runtime: Remove now unnecessary pad field from ParFor.

    
    It is not needed due to the removal of the ctx field.
    
    Reviewed-on: https://go-review.googlesource.com/16525

From-SVN: r229616

31 files changed, 1133 insertions, 229 deletions

diff --git a/libgo/go/os/env.go b/libgo/go/os/env.go
index d0494a4..a4ede15 100644
--- a/libgo/go/os/env.go
+++ b/libgo/go/os/env.go
@@ -33,7 +33,7 @@ func ExpandEnv(s string) string {
 	return Expand(s, Getenv)
 }
 
-// isSpellSpecialVar reports whether the character identifies a special
+// isShellSpecialVar reports whether the character identifies a special
 // shell variable such as $*.
 func isShellSpecialVar(c uint8) bool {
 	switch c {
@@ -48,7 +48,7 @@ func isAlphaNum(c uint8) bool {
 	return c == '_' || '0' <= c && c <= '9' || 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z'
 }
 
-// getName returns the name that begins the string and the number of bytes
+// getShellName returns the name that begins the string and the number of bytes
 // consumed to extract it.  If the name is enclosed in {}, it's part of a ${}
 // expansion and two more bytes are needed than the length of the name.
 func getShellName(s string) (string, int) {
@@ -81,6 +81,15 @@ func Getenv(key string) string {
 	return v
 }
 
+// LookupEnv retrieves the value of the environment variable named
+// by the key. If the variable is present in the environment the
+// value (which may be empty) is returned and the boolean is true.
+// Otherwise the returned value will be empty and the boolean will
+// be false.
+func LookupEnv(key string) (string, bool) {
+	return syscall.Getenv(key)
+}
+
 // Setenv sets the value of the environment variable named by the key.
 // It returns an error, if any.
 func Setenv(key, value string) error {
diff --git a/libgo/go/os/env_test.go b/libgo/go/os/env_test.go
index e618067..d1074cd 100644
--- a/libgo/go/os/env_test.go
+++ b/libgo/go/os/env_test.go
@@ -94,3 +94,20 @@ func TestUnsetenv(t *testing.T) {
 		t.Fatal("Unsetenv didn't clear TestUnsetenv")
 	}
 }
+
+func TestLookupEnv(t *testing.T) {
+	const smallpox = "SMALLPOX"      // No one has smallpox.
+	value, ok := LookupEnv(smallpox) // Should not exist.
+	if ok || value != "" {
+		t.Fatalf("%s=%q", smallpox, value)
+	}
+	defer Unsetenv(smallpox)
+	err := Setenv(smallpox, "virus")
+	if err != nil {
+		t.Fatalf("failed to release smallpox virus")
+	}
+	value, ok = LookupEnv(smallpox)
+	if !ok {
+		t.Errorf("smallpox release failed; world remains safe but LookupEnv is broken")
+	}
+}
diff --git a/libgo/go/os/exec.go b/libgo/go/os/exec.go
index 5aea309..15e95b9 100644
--- a/libgo/go/os/exec.go
+++ b/libgo/go/os/exec.go
@@ -13,8 +13,8 @@ import (
 // Process stores the information about a process created by StartProcess.
 type Process struct {
 	Pid    int
-	handle uintptr
-	isdone uint32 // process has been successfully waited on, non zero if true
+	handle uintptr // handle is accessed atomically on Windows
+	isdone uint32  // process has been successfully waited on, non zero if true
 }
 
 func newProcess(pid int, handle uintptr) *Process {
diff --git a/libgo/go/os/exec/exec.go b/libgo/go/os/exec/exec.go
index 72b4905..8a84e26 100644
--- a/libgo/go/os/exec/exec.go
+++ b/libgo/go/os/exec/exec.go
@@ -32,6 +32,9 @@ func (e *Error) Error() string {
 }
 
 // Cmd represents an external command being prepared or run.
+//
+// A Cmd cannot be reused after calling its Run, Output or CombinedOutput
+// methods.
 type Cmd struct {
 	// Path is the path of the command to run.
 	//
@@ -80,8 +83,8 @@ type Cmd struct {
 	// new process. It does not include standard input, standard output, or
 	// standard error. If non-nil, entry i becomes file descriptor 3+i.
 	//
-	// BUG: on OS X 10.6, child processes may sometimes inherit unwanted fds.
-	// http://golang.org/issue/2603
+	// BUG(rsc): On OS X 10.6, child processes may sometimes inherit unwanted fds.
+	// https://golang.org/issue/2603
 	ExtraFiles []*os.File
 
 	// SysProcAttr holds optional, operating system-specific attributes.
@@ -154,6 +157,11 @@ func (c *Cmd) argv() []string {
 	return []string{c.Path}
 }
 
+// skipStdinCopyError optionally specifies a function which reports
+// whether the provided the stdin copy error should be ignored.
+// It is non-nil everywhere but Plan 9, which lacks EPIPE. See exec_posix.go.
+var skipStdinCopyError func(error) bool
+
 func (c *Cmd) stdin() (f *os.File, err error) {
 	if c.Stdin == nil {
 		f, err = os.Open(os.DevNull)
@@ -177,6 +185,9 @@ func (c *Cmd) stdin() (f *os.File, err error) {
 	c.closeAfterWait = append(c.closeAfterWait, pw)
 	c.goroutine = append(c.goroutine, func() error {
 		_, err := io.Copy(pw, c.Stdin)
+		if skip := skipStdinCopyError; skip != nil && skip(err) {
+			err = nil
+		}
 		if err1 := pw.Close(); err == nil {
 			err = err1
 		}
@@ -219,6 +230,7 @@ func (c *Cmd) writerDescriptor(w io.Writer) (f *os.File, err error) {
 	c.closeAfterWait = append(c.closeAfterWait, pr)
 	c.goroutine = append(c.goroutine, func() error {
 		_, err := io.Copy(w, pr)
+		pr.Close() // in case io.Copy stopped due to write error
 		return err
 	})
 	return pw, nil
@@ -352,6 +364,10 @@ func (e *ExitError) Error() string {
 // error is of type *ExitError. Other error types may be
 // returned for I/O problems.
 //
+// If c.Stdin is not an *os.File, Wait also waits for the I/O loop
+// copying from c.Stdin into the process's standard input
+// to complete.
+//
 // Wait releases any resources associated with the Cmd.
 func (c *Cmd) Wait() error {
 	if c.Process == nil {
diff --git a/libgo/go/os/exec/exec_posix.go b/libgo/go/os/exec/exec_posix.go
new file mode 100644
index 0000000..5e11137
--- /dev/null
+++ b/libgo/go/os/exec/exec_posix.go
@@ -0,0 +1,24 @@
+// Copyright 2015 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.
+
+// +build !plan9
+
+package exec
+
+import (
+	"os"
+	"syscall"
+)
+
+func init() {
+	skipStdinCopyError = func(err error) bool {
+		// Ignore EPIPE errors copying to stdin if the program
+		// completed successfully otherwise.
+		// See Issue 9173.
+		pe, ok := err.(*os.PathError)
+		return ok &&
+			pe.Op == "write" && pe.Path == "|1" &&
+			pe.Err == syscall.EPIPE
+	}
+}
diff --git a/libgo/go/os/exec/exec_test.go b/libgo/go/os/exec/exec_test.go
index f9ffde6..f4c025e 100644
--- a/libgo/go/os/exec/exec_test.go
+++ b/libgo/go/os/exec/exec_test.go
@@ -11,6 +11,7 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"internal/testenv"
 	"io"
 	"io/ioutil"
 	"log"
@@ -28,9 +29,8 @@ import (
 )
 
 func helperCommand(t *testing.T, s ...string) *exec.Cmd {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
-	}
+	testenv.MustHaveExec(t)
+
 	cs := []string{"-test.run=TestHelperProcess", "--"}
 	cs = append(cs, s...)
 	cmd := exec.Command(os.Args[0], cs...)
@@ -53,6 +53,8 @@ func TestEcho(t *testing.T) {
 }
 
 func TestCommandRelativeName(t *testing.T) {
+	testenv.MustHaveExec(t)
+
 	// Run our own binary as a relative path
 	// (e.g. "_test/exec.test") our parent directory.
 	base := filepath.Base(os.Args[0]) // "exec.test"
@@ -250,6 +252,12 @@ func TestPipeLookPathLeak(t *testing.T) {
 }
 
 func numOpenFDS(t *testing.T) (n int, lsof []byte) {
+	if runtime.GOOS == "android" {
+		// Android's stock lsof does not obey the -p option,
+		// so extra filtering is needed. (golang.org/issue/10206)
+		return numOpenFDsAndroid(t)
+	}
+
 	lsof, err := exec.Command("lsof", "-b", "-n", "-p", strconv.Itoa(os.Getpid())).Output()
 	if err != nil {
 		t.Skip("skipping test; error finding or running lsof")
@@ -257,6 +265,45 @@ func numOpenFDS(t *testing.T) (n int, lsof []byte) {
 	return bytes.Count(lsof, []byte("\n")), lsof
 }
 
+func numOpenFDsAndroid(t *testing.T) (n int, lsof []byte) {
+	raw, err := exec.Command("lsof").Output()
+	if err != nil {
+		t.Skip("skipping test; error finding or running lsof")
+	}
+
+	// First find the PID column index by parsing the first line, and
+	// select lines containing pid in the column.
+	pid := []byte(strconv.Itoa(os.Getpid()))
+	pidCol := -1
+
+	s := bufio.NewScanner(bytes.NewReader(raw))
+	for s.Scan() {
+		line := s.Bytes()
+		fields := bytes.Fields(line)
+		if pidCol < 0 {
+			for i, v := range fields {
+				if bytes.Equal(v, []byte("PID")) {
+					pidCol = i
+					break
+				}
+			}
+			lsof = append(lsof, line...)
+			continue
+		}
+		if bytes.Equal(fields[pidCol], pid) {
+			lsof = append(lsof, '\n')
+			lsof = append(lsof, line...)
+		}
+	}
+	if pidCol < 0 {
+		t.Fatal("error processing lsof output: unexpected header format")
+	}
+	if err := s.Err(); err != nil {
+		t.Fatalf("error processing lsof output: %v", err)
+	}
+	return bytes.Count(lsof, []byte("\n")), lsof
+}
+
 var testedAlreadyLeaked = false
 
 // basefds returns the number of expected file descriptors
@@ -275,15 +322,15 @@ func closeUnexpectedFds(t *testing.T, m string) {
 }
 
 func TestExtraFilesFDShuffle(t *testing.T) {
-	t.Skip("flaky test; see http://golang.org/issue/5780")
+	t.Skip("flaky test; see https://golang.org/issue/5780")
 	switch runtime.GOOS {
 	case "darwin":
-		// TODO(cnicolaou): http://golang.org/issue/2603
+		// TODO(cnicolaou): https://golang.org/issue/2603
 		// leads to leaked file descriptors in this test when it's
 		// run from a builder.
 		closeUnexpectedFds(t, "TestExtraFilesFDShuffle")
 	case "netbsd":
-		// http://golang.org/issue/3955
+		// https://golang.org/issue/3955
 		closeUnexpectedFds(t, "TestExtraFilesFDShuffle")
 	case "windows":
 		t.Skip("no operating system support; skipping")
@@ -379,8 +426,9 @@ func TestExtraFilesFDShuffle(t *testing.T) {
 }
 
 func TestExtraFiles(t *testing.T) {
-	switch runtime.GOOS {
-	case "nacl", "windows":
+	testenv.MustHaveExec(t)
+
+	if runtime.GOOS == "windows" {
 		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
 
@@ -608,21 +656,21 @@ func TestHelperProcess(*testing.T) {
 			// file descriptors...
 		case "darwin":
 			// TODO(bradfitz): broken? Sometimes.
-			// http://golang.org/issue/2603
+			// https://golang.org/issue/2603
 			// Skip this additional part of the test for now.
 		case "netbsd":
 			// TODO(jsing): This currently fails on NetBSD due to
 			// the cloned file descriptors that result from opening
 			// /dev/urandom.
-			// http://golang.org/issue/3955
+			// https://golang.org/issue/3955
 		case "plan9":
 			// TODO(0intro): Determine why Plan 9 is leaking
 			// file descriptors.
-			// http://golang.org/issue/7118
+			// https://golang.org/issue/7118
 		case "solaris":
 			// TODO(aram): This fails on Solaris because libc opens
 			// its own files, as it sees fit. Darwin does the same,
-			// see: http://golang.org/issue/2603
+			// see: https://golang.org/issue/2603
 		default:
 			// Now verify that there are no other open fds.
 			var files []*os.File
@@ -721,3 +769,54 @@ func TestHelperProcess(*testing.T) {
 		os.Exit(2)
 	}
 }
+
+// Issue 9173: ignore stdin pipe writes if the program completes successfully.
+func TestIgnorePipeErrorOnSuccess(t *testing.T) {
+	testenv.MustHaveExec(t)
+
+	// We really only care about testing this on Unixy things.
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Skipf("skipping test on %q", runtime.GOOS)
+	}
+
+	cmd := helperCommand(t, "echo", "foo")
+	var out bytes.Buffer
+	cmd.Stdin = strings.NewReader(strings.Repeat("x", 10<<20))
+	cmd.Stdout = &out
+	if err := cmd.Run(); err != nil {
+		t.Fatal(err)
+	}
+	if got, want := out.String(), "foo\n"; got != want {
+		t.Errorf("output = %q; want %q", got, want)
+	}
+}
+
+type badWriter struct{}
+
+func (w *badWriter) Write(data []byte) (int, error) {
+	return 0, io.ErrUnexpectedEOF
+}
+
+func TestClosePipeOnCopyError(t *testing.T) {
+	testenv.MustHaveExec(t)
+
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Skipf("skipping test on %s - no yes command", runtime.GOOS)
+	}
+	cmd := exec.Command("yes")
+	cmd.Stdout = new(badWriter)
+	c := make(chan int, 1)
+	go func() {
+		err := cmd.Run()
+		if err == nil {
+			t.Errorf("yes completed successfully")
+		}
+		c <- 1
+	}()
+	select {
+	case <-c:
+		// ok
+	case <-time.After(5 * time.Second):
+		t.Fatalf("yes got stuck writing to bad writer")
+	}
+}
diff --git a/libgo/go/os/exec_posix.go b/libgo/go/os/exec_posix.go
index fb9d291..94dd04b 100644
--- a/libgo/go/os/exec_posix.go
+++ b/libgo/go/os/exec_posix.go
@@ -81,33 +81,6 @@ func (p *ProcessState) sysUsage() interface{} {
 	return p.rusage
 }
 
-// Convert i to decimal string.
-func itod(i int) string {
-	if i == 0 {
-		return "0"
-	}
-
-	u := uint64(i)
-	if i < 0 {
-		u = -u
-	}
-
-	// Assemble decimal in reverse order.
-	var b [32]byte
-	bp := len(b)
-	for ; u > 0; u /= 10 {
-		bp--
-		b[bp] = byte(u%10) + '0'
-	}
-
-	if i < 0 {
-		bp--
-		b[bp] = '-'
-	}
-
-	return string(b[bp:])
-}
-
 func (p *ProcessState) String() string {
 	if p == nil {
 		return "<nil>"
@@ -116,13 +89,13 @@ func (p *ProcessState) String() string {
 	res := ""
 	switch {
 	case status.Exited():
-		res = "exit status " + itod(status.ExitStatus())
+		res = "exit status " + itoa(status.ExitStatus())
 	case status.Signaled():
 		res = "signal: " + status.Signal().String()
 	case status.Stopped():
 		res = "stop signal: " + status.StopSignal().String()
 		if status.StopSignal() == syscall.SIGTRAP && status.TrapCause() != 0 {
-			res += " (trap " + itod(status.TrapCause()) + ")"
+			res += " (trap " + itoa(status.TrapCause()) + ")"
 		}
 	case status.Continued():
 		res = "continued"
diff --git a/libgo/go/os/exec_windows.go b/libgo/go/os/exec_windows.go
index 393393b..3264271 100644
--- a/libgo/go/os/exec_windows.go
+++ b/libgo/go/os/exec_windows.go
@@ -7,13 +7,15 @@ package os
 import (
 	"errors"
 	"runtime"
+	"sync/atomic"
 	"syscall"
 	"time"
 	"unsafe"
 )
 
 func (p *Process) wait() (ps *ProcessState, err error) {
-	s, e := syscall.WaitForSingleObject(syscall.Handle(p.handle), syscall.INFINITE)
+	handle := atomic.LoadUintptr(&p.handle)
+	s, e := syscall.WaitForSingleObject(syscall.Handle(handle), syscall.INFINITE)
 	switch s {
 	case syscall.WAIT_OBJECT_0:
 		break
@@ -23,12 +25,12 @@ func (p *Process) wait() (ps *ProcessState, err error) {
 		return nil, errors.New("os: unexpected result from WaitForSingleObject")
 	}
 	var ec uint32
-	e = syscall.GetExitCodeProcess(syscall.Handle(p.handle), &ec)
+	e = syscall.GetExitCodeProcess(syscall.Handle(handle), &ec)
 	if e != nil {
 		return nil, NewSyscallError("GetExitCodeProcess", e)
 	}
 	var u syscall.Rusage
-	e = syscall.GetProcessTimes(syscall.Handle(p.handle), &u.CreationTime, &u.ExitTime, &u.KernelTime, &u.UserTime)
+	e = syscall.GetProcessTimes(syscall.Handle(handle), &u.CreationTime, &u.ExitTime, &u.KernelTime, &u.UserTime)
 	if e != nil {
 		return nil, NewSyscallError("GetProcessTimes", e)
 	}
@@ -53,7 +55,8 @@ func terminateProcess(pid, exitcode int) error {
 }
 
 func (p *Process) signal(sig Signal) error {
-	if p.handle == uintptr(syscall.InvalidHandle) {
+	handle := atomic.LoadUintptr(&p.handle)
+	if handle == uintptr(syscall.InvalidHandle) {
 		return syscall.EINVAL
 	}
 	if p.done() {
@@ -67,14 +70,15 @@ func (p *Process) signal(sig Signal) error {
 }
 
 func (p *Process) release() error {
-	if p.handle == uintptr(syscall.InvalidHandle) {
+	handle := atomic.LoadUintptr(&p.handle)
+	if handle == uintptr(syscall.InvalidHandle) {
 		return syscall.EINVAL
 	}
-	e := syscall.CloseHandle(syscall.Handle(p.handle))
+	e := syscall.CloseHandle(syscall.Handle(handle))
 	if e != nil {
 		return NewSyscallError("CloseHandle", e)
 	}
-	p.handle = uintptr(syscall.InvalidHandle)
+	atomic.StoreUintptr(&p.handle, uintptr(syscall.InvalidHandle))
 	// no need for a finalizer anymore
 	runtime.SetFinalizer(p, nil)
 	return nil
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go
index e12428c..8c0e3ff 100644
--- a/libgo/go/os/file.go
+++ b/libgo/go/os/file.go
@@ -192,7 +192,7 @@ func (f *File) Seek(offset int64, whence int) (ret int64, err error) {
 
 // WriteString is like Write, but writes the contents of string s rather than
 // a slice of bytes.
-func (f *File) WriteString(s string) (ret int, err error) {
+func (f *File) WriteString(s string) (n int, err error) {
 	if f == nil {
 		return 0, ErrInvalid
 	}
@@ -203,9 +203,16 @@ func (f *File) WriteString(s string) (ret int, err error) {
 // If there is an error, it will be of type *PathError.
 func Mkdir(name string, perm FileMode) error {
 	e := syscall.Mkdir(name, syscallMode(perm))
+
 	if e != nil {
 		return &PathError{"mkdir", name, e}
 	}
+
+	// mkdir(2) itself won't handle the sticky bit on *BSD and Solaris
+	if !supportsCreateWithStickyBit && perm&ModeSticky != 0 {
+		Chmod(name, perm)
+	}
+
 	return nil
 }
 
@@ -235,16 +242,16 @@ func (f *File) Chdir() error {
 // the returned file can be used for reading; the associated file
 // descriptor has mode O_RDONLY.
 // If there is an error, it will be of type *PathError.
-func Open(name string) (file *File, err error) {
+func Open(name string) (*File, error) {
 	return OpenFile(name, O_RDONLY, 0)
 }
 
-// Create creates the named file mode 0666 (before umask), truncating
-// it if it already exists.  If successful, methods on the returned
+// Create creates the named file with mode 0666 (before umask), truncating
+// it if it already exists. If successful, methods on the returned
 // File can be used for I/O; the associated file descriptor has mode
 // O_RDWR.
 // If there is an error, it will be of type *PathError.
-func Create(name string) (file *File, err error) {
+func Create(name string) (*File, error) {
 	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
 }
 
@@ -252,6 +259,7 @@ func Create(name string) (file *File, err error) {
 var lstat = Lstat
 
 // Rename renames (moves) a file. OS-specific restrictions might apply.
+// If there is an error, it will be of type *LinkError.
 func Rename(oldpath, newpath string) error {
 	return rename(oldpath, newpath)
 }
diff --git a/libgo/go/os/file_plan9.go b/libgo/go/os/file_plan9.go
index 132594e..085ebc4 100644
--- a/libgo/go/os/file_plan9.go
+++ b/libgo/go/os/file_plan9.go
@@ -79,7 +79,7 @@ func syscallMode(i FileMode) (o uint32) {
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
-func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
 	var (
 		fd     int
 		e      error
@@ -159,7 +159,7 @@ func (file *file) close() error {
 
 // Stat returns the FileInfo structure describing file.
 // If there is an error, it will be of type *PathError.
-func (f *File) Stat() (fi FileInfo, err error) {
+func (f *File) Stat() (FileInfo, error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
@@ -224,7 +224,7 @@ func (f *File) Chmod(mode FileMode) error {
 // Sync commits the current contents of the file to stable storage.
 // Typically, this means flushing the file system's in-memory copy
 // of recently written data to disk.
-func (f *File) Sync() (err error) {
+func (f *File) Sync() error {
 	if f == nil {
 		return ErrInvalid
 	}
@@ -319,7 +319,7 @@ func hasPrefix(s, prefix string) bool {
 	return len(s) >= len(prefix) && s[0:len(prefix)] == prefix
 }
 
-// Variant of LastIndex from the strings package.
+// LastIndexByte from the strings package.
 func lastIndex(s string, sep byte) int {
 	for i := len(s) - 1; i >= 0; i-- {
 		if s[i] == sep {
diff --git a/libgo/go/os/file_posix.go b/libgo/go/os/file_posix.go
index fbb3b5e4..6d8076f 100644
--- a/libgo/go/os/file_posix.go
+++ b/libgo/go/os/file_posix.go
@@ -28,14 +28,6 @@ func Readlink(name string) (string, error) {
 	}
 }
 
-func rename(oldname, newname string) error {
-	e := syscall.Rename(oldname, newname)
-	if e != nil {
-		return &LinkError{"rename", oldname, newname, e}
-	}
-	return nil
-}
-
 // syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
 func syscallMode(i FileMode) (o uint32) {
 	o |= uint32(i.Perm())
@@ -122,7 +114,7 @@ func (f *File) Truncate(size int64) error {
 // Sync commits the current contents of the file to stable storage.
 // Typically, this means flushing the file system's in-memory copy
 // of recently written data to disk.
-func (f *File) Sync() (err error) {
+func (f *File) Sync() error {
 	if f == nil {
 		return ErrInvalid
 	}
diff --git a/libgo/go/os/file_unix.go b/libgo/go/os/file_unix.go
index b25e62f..7a18987 100644
--- a/libgo/go/os/file_unix.go
+++ b/libgo/go/os/file_unix.go
@@ -12,6 +12,14 @@ import (
 	"syscall"
 )
 
+func rename(oldname, newname string) error {
+	e := syscall.Rename(oldname, newname)
+	if e != nil {
+		return &LinkError{"rename", oldname, newname, e}
+	}
+	return nil
+}
+
 // File represents an open file descriptor.
 type File struct {
 	*file
@@ -73,12 +81,24 @@ const DevNull = "/dev/null"
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
-func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
+	chmod := false
+	if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
+		if _, err := Stat(name); IsNotExist(err) {
+			chmod = true
+		}
+	}
+
 	r, e := syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
 	if e != nil {
 		return nil, &PathError{"open", name, e}
 	}
 
+	// open(2) itself won't handle the sticky bit on *BSD and Solaris
+	if chmod {
+		Chmod(name, perm)
+	}
+
 	// There's a race here with fork/exec, which we are
 	// content to live with.  See ../syscall/exec_unix.go.
 	if !supportsCloseOnExec {
@@ -126,12 +146,12 @@ func (file *file) close() error {
 
 // Stat returns the FileInfo structure describing file.
 // If there is an error, it will be of type *PathError.
-func (f *File) Stat() (fi FileInfo, err error) {
+func (f *File) Stat() (FileInfo, error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
 	var stat syscall.Stat_t
-	err = syscall.Fstat(f.fd, &stat)
+	err := syscall.Fstat(f.fd, &stat)
 	if err != nil {
 		return nil, &PathError{"stat", f.name, err}
 	}
@@ -140,9 +160,9 @@ func (f *File) Stat() (fi FileInfo, err error) {
 
 // Stat returns a FileInfo describing the named file.
 // If there is an error, it will be of type *PathError.
-func Stat(name string) (fi FileInfo, err error) {
+func Stat(name string) (FileInfo, error) {
 	var stat syscall.Stat_t
-	err = syscall.Stat(name, &stat)
+	err := syscall.Stat(name, &stat)
 	if err != nil {
 		return nil, &PathError{"stat", name, err}
 	}
@@ -153,9 +173,9 @@ func Stat(name string) (fi FileInfo, err error) {
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func Lstat(name string) (fi FileInfo, err error) {
+func Lstat(name string) (FileInfo, error) {
 	var stat syscall.Stat_t
-	err = syscall.Lstat(name, &stat)
+	err := syscall.Lstat(name, &stat)
 	if err != nil {
 		return nil, &PathError{"lstat", name, err}
 	}
diff --git a/libgo/go/os/os_test.go b/libgo/go/os/os_test.go
index 7a86efa..78201f2c 100644
--- a/libgo/go/os/os_test.go
+++ b/libgo/go/os/os_test.go
@@ -9,6 +9,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"internal/testenv"
 	"io"
 	"io/ioutil"
 	. "os"
@@ -21,7 +22,6 @@ import (
 	"sync"
 	"syscall"
 	"testing"
-	"text/template"
 	"time"
 )
 
@@ -41,18 +41,33 @@ type sysDir struct {
 	files []string
 }
 
-var sysdir = func() (sd *sysDir) {
+var sysdir = func() *sysDir {
 	switch runtime.GOOS {
 	case "android":
-		sd = &sysDir{
+		return &sysDir{
 			"/system/etc",
 			[]string{
 				"audio_policy.conf",
 				"system_fonts.xml",
 			},
 		}
+	case "darwin":
+		switch runtime.GOARCH {
+		case "arm", "arm64":
+			wd, err := syscall.Getwd()
+			if err != nil {
+				wd = err.Error()
+			}
+			return &sysDir{
+				filepath.Join(wd, "..", ".."),
+				[]string{
+					"ResourceRules.plist",
+					"Info.plist",
+				},
+			}
+		}
 	case "windows":
-		sd = &sysDir{
+		return &sysDir{
 			Getenv("SystemRoot") + "\\system32\\drivers\\etc",
 			[]string{
 				"networks",
@@ -61,24 +76,22 @@ var sysdir = func() (sd *sysDir) {
 			},
 		}
 	case "plan9":
-		sd = &sysDir{
+		return &sysDir{
 			"/lib/ndb",
 			[]string{
 				"common",
 				"local",
 			},
 		}
-	default:
-		sd = &sysDir{
-			"/etc",
-			[]string{
-				"group",
-				"hosts",
-				"passwd",
-			},
-		}
 	}
-	return
+	return &sysDir{
+		"/etc",
+		[]string{
+			"group",
+			"hosts",
+			"passwd",
+		},
+	}
 }()
 
 func size(name string, t *testing.T) int64 {
@@ -112,15 +125,22 @@ func equal(name1, name2 string) (r bool) {
 	return
 }
 
-func newFile(testName string, t *testing.T) (f *File) {
-	// Use a local file system, not NFS.
-	// On Unix, override $TMPDIR in case the user
-	// has it set to an NFS-mounted directory.
-	dir := ""
-	if runtime.GOOS != "android" && runtime.GOOS != "windows" {
-		dir = "/tmp"
+// localTmp returns a local temporary directory not on NFS.
+func localTmp() string {
+	switch runtime.GOOS {
+	case "android", "windows":
+		return TempDir()
+	case "darwin":
+		switch runtime.GOARCH {
+		case "arm", "arm64":
+			return TempDir()
+		}
 	}
-	f, err := ioutil.TempFile(dir, "_Go_"+testName)
+	return "/tmp"
+}
+
+func newFile(testName string, t *testing.T) (f *File) {
+	f, err := ioutil.TempFile(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempFile %s: %s", testName, err)
 	}
@@ -128,14 +148,7 @@ func newFile(testName string, t *testing.T) (f *File) {
 }
 
 func newDir(testName string, t *testing.T) (name string) {
-	// Use a local file system, not NFS.
-	// On Unix, override $TMPDIR in case the user
-	// has it set to an NFS-mounted directory.
-	dir := ""
-	if runtime.GOOS != "android" && runtime.GOOS != "windows" {
-		dir = "/tmp"
-	}
-	name, err := ioutil.TempDir(dir, "_Go_"+testName)
+	name, err := ioutil.TempDir(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempDir %s: %s", testName, err)
 	}
@@ -310,6 +323,15 @@ func TestReaddirnamesOneAtATime(t *testing.T) {
 	switch runtime.GOOS {
 	case "android":
 		dir = "/system/bin"
+	case "darwin":
+		switch runtime.GOARCH {
+		case "arm", "arm64":
+			wd, err := Getwd()
+			if err != nil {
+				t.Fatal(err)
+			}
+			dir = wd
+		}
 	case "plan9":
 		dir = "/bin"
 	case "windows":
@@ -489,11 +511,35 @@ func TestReaddirStatFailures(t *testing.T) {
 	}
 }
 
+// Readdir on a regular file should fail.
+func TestReaddirOfFile(t *testing.T) {
+	f, err := ioutil.TempFile("", "_Go_ReaddirOfFile")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer Remove(f.Name())
+	f.Write([]byte("foo"))
+	f.Close()
+	reg, err := Open(f.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer reg.Close()
+
+	names, err := reg.Readdirnames(-1)
+	if err == nil {
+		t.Error("Readdirnames succeeded; want non-nil error")
+	}
+	if len(names) > 0 {
+		t.Errorf("unexpected dir names in regular file: %q", names)
+	}
+}
+
 func TestHardLink(t *testing.T) {
-	// Hardlinks are not supported under windows or Plan 9.
 	if runtime.GOOS == "plan9" {
-		return
+		t.Skip("skipping on plan9, hardlinks not supported")
 	}
+	defer chtmpdir(t)()
 	from, to := "hardlinktestfrom", "hardlinktestto"
 	Remove(from) // Just in case.
 	file, err := Create(to)
@@ -508,6 +554,14 @@ func TestHardLink(t *testing.T) {
 	if err != nil {
 		t.Fatalf("link %q, %q failed: %v", to, from, err)
 	}
+
+	none := "hardlinktestnone"
+	err = Link(none, none)
+	// Check the returned error is well-formed.
+	if lerr, ok := err.(*LinkError); !ok || lerr.Error() == "" {
+		t.Errorf("link %q, %q failed to return a valid error", none, none)
+	}
+
 	defer Remove(from)
 	tostat, err := Stat(to)
 	if err != nil {
@@ -522,6 +576,31 @@ func TestHardLink(t *testing.T) {
 	}
 }
 
+// chtmpdir changes the working directory to a new temporary directory and
+// provides a cleanup function. Used when PWD is read-only.
+func chtmpdir(t *testing.T) func() {
+	if runtime.GOOS != "darwin" || (runtime.GOARCH != "arm" && runtime.GOARCH != "arm64") {
+		return func() {} // only needed on darwin/arm{,64}
+	}
+	oldwd, err := Getwd()
+	if err != nil {
+		t.Fatalf("chtmpdir: %v", err)
+	}
+	d, err := ioutil.TempDir("", "test")
+	if err != nil {
+		t.Fatalf("chtmpdir: %v", err)
+	}
+	if err := Chdir(d); err != nil {
+		t.Fatalf("chtmpdir: %v", err)
+	}
+	return func() {
+		if err := Chdir(oldwd); err != nil {
+			t.Fatalf("chtmpdir: %v", err)
+		}
+		RemoveAll(d)
+	}
+}
+
 func TestSymlink(t *testing.T) {
 	switch runtime.GOOS {
 	case "android", "nacl", "plan9":
@@ -531,6 +610,7 @@ func TestSymlink(t *testing.T) {
 			t.Skipf("skipping on %s", runtime.GOOS)
 		}
 	}
+	defer chtmpdir(t)()
 	from, to := "symlinktestfrom", "symlinktestto"
 	Remove(from) // Just in case.
 	file, err := Create(to)
@@ -597,6 +677,7 @@ func TestLongSymlink(t *testing.T) {
 			t.Skipf("skipping on %s", runtime.GOOS)
 		}
 	}
+	defer chtmpdir(t)()
 	s := "0123456789abcdef"
 	// Long, but not too long: a common limit is 255.
 	s = s + s + s + s + s + s + s + s + s + s + s + s + s + s + s
@@ -617,14 +698,18 @@ func TestLongSymlink(t *testing.T) {
 }
 
 func TestRename(t *testing.T) {
+	defer chtmpdir(t)()
 	from, to := "renamefrom", "renameto"
-	Remove(to) // Just in case.
+	// Ensure we are not testing the overwrite case here.
+	Remove(from)
+	Remove(to)
+
 	file, err := Create(from)
 	if err != nil {
-		t.Fatalf("open %q failed: %v", to, err)
+		t.Fatalf("open %q failed: %v", from, err)
 	}
 	if err = file.Close(); err != nil {
-		t.Errorf("close %q failed: %v", to, err)
+		t.Errorf("close %q failed: %v", from, err)
 	}
 	err = Rename(from, to)
 	if err != nil {
@@ -637,6 +722,79 @@ func TestRename(t *testing.T) {
 	}
 }
 
+func TestRenameOverwriteDest(t *testing.T) {
+	if runtime.GOOS == "plan9" {
+		t.Skip("skipping on plan9")
+	}
+	defer chtmpdir(t)()
+	from, to := "renamefrom", "renameto"
+	// Just in case.
+	Remove(from)
+	Remove(to)
+
+	toData := []byte("to")
+	fromData := []byte("from")
+
+	err := ioutil.WriteFile(to, toData, 0777)
+	if err != nil {
+		t.Fatalf("write file %q failed: %v", to, err)
+	}
+
+	err = ioutil.WriteFile(from, fromData, 0777)
+	if err != nil {
+		t.Fatalf("write file %q failed: %v", from, err)
+	}
+	err = Rename(from, to)
+	if err != nil {
+		t.Fatalf("rename %q, %q failed: %v", to, from, err)
+	}
+	defer Remove(to)
+
+	_, err = Stat(from)
+	if err == nil {
+		t.Errorf("from file %q still exists", from)
+	}
+	if err != nil && !IsNotExist(err) {
+		t.Fatalf("stat from: %v", err)
+	}
+	toFi, err := Stat(to)
+	if err != nil {
+		t.Fatalf("stat %q failed: %v", to, err)
+	}
+	if toFi.Size() != int64(len(fromData)) {
+		t.Errorf(`"to" size = %d; want %d (old "from" size)`, toFi.Size(), len(fromData))
+	}
+}
+
+func TestRenameFailed(t *testing.T) {
+	defer chtmpdir(t)()
+	from, to := "renamefrom", "renameto"
+	// Ensure we are not testing the overwrite case here.
+	Remove(from)
+	Remove(to)
+
+	err := Rename(from, to)
+	switch err := err.(type) {
+	case *LinkError:
+		if err.Op != "rename" {
+			t.Errorf("rename %q, %q: err.Op: want %q, got %q", from, to, "rename", err.Op)
+		}
+		if err.Old != from {
+			t.Errorf("rename %q, %q: err.Old: want %q, got %q", from, to, from, err.Old)
+		}
+		if err.New != to {
+			t.Errorf("rename %q, %q: err.New: want %q, got %q", from, to, to, err.New)
+		}
+	case nil:
+		t.Errorf("rename %q, %q: expected error, got nil", from, to)
+
+		// cleanup whatever was placed in "renameto"
+		Remove(to)
+	default:
+		t.Errorf("rename %q, %q: expected %T, got %T %v", from, to, new(LinkError), err, err)
+	}
+}
+
 func exec(t *testing.T, dir, cmd string, args []string, expect string) {
 	r, w, err := Pipe()
 	if err != nil {
@@ -664,18 +822,18 @@ func exec(t *testing.T, dir, cmd string, args []string, expect string) {
 }
 
 func TestStartProcess(t *testing.T) {
-	switch runtime.GOOS {
-	case "android", "nacl":
-		t.Skipf("skipping on %s", runtime.GOOS)
-	}
+	testenv.MustHaveExec(t)
 
 	var dir, cmd string
 	var args []string
-	if runtime.GOOS == "windows" {
+	switch runtime.GOOS {
+	case "android":
+		t.Skip("android doesn't have /bin/pwd")
+	case "windows":
 		cmd = Getenv("COMSPEC")
 		dir = Getenv("SystemRoot")
 		args = []string{"/c", "cd"}
-	} else {
+	default:
 		cmd = "/bin/pwd"
 		dir = "/"
 		args = []string{}
@@ -847,6 +1005,19 @@ func TestChdirAndGetwd(t *testing.T) {
 		dirs = []string{"/", "/system/bin"}
 	case "plan9":
 		dirs = []string{"/", "/usr"}
+	case "darwin":
+		switch runtime.GOARCH {
+		case "arm", "arm64":
+			d1, err := ioutil.TempDir("", "d1")
+			if err != nil {
+				t.Fatalf("TempDir: %v", err)
+			}
+			d2, err := ioutil.TempDir("", "d2")
+			if err != nil {
+				t.Fatalf("TempDir: %v", err)
+			}
+			dirs = []string{d1, d2}
+		}
 	}
 	oldwd := Getenv("PWD")
 	for mode := 0; mode < 2; mode++ {
@@ -892,6 +1063,64 @@ func TestChdirAndGetwd(t *testing.T) {
 	fd.Close()
 }
 
+// Test that Chdir+Getwd is program-wide.
+func TestProgWideChdir(t *testing.T) {
+	const N = 10
+	c := make(chan bool)
+	cpwd := make(chan string)
+	for i := 0; i < N; i++ {
+		go func(i int) {
+			// Lock half the goroutines in their own operating system
+			// thread to exercise more scheduler possibilities.
+			if i%2 == 1 {
+				// On Plan 9, after calling LockOSThread, the goroutines
+				// run on different processes which don't share the working
+				// directory. This used to be an issue because Go expects
+				// the working directory to be program-wide.
+				// See issue 9428.
+				runtime.LockOSThread()
+			}
+			<-c
+			pwd, err := Getwd()
+			if err != nil {
+				t.Errorf("Getwd on goroutine %d: %v", i, err)
+				return
+			}
+			cpwd <- pwd
+		}(i)
+	}
+	oldwd, err := Getwd()
+	if err != nil {
+		t.Fatalf("Getwd: %v", err)
+	}
+	d, err := ioutil.TempDir("", "test")
+	if err != nil {
+		t.Fatalf("TempDir: %v", err)
+	}
+	defer func() {
+		if err := Chdir(oldwd); err != nil {
+			t.Fatalf("Chdir: %v", err)
+		}
+		RemoveAll(d)
+	}()
+	if err := Chdir(d); err != nil {
+		t.Fatalf("Chdir: %v", err)
+	}
+	// OS X sets TMPDIR to a symbolic link.
+	// So we resolve our working directory again before the test.
+	d, err = Getwd()
+	if err != nil {
+		t.Fatalf("Getwd: %v", err)
+	}
+	close(c)
+	for i := 0; i < N; i++ {
+		pwd := <-cpwd
+		if pwd != d {
+			t.Errorf("Getwd returned %q; want %q", pwd, d)
+		}
+	}
+}
+
 func TestSeek(t *testing.T) {
 	f := newFile("TestSeek", t)
 	defer Remove(f.Name())
@@ -920,7 +1149,7 @@ func TestSeek(t *testing.T) {
 		if off != tt.out || err != nil {
 			if e, ok := err.(*PathError); ok && e.Err == syscall.EINVAL && tt.out > 1<<32 {
 				// Reiserfs rejects the big seeks.
-				// http://code.google.com/p/go/issues/detail?id=91
+				// https://golang.org/issue/91
 				break
 			}
 			t.Errorf("#%d: Seek(%v, %v) = %v, %v want %v, nil", i, tt.in, tt.whence, off, err, tt.out)
@@ -1033,14 +1262,35 @@ func run(t *testing.T, cmd []string) string {
 	return output
 }
 
+func testWindowsHostname(t *testing.T) {
+	hostname, err := Hostname()
+	if err != nil {
+		t.Fatal(err)
+	}
+	cmd := osexec.Command("hostname")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("Failed to execute hostname command: %v %s", err, out)
+	}
+	want := strings.Trim(string(out), "\r\n")
+	if hostname != want {
+		t.Fatalf("Hostname() = %q, want %q", hostname, want)
+	}
+}
+
 func TestHostname(t *testing.T) {
 	// There is no other way to fetch hostname on windows, but via winapi.
 	// On Plan 9 it can be taken from #c/sysname as Hostname() does.
 	switch runtime.GOOS {
-	case "android", "nacl", "plan9", "windows":
-		t.Skipf("skipping on %s", runtime.GOOS)
+	case "android", "plan9":
+		t.Skipf("%s doesn't have /bin/hostname", runtime.GOOS)
+	case "windows":
+		testWindowsHostname(t)
+		return
 	}
 
+	testenv.MustHaveExec(t)
+
 	// Check internal Hostname() against the output of /bin/hostname.
 	// Allow that the internal Hostname returns a Fully Qualified Domain Name
 	// and the /bin/hostname only returns the first component
@@ -1115,6 +1365,7 @@ func writeFile(t *testing.T, fname string, flag int, text string) string {
 }
 
 func TestAppend(t *testing.T) {
+	defer chtmpdir(t)()
 	const f = "append.txt"
 	defer Remove(f)
 	s := writeFile(t, f, O_CREATE|O_TRUNC|O_RDWR, "new")
@@ -1178,6 +1429,7 @@ func TestNilProcessStateString(t *testing.T) {
 }
 
 func TestSameFile(t *testing.T) {
+	defer chtmpdir(t)()
 	fa, err := Create("a")
 	if err != nil {
 		t.Fatalf("Create(a): %v", err)
@@ -1297,45 +1549,11 @@ func TestReadAtEOF(t *testing.T) {
 }
 
 func testKillProcess(t *testing.T, processKiller func(p *Process)) {
-	t.Skip("gccgo does not have a go command")
-	switch runtime.GOOS {
-	case "android", "nacl":
-		t.Skipf("skipping on %s", runtime.GOOS)
-	}
-
-	dir, err := ioutil.TempDir("", "go-build")
-	if err != nil {
-		t.Fatalf("Failed to create temp directory: %v", err)
-	}
-	defer RemoveAll(dir)
-
-	src := filepath.Join(dir, "main.go")
-	f, err := Create(src)
-	if err != nil {
-		t.Fatalf("Failed to create %v: %v", src, err)
-	}
-	st := template.Must(template.New("source").Parse(`
-package main
-import "time"
-func main() {
-	time.Sleep(time.Second)
-}
-`))
-	err = st.Execute(f, nil)
-	if err != nil {
-		f.Close()
-		t.Fatalf("Failed to execute template: %v", err)
-	}
-	f.Close()
-
-	exe := filepath.Join(dir, "main.exe")
-	output, err := osexec.Command("go", "build", "-o", exe, src).CombinedOutput()
-	if err != nil {
-		t.Fatalf("Failed to build exe %v: %v %v", exe, err, string(output))
-	}
+	testenv.MustHaveExec(t)
 
-	cmd := osexec.Command(exe)
-	err = cmd.Start()
+	// Re-exec the test binary itself to emulate "sleep 1".
+	cmd := osexec.Command(Args[0], "-test.run", "TestSleep")
+	err := cmd.Start()
 	if err != nil {
 		t.Fatalf("Failed to start test process: %v", err)
 	}
@@ -1349,6 +1567,15 @@ func main() {
 	}
 }
 
+// TestSleep emulates "sleep 1". It is a helper for testKillProcess, so we
+// don't have to rely on an external "sleep" command being available.
+func TestSleep(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping in short mode")
+	}
+	time.Sleep(time.Second)
+}
+
 func TestKillStartProcess(t *testing.T) {
 	testKillProcess(t, func(p *Process) {
 		err := p.Kill()
@@ -1359,14 +1586,13 @@ func TestKillStartProcess(t *testing.T) {
 }
 
 func TestGetppid(t *testing.T) {
-	switch runtime.GOOS {
-	case "nacl":
-		t.Skip("skipping on nacl")
-	case "plan9":
+	if runtime.GOOS == "plan9" {
 		// TODO: golang.org/issue/8206
 		t.Skipf("skipping test on plan9; see issue 8206")
 	}
 
+	testenv.MustHaveExec(t)
+
 	if Getenv("GO_WANT_HELPER_PROCESS") == "1" {
 		fmt.Print(Getppid())
 		Exit(0)
diff --git a/libgo/go/os/os_unix_test.go b/libgo/go/os/os_unix_test.go
index 21d40cc..2adc3b5 100644
--- a/libgo/go/os/os_unix_test.go
+++ b/libgo/go/os/os_unix_test.go
@@ -13,6 +13,10 @@ import (
 	"testing"
 )
 
+func init() {
+	isReadonlyError = func(err error) bool { return err == syscall.EROFS }
+}
+
 func checkUidGid(t *testing.T, path string, uid, gid int) {
 	dir, err := Stat(path)
 	if err != nil {
@@ -28,10 +32,10 @@ func checkUidGid(t *testing.T, path string, uid, gid int) {
 }
 
 func TestChown(t *testing.T) {
-	// Chown is not supported under windows os Plan 9.
+	// Chown is not supported under windows or Plan 9.
 	// Plan9 provides a native ChownPlan9 version instead.
 	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
-		return
+		t.Skipf("%s does not support syscall.Chown", runtime.GOOS)
 	}
 	// Use TempDir() to make sure we're on a local file system,
 	// so that the group ids returned by Getgroups will be allowed
@@ -74,3 +78,109 @@ func TestChown(t *testing.T) {
 		checkUidGid(t, f.Name(), int(sys.Uid), gid)
 	}
 }
+
+func TestFileChown(t *testing.T) {
+	// Fchown is not supported under windows or Plan 9.
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Skipf("%s does not support syscall.Fchown", runtime.GOOS)
+	}
+	// Use TempDir() to make sure we're on a local file system,
+	// so that the group ids returned by Getgroups will be allowed
+	// on the file.  On NFS, the Getgroups groups are
+	// basically useless.
+	f := newFile("TestFileChown", t)
+	defer Remove(f.Name())
+	defer f.Close()
+	dir, err := f.Stat()
+	if err != nil {
+		t.Fatalf("stat %s: %s", f.Name(), err)
+	}
+
+	// Can't change uid unless root, but can try
+	// changing the group id.  First try our current group.
+	gid := Getgid()
+	t.Log("gid:", gid)
+	if err = f.Chown(-1, gid); err != nil {
+		t.Fatalf("fchown %s -1 %d: %s", f.Name(), gid, err)
+	}
+	sys := dir.Sys().(*syscall.Stat_t)
+	checkUidGid(t, f.Name(), int(sys.Uid), gid)
+
+	// Then try all the auxiliary groups.
+	groups, err := Getgroups()
+	if err != nil {
+		t.Fatalf("getgroups: %s", err)
+	}
+	t.Log("groups: ", groups)
+	for _, g := range groups {
+		if err = f.Chown(-1, g); err != nil {
+			t.Fatalf("fchown %s -1 %d: %s", f.Name(), g, err)
+		}
+		checkUidGid(t, f.Name(), int(sys.Uid), g)
+
+		// change back to gid to test fd.Chown
+		if err = f.Chown(-1, gid); err != nil {
+			t.Fatalf("fchown %s -1 %d: %s", f.Name(), gid, err)
+		}
+		checkUidGid(t, f.Name(), int(sys.Uid), gid)
+	}
+}
+
+func TestLchown(t *testing.T) {
+	// Lchown is not supported under windows or Plan 9.
+	if runtime.GOOS == "windows" || runtime.GOOS == "plan9" {
+		t.Skipf("%s does not support syscall.Lchown", runtime.GOOS)
+	}
+	// Use TempDir() to make sure we're on a local file system,
+	// so that the group ids returned by Getgroups will be allowed
+	// on the file.  On NFS, the Getgroups groups are
+	// basically useless.
+	f := newFile("TestLchown", t)
+	defer Remove(f.Name())
+	defer f.Close()
+	dir, err := f.Stat()
+	if err != nil {
+		t.Fatalf("stat %s: %s", f.Name(), err)
+	}
+
+	linkname := f.Name() + "2"
+	if err := Link(f.Name(), linkname); err != nil {
+		t.Fatalf("link %s -> %s: %v", f.Name(), linkname, err)
+	}
+	defer Remove(linkname)
+
+	f2, err := Open(linkname)
+	if err != nil {
+		t.Fatalf("open %s: %v", linkname, err)
+	}
+	defer f2.Close()
+
+	// Can't change uid unless root, but can try
+	// changing the group id.  First try our current group.
+	gid := Getgid()
+	t.Log("gid:", gid)
+	if err = Lchown(linkname, -1, gid); err != nil {
+		t.Fatalf("lchown %s -1 %d: %s", linkname, gid, err)
+	}
+	sys := dir.Sys().(*syscall.Stat_t)
+	checkUidGid(t, linkname, int(sys.Uid), gid)
+
+	// Then try all the auxiliary groups.
+	groups, err := Getgroups()
+	if err != nil {
+		t.Fatalf("getgroups: %s", err)
+	}
+	t.Log("groups: ", groups)
+	for _, g := range groups {
+		if err = Lchown(linkname, -1, g); err != nil {
+			t.Fatalf("lchown %s -1 %d: %s", linkname, g, err)
+		}
+		checkUidGid(t, linkname, int(sys.Uid), g)
+
+		// change back to gid to test fd.Chown
+		if err = f2.Chown(-1, gid); err != nil {
+			t.Fatalf("fchown %s -1 %d: %s", linkname, gid, err)
+		}
+		checkUidGid(t, linkname, int(sys.Uid), gid)
+	}
+}
diff --git a/libgo/go/os/path_plan9.go b/libgo/go/os/path_plan9.go
index 64bad50..b09b53a 100644
--- a/libgo/go/os/path_plan9.go
+++ b/libgo/go/os/path_plan9.go
@@ -9,7 +9,7 @@ const (
 	PathListSeparator = '\000' // OS-specific path list separator
 )
 
-// IsPathSeparator returns true if c is a directory separator character.
+// IsPathSeparator reports whether c is a directory separator character.
 func IsPathSeparator(c uint8) bool {
 	return PathSeparator == c
 }
diff --git a/libgo/go/os/path_test.go b/libgo/go/os/path_test.go
index 6f24a43..f985381 100644
--- a/libgo/go/os/path_test.go
+++ b/libgo/go/os/path_test.go
@@ -13,6 +13,8 @@ import (
 	"testing"
 )
 
+var isReadonlyError = func(error) bool { return false }
+
 func TestMkdirAll(t *testing.T) {
 	tmpDir := TempDir()
 	path := tmpDir + "/_TestMkdirAll_/dir/./dir2"
@@ -205,16 +207,22 @@ func TestMkdirAllAtSlash(t *testing.T) {
 	switch runtime.GOOS {
 	case "android", "plan9", "windows":
 		t.Skipf("skipping on %s", runtime.GOOS)
+	case "darwin":
+		switch runtime.GOARCH {
+		case "arm", "arm64":
+			t.Skipf("skipping on darwin/%s, mkdir returns EPERM", runtime.GOARCH)
+		}
 	}
 	RemoveAll("/_go_os_test")
-	err := MkdirAll("/_go_os_test/dir", 0777)
+	const dir = "/_go_os_test/dir"
+	err := MkdirAll(dir, 0777)
 	if err != nil {
 		pathErr, ok := err.(*PathError)
 		// common for users not to be able to write to /
-		if ok && pathErr.Err == syscall.EACCES {
-			return
+		if ok && (pathErr.Err == syscall.EACCES || isReadonlyError(pathErr.Err)) {
+			t.Skipf("could not create %v: %v", dir, err)
 		}
-		t.Fatalf(`MkdirAll "/_go_os_test/dir": %v`, err)
+		t.Fatalf(`MkdirAll "/_go_os_test/dir": %v, %s`, err, pathErr.Err)
 	}
 	RemoveAll("/_go_os_test")
 }
diff --git a/libgo/go/os/path_unix.go b/libgo/go/os/path_unix.go
index 0211107..36f8e61 100644
--- a/libgo/go/os/path_unix.go
+++ b/libgo/go/os/path_unix.go
@@ -11,7 +11,7 @@ const (
 	PathListSeparator = ':' // OS-specific path list separator
 )
 
-// IsPathSeparator returns true if c is a directory separator character.
+// IsPathSeparator reports whether c is a directory separator character.
 func IsPathSeparator(c uint8) bool {
 	return PathSeparator == c
 }
diff --git a/libgo/go/os/path_windows.go b/libgo/go/os/path_windows.go
index 61f2ca5..c96f137 100644
--- a/libgo/go/os/path_windows.go
+++ b/libgo/go/os/path_windows.go
@@ -9,7 +9,7 @@ const (
 	PathListSeparator = ';'  // OS-specific path list separator
 )
 
-// IsPathSeparator returns true if c is a directory separator character.
+// IsPathSeparator reports whether c is a directory separator character.
 func IsPathSeparator(c uint8) bool {
 	// NOTE: Windows accept / as path separator.
 	return c == '\\' || c == '/'
diff --git a/libgo/go/os/proc.go b/libgo/go/os/proc.go
index 774f099..33a8b26 100644
--- a/libgo/go/os/proc.go
+++ b/libgo/go/os/proc.go
@@ -44,6 +44,14 @@ func Getgroups() ([]int, error) {
 
 // Exit causes the current program to exit with the given status code.
 // Conventionally, code zero indicates success, non-zero an error.
-// The program terminates immediately; deferred functions are
-// not run.
-func Exit(code int) { syscall.Exit(code) }
+// The program terminates immediately; deferred functions are not run.
+func Exit(code int) {
+	if code == 0 {
+		// Give race detector a chance to fail the program.
+		// Racy programs do not have the right to finish successfully.
+		runtime_beforeExit()
+	}
+	syscall.Exit(code)
+}
+
+func runtime_beforeExit() // implemented in runtime
diff --git a/libgo/go/os/signal/signal.go b/libgo/go/os/signal/signal.go
index 3004275..1625786 100644
--- a/libgo/go/os/signal/signal.go
+++ b/libgo/go/os/signal/signal.go
@@ -5,8 +5,6 @@
 // Package signal implements access to incoming signals.
 package signal
 
-// BUG(rsc): This package is not yet implemented on Plan 9.
-
 import (
 	"os"
 	"sync"
@@ -30,9 +28,55 @@ func (h *handler) set(sig int) {
 	h.mask[sig/32] |= 1 << uint(sig&31)
 }
 
+func (h *handler) clear(sig int) {
+	h.mask[sig/32] &^= 1 << uint(sig&31)
+}
+
+// Stop relaying the signals, sigs, to any channels previously registered to
+// receive them and either reset the signal handlers to their original values
+// (action=disableSignal) or ignore the signals (action=ignoreSignal).
+func cancel(sigs []os.Signal, action func(int)) {
+	handlers.Lock()
+	defer handlers.Unlock()
+
+	remove := func(n int) {
+		var zerohandler handler
+
+		for c, h := range handlers.m {
+			if h.want(n) {
+				handlers.ref[n]--
+				h.clear(n)
+				if h.mask == zerohandler.mask {
+					delete(handlers.m, c)
+				}
+			}
+		}
+
+		action(n)
+	}
+
+	if len(sigs) == 0 {
+		for n := 0; n < numSig; n++ {
+			remove(n)
+		}
+	} else {
+		for _, s := range sigs {
+			remove(signum(s))
+		}
+	}
+}
+
+// Ignore causes the provided signals to be ignored. If they are received by
+// the program, nothing will happen. Ignore undoes the effect of any prior
+// calls to Notify for the provided signals.
+// If no signals are provided, all incoming signals will be ignored.
+func Ignore(sig ...os.Signal) {
+	cancel(sig, ignoreSignal)
+}
+
 // Notify causes package signal to relay incoming signals to c.
-// If no signals are listed, all incoming signals will be relayed to c.
-// Otherwise, just the listed signals will.
+// If no signals are provided, all incoming signals will be relayed to c.
+// Otherwise, just the provided signals will.
 //
 // Package signal will not block sending to c: the caller must ensure
 // that c has sufficient buffer space to keep up with the expected
@@ -87,6 +131,13 @@ func Notify(c chan<- os.Signal, sig ...os.Signal) {
 	}
 }
 
+// Reset undoes the effect of any prior calls to Notify for the provided
+// signals.
+// If no signals are provided, all signal handlers will be reset.
+func Reset(sig ...os.Signal) {
+	cancel(sig, disableSignal)
+}
+
 // Stop causes package signal to stop relaying incoming signals to c.
 // It undoes the effect of all prior calls to Notify using c.
 // When Stop returns, it is guaranteed that c will receive no more signals.
diff --git a/libgo/go/os/signal/signal_plan9.go b/libgo/go/os/signal/signal_plan9.go
new file mode 100644
index 0000000..b065ae5
--- /dev/null
+++ b/libgo/go/os/signal/signal_plan9.go
@@ -0,0 +1,60 @@
+// Copyright 2012 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.
+
+package signal
+
+import (
+	"os"
+	"syscall"
+)
+
+var sigtab = make(map[os.Signal]int)
+
+// In sig.s; jumps to runtime.
+func signal_disable(uint32)
+func signal_enable(uint32)
+func signal_ignore(uint32)
+func signal_recv() string
+
+func init() {
+	signal_enable(0) // first call - initialize
+	go loop()
+}
+
+func loop() {
+	for {
+		process(syscall.Note(signal_recv()))
+	}
+}
+
+const numSig = 256
+
+func signum(sig os.Signal) int {
+	switch sig := sig.(type) {
+	case syscall.Note:
+		n, ok := sigtab[sig]
+		if !ok {
+			n = len(sigtab) + 1
+			if n > numSig {
+				return -1
+			}
+			sigtab[sig] = n
+		}
+		return n
+	default:
+		return -1
+	}
+}
+
+func enableSignal(sig int) {
+	signal_enable(uint32(sig))
+}
+
+func disableSignal(sig int) {
+	signal_disable(uint32(sig))
+}
+
+func ignoreSignal(sig int) {
+	signal_ignore(uint32(sig))
+}
diff --git a/libgo/go/os/signal/signal_plan9_test.go b/libgo/go/os/signal/signal_plan9_test.go
new file mode 100644
index 0000000..10bfdc3
--- /dev/null
+++ b/libgo/go/os/signal/signal_plan9_test.go
@@ -0,0 +1,181 @@
+// 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.
+
+package signal
+
+import (
+	"os"
+	"runtime"
+	"syscall"
+	"testing"
+	"time"
+)
+
+func waitSig(t *testing.T, c <-chan os.Signal, sig os.Signal) {
+	select {
+	case s := <-c:
+		if s != sig {
+			t.Fatalf("signal was %v, want %v", s, sig)
+		}
+	case <-time.After(1 * time.Second):
+		t.Fatalf("timeout waiting for %v", sig)
+	}
+}
+
+// Test that basic signal handling works.
+func TestSignal(t *testing.T) {
+	// Ask for hangup
+	c := make(chan os.Signal, 1)
+	Notify(c, syscall.Note("hangup"))
+	defer Stop(c)
+
+	// Send this process a hangup
+	t.Logf("hangup...")
+	postNote(syscall.Getpid(), "hangup")
+	waitSig(t, c, syscall.Note("hangup"))
+
+	// Ask for everything we can get.
+	c1 := make(chan os.Signal, 1)
+	Notify(c1)
+
+	// Send this process an alarm
+	t.Logf("alarm...")
+	postNote(syscall.Getpid(), "alarm")
+	waitSig(t, c1, syscall.Note("alarm"))
+
+	// Send two more hangups, to make sure that
+	// they get delivered on c1 and that not reading
+	// from c does not block everything.
+	t.Logf("hangup...")
+	postNote(syscall.Getpid(), "hangup")
+	waitSig(t, c1, syscall.Note("hangup"))
+	t.Logf("hangup...")
+	postNote(syscall.Getpid(), "hangup")
+	waitSig(t, c1, syscall.Note("hangup"))
+
+	// The first SIGHUP should be waiting for us on c.
+	waitSig(t, c, syscall.Note("hangup"))
+}
+
+func TestStress(t *testing.T) {
+	dur := 3 * time.Second
+	if testing.Short() {
+		dur = 100 * time.Millisecond
+	}
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
+	done := make(chan bool)
+	finished := make(chan bool)
+	go func() {
+		sig := make(chan os.Signal, 1)
+		Notify(sig, syscall.Note("alarm"))
+		defer Stop(sig)
+	Loop:
+		for {
+			select {
+			case <-sig:
+			case <-done:
+				break Loop
+			}
+		}
+		finished <- true
+	}()
+	go func() {
+	Loop:
+		for {
+			select {
+			case <-done:
+				break Loop
+			default:
+				postNote(syscall.Getpid(), "alarm")
+				runtime.Gosched()
+			}
+		}
+		finished <- true
+	}()
+	time.Sleep(dur)
+	close(done)
+	<-finished
+	<-finished
+	// When run with 'go test -cpu=1,2,4' alarm from this test can slip
+	// into subsequent TestSignal() causing failure.
+	// Sleep for a while to reduce the possibility of the failure.
+	time.Sleep(10 * time.Millisecond)
+}
+
+// Test that Stop cancels the channel's registrations.
+func TestStop(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+	sigs := []string{
+		"alarm",
+		"hangup",
+	}
+
+	for _, sig := range sigs {
+		// Send the signal.
+		// If it's alarm, we should not see it.
+		// If it's hangup, maybe we'll die. Let the flag tell us what to do.
+		if sig != "hangup" {
+			postNote(syscall.Getpid(), sig)
+		}
+		time.Sleep(100 * time.Millisecond)
+
+		// Ask for signal
+		c := make(chan os.Signal, 1)
+		Notify(c, syscall.Note(sig))
+		defer Stop(c)
+
+		// Send this process that signal
+		postNote(syscall.Getpid(), sig)
+		waitSig(t, c, syscall.Note(sig))
+
+		Stop(c)
+		select {
+		case s := <-c:
+			t.Fatalf("unexpected signal %v", s)
+		case <-time.After(100 * time.Millisecond):
+			// nothing to read - good
+		}
+
+		// Send the signal.
+		// If it's alarm, we should not see it.
+		// If it's hangup, maybe we'll die. Let the flag tell us what to do.
+		if sig != "hangup" {
+			postNote(syscall.Getpid(), sig)
+		}
+
+		select {
+		case s := <-c:
+			t.Fatalf("unexpected signal %v", s)
+		case <-time.After(100 * time.Millisecond):
+			// nothing to read - good
+		}
+	}
+}
+
+func itoa(val int) string {
+	if val < 0 {
+		return "-" + itoa(-val)
+	}
+	var buf [32]byte // big enough for int64
+	i := len(buf) - 1
+	for val >= 10 {
+		buf[i] = byte(val%10 + '0')
+		i--
+		val /= 10
+	}
+	buf[i] = byte(val + '0')
+	return string(buf[i:])
+}
+
+func postNote(pid int, note string) error {
+	f, err := os.OpenFile("/proc/"+itoa(pid)+"/note", os.O_WRONLY, 0)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	_, err = f.Write([]byte(note))
+	return err
+}
diff --git a/libgo/go/os/signal/signal_stub.go b/libgo/go/os/signal/signal_stub.go
deleted file mode 100644
index d0a6935..0000000
--- a/libgo/go/os/signal/signal_stub.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2012 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.
-
-// +build plan9
-
-package signal
-
-import "os"
-
-const numSig = 0
-
-func signum(sig os.Signal) int { return -1 }
-
-func disableSignal(int) {}
-
-func enableSignal(int) {}
diff --git a/libgo/go/os/signal/signal_test.go b/libgo/go/os/signal/signal_test.go
index 22337a7..a71633c 100644
--- a/libgo/go/os/signal/signal_test.go
+++ b/libgo/go/os/signal/signal_test.go
@@ -109,6 +109,72 @@ func TestStress(t *testing.T) {
 	time.Sleep(10 * time.Millisecond)
 }
 
+func testCancel(t *testing.T, ignore bool) {
+	// Send SIGWINCH. By default this signal should be ignored.
+	syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
+	time.Sleep(100 * time.Millisecond)
+
+	// Ask to be notified on c1 when a SIGWINCH is received.
+	c1 := make(chan os.Signal, 1)
+	Notify(c1, syscall.SIGWINCH)
+	defer Stop(c1)
+
+	// Ask to be notified on c2 when a SIGHUP is received.
+	c2 := make(chan os.Signal, 1)
+	Notify(c2, syscall.SIGHUP)
+	defer Stop(c2)
+
+	// Send this process a SIGWINCH and wait for notification on c1.
+	syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
+	waitSig(t, c1, syscall.SIGWINCH)
+
+	// Send this process a SIGHUP and wait for notification on c2.
+	syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
+	waitSig(t, c2, syscall.SIGHUP)
+
+	// Ignore, or reset the signal handlers for, SIGWINCH and SIGHUP.
+	if ignore {
+		Ignore(syscall.SIGWINCH, syscall.SIGHUP)
+	} else {
+		Reset(syscall.SIGWINCH, syscall.SIGHUP)
+	}
+
+	// Send this process a SIGWINCH. It should be ignored.
+	syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
+
+	// If ignoring, Send this process a SIGHUP. It should be ignored.
+	if ignore {
+		syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
+	}
+
+	select {
+	case s := <-c1:
+		t.Fatalf("unexpected signal %v", s)
+	case <-time.After(100 * time.Millisecond):
+		// nothing to read - good
+	}
+
+	select {
+	case s := <-c2:
+		t.Fatalf("unexpected signal %v", s)
+	case <-time.After(100 * time.Millisecond):
+		// nothing to read - good
+	}
+
+	// Reset the signal handlers for all signals.
+	Reset()
+}
+
+// Test that Reset cancels registration for listed signals on all channels.
+func TestReset(t *testing.T) {
+	testCancel(t, false)
+}
+
+// Test that Ignore cancels registration for listed signals on all channels.
+func TestIgnore(t *testing.T) {
+	testCancel(t, true)
+}
+
 var sendUncaughtSighup = flag.Int("send_uncaught_sighup", 0, "send uncaught SIGHUP during TestStop")
 
 // Test that Stop cancels the channel's registrations.
diff --git a/libgo/go/os/signal/signal_unix.go b/libgo/go/os/signal/signal_unix.go
index 94b8ab3..1bdf1d7 100644
--- a/libgo/go/os/signal/signal_unix.go
+++ b/libgo/go/os/signal/signal_unix.go
@@ -14,6 +14,7 @@ import (
 // In assembly.
 func signal_disable(uint32)
 func signal_enable(uint32)
+func signal_ignore(uint32)
 func signal_recv() uint32
 
 func loop() {
@@ -51,3 +52,7 @@ func enableSignal(sig int) {
 func disableSignal(sig int) {
 	signal_disable(uint32(sig))
 }
+
+func ignoreSignal(sig int) {
+	signal_ignore(uint32(sig))
+}
diff --git a/libgo/go/os/stat_plan9.go b/libgo/go/os/stat_plan9.go
index 25c9a8c..fa4bd83 100644
--- a/libgo/go/os/stat_plan9.go
+++ b/libgo/go/os/stat_plan9.go
@@ -9,6 +9,8 @@ import (
 	"time"
 )
 
+const _BIT16SZ = 2
+
 func sameFile(fs1, fs2 *fileStat) bool {
 	a := fs1.sys.(*syscall.Dir)
 	b := fs2.sys.(*syscall.Dir)
@@ -41,16 +43,14 @@ func fileInfoFromStat(d *syscall.Dir) FileInfo {
 // arg is an open *File or a path string.
 func dirstat(arg interface{}) (*syscall.Dir, error) {
 	var name string
+	var err error
 
-	// This is big enough for most stat messages
-	// and rounded to a multiple of 128 bytes.
-	size := (syscall.STATFIXLEN + 16*4 + 128) &^ 128
+	size := syscall.STATFIXLEN + 16*4
 
 	for i := 0; i < 2; i++ {
-		buf := make([]byte, size)
+		buf := make([]byte, _BIT16SZ+size)
 
 		var n int
-		var err error
 		switch a := arg.(type) {
 		case *File:
 			name = a.name
@@ -61,34 +61,36 @@ func dirstat(arg interface{}) (*syscall.Dir, error) {
 		default:
 			panic("phase error in dirstat")
 		}
-		if err != nil {
+
+		if n < _BIT16SZ {
 			return nil, &PathError{"stat", name, err}
 		}
-		if n < syscall.STATFIXLEN {
-			return nil, &PathError{"stat", name, syscall.ErrShortStat}
-		}
 
 		// Pull the real size out of the stat message.
 		size = int(uint16(buf[0]) | uint16(buf[1])<<8)
 
 		// If the stat message is larger than our buffer we will
 		// go around the loop and allocate one that is big enough.
-		if size > n {
-			continue
+		if size <= n {
+			d, err := syscall.UnmarshalDir(buf[:n])
+			if err != nil {
+				return nil, &PathError{"stat", name, err}
+			}
+			return d, nil
 		}
 
-		d, err := syscall.UnmarshalDir(buf[:n])
-		if err != nil {
-			return nil, &PathError{"stat", name, err}
-		}
-		return d, nil
 	}
-	return nil, &PathError{"stat", name, syscall.ErrBadStat}
+
+	if err == nil {
+		err = syscall.ErrBadStat
+	}
+
+	return nil, &PathError{"stat", name, err}
 }
 
 // Stat returns a FileInfo describing the named file.
 // If there is an error, it will be of type *PathError.
-func Stat(name string) (fi FileInfo, err error) {
+func Stat(name string) (FileInfo, error) {
 	d, err := dirstat(name)
 	if err != nil {
 		return nil, err
@@ -100,7 +102,7 @@ func Stat(name string) (fi FileInfo, err error) {
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func Lstat(name string) (fi FileInfo, err error) {
+func Lstat(name string) (FileInfo, error) {
 	return Stat(name)
 }
 
diff --git a/libgo/go/os/sticky_bsd.go b/libgo/go/os/sticky_bsd.go
new file mode 100644
index 0000000..6b54c75
--- /dev/null
+++ b/libgo/go/os/sticky_bsd.go
@@ -0,0 +1,11 @@
+// Copyright 2014 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.
+
+// +build darwin dragonfly freebsd netbsd openbsd solaris
+
+package os
+
+// According to sticky(8), neither open(2) nor mkdir(2) will create
+// a file with the sticky bit set.
+const supportsCreateWithStickyBit = false
diff --git a/libgo/go/os/sticky_notbsd.go b/libgo/go/os/sticky_notbsd.go
new file mode 100644
index 0000000..834e79b
--- /dev/null
+++ b/libgo/go/os/sticky_notbsd.go
@@ -0,0 +1,14 @@
+// Copyright 2014 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.
+
+// +build !darwin
+// +build !dragonfly
+// +build !freebsd
+// +build !netbsd
+// +build !openbsd
+// +build !solaris
+
+package os
+
+const supportsCreateWithStickyBit = true
diff --git a/libgo/go/os/str.go b/libgo/go/os/str.go
index e3606b6..d3e03e9 100644
--- a/libgo/go/os/str.go
+++ b/libgo/go/os/str.go
@@ -2,21 +2,32 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build plan9
+// Simple converions to avoid depending on strconv.
 
 package os
 
-func itoa(val int) string { // do it here rather than with fmt to avoid dependency
+// Convert integer to decimal string
+func itoa(val int) string {
 	if val < 0 {
-		return "-" + itoa(-val)
+		return "-" + uitoa(uint(-val))
 	}
-	var buf [32]byte // big enough for int64
+	return uitoa(uint(val))
+}
+
+// Convert unsigned integer to decimal string
+func uitoa(val uint) string {
+	if val == 0 { // avoid string allocation
+		return "0"
+	}
+	var buf [20]byte // big enough for 64bit value base 10
 	i := len(buf) - 1
 	for val >= 10 {
-		buf[i] = byte(val%10 + '0')
+		q := val / 10
+		buf[i] = byte('0' + val - q*10)
 		i--
-		val /= 10
+		val = q
 	}
-	buf[i] = byte(val + '0')
+	// val < 10
+	buf[i] = byte('0' + val)
 	return string(buf[i:])
 }
diff --git a/libgo/go/os/types.go b/libgo/go/os/types.go
index 473d431..9d6f8e1 100644
--- a/libgo/go/os/types.go
+++ b/libgo/go/os/types.go
@@ -53,7 +53,7 @@ const (
 	// Mask for the type bits. For regular files, none will be set.
 	ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice
 
-	ModePerm FileMode = 0777 // permission bits
+	ModePerm FileMode = 0777 // Unix permission bits
 )
 
 func (m FileMode) String() string {
diff --git a/libgo/go/os/user/lookup_unix.go b/libgo/go/os/user/lookup_unix.go
index 64f4576..bebb9e8 100644
--- a/libgo/go/os/user/lookup_unix.go
+++ b/libgo/go/os/user/lookup_unix.go
@@ -16,6 +16,7 @@ import (
 )
 
 /*
+#cgo solaris CFLAGS: -D_POSIX_PTHREAD_SEMANTICS
 #include <unistd.h>
 #include <sys/types.h>
 #include <pwd.h>
@@ -23,7 +24,12 @@ import (
 
 static int mygetpwuid_r(int uid, struct passwd *pwd,
 	char *buf, size_t buflen, struct passwd **result) {
- return getpwuid_r(uid, pwd, buf, buflen, result);
+	return getpwuid_r(uid, pwd, buf, buflen, result);
+}
+
+static int mygetpwnam_r(const char *name, struct passwd *pwd,
+	char *buf, size_t buflen, struct passwd **result) {
+	return getpwnam_r(name, pwd, buf, buflen, result);
 }
 */
 
@@ -62,9 +68,9 @@ func lookupUnix(uid int, username string, lookupByName bool) (*User, error) {
 	const bufSize = 1024
 	buf := make([]byte, bufSize)
 	if lookupByName {
-		p := syscall.StringBytePtr(username)
+		nameC := syscall.StringBytePtr(username)
 		syscall.Entersyscall()
-		rv := libc_getpwnam_r(p,
+		rv := libc_getpwnam_r(nameC,
 			&pwd,
 			&buf[0],
 			bufSize,