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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 <sys/ioctl.h>
25#include <fcntl.h>
26#include <stdio.h>
27#include <mntent.h>
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>
34#include <linux/fs.h>
35#include <linux/connector.h>
36#include <linux/hyperv.h>
37#include <linux/netlink.h>
38#include <syslog.h>
39
40static struct sockaddr_nl addr;
41
42#ifndef SOL_NETLINK
43#define SOL_NETLINK 270
44#endif
45
46
47static 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
59static int vss_operate(int operation)
60{
61 char *fs_op;
62 char match[] = "/dev/";
63 FILE *mounts;
64 struct mntent *ent;
65 unsigned int cmd;
66 int error = 0, root_seen = 0;
67
68 switch (operation) {
69 case VSS_OP_FREEZE:
70 cmd = FIFREEZE;
71 fs_op = "freeze";
72 break;
73 case VSS_OP_THAW:
74 cmd = FITHAW;
75 fs_op = "thaw";
76 break;
77 default:
78 return -1;
79 }
80
81 mounts = setmntent("/proc/mounts", "r");
82 if (mounts == NULL)
83 return -1;
84
85 while ((ent = getmntent(mounts))) {
86 if (strncmp(ent->mnt_fsname, match, strlen(match)))
87 continue;
88 if (strcmp(ent->mnt_type, "iso9660") == 0)
89 continue;
90 if (strcmp(ent->mnt_type, "vfat") == 0)
91 continue;
92 if (strcmp(ent->mnt_dir, "/") == 0) {
93 root_seen = 1;
94 continue;
95 }
96 error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
97 }
98 endmntent(mounts);
99
100 if (root_seen) {
101 error |= vss_do_freeze("/", cmd, fs_op);
102 }
103
104 return error;
105}
106
107static int netlink_send(int fd, struct cn_msg *msg)
108{
109 struct nlmsghdr nlh = { .nlmsg_type = NLMSG_DONE };
110 unsigned int size;
111 struct msghdr message;
112 struct iovec iov[2];
113
114 size = sizeof(struct cn_msg) + msg->len;
115
116 nlh.nlmsg_pid = getpid();
117 nlh.nlmsg_len = NLMSG_LENGTH(size);
118
119 iov[0].iov_base = &nlh;
120 iov[0].iov_len = sizeof(nlh);
121
122 iov[1].iov_base = msg;
123 iov[1].iov_len = size;
124
125 memset(&message, 0, sizeof(message));
126 message.msg_name = &addr;
127 message.msg_namelen = sizeof(addr);
128 message.msg_iov = iov;
129 message.msg_iovlen = 2;
130
131 return sendmsg(fd, &message, 0);
132}
133
134int main(void)
135{
136 int fd, len, nl_group;
137 int error;
138 struct cn_msg *message;
139 struct pollfd pfd;
140 struct nlmsghdr *incoming_msg;
141 struct cn_msg *incoming_cn_msg;
142 int op;
143 struct hv_vss_msg *vss_msg;
144 char *vss_recv_buffer;
145 size_t vss_recv_buffer_len;
146
147 if (daemon(1, 0))
148 return 1;
149
150 openlog("Hyper-V VSS", 0, LOG_USER);
151 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
152
153 vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg);
154 vss_recv_buffer = calloc(1, vss_recv_buffer_len);
155 if (!vss_recv_buffer) {
156 syslog(LOG_ERR, "Failed to allocate netlink buffers");
157 exit(EXIT_FAILURE);
158 }
159
160 fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
161 if (fd < 0) {
162 syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
163 errno, strerror(errno));
164 exit(EXIT_FAILURE);
165 }
166 addr.nl_family = AF_NETLINK;
167 addr.nl_pad = 0;
168 addr.nl_pid = 0;
169 addr.nl_groups = 0;
170
171
172 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
173 if (error < 0) {
174 syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno));
175 close(fd);
176 exit(EXIT_FAILURE);
177 }
178 nl_group = CN_VSS_IDX;
179 if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
180 syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
181 close(fd);
182 exit(EXIT_FAILURE);
183 }
184 /*
185 * Register ourselves with the kernel.
186 */
187 message = (struct cn_msg *)vss_recv_buffer;
188 message->id.idx = CN_VSS_IDX;
189 message->id.val = CN_VSS_VAL;
190 message->ack = 0;
191 vss_msg = (struct hv_vss_msg *)message->data;
192 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
193
194 message->len = sizeof(struct hv_vss_msg);
195
196 len = netlink_send(fd, message);
197 if (len < 0) {
198 syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
199 close(fd);
200 exit(EXIT_FAILURE);
201 }
202
203 pfd.fd = fd;
204
205 while (1) {
206 struct sockaddr *addr_p = (struct sockaddr *) &addr;
207 socklen_t addr_l = sizeof(addr);
208 pfd.events = POLLIN;
209 pfd.revents = 0;
210
211 if (poll(&pfd, 1, -1) < 0) {
212 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
213 if (errno == EINVAL) {
214 close(fd);
215 exit(EXIT_FAILURE);
216 }
217 else
218 continue;
219 }
220
221 len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 0,
222 addr_p, &addr_l);
223
224 if (len < 0) {
225 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
226 addr.nl_pid, errno, strerror(errno));
227 close(fd);
228 return -1;
229 }
230
231 if (addr.nl_pid) {
232 syslog(LOG_WARNING,
233 "Received packet from untrusted pid:%u",
234 addr.nl_pid);
235 continue;
236 }
237
238 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
239
240 if (incoming_msg->nlmsg_type != NLMSG_DONE)
241 continue;
242
243 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
244 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
245 op = vss_msg->vss_hdr.operation;
246 error = HV_S_OK;
247
248 switch (op) {
249 case VSS_OP_FREEZE:
250 case VSS_OP_THAW:
251 error = vss_operate(op);
252 if (error)
253 error = HV_E_FAIL;
254 break;
255 default:
256 syslog(LOG_ERR, "Illegal op:%d\n", op);
257 }
258 vss_msg->error = error;
259 len = netlink_send(fd, incoming_cn_msg);
260 if (len < 0) {
261 syslog(LOG_ERR, "net_link send failed; error:%d %s",
262 errno, strerror(errno));
263 exit(EXIT_FAILURE);
264 }
265 }
266
267}
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/poll.h>
23#include <sys/ioctl.h>
24#include <sys/stat.h>
25#include <sys/sysmacros.h>
26#include <fcntl.h>
27#include <stdio.h>
28#include <mntent.h>
29#include <stdlib.h>
30#include <unistd.h>
31#include <string.h>
32#include <ctype.h>
33#include <errno.h>
34#include <linux/fs.h>
35#include <linux/major.h>
36#include <linux/hyperv.h>
37#include <syslog.h>
38#include <getopt.h>
39
40/* Don't use syslog() in the function since that can cause write to disk */
41static int vss_do_freeze(char *dir, unsigned int cmd)
42{
43 int ret, fd = open(dir, O_RDONLY);
44
45 if (fd < 0)
46 return 1;
47
48 ret = ioctl(fd, cmd, 0);
49
50 /*
51 * If a partition is mounted more than once, only the first
52 * FREEZE/THAW can succeed and the later ones will get
53 * EBUSY/EINVAL respectively: there could be 2 cases:
54 * 1) a user may mount the same partition to differnt directories
55 * by mistake or on purpose;
56 * 2) The subvolume of btrfs appears to have the same partition
57 * mounted more than once.
58 */
59 if (ret) {
60 if ((cmd == FIFREEZE && errno == EBUSY) ||
61 (cmd == FITHAW && errno == EINVAL)) {
62 close(fd);
63 return 0;
64 }
65 }
66
67 close(fd);
68 return !!ret;
69}
70
71static int vss_operate(int operation)
72{
73 char match[] = "/dev/";
74 FILE *mounts;
75 struct mntent *ent;
76 struct stat sb;
77 char errdir[1024] = {0};
78 unsigned int cmd;
79 int error = 0, root_seen = 0, save_errno = 0;
80
81 switch (operation) {
82 case VSS_OP_FREEZE:
83 cmd = FIFREEZE;
84 break;
85 case VSS_OP_THAW:
86 cmd = FITHAW;
87 break;
88 default:
89 return -1;
90 }
91
92 mounts = setmntent("/proc/mounts", "r");
93 if (mounts == NULL)
94 return -1;
95
96 while ((ent = getmntent(mounts))) {
97 if (strncmp(ent->mnt_fsname, match, strlen(match)))
98 continue;
99 if (stat(ent->mnt_fsname, &sb) == -1)
100 continue;
101 if (S_ISBLK(sb.st_mode) && major(sb.st_rdev) == LOOP_MAJOR)
102 continue;
103 if (hasmntopt(ent, MNTOPT_RO) != NULL)
104 continue;
105 if (strcmp(ent->mnt_type, "vfat") == 0)
106 continue;
107 if (strcmp(ent->mnt_dir, "/") == 0) {
108 root_seen = 1;
109 continue;
110 }
111 error |= vss_do_freeze(ent->mnt_dir, cmd);
112 if (error && operation == VSS_OP_FREEZE)
113 goto err;
114 }
115
116 endmntent(mounts);
117
118 if (root_seen) {
119 error |= vss_do_freeze("/", cmd);
120 if (error && operation == VSS_OP_FREEZE)
121 goto err;
122 }
123
124 goto out;
125err:
126 save_errno = errno;
127 if (ent) {
128 strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
129 endmntent(mounts);
130 }
131 vss_operate(VSS_OP_THAW);
132 /* Call syslog after we thaw all filesystems */
133 if (ent)
134 syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
135 errdir, save_errno, strerror(save_errno));
136 else
137 syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
138 strerror(save_errno));
139out:
140 return error;
141}
142
143void print_usage(char *argv[])
144{
145 fprintf(stderr, "Usage: %s [options]\n"
146 "Options are:\n"
147 " -n, --no-daemon stay in foreground, don't daemonize\n"
148 " -h, --help print this help\n", argv[0]);
149}
150
151int main(int argc, char *argv[])
152{
153 int vss_fd, len;
154 int error;
155 struct pollfd pfd;
156 int op;
157 struct hv_vss_msg vss_msg[1];
158 int daemonize = 1, long_index = 0, opt;
159 int in_handshake = 1;
160 __u32 kernel_modver;
161
162 static struct option long_options[] = {
163 {"help", no_argument, 0, 'h' },
164 {"no-daemon", no_argument, 0, 'n' },
165 {0, 0, 0, 0 }
166 };
167
168 while ((opt = getopt_long(argc, argv, "hn", long_options,
169 &long_index)) != -1) {
170 switch (opt) {
171 case 'n':
172 daemonize = 0;
173 break;
174 case 'h':
175 default:
176 print_usage(argv);
177 exit(EXIT_FAILURE);
178 }
179 }
180
181 if (daemonize && daemon(1, 0))
182 return 1;
183
184 openlog("Hyper-V VSS", 0, LOG_USER);
185 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
186
187 vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
188 if (vss_fd < 0) {
189 syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
190 errno, strerror(errno));
191 exit(EXIT_FAILURE);
192 }
193 /*
194 * Register ourselves with the kernel.
195 */
196 vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
197
198 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
199 if (len < 0) {
200 syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
201 errno, strerror(errno));
202 close(vss_fd);
203 exit(EXIT_FAILURE);
204 }
205
206 pfd.fd = vss_fd;
207
208 while (1) {
209 pfd.events = POLLIN;
210 pfd.revents = 0;
211
212 if (poll(&pfd, 1, -1) < 0) {
213 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
214 if (errno == EINVAL) {
215 close(vss_fd);
216 exit(EXIT_FAILURE);
217 }
218 else
219 continue;
220 }
221
222 len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
223
224 if (in_handshake) {
225 if (len != sizeof(kernel_modver)) {
226 syslog(LOG_ERR, "invalid version negotiation");
227 exit(EXIT_FAILURE);
228 }
229 kernel_modver = *(__u32 *)vss_msg;
230 in_handshake = 0;
231 syslog(LOG_INFO, "VSS: kernel module version: %d",
232 kernel_modver);
233 continue;
234 }
235
236 if (len != sizeof(struct hv_vss_msg)) {
237 syslog(LOG_ERR, "read failed; error:%d %s",
238 errno, strerror(errno));
239 close(vss_fd);
240 return EXIT_FAILURE;
241 }
242
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 syslog(LOG_INFO, "VSS: op=%s: %s\n",
251 op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
252 error ? "failed" : "succeeded");
253
254 if (error) {
255 error = HV_E_FAIL;
256 syslog(LOG_ERR, "op=%d failed!", op);
257 syslog(LOG_ERR, "report it with these files:");
258 syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
259 }
260 break;
261 case VSS_OP_HOT_BACKUP:
262 syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
263 break;
264 default:
265 syslog(LOG_ERR, "Illegal op:%d\n", op);
266 }
267 vss_msg->error = error;
268 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
269 if (len != sizeof(struct hv_vss_msg)) {
270 syslog(LOG_ERR, "write failed; error: %d %s", errno,
271 strerror(errno));
272
273 if (op == VSS_OP_FREEZE)
274 vss_operate(VSS_OP_THAW);
275 }
276 }
277
278 close(vss_fd);
279 exit(0);
280}