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"
64 struct event_ops_list {
65 struct event_ops_list *next, *prev;
67 const struct event_ops *ops;
70 /* list of registered event backends */
71 static struct event_ops_list *event_backends;
73 static char *event_default_backend = NULL;
76 register an events backend
78 bool event_register_backend(const char *name, const struct event_ops *ops)
80 struct event_ops_list *e;
81 e = talloc(talloc_autofree_context(), struct event_ops_list);
82 if (e == NULL) return False;
85 DLIST_ADD(event_backends, e);
90 set the default event backend
92 void event_set_default_backend(const char *backend)
94 if (event_default_backend) free(event_default_backend);
95 event_default_backend = strdup(backend);
99 initialise backends if not already done
101 static void event_backend_init(void)
104 init_module_fn static_init[] = STATIC_LIBEVENTS_MODULES;
105 init_module_fn *shared_init;
106 if (event_backends) return;
107 shared_init = load_samba_modules(NULL, "LIBEVENTS");
108 run_init_functions(static_init);
109 run_init_functions(shared_init);
111 bool events_standard_init(void);
112 bool events_select_init(void);
113 events_select_init();
114 events_standard_init();
115 #if HAVE_EVENTS_EPOLL
117 bool events_epoll_init(void);
125 list available backends
127 const char **event_backend_list(TALLOC_CTX *mem_ctx)
129 const char **list = NULL;
130 struct event_ops_list *e;
132 event_backend_init();
134 for (e=event_backends;e;e=e->next) {
135 list = str_list_add(list, e->name);
138 talloc_steal(mem_ctx, list);
144 create a event_context structure for a specific implemementation.
145 This must be the first events call, and all subsequent calls pass
146 this event_context as the first element. Event handlers also
147 receive this as their first argument.
149 This function is for allowing third-party-applications to hook in gluecode
150 to their own event loop code, so that they can make async usage of our client libs
152 NOTE: use event_context_init() inside of samba!
154 static struct event_context *event_context_init_ops(TALLOC_CTX *mem_ctx,
155 const struct event_ops *ops)
157 struct event_context *ev;
160 ev = talloc_zero(mem_ctx, struct event_context);
161 if (!ev) return NULL;
165 ret = ev->ops->context_init(ev);
175 create a event_context structure. This must be the first events
176 call, and all subsequent calls pass this event_context as the first
177 element. Event handlers also receive this as their first argument.
179 struct event_context *event_context_init_byname(TALLOC_CTX *mem_ctx, const char *name)
181 struct event_ops_list *e;
183 event_backend_init();
187 name = lp_parm_string(-1, "event", "backend");
191 name = event_default_backend;
197 for (e=event_backends;e;e=e->next) {
198 if (strcmp(name, e->name) == 0) {
199 return event_context_init_ops(mem_ctx, e->ops);
207 create a event_context structure. This must be the first events
208 call, and all subsequent calls pass this event_context as the first
209 element. Event handlers also receive this as their first argument.
211 struct event_context *event_context_init(TALLOC_CTX *mem_ctx)
213 return event_context_init_byname(mem_ctx, NULL);
218 return NULL on failure (memory allocation error)
220 if flags contains EVENT_FD_AUTOCLOSE then the fd will be closed when
221 the returned fd_event context is freed
223 struct fd_event *event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
224 int fd, uint16_t flags, event_fd_handler_t handler,
227 return ev->ops->add_fd(ev, mem_ctx, fd, flags, handler, private_data);
233 struct aio_event *event_add_aio(struct event_context *ev,
236 event_aio_handler_t handler,
239 if (ev->ops->add_aio == NULL) return NULL;
240 return ev->ops->add_aio(ev, mem_ctx, iocb, handler, private_data);
244 return the fd event flags
246 uint16_t event_get_fd_flags(struct fd_event *fde)
249 return fde->event_ctx->ops->get_fd_flags(fde);
253 set the fd event flags
255 void event_set_fd_flags(struct fd_event *fde, uint16_t flags)
258 fde->event_ctx->ops->set_fd_flags(fde, flags);
263 return NULL on failure
265 struct timed_event *event_add_timed(struct event_context *ev, TALLOC_CTX *mem_ctx,
266 struct timeval next_event,
267 event_timed_handler_t handler,
270 return ev->ops->add_timed(ev, mem_ctx, next_event, handler, private_data);
276 sa_flags are flags to sigaction(2)
278 return NULL on failure
280 struct signal_event *event_add_signal(struct event_context *ev, TALLOC_CTX *mem_ctx,
283 event_signal_handler_t handler,
286 return ev->ops->add_signal(ev, mem_ctx, signum, sa_flags, handler, private_data);
290 do a single event loop using the events defined in ev
292 _PUBLIC_ int event_loop_once(struct event_context *ev)
294 return ev->ops->loop_once(ev);
298 return on failure or (with 0) if all fd events are removed
300 int event_loop_wait(struct event_context *ev)
302 return ev->ops->loop_wait(ev);
306 find an event context that is a parent of the given memory context,
307 or create a new event context as a child of the given context if
310 This should be used in preference to event_context_init() in places
311 where you would prefer to use the existing event context if possible
312 (which is most situations)
314 struct event_context *event_context_find(TALLOC_CTX *mem_ctx)
316 struct event_context *ev = talloc_find_parent_bytype(mem_ctx, struct event_context);
318 ev = event_context_init(mem_ctx);