mirror of
https://github.com/autc04/Retro68.git
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70 lines
2.1 KiB
Go
70 lines
2.1 KiB
Go
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// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This file implements sysSocket and accept for platforms that
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// provide a fast path for setting SetNonblock and CloseOnExec.
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// +build linux
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package net
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import "syscall"
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// Wrapper around the socket system call that marks the returned file
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// descriptor as nonblocking and close-on-exec.
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func sysSocket(f, t, p int) (int, error) {
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s, err := syscall.Socket(f, t|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, p)
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// The SOCK_NONBLOCK and SOCK_CLOEXEC flags were introduced in
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// Linux 2.6.27. If we get an EINVAL error, fall back to
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// using socket without them.
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if err == nil || err != syscall.EINVAL {
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return s, err
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}
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// See ../syscall/exec_unix.go for description of ForkLock.
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syscall.ForkLock.RLock()
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s, err = syscall.Socket(f, t, p)
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if err == nil {
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syscall.CloseOnExec(s)
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}
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syscall.ForkLock.RUnlock()
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if err != nil {
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return -1, err
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}
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if err = syscall.SetNonblock(s, true); err != nil {
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syscall.Close(s)
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return -1, err
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}
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return s, nil
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}
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// Wrapper around the accept system call that marks the returned file
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// descriptor as nonblocking and close-on-exec.
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func accept(fd int) (int, syscall.Sockaddr, error) {
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nfd, sa, err := syscall.Accept4(fd, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
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// The accept4 system call was introduced in Linux 2.6.28. If
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// we get an ENOSYS or EINVAL error, fall back to using accept.
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if err == nil || (err != syscall.ENOSYS && err != syscall.EINVAL) {
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return nfd, sa, err
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}
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// See ../syscall/exec_unix.go for description of ForkLock.
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// It is probably okay to hold the lock across syscall.Accept
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// because we have put fd.sysfd into non-blocking mode.
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// However, a call to the File method will put it back into
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// blocking mode. We can't take that risk, so no use of ForkLock here.
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nfd, sa, err = syscall.Accept(fd)
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if err == nil {
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syscall.CloseOnExec(nfd)
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}
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if err != nil {
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return -1, nil, err
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}
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if err = syscall.SetNonblock(nfd, true); err != nil {
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syscall.Close(nfd)
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return -1, nil, err
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}
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return nfd, sa, nil
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}
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