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> | |
22 | #include <sys/socket.h> | |
23 | #include <sys/poll.h> | |
7b413b65 | 24 | #include <sys/ioctl.h> |
96dd86fa | 25 | #include <linux/types.h> |
7b413b65 | 26 | #include <fcntl.h> |
96dd86fa | 27 | #include <stdio.h> |
d3d1ee3a | 28 | #include <mntent.h> |
96dd86fa S |
29 | #include <stdlib.h> |
30 | #include <unistd.h> | |
31 | #include <string.h> | |
32 | #include <ctype.h> | |
33 | #include <errno.h> | |
34 | #include <arpa/inet.h> | |
7b413b65 | 35 | #include <linux/fs.h> |
96dd86fa S |
36 | #include <linux/connector.h> |
37 | #include <linux/hyperv.h> | |
38 | #include <linux/netlink.h> | |
39 | #include <syslog.h> | |
40 | ||
41 | static char vss_recv_buffer[4096]; | |
42 | static char vss_send_buffer[4096]; | |
43 | static struct sockaddr_nl addr; | |
44 | ||
45 | #ifndef SOL_NETLINK | |
46 | #define SOL_NETLINK 270 | |
47 | #endif | |
48 | ||
49 | ||
7b413b65 OH |
50 | static int vss_do_freeze(char *dir, unsigned int cmd, char *fs_op) |
51 | { | |
52 | int ret, fd = open(dir, O_RDONLY); | |
53 | ||
54 | if (fd < 0) | |
55 | return 1; | |
56 | ret = ioctl(fd, cmd, 0); | |
57 | syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno)); | |
58 | close(fd); | |
59 | return !!ret; | |
60 | } | |
61 | ||
96dd86fa S |
62 | static int vss_operate(int operation) |
63 | { | |
64 | char *fs_op; | |
d3d1ee3a OH |
65 | char match[] = "/dev/"; |
66 | FILE *mounts; | |
67 | struct mntent *ent; | |
7b413b65 | 68 | unsigned int cmd; |
d3d1ee3a | 69 | int error = 0, root_seen = 0; |
96dd86fa S |
70 | |
71 | switch (operation) { | |
72 | case VSS_OP_FREEZE: | |
7b413b65 OH |
73 | cmd = FIFREEZE; |
74 | fs_op = "freeze"; | |
96dd86fa S |
75 | break; |
76 | case VSS_OP_THAW: | |
7b413b65 OH |
77 | cmd = FITHAW; |
78 | fs_op = "thaw"; | |
96dd86fa | 79 | break; |
eb8905b8 OH |
80 | default: |
81 | return -1; | |
96dd86fa S |
82 | } |
83 | ||
d3d1ee3a OH |
84 | mounts = setmntent("/proc/mounts", "r"); |
85 | if (mounts == NULL) | |
eb8905b8 | 86 | return -1; |
96dd86fa | 87 | |
d3d1ee3a OH |
88 | while((ent = getmntent(mounts))) { |
89 | if (strncmp(ent->mnt_fsname, match, strlen(match))) | |
96dd86fa | 90 | continue; |
10b637b4 OH |
91 | if (strcmp(ent->mnt_type, "iso9660") == 0) |
92 | continue; | |
d3d1ee3a OH |
93 | if (strcmp(ent->mnt_dir, "/") == 0) { |
94 | root_seen = 1; | |
95 | continue; | |
96 | } | |
7b413b65 | 97 | error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op); |
96dd86fa | 98 | } |
d3d1ee3a | 99 | endmntent(mounts); |
96dd86fa | 100 | |
d3d1ee3a | 101 | if (root_seen) { |
7b413b65 | 102 | error |= vss_do_freeze("/", cmd, fs_op); |
d3d1ee3a | 103 | } |
96dd86fa S |
104 | |
105 | return error; | |
106 | } | |
107 | ||
108 | static int netlink_send(int fd, struct cn_msg *msg) | |
109 | { | |
110 | struct nlmsghdr *nlh; | |
111 | unsigned int size; | |
112 | struct msghdr message; | |
113 | char buffer[64]; | |
114 | struct iovec iov[2]; | |
115 | ||
116 | size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len); | |
117 | ||
118 | nlh = (struct nlmsghdr *)buffer; | |
119 | nlh->nlmsg_seq = 0; | |
120 | nlh->nlmsg_pid = getpid(); | |
121 | nlh->nlmsg_type = NLMSG_DONE; | |
122 | nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh)); | |
123 | nlh->nlmsg_flags = 0; | |
124 | ||
125 | iov[0].iov_base = nlh; | |
126 | iov[0].iov_len = sizeof(*nlh); | |
127 | ||
128 | iov[1].iov_base = msg; | |
129 | iov[1].iov_len = size; | |
130 | ||
131 | memset(&message, 0, sizeof(message)); | |
132 | message.msg_name = &addr; | |
133 | message.msg_namelen = sizeof(addr); | |
134 | message.msg_iov = iov; | |
135 | message.msg_iovlen = 2; | |
136 | ||
137 | return sendmsg(fd, &message, 0); | |
138 | } | |
139 | ||
140 | int main(void) | |
141 | { | |
142 | int fd, len, nl_group; | |
143 | int error; | |
144 | struct cn_msg *message; | |
145 | struct pollfd pfd; | |
146 | struct nlmsghdr *incoming_msg; | |
147 | struct cn_msg *incoming_cn_msg; | |
148 | int op; | |
149 | struct hv_vss_msg *vss_msg; | |
150 | ||
eb8905b8 OH |
151 | if (daemon(1, 0)) |
152 | return 1; | |
153 | ||
96dd86fa S |
154 | openlog("Hyper-V VSS", 0, LOG_USER); |
155 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); | |
156 | ||
157 | fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); | |
158 | if (fd < 0) { | |
159 | syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd); | |
160 | exit(EXIT_FAILURE); | |
161 | } | |
162 | addr.nl_family = AF_NETLINK; | |
163 | addr.nl_pad = 0; | |
164 | addr.nl_pid = 0; | |
165 | addr.nl_groups = 0; | |
166 | ||
167 | ||
168 | error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); | |
169 | if (error < 0) { | |
170 | syslog(LOG_ERR, "bind failed; error:%d", error); | |
171 | close(fd); | |
172 | exit(EXIT_FAILURE); | |
173 | } | |
174 | nl_group = CN_VSS_IDX; | |
175 | setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)); | |
176 | /* | |
177 | * Register ourselves with the kernel. | |
178 | */ | |
179 | message = (struct cn_msg *)vss_send_buffer; | |
180 | message->id.idx = CN_VSS_IDX; | |
181 | message->id.val = CN_VSS_VAL; | |
182 | message->ack = 0; | |
183 | vss_msg = (struct hv_vss_msg *)message->data; | |
184 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER; | |
185 | ||
186 | message->len = sizeof(struct hv_vss_msg); | |
187 | ||
188 | len = netlink_send(fd, message); | |
189 | if (len < 0) { | |
190 | syslog(LOG_ERR, "netlink_send failed; error:%d", len); | |
191 | close(fd); | |
192 | exit(EXIT_FAILURE); | |
193 | } | |
194 | ||
195 | pfd.fd = fd; | |
196 | ||
197 | while (1) { | |
198 | struct sockaddr *addr_p = (struct sockaddr *) &addr; | |
199 | socklen_t addr_l = sizeof(addr); | |
200 | pfd.events = POLLIN; | |
201 | pfd.revents = 0; | |
202 | poll(&pfd, 1, -1); | |
203 | ||
204 | len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0, | |
205 | addr_p, &addr_l); | |
206 | ||
5edf5ee4 | 207 | if (len < 0) { |
96dd86fa S |
208 | syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", |
209 | addr.nl_pid, errno, strerror(errno)); | |
210 | close(fd); | |
211 | return -1; | |
212 | } | |
213 | ||
5edf5ee4 | 214 | if (addr.nl_pid) { |
038336a5 S |
215 | syslog(LOG_WARNING, |
216 | "Received packet from untrusted pid:%u", | |
217 | addr.nl_pid); | |
5edf5ee4 OH |
218 | continue; |
219 | } | |
220 | ||
96dd86fa S |
221 | incoming_msg = (struct nlmsghdr *)vss_recv_buffer; |
222 | ||
223 | if (incoming_msg->nlmsg_type != NLMSG_DONE) | |
224 | continue; | |
225 | ||
226 | incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); | |
227 | vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; | |
228 | op = vss_msg->vss_hdr.operation; | |
229 | error = HV_S_OK; | |
230 | ||
231 | switch (op) { | |
232 | case VSS_OP_FREEZE: | |
233 | case VSS_OP_THAW: | |
234 | error = vss_operate(op); | |
235 | if (error) | |
236 | error = HV_E_FAIL; | |
237 | break; | |
238 | default: | |
239 | syslog(LOG_ERR, "Illegal op:%d\n", op); | |
240 | } | |
241 | vss_msg->error = error; | |
242 | len = netlink_send(fd, incoming_cn_msg); | |
243 | if (len < 0) { | |
244 | syslog(LOG_ERR, "net_link send failed; error:%d", len); | |
245 | exit(EXIT_FAILURE); | |
246 | } | |
247 | } | |
248 | ||
249 | } |