while ((backend_fd = epoll_epoll_create ()) < 0) |
260 | ev_syserr ("(libev) epoll_create"); |
294 | ev_syserr ("(libev) epoll_create"); |
261 | |
295 | |
262 | fcntl (backend_fd, F_SETFD, FD_CLOEXEC); |
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263 | |
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264 | fd_rearm_all (EV_A); |
296 | fd_rearm_all (EV_A); |
265 | } |
297 | } |
266 | |
298 | |