Imported Upstream version 1.4upstream/1.4

1 files changed, 340 insertions, 0 deletions

diff --git a/src/syscall/exec_windows.go b/src/syscall/exec_windows.go
new file mode 100644
index 000000000..936aeb577
--- /dev/null
+++ b/src/syscall/exec_windows.go
@@ -0,0 +1,340 @@
+// 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 (
+	"sync"
+	"unicode/utf16"
+	"unsafe"
+)
+
+var ForkLock sync.RWMutex
+
+// EscapeArg rewrites command line argument s as prescribed
+// in http://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 "\"\""
+	}
+	n := len(s)
+	hasSpace := false
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '"', '\\':
+			n++
+		case ' ', '\t':
+			hasSpace = true
+		}
+	}
+	if hasSpace {
+		n += 2
+	}
+	if n == len(s) {
+		return s
+	}
+
+	qs := make([]byte, n)
+	j := 0
+	if hasSpace {
+		qs[j] = '"'
+		j++
+	}
+	slashes := 0
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		default:
+			slashes = 0
+			qs[j] = s[i]
+		case '\\':
+			slashes++
+			qs[j] = s[i]
+		case '"':
+			for ; slashes > 0; slashes-- {
+				qs[j] = '\\'
+				j++
+			}
+			qs[j] = '\\'
+			j++
+			qs[j] = s[i]
+		}
+		j++
+	}
+	if hasSpace {
+		for ; slashes > 0; slashes-- {
+			qs[j] = '\\'
+			j++
+		}
+		qs[j] = '"'
+		j++
+	}
+	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)
+	if err != nil {
+		return "", err
+	}
+	buf := make([]uint16, 100)
+	n, err := GetFullPathName(p, uint32(len(buf)), &buf[0], nil)
+	if err != nil {
+		return "", err
+	}
+	if n > uint32(len(buf)) {
+		// Windows is asking for bigger buffer.
+		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 "", EINVAL
+		}
+	}
+	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)
+		}
+	}
+	// we shouldn't be here
+	return "", 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, 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.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 EWINDOWS
+}