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lvm2/lib/device/dev-swap.c

86 lines
1.7 KiB
C

/*
* Copyright (C) 2009 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "metadata.h"
#include "xlate.h"
#include "filter.h"
#ifdef linux
#define MAX_PAGESIZE (64 * 1024)
#define SIGNATURE_SIZE 10
static int
_swap_detect_signature(const char *buf)
{
if (memcmp(buf, "SWAP-SPACE", 10) == 0 ||
memcmp(buf, "SWAPSPACE2", 10) == 0)
return 1;
if (memcmp(buf, "S1SUSPEND", 9) == 0 ||
memcmp(buf, "S2SUSPEND", 9) == 0 ||
memcmp(buf, "ULSUSPEND", 9) == 0 ||
memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0)
return 1;
return 0;
}
int dev_is_swap(struct device *dev, uint64_t *signature)
{
char buf[10];
uint64_t size;
int page, ret = 0;
if (!dev_get_size(dev, &size)) {
stack;
return -1;
}
if (!dev_open(dev)) {
stack;
return -1;
}
*signature = 0;
for (page = 0x1000; page <= MAX_PAGESIZE; page <<= 1) {
/*
* skip 32k pagesize since this does not seem to be supported
*/
if (page == 0x8000)
continue;
if (size < page)
break;
if (!dev_read(dev, page - SIGNATURE_SIZE,
SIGNATURE_SIZE, buf)) {
ret = -1;
break;
}
if (_swap_detect_signature(buf)) {
*signature = page - SIGNATURE_SIZE;
ret = 1;
break;
}
}
if (!dev_close(dev))
stack;
return ret;
}
#endif