63 lines
1.4 KiB
C++
63 lines
1.4 KiB
C++
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/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2019 Danny Robson <danny@nerdcruft.net>
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*/
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#include "system_linux.hpp"
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#include "../posix/except.hpp"
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#include "../io.hpp"
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#include <sys/ioctl.h>
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#include <linux/random.h>
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using cruft::rand::linux::device;
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///////////////////////////////////////////////////////////////////////////////
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static std::string const& default_source (void)
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{
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static std::string const s_path = "/dev/urandom";
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return s_path;
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}
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//-----------------------------------------------------------------------------
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device::device ():
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device (default_source ())
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{ ; }
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//-----------------------------------------------------------------------------
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device::device (std::string const &token)
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: m_fd (token, O_RDONLY | O_BINARY)
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{ ; }
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///////////////////////////////////////////////////////////////////////////////
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device::result_type
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device::operator() (void)
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{
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result_type res;
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cruft::read (m_fd, cruft::make_byte_view<u08> (res));
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return res;
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}
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///////////////////////////////////////////////////////////////////////////////
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double
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device::entropy () const noexcept
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{
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int val;
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cruft::posix::error::try_code (
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ioctl (m_fd.native (), RNDGETENTCNT, &val)
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);
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return val < 0 ? 0. : double (val);
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}
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