/*      $NetBSD: dev-swap.c,v 1.2 2009/12/02 01:53:25 haad Exp $        */

/*
* 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;

       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)) {
                       stack;
                       return -1;
               }
               if (_swap_detect_signature(buf)) {
                       *signature = page - SIGNATURE_SIZE;
                       break;
               }
       }

       if (!dev_close(dev))
               stack;

       if (*signature)
               return 1;

       return 0;
}

#else

#ifdef __NetBSD__
int dev_is_swap(struct device *dev, uint64_t *signature)
{
       return 0;
}
#endif

#endif