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> | |
170f4bea | 39 | #include <getopt.h> |
96dd86fa | 40 | |
96dd86fa S |
41 | static struct sockaddr_nl addr; |
42 | ||
43 | #ifndef SOL_NETLINK | |
44 | #define SOL_NETLINK 270 | |
45 | #endif | |
46 | ||
47 | ||
4f689190 DC |
48 | /* Don't use syslog() in the function since that can cause write to disk */ |
49 | static int vss_do_freeze(char *dir, unsigned int cmd) | |
7b413b65 OH |
50 | { |
51 | int ret, fd = open(dir, O_RDONLY); | |
52 | ||
53 | if (fd < 0) | |
54 | return 1; | |
4f689190 | 55 | |
7b413b65 | 56 | ret = ioctl(fd, cmd, 0); |
4f689190 DC |
57 | |
58 | /* | |
59 | * If a partition is mounted more than once, only the first | |
60 | * FREEZE/THAW can succeed and the later ones will get | |
61 | * EBUSY/EINVAL respectively: there could be 2 cases: | |
62 | * 1) a user may mount the same partition to differnt directories | |
63 | * by mistake or on purpose; | |
64 | * 2) The subvolume of btrfs appears to have the same partition | |
65 | * mounted more than once. | |
66 | */ | |
67 | if (ret) { | |
68 | if ((cmd == FIFREEZE && errno == EBUSY) || | |
69 | (cmd == FITHAW && errno == EINVAL)) { | |
70 | close(fd); | |
71 | return 0; | |
72 | } | |
73 | } | |
74 | ||
7b413b65 OH |
75 | close(fd); |
76 | return !!ret; | |
77 | } | |
78 | ||
96dd86fa S |
79 | static int vss_operate(int operation) |
80 | { | |
d3d1ee3a OH |
81 | char match[] = "/dev/"; |
82 | FILE *mounts; | |
83 | struct mntent *ent; | |
4ce50e94 | 84 | char errdir[1024] = {0}; |
7b413b65 | 85 | unsigned int cmd; |
7a401744 | 86 | int error = 0, root_seen = 0, save_errno = 0; |
96dd86fa S |
87 | |
88 | switch (operation) { | |
89 | case VSS_OP_FREEZE: | |
7b413b65 | 90 | cmd = FIFREEZE; |
96dd86fa S |
91 | break; |
92 | case VSS_OP_THAW: | |
7b413b65 | 93 | cmd = FITHAW; |
96dd86fa | 94 | break; |
eb8905b8 OH |
95 | default: |
96 | return -1; | |
96dd86fa S |
97 | } |
98 | ||
d3d1ee3a OH |
99 | mounts = setmntent("/proc/mounts", "r"); |
100 | if (mounts == NULL) | |
eb8905b8 | 101 | return -1; |
96dd86fa | 102 | |
0e272639 | 103 | while ((ent = getmntent(mounts))) { |
d3d1ee3a | 104 | if (strncmp(ent->mnt_fsname, match, strlen(match))) |
96dd86fa | 105 | continue; |
9e5db05a | 106 | if (hasmntopt(ent, MNTOPT_RO) != NULL) |
10b637b4 | 107 | continue; |
f33b2155 S |
108 | if (strcmp(ent->mnt_type, "vfat") == 0) |
109 | continue; | |
d3d1ee3a OH |
110 | if (strcmp(ent->mnt_dir, "/") == 0) { |
111 | root_seen = 1; | |
112 | continue; | |
113 | } | |
4f689190 DC |
114 | error |= vss_do_freeze(ent->mnt_dir, cmd); |
115 | if (error && operation == VSS_OP_FREEZE) | |
116 | goto err; | |
96dd86fa | 117 | } |
96dd86fa | 118 | |
4ce50e94 VC |
119 | endmntent(mounts); |
120 | ||
d3d1ee3a | 121 | if (root_seen) { |
4f689190 DC |
122 | error |= vss_do_freeze("/", cmd); |
123 | if (error && operation == VSS_OP_FREEZE) | |
124 | goto err; | |
d3d1ee3a | 125 | } |
96dd86fa | 126 | |
7a401744 | 127 | goto out; |
4f689190 | 128 | err: |
7a401744 | 129 | save_errno = errno; |
4ce50e94 VC |
130 | if (ent) { |
131 | strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1); | |
132 | endmntent(mounts); | |
133 | } | |
4f689190 | 134 | vss_operate(VSS_OP_THAW); |
7a401744 VK |
135 | /* Call syslog after we thaw all filesystems */ |
136 | if (ent) | |
137 | syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s", | |
4ce50e94 | 138 | errdir, save_errno, strerror(save_errno)); |
7a401744 VK |
139 | else |
140 | syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno, | |
141 | strerror(save_errno)); | |
142 | out: | |
96dd86fa S |
143 | return error; |
144 | } | |
145 | ||
146 | static int netlink_send(int fd, struct cn_msg *msg) | |
147 | { | |
b4fb0ca2 | 148 | struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE }; |
96dd86fa S |
149 | unsigned int size; |
150 | struct msghdr message; | |
96dd86fa S |
151 | struct iovec iov[2]; |
152 | ||
2bc41ea3 | 153 | size = sizeof(struct cn_msg) + msg->len; |
96dd86fa | 154 | |
b4fb0ca2 OH |
155 | nlh.nlmsg_pid = getpid(); |
156 | nlh.nlmsg_len = NLMSG_LENGTH(size); | |
96dd86fa | 157 | |
b4fb0ca2 OH |
158 | iov[0].iov_base = &nlh; |
159 | iov[0].iov_len = sizeof(nlh); | |
96dd86fa S |
160 | |
161 | iov[1].iov_base = msg; | |
162 | iov[1].iov_len = size; | |
163 | ||
164 | memset(&message, 0, sizeof(message)); | |
165 | message.msg_name = &addr; | |
166 | message.msg_namelen = sizeof(addr); | |
167 | message.msg_iov = iov; | |
168 | message.msg_iovlen = 2; | |
169 | ||
170 | return sendmsg(fd, &message, 0); | |
171 | } | |
172 | ||
170f4bea VK |
173 | void print_usage(char *argv[]) |
174 | { | |
175 | fprintf(stderr, "Usage: %s [options]\n" | |
176 | "Options are:\n" | |
177 | " -n, --no-daemon stay in foreground, don't daemonize\n" | |
178 | " -h, --help print this help\n", argv[0]); | |
179 | } | |
180 | ||
181 | int main(int argc, char *argv[]) | |
96dd86fa S |
182 | { |
183 | int fd, len, nl_group; | |
184 | int error; | |
185 | struct cn_msg *message; | |
186 | struct pollfd pfd; | |
187 | struct nlmsghdr *incoming_msg; | |
188 | struct cn_msg *incoming_cn_msg; | |
189 | int op; | |
190 | struct hv_vss_msg *vss_msg; | |
b4919a5f OH |
191 | char *vss_recv_buffer; |
192 | size_t vss_recv_buffer_len; | |
170f4bea VK |
193 | int daemonize = 1, long_index = 0, opt; |
194 | ||
195 | static struct option long_options[] = { | |
196 | {"help", no_argument, 0, 'h' }, | |
197 | {"no-daemon", no_argument, 0, 'n' }, | |
198 | {0, 0, 0, 0 } | |
199 | }; | |
200 | ||
201 | while ((opt = getopt_long(argc, argv, "hn", long_options, | |
202 | &long_index)) != -1) { | |
203 | switch (opt) { | |
204 | case 'n': | |
205 | daemonize = 0; | |
206 | break; | |
207 | case 'h': | |
208 | default: | |
209 | print_usage(argv); | |
210 | exit(EXIT_FAILURE); | |
211 | } | |
212 | } | |
96dd86fa | 213 | |
170f4bea | 214 | if (daemonize && daemon(1, 0)) |
eb8905b8 OH |
215 | return 1; |
216 | ||
96dd86fa S |
217 | openlog("Hyper-V VSS", 0, LOG_USER); |
218 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); | |
219 | ||
269ce62b | 220 | vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg); |
b4919a5f | 221 | vss_recv_buffer = calloc(1, vss_recv_buffer_len); |
269ce62b | 222 | if (!vss_recv_buffer) { |
b4919a5f OH |
223 | syslog(LOG_ERR, "Failed to allocate netlink buffers"); |
224 | exit(EXIT_FAILURE); | |
225 | } | |
226 | ||
96dd86fa S |
227 | fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); |
228 | if (fd < 0) { | |
5c289269 TH |
229 | syslog(LOG_ERR, "netlink socket creation failed; error:%d %s", |
230 | errno, strerror(errno)); | |
96dd86fa S |
231 | exit(EXIT_FAILURE); |
232 | } | |
233 | addr.nl_family = AF_NETLINK; | |
234 | addr.nl_pad = 0; | |
235 | addr.nl_pid = 0; | |
236 | addr.nl_groups = 0; | |
237 | ||
238 | ||
239 | error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); | |
240 | if (error < 0) { | |
5c289269 | 241 | syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
242 | close(fd); |
243 | exit(EXIT_FAILURE); | |
244 | } | |
245 | nl_group = CN_VSS_IDX; | |
d12e1469 TH |
246 | if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) { |
247 | syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno)); | |
248 | close(fd); | |
249 | exit(EXIT_FAILURE); | |
250 | } | |
96dd86fa S |
251 | /* |
252 | * Register ourselves with the kernel. | |
253 | */ | |
269ce62b | 254 | message = (struct cn_msg *)vss_recv_buffer; |
96dd86fa S |
255 | message->id.idx = CN_VSS_IDX; |
256 | message->id.val = CN_VSS_VAL; | |
257 | message->ack = 0; | |
258 | vss_msg = (struct hv_vss_msg *)message->data; | |
259 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER; | |
260 | ||
261 | message->len = sizeof(struct hv_vss_msg); | |
262 | ||
263 | len = netlink_send(fd, message); | |
264 | if (len < 0) { | |
5c289269 | 265 | syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno)); |
96dd86fa S |
266 | close(fd); |
267 | exit(EXIT_FAILURE); | |
268 | } | |
269 | ||
270 | pfd.fd = fd; | |
271 | ||
272 | while (1) { | |
273 | struct sockaddr *addr_p = (struct sockaddr *) &addr; | |
274 | socklen_t addr_l = sizeof(addr); | |
275 | pfd.events = POLLIN; | |
276 | pfd.revents = 0; | |
9561d479 TH |
277 | |
278 | if (poll(&pfd, 1, -1) < 0) { | |
279 | syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno)); | |
280 | if (errno == EINVAL) { | |
281 | close(fd); | |
282 | exit(EXIT_FAILURE); | |
283 | } | |
284 | else | |
285 | continue; | |
286 | } | |
96dd86fa | 287 | |
b4919a5f | 288 | len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0, |
96dd86fa S |
289 | addr_p, &addr_l); |
290 | ||
5edf5ee4 | 291 | if (len < 0) { |
96dd86fa S |
292 | syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", |
293 | addr.nl_pid, errno, strerror(errno)); | |
294 | close(fd); | |
295 | return -1; | |
296 | } | |
297 | ||
5edf5ee4 | 298 | if (addr.nl_pid) { |
038336a5 S |
299 | syslog(LOG_WARNING, |
300 | "Received packet from untrusted pid:%u", | |
301 | addr.nl_pid); | |
5edf5ee4 OH |
302 | continue; |
303 | } | |
304 | ||
96dd86fa S |
305 | incoming_msg = (struct nlmsghdr *)vss_recv_buffer; |
306 | ||
307 | if (incoming_msg->nlmsg_type != NLMSG_DONE) | |
308 | continue; | |
309 | ||
310 | incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); | |
311 | vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; | |
312 | op = vss_msg->vss_hdr.operation; | |
313 | error = HV_S_OK; | |
314 | ||
315 | switch (op) { | |
316 | case VSS_OP_FREEZE: | |
317 | case VSS_OP_THAW: | |
318 | error = vss_operate(op); | |
4f689190 DC |
319 | syslog(LOG_INFO, "VSS: op=%s: %s\n", |
320 | op == VSS_OP_FREEZE ? "FREEZE" : "THAW", | |
321 | error ? "failed" : "succeeded"); | |
322 | ||
323 | if (error) { | |
96dd86fa | 324 | error = HV_E_FAIL; |
4f689190 DC |
325 | syslog(LOG_ERR, "op=%d failed!", op); |
326 | syslog(LOG_ERR, "report it with these files:"); | |
327 | syslog(LOG_ERR, "/etc/fstab and /proc/mounts"); | |
328 | } | |
96dd86fa S |
329 | break; |
330 | default: | |
331 | syslog(LOG_ERR, "Illegal op:%d\n", op); | |
332 | } | |
333 | vss_msg->error = error; | |
334 | len = netlink_send(fd, incoming_cn_msg); | |
335 | if (len < 0) { | |
5c289269 TH |
336 | syslog(LOG_ERR, "net_link send failed; error:%d %s", |
337 | errno, strerror(errno)); | |
96dd86fa S |
338 | exit(EXIT_FAILURE); |
339 | } | |
340 | } | |
341 | ||
342 | } |