package sys

import (
	"runtime"
	"testing"
	"unsafe"

	"github.com/cilium/ebpf/internal/unix"

	qt "github.com/frankban/quicktest"
)

func TestSigset(t *testing.T) {
	const maxSignal = unix.Signal(unsafe.Sizeof(unix.Sigset_t{}) * 8)

	// Type-infer a sigset word. This is a typed uint of 32 or 64 bits depending
	// on the target architecture, so we can't use an untyped uint.
	zero := unix.Sigset_t{}.Val[0]
	words := len(unix.Sigset_t{}.Val)

	var want, got unix.Sigset_t
	// Flip the first bit of the first word.
	if err := sigsetAdd(&got, 1); err != nil {
		t.Fatal(err)
	}
	want.Val[0] = 1
	if want != got {
		t.Fatalf("expected first word to be 0x%x, got: 0x%x", want, got)
	}

	// And the last bit of the last word.
	if err := sigsetAdd(&got, maxSignal); err != nil {
		t.Fatal(err)
	}
	want.Val[words-1] = ^(^zero >> 1)
	if want != got {
		t.Fatalf("expected last word to be 0x%x, got: 0x%x", want, got)
	}

	if err := sigsetAdd(&got, maxSignal+1); err == nil {
		t.Fatal("expected out-of-bounds add to be rejected")
	}
	if err := sigsetAdd(&got, -1); err == nil {
		t.Fatal("expected negative signal to be rejected")
	}
}

func TestProfilerSignal(t *testing.T) {
	// Additional goroutine lock to make the PthreadSigmask below execute on the
	// same OS thread as the functions under test. UnlockOSThread needs to be
	// called as many times as LockOSThread to unlock the goroutine.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	var old unix.Sigset_t
	if err := unix.PthreadSigmask(0, nil, &old); err != nil {
		t.Fatal("get sigmask:", err)
	}

	maskProfilerSignal()

	var have unix.Sigset_t
	if err := unix.PthreadSigmask(0, nil, &have); err != nil {
		t.Fatal("get sigmask:", err)
	}

	want := have
	qt.Assert(t, sigsetAdd(&want, unix.SIGPROF), qt.IsNil)
	qt.Assert(t, have, qt.Equals, want)

	unmaskProfilerSignal()

	if err := unix.PthreadSigmask(0, nil, &have); err != nil {
		t.Fatal("get sigmask:", err)
	}

	qt.Assert(t, have, qt.Equals, old)
}