//go:build linux

package dbreads

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

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

func me() (uint32, error) { return uint32(os.Getuid()), nil }

func other() (uint32, error) { return uint32(os.Getuid()) + 1, nil }

func socketpairFile(t *testing.T, typ int) (*os.File, *os.File) {
	t.Helper()
	fds, err := unix.Socketpair(unix.AF_UNIX, typ, 0)
	if err != nil {
		t.Fatal(err)
	}
	a, b := os.NewFile(uintptr(fds[0]), "a"), os.NewFile(uintptr(fds[1]), "b")
	t.Cleanup(func() { a.Close(); b.Close() })
	return a, b
}

// The worker runs only on a connected unix stream socket whose peer is the
// agent's user (spec §8.3): it cannot be started by hand or pointed at a
// file.
func TestStdinConnRefusesWhatIsNotTheAgentsSocket(t *testing.T) {
	t.Parallel()
	file, err := os.Create(filepath.Join(t.TempDir(), "f"))
	if err != nil {
		t.Fatal(err)
	}
	defer file.Close()
	r, w, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}
	defer r.Close()
	defer w.Close()
	dgram, _ := socketpairFile(t, unix.SOCK_DGRAM)
	stream, _ := socketpairFile(t, unix.SOCK_STREAM)
	for name, f := range map[string]*os.File{"a file": file, "a pipe": r, "a datagram socket": dgram} {
		if _, err := StdinConn(f, me); err == nil {
			t.Errorf("%s accepted", name)
		}
	}
	if _, err := StdinConn(stream, other); err == nil {
		t.Fatal("a peer that is not the agent's user accepted")
	}
	c, err := StdinConn(stream, me)
	if err != nil {
		t.Fatal(err)
	}
	c.Close()
}