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
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12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
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21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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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>
49 #include <pthread_np.h>
58 #define MEV_DEL_PENDING 4
62 static pthread_t mevent_tid;
63 static int mevent_timid = 43;
64 static int mevent_pipefd[2];
65 static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
68 void (*me_func)(int, enum ev_type, void *);
69 #define me_msecs me_fd
77 LIST_ENTRY(mevent) me_list;
80 static LIST_HEAD(listhead, mevent) global_head, change_head;
85 pthread_mutex_lock(&mevent_lmutex);
91 pthread_mutex_unlock(&mevent_lmutex);
95 mevent_pipe_read(int fd, enum ev_type type, void *param)
101 * Drain the pipe read side. The fd is non-blocking so this is
105 status = read(fd, buf, sizeof(buf));
106 } while (status == MEVENT_MAX);
115 * If calling from outside the i/o thread, write a byte on the
116 * pipe to force the i/o thread to exit the blocking kevent call.
118 if (mevent_pipefd[1] != 0 && pthread_self() != mevent_tid) {
119 write(mevent_pipefd[1], &c, 1);
124 mevent_kq_filter(struct mevent *mevp)
130 if (mevp->me_type == EVF_READ)
131 retval = EVFILT_READ;
133 if (mevp->me_type == EVF_WRITE)
134 retval = EVFILT_WRITE;
136 if (mevp->me_type == EVF_TIMER)
137 retval = EVFILT_TIMER;
139 if (mevp->me_type == EVF_SIGNAL)
140 retval = EVFILT_SIGNAL;
146 mevent_kq_flags(struct mevent *mevp)
150 switch (mevp->me_state) {
152 ret = EV_ADD; /* implicitly enabled */
160 case MEV_DEL_PENDING:
172 mevent_kq_fflags(struct mevent *mevp)
174 /* XXX nothing yet, perhaps EV_EOF for reads ? */
179 mevent_build(int mfd, struct kevent *kev)
181 struct mevent *mevp, *tmpp;
188 LIST_FOREACH_SAFE(mevp, &change_head, me_list, tmpp) {
189 if (mevp->me_closefd) {
191 * A close of the file descriptor will remove the
196 if (mevp->me_type == EVF_TIMER) {
197 kev[i].ident = mevp->me_timid;
198 kev[i].data = mevp->me_msecs;
200 kev[i].ident = mevp->me_fd;
203 kev[i].filter = mevent_kq_filter(mevp);
204 kev[i].flags = mevent_kq_flags(mevp);
205 kev[i].fflags = mevent_kq_fflags(mevp);
211 LIST_REMOVE(mevp, me_list);
213 if (mevp->me_state == MEV_DEL_PENDING) {
216 LIST_INSERT_HEAD(&global_head, mevp, me_list);
219 assert(i < MEVENT_MAX);
228 mevent_handle(struct kevent *kev, int numev)
233 for (i = 0; i < numev; i++) {
236 /* XXX check for EV_ERROR ? */
238 (*mevp->me_func)(mevp->me_fd, mevp->me_type, mevp->me_param);
243 mevent_add(int tfd, enum ev_type type,
244 void (*func)(int, enum ev_type, void *), void *param)
246 struct mevent *lp, *mevp;
248 if (tfd < 0 || func == NULL) {
257 * Verify that the fd/type tuple is not present in any list
259 LIST_FOREACH(lp, &global_head, me_list) {
260 if (type != EVF_TIMER && lp->me_fd == tfd &&
261 lp->me_type == type) {
266 LIST_FOREACH(lp, &change_head, me_list) {
267 if (type != EVF_TIMER && lp->me_fd == tfd &&
268 lp->me_type == type) {
274 * Allocate an entry, populate it, and add it to the change list.
276 mevp = calloc(1, sizeof(struct mevent));
281 if (type == EVF_TIMER) {
282 mevp->me_msecs = tfd;
283 mevp->me_timid = mevent_timid++;
286 mevp->me_type = type;
287 mevp->me_func = func;
288 mevp->me_param = param;
290 LIST_INSERT_HEAD(&change_head, mevp, me_list);
292 mevp->me_state = MEV_ADD;
302 mevent_update(struct mevent *evp, int newstate)
305 * It's not possible to enable/disable a deleted event
307 if (evp->me_state == MEV_DEL_PENDING)
311 * No update needed if state isn't changing
313 if (evp->me_state == newstate)
318 evp->me_state = newstate;
321 * Place the entry onto the changed list if not already there.
323 if (evp->me_cq == 0) {
325 LIST_REMOVE(evp, me_list);
326 LIST_INSERT_HEAD(&change_head, evp, me_list);
336 mevent_enable(struct mevent *evp)
339 return (mevent_update(evp, MEV_ENABLE));
343 mevent_disable(struct mevent *evp)
346 return (mevent_update(evp, MEV_DISABLE));
350 mevent_delete_event(struct mevent *evp, int closefd)
355 * Place the entry onto the changed list if not already there, and
356 * mark as to be deleted.
358 if (evp->me_cq == 0) {
360 LIST_REMOVE(evp, me_list);
361 LIST_INSERT_HEAD(&change_head, evp, me_list);
364 evp->me_state = MEV_DEL_PENDING;
375 mevent_delete(struct mevent *evp)
378 return (mevent_delete_event(evp, 0));
382 mevent_delete_close(struct mevent *evp)
385 return (mevent_delete_event(evp, 1));
389 mevent_set_name(void)
392 pthread_set_name_np(mevent_tid, "mevent");
396 mevent_dispatch(void)
398 struct kevent changelist[MEVENT_MAX];
399 struct kevent eventlist[MEVENT_MAX];
400 struct mevent *pipev;
405 mevent_tid = pthread_self();
412 * Open the pipe that will be used for other threads to force
413 * the blocking kqueue call to exit by writing to it. Set the
414 * descriptor to non-blocking.
416 ret = pipe(mevent_pipefd);
423 * Add internal event handler for the pipe write fd
425 pipev = mevent_add(mevent_pipefd[0], EVF_READ, mevent_pipe_read, NULL);
426 assert(pipev != NULL);
430 * Build changelist if required.
431 * XXX the changelist can be put into the blocking call
432 * to eliminate the extra syscall. Currently better for
435 numev = mevent_build(mfd, changelist);
437 ret = kevent(mfd, changelist, numev, NULL, 0, NULL);
439 perror("Error return from kevent change");
444 * Block awaiting events
446 ret = kevent(mfd, NULL, 0, eventlist, MEVENT_MAX, NULL);
447 if (ret == -1 && errno != EINTR) {
448 perror("Error return from kevent monitor");
452 * Handle reported events
454 mevent_handle(eventlist, ret);