uuid.c

   1 /*
   2  * Copyright (C) 2010 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <string.h>
  18
  19 #ifdef USE_MINGW
  20 #include <winsock2.h>
  21 #else
  22 #include <arpa/inet.h>
  23 #endif
  24
  25 #include "ext4_utils.h"
  26 #include "sha1.h"
  27 #include "uuid.h"
  28
  29 /* Definition from RFC-4122 */
  30 struct uuid {
  31         u32 time_low;
  32         u16 time_mid;
  33         u16 time_hi_and_version;
  34         u8 clk_seq_hi_res;
  35         u8 clk_seq_low;
  36         u16 node0_1;
  37         u32 node2_5;
  38 };
  39
  40 static void sha1_hash(const char *namespace, const char *name,
  41         unsigned char sha1[SHA1_DIGEST_LENGTH])
  42 {
  43         SHA1_CTX ctx;
  44         SHA1Init(&ctx);
  45         SHA1Update(&ctx, (const u8*)namespace, strlen(namespace));
  46         SHA1Update(&ctx, (const u8*)name, strlen(name));
  47         SHA1Final(sha1, &ctx);
  48 }
  49
  50 void generate_uuid(const char *namespace, const char *name, u8 result[16])
  51 {
  52         unsigned char sha1[SHA1_DIGEST_LENGTH];
  53         struct uuid *uuid = (struct uuid *)result;
  54
  55         sha1_hash(namespace, name, (unsigned char*)sha1);
  56         memcpy(uuid, sha1, sizeof(struct uuid));
  57
  58         uuid->time_low = ntohl(uuid->time_low);
  59         uuid->time_mid = ntohs(uuid->time_mid);
  60         uuid->time_hi_and_version = ntohs(uuid->time_hi_and_version);
  61         uuid->time_hi_and_version &= 0x0FFF;
  62         uuid->time_hi_and_version |= (5 << 12);
  63         uuid->clk_seq_hi_res &= ~(1 << 6);
  64         uuid->clk_seq_hi_res |= 1 << 7;
  65 }