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96dd86fa S |
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 | ||
37 | static char vss_recv_buffer[4096]; | |
38 | static char vss_send_buffer[4096]; | |
39 | static struct sockaddr_nl addr; | |
40 | ||
41 | #ifndef SOL_NETLINK | |
42 | #define SOL_NETLINK 270 | |
43 | #endif | |
44 | ||
45 | ||
46 | static 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 | ||
88 | static 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 | ||
120 | int 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 | } |