1 files changed, 432 insertions, 0 deletions
diff --git a/usr.sbin/bhyve/mevent.c b/usr.sbin/bhyve/mevent.c
new file mode 100644
index 0000000..a6109db
--- /dev/null
+++ b/usr.sbin/bhyve/mevent.c
@@ -0,0 +1,432 @@
+/*-
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+
+#include <pthread.h>
+#include <pthread_np.h>
+
+#include "mevent.h"
+
+#define	MEVENT_MAX	64
+
+#define MEV_ENABLE	1
+#define MEV_DISABLE	2
+#define MEV_DEL_PENDING	3
+
+extern char *vmname;
+
+static pthread_t mevent_tid;
+static int mevent_pipefd[2];
+static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
+
+struct mevent {	
+	void	(*me_func)(int, enum ev_type, void *);
+	int	me_fd;
+	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;
+
+	return (retval);
+}
+
+static int
+mevent_kq_flags(struct mevent *mevp)
+{
+	int ret;
+
+	switch (mevp->me_state) {
+	case MEV_ENABLE:
+		ret = EV_ADD;
+		break;
+	case MEV_DISABLE:
+		ret = EV_DISABLE;
+		break;
+	case MEV_DEL_PENDING:
+		ret = EV_DELETE;
+		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 {
+			kev[i].ident = mevp->me_fd;
+			kev[i].filter = mevent_kq_filter(mevp);
+			kev[i].flags = mevent_kq_flags(mevp);
+			kev[i].fflags = mevent_kq_fflags(mevp);
+			kev[i].data = 0;
+			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 fd, enum ev_type type,
+	   void (*func)(int, enum ev_type, void *), void *param)
+{
+	struct mevent *lp, *mevp;
+
+	if (fd < 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 (lp->me_fd == fd && lp->me_type == type) {
+			goto exit;
+		}
+	}
+
+	LIST_FOREACH(lp, &change_head, me_list) {
+		if (lp->me_fd == fd && lp->me_type == type) {
+			goto exit;
+		}
+	}
+
+	/*
+	 * Allocate an entry, populate it, and add it to the change list.
+	 */
+	mevp = malloc(sizeof(struct mevent));
+	if (mevp == NULL) {
+		goto exit;
+	}
+
+	memset(mevp, 0, sizeof(struct mevent));
+	mevp->me_fd = fd;
+	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_ENABLE;
+	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)
+{
+	char tname[MAXCOMLEN + 1];
+
+	snprintf(tname, sizeof(tname), "%s mevent", vmname);
+	pthread_set_name_np(mevent_tid, tname);
+}
+
+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) {
+			perror("Error return from kevent monitor");
+		}
+		
+		/*
+		 * Handle reported events
+		 */
+		mevent_handle(eventlist, ret);
+	}			
+}