//go:build linux

package layout

import (
	"errors"
	"os"
	"path/filepath"
	"testing"
	"time"

	"golang.org/x/sys/unix"
)

// TestReadJournalRefusesASymlinkAndAFIFO_FIFO is the FIFO half of
// TestReadJournalRefusesASymlinkAndAFIFO: /data/layout is agent-owned,
// but a flat tenant shares the agent's uid during the transition and can
// plant a FIFO there in place of a journal. ReadJournal must refuse it
// rather than block on the open. Run with a timeout so a regression here
// fails the test instead of wedging it.
func TestReadJournalRefusesASymlinkAndAFIFO_FIFO(t *testing.T) {
	dd := t.TempDir()
	dir := filepath.Join(dd, "layout")
	if err := os.MkdirAll(dir, 0o700); err != nil {
		t.Fatal(err)
	}
	if err := unix.Mkfifo(filepath.Join(dir, "h.example.com.json"), 0o600); err != nil {
		t.Fatalf("Mkfifo: %v", err)
	}
	done := make(chan error, 1)
	go func() {
		_, _, err := ReadJournal(dd, "h.example.com")
		done <- err
	}()
	select {
	case err := <-done:
		if err == nil {
			t.Error("a FIFO planted as a journal was read")
		}
		if errors.Is(err, os.ErrNotExist) {
			t.Errorf("FIFO reported as absent rather than refused: %v", err)
		}
	case <-time.After(2 * time.Second):
		t.Fatal("ReadJournal blocked on a FIFO instead of refusing it")
	}
}