util: Move executable path finding into a helper function

lang/core/deploy/binary_func.go

@@ -31,11 +31,10 @@ package coredeploy
 
 import (
 	"context"
-	"os"
-	"path/filepath"
 
 	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
+	"github.com/purpleidea/mgmt/util"
 )
 
 func init() {
@@ -48,22 +47,12 @@ func init() {
 // BinaryPath returns the path to the binary of this program. This is useful for
 // bootstrapping new machines when we want to get the path to copy it over from.
 func BinaryPath(ctx context.Context, input []types.Value) (types.Value, error) {
-	p1, err := os.Executable()
-	if err != nil {
-		return nil, err
-	}
-
-	p2, err := filepath.EvalSymlinks(p1)
-	if err != nil {
-		return nil, err
-	}
-
-	p3, err := filepath.Abs(p2)
+	p, err := util.ExecutablePath()
 	if err != nil {
 		return nil, err
 	}
 
 	return &types.StrValue{
-		V: p3,
+		V: p,
 	}, nil
 }