2 * Copyright (c) 2011 NetApp, Inc.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * Micro event library for FreeBSD, designed for a single i/o thread
31 * using kqueue, and having events be persistent by default.
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
44 #include <sys/types.h>
45 #include <sys/event.h>
56 #define MEV_DEL_PENDING 3
58 static pthread_t mevent_tid;
59 static int mevent_pipefd[2];
60 static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
63 void (*me_func)(int, enum ev_type, void *);
70 LIST_ENTRY(mevent) me_list;
73 static LIST_HEAD(listhead, mevent) global_head, change_head;
78 pthread_mutex_lock(&mevent_lmutex);
84 pthread_mutex_unlock(&mevent_lmutex);
88 mevent_pipe_read(int fd, enum ev_type type, void *param)
94 * Drain the pipe read side. The fd is non-blocking so this is
98 status = read(fd, buf, sizeof(buf));
99 } while (status == MEVENT_MAX);
108 * If calling from outside the i/o thread, write a byte on the
109 * pipe to force the i/o thread to exit the blocking kevent call.
111 if (mevent_pipefd[1] != 0 && pthread_self() != mevent_tid) {
112 write(mevent_pipefd[1], &c, 1);
117 mevent_kq_filter(struct mevent *mevp)
123 if (mevp->me_type == EVF_READ)
124 retval = EVFILT_READ;
126 if (mevp->me_type == EVF_WRITE)
127 retval = EVFILT_WRITE;
133 mevent_kq_flags(struct mevent *mevp)
137 switch (mevp->me_state) {
144 case MEV_DEL_PENDING:
153 mevent_kq_fflags(struct mevent *mevp)
155 /* XXX nothing yet, perhaps EV_EOF for reads ? */
160 mevent_build(int mfd, struct kevent *kev)
162 struct mevent *mevp, *tmpp;
169 LIST_FOREACH_SAFE(mevp, &change_head, me_list, tmpp) {
170 if (mevp->me_closefd) {
172 * A close of the file descriptor will remove the
177 kev[i].ident = mevp->me_fd;
178 kev[i].filter = mevent_kq_filter(mevp);
179 kev[i].flags = mevent_kq_flags(mevp);
180 kev[i].fflags = mevent_kq_fflags(mevp);
187 LIST_REMOVE(mevp, me_list);
189 if (mevp->me_state == MEV_DEL_PENDING) {
192 LIST_INSERT_HEAD(&global_head, mevp, me_list);
195 assert(i < MEVENT_MAX);
204 mevent_handle(struct kevent *kev, int numev)
209 for (i = 0; i < numev; i++) {
212 /* XXX check for EV_ERROR ? */
214 (*mevp->me_func)(mevp->me_fd, mevp->me_type, mevp->me_param);
219 mevent_add(int fd, enum ev_type type,
220 void (*func)(int, enum ev_type, void *), void *param)
222 struct mevent *lp, *mevp;
224 if (fd < 0 || func == NULL) {
233 * Verify that the fd/type tuple is not present in any list
235 LIST_FOREACH(lp, &global_head, me_list) {
236 if (lp->me_fd == fd && lp->me_type == type) {
241 LIST_FOREACH(lp, &change_head, me_list) {
242 if (lp->me_fd == fd && lp->me_type == type) {
248 * Allocate an entry, populate it, and add it to the change list.
250 mevp = malloc(sizeof(struct mevent));
255 memset(mevp, 0, sizeof(struct mevent));
257 mevp->me_type = type;
258 mevp->me_func = func;
259 mevp->me_param = param;
261 LIST_INSERT_HEAD(&change_head, mevp, me_list);
263 mevp->me_state = MEV_ENABLE;
273 mevent_update(struct mevent *evp, int newstate)
276 * It's not possible to enable/disable a deleted event
278 if (evp->me_state == MEV_DEL_PENDING)
282 * No update needed if state isn't changing
284 if (evp->me_state == newstate)
289 evp->me_state = newstate;
292 * Place the entry onto the changed list if not already there.
294 if (evp->me_cq == 0) {
296 LIST_REMOVE(evp, me_list);
297 LIST_INSERT_HEAD(&change_head, evp, me_list);
307 mevent_enable(struct mevent *evp)
310 return (mevent_update(evp, MEV_ENABLE));
314 mevent_disable(struct mevent *evp)
317 return (mevent_update(evp, MEV_DISABLE));
321 mevent_delete_event(struct mevent *evp, int closefd)
326 * Place the entry onto the changed list if not already there, and
327 * mark as to be deleted.
329 if (evp->me_cq == 0) {
331 LIST_REMOVE(evp, me_list);
332 LIST_INSERT_HEAD(&change_head, evp, me_list);
335 evp->me_state = MEV_DEL_PENDING;
346 mevent_delete(struct mevent *evp)
349 return (mevent_delete_event(evp, 0));
353 mevent_delete_close(struct mevent *evp)
356 return (mevent_delete_event(evp, 1));
360 mevent_dispatch(void)
362 struct kevent changelist[MEVENT_MAX];
363 struct kevent eventlist[MEVENT_MAX];
364 struct mevent *pipev;
369 mevent_tid = pthread_self();
375 * Open the pipe that will be used for other threads to force
376 * the blocking kqueue call to exit by writing to it. Set the
377 * descriptor to non-blocking.
379 ret = pipe(mevent_pipefd);
386 * Add internal event handler for the pipe write fd
388 pipev = mevent_add(mevent_pipefd[0], EVF_READ, mevent_pipe_read, NULL);
389 assert(pipev != NULL);
393 * Build changelist if required.
394 * XXX the changelist can be put into the blocking call
395 * to eliminate the extra syscall. Currently better for
398 numev = mevent_build(mfd, changelist);
400 ret = kevent(mfd, changelist, numev, NULL, 0, NULL);
402 perror("Error return from kevent change");
407 * Block awaiting events
409 ret = kevent(mfd, NULL, 0, eventlist, MEVENT_MAX, NULL);
411 perror("Error return from kevent monitor");
415 * Handle reported events
417 mevent_handle(eventlist, ret);