1 files changed, 249 insertions, 0 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
new file mode 100644
index 00000000000..fea03a3edaf
--- /dev/null
+++ b/tools/hv/hv_vss_daemon.c
@@ -0,0 +1,249 @@
+/*
+ * An implementation of the host initiated guest snapshot for Hyper-V.
+ *
+ *
+ * Copyright (C) 2013, Microsoft, Inc.
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ */
+
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+#include <sys/ioctl.h>
+#include <linux/types.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <mntent.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <arpa/inet.h>
+#include <linux/fs.h>
+#include <linux/connector.h>
+#include <linux/hyperv.h>
+#include <linux/netlink.h>
+#include <syslog.h>
+
+static char vss_recv_buffer[4096];
+static char vss_send_buffer[4096];
+static struct sockaddr_nl addr;
+
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
+
+static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
+{
+	int ret, fd = open(dir, O_RDONLY);
+
+	if (fd < 0)
+		return 1;
+	ret = ioctl(fd, cmd, 0);
+	syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
+	close(fd);
+	return !!ret;
+}
+
+static int vss_operate(int operation)
+{
+	char *fs_op;
+	char match[] = "/dev/";
+	FILE *mounts;
+	struct mntent *ent;
+	unsigned int cmd;
+	int error = 0, root_seen = 0;
+
+	switch (operation) {
+	case VSS_OP_FREEZE:
+		cmd = FIFREEZE;
+		fs_op = "freeze";
+		break;
+	case VSS_OP_THAW:
+		cmd = FITHAW;
+		fs_op = "thaw";
+		break;
+	default:
+		return -1;
+	}
+
+	mounts = setmntent("/proc/mounts", "r");
+	if (mounts == NULL)
+		return -1;
+
+	while ((ent = getmntent(mounts))) {
+		if (strncmp(ent->mnt_fsname, match, strlen(match)))
+			continue;
+		if (strcmp(ent->mnt_type, "iso9660") == 0)
+			continue;
+		if (strcmp(ent->mnt_dir, "/") == 0) {
+			root_seen = 1;
+			continue;
+		}
+		error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
+	}
+	endmntent(mounts);
+
+	if (root_seen) {
+		error |= vss_do_freeze("/", cmd, fs_op);
+	}
+
+	return error;
+}
+
+static int netlink_send(int fd, struct cn_msg *msg)
+{
+	struct nlmsghdr *nlh;
+	unsigned int size;
+	struct msghdr message;
+	char buffer[64];
+	struct iovec iov[2];
+
+	size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
+
+	nlh = (struct nlmsghdr *)buffer;
+	nlh->nlmsg_seq = 0;
+	nlh->nlmsg_pid = getpid();
+	nlh->nlmsg_type = NLMSG_DONE;
+	nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
+	nlh->nlmsg_flags = 0;
+
+	iov[0].iov_base = nlh;
+	iov[0].iov_len = sizeof(*nlh);
+
+	iov[1].iov_base = msg;
+	iov[1].iov_len = size;
+
+	memset(&message, 0, sizeof(message));
+	message.msg_name = &addr;
+	message.msg_namelen = sizeof(addr);
+	message.msg_iov = iov;
+	message.msg_iovlen = 2;
+
+	return sendmsg(fd, &message, 0);
+}
+
+int main(void)
+{
+	int fd, len, nl_group;
+	int error;
+	struct cn_msg *message;
+	struct pollfd pfd;
+	struct nlmsghdr *incoming_msg;
+	struct cn_msg	*incoming_cn_msg;
+	int	op;
+	struct hv_vss_msg *vss_msg;
+
+	if (daemon(1, 0))
+		return 1;
+
+	openlog("Hyper-V VSS", 0, LOG_USER);
+	syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
+
+	fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+	if (fd < 0) {
+		syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd);
+		exit(EXIT_FAILURE);
+	}
+	addr.nl_family = AF_NETLINK;
+	addr.nl_pad = 0;
+	addr.nl_pid = 0;
+	addr.nl_groups = 0;
+
+
+	error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+	if (error < 0) {
+		syslog(LOG_ERR, "bind failed; error:%d", error);
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+	nl_group = CN_VSS_IDX;
+	setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group));
+	/*
+	 * Register ourselves with the kernel.
+	 */
+	message = (struct cn_msg *)vss_send_buffer;
+	message->id.idx = CN_VSS_IDX;
+	message->id.val = CN_VSS_VAL;
+	message->ack = 0;
+	vss_msg = (struct hv_vss_msg *)message->data;
+	vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
+
+	message->len = sizeof(struct hv_vss_msg);
+
+	len = netlink_send(fd, message);
+	if (len < 0) {
+		syslog(LOG_ERR, "netlink_send failed; error:%d", len);
+		close(fd);
+		exit(EXIT_FAILURE);
+	}
+
+	pfd.fd = fd;
+
+	while (1) {
+		struct sockaddr *addr_p = (struct sockaddr *) &addr;
+		socklen_t addr_l = sizeof(addr);
+		pfd.events = POLLIN;
+		pfd.revents = 0;
+		poll(&pfd, 1, -1);
+
+		len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0,
+				addr_p, &addr_l);
+
+		if (len < 0) {
+			syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
+					addr.nl_pid, errno, strerror(errno));
+			close(fd);
+			return -1;
+		}
+
+		if (addr.nl_pid) {
+			syslog(LOG_WARNING,
+				"Received packet from untrusted pid:%u",
+				addr.nl_pid);
+			continue;
+		}
+
+		incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
+
+		if (incoming_msg->nlmsg_type != NLMSG_DONE)
+			continue;
+
+		incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
+		vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
+		op = vss_msg->vss_hdr.operation;
+		error =  HV_S_OK;
+
+		switch (op) {
+		case VSS_OP_FREEZE:
+		case VSS_OP_THAW:
+			error = vss_operate(op);
+			if (error)
+				error = HV_E_FAIL;
+			break;
+		default:
+			syslog(LOG_ERR, "Illegal op:%d\n", op);
+		}
+		vss_msg->error = error;
+		len = netlink_send(fd, incoming_cn_msg);
+		if (len < 0) {
+			syslog(LOG_ERR, "net_link send failed; error:%d", len);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+}