[deliverable/linux.git] / tools / hv / hv_vss_daemon.c

/*
 * 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 <sys/ioctl.h>
#include <linux/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <mntent.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <arpa/inet.h>
#include <linux/fs.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_do_freeze(char *dir, unsigned int cmd, char *fs_op)
{
	int ret, fd = open(dir, O_RDONLY);

	if (fd < 0)
		return 1;
	ret = ioctl(fd, cmd, 0);
	syslog(LOG_INFO, "VSS: %s of %s: %s\n", fs_op, dir, strerror(errno));
	close(fd);
	return !!ret;
}

static int vss_operate(int operation)
{
	char *fs_op;
	char match[] = "/dev/";
	FILE *mounts;
	struct mntent *ent;
	unsigned int cmd;
	int error = 0, root_seen = 0;

	switch (operation) {
	case VSS_OP_FREEZE:
		cmd = FIFREEZE;
		fs_op = "freeze";
		break;
	case VSS_OP_THAW:
		cmd = FITHAW;
		fs_op = "thaw";
		break;
	default:
		return -1;
	}

	mounts = setmntent("/proc/mounts", "r");
	if (mounts == NULL)
		return -1;

	while ((ent = getmntent(mounts))) {
		if (strncmp(ent->mnt_fsname, match, strlen(match)))
			continue;
		if (strcmp(ent->mnt_type, "iso9660") == 0)
			continue;
		if (strcmp(ent->mnt_dir, "/") == 0) {
			root_seen = 1;
			continue;
		}
		error |= vss_do_freeze(ent->mnt_dir, cmd, fs_op);
	}
	endmntent(mounts);

	if (root_seen) {
		error |= vss_do_freeze("/", cmd, fs_op);
	}

	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;

	if (daemon(1, 0))
		return 1;

	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) {
			syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
					addr.nl_pid, errno, strerror(errno));
			close(fd);
			return -1;
		}

		if (addr.nl_pid) {
			syslog(LOG_WARNING,
				"Received packet from untrusted pid:%u",
				addr.nl_pid);
			continue;
		}

		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);
		}
	}

}
Commit	Line	Data
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;
7b413b65 OH	74	fs_op = "freeze";
96dd86fa S	75	break;
96dd86fa S	76	case VSS_OP_THAW:
7b413b65 OH	77	cmd = FITHAW;
7b413b65 OH	78	fs_op = "thaw";
96dd86fa	79	break;
eb8905b8 OH	80	default:
eb8905b8 OH	81	return -1;
96dd86fa S	82	}
96dd86fa S	83
d3d1ee3a OH	84	mounts = setmntent("/proc/mounts", "r");
d3d1ee3a OH	85	if (mounts == NULL)
eb8905b8	86	return -1;
96dd86fa	87
0e272639	88	while ((ent = getmntent(mounts))) {
d3d1ee3a	89	if (strncmp(ent->mnt_fsname, match, strlen(match)))
96dd86fa	90	continue;
10b637b4 OH	91	if (strcmp(ent->mnt_type, "iso9660") == 0)
10b637b4 OH	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	}