config: fix parsing of file permissions

The file permissions can be specified (unfortunately) as a string or an
octal integer. During the normalization step, every field is
unmarshalled into an interface{}. String types are kept in tact but
integers are converted to decimal integers. If the raw config
represented the permissions as an octal, it would be converted to
decimal _before_ it was saved to RawFilePermissions. Permissions() would
then try to convert it again, assuming it was an octal. The new behavior
doesn't assume the radix of the number, allowing decimal and octal
input.

system/file.go

@@ -17,7 +17,6 @@
 package system
 
 import (
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -39,10 +38,10 @@ func (f *File) Permissions() (os.FileMode, error) {
 		return os.FileMode(0644), nil
 	}
 
-	// Parse string representation of file mode as octal
-	perm, err := strconv.ParseInt(f.RawFilePermissions, 8, 32)
+	// Parse string representation of file mode as integer
+	perm, err := strconv.ParseInt(f.RawFilePermissions, 0, 32)
 	if err != nil {
-		return 0, errors.New("Unable to parse file permissions as octal integer")
+		return 0, fmt.Errorf("Unable to parse file permissions %q as integer", f.RawFilePermissions)
 	}
 	return os.FileMode(perm), nil
 }

system/file_test.go

@@ -85,6 +85,38 @@ func TestWriteFileInvalidPermission(t *testing.T) {
 	}
 }
 
+func TestDecimalFilePermissions(t *testing.T) {
+	dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
+	if err != nil {
+		t.Fatalf("Unable to create tempdir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	fn := "foo"
+	fullPath := path.Join(dir, fn)
+
+	wf := File{config.File{
+		Path:               fn,
+		RawFilePermissions: "484", // Decimal representation of 0744
+	}}
+
+	path, err := WriteFile(&wf, dir)
+	if err != nil {
+		t.Fatalf("Processing of WriteFile failed: %v", err)
+	} else if path != fullPath {
+		t.Fatalf("WriteFile returned bad path: want %s, got %s", fullPath, path)
+	}
+
+	fi, err := os.Stat(fullPath)
+	if err != nil {
+		t.Fatalf("Unable to stat file: %v", err)
+	}
+
+	if fi.Mode() != os.FileMode(0744) {
+		t.Errorf("File has incorrect mode: %v", fi.Mode())
+	}
+}
+
 func TestWriteFilePermissions(t *testing.T) {
 	dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
 	if err != nil {