libgo: Merge from revision 18783:00cce3a34d7e of master library.

This revision was committed January 7, 2014.  The next
revision deleted runtime/mfinal.c.  That will be done in a
subsequent merge.

This merge changes type descriptors to add a zero field,
pointing to a zero value for that type.  This is implemented
as a common variable.

	* go-gcc.cc (Gcc_backend::implicit_variable): Add is_common and
	alignment parameters.  Permit init parameter to be NULL.

From-SVN: r211249

14 files changed, 266 insertions, 97 deletions

diff --git a/libgo/go/net/http/client_test.go b/libgo/go/net/http/client_test.go
index 997d04151c2..e5ad39c7741 100644
--- a/libgo/go/net/http/client_test.go
+++ b/libgo/go/net/http/client_test.go
@@ -373,24 +373,6 @@ func (j *TestJar) Cookies(u *url.URL) []*Cookie {
 	return j.perURL[u.Host]
 }
 
-func TestRedirectCookiesOnRequest(t *testing.T) {
-	defer afterTest(t)
-	var ts *httptest.Server
-	ts = httptest.NewServer(echoCookiesRedirectHandler)
-	defer ts.Close()
-	c := &Client{}
-	req, _ := NewRequest("GET", ts.URL, nil)
-	req.AddCookie(expectedCookies[0])
-	// TODO: Uncomment when an implementation of a RFC6265 cookie jar lands.
-	_ = c
-	// resp, _ := c.Do(req)
-	// matchReturnedCookies(t, expectedCookies, resp.Cookies())
-
-	req, _ = NewRequest("GET", ts.URL, nil)
-	// resp, _ = c.Do(req)
-	// matchReturnedCookies(t, expectedCookies[1:], resp.Cookies())
-}
-
 func TestRedirectCookiesJar(t *testing.T) {
 	defer afterTest(t)
 	var ts *httptest.Server
@@ -410,8 +392,8 @@ func TestRedirectCookiesJar(t *testing.T) {
 }
 
 func matchReturnedCookies(t *testing.T, expected, given []*Cookie) {
-	t.Logf("Received cookies: %v", given)
 	if len(given) != len(expected) {
+		t.Logf("Received cookies: %v", given)
 		t.Errorf("Expected %d cookies, got %d", len(expected), len(given))
 	}
 	for _, ec := range expected {
diff --git a/libgo/go/net/http/cookie.go b/libgo/go/net/http/cookie.go
index 8b01c508eb1..a1759214f38 100644
--- a/libgo/go/net/http/cookie.go
+++ b/libgo/go/net/http/cookie.go
@@ -94,7 +94,6 @@ func readSetCookies(h Header) []*Cookie {
 				continue
 			case "domain":
 				c.Domain = val
-				// TODO: Add domain parsing
 				continue
 			case "max-age":
 				secs, err := strconv.Atoi(val)
@@ -121,7 +120,6 @@ func readSetCookies(h Header) []*Cookie {
 				continue
 			case "path":
 				c.Path = val
-				// TODO: Add path parsing
 				continue
 			}
 			c.Unparsed = append(c.Unparsed, parts[i])
diff --git a/libgo/go/net/http/cookie_test.go b/libgo/go/net/http/cookie_test.go
index 11b01cc5713..1aa9d49d96e 100644
--- a/libgo/go/net/http/cookie_test.go
+++ b/libgo/go/net/http/cookie_test.go
@@ -5,9 +5,13 @@
 package http
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
+	"log"
+	"os"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 )
@@ -51,12 +55,20 @@ var writeSetCookiesTests = []struct {
 }
 
 func TestWriteSetCookies(t *testing.T) {
+	defer log.SetOutput(os.Stderr)
+	var logbuf bytes.Buffer
+	log.SetOutput(&logbuf)
+
 	for i, tt := range writeSetCookiesTests {
 		if g, e := tt.Cookie.String(), tt.Raw; g != e {
 			t.Errorf("Test %d, expecting:\n%s\nGot:\n%s\n", i, e, g)
 			continue
 		}
 	}
+
+	if got, sub := logbuf.String(), "dropping domain attribute"; !strings.Contains(got, sub) {
+		t.Errorf("Expected substring %q in log output. Got:\n%s", sub, got)
+	}
 }
 
 type headerOnlyResponseWriter Header
@@ -244,6 +256,10 @@ func TestReadCookies(t *testing.T) {
 }
 
 func TestCookieSanitizeValue(t *testing.T) {
+	defer log.SetOutput(os.Stderr)
+	var logbuf bytes.Buffer
+	log.SetOutput(&logbuf)
+
 	tests := []struct {
 		in, want string
 	}{
@@ -257,9 +273,17 @@ func TestCookieSanitizeValue(t *testing.T) {
 			t.Errorf("sanitizeCookieValue(%q) = %q; want %q", tt.in, got, tt.want)
 		}
 	}
+
+	if got, sub := logbuf.String(), "dropping invalid bytes"; !strings.Contains(got, sub) {
+		t.Errorf("Expected substring %q in log output. Got:\n%s", sub, got)
+	}
 }
 
 func TestCookieSanitizePath(t *testing.T) {
+	defer log.SetOutput(os.Stderr)
+	var logbuf bytes.Buffer
+	log.SetOutput(&logbuf)
+
 	tests := []struct {
 		in, want string
 	}{
@@ -272,4 +296,8 @@ func TestCookieSanitizePath(t *testing.T) {
 			t.Errorf("sanitizeCookiePath(%q) = %q; want %q", tt.in, got, tt.want)
 		}
 	}
+
+	if got, sub := logbuf.String(), "dropping invalid bytes"; !strings.Contains(got, sub) {
+		t.Errorf("Expected substring %q in log output. Got:\n%s", sub, got)
+	}
 }
diff --git a/libgo/go/net/http/cookiejar/jar.go b/libgo/go/net/http/cookiejar/jar.go
index 389ab58e418..82f18a17848 100644
--- a/libgo/go/net/http/cookiejar/jar.go
+++ b/libgo/go/net/http/cookiejar/jar.go
@@ -34,9 +34,9 @@ import (
 type PublicSuffixList interface {
 	// PublicSuffix returns the public suffix of domain.
 	//
-	// TODO: specify which of the caller and callee is responsible for IP
-	// addresses, for leading and trailing dots, for case sensitivity, and
-	// for IDN/Punycode.
+	// Domain is a lowercase punycoded domain name (not an IP address)
+	// without leading or trailing dots. The returned value is in the
+	// same form.
 	PublicSuffix(domain string) string
 
 	// String returns a description of the source of this public suffix
diff --git a/libgo/go/net/http/header.go b/libgo/go/net/http/header.go
index ca1ae07c25d..de62bef5525 100644
--- a/libgo/go/net/http/header.go
+++ b/libgo/go/net/http/header.go
@@ -9,6 +9,7 @@ import (
 	"net/textproto"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -114,18 +115,15 @@ func (s *headerSorter) Len() int           { return len(s.kvs) }
 func (s *headerSorter) Swap(i, j int)      { s.kvs[i], s.kvs[j] = s.kvs[j], s.kvs[i] }
 func (s *headerSorter) Less(i, j int) bool { return s.kvs[i].key < s.kvs[j].key }
 
-// TODO: convert this to a sync.Cache (issue 4720)
-var headerSorterCache = make(chan *headerSorter, 8)
+var headerSorterPool = sync.Pool{
+	New: func() interface{} { return new(headerSorter) },
+}
 
 // sortedKeyValues returns h's keys sorted in the returned kvs
 // slice. The headerSorter used to sort is also returned, for possible
 // return to headerSorterCache.
 func (h Header) sortedKeyValues(exclude map[string]bool) (kvs []keyValues, hs *headerSorter) {
-	select {
-	case hs = <-headerSorterCache:
-	default:
-		hs = new(headerSorter)
-	}
+	hs = headerSorterPool.Get().(*headerSorter)
 	if cap(hs.kvs) < len(h) {
 		hs.kvs = make([]keyValues, 0, len(h))
 	}
@@ -159,10 +157,7 @@ func (h Header) WriteSubset(w io.Writer, exclude map[string]bool) error {
 			}
 		}
 	}
-	select {
-	case headerSorterCache <- sorter:
-	default:
-	}
+	headerSorterPool.Put(sorter)
 	return nil
 }
 
diff --git a/libgo/go/net/http/request.go b/libgo/go/net/http/request.go
index 57b5d094847..7a97770314d 100644
--- a/libgo/go/net/http/request.go
+++ b/libgo/go/net/http/request.go
@@ -20,6 +20,7 @@ import (
 	"net/url"
 	"strconv"
 	"strings"
+	"sync"
 )
 
 const (
@@ -494,25 +495,20 @@ func parseRequestLine(line string) (method, requestURI, proto string, ok bool) {
 	return line[:s1], line[s1+1 : s2], line[s2+1:], true
 }
 
-// TODO(bradfitz): use a sync.Cache when available
-var textprotoReaderCache = make(chan *textproto.Reader, 4)
+var textprotoReaderPool sync.Pool
 
 func newTextprotoReader(br *bufio.Reader) *textproto.Reader {
-	select {
-	case r := <-textprotoReaderCache:
-		r.R = br
-		return r
-	default:
-		return textproto.NewReader(br)
+	if v := textprotoReaderPool.Get(); v != nil {
+		tr := v.(*textproto.Reader)
+		tr.R = br
+		return tr
 	}
+	return textproto.NewReader(br)
 }
 
 func putTextprotoReader(r *textproto.Reader) {
 	r.R = nil
-	select {
-	case textprotoReaderCache <- r:
-	default:
-	}
+	textprotoReaderPool.Put(r)
 }
 
 // ReadRequest reads and parses a request from b.
@@ -677,6 +673,11 @@ func parsePostForm(r *Request) (vs url.Values, err error) {
 		return
 	}
 	ct := r.Header.Get("Content-Type")
+	// RFC 2616, section 7.2.1 - empty type
+	//   SHOULD be treated as application/octet-stream
+	if ct == "" {
+		ct = "application/octet-stream"
+	}
 	ct, _, err = mime.ParseMediaType(ct)
 	switch {
 	case ct == "application/x-www-form-urlencoded":
@@ -707,7 +708,7 @@ func parsePostForm(r *Request) (vs url.Values, err error) {
 		// orders to call too many functions here.
 		// Clean this up and write more tests.
 		// request_test.go contains the start of this,
-		// in TestRequestMultipartCallOrder.
+		// in TestParseMultipartFormOrder and others.
 	}
 	return
 }
diff --git a/libgo/go/net/http/request_test.go b/libgo/go/net/http/request_test.go
index 89303c33602..0c1e16b8d5e 100644
--- a/libgo/go/net/http/request_test.go
+++ b/libgo/go/net/http/request_test.go
@@ -68,8 +68,9 @@ type parseContentTypeTest struct {
 
 var parseContentTypeTests = []parseContentTypeTest{
 	{false, stringMap{"Content-Type": {"text/plain"}}},
-	// Non-existent keys are not placed. The value nil is illegal.
-	{true, stringMap{}},
+	// Empty content type is legal - shoult be treated as
+	// application/octet-stream (RFC 2616, section 7.2.1)
+	{false, stringMap{}},
 	{true, stringMap{"Content-Type": {"text/plain; boundary="}}},
 	{false, stringMap{"Content-Type": {"application/unknown"}}},
 }
@@ -198,15 +199,39 @@ func TestEmptyMultipartRequest(t *testing.T) {
 	testMissingFile(t, req)
 }
 
-func TestRequestMultipartCallOrder(t *testing.T) {
+// Test that ParseMultipartForm errors if called
+// after MultipartReader on the same request.
+func TestParseMultipartFormOrder(t *testing.T) {
 	req := newTestMultipartRequest(t)
-	_, err := req.MultipartReader()
-	if err != nil {
+	if _, err := req.MultipartReader(); err != nil {
+		t.Fatalf("MultipartReader: %v", err)
+	}
+	if err := req.ParseMultipartForm(1024); err == nil {
+		t.Fatal("expected an error from ParseMultipartForm after call to MultipartReader")
+	}
+}
+
+// Test that MultipartReader errors if called
+// after ParseMultipartForm on the same request.
+func TestMultipartReaderOrder(t *testing.T) {
+	req := newTestMultipartRequest(t)
+	if err := req.ParseMultipartForm(25); err != nil {
+		t.Fatalf("ParseMultipartForm: %v", err)
+	}
+	if _, err := req.MultipartReader(); err == nil {
+		t.Fatal("expected an error from MultipartReader after call to ParseMultipartForm")
+	}
+}
+
+// Test that FormFile errors if called after
+// MultipartReader on the same request.
+func TestFormFileOrder(t *testing.T) {
+	req := newTestMultipartRequest(t)
+	if _, err := req.MultipartReader(); err != nil {
 		t.Fatalf("MultipartReader: %v", err)
 	}
-	err = req.ParseMultipartForm(1024)
-	if err == nil {
-		t.Errorf("expected an error from ParseMultipartForm after call to MultipartReader")
+	if _, _, err := req.FormFile(""); err == nil {
+		t.Fatal("expected an error from FormFile after call to MultipartReader")
 	}
 }
 
diff --git a/libgo/go/net/http/response.go b/libgo/go/net/http/response.go
index 35d0ba3bb15..2ec1d408728 100644
--- a/libgo/go/net/http/response.go
+++ b/libgo/go/net/http/response.go
@@ -187,6 +187,7 @@ func (r *Response) ProtoAtLeast(major, minor int) bool {
 //  ContentLength
 //  Header, values for non-canonical keys will have unpredictable behavior
 //
+// Body is closed after it is sent.
 func (r *Response) Write(w io.Writer) error {
 
 	// Status line
diff --git a/libgo/go/net/http/response_test.go b/libgo/go/net/http/response_test.go
index 5044306a876..f73172189e9 100644
--- a/libgo/go/net/http/response_test.go
+++ b/libgo/go/net/http/response_test.go
@@ -14,6 +14,7 @@ import (
 	"io/ioutil"
 	"net/url"
 	"reflect"
+	"regexp"
 	"strings"
 	"testing"
 )
@@ -406,8 +407,7 @@ func TestWriteResponse(t *testing.T) {
 			t.Errorf("#%d: %v", i, err)
 			continue
 		}
-		bout := bytes.NewBuffer(nil)
-		err = resp.Write(bout)
+		err = resp.Write(ioutil.Discard)
 		if err != nil {
 			t.Errorf("#%d: %v", i, err)
 			continue
@@ -506,6 +506,9 @@ func TestReadResponseCloseInMiddle(t *testing.T) {
 		rest, err := ioutil.ReadAll(bufr)
 		checkErr(err, "ReadAll on remainder")
 		if e, g := "Next Request Here", string(rest); e != g {
+			g = regexp.MustCompile(`(xx+)`).ReplaceAllStringFunc(g, func(match string) string {
+				return fmt.Sprintf("x(repeated x%d)", len(match))
+			})
 			fatalf("remainder = %q, expected %q", g, e)
 		}
 	}
diff --git a/libgo/go/net/http/serve_test.go b/libgo/go/net/http/serve_test.go
index 8961cf491f8..1dba1873ea5 100644
--- a/libgo/go/net/http/serve_test.go
+++ b/libgo/go/net/http/serve_test.go
@@ -1934,6 +1934,31 @@ func TestWriteAfterHijack(t *testing.T) {
 	}
 }
 
+func TestDoubleHijack(t *testing.T) {
+	req := reqBytes("GET / HTTP/1.1\nHost: golang.org")
+	var buf bytes.Buffer
+	conn := &rwTestConn{
+		Reader: bytes.NewReader(req),
+		Writer: &buf,
+		closec: make(chan bool, 1),
+	}
+	handler := HandlerFunc(func(rw ResponseWriter, r *Request) {
+		conn, _, err := rw.(Hijacker).Hijack()
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		_, _, err = rw.(Hijacker).Hijack()
+		if err == nil {
+			t.Errorf("got err = nil;  want err != nil")
+		}
+		conn.Close()
+	})
+	ln := &oneConnListener{conn: conn}
+	go Serve(ln, handler)
+	<-conn.closec
+}
+
 // http://code.google.com/p/go/issues/detail?id=5955
 // Note that this does not test the "request too large"
 // exit path from the http server. This is intentional;
@@ -2065,6 +2090,64 @@ func TestNoContentTypeOnNotModified(t *testing.T) {
 	}
 }
 
+// Issue 6995
+// A server Handler can receive a Request, and then turn around and
+// give a copy of that Request.Body out to the Transport (e.g. any
+// proxy).  So then two people own that Request.Body (both the server
+// and the http client), and both think they can close it on failure.
+// Therefore, all incoming server requests Bodies need to be thread-safe.
+func TestTransportAndServerSharedBodyRace(t *testing.T) {
+	defer afterTest(t)
+
+	const bodySize = 1 << 20
+
+	unblockBackend := make(chan bool)
+	backend := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
+		io.CopyN(rw, req.Body, bodySize/2)
+		<-unblockBackend
+	}))
+	defer backend.Close()
+
+	backendRespc := make(chan *Response, 1)
+	proxy := httptest.NewServer(HandlerFunc(func(rw ResponseWriter, req *Request) {
+		if req.RequestURI == "/foo" {
+			rw.Write([]byte("bar"))
+			return
+		}
+		req2, _ := NewRequest("POST", backend.URL, req.Body)
+		req2.ContentLength = bodySize
+
+		bresp, err := DefaultClient.Do(req2)
+		if err != nil {
+			t.Errorf("Proxy outbound request: %v", err)
+			return
+		}
+		_, err = io.CopyN(ioutil.Discard, bresp.Body, bodySize/4)
+		if err != nil {
+			t.Errorf("Proxy copy error: %v", err)
+			return
+		}
+		backendRespc <- bresp // to close later
+
+		// Try to cause a race: Both the DefaultTransport and the proxy handler's Server
+		// will try to read/close req.Body (aka req2.Body)
+		DefaultTransport.(*Transport).CancelRequest(req2)
+		rw.Write([]byte("OK"))
+	}))
+	defer proxy.Close()
+
+	req, _ := NewRequest("POST", proxy.URL, io.LimitReader(neverEnding('a'), bodySize))
+	res, err := DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("Original request: %v", err)
+	}
+
+	// Cleanup, so we don't leak goroutines.
+	res.Body.Close()
+	close(unblockBackend)
+	(<-backendRespc).Body.Close()
+}
+
 func TestResponseWriterWriteStringAllocs(t *testing.T) {
 	t.Skip("allocs test unreliable with gccgo")
 	ht := newHandlerTest(HandlerFunc(func(w ResponseWriter, r *Request) {
@@ -2391,3 +2474,28 @@ Host: golang.org
 		b.Errorf("b.N=%d but handled %d", b.N, handled)
 	}
 }
+
+func BenchmarkServerHijack(b *testing.B) {
+	b.ReportAllocs()
+	req := reqBytes(`GET / HTTP/1.1
+Host: golang.org
+`)
+	h := HandlerFunc(func(w ResponseWriter, r *Request) {
+		conn, _, err := w.(Hijacker).Hijack()
+		if err != nil {
+			panic(err)
+		}
+		conn.Close()
+	})
+	conn := &rwTestConn{
+		Writer: ioutil.Discard,
+		closec: make(chan bool, 1),
+	}
+	ln := &oneConnListener{conn: conn}
+	for i := 0; i < b.N; i++ {
+		conn.Reader = bytes.NewReader(req)
+		ln.conn = conn
+		Serve(ln, h)
+		<-conn.closec
+	}
+}
diff --git a/libgo/go/net/http/server.go b/libgo/go/net/http/server.go
index 0e46863d5ae..7ebd8575f3b 100644
--- a/libgo/go/net/http/server.go
+++ b/libgo/go/net/http/server.go
@@ -435,56 +435,52 @@ func (srv *Server) newConn(rwc net.Conn) (c *conn, err error) {
 	return c, nil
 }
 
-// TODO: use a sync.Cache instead
 var (
-	bufioReaderCache   = make(chan *bufio.Reader, 4)
-	bufioWriterCache2k = make(chan *bufio.Writer, 4)
-	bufioWriterCache4k = make(chan *bufio.Writer, 4)
+	bufioReaderPool   sync.Pool
+	bufioWriter2kPool sync.Pool
+	bufioWriter4kPool sync.Pool
 )
 
-func bufioWriterCache(size int) chan *bufio.Writer {
+func bufioWriterPool(size int) *sync.Pool {
 	switch size {
 	case 2 << 10:
-		return bufioWriterCache2k
+		return &bufioWriter2kPool
 	case 4 << 10:
-		return bufioWriterCache4k
+		return &bufioWriter4kPool
 	}
 	return nil
 }
 
 func newBufioReader(r io.Reader) *bufio.Reader {
-	select {
-	case p := <-bufioReaderCache:
-		p.Reset(r)
-		return p
-	default:
-		return bufio.NewReader(r)
+	if v := bufioReaderPool.Get(); v != nil {
+		br := v.(*bufio.Reader)
+		br.Reset(r)
+		return br
 	}
+	return bufio.NewReader(r)
 }
 
 func putBufioReader(br *bufio.Reader) {
 	br.Reset(nil)
-	select {
-	case bufioReaderCache <- br:
-	default:
-	}
+	bufioReaderPool.Put(br)
 }
 
 func newBufioWriterSize(w io.Writer, size int) *bufio.Writer {
-	select {
-	case p := <-bufioWriterCache(size):
-		p.Reset(w)
-		return p
-	default:
-		return bufio.NewWriterSize(w, size)
+	pool := bufioWriterPool(size)
+	if pool != nil {
+		if v := pool.Get(); v != nil {
+			bw := v.(*bufio.Writer)
+			bw.Reset(w)
+			return bw
+		}
 	}
+	return bufio.NewWriterSize(w, size)
 }
 
 func putBufioWriter(bw *bufio.Writer) {
 	bw.Reset(nil)
-	select {
-	case bufioWriterCache(bw.Available()) <- bw:
-	default:
+	if pool := bufioWriterPool(bw.Available()); pool != nil {
+		pool.Put(bw)
 	}
 }
 
@@ -1202,7 +1198,14 @@ func (w *response) Hijack() (rwc net.Conn, buf *bufio.ReadWriter, err error) {
 	if w.wroteHeader {
 		w.cw.flush()
 	}
-	return w.conn.hijack()
+	// Release the bufioWriter that writes to the chunk writer, it is not
+	// used after a connection has been hijacked.
+	rwc, buf, err = w.conn.hijack()
+	if err == nil {
+		putBufioWriter(w.w)
+		w.w = nil
+	}
+	return rwc, buf, err
 }
 
 func (w *response) CloseNotify() <-chan bool {
diff --git a/libgo/go/net/http/transfer.go b/libgo/go/net/http/transfer.go
index bacd83732de..4a2bda19fac 100644
--- a/libgo/go/net/http/transfer.go
+++ b/libgo/go/net/http/transfer.go
@@ -14,6 +14,7 @@ import (
 	"net/textproto"
 	"strconv"
 	"strings"
+	"sync"
 )
 
 // transferWriter inspects the fields of a user-supplied Request or Response,
@@ -331,17 +332,17 @@ func readTransfer(msg interface{}, r *bufio.Reader) (err error) {
 		if noBodyExpected(t.RequestMethod) {
 			t.Body = eofReader
 		} else {
-			t.Body = &body{Reader: newChunkedReader(r), hdr: msg, r: r, closing: t.Close}
+			t.Body = &body{src: newChunkedReader(r), hdr: msg, r: r, closing: t.Close}
 		}
 	case realLength == 0:
 		t.Body = eofReader
 	case realLength > 0:
-		t.Body = &body{Reader: io.LimitReader(r, realLength), closing: t.Close}
+		t.Body = &body{src: io.LimitReader(r, realLength), closing: t.Close}
 	default:
 		// realLength < 0, i.e. "Content-Length" not mentioned in header
 		if t.Close {
 			// Close semantics (i.e. HTTP/1.0)
-			t.Body = &body{Reader: r, closing: t.Close}
+			t.Body = &body{src: r, closing: t.Close}
 		} else {
 			// Persistent connection (i.e. HTTP/1.1)
 			t.Body = eofReader
@@ -514,11 +515,13 @@ func fixTrailer(header Header, te []string) (Header, error) {
 // Close ensures that the body has been fully read
 // and then reads the trailer if necessary.
 type body struct {
-	io.Reader
+	src     io.Reader
 	hdr     interface{}   // non-nil (Response or Request) value means read trailer
 	r       *bufio.Reader // underlying wire-format reader for the trailer
 	closing bool          // is the connection to be closed after reading body?
-	closed  bool
+
+	mu     sync.Mutex // guards closed, and calls to Read and Close
+	closed bool
 }
 
 // ErrBodyReadAfterClose is returned when reading a Request or Response
@@ -528,10 +531,17 @@ type body struct {
 var ErrBodyReadAfterClose = errors.New("http: invalid Read on closed Body")
 
 func (b *body) Read(p []byte) (n int, err error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
 	if b.closed {
 		return 0, ErrBodyReadAfterClose
 	}
-	n, err = b.Reader.Read(p)
+	return b.readLocked(p)
+}
+
+// Must hold b.mu.
+func (b *body) readLocked(p []byte) (n int, err error) {
+	n, err = b.src.Read(p)
 
 	if err == io.EOF {
 		// Chunked case. Read the trailer.
@@ -543,7 +553,7 @@ func (b *body) Read(p []byte) (n int, err error) {
 		} else {
 			// If the server declared the Content-Length, our body is a LimitedReader
 			// and we need to check whether this EOF arrived early.
-			if lr, ok := b.Reader.(*io.LimitedReader); ok && lr.N > 0 {
+			if lr, ok := b.src.(*io.LimitedReader); ok && lr.N > 0 {
 				err = io.ErrUnexpectedEOF
 			}
 		}
@@ -618,6 +628,8 @@ func (b *body) readTrailer() error {
 }
 
 func (b *body) Close() error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
 	if b.closed {
 		return nil
 	}
@@ -629,12 +641,25 @@ func (b *body) Close() error {
 	default:
 		// Fully consume the body, which will also lead to us reading
 		// the trailer headers after the body, if present.
-		_, err = io.Copy(ioutil.Discard, b)
+		_, err = io.Copy(ioutil.Discard, bodyLocked{b})
 	}
 	b.closed = true
 	return err
 }
 
+// bodyLocked is a io.Reader reading from a *body when its mutex is
+// already held.
+type bodyLocked struct {
+	b *body
+}
+
+func (bl bodyLocked) Read(p []byte) (n int, err error) {
+	if bl.b.closed {
+		return 0, ErrBodyReadAfterClose
+	}
+	return bl.b.readLocked(p)
+}
+
 // parseContentLength trims whitespace from s and returns -1 if no value
 // is set, or the value if it's >= 0.
 func parseContentLength(cl string) (int64, error) {
diff --git a/libgo/go/net/http/transfer_test.go b/libgo/go/net/http/transfer_test.go
index 8627a374c8f..fb5ef37a0f0 100644
--- a/libgo/go/net/http/transfer_test.go
+++ b/libgo/go/net/http/transfer_test.go
@@ -12,9 +12,9 @@ import (
 
 func TestBodyReadBadTrailer(t *testing.T) {
 	b := &body{
-		Reader: strings.NewReader("foobar"),
-		hdr:    true, // force reading the trailer
-		r:      bufio.NewReader(strings.NewReader("")),
+		src: strings.NewReader("foobar"),
+		hdr: true, // force reading the trailer
+		r:   bufio.NewReader(strings.NewReader("")),
 	}
 	buf := make([]byte, 7)
 	n, err := b.Read(buf[:3])
diff --git a/libgo/go/net/http/transport_test.go b/libgo/go/net/http/transport_test.go
index e4df30a98de..2ce2b6b5180 100644
--- a/libgo/go/net/http/transport_test.go
+++ b/libgo/go/net/http/transport_test.go
@@ -798,8 +798,8 @@ func TestTransportPersistConnLeak(t *testing.T) {
 
 	// We expect 0 or 1 extra goroutine, empirically.  Allow up to 5.
 	// Previously we were leaking one per numReq.
-	t.Logf("goroutine growth: %d -> %d -> %d (delta: %d)", n0, nhigh, nfinal, growth)
 	if int(growth) > 5 {
+		t.Logf("goroutine growth: %d -> %d -> %d (delta: %d)", n0, nhigh, nfinal, growth)
 		t.Error("too many new goroutines")
 	}
 }