package host

import (
	"github.com/carlosframework/platform/internal/rootstate"
	"golang.org/x/sys/unix"
	"os"
	"testing"
)

func TestPlan14PersistentChrootMountBoundary(t *testing.T) {
	if !plan14RootFixture(t) {
		return
	}
	for _, p := range []string{"/data", "/view"} {
		if e := os.Mkdir(p, 0755); e != nil {
			t.Fatal(e)
		}
	}
	if e := unix.Mount("/data", "/view", "", unix.MS_BIND, ""); e != nil {
		t.Fatal(e)
	}
	defer unix.Unmount("/view", 0)
	f, e := os.Open("/view")
	if e != nil {
		t.Fatal(e)
	}
	defer f.Close()
	before, e := rootstate.ObjectIdentity(f)
	if e != nil || before.MountLineage == "" {
		t.Fatal(before, e)
	}
	if e := unix.Mount("/view", "/view", "", unix.MS_BIND, ""); e != nil {
		t.Fatal(e)
	}
	second, e := os.Open("/view")
	if e != nil {
		t.Fatal(e)
	}
	after, e := rootstate.ObjectIdentity(second)
	second.Close()
	unmount := unix.Unmount("/view", 0)
	if e != nil || unmount != nil || before.Same(after) {
		t.Fatal("substituted mount", e, unmount, before, after)
	}
	restored, e := rootstate.ObjectIdentity(f)
	if e != nil || !before.Same(restored) {
		t.Fatal("restored mount", e)
	}
	if err := unix.Unmount("/view", unix.MNT_DETACH); err != nil {
		t.Fatal(err)
	}
	if err := unix.Mount("/data", "/view", "", unix.MS_BIND, ""); err != nil {
		t.Fatal(err)
	}
	replacement, err := os.Open("/view")
	if err != nil {
		t.Fatal(err)
	}
	replaced, err := rootstate.ObjectIdentity(replacement)
	replacement.Close()
	if err != nil || replaced.MountUnique == before.MountUnique || !replaced.SameMountNamespace(before) || replaced.MountLineage != before.MountLineage || replaced.Filesystem != before.Filesystem || replaced.Handle != before.Handle || replaced.Inode != before.Inode {
		t.Fatal("replacement did not preserve geometry and persistent object", before, replaced, err)
	}
	if before.Same(replaced) {
		t.Fatal("replacement mount with unchanged geometry accepted")
	}
	replaced.Mount = before.Mount
	if before.Same(replaced) {
		t.Fatal("replacement mount accepted with a recycled legacy number")
	}
	for _, path := range []string{"/source", "/parent", "/parent/view"} {
		if err := os.Mkdir(path, 0755); err != nil {
			t.Fatal(err)
		}
	}
	if err := unix.Mount("/source", "/parent/view", "", unix.MS_BIND, ""); err != nil {
		t.Fatal(err)
	}
	defer unix.Unmount("/parent/view", 0)
	capture := func() rootstate.FileIdentity {
		f, err := os.Open("/parent/view")
		if err != nil {
			t.Fatal(err)
		}
		defer f.Close()
		id, err := rootstate.ObjectIdentity(f)
		if err != nil {
			t.Fatal(err)
		}
		return id
	}
	child := capture()
	if err := unix.Mount("/parent", "/parent", "", unix.MS_BIND|unix.MS_REC, ""); err != nil {
		t.Fatal(err)
	}
	defer unix.Unmount("/parent", unix.MNT_DETACH)
	rebound := capture()
	if child.MountRoot != rebound.MountRoot || child.MountPoint != rebound.MountPoint || child.Filesystem != rebound.Filesystem || child.Handle != rebound.Handle || child.Inode != rebound.Inode {
		t.Fatal("recursive bind changed the child fixture", child, rebound)
	}
	if child.Same(rebound) || rebound.Same(child) {
		t.Fatal("recursive ancestor substitution accepted")
	}
}