util/uuid.c

   1 /*
   2  *  QEMU UUID functions
   3  *
   4  *  Copyright 2016 Red Hat, Inc.
   5  *
   6  *  Authors:
   7  *   Fam Zheng <famz@redhat.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include "qemu-common.h"
  18 #include "qemu/uuid.h"
  19 #include "qemu/bswap.h"
  20
  21 void qemu_uuid_generate(QemuUUID *uuid)
  22 {
  23     int i;
  24     uint32_t tmp[4];
  25
  26     QEMU_BUILD_BUG_ON(sizeof(QemuUUID) != 16);
  27
  28     for (i = 0; i < 4; ++i) {
  29         tmp[i] = g_random_int();
  30     }
  31     memcpy(uuid, tmp, sizeof(tmp));
  32     /* Set the two most significant bits (bits 6 and 7) of the
  33       clock_seq_hi_and_reserved to zero and one, respectively. */
  34     uuid->data[8] = (uuid->data[8] & 0x3f) | 0x80;
  35     /* Set the four most significant bits (bits 12 through 15) of the
  36       time_hi_and_version field to the 4-bit version number.
  37       */
  38     uuid->data[6] = (uuid->data[6] & 0xf) | 0x40;
  39 }
  40
  41 int qemu_uuid_is_null(const QemuUUID *uu)
  42 {
  43     static QemuUUID null_uuid;
  44     return qemu_uuid_is_equal(uu, &null_uuid);
  45 }
  46
  47 int qemu_uuid_is_equal(const QemuUUID *lhv, const QemuUUID *rhv)
  48 {
  49     return memcmp(lhv, rhv, sizeof(QemuUUID)) == 0;
  50 }
  51
  52 void qemu_uuid_unparse(const QemuUUID *uuid, char *out)
  53 {
  54     const unsigned char *uu = &uuid->data[0];
  55     snprintf(out, UUID_FMT_LEN + 1, UUID_FMT,
  56              uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7],
  57              uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]);
  58 }
  59
  60 char *qemu_uuid_unparse_strdup(const QemuUUID *uuid)
  61 {
  62     const unsigned char *uu = &uuid->data[0];
  63     return g_strdup_printf(UUID_FMT,
  64                            uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6],
  65                            uu[7], uu[8], uu[9], uu[10], uu[11], uu[12],
  66                            uu[13], uu[14], uu[15]);
  67 }
  68
  69 static bool qemu_uuid_is_valid(const char *str)
  70 {
  71     int i;
  72
  73     for (i = 0; i < strlen(str); i++) {
  74         const char c = str[i];
  75         if (i == 8 || i == 13 || i == 18 || i == 23) {
  76             if (str[i] != '-') {
  77                 return false;
  78             }
  79         } else {
  80             if ((c >= '0' && c <= '9') ||
  81                 (c >= 'A' && c <= 'F') ||
  82                 (c >= 'a' && c <= 'f')) {
  83                 continue;
  84             }
  85             return false;
  86         }
  87     }
  88     return i == 36;
  89 }
  90
  91 int qemu_uuid_parse(const char *str, QemuUUID *uuid)
  92 {
  93     unsigned char *uu = &uuid->data[0];
  94     int ret;
  95
  96     if (!qemu_uuid_is_valid(str)) {
  97         return -1;
  98     }
  99
 100     ret = sscanf(str, UUID_FMT, &uu[0], &uu[1], &uu[2], &uu[3],
 101                  &uu[4], &uu[5], &uu[6], &uu[7], &uu[8], &uu[9],
 102                  &uu[10], &uu[11], &uu[12], &uu[13], &uu[14],
 103                  &uu[15]);
 104
 105     if (ret != 16) {
 106         return -1;
 107     }
 108     return 0;
 109 }
 110
 111 /* Swap from UUID format endian (BE) to the opposite or vice versa.
 112  */
 113 QemuUUID qemu_uuid_bswap(QemuUUID uuid)
 114 {
 115     bswap32s(&uuid.fields.time_low);
 116     bswap16s(&uuid.fields.time_mid);
 117     bswap16s(&uuid.fields.time_high_and_version);
 118     return uuid;
 119 }