libgo: Update Go library to master revision 15489/921e53d4863c.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@195560 138bc75d-0d04-0410-961f-82ee72b054a4

47 files changed, 1025 insertions, 704 deletions

diff --git a/libgo/go/net/dial.go b/libgo/go/net/dial.go
index c1eb983cc0f..354028a157a 100644
--- a/libgo/go/net/dial.go
+++ b/libgo/go/net/dial.go
@@ -5,7 +5,6 @@
 package net
 
 import (
-	"runtime"
 	"time"
 )
 
@@ -113,30 +112,16 @@ func dialAddr(net, addr string, addri Addr, deadline time.Time) (c Conn, err err
 	return
 }
 
-const useDialTimeoutRace = runtime.GOOS == "windows" || runtime.GOOS == "plan9"
-
 // DialTimeout acts like Dial but takes a timeout.
 // The timeout includes name resolution, if required.
 func DialTimeout(net, addr string, timeout time.Duration) (Conn, error) {
-	if useDialTimeoutRace {
-		// On windows and plan9, use the relatively inefficient
-		// goroutine-racing implementation of DialTimeout that
-		// doesn't push down deadlines to the pollster.
-		// TODO: remove this once those are implemented.
-		return dialTimeoutRace(net, addr, timeout)
-	}
-	deadline := time.Now().Add(timeout)
-	_, addri, err := resolveNetAddr("dial", net, addr, deadline)
-	if err != nil {
-		return nil, err
-	}
-	return dialAddr(net, addr, addri, deadline)
+	return dialTimeout(net, addr, timeout)
 }
 
 // dialTimeoutRace is the old implementation of DialTimeout, still used
 // on operating systems where the deadline hasn't been pushed down
 // into the pollserver.
-// TODO: fix this on Windows and plan9.
+// TODO: fix this on plan9.
 func dialTimeoutRace(net, addr string, timeout time.Duration) (Conn, error) {
 	t := time.NewTimer(timeout)
 	defer t.Stop()
diff --git a/libgo/go/net/dial_test.go b/libgo/go/net/dial_test.go
index f30dee30164..aa53b667ded 100644
--- a/libgo/go/net/dial_test.go
+++ b/libgo/go/net/dial_test.go
@@ -74,8 +74,7 @@ func TestDialTimeout(t *testing.T) {
 		// by default. FreeBSD likely works, but is untested.
 		// TODO(rsc):
 		// The timeout never happens on Windows.  Why?  Issue 3016.
-		t.Logf("skipping test on %q; untested.", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q; untested.", runtime.GOOS)
 	}
 
 	connected := 0
@@ -107,8 +106,7 @@ func TestDialTimeout(t *testing.T) {
 func TestSelfConnect(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		// TODO(brainman): do not know why it hangs.
-		t.Logf("skipping known-broken test on windows")
-		return
+		t.Skip("skipping known-broken test on windows")
 	}
 	// Test that Dial does not honor self-connects.
 	// See the comment in DialTCP.
@@ -228,8 +226,7 @@ func TestDialError(t *testing.T) {
 func TestDialTimeoutFDLeak(t *testing.T) {
 	if runtime.GOOS != "linux" {
 		// TODO(bradfitz): test on other platforms
-		t.Logf("skipping test on %s", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	ln := newLocalListener(t)
diff --git a/libgo/go/net/dialgoogle_test.go b/libgo/go/net/dialgoogle_test.go
index dd3c4ba7e15..73a94f5bf1c 100644
--- a/libgo/go/net/dialgoogle_test.go
+++ b/libgo/go/net/dialgoogle_test.go
@@ -56,8 +56,7 @@ var googleaddrsipv4 = []string{
 
 func TestDialGoogleIPv4(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 
 	// Insert an actual IPv4 address for google.com
@@ -112,17 +111,14 @@ var googleaddrsipv6 = []string{
 
 func TestDialGoogleIPv6(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	// Only run tcp6 if the kernel will take it.
 	if !supportsIPv6 {
-		t.Logf("skipping test; ipv6 is not supported")
-		return
+		t.Skip("skipping test; ipv6 is not supported")
 	}
 	if !*testIPv6 {
-		t.Logf("test disabled; use -ipv6 to enable")
-		return
+		t.Skip("test disabled; use -ipv6 to enable")
 	}
 
 	// Insert an actual IPv6 address for ipv6.google.com
diff --git a/libgo/go/net/fd_netbsd.go b/libgo/go/net/fd_bsd.go
index 35d84c30ef6..4f5dd6e524a 100644
--- a/libgo/go/net/fd_netbsd.go
+++ b/libgo/go/net/fd_bsd.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build freebsd netbsd openbsd
+
 // Waiting for FDs via kqueue/kevent.
 
 package net
diff --git a/libgo/go/net/fd_openbsd.go b/libgo/go/net/fd_openbsd.go
deleted file mode 100644
index 35d84c30ef6..00000000000
--- a/libgo/go/net/fd_openbsd.go
+++ /dev/null
@@ -1,116 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Waiting for FDs via kqueue/kevent.
-
-package net
-
-import (
-	"os"
-	"syscall"
-)
-
-type pollster struct {
-	kq       int
-	eventbuf [10]syscall.Kevent_t
-	events   []syscall.Kevent_t
-
-	// An event buffer for AddFD/DelFD.
-	// Must hold pollServer lock.
-	kbuf [1]syscall.Kevent_t
-}
-
-func newpollster() (p *pollster, err error) {
-	p = new(pollster)
-	if p.kq, err = syscall.Kqueue(); err != nil {
-		return nil, os.NewSyscallError("kqueue", err)
-	}
-	syscall.CloseOnExec(p.kq)
-	p.events = p.eventbuf[0:0]
-	return p, nil
-}
-
-func (p *pollster) AddFD(fd int, mode int, repeat bool) (bool, error) {
-	// pollServer is locked.
-
-	var kmode int
-	if mode == 'r' {
-		kmode = syscall.EVFILT_READ
-	} else {
-		kmode = syscall.EVFILT_WRITE
-	}
-	ev := &p.kbuf[0]
-	// EV_ADD - add event to kqueue list
-	// EV_ONESHOT - delete the event the first time it triggers
-	flags := syscall.EV_ADD
-	if !repeat {
-		flags |= syscall.EV_ONESHOT
-	}
-	syscall.SetKevent(ev, fd, kmode, flags)
-
-	n, err := syscall.Kevent(p.kq, p.kbuf[:], nil, nil)
-	if err != nil {
-		return false, os.NewSyscallError("kevent", err)
-	}
-	if n != 1 || (ev.Flags&syscall.EV_ERROR) == 0 || int(ev.Ident) != fd || int(ev.Filter) != kmode {
-		return false, os.NewSyscallError("kqueue phase error", err)
-	}
-	if ev.Data != 0 {
-		return false, syscall.Errno(int(ev.Data))
-	}
-	return false, nil
-}
-
-func (p *pollster) DelFD(fd int, mode int) {
-	// pollServer is locked.
-
-	var kmode int
-	if mode == 'r' {
-		kmode = syscall.EVFILT_READ
-	} else {
-		kmode = syscall.EVFILT_WRITE
-	}
-	ev := &p.kbuf[0]
-	// EV_DELETE - delete event from kqueue list
-	syscall.SetKevent(ev, fd, kmode, syscall.EV_DELETE)
-	syscall.Kevent(p.kq, p.kbuf[:], nil, nil)
-}
-
-func (p *pollster) WaitFD(s *pollServer, nsec int64) (fd int, mode int, err error) {
-	var t *syscall.Timespec
-	for len(p.events) == 0 {
-		if nsec > 0 {
-			if t == nil {
-				t = new(syscall.Timespec)
-			}
-			*t = syscall.NsecToTimespec(nsec)
-		}
-
-		s.Unlock()
-		n, err := syscall.Kevent(p.kq, nil, p.eventbuf[:], t)
-		s.Lock()
-
-		if err != nil {
-			if err == syscall.EINTR {
-				continue
-			}
-			return -1, 0, os.NewSyscallError("kevent", err)
-		}
-		if n == 0 {
-			return -1, 0, nil
-		}
-		p.events = p.eventbuf[:n]
-	}
-	ev := &p.events[0]
-	p.events = p.events[1:]
-	fd = int(ev.Ident)
-	if ev.Filter == syscall.EVFILT_READ {
-		mode = 'r'
-	} else {
-		mode = 'w'
-	}
-	return fd, mode, nil
-}
-
-func (p *pollster) Close() error { return os.NewSyscallError("close", syscall.Close(p.kq)) }
diff --git a/libgo/go/net/fd_plan9.go b/libgo/go/net/fd_plan9.go
index 6d7ab388ae7..3462792816e 100644
--- a/libgo/go/net/fd_plan9.go
+++ b/libgo/go/net/fd_plan9.go
@@ -23,6 +23,12 @@ var canCancelIO = true // used for testing current package
 func sysInit() {
 }
 
+func dialTimeout(net, addr string, timeout time.Duration) (Conn, error) {
+	// On plan9, use the relatively inefficient
+	// goroutine-racing implementation.
+	return dialTimeoutRace(net, addr, timeout)
+}
+
 func newFD(proto, name string, ctl *os.File, laddr, raddr Addr) *netFD {
 	return &netFD{proto, name, "/net/" + proto + "/" + name, ctl, nil, laddr, raddr}
 }
diff --git a/libgo/go/net/fd_unix.go b/libgo/go/net/fd_unix.go
index 6d8af0ab2e2..e9d2e4165f1 100644
--- a/libgo/go/net/fd_unix.go
+++ b/libgo/go/net/fd_unix.go
@@ -288,10 +288,16 @@ func server(fd int) *pollServer {
 	return pollservers[k]
 }
 
-func newFD(fd, family, sotype int, net string) (*netFD, error) {
-	if err := syscall.SetNonblock(fd, true); err != nil {
+func dialTimeout(net, addr string, timeout time.Duration) (Conn, error) {
+	deadline := time.Now().Add(timeout)
+	_, addri, err := resolveNetAddr("dial", net, addr, deadline)
+	if err != nil {
 		return nil, err
 	}
+	return dialAddr(net, addr, addri, deadline)
+}
+
+func newFD(fd, family, sotype int, net string) (*netFD, error) {
 	netfd := &netFD{
 		sysfd:  fd,
 		family: family,
@@ -606,16 +612,11 @@ func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (netfd *netFD, err e
 	}
 	defer fd.decref()
 
-	// See ../syscall/exec_unix.go for description of ForkLock.
-	// It is okay to hold the lock across syscall.Accept
-	// because we have put fd.sysfd into non-blocking mode.
 	var s int
 	var rsa syscall.Sockaddr
 	for {
-		syscall.ForkLock.RLock()
-		s, rsa, err = syscall.Accept(fd.sysfd)
+		s, rsa, err = accept(fd.sysfd)
 		if err != nil {
-			syscall.ForkLock.RUnlock()
 			if err == syscall.EAGAIN {
 				if err = fd.pollServer.WaitRead(fd); err == nil {
 					continue
@@ -629,8 +630,6 @@ func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (netfd *netFD, err e
 		}
 		break
 	}
-	syscall.CloseOnExec(s)
-	syscall.ForkLock.RUnlock()
 
 	if netfd, err = newFD(s, fd.family, fd.sotype, fd.net); err != nil {
 		closesocket(s)
diff --git a/libgo/go/net/fd_windows.go b/libgo/go/net/fd_windows.go
index 18712191fee..ea6ef10ec1a 100644
--- a/libgo/go/net/fd_windows.go
+++ b/libgo/go/net/fd_windows.go
@@ -45,6 +45,28 @@ func closesocket(s syscall.Handle) error {
 	return syscall.Closesocket(s)
 }
 
+func canUseConnectEx(net string) bool {
+	if net == "udp" || net == "udp4" || net == "udp6" {
+		// ConnectEx windows API does not support connectionless sockets.
+		return false
+	}
+	return syscall.LoadConnectEx() == nil
+}
+
+func dialTimeout(net, addr string, timeout time.Duration) (Conn, error) {
+	if !canUseConnectEx(net) {
+		// Use the relatively inefficient goroutine-racing
+		// implementation of DialTimeout.
+		return dialTimeoutRace(net, addr, timeout)
+	}
+	deadline := time.Now().Add(timeout)
+	_, addri, err := resolveNetAddr("dial", net, addr, deadline)
+	if err != nil {
+		return nil, err
+	}
+	return dialAddr(net, addr, addri, deadline)
+}
+
 // Interface for all IO operations.
 type anOpIface interface {
 	Op() *anOp
@@ -321,8 +343,48 @@ func (fd *netFD) setAddr(laddr, raddr Addr) {
 	runtime.SetFinalizer(fd, (*netFD).closesocket)
 }
 
+// Make new connection.
+
+type connectOp struct {
+	anOp
+	ra syscall.Sockaddr
+}
+
+func (o *connectOp) Submit() error {
+	return syscall.ConnectEx(o.fd.sysfd, o.ra, nil, 0, nil, &o.o)
+}
+
+func (o *connectOp) Name() string {
+	return "ConnectEx"
+}
+
 func (fd *netFD) connect(ra syscall.Sockaddr) error {
-	return syscall.Connect(fd.sysfd, ra)
+	if !canUseConnectEx(fd.net) {
+		return syscall.Connect(fd.sysfd, ra)
+	}
+	// ConnectEx windows API requires an unconnected, previously bound socket.
+	var la syscall.Sockaddr
+	switch ra.(type) {
+	case *syscall.SockaddrInet4:
+		la = &syscall.SockaddrInet4{}
+	case *syscall.SockaddrInet6:
+		la = &syscall.SockaddrInet6{}
+	default:
+		panic("unexpected type in connect")
+	}
+	if err := syscall.Bind(fd.sysfd, la); err != nil {
+		return err
+	}
+	// Call ConnectEx API.
+	var o connectOp
+	o.Init(fd, 'w')
+	o.ra = ra
+	_, err := iosrv.ExecIO(&o, fd.wdeadline.value())
+	if err != nil {
+		return err
+	}
+	// Refresh socket properties.
+	return syscall.Setsockopt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_UPDATE_CONNECT_CONTEXT, (*byte)(unsafe.Pointer(&fd.sysfd)), int32(unsafe.Sizeof(fd.sysfd)))
 }
 
 // Add a reference to this fd.
diff --git a/libgo/go/net/file_test.go b/libgo/go/net/file_test.go
index 95c0b66995e..78c62221dae 100644
--- a/libgo/go/net/file_test.go
+++ b/libgo/go/net/file_test.go
@@ -90,8 +90,7 @@ var fileListenerTests = []struct {
 func TestFileListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	for _, tt := range fileListenerTests {
@@ -181,8 +180,7 @@ var filePacketConnTests = []struct {
 func TestFilePacketConn(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	for _, tt := range filePacketConnTests {
diff --git a/libgo/go/net/file_unix.go b/libgo/go/net/file_unix.go
index 0a640801779..4c8403e4063 100644
--- a/libgo/go/net/file_unix.go
+++ b/libgo/go/net/file_unix.go
@@ -20,6 +20,10 @@ func newFileFD(f *os.File) (*netFD, error) {
 	}
 	syscall.CloseOnExec(fd)
 	syscall.ForkLock.RUnlock()
+	if err = syscall.SetNonblock(fd, true); err != nil {
+		closesocket(fd)
+		return nil, err
+	}
 
 	sotype, err := syscall.GetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_TYPE)
 	if err != nil {
diff --git a/libgo/go/net/http/cgi/child.go b/libgo/go/net/http/cgi/child.go
index 1ba7bec5fc5..100b8b77760 100644
--- a/libgo/go/net/http/cgi/child.go
+++ b/libgo/go/net/http/cgi/child.go
@@ -91,10 +91,19 @@ func RequestFromMap(params map[string]string) (*http.Request, error) {
 
 	// TODO: cookies.  parsing them isn't exported, though.
 
+	uriStr := params["REQUEST_URI"]
+	if uriStr == "" {
+		// Fallback to SCRIPT_NAME, PATH_INFO and QUERY_STRING.
+		uriStr = params["SCRIPT_NAME"] + params["PATH_INFO"]
+		s := params["QUERY_STRING"]
+		if s != "" {
+			uriStr += "?" + s
+		}
+	}
 	if r.Host != "" {
 		// Hostname is provided, so we can reasonably construct a URL,
 		// even if we have to assume 'http' for the scheme.
-		rawurl := "http://" + r.Host + params["REQUEST_URI"]
+		rawurl := "http://" + r.Host + uriStr
 		url, err := url.Parse(rawurl)
 		if err != nil {
 			return nil, errors.New("cgi: failed to parse host and REQUEST_URI into a URL: " + rawurl)
@@ -104,7 +113,6 @@ func RequestFromMap(params map[string]string) (*http.Request, error) {
 	// Fallback logic if we don't have a Host header or the URL
 	// failed to parse
 	if r.URL == nil {
-		uriStr := params["REQUEST_URI"]
 		url, err := url.Parse(uriStr)
 		if err != nil {
 			return nil, errors.New("cgi: failed to parse REQUEST_URI into a URL: " + uriStr)
diff --git a/libgo/go/net/http/cgi/child_test.go b/libgo/go/net/http/cgi/child_test.go
index ec53ab851ba..74e068014bb 100644
--- a/libgo/go/net/http/cgi/child_test.go
+++ b/libgo/go/net/http/cgi/child_test.go
@@ -82,6 +82,28 @@ func TestRequestWithoutHost(t *testing.T) {
 		t.Fatalf("unexpected nil URL")
 	}
 	if g, e := req.URL.String(), "/path?a=b"; e != g {
-		t.Errorf("expected URL %q; got %q", e, g)
+		t.Errorf("URL = %q; want %q", g, e)
+	}
+}
+
+func TestRequestWithoutRequestURI(t *testing.T) {
+	env := map[string]string{
+		"SERVER_PROTOCOL": "HTTP/1.1",
+		"HTTP_HOST":       "example.com",
+		"REQUEST_METHOD":  "GET",
+		"SCRIPT_NAME":     "/dir/scriptname",
+		"PATH_INFO":       "/p1/p2",
+		"QUERY_STRING":    "a=1&b=2",
+		"CONTENT_LENGTH":  "123",
+	}
+	req, err := RequestFromMap(env)
+	if err != nil {
+		t.Fatalf("RequestFromMap: %v", err)
+	}
+	if req.URL == nil {
+		t.Fatalf("unexpected nil URL")
+	}
+	if g, e := req.URL.String(), "http://example.com/dir/scriptname/p1/p2?a=1&b=2"; e != g {
+		t.Errorf("URL = %q; want %q", g, e)
 	}
 }
diff --git a/libgo/go/net/http/cgi/host_test.go b/libgo/go/net/http/cgi/host_test.go
index 85b52c9fdbc..cb6f1df1f45 100644
--- a/libgo/go/net/http/cgi/host_test.go
+++ b/libgo/go/net/http/cgi/host_test.go
@@ -63,17 +63,25 @@ readlines:
 	}
 
 	for key, expected := range expectedMap {
-		if got := m[key]; got != expected {
+		got := m[key]
+		if key == "cwd" {
+			// For Windows. golang.org/issue/4645.
+			fi1, _ := os.Stat(got)
+			fi2, _ := os.Stat(expected)
+			if os.SameFile(fi1, fi2) {
+				got = expected
+			}
+		}
+		if got != expected {
 			t.Errorf("for key %q got %q; expected %q", key, got, expected)
 		}
 	}
 	return rw
 }
 
-var cgiTested = false
-var cgiWorks bool
+var cgiTested, cgiWorks bool
 
-func skipTest(t *testing.T) bool {
+func check(t *testing.T) {
 	if !cgiTested {
 		cgiTested = true
 		cgiWorks = exec.Command("./testdata/test.cgi").Run() == nil
@@ -81,16 +89,12 @@ func skipTest(t *testing.T) bool {
 	if !cgiWorks {
 		// No Perl on Windows, needed by test.cgi
 		// TODO: make the child process be Go, not Perl.
-		t.Logf("Skipping test: test.cgi failed.")
-		return true
+		t.Skip("Skipping test: test.cgi failed.")
 	}
-	return false
 }
 
 func TestCGIBasicGet(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 		Root: "/test.cgi",
@@ -124,9 +128,7 @@ func TestCGIBasicGet(t *testing.T) {
 }
 
 func TestCGIBasicGetAbsPath(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	pwd, err := os.Getwd()
 	if err != nil {
 		t.Fatalf("getwd error: %v", err)
@@ -144,9 +146,7 @@ func TestCGIBasicGetAbsPath(t *testing.T) {
 }
 
 func TestPathInfo(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 		Root: "/test.cgi",
@@ -163,9 +163,7 @@ func TestPathInfo(t *testing.T) {
 }
 
 func TestPathInfoDirRoot(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 		Root: "/myscript/",
@@ -181,9 +179,7 @@ func TestPathInfoDirRoot(t *testing.T) {
 }
 
 func TestDupHeaders(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 	}
@@ -203,9 +199,7 @@ func TestDupHeaders(t *testing.T) {
 }
 
 func TestPathInfoNoRoot(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 		Root: "",
@@ -221,9 +215,7 @@ func TestPathInfoNoRoot(t *testing.T) {
 }
 
 func TestCGIBasicPost(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	postReq := `POST /test.cgi?a=b HTTP/1.0
 Host: example.com
 Content-Type: application/x-www-form-urlencoded
@@ -250,9 +242,7 @@ func chunk(s string) string {
 
 // The CGI spec doesn't allow chunked requests.
 func TestCGIPostChunked(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	postReq := `POST /test.cgi?a=b HTTP/1.1
 Host: example.com
 Content-Type: application/x-www-form-urlencoded
@@ -273,9 +263,7 @@ Transfer-Encoding: chunked
 }
 
 func TestRedirect(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	h := &Handler{
 		Path: "testdata/test.cgi",
 		Root: "/test.cgi",
@@ -290,9 +278,7 @@ func TestRedirect(t *testing.T) {
 }
 
 func TestInternalRedirect(t *testing.T) {
-	if skipTest(t) {
-		return
-	}
+	check(t)
 	baseHandler := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		fmt.Fprintf(rw, "basepath=%s\n", req.URL.Path)
 		fmt.Fprintf(rw, "remoteaddr=%s\n", req.RemoteAddr)
@@ -312,8 +298,9 @@ func TestInternalRedirect(t *testing.T) {
 // TestCopyError tests that we kill the process if there's an error copying
 // its output. (for example, from the client having gone away)
 func TestCopyError(t *testing.T) {
-	if skipTest(t) || runtime.GOOS == "windows" {
-		return
+	check(t)
+	if runtime.GOOS == "windows" {
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	h := &Handler{
 		Path: "testdata/test.cgi",
@@ -376,10 +363,10 @@ func TestCopyError(t *testing.T) {
 }
 
 func TestDirUnix(t *testing.T) {
-	if skipTest(t) || runtime.GOOS == "windows" {
-		return
+	check(t)
+	if runtime.GOOS == "windows" {
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
-
 	cwd, _ := os.Getwd()
 	h := &Handler{
 		Path: "testdata/test.cgi",
@@ -406,8 +393,7 @@ func TestDirUnix(t *testing.T) {
 
 func TestDirWindows(t *testing.T) {
 	if runtime.GOOS != "windows" {
-		t.Logf("Skipping windows specific test.")
-		return
+		t.Skip("Skipping windows specific test.")
 	}
 
 	cgifile, _ := filepath.Abs("testdata/test.cgi")
@@ -416,8 +402,7 @@ func TestDirWindows(t *testing.T) {
 	var err error
 	perl, err = exec.LookPath("perl")
 	if err != nil {
-		t.Logf("Skipping test: perl not found.")
-		return
+		t.Skip("Skipping test: perl not found.")
 	}
 	perl, _ = filepath.Abs(perl)
 
@@ -459,8 +444,7 @@ func TestEnvOverride(t *testing.T) {
 	var err error
 	perl, err = exec.LookPath("perl")
 	if err != nil {
-		t.Logf("Skipping test: perl not found.")
-		return
+		t.Skipf("Skipping test: perl not found.")
 	}
 	perl, _ = filepath.Abs(perl)
 
diff --git a/libgo/go/net/http/fs_test.go b/libgo/go/net/http/fs_test.go
index 59e30a19fca..d42014c265b 100644
--- a/libgo/go/net/http/fs_test.go
+++ b/libgo/go/net/http/fs_test.go
@@ -257,8 +257,7 @@ func TestFileServerImplicitLeadingSlash(t *testing.T) {
 func TestDirJoin(t *testing.T) {
 	wfi, err := os.Stat("/etc/hosts")
 	if err != nil {
-		t.Logf("skipping test; no /etc/hosts file")
-		return
+		t.Skip("skipping test; no /etc/hosts file")
 	}
 	test := func(d Dir, name string) {
 		f, err := d.Open(name)
@@ -665,13 +664,10 @@ func TestServeContent(t *testing.T) {
 // verifies that sendfile is being used on Linux
 func TestLinuxSendfile(t *testing.T) {
 	if runtime.GOOS != "linux" {
-		t.Logf("skipping; linux-only test")
-		return
+		t.Skip("skipping; linux-only test")
 	}
-	_, err := exec.LookPath("strace")
-	if err != nil {
-		t.Logf("skipping; strace not found in path")
-		return
+	if _, err := exec.LookPath("strace"); err != nil {
+		t.Skip("skipping; strace not found in path")
 	}
 
 	ln, err := net.Listen("tcp", "127.0.0.1:0")
@@ -690,10 +686,8 @@ func TestLinuxSendfile(t *testing.T) {
 	child.Env = append([]string{"GO_WANT_HELPER_PROCESS=1"}, os.Environ()...)
 	child.Stdout = &buf
 	child.Stderr = &buf
-	err = child.Start()
-	if err != nil {
-		t.Logf("skipping; failed to start straced child: %v", err)
-		return
+	if err := child.Start(); err != nil {
+		t.Skipf("skipping; failed to start straced child: %v", err)
 	}
 
 	res, err := Get(fmt.Sprintf("http://%s/", ln.Addr()))
diff --git a/libgo/go/net/http/header.go b/libgo/go/net/http/header.go
index 91417366ae8..f479b7b4eb9 100644
--- a/libgo/go/net/http/header.go
+++ b/libgo/go/net/http/header.go
@@ -54,6 +54,16 @@ func (h Header) Write(w io.Writer) error {
 	return h.WriteSubset(w, nil)
 }
 
+func (h Header) clone() Header {
+	h2 := make(Header, len(h))
+	for k, vv := range h {
+		vv2 := make([]string, len(vv))
+		copy(vv2, vv)
+		h2[k] = vv2
+	}
+	return h2
+}
+
 var timeFormats = []string{
 	TimeFormat,
 	time.RFC850,
diff --git a/libgo/go/net/http/proxy_test.go b/libgo/go/net/http/proxy_test.go
index 86db976b838..449ccaeea76 100644
--- a/libgo/go/net/http/proxy_test.go
+++ b/libgo/go/net/http/proxy_test.go
@@ -31,7 +31,7 @@ var UseProxyTests = []struct {
 	{"localhost.net", true},   // not match as suffix of address
 	{"local.localhost", true}, // not match as prefix as address
 	{"barbarbaz.net", true},   // not match because NO_PROXY have a '.'
-	{"www.foobar.com", true},  // not match because NO_PROXY is not .foobar.com
+	{"www.foobar.com", false}, // match because NO_PROXY includes "foobar.com"
 }
 
 func TestUseProxy(t *testing.T) {
diff --git a/libgo/go/net/http/request.go b/libgo/go/net/http/request.go
index 0b6e6cbab58..217f35b4833 100644
--- a/libgo/go/net/http/request.go
+++ b/libgo/go/net/http/request.go
@@ -71,7 +71,13 @@ var reqWriteExcludeHeader = map[string]bool{
 // or to be sent by a client.
 type Request struct {
 	Method string // GET, POST, PUT, etc.
-	URL    *url.URL
+
+	// URL is created from the URI supplied on the Request-Line
+	// as stored in RequestURI.
+	//
+	// For most requests, fields other than Path and RawQuery
+	// will be empty. (See RFC 2616, Section 5.1.2)
+	URL *url.URL
 
 	// The protocol version for incoming requests.
 	// Outgoing requests always use HTTP/1.1.
@@ -325,11 +331,20 @@ func (req *Request) write(w io.Writer, usingProxy bool, extraHeaders Header) err
 	}
 	// TODO(bradfitz): escape at least newlines in ruri?
 
-	bw := bufio.NewWriter(w)
-	fmt.Fprintf(bw, "%s %s HTTP/1.1\r\n", valueOrDefault(req.Method, "GET"), ruri)
+	// Wrap the writer in a bufio Writer if it's not already buffered.
+	// Don't always call NewWriter, as that forces a bytes.Buffer
+	// and other small bufio Writers to have a minimum 4k buffer
+	// size.
+	var bw *bufio.Writer
+	if _, ok := w.(io.ByteWriter); !ok {
+		bw = bufio.NewWriter(w)
+		w = bw
+	}
+
+	fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(req.Method, "GET"), ruri)
 
 	// Header lines
-	fmt.Fprintf(bw, "Host: %s\r\n", host)
+	fmt.Fprintf(w, "Host: %s\r\n", host)
 
 	// Use the defaultUserAgent unless the Header contains one, which
 	// may be blank to not send the header.
@@ -340,7 +355,7 @@ func (req *Request) write(w io.Writer, usingProxy bool, extraHeaders Header) err
 		}
 	}
 	if userAgent != "" {
-		fmt.Fprintf(bw, "User-Agent: %s\r\n", userAgent)
+		fmt.Fprintf(w, "User-Agent: %s\r\n", userAgent)
 	}
 
 	// Process Body,ContentLength,Close,Trailer
@@ -348,33 +363,36 @@ func (req *Request) write(w io.Writer, usingProxy bool, extraHeaders Header) err
 	if err != nil {
 		return err
 	}
-	err = tw.WriteHeader(bw)
+	err = tw.WriteHeader(w)
 	if err != nil {
 		return err
 	}
 
 	// TODO: split long values?  (If so, should share code with Conn.Write)
-	err = req.Header.WriteSubset(bw, reqWriteExcludeHeader)
+	err = req.Header.WriteSubset(w, reqWriteExcludeHeader)
 	if err != nil {
 		return err
 	}
 
 	if extraHeaders != nil {
-		err = extraHeaders.Write(bw)
+		err = extraHeaders.Write(w)
 		if err != nil {
 			return err
 		}
 	}
 
-	io.WriteString(bw, "\r\n")
+	io.WriteString(w, "\r\n")
 
 	// Write body and trailer
-	err = tw.WriteBody(bw)
+	err = tw.WriteBody(w)
 	if err != nil {
 		return err
 	}
 
-	return bw.Flush()
+	if bw != nil {
+		return bw.Flush()
+	}
+	return nil
 }
 
 // ParseHTTPVersion parses a HTTP version string.
@@ -427,10 +445,12 @@ func NewRequest(method, urlStr string, body io.Reader) (*Request, error) {
 	}
 	if body != nil {
 		switch v := body.(type) {
-		case *strings.Reader:
-			req.ContentLength = int64(v.Len())
 		case *bytes.Buffer:
 			req.ContentLength = int64(v.Len())
+		case *bytes.Reader:
+			req.ContentLength = int64(v.Len())
+		case *strings.Reader:
+			req.ContentLength = int64(v.Len())
 		}
 	}
 
diff --git a/libgo/go/net/http/request_test.go b/libgo/go/net/http/request_test.go
index 2f34d124128..bd757920b78 100644
--- a/libgo/go/net/http/request_test.go
+++ b/libgo/go/net/http/request_test.go
@@ -238,6 +238,65 @@ func TestNewRequestHost(t *testing.T) {
 	}
 }
 
+func TestNewRequestContentLength(t *testing.T) {
+	readByte := func(r io.Reader) io.Reader {
+		var b [1]byte
+		r.Read(b[:])
+		return r
+	}
+	tests := []struct {
+		r    io.Reader
+		want int64
+	}{
+		{bytes.NewReader([]byte("123")), 3},
+		{bytes.NewBuffer([]byte("1234")), 4},
+		{strings.NewReader("12345"), 5},
+		// Not detected:
+		{struct{ io.Reader }{strings.NewReader("xyz")}, 0},
+		{io.NewSectionReader(strings.NewReader("x"), 0, 6), 0},
+		{readByte(io.NewSectionReader(strings.NewReader("xy"), 0, 6)), 0},
+	}
+	for _, tt := range tests {
+		req, err := NewRequest("POST", "http://localhost/", tt.r)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if req.ContentLength != tt.want {
+			t.Errorf("ContentLength(%#T) = %d; want %d", tt.r, req.ContentLength, tt.want)
+		}
+	}
+}
+
+type logWrites struct {
+	t   *testing.T
+	dst *[]string
+}
+
+func (l logWrites) WriteByte(c byte) error {
+	l.t.Fatalf("unexpected WriteByte call")
+	return nil
+}
+
+func (l logWrites) Write(p []byte) (n int, err error) {
+	*l.dst = append(*l.dst, string(p))
+	return len(p), nil
+}
+
+func TestRequestWriteBufferedWriter(t *testing.T) {
+	got := []string{}
+	req, _ := NewRequest("GET", "http://foo.com/", nil)
+	req.Write(logWrites{t, &got})
+	want := []string{
+		"GET / HTTP/1.1\r\n",
+		"Host: foo.com\r\n",
+		"User-Agent: Go http package\r\n",
+		"\r\n",
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Writes = %q\n  Want = %q", got, want)
+	}
+}
+
 func testMissingFile(t *testing.T, req *Request) {
 	f, fh, err := req.FormFile("missing")
 	if f != nil {
diff --git a/libgo/go/net/http/response_test.go b/libgo/go/net/http/response_test.go
index f31e5d09fe5..a00a4ae0a9b 100644
--- a/libgo/go/net/http/response_test.go
+++ b/libgo/go/net/http/response_test.go
@@ -124,7 +124,7 @@ var respTests = []respTest{
 
 	// Chunked response without Content-Length.
 	{
-		"HTTP/1.0 200 OK\r\n" +
+		"HTTP/1.1 200 OK\r\n" +
 			"Transfer-Encoding: chunked\r\n" +
 			"\r\n" +
 			"0a\r\n" +
@@ -137,12 +137,12 @@ var respTests = []respTest{
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
-			Proto:            "HTTP/1.0",
+			Proto:            "HTTP/1.1",
 			ProtoMajor:       1,
-			ProtoMinor:       0,
+			ProtoMinor:       1,
 			Request:          dummyReq("GET"),
 			Header:           Header{},
-			Close:            true,
+			Close:            false,
 			ContentLength:    -1,
 			TransferEncoding: []string{"chunked"},
 		},
@@ -152,7 +152,7 @@ var respTests = []respTest{
 
 	// Chunked response with Content-Length.
 	{
-		"HTTP/1.0 200 OK\r\n" +
+		"HTTP/1.1 200 OK\r\n" +
 			"Transfer-Encoding: chunked\r\n" +
 			"Content-Length: 10\r\n" +
 			"\r\n" +
@@ -164,12 +164,12 @@ var respTests = []respTest{
 		Response{
 			Status:           "200 OK",
 			StatusCode:       200,
-			Proto:            "HTTP/1.0",
+			Proto:            "HTTP/1.1",
 			ProtoMajor:       1,
-			ProtoMinor:       0,
+			ProtoMinor:       1,
 			Request:          dummyReq("GET"),
 			Header:           Header{},
-			Close:            true,
+			Close:            false,
 			ContentLength:    -1, // TODO(rsc): Fix?
 			TransferEncoding: []string{"chunked"},
 		},
@@ -177,23 +177,88 @@ var respTests = []respTest{
 		"Body here\n",
 	},
 
-	// Chunked response in response to a HEAD request (the "chunked" should
-	// be ignored, as HEAD responses never have bodies)
+	// Chunked response in response to a HEAD request
 	{
-		"HTTP/1.0 200 OK\r\n" +
+		"HTTP/1.1 200 OK\r\n" +
 			"Transfer-Encoding: chunked\r\n" +
 			"\r\n",
 
 		Response{
-			Status:        "200 OK",
-			StatusCode:    200,
-			Proto:         "HTTP/1.0",
-			ProtoMajor:    1,
-			ProtoMinor:    0,
-			Request:       dummyReq("HEAD"),
-			Header:        Header{},
-			Close:         true,
-			ContentLength: -1,
+			Status:           "200 OK",
+			StatusCode:       200,
+			Proto:            "HTTP/1.1",
+			ProtoMajor:       1,
+			ProtoMinor:       1,
+			Request:          dummyReq("HEAD"),
+			Header:           Header{},
+			TransferEncoding: []string{"chunked"},
+			Close:            false,
+			ContentLength:    -1,
+		},
+
+		"",
+	},
+
+	// Content-Length in response to a HEAD request
+	{
+		"HTTP/1.0 200 OK\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
+		Response{
+			Status:           "200 OK",
+			StatusCode:       200,
+			Proto:            "HTTP/1.0",
+			ProtoMajor:       1,
+			ProtoMinor:       0,
+			Request:          dummyReq("HEAD"),
+			Header:           Header{"Content-Length": {"256"}},
+			TransferEncoding: nil,
+			Close:            true,
+			ContentLength:    256,
+		},
+
+		"",
+	},
+
+	// Content-Length in response to a HEAD request with HTTP/1.1
+	{
+		"HTTP/1.1 200 OK\r\n" +
+			"Content-Length: 256\r\n" +
+			"\r\n",
+
+		Response{
+			Status:           "200 OK",
+			StatusCode:       200,
+			Proto:            "HTTP/1.1",
+			ProtoMajor:       1,
+			ProtoMinor:       1,
+			Request:          dummyReq("HEAD"),
+			Header:           Header{"Content-Length": {"256"}},
+			TransferEncoding: nil,
+			Close:            false,
+			ContentLength:    256,
+		},
+
+		"",
+	},
+
+	// No Content-Length or Chunked in response to a HEAD request
+	{
+		"HTTP/1.0 200 OK\r\n" +
+			"\r\n",
+
+		Response{
+			Status:           "200 OK",
+			StatusCode:       200,
+			Proto:            "HTTP/1.0",
+			ProtoMajor:       1,
+			ProtoMinor:       0,
+			Request:          dummyReq("HEAD"),
+			Header:           Header{},
+			TransferEncoding: nil,
+			Close:            true,
+			ContentLength:    -1,
 		},
 
 		"",
diff --git a/libgo/go/net/http/responsewrite_test.go b/libgo/go/net/http/responsewrite_test.go
index f8e63acf4f7..5c10e2161cf 100644
--- a/libgo/go/net/http/responsewrite_test.go
+++ b/libgo/go/net/http/responsewrite_test.go
@@ -15,83 +15,83 @@ type respWriteTest struct {
 	Raw  string
 }
 
-var respWriteTests = []respWriteTest{
-	// HTTP/1.0, identity coding; no trailer
-	{
-		Response{
-			StatusCode:    503,
-			ProtoMajor:    1,
-			ProtoMinor:    0,
-			Request:       dummyReq("GET"),
-			Header:        Header{},
-			Body:          ioutil.NopCloser(bytes.NewBufferString("abcdef")),
-			ContentLength: 6,
-		},
+func TestResponseWrite(t *testing.T) {
+	respWriteTests := []respWriteTest{
+		// HTTP/1.0, identity coding; no trailer
+		{
+			Response{
+				StatusCode:    503,
+				ProtoMajor:    1,
+				ProtoMinor:    0,
+				Request:       dummyReq("GET"),
+				Header:        Header{},
+				Body:          ioutil.NopCloser(bytes.NewBufferString("abcdef")),
+				ContentLength: 6,
+			},
 
-		"HTTP/1.0 503 Service Unavailable\r\n" +
-			"Content-Length: 6\r\n\r\n" +
-			"abcdef",
-	},
-	// Unchunked response without Content-Length.
-	{
-		Response{
-			StatusCode:    200,
-			ProtoMajor:    1,
-			ProtoMinor:    0,
-			Request:       dummyReq("GET"),
-			Header:        Header{},
-			Body:          ioutil.NopCloser(bytes.NewBufferString("abcdef")),
-			ContentLength: -1,
+			"HTTP/1.0 503 Service Unavailable\r\n" +
+				"Content-Length: 6\r\n\r\n" +
+				"abcdef",
 		},
-		"HTTP/1.0 200 OK\r\n" +
-			"\r\n" +
-			"abcdef",
-	},
-	// HTTP/1.1, chunked coding; empty trailer; close
-	{
-		Response{
-			StatusCode:       200,
-			ProtoMajor:       1,
-			ProtoMinor:       1,
-			Request:          dummyReq("GET"),
-			Header:           Header{},
-			Body:             ioutil.NopCloser(bytes.NewBufferString("abcdef")),
-			ContentLength:    6,
-			TransferEncoding: []string{"chunked"},
-			Close:            true,
+		// Unchunked response without Content-Length.
+		{
+			Response{
+				StatusCode:    200,
+				ProtoMajor:    1,
+				ProtoMinor:    0,
+				Request:       dummyReq("GET"),
+				Header:        Header{},
+				Body:          ioutil.NopCloser(bytes.NewBufferString("abcdef")),
+				ContentLength: -1,
+			},
+			"HTTP/1.0 200 OK\r\n" +
+				"\r\n" +
+				"abcdef",
 		},
+		// HTTP/1.1, chunked coding; empty trailer; close
+		{
+			Response{
+				StatusCode:       200,
+				ProtoMajor:       1,
+				ProtoMinor:       1,
+				Request:          dummyReq("GET"),
+				Header:           Header{},
+				Body:             ioutil.NopCloser(bytes.NewBufferString("abcdef")),
+				ContentLength:    6,
+				TransferEncoding: []string{"chunked"},
+				Close:            true,
+			},
 
-		"HTTP/1.1 200 OK\r\n" +
-			"Connection: close\r\n" +
-			"Transfer-Encoding: chunked\r\n\r\n" +
-			"6\r\nabcdef\r\n0\r\n\r\n",
-	},
+			"HTTP/1.1 200 OK\r\n" +
+				"Connection: close\r\n" +
+				"Transfer-Encoding: chunked\r\n\r\n" +
+				"6\r\nabcdef\r\n0\r\n\r\n",
+		},
 
-	// Header value with a newline character (Issue 914).
-	// Also tests removal of leading and trailing whitespace.
-	{
-		Response{
-			StatusCode: 204,
-			ProtoMajor: 1,
-			ProtoMinor: 1,
-			Request:    dummyReq("GET"),
-			Header: Header{
-				"Foo": []string{" Bar\nBaz "},
+		// Header value with a newline character (Issue 914).
+		// Also tests removal of leading and trailing whitespace.
+		{
+			Response{
+				StatusCode: 204,
+				ProtoMajor: 1,
+				ProtoMinor: 1,
+				Request:    dummyReq("GET"),
+				Header: Header{
+					"Foo": []string{" Bar\nBaz "},
+				},
+				Body:             nil,
+				ContentLength:    0,
+				TransferEncoding: []string{"chunked"},
+				Close:            true,
 			},
-			Body:             nil,
-			ContentLength:    0,
-			TransferEncoding: []string{"chunked"},
-			Close:            true,
-		},
 
-		"HTTP/1.1 204 No Content\r\n" +
-			"Connection: close\r\n" +
-			"Foo: Bar Baz\r\n" +
-			"\r\n",
-	},
-}
+			"HTTP/1.1 204 No Content\r\n" +
+				"Connection: close\r\n" +
+				"Foo: Bar Baz\r\n" +
+				"\r\n",
+		},
+	}
 
-func TestResponseWrite(t *testing.T) {
 	for i := range respWriteTests {
 		tt := &respWriteTests[i]
 		var braw bytes.Buffer
diff --git a/libgo/go/net/http/serve_test.go b/libgo/go/net/http/serve_test.go
index 1de4171239d..886ed4e8f74 100644
--- a/libgo/go/net/http/serve_test.go
+++ b/libgo/go/net/http/serve_test.go
@@ -67,6 +67,7 @@ func (a dummyAddr) String() string {
 type testConn struct {
 	readBuf  bytes.Buffer
 	writeBuf bytes.Buffer
+	closec   chan bool // if non-nil, send value to it on close
 }
 
 func (c *testConn) Read(b []byte) (int, error) {
@@ -78,6 +79,10 @@ func (c *testConn) Write(b []byte) (int, error) {
 }
 
 func (c *testConn) Close() error {
+	select {
+	case c.closec <- true:
+	default:
+	}
 	return nil
 }
 
@@ -179,10 +184,11 @@ var vtests = []struct {
 }
 
 func TestHostHandlers(t *testing.T) {
+	mux := NewServeMux()
 	for _, h := range handlers {
-		Handle(h.pattern, stringHandler(h.msg))
+		mux.Handle(h.pattern, stringHandler(h.msg))
 	}
-	ts := httptest.NewServer(nil)
+	ts := httptest.NewServer(mux)
 	defer ts.Close()
 
 	conn, err := net.Dial("tcp", ts.Listener.Addr().String())
@@ -484,6 +490,7 @@ func TestChunkedResponseHeaders(t *testing.T) {
 
 	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
 		w.Header().Set("Content-Length", "intentional gibberish") // we check that this is deleted
+		w.(Flusher).Flush()
 		fmt.Fprintf(w, "I am a chunked response.")
 	}))
 	defer ts.Close()
@@ -764,6 +771,7 @@ func TestServerUnreadRequestBodyLittle(t *testing.T) {
 			t.Errorf("on request, read buffer length is %d; expected about 100 KB", conn.readBuf.Len())
 		}
 		rw.WriteHeader(200)
+		rw.(Flusher).Flush()
 		if g, e := conn.readBuf.Len(), 0; g != e {
 			t.Errorf("after WriteHeader, read buffer length is %d; want %d", g, e)
 		}
@@ -786,24 +794,24 @@ func TestServerUnreadRequestBodyLarge(t *testing.T) {
 			"Content-Length: %d\r\n"+
 			"\r\n", len(body))))
 	conn.readBuf.Write([]byte(body))
-
-	done := make(chan bool)
+	conn.closec = make(chan bool, 1)
 
 	ls := &oneConnListener{conn}
 	go Serve(ls, HandlerFunc(func(rw ResponseWriter, req *Request) {
-		defer close(done)
 		if conn.readBuf.Len() < len(body)/2 {
 			t.Errorf("on request, read buffer length is %d; expected about 1MB", conn.readBuf.Len())
 		}
 		rw.WriteHeader(200)
+		rw.(Flusher).Flush()
 		if conn.readBuf.Len() < len(body)/2 {
 			t.Errorf("post-WriteHeader, read buffer length is %d; expected about 1MB", conn.readBuf.Len())
 		}
-		if c := rw.Header().Get("Connection"); c != "close" {
-			t.Errorf(`Connection header = %q; want "close"`, c)
-		}
 	}))
-	<-done
+	<-conn.closec
+
+	if res := conn.writeBuf.String(); !strings.Contains(res, "Connection: close") {
+		t.Errorf("Expected a Connection: close header; got response: %s", res)
+	}
 }
 
 func TestTimeoutHandler(t *testing.T) {
@@ -1144,22 +1152,17 @@ func TestClientWriteShutdown(t *testing.T) {
 // Tests that chunked server responses that write 1 byte at a time are
 // buffered before chunk headers are added, not after chunk headers.
 func TestServerBufferedChunking(t *testing.T) {
-	if true {
-		t.Logf("Skipping known broken test; see Issue 2357")
-		return
-	}
 	conn := new(testConn)
 	conn.readBuf.Write([]byte("GET / HTTP/1.1\r\n\r\n"))
-	done := make(chan bool)
+	conn.closec = make(chan bool, 1)
 	ls := &oneConnListener{conn}
 	go Serve(ls, HandlerFunc(func(rw ResponseWriter, req *Request) {
-		defer close(done)
-		rw.Header().Set("Content-Type", "text/plain") // prevent sniffing, which buffers
+		rw.(Flusher).Flush() // force the Header to be sent, in chunking mode, not counting the length
 		rw.Write([]byte{'x'})
 		rw.Write([]byte{'y'})
 		rw.Write([]byte{'z'})
 	}))
-	<-done
+	<-conn.closec
 	if !bytes.HasSuffix(conn.writeBuf.Bytes(), []byte("\r\n\r\n3\r\nxyz\r\n0\r\n\r\n")) {
 		t.Errorf("response didn't end with a single 3 byte 'xyz' chunk; got:\n%q",
 			conn.writeBuf.Bytes())
diff --git a/libgo/go/net/http/server.go b/libgo/go/net/http/server.go
index 89a46f06bb2..434943d49a3 100644
--- a/libgo/go/net/http/server.go
+++ b/libgo/go/net/http/server.go
@@ -113,7 +113,6 @@ type conn struct {
 	lr         *io.LimitedReader    // io.LimitReader(sr)
 	buf        *bufio.ReadWriter    // buffered(lr,rwc), reading from bufio->limitReader->sr->rwc
 	tlsState   *tls.ConnectionState // or nil when not using TLS
-	body       []byte
 
 	mu           sync.Mutex // guards the following
 	clientGone   bool       // if client has disconnected mid-request
@@ -193,18 +192,85 @@ func (sr *switchReader) Read(p []byte) (n int, err error) {
 	return r.Read(p)
 }
 
+// This should be >= 512 bytes for DetectContentType,
+// but otherwise it's somewhat arbitrary.
+const bufferBeforeChunkingSize = 2048
+
+// chunkWriter writes to a response's conn buffer, and is the writer
+// wrapped by the response.bufw buffered writer.
+//
+// chunkWriter also is responsible for finalizing the Header, including
+// conditionally setting the Content-Type and setting a Content-Length
+// in cases where the handler's final output is smaller than the buffer
+// size. It also conditionally adds chunk headers, when in chunking mode.
+//
+// See the comment above (*response).Write for the entire write flow.
+type chunkWriter struct {
+	res         *response
+	header      Header // a deep copy of r.Header, once WriteHeader is called
+	wroteHeader bool   // whether the header's been sent
+
+	// set by the writeHeader method:
+	chunking bool // using chunked transfer encoding for reply body
+}
+
+var crlf = []byte("\r\n")
+
+func (cw *chunkWriter) Write(p []byte) (n int, err error) {
+	if !cw.wroteHeader {
+		cw.writeHeader(p)
+	}
+	if cw.chunking {
+		_, err = fmt.Fprintf(cw.res.conn.buf, "%x\r\n", len(p))
+		if err != nil {
+			return
+		}
+	}
+	n, err = cw.res.conn.buf.Write(p)
+	if cw.chunking && err == nil {
+		_, err = cw.res.conn.buf.Write(crlf)
+	}
+	return
+}
+
+func (cw *chunkWriter) flush() {
+	if !cw.wroteHeader {
+		cw.writeHeader(nil)
+	}
+	cw.res.conn.buf.Flush()
+}
+
+func (cw *chunkWriter) close() {
+	if !cw.wroteHeader {
+		cw.writeHeader(nil)
+	}
+	if cw.chunking {
+		// zero EOF chunk, trailer key/value pairs (currently
+		// unsupported in Go's server), followed by a blank
+		// line.
+		io.WriteString(cw.res.conn.buf, "0\r\n\r\n")
+	}
+}
+
 // A response represents the server side of an HTTP response.
 type response struct {
 	conn          *conn
 	req           *Request // request for this response
-	chunking      bool     // using chunked transfer encoding for reply body
-	wroteHeader   bool     // reply header has been written
+	wroteHeader   bool     // reply header has been (logically) written
 	wroteContinue bool     // 100 Continue response was written
-	header        Header   // reply header parameters
-	written       int64    // number of bytes written in body
-	contentLength int64    // explicitly-declared Content-Length; or -1
-	status        int      // status code passed to WriteHeader
-	needSniff     bool     // need to sniff to find Content-Type
+
+	w  *bufio.Writer // buffers output in chunks to chunkWriter
+	cw *chunkWriter
+
+	// handlerHeader is the Header that Handlers get access to,
+	// which may be retained and mutated even after WriteHeader.
+	// handlerHeader is copied into cw.header at WriteHeader
+	// time, and privately mutated thereafter.
+	handlerHeader Header
+
+	written       int64 // number of bytes written in body
+	contentLength int64 // explicitly-declared Content-Length; or -1
+	status        int   // status code passed to WriteHeader
 
 	// close connection after this reply.  set on request and
 	// updated after response from handler if there's a
@@ -220,6 +286,8 @@ type response struct {
 	// subsequent requests on this connection and stop reading
 	// input from it.
 	requestBodyLimitHit bool
+
+	handlerDone bool // set true when the handler exits
 }
 
 // requestTooLarge is called by maxBytesReader when too much input has
@@ -232,27 +300,46 @@ func (w *response) requestTooLarge() {
 	}
 }
 
+// needsSniff returns whether a Content-Type still needs to be sniffed.
+func (w *response) needsSniff() bool {
+	return !w.cw.wroteHeader && w.handlerHeader.Get("Content-Type") == "" && w.written < sniffLen
+}
+
 type writerOnly struct {
 	io.Writer
 }
 
 func (w *response) ReadFrom(src io.Reader) (n int64, err error) {
-	// Call WriteHeader before checking w.chunking if it hasn't
-	// been called yet, since WriteHeader is what sets w.chunking.
 	if !w.wroteHeader {
 		w.WriteHeader(StatusOK)
 	}
-	if !w.chunking && w.bodyAllowed() && !w.needSniff {
-		w.Flush()
+
+	if w.needsSniff() {
+		n0, err := io.Copy(writerOnly{w}, io.LimitReader(src, sniffLen))
+		n += n0
+		if err != nil {
+			return n, err
+		}
+	}
+
+	w.w.Flush()  // get rid of any previous writes
+	w.cw.flush() // make sure Header is written; flush data to rwc
+
+	// Now that cw has been flushed, its chunking field is guaranteed initialized.
+	if !w.cw.chunking && w.bodyAllowed() {
 		if rf, ok := w.conn.rwc.(io.ReaderFrom); ok {
-			n, err = rf.ReadFrom(src)
-			w.written += n
-			return
+			n0, err := rf.ReadFrom(src)
+			n += n0
+			w.written += n0
+			return n, err
 		}
 	}
+
 	// Fall back to default io.Copy implementation.
 	// Use wrapper to hide w.ReadFrom from io.Copy.
-	return io.Copy(writerOnly{w}, src)
+	n0, err := io.Copy(writerOnly{w}, src)
+	n += n0
+	return n, err
 }
 
 // noLimit is an effective infinite upper bound for io.LimitedReader
@@ -272,7 +359,6 @@ func (srv *Server) newConn(rwc net.Conn) (c *conn, err error) {
 		c.rwc = newLoggingConn("server", c.rwc)
 	}
 	c.sr = switchReader{r: c.rwc}
-	c.body = make([]byte, sniffLen)
 	c.lr = io.LimitReader(&c.sr, noLimit).(*io.LimitedReader)
 	br := bufio.NewReader(c.lr)
 	bw := bufio.NewWriter(c.rwc)
@@ -343,17 +429,20 @@ func (c *conn) readRequest() (w *response, err error) {
 	req.RemoteAddr = c.remoteAddr
 	req.TLS = c.tlsState
 
-	w = new(response)
-	w.conn = c
-	w.req = req
-	w.header = make(Header)
-	w.contentLength = -1
-	c.body = c.body[:0]
+	w = &response{
+		conn:          c,
+		req:           req,
+		handlerHeader: make(Header),
+		contentLength: -1,
+		cw:            new(chunkWriter),
+	}
+	w.cw.res = w
+	w.w = bufio.NewWriterSize(w.cw, bufferBeforeChunkingSize)
 	return w, nil
 }
 
 func (w *response) Header() Header {
-	return w.header
+	return w.handlerHeader
 }
 
 // maxPostHandlerReadBytes is the max number of Request.Body bytes not
@@ -379,30 +468,68 @@ func (w *response) WriteHeader(code int) {
 	w.wroteHeader = true
 	w.status = code
 
-	// Check for a explicit (and valid) Content-Length header.
-	var hasCL bool
-	var contentLength int64
-	if clenStr := w.header.get("Content-Length"); clenStr != "" {
-		var err error
-		contentLength, err = strconv.ParseInt(clenStr, 10, 64)
-		if err == nil {
-			hasCL = true
+	w.cw.header = w.handlerHeader.clone()
+
+	if cl := w.cw.header.get("Content-Length"); cl != "" {
+		v, err := strconv.ParseInt(cl, 10, 64)
+		if err == nil && v >= 0 {
+			w.contentLength = v
 		} else {
-			log.Printf("http: invalid Content-Length of %q sent", clenStr)
-			w.header.Del("Content-Length")
+			log.Printf("http: invalid Content-Length of %q", cl)
+			w.cw.header.Del("Content-Length")
+		}
+	}
+}
+
+// writeHeader finalizes the header sent to the client and writes it
+// to cw.res.conn.buf.
+//
+// p is not written by writeHeader, but is the first chunk of the body
+// that will be written.  It is sniffed for a Content-Type if none is
+// set explicitly.  It's also used to set the Content-Length, if the
+// total body size was small and the handler has already finished
+// running.
+func (cw *chunkWriter) writeHeader(p []byte) {
+	if cw.wroteHeader {
+		return
+	}
+	cw.wroteHeader = true
+
+	w := cw.res
+	code := w.status
+	done := w.handlerDone
+
+	// If the handler is done but never sent a Content-Length
+	// response header and this is our first (and last) write, set
+	// it, even to zero. This helps HTTP/1.0 clients keep their
+	// "keep-alive" connections alive.
+	if done && cw.header.get("Content-Length") == "" && w.req.Method != "HEAD" {
+		w.contentLength = int64(len(p))
+		cw.header.Set("Content-Length", strconv.Itoa(len(p)))
+	}
+
+	// If this was an HTTP/1.0 request with keep-alive and we sent a
+	// Content-Length back, we can make this a keep-alive response ...
+	if w.req.wantsHttp10KeepAlive() {
+		sentLength := cw.header.get("Content-Length") != ""
+		if sentLength && cw.header.get("Connection") == "keep-alive" {
+			w.closeAfterReply = false
 		}
 	}
 
+	// Check for a explicit (and valid) Content-Length header.
+	hasCL := w.contentLength != -1
+
 	if w.req.wantsHttp10KeepAlive() && (w.req.Method == "HEAD" || hasCL) {
-		_, connectionHeaderSet := w.header["Connection"]
+		_, connectionHeaderSet := cw.header["Connection"]
 		if !connectionHeaderSet {
-			w.header.Set("Connection", "keep-alive")
+			cw.header.Set("Connection", "keep-alive")
 		}
 	} else if !w.req.ProtoAtLeast(1, 1) || w.req.wantsClose() {
 		w.closeAfterReply = true
 	}
 
-	if w.header.get("Connection") == "close" {
+	if cw.header.get("Connection") == "close" {
 		w.closeAfterReply = true
 	}
 
@@ -416,7 +543,7 @@ func (w *response) WriteHeader(code int) {
 			n, _ := io.CopyN(ioutil.Discard, w.req.Body, maxPostHandlerReadBytes+1)
 			if n >= maxPostHandlerReadBytes {
 				w.requestTooLarge()
-				w.header.Set("Connection", "close")
+				cw.header.Set("Connection", "close")
 			} else {
 				w.req.Body.Close()
 			}
@@ -426,69 +553,65 @@ func (w *response) WriteHeader(code int) {
 	if code == StatusNotModified {
 		// Must not have body.
 		for _, header := range []string{"Content-Type", "Content-Length", "Transfer-Encoding"} {
-			if w.header.get(header) != "" {
-				// TODO: return an error if WriteHeader gets a return parameter
-				// or set a flag on w to make future Writes() write an error page?
-				// for now just log and drop the header.
-				log.Printf("http: StatusNotModified response with header %q defined", header)
-				w.header.Del(header)
+			// RFC 2616 section 10.3.5: "the response MUST NOT include other entity-headers"
+			if cw.header.get(header) != "" {
+				cw.header.Del(header)
 			}
 		}
 	} else {
 		// If no content type, apply sniffing algorithm to body.
-		if w.header.get("Content-Type") == "" && w.req.Method != "HEAD" {
-			w.needSniff = true
+		if cw.header.get("Content-Type") == "" && w.req.Method != "HEAD" {
+			cw.header.Set("Content-Type", DetectContentType(p))
 		}
 	}
 
-	if _, ok := w.header["Date"]; !ok {
-		w.Header().Set("Date", time.Now().UTC().Format(TimeFormat))
+	if _, ok := cw.header["Date"]; !ok {
+		cw.header.Set("Date", time.Now().UTC().Format(TimeFormat))
 	}
 
-	te := w.header.get("Transfer-Encoding")
+	te := cw.header.get("Transfer-Encoding")
 	hasTE := te != ""
 	if hasCL && hasTE && te != "identity" {
 		// TODO: return an error if WriteHeader gets a return parameter
 		// For now just ignore the Content-Length.
 		log.Printf("http: WriteHeader called with both Transfer-Encoding of %q and a Content-Length of %d",
-			te, contentLength)
-		w.header.Del("Content-Length")
+			te, w.contentLength)
+		cw.header.Del("Content-Length")
 		hasCL = false
 	}
 
 	if w.req.Method == "HEAD" || code == StatusNotModified {
 		// do nothing
 	} else if code == StatusNoContent {
-		w.header.Del("Transfer-Encoding")
+		cw.header.Del("Transfer-Encoding")
 	} else if hasCL {
-		w.contentLength = contentLength
-		w.header.Del("Transfer-Encoding")
+		cw.header.Del("Transfer-Encoding")
 	} else if w.req.ProtoAtLeast(1, 1) {
 		// HTTP/1.1 or greater: use chunked transfer encoding
 		// to avoid closing the connection at EOF.
 		// TODO: this blows away any custom or stacked Transfer-Encoding they
 		// might have set.  Deal with that as need arises once we have a valid
 		// use case.
-		w.chunking = true
-		w.header.Set("Transfer-Encoding", "chunked")
+		cw.chunking = true
+		cw.header.Set("Transfer-Encoding", "chunked")
 	} else {
 		// HTTP version < 1.1: cannot do chunked transfer
 		// encoding and we don't know the Content-Length so
 		// signal EOF by closing connection.
 		w.closeAfterReply = true
-		w.header.Del("Transfer-Encoding") // in case already set
+		cw.header.Del("Transfer-Encoding") // in case already set
 	}
 
 	// Cannot use Content-Length with non-identity Transfer-Encoding.
-	if w.chunking {
-		w.header.Del("Content-Length")
+	if cw.chunking {
+		cw.header.Del("Content-Length")
 	}
 	if !w.req.ProtoAtLeast(1, 0) {
 		return
 	}
 
-	if w.closeAfterReply && !hasToken(w.header.get("Connection"), "close") {
-		w.header.Set("Connection", "close")
+	if w.closeAfterReply && !hasToken(cw.header.get("Connection"), "close") {
+		cw.header.Set("Connection", "close")
 	}
 
 	proto := "HTTP/1.0"
@@ -501,37 +624,8 @@ func (w *response) WriteHeader(code int) {
 		text = "status code " + codestring
 	}
 	io.WriteString(w.conn.buf, proto+" "+codestring+" "+text+"\r\n")
-	w.header.Write(w.conn.buf)
-
-	// If we need to sniff the body, leave the header open.
-	// Otherwise, end it here.
-	if !w.needSniff {
-		io.WriteString(w.conn.buf, "\r\n")
-	}
-}
-
-// sniff uses the first block of written data,
-// stored in w.conn.body, to decide the Content-Type
-// for the HTTP body.
-func (w *response) sniff() {
-	if !w.needSniff {
-		return
-	}
-	w.needSniff = false
-
-	data := w.conn.body
-	fmt.Fprintf(w.conn.buf, "Content-Type: %s\r\n\r\n", DetectContentType(data))
-
-	if len(data) == 0 {
-		return
-	}
-	if w.chunking {
-		fmt.Fprintf(w.conn.buf, "%x\r\n", len(data))
-	}
-	_, err := w.conn.buf.Write(data)
-	if w.chunking && err == nil {
-		io.WriteString(w.conn.buf, "\r\n")
-	}
+	cw.header.Write(w.conn.buf)
+	w.conn.buf.Write(crlf)
 }
 
 // bodyAllowed returns true if a Write is allowed for this response type.
@@ -543,6 +637,38 @@ func (w *response) bodyAllowed() bool {
 	return w.status != StatusNotModified && w.req.Method != "HEAD"
 }
 
+// The Life Of A Write is like this:
+//
+// Handler starts. No header has been sent. The handler can either
+// write a header, or just start writing.  Writing before sending a header
+// sends an implicity empty 200 OK header.
+//
+// If the handler didn't declare a Content-Length up front, we either
+// go into chunking mode or, if the handler finishes running before
+// the chunking buffer size, we compute a Content-Length and send that
+// in the header instead.
+//
+// Likewise, if the handler didn't set a Content-Type, we sniff that
+// from the initial chunk of output.
+//
+// The Writers are wired together like:
+//
+// 1. *response (the ResponseWriter) ->
+// 2. (*response).w, a *bufio.Writer of bufferBeforeChunkingSize bytes
+// 3. chunkWriter.Writer (whose writeHeader finalizes Content-Length/Type)
+//    and which writes the chunk headers, if needed.
+// 4. conn.buf, a bufio.Writer of default (4kB) bytes
+// 5. the rwc, the net.Conn.
+//
+// TODO(bradfitz): short-circuit some of the buffering when the
+// initial header contains both a Content-Type and Content-Length.
+// Also short-circuit in (1) when the header's been sent and not in
+// chunking mode, writing directly to (4) instead, if (2) has no
+// buffered data.  More generally, we could short-circuit from (1) to
+// (3) even in chunking mode if the write size from (1) is over some
+// threshold and nothing is in (2).  The answer might be mostly making
+// bufferBeforeChunkingSize smaller and having bufio's fast-paths deal
+// with this instead.
 func (w *response) Write(data []byte) (n int, err error) {
 	if w.conn.hijacked() {
 		log.Print("http: response.Write on hijacked connection")
@@ -562,81 +688,20 @@ func (w *response) Write(data []byte) (n int, err error) {
 	if w.contentLength != -1 && w.written > w.contentLength {
 		return 0, ErrContentLength
 	}
-
-	var m int
-	if w.needSniff {
-		// We need to sniff the beginning of the output to
-		// determine the content type.  Accumulate the
-		// initial writes in w.conn.body.
-		// Cap m so that append won't allocate.
-		m = cap(w.conn.body) - len(w.conn.body)
-		if m > len(data) {
-			m = len(data)
-		}
-		w.conn.body = append(w.conn.body, data[:m]...)
-		data = data[m:]
-		if len(data) == 0 {
-			// Copied everything into the buffer.
-			// Wait for next write.
-			return m, nil
-		}
-
-		// Filled the buffer; more data remains.
-		// Sniff the content (flushes the buffer)
-		// and then proceed with the remainder
-		// of the data as a normal Write.
-		// Calling sniff clears needSniff.
-		w.sniff()
-	}
-
-	// TODO(rsc): if chunking happened after the buffering,
-	// then there would be fewer chunk headers.
-	// On the other hand, it would make hijacking more difficult.
-	if w.chunking {
-		fmt.Fprintf(w.conn.buf, "%x\r\n", len(data))
-	}
-	n, err = w.conn.buf.Write(data)
-	if err == nil && w.chunking {
-		if n != len(data) {
-			err = io.ErrShortWrite
-		}
-		if err == nil {
-			io.WriteString(w.conn.buf, "\r\n")
-		}
-	}
-
-	return m + n, err
+	return w.w.Write(data)
 }
 
 func (w *response) finishRequest() {
-	// If the handler never wrote any bytes and never sent a Content-Length
-	// response header, set the length explicitly to zero. This helps
-	// HTTP/1.0 clients keep their "keep-alive" connections alive, and for
-	// HTTP/1.1 clients is just as good as the alternative: sending a
-	// chunked response and immediately sending the zero-length EOF chunk.
-	if w.written == 0 && w.header.get("Content-Length") == "" && w.req.Method != "HEAD" {
-		w.header.Set("Content-Length", "0")
-	}
-	// If this was an HTTP/1.0 request with keep-alive and we sent a
-	// Content-Length back, we can make this a keep-alive response ...
-	if w.req.wantsHttp10KeepAlive() {
-		sentLength := w.header.get("Content-Length") != ""
-		if sentLength && w.header.get("Connection") == "keep-alive" {
-			w.closeAfterReply = false
-		}
-	}
+	w.handlerDone = true
+
 	if !w.wroteHeader {
 		w.WriteHeader(StatusOK)
 	}
-	if w.needSniff {
-		w.sniff()
-	}
-	if w.chunking {
-		io.WriteString(w.conn.buf, "0\r\n")
-		// trailer key/value pairs, followed by blank line
-		io.WriteString(w.conn.buf, "\r\n")
-	}
+
+	w.w.Flush()
+	w.cw.close()
 	w.conn.buf.Flush()
+
 	// Close the body, unless we're about to close the whole TCP connection
 	// anyway.
 	if !w.closeAfterReply {
@@ -646,7 +711,7 @@ func (w *response) finishRequest() {
 		w.req.MultipartForm.RemoveAll()
 	}
 
-	if w.contentLength != -1 && w.contentLength != w.written {
+	if w.contentLength != -1 && w.bodyAllowed() && w.contentLength != w.written {
 		// Did not write enough. Avoid getting out of sync.
 		w.closeAfterReply = true
 	}
@@ -656,8 +721,8 @@ func (w *response) Flush() {
 	if !w.wroteHeader {
 		w.WriteHeader(StatusOK)
 	}
-	w.sniff()
-	w.conn.buf.Flush()
+	w.w.Flush()
+	w.cw.flush()
 }
 
 func (c *conn) finalFlush() {
@@ -809,6 +874,9 @@ func (w *response) sendExpectationFailed() {
 // Hijack implements the Hijacker.Hijack method. Our response is both a ResponseWriter
 // and a Hijacker.
 func (w *response) Hijack() (rwc net.Conn, buf *bufio.ReadWriter, err error) {
+	if w.wroteHeader {
+		w.cw.flush()
+	}
 	return w.conn.hijack()
 }
 
@@ -1148,7 +1216,7 @@ func HandleFunc(pattern string, handler func(ResponseWriter, *Request)) {
 }
 
 // Serve accepts incoming HTTP connections on the listener l,
-// creating a new service thread for each.  The service threads
+// creating a new service goroutine for each.  The service goroutines
 // read requests and then call handler to reply to them.
 // Handler is typically nil, in which case the DefaultServeMux is used.
 func Serve(l net.Listener, handler Handler) error {
@@ -1182,7 +1250,7 @@ func (srv *Server) ListenAndServe() error {
 }
 
 // Serve accepts incoming connections on the Listener l, creating a
-// new service thread for each.  The service threads read requests and
+// new service goroutine for each.  The service goroutines read requests and
 // then call srv.Handler to reply to them.
 func (srv *Server) Serve(l net.Listener) error {
 	defer l.Close()
@@ -1327,7 +1395,7 @@ func (srv *Server) ListenAndServeTLS(certFile, keyFile string) error {
 // TimeoutHandler returns a Handler that runs h with the given time limit.
 //
 // The new Handler calls h.ServeHTTP to handle each request, but if a
-// call runs for more than ns nanoseconds, the handler responds with
+// call runs for longer than its time limit, the handler responds with
 // a 503 Service Unavailable error and the given message in its body.
 // (If msg is empty, a suitable default message will be sent.)
 // After such a timeout, writes by h to its ResponseWriter will return
diff --git a/libgo/go/net/http/transfer.go b/libgo/go/net/http/transfer.go
index 70ea15b8e4a..25b34addec7 100644
--- a/libgo/go/net/http/transfer.go
+++ b/libgo/go/net/http/transfer.go
@@ -87,10 +87,8 @@ func newTransferWriter(r interface{}) (t *transferWriter, err error) {
 	// Sanitize Body,ContentLength,TransferEncoding
 	if t.ResponseToHEAD {
 		t.Body = nil
-		t.TransferEncoding = nil
-		// ContentLength is expected to hold Content-Length
-		if t.ContentLength < 0 {
-			return nil, ErrMissingContentLength
+		if chunked(t.TransferEncoding) {
+			t.ContentLength = -1
 		}
 	} else {
 		if !atLeastHTTP11 || t.Body == nil {
@@ -122,9 +120,6 @@ func (t *transferWriter) shouldSendContentLength() bool {
 	if t.ContentLength > 0 {
 		return true
 	}
-	if t.ResponseToHEAD {
-		return true
-	}
 	// Many servers expect a Content-Length for these methods
 	if t.Method == "POST" || t.Method == "PUT" {
 		return true
@@ -380,12 +375,6 @@ func fixTransferEncoding(requestMethod string, header Header) ([]string, error)
 
 	delete(header, "Transfer-Encoding")
 
-	// Head responses have no bodies, so the transfer encoding
-	// should be ignored.
-	if requestMethod == "HEAD" {
-		return nil, nil
-	}
-
 	encodings := strings.Split(raw[0], ",")
 	te := make([]string, 0, len(encodings))
 	// TODO: Even though we only support "identity" and "chunked"
diff --git a/libgo/go/net/http/transport.go b/libgo/go/net/http/transport.go
index d0505bf13f0..98e198e78af 100644
--- a/libgo/go/net/http/transport.go
+++ b/libgo/go/net/http/transport.go
@@ -450,7 +450,15 @@ func useProxy(addr string) bool {
 		if hasPort(p) {
 			p = p[:strings.LastIndex(p, ":")]
 		}
-		if addr == p || (p[0] == '.' && (strings.HasSuffix(addr, p) || addr == p[1:])) {
+		if addr == p {
+			return false
+		}
+		if p[0] == '.' && (strings.HasSuffix(addr, p) || addr == p[1:]) {
+			// no_proxy ".foo.com" matches "bar.foo.com" or "foo.com"
+			return false
+		}
+		if p[0] != '.' && strings.HasSuffix(addr, p) && addr[len(addr)-len(p)-1] == '.' {
+			// no_proxy "foo.com" matches "bar.foo.com"
 			return false
 		}
 	}
diff --git a/libgo/go/net/http/transport_test.go b/libgo/go/net/http/transport_test.go
index c37ef13a416..daaecae341b 100644
--- a/libgo/go/net/http/transport_test.go
+++ b/libgo/go/net/http/transport_test.go
@@ -390,8 +390,7 @@ func TestTransportServerClosingUnexpectedly(t *testing.T) {
 // This fails pretty reliably with GOMAXPROCS=100 or something high.
 func TestStressSurpriseServerCloses(t *testing.T) {
 	if testing.Short() {
-		t.Logf("skipping test in short mode")
-		return
+		t.Skip("skipping test in short mode")
 	}
 	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
 		w.Header().Set("Content-Length", "5")
@@ -1115,18 +1114,43 @@ func TestTransportNoHost(t *testing.T) {
 	}
 }
 
-var proxyFromEnvTests = []struct {
+type proxyFromEnvTest struct {
+	req     string // URL to fetch; blank means "http://example.com"
 	env     string
-	wanturl string
+	noenv   string
+	want    string
 	wanterr error
-}{
-	{"127.0.0.1:8080", "http://127.0.0.1:8080", nil},
-	{"cache.corp.example.com:1234", "http://cache.corp.example.com:1234", nil},
-	{"cache.corp.example.com", "http://cache.corp.example.com", nil},
-	{"https://cache.corp.example.com", "https://cache.corp.example.com", nil},
-	{"http://127.0.0.1:8080", "http://127.0.0.1:8080", nil},
-	{"https://127.0.0.1:8080", "https://127.0.0.1:8080", nil},
-	{"", "<nil>", nil},
+}
+
+func (t proxyFromEnvTest) String() string {
+	var buf bytes.Buffer
+	if t.env != "" {
+		fmt.Fprintf(&buf, "http_proxy=%q", t.env)
+	}
+	if t.noenv != "" {
+		fmt.Fprintf(&buf, " no_proxy=%q", t.noenv)
+	}
+	req := "http://example.com"
+	if t.req != "" {
+		req = t.req
+	}
+	fmt.Fprintf(&buf, " req=%q", req)
+	return strings.TrimSpace(buf.String())
+}
+
+var proxyFromEnvTests = []proxyFromEnvTest{
+	{env: "127.0.0.1:8080", want: "http://127.0.0.1:8080"},
+	{env: "cache.corp.example.com:1234", want: "http://cache.corp.example.com:1234"},
+	{env: "cache.corp.example.com", want: "http://cache.corp.example.com"},
+	{env: "https://cache.corp.example.com", want: "https://cache.corp.example.com"},
+	{env: "http://127.0.0.1:8080", want: "http://127.0.0.1:8080"},
+	{env: "https://127.0.0.1:8080", want: "https://127.0.0.1:8080"},
+	{want: "<nil>"},
+	{noenv: "example.com", req: "http://example.com/", env: "proxy", want: "<nil>"},
+	{noenv: ".example.com", req: "http://example.com/", env: "proxy", want: "<nil>"},
+	{noenv: "ample.com", req: "http://example.com/", env: "proxy", want: "http://proxy"},
+	{noenv: "example.com", req: "http://foo.example.com/", env: "proxy", want: "<nil>"},
+	{noenv: ".foo.com", req: "http://example.com/", env: "proxy", want: "http://proxy"},
 }
 
 func TestProxyFromEnvironment(t *testing.T) {
@@ -1134,16 +1158,21 @@ func TestProxyFromEnvironment(t *testing.T) {
 	os.Setenv("http_proxy", "")
 	os.Setenv("NO_PROXY", "")
 	os.Setenv("no_proxy", "")
-	for i, tt := range proxyFromEnvTests {
+	for _, tt := range proxyFromEnvTests {
 		os.Setenv("HTTP_PROXY", tt.env)
-		req, _ := NewRequest("GET", "http://example.com", nil)
+		os.Setenv("NO_PROXY", tt.noenv)
+		reqURL := tt.req
+		if reqURL == "" {
+			reqURL = "http://example.com"
+		}
+		req, _ := NewRequest("GET", reqURL, nil)
 		url, err := ProxyFromEnvironment(req)
 		if g, e := fmt.Sprintf("%v", err), fmt.Sprintf("%v", tt.wanterr); g != e {
-			t.Errorf("%d. got error = %q, want %q", i, g, e)
+			t.Errorf("%v: got error = %q, want %q", tt, g, e)
 			continue
 		}
-		if got := fmt.Sprintf("%s", url); got != tt.wanturl {
-			t.Errorf("%d. got URL = %q, want %q", i, url, tt.wanturl)
+		if got := fmt.Sprintf("%s", url); got != tt.want {
+			t.Errorf("%v: got URL = %q, want %q", tt, url, tt.want)
 		}
 	}
 }
diff --git a/libgo/go/net/interface_bsd.go b/libgo/go/net/interface_bsd.go
index 7f090d8d406..df9b3a2f279 100644
--- a/libgo/go/net/interface_bsd.go
+++ b/libgo/go/net/interface_bsd.go
@@ -118,7 +118,9 @@ func interfaceAddrTable(ifindex int) ([]Addr, error) {
 				if err != nil {
 					return nil, err
 				}
-				ifat = append(ifat, ifa)
+				if ifa != nil {
+					ifat = append(ifat, ifa)
+				}
 			}
 		}
 	}
@@ -157,6 +159,8 @@ func newAddr(m *syscall.InterfaceAddrMessage) (Addr, error) {
 					ifa.IP[2], ifa.IP[3] = 0, 0
 				}
 			}
+		default: // Sockaddrs contain syscall.SockaddrDatalink on NetBSD
+			return nil, nil
 		}
 	}
 	return ifa, nil
diff --git a/libgo/go/net/interface_test.go b/libgo/go/net/interface_test.go
index 2fe0f60caea..803c1f4495c 100644
--- a/libgo/go/net/interface_test.go
+++ b/libgo/go/net/interface_test.go
@@ -75,9 +75,13 @@ func testInterfaceMulticastAddrs(t *testing.T, ifi *Interface) {
 
 func testAddrs(t *testing.T, ifat []Addr) {
 	for _, ifa := range ifat {
-		switch ifa.(type) {
+		switch v := ifa.(type) {
 		case *IPAddr, *IPNet:
-			t.Logf("\tinterface address %q", ifa.String())
+			if v == nil {
+				t.Errorf("\tunexpected value: %v", ifa)
+			} else {
+				t.Logf("\tinterface address %q", ifa.String())
+			}
 		default:
 			t.Errorf("\tunexpected type: %T", ifa)
 		}
@@ -86,9 +90,13 @@ func testAddrs(t *testing.T, ifat []Addr) {
 
 func testMulticastAddrs(t *testing.T, ifmat []Addr) {
 	for _, ifma := range ifmat {
-		switch ifma.(type) {
+		switch v := ifma.(type) {
 		case *IPAddr:
-			t.Logf("\tjoined group address %q", ifma.String())
+			if v == nil {
+				t.Errorf("\tunexpected value: %v", ifma)
+			} else {
+				t.Logf("\tjoined group address %q", ifma.String())
+			}
 		default:
 			t.Errorf("\tunexpected type: %T", ifma)
 		}
diff --git a/libgo/go/net/ip.go b/libgo/go/net/ip.go
index 0aac3d187a1..d588e3a4294 100644
--- a/libgo/go/net/ip.go
+++ b/libgo/go/net/ip.go
@@ -7,7 +7,7 @@
 // IPv4 addresses are 4 bytes; IPv6 addresses are 16 bytes.
 // An IPv4 address can be converted to an IPv6 address by
 // adding a canonical prefix (10 zeros, 2 0xFFs).
-// This library accepts either size of byte array but always
+// This library accepts either size of byte slice but always
 // returns 16-byte addresses.
 
 package net
@@ -18,14 +18,14 @@ const (
 	IPv6len = 16
 )
 
-// An IP is a single IP address, an array of bytes.
+// An IP is a single IP address, a slice of bytes.
 // Functions in this package accept either 4-byte (IPv4)
-// or 16-byte (IPv6) arrays as input.
+// or 16-byte (IPv6) slices as input.
 //
 // Note that in this documentation, referring to an
 // IP address as an IPv4 address or an IPv6 address
 // is a semantic property of the address, not just the
-// length of the byte array: a 16-byte array can still
+// length of the byte slice: a 16-byte slice can still
 // be an IPv4 address.
 type IP []byte
 
diff --git a/libgo/go/net/ipraw_test.go b/libgo/go/net/ipraw_test.go
index f21889fcbea..db1c7694bb0 100644
--- a/libgo/go/net/ipraw_test.go
+++ b/libgo/go/net/ipraw_test.go
@@ -61,8 +61,7 @@ var icmpTests = []struct {
 
 func TestICMP(t *testing.T) {
 	if os.Getuid() != 0 {
-		t.Logf("skipping test; must be root")
-		return
+		t.Skip("skipping test; must be root")
 	}
 
 	seqnum := 61455
@@ -253,8 +252,7 @@ var ipConnLocalNameTests = []struct {
 
 func TestIPConnLocalName(t *testing.T) {
 	if os.Getuid() != 0 {
-		t.Logf("skipping test; must be root")
-		return
+		t.Skip("skipping test; must be root")
 	}
 
 	for _, tt := range ipConnLocalNameTests {
diff --git a/libgo/go/net/lookup_test.go b/libgo/go/net/lookup_test.go
index 990ade9e210..3355e469489 100644
--- a/libgo/go/net/lookup_test.go
+++ b/libgo/go/net/lookup_test.go
@@ -17,8 +17,7 @@ var testExternal = flag.Bool("external", true, "allow use of external networks d
 
 func TestGoogleSRV(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	_, addrs, err := LookupSRV("xmpp-server", "tcp", "google.com")
 	if err != nil {
@@ -40,8 +39,7 @@ func TestGoogleSRV(t *testing.T) {
 
 func TestGmailMX(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	mx, err := LookupMX("gmail.com")
 	if err != nil {
@@ -54,8 +52,7 @@ func TestGmailMX(t *testing.T) {
 
 func TestGmailNS(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	ns, err := LookupNS("gmail.com")
 	if err != nil {
@@ -68,8 +65,7 @@ func TestGmailNS(t *testing.T) {
 
 func TestGmailTXT(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	txt, err := LookupTXT("gmail.com")
 	if err != nil {
@@ -82,8 +78,7 @@ func TestGmailTXT(t *testing.T) {
 
 func TestGoogleDNSAddr(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	names, err := LookupAddr("8.8.8.8")
 	if err != nil {
@@ -96,8 +91,7 @@ func TestGoogleDNSAddr(t *testing.T) {
 
 func TestLookupIANACNAME(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 	cname, err := LookupCNAME("www.iana.org")
 	if !strings.HasSuffix(cname, ".icann.org.") || err != nil {
diff --git a/libgo/go/net/multicast_posix_test.go b/libgo/go/net/multicast_posix_test.go
index bcc13ee8511..5850a6be0f7 100644
--- a/libgo/go/net/multicast_posix_test.go
+++ b/libgo/go/net/multicast_posix_test.go
@@ -48,12 +48,10 @@ var multicastListenerTests = []struct {
 func TestMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "netbsd", "openbsd", "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	case "linux":
 		if runtime.GOARCH == "arm" || runtime.GOARCH == "alpha" {
-			t.Logf("skipping test on %q/%q", runtime.GOOS, runtime.GOARCH)
-			return
+			t.Skipf("skipping test on %q/%q", runtime.GOOS, runtime.GOARCH)
 		}
 	}
 
@@ -83,12 +81,10 @@ func TestMulticastListener(t *testing.T) {
 func TestSimpleMulticastListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	case "windows":
 		if testing.Short() || !*testExternal {
-			t.Logf("skipping test on windows to avoid firewall")
-			return
+			t.Skip("skipping test on windows to avoid firewall")
 		}
 	}
 
diff --git a/libgo/go/net/net_test.go b/libgo/go/net/net_test.go
index a4e8dcd4455..8a560b52194 100644
--- a/libgo/go/net/net_test.go
+++ b/libgo/go/net/net_test.go
@@ -15,8 +15,7 @@ import (
 
 func TestShutdown(t *testing.T) {
 	if runtime.GOOS == "plan9" {
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	ln, err := Listen("tcp", "127.0.0.1:0")
 	if err != nil {
@@ -63,8 +62,7 @@ func TestShutdown(t *testing.T) {
 func TestShutdownUnix(t *testing.T) {
 	switch runtime.GOOS {
 	case "windows", "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	f, err := ioutil.TempFile("", "go_net_unixtest")
 	if err != nil {
@@ -145,8 +143,7 @@ func TestTCPListenClose(t *testing.T) {
 func TestUDPListenClose(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	ln, err := ListenPacket("udp", "127.0.0.1:0")
 	if err != nil {
diff --git a/libgo/go/net/parse_test.go b/libgo/go/net/parse_test.go
index 30fda45dfd4..9df0c534b33 100644
--- a/libgo/go/net/parse_test.go
+++ b/libgo/go/net/parse_test.go
@@ -15,8 +15,7 @@ func TestReadLine(t *testing.T) {
 	// /etc/services file does not exist on windows and Plan 9.
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	filename := "/etc/services" // a nice big file
 
diff --git a/libgo/go/net/protoconn_test.go b/libgo/go/net/protoconn_test.go
index d99de3f138c..1344fba8a06 100644
--- a/libgo/go/net/protoconn_test.go
+++ b/libgo/go/net/protoconn_test.go
@@ -156,12 +156,10 @@ func TestUDPConnSpecificMethods(t *testing.T) {
 func TestIPConnSpecificMethods(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping read test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping read test on %q", runtime.GOOS)
 	}
 	if os.Getuid() != 0 {
-		t.Logf("skipping test; must be root")
-		return
+		t.Skipf("skipping test; must be root")
 	}
 
 	la, err := net.ResolveIPAddr("ip4", "127.0.0.1")
@@ -212,8 +210,7 @@ func TestIPConnSpecificMethods(t *testing.T) {
 func TestUnixListenerSpecificMethods(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping read test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping read test on %q", runtime.GOOS)
 	}
 
 	p := "/tmp/gotest.net"
@@ -259,8 +256,7 @@ func TestUnixListenerSpecificMethods(t *testing.T) {
 func TestUnixConnSpecificMethods(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	p1, p2, p3 := "/tmp/gotest.net1", "/tmp/gotest.net2", "/tmp/gotest.net3"
diff --git a/libgo/go/net/server_test.go b/libgo/go/net/server_test.go
index 158b9477d03..eba1e7d9691 100644
--- a/libgo/go/net/server_test.go
+++ b/libgo/go/net/server_test.go
@@ -142,8 +142,7 @@ var seqpacketConnServerTests = []struct {
 
 func TestSeqpacketConnServer(t *testing.T) {
 	if runtime.GOOS != "linux" {
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	for _, tt := range seqpacketConnServerTests {
diff --git a/libgo/go/net/sock_cloexec.go b/libgo/go/net/sock_cloexec.go
new file mode 100644
index 00000000000..e2a5ef7160a
--- /dev/null
+++ b/libgo/go/net/sock_cloexec.go
@@ -0,0 +1,69 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file implements sysSocket and accept for platforms that
+// provide a fast path for setting SetNonblock and CloseOnExec.
+
+// +build linux
+
+package net
+
+import "syscall"
+
+// Wrapper around the socket system call that marks the returned file
+// descriptor as nonblocking and close-on-exec.
+func sysSocket(f, t, p int) (int, error) {
+	s, err := syscall.Socket(f, t|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, p)
+	// The SOCK_NONBLOCK and SOCK_CLOEXEC flags were introduced in
+	// Linux 2.6.27.  If we get an EINVAL error, fall back to
+	// using socket without them.
+	if err == nil || err != syscall.EINVAL {
+		return s, err
+	}
+
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	syscall.ForkLock.RLock()
+	s, err = syscall.Socket(f, t, p)
+	if err == nil {
+		syscall.CloseOnExec(s)
+	}
+	syscall.ForkLock.RUnlock()
+	if err != nil {
+		return -1, err
+	}
+	if err = syscall.SetNonblock(s, true); err != nil {
+		syscall.Close(s)
+		return -1, err
+	}
+	return s, nil
+}
+
+// Wrapper around the accept system call that marks the returned file
+// descriptor as nonblocking and close-on-exec.
+func accept(fd int) (int, syscall.Sockaddr, error) {
+	nfd, sa, err := syscall.Accept4(fd, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
+	// The accept4 system call was introduced in Linux 2.6.28.  If
+	// we get an ENOSYS error, fall back to using accept.
+	if err == nil || err != syscall.ENOSYS {
+		return nfd, sa, err
+	}
+
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	// It is okay to hold the lock across syscall.Accept
+	// because we have put fd.sysfd into non-blocking mode.
+	syscall.ForkLock.RLock()
+	nfd, sa, err = syscall.Accept(fd)
+	if err == nil {
+		syscall.CloseOnExec(nfd)
+	}
+	syscall.ForkLock.RUnlock()
+	if err != nil {
+		return -1, nil, err
+	}
+	if err = syscall.SetNonblock(nfd, true); err != nil {
+		syscall.Close(nfd)
+		return -1, nil, err
+	}
+	return nfd, sa, nil
+}
diff --git a/libgo/go/net/sock_posix.go b/libgo/go/net/sock_posix.go
index 12015ef0acd..9cd149e466b 100644
--- a/libgo/go/net/sock_posix.go
+++ b/libgo/go/net/sock_posix.go
@@ -17,15 +17,10 @@ var listenerBacklog = maxListenerBacklog()
 
 // Generic socket creation.
 func socket(net string, f, t, p int, ipv6only bool, ulsa, ursa syscall.Sockaddr, deadline time.Time, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err error) {
-	// See ../syscall/exec_unix.go for description of ForkLock.
-	syscall.ForkLock.RLock()
-	s, err := syscall.Socket(f, t, p)
+	s, err := sysSocket(f, t, p)
 	if err != nil {
-		syscall.ForkLock.RUnlock()
 		return nil, err
 	}
-	syscall.CloseOnExec(s)
-	syscall.ForkLock.RUnlock()
 
 	if err = setDefaultSockopts(s, f, t, ipv6only); err != nil {
 		closesocket(s)
diff --git a/libgo/go/net/sock_windows.go b/libgo/go/net/sock_windows.go
index cce6181c9e5..fc5d9e5de21 100644
--- a/libgo/go/net/sock_windows.go
+++ b/libgo/go/net/sock_windows.go
@@ -41,3 +41,14 @@ func listenerSockaddr(s syscall.Handle, f int, la syscall.Sockaddr, toAddr func(
 	}
 	return la, nil
 }
+
+func sysSocket(f, t, p int) (syscall.Handle, error) {
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	syscall.ForkLock.RLock()
+	s, err := syscall.Socket(f, t, p)
+	if err == nil {
+		syscall.CloseOnExec(s)
+	}
+	syscall.ForkLock.RUnlock()
+	return s, err
+}
diff --git a/libgo/go/net/sys_cloexec.go b/libgo/go/net/sys_cloexec.go
new file mode 100644
index 00000000000..75d5688a163
--- /dev/null
+++ b/libgo/go/net/sys_cloexec.go
@@ -0,0 +1,54 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file implements sysSocket and accept for platforms that do not
+// provide a fast path for setting SetNonblock and CloseOnExec.
+
+// +build darwin freebsd netbsd openbsd
+
+package net
+
+import "syscall"
+
+// Wrapper around the socket system call that marks the returned file
+// descriptor as nonblocking and close-on-exec.
+func sysSocket(f, t, p int) (int, error) {
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	syscall.ForkLock.RLock()
+	s, err := syscall.Socket(f, t, p)
+	if err == nil {
+		syscall.CloseOnExec(s)
+	}
+	syscall.ForkLock.RUnlock()
+	if err != nil {
+		return -1, err
+	}
+	if err = syscall.SetNonblock(s, true); err != nil {
+		syscall.Close(s)
+		return -1, err
+	}
+	return s, nil
+}
+
+// Wrapper around the accept system call that marks the returned file
+// descriptor as nonblocking and close-on-exec.
+func accept(fd int) (int, syscall.Sockaddr, error) {
+	// See ../syscall/exec_unix.go for description of ForkLock.
+	// It is okay to hold the lock across syscall.Accept
+	// because we have put fd.sysfd into non-blocking mode.
+	syscall.ForkLock.RLock()
+	nfd, sa, err := syscall.Accept(fd)
+	if err == nil {
+		syscall.CloseOnExec(nfd)
+	}
+	syscall.ForkLock.RUnlock()
+	if err != nil {
+		return -1, nil, err
+	}
+	if err = syscall.SetNonblock(nfd, true); err != nil {
+		syscall.Close(nfd)
+		return -1, nil, err
+	}
+	return nfd, sa, nil
+}
diff --git a/libgo/go/net/tcp_test.go b/libgo/go/net/tcp_test.go
index bca748827ce..1d54b3adcc7 100644
--- a/libgo/go/net/tcp_test.go
+++ b/libgo/go/net/tcp_test.go
@@ -159,8 +159,7 @@ var tcpListenerNameTests = []struct {
 
 func TestTCPListenerName(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 
 	for _, tt := range tcpListenerNameTests {
diff --git a/libgo/go/net/tcpsock_posix.go b/libgo/go/net/tcpsock_posix.go
index 4f9159566f3..bd5a2a28775 100644
--- a/libgo/go/net/tcpsock_posix.go
+++ b/libgo/go/net/tcpsock_posix.go
@@ -26,11 +26,6 @@ func sockaddrToTCP(sa syscall.Sockaddr) Addr {
 		return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port}
 	case *syscall.SockaddrInet6:
 		return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneToString(int(sa.ZoneId))}
-	default:
-		if sa != nil {
-			// Diagnose when we will turn a non-nil sockaddr into a nil.
-			panic("unexpected type in sockaddrToTCP")
-		}
 	}
 	return nil
 }
diff --git a/libgo/go/net/timeout_test.go b/libgo/go/net/timeout_test.go
index 21223cc74ad..7cf45ca0a09 100644
--- a/libgo/go/net/timeout_test.go
+++ b/libgo/go/net/timeout_test.go
@@ -27,8 +27,7 @@ type copyRes struct {
 func TestAcceptTimeout(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	ln := newLocalListener(t).(*TCPListener)
@@ -60,16 +59,22 @@ func TestAcceptTimeout(t *testing.T) {
 	default:
 	}
 	ln.Close()
-	if err := <-errc; err.(*OpError).Err != errClosing {
-		t.Fatalf("Accept: expected err %v, got %v", errClosing, err.(*OpError).Err)
+	switch nerr := <-errc; err := nerr.(type) {
+	case *OpError:
+		if err.Err != errClosing {
+			t.Fatalf("Accept: expected err %v, got %v", errClosing, err)
+		}
+	default:
+		if err != errClosing {
+			t.Fatalf("Accept: expected err %v, got %v", errClosing, err)
+		}
 	}
 }
 
 func TestReadTimeout(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	ln := newLocalListener(t)
@@ -109,16 +114,22 @@ func TestReadTimeout(t *testing.T) {
 	default:
 	}
 	c.Close()
-	if err := <-errc; err.(*OpError).Err != errClosing {
-		t.Fatalf("Read: expected err %v, got %v", errClosing, err.(*OpError).Err)
+	switch nerr := <-errc; err := nerr.(type) {
+	case *OpError:
+		if err.Err != errClosing {
+			t.Fatalf("Read: expected err %v, got %v", errClosing, err)
+		}
+	default:
+		if err != errClosing {
+			t.Fatalf("Read: expected err %v, got %v", errClosing, err)
+		}
 	}
 }
 
 func TestWriteTimeout(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	ln := newLocalListener(t)
@@ -164,8 +175,15 @@ func TestWriteTimeout(t *testing.T) {
 	default:
 	}
 	c.Close()
-	if err := <-errc; err.(*OpError).Err != errClosing {
-		t.Fatalf("Write: expected err %v, got %v", errClosing, err.(*OpError).Err)
+	switch nerr := <-errc; err := nerr.(type) {
+	case *OpError:
+		if err.Err != errClosing {
+			t.Fatalf("Write: expected err %v, got %v", errClosing, err)
+		}
+	default:
+		if err != errClosing {
+			t.Fatalf("Write: expected err %v, got %v", errClosing, err)
+		}
 	}
 }
 
@@ -217,8 +235,7 @@ func testTimeout(t *testing.T, net, addr string, readFrom bool) {
 func TestTimeoutUDP(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	// set up a listener that won't talk back
@@ -235,8 +252,7 @@ func TestTimeoutUDP(t *testing.T) {
 func TestTimeoutTCP(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	// set up a listener that won't talk back
@@ -252,8 +268,7 @@ func TestTimeoutTCP(t *testing.T) {
 func TestDeadlineReset(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	ln, err := Listen("tcp", "127.0.0.1:0")
 	if err != nil {
@@ -281,8 +296,7 @@ func TestDeadlineReset(t *testing.T) {
 func TestTimeoutAccept(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	ln, err := Listen("tcp", "127.0.0.1:0")
 	if err != nil {
@@ -308,13 +322,11 @@ func TestTimeoutAccept(t *testing.T) {
 func TestReadWriteDeadline(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	if !canCancelIO {
-		t.Logf("skipping test on this system")
-		return
+		t.Skip("skipping test on this system")
 	}
 	const (
 		readTimeout  = 50 * time.Millisecond
@@ -574,8 +586,7 @@ func TestWriteDeadlineBufferAvailable(t *testing.T) {
 func TestProlongTimeout(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	ln := newLocalListener(t)
diff --git a/libgo/go/net/udp_test.go b/libgo/go/net/udp_test.go
index d3594b40a9e..220422e132e 100644
--- a/libgo/go/net/udp_test.go
+++ b/libgo/go/net/udp_test.go
@@ -43,8 +43,7 @@ func TestResolveUDPAddr(t *testing.T) {
 func TestWriteToUDP(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	l, err := ListenPacket("udp", "127.0.0.1:0")
@@ -130,8 +129,7 @@ var udpConnLocalNameTests = []struct {
 
 func TestUDPConnLocalName(t *testing.T) {
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 
 	for _, tt := range udpConnLocalNameTests {
diff --git a/libgo/go/net/udpsock_posix.go b/libgo/go/net/udpsock_posix.go
index b7de678f928..385cd902eb8 100644
--- a/libgo/go/net/udpsock_posix.go
+++ b/libgo/go/net/udpsock_posix.go
@@ -211,25 +211,22 @@ func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, e
 		return nil, UnknownNetworkError(net)
 	}
 	if gaddr == nil || gaddr.IP == nil {
-		return nil, &OpError{"listenmulticast", net, nil, errMissingAddress}
+		return nil, &OpError{"listen", net, nil, errMissingAddress}
 	}
 	fd, err := internetSocket(net, gaddr.toAddr(), nil, noDeadline, syscall.SOCK_DGRAM, 0, "listen", sockaddrToUDP)
 	if err != nil {
 		return nil, err
 	}
 	c := newUDPConn(fd)
-	ip4 := gaddr.IP.To4()
-	if ip4 != nil {
-		err := listenIPv4MulticastUDP(c, ifi, ip4)
-		if err != nil {
+	if ip4 := gaddr.IP.To4(); ip4 != nil {
+		if err := listenIPv4MulticastUDP(c, ifi, ip4); err != nil {
 			c.Close()
-			return nil, err
+			return nil, &OpError{"listen", net, &IPAddr{IP: ip4}, err}
 		}
 	} else {
-		err := listenIPv6MulticastUDP(c, ifi, gaddr.IP)
-		if err != nil {
+		if err := listenIPv6MulticastUDP(c, ifi, gaddr.IP); err != nil {
 			c.Close()
-			return nil, err
+			return nil, &OpError{"listen", net, &IPAddr{IP: gaddr.IP}, err}
 		}
 	}
 	return c, nil
@@ -237,17 +234,14 @@ func ListenMulticastUDP(net string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, e
 
 func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
 	if ifi != nil {
-		err := setIPv4MulticastInterface(c.fd, ifi)
-		if err != nil {
+		if err := setIPv4MulticastInterface(c.fd, ifi); err != nil {
 			return err
 		}
 	}
-	err := setIPv4MulticastLoopback(c.fd, false)
-	if err != nil {
+	if err := setIPv4MulticastLoopback(c.fd, false); err != nil {
 		return err
 	}
-	err = joinIPv4GroupUDP(c, ifi, ip)
-	if err != nil {
+	if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
 		return err
 	}
 	return nil
@@ -255,34 +249,15 @@ func listenIPv4MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
 
 func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
 	if ifi != nil {
-		err := setIPv6MulticastInterface(c.fd, ifi)
-		if err != nil {
+		if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
 			return err
 		}
 	}
-	err := setIPv6MulticastLoopback(c.fd, false)
-	if err != nil {
+	if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
 		return err
 	}
-	err = joinIPv6GroupUDP(c, ifi, ip)
-	if err != nil {
+	if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
 		return err
 	}
 	return nil
 }
-
-func joinIPv4GroupUDP(c *UDPConn, ifi *Interface, ip IP) error {
-	err := joinIPv4Group(c.fd, ifi, ip)
-	if err != nil {
-		return &OpError{"joinipv4group", c.fd.net, &IPAddr{IP: ip}, err}
-	}
-	return nil
-}
-
-func joinIPv6GroupUDP(c *UDPConn, ifi *Interface, ip IP) error {
-	err := joinIPv6Group(c.fd, ifi, ip)
-	if err != nil {
-		return &OpError{"joinipv6group", c.fd.net, &IPAddr{IP: ip}, err}
-	}
-	return nil
-}
diff --git a/libgo/go/net/unicast_posix_test.go b/libgo/go/net/unicast_posix_test.go
index e1d4b0d47aa..a8855cab7da 100644
--- a/libgo/go/net/unicast_posix_test.go
+++ b/libgo/go/net/unicast_posix_test.go
@@ -46,8 +46,7 @@ var listenerTests = []struct {
 func TestTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	for _, tt := range listenerTests {
@@ -71,8 +70,7 @@ func TestTCPListener(t *testing.T) {
 func TestUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9", "windows":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	toudpnet := func(net string) string {
@@ -106,7 +104,7 @@ func TestUDPListener(t *testing.T) {
 func TestSimpleTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
+		t.Skipf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -128,7 +126,7 @@ func TestSimpleTCPListener(t *testing.T) {
 func TestSimpleUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
+		t.Skipf("skipping test on %q", runtime.GOOS)
 		return
 	}
 
@@ -230,8 +228,7 @@ var dualStackListenerTests = []struct {
 func TestDualStackTCPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	if !supportsIPv6 {
 		return
@@ -263,8 +260,7 @@ func TestDualStackTCPListener(t *testing.T) {
 func TestDualStackUDPListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	if !supportsIPv6 {
 		return
@@ -467,8 +463,7 @@ var prohibitionaryDialArgTests = []struct {
 func TestProhibitionaryDialArgs(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 	// This test requires both IPv6 and IPv6 IPv4-mapping functionality.
 	if !supportsIPv4map || testing.Short() || !*testExternal {
@@ -490,13 +485,11 @@ func TestProhibitionaryDialArgs(t *testing.T) {
 func TestWildWildcardListener(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
-		t.Logf("skipping test on %q", runtime.GOOS)
-		return
+		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
 	if testing.Short() || !*testExternal {
-		t.Logf("skipping test to avoid external network")
-		return
+		t.Skip("skipping test to avoid external network")
 	}
 
 	defer func() {
diff --git a/libgo/go/net/url/url.go b/libgo/go/net/url/url.go
index 71758fe49e0..68f2c2f6e7e 100644
--- a/libgo/go/net/url/url.go
+++ b/libgo/go/net/url/url.go
@@ -386,7 +386,7 @@ func parse(rawurl string, viaRequest bool) (url *URL, err error) {
 		}
 	}
 
-	if (url.Scheme != "" || !viaRequest) && strings.HasPrefix(rest, "//") && !strings.HasPrefix(rest, "///") {
+	if (url.Scheme != "" || !viaRequest && !strings.HasPrefix(rest, "///")) && strings.HasPrefix(rest, "//") {
 		var authority string
 		authority, rest = split(rest[2:], '/', false)
 		url.User, url.Host, err = parseAuthority(authority)
@@ -434,30 +434,35 @@ func parseAuthority(authority string) (user *Userinfo, host string, err error) {
 
 // String reassembles the URL into a valid URL string.
 func (u *URL) String() string {
-	// TODO: Rewrite to use bytes.Buffer
-	result := ""
+	var buf bytes.Buffer
 	if u.Scheme != "" {
-		result += u.Scheme + ":"
+		buf.WriteString(u.Scheme)
+		buf.WriteByte(':')
 	}
 	if u.Opaque != "" {
-		result += u.Opaque
+		buf.WriteString(u.Opaque)
 	} else {
-		if u.Host != "" || u.User != nil {
-			result += "//"
+		if u.Scheme != "" || u.Host != "" || u.User != nil {
+			buf.WriteString("//")
 			if u := u.User; u != nil {
-				result += u.String() + "@"
+				buf.WriteString(u.String())
+				buf.WriteByte('@')
+			}
+			if h := u.Host; h != "" {
+				buf.WriteString(h)
 			}
-			result += u.Host
 		}
-		result += escape(u.Path, encodePath)
+		buf.WriteString(escape(u.Path, encodePath))
 	}
 	if u.RawQuery != "" {
-		result += "?" + u.RawQuery
+		buf.WriteByte('?')
+		buf.WriteString(u.RawQuery)
 	}
 	if u.Fragment != "" {
-		result += "#" + escape(u.Fragment, encodeFragment)
+		buf.WriteByte('#')
+		buf.WriteString(escape(u.Fragment, encodeFragment))
 	}
-	return result
+	return buf.String()
 }
 
 // Values maps a string key to a list of values.
diff --git a/libgo/go/net/url/url_test.go b/libgo/go/net/url/url_test.go
index 4d3545dadb7..cd3b0b9e8c7 100644
--- a/libgo/go/net/url/url_test.go
+++ b/libgo/go/net/url/url_test.go
@@ -122,14 +122,14 @@ var urltests = []URLTest{
 		},
 		"http:%2f%2fwww.google.com/?q=go+language",
 	},
-	// non-authority
+	// non-authority with path
 	{
 		"mailto:/webmaster@golang.org",
 		&URL{
 			Scheme: "mailto",
 			Path:   "/webmaster@golang.org",
 		},
-		"",
+		"mailto:///webmaster@golang.org", // unfortunate compromise
 	},
 	// non-authority
 	{
@@ -242,6 +242,15 @@ var urltests = []URLTest{
 		},
 		"http://www.google.com/?q=go+language#foo&bar",
 	},
+	{
+		"file:///home/adg/rabbits",
+		&URL{
+			Scheme: "file",
+			Host:   "",
+			Path:   "/home/adg/rabbits",
+		},
+		"file:///home/adg/rabbits",
+	},
 }
 
 // more useful string for debugging than fmt's struct printer
@@ -271,6 +280,30 @@ func DoTest(t *testing.T, parse func(string) (*URL, error), name string, tests [
 	}
 }
 
+func BenchmarkString(b *testing.B) {
+	b.StopTimer()
+	b.ReportAllocs()
+	for _, tt := range urltests {
+		u, err := Parse(tt.in)
+		if err != nil {
+			b.Errorf("Parse(%q) returned error %s", tt.in, err)
+			continue
+		}
+		if tt.roundtrip == "" {
+			continue
+		}
+		b.StartTimer()
+		var g string
+		for i := 0; i < b.N; i++ {
+			g = u.String()
+		}
+		b.StopTimer()
+		if w := tt.roundtrip; g != w {
+			b.Errorf("Parse(%q).String() == %q, want %q", tt.in, g, w)
+		}
+	}
+}
+
 func TestParse(t *testing.T) {
 	DoTest(t, Parse, "Parse", urltests)
 }