cdsa/cdsa_utilities/devrandom.cpp

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // devrandom - RNG operations based on /dev/random
  21 //
  22 #include <Security/devrandom.h>
  23 #include <Security/logging.h>
  24
  25 using namespace UnixPlusPlus;
  26
  27
  28 namespace Security {
  29
  30
  31 //
  32 // The common (shared) open file descriptor to /dev/random
  33 //
  34 ModuleNexus<DevRandomGenerator::Readonly> DevRandomGenerator::mReader;
  35 ModuleNexus<DevRandomGenerator::Writable> DevRandomGenerator::mWriter;
  36
  37
  38 //
  39 // In the current implementation, opening the file descriptor is deferred.
  40 //
  41 DevRandomGenerator::DevRandomGenerator(bool writable)
  42 {
  43 }
  44
  45
  46 //
  47 // Standard generate (directly from /dev/random)
  48 //
  49 void DevRandomGenerator::random(void *data, size_t length)
  50 {
  51     try {
  52                 size_t bytesRead = mReader().read(data, length);
  53                 if (bytesRead != length) {      // short read (shouldn't happen)
  54                         Syslog::error("DevRandomGenerator: wanted %ld got %ld bytes",
  55                                 length, bytesRead);
  56                         UnixError::throwMe(EIO);
  57                 }
  58         } catch(const UnixError &uerr) {
  59                 Syslog::error("DevRandomGenerator: error %d reading /dev/random",
  60                         uerr.error);
  61                 throw;
  62         }
  63 }
  64
  65
  66 //
  67 // If you opened for writing, you add entropy to the global pool here
  68 //
  69 void DevRandomGenerator::addEntropy(const void *data, size_t length)
  70 {
  71     if (mWriter().write(data, length) != length)
  72                 UnixError::throwMe(EIO);        // short write (shouldn't happen)
  73 }
  74
  75
  76 }       // end namespace Security