text: /*
   * 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 "dev-type.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 *offset_found)
  {
  	char buf[10];
  	uint64_t size;
  	unsigned page;
  	int ret = 0;
  
  	if (!dev_get_size(dev, &size)) {
  		stack;
  		return -1;
  	}
  
  	if (!dev_open_readonly(dev)) {
  		stack;
  		return -1;
  	}
  
  	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 >> SECTOR_SHIFT))
  			break;
  		if (!dev_read(dev, page - SIGNATURE_SIZE,
  			      SIGNATURE_SIZE, buf)) {
  			ret = -1;
  			break;
  		}
  		if (_swap_detect_signature(buf)) {
  			if (offset_found)
  				*offset_found = page - SIGNATURE_SIZE;
  			ret = 1;
  			break;
  		}
  	}
  
  	if (!dev_close(dev))
  		stack;
  
  	return ret;
  }
  
  #endif
  