michael@0: // Copyright (c) 2006, Google Inc.
michael@0: // All rights reserved.
michael@0: //
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: // notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: // copyright notice, this list of conditions and the following disclaimer
michael@0: // in the documentation and/or other materials provided with the
michael@0: // distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: // contributors may be used to endorse or promote products derived from
michael@0: // this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: #include "common/linux/guid_creator.h"
michael@0: 
michael@0: #include <assert.h>
michael@0: #include <pthread.h>
michael@0: #include <stdio.h>
michael@0: #include <stdlib.h>
michael@0: #include <time.h>
michael@0: #include <unistd.h>
michael@0: 
michael@0: //
michael@0: // GUIDGenerator
michael@0: //
michael@0: // This class is used to generate random GUID.
michael@0: // Currently use random number to generate a GUID since Linux has
michael@0: // no native GUID generator. This should be OK since we don't expect
michael@0: // crash to happen very offen.
michael@0: //
michael@0: class GUIDGenerator {
michael@0:  public:
michael@0:   static uint32_t BytesToUInt32(const uint8_t bytes[]) {
michael@0:     return ((uint32_t) bytes[0]
michael@0:             | ((uint32_t) bytes[1] << 8)
michael@0:             | ((uint32_t) bytes[2] << 16)
michael@0:             | ((uint32_t) bytes[3] << 24));
michael@0:   }
michael@0: 
michael@0:   static void UInt32ToBytes(uint8_t bytes[], uint32_t n) {
michael@0:     bytes[0] = n & 0xff;
michael@0:     bytes[1] = (n >> 8) & 0xff;
michael@0:     bytes[2] = (n >> 16) & 0xff;
michael@0:     bytes[3] = (n >> 24) & 0xff;
michael@0:   }
michael@0: 
michael@0:   static bool CreateGUID(GUID *guid) {
michael@0:     InitOnce();
michael@0:     guid->data1 = random();
michael@0:     guid->data2 = (uint16_t)(random());
michael@0:     guid->data3 = (uint16_t)(random());
michael@0:     UInt32ToBytes(&guid->data4[0], random());
michael@0:     UInt32ToBytes(&guid->data4[4], random());
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   static void InitOnce() {
michael@0:     pthread_once(&once_control, &InitOnceImpl);
michael@0:   }
michael@0: 
michael@0:   static void InitOnceImpl() {
michael@0:     srandom(time(NULL));
michael@0:   }
michael@0: 
michael@0:   static pthread_once_t once_control;
michael@0: };
michael@0: 
michael@0: pthread_once_t GUIDGenerator::once_control = PTHREAD_ONCE_INIT;
michael@0: 
michael@0: bool CreateGUID(GUID *guid) {
michael@0:   return GUIDGenerator::CreateGUID(guid);
michael@0: }
michael@0: 
michael@0: // Parse guid to string.
michael@0: bool GUIDToString(const GUID *guid, char *buf, int buf_len) {
michael@0:   // Should allow more space the the max length of GUID.
michael@0:   assert(buf_len > kGUIDStringLength);
michael@0:   int num = snprintf(buf, buf_len, kGUIDFormatString,
michael@0:                      guid->data1, guid->data2, guid->data3,
michael@0:                      GUIDGenerator::BytesToUInt32(&(guid->data4[0])),
michael@0:                      GUIDGenerator::BytesToUInt32(&(guid->data4[4])));
michael@0:   if (num != kGUIDStringLength)
michael@0:     return false;
michael@0: 
michael@0:   buf[num] = '\0';
michael@0:   return true;
michael@0: }