file_windows.go

     1  // Copyright 2011 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  package net
     6  
     7  import (
     8  	"internal/syscall/windows"
     9  	"os"
    10  	"syscall"
    11  )
    12  
    13  const _SO_TYPE = windows.SO_TYPE
    14  
    15  func dupSocket(h syscall.Handle) (syscall.Handle, error) {
    16  	var info syscall.WSAProtocolInfo
    17  	err := windows.WSADuplicateSocket(h, uint32(syscall.Getpid()), &info)
    18  	if err != nil {
    19  		return 0, err
    20  	}
    21  	return windows.WSASocket(-1, -1, -1, &info, 0, windows.WSA_FLAG_OVERLAPPED|windows.WSA_FLAG_NO_HANDLE_INHERIT)
    22  }
    23  
    24  func dupFileSocket(f *os.File) (syscall.Handle, error) {
    25  	// Call Fd to disassociate the IOCP from the handle,
    26  	// it is not safe to share a duplicated handle
    27  	// that is associated with IOCP.
    28  	// Don't use the returned fd, as it might be closed
    29  	// if f happens to be the last reference to the file.
    30  	f.Fd()
    31  
    32  	sc, err := f.SyscallConn()
    33  	if err != nil {
    34  		return 0, err
    35  	}
    36  
    37  	var h syscall.Handle
    38  	var syserr error
    39  	err = sc.Control(func(fd uintptr) {
    40  		h, syserr = dupSocket(syscall.Handle(fd))
    41  	})
    42  	if err != nil {
    43  		err = syserr
    44  	}
    45  	if err != nil {
    46  		return 0, err
    47  	}
    48  	return h, nil
    49  }
    50
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