feat(prebuild): make prebuild available as an external package.

Usefull for downstream repo.

pkg/prebuild/tools.go

@@ -0,0 +1,78 @@
+// apparmor.d - Full set of apparmor profiles
+// Copyright (C) 2023 Alexandre Pujol <alexandre@pujol.io>
+// SPDX-License-Identifier: GPL-2.0-only
+
+package prebuild
+
+import (
+	"os"
+	"strings"
+
+	"github.com/arduino/go-paths-helper"
+	"github.com/roddhjav/apparmor.d/pkg/aa"
+	"golang.org/x/exp/slices"
+)
+
+var (
+	osReleaseFile   = "/etc/os-release"
+	firstPartyDists = []string{"arch", "debian", "ubuntu", "opensuse", "whonix"}
+)
+
+func getSupportedDistribution() string {
+	dist, present := os.LookupEnv("DISTRIBUTION")
+	if present {
+		return dist
+	}
+
+	lines, err := paths.New(osReleaseFile).ReadFileAsLines()
+	if err != nil {
+		panic(err)
+	}
+
+	id := ""
+	id_like := ""
+	for _, line := range lines {
+		item := strings.Split(line, "=")
+		if item[0] == "ID" {
+			id = strings.Split(strings.Trim(item[1], "\""), " ")[0]
+		} else if item[0] == "ID_LIKE" {
+			id_like = strings.Split(strings.Trim(item[1], "\""), " ")[0]
+		}
+	}
+
+	if slices.Contains(firstPartyDists, id) {
+		return id
+	} else if slices.Contains(firstPartyDists, id_like) {
+		return id_like
+	}
+	return id
+}
+
+func setLibexec(libexec string) error {
+	aa.Tunables["libexec"] = []string{libexec}
+	file, err := RootApparmord.Join("tunables", "multiarch.d", "apparmor.d").Append()
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	_, err = file.WriteString(`@{libexec}=` + libexec)
+	return err
+}
+
+func copyTo(src *paths.Path, dst *paths.Path) error {
+	files, err := src.ReadDirRecursiveFiltered(nil, paths.FilterOutDirectories())
+	if err != nil {
+		return err
+	}
+	for _, file := range files {
+		destination, err := file.RelFrom(src)
+		if err != nil {
+			return err
+		}
+		destination = dst.JoinPath(destination)
+		if err := file.CopyTo(destination); err != nil {
+			return err
+		}
+	}
+	return nil
+}