libgo/go/os/wait_wait6.go

   1 // Copyright 2016 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 // +build freebsd
   6
   7 package os
   8
   9 import (
  10         "runtime"
  11         "syscall"
  12 )
  13
  14 const _P_PID = 0
  15
  16 // blockUntilWaitable attempts to block until a call to p.Wait will
  17 // succeed immediately, and returns whether it has done so.
  18 // It does not actually call p.Wait.
  19 func (p *Process) blockUntilWaitable() (bool, error) {
  20         var errno syscall.Errno
  21         // The arguments on 32-bit FreeBSD look like the following:
  22         // - freebsd32_wait6_args{ idtype, id1, id2, status, options, wrusage, info } or
  23         // - freebsd32_wait6_args{ idtype, pad, id1, id2, status, options, wrusage, info } when PAD64_REQUIRED=1 on ARM, MIPS or PowerPC
  24         if runtime.GOARCH == "386" {
  25                 _, _, errno = syscall.Syscall9(syscall.SYS_WAIT6, _P_PID, uintptr(p.Pid), 0, 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0, 0, 0)
  26         } else if runtime.GOARCH == "arm" {
  27                 _, _, errno = syscall.Syscall9(syscall.SYS_WAIT6, _P_PID, 0, uintptr(p.Pid), 0, 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0, 0)
  28         } else {
  29                 _, _, errno = syscall.Syscall6(syscall.SYS_WAIT6, _P_PID, uintptr(p.Pid), 0, syscall.WEXITED|syscall.WNOWAIT, 0, 0)
  30         }
  31         if errno != 0 {
  32                 // The wait6 system call is supported only on FreeBSD
  33                 // 9.3 and above, so it may return an ENOSYS error.
  34                 if errno == syscall.ENOSYS {
  35                         return false, nil
  36                 }
  37                 return false, NewSyscallError("wait6", errno)
  38         }
  39         return true, nil
  40 }