github.com/q45/go@v0.0.0-20151101211701-a4fb8c13db3f/src/net/sys_cloexec.go (about)

     1  // Copyright 2013 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 sysSocket and accept for platforms that do not
     6  // provide a fast path for setting SetNonblock and CloseOnExec.
     7  
     8  // +build darwin dragonfly nacl netbsd openbsd solaris
     9  
    10  package net
    11  
    12  import (
    13  	"os"
    14  	"syscall"
    15  )
    16  
    17  // Wrapper around the socket system call that marks the returned file
    18  // descriptor as nonblocking and close-on-exec.
    19  func sysSocket(family, sotype, proto int) (int, error) {
    20  	// See ../syscall/exec_unix.go for description of ForkLock.
    21  	syscall.ForkLock.RLock()
    22  	s, err := socketFunc(family, sotype, proto)
    23  	if err == nil {
    24  		syscall.CloseOnExec(s)
    25  	}
    26  	syscall.ForkLock.RUnlock()
    27  	if err != nil {
    28  		return -1, os.NewSyscallError("socket", err)
    29  	}
    30  	if err = syscall.SetNonblock(s, true); err != nil {
    31  		closeFunc(s)
    32  		return -1, os.NewSyscallError("setnonblock", err)
    33  	}
    34  	return s, nil
    35  }
    36  
    37  // Wrapper around the accept system call that marks the returned file
    38  // descriptor as nonblocking and close-on-exec.
    39  func accept(s int) (int, syscall.Sockaddr, error) {
    40  	// See ../syscall/exec_unix.go for description of ForkLock.
    41  	// It is probably okay to hold the lock across syscall.Accept
    42  	// because we have put fd.sysfd into non-blocking mode.
    43  	// However, a call to the File method will put it back into
    44  	// blocking mode. We can't take that risk, so no use of ForkLock here.
    45  	ns, sa, err := acceptFunc(s)
    46  	if err == nil {
    47  		syscall.CloseOnExec(ns)
    48  	}
    49  	if err != nil {
    50  		return -1, nil, os.NewSyscallError("accept", err)
    51  	}
    52  	if err = syscall.SetNonblock(ns, true); err != nil {
    53  		closeFunc(ns)
    54  		return -1, nil, os.NewSyscallError("setnonblock", err)
    55  	}
    56  	return ns, sa, nil
    57  }