KasmVNC/common/rdr/RandomStream.cxx
Pierre Ossman 92c7695981 Create common base classes for buffered streams
Most streams are backed by a memory buffer. Create common base classes
for this functionality to avoid code duplication.
2021-03-29 10:11:16 +03:00

105 lines
2.7 KiB
C++

/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#include <rdr/RandomStream.h>
#include <rdr/Exception.h>
#include <time.h>
#include <stdlib.h>
#ifndef WIN32
#include <unistd.h>
#include <errno.h>
#else
#define getpid() GetCurrentProcessId()
#ifndef RFB_HAVE_WINCRYPT
#pragma message(" NOTE: Not building WinCrypt-based RandomStream")
#endif
#endif
using namespace rdr;
unsigned int RandomStream::seed;
RandomStream::RandomStream()
{
#ifdef RFB_HAVE_WINCRYPT
provider = 0;
if (!CryptAcquireContext(&provider, 0, 0, PROV_RSA_FULL, 0)) {
if (GetLastError() == (DWORD)NTE_BAD_KEYSET) {
if (!CryptAcquireContext(&provider, 0, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET)) {
fprintf(stderr, "RandomStream: unable to create keyset\n");
provider = 0;
}
} else {
fprintf(stderr, "RandomStream: unable to acquire context\n");
provider = 0;
}
}
if (!provider) {
#else
#ifndef WIN32
fp = fopen("/dev/urandom", "r");
if (!fp)
fp = fopen("/dev/random", "r");
if (!fp) {
#else
{
#endif
#endif
fprintf(stderr,"RandomStream: warning: no OS supplied random source - using rand()\n");
seed += (unsigned int) time(0) + getpid() + getpid() * 987654 + rand();
srand(seed);
}
}
RandomStream::~RandomStream() {
#ifdef RFB_HAVE_WINCRYPT
if (provider)
CryptReleaseContext(provider, 0);
#endif
#ifndef WIN32
if (fp) fclose(fp);
#endif
}
bool RandomStream::fillBuffer(size_t maxSize, bool wait) {
#ifdef RFB_HAVE_WINCRYPT
if (provider) {
if (!CryptGenRandom(provider, maxSize, (U8*)end))
throw rdr::SystemException("unable to CryptGenRandom", GetLastError());
end += maxSize;
} else {
#else
#ifndef WIN32
if (fp) {
size_t n = fread((U8*)end, 1, maxSize, fp);
if (n <= 0)
throw rdr::SystemException("reading /dev/urandom or /dev/random failed",
errno);
end += n;
} else {
#else
{
#endif
#endif
for (size_t i=0; i<maxSize; i++)
*(U8*)end++ = (int) (256.0*rand()/(RAND_MAX+1.0));
}
return true;
}