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-rw-r--r--tools/hv/hv_vss_daemon.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
new file mode 100644
index 000000000000..95269952aa92
--- /dev/null
+++ b/tools/hv/hv_vss_daemon.c
@@ -0,0 +1,220 @@
1/*
2 * An implementation of the host initiated guest snapshot for Hyper-V.
3 *
4 *
5 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
7 *
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.
11 *
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
16 * details.
17 *
18 */
19
20
21#include <sys/types.h>
22#include <sys/socket.h>
23#include <sys/poll.h>
24#include <linux/types.h>
25#include <stdio.h>
26#include <stdlib.h>
27#include <unistd.h>
28#include <string.h>
29#include <ctype.h>
30#include <errno.h>
31#include <arpa/inet.h>
32#include <linux/connector.h>
33#include <linux/hyperv.h>
34#include <linux/netlink.h>
35#include <syslog.h>
36
37static char vss_recv_buffer[4096];
38static char vss_send_buffer[4096];
39static struct sockaddr_nl addr;
40
41#ifndef SOL_NETLINK
42#define SOL_NETLINK 270
43#endif
44
45
46static int vss_operate(int operation)
47{
48 char *fs_op;
49 char cmd[512];
50 char buf[512];
51 FILE *file;
52 char *p;
53 char *x;
54 int error;
55
56 switch (operation) {
57 case VSS_OP_FREEZE:
58 fs_op = "-f ";
59 break;
60 case VSS_OP_THAW:
61 fs_op = "-u ";
62 break;
63 }
64
65 file = popen("mount | awk '/^\/dev\// { print $3}'", "r");
66 if (file == NULL)
67 return;
68
69 while ((p = fgets(buf, sizeof(buf), file)) != NULL) {
70 x = strchr(p, '\n');
71 *x = '\0';
72 if (!strncmp(p, "/", sizeof("/")))
73 continue;
74
75 sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, p);
76 syslog(LOG_INFO, "VSS cmd is %s\n", cmd);
77 error = system(cmd);
78 }
79 pclose(file);
80
81 sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, "/");
82 syslog(LOG_INFO, "VSS cmd is %s\n", cmd);
83 error = system(cmd);
84
85 return error;
86}
87
88static int netlink_send(int fd, struct cn_msg *msg)
89{
90 struct nlmsghdr *nlh;
91 unsigned int size;
92 struct msghdr message;
93 char buffer[64];
94 struct iovec iov[2];
95
96 size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
97
98 nlh = (struct nlmsghdr *)buffer;
99 nlh->nlmsg_seq = 0;
100 nlh->nlmsg_pid = getpid();
101 nlh->nlmsg_type = NLMSG_DONE;
102 nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
103 nlh->nlmsg_flags = 0;
104
105 iov[0].iov_base = nlh;
106 iov[0].iov_len = sizeof(*nlh);
107
108 iov[1].iov_base = msg;
109 iov[1].iov_len = size;
110
111 memset(&message, 0, sizeof(message));
112 message.msg_name = &addr;
113 message.msg_namelen = sizeof(addr);
114 message.msg_iov = iov;
115 message.msg_iovlen = 2;
116
117 return sendmsg(fd, &message, 0);
118}
119
120int main(void)
121{
122 int fd, len, nl_group;
123 int error;
124 struct cn_msg *message;
125 struct pollfd pfd;
126 struct nlmsghdr *incoming_msg;
127 struct cn_msg *incoming_cn_msg;
128 int op;
129 struct hv_vss_msg *vss_msg;
130
131 daemon(1, 0);
132 openlog("Hyper-V VSS", 0, LOG_USER);
133 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
134
135 fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
136 if (fd < 0) {
137 syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd);
138 exit(EXIT_FAILURE);
139 }
140 addr.nl_family = AF_NETLINK;
141 addr.nl_pad = 0;
142 addr.nl_pid = 0;
143 addr.nl_groups = 0;
144
145
146 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
147 if (error < 0) {
148 syslog(LOG_ERR, "bind failed; error:%d", error);
149 close(fd);
150 exit(EXIT_FAILURE);
151 }
152 nl_group = CN_VSS_IDX;
153 setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group));
154 /*
155 * Register ourselves with the kernel.
156 */
157 message = (struct cn_msg *)vss_send_buffer;
158 message->id.idx = CN_VSS_IDX;
159 message->id.val = CN_VSS_VAL;
160 message->ack = 0;
161 vss_msg = (struct hv_vss_msg *)message->data;
162 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
163
164 message->len = sizeof(struct hv_vss_msg);
165
166 len = netlink_send(fd, message);
167 if (len < 0) {
168 syslog(LOG_ERR, "netlink_send failed; error:%d", len);
169 close(fd);
170 exit(EXIT_FAILURE);
171 }
172
173 pfd.fd = fd;
174
175 while (1) {
176 struct sockaddr *addr_p = (struct sockaddr *) &addr;
177 socklen_t addr_l = sizeof(addr);
178 pfd.events = POLLIN;
179 pfd.revents = 0;
180 poll(&pfd, 1, -1);
181
182 len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0,
183 addr_p, &addr_l);
184
185 if (len < 0 || addr.nl_pid) {
186 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
187 addr.nl_pid, errno, strerror(errno));
188 close(fd);
189 return -1;
190 }
191
192 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
193
194 if (incoming_msg->nlmsg_type != NLMSG_DONE)
195 continue;
196
197 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
198 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
199 op = vss_msg->vss_hdr.operation;
200 error = HV_S_OK;
201
202 switch (op) {
203 case VSS_OP_FREEZE:
204 case VSS_OP_THAW:
205 error = vss_operate(op);
206 if (error)
207 error = HV_E_FAIL;
208 break;
209 default:
210 syslog(LOG_ERR, "Illegal op:%d\n", op);
211 }
212 vss_msg->error = error;
213 len = netlink_send(fd, incoming_cn_msg);
214 if (len < 0) {
215 syslog(LOG_ERR, "net_link send failed; error:%d", len);
216 exit(EXIT_FAILURE);
217 }
218 }
219
220}
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