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[Samba/gebeck_regimport.git] / lib / tevent / tevent_epoll.c
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1 /*
2 Unix SMB/CIFS implementation.
4 main select loop and event handling - epoll implementation
6 Copyright (C) Andrew Tridgell 2003-2005
7 Copyright (C) Stefan Metzmacher 2005-2009
9 ** NOTE! The following LGPL license applies to the tevent
10 ** library. This does NOT imply that all of Samba is released
11 ** under the LGPL
13 This library is free software; you can redistribute it and/or
14 modify it under the terms of the GNU Lesser General Public
15 License as published by the Free Software Foundation; either
16 version 3 of the License, or (at your option) any later version.
18 This library is distributed in the hope that it will be useful,
19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
21 Lesser General Public License for more details.
23 You should have received a copy of the GNU Lesser General Public
24 License along with this library; if not, see <http://www.gnu.org/licenses/>.
27 #include "replace.h"
28 #include "system/filesys.h"
29 #include "system/select.h"
30 #include "tevent.h"
31 #include "tevent_internal.h"
32 #include "tevent_util.h"
34 struct epoll_event_context {
35 /* a pointer back to the generic event_context */
36 struct tevent_context *ev;
38 /* when using epoll this is the handle from epoll_create */
39 int epoll_fd;
41 pid_t pid;
45 called when a epoll call fails
47 static void epoll_panic(struct epoll_event_context *epoll_ev, const char *reason)
49 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL,
50 "%s (%s) - calling abort()\n", reason, strerror(errno));
51 abort();
55 map from TEVENT_FD_* to EPOLLIN/EPOLLOUT
57 static uint32_t epoll_map_flags(uint16_t flags)
59 uint32_t ret = 0;
60 if (flags & TEVENT_FD_READ) ret |= (EPOLLIN | EPOLLERR | EPOLLHUP);
61 if (flags & TEVENT_FD_WRITE) ret |= (EPOLLOUT | EPOLLERR | EPOLLHUP);
62 return ret;
66 free the epoll fd
68 static int epoll_ctx_destructor(struct epoll_event_context *epoll_ev)
70 close(epoll_ev->epoll_fd);
71 epoll_ev->epoll_fd = -1;
72 return 0;
76 init the epoll fd
78 static int epoll_init_ctx(struct epoll_event_context *epoll_ev)
80 epoll_ev->epoll_fd = epoll_create(64);
81 if (epoll_ev->epoll_fd == -1) {
82 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL,
83 "Failed to create epoll handle.\n");
84 return -1;
87 if (!ev_set_close_on_exec(epoll_ev->epoll_fd)) {
88 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_WARNING,
89 "Failed to set close-on-exec, file descriptor may be leaked to children.\n");
92 epoll_ev->pid = getpid();
93 talloc_set_destructor(epoll_ev, epoll_ctx_destructor);
95 return 0;
98 static void epoll_add_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde);
101 reopen the epoll handle when our pid changes
102 see http://junkcode.samba.org/ftp/unpacked/junkcode/epoll_fork.c for an
103 demonstration of why this is needed
105 static void epoll_check_reopen(struct epoll_event_context *epoll_ev)
107 struct tevent_fd *fde;
109 if (epoll_ev->pid == getpid()) {
110 return;
113 close(epoll_ev->epoll_fd);
114 epoll_ev->epoll_fd = epoll_create(64);
115 if (epoll_ev->epoll_fd == -1) {
116 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL,
117 "Failed to recreate epoll handle after fork\n");
118 return;
121 if (!ev_set_close_on_exec(epoll_ev->epoll_fd)) {
122 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_WARNING,
123 "Failed to set close-on-exec, file descriptor may be leaked to children.\n");
126 epoll_ev->pid = getpid();
127 for (fde=epoll_ev->ev->fd_events;fde;fde=fde->next) {
128 epoll_add_event(epoll_ev, fde);
132 #define EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT (1<<0)
133 #define EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR (1<<1)
134 #define EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR (1<<2)
137 add the epoll event to the given fd_event
139 static void epoll_add_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde)
141 struct epoll_event event;
143 if (epoll_ev->epoll_fd == -1) return;
145 fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
147 /* if we don't want events yet, don't add an epoll_event */
148 if (fde->flags == 0) return;
150 ZERO_STRUCT(event);
151 event.events = epoll_map_flags(fde->flags);
152 event.data.ptr = fde;
153 if (epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_ADD, fde->fd, &event) != 0) {
154 epoll_panic(epoll_ev, "EPOLL_CTL_ADD failed");
156 fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT;
158 /* only if we want to read we want to tell the event handler about errors */
159 if (fde->flags & TEVENT_FD_READ) {
160 fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
165 delete the epoll event for given fd_event
167 static void epoll_del_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde)
169 struct epoll_event event;
171 if (epoll_ev->epoll_fd == -1) return;
173 fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
175 /* if there's no epoll_event, we don't need to delete it */
176 if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT)) return;
178 ZERO_STRUCT(event);
179 event.events = epoll_map_flags(fde->flags);
180 event.data.ptr = fde;
181 if (epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_DEL, fde->fd, &event) != 0) {
182 tevent_debug(epoll_ev->ev, TEVENT_DEBUG_FATAL,
183 "epoll_del_event failed! probable early close bug (%s)\n",
184 strerror(errno));
186 fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT;
190 change the epoll event to the given fd_event
192 static void epoll_mod_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde)
194 struct epoll_event event;
195 if (epoll_ev->epoll_fd == -1) return;
197 fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
199 ZERO_STRUCT(event);
200 event.events = epoll_map_flags(fde->flags);
201 event.data.ptr = fde;
202 if (epoll_ctl(epoll_ev->epoll_fd, EPOLL_CTL_MOD, fde->fd, &event) != 0) {
203 epoll_panic(epoll_ev, "EPOLL_CTL_MOD failed");
206 /* only if we want to read we want to tell the event handler about errors */
207 if (fde->flags & TEVENT_FD_READ) {
208 fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
212 static void epoll_change_event(struct epoll_event_context *epoll_ev, struct tevent_fd *fde)
214 bool got_error = (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR);
215 bool want_read = (fde->flags & TEVENT_FD_READ);
216 bool want_write= (fde->flags & TEVENT_FD_WRITE);
218 if (epoll_ev->epoll_fd == -1) return;
220 fde->additional_flags &= ~EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR;
222 /* there's already an event */
223 if (fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_HAS_EVENT) {
224 if (want_read || (want_write && !got_error)) {
225 epoll_mod_event(epoll_ev, fde);
226 return;
229 * if we want to match the select behavior, we need to remove the epoll_event
230 * when the caller isn't interested in events.
232 * this is because epoll reports EPOLLERR and EPOLLHUP, even without asking for them
234 epoll_del_event(epoll_ev, fde);
235 return;
238 /* there's no epoll_event attached to the fde */
239 if (want_read || (want_write && !got_error)) {
240 epoll_add_event(epoll_ev, fde);
241 return;
246 event loop handling using epoll
248 static int epoll_event_loop(struct epoll_event_context *epoll_ev, struct timeval *tvalp)
250 int ret, i;
251 #define MAXEVENTS 1
252 struct epoll_event events[MAXEVENTS];
253 int timeout = -1;
255 if (epoll_ev->epoll_fd == -1) return -1;
257 if (tvalp) {
258 /* it's better to trigger timed events a bit later than to early */
259 timeout = ((tvalp->tv_usec+999) / 1000) + (tvalp->tv_sec*1000);
262 if (epoll_ev->ev->signal_events &&
263 tevent_common_check_signal(epoll_ev->ev)) {
264 return 0;
267 tevent_trace_point_callback(epoll_ev->ev, TEVENT_TRACE_BEFORE_WAIT);
268 ret = epoll_wait(epoll_ev->epoll_fd, events, MAXEVENTS, timeout);
269 tevent_trace_point_callback(epoll_ev->ev, TEVENT_TRACE_AFTER_WAIT);
271 if (ret == -1 && errno == EINTR && epoll_ev->ev->signal_events) {
272 if (tevent_common_check_signal(epoll_ev->ev)) {
273 return 0;
277 if (ret == -1 && errno != EINTR) {
278 epoll_panic(epoll_ev, "epoll_wait() failed");
279 return -1;
282 if (ret == 0 && tvalp) {
283 /* we don't care about a possible delay here */
284 tevent_common_loop_timer_delay(epoll_ev->ev);
285 return 0;
288 for (i=0;i<ret;i++) {
289 struct tevent_fd *fde = talloc_get_type(events[i].data.ptr,
290 struct tevent_fd);
291 uint16_t flags = 0;
293 if (fde == NULL) {
294 epoll_panic(epoll_ev, "epoll_wait() gave bad data");
295 return -1;
297 if (events[i].events & (EPOLLHUP|EPOLLERR)) {
298 fde->additional_flags |= EPOLL_ADDITIONAL_FD_FLAG_GOT_ERROR;
300 * if we only wait for TEVENT_FD_WRITE, we should not tell the
301 * event handler about it, and remove the epoll_event,
302 * as we only report errors when waiting for read events,
303 * to match the select() behavior
305 if (!(fde->additional_flags & EPOLL_ADDITIONAL_FD_FLAG_REPORT_ERROR)) {
306 epoll_del_event(epoll_ev, fde);
307 continue;
309 flags |= TEVENT_FD_READ;
311 if (events[i].events & EPOLLIN) flags |= TEVENT_FD_READ;
312 if (events[i].events & EPOLLOUT) flags |= TEVENT_FD_WRITE;
313 if (flags) {
314 fde->handler(epoll_ev->ev, fde, flags, fde->private_data);
315 break;
319 return 0;
323 create a epoll_event_context structure.
325 static int epoll_event_context_init(struct tevent_context *ev)
327 int ret;
328 struct epoll_event_context *epoll_ev;
330 epoll_ev = talloc_zero(ev, struct epoll_event_context);
331 if (!epoll_ev) return -1;
332 epoll_ev->ev = ev;
333 epoll_ev->epoll_fd = -1;
335 ret = epoll_init_ctx(epoll_ev);
336 if (ret != 0) {
337 talloc_free(epoll_ev);
338 return ret;
341 ev->additional_data = epoll_ev;
342 return 0;
346 destroy an fd_event
348 static int epoll_event_fd_destructor(struct tevent_fd *fde)
350 struct tevent_context *ev = fde->event_ctx;
351 struct epoll_event_context *epoll_ev = NULL;
353 if (ev) {
354 epoll_ev = talloc_get_type(ev->additional_data,
355 struct epoll_event_context);
357 epoll_check_reopen(epoll_ev);
359 epoll_del_event(epoll_ev, fde);
362 return tevent_common_fd_destructor(fde);
366 add a fd based event
367 return NULL on failure (memory allocation error)
369 static struct tevent_fd *epoll_event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
370 int fd, uint16_t flags,
371 tevent_fd_handler_t handler,
372 void *private_data,
373 const char *handler_name,
374 const char *location)
376 struct epoll_event_context *epoll_ev = talloc_get_type(ev->additional_data,
377 struct epoll_event_context);
378 struct tevent_fd *fde;
380 epoll_check_reopen(epoll_ev);
382 fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
383 handler, private_data,
384 handler_name, location);
385 if (!fde) return NULL;
387 talloc_set_destructor(fde, epoll_event_fd_destructor);
389 epoll_add_event(epoll_ev, fde);
391 return fde;
395 set the fd event flags
397 static void epoll_event_set_fd_flags(struct tevent_fd *fde, uint16_t flags)
399 struct tevent_context *ev;
400 struct epoll_event_context *epoll_ev;
402 if (fde->flags == flags) return;
404 ev = fde->event_ctx;
405 epoll_ev = talloc_get_type(ev->additional_data, struct epoll_event_context);
407 fde->flags = flags;
409 epoll_check_reopen(epoll_ev);
411 epoll_change_event(epoll_ev, fde);
415 do a single event loop using the events defined in ev
417 static int epoll_event_loop_once(struct tevent_context *ev, const char *location)
419 struct epoll_event_context *epoll_ev = talloc_get_type(ev->additional_data,
420 struct epoll_event_context);
421 struct timeval tval;
423 if (ev->signal_events &&
424 tevent_common_check_signal(ev)) {
425 return 0;
428 if (ev->immediate_events &&
429 tevent_common_loop_immediate(ev)) {
430 return 0;
433 tval = tevent_common_loop_timer_delay(ev);
434 if (tevent_timeval_is_zero(&tval)) {
435 return 0;
438 epoll_check_reopen(epoll_ev);
440 return epoll_event_loop(epoll_ev, &tval);
443 static const struct tevent_ops epoll_event_ops = {
444 .context_init = epoll_event_context_init,
445 .add_fd = epoll_event_add_fd,
446 .set_fd_close_fn = tevent_common_fd_set_close_fn,
447 .get_fd_flags = tevent_common_fd_get_flags,
448 .set_fd_flags = epoll_event_set_fd_flags,
449 .add_timer = tevent_common_add_timer,
450 .schedule_immediate = tevent_common_schedule_immediate,
451 .add_signal = tevent_common_add_signal,
452 .loop_once = epoll_event_loop_once,
453 .loop_wait = tevent_common_loop_wait,
456 _PRIVATE_ bool tevent_epoll_init(void)
458 return tevent_register_backend("epoll", &epoll_event_ops);