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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 <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
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
52
53
54
55
56
57
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
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
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}
281
