usr/src/lib/libuuid/common/uuid_misc.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  * Copyright (c) 2015, Joyent, Inc.
  26  */
  27
  28 /*
  29  * The copyright in this file is taken from the original Leach
  30  * & Salz UUID specification, from which this implementation
  31  * is derived.
  32  */
  33
  34 /*
  35  * Copyright (c) 1990- 1993, 1996 Open Software Foundation, Inc.
  36  * Copyright (c) 1989 by Hewlett-Packard Company, Palo Alto, Ca. &
  37  * Digital Equipment Corporation, Maynard, Mass.  Copyright (c) 1998
  38  * Microsoft.  To anyone who acknowledges that this file is provided
  39  * "AS IS" without any express or implied warranty: permission to use,
  40  * copy, modify, and distribute this file for any purpose is hereby
  41  * granted without fee, provided that the above copyright notices and
  42  * this notice appears in all source code copies, and that none of the
  43  * names of Open Software Foundation, Inc., Hewlett-Packard Company,
  44  * or Digital Equipment Corporation be used in advertising or
  45  * publicity pertaining to distribution of the software without
  46  * specific, written prior permission.  Neither Open Software
  47  * Foundation, Inc., Hewlett-Packard Company, Microsoft, nor Digital
  48  * Equipment Corporation makes any representations about the
  49  * suitability of this software for any purpose.
  50  */
  51
  52 #include <uuid/uuid.h>
  53 #include <stdlib.h>
  54 #include <strings.h>
  55 #include "uuid_misc.h"
  56
  57 #define UUCMP(u1, u2)           if (u1 != u2) return ((u1 < u2) ? -1 : 1)
  58 #define UUIDS_PER_TOD_CALL      10      /* tv_usec is multiplied by 10 */
  59
  60 void            struct_to_string(uuid_t, struct uuid *);
  61 void            string_to_struct(struct uuid *, uuid_t);
  62 void            get_system_time(uuid_time_t *);
  63
  64 /*
  65  * Name:        get_current_time
  66  *
  67  * Description: get-current_time -- get time as 60 bit 100ns ticks
  68  *              since the beginning of unix time.
  69  *              Compensate for the fact that real clock resolution is
  70  *              less than 100ns.
  71  *
  72  * Returns:     None.
  73  *
  74  */
  75 void
  76 get_current_time(uuid_time_t *timestamp)
  77 {
  78         uuid_time_t             time_now;
  79         static uuid_time_t      time_last = 0;
  80         static uint16_t         uuids_this_tick = 0;
  81         int                     done;
  82
  83         done = 0;
  84         while (!done) {
  85                 get_system_time(&time_now);
  86
  87                 /*
  88                  * if clock reading changed since last UUID generated...
  89                  */
  90                 if (time_last != time_now) {
  91                         /*
  92                          * reset count of uuids generated with
  93                          * this clock reading
  94                          */
  95                         uuids_this_tick = 0;
  96                         done = 1;
  97                 } else {
  98                         uuids_this_tick++;
  99                         if (uuids_this_tick < UUIDS_PER_TOD_CALL)
 100                                 done = 1;
 101                 }
 102                 /*
 103                  * too many UUIDs for this gettimeofday call; spin
 104                  */
 105         }
 106         time_last = time_now;
 107         /*
 108          * add the count of uuids to low order bits of the clock reading
 109          */
 110         *timestamp = time_now + uuids_this_tick;
 111 }
 112
 113 /*
 114  * Name:        get_random
 115  *
 116  * Description: Gets a random number.
 117  *
 118  * Returns:     nbytes of random information.
 119  *
 120  */
 121 uint16_t
 122 get_random(void)
 123 {
 124         return (arc4random_uniform(UINT16_MAX));
 125 }
 126
 127 /*
 128  * Name:        uuid_compare
 129  *
 130  * Description: Compares 2 uuid strings
 131  *
 132  * Returns:     -1 if u1 < u2, 1 if u1 > u2 and 0 if both are equal
 133  */
 134 int
 135 uuid_compare(uuid_t uu1, uuid_t uu2)
 136 {
 137
 138         struct uuid     uuid1, uuid2;
 139
 140         string_to_struct(&uuid1, uu1);
 141         string_to_struct(&uuid2, uu2);
 142         UUCMP(uuid1.time_low, uuid2.time_low);
 143         UUCMP(uuid1.time_mid, uuid2.time_mid);
 144         UUCMP(uuid1.time_hi_and_version, uuid2.time_hi_and_version);
 145         UUCMP(uuid1.clock_seq_hi_and_reserved, uuid2.clock_seq_hi_and_reserved);
 146         UUCMP(uuid1.clock_seq_low, uuid2.clock_seq_low);
 147         return (memcmp(uuid1.node_addr, uuid2.node_addr, 6));
 148 }
 149
 150 /*
 151  * Name:        get_system_time
 152  *
 153  * Description: system dependent call to get the current system time.
 154  *              Returned as 100ns ticks since Oct 15, 1582, but
 155  *              resolution may be less than 100ns.
 156  *
 157  * Returns:     None
 158  */
 159 void
 160 get_system_time(uuid_time_t *uuid_time)
 161 {
 162         struct timeval tp;
 163
 164         (void) gettimeofday(&tp, (struct timezone *)0);
 165
 166         /*
 167          * Offset between UUID formatted times and Unix formatted times.
 168          * UUID UTC base time is October 15, 1582.
 169          * Unix base time is January 1, 1970.
 170          */
 171         *uuid_time = (uint64_t)tp.tv_sec * 10000000;
 172         *uuid_time += tp.tv_usec * 10;
 173         *uuid_time += 0x01B21DD213814000ULL;
 174 }