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
 }

util/executable.go

@@ -0,0 +1,55 @@
+// Mgmt
+// Copyright (C) 2013-2024+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+// Additional permission under GNU GPL version 3 section 7
+//
+// If you modify this program, or any covered work, by linking or combining it
+// with embedded mcl code and modules (and that the embedded mcl code and
+// modules which link with this program, contain a copy of their source code in
+// the authoritative form) containing parts covered by the terms of any other
+// license, the licensors of this program grant you additional permission to
+// convey the resulting work. Furthermore, the licensors of this program grant
+// the original author, James Shubin, additional permission to update this
+// additional permission if he deems it necessary to achieve the goals of this
+// additional permission.
+
+package util
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// ExecutablePath returns the absolute path to this binary if it can find it.
+func ExecutablePath() (string, error) {
+	p1, err := os.Executable()
+	if err != nil {
+		return "", err
+	}
+
+	p2, err := filepath.EvalSymlinks(p1)
+	if err != nil {
+		return "", err
+	}
+
+	p3, err := filepath.Abs(p2)
+	if err != nil {
+		return "", err
+	}
+
+	return p3, nil
+}