This source file includes following definitions.
- vss_do_freeze
- is_dev_loop
- vss_operate
- print_usage
- main
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10 #include <sys/types.h>
11 #include <sys/poll.h>
12 #include <sys/ioctl.h>
13 #include <sys/stat.h>
14 #include <sys/sysmacros.h>
15 #include <fcntl.h>
16 #include <stdio.h>
17 #include <mntent.h>
18 #include <stdlib.h>
19 #include <unistd.h>
20 #include <string.h>
21 #include <ctype.h>
22 #include <errno.h>
23 #include <linux/fs.h>
24 #include <linux/major.h>
25 #include <linux/hyperv.h>
26 #include <syslog.h>
27 #include <getopt.h>
28 #include <stdbool.h>
29 #include <dirent.h>
30
31
32 static int vss_do_freeze(char *dir, unsigned int cmd)
33 {
34 int ret, fd = open(dir, O_RDONLY);
35
36 if (fd < 0)
37 return 1;
38
39 ret = ioctl(fd, cmd, 0);
40
41
42
43
44
45
46
47
48
49
50 if (ret) {
51 if ((cmd == FIFREEZE && errno == EBUSY) ||
52 (cmd == FITHAW && errno == EINVAL)) {
53 close(fd);
54 return 0;
55 }
56 }
57
58 close(fd);
59 return !!ret;
60 }
61
62 static bool is_dev_loop(const char *blkname)
63 {
64 char *buffer;
65 DIR *dir;
66 struct dirent *entry;
67 bool ret = false;
68
69 buffer = malloc(PATH_MAX);
70 if (!buffer) {
71 syslog(LOG_ERR, "Can't allocate memory!");
72 exit(1);
73 }
74
75 snprintf(buffer, PATH_MAX, "%s/loop", blkname);
76 if (!access(buffer, R_OK | X_OK)) {
77 ret = true;
78 goto free_buffer;
79 } else if (errno != ENOENT) {
80 syslog(LOG_ERR, "Can't access: %s; error:%d %s!",
81 buffer, errno, strerror(errno));
82 }
83
84 snprintf(buffer, PATH_MAX, "%s/slaves", blkname);
85 dir = opendir(buffer);
86 if (!dir) {
87 if (errno != ENOENT)
88 syslog(LOG_ERR, "Can't opendir: %s; error:%d %s!",
89 buffer, errno, strerror(errno));
90 goto free_buffer;
91 }
92
93 while ((entry = readdir(dir)) != NULL) {
94 if (strcmp(entry->d_name, ".") == 0 ||
95 strcmp(entry->d_name, "..") == 0)
96 continue;
97
98 snprintf(buffer, PATH_MAX, "%s/slaves/%s", blkname,
99 entry->d_name);
100 if (is_dev_loop(buffer)) {
101 ret = true;
102 break;
103 }
104 }
105 closedir(dir);
106 free_buffer:
107 free(buffer);
108 return ret;
109 }
110
111 static int vss_operate(int operation)
112 {
113 char match[] = "/dev/";
114 FILE *mounts;
115 struct mntent *ent;
116 struct stat sb;
117 char errdir[1024] = {0};
118 char blkdir[23];
119 unsigned int cmd;
120 int error = 0, root_seen = 0, save_errno = 0;
121
122 switch (operation) {
123 case VSS_OP_FREEZE:
124 cmd = FIFREEZE;
125 break;
126 case VSS_OP_THAW:
127 cmd = FITHAW;
128 break;
129 default:
130 return -1;
131 }
132
133 mounts = setmntent("/proc/mounts", "r");
134 if (mounts == NULL)
135 return -1;
136
137 while ((ent = getmntent(mounts))) {
138 if (strncmp(ent->mnt_fsname, match, strlen(match)))
139 continue;
140 if (stat(ent->mnt_fsname, &sb)) {
141 syslog(LOG_ERR, "Can't stat: %s; error:%d %s!",
142 ent->mnt_fsname, errno, strerror(errno));
143 } else {
144 sprintf(blkdir, "/sys/dev/block/%d:%d",
145 major(sb.st_rdev), minor(sb.st_rdev));
146 if (is_dev_loop(blkdir))
147 continue;
148 }
149 if (hasmntopt(ent, MNTOPT_RO) != NULL)
150 continue;
151 if (strcmp(ent->mnt_type, "vfat") == 0)
152 continue;
153 if (strcmp(ent->mnt_dir, "/") == 0) {
154 root_seen = 1;
155 continue;
156 }
157 error |= vss_do_freeze(ent->mnt_dir, cmd);
158 if (error && operation == VSS_OP_FREEZE)
159 goto err;
160 }
161
162 endmntent(mounts);
163
164 if (root_seen) {
165 error |= vss_do_freeze("/", cmd);
166 if (error && operation == VSS_OP_FREEZE)
167 goto err;
168 }
169
170 goto out;
171 err:
172 save_errno = errno;
173 if (ent) {
174 strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
175 endmntent(mounts);
176 }
177 vss_operate(VSS_OP_THAW);
178
179 if (ent)
180 syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
181 errdir, save_errno, strerror(save_errno));
182 else
183 syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
184 strerror(save_errno));
185 out:
186 return error;
187 }
188
189 void print_usage(char *argv[])
190 {
191 fprintf(stderr, "Usage: %s [options]\n"
192 "Options are:\n"
193 " -n, --no-daemon stay in foreground, don't daemonize\n"
194 " -h, --help print this help\n", argv[0]);
195 }
196
197 int main(int argc, char *argv[])
198 {
199 int vss_fd, len;
200 int error;
201 struct pollfd pfd;
202 int op;
203 struct hv_vss_msg vss_msg[1];
204 int daemonize = 1, long_index = 0, opt;
205 int in_handshake = 1;
206 __u32 kernel_modver;
207
208 static struct option long_options[] = {
209 {"help", no_argument, 0, 'h' },
210 {"no-daemon", no_argument, 0, 'n' },
211 {0, 0, 0, 0 }
212 };
213
214 while ((opt = getopt_long(argc, argv, "hn", long_options,
215 &long_index)) != -1) {
216 switch (opt) {
217 case 'n':
218 daemonize = 0;
219 break;
220 case 'h':
221 print_usage(argv);
222 exit(0);
223 default:
224 print_usage(argv);
225 exit(EXIT_FAILURE);
226 }
227 }
228
229 if (daemonize && daemon(1, 0))
230 return 1;
231
232 openlog("Hyper-V VSS", 0, LOG_USER);
233 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
234
235 vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
236 if (vss_fd < 0) {
237 syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
238 errno, strerror(errno));
239 exit(EXIT_FAILURE);
240 }
241
242
243
244 vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
245
246 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
247 if (len < 0) {
248 syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
249 errno, strerror(errno));
250 close(vss_fd);
251 exit(EXIT_FAILURE);
252 }
253
254 pfd.fd = vss_fd;
255
256 while (1) {
257 pfd.events = POLLIN;
258 pfd.revents = 0;
259
260 if (poll(&pfd, 1, -1) < 0) {
261 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
262 if (errno == EINVAL) {
263 close(vss_fd);
264 exit(EXIT_FAILURE);
265 }
266 else
267 continue;
268 }
269
270 len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
271
272 if (in_handshake) {
273 if (len != sizeof(kernel_modver)) {
274 syslog(LOG_ERR, "invalid version negotiation");
275 exit(EXIT_FAILURE);
276 }
277 kernel_modver = *(__u32 *)vss_msg;
278 in_handshake = 0;
279 syslog(LOG_INFO, "VSS: kernel module version: %d",
280 kernel_modver);
281 continue;
282 }
283
284 if (len != sizeof(struct hv_vss_msg)) {
285 syslog(LOG_ERR, "read failed; error:%d %s",
286 errno, strerror(errno));
287 close(vss_fd);
288 return EXIT_FAILURE;
289 }
290
291 op = vss_msg->vss_hdr.operation;
292 error = HV_S_OK;
293
294 switch (op) {
295 case VSS_OP_FREEZE:
296 case VSS_OP_THAW:
297 error = vss_operate(op);
298 syslog(LOG_INFO, "VSS: op=%s: %s\n",
299 op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
300 error ? "failed" : "succeeded");
301
302 if (error) {
303 error = HV_E_FAIL;
304 syslog(LOG_ERR, "op=%d failed!", op);
305 syslog(LOG_ERR, "report it with these files:");
306 syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
307 }
308 break;
309 case VSS_OP_HOT_BACKUP:
310 syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
311 break;
312 default:
313 syslog(LOG_ERR, "Illegal op:%d\n", op);
314 }
315 vss_msg->error = error;
316 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
317 if (len != sizeof(struct hv_vss_msg)) {
318 syslog(LOG_ERR, "write failed; error: %d %s", errno,
319 strerror(errno));
320
321 if (op == VSS_OP_FREEZE)
322 vss_operate(VSS_OP_THAW);
323 }
324 }
325
326 close(vss_fd);
327 exit(0);
328 }