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 | ||
4f689190 DC |
47 | /* Don't use syslog() in the function since that can cause write to disk */ |
48 | static int vss_do_freeze(char *dir, unsigned int cmd) | |
7b413b65 OH |
49 | { |
50 | int ret, fd = open(dir, O_RDONLY); | |
51 | ||
52 | if (fd < 0) | |
53 | return 1; | |
4f689190 | 54 | |
7b413b65 | 55 | ret = ioctl(fd, cmd, 0); |
4f689190 DC |
56 | |
57 | /* | |
58 | * If a partition is mounted more than once, only the first | |
59 | * FREEZE/THAW can succeed and the later ones will get | |
60 | * EBUSY/EINVAL respectively: there could be 2 cases: | |
61 | * 1) a user may mount the same partition to differnt directories | |
62 | * by mistake or on purpose; | |
63 | * 2) The subvolume of btrfs appears to have the same partition | |
64 | * mounted more than once. | |
65 | */ | |
66 | if (ret) { | |
67 | if ((cmd == FIFREEZE && errno == EBUSY) || | |
68 | (cmd == FITHAW && errno == EINVAL)) { | |
69 | close(fd); | |
70 | return 0; | |
71 | } | |
72 | } | |
73 | ||
7b413b65 OH |
74 | close(fd); |
75 | return !!ret; | |
76 | } | |
77 | ||
96dd86fa S |
78 | static int vss_operate(int operation) |
79 | { | |
d3d1ee3a OH |
80 | char match[] = "/dev/"; |
81 | FILE *mounts; | |
82 | struct mntent *ent; | |
7b413b65 | 83 | unsigned int cmd; |
d3d1ee3a | 84 | int error = 0, root_seen = 0; |
96dd86fa S |
85 | |
86 | switch (operation) { | |
87 | case VSS_OP_FREEZE: | |
7b413b65 | 88 | cmd = FIFREEZE; |
96dd86fa S |
89 | break; |
90 | case VSS_OP_THAW: | |
7b413b65 | 91 | cmd = FITHAW; |
96dd86fa | 92 | break; |
eb8905b8 OH |
93 | default: |
94 | return -1; | |
96dd86fa S |
95 | } |
96 | ||
d3d1ee3a OH |
97 | mounts = setmntent("/proc/mounts", "r"); |
98 | if (mounts == NULL) | |
eb8905b8 | 99 | return -1; |
96dd86fa | 100 | |
0e272639 | 101 | while ((ent = getmntent(mounts))) { |
d3d1ee3a | 102 | if (strncmp(ent->mnt_fsname, match, strlen(match))) |
96dd86fa | 103 | continue; |
10b637b4 OH |
104 | if (strcmp(ent->mnt_type, "iso9660") == 0) |
105 | continue; | |
f33b2155 S |
106 | if (strcmp(ent->mnt_type, "vfat") == 0) |
107 | continue; | |
d3d1ee3a OH |
108 | if (strcmp(ent->mnt_dir, "/") == 0) { |
109 | root_seen = 1; | |
110 | continue; | |
111 | } | |
4f689190 DC |
112 | error |= vss_do_freeze(ent->mnt_dir, cmd); |
113 | if (error && operation == VSS_OP_FREEZE) | |
114 | goto err; | |
96dd86fa | 115 | } |
d3d1ee3a | 116 | endmntent(mounts); |
96dd86fa | 117 | |
d3d1ee3a | 118 | if (root_seen) { |
4f689190 DC |
119 | error |= vss_do_freeze("/", cmd); |
120 | if (error && operation == VSS_OP_FREEZE) | |
121 | goto err; | |
d3d1ee3a | 122 | } |
96dd86fa | 123 | |
4f689190 DC |
124 | return error; |
125 | err: | |
126 | endmntent(mounts); | |
127 | vss_operate(VSS_OP_THAW); | |
96dd86fa S |
128 | return error; |
129 | } | |
130 | ||
131 | static int netlink_send(int fd, struct cn_msg *msg) | |
132 | { | |
b4fb0ca2 | 133 | struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE }; |
96dd86fa S |
134 | unsigned int size; |
135 | struct msghdr message; | |
96dd86fa S |
136 | struct iovec iov[2]; |
137 | ||
2bc41ea3 | 138 | size = sizeof(struct cn_msg) + msg->len; |
96dd86fa | 139 | |
b4fb0ca2 OH |
140 | nlh.nlmsg_pid = getpid(); |
141 | nlh.nlmsg_len = NLMSG_LENGTH(size); | |
96dd86fa | 142 | |
b4fb0ca2 OH |
143 | iov[0].iov_base = &nlh; |
144 | iov[0].iov_len = sizeof(nlh); | |
96dd86fa S |
145 | |
146 | iov[1].iov_base = msg; | |
147 | iov[1].iov_len = size; | |
148 | ||
149 | memset(&message, 0, sizeof(message)); | |
150 | message.msg_name = &addr; | |
151 | message.msg_namelen = sizeof(addr); | |
152 | message.msg_iov = iov; | |
153 | message.msg_iovlen = 2; | |
154 | ||
155 | return sendmsg(fd, &message, 0); | |
156 | } | |
157 | ||
158 | int main(void) | |
159 | { | |
160 | int fd, len, nl_group; | |
161 | int error; | |
162 | struct cn_msg *message; | |
163 | struct pollfd pfd; | |
164 | struct nlmsghdr *incoming_msg; | |
165 | struct cn_msg *incoming_cn_msg; | |
166 | int op; | |
167 | struct hv_vss_msg *vss_msg; | |
b4919a5f OH |
168 | char *vss_recv_buffer; |
169 | size_t vss_recv_buffer_len; | |
96dd86fa | 170 | |
eb8905b8 OH |
171 | if (daemon(1, 0)) |
172 | return 1; | |
173 | ||
96dd86fa S |
174 | openlog("Hyper-V VSS", 0, LOG_USER); |
175 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); | |
176 | ||
269ce62b | 177 | vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); |
b4919a5f | 178 | vss_recv_buffer = calloc(1, vss_recv_buffer_len); |
269ce62b | 179 | if (!vss_recv_buffer) { |
b4919a5f OH |
180 | syslog(LOG_ERR, "Failed to allocate netlink buffers"); |
181 | exit(EXIT_FAILURE); | |
182 | } | |
183 | ||
96dd86fa S |
184 | fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); |
185 | if (fd < 0) { | |
5c289269 TH |
186 | syslog(LOG_ERR, "netlink socket creation failed; error:%d %s", |
187 | errno, strerror(errno)); | |
96dd86fa S |
188 | exit(EXIT_FAILURE); |
189 | } | |
190 | addr.nl_family = AF_NETLINK; | |
191 | addr.nl_pad = 0; | |
192 | addr.nl_pid = 0; | |
193 | addr.nl_groups = 0; | |
194 | ||
195 | ||
196 | error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); | |
197 | if (error < 0) { | |
5c289269 | 198 | syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
199 | close(fd); |
200 | exit(EXIT_FAILURE); | |
201 | } | |
202 | nl_group = CN_VSS_IDX; | |
d12e1469 TH |
203 | if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) { |
204 | syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno)); | |
205 | close(fd); | |
206 | exit(EXIT_FAILURE); | |
207 | } | |
96dd86fa S |
208 | /* |
209 | * Register ourselves with the kernel. | |
210 | */ | |
269ce62b | 211 | message = (struct cn_msg *)vss_recv_buffer; |
96dd86fa S |
212 | message->id.idx = CN_VSS_IDX; |
213 | message->id.val = CN_VSS_VAL; | |
214 | message->ack = 0; | |
215 | vss_msg = (struct hv_vss_msg *)message->data; | |
216 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER; | |
217 | ||
218 | message->len = sizeof(struct hv_vss_msg); | |
219 | ||
220 | len = netlink_send(fd, message); | |
221 | if (len < 0) { | |
5c289269 | 222 | syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
223 | close(fd); |
224 | exit(EXIT_FAILURE); | |
225 | } | |
226 | ||
227 | pfd.fd = fd; | |
228 | ||
229 | while (1) { | |
230 | struct sockaddr *addr_p = (struct sockaddr *) &addr; | |
231 | socklen_t addr_l = sizeof(addr); | |
232 | pfd.events = POLLIN; | |
233 | pfd.revents = 0; | |
9561d479 TH |
234 | |
235 | if (poll(&pfd, 1, -1) < 0) { | |
236 | syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno)); | |
237 | if (errno == EINVAL) { | |
238 | close(fd); | |
239 | exit(EXIT_FAILURE); | |
240 | } | |
241 | else | |
242 | continue; | |
243 | } | |
96dd86fa | 244 | |
b4919a5f | 245 | len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0, |
96dd86fa S |
246 | addr_p, &addr_l); |
247 | ||
5edf5ee4 | 248 | if (len < 0) { |
96dd86fa S |
249 | syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", |
250 | addr.nl_pid, errno, strerror(errno)); | |
251 | close(fd); | |
252 | return -1; | |
253 | } | |
254 | ||
5edf5ee4 | 255 | if (addr.nl_pid) { |
038336a5 S |
256 | syslog(LOG_WARNING, |
257 | "Received packet from untrusted pid:%u", | |
258 | addr.nl_pid); | |
5edf5ee4 OH |
259 | continue; |
260 | } | |
261 | ||
96dd86fa S |
262 | incoming_msg = (struct nlmsghdr *)vss_recv_buffer; |
263 | ||
264 | if (incoming_msg->nlmsg_type != NLMSG_DONE) | |
265 | continue; | |
266 | ||
267 | incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); | |
268 | vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; | |
269 | op = vss_msg->vss_hdr.operation; | |
270 | error = HV_S_OK; | |
271 | ||
272 | switch (op) { | |
273 | case VSS_OP_FREEZE: | |
274 | case VSS_OP_THAW: | |
275 | error = vss_operate(op); | |
4f689190 DC |
276 | syslog(LOG_INFO, "VSS: op=%s: %s\n", |
277 | op == VSS_OP_FREEZE ? "FREEZE" : "THAW", | |
278 | error ? "failed" : "succeeded"); | |
279 | ||
280 | if (error) { | |
96dd86fa | 281 | error = HV_E_FAIL; |
4f689190 DC |
282 | syslog(LOG_ERR, "op=%d failed!", op); |
283 | syslog(LOG_ERR, "report it with these files:"); | |
284 | syslog(LOG_ERR, "/etc/fstab and /proc/mounts"); | |
285 | } | |
96dd86fa S |
286 | break; |
287 | default: | |
288 | syslog(LOG_ERR, "Illegal op:%d\n", op); | |
289 | } | |
290 | vss_msg->error = error; | |
291 | len = netlink_send(fd, incoming_cn_msg); | |
292 | if (len < 0) { | |
5c289269 TH |
293 | syslog(LOG_ERR, "net_link send failed; error:%d %s", |
294 | errno, strerror(errno)); | |
96dd86fa S |
295 | exit(EXIT_FAILURE); |
296 | } | |
297 | } | |
298 | ||
299 | } |