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7b0ce3 |
/*
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7b0ce3 |
* An implementation of the host initiated guest snapshot for Hyper-V.
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7b0ce3 |
*
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7b0ce3 |
*
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7b0ce3 |
* Copyright (C) 2013, Microsoft, Inc.
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7b0ce3 |
* Author : K. Y. Srinivasan <kys@microsoft.com>
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7b0ce3 |
*
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7b0ce3 |
* This program is free software; you can redistribute it and/or modify it
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7b0ce3 |
* under the terms of the GNU General Public License version 2 as published
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7b0ce3 |
* by the Free Software Foundation.
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7b0ce3 |
*
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7b0ce3 |
* This program is distributed in the hope that it will be useful, but
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7b0ce3 |
* WITHOUT ANY WARRANTY; without even the implied warranty of
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7b0ce3 |
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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7b0ce3 |
* NON INFRINGEMENT. See the GNU General Public License for more
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7b0ce3 |
* details.
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7b0ce3 |
*
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7b0ce3 |
*/
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7b0ce3 |
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7b0ce3 |
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7b0ce3 |
#include <sys/types.h>
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7b0ce3 |
#include <sys/poll.h>
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7b0ce3 |
#include <sys/ioctl.h>
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820bc1 |
#include <sys/stat.h>
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820bc1 |
#include <sys/sysmacros.h>
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7b0ce3 |
#include <fcntl.h>
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7b0ce3 |
#include <stdio.h>
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7b0ce3 |
#include <mntent.h>
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7b0ce3 |
#include <stdlib.h>
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7b0ce3 |
#include <unistd.h>
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7b0ce3 |
#include <string.h>
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7b0ce3 |
#include <ctype.h>
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7b0ce3 |
#include <errno.h>
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7b0ce3 |
#include <linux/fs.h>
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820bc1 |
#include <linux/major.h>
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7b0ce3 |
#include <linux/hyperv.h>
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7b0ce3 |
#include <syslog.h>
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68a822 |
#include <getopt.h>
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7b0ce3 |
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68a822 |
/* Don't use syslog() in the function since that can cause write to disk */
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68a822 |
static int vss_do_freeze(char *dir, unsigned int cmd)
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7b0ce3 |
{
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7b0ce3 |
int ret, fd = open(dir, O_RDONLY);
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7b0ce3 |
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7b0ce3 |
if (fd < 0)
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7b0ce3 |
return 1;
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68a822 |
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7b0ce3 |
ret = ioctl(fd, cmd, 0);
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68a822 |
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68a822 |
/*
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68a822 |
* If a partition is mounted more than once, only the first
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68a822 |
* FREEZE/THAW can succeed and the later ones will get
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68a822 |
* EBUSY/EINVAL respectively: there could be 2 cases:
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68a822 |
* 1) a user may mount the same partition to differnt directories
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68a822 |
* by mistake or on purpose;
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68a822 |
* 2) The subvolume of btrfs appears to have the same partition
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68a822 |
* mounted more than once.
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68a822 |
*/
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68a822 |
if (ret) {
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68a822 |
if ((cmd == FIFREEZE && errno == EBUSY) ||
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68a822 |
(cmd == FITHAW && errno == EINVAL)) {
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68a822 |
close(fd);
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68a822 |
return 0;
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68a822 |
}
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68a822 |
}
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68a822 |
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7b0ce3 |
close(fd);
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7b0ce3 |
return !!ret;
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7b0ce3 |
}
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7b0ce3 |
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7b0ce3 |
static int vss_operate(int operation)
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7b0ce3 |
{
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7b0ce3 |
char match[] = "/dev/";
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7b0ce3 |
FILE *mounts;
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7b0ce3 |
struct mntent *ent;
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820bc1 |
struct stat sb;
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68a822 |
char errdir[1024] = {0};
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7b0ce3 |
unsigned int cmd;
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68a822 |
int error = 0, root_seen = 0, save_errno = 0;
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7b0ce3 |
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7b0ce3 |
switch (operation) {
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7b0ce3 |
case VSS_OP_FREEZE:
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7b0ce3 |
cmd = FIFREEZE;
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7b0ce3 |
break;
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7b0ce3 |
case VSS_OP_THAW:
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7b0ce3 |
cmd = FITHAW;
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7b0ce3 |
break;
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7b0ce3 |
default:
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7b0ce3 |
return -1;
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7b0ce3 |
}
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7b0ce3 |
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7b0ce3 |
mounts = setmntent("/proc/mounts", "r");
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7b0ce3 |
if (mounts == NULL)
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7b0ce3 |
return -1;
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7b0ce3 |
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7b0ce3 |
while ((ent = getmntent(mounts))) {
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7b0ce3 |
if (strncmp(ent->mnt_fsname, match, strlen(match)))
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7b0ce3 |
continue;
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820bc1 |
if (stat(ent->mnt_fsname, &sb) == -1)
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820bc1 |
continue;
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820bc1 |
if (S_ISBLK(sb.st_mode) && major(sb.st_rdev) == LOOP_MAJOR)
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820bc1 |
continue;
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68a822 |
if (hasmntopt(ent, MNTOPT_RO) != NULL)
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7b0ce3 |
continue;
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41f5a8 |
if (strcmp(ent->mnt_type, "vfat") == 0)
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41f5a8 |
continue;
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7b0ce3 |
if (strcmp(ent->mnt_dir, "/") == 0) {
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7b0ce3 |
root_seen = 1;
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7b0ce3 |
continue;
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7b0ce3 |
}
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68a822 |
error |= vss_do_freeze(ent->mnt_dir, cmd);
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68a822 |
if (error && operation == VSS_OP_FREEZE)
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68a822 |
goto err;
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7b0ce3 |
}
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68a822 |
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7b0ce3 |
endmntent(mounts);
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7b0ce3 |
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7b0ce3 |
if (root_seen) {
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68a822 |
error |= vss_do_freeze("/", cmd);
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68a822 |
if (error && operation == VSS_OP_FREEZE)
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68a822 |
goto err;
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7b0ce3 |
}
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7b0ce3 |
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68a822 |
goto out;
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68a822 |
err:
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68a822 |
save_errno = errno;
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68a822 |
if (ent) {
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68a822 |
strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
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68a822 |
endmntent(mounts);
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68a822 |
}
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68a822 |
vss_operate(VSS_OP_THAW);
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68a822 |
/* Call syslog after we thaw all filesystems */
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68a822 |
if (ent)
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68a822 |
syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
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68a822 |
errdir, save_errno, strerror(save_errno));
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68a822 |
else
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68a822 |
syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
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68a822 |
strerror(save_errno));
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68a822 |
out:
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7b0ce3 |
return error;
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7b0ce3 |
}
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7b0ce3 |
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68a822 |
void print_usage(char *argv[])
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68a822 |
{
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68a822 |
fprintf(stderr, "Usage: %s [options]\n"
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68a822 |
"Options are:\n"
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68a822 |
" -n, --no-daemon stay in foreground, don't daemonize\n"
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68a822 |
" -h, --help print this help\n", argv[0]);
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68a822 |
}
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68a822 |
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68a822 |
int main(int argc, char *argv[])
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7b0ce3 |
{
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1c9ae8 |
int vss_fd, len;
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7b0ce3 |
int error;
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7b0ce3 |
struct pollfd pfd;
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7b0ce3 |
int op;
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1c9ae8 |
struct hv_vss_msg vss_msg[1];
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68a822 |
int daemonize = 1, long_index = 0, opt;
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1c9ae8 |
int in_handshake = 1;
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1c9ae8 |
__u32 kernel_modver;
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68a822 |
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68a822 |
static struct option long_options[] = {
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68a822 |
{"help", no_argument, 0, 'h' },
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68a822 |
{"no-daemon", no_argument, 0, 'n' },
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68a822 |
{0, 0, 0, 0 }
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68a822 |
};
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68a822 |
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68a822 |
while ((opt = getopt_long(argc, argv, "hn", long_options,
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68a822 |
&long_index)) != -1) {
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68a822 |
switch (opt) {
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68a822 |
case 'n':
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68a822 |
daemonize = 0;
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68a822 |
break;
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68a822 |
case 'h':
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68a822 |
default:
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68a822 |
print_usage(argv);
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68a822 |
exit(EXIT_FAILURE);
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68a822 |
}
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68a822 |
}
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7b0ce3 |
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68a822 |
if (daemonize && daemon(1, 0))
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7b0ce3 |
return 1;
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7b0ce3 |
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7b0ce3 |
openlog("Hyper-V VSS", 0, LOG_USER);
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7b0ce3 |
syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
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7b0ce3 |
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1c9ae8 |
vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
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1c9ae8 |
if (vss_fd < 0) {
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1c9ae8 |
syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
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1c9ae8 |
errno, strerror(errno));
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7b0ce3 |
exit(EXIT_FAILURE);
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7b0ce3 |
}
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7b0ce3 |
/*
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7b0ce3 |
* Register ourselves with the kernel.
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7b0ce3 |
*/
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1c9ae8 |
vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
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7b0ce3 |
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1c9ae8 |
len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
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7b0ce3 |
if (len < 0) {
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1c9ae8 |
syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
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1c9ae8 |
errno, strerror(errno));
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1c9ae8 |
close(vss_fd);
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7b0ce3 |
exit(EXIT_FAILURE);
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7b0ce3 |
}
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7b0ce3 |
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1c9ae8 |
pfd.fd = vss_fd;
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7b0ce3 |
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7b0ce3 |
while (1) {
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7b0ce3 |
pfd.events = POLLIN;
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7b0ce3 |
pfd.revents = 0;
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7b0ce3 |
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7b0ce3 |
if (poll(&pfd, 1, -1) < 0) {
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7b0ce3 |
syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
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7b0ce3 |
if (errno == EINVAL) {
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1c9ae8 |
close(vss_fd);
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7b0ce3 |
exit(EXIT_FAILURE);
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7b0ce3 |
}
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7b0ce3 |
else
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7b0ce3 |
continue;
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7b0ce3 |
}
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7b0ce3 |
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1c9ae8 |
len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
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7b0ce3 |
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1c9ae8 |
if (in_handshake) {
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1c9ae8 |
if (len != sizeof(kernel_modver)) {
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1c9ae8 |
syslog(LOG_ERR, "invalid version negotiation");
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1c9ae8 |
exit(EXIT_FAILURE);
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1c9ae8 |
}
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1c9ae8 |
kernel_modver = *(__u32 *)vss_msg;
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1c9ae8 |
in_handshake = 0;
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1c9ae8 |
syslog(LOG_INFO, "VSS: kernel module version: %d",
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1c9ae8 |
kernel_modver);
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7b0ce3 |
continue;
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7b0ce3 |
}
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7b0ce3 |
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1c9ae8 |
if (len != sizeof(struct hv_vss_msg)) {
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1c9ae8 |
syslog(LOG_ERR, "read failed; error:%d %s",
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1c9ae8 |
errno, strerror(errno));
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1c9ae8 |
close(vss_fd);
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1c9ae8 |
return EXIT_FAILURE;
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1c9ae8 |
}
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7b0ce3 |
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7b0ce3 |
op = vss_msg->vss_hdr.operation;
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7b0ce3 |
error = HV_S_OK;
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7b0ce3 |
|
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7b0ce3 |
switch (op) {
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7b0ce3 |
case VSS_OP_FREEZE:
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7b0ce3 |
case VSS_OP_THAW:
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7b0ce3 |
error = vss_operate(op);
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68a822 |
syslog(LOG_INFO, "VSS: op=%s: %s\n",
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68a822 |
op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
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68a822 |
error ? "failed" : "succeeded");
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68a822 |
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68a822 |
if (error) {
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7b0ce3 |
error = HV_E_FAIL;
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68a822 |
syslog(LOG_ERR, "op=%d failed!", op);
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68a822 |
syslog(LOG_ERR, "report it with these files:");
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68a822 |
syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
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|
68a822 |
}
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7b0ce3 |
break;
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|
f22315 |
case VSS_OP_HOT_BACKUP:
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|
f22315 |
syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
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|
f22315 |
break;
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7b0ce3 |
default:
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7b0ce3 |
syslog(LOG_ERR, "Illegal op:%d\n", op);
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|
7b0ce3 |
}
|
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7b0ce3 |
vss_msg->error = error;
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|
1c9ae8 |
len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
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|
1c9ae8 |
if (len != sizeof(struct hv_vss_msg)) {
|
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1c9ae8 |
syslog(LOG_ERR, "write failed; error: %d %s", errno,
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1c9ae8 |
strerror(errno));
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820bc1 |
|
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|
820bc1 |
if (op == VSS_OP_FREEZE)
|
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|
820bc1 |
vss_operate(VSS_OP_THAW);
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|
7b0ce3 |
}
|
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|
7b0ce3 |
}
|
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|
7b0ce3 |
|
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|
1c9ae8 |
close(vss_fd);
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|
1c9ae8 |
exit(0);
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|
7b0ce3 |
}
|