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      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 }
     66