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 tevent_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 tevent_loop_wait_once() to block waiting for one of the
51 events to occor or tevent_loop_wait() which will loop
57 #include "tevent_internal.h"
58 #include "tevent_util.h"
60 struct event_ops_list {
61 struct event_ops_list *next, *prev;
63 const struct event_ops *ops;
66 /* list of registered event backends */
67 static struct event_ops_list *event_backends = NULL;
68 static char *tevent_default_backend = NULL;
71 register an events backend
73 bool event_register_backend(const char *name, const struct event_ops *ops)
75 struct event_ops_list *e;
77 for (e = event_backends; e != NULL; e = e->next) {
78 if (0 == strcmp(e->name, name)) {
79 /* already registered, skip it */
84 e = talloc(talloc_autofree_context(), struct event_ops_list);
85 if (e == NULL) return false;
89 DLIST_ADD(event_backends, e);
95 set the default event backend
97 void tevent_set_default_backend(const char *backend)
99 talloc_free(tevent_default_backend);
100 tevent_default_backend = talloc_strdup(talloc_autofree_context(),
105 initialise backends if not already done
107 static void event_backend_init(void)
109 events_select_init();
110 events_standard_init();
111 #if HAVE_EVENTS_EPOLL
120 list available backends
122 const char **event_backend_list(TALLOC_CTX *mem_ctx)
124 const char **list = NULL;
125 struct event_ops_list *e;
127 event_backend_init();
129 for (e=event_backends;e;e=e->next) {
130 list = ev_str_list_add(list, e->name);
133 talloc_steal(mem_ctx, list);
139 create a event_context structure for a specific implemementation.
140 This must be the first events call, and all subsequent calls pass
141 this event_context as the first element. Event handlers also
142 receive this as their first argument.
144 This function is for allowing third-party-applications to hook in gluecode
145 to their own event loop code, so that they can make async usage of our client libs
147 NOTE: use event_context_init() inside of samba!
149 static struct tevent_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
150 const struct event_ops *ops)
152 struct tevent_context *ev;
155 ev = talloc_zero(mem_ctx, struct tevent_context);
156 if (!ev) return NULL;
160 ret = ev->ops->context_init(ev);
170 create a event_context structure. This must be the first events
171 call, and all subsequent calls pass this event_context as the first
172 element. Event handlers also receive this as their first argument.
174 struct tevent_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name)
176 struct event_ops_list *e;
178 event_backend_init();
181 name = tevent_default_backend;
187 for (e=event_backends;e;e=e->next) {
188 if (strcmp(name, e->name) == 0) {
189 return event_context_init_ops(mem_ctx, e->ops);
197 create a event_context structure. This must be the first events
198 call, and all subsequent calls pass this event_context as the first
199 element. Event handlers also receive this as their first argument.
201 struct tevent_context *event_context_init(TALLOC_CTX *mem_ctx)
203 return event_context_init_byname(mem_ctx, NULL);
208 return NULL on failure (memory allocation error)
210 if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
211 the returned fd_event context is freed
213 struct tevent_fd *event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
214 int fd, uint16_t flags, event_fd_handler_t handler,
217 return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
223 struct aio_event *event_add_aio(struct tevent_context *ev,
226 event_aio_handler_t handler,
229 if (ev->ops->add_aio == NULL) return NULL;
230 return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
234 return the fd event flags
236 uint16_t tevent_fd_get_flags(struct tevent_fd *fde)
239 return fde->event_ctx->ops->get_fd_flags(fde);
243 set the fd event flags
245 void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags)
248 fde->event_ctx->ops->set_fd_flags(fde, flags);
253 return NULL on failure
255 struct tevent_timer *event_add_timed(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
256 struct timeval next_event,
257 event_timed_handler_t handler,
260 return ev->ops->add_timer(ev, mem_ctx, next_event, handler, private_data);
266 sa_flags are flags to sigaction(2)
268 return NULL on failure
270 struct signal_event *event_add_signal(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
273 event_signal_handler_t handler,
276 return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
280 do a single event loop using the events defined in ev
282 int tevent_loop_once(struct tevent_context *ev)
284 return ev->ops->loop_once(ev);
288 return on failure or (with 0) if all fd events are removed
290 int tevent_loop_wait(struct tevent_context *ev)
292 return ev->ops->loop_wait(ev);