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>
33 #include <arpa/inet.h>
35 #include <linux/connector.h>
36 #include <linux/hyperv.h>
37 #include <linux/netlink.h>
40 static struct sockaddr_nl addr;
43 #define SOL_NETLINK 270
47 static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op)
49 int ret, fd = open(dir, O_RDONLY);
53 ret = ioctl(fd, cmd, 0);
54 syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
59 static int vss_operate(int operation)
62 char match[] = "/dev/";
66 int error = 0, root_seen = 0;
81 mounts = setmntent("/proc/mounts", "r");
85 while ((ent = getmntent(mounts))) {
86 if (strncmp(ent->mnt_fsname, match, strlen(match)))
88 if (strcmp(ent->mnt_type, "iso9660") == 0)
90 if (strcmp(ent->mnt_type, "vfat") == 0)
92 if (strcmp(ent->mnt_dir, "/") == 0) {
96 error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
101 error |= vss_do_freeze("/", cmd, fs_op);
107 static int netlink_send(int fd, struct cn_msg *msg)
109 struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE };
111 struct msghdr message;
114 size = sizeof(struct cn_msg) + msg->len;
116 nlh.nlmsg_pid = getpid();
117 nlh.nlmsg_len = NLMSG_LENGTH(size);
119 iov[0].iov_base = &nlh;
120 iov[0].iov_len = sizeof(nlh);
122 iov[1].iov_base = msg;
123 iov[1].iov_len = size;
125 memset(&message, 0, sizeof(message));
126 message.msg_name = &addr;
127 message.msg_namelen = sizeof(addr);
128 message.msg_iov = iov;
129 message.msg_iovlen = 2;
131 return sendmsg(fd, &message, 0);
136 int fd, len, nl_group;
138 struct cn_msg *message;
140 struct nlmsghdr *incoming_msg;
141 struct cn_msg *incoming_cn_msg;
143 struct hv_vss_msg *vss_msg;
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_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg);
154 vss_recv_buffer = calloc(1, vss_recv_buffer_len);
155 if (!vss_recv_buffer) {
156 syslog(LOG_ERR, "Failed to allocate netlink buffers");
160 fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
162 syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
163 errno, strerror(errno));
166 addr.nl_family = AF_NETLINK;
172 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
174 syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno));
178 nl_group = CN_VSS_IDX;
179 if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
180 syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
185 * Register ourselves with the kernel.
187 message = (struct cn_msg *)vss_recv_buffer;
188 message->id.idx = CN_VSS_IDX;
189 message->id.val = CN_VSS_VAL;
191 vss_msg = (struct hv_vss_msg *)message->data;
192 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
194 message->len = sizeof(struct hv_vss_msg);
196 len = netlink_send(fd, message);
198 syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
206 struct sockaddr *addr_p = (struct sockaddr *) &addr;
207 socklen_t addr_l = sizeof(addr);
211 if (poll(&pfd, 1, -1) < 0) {
212 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
213 if (errno == EINVAL) {
221 len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0,
225 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
226 addr.nl_pid, errno, strerror(errno));
233 "Received packet from untrusted pid:%u",
238 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
240 if (incoming_msg->nlmsg_type != NLMSG_DONE)
243 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
244 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
245 op = vss_msg->vss_hdr.operation;
251 error = vss_operate(op);
256 syslog(LOG_ERR, "Illegal op:%d\n", op);
258 vss_msg->error = error;
259 len = netlink_send(fd, incoming_cn_msg);
261 syslog(LOG_ERR, "net_link send failed; error:%d %s",
262 errno, strerror(errno));