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21#include <sys/types.h>
22#include <sys/poll.h>
23#include <sys/ioctl.h>
24#include <sys/stat.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 <linux/fs.h>
34#include <linux/major.h>
35#include <linux/hyperv.h>
36#include <syslog.h>
37#include <getopt.h>
38
39
40static int vss_do_freeze(char *dir, unsigned int cmd)
41{
42 int ret, fd = open(dir, O_RDONLY);
43
44 if (fd < 0)
45 return 1;
46
47 ret = ioctl(fd, cmd, 0);
48
49
50
51
52
53
54
55
56
57
58 if (ret) {
59 if ((cmd == FIFREEZE && errno == EBUSY) ||
60 (cmd == FITHAW && errno == EINVAL)) {
61 close(fd);
62 return 0;
63 }
64 }
65
66 close(fd);
67 return !!ret;
68}
69
70static int vss_operate(int operation)
71{
72 char match[] = "/dev/";
73 FILE *mounts;
74 struct mntent *ent;
75 struct stat sb;
76 char errdir[1024] = {0};
77 unsigned int cmd;
78 int error = 0, root_seen = 0, save_errno = 0;
79
80 switch (operation) {
81 case VSS_OP_FREEZE:
82 cmd = FIFREEZE;
83 break;
84 case VSS_OP_THAW:
85 cmd = FITHAW;
86 break;
87 default:
88 return -1;
89 }
90
91 mounts = setmntent("/proc/mounts", "r");
92 if (mounts == NULL)
93 return -1;
94
95 while ((ent = getmntent(mounts))) {
96 if (strncmp(ent->mnt_fsname, match, strlen(match)))
97 continue;
98 if (stat(ent->mnt_fsname, &sb) == -1)
99 continue;
100 if (S_ISBLK(sb.st_mode) && major(sb.st_rdev) == LOOP_MAJOR)
101 continue;
102 if (hasmntopt(ent, MNTOPT_RO) != NULL)
103 continue;
104 if (strcmp(ent->mnt_type, "vfat") == 0)
105 continue;
106 if (strcmp(ent->mnt_dir, "/") == 0) {
107 root_seen = 1;
108 continue;
109 }
110 error |= vss_do_freeze(ent->mnt_dir, cmd);
111 if (error && operation == VSS_OP_FREEZE)
112 goto err;
113 }
114
115 endmntent(mounts);
116
117 if (root_seen) {
118 error |= vss_do_freeze("/", cmd);
119 if (error && operation == VSS_OP_FREEZE)
120 goto err;
121 }
122
123 goto out;
124err:
125 save_errno = errno;
126 if (ent) {
127 strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
128 endmntent(mounts);
129 }
130 vss_operate(VSS_OP_THAW);
131
132 if (ent)
133 syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
134 errdir, save_errno, strerror(save_errno));
135 else
136 syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
137 strerror(save_errno));
138out:
139 return error;
140}
141
142void print_usage(char *argv[])
143{
144 fprintf(stderr, "Usage: %s [options]\n"
145 "Options are:\n"
146 " -n, --no-daemon stay in foreground, don't daemonize\n"
147 " -h, --help print this help\n", argv[0]);
148}
149
150int main(int argc, char *argv[])
151{
152 int vss_fd, len;
153 int error;
154 struct pollfd pfd;
155 int op;
156 struct hv_vss_msg vss_msg[1];
157 int daemonize = 1, long_index = 0, opt;
158 int in_handshake = 1;
159 __u32 kernel_modver;
160
161 static struct option long_options[] = {
162 {"help", no_argument, 0, 'h' },
163 {"no-daemon", no_argument, 0, 'n' },
164 {0, 0, 0, 0 }
165 };
166
167 while ((opt = getopt_long(argc, argv, "hn", long_options,
168 &long_index)) != -1) {
169 switch (opt) {
170 case 'n':
171 daemonize = 0;
172 break;
173 case 'h':
174 default:
175 print_usage(argv);
176 exit(EXIT_FAILURE);
177 }
178 }
179
180 if (daemonize && daemon(1, 0))
181 return 1;
182
183 openlog("Hyper-V VSS", 0, LOG_USER);
184 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
185
186 vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
187 if (vss_fd < 0) {
188 syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
189 errno, strerror(errno));
190 exit(EXIT_FAILURE);
191 }
192
193
194
195 vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
196
197 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
198 if (len < 0) {
199 syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
200 errno, strerror(errno));
201 close(vss_fd);
202 exit(EXIT_FAILURE);
203 }
204
205 pfd.fd = vss_fd;
206
207 while (1) {
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(vss_fd);
215 exit(EXIT_FAILURE);
216 }
217 else
218 continue;
219 }
220
221 len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
222
223 if (in_handshake) {
224 if (len != sizeof(kernel_modver)) {
225 syslog(LOG_ERR, "invalid version negotiation");
226 exit(EXIT_FAILURE);
227 }
228 kernel_modver = *(__u32 *)vss_msg;
229 in_handshake = 0;
230 syslog(LOG_INFO, "VSS: kernel module version: %d",
231 kernel_modver);
232 continue;
233 }
234
235 if (len != sizeof(struct hv_vss_msg)) {
236 syslog(LOG_ERR, "read failed; error:%d %s",
237 errno, strerror(errno));
238 close(vss_fd);
239 return EXIT_FAILURE;
240 }
241
242 op = vss_msg->vss_hdr.operation;
243 error = HV_S_OK;
244
245 switch (op) {
246 case VSS_OP_FREEZE:
247 case VSS_OP_THAW:
248 error = vss_operate(op);
249 syslog(LOG_INFO, "VSS: op=%s: %s\n",
250 op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
251 error ? "failed" : "succeeded");
252
253 if (error) {
254 error = HV_E_FAIL;
255 syslog(LOG_ERR, "op=%d failed!", op);
256 syslog(LOG_ERR, "report it with these files:");
257 syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
258 }
259 break;
260 case VSS_OP_HOT_BACKUP:
261 syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
262 break;
263 default:
264 syslog(LOG_ERR, "Illegal op:%d\n", op);
265 }
266 vss_msg->error = error;
267 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
268 if (len != sizeof(struct hv_vss_msg)) {
269 syslog(LOG_ERR, "write failed; error: %d %s", errno,
270 strerror(errno));
271
272 if (op == VSS_OP_FREEZE)
273 vss_operate(VSS_OP_THAW);
274 }
275 }
276
277 close(vss_fd);
278 exit(0);
279}
280
