1// Copyright 2024 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// This file implements accept for platforms that provide a fast path for 6// setting SetNonblock and CloseOnExec, but don't necessarily have accept4. 7// The accept4(3c) function was added to Oracle Solaris in the Solaris 11.4.0 8// release. Thus, on releases prior to 11.4, we fall back to the combination 9// of accept(3c) and fcntl(2). 10 11package poll 12 13import ( 14 "internal/syscall/unix" 15 "syscall" 16) 17 18// Wrapper around the accept system call that marks the returned file 19// descriptor as nonblocking and close-on-exec. 20func accept(s int) (int, syscall.Sockaddr, string, error) { 21 // Perform a cheap test and try the fast path first. 22 if unix.SupportAccept4() { 23 ns, sa, err := Accept4Func(s, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC) 24 if err != nil { 25 return -1, nil, "accept4", err 26 } 27 return ns, sa, "", nil 28 } 29 30 // See ../syscall/exec_unix.go for description of ForkLock. 31 // It is probably okay to hold the lock across syscall.Accept 32 // because we have put fd.sysfd into non-blocking mode. 33 // However, a call to the File method will put it back into 34 // blocking mode. We can't take that risk, so no use of ForkLock here. 35 ns, sa, err := AcceptFunc(s) 36 if err == nil { 37 syscall.CloseOnExec(ns) 38 } 39 if err != nil { 40 return -1, nil, "accept", err 41 } 42 if err = syscall.SetNonblock(ns, true); err != nil { 43 CloseFunc(ns) 44 return -1, nil, "setnonblock", err 45 } 46 return ns, sa, "", nil 47} 48