duplicate_test.go RawHistoryFolder

1package fdwait
2
3import (
4	"golang.org/x/sys/unix"
5	"testing"
6	"time"
7)
8
9// Epoll retains a registration after its fd closes if another descriptor
10// still refers to the same open file description.
11func TestRemovedDuplicatedDescriptorDoesNotKeepPollReadable(t *testing.T) {
12	p, err := New()
13	if err != nil {
14		t.Fatal(err)
15	}
16	defer p.Close()
17	old, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
18	if err != nil {
19		t.Fatal(err)
20	}
21	dup, err := unix.Dup(old)
22	if err != nil {
23		unix.Close(old)
24		t.Fatal(err)
25	}
26	defer unix.Close(dup)
27	if _, err := p.Poll([]unix.PollFd{{Fd: int32(old), Events: unix.POLLIN}}, 1); err != nil {
28		t.Fatal(err)
29	}
30	// Create the next descriptor before closing old so its number is not
31	// reused. This leaves an old epoll registration with no usable fd.
32	fresh, err := unix.Eventfd(0, unix.EFD_NONBLOCK|unix.EFD_CLOEXEC)
33	if err != nil {
34		t.Fatal(err)
35	}
36	defer unix.Close(fresh)
37	unix.Close(old)
38	if _, err := unix.Write(dup, []byte{1, 0, 0, 0, 0, 0, 0, 0}); err != nil {
39		t.Fatal(err)
40	}
41	if err := p.raw.Control(func(ep uintptr) {
42		var events [1]unix.EpollEvent
43		if n, err := unix.EpollWait(int(ep), events[:], 0); n != 0 || err != nil {
44			t.Errorf("closed watched descriptor still makes epoll readable: %d %v", n, err)
45		}
46	}); err != nil {
47		t.Fatal(err)
48	}
49	done := make(chan error, 1)
50	go func() { _, err := p.Poll([]unix.PollFd{{Fd: int32(fresh), Events: unix.POLLIN}}, 20); done <- err }()
51	select {
52	case err := <-done:
53		if err != nil {
54			t.Fatal(err)
55		}
56	case <-time.After(time.Second):
57		p.Close()
58		t.Fatal("stale epoll readiness prevents timeout")
59	}
60}