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 */
41 create a select_event_context structure.
43 static int select_event_context_init(struct tevent_context *ev)
45 struct select_event_context *select_ev;
48 * We might be called during tevent_re_initialise()
49 * which means we need to free our old additional_data.
51 TALLOC_FREE(ev->additional_data);
53 select_ev = talloc_zero(ev, struct select_event_context);
54 if (!select_ev) return -1;
57 ev->additional_data = select_ev;
64 static void calc_maxfd(struct select_event_context *select_ev)
66 struct tevent_fd *fde;
69 for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
70 if (fde->fd > select_ev->maxfd) {
71 select_ev->maxfd = fde->fd;
77 /* to mark the ev->maxfd invalid
78 * this means we need to recalculate it
80 #define EVENT_INVALID_MAXFD (-1)
85 static int select_event_fd_destructor(struct tevent_fd *fde)
87 struct tevent_context *ev = fde->event_ctx;
88 struct select_event_context *select_ev = NULL;
91 select_ev = talloc_get_type_abort(ev->additional_data,
92 struct select_event_context);
94 if (select_ev->maxfd == fde->fd) {
95 select_ev->maxfd = EVENT_INVALID_MAXFD;
99 return tevent_common_fd_destructor(fde);
104 return NULL on failure (memory allocation error)
106 static struct tevent_fd *select_event_add_fd(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
107 int fd, uint16_t flags,
108 tevent_fd_handler_t handler,
110 const char *handler_name,
111 const char *location)
113 struct select_event_context *select_ev =
114 talloc_get_type_abort(ev->additional_data,
115 struct select_event_context);
116 struct tevent_fd *fde;
118 if (fd < 0 || fd >= FD_SETSIZE) {
123 fde = tevent_common_add_fd(ev, mem_ctx, fd, flags,
124 handler, private_data,
125 handler_name, location);
126 if (!fde) return NULL;
128 if ((select_ev->maxfd != EVENT_INVALID_MAXFD)
129 && (fde->fd > select_ev->maxfd)) {
130 select_ev->maxfd = fde->fd;
132 talloc_set_destructor(fde, select_event_fd_destructor);
138 event loop handling using select()
140 static int select_event_loop_select(struct select_event_context *select_ev, struct timeval *tvalp)
142 fd_set r_fds, w_fds, e_fds;
143 struct tevent_fd *fde;
147 /* we maybe need to recalculate the maxfd */
148 if (select_ev->maxfd == EVENT_INVALID_MAXFD) {
149 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) {
159 tevent_debug(select_ev->ev, TEVENT_DEBUG_FATAL,
160 "ERROR: EBADF fd[%d] >= %d "
161 "select_event_loop_once\n",
162 fde->fd, FD_SETSIZE);
167 if (fde->flags & TEVENT_FD_READ) {
168 FD_SET(fde->fd, &r_fds);
169 FD_SET(fde->fd, &e_fds);
171 if (fde->flags & TEVENT_FD_WRITE) {
172 FD_SET(fde->fd, &w_fds);
176 if (select_ev->ev->signal_events &&
177 tevent_common_check_signal(select_ev->ev)) {
181 tevent_trace_point_callback(select_ev->ev, TEVENT_TRACE_BEFORE_WAIT);
182 selrtn = select(select_ev->maxfd+1, &r_fds, &w_fds, &e_fds, tvalp);
183 select_errno = errno;
184 tevent_trace_point_callback(select_ev->ev, TEVENT_TRACE_AFTER_WAIT);
186 if (selrtn == -1 && select_errno == EINTR &&
187 select_ev->ev->signal_events) {
188 tevent_common_check_signal(select_ev->ev);
192 if (selrtn == -1 && select_errno == EBADF) {
193 /* the socket is dead! this should never
194 happen as the socket should have first been
195 made readable and that should have removed
196 the event, so this must be a bug. This is a
198 tevent_debug(select_ev->ev, TEVENT_DEBUG_FATAL,
199 "ERROR: EBADF on select_event_loop_once\n");
200 errno = select_errno;
204 if (selrtn == 0 && tvalp) {
205 /* we don't care about a possible delay here */
206 tevent_common_loop_timer_delay(select_ev->ev);
211 /* at least one file descriptor is ready - check
212 which ones and call the handler, being careful to allow
213 the handler to remove itself when called */
214 for (fde = select_ev->ev->fd_events; fde; fde = fde->next) {
217 if (FD_ISSET(fde->fd, &r_fds) && (fde->flags & TEVENT_FD_READ)) {
218 flags |= TEVENT_FD_READ;
220 if (FD_ISSET(fde->fd, &w_fds) && (fde->flags & TEVENT_FD_WRITE)) {
221 flags |= TEVENT_FD_WRITE;
224 DLIST_DEMOTE(select_ev->ev->fd_events, fde);
225 fde->handler(select_ev->ev, fde, flags, fde->private_data);
235 do a single event loop using the events defined in ev
237 static int select_event_loop_once(struct tevent_context *ev, const char *location)
239 struct select_event_context *select_ev =
240 talloc_get_type_abort(ev->additional_data,
241 struct select_event_context);
244 if (ev->signal_events &&
245 tevent_common_check_signal(ev)) {
249 if (ev->threaded_contexts != NULL) {
250 tevent_common_threaded_activate_immediate(ev);
253 if (ev->immediate_events &&
254 tevent_common_loop_immediate(ev)) {
258 tval = tevent_common_loop_timer_delay(ev);
259 if (tevent_timeval_is_zero(&tval)) {
263 return select_event_loop_select(select_ev, &tval);
266 static const struct tevent_ops select_event_ops = {
267 .context_init = select_event_context_init,
268 .add_fd = select_event_add_fd,
269 .set_fd_close_fn = tevent_common_fd_set_close_fn,
270 .get_fd_flags = tevent_common_fd_get_flags,
271 .set_fd_flags = tevent_common_fd_set_flags,
272 .add_timer = tevent_common_add_timer_v2,
273 .schedule_immediate = tevent_common_schedule_immediate,
274 .add_signal = tevent_common_add_signal,
275 .loop_once = select_event_loop_once,
276 .loop_wait = tevent_common_loop_wait,
279 _PRIVATE_ bool tevent_select_init(void)
281 return tevent_register_backend("select", &select_event_ops);