165 lines
3.9 KiB
C++
165 lines
3.9 KiB
C++
/*
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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 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
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#include "io.hpp"
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#include "cast.hpp"
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#include "except.hpp"
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#include "posix/fd.hpp"
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#include "posix/except.hpp"
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#include <sys/stat.h>
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using cruft::detail::posix::mapped_file;
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///////////////////////////////////////////////////////////////////////////////
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namespace {
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struct overflow_error : public cruft::error {
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std::ostream& describe (std::ostream &os) const override
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{
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return os << "mapping is too large for the system";
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}
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};
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}
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//////////////////////////////////////////////////////////////////////////////
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mapped_file::mapped_file (const std::filesystem::path &path,
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int fflags,
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int mflags):
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mapped_file (cruft::posix::fd (path, fflags), mflags)
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{ ; }
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//-----------------------------------------------------------------------------
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mapped_file::mapped_file (::cruft::posix::fd const &src, int const mflags)
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{
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struct stat meta;
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::cruft::posix::error::try_value (fstat (src, &meta));
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// Zero length mappings aren't allowed by POSIX (even though they're
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// accepted by some systems; like Linux)
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if (meta.st_size == 0) {
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m_data = nullptr;
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m_size = 0;
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return;
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}
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// Ensure we're not trying to map more than our address space allows.
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//
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// It's a little nasty, but we protect a
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if constexpr (sizeof (meta.st_size) > sizeof (size_t)) {
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auto const hi = cruft::cast::lossless<off_t> (std::numeric_limits<size_t>::max ());
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if (meta.st_size > hi)
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throw overflow_error ();
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}
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m_size = cruft::cast::lossless<size_t> (meta.st_size);
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m_data = static_cast<u08*> (mmap (nullptr, m_size, mflags, MAP_SHARED, src, 0));
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if (m_data == MAP_FAILED)
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::cruft::posix::error::throw_code ();
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}
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//-----------------------------------------------------------------------------
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mapped_file::mapped_file (cruft::mapped_file &&rhs) noexcept
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: m_data (std::exchange (rhs.m_data, nullptr))
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, m_size (std::exchange (rhs.m_size, 0))
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{ ; }
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//----------------------------------------------------------------------------
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mapped_file::~mapped_file ()
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{
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if (!m_data)
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return;
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munmap (m_data, m_size);
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}
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//////////////////////////////////////////////////////////////////////////////
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size_t
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mapped_file::size (void) const
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{
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return m_size;
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}
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//-----------------------------------------------------------------------------
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bool
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mapped_file::empty (void) const
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{
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return size () == 0;
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}
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//////////////////////////////////////////////////////////////////////////////
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uint8_t*
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mapped_file::data (void) &
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{
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return m_data;
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}
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//----------------------------------------------------------------------------
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const uint8_t*
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mapped_file::data (void) const &
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{
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return m_data;
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}
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//----------------------------------------------------------------------------
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uint8_t*
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mapped_file::begin (void) &
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{
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return data ();
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}
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//----------------------------------------------------------------------------
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uint8_t*
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mapped_file::end (void) &
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{
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return data () + size ();
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}
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//-----------------------------------------------------------------------------
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const uint8_t*
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mapped_file::begin (void) const &
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{
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return data ();
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}
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//-----------------------------------------------------------------------------
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const uint8_t*
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mapped_file::end (void) const &
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{
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return data () + size ();
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}
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//----------------------------------------------------------------------------
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const uint8_t*
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mapped_file::cbegin (void) const &
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{
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return data ();
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}
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//----------------------------------------------------------------------------
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const uint8_t*
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mapped_file::cend (void) const &
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{
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return data () + size ();
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}
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