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/>.
25 #include <atalk/tevent.h>
27 #include "tevent_util.h"
28 #include "tevent_internal.h"
30 struct select_event_context {
31 /* a pointer back to the generic event_context */
32 struct tevent_context *ev;
34 /* the maximum file descriptor number in fd_events */
37 /* information for exiting from the event loop */
42 create a select_event_context structure.
44 static int select_event_context_init(struct tevent_context *ev)
46 struct select_event_context *select_ev;
48 select_ev = talloc_zero(ev, struct select_event_context);
49 if (!select_ev) return -1;
52 ev->additional_data = select_ev;
59 static void calc_maxfd(struct select_event_context *select_ev)
61 struct tevent_fd *fde;
64 for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
65 if (fde->fd > select_ev->maxfd) {
66 select_ev->maxfd = fde->fd;
72 /* to mark the ev->maxfd invalid
73 * this means we need to recalculate it
75 #define EVENT_INVALID_MAXFD (-1)
80 static int select_event_fd_destructor(struct tevent_fd *fde)
82 struct tevent_context *ev = fde->event_ctx;
83 struct select_event_context *select_ev = NULL;
86 select_ev = talloc_get_type(ev->additional_data,
87 struct select_event_context);
89 if (select_ev->maxfd == fde->fd) {
90 select_ev->maxfd = EVENT_INVALID_MAXFD;
94 return tevent_common_fd_destructor(fde);
99 return NULL on failure (memory allocation error)
101 static struct tevent_fd *select_event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
102 int fd, uint16_t flags,
103 tevent_fd_handler_t handler,
105 const char *handler_name,
106 const char *location)
108 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
109 struct select_event_context);
110 struct tevent_fd *fde;
112 fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
113 handler, private_data,
114 handler_name, location);
115 if (!fde) return NULL;
117 if (fde->fd > select_ev->maxfd) {
118 select_ev->maxfd = fde->fd;
120 talloc_set_destructor(fde, select_event_fd_destructor);
126 event loop handling using select()
128 static int select_event_loop_select(struct select_event_context *select_ev, struct timeval *tvalp)
131 struct tevent_fd *fde;
134 /* we maybe need to recalculate the maxfd */
135 if (select_ev->maxfd == EVENT_INVALID_MAXFD) {
136 calc_maxfd(select_ev);
142 /* setup any fd events */
143 for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
144 if (fde->flags & TEVENT_FD_READ) {
145 FD_SET(fde->fd, &r_fds);
147 if (fde->flags & TEVENT_FD_WRITE) {
148 FD_SET(fde->fd, &w_fds);
152 if (select_ev->ev->signal_events &&
153 tevent_common_check_signal(select_ev->ev)) {
157 selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, NULL, tvalp);
159 if (selrtn == -1 && errno == EINTR &&
160 select_ev->ev->signal_events) {
161 tevent_common_check_signal(select_ev->ev);
165 if (selrtn == -1 && errno == EBADF) {
166 /* the socket is dead! this should never
167 happen as the socket should have first been
168 made readable and that should have removed
169 the event, so this must be a bug. This is a
171 tevent_debug(select_ev->ev, TEVENT_DEBUG_FATAL,
172 "ERROR: EBADF on select_event_loop_once\n");
173 select_ev->exit_code = EBADF;
177 if (selrtn == 0 && tvalp) {
178 /* we don't care about a possible delay here */
179 tevent_common_loop_timer_delay(select_ev->ev);
184 /* at least one file descriptor is ready - check
185 which ones and call the handler, being careful to allow
186 the handler to remove itself when called */
187 for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
190 if (FD_ISSET(fde->fd, &r_fds)) flags |= TEVENT_FD_READ;
191 if (FD_ISSET(fde->fd, &w_fds)) flags |= TEVENT_FD_WRITE;
193 fde->handler(select_ev->ev, fde, flags, fde->private_data);
203 do a single event loop using the events defined in ev
205 static int select_event_loop_once(struct tevent_context *ev, const char *location)
207 struct select_event_context *select_ev = talloc_get_type(ev->additional_data,
208 struct select_event_context);
211 if (ev->signal_events &&
212 tevent_common_check_signal(ev)) {
216 if (ev->immediate_events &&
217 tevent_common_loop_immediate(ev)) {
221 tval = tevent_common_loop_timer_delay(ev);
222 if (tevent_timeval_is_zero(&tval)) {
226 return select_event_loop_select(select_ev, &tval);
229 static const struct tevent_ops select_event_ops = {
230 .context_init = select_event_context_init,
231 .add_fd = select_event_add_fd,
232 .set_fd_close_fn = tevent_common_fd_set_close_fn,
233 .get_fd_flags = tevent_common_fd_get_flags,
234 .set_fd_flags = tevent_common_fd_set_flags,
235 .add_timer = tevent_common_add_timer,
236 .schedule_immediate = tevent_common_schedule_immediate,
237 .add_signal = tevent_common_add_signal,
238 .loop_once = select_event_loop_once,
239 .loop_wait = tevent_common_loop_wait,
242 bool tevent_select_init(void)
244 return tevent_register_backend("select", &select_event_ops);