/* boost uuid/detail/random_provider_posix implementation
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*
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* Copyright Jens Maurer 2000
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* Copyright 2007 Andy Tompkins.
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* Copyright Steven Watanabe 2010-2011
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* Copyright 2017 James E. King III
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*
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* Distributed under the Boost Software License, Version 1.0. (See
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* accompanying file LICENSE_1_0.txt or copy at
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* https://www.boost.org/LICENSE_1_0.txt)
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*
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* $Id$
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*/
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#include <boost/config.hpp>
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#include <boost/core/ignore_unused.hpp>
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#include <boost/move/core.hpp>
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#include <boost/throw_exception.hpp>
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#include <boost/uuid/entropy_error.hpp>
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#include <cerrno>
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#include <cstddef>
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#include <fcntl.h> // open
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#include <sys/stat.h>
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#include <sys/types.h>
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#if defined(BOOST_HAS_UNISTD_H)
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#include <unistd.h>
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#endif
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#ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE
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#define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE ::close
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#endif
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#ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN
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#define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN ::open
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#endif
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#ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ
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#define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ ::read
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#endif
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namespace boost {
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namespace uuids {
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namespace detail {
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class random_provider_base
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{
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BOOST_MOVABLE_BUT_NOT_COPYABLE(random_provider_base)
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public:
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random_provider_base()
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: fd_(-1)
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{
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int flags = O_RDONLY;
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#if defined(O_CLOEXEC)
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flags |= O_CLOEXEC;
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#endif
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fd_ = BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN("/dev/urandom", flags);
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if (BOOST_UNLIKELY(-1 == fd_))
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{
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int err = errno;
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BOOST_THROW_EXCEPTION(entropy_error(err, "open /dev/urandom"));
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}
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}
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random_provider_base(BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT : fd_(that.fd_)
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{
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that.fd_ = -1;
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}
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random_provider_base& operator= (BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT
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{
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destroy();
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fd_ = that.fd_;
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that.fd_ = -1;
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return *this;
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}
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~random_provider_base() BOOST_NOEXCEPT
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{
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destroy();
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}
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//! Obtain entropy and place it into a memory location
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//! \param[in] buf the location to write entropy
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//! \param[in] siz the number of bytes to acquire
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void get_random_bytes(void *buf, std::size_t siz)
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{
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std::size_t offset = 0;
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while (offset < siz)
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{
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ssize_t sz = BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ(
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fd_, static_cast<char *>(buf) + offset, siz - offset);
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if (BOOST_UNLIKELY(sz < 0))
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{
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int err = errno;
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if (err == EINTR)
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continue;
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BOOST_THROW_EXCEPTION(entropy_error(err, "read"));
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}
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offset += sz;
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}
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}
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private:
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void destroy() BOOST_NOEXCEPT
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{
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if (fd_ >= 0)
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{
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boost::ignore_unused(BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE(fd_));
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}
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}
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private:
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int fd_;
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};
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} // detail
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} // uuids
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} // boost
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