Commit | Line | Data |
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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> | |
7b413b65 | 24 | #include <sys/ioctl.h> |
7b413b65 | 25 | #include <fcntl.h> |
96dd86fa | 26 | #include <stdio.h> |
d3d1ee3a | 27 | #include <mntent.h> |
96dd86fa S |
28 | #include <stdlib.h> |
29 | #include <unistd.h> | |
30 | #include <string.h> | |
31 | #include <ctype.h> | |
32 | #include <errno.h> | |
33 | #include <arpa/inet.h> | |
7b413b65 | 34 | #include <linux/fs.h> |
96dd86fa S |
35 | #include <linux/connector.h> |
36 | #include <linux/hyperv.h> | |
37 | #include <linux/netlink.h> | |
38 | #include <syslog.h> | |
39 | ||
96dd86fa S |
40 | static struct sockaddr_nl addr; |
41 | ||
42 | #ifndef SOL_NETLINK | |
43 | #define SOL_NETLINK 270 | |
44 | #endif | |
45 | ||
46 | ||
7b413b65 OH |
47 | static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op) |
48 | { | |
49 | int ret, fd = open(dir, O_RDONLY); | |
50 | ||
51 | if (fd < 0) | |
52 | return 1; | |
53 | ret = ioctl(fd, cmd, 0); | |
54 | syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno)); | |
55 | close(fd); | |
56 | return !!ret; | |
57 | } | |
58 | ||
96dd86fa S |
59 | static int vss_operate(int operation) |
60 | { | |
61 | char *fs_op; | |
d3d1ee3a OH |
62 | char match[] = "/dev/"; |
63 | FILE *mounts; | |
64 | struct mntent *ent; | |
7b413b65 | 65 | unsigned int cmd; |
d3d1ee3a | 66 | int error = 0, root_seen = 0; |
96dd86fa S |
67 | |
68 | switch (operation) { | |
69 | case VSS_OP_FREEZE: | |
7b413b65 OH |
70 | cmd = FIFREEZE; |
71 | fs_op = "freeze"; | |
96dd86fa S |
72 | break; |
73 | case VSS_OP_THAW: | |
7b413b65 OH |
74 | cmd = FITHAW; |
75 | fs_op = "thaw"; | |
96dd86fa | 76 | break; |
eb8905b8 OH |
77 | default: |
78 | return -1; | |
96dd86fa S |
79 | } |
80 | ||
d3d1ee3a OH |
81 | mounts = setmntent("/proc/mounts", "r"); |
82 | if (mounts == NULL) | |
eb8905b8 | 83 | return -1; |
96dd86fa | 84 | |
0e272639 | 85 | while ((ent = getmntent(mounts))) { |
d3d1ee3a | 86 | if (strncmp(ent->mnt_fsname, match, strlen(match))) |
96dd86fa | 87 | continue; |
10b637b4 OH |
88 | if (strcmp(ent->mnt_type, "iso9660") == 0) |
89 | continue; | |
d3d1ee3a OH |
90 | if (strcmp(ent->mnt_dir, "/") == 0) { |
91 | root_seen = 1; | |
92 | continue; | |
93 | } | |
7b413b65 | 94 | error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op); |
96dd86fa | 95 | } |
d3d1ee3a | 96 | endmntent(mounts); |
96dd86fa | 97 | |
d3d1ee3a | 98 | if (root_seen) { |
7b413b65 | 99 | error |= vss_do_freeze("/", cmd, fs_op); |
d3d1ee3a | 100 | } |
96dd86fa S |
101 | |
102 | return error; | |
103 | } | |
104 | ||
105 | static int netlink_send(int fd, struct cn_msg *msg) | |
106 | { | |
b4fb0ca2 | 107 | struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE }; |
96dd86fa S |
108 | unsigned int size; |
109 | struct msghdr message; | |
96dd86fa S |
110 | struct iovec iov[2]; |
111 | ||
2bc41ea3 | 112 | size = sizeof(struct cn_msg) + msg->len; |
96dd86fa | 113 | |
b4fb0ca2 OH |
114 | nlh.nlmsg_pid = getpid(); |
115 | nlh.nlmsg_len = NLMSG_LENGTH(size); | |
96dd86fa | 116 | |
b4fb0ca2 OH |
117 | iov[0].iov_base = &nlh; |
118 | iov[0].iov_len = sizeof(nlh); | |
96dd86fa S |
119 | |
120 | iov[1].iov_base = msg; | |
121 | iov[1].iov_len = size; | |
122 | ||
123 | memset(&message, 0, sizeof(message)); | |
124 | message.msg_name = &addr; | |
125 | message.msg_namelen = sizeof(addr); | |
126 | message.msg_iov = iov; | |
127 | message.msg_iovlen = 2; | |
128 | ||
129 | return sendmsg(fd, &message, 0); | |
130 | } | |
131 | ||
132 | int main(void) | |
133 | { | |
134 | int fd, len, nl_group; | |
135 | int error; | |
136 | struct cn_msg *message; | |
137 | struct pollfd pfd; | |
138 | struct nlmsghdr *incoming_msg; | |
139 | struct cn_msg *incoming_cn_msg; | |
140 | int op; | |
141 | struct hv_vss_msg *vss_msg; | |
b4919a5f OH |
142 | char *vss_recv_buffer; |
143 | size_t vss_recv_buffer_len; | |
96dd86fa | 144 | |
eb8905b8 OH |
145 | if (daemon(1, 0)) |
146 | return 1; | |
147 | ||
96dd86fa S |
148 | openlog("Hyper-V VSS", 0, LOG_USER); |
149 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); | |
150 | ||
269ce62b | 151 | vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); |
b4919a5f | 152 | vss_recv_buffer = calloc(1, vss_recv_buffer_len); |
269ce62b | 153 | if (!vss_recv_buffer) { |
b4919a5f OH |
154 | syslog(LOG_ERR, "Failed to allocate netlink buffers"); |
155 | exit(EXIT_FAILURE); | |
156 | } | |
157 | ||
96dd86fa S |
158 | fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); |
159 | if (fd < 0) { | |
5c289269 TH |
160 | syslog(LOG_ERR, "netlink socket creation failed; error:%d %s", |
161 | errno, strerror(errno)); | |
96dd86fa S |
162 | exit(EXIT_FAILURE); |
163 | } | |
164 | addr.nl_family = AF_NETLINK; | |
165 | addr.nl_pad = 0; | |
166 | addr.nl_pid = 0; | |
167 | addr.nl_groups = 0; | |
168 | ||
169 | ||
170 | error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); | |
171 | if (error < 0) { | |
5c289269 | 172 | syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
173 | close(fd); |
174 | exit(EXIT_FAILURE); | |
175 | } | |
176 | nl_group = CN_VSS_IDX; | |
d12e1469 TH |
177 | if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) { |
178 | syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno)); | |
179 | close(fd); | |
180 | exit(EXIT_FAILURE); | |
181 | } | |
96dd86fa S |
182 | /* |
183 | * Register ourselves with the kernel. | |
184 | */ | |
269ce62b | 185 | message = (struct cn_msg *)vss_recv_buffer; |
96dd86fa S |
186 | message->id.idx = CN_VSS_IDX; |
187 | message->id.val = CN_VSS_VAL; | |
188 | message->ack = 0; | |
189 | vss_msg = (struct hv_vss_msg *)message->data; | |
190 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER; | |
191 | ||
192 | message->len = sizeof(struct hv_vss_msg); | |
193 | ||
194 | len = netlink_send(fd, message); | |
195 | if (len < 0) { | |
5c289269 | 196 | syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
197 | close(fd); |
198 | exit(EXIT_FAILURE); | |
199 | } | |
200 | ||
201 | pfd.fd = fd; | |
202 | ||
203 | while (1) { | |
204 | struct sockaddr *addr_p = (struct sockaddr *) &addr; | |
205 | socklen_t addr_l = sizeof(addr); | |
206 | pfd.events = POLLIN; | |
207 | pfd.revents = 0; | |
9561d479 TH |
208 | |
209 | if (poll(&pfd, 1, -1) < 0) { | |
210 | syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno)); | |
211 | if (errno == EINVAL) { | |
212 | close(fd); | |
213 | exit(EXIT_FAILURE); | |
214 | } | |
215 | else | |
216 | continue; | |
217 | } | |
96dd86fa | 218 | |
b4919a5f | 219 | len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0, |
96dd86fa S |
220 | addr_p, &addr_l); |
221 | ||
5edf5ee4 | 222 | if (len < 0) { |
96dd86fa S |
223 | syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", |
224 | addr.nl_pid, errno, strerror(errno)); | |
225 | close(fd); | |
226 | return -1; | |
227 | } | |
228 | ||
5edf5ee4 | 229 | if (addr.nl_pid) { |
038336a5 S |
230 | syslog(LOG_WARNING, |
231 | "Received packet from untrusted pid:%u", | |
232 | addr.nl_pid); | |
5edf5ee4 OH |
233 | continue; |
234 | } | |
235 | ||
96dd86fa S |
236 | incoming_msg = (struct nlmsghdr *)vss_recv_buffer; |
237 | ||
238 | if (incoming_msg->nlmsg_type != NLMSG_DONE) | |
239 | continue; | |
240 | ||
241 | incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); | |
242 | vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; | |
243 | op = vss_msg->vss_hdr.operation; | |
244 | error = HV_S_OK; | |
245 | ||
246 | switch (op) { | |
247 | case VSS_OP_FREEZE: | |
248 | case VSS_OP_THAW: | |
249 | error = vss_operate(op); | |
250 | if (error) | |
251 | error = HV_E_FAIL; | |
252 | break; | |
253 | default: | |
254 | syslog(LOG_ERR, "Illegal op:%d\n", op); | |
255 | } | |
256 | vss_msg->error = error; | |
257 | len = netlink_send(fd, incoming_cn_msg); | |
258 | if (len < 0) { | |
5c289269 TH |
259 | syslog(LOG_ERR, "net_link send failed; error:%d %s", |
260 | errno, strerror(errno)); | |
96dd86fa S |
261 | exit(EXIT_FAILURE); |
262 | } | |
263 | } | |
264 | ||
265 | } |