ASoC: rt274: Add fall-through annotations
[linux/fpc-iii.git] / tools / hv / hv_vss_daemon.c
blobb1330017276236b91ca2a5be84a3ce48dc07e4f9
1 /*
2 * An implementation of the host initiated guest snapshot for Hyper-V.
5 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
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.
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.
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 #include <stdbool.h>
40 #include <dirent.h>
42 /* Don't use syslog() in the function since that can cause write to disk */
43 static int vss_do_freeze(char *dir, unsigned int cmd)
45 int ret, fd = open(dir, O_RDONLY);
47 if (fd < 0)
48 return 1;
50 ret = ioctl(fd, cmd, 0);
53 * If a partition is mounted more than once, only the first
54 * FREEZE/THAW can succeed and the later ones will get
55 * EBUSY/EINVAL respectively: there could be 2 cases:
56 * 1) a user may mount the same partition to differnt directories
57 * by mistake or on purpose;
58 * 2) The subvolume of btrfs appears to have the same partition
59 * mounted more than once.
61 if (ret) {
62 if ((cmd == FIFREEZE && errno == EBUSY) ||
63 (cmd == FITHAW && errno == EINVAL)) {
64 close(fd);
65 return 0;
69 close(fd);
70 return !!ret;
73 static bool is_dev_loop(const char *blkname)
75 char *buffer;
76 DIR *dir;
77 struct dirent *entry;
78 bool ret = false;
80 buffer = malloc(PATH_MAX);
81 if (!buffer) {
82 syslog(LOG_ERR, "Can't allocate memory!");
83 exit(1);
86 snprintf(buffer, PATH_MAX, "%s/loop", blkname);
87 if (!access(buffer, R_OK | X_OK)) {
88 ret = true;
89 goto free_buffer;
90 } else if (errno != ENOENT) {
91 syslog(LOG_ERR, "Can't access: %s; error:%d %s!",
92 buffer, errno, strerror(errno));
95 snprintf(buffer, PATH_MAX, "%s/slaves", blkname);
96 dir = opendir(buffer);
97 if (!dir) {
98 if (errno != ENOENT)
99 syslog(LOG_ERR, "Can't opendir: %s; error:%d %s!",
100 buffer, errno, strerror(errno));
101 goto free_buffer;
104 while ((entry = readdir(dir)) != NULL) {
105 if (strcmp(entry->d_name, ".") == 0 ||
106 strcmp(entry->d_name, "..") == 0)
107 continue;
109 snprintf(buffer, PATH_MAX, "%s/slaves/%s", blkname,
110 entry->d_name);
111 if (is_dev_loop(buffer)) {
112 ret = true;
113 break;
116 closedir(dir);
117 free_buffer:
118 free(buffer);
119 return ret;
122 static int vss_operate(int operation)
124 char match[] = "/dev/";
125 FILE *mounts;
126 struct mntent *ent;
127 struct stat sb;
128 char errdir[1024] = {0};
129 char blkdir[23]; /* /sys/dev/block/XXX:XXX */
130 unsigned int cmd;
131 int error = 0, root_seen = 0, save_errno = 0;
133 switch (operation) {
134 case VSS_OP_FREEZE:
135 cmd = FIFREEZE;
136 break;
137 case VSS_OP_THAW:
138 cmd = FITHAW;
139 break;
140 default:
141 return -1;
144 mounts = setmntent("/proc/mounts", "r");
145 if (mounts == NULL)
146 return -1;
148 while ((ent = getmntent(mounts))) {
149 if (strncmp(ent->mnt_fsname, match, strlen(match)))
150 continue;
151 if (stat(ent->mnt_fsname, &sb)) {
152 syslog(LOG_ERR, "Can't stat: %s; error:%d %s!",
153 ent->mnt_fsname, errno, strerror(errno));
154 } else {
155 sprintf(blkdir, "/sys/dev/block/%d:%d",
156 major(sb.st_rdev), minor(sb.st_rdev));
157 if (is_dev_loop(blkdir))
158 continue;
160 if (hasmntopt(ent, MNTOPT_RO) != NULL)
161 continue;
162 if (strcmp(ent->mnt_type, "vfat") == 0)
163 continue;
164 if (strcmp(ent->mnt_dir, "/") == 0) {
165 root_seen = 1;
166 continue;
168 error |= vss_do_freeze(ent->mnt_dir, cmd);
169 if (error && operation == VSS_OP_FREEZE)
170 goto err;
173 endmntent(mounts);
175 if (root_seen) {
176 error |= vss_do_freeze("/", cmd);
177 if (error && operation == VSS_OP_FREEZE)
178 goto err;
181 goto out;
182 err:
183 save_errno = errno;
184 if (ent) {
185 strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
186 endmntent(mounts);
188 vss_operate(VSS_OP_THAW);
189 /* Call syslog after we thaw all filesystems */
190 if (ent)
191 syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
192 errdir, save_errno, strerror(save_errno));
193 else
194 syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
195 strerror(save_errno));
196 out:
197 return error;
200 void print_usage(char *argv[])
202 fprintf(stderr, "Usage: %s [options]\n"
203 "Options are:\n"
204 " -n, --no-daemon stay in foreground, don't daemonize\n"
205 " -h, --help print this help\n", argv[0]);
208 int main(int argc, char *argv[])
210 int vss_fd, len;
211 int error;
212 struct pollfd pfd;
213 int op;
214 struct hv_vss_msg vss_msg[1];
215 int daemonize = 1, long_index = 0, opt;
216 int in_handshake = 1;
217 __u32 kernel_modver;
219 static struct option long_options[] = {
220 {"help", no_argument, 0, 'h' },
221 {"no-daemon", no_argument, 0, 'n' },
222 {0, 0, 0, 0 }
225 while ((opt = getopt_long(argc, argv, "hn", long_options,
226 &long_index)) != -1) {
227 switch (opt) {
228 case 'n':
229 daemonize = 0;
230 break;
231 case 'h':
232 default:
233 print_usage(argv);
234 exit(EXIT_FAILURE);
238 if (daemonize && daemon(1, 0))
239 return 1;
241 openlog("Hyper-V VSS", 0, LOG_USER);
242 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
244 vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
245 if (vss_fd < 0) {
246 syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
247 errno, strerror(errno));
248 exit(EXIT_FAILURE);
251 * Register ourselves with the kernel.
253 vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
255 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
256 if (len < 0) {
257 syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
258 errno, strerror(errno));
259 close(vss_fd);
260 exit(EXIT_FAILURE);
263 pfd.fd = vss_fd;
265 while (1) {
266 pfd.events = POLLIN;
267 pfd.revents = 0;
269 if (poll(&pfd, 1, -1) < 0) {
270 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
271 if (errno == EINVAL) {
272 close(vss_fd);
273 exit(EXIT_FAILURE);
275 else
276 continue;
279 len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
281 if (in_handshake) {
282 if (len != sizeof(kernel_modver)) {
283 syslog(LOG_ERR, "invalid version negotiation");
284 exit(EXIT_FAILURE);
286 kernel_modver = *(__u32 *)vss_msg;
287 in_handshake = 0;
288 syslog(LOG_INFO, "VSS: kernel module version: %d",
289 kernel_modver);
290 continue;
293 if (len != sizeof(struct hv_vss_msg)) {
294 syslog(LOG_ERR, "read failed; error:%d %s",
295 errno, strerror(errno));
296 close(vss_fd);
297 return EXIT_FAILURE;
300 op = vss_msg->vss_hdr.operation;
301 error = HV_S_OK;
303 switch (op) {
304 case VSS_OP_FREEZE:
305 case VSS_OP_THAW:
306 error = vss_operate(op);
307 syslog(LOG_INFO, "VSS: op=%s: %s\n",
308 op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
309 error ? "failed" : "succeeded");
311 if (error) {
312 error = HV_E_FAIL;
313 syslog(LOG_ERR, "op=%d failed!", op);
314 syslog(LOG_ERR, "report it with these files:");
315 syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
317 break;
318 case VSS_OP_HOT_BACKUP:
319 syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
320 break;
321 default:
322 syslog(LOG_ERR, "Illegal op:%d\n", op);
324 vss_msg->error = error;
325 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
326 if (len != sizeof(struct hv_vss_msg)) {
327 syslog(LOG_ERR, "write failed; error: %d %s", errno,
328 strerror(errno));
330 if (op == VSS_OP_FREEZE)
331 vss_operate(VSS_OP_THAW);
335 close(vss_fd);
336 exit(0);