external/gpl2/lvm2/dist/lib/device/dev-swap.c

   1 /*      $NetBSD: dev-swap.c,v 1.1.1.1 2009/12/02 00:26:34 haad Exp $    */
   2
   3 /*
   4  * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
   5  *
   6  * This file is part of LVM2.
   7  *
   8  * This copyrighted material is made available to anyone wishing to use,
   9  * modify, copy, or redistribute it subject to the terms and conditions
  10  * of the GNU Lesser General Public License v.2.1.
  11  *
  12  * You should have received a copy of the GNU Lesser General Public License
  13  * along with this program; if not, write to the Free Software Foundation,
  14  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  15  */
  16
  17 #include "lib.h"
  18 #include "metadata.h"
  19 #include "xlate.h"
  20 #include "filter.h"
  21
  22 #ifdef linux
  23
  24 #define MAX_PAGESIZE    (64 * 1024)
  25 #define SIGNATURE_SIZE  10
  26
  27 static int
  28 _swap_detect_signature(const char *buf)
  29 {
  30         if (memcmp(buf, "SWAP-SPACE", 10) == 0 ||
  31             memcmp(buf, "SWAPSPACE2", 10) == 0)
  32                 return 1;
  33
  34         if (memcmp(buf, "S1SUSPEND", 9) == 0 ||
  35             memcmp(buf, "S2SUSPEND", 9) == 0 ||
  36             memcmp(buf, "ULSUSPEND", 9) == 0 ||
  37             memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0)
  38                 return 1;
  39
  40         return 0;
  41 }
  42
  43 int dev_is_swap(struct device *dev, uint64_t *signature)
  44 {
  45         char buf[10];
  46         uint64_t size;
  47         int page;
  48
  49         if (!dev_get_size(dev, &size)) {
  50                 stack;
  51                 return -1;
  52         }
  53
  54         if (!dev_open(dev)) {
  55                 stack;
  56                 return -1;
  57         }
  58
  59         *signature = 0;
  60
  61         for (page = 0x1000; page <= MAX_PAGESIZE; page <<= 1) {
  62                 /*
  63                  * skip 32k pagesize since this does not seem to be supported
  64                  */
  65                 if (page == 0x8000)
  66                         continue;
  67                 if (size < page)
  68                         break;
  69                 if (!dev_read(dev, page - SIGNATURE_SIZE,
  70                               SIGNATURE_SIZE, buf)) {
  71                         stack;
  72                         return -1;
  73                 }
  74                 if (_swap_detect_signature(buf)) {
  75                         *signature = page - SIGNATURE_SIZE;
  76                         break;
  77                 }
  78         }
  79
  80         if (!dev_close(dev))
  81                 stack;
  82
  83         if (*signature)
  84                 return 1;
  85
  86         return 0;
  87 }
  88
  89 #else
  90
  91 #ifdef __NetBSD__
  92 int dev_is_swap(struct device *dev, uint64_t *signature)
  93 {
  94         return 0;
  95 }
  96 #endif
  97
  98 #endif