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Source file src/os/exec_windows.go

Documentation: os

  // Copyright 2009 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package os
  
  import (
  	"errors"
  	"runtime"
  	"sync/atomic"
  	"syscall"
  	"time"
  	"unsafe"
  )
  
  func (p *Process) wait() (ps *ProcessState, err error) {
  	handle := atomic.LoadUintptr(&p.handle)
  	s, e := syscall.WaitForSingleObject(syscall.Handle(handle), syscall.INFINITE)
  	switch s {
  	case syscall.WAIT_OBJECT_0:
  		break
  	case syscall.WAIT_FAILED:
  		return nil, NewSyscallError("WaitForSingleObject", e)
  	default:
  		return nil, errors.New("os: unexpected result from WaitForSingleObject")
  	}
  	var ec uint32
  	e = syscall.GetExitCodeProcess(syscall.Handle(handle), &ec)
  	if e != nil {
  		return nil, NewSyscallError("GetExitCodeProcess", e)
  	}
  	var u syscall.Rusage
  	e = syscall.GetProcessTimes(syscall.Handle(handle), &u.CreationTime, &u.ExitTime, &u.KernelTime, &u.UserTime)
  	if e != nil {
  		return nil, NewSyscallError("GetProcessTimes", e)
  	}
  	p.setDone()
  	// NOTE(brainman): It seems that sometimes process is not dead
  	// when WaitForSingleObject returns. But we do not know any
  	// other way to wait for it. Sleeping for a while seems to do
  	// the trick sometimes. So we will sleep and smell the roses.
  	defer time.Sleep(5 * time.Millisecond)
  	defer p.Release()
  	return &ProcessState{p.Pid, syscall.WaitStatus{ExitCode: ec}, &u}, nil
  }
  
  func terminateProcess(pid, exitcode int) error {
  	h, e := syscall.OpenProcess(syscall.PROCESS_TERMINATE, false, uint32(pid))
  	if e != nil {
  		return NewSyscallError("OpenProcess", e)
  	}
  	defer syscall.CloseHandle(h)
  	e = syscall.TerminateProcess(h, uint32(exitcode))
  	return NewSyscallError("TerminateProcess", e)
  }
  
  func (p *Process) signal(sig Signal) error {
  	handle := atomic.LoadUintptr(&p.handle)
  	if handle == uintptr(syscall.InvalidHandle) {
  		return syscall.EINVAL
  	}
  	if p.done() {
  		return errors.New("os: process already finished")
  	}
  	if sig == Kill {
  		err := terminateProcess(p.Pid, 1)
  		runtime.KeepAlive(p)
  		return err
  	}
  	// TODO(rsc): Handle Interrupt too?
  	return syscall.Errno(syscall.EWINDOWS)
  }
  
  func (p *Process) release() error {
  	handle := atomic.LoadUintptr(&p.handle)
  	if handle == uintptr(syscall.InvalidHandle) {
  		return syscall.EINVAL
  	}
  	e := syscall.CloseHandle(syscall.Handle(handle))
  	if e != nil {
  		return NewSyscallError("CloseHandle", e)
  	}
  	atomic.StoreUintptr(&p.handle, uintptr(syscall.InvalidHandle))
  	// no need for a finalizer anymore
  	runtime.SetFinalizer(p, nil)
  	return nil
  }
  
  func findProcess(pid int) (p *Process, err error) {
  	const da = syscall.STANDARD_RIGHTS_READ |
  		syscall.PROCESS_QUERY_INFORMATION | syscall.SYNCHRONIZE
  	h, e := syscall.OpenProcess(da, false, uint32(pid))
  	if e != nil {
  		return nil, NewSyscallError("OpenProcess", e)
  	}
  	return newProcess(pid, uintptr(h)), nil
  }
  
  func init() {
  	p := syscall.GetCommandLine()
  	cmd := syscall.UTF16ToString((*[0xffff]uint16)(unsafe.Pointer(p))[:])
  	if len(cmd) == 0 {
  		arg0, _ := Executable()
  		Args = []string{arg0}
  	} else {
  		Args = commandLineToArgv(cmd)
  	}
  }
  
  // appendBSBytes appends n '\\' bytes to b and returns the resulting slice.
  func appendBSBytes(b []byte, n int) []byte {
  	for ; n > 0; n-- {
  		b = append(b, '\\')
  	}
  	return b
  }
  
  // readNextArg splits command line string cmd into next
  // argument and command line remainder.
  func readNextArg(cmd string) (arg []byte, rest string) {
  	var b []byte
  	var inquote bool
  	var nslash int
  	for ; len(cmd) > 0; cmd = cmd[1:] {
  		c := cmd[0]
  		switch c {
  		case ' ', '\t':
  			if !inquote {
  				return appendBSBytes(b, nslash), cmd[1:]
  			}
  		case '"':
  			b = appendBSBytes(b, nslash/2)
  			if nslash%2 == 0 {
  				// use "Prior to 2008" rule from
  				// http://daviddeley.com/autohotkey/parameters/parameters.htm
  				// section 5.2 to deal with double double quotes
  				if inquote && len(cmd) > 1 && cmd[1] == '"' {
  					b = append(b, c)
  					cmd = cmd[1:]
  				}
  				inquote = !inquote
  			} else {
  				b = append(b, c)
  			}
  			nslash = 0
  			continue
  		case '\\':
  			nslash++
  			continue
  		}
  		b = appendBSBytes(b, nslash)
  		nslash = 0
  		b = append(b, c)
  	}
  	return appendBSBytes(b, nslash), ""
  }
  
  // commandLineToArgv splits a command line into individual argument
  // strings, following the Windows conventions documented
  // at http://daviddeley.com/autohotkey/parameters/parameters.htm#WINARGV
  func commandLineToArgv(cmd string) []string {
  	var args []string
  	for len(cmd) > 0 {
  		if cmd[0] == ' ' || cmd[0] == '\t' {
  			cmd = cmd[1:]
  			continue
  		}
  		var arg []byte
  		arg, cmd = readNextArg(cmd)
  		args = append(args, string(arg))
  	}
  	return args
  }
  
  func ftToDuration(ft *syscall.Filetime) time.Duration {
  	n := int64(ft.HighDateTime)<<32 + int64(ft.LowDateTime) // in 100-nanosecond intervals
  	return time.Duration(n*100) * time.Nanosecond
  }
  
  func (p *ProcessState) userTime() time.Duration {
  	return ftToDuration(&p.rusage.UserTime)
  }
  
  func (p *ProcessState) systemTime() time.Duration {
  	return ftToDuration(&p.rusage.KernelTime)
  }
  

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