libgo/go/net/sys_cloexec.go

   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 freebsd netbsd openbsd
   9
  10 package net
  11
  12 import "syscall"
  13
  14 // Wrapper around the socket system call that marks the returned file
  15 // descriptor as nonblocking and close-on-exec.
  16 func sysSocket(f, t, p int) (int, error) {
  17         // See ../syscall/exec_unix.go for description of ForkLock.
  18         syscall.ForkLock.RLock()
  19         s, err := syscall.Socket(f, t, p)
  20         if err == nil {
  21                 syscall.CloseOnExec(s)
  22         }
  23         syscall.ForkLock.RUnlock()
  24         if err != nil {
  25                 return -1, err
  26         }
  27         if err = syscall.SetNonblock(s, true); err != nil {
  28                 syscall.Close(s)
  29                 return -1, err
  30         }
  31         return s, nil
  32 }
  33
  34 // Wrapper around the accept system call that marks the returned file
  35 // descriptor as nonblocking and close-on-exec.
  36 func accept(fd int) (int, syscall.Sockaddr, error) {
  37         // See ../syscall/exec_unix.go for description of ForkLock.
  38         // It is probably okay to hold the lock across syscall.Accept
  39         // because we have put fd.sysfd into non-blocking mode.
  40         // However, a call to the File method will put it back into
  41         // blocking mode. We can't take that risk, so no use of ForkLock here.
  42         nfd, sa, err := syscall.Accept(fd)
  43         if err == nil {
  44                 syscall.CloseOnExec(nfd)
  45         }
  46         if err != nil {
  47                 return -1, nil, err
  48         }
  49         if err = syscall.SetNonblock(nfd, true); err != nil {
  50                 syscall.Close(nfd)
  51                 return -1, nil, err
  52         }
  53         return nfd, sa, nil
  54 }