syscallcompat: move quirks logic here & fix darwin

We need to look at f_fstypename acc. to
https://stackoverflow.com/a/52299141/1380267 :

> As filesystem type numbers are now assigned at runtime in
> recent versions of MacOS, you must use f_fstypename to
> determine the type.

https://github.com/rfjakob/gocryptfs/issues/585

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/root_test/root_test.go b/tests/root_test/root_test.go
index 8547e4e..e68f86a 100644
--- a/tests/root_test/root_test.go
+++ b/tests/root_test/root_test.go
@@ -12,6 +12,8 @@ import (
 	"syscall"
 	"testing"
 
+	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
+
 	"golang.org/x/sys/unix"
 
 	"github.com/rfjakob/gocryptfs/tests/test_helpers"
@@ -311,3 +313,50 @@ func TestAcl(t *testing.T) {
 		dumpAcl()
 	}
 }
+
+// TestBtrfsQuirks needs root permissions because it creates a loop disk
+func TestBtrfsQuirks(t *testing.T) {
+	if os.Getuid() != 0 {
+		t.Skip("must run as root")
+	}
+
+	img := filepath.Join(test_helpers.TmpDir, t.Name()+".img")
+	f, err := os.Create(img)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	// minimum size for each btrfs device is 114294784
+	err = f.Truncate(200 * 1024 * 1024)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Format as Btrfs
+	cmd := exec.Command("mkfs.btrfs", img)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Log(string(out))
+		t.Fatal(err)
+	}
+
+	// Mount
+	mnt := img + ".mnt"
+	err = os.Mkdir(mnt, 0600)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cmd = exec.Command("mount", img, mnt)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Log(string(out))
+		t.Fatal(err)
+	}
+	defer syscall.Unlink(img)
+	defer syscall.Unmount(mnt, 0)
+
+	quirk := syscallcompat.DetectQuirks(mnt)
+	if quirk != syscallcompat.QuirkBrokenFalloc {
+		t.Errorf("wrong quirk: %v", quirk)
+	}
+}