go.sys/windows: delete StartProcess and Exec

These are being deleted from go.sys because in general they can
only be implemented in close coordination with the runtime.

LGTM=alex.brainman
R=alex.brainman
CC=golang-codereviews
https://golang.org/cl/132010043

windows/exec_windows.go

@@ -6,14 +6,7 @@
 
 package windows
 
-import (
-	"sync"
-	"syscall"
-	"unicode/utf16"
-	"unsafe"
-)
-
-var ForkLock sync.RWMutex
+import "syscall"
 
 // EscapeArg rewrites command line argument s as prescribed
 // in http://msdn.microsoft.com/en-us/library/ms880421.
@@ -82,54 +75,10 @@ func EscapeArg(s string) string {
 	return string(qs[:j])
 }
 
-// makeCmdLine builds a command line out of args by escaping "special"
-// characters and joining the arguments with spaces.
-func makeCmdLine(args []string) string {
-	var s string
-	for _, v := range args {
-		if s != "" {
-			s += " "
-		}
-		s += EscapeArg(v)
-	}
-	return s
-}
-
-// createEnvBlock converts an array of environment strings into
-// the representation required by CreateProcess: a sequence of NUL
-// terminated strings followed by a nil.
-// Last bytes are two UCS-2 NULs, or four NUL bytes.
-func createEnvBlock(envv []string) *uint16 {
-	if len(envv) == 0 {
-		return &utf16.Encode([]rune("\x00\x00"))[0]
-	}
-	length := 0
-	for _, s := range envv {
-		length += len(s) + 1
-	}
-	length += 1
-
-	b := make([]byte, length)
-	i := 0
-	for _, s := range envv {
-		l := len(s)
-		copy(b[i:i+l], []byte(s))
-		copy(b[i+l:i+l+1], []byte{0})
-		i = i + l + 1
-	}
-	copy(b[i:i+1], []byte{0})
-
-	return &utf16.Encode([]rune(string(b)))[0]
-}
-
 func CloseOnExec(fd Handle) {
 	SetHandleInformation(Handle(fd), HANDLE_FLAG_INHERIT, 0)
 }
 
-func SetNonblock(fd Handle, nonblocking bool) (err error) {
-	return nil
-}
-
 // FullPath retrieves the full path of the specified file.
 func FullPath(name string) (path string, err error) {
 	p, err := UTF16PtrFromString(name)
@@ -154,188 +103,3 @@ func FullPath(name string) (path string, err error) {
 	}
 	return UTF16ToString(buf[:n]), nil
 }
-
-func isSlash(c uint8) bool {
-	return c == '\\' || c == '/'
-}
-
-func normalizeDir(dir string) (name string, err error) {
-	ndir, err := FullPath(dir)
-	if err != nil {
-		return "", err
-	}
-	if len(ndir) > 2 && isSlash(ndir[0]) && isSlash(ndir[1]) {
-		// dir cannot have \\server\share\path form
-		return "", syscall.EINVAL
-	}
-	return ndir, nil
-}
-
-func volToUpper(ch int) int {
-	if 'a' <= ch && ch <= 'z' {
-		ch += 'A' - 'a'
-	}
-	return ch
-}
-
-func joinExeDirAndFName(dir, p string) (name string, err error) {
-	if len(p) == 0 {
-		return "", syscall.EINVAL
-	}
-	if len(p) > 2 && isSlash(p[0]) && isSlash(p[1]) {
-		// \\server\share\path form
-		return p, nil
-	}
-	if len(p) > 1 && p[1] == ':' {
-		// has drive letter
-		if len(p) == 2 {
-			return "", syscall.EINVAL
-		}
-		if isSlash(p[2]) {
-			return p, nil
-		} else {
-			d, err := normalizeDir(dir)
-			if err != nil {
-				return "", err
-			}
-			if volToUpper(int(p[0])) == volToUpper(int(d[0])) {
-				return FullPath(d + "\\" + p[2:])
-			} else {
-				return FullPath(p)
-			}
-		}
-	} else {
-		// no drive letter
-		d, err := normalizeDir(dir)
-		if err != nil {
-			return "", err
-		}
-		if isSlash(p[0]) {
-			return FullPath(d[:2] + p)
-		} else {
-			return FullPath(d + "\\" + p)
-		}
-	}
-	// we shouldn't be here
-	return "", syscall.EINVAL
-}
-
-type ProcAttr struct {
-	Dir   string
-	Env   []string
-	Files []uintptr
-	Sys   *SysProcAttr
-}
-
-type SysProcAttr struct {
-	HideWindow    bool
-	CmdLine       string // used if non-empty, else the windows command line is built by escaping the arguments passed to StartProcess
-	CreationFlags uint32
-}
-
-var zeroProcAttr ProcAttr
-var zeroSysProcAttr SysProcAttr
-
-func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
-	if len(argv0) == 0 {
-		return 0, 0, syscall.EWINDOWS
-	}
-	if attr == nil {
-		attr = &zeroProcAttr
-	}
-	sys := attr.Sys
-	if sys == nil {
-		sys = &zeroSysProcAttr
-	}
-
-	if len(attr.Files) > 3 {
-		return 0, 0, syscall.EWINDOWS
-	}
-
-	if len(attr.Dir) != 0 {
-		// StartProcess assumes that argv0 is relative to attr.Dir,
-		// because it implies Chdir(attr.Dir) before executing argv0.
-		// Windows CreateProcess assumes the opposite: it looks for
-		// argv0 relative to the current directory, and, only once the new
-		// process is started, it does Chdir(attr.Dir). We are adjusting
-		// for that difference here by making argv0 absolute.
-		var err error
-		argv0, err = joinExeDirAndFName(attr.Dir, argv0)
-		if err != nil {
-			return 0, 0, err
-		}
-	}
-	argv0p, err := UTF16PtrFromString(argv0)
-	if err != nil {
-		return 0, 0, err
-	}
-
-	var cmdline string
-	// Windows CreateProcess takes the command line as a single string:
-	// use attr.CmdLine if set, else build the command line by escaping
-	// and joining each argument with spaces
-	if sys.CmdLine != "" {
-		cmdline = sys.CmdLine
-	} else {
-		cmdline = makeCmdLine(argv)
-	}
-
-	var argvp *uint16
-	if len(cmdline) != 0 {
-		argvp, err = UTF16PtrFromString(cmdline)
-		if err != nil {
-			return 0, 0, err
-		}
-	}
-
-	var dirp *uint16
-	if len(attr.Dir) != 0 {
-		dirp, err = UTF16PtrFromString(attr.Dir)
-		if err != nil {
-			return 0, 0, err
-		}
-	}
-
-	// Acquire the fork lock so that no other threads
-	// create new fds that are not yet close-on-exec
-	// before we fork.
-	ForkLock.Lock()
-	defer ForkLock.Unlock()
-
-	p, _ := GetCurrentProcess()
-	fd := make([]Handle, len(attr.Files))
-	for i := range attr.Files {
-		if attr.Files[i] > 0 {
-			err := DuplicateHandle(p, Handle(attr.Files[i]), p, &fd[i], 0, true, DUPLICATE_SAME_ACCESS)
-			if err != nil {
-				return 0, 0, err
-			}
-			defer CloseHandle(Handle(fd[i]))
-		}
-	}
-	si := new(StartupInfo)
-	si.Cb = uint32(unsafe.Sizeof(*si))
-	si.Flags = STARTF_USESTDHANDLES
-	if sys.HideWindow {
-		si.Flags |= STARTF_USESHOWWINDOW
-		si.ShowWindow = SW_HIDE
-	}
-	si.StdInput = fd[0]
-	si.StdOutput = fd[1]
-	si.StdErr = fd[2]
-
-	pi := new(ProcessInformation)
-
-	flags := sys.CreationFlags | CREATE_UNICODE_ENVIRONMENT
-	err = CreateProcess(argv0p, argvp, nil, nil, true, flags, createEnvBlock(attr.Env), dirp, si, pi)
-	if err != nil {
-		return 0, 0, err
-	}
-	defer CloseHandle(Handle(pi.Thread))
-
-	return int(pi.ProcessId), uintptr(pi.Process), nil
-}
-
-func Exec(argv0 string, argv []string, envv []string) (err error) {
-	return syscall.EWINDOWS
-}