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 struct sockaddr_nl addr;
44 #define SOL_NETLINK 270
48 static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
50 int ret, fd = open(dir, O_RDONLY);
54 ret = ioctl(fd, cmd, 0);
55 syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
60 static int vss_operate(int operation)
63 char match[] = "/dev/";
67 int error = 0, root_seen = 0;
82 mounts = setmntent("/proc/mounts", "r");
86 while ((ent = getmntent(mounts))) {
87 if (strncmp(ent->mnt_fsname, match, strlen(match)))
89 if (strcmp(ent->mnt_type, "iso9660") == 0)
91 if (strcmp(ent->mnt_dir, "/") == 0) {
95 error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
100 error |= vss_do_freeze("/", cmd, fs_op);
106 static int netlink_send(int fd, struct cn_msg *msg)
108 struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE };
110 struct msghdr message;
113 size = sizeof(struct cn_msg) + msg->len;
115 nlh.nlmsg_pid = getpid();
116 nlh.nlmsg_len = NLMSG_LENGTH(size);
118 iov[0].iov_base = &nlh;
119 iov[0].iov_len = sizeof(nlh);
121 iov[1].iov_base = msg;
122 iov[1].iov_len = size;
124 memset(&message, 0, sizeof(message));
125 message.msg_name = &addr;
126 message.msg_namelen = sizeof(addr);
127 message.msg_iov = iov;
128 message.msg_iovlen = 2;
130 return sendmsg(fd, &message, 0);
135 int fd, len, nl_group;
137 struct cn_msg *message;
139 struct nlmsghdr *incoming_msg;
140 struct cn_msg *incoming_cn_msg;
142 struct hv_vss_msg *vss_msg;
143 char *vss_send_buffer;
144 char *vss_recv_buffer;
145 size_t vss_recv_buffer_len;
150 openlog("Hyper-V VSS", 0, LOG_USER);
151 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
153 vss_recv_buffer_len = NLMSG_HDRLEN + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg);
154 vss_send_buffer = calloc(1, vss_recv_buffer_len);
155 vss_recv_buffer = calloc(1, vss_recv_buffer_len);
156 if (!(vss_send_buffer && vss_recv_buffer)) {
157 syslog(LOG_ERR, "Failed to allocate netlink buffers");
161 fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
163 syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
164 errno, strerror(errno));
167 addr.nl_family = AF_NETLINK;
173 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
175 syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno));
179 nl_group = CN_VSS_IDX;
180 if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
181 syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
186 * Register ourselves with the kernel.
188 message = (struct cn_msg *)vss_send_buffer;
189 message->id.idx = CN_VSS_IDX;
190 message->id.val = CN_VSS_VAL;
192 vss_msg = (struct hv_vss_msg *)message->data;
193 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
195 message->len = sizeof(struct hv_vss_msg);
197 len = netlink_send(fd, message);
199 syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
207 struct sockaddr *addr_p = (struct sockaddr *) &addr;
208 socklen_t addr_l = sizeof(addr);
212 if (poll(&pfd, 1, -1) < 0) {
213 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
214 if (errno == EINVAL) {
222 len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0,
226 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
227 addr.nl_pid, errno, strerror(errno));
234 "Received packet from untrusted pid:%u",
239 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
241 if (incoming_msg->nlmsg_type != NLMSG_DONE)
244 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
245 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
246 op = vss_msg->vss_hdr.operation;
252 error = vss_operate(op);
257 syslog(LOG_ERR, "Illegal op:%d\n", op);
259 vss_msg->error = error;
260 len = netlink_send(fd, incoming_cn_msg);
262 syslog(LOG_ERR, "net_link send failed; error:%d %s",
263 errno, strerror(errno));