diff options
Diffstat (limited to 'tools/hv/hv_vss_daemon.c')
| -rw-r--r-- | tools/hv/hv_vss_daemon.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c new file mode 100644 index 000000000000..95269952aa92 --- /dev/null +++ b/tools/hv/hv_vss_daemon.c @@ -0,0 +1,220 @@ +/* + * An implementation of the host initiated guest snapshot for Hyper-V. + * + * + * Copyright (C) 2013, Microsoft, Inc. + * Author : K. Y. Srinivasan <kys@microsoft.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + */ + + +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/poll.h> +#include <linux/types.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <ctype.h> +#include <errno.h> +#include <arpa/inet.h> +#include <linux/connector.h> +#include <linux/hyperv.h> +#include <linux/netlink.h> +#include <syslog.h> + +static char vss_recv_buffer[4096]; +static char vss_send_buffer[4096]; +static struct sockaddr_nl addr; + +#ifndef SOL_NETLINK +#define SOL_NETLINK 270 +#endif + + +static int vss_operate(int operation) +{ + char *fs_op; + char cmd[512]; + char buf[512]; + FILE *file; + char *p; + char *x; + int error; + + switch (operation) { + case VSS_OP_FREEZE: + fs_op = "-f "; + break; + case VSS_OP_THAW: + fs_op = "-u "; + break; + } + + file = popen("mount | awk '/^\/dev\// { print $3}'", "r"); + if (file == NULL) + return; + + while ((p = fgets(buf, sizeof(buf), file)) != NULL) { + x = strchr(p, '\n'); + *x = '\0'; + if (!strncmp(p, "/", sizeof("/"))) + continue; + + sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, p); + syslog(LOG_INFO, "VSS cmd is %s\n", cmd); + error = system(cmd); + } + pclose(file); + + sprintf(cmd, "%s %s %s", "fsfreeze ", fs_op, "/"); + syslog(LOG_INFO, "VSS cmd is %s\n", cmd); + error = system(cmd); + + return error; +} + +static int netlink_send(int fd, struct cn_msg *msg) +{ + struct nlmsghdr *nlh; + unsigned int size; + struct msghdr message; + char buffer[64]; + struct iovec iov[2]; + + size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len); + + nlh = (struct nlmsghdr *)buffer; + nlh->nlmsg_seq = 0; + nlh->nlmsg_pid = getpid(); + nlh->nlmsg_type = NLMSG_DONE; + nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh)); + nlh->nlmsg_flags = 0; + + iov[0].iov_base = nlh; + iov[0].iov_len = sizeof(*nlh); + + iov[1].iov_base = msg; + iov[1].iov_len = size; + + memset(&message, 0, sizeof(message)); + message.msg_name = &addr; + message.msg_namelen = sizeof(addr); + message.msg_iov = iov; + message.msg_iovlen = 2; + + return sendmsg(fd, &message, 0); +} + +int main(void) +{ + int fd, len, nl_group; + int error; + struct cn_msg *message; + struct pollfd pfd; + struct nlmsghdr *incoming_msg; + struct cn_msg *incoming_cn_msg; + int op; + struct hv_vss_msg *vss_msg; + + daemon(1, 0); + openlog("Hyper-V VSS", 0, LOG_USER); + syslog(LOG_INFO, "VSS starting; pid is:%d", getpid()); + + fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR); + if (fd < 0) { + syslog(LOG_ERR, "netlink socket creation failed; error:%d", fd); + exit(EXIT_FAILURE); + } + addr.nl_family = AF_NETLINK; + addr.nl_pad = 0; + addr.nl_pid = 0; + addr.nl_groups = 0; + + + error = bind(fd, (struct sockaddr *)&addr, sizeof(addr)); + if (error < 0) { + syslog(LOG_ERR, "bind failed; error:%d", error); + close(fd); + exit(EXIT_FAILURE); + } + nl_group = CN_VSS_IDX; + setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)); + /* + * Register ourselves with the kernel. + */ + message = (struct cn_msg *)vss_send_buffer; + message->id.idx = CN_VSS_IDX; + message->id.val = CN_VSS_VAL; + message->ack = 0; + vss_msg = (struct hv_vss_msg *)message->data; + vss_msg->vss_hdr.operation = VSS_OP_REGISTER; + + message->len = sizeof(struct hv_vss_msg); + + len = netlink_send(fd, message); + if (len < 0) { + syslog(LOG_ERR, "netlink_send failed; error:%d", len); + close(fd); + exit(EXIT_FAILURE); + } + + pfd.fd = fd; + + while (1) { + struct sockaddr *addr_p = (struct sockaddr *) &addr; + socklen_t addr_l = sizeof(addr); + pfd.events = POLLIN; + pfd.revents = 0; + poll(&pfd, 1, -1); + + len = recvfrom(fd, vss_recv_buffer, sizeof(vss_recv_buffer), 0, + addr_p, &addr_l); + + if (len < 0 || addr.nl_pid) { + syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", + addr.nl_pid, errno, strerror(errno)); + close(fd); + return -1; + } + + incoming_msg = (struct nlmsghdr *)vss_recv_buffer; + + if (incoming_msg->nlmsg_type != NLMSG_DONE) + continue; + + incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg); + vss_msg = (struct hv_vss_msg *)incoming_cn_msg->data; + op = vss_msg->vss_hdr.operation; + error = HV_S_OK; + + switch (op) { + case VSS_OP_FREEZE: + case VSS_OP_THAW: + error = vss_operate(op); + if (error) + error = HV_E_FAIL; + break; + default: + syslog(LOG_ERR, "Illegal op:%d\n", op); + } + vss_msg->error = error; + len = netlink_send(fd, incoming_cn_msg); + if (len < 0) { + syslog(LOG_ERR, "net_link send failed; error:%d", len); + exit(EXIT_FAILURE); + } + } + +} |