fs: Include filename in mknod errors

internal/fs/mknod_unix.go

@@ -3,8 +3,16 @@
 
 package fs
 
-import "golang.org/x/sys/unix"
+import (
+	"os"
 
-func mknod(path string, mode uint32, dev uint64) (err error) {
+	"golang.org/x/sys/unix"
-	return unix.Mknod(path, mode, int(dev))
+)
+
+func mknod(path string, mode uint32, dev uint64) error {
+	err := unix.Mknod(path, mode, int(dev))
+	if err != nil {
+		err = &os.PathError{Op: "mknod", Path: path, Err: err}
+	}
+	return err
 }

internal/fs/node_freebsd.go

@@ -3,12 +3,19 @@
 
 package fs
 
-import "syscall"
+import (
+	"os"
+	"syscall"
+)
 
 func nodeRestoreSymlinkTimestamps(path string, utimes [2]syscall.Timespec) error {
 	return nil
 }
 
-func mknod(path string, mode uint32, dev uint64) (err error) {
+func mknod(path string, mode uint32, dev uint64) error {
-	return syscall.Mknod(path, mode, dev)
+	err := syscall.Mknod(path, mode, dev)
+	if err != nil {
+		err = &os.PathError{Op: "mknod", Path: path, Err: err}
+	}
+	return err
 }

internal/fs/node_unix_test.go

@@ -8,9 +8,11 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 	"syscall"
 	"testing"
 
+	"github.com/restic/restic/internal/errors"
 	"github.com/restic/restic/internal/restic"
 	rtest "github.com/restic/restic/internal/test"
 )
@@ -134,3 +136,12 @@ func TestNodeFromFileInfo(t *testing.T) {
 		})
 	}
 }
+
+func TestMknodError(t *testing.T) {
+	d := t.TempDir()
+	// Call mkfifo, which calls mknod, as mknod may give
+	// "operation not permitted" on Mac.
+	err := mkfifo(d, 0)
+	rtest.Assert(t, errors.Is(err, os.ErrExist), "want ErrExist, got %q", err)
+	rtest.Assert(t, strings.Contains(err.Error(), d), "filename not in %q", err)
+}