mirror of
https://github.com/matrix-construct/construct
synced 2024-11-18 07:50:57 +01:00
130 lines
3.5 KiB
C++
130 lines
3.5 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_UTIL_SYSCALL_H
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// Declaring this here eliminates the need to include <unistd.h> for it
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extern "C" long syscall(long, ...) noexcept;
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namespace ircd::util
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{
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template<class function, class... args> long syscall(function&& f, args&&... a);
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template<long number, class... args> long syscall(args&&... a);
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template<class function, class... args> long syscall_nointr(function&& f, args&&... a);
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template<long number, class... args> long syscall_nointr(args&&... a);
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}
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/// Posix system call template to check for returned error value and throw the
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/// approps errno in the proper std::system_error exception. Note the usage
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/// here, the libc wrapper function is the first argument i.e:
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/// syscall(::foo, bar, baz) not syscall(::foo(bar, baz));
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///
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template<class function,
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class... args>
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long
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ircd::util::syscall(function&& f,
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args&&... a)
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{
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const auto ret
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{
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f(std::forward<args>(a)...)
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};
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if(unlikely(ret == -1))
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throw std::system_error
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{
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errno, std::system_category()
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};
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return ret;
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}
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/// Posix system call template to check for returned error value and throw the
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/// approps errno in the proper std::system_error exception. This template
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/// requires a system call number in the parameters. The arguments are only
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/// the actual arguments passed to the syscall because the number is given
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/// in the template.
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///
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template<long number,
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class... args>
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long
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ircd::util::syscall(args&&... a)
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{
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const auto ret
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{
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::syscall(number, std::forward<args>(a)...)
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};
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if(unlikely(ret == -1))
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throw std::system_error
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{
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errno, std::system_category()
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};
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return ret;
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}
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/// Uninterruptible posix system call template to check for returned error
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/// value and throw the approps errno in the proper std::system_error
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/// exception. Note the usage here, the libc wrapper function is the first
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/// argument i.e: syscall(::foo, bar, baz) not syscall(::foo(bar, baz));
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///
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/// The syscall is restarted until it no longer returns with EINTR.
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///
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template<class function,
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class... args>
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long
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ircd::util::syscall_nointr(function&& f,
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args&&... a)
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{
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long ret; do
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{
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ret = f(std::forward<args>(a)...);
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}
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while(unlikely(ret == -1 && errno == EINTR));
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if(unlikely(ret == -1))
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throw std::system_error
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{
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errno, std::system_category()
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};
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return ret;
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}
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/// Uninterruptible posix system call template to check for returned error
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/// value and throw the approps errno in the proper std::system_error
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/// exception. This template requires a system call number in the parameters.
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/// The arguments are only the actual arguments passed to the syscall because
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/// the number is given in the template.
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///
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/// The syscall is restarted until it no longer returns with EINTR.
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///
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template<long number,
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class... args>
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long
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ircd::util::syscall_nointr(args&&... a)
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{
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long ret; do
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{
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ret = ::syscall(number, std::forward<args>(a)...);
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}
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while(unlikely(ret == -1 && errno == EINTR));
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if(unlikely(ret == -1))
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throw std::system_error
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{
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errno, std::system_category()
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};
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return ret;
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}
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