/*- * Copyright (c) 2011 NetApp, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ /* * Micro event library for FreeBSD, designed for a single i/o thread * using kqueue, and having events be persistent by default. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include "mevent.h" #define MEVENT_MAX 64 #define MEV_ADD 1 #define MEV_ENABLE 2 #define MEV_DISABLE 3 #define MEV_DEL_PENDING 4 extern char *vmname; static pthread_t mevent_tid; static int mevent_timid = 43; static int mevent_pipefd[2]; static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER; struct mevent { void (*me_func)(int, enum ev_type, void *); #define me_msecs me_fd int me_fd; int me_timid; enum ev_type me_type; void *me_param; int me_cq; int me_state; int me_closefd; LIST_ENTRY(mevent) me_list; }; static LIST_HEAD(listhead, mevent) global_head, change_head; static void mevent_qlock(void) { pthread_mutex_lock(&mevent_lmutex); } static void mevent_qunlock(void) { pthread_mutex_unlock(&mevent_lmutex); } static void mevent_pipe_read(int fd, enum ev_type type, void *param) { char buf[MEVENT_MAX]; int status; /* * Drain the pipe read side. The fd is non-blocking so this is * safe to do. */ do { status = read(fd, buf, sizeof(buf)); } while (status == MEVENT_MAX); } static void mevent_notify(void) { char c; /* * If calling from outside the i/o thread, write a byte on the * pipe to force the i/o thread to exit the blocking kevent call. */ if (mevent_pipefd[1] != 0 && pthread_self() != mevent_tid) { write(mevent_pipefd[1], &c, 1); } } static int mevent_kq_filter(struct mevent *mevp) { int retval; retval = 0; if (mevp->me_type == EVF_READ) retval = EVFILT_READ; if (mevp->me_type == EVF_WRITE) retval = EVFILT_WRITE; if (mevp->me_type == EVF_TIMER) retval = EVFILT_TIMER; if (mevp->me_type == EVF_SIGNAL) retval = EVFILT_SIGNAL; return (retval); } static int mevent_kq_flags(struct mevent *mevp) { int ret; switch (mevp->me_state) { case MEV_ADD: ret = EV_ADD; /* implicitly enabled */ break; case MEV_ENABLE: ret = EV_ENABLE; break; case MEV_DISABLE: ret = EV_DISABLE; break; case MEV_DEL_PENDING: ret = EV_DELETE; break; default: assert(0); break; } return (ret); } static int mevent_kq_fflags(struct mevent *mevp) { /* XXX nothing yet, perhaps EV_EOF for reads ? */ return (0); } static int mevent_build(int mfd, struct kevent *kev) { struct mevent *mevp, *tmpp; int i; i = 0; mevent_qlock(); LIST_FOREACH_SAFE(mevp, &change_head, me_list, tmpp) { if (mevp->me_closefd) { /* * A close of the file descriptor will remove the * event */ close(mevp->me_fd); } else { if (mevp->me_type == EVF_TIMER) { kev[i].ident = mevp->me_timid; kev[i].data = mevp->me_msecs; } else { kev[i].ident = mevp->me_fd; kev[i].data = 0; } kev[i].filter = mevent_kq_filter(mevp); kev[i].flags = mevent_kq_flags(mevp); kev[i].fflags = mevent_kq_fflags(mevp); kev[i].udata = mevp; i++; } mevp->me_cq = 0; LIST_REMOVE(mevp, me_list); if (mevp->me_state == MEV_DEL_PENDING) { free(mevp); } else { LIST_INSERT_HEAD(&global_head, mevp, me_list); } assert(i < MEVENT_MAX); } mevent_qunlock(); return (i); } static void mevent_handle(struct kevent *kev, int numev) { struct mevent *mevp; int i; for (i = 0; i < numev; i++) { mevp = kev[i].udata; /* XXX check for EV_ERROR ? */ (*mevp->me_func)(mevp->me_fd, mevp->me_type, mevp->me_param); } } struct mevent * mevent_add(int tfd, enum ev_type type, void (*func)(int, enum ev_type, void *), void *param) { struct mevent *lp, *mevp; if (tfd < 0 || func == NULL) { return (NULL); } mevp = NULL; mevent_qlock(); /* * Verify that the fd/type tuple is not present in any list */ LIST_FOREACH(lp, &global_head, me_list) { if (type != EVF_TIMER && lp->me_fd == tfd && lp->me_type == type) { goto exit; } } LIST_FOREACH(lp, &change_head, me_list) { if (type != EVF_TIMER && lp->me_fd == tfd && lp->me_type == type) { goto exit; } } /* * Allocate an entry, populate it, and add it to the change list. */ mevp = calloc(1, sizeof(struct mevent)); if (mevp == NULL) { goto exit; } if (type == EVF_TIMER) { mevp->me_msecs = tfd; mevp->me_timid = mevent_timid++; } else mevp->me_fd = tfd; mevp->me_type = type; mevp->me_func = func; mevp->me_param = param; LIST_INSERT_HEAD(&change_head, mevp, me_list); mevp->me_cq = 1; mevp->me_state = MEV_ADD; mevent_notify(); exit: mevent_qunlock(); return (mevp); } static int mevent_update(struct mevent *evp, int newstate) { /* * It's not possible to enable/disable a deleted event */ if (evp->me_state == MEV_DEL_PENDING) return (EINVAL); /* * No update needed if state isn't changing */ if (evp->me_state == newstate) return (0); mevent_qlock(); evp->me_state = newstate; /* * Place the entry onto the changed list if not already there. */ if (evp->me_cq == 0) { evp->me_cq = 1; LIST_REMOVE(evp, me_list); LIST_INSERT_HEAD(&change_head, evp, me_list); mevent_notify(); } mevent_qunlock(); return (0); } int mevent_enable(struct mevent *evp) { return (mevent_update(evp, MEV_ENABLE)); } int mevent_disable(struct mevent *evp) { return (mevent_update(evp, MEV_DISABLE)); } static int mevent_delete_event(struct mevent *evp, int closefd) { mevent_qlock(); /* * Place the entry onto the changed list if not already there, and * mark as to be deleted. */ if (evp->me_cq == 0) { evp->me_cq = 1; LIST_REMOVE(evp, me_list); LIST_INSERT_HEAD(&change_head, evp, me_list); mevent_notify(); } evp->me_state = MEV_DEL_PENDING; if (closefd) evp->me_closefd = 1; mevent_qunlock(); return (0); } int mevent_delete(struct mevent *evp) { return (mevent_delete_event(evp, 0)); } int mevent_delete_close(struct mevent *evp) { return (mevent_delete_event(evp, 1)); } static void mevent_set_name(void) { pthread_set_name_np(mevent_tid, "mevent"); } void mevent_dispatch(void) { struct kevent changelist[MEVENT_MAX]; struct kevent eventlist[MEVENT_MAX]; struct mevent *pipev; int mfd; int numev; int ret; mevent_tid = pthread_self(); mevent_set_name(); mfd = kqueue(); assert(mfd > 0); /* * Open the pipe that will be used for other threads to force * the blocking kqueue call to exit by writing to it. Set the * descriptor to non-blocking. */ ret = pipe(mevent_pipefd); if (ret < 0) { perror("pipe"); exit(0); } /* * Add internal event handler for the pipe write fd */ pipev = mevent_add(mevent_pipefd[0], EVF_READ, mevent_pipe_read, NULL); assert(pipev != NULL); for (;;) { /* * Build changelist if required. * XXX the changelist can be put into the blocking call * to eliminate the extra syscall. Currently better for * debug. */ numev = mevent_build(mfd, changelist); if (numev) { ret = kevent(mfd, changelist, numev, NULL, 0, NULL); if (ret == -1) { perror("Error return from kevent change"); } } /* * Block awaiting events */ ret = kevent(mfd, NULL, 0, eventlist, MEVENT_MAX, NULL); if (ret == -1 && errno != EINTR) { perror("Error return from kevent monitor"); } /* * Handle reported events */ mevent_handle(eventlist, ret); } }