sock_cloexec_solaris.go

     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  
    11  package poll
    12  
    13  import (
    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.
    20  func 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
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