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"
65 struct event_ops_list {
66 struct event_ops_list *next, *prev;
68 const struct event_ops *ops;
71 /* list of registered event backends */
72 static struct event_ops_list *event_backends;
74 static char *event_default_backend = NULL;
77 register an events backend
79 bool event_register_backend(const char *name, const struct event_ops *ops)
81 struct event_ops_list *e;
82 e = talloc(talloc_autofree_context(), struct event_ops_list);
83 if (e == NULL) return false;
86 DLIST_ADD(event_backends, e);
91 set the default event backend
93 void event_set_default_backend(const char *backend)
95 if (event_default_backend) free(event_default_backend);
96 event_default_backend = strdup(backend);
100 initialise backends if not already done
102 static void event_backend_init(void)
105 NTSTATUS s4_events_standard_init(void);
106 NTSTATUS s4_events_select_init(void);
107 NTSTATUS s4_events_epoll_init(void);
108 NTSTATUS s4_events_aio_init(void);
109 init_module_fn static_init[] = { STATIC_LIBEVENTS_MODULES };
110 if (event_backends) return;
111 run_init_functions(static_init);
113 bool events_standard_init(void);
114 bool events_select_init(void);
115 events_select_init();
116 events_standard_init();
117 #if HAVE_EVENTS_EPOLL
119 bool events_epoll_init(void);
127 list available backends
129 const char **event_backend_list(TALLOC_CTX *mem_ctx)
131 const char **list = NULL;
132 struct event_ops_list *e;
134 event_backend_init();
136 for (e=event_backends;e;e=e->next) {
137 list = str_list_add(list, e->name);
140 talloc_steal(mem_ctx, list);
146 create a event_context structure for a specific implemementation.
147 This must be the first events call, and all subsequent calls pass
148 this event_context as the first element. Event handlers also
149 receive this as their first argument.
151 This function is for allowing third-party-applications to hook in gluecode
152 to their own event loop code, so that they can make async usage of our client libs
154 NOTE: use event_context_init() inside of samba!
156 static struct event_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
157 const struct event_ops *ops)
159 struct event_context *ev;
162 ev = talloc_zero(mem_ctx, struct event_context);
163 if (!ev) return NULL;
167 ret = ev->ops->context_init(ev);
177 create a event_context structure. This must be the first events
178 call, and all subsequent calls pass this event_context as the first
179 element. Event handlers also receive this as their first argument.
181 struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name)
183 struct event_ops_list *e;
185 event_backend_init();
188 name = event_default_backend;
194 for (e=event_backends;e;e=e->next) {
195 if (strcmp(name, e->name) == 0) {
196 return event_context_init_ops(mem_ctx, e->ops);
204 create a event_context structure. This must be the first events
205 call, and all subsequent calls pass this event_context as the first
206 element. Event handlers also receive this as their first argument.
208 struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
210 DEBUG(0, ("New event context requested. Parent: [%s:%p]\n",
211 mem_ctx?talloc_get_name(mem_ctx):"NULL", mem_ctx));
212 return event_context_init_byname(mem_ctx, NULL);
217 return NULL on failure (memory allocation error)
219 if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
220 the returned fd_event context is freed
222 struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
223 int fd, uint16_t flags, event_fd_handler_t handler,
226 return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
232 struct aio_event *event_add_aio(struct event_context *ev,
235 event_aio_handler_t handler,
238 if (ev->ops->add_aio == NULL) return NULL;
239 return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
243 return the fd event flags
245 uint16_t event_get_fd_flags(struct fd_event *fde)
248 return fde->event_ctx->ops->get_fd_flags(fde);
252 set the fd event flags
254 void event_set_fd_flags(struct fd_event *fde, uint16_t flags)
257 fde->event_ctx->ops->set_fd_flags(fde, flags);
262 return NULL on failure
264 struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx,
265 struct timeval next_event,
266 event_timed_handler_t handler,
269 return ev->ops->add_timed(ev, mem_ctx, next_event, handler, private_data);
275 sa_flags are flags to sigaction(2)
277 return NULL on failure
279 struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
282 event_signal_handler_t handler,
285 return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
289 do a single event loop using the events defined in ev
291 _PUBLIC_ int event_loop_once(struct event_context *ev)
293 return ev->ops->loop_once(ev);
297 return on failure or (with 0) if all fd events are removed
299 int event_loop_wait(struct event_context *ev)
301 return ev->ops->loop_wait(ev);
305 find an event context that is a parent of the given memory context,
306 or create a new event context as a child of the given context if
309 This should be used in preference to event_context_init() in places
310 where you would prefer to use the existing event context if possible
311 (which is most situations)
313 struct event_context *event_context_find(TALLOC_CTX *mem_ctx)
315 struct event_context *ev = talloc_find_parent_bytype(mem_ctx, struct event_context);
317 ev = event_context_init(mem_ctx);