LXR qemu/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
  21void 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
  41int qemu_uuid_is_null(const QemuUUID *uu)
  42{
  43    static QemuUUID null_uuid;
  44    return memcmp(uu, &null_uuid, sizeof(QemuUUID)) == 0;
  45}
  46
  47void qemu_uuid_unparse(const QemuUUID *uuid, char *out)
  48{
  49    const unsigned char *uu = &uuid->data[0];
  50    snprintf(out, UUID_FMT_LEN + 1, UUID_FMT,
  51             uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7],
  52             uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]);
  53}
  54
  55char *qemu_uuid_unparse_strdup(const QemuUUID *uuid)
  56{
  57    const unsigned char *uu = &uuid->data[0];
  58    return g_strdup_printf(UUID_FMT,
  59                           uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6],
  60                           uu[7], uu[8], uu[9], uu[10], uu[11], uu[12],
  61                           uu[13], uu[14], uu[15]);
  62}
  63
  64static bool qemu_uuid_is_valid(const char *str)
  65{
  66    int i;
  67
  68    for (i = 0; i < strlen(str); i++) {
  69        const char c = str[i];
  70        if (i == 8 || i == 13 || i == 18 || i == 23) {
  71            if (str[i] != '-') {
  72                return false;
  73            }
  74        } else {
  75            if ((c >= '0' && c <= '9') ||
  76                (c >= 'A' && c <= 'F') ||
  77                (c >= 'a' && c <= 'f')) {
  78                continue;
  79            }
  80            return false;
  81        }
  82    }
  83    return i == 36;
  84}
  85
  86int qemu_uuid_parse(const char *str, QemuUUID *uuid)
  87{
  88    unsigned char *uu = &uuid->data[0];
  89    int ret;
  90
  91    if (!qemu_uuid_is_valid(str)) {
  92        return -1;
  93    }
  94
  95    ret = sscanf(str, UUID_FMT, &uu[0], &uu[1], &uu[2], &uu[3],
  96                 &uu[4], &uu[5], &uu[6], &uu[7], &uu[8], &uu[9],
  97                 &uu[10], &uu[11], &uu[12], &uu[13], &uu[14],
  98                 &uu[15]);
  99
 100    if (ret != 16) {
 101        return -1;
 102    }
 103    return 0;
 104}
 105
 106/* Swap from UUID format endian (BE) to the opposite or vice versa.
 107 */
 108void qemu_uuid_bswap(QemuUUID *uuid)
 109{
 110    assert(QEMU_PTR_IS_ALIGNED(uuid, sizeof(uint32_t)));
 111    bswap32s(&uuid->fields.time_low);
 112    bswap16s(&uuid->fields.time_mid);
 113    bswap16s(&uuid->fields.time_high_and_version);
 114}
 115