2 Unix SMB/CIFS implementation.
3 main select loop and event handling
4 Copyright (C) Andrew Tridgell 2003
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 PLEASE READ THIS BEFORE MODIFYING!
23 This module is a general abstraction for the main select loop and
24 event handling. Do not ever put any localised hacks in here, instead
25 register one of the possible event types and implement that event
28 There are 2 types of event handling that are handled in this module:
30 1) a file descriptor becoming readable or writeable. This is mostly
31 used for network sockets, but can be used for any type of file
32 descriptor. You may only register one handler for each file
33 descriptor/io combination or you will get unpredictable results
34 (this means that you can have a handler for read events, and a
35 separate handler for write events, but not two handlers that are
36 both handling read events)
38 2) a timed event. You can register an event that happens at a
39 specific time. You can register as many of these as you
40 like. They are single shot - add a new timed event in the event
41 handler to get another event.
43 To setup a set of events you first need to create a event_context
44 structure using the function event_context_init(); This returns a
45 'struct event_context' that you use in all subsequent calls.
47 After that you can add/remove events that you are interested in
48 using event_add_*() and talloc_free()
50 Finally, you call event_loop_wait_once() to block waiting for one of the
51 events to occor or event_loop_wait() which will loop
57 #include "lib/events/events.h"
58 #include "lib/events/events_internal.h"
59 #include "lib/util/dlinklist.h"
60 #include "param/param.h"
62 struct event_ops_list {
63 struct event_ops_list *next, *prev;
65 const struct event_ops *ops;
68 /* list of registered event backends */
69 static struct event_ops_list *event_backends;
71 static char *event_default_backend = NULL;
74 register an events backend
76 bool event_register_backend(const char *name, const struct event_ops *ops)
78 struct event_ops_list *e;
79 e = talloc(talloc_autofree_context(), struct event_ops_list);
80 if (e == NULL) return false;
83 DLIST_ADD(event_backends, e);
88 set the default event backend
90 void event_set_default_backend(const char *backend)
92 if (event_default_backend) free(event_default_backend);
93 event_default_backend = strdup(backend);
97 initialise backends if not already done
99 static void event_backend_init(void)
102 NTSTATUS s4_events_standard_init(void);
103 NTSTATUS s4_events_select_init(void);
104 NTSTATUS s4_events_epoll_init(void);
105 NTSTATUS s4_events_aio_init(void);
106 init_module_fn static_init[] = { STATIC_LIBEVENTS_MODULES };
107 if (event_backends) return;
108 run_init_functions(static_init);
110 bool events_standard_init(void);
111 bool events_select_init(void);
112 events_select_init();
113 events_standard_init();
114 #if HAVE_EVENTS_EPOLL
116 bool events_epoll_init(void);
124 list available backends
126 const char **event_backend_list(TALLOC_CTX *mem_ctx)
128 const char **list = NULL;
129 struct event_ops_list *e;
131 event_backend_init();
133 for (e=event_backends;e;e=e->next) {
134 list = str_list_add(list, e->name);
137 talloc_steal(mem_ctx, list);
143 create a event_context structure for a specific implemementation.
144 This must be the first events call, and all subsequent calls pass
145 this event_context as the first element. Event handlers also
146 receive this as their first argument.
148 This function is for allowing third-party-applications to hook in gluecode
149 to their own event loop code, so that they can make async usage of our client libs
151 NOTE: use event_context_init() inside of samba!
153 static struct event_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
154 const struct event_ops *ops)
156 struct event_context *ev;
159 ev = talloc_zero(mem_ctx, struct event_context);
160 if (!ev) return NULL;
164 ret = ev->ops->context_init(ev);
174 create a event_context structure. This must be the first events
175 call, and all subsequent calls pass this event_context as the first
176 element. Event handlers also receive this as their first argument.
178 struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name)
180 struct event_ops_list *e;
182 event_backend_init();
185 name = event_default_backend;
191 for (e=event_backends;e;e=e->next) {
192 if (strcmp(name, e->name) == 0) {
193 return event_context_init_ops(mem_ctx, e->ops);
201 create a event_context structure. This must be the first events
202 call, and all subsequent calls pass this event_context as the first
203 element. Event handlers also receive this as their first argument.
205 struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
207 return event_context_init_byname(mem_ctx, NULL);
212 return NULL on failure (memory allocation error)
214 if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
215 the returned fd_event context is freed
217 struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
218 int fd, uint16_t flags, event_fd_handler_t handler,
221 return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
227 struct aio_event *event_add_aio(struct event_context *ev,
230 event_aio_handler_t handler,
233 if (ev->ops->add_aio == NULL) return NULL;
234 return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
238 return the fd event flags
240 uint16_t event_get_fd_flags(struct fd_event *fde)
243 return fde->event_ctx->ops->get_fd_flags(fde);
247 set the fd event flags
249 void event_set_fd_flags(struct fd_event *fde, uint16_t flags)
252 fde->event_ctx->ops->set_fd_flags(fde, flags);
257 return NULL on failure
259 struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx,
260 struct timeval next_event,
261 event_timed_handler_t handler,
264 return ev->ops->add_timed(ev, mem_ctx, next_event, handler, private_data);
270 sa_flags are flags to sigaction(2)
272 return NULL on failure
274 struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
277 event_signal_handler_t handler,
280 return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
284 do a single event loop using the events defined in ev
286 _PUBLIC_ int event_loop_once(struct event_context *ev)
288 return ev->ops->loop_once(ev);
292 return on failure or (with 0) if all fd events are removed
294 int event_loop_wait(struct event_context *ev)
296 return ev->ops->loop_wait(ev);
300 find an event context that is a parent of the given memory context,
301 or create a new event context as a child of the given context if
304 This should be used in preference to event_context_init() in places
305 where you would prefer to use the existing event context if possible
306 (which is most situations)
308 struct event_context *event_context_find(TALLOC_CTX *mem_ctx)
310 struct event_context *ev = talloc_find_parent_bytype(mem_ctx, struct event_context);
312 ev = event_context_init(mem_ctx);