K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 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> |
| 24 | #include <linux/types.h> |
| 25 | #include <stdio.h> |
| 26 | #include <stdlib.h> |
| 27 | #include <unistd.h> |
| 28 | #include <string.h> |
| 29 | #include <ctype.h> |
| 30 | #include <errno.h> |
| 31 | #include <arpa/inet.h> |
| 32 | #include <linux/connector.h> |
| 33 | #include <linux/hyperv.h> |
| 34 | #include <linux/netlink.h> |
| 35 | #include <syslog.h> |
| 36 | |
| 37 | static char vss_recv_buffer[4096]; |
| 38 | static char vss_send_buffer[4096]; |
| 39 | static struct sockaddr_nl addr; |
| 40 | |
| 41 | #ifndef SOL_NETLINK |
| 42 | #define SOL_NETLINK 270 |
| 43 | #endif |
| 44 | |
| 45 | |
| 46 | static int vss_operate(int operation) |
| 47 | { |
| 48 | char *fs_op; |
| 49 | char cmd[512]; |
| 50 | char buf[512]; |
| 51 | FILE *file; |
| 52 | char *p; |
| 53 | char *x; |
Olaf Hering | eb8905b | 2013-04-24 07:48:48 -0700 | [diff] [blame^] | 54 | int error = 0; |
K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 55 | |
| 56 | switch (operation) { |
| 57 | case VSS_OP_FREEZE: |
| 58 | fs_op = "-f "; |
| 59 | break; |
| 60 | case VSS_OP_THAW: |
| 61 | fs_op = "-u "; |
| 62 | break; |
Olaf Hering | eb8905b | 2013-04-24 07:48:48 -0700 | [diff] [blame^] | 63 | default: |
| 64 | return -1; |
K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 65 | } |
| 66 | |
Olaf Hering | eb8905b | 2013-04-24 07:48:48 -0700 | [diff] [blame^] | 67 | file = popen("mount | awk '/^\\/dev\\// { print $3}'", "r"); |
K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 68 | if (file == NULL) |
Olaf Hering | eb8905b | 2013-04-24 07:48:48 -0700 | [diff] [blame^] | 69 | return -1; |
K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 70 | |
| 71 | while ((p = fgets(buf, sizeof(buf), file)) != NULL) { |
| 72 | x = strchr(p, '\n'); |
| 73 | *x = '\0'; |
| 74 | if (!strncmp(p, "/", sizeof("/"))) |
| 75 | continue; |
| 76 | |
| 77 | sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, p); |
| 78 | syslog(LOG_INFO, "VSS cmd is %s\n", cmd); |
| 79 | error = system(cmd); |
| 80 | } |
| 81 | pclose(file); |
| 82 | |
| 83 | sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, "/"); |
| 84 | syslog(LOG_INFO, "VSS cmd is %s\n", cmd); |
| 85 | error = system(cmd); |
| 86 | |
| 87 | return error; |
| 88 | } |
| 89 | |
| 90 | static int netlink_send(int fd, struct cn_msg *msg) |
| 91 | { |
| 92 | struct nlmsghdr *nlh; |
| 93 | unsigned int size; |
| 94 | struct msghdr message; |
| 95 | char buffer[64]; |
| 96 | struct iovec iov[2]; |
| 97 | |
| 98 | size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len); |
| 99 | |
| 100 | nlh = (struct nlmsghdr *)buffer; |
| 101 | nlh->nlmsg_seq = 0; |
| 102 | nlh->nlmsg_pid = getpid(); |
| 103 | nlh->nlmsg_type = NLMSG_DONE; |
| 104 | nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh)); |
| 105 | nlh->nlmsg_flags = 0; |
| 106 | |
| 107 | iov[0].iov_base = nlh; |
| 108 | iov[0].iov_len = sizeof(*nlh); |
| 109 | |
| 110 | iov[1].iov_base = msg; |
| 111 | iov[1].iov_len = size; |
| 112 | |
| 113 | memset(&message, 0, sizeof(message)); |
| 114 | message.msg_name = &addr; |
| 115 | message.msg_namelen = sizeof(addr); |
| 116 | message.msg_iov = iov; |
| 117 | message.msg_iovlen = 2; |
| 118 | |
| 119 | return sendmsg(fd, &message, 0); |
| 120 | } |
| 121 | |
| 122 | int main(void) |
| 123 | { |
| 124 | int fd, len, nl_group; |
| 125 | int error; |
| 126 | struct cn_msg *message; |
| 127 | struct pollfd pfd; |
| 128 | struct nlmsghdr *incoming_msg; |
| 129 | struct cn_msg *incoming_cn_msg; |
| 130 | int op; |
| 131 | struct hv_vss_msg *vss_msg; |
| 132 | |
Olaf Hering | eb8905b | 2013-04-24 07:48:48 -0700 | [diff] [blame^] | 133 | if (daemon(1, 0)) |
| 134 | return 1; |
| 135 | |
K. Y. Srinivasan | 96dd86f | 2013-03-15 12:30:06 -0700 | [diff] [blame] | 136 | openlog("Hyper-V VSS", 0, LOG_USER); |
| 137 | syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); |
| 138 | |
| 139 | fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); |
| 140 | if (fd < 0) { |
| 141 | syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd); |
| 142 | exit(EXIT_FAILURE); |
| 143 | } |
| 144 | addr.nl_family = AF_NETLINK; |
| 145 | addr.nl_pad = 0; |
| 146 | addr.nl_pid = 0; |
| 147 | addr.nl_groups = 0; |
| 148 | |
| 149 | |
| 150 | error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); |
| 151 | if (error < 0) { |
| 152 | syslog(LOG_ERR, "bind failed; error:%d", error); |
| 153 | close(fd); |
| 154 | exit(EXIT_FAILURE); |
| 155 | } |
| 156 | nl_group = CN_VSS_IDX; |
| 157 | setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)); |
| 158 | /* |
| 159 | * Register ourselves with the kernel. |
| 160 | */ |
| 161 | message = (struct cn_msg *)vss_send_buffer; |
| 162 | message->id.idx = CN_VSS_IDX; |
| 163 | message->id.val = CN_VSS_VAL; |
| 164 | message->ack = 0; |
| 165 | vss_msg = (struct hv_vss_msg *)message->data; |
| 166 | vss_msg->vss_hdr.operation = VSS_OP_REGISTER; |
| 167 | |
| 168 | message->len = sizeof(struct hv_vss_msg); |
| 169 | |
| 170 | len = netlink_send(fd, message); |
| 171 | if (len < 0) { |
| 172 | syslog(LOG_ERR, "netlink_send failed; error:%d", len); |
| 173 | close(fd); |
| 174 | exit(EXIT_FAILURE); |
| 175 | } |
| 176 | |
| 177 | pfd.fd = fd; |
| 178 | |
| 179 | while (1) { |
| 180 | struct sockaddr *addr_p = (struct sockaddr *) &addr; |
| 181 | socklen_t addr_l = sizeof(addr); |
| 182 | pfd.events = POLLIN; |
| 183 | pfd.revents = 0; |
| 184 | poll(&pfd, 1, -1); |
| 185 | |
| 186 | len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0, |
| 187 | addr_p, &addr_l); |
| 188 | |
| 189 | if (len < 0 || addr.nl_pid) { |
| 190 | syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", |
| 191 | addr.nl_pid, errno, strerror(errno)); |
| 192 | close(fd); |
| 193 | return -1; |
| 194 | } |
| 195 | |
| 196 | incoming_msg = (struct nlmsghdr *)vss_recv_buffer; |
| 197 | |
| 198 | if (incoming_msg->nlmsg_type != NLMSG_DONE) |
| 199 | continue; |
| 200 | |
| 201 | incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); |
| 202 | vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; |
| 203 | op = vss_msg->vss_hdr.operation; |
| 204 | error = HV_S_OK; |
| 205 | |
| 206 | switch (op) { |
| 207 | case VSS_OP_FREEZE: |
| 208 | case VSS_OP_THAW: |
| 209 | error = vss_operate(op); |
| 210 | if (error) |
| 211 | error = HV_E_FAIL; |
| 212 | break; |
| 213 | default: |
| 214 | syslog(LOG_ERR, "Illegal op:%d\n", op); |
| 215 | } |
| 216 | vss_msg->error = error; |
| 217 | len = netlink_send(fd, incoming_cn_msg); |
| 218 | if (len < 0) { |
| 219 | syslog(LOG_ERR, "net_link send failed; error:%d", len); |
| 220 | exit(EXIT_FAILURE); |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | } |