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