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
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 This is SAMBA's default event loop code
27 #include "system/filesys.h"
28 #include "system/select.h"
30 #include "events_util.h"
31 #include "events_internal.h"
33 struct select_event_context {
34 /* a pointer back to the generic event_context */
35 struct event_context *ev;
37 /* list of filedescriptor events */
38 struct fd_event *fd_events;
40 /* list of timed events */
41 struct timed_event *timed_events;
43 /* the maximum file descriptor number in fd_events */
46 /* information for exiting from the event loop */
49 /* this is incremented when the loop over events causes something which
50 could change the events yet to be processed */
51 uint32_t destruction_count;
55 create a select_event_context structure.
57 static int select_event_context_init(struct event_context *ev)
59 struct select_event_context *select_ev;
61 select_ev = talloc_zero(ev, struct select_event_context);
62 if (!select_ev) return -1;
65 ev->additional_data = select_ev;
72 static void calc_maxfd(struct select_event_context *select_ev)
77 for (fde = select_ev->fd_events; fde; fde = fde->next) {
78 if (fde->fd > select_ev->maxfd) {
79 select_ev->maxfd = fde->fd;
85 /* to mark the ev->maxfd invalid
86 * this means we need to recalculate it
88 #define EVENT_INVALID_MAXFD (-1)
93 static int select_event_fd_destructor(struct fd_event *fde)
95 struct event_context *ev = fde->event_ctx;
96 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
97 struct select_event_context);
99 if (select_ev->maxfd == fde->fd) {
100 select_ev->maxfd = EVENT_INVALID_MAXFD;
103 DLIST_REMOVE(select_ev->fd_events, fde);
104 select_ev->destruction_count++;
106 if (fde->flags & EVENT_FD_AUTOCLOSE) {
116 return NULL on failure (memory allocation error)
118 static struct fd_event *select_event_add_fd(struct event_context *ev, TALLOC_CTX *mem_ctx,
119 int fd, uint16_t flags,
120 event_fd_handler_t handler,
123 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
124 struct select_event_context);
125 struct fd_event *fde;
127 fde = talloc(mem_ctx?mem_ctx:ev, struct fd_event);
128 if (!fde) return NULL;
133 fde->handler = handler;
134 fde->private_data = private_data;
135 fde->additional_flags = 0;
136 fde->additional_data = NULL;
138 DLIST_ADD(select_ev->fd_events, fde);
139 if (fde->fd > select_ev->maxfd) {
140 select_ev->maxfd = fde->fd;
142 talloc_set_destructor(fde, select_event_fd_destructor);
149 return the fd event flags
151 static uint16_t select_event_get_fd_flags(struct fd_event *fde)
157 set the fd event flags
159 static void select_event_set_fd_flags(struct fd_event *fde, uint16_t flags)
161 struct event_context *ev;
162 struct select_event_context *select_ev;
164 if (fde->flags == flags) return;
167 select_ev = talloc_get_type(ev->additional_data, struct select_event_context);
173 event loop handling using select()
175 static int select_event_loop_select(struct select_event_context *select_ev, struct timeval *tvalp)
178 struct fd_event *fde;
180 uint32_t destruction_count = ++select_ev->destruction_count;
182 /* we maybe need to recalculate the maxfd */
183 if (select_ev->maxfd == EVENT_INVALID_MAXFD) {
184 calc_maxfd(select_ev);
190 /* setup any fd events */
191 for (fde = select_ev->fd_events; fde; fde = fde->next) {
192 if (fde->flags & EVENT_FD_READ) {
193 FD_SET(fde->fd, &r_fds);
195 if (fde->flags & EVENT_FD_WRITE) {
196 FD_SET(fde->fd, &w_fds);
200 if (select_ev->ev->num_signal_handlers &&
201 common_event_check_signal(select_ev->ev)) {
205 selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
207 if (selrtn == -1 && errno == EINTR &&
208 select_ev->ev->num_signal_handlers) {
209 common_event_check_signal(select_ev->ev);
213 if (selrtn == -1 && errno == EBADF) {
214 /* the socket is dead! this should never
215 happen as the socket should have first been
216 made readable and that should have removed
217 the event, so this must be a bug. This is a
219 ev_debug(select_ev->ev, EV_DEBUG_FATAL,
220 "ERROR: EBADF on select_event_loop_once\n");
221 select_ev->exit_code = EBADF;
225 if (selrtn == 0 && tvalp) {
226 /* we don't care about a possible delay here */
227 common_event_loop_timer_delay(select_ev->ev);
232 /* at least one file descriptor is ready - check
233 which ones and call the handler, being careful to allow
234 the handler to remove itself when called */
235 for (fde = select_ev->fd_events; fde; fde = fde->next) {
238 if (FD_ISSET(fde->fd, &r_fds)) flags |= EVENT_FD_READ;
239 if (FD_ISSET(fde->fd, &w_fds)) flags |= EVENT_FD_WRITE;
241 fde->handler(select_ev->ev, fde, flags, fde->private_data);
242 if (destruction_count != select_ev->destruction_count) {
253 do a single event loop using the events defined in ev
255 static int select_event_loop_once(struct event_context *ev)
257 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
258 struct select_event_context);
261 tval = common_event_loop_timer_delay(ev);
262 if (ev_timeval_is_zero(&tval)) {
266 return select_event_loop_select(select_ev, &tval);
270 return on failure or (with 0) if all fd events are removed
272 static int select_event_loop_wait(struct event_context *ev)
274 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
275 struct select_event_context);
276 select_ev->exit_code = 0;
278 while (select_ev->fd_events && select_ev->exit_code == 0) {
279 if (select_event_loop_once(ev) != 0) {
284 return select_ev->exit_code;
287 static const struct event_ops select_event_ops = {
288 .context_init = select_event_context_init,
289 .add_fd = select_event_add_fd,
290 .get_fd_flags = select_event_get_fd_flags,
291 .set_fd_flags = select_event_set_fd_flags,
292 .add_timed = common_event_add_timed,
293 .add_signal = common_event_add_signal,
294 .loop_once = select_event_loop_once,
295 .loop_wait = select_event_loop_wait,
298 bool events_select_init(void)
300 return event_register_backend("select", &select_event_ops);