Line data    Source code

       1             : /*
       2             :     Mosh: the mobile shell
       3             :     Copyright 2012 Keith Winstein
       4             : 
       5             :     This program is free software: you can redistribute it and/or modify
       6             :     it under the terms of the GNU General Public License as published by
       7             :     the Free Software Foundation, either version 3 of the License, or
       8             :     (at your option) any later version.
       9             : 
      10             :     This program is distributed in the hope that it will be useful,
      11             :     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13             :     GNU General Public License for more details.
      14             : 
      15             :     You should have received a copy of the GNU General Public License
      16             :     along with this program.  If not, see <http://www.gnu.org/licenses/>.
      17             : 
      18             :     In addition, as a special exception, the copyright holders give
      19             :     permission to link the code of portions of this program with the
      20             :     OpenSSL library under certain conditions as described in each
      21             :     individual source file, and distribute linked combinations including
      22             :     the two.
      23             : 
      24             :     You must obey the GNU General Public License in all respects for all
      25             :     of the code used other than OpenSSL. If you modify file(s) with this
      26             :     exception, you may extend this exception to your version of the
      27             :     file(s), but you are not obligated to do so. If you do not wish to do
      28             :     so, delete this exception statement from your version. If you delete
      29             :     this exception statement from all source files in the program, then
      30             :     also delete it here.
      31             : */
      32             : 
      33             : #ifndef PRNG_HPP
      34             : #define PRNG_HPP
      35             : 
      36             : #include <string>
      37             : #include <stdint.h>
      38             : #include <fstream>
      39             : 
      40             : #include "crypto.h"
      41             : 
      42             : /* Read random bytes from /dev/urandom.
      43             : 
      44             :    We rely on stdio buffering for efficiency. */
      45             : 
      46             : static const char rdev[] = "/dev/urandom";
      47             : 
      48             : using namespace Crypto;
      49             : 
      50         624 : class PRNG {
      51             :  private:
      52             :   std::ifstream randfile;
      53             : 
      54             :   /* unimplemented to satisfy -Weffc++ */
      55             :   PRNG( const PRNG & );
      56             :   PRNG & operator=( const PRNG & );
      57             : 
      58             :  public:
      59        1524 :   PRNG() : randfile( rdev, std::ifstream::in | std::ifstream::binary ) {}
      60             : 
      61      381256 :   void fill( void *dest, size_t size ) {
      62      381256 :     if ( 0 == size ) {
      63             :       return;
      64             :     }
      65             : 
      66      380895 :     randfile.read( static_cast<char *>( dest ), size );
      67      380895 :     if ( !randfile ) {
      68           0 :       throw CryptoException( "Could not read from " + std::string( rdev ) );
      69             :     }
      70             :   }
      71             : 
      72       40785 :   uint8_t uint8() {
      73       40785 :     uint8_t x;
      74       40785 :     fill( &x, 1 );
      75       40785 :     return x;
      76             :   }
      77             : 
      78       37489 :   uint32_t uint32() {
      79       37489 :     uint32_t x;
      80       37489 :     fill( &x, 4 );
      81       37489 :     return x;
      82             :   }
      83             : 
      84         128 :   uint64_t uint64() {
      85         128 :     uint64_t x;
      86         128 :     fill( &x, 8 );
      87         128 :     return x;
      88             :   }
      89             : };
      90             : 
      91             : #endif