libgo: update to Go1.12beta2

    
    Reviewed-on: https://go-review.googlesource.com/c/158019

gotools/:
	* Makefile.am (go_cmd_vet_files): Update for Go1.12beta2 release.
	(GOTOOLS_TEST_TIMEOUT): Increase to 600.
	(check-runtime): Export LD_LIBRARY_PATH before computing GOARCH
	and GOOS.
	(check-vet): Copy golang.org/x/tools into check-vet-dir.
	* Makefile.in: Regenerate.

gcc/testsuite/:
	* go.go-torture/execute/names-1.go: Stop using debug/xcoff, which
	is no longer externally visible.

From-SVN: r268084

51 files changed, 1443 insertions, 464 deletions

diff --git a/libgo/go/os/dir_gccgo.go b/libgo/go/os/dir_gccgo.go
index f660646..60f70aa 100644
--- a/libgo/go/os/dir_gccgo.go
+++ b/libgo/go/os/dir_gccgo.go
@@ -16,6 +16,9 @@ import (
 //extern pathconf
 func libc_pathconf(*byte, int) int
 
+//extern fdopendir
+func libc_fdopendir(int32) *syscall.DIR
+
 func clen(n []byte) int {
 	for i := 0; i < len(n); i++ {
 		if n[i] == 0 {
@@ -48,11 +51,11 @@ func (file *File) readdirnames(n int) (names []string, err error) {
 		}
 
 		syscall.Entersyscall()
-		r := libc_opendir(p)
+		r := libc_fdopendir(int32(file.pfd.Sysfd))
 		errno := syscall.GetErrno()
 		syscall.Exitsyscall()
 		if r == nil {
-			return nil, &PathError{"opendir", file.name, errno}
+			return nil, &PathError{"fdopendir", file.name, errno}
 		}
 
 		file.dirinfo = new(dirInfo)
diff --git a/libgo/go/os/dir_ios.go b/libgo/go/os/dir_ios.go
new file mode 100644
index 0000000..8c14d89
--- /dev/null
+++ b/libgo/go/os/dir_ios.go
@@ -0,0 +1,87 @@
+// 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.
+
+// +build darwin
+// +build arm arm64
+
+package os
+
+import (
+	"io"
+	"runtime"
+	"syscall"
+	"unsafe"
+)
+
+// Auxiliary information if the File describes a directory
+type dirInfo struct {
+	dir uintptr // Pointer to DIR structure from dirent.h
+}
+
+func (d *dirInfo) close() {
+	if d.dir == 0 {
+		return
+	}
+	closedir(d.dir)
+	d.dir = 0
+}
+
+func (f *File) readdirnames(n int) (names []string, err error) {
+	if f.dirinfo == nil {
+		dir, call, errno := f.pfd.OpenDir()
+		if errno != nil {
+			return nil, wrapSyscallError(call, errno)
+		}
+		f.dirinfo = &dirInfo{
+			dir: dir,
+		}
+	}
+	d := f.dirinfo
+
+	size := n
+	if size <= 0 {
+		size = 100
+		n = -1
+	}
+
+	names = make([]string, 0, size)
+	var dirent syscall.Dirent
+	var entptr uintptr
+	for len(names) < size {
+		if res := readdir_r(d.dir, uintptr(unsafe.Pointer(&dirent)), uintptr(unsafe.Pointer(&entptr))); res != 0 {
+			return names, wrapSyscallError("readdir", syscall.Errno(res))
+		}
+		if entptr == 0 { // EOF
+			break
+		}
+		if dirent.Ino == 0 {
+			continue
+		}
+		name := (*[len(syscall.Dirent{}.Name)]byte)(unsafe.Pointer(&dirent.Name))[:]
+		for i, c := range name {
+			if c == 0 {
+				name = name[:i]
+				break
+			}
+		}
+		// Check for useless names before allocating a string.
+		if string(name) == "." || string(name) == ".." {
+			continue
+		}
+		names = append(names, string(name))
+		runtime.KeepAlive(f)
+	}
+	if n >= 0 && len(names) == 0 {
+		return names, io.EOF
+	}
+	return names, nil
+}
+
+// Implemented in syscall/syscall_darwin.go.
+
+//go:linkname closedir syscall.closedir
+func closedir(dir uintptr) (err error)
+
+//go:linkname readdir_r syscall.readdir_r
+func readdir_r(dir, entry, result uintptr) (res int)
diff --git a/libgo/go/os/dir_libc64_gccgo.go b/libgo/go/os/dir_libc64_gccgo.go
index 95d4663..dc3ba7f 100644
--- a/libgo/go/os/dir_libc64_gccgo.go
+++ b/libgo/go/os/dir_libc64_gccgo.go
@@ -8,8 +8,5 @@ package os
 
 import "syscall"
 
-//extern opendir64
-func libc_opendir(*byte) *syscall.DIR
-
 //extern closedir64
 func libc_closedir(*syscall.DIR) int
diff --git a/libgo/go/os/dir_libc_gccgo.go b/libgo/go/os/dir_libc_gccgo.go
index 1ee253c..b46eb4c 100644
--- a/libgo/go/os/dir_libc_gccgo.go
+++ b/libgo/go/os/dir_libc_gccgo.go
@@ -8,8 +8,5 @@ package os
 
 import "syscall"
 
-//extern opendir
-func libc_opendir(*byte) *syscall.DIR
-
 //extern closedir
 func libc_closedir(*syscall.DIR) int
diff --git a/libgo/go/os/dir_unix.go b/libgo/go/os/dir_unix.go
deleted file mode 100644
index edfc9ea..0000000
--- a/libgo/go/os/dir_unix.go
+++ /dev/null
@@ -1,38 +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.
-
-// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
-
-package os
-
-import (
-	"io"
-)
-
-func (f *File) readdir(n int) (fi []FileInfo, err error) {
-	dirname := f.name
-	if dirname == "" {
-		dirname = "."
-	}
-	names, err := f.Readdirnames(n)
-	fi = make([]FileInfo, 0, len(names))
-	for _, filename := range names {
-		fip, lerr := lstat(dirname + "/" + filename)
-		if IsNotExist(lerr) {
-			// File disappeared between readdir + stat.
-			// Just treat it as if it didn't exist.
-			continue
-		}
-		if lerr != nil {
-			return fi, lerr
-		}
-		fi = append(fi, fip)
-	}
-	if len(fi) == 0 && err == nil && n > 0 {
-		// Per File.Readdir, the slice must be non-empty or err
-		// must be non-nil if n > 0.
-		err = io.EOF
-	}
-	return fi, err
-}
diff --git a/libgo/go/os/env_unix_test.go b/libgo/go/os/env_unix_test.go
index f7b67eb..89430b3 100644
--- a/libgo/go/os/env_unix_test.go
+++ b/libgo/go/os/env_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package os_test
 
diff --git a/libgo/go/os/error_posix.go b/libgo/go/os/error_posix.go
index 3c81b41..0478ba6 100644
--- a/libgo/go/os/error_posix.go
+++ b/libgo/go/os/error_posix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
 
 package os
 
diff --git a/libgo/go/os/error_unix_test.go b/libgo/go/os/error_unix_test.go
index 8db9867..c47af56 100644
--- a/libgo/go/os/error_unix_test.go
+++ b/libgo/go/os/error_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package os_test
 
diff --git a/libgo/go/os/example_test.go b/libgo/go/os/example_test.go
index e21415a..8b6566e 100644
--- a/libgo/go/os/example_test.go
+++ b/libgo/go/os/example_test.go
@@ -55,6 +55,7 @@ func ExampleFileMode() {
 		log.Fatal(err)
 	}
 
+	fmt.Printf("permissions: %#o\n", fi.Mode().Perm()) // 0400, 0777, etc.
 	switch mode := fi.Mode(); {
 	case mode.IsRegular():
 		fmt.Println("regular file")
@@ -70,38 +71,35 @@ func ExampleFileMode() {
 func ExampleIsNotExist() {
 	filename := "a-nonexistent-file"
 	if _, err := os.Stat(filename); os.IsNotExist(err) {
-		fmt.Printf("file does not exist")
+		fmt.Println("file does not exist")
 	}
 	// Output:
 	// file does not exist
 }
 
-func init() {
-	os.Setenv("USER", "gopher")
-	os.Setenv("HOME", "/usr/gopher")
-	os.Unsetenv("GOPATH")
-}
-
 func ExampleExpand() {
 	mapper := func(placeholderName string) string {
 		switch placeholderName {
 		case "DAY_PART":
 			return "morning"
-		case "USER":
+		case "NAME":
 			return "Gopher"
 		}
 
 		return ""
 	}
 
-	fmt.Println(os.Expand("Good ${DAY_PART}, $USER!", mapper))
+	fmt.Println(os.Expand("Good ${DAY_PART}, $NAME!", mapper))
 
 	// Output:
 	// Good morning, Gopher!
 }
 
 func ExampleExpandEnv() {
-	fmt.Println(os.ExpandEnv("$USER lives in ${HOME}."))
+	os.Setenv("NAME", "gopher")
+	os.Setenv("BURROW", "/usr/gopher")
+
+	fmt.Println(os.ExpandEnv("$NAME lives in ${BURROW}."))
 
 	// Output:
 	// gopher lives in /usr/gopher.
@@ -117,16 +115,24 @@ func ExampleLookupEnv() {
 		}
 	}
 
-	show("USER")
-	show("GOPATH")
+	os.Setenv("SOME_KEY", "value")
+	os.Setenv("EMPTY_KEY", "")
+
+	show("SOME_KEY")
+	show("EMPTY_KEY")
+	show("MISSING_KEY")
 
 	// Output:
-	// USER=gopher
-	// GOPATH not set
+	// SOME_KEY=value
+	// EMPTY_KEY=
+	// MISSING_KEY not set
 }
 
 func ExampleGetenv() {
-	fmt.Printf("%s lives in %s.\n", os.Getenv("USER"), os.Getenv("HOME"))
+	os.Setenv("NAME", "gopher")
+	os.Setenv("BURROW", "/usr/gopher")
+
+	fmt.Printf("%s lives in %s.\n", os.Getenv("NAME"), os.Getenv("BURROW"))
 
 	// Output:
 	// gopher lives in /usr/gopher.
diff --git a/libgo/go/os/exec/exec.go b/libgo/go/os/exec/exec.go
index 88b0a91..1aa3ab9 100644
--- a/libgo/go/os/exec/exec.go
+++ b/libgo/go/os/exec/exec.go
@@ -152,6 +152,15 @@ type Cmd struct {
 // followed by the elements of arg, so arg should not include the
 // command name itself. For example, Command("echo", "hello").
 // Args[0] is always name, not the possibly resolved Path.
+//
+// On Windows, processes receive the whole command line as a single string
+// and do their own parsing. Command combines and quotes Args into a command
+// line string with an algorithm compatible with applications using
+// CommandLineToArgvW (which is the most common way). Notable exceptions are
+// msiexec.exe and cmd.exe (and thus, all batch files), which have a different
+// unquoting algorithm. In these or other similar cases, you can do the
+// quoting yourself and provide the full command line in SysProcAttr.CmdLine,
+// leaving Args empty.
 func Command(name string, arg ...string) *Cmd {
 	cmd := &Cmd{
 		Path: name,
diff --git a/libgo/go/os/exec/exec_posix_test.go b/libgo/go/os/exec/exec_posix_test.go
index 865b6c3..46799cd 100644
--- a/libgo/go/os/exec/exec_posix_test.go
+++ b/libgo/go/os/exec/exec_posix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package exec_test
 
diff --git a/libgo/go/os/exec/exec_test.go b/libgo/go/os/exec/exec_test.go
index 1e38285..b7cc9da 100644
--- a/libgo/go/os/exec/exec_test.go
+++ b/libgo/go/os/exec/exec_test.go
@@ -172,6 +172,58 @@ func TestExitStatus(t *testing.T) {
 	}
 }
 
+func TestExitCode(t *testing.T) {
+	// Test that exit code are returned correctly
+	cmd := helperCommand(t, "exit", "42")
+	cmd.Run()
+	want := 42
+	if runtime.GOOS == "plan9" {
+		want = 1
+	}
+	got := cmd.ProcessState.ExitCode()
+	if want != got {
+		t.Errorf("ExitCode got %d, want %d", got, want)
+	}
+
+	cmd = helperCommand(t, "/no-exist-executable")
+	cmd.Run()
+	want = 2
+	if runtime.GOOS == "plan9" {
+		want = 1
+	}
+	got = cmd.ProcessState.ExitCode()
+	if want != got {
+		t.Errorf("ExitCode got %d, want %d", got, want)
+	}
+
+	cmd = helperCommand(t, "exit", "255")
+	cmd.Run()
+	want = 255
+	if runtime.GOOS == "plan9" {
+		want = 1
+	}
+	got = cmd.ProcessState.ExitCode()
+	if want != got {
+		t.Errorf("ExitCode got %d, want %d", got, want)
+	}
+
+	cmd = helperCommand(t, "cat")
+	cmd.Run()
+	want = 0
+	got = cmd.ProcessState.ExitCode()
+	if want != got {
+		t.Errorf("ExitCode got %d, want %d", got, want)
+	}
+
+	// Test when command does not call Run().
+	cmd = helperCommand(t, "cat")
+	want = -1
+	got = cmd.ProcessState.ExitCode()
+	if want != got {
+		t.Errorf("ExitCode got %d, want %d", got, want)
+	}
+}
+
 func TestPipes(t *testing.T) {
 	check := func(what string, err error) {
 		if err != nil {
@@ -411,7 +463,7 @@ func basefds() uintptr {
 	// The poll (epoll/kqueue) descriptor can be numerically
 	// either between stderr and the testlog-fd, or after
 	// testlog-fd.
-	if poll.PollDescriptor() == n {
+	if poll.IsPollDescriptor(n) {
 		n++
 	}
 	for _, arg := range os.Args {
@@ -424,7 +476,7 @@ func basefds() uintptr {
 
 func closeUnexpectedFds(t *testing.T, m string) {
 	for fd := basefds(); fd <= 101; fd++ {
-		if fd == poll.PollDescriptor() {
+		if poll.IsPollDescriptor(fd) {
 			continue
 		}
 		err := os.NewFile(fd, "").Close()
@@ -686,6 +738,8 @@ func TestHelperProcess(*testing.T) {
 		ofcmd = "fstat"
 	case "plan9":
 		ofcmd = "/bin/cat"
+	case "aix":
+		ofcmd = "procfiles"
 	}
 
 	args := os.Args
@@ -789,7 +843,7 @@ func TestHelperProcess(*testing.T) {
 			// Now verify that there are no other open fds.
 			var files []*os.File
 			for wantfd := basefds() + 1; wantfd <= 100; wantfd++ {
-				if wantfd == poll.PollDescriptor() {
+				if poll.IsPollDescriptor(wantfd) {
 					continue
 				}
 				f, err := os.Open(os.Args[0])
@@ -803,6 +857,8 @@ func TestHelperProcess(*testing.T) {
 					switch runtime.GOOS {
 					case "plan9":
 						args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())}
+					case "aix":
+						args = []string{fmt.Sprint(os.Getpid())}
 					default:
 						args = []string{"-p", fmt.Sprint(os.Getpid())}
 					}
diff --git a/libgo/go/os/exec/lp_unix_test.go b/libgo/go/os/exec/lp_unix_test.go
index d467acf..e4656ca 100644
--- a/libgo/go/os/exec/lp_unix_test.go
+++ b/libgo/go/os/exec/lp_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package exec
 
diff --git a/libgo/go/os/exec_plan9.go b/libgo/go/os/exec_plan9.go
index 6b4d28c..bab16cc 100644
--- a/libgo/go/os/exec_plan9.go
+++ b/libgo/go/os/exec_plan9.go
@@ -136,3 +136,13 @@ func (p *ProcessState) String() string {
 	}
 	return "exit status: " + p.status.Msg
 }
+
+// ExitCode returns the exit code of the exited process, or -1
+// if the process hasn't exited or was terminated by a signal.
+func (p *ProcessState) ExitCode() int {
+	// return -1 if the process hasn't started.
+	if p == nil {
+		return -1
+	}
+	return p.status.ExitStatus()
+}
diff --git a/libgo/go/os/exec_posix.go b/libgo/go/os/exec_posix.go
index dbbb5df..4c82612 100644
--- a/libgo/go/os/exec_posix.go
+++ b/libgo/go/os/exec_posix.go
@@ -10,10 +10,11 @@ import (
 	"syscall"
 )
 
-// The only signal values guaranteed to be present in the os package
-// on all systems are Interrupt (send the process an interrupt) and
-// Kill (force the process to exit). Interrupt is not implemented on
-// Windows; using it with os.Process.Signal will return an error.
+// The only signal values guaranteed to be present in the os package on all
+// systems are os.Interrupt (send the process an interrupt) and os.Kill (force
+// the process to exit). On Windows, sending os.Interrupt to a process with
+// os.Process.Signal is not implemented; it will return an error instead of
+// sending a signal.
 var (
 	Interrupt Signal = syscall.SIGINT
 	Kill      Signal = syscall.SIGKILL
@@ -106,3 +107,13 @@ func (p *ProcessState) String() string {
 	}
 	return res
 }
+
+// ExitCode returns the exit code of the exited process, or -1
+// if the process hasn't exited or was terminated by a signal.
+func (p *ProcessState) ExitCode() int {
+	// return -1 if the process hasn't started.
+	if p == nil {
+		return -1
+	}
+	return p.status.ExitStatus()
+}
diff --git a/libgo/go/os/exec_windows.go b/libgo/go/os/exec_windows.go
index d5d553a..38293a0 100644
--- a/libgo/go/os/exec_windows.go
+++ b/libgo/go/os/exec_windows.go
@@ -38,7 +38,8 @@ func (p *Process) wait() (ps *ProcessState, err error) {
 	// NOTE(brainman): It seems that sometimes process is not dead
 	// when WaitForSingleObject returns. But we do not know any
 	// other way to wait for it. Sleeping for a while seems to do
-	// the trick sometimes. So we will sleep and smell the roses.
+	// the trick sometimes.
+	// See https://golang.org/issue/25965 for details.
 	defer time.Sleep(5 * time.Millisecond)
 	defer p.Release()
 	return &ProcessState{p.Pid, syscall.WaitStatus{ExitCode: ec}, &u}, nil
diff --git a/libgo/go/os/executable_test.go b/libgo/go/os/executable_test.go
index 4a9a883..d513c87 100644
--- a/libgo/go/os/executable_test.go
+++ b/libgo/go/os/executable_test.go
@@ -36,8 +36,8 @@ func TestExecutable(t *testing.T) {
 	// forge argv[0] for child, so that we can verify we could correctly
 	// get real path of the executable without influenced by argv[0].
 	cmd.Args = []string{"-", "-test.run=XXXX"}
-	if runtime.GOOS == "openbsd" {
-		// OpenBSD relies on argv[0]
+	if runtime.GOOS == "openbsd" || runtime.GOOS == "aix" {
+		// OpenBSD and AIX rely on argv[0]
 		cmd.Args[0] = fn
 	}
 	cmd.Env = append(os.Environ(), fmt.Sprintf("%s=1", executable_EnvVar))
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go
index cba70d7..fdead63 100644
--- a/libgo/go/os/file.go
+++ b/libgo/go/os/file.go
@@ -73,7 +73,7 @@ const (
 	O_CREATE int = syscall.O_CREAT  // create a new file if none exists.
 	O_EXCL   int = syscall.O_EXCL   // used with O_CREATE, file must not exist.
 	O_SYNC   int = syscall.O_SYNC   // open for synchronous I/O.
-	O_TRUNC  int = syscall.O_TRUNC  // if possible, truncate file when opened.
+	O_TRUNC  int = syscall.O_TRUNC  // truncate regular writable file when opened.
 )
 
 // Seek whence values.
@@ -381,6 +381,31 @@ func UserCacheDir() (string, error) {
 	return dir, nil
 }
 
+// UserHomeDir returns the current user's home directory.
+//
+// On Unix, including macOS, it returns the $HOME environment variable.
+// On Windows, it returns %USERPROFILE%.
+// On Plan 9, it returns the $home environment variable.
+func UserHomeDir() (string, error) {
+	env, enverr := "HOME", "$HOME"
+	switch runtime.GOOS {
+	case "windows":
+		env, enverr = "USERPROFILE", "%userprofile%"
+	case "plan9":
+		env, enverr = "home", "$home"
+	case "nacl", "android":
+		return "/", nil
+	case "darwin":
+		if runtime.GOARCH == "arm" || runtime.GOARCH == "arm64" {
+			return "/", nil
+		}
+	}
+	if v := Getenv(env); v != "" {
+		return v, nil
+	}
+	return "", errors.New(enverr + " is not defined")
+}
+
 // Chmod changes the mode of the named file to mode.
 // If the file is a symbolic link, it changes the mode of the link's target.
 // If there is an error, it will be of type *PathError.
@@ -448,3 +473,12 @@ func (f *File) SetReadDeadline(t time.Time) error {
 func (f *File) SetWriteDeadline(t time.Time) error {
 	return f.setWriteDeadline(t)
 }
+
+// SyscallConn returns a raw file.
+// This implements the syscall.Conn interface.
+func (f *File) SyscallConn() (syscall.RawConn, error) {
+	if err := f.checkValid("SyscallConn"); err != nil {
+		return nil, err
+	}
+	return newRawConn(f)
+}
diff --git a/libgo/go/os/file_plan9.go b/libgo/go/os/file_plan9.go
index 2c74403..3fa12e6 100644
--- a/libgo/go/os/file_plan9.go
+++ b/libgo/go/os/file_plan9.go
@@ -534,3 +534,21 @@ func (f *File) checkValid(op string) error {
 	}
 	return nil
 }
+
+type rawConn struct{}
+
+func (c *rawConn) Control(f func(uintptr)) error {
+	return syscall.EPLAN9
+}
+
+func (c *rawConn) Read(f func(uintptr) bool) error {
+	return syscall.EPLAN9
+}
+
+func (c *rawConn) Write(f func(uintptr) bool) error {
+	return syscall.EPLAN9
+}
+
+func newRawConn(file *File) (*rawConn, error) {
+	return nil, syscall.EPLAN9
+}
diff --git a/libgo/go/os/file_posix.go b/libgo/go/os/file_posix.go
index 9bd1cc7..1c0de5c 100644
--- a/libgo/go/os/file_posix.go
+++ b/libgo/go/os/file_posix.go
@@ -7,6 +7,7 @@
 package os
 
 import (
+	"runtime"
 	"syscall"
 	"time"
 )
@@ -20,7 +21,7 @@ func Readlink(name string) (string, error) {
 		b := make([]byte, len)
 		n, e := fixCount(syscall.Readlink(fixLongPath(name), b))
 		// buffer too small
-		if e == syscall.ERANGE {
+		if runtime.GOOS == "aix" && e == syscall.ERANGE {
 			continue
 		}
 		if e != nil {
diff --git a/libgo/go/os/file_unix.go b/libgo/go/os/file_unix.go
index b2aea33..e9ac774 100644
--- a/libgo/go/os/file_unix.go
+++ b/libgo/go/os/file_unix.go
@@ -9,6 +9,7 @@ package os
 import (
 	"internal/poll"
 	"internal/syscall/unix"
+	"io"
 	"runtime"
 	"syscall"
 )
@@ -116,23 +117,39 @@ func newFile(fd uintptr, name string, kind newFileKind) *File {
 
 	pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock
 
-	// Don't try to use kqueue with regular files on FreeBSD.
-	// It crashes the system unpredictably while running all.bash.
-	// Issue 19093.
 	// If the caller passed a non-blocking filedes (kindNonBlock),
 	// we assume they know what they are doing so we allow it to be
 	// used with kqueue.
-	if runtime.GOOS == "freebsd" && kind == kindOpenFile {
-		pollable = false
-	}
-
-	// On Darwin, kqueue does not work properly with fifos:
-	// closing the last writer does not cause a kqueue event
-	// for any readers. See issue #24164.
-	if runtime.GOOS == "darwin" && kind == kindOpenFile {
+	if kind == kindOpenFile {
 		var st syscall.Stat_t
-		if err := syscall.Fstat(fdi, &st); err == nil && st.Mode&syscall.S_IFMT == syscall.S_IFIFO {
+		switch runtime.GOOS {
+		case "freebsd":
+			// On FreeBSD before 10.4 it used to crash the
+			// system unpredictably while running all.bash.
+			// When we stop supporting FreeBSD 10 we can merge
+			// this into the dragonfly/netbsd/openbsd case.
+			// Issue 27619.
 			pollable = false
+
+		case "dragonfly", "netbsd", "openbsd":
+			// Don't try to use kqueue with regular files on *BSDs.
+			// On FreeBSD a regular file is always
+			// reported as ready for writing.
+			// On Dragonfly, NetBSD and OpenBSD the fd is signaled
+			// only once as ready (both read and write).
+			// Issue 19093.
+			if err := syscall.Fstat(fdi, &st); err == nil && st.Mode&syscall.S_IFMT == syscall.S_IFREG {
+				pollable = false
+			}
+
+		case "darwin":
+			// In addition to the behavior described above for regular files,
+			// on Darwin, kqueue does not work properly with fifos:
+			// closing the last writer does not cause a kqueue event
+			// for any readers. See issue #24164.
+			if err := syscall.Fstat(fdi, &st); err == nil && (st.Mode&syscall.S_IFMT == syscall.S_IFIFO || st.Mode&syscall.S_IFMT == syscall.S_IFREG) {
+				pollable = false
+			}
 		}
 	}
 
@@ -230,22 +247,22 @@ func (file *file) close() error {
 		return syscall.EINVAL
 	}
 	var err error
-	if e := file.pfd.Close(); e != nil {
-		if e == poll.ErrFileClosing {
-			e = ErrClosed
-		}
-		err = &PathError{"close", file.name, e}
-	}
-
 	if file.dirinfo != nil {
 		syscall.Entersyscall()
 		i := libc_closedir(file.dirinfo.dir)
 		errno := syscall.GetErrno()
 		syscall.Exitsyscall()
 		file.dirinfo = nil
-		if i < 0 && err == nil {
+		if i < 0 && errno != 0 {
 			err = &PathError{"closedir", file.name, errno}
 		}
+	} else {
+		if e := file.pfd.Close(); e != nil {
+			if e == poll.ErrFileClosing {
+				e = ErrClosed
+			}
+			err = &PathError{"close", file.name, e}
+		}
 	}
 
 	// no need for a finalizer anymore
@@ -368,3 +385,30 @@ func Symlink(oldname, newname string) error {
 	}
 	return nil
 }
+
+func (f *File) readdir(n int) (fi []FileInfo, err error) {
+	dirname := f.name
+	if dirname == "" {
+		dirname = "."
+	}
+	names, err := f.Readdirnames(n)
+	fi = make([]FileInfo, 0, len(names))
+	for _, filename := range names {
+		fip, lerr := lstat(dirname + "/" + filename)
+		if IsNotExist(lerr) {
+			// File disappeared between readdir + stat.
+			// Just treat it as if it didn't exist.
+			continue
+		}
+		if lerr != nil {
+			return fi, lerr
+		}
+		fi = append(fi, fip)
+	}
+	if len(fi) == 0 && err == nil && n > 0 {
+		// Per File.Readdir, the slice must be non-empty or err
+		// must be non-nil if n > 0.
+		err = io.EOF
+	}
+	return fi, err
+}
diff --git a/libgo/go/os/os_test.go b/libgo/go/os/os_test.go
index 5a77d66..98eba89 100644
--- a/libgo/go/os/os_test.go
+++ b/libgo/go/os/os_test.go
@@ -176,7 +176,6 @@ func TestStatError(t *testing.T) {
 	defer chtmpdir(t)()
 
 	path := "no-such-file"
-	Remove(path) // Just in case
 
 	fi, err := Stat(path)
 	if err == nil {
@@ -192,12 +191,10 @@ func TestStatError(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
 	link := "symlink"
-	Remove(link) // Just in case
 	err = Symlink(path, link)
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer Remove(link)
 
 	fi, err = Stat(link)
 	if err == nil {
@@ -267,7 +264,7 @@ func TestRead0(t *testing.T) {
 	}
 }
 
-// Reading a closed file should should return ErrClosed error
+// Reading a closed file should return ErrClosed error
 func TestReadClosed(t *testing.T) {
 	path := sfdir + "/" + sfname
 	file, err := Open(path)
@@ -686,12 +683,10 @@ func TestHardLink(t *testing.T) {
 
 	defer chtmpdir(t)()
 	from, to := "hardlinktestfrom", "hardlinktestto"
-	Remove(from) // Just in case.
 	file, err := Create(to)
 	if err != nil {
 		t.Fatalf("open %q failed: %v", to, err)
 	}
-	defer Remove(to)
 	if err = file.Close(); err != nil {
 		t.Errorf("close %q failed: %v", to, err)
 	}
@@ -707,7 +702,6 @@ func TestHardLink(t *testing.T) {
 		t.Errorf("link %q, %q failed to return a valid error", none, none)
 	}
 
-	defer Remove(from)
 	tostat, err := Stat(to)
 	if err != nil {
 		t.Fatalf("stat %q failed: %v", to, err)
@@ -743,11 +737,8 @@ 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.
+// provides a cleanup function.
 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)
@@ -772,12 +763,10 @@ func TestSymlink(t *testing.T) {
 
 	defer chtmpdir(t)()
 	from, to := "symlinktestfrom", "symlinktestto"
-	Remove(from) // Just in case.
 	file, err := Create(to)
 	if err != nil {
 		t.Fatalf("Create(%q) failed: %v", to, err)
 	}
-	defer Remove(to)
 	if err = file.Close(); err != nil {
 		t.Errorf("Close(%q) failed: %v", to, err)
 	}
@@ -785,7 +774,6 @@ func TestSymlink(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Symlink(%q, %q) failed: %v", to, from, err)
 	}
-	defer Remove(from)
 	tostat, err := Lstat(to)
 	if err != nil {
 		t.Fatalf("Lstat(%q) failed: %v", to, err)
@@ -839,12 +827,10 @@ func TestLongSymlink(t *testing.T) {
 	// 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
 	from := "longsymlinktestfrom"
-	Remove(from) // Just in case.
 	err := Symlink(s, from)
 	if err != nil {
 		t.Fatalf("symlink %q, %q failed: %v", s, from, err)
 	}
-	defer Remove(from)
 	r, err := Readlink(from)
 	if err != nil {
 		t.Fatalf("readlink %q failed: %v", from, err)
@@ -857,9 +843,6 @@ func TestLongSymlink(t *testing.T) {
 func TestRename(t *testing.T) {
 	defer chtmpdir(t)()
 	from, to := "renamefrom", "renameto"
-	// Ensure we are not testing the overwrite case here.
-	Remove(from)
-	Remove(to)
 
 	file, err := Create(from)
 	if err != nil {
@@ -872,7 +855,6 @@ func TestRename(t *testing.T) {
 	if err != nil {
 		t.Fatalf("rename %q, %q failed: %v", to, from, err)
 	}
-	defer Remove(to)
 	_, err = Stat(to)
 	if err != nil {
 		t.Errorf("stat %q failed: %v", to, err)
@@ -882,9 +864,6 @@ func TestRename(t *testing.T) {
 func TestRenameOverwriteDest(t *testing.T) {
 	defer chtmpdir(t)()
 	from, to := "renamefrom", "renameto"
-	// Just in case.
-	Remove(from)
-	Remove(to)
 
 	toData := []byte("to")
 	fromData := []byte("from")
@@ -902,7 +881,6 @@ func TestRenameOverwriteDest(t *testing.T) {
 	if err != nil {
 		t.Fatalf("rename %q, %q failed: %v", to, from, err)
 	}
-	defer Remove(to)
 
 	_, err = Stat(from)
 	if err == nil {
@@ -923,9 +901,6 @@ func TestRenameOverwriteDest(t *testing.T) {
 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) {
@@ -941,9 +916,6 @@ func TestRenameFailed(t *testing.T) {
 		}
 	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)
 	}
@@ -954,7 +926,6 @@ func TestRenameNotExisting(t *testing.T) {
 	from, to := "doesnt-exist", "dest"
 
 	Mkdir(to, 0777)
-	defer Remove(to)
 
 	if err := Rename(from, to); !IsNotExist(err) {
 		t.Errorf("Rename(%q, %q) = %v; want an IsNotExist error", from, to, err)
@@ -965,12 +936,8 @@ func TestRenameToDirFailed(t *testing.T) {
 	defer chtmpdir(t)()
 	from, to := "renamefrom", "renameto"
 
-	Remove(from)
-	Remove(to)
 	Mkdir(from, 0777)
 	Mkdir(to, 0777)
-	defer Remove(from)
-	defer Remove(to)
 
 	err := Rename(from, to)
 	switch err := err.(type) {
@@ -986,9 +953,6 @@ func TestRenameToDirFailed(t *testing.T) {
 		}
 	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)
 	}
@@ -1483,7 +1447,7 @@ func TestOpenNoName(t *testing.T) {
 	}
 }
 
-func runBinHostname(t *testing.T, argv []string) string {
+func runBinHostname(t *testing.T) string {
 	// Run /bin/hostname and collect output.
 	r, w, err := Pipe()
 	if err != nil {
@@ -1491,6 +1455,10 @@ func runBinHostname(t *testing.T, argv []string) string {
 	}
 	defer r.Close()
 	const path = "/bin/hostname"
+	argv := []string{"hostname"}
+	if runtime.GOOS == "aix" {
+		argv = []string{"hostname", "-s"}
+	}
 	p, err := StartProcess(path, argv, &ProcAttr{Files: []*File{nil, w, Stderr}})
 	if err != nil {
 		if _, err := Stat(path); IsNotExist(err) {
@@ -1561,12 +1529,7 @@ func TestHostname(t *testing.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
-	var want string
-	if runtime.GOOS == "aix" {
-		want = runBinHostname(t, []string{"hostname", "-s"})
-	} else {
-		want = runBinHostname(t, []string{"hostname"})
-	}
+	want := runBinHostname(t)
 	if hostname != want {
 		i := strings.Index(hostname, ".")
 		if i < 0 || hostname[0:i] != want {
@@ -1701,7 +1664,6 @@ 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")
 	if s != "new" {
 		t.Fatalf("writeFile: have %q want %q", s, "new")
@@ -1768,13 +1730,11 @@ func TestSameFile(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Create(a): %v", err)
 	}
-	defer Remove(fa.Name())
 	fa.Close()
 	fb, err := Create("b")
 	if err != nil {
 		t.Fatalf("Create(b): %v", err)
 	}
-	defer Remove(fb.Name())
 	fb.Close()
 
 	ia1, err := Stat("a")
@@ -2336,3 +2296,20 @@ func TestDoubleCloseError(t *testing.T) {
 		t.Logf("second close returned expected error %q", err)
 	}
 }
+
+func TestUserHomeDir(t *testing.T) {
+	dir, err := UserHomeDir()
+	if dir == "" && err == nil {
+		t.Fatal("UserHomeDir returned an empty string but no error")
+	}
+	if err != nil {
+		t.Skipf("UserHomeDir failed: %v", err)
+	}
+	fi, err := Stat(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !fi.IsDir() {
+		t.Fatalf("dir %s is not directory; type = %v", dir, fi.Mode())
+	}
+}
diff --git a/libgo/go/os/os_unix_test.go b/libgo/go/os/os_unix_test.go
index 54f121e..2aa930e 100644
--- a/libgo/go/os/os_unix_test.go
+++ b/libgo/go/os/os_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package os_test
 
@@ -22,6 +22,9 @@ func init() {
 	isReadonlyError = func(err error) bool { return err == syscall.EROFS }
 }
 
+// For TestRawConnReadWrite.
+type syscallDescriptor = int
+
 func checkUidGid(t *testing.T, path string, uid, gid int) {
 	dir, err := Lstat(path)
 	if err != nil {
@@ -234,7 +237,7 @@ func newFileTest(t *testing.T, blocking bool) {
 	}
 	defer syscall.Close(p[1])
 
-	// Set the the read-side to non-blocking.
+	// Set the read-side to non-blocking.
 	if !blocking {
 		if err := syscall.SetNonblock(p[0], true); err != nil {
 			syscall.Close(p[0])
diff --git a/libgo/go/os/path.go b/libgo/go/os/path.go
index cdfbc18..30cc6c8 100644
--- a/libgo/go/os/path.go
+++ b/libgo/go/os/path.go
@@ -5,7 +5,6 @@
 package os
 
 import (
-	"io"
 	"syscall"
 )
 
@@ -59,100 +58,13 @@ func MkdirAll(path string, perm FileMode) error {
 	return nil
 }
 
-// RemoveAll removes path and any children it contains.
-// It removes everything it can but returns the first error
-// it encounters. If the path does not exist, RemoveAll
-// returns nil (no error).
-func RemoveAll(path string) error {
-	// Simple case: if Remove works, we're done.
-	err := Remove(path)
-	if err == nil || IsNotExist(err) {
-		return nil
+// endsWithDot reports whether the final component of path is ".".
+func endsWithDot(path string) bool {
+	if path == "." {
+		return true
 	}
-
-	// Otherwise, is this a directory we need to recurse into?
-	dir, serr := Lstat(path)
-	if serr != nil {
-		if serr, ok := serr.(*PathError); ok && (IsNotExist(serr.Err) || serr.Err == syscall.ENOTDIR) {
-			return nil
-		}
-		return serr
-	}
-	if !dir.IsDir() {
-		// Not a directory; return the error from Remove.
-		return err
-	}
-
-	// Remove contents & return first error.
-	err = nil
-	for {
-		fd, err := Open(path)
-		if err != nil {
-			if IsNotExist(err) {
-				// Already deleted by someone else.
-				return nil
-			}
-			return err
-		}
-
-		const request = 1024
-		names, err1 := fd.Readdirnames(request)
-
-		// Removing files from the directory may have caused
-		// the OS to reshuffle it. Simply calling Readdirnames
-		// again may skip some entries. The only reliable way
-		// to avoid this is to close and re-open the
-		// directory. See issue 20841.
-		fd.Close()
-
-		for _, name := range names {
-			err1 := RemoveAll(path + string(PathSeparator) + name)
-			if err == nil {
-				err = err1
-			}
-		}
-
-		if err1 == io.EOF {
-			break
-		}
-		// If Readdirnames returned an error, use it.
-		if err == nil {
-			err = err1
-		}
-		if len(names) == 0 {
-			break
-		}
-
-		// We don't want to re-open unnecessarily, so if we
-		// got fewer than request names from Readdirnames, try
-		// simply removing the directory now. If that
-		// succeeds, we are done.
-		if len(names) < request {
-			err1 := Remove(path)
-			if err1 == nil || IsNotExist(err1) {
-				return nil
-			}
-
-			if err != nil {
-				// We got some error removing the
-				// directory contents, and since we
-				// read fewer names than we requested
-				// there probably aren't more files to
-				// remove. Don't loop around to read
-				// the directory again. We'll probably
-				// just get the same error.
-				return err
-			}
-		}
-	}
-
-	// Remove directory.
-	err1 := Remove(path)
-	if err1 == nil || IsNotExist(err1) {
-		return nil
-	}
-	if err == nil {
-		err = err1
+	if len(path) >= 2 && path[len(path)-1] == '.' && IsPathSeparator(path[len(path)-2]) {
+		return true
 	}
-	return err
+	return false
 }
diff --git a/libgo/go/os/path_test.go b/libgo/go/os/path_test.go
index f58c7e7..6cb25bc 100644
--- a/libgo/go/os/path_test.go
+++ b/libgo/go/os/path_test.go
@@ -5,7 +5,6 @@
 package os_test
 
 import (
-	"fmt"
 	"internal/testenv"
 	"io/ioutil"
 	. "os"
@@ -76,130 +75,6 @@ func TestMkdirAll(t *testing.T) {
 	}
 }
 
-func TestRemoveAll(t *testing.T) {
-	tmpDir := TempDir()
-	// Work directory.
-	path := tmpDir + "/_TestRemoveAll_"
-	fpath := path + "/file"
-	dpath := path + "/dir"
-
-	// Make directory with 1 file and remove.
-	if err := MkdirAll(path, 0777); err != nil {
-		t.Fatalf("MkdirAll %q: %s", path, err)
-	}
-	fd, err := Create(fpath)
-	if err != nil {
-		t.Fatalf("create %q: %s", fpath, err)
-	}
-	fd.Close()
-	if err = RemoveAll(path); err != nil {
-		t.Fatalf("RemoveAll %q (first): %s", path, err)
-	}
-	if _, err = Lstat(path); err == nil {
-		t.Fatalf("Lstat %q succeeded after RemoveAll (first)", path)
-	}
-
-	// Make directory with file and subdirectory and remove.
-	if err = MkdirAll(dpath, 0777); err != nil {
-		t.Fatalf("MkdirAll %q: %s", dpath, err)
-	}
-	fd, err = Create(fpath)
-	if err != nil {
-		t.Fatalf("create %q: %s", fpath, err)
-	}
-	fd.Close()
-	fd, err = Create(dpath + "/file")
-	if err != nil {
-		t.Fatalf("create %q: %s", fpath, err)
-	}
-	fd.Close()
-	if err = RemoveAll(path); err != nil {
-		t.Fatalf("RemoveAll %q (second): %s", path, err)
-	}
-	if _, err := Lstat(path); err == nil {
-		t.Fatalf("Lstat %q succeeded after RemoveAll (second)", path)
-	}
-
-	// Determine if we should run the following test.
-	testit := true
-	if runtime.GOOS == "windows" {
-		// Chmod is not supported under windows.
-		testit = false
-	} else {
-		// Test fails as root.
-		testit = Getuid() != 0
-	}
-	if testit {
-		// Make directory with file and subdirectory and trigger error.
-		if err = MkdirAll(dpath, 0777); err != nil {
-			t.Fatalf("MkdirAll %q: %s", dpath, err)
-		}
-
-		for _, s := range []string{fpath, dpath + "/file1", path + "/zzz"} {
-			fd, err = Create(s)
-			if err != nil {
-				t.Fatalf("create %q: %s", s, err)
-			}
-			fd.Close()
-		}
-		if err = Chmod(dpath, 0); err != nil {
-			t.Fatalf("Chmod %q 0: %s", dpath, err)
-		}
-
-		// No error checking here: either RemoveAll
-		// will or won't be able to remove dpath;
-		// either way we want to see if it removes fpath
-		// and path/zzz. Reasons why RemoveAll might
-		// succeed in removing dpath as well include:
-		//	* running as root
-		//	* running on a file system without permissions (FAT)
-		RemoveAll(path)
-		Chmod(dpath, 0777)
-
-		for _, s := range []string{fpath, path + "/zzz"} {
-			if _, err = Lstat(s); err == nil {
-				t.Fatalf("Lstat %q succeeded after partial RemoveAll", s)
-			}
-		}
-	}
-	if err = RemoveAll(path); err != nil {
-		t.Fatalf("RemoveAll %q after partial RemoveAll: %s", path, err)
-	}
-	if _, err = Lstat(path); err == nil {
-		t.Fatalf("Lstat %q succeeded after RemoveAll (final)", path)
-	}
-}
-
-// Test RemoveAll on a large directory.
-func TestRemoveAllLarge(t *testing.T) {
-	if testing.Short() {
-		t.Skip("skipping in short mode")
-	}
-
-	tmpDir := TempDir()
-	// Work directory.
-	path := tmpDir + "/_TestRemoveAllLarge_"
-
-	// Make directory with 1000 files and remove.
-	if err := MkdirAll(path, 0777); err != nil {
-		t.Fatalf("MkdirAll %q: %s", path, err)
-	}
-	for i := 0; i < 1000; i++ {
-		fpath := fmt.Sprintf("%s/file%d", path, i)
-		fd, err := Create(fpath)
-		if err != nil {
-			t.Fatalf("create %q: %s", fpath, err)
-		}
-		fd.Close()
-	}
-	if err := RemoveAll(path); err != nil {
-		t.Fatalf("RemoveAll %q: %s", path, err)
-	}
-	if _, err := Lstat(path); err == nil {
-		t.Fatalf("Lstat %q succeeded after RemoveAll", path)
-	}
-}
-
 func TestMkdirAllWithSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
diff --git a/libgo/go/os/path_unix.go b/libgo/go/os/path_unix.go
index 3cb0e3a..be373a5 100644
--- a/libgo/go/os/path_unix.go
+++ b/libgo/go/os/path_unix.go
@@ -16,7 +16,7 @@ func IsPathSeparator(c uint8) bool {
 	return PathSeparator == c
 }
 
-// basename removes trailing slashes and the leading directory name from path name
+// basename removes trailing slashes and the leading directory name from path name.
 func basename(name string) string {
 	i := len(name) - 1
 	// Remove trailing slashes
@@ -34,6 +34,32 @@ func basename(name string) string {
 	return name
 }
 
+// splitPath returns the base name and parent directory.
+func splitPath(path string) (string, string) {
+	// if no better parent is found, the path is relative from "here"
+	dirname := "."
+	// if no slashes in path, base is path
+	basename := path
+
+	i := len(path) - 1
+
+	// Remove trailing slashes
+	for ; i > 0 && path[i] == '/'; i-- {
+		path = path[:i]
+	}
+
+	// Remove leading directory path
+	for i--; i >= 0; i-- {
+		if path[i] == '/' {
+			dirname = path[:i+1]
+			basename = path[i+1:]
+			break
+		}
+	}
+
+	return dirname, basename
+}
+
 func fixRootDirectory(p string) string {
 	return p
 }
diff --git a/libgo/go/os/path_windows_test.go b/libgo/go/os/path_windows_test.go
index 00a3e63..f1745ad 100644
--- a/libgo/go/os/path_windows_test.go
+++ b/libgo/go/os/path_windows_test.go
@@ -38,10 +38,10 @@ func TestFixLongPath(t *testing.T) {
 		{`\\?\c:\long\foo.txt`, `\\?\c:\long\foo.txt`},
 		{`\\?\c:\long/foo.txt`, `\\?\c:\long/foo.txt`},
 	} {
-		in := strings.Replace(test.in, "long", veryLong, -1)
-		want := strings.Replace(test.want, "long", veryLong, -1)
+		in := strings.ReplaceAll(test.in, "long", veryLong)
+		want := strings.ReplaceAll(test.want, "long", veryLong)
 		if got := os.FixLongPath(in); got != want {
-			got = strings.Replace(got, veryLong, "long", -1)
+			got = strings.ReplaceAll(got, veryLong, "long")
 			t.Errorf("fixLongPath(%q) = %q; want %q", test.in, got, test.want)
 		}
 	}
diff --git a/libgo/go/os/pipe_test.go b/libgo/go/os/pipe_test.go
index 59d31e5..779b2bd 100644
--- a/libgo/go/os/pipe_test.go
+++ b/libgo/go/os/pipe_test.go
@@ -131,7 +131,7 @@ func testClosedPipeRace(t *testing.T, read bool) {
 	if !read {
 		// Get the amount we have to write to overload a pipe
 		// with no reader.
-		limit = 65537
+		limit = 131073
 		if b, err := ioutil.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
 			if i, err := strconv.Atoi(strings.TrimSpace(string(b))); err == nil {
 				limit = i + 1
diff --git a/libgo/go/os/rawconn.go b/libgo/go/os/rawconn.go
new file mode 100644
index 0000000..9e11cda
--- /dev/null
+++ b/libgo/go/os/rawconn.go
@@ -0,0 +1,47 @@
+// Copyright 2018 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 os
+
+import (
+	"runtime"
+)
+
+// rawConn implements syscall.RawConn.
+type rawConn struct {
+	file *File
+}
+
+func (c *rawConn) Control(f func(uintptr)) error {
+	if err := c.file.checkValid("SyscallConn.Control"); err != nil {
+		return err
+	}
+	err := c.file.pfd.RawControl(f)
+	runtime.KeepAlive(c.file)
+	return err
+}
+
+func (c *rawConn) Read(f func(uintptr) bool) error {
+	if err := c.file.checkValid("SyscallConn.Read"); err != nil {
+		return err
+	}
+	err := c.file.pfd.RawRead(f)
+	runtime.KeepAlive(c.file)
+	return err
+}
+
+func (c *rawConn) Write(f func(uintptr) bool) error {
+	if err := c.file.checkValid("SyscallConn.Write"); err != nil {
+		return err
+	}
+	err := c.file.pfd.RawWrite(f)
+	runtime.KeepAlive(c.file)
+	return err
+}
+
+func newRawConn(file *File) (*rawConn, error) {
+	return &rawConn{file: file}, nil
+}
diff --git a/libgo/go/os/rawconn_test.go b/libgo/go/os/rawconn_test.go
new file mode 100644
index 0000000..820150d
--- /dev/null
+++ b/libgo/go/os/rawconn_test.go
@@ -0,0 +1,65 @@
+// Copyright 2018 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.
+
+// Test use of raw connections.
+// +build !plan9,!nacl,!js
+
+package os_test
+
+import (
+	"os"
+	"syscall"
+	"testing"
+)
+
+func TestRawConnReadWrite(t *testing.T) {
+	t.Parallel()
+
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+	defer w.Close()
+
+	rconn, err := r.SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+	wconn, err := w.SyscallConn()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var operr error
+	err = wconn.Write(func(s uintptr) bool {
+		_, operr = syscall.Write(syscallDescriptor(s), []byte{'b'})
+		return operr != syscall.EAGAIN
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if operr != nil {
+		t.Fatal(err)
+	}
+
+	var n int
+	buf := make([]byte, 1)
+	err = rconn.Read(func(s uintptr) bool {
+		n, operr = syscall.Read(syscallDescriptor(s), buf)
+		return operr != syscall.EAGAIN
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if operr != nil {
+		t.Fatal(operr)
+	}
+	if n != 1 {
+		t.Errorf("read %d bytes, expected 1", n)
+	}
+	if buf[0] != 'b' {
+		t.Errorf("read %q, expected %q", buf, "b")
+	}
+}
diff --git a/libgo/go/os/removeall_at.go b/libgo/go/os/removeall_at.go
new file mode 100644
index 0000000..f0fed6d
--- /dev/null
+++ b/libgo/go/os/removeall_at.go
@@ -0,0 +1,138 @@
+// Copyright 2018 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 aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package os
+
+import (
+	"internal/syscall/unix"
+	"io"
+	"syscall"
+)
+
+func RemoveAll(path string) error {
+	if path == "" {
+		// fail silently to retain compatibility with previous behavior
+		// of RemoveAll. See issue 28830.
+		return nil
+	}
+
+	// The rmdir system call does not permit removing ".",
+	// so we don't permit it either.
+	if endsWithDot(path) {
+		return &PathError{"RemoveAll", path, syscall.EINVAL}
+	}
+
+	// Simple case: if Remove works, we're done.
+	err := Remove(path)
+	if err == nil || IsNotExist(err) {
+		return nil
+	}
+
+	// RemoveAll recurses by deleting the path base from
+	// its parent directory
+	parentDir, base := splitPath(path)
+
+	parent, err := Open(parentDir)
+	if IsNotExist(err) {
+		// If parent does not exist, base cannot exist. Fail silently
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	defer parent.Close()
+
+	return removeAllFrom(parent, base)
+}
+
+func removeAllFrom(parent *File, path string) error {
+	parentFd := int(parent.Fd())
+	// Simple case: if Unlink (aka remove) works, we're done.
+	err := unix.Unlinkat(parentFd, path, 0)
+	if err == nil || IsNotExist(err) {
+		return nil
+	}
+
+	// If not a "is directory" error, we have a problem
+	if err != syscall.EISDIR && err != syscall.EPERM {
+		return err
+	}
+
+	// Is this a directory we need to recurse into?
+	var statInfo syscall.Stat_t
+	statErr := unix.Fstatat(parentFd, path, &statInfo, unix.AT_SYMLINK_NOFOLLOW)
+	if statErr != nil {
+		return statErr
+	}
+	if statInfo.Mode&syscall.S_IFMT != syscall.S_IFDIR {
+		// Not a directory; return the error from the Remove
+		return err
+	}
+
+	// Remove the directory's entries
+	var recurseErr error
+	for {
+		const request = 1024
+
+		// Open the directory to recurse into
+		file, err := openFdAt(parentFd, path)
+		if err != nil {
+			if IsNotExist(err) {
+				return nil
+			}
+			return err
+		}
+
+		names, readErr := file.Readdirnames(request)
+		// Errors other than EOF should stop us from continuing
+		if readErr != nil && readErr != io.EOF {
+			file.Close()
+			if IsNotExist(readErr) {
+				return nil
+			}
+			return readErr
+		}
+
+		for _, name := range names {
+			err := removeAllFrom(file, name)
+			if err != nil {
+				recurseErr = err
+			}
+		}
+
+		// Removing files from the directory may have caused
+		// the OS to reshuffle it. Simply calling Readdirnames
+		// again may skip some entries. The only reliable way
+		// to avoid this is to close and re-open the
+		// directory. See issue 20841.
+		file.Close()
+
+		// Finish when the end of the directory is reached
+		if len(names) < request {
+			break
+		}
+	}
+
+	// Remove the directory itself
+	unlinkError := unix.Unlinkat(parentFd, path, unix.AT_REMOVEDIR)
+	if unlinkError == nil || IsNotExist(unlinkError) {
+		return nil
+	}
+
+	if recurseErr != nil {
+		return recurseErr
+	}
+	return unlinkError
+}
+
+func openFdAt(fd int, path string) (*File, error) {
+	fd, err := unix.Openat(fd, path, O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewFile(uintptr(fd), path), nil
+}
diff --git a/libgo/go/os/removeall_noat.go b/libgo/go/os/removeall_noat.go
new file mode 100644
index 0000000..80527e2
--- /dev/null
+++ b/libgo/go/os/removeall_noat.go
@@ -0,0 +1,123 @@
+// Copyright 2018 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 !aix,!darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris
+
+package os
+
+import (
+	"io"
+	"syscall"
+)
+
+// RemoveAll removes path and any children it contains.
+// It removes everything it can but returns the first error
+// it encounters. If the path does not exist, RemoveAll
+// returns nil (no error).
+func RemoveAll(path string) error {
+	if path == "" {
+		// fail silently to retain compatibility with previous behavior
+		// of RemoveAll. See issue 28830.
+		return nil
+	}
+
+	// The rmdir system call permits removing "." on Plan 9,
+	// so we don't permit it to remain consistent with the
+	// "at" implementation of RemoveAll.
+	if endsWithDot(path) {
+		return &PathError{"RemoveAll", path, syscall.EINVAL}
+	}
+
+	// Simple case: if Remove works, we're done.
+	err := Remove(path)
+	if err == nil || IsNotExist(err) {
+		return nil
+	}
+
+	// Otherwise, is this a directory we need to recurse into?
+	dir, serr := Lstat(path)
+	if serr != nil {
+		if serr, ok := serr.(*PathError); ok && (IsNotExist(serr.Err) || serr.Err == syscall.ENOTDIR) {
+			return nil
+		}
+		return serr
+	}
+	if !dir.IsDir() {
+		// Not a directory; return the error from Remove.
+		return err
+	}
+
+	// Remove contents & return first error.
+	err = nil
+	for {
+		fd, err := Open(path)
+		if err != nil {
+			if IsNotExist(err) {
+				// Already deleted by someone else.
+				return nil
+			}
+			return err
+		}
+
+		const request = 1024
+		names, err1 := fd.Readdirnames(request)
+
+		// Removing files from the directory may have caused
+		// the OS to reshuffle it. Simply calling Readdirnames
+		// again may skip some entries. The only reliable way
+		// to avoid this is to close and re-open the
+		// directory. See issue 20841.
+		fd.Close()
+
+		for _, name := range names {
+			err1 := RemoveAll(path + string(PathSeparator) + name)
+			if err == nil {
+				err = err1
+			}
+		}
+
+		if err1 == io.EOF {
+			break
+		}
+		// If Readdirnames returned an error, use it.
+		if err == nil {
+			err = err1
+		}
+		if len(names) == 0 {
+			break
+		}
+
+		// We don't want to re-open unnecessarily, so if we
+		// got fewer than request names from Readdirnames, try
+		// simply removing the directory now. If that
+		// succeeds, we are done.
+		if len(names) < request {
+			err1 := Remove(path)
+			if err1 == nil || IsNotExist(err1) {
+				return nil
+			}
+
+			if err != nil {
+				// We got some error removing the
+				// directory contents, and since we
+				// read fewer names than we requested
+				// there probably aren't more files to
+				// remove. Don't loop around to read
+				// the directory again. We'll probably
+				// just get the same error.
+				return err
+			}
+		}
+	}
+
+	// Remove directory.
+	err1 := Remove(path)
+	if err1 == nil || IsNotExist(err1) {
+		return nil
+	}
+	if err == nil {
+		err = err1
+	}
+	return err
+}
diff --git a/libgo/go/os/removeall_test.go b/libgo/go/os/removeall_test.go
new file mode 100644
index 0000000..0f7dce0
--- /dev/null
+++ b/libgo/go/os/removeall_test.go
@@ -0,0 +1,294 @@
+// Copyright 2018 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 os_test
+
+import (
+	"fmt"
+	"io/ioutil"
+	. "os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestRemoveAll(t *testing.T) {
+	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	if err := RemoveAll(""); err != nil {
+		t.Errorf("RemoveAll(\"\"): %v; want nil", err)
+	}
+
+	file := filepath.Join(tmpDir, "file")
+	path := filepath.Join(tmpDir, "_TestRemoveAll_")
+	fpath := filepath.Join(path, "file")
+	dpath := filepath.Join(path, "dir")
+
+	// Make a regular file and remove
+	fd, err := Create(file)
+	if err != nil {
+		t.Fatalf("create %q: %s", file, err)
+	}
+	fd.Close()
+	if err = RemoveAll(file); err != nil {
+		t.Fatalf("RemoveAll %q (first): %s", file, err)
+	}
+	if _, err = Lstat(file); err == nil {
+		t.Fatalf("Lstat %q succeeded after RemoveAll (first)", file)
+	}
+
+	// Make directory with 1 file and remove.
+	if err := MkdirAll(path, 0777); err != nil {
+		t.Fatalf("MkdirAll %q: %s", path, err)
+	}
+	fd, err = Create(fpath)
+	if err != nil {
+		t.Fatalf("create %q: %s", fpath, err)
+	}
+	fd.Close()
+	if err = RemoveAll(path); err != nil {
+		t.Fatalf("RemoveAll %q (second): %s", path, err)
+	}
+	if _, err = Lstat(path); err == nil {
+		t.Fatalf("Lstat %q succeeded after RemoveAll (second)", path)
+	}
+
+	// Make directory with file and subdirectory and remove.
+	if err = MkdirAll(dpath, 0777); err != nil {
+		t.Fatalf("MkdirAll %q: %s", dpath, err)
+	}
+	fd, err = Create(fpath)
+	if err != nil {
+		t.Fatalf("create %q: %s", fpath, err)
+	}
+	fd.Close()
+	fd, err = Create(dpath + "/file")
+	if err != nil {
+		t.Fatalf("create %q: %s", fpath, err)
+	}
+	fd.Close()
+	if err = RemoveAll(path); err != nil {
+		t.Fatalf("RemoveAll %q (third): %s", path, err)
+	}
+	if _, err := Lstat(path); err == nil {
+		t.Fatalf("Lstat %q succeeded after RemoveAll (third)", path)
+	}
+
+	// Determine if we should run the following test.
+	testit := true
+	if runtime.GOOS == "windows" {
+		// Chmod is not supported under windows.
+		testit = false
+	} else {
+		// Test fails as root.
+		testit = Getuid() != 0
+	}
+	if testit {
+		// Make directory with file and subdirectory and trigger error.
+		if err = MkdirAll(dpath, 0777); err != nil {
+			t.Fatalf("MkdirAll %q: %s", dpath, err)
+		}
+
+		for _, s := range []string{fpath, dpath + "/file1", path + "/zzz"} {
+			fd, err = Create(s)
+			if err != nil {
+				t.Fatalf("create %q: %s", s, err)
+			}
+			fd.Close()
+		}
+		if err = Chmod(dpath, 0); err != nil {
+			t.Fatalf("Chmod %q 0: %s", dpath, err)
+		}
+
+		// No error checking here: either RemoveAll
+		// will or won't be able to remove dpath;
+		// either way we want to see if it removes fpath
+		// and path/zzz. Reasons why RemoveAll might
+		// succeed in removing dpath as well include:
+		//	* running as root
+		//	* running on a file system without permissions (FAT)
+		RemoveAll(path)
+		Chmod(dpath, 0777)
+
+		for _, s := range []string{fpath, path + "/zzz"} {
+			if _, err = Lstat(s); err == nil {
+				t.Fatalf("Lstat %q succeeded after partial RemoveAll", s)
+			}
+		}
+	}
+	if err = RemoveAll(path); err != nil {
+		t.Fatalf("RemoveAll %q after partial RemoveAll: %s", path, err)
+	}
+	if _, err = Lstat(path); err == nil {
+		t.Fatalf("Lstat %q succeeded after RemoveAll (final)", path)
+	}
+}
+
+// Test RemoveAll on a large directory.
+func TestRemoveAllLarge(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	path := filepath.Join(tmpDir, "_TestRemoveAllLarge_")
+
+	// Make directory with 1000 files and remove.
+	if err := MkdirAll(path, 0777); err != nil {
+		t.Fatalf("MkdirAll %q: %s", path, err)
+	}
+	for i := 0; i < 1000; i++ {
+		fpath := fmt.Sprintf("%s/file%d", path, i)
+		fd, err := Create(fpath)
+		if err != nil {
+			t.Fatalf("create %q: %s", fpath, err)
+		}
+		fd.Close()
+	}
+	if err := RemoveAll(path); err != nil {
+		t.Fatalf("RemoveAll %q: %s", path, err)
+	}
+	if _, err := Lstat(path); err == nil {
+		t.Fatalf("Lstat %q succeeded after RemoveAll", path)
+	}
+}
+
+func TestRemoveAllLongPath(t *testing.T) {
+	switch runtime.GOOS {
+	case "aix", "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
+		break
+	default:
+		t.Skip("skipping for not implemented platforms")
+	}
+
+	prevDir, err := Getwd()
+	if err != nil {
+		t.Fatalf("Could not get wd: %s", err)
+	}
+
+	startPath, err := ioutil.TempDir("", "TestRemoveAllLongPath-")
+	if err != nil {
+		t.Fatalf("Could not create TempDir: %s", err)
+	}
+	defer RemoveAll(startPath)
+
+	err = Chdir(startPath)
+	if err != nil {
+		t.Fatalf("Could not chdir %s: %s", startPath, err)
+	}
+
+	// Removing paths with over 4096 chars commonly fails
+	for i := 0; i < 41; i++ {
+		name := strings.Repeat("a", 100)
+
+		err = Mkdir(name, 0755)
+		if err != nil {
+			t.Fatalf("Could not mkdir %s: %s", name, err)
+		}
+
+		err = Chdir(name)
+		if err != nil {
+			t.Fatalf("Could not chdir %s: %s", name, err)
+		}
+	}
+
+	err = Chdir(prevDir)
+	if err != nil {
+		t.Fatalf("Could not chdir %s: %s", prevDir, err)
+	}
+
+	err = RemoveAll(startPath)
+	if err != nil {
+		t.Errorf("RemoveAll could not remove long file path %s: %s", startPath, err)
+	}
+}
+
+func TestRemoveAllDot(t *testing.T) {
+	prevDir, err := Getwd()
+	if err != nil {
+		t.Fatalf("Could not get wd: %s", err)
+	}
+	tempDir, err := ioutil.TempDir("", "TestRemoveAllDot-")
+	if err != nil {
+		t.Fatalf("Could not create TempDir: %s", err)
+	}
+	defer RemoveAll(tempDir)
+
+	err = Chdir(tempDir)
+	if err != nil {
+		t.Fatalf("Could not chdir to tempdir: %s", err)
+	}
+
+	err = RemoveAll(".")
+	if err == nil {
+		t.Errorf("RemoveAll succeed to remove .")
+	}
+
+	err = Chdir(prevDir)
+	if err != nil {
+		t.Fatalf("Could not chdir %s: %s", prevDir, err)
+	}
+}
+
+func TestRemoveAllDotDot(t *testing.T) {
+	t.Parallel()
+
+	tempDir, err := ioutil.TempDir("", "TestRemoveAllDotDot-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tempDir)
+
+	subdir := filepath.Join(tempDir, "x")
+	subsubdir := filepath.Join(subdir, "y")
+	if err := MkdirAll(subsubdir, 0777); err != nil {
+		t.Fatal(err)
+	}
+	if err := RemoveAll(filepath.Join(subsubdir, "..")); err != nil {
+		t.Error(err)
+	}
+	for _, dir := range []string{subsubdir, subdir} {
+		if _, err := Stat(dir); err == nil {
+			t.Errorf("%s: exists after RemoveAll", dir)
+		}
+	}
+}
+
+// Issue #29178.
+func TestRemoveReadOnlyDir(t *testing.T) {
+	t.Parallel()
+
+	tempDir, err := ioutil.TempDir("", "TestRemoveReadOnlyDir-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tempDir)
+
+	subdir := filepath.Join(tempDir, "x")
+	if err := Mkdir(subdir, 0); err != nil {
+		t.Fatal(err)
+	}
+
+	// If an error occurs make it more likely that removing the
+	// temporary directory will succeed.
+	defer Chmod(subdir, 0777)
+
+	if err := RemoveAll(subdir); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, err := Stat(subdir); err == nil {
+		t.Error("subdirectory was not removed")
+	}
+}
diff --git a/libgo/go/os/signal/internal/pty/pty.go b/libgo/go/os/signal/internal/pty/pty.go
index e52d19a..a82cf05 100644
--- a/libgo/go/os/signal/internal/pty/pty.go
+++ b/libgo/go/os/signal/internal/pty/pty.go
@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // +build aix darwin dragonfly freebsd linux,!android netbsd openbsd solaris
+// +build cgo
 
 // Package pty is a simple pseudo-terminal package for Unix systems,
 // implemented by calling C functions via cgo.
diff --git a/libgo/go/os/signal/signal_cgo_test.go b/libgo/go/os/signal/signal_cgo_test.go
index 16aeea8..3c23090 100644
--- a/libgo/go/os/signal/signal_cgo_test.go
+++ b/libgo/go/os/signal/signal_cgo_test.go
@@ -22,6 +22,7 @@ import (
 	"os/signal/internal/pty"
 	"strconv"
 	"strings"
+	"sync"
 	"syscall"
 	"testing"
 	"time"
@@ -113,7 +114,11 @@ func TestTerminalSignal(t *testing.T) {
 	const prompt = "prompt> "
 
 	// Read data from master in the background.
+	var wg sync.WaitGroup
+	wg.Add(1)
+	defer wg.Wait()
 	go func() {
+		defer wg.Done()
 		input := bufio.NewReader(master)
 		var line, handled []byte
 		for {
diff --git a/libgo/go/os/stat_aix.go b/libgo/go/os/stat_aix.go
index 265761f..5301827 100644
--- a/libgo/go/os/stat_aix.go
+++ b/libgo/go/os/stat_aix.go
@@ -1,4 +1,4 @@
-// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2018 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.
 
diff --git a/libgo/go/os/stat_test.go b/libgo/go/os/stat_test.go
new file mode 100644
index 0000000..60f3b4c
--- /dev/null
+++ b/libgo/go/os/stat_test.go
@@ -0,0 +1,292 @@
+// Copyright 2018 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 os_test
+
+import (
+	"internal/testenv"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+// testStatAndLstat verifies that all os.Stat, os.Lstat os.File.Stat and os.Readdir work.
+func testStatAndLstat(t *testing.T, path string, isLink bool, statCheck, lstatCheck func(*testing.T, string, os.FileInfo)) {
+	// test os.Stat
+	sfi, err := os.Stat(path)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	statCheck(t, path, sfi)
+
+	// test os.Lstat
+	lsfi, err := os.Lstat(path)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	lstatCheck(t, path, lsfi)
+
+	if isLink {
+		if os.SameFile(sfi, lsfi) {
+			t.Errorf("stat and lstat of %q should not be the same", path)
+		}
+	} else {
+		if !os.SameFile(sfi, lsfi) {
+			t.Errorf("stat and lstat of %q should be the same", path)
+		}
+	}
+
+	// test os.File.Stat
+	f, err := os.Open(path)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer f.Close()
+
+	sfi2, err := f.Stat()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	statCheck(t, path, sfi2)
+
+	if !os.SameFile(sfi, sfi2) {
+		t.Errorf("stat of open %q file and stat of %q should be the same", path, path)
+	}
+
+	if isLink {
+		if os.SameFile(sfi2, lsfi) {
+			t.Errorf("stat of opened %q file and lstat of %q should not be the same", path, path)
+		}
+	} else {
+		if !os.SameFile(sfi2, lsfi) {
+			t.Errorf("stat of opened %q file and lstat of %q should be the same", path, path)
+		}
+	}
+
+	// test os.FileInfo returned by os.Readdir
+	if len(path) > 0 && os.IsPathSeparator(path[len(path)-1]) {
+		// skip os.Readdir test of directories with slash at the end
+		return
+	}
+	parentdir := filepath.Dir(path)
+	parent, err := os.Open(parentdir)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer parent.Close()
+
+	fis, err := parent.Readdir(-1)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	var lsfi2 os.FileInfo
+	base := filepath.Base(path)
+	for _, fi2 := range fis {
+		if fi2.Name() == base {
+			lsfi2 = fi2
+			break
+		}
+	}
+	if lsfi2 == nil {
+		t.Errorf("failed to find %q in its parent", path)
+		return
+	}
+	lstatCheck(t, path, lsfi2)
+
+	if !os.SameFile(lsfi, lsfi2) {
+		t.Errorf("lstat of %q file in %q directory and %q should be the same", lsfi2.Name(), parentdir, path)
+	}
+}
+
+// testIsDir verifies that fi refers to directory.
+func testIsDir(t *testing.T, path string, fi os.FileInfo) {
+	t.Helper()
+	if !fi.IsDir() {
+		t.Errorf("%q should be a directory", path)
+	}
+	if fi.Mode()&os.ModeSymlink != 0 {
+		t.Errorf("%q should not be a symlink", path)
+	}
+}
+
+// testIsSymlink verifies that fi refers to symlink.
+func testIsSymlink(t *testing.T, path string, fi os.FileInfo) {
+	t.Helper()
+	if fi.IsDir() {
+		t.Errorf("%q should not be a directory", path)
+	}
+	if fi.Mode()&os.ModeSymlink == 0 {
+		t.Errorf("%q should be a symlink", path)
+	}
+}
+
+// testIsFile verifies that fi refers to file.
+func testIsFile(t *testing.T, path string, fi os.FileInfo) {
+	t.Helper()
+	if fi.IsDir() {
+		t.Errorf("%q should not be a directory", path)
+	}
+	if fi.Mode()&os.ModeSymlink != 0 {
+		t.Errorf("%q should not be a symlink", path)
+	}
+}
+
+func testDirStats(t *testing.T, path string) {
+	testStatAndLstat(t, path, false, testIsDir, testIsDir)
+}
+
+func testFileStats(t *testing.T, path string) {
+	testStatAndLstat(t, path, false, testIsFile, testIsFile)
+}
+
+func testSymlinkStats(t *testing.T, path string, isdir bool) {
+	if isdir {
+		testStatAndLstat(t, path, true, testIsDir, testIsSymlink)
+	} else {
+		testStatAndLstat(t, path, true, testIsFile, testIsSymlink)
+	}
+}
+
+func testSymlinkSameFile(t *testing.T, path, link string) {
+	pathfi, err := os.Stat(path)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	linkfi, err := os.Stat(link)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if !os.SameFile(pathfi, linkfi) {
+		t.Errorf("os.Stat(%q) and os.Stat(%q) are not the same file", path, link)
+	}
+
+	linkfi, err = os.Lstat(link)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if os.SameFile(pathfi, linkfi) {
+		t.Errorf("os.Stat(%q) and os.Lstat(%q) are the same file", path, link)
+	}
+}
+
+func TestDirAndSymlinkStats(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+
+	tmpdir, err := ioutil.TempDir("", "TestDirAndSymlinkStats")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	dir := filepath.Join(tmpdir, "dir")
+	err = os.Mkdir(dir, 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testDirStats(t, dir)
+
+	dirlink := filepath.Join(tmpdir, "link")
+	err = os.Symlink(dir, dirlink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testSymlinkStats(t, dirlink, true)
+	testSymlinkSameFile(t, dir, dirlink)
+
+	linklink := filepath.Join(tmpdir, "linklink")
+	err = os.Symlink(dirlink, linklink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testSymlinkStats(t, linklink, true)
+	testSymlinkSameFile(t, dir, linklink)
+}
+
+func TestFileAndSymlinkStats(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+
+	tmpdir, err := ioutil.TempDir("", "TestFileAndSymlinkStats")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	file := filepath.Join(tmpdir, "file")
+	err = ioutil.WriteFile(file, []byte(""), 0644)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testFileStats(t, file)
+
+	filelink := filepath.Join(tmpdir, "link")
+	err = os.Symlink(file, filelink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testSymlinkStats(t, filelink, false)
+	testSymlinkSameFile(t, file, filelink)
+
+	linklink := filepath.Join(tmpdir, "linklink")
+	err = os.Symlink(filelink, linklink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	testSymlinkStats(t, linklink, false)
+	testSymlinkSameFile(t, file, linklink)
+}
+
+// see issue 27225 for details
+func TestSymlinkWithTrailingSlash(t *testing.T) {
+	testenv.MustHaveSymlink(t)
+
+	tmpdir, err := ioutil.TempDir("", "TestSymlinkWithTrailingSlash")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	dir := filepath.Join(tmpdir, "dir")
+	err = os.Mkdir(dir, 0777)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dirlink := filepath.Join(tmpdir, "link")
+	err = os.Symlink(dir, dirlink)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dirlinkWithSlash := dirlink + string(os.PathSeparator)
+
+	if runtime.GOOS == "windows" {
+		testSymlinkStats(t, dirlinkWithSlash, true)
+	} else {
+		testDirStats(t, dirlinkWithSlash)
+	}
+
+	fi1, err := os.Stat(dir)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	fi2, err := os.Stat(dirlinkWithSlash)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if !os.SameFile(fi1, fi2) {
+		t.Errorf("os.Stat(%q) and os.Stat(%q) are not the same file", dir, dirlinkWithSlash)
+	}
+}
diff --git a/libgo/go/os/sticky_bsd.go b/libgo/go/os/sticky_bsd.go
index 6b54c75..ae2744f 100644
--- a/libgo/go/os/sticky_bsd.go
+++ b/libgo/go/os/sticky_bsd.go
@@ -2,7 +2,7 @@
 // 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
+// +build aix darwin dragonfly freebsd netbsd openbsd solaris
 
 package os
 
diff --git a/libgo/go/os/sticky_notbsd.go b/libgo/go/os/sticky_notbsd.go
index 834e79b..edb5f69 100644
--- a/libgo/go/os/sticky_notbsd.go
+++ b/libgo/go/os/sticky_notbsd.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !aix
 // +build !darwin
 // +build !dragonfly
 // +build !freebsd
diff --git a/libgo/go/os/sys_aix.go b/libgo/go/os/sys_aix.go
new file mode 100644
index 0000000..53a40f2
--- /dev/null
+++ b/libgo/go/os/sys_aix.go
@@ -0,0 +1,26 @@
+// Copyright 2018 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 os
+
+import "syscall"
+
+// gethostname syscall cannot be used because it also returns the domain.
+// Therefore, hostname is retrieve with uname syscall and the Nodename field.
+
+func hostname() (name string, err error) {
+	var u syscall.Utsname
+	if errno := syscall.Uname(&u); errno != nil {
+		return "", NewSyscallError("uname", errno)
+	}
+	b := make([]byte, len(u.Nodename))
+	i := 0
+	for ; i < len(u.Nodename); i++ {
+		if u.Nodename[i] == 0 {
+			break
+		}
+		b[i] = byte(u.Nodename[i])
+	}
+	return string(b[:i]), nil
+}
diff --git a/libgo/go/os/types.go b/libgo/go/os/types.go
index b0b7d8d..4b6c084 100644
--- a/libgo/go/os/types.go
+++ b/libgo/go/os/types.go
@@ -57,7 +57,7 @@ const (
 	ModeIrregular                                  // ?: non-regular file; nothing else is known about this file
 
 	// Mask for the type bits. For regular files, none will be set.
-	ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice | ModeIrregular
+	ModeType = ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice | ModeCharDevice | ModeIrregular
 
 	ModePerm FileMode = 0777 // Unix permission bits
 )
diff --git a/libgo/go/os/types_windows.go b/libgo/go/os/types_windows.go
index f3297c0..5e33292 100644
--- a/libgo/go/os/types_windows.go
+++ b/libgo/go/os/types_windows.go
@@ -47,6 +47,21 @@ func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (f
 	if err != nil {
 		return nil, &PathError{"GetFileInformationByHandle", path, err}
 	}
+
+	var ti windows.FILE_ATTRIBUTE_TAG_INFO
+	err = windows.GetFileInformationByHandleEx(h, windows.FileAttributeTagInfo, (*byte)(unsafe.Pointer(&ti)), uint32(unsafe.Sizeof(ti)))
+	if err != nil {
+		if errno, ok := err.(syscall.Errno); ok && errno == windows.ERROR_INVALID_PARAMETER {
+			// It appears calling GetFileInformationByHandleEx with
+			// FILE_ATTRIBUTE_TAG_INFO fails on FAT file system with
+			// ERROR_INVALID_PARAMETER. Clear ti.ReparseTag in that
+			// instance to indicate no symlinks are possible.
+			ti.ReparseTag = 0
+		} else {
+			return nil, &PathError{"GetFileInformationByHandleEx", path, err}
+		}
+	}
+
 	return &fileStat{
 		name:           basename(path),
 		FileAttributes: d.FileAttributes,
@@ -58,6 +73,7 @@ func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (f
 		vol:            d.VolumeSerialNumber,
 		idxhi:          d.FileIndexHigh,
 		idxlo:          d.FileIndexLow,
+		Reserved0:      ti.ReparseTag,
 		// fileStat.path is used by os.SameFile to decide if it needs
 		// to fetch vol, idxhi and idxlo. But these are already set,
 		// so set fileStat.path to "" to prevent os.SameFile doing it again.
@@ -78,67 +94,6 @@ func newFileStatFromWin32finddata(d *syscall.Win32finddata) *fileStat {
 	}
 }
 
-// newFileStatFromGetFileAttributesExOrFindFirstFile calls GetFileAttributesEx
-// and FindFirstFile to gather all required information about the provided file path pathp.
-func newFileStatFromGetFileAttributesExOrFindFirstFile(path string, pathp *uint16) (*fileStat, error) {
-	// As suggested by Microsoft, use GetFileAttributes() to acquire the file information,
-	// and if it's a reparse point use FindFirstFile() to get the tag:
-	// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363940(v=vs.85).aspx
-	// Notice that always calling FindFirstFile can create performance problems
-	// (https://golang.org/issues/19922#issuecomment-300031421)
-	var fa syscall.Win32FileAttributeData
-	err := syscall.GetFileAttributesEx(pathp, syscall.GetFileExInfoStandard, (*byte)(unsafe.Pointer(&fa)))
-	if err == nil && fa.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 {
-		// Not a symlink.
-		return &fileStat{
-			FileAttributes: fa.FileAttributes,
-			CreationTime:   fa.CreationTime,
-			LastAccessTime: fa.LastAccessTime,
-			LastWriteTime:  fa.LastWriteTime,
-			FileSizeHigh:   fa.FileSizeHigh,
-			FileSizeLow:    fa.FileSizeLow,
-		}, nil
-	}
-	// GetFileAttributesEx returns ERROR_INVALID_NAME if called
-	// for invalid file name like "*.txt". Do not attempt to call
-	// FindFirstFile with "*.txt", because FindFirstFile will
-	// succeed. So just return ERROR_INVALID_NAME instead.
-	// see https://golang.org/issue/24999 for details.
-	if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_NAME {
-		return nil, &PathError{"GetFileAttributesEx", path, err}
-	}
-	// We might have symlink here. But some directories also have
-	// FileAttributes FILE_ATTRIBUTE_REPARSE_POINT bit set.
-	// For example, OneDrive directory is like that
-	// (see golang.org/issue/22579 for details).
-	// So use FindFirstFile instead to distinguish directories like
-	// OneDrive from real symlinks (see instructions described at
-	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
-	// and in particular bits about using both FileAttributes and
-	// Reserved0 fields).
-	var fd syscall.Win32finddata
-	sh, err := syscall.FindFirstFile(pathp, &fd)
-	if err != nil {
-		return nil, &PathError{"FindFirstFile", path, err}
-	}
-	syscall.FindClose(sh)
-
-	return newFileStatFromWin32finddata(&fd), nil
-}
-
-func (fs *fileStat) updatePathAndName(name string) error {
-	fs.path = name
-	if !isAbs(fs.path) {
-		var err error
-		fs.path, err = syscall.FullPath(fs.path)
-		if err != nil {
-			return &PathError{"FullPath", name, err}
-		}
-	}
-	fs.name = basename(name)
-	return nil
-}
-
 func (fs *fileStat) isSymlink() bool {
 	// Use instructions described at
 	// https://blogs.msdn.microsoft.com/oldnewthing/20100212-00/?p=14963/
@@ -211,7 +166,13 @@ func (fs *fileStat) loadFileId() error {
 	if err != nil {
 		return err
 	}
-	h, err := syscall.CreateFile(pathp, 0, 0, nil, syscall.OPEN_EXISTING, syscall.FILE_FLAG_BACKUP_SEMANTICS, 0)
+	attrs := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
+	if fs.isSymlink() {
+		// Use FILE_FLAG_OPEN_REPARSE_POINT, otherwise CreateFile will follow symlink.
+		// See https://docs.microsoft.com/en-us/windows/desktop/FileIO/symbolic-link-effects-on-file-systems-functions#createfile-and-createfiletransacted
+		attrs |= syscall.FILE_FLAG_OPEN_REPARSE_POINT
+	}
+	h, err := syscall.CreateFile(pathp, 0, 0, nil, syscall.OPEN_EXISTING, attrs, 0)
 	if err != nil {
 		return err
 	}
diff --git a/libgo/go/os/user/lookup.go b/libgo/go/os/user/lookup.go
index 2243a25..b36b7c0 100644
--- a/libgo/go/os/user/lookup.go
+++ b/libgo/go/os/user/lookup.go
@@ -7,6 +7,10 @@ package user
 import "sync"
 
 // Current returns the current user.
+//
+// The first call will cache the current user information.
+// Subsequent calls will return the cached value and will not reflect
+// changes to the current user.
 func Current() (*User, error) {
 	cache.Do(func() { cache.u, cache.err = current() })
 	if cache.err != nil {
diff --git a/libgo/go/os/user/lookup_stubs.go b/libgo/go/os/user/lookup_stubs.go
index f7d138f..61bf1dc 100644
--- a/libgo/go/os/user/lookup_stubs.go
+++ b/libgo/go/os/user/lookup_stubs.go
@@ -19,8 +19,15 @@ func init() {
 }
 
 func current() (*User, error) {
-	u := &User{
-		Uid:      currentUID(),
+	uid := currentUID()
+	// $USER and /etc/passwd may disagree; prefer the latter if we can get it.
+	// See issue 27524 for more information.
+	u, err := lookupUserId(uid)
+	if err == nil {
+		return u, nil
+	}
+	u = &User{
+		Uid:      uid,
 		Gid:      currentGID(),
 		Username: os.Getenv("USER"),
 		Name:     "", // ignored
@@ -58,8 +65,8 @@ func current() (*User, error) {
 }
 
 func listGroups(*User) ([]string, error) {
-	if runtime.GOOS == "android" {
-		return nil, errors.New("user: GroupIds not implemented on Android")
+	if runtime.GOOS == "android" || runtime.GOOS == "aix" {
+		return nil, errors.New(fmt.Sprintf("user: GroupIds not implemented on %s", runtime.GOOS))
 	}
 	return nil, errors.New("user: GroupIds requires cgo")
 }
diff --git a/libgo/go/os/user/lookup_unix.go b/libgo/go/os/user/lookup_unix.go
index c4e9ba1..be62f4d 100644
--- a/libgo/go/os/user/lookup_unix.go
+++ b/libgo/go/os/user/lookup_unix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd js,wasm !android,linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd js,wasm !android,linux nacl netbsd openbsd solaris
 // +build !cgo osusergo
 
 package user
diff --git a/libgo/go/os/user/lookup_unix_test.go b/libgo/go/os/user/lookup_unix_test.go
index 02c88ab..65fe065 100644
--- a/libgo/go/os/user/lookup_unix_test.go
+++ b/libgo/go/os/user/lookup_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd !android,linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd !android,linux nacl netbsd openbsd solaris
 // +build !cgo
 
 package user
diff --git a/libgo/go/os/user/user.go b/libgo/go/os/user/user.go
index 1f733b8..c1b8101 100644
--- a/libgo/go/os/user/user.go
+++ b/libgo/go/os/user/user.go
@@ -11,7 +11,7 @@ parses /etc/passwd and /etc/group. The other is cgo-based and relies on
 the standard C library (libc) routines such as getpwuid_r and getgrnam_r.
 
 When cgo is available, cgo-based (libc-backed) code is used by default.
-This can be overriden by using osusergo build tag, which enforces
+This can be overridden by using osusergo build tag, which enforces
 the pure Go implementation.
 */
 package user
diff --git a/libgo/go/os/user/user_test.go b/libgo/go/os/user/user_test.go
index 8fd760e..2563077 100644
--- a/libgo/go/os/user/user_test.go
+++ b/libgo/go/os/user/user_test.go
@@ -5,33 +5,18 @@
 package user
 
 import (
-	"internal/testenv"
-	"os"
 	"runtime"
 	"testing"
 )
 
 func checkUser(t *testing.T) {
+	t.Helper()
 	if !userImplemented {
 		t.Skip("user: not implemented; skipping tests")
 	}
 }
 
 func TestCurrent(t *testing.T) {
-	// The Go builders (in particular the ones using containers)
-	// often have minimal environments without $HOME or $USER set,
-	// which breaks Current which relies on those working as a
-	// fallback.
-	// TODO: we should fix that (Issue 24884) and remove these
-	// workarounds.
-	if testenv.Builder() != "" && runtime.GOOS != "windows" && runtime.GOOS != "plan9" {
-		if os.Getenv("HOME") == "" {
-			os.Setenv("HOME", "/tmp")
-		}
-		if os.Getenv("USER") == "" {
-			os.Setenv("USER", "gobuilder")
-		}
-	}
 	u, err := Current()
 	if err != nil {
 		t.Fatalf("Current: %v (got %#v)", err, u)
@@ -108,6 +93,7 @@ func TestLookupId(t *testing.T) {
 }
 
 func checkGroup(t *testing.T) {
+	t.Helper()
 	if !groupImplemented {
 		t.Skip("user: group not implemented; skipping test")
 	}
diff --git a/libgo/go/os/wait_unimp.go b/libgo/go/os/wait_unimp.go
index d070604..469abf7 100644
--- a/libgo/go/os/wait_unimp.go
+++ b/libgo/go/os/wait_unimp.go
@@ -7,7 +7,7 @@
 package os
 
 // blockUntilWaitable attempts to block until a call to p.Wait will
-// succeed immediately, and returns whether it has done so.
+// succeed immediately, and reports whether it has done so.
 // It does not actually call p.Wait.
 // This version is used on systems that do not implement waitid,
 // or where we have not implemented it yet.
diff --git a/libgo/go/os/wait_wait6.go b/libgo/go/os/wait_wait6.go
index 891f242..45bf649 100644
--- a/libgo/go/os/wait_wait6.go
+++ b/libgo/go/os/wait_wait6.go
@@ -14,7 +14,7 @@ import (
 const _P_PID = 0
 
 // blockUntilWaitable attempts to block until a call to p.Wait will
-// succeed immediately, and returns whether it has done so.
+// succeed immediately, and reports whether it has done so.
 // It does not actually call p.Wait.
 func (p *Process) blockUntilWaitable() (bool, error) {
 	var errno syscall.Errno
diff --git a/libgo/go/os/wait_waitid.go b/libgo/go/os/wait_waitid.go
index a6284aa..4bb77f9 100644
--- a/libgo/go/os/wait_waitid.go
+++ b/libgo/go/os/wait_waitid.go
@@ -18,7 +18,7 @@ import (
 const _P_PID = 1
 
 // blockUntilWaitable attempts to block until a call to p.Wait will
-// succeed immediately, and returns whether it has done so.
+// succeed immediately, and reports whether it has done so.
 // It does not actually call p.Wait.
 func (p *Process) blockUntilWaitable() (bool, error) {
 	// The waitid system call expects a pointer to a siginfo_t,