1 files changed, 422 insertions, 0 deletions
diff --git a/src/syscall/exec_windows.go b/src/syscall/exec_windows.go
new file mode 100644
index 0000000..9d10d6a
--- /dev/null
+++ b/src/syscall/exec_windows.go
@@ -0,0 +1,422 @@
+// 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.
+
+// Fork, exec, wait, etc.
+
+package syscall
+
+import (
+	"runtime"
+	"sync"
+	"unicode/utf16"
+	"unsafe"
+)
+
+var ForkLock sync.RWMutex
+
+// EscapeArg rewrites command line argument s as prescribed
+// in https://msdn.microsoft.com/en-us/library/ms880421.
+// This function returns "" (2 double quotes) if s is empty.
+// Alternatively, these transformations are done:
+// - every back slash (\) is doubled, but only if immediately
+//   followed by double quote (");
+// - every double quote (") is escaped by back slash (\);
+// - finally, s is wrapped with double quotes (arg -> "arg"),
+//   but only if there is space or tab inside s.
+func EscapeArg(s string) string {
+	if len(s) == 0 {
+		return `""`
+	}
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '"', '\\', ' ', '\t':
+			// Some escaping required.
+			b := make([]byte, 0, len(s)+2)
+			b = appendEscapeArg(b, s)
+			return string(b)
+		}
+	}
+	return s
+}
+
+// appendEscapeArg escapes the string s, as per escapeArg,
+// appends the result to b, and returns the updated slice.
+func appendEscapeArg(b []byte, s string) []byte {
+	if len(s) == 0 {
+		return append(b, `""`...)
+	}
+
+	needsBackslash := false
+	hasSpace := false
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '"', '\\':
+			needsBackslash = true
+		case ' ', '\t':
+			hasSpace = true
+		}
+	}
+
+	if !needsBackslash && !hasSpace {
+		// No special handling required; normal case.
+		return append(b, s...)
+	}
+	if !needsBackslash {
+		// hasSpace is true, so we need to quote the string.
+		b = append(b, '"')
+		b = append(b, s...)
+		return append(b, '"')
+	}
+
+	if hasSpace {
+		b = append(b, '"')
+	}
+	slashes := 0
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		switch c {
+		default:
+			slashes = 0
+		case '\\':
+			slashes++
+		case '"':
+			for ; slashes > 0; slashes-- {
+				b = append(b, '\\')
+			}
+			b = append(b, '\\')
+		}
+		b = append(b, c)
+	}
+	if hasSpace {
+		for ; slashes > 0; slashes-- {
+			b = append(b, '\\')
+		}
+		b = append(b, '"')
+	}
+
+	return b
+}
+
+// makeCmdLine builds a command line out of args by escaping "special"
+// characters and joining the arguments with spaces.
+func makeCmdLine(args []string) string {
+	var b []byte
+	for _, v := range args {
+		if len(b) > 0 {
+			b = append(b, ' ')
+		}
+		b = appendEscapeArg(b, v)
+	}
+	return string(b)
+}
+
+// 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)
+	if err != nil {
+		return "", err
+	}
+	n := uint32(100)
+	for {
+		buf := make([]uint16, n)
+		n, err = GetFullPathName(p, uint32(len(buf)), &buf[0], nil)
+		if err != nil {
+			return "", err
+		}
+		if n <= uint32(len(buf)) {
+			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 "", 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 "", 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 "", 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)
+		}
+	}
+}
+
+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
+	Token                      Token               // if set, runs new process in the security context represented by the token
+	ProcessAttributes          *SecurityAttributes // if set, applies these security attributes as the descriptor for the new process
+	ThreadAttributes           *SecurityAttributes // if set, applies these security attributes as the descriptor for the main thread of the new process
+	NoInheritHandles           bool                // if set, each inheritable handle in the calling process is not inherited by the new process
+	AdditionalInheritedHandles []Handle            // a list of additional handles, already marked as inheritable, that will be inherited by the new process
+	ParentProcess              Handle              // if non-zero, the new process regards the process given by this handle as its parent process, and AdditionalInheritedHandles, if set, should exist in this parent process
+}
+
+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, EWINDOWS
+	}
+	if attr == nil {
+		attr = &zeroProcAttr
+	}
+	sys := attr.Sys
+	if sys == nil {
+		sys = &zeroSysProcAttr
+	}
+
+	if len(attr.Files) > 3 {
+		return 0, 0, EWINDOWS
+	}
+	if len(attr.Files) < 3 {
+		return 0, 0, EINVAL
+	}
+
+	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
+		}
+	}
+
+	var maj, min, build uint32
+	rtlGetNtVersionNumbers(&maj, &min, &build)
+	isWin7 := maj < 6 || (maj == 6 && min <= 1)
+	// NT kernel handles are divisible by 4, with the bottom 3 bits left as
+	// a tag. The fully set tag correlates with the types of handles we're
+	// concerned about here.  Except, the kernel will interpret some
+	// special handle values, like -1, -2, and so forth, so kernelbase.dll
+	// checks to see that those bottom three bits are checked, but that top
+	// bit is not checked.
+	isLegacyWin7ConsoleHandle := func(handle Handle) bool { return isWin7 && handle&0x10000003 == 3 }
+
+	p, _ := GetCurrentProcess()
+	parentProcess := p
+	if sys.ParentProcess != 0 {
+		parentProcess = sys.ParentProcess
+	}
+	fd := make([]Handle, len(attr.Files))
+	for i := range attr.Files {
+		if attr.Files[i] > 0 {
+			destinationProcessHandle := parentProcess
+
+			// On Windows 7, console handles aren't real handles, and can only be duplicated
+			// into the current process, not a parent one, which amounts to the same thing.
+			if parentProcess != p && isLegacyWin7ConsoleHandle(Handle(attr.Files[i])) {
+				destinationProcessHandle = p
+			}
+
+			err := DuplicateHandle(p, Handle(attr.Files[i]), destinationProcessHandle, &fd[i], 0, true, DUPLICATE_SAME_ACCESS)
+			if err != nil {
+				return 0, 0, err
+			}
+			defer DuplicateHandle(parentProcess, fd[i], 0, nil, 0, false, DUPLICATE_CLOSE_SOURCE)
+		}
+	}
+	si := new(_STARTUPINFOEXW)
+	si.ProcThreadAttributeList, err = newProcThreadAttributeList(2)
+	if err != nil {
+		return 0, 0, err
+	}
+	defer deleteProcThreadAttributeList(si.ProcThreadAttributeList)
+	si.Cb = uint32(unsafe.Sizeof(*si))
+	si.Flags = STARTF_USESTDHANDLES
+	if sys.HideWindow {
+		si.Flags |= STARTF_USESHOWWINDOW
+		si.ShowWindow = SW_HIDE
+	}
+	if sys.ParentProcess != 0 {
+		err = updateProcThreadAttribute(si.ProcThreadAttributeList, 0, _PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, unsafe.Pointer(&sys.ParentProcess), unsafe.Sizeof(sys.ParentProcess), nil, nil)
+		if err != nil {
+			return 0, 0, err
+		}
+	}
+	si.StdInput = fd[0]
+	si.StdOutput = fd[1]
+	si.StdErr = fd[2]
+
+	fd = append(fd, sys.AdditionalInheritedHandles...)
+
+	// On Windows 7, console handles aren't real handles, so don't pass them
+	// through to PROC_THREAD_ATTRIBUTE_HANDLE_LIST.
+	for i := range fd {
+		if isLegacyWin7ConsoleHandle(fd[i]) {
+			fd[i] = 0
+		}
+	}
+
+	// The presence of a NULL handle in the list is enough to cause PROC_THREAD_ATTRIBUTE_HANDLE_LIST
+	// to treat the entire list as empty, so remove NULL handles.
+	j := 0
+	for i := range fd {
+		if fd[i] != 0 {
+			fd[j] = fd[i]
+			j++
+		}
+	}
+	fd = fd[:j]
+
+	willInheritHandles := len(fd) > 0 && !sys.NoInheritHandles
+
+	// Do not accidentally inherit more than these handles.
+	if willInheritHandles {
+		err = updateProcThreadAttribute(si.ProcThreadAttributeList, 0, _PROC_THREAD_ATTRIBUTE_HANDLE_LIST, unsafe.Pointer(&fd[0]), uintptr(len(fd))*unsafe.Sizeof(fd[0]), nil, nil)
+		if err != nil {
+			return 0, 0, err
+		}
+	}
+
+	pi := new(ProcessInformation)
+	flags := sys.CreationFlags | CREATE_UNICODE_ENVIRONMENT | _EXTENDED_STARTUPINFO_PRESENT
+	if sys.Token != 0 {
+		err = CreateProcessAsUser(sys.Token, argv0p, argvp, sys.ProcessAttributes, sys.ThreadAttributes, willInheritHandles, flags, createEnvBlock(attr.Env), dirp, &si.StartupInfo, pi)
+	} else {
+		err = CreateProcess(argv0p, argvp, sys.ProcessAttributes, sys.ThreadAttributes, willInheritHandles, flags, createEnvBlock(attr.Env), dirp, &si.StartupInfo, pi)
+	}
+	if err != nil {
+		return 0, 0, err
+	}
+	defer CloseHandle(Handle(pi.Thread))
+	runtime.KeepAlive(fd)
+	runtime.KeepAlive(sys)
+
+	return int(pi.ProcessId), uintptr(pi.Process), nil
+}
+
+func Exec(argv0 string, argv []string, envv []string) (err error) {
+	return EWINDOWS
+}