release/src-rt-6.x.4708/linux/linux-2.6.36/fs/xfs/support/uuid.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include <xfs.h>
  19
  20 /* IRIX interpretation of an uuid_t */
  21 typedef struct {
  22         __be32  uu_timelow;
  23         __be16  uu_timemid;
  24         __be16  uu_timehi;
  25         __be16  uu_clockseq;
  26         __be16  uu_node[3];
  27 } xfs_uu_t;
  28
  29 /*
  30  * uuid_getnodeuniq - obtain the node unique fields of a UUID.
  31  *
  32  * This is not in any way a standard or condoned UUID function;
  33  * it just something that's needed for user-level file handles.
  34  */
  35 void
  36 uuid_getnodeuniq(uuid_t *uuid, int fsid [2])
  37 {
  38         xfs_uu_t *uup = (xfs_uu_t *)uuid;
  39
  40         fsid[0] = (be16_to_cpu(uup->uu_clockseq) << 16) |
  41                    be16_to_cpu(uup->uu_timemid);
  42         fsid[1] = be32_to_cpu(uup->uu_timelow);
  43 }
  44
  45 int
  46 uuid_is_nil(uuid_t *uuid)
  47 {
  48         int     i;
  49         char    *cp = (char *)uuid;
  50
  51         if (uuid == NULL)
  52                 return 0;
  53         /* implied check of version number here... */
  54         for (i = 0; i < sizeof *uuid; i++)
  55                 if (*cp++) return 0;    /* not nil */
  56         return 1;       /* is nil */
  57 }
  58
  59 int
  60 uuid_equal(uuid_t *uuid1, uuid_t *uuid2)
  61 {
  62         return memcmp(uuid1, uuid2, sizeof(uuid_t)) ? 0 : 1;
  63 }