79 lines
2.6 KiB
Go
79 lines
2.6 KiB
Go
// 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 freebsd 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(family, sotype, proto int) (int, error) {
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s, err := syscall.Socket(family, sotype|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, proto)
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// On Linux the SOCK_NONBLOCK and SOCK_CLOEXEC flags were
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// introduced in 2.6.27 kernel and on FreeBSD both flags were
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// introduced in 10 kernel. If we get an EINVAL error on Linux
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// or EPROTONOSUPPORT error on FreeBSD, fall back to using
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// socket without them.
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if err == nil || (err != syscall.EPROTONOSUPPORT && 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(family, sotype, proto)
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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(s int) (int, syscall.Sockaddr, error) {
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ns, sa, err := syscall.Accept4(s, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
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// On Linux the accept4 system call was introduced in 2.6.28
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// kernel and on FreeBSD it was introduced in 10 kernel. If we
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// get an ENOSYS error on both Linux and FreeBSD, or EINVAL
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// error on Linux, fall back to using accept.
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switch err {
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default: // nil and errors other than the ones listed
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return ns, sa, err
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case syscall.ENOSYS: // syscall missing
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case syscall.EINVAL: // some Linux use this instead of ENOSYS
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case syscall.EACCES: // some Linux use this instead of ENOSYS
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case syscall.EFAULT: // some Linux use this instead of ENOSYS
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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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ns, sa, err = syscall.Accept(s)
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if err == nil {
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syscall.CloseOnExec(ns)
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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(ns, true); err != nil {
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syscall.Close(ns)
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return -1, nil, err
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}
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return ns, sa, nil
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}
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