Merge from trunk revision 264932.

From-SVN: r264933

5 files changed, 280 insertions, 114 deletions

diff --git a/libgo/go/net/dnsclient_unix.go b/libgo/go/net/dnsclient_unix.go
index 6ec2f44..3b02930 100644
--- a/libgo/go/net/dnsclient_unix.go
+++ b/libgo/go/net/dnsclient_unix.go
@@ -27,6 +27,20 @@ import (
 	"golang_org/x/net/dns/dnsmessage"
 )
 
+var (
+	errLameReferral              = errors.New("lame referral")
+	errCannotUnmarshalDNSMessage = errors.New("cannot unmarshal DNS message")
+	errCannotMarshalDNSMessage   = errors.New("cannot marshal DNS message")
+	errServerMisbehaving         = errors.New("server misbehaving")
+	errInvalidDNSResponse        = errors.New("invalid DNS response")
+	errNoAnswerFromDNSServer     = errors.New("no answer from DNS server")
+
+	// errServerTemporarlyMisbehaving is like errServerMisbehaving, except
+	// that when it gets translated to a DNSError, the IsTemporary field
+	// gets set to true.
+	errServerTemporarlyMisbehaving = errors.New("server misbehaving")
+)
+
 func newRequest(q dnsmessage.Question) (id uint16, udpReq, tcpReq []byte, err error) {
 	id = uint16(rand.Int()) ^ uint16(time.Now().UnixNano())
 	b := dnsmessage.NewBuilder(make([]byte, 2, 514), dnsmessage.Header{ID: id, RecursionDesired: true})
@@ -105,14 +119,14 @@ func dnsStreamRoundTrip(c Conn, id uint16, query dnsmessage.Question, b []byte)
 	var p dnsmessage.Parser
 	h, err := p.Start(b[:n])
 	if err != nil {
-		return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("cannot unmarshal DNS message")
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
 	}
 	q, err := p.Question()
 	if err != nil {
-		return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("cannot unmarshal DNS message")
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
 	}
 	if !checkResponse(id, query, h, q) {
-		return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("invalid DNS response")
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
 	}
 	return p, h, nil
 }
@@ -122,7 +136,7 @@ func (r *Resolver) exchange(ctx context.Context, server string, q dnsmessage.Que
 	q.Class = dnsmessage.ClassINET
 	id, udpReq, tcpReq, err := newRequest(q)
 	if err != nil {
-		return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("cannot marshal DNS message")
+		return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotMarshalDNSMessage
 	}
 	for _, network := range []string{"udp", "tcp"} {
 		ctx, cancel := context.WithDeadline(ctx, time.Now().Add(timeout))
@@ -147,31 +161,31 @@ func (r *Resolver) exchange(ctx context.Context, server string, q dnsmessage.Que
 			return dnsmessage.Parser{}, dnsmessage.Header{}, mapErr(err)
 		}
 		if err := p.SkipQuestion(); err != dnsmessage.ErrSectionDone {
-			return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("invalid DNS response")
+			return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
 		}
 		if h.Truncated { // see RFC 5966
 			continue
 		}
 		return p, h, nil
 	}
-	return dnsmessage.Parser{}, dnsmessage.Header{}, errors.New("no answer from DNS server")
+	return dnsmessage.Parser{}, dnsmessage.Header{}, errNoAnswerFromDNSServer
 }
 
 // checkHeader performs basic sanity checks on the header.
 func checkHeader(p *dnsmessage.Parser, h dnsmessage.Header, name, server string) error {
+	if h.RCode == dnsmessage.RCodeNameError {
+		return errNoSuchHost
+	}
+
 	_, err := p.AnswerHeader()
 	if err != nil && err != dnsmessage.ErrSectionDone {
-		return &DNSError{
-			Err:    "cannot unmarshal DNS message",
-			Name:   name,
-			Server: server,
-		}
+		return errCannotUnmarshalDNSMessage
 	}
 
 	// libresolv continues to the next server when it receives
 	// an invalid referral response. See golang.org/issue/15434.
 	if h.RCode == dnsmessage.RCodeSuccess && !h.Authoritative && !h.RecursionAvailable && err == dnsmessage.ErrSectionDone {
-		return &DNSError{Err: "lame referral", Name: name, Server: server}
+		return errLameReferral
 	}
 
 	if h.RCode != dnsmessage.RCodeSuccess && h.RCode != dnsmessage.RCodeNameError {
@@ -180,11 +194,10 @@ func checkHeader(p *dnsmessage.Parser, h dnsmessage.Header, name, server string)
 		// a name error and we didn't get success,
 		// the server is behaving incorrectly or
 		// having temporary trouble.
-		err := &DNSError{Err: "server misbehaving", Name: name, Server: server}
 		if h.RCode == dnsmessage.RCodeServerFailure {
-			err.IsTemporary = true
+			return errServerTemporarlyMisbehaving
 		}
-		return err
+		return errServerMisbehaving
 	}
 
 	return nil
@@ -194,28 +207,16 @@ func skipToAnswer(p *dnsmessage.Parser, qtype dnsmessage.Type, name, server stri
 	for {
 		h, err := p.AnswerHeader()
 		if err == dnsmessage.ErrSectionDone {
-			return &DNSError{
-				Err:    errNoSuchHost.Error(),
-				Name:   name,
-				Server: server,
-			}
+			return errNoSuchHost
 		}
 		if err != nil {
-			return &DNSError{
-				Err:    "cannot unmarshal DNS message",
-				Name:   name,
-				Server: server,
-			}
+			return errCannotUnmarshalDNSMessage
 		}
 		if h.Type == qtype {
 			return nil
 		}
 		if err := p.SkipAnswer(); err != nil {
-			return &DNSError{
-				Err:    "cannot unmarshal DNS message",
-				Name:   name,
-				Server: server,
-			}
+			return errCannotUnmarshalDNSMessage
 		}
 	}
 }
@@ -229,7 +230,7 @@ func (r *Resolver) tryOneName(ctx context.Context, cfg *dnsConfig, name string,
 
 	n, err := dnsmessage.NewName(name)
 	if err != nil {
-		return dnsmessage.Parser{}, "", errors.New("cannot marshal DNS message")
+		return dnsmessage.Parser{}, "", errCannotMarshalDNSMessage
 	}
 	q := dnsmessage.Question{
 		Name:  n,
@@ -243,38 +244,62 @@ func (r *Resolver) tryOneName(ctx context.Context, cfg *dnsConfig, name string,
 
 			p, h, err := r.exchange(ctx, server, q, cfg.timeout)
 			if err != nil {
-				lastErr = &DNSError{
+				dnsErr := &DNSError{
 					Err:    err.Error(),
 					Name:   name,
 					Server: server,
 				}
 				if nerr, ok := err.(Error); ok && nerr.Timeout() {
-					lastErr.(*DNSError).IsTimeout = true
+					dnsErr.IsTimeout = true
 				}
 				// Set IsTemporary for socket-level errors. Note that this flag
 				// may also be used to indicate a SERVFAIL response.
 				if _, ok := err.(*OpError); ok {
-					lastErr.(*DNSError).IsTemporary = true
+					dnsErr.IsTemporary = true
 				}
+				lastErr = dnsErr
 				continue
 			}
 
-			// The name does not exist, so trying another server won't help.
-			//
-			// TODO: indicate this in a more obvious way, such as a field on DNSError?
-			if h.RCode == dnsmessage.RCodeNameError {
-				return dnsmessage.Parser{}, "", &DNSError{Err: errNoSuchHost.Error(), Name: name, Server: server}
-			}
-
-			lastErr = checkHeader(&p, h, name, server)
-			if lastErr != nil {
+			if err := checkHeader(&p, h, name, server); err != nil {
+				dnsErr := &DNSError{
+					Err:    err.Error(),
+					Name:   name,
+					Server: server,
+				}
+				if err == errServerTemporarlyMisbehaving {
+					dnsErr.IsTemporary = true
+				}
+				if err == errNoSuchHost {
+					// The name does not exist, so trying
+					// another server won't help.
+					//
+					// TODO: indicate this in a more
+					// obvious way, such as a field on
+					// DNSError?
+					return p, server, dnsErr
+				}
+				lastErr = dnsErr
 				continue
 			}
 
-			lastErr = skipToAnswer(&p, qtype, name, server)
-			if lastErr == nil {
+			err = skipToAnswer(&p, qtype, name, server)
+			if err == nil {
 				return p, server, nil
 			}
+			lastErr = &DNSError{
+				Err:    err.Error(),
+				Name:   name,
+				Server: server,
+			}
+			if err == errNoSuchHost {
+				// The name does not exist, so trying another
+				// server won't help.
+				//
+				// TODO: indicate this in a more obvious way,
+				// such as a field on DNSError?
+				return p, server, lastErr
+			}
 		}
 	}
 	return dnsmessage.Parser{}, "", lastErr
diff --git a/libgo/go/net/dnsclient_unix_test.go b/libgo/go/net/dnsclient_unix_test.go
index f1bb09d..8992480 100644
--- a/libgo/go/net/dnsclient_unix_test.go
+++ b/libgo/go/net/dnsclient_unix_test.go
@@ -1427,28 +1427,35 @@ func TestDNSGoroutineRace(t *testing.T) {
 	}
 }
 
+func lookupWithFake(fake fakeDNSServer, name string, typ dnsmessage.Type) error {
+	r := Resolver{PreferGo: true, Dial: fake.DialContext}
+
+	resolvConf.mu.RLock()
+	conf := resolvConf.dnsConfig
+	resolvConf.mu.RUnlock()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	_, _, err := r.tryOneName(ctx, conf, name, typ)
+	return err
+}
+
 // Issue 8434: verify that Temporary returns true on an error when rcode
 // is SERVFAIL
 func TestIssue8434(t *testing.T) {
-	msg := dnsmessage.Message{
-		Header: dnsmessage.Header{
-			RCode: dnsmessage.RCodeServerFailure,
+	err := lookupWithFake(fakeDNSServer{
+		rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+			return dnsmessage.Message{
+				Header: dnsmessage.Header{
+					ID:       q.ID,
+					Response: true,
+					RCode:    dnsmessage.RCodeServerFailure,
+				},
+				Questions: q.Questions,
+			}, nil
 		},
-	}
-	b, err := msg.Pack()
-	if err != nil {
-		t.Fatal("Pack failed:", err)
-	}
-	var p dnsmessage.Parser
-	h, err := p.Start(b)
-	if err != nil {
-		t.Fatal("Start failed:", err)
-	}
-	if err := p.SkipAllQuestions(); err != nil {
-		t.Fatal("SkipAllQuestions failed:", err)
-	}
-
-	err = checkHeader(&p, h, "golang.org", "foo:53")
+	}, "golang.org.", dnsmessage.TypeALL)
 	if err == nil {
 		t.Fatal("expected an error")
 	}
@@ -1464,50 +1471,76 @@ func TestIssue8434(t *testing.T) {
 	}
 }
 
-// Issue 12778: verify that NXDOMAIN without RA bit errors as
-// "no such host" and not "server misbehaving"
+// TestNoSuchHost verifies that tryOneName works correctly when the domain does
+// not exist.
+//
+// Issue 12778: verify that NXDOMAIN without RA bit errors as "no such host"
+// and not "server misbehaving"
 //
 // Issue 25336: verify that NXDOMAIN errors fail fast.
-func TestIssue12778(t *testing.T) {
-	lookups := 0
-	fake := fakeDNSServer{
-		rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
-			lookups++
-			return dnsmessage.Message{
-				Header: dnsmessage.Header{
-					ID:                 q.ID,
-					Response:           true,
-					RCode:              dnsmessage.RCodeNameError,
-					RecursionAvailable: false,
-				},
-				Questions: q.Questions,
-			}, nil
+//
+// Issue 27525: verify that empty answers fail fast.
+func TestNoSuchHost(t *testing.T) {
+	tests := []struct {
+		name string
+		f    func(string, string, dnsmessage.Message, time.Time) (dnsmessage.Message, error)
+	}{
+		{
+			"NXDOMAIN",
+			func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+				return dnsmessage.Message{
+					Header: dnsmessage.Header{
+						ID:                 q.ID,
+						Response:           true,
+						RCode:              dnsmessage.RCodeNameError,
+						RecursionAvailable: false,
+					},
+					Questions: q.Questions,
+				}, nil
+			},
+		},
+		{
+			"no answers",
+			func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+				return dnsmessage.Message{
+					Header: dnsmessage.Header{
+						ID:                 q.ID,
+						Response:           true,
+						RCode:              dnsmessage.RCodeSuccess,
+						RecursionAvailable: false,
+						Authoritative:      true,
+					},
+					Questions: q.Questions,
+				}, nil
+			},
 		},
 	}
-	r := Resolver{PreferGo: true, Dial: fake.DialContext}
-
-	resolvConf.mu.RLock()
-	conf := resolvConf.dnsConfig
-	resolvConf.mu.RUnlock()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
 
-	_, _, err := r.tryOneName(ctx, conf, ".", dnsmessage.TypeALL)
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			lookups := 0
+			err := lookupWithFake(fakeDNSServer{
+				rh: func(n, s string, q dnsmessage.Message, d time.Time) (dnsmessage.Message, error) {
+					lookups++
+					return test.f(n, s, q, d)
+				},
+			}, ".", dnsmessage.TypeALL)
 
-	if lookups != 1 {
-		t.Errorf("got %d lookups, wanted 1", lookups)
-	}
+			if lookups != 1 {
+				t.Errorf("got %d lookups, wanted 1", lookups)
+			}
 
-	if err == nil {
-		t.Fatal("expected an error")
-	}
-	de, ok := err.(*DNSError)
-	if !ok {
-		t.Fatalf("err = %#v; wanted a *net.DNSError", err)
-	}
-	if de.Err != errNoSuchHost.Error() {
-		t.Fatalf("Err = %#v; wanted %q", de.Err, errNoSuchHost.Error())
+			if err == nil {
+				t.Fatal("expected an error")
+			}
+			de, ok := err.(*DNSError)
+			if !ok {
+				t.Fatalf("err = %#v; wanted a *net.DNSError", err)
+			}
+			if de.Err != errNoSuchHost.Error() {
+				t.Fatalf("Err = %#v; wanted %q", de.Err, errNoSuchHost.Error())
+			}
+		})
 	}
 }
 
@@ -1535,3 +1568,56 @@ func TestDNSDialTCP(t *testing.T) {
 		t.Fatal("exhange failed:", err)
 	}
 }
+
+// Issue 27763: verify that two strings in one TXT record are concatenated.
+func TestTXTRecordTwoStrings(t *testing.T) {
+	fake := fakeDNSServer{
+		rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+			r := dnsmessage.Message{
+				Header: dnsmessage.Header{
+					ID:       q.Header.ID,
+					Response: true,
+					RCode:    dnsmessage.RCodeSuccess,
+				},
+				Questions: q.Questions,
+				Answers: []dnsmessage.Resource{
+					{
+						Header: dnsmessage.ResourceHeader{
+							Name:  q.Questions[0].Name,
+							Type:  dnsmessage.TypeA,
+							Class: dnsmessage.ClassINET,
+						},
+						Body: &dnsmessage.TXTResource{
+							TXT: []string{"string1 ", "string2"},
+						},
+					},
+					{
+						Header: dnsmessage.ResourceHeader{
+							Name:  q.Questions[0].Name,
+							Type:  dnsmessage.TypeA,
+							Class: dnsmessage.ClassINET,
+						},
+						Body: &dnsmessage.TXTResource{
+							TXT: []string{"onestring"},
+						},
+					},
+				},
+			}
+			return r, nil
+		},
+	}
+	r := Resolver{PreferGo: true, Dial: fake.DialContext}
+	txt, err := r.lookupTXT(context.Background(), "golang.org")
+	if err != nil {
+		t.Fatal("LookupTXT failed:", err)
+	}
+	if want := 2; len(txt) != want {
+		t.Fatalf("len(txt), got %d, want %d", len(txt), want)
+	}
+	if want := "string1 string2"; txt[0] != want {
+		t.Errorf("txt[0], got %q, want %q", txt[0], want)
+	}
+	if want := "onestring"; txt[1] != want {
+		t.Errorf("txt[1], got %q, want %q", txt[1], want)
+	}
+}
diff --git a/libgo/go/net/http/roundtrip_js.go b/libgo/go/net/http/roundtrip_js.go
index 16b7b89..38e4f55 100644
--- a/libgo/go/net/http/roundtrip_js.go
+++ b/libgo/go/net/http/roundtrip_js.go
@@ -116,7 +116,9 @@ func (t *Transport) RoundTrip(req *Request) (*Response, error) {
 
 		b := result.Get("body")
 		var body io.ReadCloser
-		if b != js.Undefined() {
+		// The body is undefined when the browser does not support streaming response bodies (Firefox),
+		// and null in certain error cases, i.e. when the request is blocked because of CORS settings.
+		if b != js.Undefined() && b != js.Null() {
 			body = &streamReader{stream: b.Call("getReader")}
 		} else {
 			// Fall back to using ArrayBuffer
diff --git a/libgo/go/net/lookup_unix.go b/libgo/go/net/lookup_unix.go
index 76d6ae3..39e8b72 100644
--- a/libgo/go/net/lookup_unix.go
+++ b/libgo/go/net/lookup_unix.go
@@ -299,11 +299,21 @@ func (r *Resolver) lookupTXT(ctx context.Context, name string) ([]string, error)
 				Server: server,
 			}
 		}
+		// Multiple strings in one TXT record need to be
+		// concatenated without separator to be consistent
+		// with previous Go resolver.
+		n := 0
+		for _, s := range txt.TXT {
+			n += len(s)
+		}
+		txtJoin := make([]byte, 0, n)
+		for _, s := range txt.TXT {
+			txtJoin = append(txtJoin, s...)
+		}
 		if len(txts) == 0 {
-			txts = txt.TXT
-		} else {
-			txts = append(txts, txt.TXT...)
+			txts = make([]string, 0, 1)
 		}
+		txts = append(txts, string(txtJoin))
 	}
 	return txts, nil
 }
diff --git a/libgo/go/net/splice_test.go b/libgo/go/net/splice_test.go
index 40ed19b..3be1c7e 100644
--- a/libgo/go/net/splice_test.go
+++ b/libgo/go/net/splice_test.go
@@ -124,6 +124,7 @@ func testSpliceBig(t *testing.T) {
 func testSpliceHonorsLimitedReader(t *testing.T) {
 	t.Run("stopsAfterN", testSpliceStopsAfterN)
 	t.Run("updatesN", testSpliceUpdatesN)
+	t.Run("readerAtLimit", testSpliceReaderAtLimit)
 }
 
 func testSpliceStopsAfterN(t *testing.T) {
@@ -210,7 +211,7 @@ func testSpliceUpdatesN(t *testing.T) {
 	}
 }
 
-func testSpliceReaderAtEOF(t *testing.T) {
+func testSpliceReaderAtLimit(t *testing.T) {
 	clientUp, serverUp, err := spliceTestSocketPair("tcp")
 	if err != nil {
 		t.Fatal(err)
@@ -224,22 +225,64 @@ func testSpliceReaderAtEOF(t *testing.T) {
 	defer clientDown.Close()
 	defer serverDown.Close()
 
-	serverUp.Close()
-	_, err, handled := splice(serverDown.(*TCPConn).fd, serverUp)
+	lr := &io.LimitedReader{
+		N: 0,
+		R: serverUp,
+	}
+	_, err, handled := splice(serverDown.(*TCPConn).fd, lr)
 	if !handled {
 		if serr, ok := err.(*os.SyscallError); ok && serr.Syscall == "pipe2" && serr.Err == syscall.ENOSYS {
 			t.Skip("pipe2 not supported")
 		}
 
-		t.Errorf("closed connection: got err = %v, handled = %t, want handled = true", err, handled)
+		t.Errorf("exhausted LimitedReader: got err = %v, handled = %t, want handled = true", err, handled)
 	}
-	lr := &io.LimitedReader{
-		N: 0,
-		R: serverUp,
+}
+
+func testSpliceReaderAtEOF(t *testing.T) {
+	clientUp, serverUp, err := spliceTestSocketPair("tcp")
+	if err != nil {
+		t.Fatal(err)
 	}
-	_, err, handled = splice(serverDown.(*TCPConn).fd, lr)
-	if !handled {
-		t.Errorf("exhausted LimitedReader: got err = %v, handled = %t, want handled = true", err, handled)
+	defer clientUp.Close()
+	clientDown, serverDown, err := spliceTestSocketPair("tcp")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer clientDown.Close()
+
+	serverUp.Close()
+
+	// We'd like to call net.splice here and check the handled return
+	// value, but we disable splice on old Linux kernels.
+	//
+	// In that case, poll.Splice and net.splice return a non-nil error
+	// and handled == false. We'd ideally like to see handled == true
+	// because the source reader is at EOF, but if we're running on an old
+	// kernel, and splice is disabled, we won't see EOF from net.splice,
+	// because we won't touch the reader at all.
+	//
+	// Trying to untangle the errors from net.splice and match them
+	// against the errors created by the poll package would be brittle,
+	// so this is a higher level test.
+	//
+	// The following ReadFrom should return immediately, regardless of
+	// whether splice is disabled or not. The other side should then
+	// get a goodbye signal. Test for the goodbye signal.
+	msg := "bye"
+	go func() {
+		serverDown.(*TCPConn).ReadFrom(serverUp)
+		io.WriteString(serverDown, msg)
+		serverDown.Close()
+	}()
+
+	buf := make([]byte, 3)
+	_, err = io.ReadFull(clientDown, buf)
+	if err != nil {
+		t.Errorf("clientDown: %v", err)
+	}
+	if string(buf) != msg {
+		t.Errorf("clientDown got %q, want %q", buf, msg)
 	}
 }