Commit | Line | Data |
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96dd86fa S |
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> | |
96dd86fa | 22 | #include <sys/poll.h> |
7b413b65 | 23 | #include <sys/ioctl.h> |
7b413b65 | 24 | #include <fcntl.h> |
96dd86fa | 25 | #include <stdio.h> |
d3d1ee3a | 26 | #include <mntent.h> |
96dd86fa S |
27 | #include <stdlib.h> |
28 | #include <unistd.h> | |
29 | #include <string.h> | |
30 | #include <ctype.h> | |
31 | #include <errno.h> | |
7b413b65 | 32 | #include <linux/fs.h> |
96dd86fa | 33 | #include <linux/hyperv.h> |
96dd86fa | 34 | #include <syslog.h> |
170f4bea | 35 | #include <getopt.h> |
96dd86fa | 36 | |
4f689190 DC |
37 | /* Don't use syslog() in the function since that can cause write to disk */ |
38 | static int vss_do_freeze(char *dir, unsigned int cmd) | |
7b413b65 OH |
39 | { |
40 | int ret, fd = open(dir, O_RDONLY); | |
41 | ||
42 | if (fd < 0) | |
43 | return 1; | |
4f689190 | 44 | |
7b413b65 | 45 | ret = ioctl(fd, cmd, 0); |
4f689190 DC |
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 | ||
7b413b65 OH |
64 | close(fd); |
65 | return !!ret; | |
66 | } | |
67 | ||
96dd86fa S |
68 | static int vss_operate(int operation) |
69 | { | |
d3d1ee3a OH |
70 | char match[] = "/dev/"; |
71 | FILE *mounts; | |
72 | struct mntent *ent; | |
4ce50e94 | 73 | char errdir[1024] = {0}; |
7b413b65 | 74 | unsigned int cmd; |
7a401744 | 75 | int error = 0, root_seen = 0, save_errno = 0; |
96dd86fa S |
76 | |
77 | switch (operation) { | |
78 | case VSS_OP_FREEZE: | |
7b413b65 | 79 | cmd = FIFREEZE; |
96dd86fa S |
80 | break; |
81 | case VSS_OP_THAW: | |
7b413b65 | 82 | cmd = FITHAW; |
96dd86fa | 83 | break; |
eb8905b8 OH |
84 | default: |
85 | return -1; | |
96dd86fa S |
86 | } |
87 | ||
d3d1ee3a OH |
88 | mounts = setmntent("/proc/mounts", "r"); |
89 | if (mounts == NULL) | |
eb8905b8 | 90 | return -1; |
96dd86fa | 91 | |
0e272639 | 92 | while ((ent = getmntent(mounts))) { |
d3d1ee3a | 93 | if (strncmp(ent->mnt_fsname, match, strlen(match))) |
96dd86fa | 94 | continue; |
9e5db05a | 95 | if (hasmntopt(ent, MNTOPT_RO) != NULL) |
10b637b4 | 96 | continue; |
f33b2155 S |
97 | if (strcmp(ent->mnt_type, "vfat") == 0) |
98 | continue; | |
d3d1ee3a OH |
99 | if (strcmp(ent->mnt_dir, "/") == 0) { |
100 | root_seen = 1; | |
101 | continue; | |
102 | } | |
4f689190 DC |
103 | error |= vss_do_freeze(ent->mnt_dir, cmd); |
104 | if (error && operation == VSS_OP_FREEZE) | |
105 | goto err; | |
96dd86fa | 106 | } |
96dd86fa | 107 | |
4ce50e94 VC |
108 | endmntent(mounts); |
109 | ||
d3d1ee3a | 110 | if (root_seen) { |
4f689190 DC |
111 | error |= vss_do_freeze("/", cmd); |
112 | if (error && operation == VSS_OP_FREEZE) | |
113 | goto err; | |
d3d1ee3a | 114 | } |
96dd86fa | 115 | |
7a401744 | 116 | goto out; |
4f689190 | 117 | err: |
7a401744 | 118 | save_errno = errno; |
4ce50e94 VC |
119 | if (ent) { |
120 | strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1); | |
121 | endmntent(mounts); | |
122 | } | |
4f689190 | 123 | vss_operate(VSS_OP_THAW); |
7a401744 VK |
124 | /* Call syslog after we thaw all filesystems */ |
125 | if (ent) | |
126 | syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s", | |
4ce50e94 | 127 | errdir, save_errno, strerror(save_errno)); |
7a401744 VK |
128 | else |
129 | syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno, | |
130 | strerror(save_errno)); | |
131 | out: | |
96dd86fa S |
132 | return error; |
133 | } | |
134 | ||
170f4bea VK |
135 | void 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 | ||
143 | int main(int argc, char *argv[]) | |
96dd86fa | 144 | { |
f5722b9b | 145 | int vss_fd, len; |
96dd86fa | 146 | int error; |
96dd86fa | 147 | struct pollfd pfd; |
96dd86fa | 148 | int op; |
f5722b9b | 149 | struct hv_vss_msg vss_msg[1]; |
170f4bea VK |
150 | int daemonize = 1, long_index = 0, opt; |
151 | ||
152 | static struct option long_options[] = { | |
153 | {"help", no_argument, 0, 'h' }, | |
154 | {"no-daemon", no_argument, 0, 'n' }, | |
155 | {0, 0, 0, 0 } | |
156 | }; | |
157 | ||
158 | while ((opt = getopt_long(argc, argv, "hn", long_options, | |
159 | &long_index)) != -1) { | |
160 | switch (opt) { | |
161 | case 'n': | |
162 | daemonize = 0; | |
163 | break; | |
164 | case 'h': | |
165 | default: | |
166 | print_usage(argv); | |
167 | exit(EXIT_FAILURE); | |
168 | } | |
169 | } | |
96dd86fa | 170 | |
170f4bea | 171 | if (daemonize && daemon(1, 0)) |
eb8905b8 OH |
172 | return 1; |
173 | ||
96dd86fa S |
174 | openlog("Hyper-V VSS", 0, LOG_USER); |
175 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); | |
176 | ||
f5722b9b VK |
177 | vss_fd = open("/dev/vmbus/hv_vss", O_RDWR); |
178 | if (vss_fd < 0) { | |
179 | syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s", | |
180 | errno, strerror(errno)); | |
d12e1469 TH |
181 | exit(EXIT_FAILURE); |
182 | } | |
96dd86fa S |
183 | /* |
184 | * Register ourselves with the kernel. | |
185 | */ | |
f5722b9b | 186 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER1; |
96dd86fa | 187 | |
f5722b9b | 188 | len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg)); |
96dd86fa | 189 | if (len < 0) { |
f5722b9b VK |
190 | syslog(LOG_ERR, "registration to kernel failed; error: %d %s", |
191 | errno, strerror(errno)); | |
192 | close(vss_fd); | |
96dd86fa S |
193 | exit(EXIT_FAILURE); |
194 | } | |
195 | ||
f5722b9b | 196 | pfd.fd = vss_fd; |
96dd86fa S |
197 | |
198 | while (1) { | |
96dd86fa S |
199 | pfd.events = POLLIN; |
200 | pfd.revents = 0; | |
9561d479 TH |
201 | |
202 | if (poll(&pfd, 1, -1) < 0) { | |
203 | syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno)); | |
204 | if (errno == EINVAL) { | |
f5722b9b | 205 | close(vss_fd); |
9561d479 TH |
206 | exit(EXIT_FAILURE); |
207 | } | |
208 | else | |
209 | continue; | |
210 | } | |
96dd86fa | 211 | |
f5722b9b | 212 | len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg)); |
96dd86fa | 213 | |
f5722b9b VK |
214 | if (len != sizeof(struct hv_vss_msg)) { |
215 | syslog(LOG_ERR, "read failed; error:%d %s", | |
216 | errno, strerror(errno)); | |
217 | close(vss_fd); | |
218 | return EXIT_FAILURE; | |
5edf5ee4 OH |
219 | } |
220 | ||
96dd86fa S |
221 | op = vss_msg->vss_hdr.operation; |
222 | error = HV_S_OK; | |
223 | ||
224 | switch (op) { | |
225 | case VSS_OP_FREEZE: | |
226 | case VSS_OP_THAW: | |
227 | error = vss_operate(op); | |
4f689190 DC |
228 | syslog(LOG_INFO, "VSS: op=%s: %s\n", |
229 | op == VSS_OP_FREEZE ? "FREEZE" : "THAW", | |
230 | error ? "failed" : "succeeded"); | |
231 | ||
232 | if (error) { | |
96dd86fa | 233 | error = HV_E_FAIL; |
4f689190 DC |
234 | syslog(LOG_ERR, "op=%d failed!", op); |
235 | syslog(LOG_ERR, "report it with these files:"); | |
236 | syslog(LOG_ERR, "/etc/fstab and /proc/mounts"); | |
237 | } | |
96dd86fa S |
238 | break; |
239 | default: | |
240 | syslog(LOG_ERR, "Illegal op:%d\n", op); | |
241 | } | |
242 | vss_msg->error = error; | |
f5722b9b VK |
243 | len = write(vss_fd, &error, sizeof(struct hv_vss_msg)); |
244 | if (len != sizeof(struct hv_vss_msg)) { | |
245 | syslog(LOG_ERR, "write failed; error: %d %s", errno, | |
246 | strerror(errno)); | |
96dd86fa S |
247 | exit(EXIT_FAILURE); |
248 | } | |
249 | } | |
250 | ||
f5722b9b VK |
251 | close(vss_fd); |
252 | exit(0); | |
96dd86fa | 253 | } |