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K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -07001/*
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>
Olaf Hering7b413b62013-04-24 07:48:52 -070024#include <sys/ioctl.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070025#include <linux/types.h>
Olaf Hering7b413b62013-04-24 07:48:52 -070026#include <fcntl.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070027#include <stdio.h>
Olaf Heringd3d1ee32013-04-24 07:48:51 -070028#include <mntent.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070029#include <stdlib.h>
30#include <unistd.h>
31#include <string.h>
32#include <ctype.h>
33#include <errno.h>
34#include <arpa/inet.h>
Olaf Hering7b413b62013-04-24 07:48:52 -070035#include <linux/fs.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070036#include <linux/connector.h>
37#include <linux/hyperv.h>
38#include <linux/netlink.h>
39#include <syslog.h>
40
41static char vss_recv_buffer[4096];
42static char vss_send_buffer[4096];
43static struct sockaddr_nl addr;
44
45#ifndef SOL_NETLINK
46#define SOL_NETLINK 270
47#endif
48
49
Olaf Hering7b413b62013-04-24 07:48:52 -070050static 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
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070062static int vss_operate(int operation)
63{
64 char *fs_op;
Olaf Heringd3d1ee32013-04-24 07:48:51 -070065 char match[] = "/dev/";
66 FILE *mounts;
67 struct mntent *ent;
Olaf Hering7b413b62013-04-24 07:48:52 -070068 unsigned int cmd;
Olaf Heringd3d1ee32013-04-24 07:48:51 -070069 int error = 0, root_seen = 0;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070070
71 switch (operation) {
72 case VSS_OP_FREEZE:
Olaf Hering7b413b62013-04-24 07:48:52 -070073 cmd = FIFREEZE;
74 fs_op = "freeze";
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070075 break;
76 case VSS_OP_THAW:
Olaf Hering7b413b62013-04-24 07:48:52 -070077 cmd = FITHAW;
78 fs_op = "thaw";
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070079 break;
Olaf Heringeb8905b2013-04-24 07:48:48 -070080 default:
81 return -1;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070082 }
83
Olaf Heringd3d1ee32013-04-24 07:48:51 -070084 mounts = setmntent("/proc/mounts", "r");
85 if (mounts == NULL)
Olaf Heringeb8905b2013-04-24 07:48:48 -070086 return -1;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070087
K. Y. Srinivasan0e272632013-04-24 07:48:54 -070088 while ((ent = getmntent(mounts))) {
Olaf Heringd3d1ee32013-04-24 07:48:51 -070089 if (strncmp(ent->mnt_fsname, match, strlen(match)))
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070090 continue;
Olaf Hering10b637b2013-04-24 07:48:53 -070091 if (strcmp(ent->mnt_type, "iso9660") == 0)
92 continue;
Olaf Heringd3d1ee32013-04-24 07:48:51 -070093 if (strcmp(ent->mnt_dir, "/") == 0) {
94 root_seen = 1;
95 continue;
96 }
Olaf Hering7b413b62013-04-24 07:48:52 -070097 error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070098 }
Olaf Heringd3d1ee32013-04-24 07:48:51 -070099 endmntent(mounts);
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700100
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700101 if (root_seen) {
Olaf Hering7b413b62013-04-24 07:48:52 -0700102 error |= vss_do_freeze("/", cmd, fs_op);
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700103 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700104
105 return error;
106}
107
108static 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
140int 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
Olaf Heringeb8905b2013-04-24 07:48:48 -0700151 if (daemon(1, 0))
152 return 1;
153
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700154 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) {
Tomas Hozza5c289262013-06-27 13:52:47 +0200159 syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
160 errno, strerror(errno));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700161 exit(EXIT_FAILURE);
162 }
163 addr.nl_family = AF_NETLINK;
164 addr.nl_pad = 0;
165 addr.nl_pid = 0;
166 addr.nl_groups = 0;
167
168
169 error = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
170 if (error < 0) {
Tomas Hozza5c289262013-06-27 13:52:47 +0200171 syslog(LOG_ERR, "bind failed; error:%d %s", errno, strerror(errno));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700172 close(fd);
173 exit(EXIT_FAILURE);
174 }
175 nl_group = CN_VSS_IDX;
Tomas Hozzad12e1462013-06-27 13:52:48 +0200176 if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
177 syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
178 close(fd);
179 exit(EXIT_FAILURE);
180 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700181 /*
182 * Register ourselves with the kernel.
183 */
184 message = (struct cn_msg *)vss_send_buffer;
185 message->id.idx = CN_VSS_IDX;
186 message->id.val = CN_VSS_VAL;
187 message->ack = 0;
188 vss_msg = (struct hv_vss_msg *)message->data;
189 vss_msg->vss_hdr.operation = VSS_OP_REGISTER;
190
191 message->len = sizeof(struct hv_vss_msg);
192
193 len = netlink_send(fd, message);
194 if (len < 0) {
Tomas Hozza5c289262013-06-27 13:52:47 +0200195 syslog(LOG_ERR, "netlink_send failed; error:%d %s", errno, strerror(errno));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700196 close(fd);
197 exit(EXIT_FAILURE);
198 }
199
200 pfd.fd = fd;
201
202 while (1) {
203 struct sockaddr *addr_p = (struct sockaddr *) &addr;
204 socklen_t addr_l = sizeof(addr);
205 pfd.events = POLLIN;
206 pfd.revents = 0;
Tomas Hozza9561d472013-06-27 13:52:49 +0200207
208 if (poll(&pfd, 1, -1) < 0) {
209 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
210 if (errno == EINVAL) {
211 close(fd);
212 exit(EXIT_FAILURE);
213 }
214 else
215 continue;
216 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700217
218 len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0,
219 addr_p, &addr_l);
220
Olaf Hering5edf5ee2013-04-24 07:48:49 -0700221 if (len < 0) {
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700222 syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
223 addr.nl_pid, errno, strerror(errno));
224 close(fd);
225 return -1;
226 }
227
Olaf Hering5edf5ee2013-04-24 07:48:49 -0700228 if (addr.nl_pid) {
K. Y. Srinivasan038336a2013-04-24 07:48:50 -0700229 syslog(LOG_WARNING,
230 "Received packet from untrusted pid:%u",
231 addr.nl_pid);
Olaf Hering5edf5ee2013-04-24 07:48:49 -0700232 continue;
233 }
234
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700235 incoming_msg = (struct nlmsghdr *)vss_recv_buffer;
236
237 if (incoming_msg->nlmsg_type != NLMSG_DONE)
238 continue;
239
240 incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
241 vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data;
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 if (error)
250 error = HV_E_FAIL;
251 break;
252 default:
253 syslog(LOG_ERR, "Illegal op:%d\n", op);
254 }
255 vss_msg->error = error;
256 len = netlink_send(fd, incoming_cn_msg);
257 if (len < 0) {
Tomas Hozza5c289262013-06-27 13:52:47 +0200258 syslog(LOG_ERR, "net_link send failed; error:%d %s",
259 errno, strerror(errno));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700260 exit(EXIT_FAILURE);
261 }
262 }
263
264}