Implement controlled app launch (T-401)

app-win7/platform/windows/process.go

@@ -0,0 +1,56 @@
+package windows
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+// processSnapshot is deliberately small so the matching invariant can be
+// tested without a Windows host. NextImagePath returns more=false only after a
+// successful end-of-snapshot; any enumeration or image-path failure is an
+// error, rather than evidence that the target is not running.
+type processSnapshot interface {
+	NextImagePath() (path string, more bool, err error)
+	Close() error
+}
+
+type processSnapshotFactory func() (processSnapshot, error)
+
+func entrypointIsRunning(entrypoint string, newSnapshot processSnapshotFactory) (bool, error) {
+	target, err := canonicalProcessPath(entrypoint)
+	if err != nil {
+		return false, fmt.Errorf("canonicalize target entrypoint: %w", err)
+	}
+
+	snapshot, err := newSnapshot()
+	if err != nil {
+		return false, fmt.Errorf("create process snapshot: %w", err)
+	}
+	defer snapshot.Close()
+
+	for {
+		path, more, err := snapshot.NextImagePath()
+		if err != nil {
+			return false, fmt.Errorf("enumerate process image path: %w", err)
+		}
+		if !more {
+			return false, nil
+		}
+		candidate, err := canonicalProcessPath(path)
+		if err != nil {
+			return false, fmt.Errorf("canonicalize process image path: %w", err)
+		}
+		if strings.EqualFold(target, candidate) {
+			return true, nil
+		}
+	}
+}
+
+func canonicalProcessPath(path string) (string, error) {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+	return filepath.Clean(abs), nil
+}