Initial transfer.

common/system/prober/probe_windows.go

Index: common/system/prober/probe_windows.go
diff --git a/common/system/prober/probe_windows.go b/common/system/prober/probe_windows.go
new file mode 100644
index 0000000000000000000000000000000000000000..7542f2d7309e41a48a1494ab777bdf1d2116c646
--- /dev/null
+++ b/common/system/prober/probe_windows.go
@@ -0,0 +1,82 @@
+// Copyright 2017 The LUCI 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 prober
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/luci/luci-go/common/errors"
+	"github.com/luci/luci-go/common/system/environ"
+)
+
+func chkStat(file string) error {
+	d, err := os.Stat(file)
+	if err != nil {
+		return err
+	}
+	if d.IsDir() {
+		return os.ErrPermission
+	}
+	return nil
+}
+
+func hasExt(file string) bool {
+	i := strings.LastIndex(file, ".")
+	if i < 0 {
+		return false
+	}
+	return strings.LastIndexAny(file, `:\/`) < i
+}
+
+func findExecutable(file string, exts []string) (string, error) {
+	if len(exts) == 0 {
+		return file, chkStat(file)
+	}
+	if hasExt(file) {
+		if chkStat(file) == nil {
+			return file, nil
+		}
+	}
+	for _, e := range exts {
+		if f := file + e; chkStat(f) == nil {
+			return f, nil
+		}
+	}
+	return "", os.ErrNotExist
+}
+
+// findInDir is a paraphrased and trimmed version of "exec.LookPath"
+// (for Windows),
+//
+// Copied from:
+// https://github.com/golang/go/blob/d234f9a75413fdae7643e4be9471b4aeccf02478/src/os/exec/lp_windows.go
+//
+// Modified to:
+//	- Use a supplied "dir" instead of scanning through PATH.
+//	- Not consider cases where "file" is an absolute path
+//	- Ignore the possibility that "file" may be in the CWD; only look in "dir".
+func findInDir(file, dir string, env environ.Env) (string, error) {
+	var exts []string
+	if x, ok := env.Get(`PATHEXT`); ok {
+		for _, e := range strings.Split(strings.ToLower(x), `;`) {
+			if e == "" {
+				continue
+			}
+			if e[0] != '.' {
+				e = "." + e
+			}
+			exts = append(exts, e)
+		}
+	} else {
+		exts = []string{".com", ".exe", ".bat", ".cmd"}
+	}
+
+	if f, err := findExecutable(filepath.Join(dir, file), exts); err == nil {
+		return f, nil
+	}
+	return "", errors.New("not found")
+}