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 tevent_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 tevent_ops_list {
61 struct tevent_ops_list *next, *prev;
63 const struct tevent_ops *ops;
66 /* list of registered event backends */
67 static struct tevent_ops_list *tevent_backends = NULL;
68 static char *tevent_default_backend = NULL;
71 register an events backend
73 bool tevent_register_backend(const char *name, const struct tevent_ops *ops)
75 struct tevent_ops_list *e;
77 for (e = tevent_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 tevent_ops_list);
85 if (e == NULL) return false;
89 DLIST_ADD(tevent_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 tevent_backend_init(void)
109 tevent_select_init();
110 tevent_standard_init();
114 #ifdef HAVE_LINUX_AIO
120 list available backends
122 const char **tevent_backend_list(TALLOC_CTX *mem_ctx)
124 const char **list = NULL;
125 struct tevent_ops_list *e;
127 tevent_backend_init();
129 for (e=tevent_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 tevent_context_init() inside of samba!
149 static struct tevent_context *tevent_context_init_ops(TALLOC_CTX *mem_ctx,
150 const struct tevent_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 *tevent_context_init_byname(TALLOC_CTX *mem_ctx,
177 struct tevent_ops_list *e;
179 tevent_backend_init();
182 name = tevent_default_backend;
188 for (e=tevent_backends;e;e=e->next) {
189 if (strcmp(name, e->name) == 0) {
190 return tevent_context_init_ops(mem_ctx, e->ops);
198 create a event_context structure. This must be the first events
199 call, and all subsequent calls pass this event_context as the first
200 element. Event handlers also receive this as their first argument.
202 struct tevent_context *tevent_context_init(TALLOC_CTX *mem_ctx)
204 return tevent_context_init_byname(mem_ctx, NULL);
209 return NULL on failure (memory allocation error)
211 if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
212 the returned fd_event context is freed
214 struct tevent_fd *event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
215 int fd, uint16_t flags, event_fd_handler_t handler,
218 return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
224 struct aio_event *event_add_aio(struct tevent_context *ev,
227 event_aio_handler_t handler,
230 if (ev->ops->add_aio == NULL) return NULL;
231 return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
235 return the fd event flags
237 uint16_t tevent_fd_get_flags(struct tevent_fd *fde)
240 return fde->event_ctx->ops->get_fd_flags(fde);
244 set the fd event flags
246 void tevent_fd_set_flags(struct tevent_fd *fde, uint16_t flags)
249 fde->event_ctx->ops->set_fd_flags(fde, flags);
254 return NULL on failure
256 struct tevent_timer *event_add_timed(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
257 struct timeval next_event,
258 event_timed_handler_t handler,
261 return ev->ops->add_timer(ev, mem_ctx, next_event, handler, private_data);
267 sa_flags are flags to sigaction(2)
269 return NULL on failure
271 struct signal_event *event_add_signal(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
274 event_signal_handler_t handler,
277 return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
281 do a single event loop using the events defined in ev
283 int tevent_loop_once(struct tevent_context *ev)
285 return ev->ops->loop_once(ev);
289 return on failure or (with 0) if all fd events are removed
291 int tevent_loop_wait(struct tevent_context *ev)
293 return ev->ops->loop_wait(ev);