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/uuid.h" 18 #include "qemu/bswap.h" 19 20 void qemu_uuid_generate(QemuUUID *uuid) 21 { 22 int i; 23 uint32_t tmp[4]; 24 25 QEMU_BUILD_BUG_ON(sizeof(QemuUUID) != 16); 26 27 for (i = 0; i < 4; ++i) { 28 tmp[i] = g_random_int(); 29 } 30 memcpy(uuid, tmp, sizeof(tmp)); 31 /* Set the two most significant bits (bits 6 and 7) of the 32 clock_seq_hi_and_reserved to zero and one, respectively. */ 33 uuid->data[8] = (uuid->data[8] & 0x3f) | 0x80; 34 /* Set the four most significant bits (bits 12 through 15) of the 35 time_hi_and_version field to the 4-bit version number. 36 */ 37 uuid->data[6] = (uuid->data[6] & 0xf) | 0x40; 38 } 39 40 int qemu_uuid_is_null(const QemuUUID *uu) 41 { 42 static QemuUUID null_uuid; 43 return qemu_uuid_is_equal(uu, &null_uuid); 44 } 45 46 int qemu_uuid_is_equal(const QemuUUID *lhv, const QemuUUID *rhv) 47 { 48 return memcmp(lhv, rhv, sizeof(QemuUUID)) == 0; 49 } 50 51 void qemu_uuid_unparse(const QemuUUID *uuid, char *out) 52 { 53 const unsigned char *uu = &uuid->data[0]; 54 snprintf(out, UUID_STR_LEN, UUID_FMT, 55 uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], uu[7], 56 uu[8], uu[9], uu[10], uu[11], uu[12], uu[13], uu[14], uu[15]); 57 } 58 59 char *qemu_uuid_unparse_strdup(const QemuUUID *uuid) 60 { 61 const unsigned char *uu = &uuid->data[0]; 62 return g_strdup_printf(UUID_FMT, 63 uu[0], uu[1], uu[2], uu[3], uu[4], uu[5], uu[6], 64 uu[7], uu[8], uu[9], uu[10], uu[11], uu[12], 65 uu[13], uu[14], uu[15]); 66 } 67 68 static bool qemu_uuid_is_valid(const char *str) 69 { 70 int i; 71 72 for (i = 0; i < strlen(str); i++) { 73 const char c = str[i]; 74 if (i == 8 || i == 13 || i == 18 || i == 23) { 75 if (str[i] != '-') { 76 return false; 77 } 78 } else { 79 if ((c >= '0' && c <= '9') || 80 (c >= 'A' && c <= 'F') || 81 (c >= 'a' && c <= 'f')) { 82 continue; 83 } 84 return false; 85 } 86 } 87 return i == 36; 88 } 89 90 int qemu_uuid_parse(const char *str, QemuUUID *uuid) 91 { 92 unsigned char *uu = &uuid->data[0]; 93 int ret; 94 95 if (!qemu_uuid_is_valid(str)) { 96 return -1; 97 } 98 99 ret = sscanf(str, UUID_FMT, &uu[0], &uu[1], &uu[2], &uu[3], 100 &uu[4], &uu[5], &uu[6], &uu[7], &uu[8], &uu[9], 101 &uu[10], &uu[11], &uu[12], &uu[13], &uu[14], 102 &uu[15]); 103 104 if (ret != 16) { 105 return -1; 106 } 107 return 0; 108 } 109 110 /* Swap from UUID format endian (BE) to the opposite or vice versa. 111 */ 112 QemuUUID qemu_uuid_bswap(QemuUUID uuid) 113 { 114 bswap32s(&uuid.fields.time_low); 115 bswap16s(&uuid.fields.time_mid); 116 bswap16s(&uuid.fields.time_high_and_version); 117 return uuid; 118 } 119 120 /* djb2 hash algorithm */ 121 uint32_t qemu_uuid_hash(const void *uuid) 122 { 123 QemuUUID *qid = (QemuUUID *) uuid; 124 uint32_t h = 5381; 125 int i; 126 127 for (i = 0; i < ARRAY_SIZE(qid->data); i++) { 128 h = (h << 5) + h + qid->data[i]; 129 } 130 131 return h; 132 } 133