As-gui Sources / file revision

 //

 //  OSSP asgui - Accounting system graphical user interface

 //  Copyright (c) 2002-2009 The OSSP Project (http://www.ossp.org/)

 //  Copyright (c) 2002-2009 Ralf S. Engelschall <rse@engelschall.com>

 //  Copyright (c) 2002-2009 Michael Schloh von Bennewitz <michael@schloh.com>

 //  Copyright (c) 2002-2009 Cable & Wireless Telecommunications Services GmbH

 //

 //  This file is part of OSSP asgui, an accounting system graphical user

 //  interface which can be found at http://asgui.europalab.com/.

 //

 //  Permission to use, copy, modify, and distribute this software for

 //  any purpose with or without fee is hereby granted, provided that

 //  the above copyright notice and this permission notice appear in all

 //  copies.

 //

 //  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

 //  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 //  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 //  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR

 //  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 //  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 //  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

 //  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 //  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

 //  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

 //  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 //  SUCH DAMAGE.

 //

 //  as_rand.cpp: ISO C++ implementation

 //

 #include <fcntl.h>

 #include <cerrno>

 #include "as_rand.h"

 #if HAVE_UNISTD_H

 #include <unistd.h>

 #endif // HAVE_UNISTD_H

 #if HAVE_STDLIB_H

 #include <stdlib.h>

 #endif // HAVE_STDLIB_H

 #if TIME_WITH_SYS_TIME

 #include <sys/time.h>

 #include <time.h>

 #else

 #if HAVE_SYS_TIME_H

 #include <sys/time.h>

 #else

 #include <time.h>

 #endif // HAVE_SYS_TIME_H

 #endif // TIME_WITH_SYS_TIME

 namespace AS {

 // Constructor

 Rand::Rand(void)

 {

     this->nFd = -4; // Object fresh status

     this->openDevice();   // Open the random device

 //    if (this->nFd < 0)

 //        throw Genexcept("Could not open /dev/urandom or /dev/random.");

 }

 // Destructor

 Rand::~Rand(void)

 {

     this->closeDevice();  // Close the random device

     this->nFd = -4; // Return this object to its fresh status

 }

 //

 // Rand::openDevice(void)

 // Open the random device associated with this object

 //

 void Rand::openDevice(void)

 {

     struct timeval Time;

     if (this->nFd == -4) {  // -4 indicates a fresh object

         gettimeofday(&Time, 0);

         this->nFd = open("/dev/urandom", O_RDONLY);

         if (this->nFd == -1)

             this->nFd = open("/dev/random", O_RDONLY | O_NONBLOCK);

         srand((getpid() << 16) ^ getuid() ^ Time.tv_sec ^ Time.tv_usec); // Seed

     }

     // Improve randomness by stirring in entropy

     gettimeofday(&Time, 0);

     for (int nIter = (Time.tv_sec ^ Time.tv_usec) & 0x1F; nIter > 0; nIter--)

         rand();

 }

 //

 // Rand::closeDevice(void)

 // Close the random device associated with this object

 //

 void Rand::closeDevice(void)

 {

     if (this->nFd >= 0)

         close(this->nFd);

 }

 //

 // Rand::genData(void *pvBuf, int nBytes)

 // Generate a series of random data from the system

 // standard random devices /dev/[u|s]random

 //

 void Rand::genData(void *pBuf, int nBytes)

 {

     int nRead = 0;

     int nLost = 0;

     char *szOut = (char *)pBuf;

     if (this->nFd >= 0) {

         while (nBytes > 0) {

             nRead = read(this->nFd, szOut, nBytes);

             if ((nRead < 0) && ((errno == EINTR) || (errno == EAGAIN)))

                 continue;

             if (nRead <= 0) {

                 if (nLost++ == 8)

                     break;

                 continue;

             }

             nBytes -= nRead;

             szOut += nRead;

             nLost = 0;

         }

     }

     // For systems with no /dev/random, we do the next best thing

     for (int nIter = 0;  nIter< nBytes; nIter++)

         *szOut++ = rand() & 0xFF;

 }

 } // namespace AS