2 * An implementation of the host initiated guest snapshot for Hyper-V.
5 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15 * NON INFRINGEMENT. See the GNU General Public License for more
21 #include <sys/types.h>
22 #include <sys/socket.h>
24 #include <sys/ioctl.h>
25 #include <linux/types.h>
34 #include <arpa/inet.h>
36 #include <linux/connector.h>
37 #include <linux/hyperv.h>
38 #include <linux/netlink.h>
41 static char vss_recv_buffer[4096];
42 static char vss_send_buffer[4096];
43 static struct sockaddr_nl addr;
46 #define SOL_NETLINK 270
50 static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
52 int ret, fd = open(dir, O_RDONLY);
56 ret = ioctl(fd, cmd, 0);
57 syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
62 static int vss_operate(int operation)
65 char match[] = "/dev/";
69 int error = 0, root_seen = 0;
84 mounts = setmntent("/proc/mounts", "r");
88 while ((ent = getmntent(mounts))) {
89 if (strncmp(ent->mnt_fsname, match, strlen(match)))
91 if (strcmp(ent->mnt_type, "iso9660") == 0)
93 if (strcmp(ent->mnt_dir, "/") == 0) {
97 error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
102 error |= vss_do_freeze("/", cmd, fs_op);
108 static int netlink_send(int fd, struct cn_msg *msg)
110 struct nlmsghdr *nlh;
112 struct msghdr message;
116 size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
118 nlh = (struct nlmsghdr *)buffer;
120 nlh->nlmsg_pid = getpid();
121 nlh->nlmsg_type = NLMSG_DONE;
122 nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
123 nlh->nlmsg_flags = 0;
125 iov[0].iov_base = nlh;
126 iov[0].iov_len = sizeof(*nlh);
128 iov[1].iov_base = msg;
129 iov[1].iov_len = size;
131 memset(&message, 0, sizeof(message));
132 message.msg_name = &addr;
133 message.msg_namelen = sizeof(addr);
134 message.msg_iov = iov;
135 message.msg_iovlen = 2;
137 return sendmsg(fd, &message, 0);
142 int fd, len, nl_group;
144 struct cn_msg *message;
146 struct nlmsghdr *incoming_msg;
147 struct cn_msg *incoming_cn_msg;
149 struct hv_vss_msg *vss_msg;
154 openlog("Hyper-V VSS", 0, LOG_USER);
155 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
157 fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
159 syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd);
162 addr.nl_family = AF_NETLINK;
168 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
170 syslog(LOG_ERR, "bind failed; error:%d", error);
174 nl_group = CN_VSS_IDX;
175 setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group));
177 * Register ourselves with the kernel.
179 message = (struct cn_msg *)vss_send_buffer;
180 message->id.idx = CN_VSS_IDX;
181 message->id.val = CN_VSS_VAL;
183 vss_msg = (struct hv_vss_msg *)message->data;
184 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
186 message->len = sizeof(struct hv_vss_msg);
188 len = netlink_send(fd, message);
190 syslog(LOG_ERR, "netlink_send failed; error:%d", len);
198 struct sockaddr *addr_p = (struct sockaddr *) &addr;
199 socklen_t addr_l = sizeof(addr);
204 len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0,
208 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
209 addr.nl_pid, errno, strerror(errno));
216 "Received packet from untrusted pid:%u",
221 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
223 if (incoming_msg->nlmsg_type != NLMSG_DONE)
226 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
227 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
228 op = vss_msg->vss_hdr.operation;
234 error = vss_operate(op);
239 syslog(LOG_ERR, "Illegal op:%d\n", op);
241 vss_msg->error = error;
242 len = netlink_send(fd, incoming_cn_msg);
244 syslog(LOG_ERR, "net_link send failed; error:%d", len);