linux/tools/hv/hv_vss_daemon.c
K. Y. Srinivasan f33b215549 Tools: hv: vssdaemon: Ignore VFAT mounts during the Freeze operation
If the guest has a FAT file system mounted, skip it during the FREEZE
operation. With this change we can support host initiated backup of
the guest even when the guest may have FAT file systems mounted.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-15 11:53:39 -08:00

268 lines
5.9 KiB
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 <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 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_type, "vfat") == 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 = { .nlmsg_type = NLMSG_DONE };
unsigned int size;
struct msghdr message;
struct iovec iov[2];
size = sizeof(struct cn_msg) + msg->len;
nlh.nlmsg_pid = getpid();
nlh.nlmsg_len = NLMSG_LENGTH(size);
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;
char *vss_recv_buffer;
size_t vss_recv_buffer_len;
if (daemon(1, 0))
return 1;
openlog("Hyper-V VSS", 0, LOG_USER);
syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
vss_recv_buffer_len = NLMSG_LENGTH(0) + sizeof(struct cn_msg) + sizeof(struct hv_vss_msg);
vss_recv_buffer = calloc(1, vss_recv_buffer_len);
if (!vss_recv_buffer) {
syslog(LOG_ERR, "Failed to allocate netlink buffers");
exit(EXIT_FAILURE);
}
fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
if (fd < 0) {
syslog(LOG_ERR, "netlink socket creation failed; error:%d %s",
errno, strerror(errno));
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 %s", errno, strerror(errno));
close(fd);
exit(EXIT_FAILURE);
}
nl_group = CN_VSS_IDX;
if (setsockopt(fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &nl_group, sizeof(nl_group)) < 0) {
syslog(LOG_ERR, "setsockopt failed; error:%d %s", errno, strerror(errno));
close(fd);
exit(EXIT_FAILURE);
}
/*
* Register ourselves with the kernel.
*/
message = (struct cn_msg *)vss_recv_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 %s", errno, strerror(errno));
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;
if (poll(&pfd, 1, -1) < 0) {
syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
if (errno == EINVAL) {
close(fd);
exit(EXIT_FAILURE);
}
else
continue;
}
len = recvfrom(fd, vss_recv_buffer, vss_recv_buffer_len, 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 %s",
errno, strerror(errno));
exit(EXIT_FAILURE);
}
}
}