michael@1: //
michael@1: //  OSSP asgui - Accounting system graphical user interface
michael@1: //  Copyright (c) 2002-2004 The OSSP Project (http://www.ossp.org/)
michael@1: //  Copyright (c) 2002-2004 Ralf S. Engelschall <rse@engelschall.com>
michael@1: //  Copyright (c) 2002-2004 Michael Schloh von Bennewitz <michael@schloh.com>
michael@1: //  Copyright (c) 2002-2004 Cable & Wireless Telecommunications Services GmbH
michael@1: //
michael@1: //  This file is part of OSSP asgui, an accounting system graphical user
michael@1: //  interface which can be found at http://www.ossp.org/pkg/tool/asgui/.
michael@1: //
michael@1: //  Permission to use, copy, modify, and distribute this software for
michael@1: //  any purpose with or without fee is hereby granted, provided that
michael@1: //  the above copyright notice and this permission notice appear in all
michael@1: //  copies.
michael@1: //
michael@1: //  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
michael@1: //  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
michael@1: //  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
michael@1: //  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
michael@1: //  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@1: //  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@1: //  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
michael@1: //  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
michael@1: //  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
michael@1: //  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
michael@1: //  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
michael@1: //  SUCH DAMAGE.
michael@1: //
michael@1: //  as_rand.cpp: ISO C++ implementation
michael@1: //
michael@1: 
michael@1: #include <fcntl.h>
michael@1: #include <cerrno>
michael@1: 
michael@1: #include "as_rand.h"
michael@1: 
michael@1: #if HAVE_UNISTD_H
michael@1: #include <unistd.h>
michael@1: #endif // HAVE_UNISTD_H
michael@1: #if HAVE_STDLIB_H
michael@1: #include <stdlib.h>
michael@1: #endif // HAVE_STDLIB_H
michael@1: 
michael@1: #if TIME_WITH_SYS_TIME
michael@1: #include <sys/time.h>
michael@1: #include <time.h>
michael@1: #else
michael@1: #if HAVE_SYS_TIME_H
michael@1: #include <sys/time.h>
michael@1: #else
michael@1: #include <time.h>
michael@1: #endif // HAVE_SYS_TIME_H
michael@1: #endif // TIME_WITH_SYS_TIME
michael@1: 
michael@1: 
michael@1: namespace AS {
michael@1: 
michael@1: // Constructor
michael@1: Rand::Rand(void)
michael@1: {
michael@1:     this->nFd = -4; // Object fresh status
michael@1:     this->openDevice();   // Open the random device
michael@1: //    if (this->nFd < 0)
michael@1: //        throw Genexcept("Could not open /dev/urandom or /dev/random.");
michael@1: }
michael@1: 
michael@1: // Destructor
michael@1: Rand::~Rand(void)
michael@1: {
michael@1:     this->closeDevice();  // Close the random device
michael@1:     this->nFd = -4; // Return this object to its fresh status
michael@1: }
michael@1: 
michael@1: //
michael@1: // Rand::openDevice(void)
michael@1: // Open the random device associated with this object
michael@1: //
michael@1: void Rand::openDevice(void)
michael@1: {
michael@1:     struct timeval Time;
michael@1: 
michael@1:     if (this->nFd == -4) {  // -4 indicates a fresh object
michael@1:         gettimeofday(&Time, 0);
michael@1:         this->nFd = open("/dev/urandom", O_RDONLY);
michael@1:         if (this->nFd == -1)
michael@1:             this->nFd = open("/dev/random", O_RDONLY | O_NONBLOCK);
michael@1:         srand((getpid() << 16) ^ getuid() ^ Time.tv_sec ^ Time.tv_usec); // Seed
michael@1:     }
michael@1: 
michael@1:     // Improve randomness by stirring in entropy
michael@1:     gettimeofday(&Time, 0);
michael@1:     for (int nIter = (Time.tv_sec ^ Time.tv_usec) & 0x1F; nIter > 0; nIter--)
michael@1:         rand();
michael@1: }
michael@1: 
michael@1: //
michael@1: // Rand::closeDevice(void)
michael@1: // Close the random device associated with this object
michael@1: //
michael@1: void Rand::closeDevice(void)
michael@1: {
michael@1:     if (this->nFd >= 0)
michael@1:         close(this->nFd);
michael@1: }
michael@1: 
michael@1: //
michael@1: // Rand::genData(void *pvBuf, int nBytes)
michael@1: // Generate a series of random data from the system
michael@1: // standard random devices /dev/[u|s]random
michael@1: //
michael@1: void Rand::genData(void *pBuf, int nBytes)
michael@1: {
michael@1:     int nRead = 0;
michael@1:     int nLost = 0;
michael@1:     char *szOut = (char *)pBuf;
michael@1: 
michael@1:     if (this->nFd >= 0) {
michael@1:         while (nBytes > 0) {
michael@1:             nRead = read(this->nFd, szOut, nBytes);
michael@1:             if ((nRead < 0) && ((errno == EINTR) || (errno == EAGAIN)))
michael@1:                 continue;
michael@1:             if (nRead <= 0) {
michael@1:                 if (nLost++ == 8)
michael@1:                     break;
michael@1:                 continue;
michael@1:             }
michael@1:             nBytes -= nRead;
michael@1:             szOut += nRead;
michael@1:             nLost = 0;
michael@1:         }
michael@1:     }
michael@1: 
michael@1:     // For systems with no /dev/random, we do the next best thing
michael@1:     for (int nIter = 0;  nIter< nBytes; nIter++)
michael@1:         *szOut++ = rand() & 0xFF;
michael@1: }
michael@1: } // namespace AS