[PATCH v2 08/11] lib/librte_vhost: add select based event driven processing

[Huawei Xie <huawei.xie-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

for more generic event driven processing, refer to:
	http://libevent.org/


Signed-off-by: Huawei Xie <huawei.xie-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
 lib/librte_vhost/vhost_user/fd_man.c | 207 +++++++++++++++++++++++++++++++++++
 lib/librte_vhost/vhost_user/fd_man.h |  64 +++++++++++
 2 files changed, 271 insertions(+)
 create mode 100644 lib/librte_vhost/vhost_user/fd_man.c
 create mode 100644 lib/librte_vhost/vhost_user/fd_man.h

diff --git a/lib/librte_vhost/vhost_user/fd_man.c b/lib/librte_vhost/vhost_user/fd_man.c
new file mode 100644
index 0000000..929fbc3
--- /dev/null
+++ b/lib/librte_vhost/vhost_user/fd_man.c
@@ -0,0 +1,207 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "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 THE COPYRIGHT
+ *   OWNER 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.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <rte_log.h>
+
+#include "fd_man.h"
+
+/**
+ * Returns the index in the fdset for a given fd.
+ * If fd is -1, it means to search for a free entry.
+ * @return
+ *   index for the fd, or -1 if fd isn't in the fdset.
+ */
+static int
+fdset_find_fd(struct fdset *pfdset, int fd)
+{
+	int i;
+
+	if (pfdset == NULL)
+		return -1;
+
+	for (i = 0; i < MAX_FDS && pfdset->fd[i].fd != fd; i++)
+		;
+
+	return i ==  MAX_FDS ? -1 : i;
+}
+
+static int
+fdset_find_free_slot(struct fdset *pfdset)
+{
+	return fdset_find_fd(pfdset, -1);
+}
+
+static void
+fdset_add_fd(struct fdset  *pfdset, int idx, int fd,
+	fd_cb rcb, fd_cb wcb, void *dat)
+{
+	struct fdentry *pfdentry;
+
+	if (pfdset == NULL || idx >= MAX_FDS)
+		return;
+
+	pfdentry = &pfdset->fd[idx];
+	pfdentry->fd = fd;
+	pfdentry->rcb = rcb;
+	pfdentry->wcb = wcb;
+	pfdentry->dat = dat;
+}
+
+/**
+ * Fill the read/write fd_set with the fds in the fdset.
+ * @return
+ *  the maximum fds filled in the read/write fd_set.
+ */
+static int
+fdset_fill(fd_set *rfset, fd_set *wfset, struct fdset *pfdset)
+{
+	struct fdentry *pfdentry;
+	int i, maxfds = -1;
+	int num = MAX_FDS;
+
+	if (pfdset == NULL)
+		return -1;
+
+	for (i = 0; i < num; i++) {
+		pfdentry = &pfdset->fd[i];
+		if (pfdentry->fd != -1) {
+			int added = 0;
+			if (pfdentry->rcb && rfset) {
+				FD_SET(pfdentry->fd, rfset);
+				added = 1;
+			}
+			if (pfdentry->wcb && wfset) {
+				FD_SET(pfdentry->fd, wfset);
+				added = 1;
+			}
+			if (added)
+				maxfds = pfdentry->fd < maxfds ?
+					maxfds : pfdentry->fd;
+		}
+	}
+	return maxfds;
+}
+
+void
+fdset_init(struct fdset *pfdset)
+{
+	int i;
+
+	if (pfdset == NULL)
+		return;
+
+	for (i = 0; i < MAX_FDS; i++)
+		pfdset->fd[i].fd = -1;
+	pfdset->num = 0;
+}
+
+/**
+ * Register the fd in the fdset with read/write handler and context.
+ */
+int
+fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat)
+{
+	int i;
+
+	if (pfdset == NULL || fd == -1)
+		return -1;
+
+	/* Find a free slot in the list. */
+	i = fdset_find_free_slot(pfdset);
+	if (i == -1)
+		return -2;
+
+	fdset_add_fd(pfdset, i, fd, rcb, wcb, dat);
+	pfdset->num++;
+
+	return 0;
+}
+
+/**
+ *  Unregister the fd from the fdset.
+ */
+void
+fdset_del(struct fdset *pfdset, int fd)
+{
+	int i;
+
+	i = fdset_find_fd(pfdset, fd);
+	if (i != -1 && fd != -1) {
+		pfdset->fd[i].fd = -1;
+		pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL;
+		pfdset->num--;
+	}
+}
+
+/**
+ * This functions runs in infinite blocking loop until there is no fd in
+ * pfdset. It calls corresponding r/w handler if there is event on the fd.
+ */
+void
+fdset_event_dispatch(struct fdset *pfdset)
+{
+	fd_set rfds, wfds;
+	int i, maxfds;
+	struct fdentry *pfdentry;
+	int num = MAX_FDS;
+
+	if (pfdset == NULL)
+		return;
+
+	while (1) {
+		FD_ZERO(&rfds);
+		FD_ZERO(&wfds);
+		maxfds = fdset_fill(&rfds, &wfds, pfdset);
+		if (maxfds == -1)
+			return;
+
+		select(maxfds + 1, &rfds, &wfds, NULL, NULL);
+
+		for (i = 0; i < num; i++) {
+			pfdentry = &pfdset->fd[i];
+			if (pfdentry->fd >= 0 && FD_ISSET(pfdentry->fd, &rfds) && pfdentry->rcb)
+				pfdentry->rcb(pfdentry->fd, pfdentry->dat);
+			if (pfdentry->fd >= 0 && FD_ISSET(pfdentry->fd, &wfds) && pfdentry->wcb)
+				pfdentry->wcb(pfdentry->fd, pfdentry->dat);
+		}
+	}
+}
diff --git a/lib/librte_vhost/vhost_user/fd_man.h b/lib/librte_vhost/vhost_user/fd_man.h
new file mode 100644
index 0000000..26b4619
--- /dev/null
+++ b/lib/librte_vhost/vhost_user/fd_man.h
@@ -0,0 +1,64 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "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 THE COPYRIGHT
+ *   OWNER 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.
+ */
+
+#ifndef _FD_MAN_H_
+#define _FD_MAN_H_
+#include <stdint.h>
+
+#define MAX_FDS 1024
+
+typedef void (*fd_cb)(int fd, void *dat);
+
+struct fdentry {
+	int fd;		/* -1 indicates this entry is empty */
+	fd_cb rcb;	/* callback when this fd is readable. */
+	fd_cb wcb;	/* callback when this fd is writeable.*/
+	void *dat;	/* fd context */
+};
+
+struct fdset {
+	struct fdentry fd[MAX_FDS];
+	int num;	/* current fd number of this fdset */
+};
+
+
+void fdset_init(struct fdset *pfdset);
+
+int fdset_add(struct fdset *pfdset, int fd,
+	fd_cb rcb, fd_cb wcb, void *dat);
+
+void fdset_del(struct fdset *pfdset, int fd);
+
+void fdset_event_dispatch(struct fdset *pfdset);
+
+#endif
-- 
1.8.1.4