2 Unix SMB/CIFS implementation.
3 main select loop and event handling
4 Copyright (C) Andrew Tridgell 2003-2005
5 Copyright (C) Stefan Metzmacher 2005-2009
7 ** NOTE! The following LGPL license applies to the tevent
8 ** library. This does NOT imply that all of Samba is released
11 This library is free software; you can redistribute it and/or
12 modify it under the terms of the GNU Lesser General Public
13 License as published by the Free Software Foundation; either
14 version 3 of the License, or (at your option) any later version.
16 This library is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 Lesser General Public License for more details.
21 You should have received a copy of the GNU Lesser General Public
22 License along with this library; if not, see <http://www.gnu.org/licenses/>.
26 #include "system/filesys.h"
27 #include "system/select.h"
29 #include "tevent_util.h"
30 #include "tevent_internal.h"
32 struct select_event_context
{
33 /* a pointer back to the generic event_context */
34 struct tevent_context
*ev
;
36 /* the maximum file descriptor number in fd_events */
39 /* information for exiting from the event loop */
44 create a select_event_context structure.
46 static int select_event_context_init(struct tevent_context
*ev
)
48 struct select_event_context
*select_ev
;
51 * We might be called during tevent_re_initialise()
52 * which means we need to free our old additional_data.
54 TALLOC_FREE(ev
->additional_data
);
56 select_ev
= talloc_zero(ev
, struct select_event_context
);
57 if (!select_ev
) return -1;
60 ev
->additional_data
= select_ev
;
67 static void calc_maxfd(struct select_event_context
*select_ev
)
69 struct tevent_fd
*fde
;
72 for (fde
= select_ev
->ev
->fd_events
; fde
; fde
= fde
->next
) {
73 if (fde
->fd
> select_ev
->maxfd
) {
74 select_ev
->maxfd
= fde
->fd
;
80 /* to mark the ev->maxfd invalid
81 * this means we need to recalculate it
83 #define EVENT_INVALID_MAXFD (-1)
88 static int select_event_fd_destructor(struct tevent_fd
*fde
)
90 struct tevent_context
*ev
= fde
->event_ctx
;
91 struct select_event_context
*select_ev
= NULL
;
94 select_ev
= talloc_get_type(ev
->additional_data
,
95 struct select_event_context
);
97 if (select_ev
->maxfd
== fde
->fd
) {
98 select_ev
->maxfd
= EVENT_INVALID_MAXFD
;
102 return tevent_common_fd_destructor(fde
);
107 return NULL on failure (memory allocation error)
109 static struct tevent_fd
*select_event_add_fd(struct tevent_context
*ev
, TALLOC_CTX
*mem_ctx
,
110 int fd
, uint16_t flags
,
111 tevent_fd_handler_t handler
,
113 const char *handler_name
,
114 const char *location
)
116 struct select_event_context
*select_ev
= talloc_get_type(ev
->additional_data
,
117 struct select_event_context
);
118 struct tevent_fd
*fde
;
120 if (fd
< 0 || fd
>= FD_SETSIZE
) {
125 fde
= tevent_common_add_fd(ev
, mem_ctx
, fd
, flags
,
126 handler
, private_data
,
127 handler_name
, location
);
128 if (!fde
) return NULL
;
130 if ((select_ev
->maxfd
!= EVENT_INVALID_MAXFD
)
131 && (fde
->fd
> select_ev
->maxfd
)) {
132 select_ev
->maxfd
= fde
->fd
;
134 talloc_set_destructor(fde
, select_event_fd_destructor
);
140 event loop handling using select()
142 static int select_event_loop_select(struct select_event_context
*select_ev
, struct timeval
*tvalp
)
145 struct tevent_fd
*fde
;
148 /* we maybe need to recalculate the maxfd */
149 if (select_ev
->maxfd
== EVENT_INVALID_MAXFD
) {
150 calc_maxfd(select_ev
);
156 /* setup any fd events */
157 for (fde
= select_ev
->ev
->fd_events
; fde
; fde
= fde
->next
) {
158 if (fde
->fd
< 0 || fde
->fd
>= FD_SETSIZE
) {
163 if (fde
->flags
& TEVENT_FD_READ
) {
164 FD_SET(fde
->fd
, &r_fds
);
166 if (fde
->flags
& TEVENT_FD_WRITE
) {
167 FD_SET(fde
->fd
, &w_fds
);
171 if (select_ev
->ev
->signal_events
&&
172 tevent_common_check_signal(select_ev
->ev
)) {
176 tevent_trace_point_callback(select_ev
->ev
, TEVENT_TRACE_BEFORE_WAIT
);
177 selrtn
= select(select_ev
->maxfd
+1, &r_fds
, &w_fds
, NULL
, tvalp
);
178 tevent_trace_point_callback(select_ev
->ev
, TEVENT_TRACE_AFTER_WAIT
);
180 if (selrtn
== -1 && errno
== EINTR
&&
181 select_ev
->ev
->signal_events
) {
182 tevent_common_check_signal(select_ev
->ev
);
186 if (selrtn
== -1 && errno
== EBADF
) {
187 /* the socket is dead! this should never
188 happen as the socket should have first been
189 made readable and that should have removed
190 the event, so this must be a bug. This is a
192 tevent_debug(select_ev
->ev
, TEVENT_DEBUG_FATAL
,
193 "ERROR: EBADF on select_event_loop_once\n");
194 select_ev
->exit_code
= EBADF
;
198 if (selrtn
== 0 && tvalp
) {
199 /* we don't care about a possible delay here */
200 tevent_common_loop_timer_delay(select_ev
->ev
);
205 /* at least one file descriptor is ready - check
206 which ones and call the handler, being careful to allow
207 the handler to remove itself when called */
208 for (fde
= select_ev
->ev
->fd_events
; fde
; fde
= fde
->next
) {
211 if (FD_ISSET(fde
->fd
, &r_fds
)) flags
|= TEVENT_FD_READ
;
212 if (FD_ISSET(fde
->fd
, &w_fds
)) flags
|= TEVENT_FD_WRITE
;
214 fde
->handler(select_ev
->ev
, fde
, flags
, fde
->private_data
);
224 do a single event loop using the events defined in ev
226 static int select_event_loop_once(struct tevent_context
*ev
, const char *location
)
228 struct select_event_context
*select_ev
= talloc_get_type(ev
->additional_data
,
229 struct select_event_context
);
232 if (ev
->signal_events
&&
233 tevent_common_check_signal(ev
)) {
237 if (ev
->immediate_events
&&
238 tevent_common_loop_immediate(ev
)) {
242 tval
= tevent_common_loop_timer_delay(ev
);
243 if (tevent_timeval_is_zero(&tval
)) {
247 return select_event_loop_select(select_ev
, &tval
);
250 static const struct tevent_ops select_event_ops
= {
251 .context_init
= select_event_context_init
,
252 .add_fd
= select_event_add_fd
,
253 .set_fd_close_fn
= tevent_common_fd_set_close_fn
,
254 .get_fd_flags
= tevent_common_fd_get_flags
,
255 .set_fd_flags
= tevent_common_fd_set_flags
,
256 .add_timer
= tevent_common_add_timer
,
257 .schedule_immediate
= tevent_common_schedule_immediate
,
258 .add_signal
= tevent_common_add_signal
,
259 .loop_once
= select_event_loop_once
,
260 .loop_wait
= tevent_common_loop_wait
,
263 _PRIVATE_
bool tevent_select_init(void)
265 return tevent_register_backend("select", &select_event_ops
);