libgo: update to Go1.16beta1 release

This does not yet include support for the //go:embed directive added
in this release.

	* Makefile.am (check-runtime): Don't create check-runtime-dir.
	(mostlyclean-local): Don't remove check-runtime-dir.
	(check-go-tool, check-vet): Copy in go.mod and modules.txt.
	(check-cgo-test, check-carchive-test): Add go.mod file.
	* Makefile.in: Regenerate.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/280172

67 files changed, 1896 insertions, 561 deletions

diff --git a/libgo/go/os/dir.go b/libgo/go/os/dir.go
index 1d7ced8..5306bcb 100644
--- a/libgo/go/os/dir.go
+++ b/libgo/go/os/dir.go
@@ -4,6 +4,19 @@
 
 package os
 
+import (
+	"io/fs"
+	"sort"
+)
+
+type readdirMode int
+
+const (
+	readdirName readdirMode = iota
+	readdirDirEntry
+	readdirFileInfo
+)
+
 // Readdir reads the contents of the directory associated with file and
 // returns a slice of up to n FileInfo values, as would be returned
 // by Lstat, in directory order. Subsequent calls on the same file will yield
@@ -19,11 +32,20 @@ package os
 // nil error. If it encounters an error before the end of the
 // directory, Readdir returns the FileInfo read until that point
 // and a non-nil error.
+//
+// Most clients are better served by the more efficient ReadDir method.
 func (f *File) Readdir(n int) ([]FileInfo, error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
-	return f.readdir(n)
+	_, _, infos, err := f.readdir(n, readdirFileInfo)
+	if infos == nil {
+		// Readdir has historically always returned a non-nil empty slice, never nil,
+		// even on error (except misuse with nil receiver above).
+		// Keep it that way to avoid breaking overly sensitive callers.
+		infos = []FileInfo{}
+	}
+	return infos, err
 }
 
 // Readdirnames reads the contents of the directory associated with file
@@ -45,5 +67,59 @@ func (f *File) Readdirnames(n int) (names []string, err error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
-	return f.readdirnames(n)
+	names, _, _, err = f.readdir(n, readdirName)
+	if names == nil {
+		// Readdirnames has historically always returned a non-nil empty slice, never nil,
+		// even on error (except misuse with nil receiver above).
+		// Keep it that way to avoid breaking overly sensitive callers.
+		names = []string{}
+	}
+	return names, err
+}
+
+// A DirEntry is an entry read from a directory
+// (using the ReadDir function or a File's ReadDir method).
+type DirEntry = fs.DirEntry
+
+// ReadDir reads the contents of the directory associated with the file f
+// and returns a slice of DirEntry values in directory order.
+// Subsequent calls on the same file will yield later DirEntry records in the directory.
+//
+// If n > 0, ReadDir returns at most n DirEntry records.
+// In this case, if ReadDir returns an empty slice, it will return an error explaining why.
+// At the end of a directory, the error is io.EOF.
+//
+// If n <= 0, ReadDir returns all the DirEntry records remaining in the directory.
+// When it succeeds, it returns a nil error (not io.EOF).
+func (f *File) ReadDir(n int) ([]DirEntry, error) {
+	if f == nil {
+		return nil, ErrInvalid
+	}
+	_, dirents, _, err := f.readdir(n, readdirDirEntry)
+	if dirents == nil {
+		// Match Readdir and Readdirnames: don't return nil slices.
+		dirents = []DirEntry{}
+	}
+	return dirents, err
+}
+
+// testingForceReadDirLstat forces ReadDir to call Lstat, for testing that code path.
+// This can be difficult to provoke on some Unix systems otherwise.
+var testingForceReadDirLstat bool
+
+// ReadDir reads the named directory,
+// returning all its directory entries sorted by filename.
+// If an error occurs reading the directory,
+// ReadDir returns the entries it was able to read before the error,
+// along with the error.
+func ReadDir(name string) ([]DirEntry, error) {
+	f, err := Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	dirs, err := f.ReadDir(-1)
+	sort.Slice(dirs, func(i, j int) bool { return dirs[i].Name() < dirs[j].Name() })
+	return dirs, err
 }
diff --git a/libgo/go/os/dir_gccgo.go b/libgo/go/os/dir_gccgo.go
index 171dde5..31ee262 100644
--- a/libgo/go/os/dir_gccgo.go
+++ b/libgo/go/os/dir_gccgo.go
@@ -5,9 +5,8 @@
 package os
 
 import (
+	"internal/poll"
 	"io"
-	"runtime"
-	"sync/atomic"
 	"syscall"
 	"unsafe"
 )
@@ -16,8 +15,7 @@ import (
 //extern pathconf
 func libc_pathconf(*byte, int32) int
 
-//extern dup
-func libc_dup(int32) int32
+func direntType(*syscall.Dirent) byte
 
 func clen(n []byte) int {
 	for i := 0; i < len(n); i++ {
@@ -28,95 +26,118 @@ func clen(n []byte) int {
 	return len(n)
 }
 
-var nameMax int32
-
-func (file *File) readdirnames(n int) (names []string, err error) {
-	if file.dirinfo == nil {
-		p, err := syscall.BytePtrFromString(file.name)
+func (f *File) readdir(n int, mode readdirMode) (names []string, dirents []DirEntry, infos []FileInfo, err error) {
+	// If this file has no dirinfo, create one.
+	if f.dirinfo == nil {
+		fd, call, err := poll.DupCloseOnExec(int(f.pfd.Sysfd))
 		if err != nil {
-			return nil, err
-		}
-
-		elen := int(atomic.LoadInt32(&nameMax))
-		if elen == 0 {
-			syscall.Entersyscall()
-			plen := libc_pathconf(p, syscall.PC_NAME_MAX)
-			syscall.Exitsyscall()
-			if plen < 1024 {
-				plen = 1024
-			}
-			var dummy syscall.Dirent
-			elen = int(unsafe.Offsetof(dummy.Name)) + plen + 1
-			atomic.StoreInt32(&nameMax, int32(elen))
+			return nil, nil, nil, NewSyscallError(call, err)
 		}
 
 		syscall.Entersyscall()
-		fd := libc_dup(int32(file.pfd.Sysfd))
+		r := libc_fdopendir(int32(fd))
 		errno := syscall.GetErrno()
 		syscall.Exitsyscall()
-		if fd < 0 {
-			return nil, &PathError{"dup", file.name, errno}
-		}
-
-		syscall.Entersyscall()
-		r := libc_fdopendir(fd)
-		errno = syscall.GetErrno()
-		syscall.Exitsyscall()
 		if r == nil {
-			return nil, &PathError{"fdopendir", file.name, errno}
+			return nil, nil, nil, &PathError{"fdopendir", f.name, errno}
 		}
 
-		file.dirinfo = new(dirInfo)
-		file.dirinfo.buf = make([]byte, elen)
-		file.dirinfo.dir = r
+		f.dirinfo = &dirInfo{r}
 	}
-
-	entryDirent := (*syscall.Dirent)(unsafe.Pointer(&file.dirinfo.buf[0]))
-
-	size := n
-	if size <= 0 {
-		size = 100
+	dir := f.dirinfo.dir
+
+	// Change the meaning of n for the implementation below.
+	//
+	// The n above was for the public interface of "if n <= 0,
+	// Readdir returns all the FileInfo from the directory in a
+	// single slice".
+	//
+	// But below, we use only negative to mean looping until the
+	// end and positive to mean bounded, with positive
+	// terminating at 0.
+	if n == 0 {
 		n = -1
 	}
 
-	names = make([]string, 0, size) // Empty with room to grow.
-
 	for n != 0 {
-		var dirent *syscall.Dirent
-		pr := &dirent
 		syscall.Entersyscall()
-		i := libc_readdir_r(file.dirinfo.dir, entryDirent, pr)
+		syscall.SetErrno(0)
+		dirent := libc_readdir(dir)
+		errno := syscall.GetErrno()
 		syscall.Exitsyscall()
-		// On AIX when readdir_r hits EOF it sets dirent to nil and returns 9.
-		//  https://www.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.basetrf2/readdir_r.htm
-		if runtime.GOOS == "aix" && i == 9 && dirent == nil {
-			break
-		}
-		if i != 0 {
-			return names, NewSyscallError("readdir_r", i)
-		}
+
 		if dirent == nil {
+			if errno != 0 {
+				return names, dirents, infos, &PathError{Op: "readdir", Path: f.name, Err: errno}
+			}
 			break // EOF
 		}
-		bytes := (*[10000]byte)(unsafe.Pointer(&dirent.Name[0]))
-		var name = string(bytes[0:clen(bytes[:])])
-		if name == "." || name == ".." { // Useless names
+
+		// In some cases the actual name can be longer than
+		// the Name field.
+		name := (*[1 << 16]byte)(unsafe.Pointer(&dirent.Name[0]))[:]
+		for i, c := range name {
+			if c == 0 {
+				name = name[:i]
+				break
+			}
+		}
+		// Check for useless names before allocating a string.
+		if (len(name) == 1 && name[0] == '.') || (len(name) == 2 && name[0] == '.' && name[1] == '.') {
 			continue
 		}
-		names = append(names, name)
-		n--
-	}
-	if n >= 0 && len(names) == 0 {
-		return names, io.EOF
+		if n > 0 { // see 'n == 0' comment above
+			n--
+		}
+		if mode == readdirName {
+			names = append(names, string(name))
+		} else if mode == readdirDirEntry {
+			var typ FileMode
+			switch direntType(dirent) {
+			case 'B':
+				typ = ModeDevice
+			case 'C':
+				typ = ModeDevice | ModeCharDevice
+			case 'D':
+				typ = ModeDir
+			case 'F':
+				typ = ModeNamedPipe
+			case 'L':
+				typ = ModeSymlink
+			case 'R':
+				typ = 0
+			case 'S':
+				typ = ModeSocket
+			case 'U':
+				typ = ^FileMode(0)
+			}
+
+			de, err := newUnixDirent(f.name, string(name), typ)
+			if IsNotExist(err) {
+				// File disappeared between readdir and stat.
+				// Treat as if it didn't exist.
+				continue
+			}
+			if err != nil {
+				return nil, dirents, nil, err
+			}
+			dirents = append(dirents, de)
+		} else {
+			info, err := lstat(f.name + "/" + string(name))
+			if IsNotExist(err) {
+				// File disappeared between readdir + stat.
+				// Treat as if it didn't exist.
+				continue
+			}
+			if err != nil {
+				return nil, nil, infos, err
+			}
+			infos = append(infos, info)
+		}
 	}
-	return names, nil
-}
 
-func (f *File) seekInvalidate() {
-	if f.file.dirinfo != nil {
-		syscall.Entersyscall()
-		libc_closedir(f.file.dirinfo.dir)
-		syscall.Exitsyscall()
-		f.file.dirinfo = nil
+	if n > 0 && len(names)+len(dirents)+len(infos) == 0 {
+		return nil, nil, nil, io.EOF
 	}
+	return names, dirents, infos, nil
 }
diff --git a/libgo/go/os/dir_gccgo_c.c b/libgo/go/os/dir_gccgo_c.c
new file mode 100644
index 0000000..66b9be1
--- /dev/null
+++ b/libgo/go/os/dir_gccgo_c.c
@@ -0,0 +1,58 @@
+/* Copyright 2020 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.  */
+
+#include <dirent.h>
+
+#include "runtime.h"
+
+unsigned char direntType (struct dirent *)
+  __asm__ (GOSYM_PREFIX "os.direntType");
+
+unsigned char
+direntType (struct dirent *p __attribute__((unused)))
+{
+#ifndef HAVE_STRUCT_DIRENT_D_TYPE
+  return 'U';
+#else
+  switch (p->d_type)
+    {
+#ifdef DT_BLK
+    case DT_BLK:
+      return 'B';
+#endif
+#ifdef DT_CHR
+    case DT_CHR:
+      return 'C';
+#endif
+#ifdef DT_DBF
+    case DT_DBF:
+      // Database record file.
+      // Treat as regular file.
+      return 'R';
+#endif
+#ifdef DT_DIR
+    case DT_DIR:
+      return 'D';
+#endif
+#ifdef DT_FIFO
+    case DT_FIFO:
+      return 'F';
+#endif
+#ifdef DT_LNK
+    case DT_LNK:
+      return 'L';
+#endif
+#ifdef DT_REG
+    case DT_REG:
+      return 'R';
+#endif
+#ifdef DT_SOCK
+    case DT_SOCK:
+      return 'S';
+#endif
+    default:
+      return 'U';
+    }
+#endif /* HAVE_DIRENT_D_TYPE */
+}
diff --git a/libgo/go/os/dir_largefile.go b/libgo/go/os/dir_largefile.go
index e7d30f8..1fc5ee0 100644
--- a/libgo/go/os/dir_largefile.go
+++ b/libgo/go/os/dir_largefile.go
@@ -11,5 +11,5 @@ package os
 
 import "syscall"
 
-//extern readdir64_r
-func libc_readdir_r(*syscall.DIR, *syscall.Dirent, **syscall.Dirent) syscall.Errno
+//extern readdir64
+func libc_readdir(*syscall.DIR) *syscall.Dirent
diff --git a/libgo/go/os/dir_plan9.go b/libgo/go/os/dir_plan9.go
index 8195c02..8f6b0d6 100644
--- a/libgo/go/os/dir_plan9.go
+++ b/libgo/go/os/dir_plan9.go
@@ -9,7 +9,7 @@ import (
 	"syscall"
 )
 
-func (file *File) readdir(n int) ([]FileInfo, error) {
+func (file *File) readdir(n int, mode readdirMode) (names []string, dirents []DirEntry, infos []FileInfo, err error) {
 	// If this file has no dirinfo, create one.
 	if file.dirinfo == nil {
 		file.dirinfo = new(dirInfo)
@@ -20,7 +20,6 @@ func (file *File) readdir(n int) ([]FileInfo, error) {
 		size = 100
 		n = -1
 	}
-	fi := make([]FileInfo, 0, size) // Empty with room to grow.
 	for n != 0 {
 		// Refill the buffer if necessary.
 		if d.bufp >= d.nbuf {
@@ -33,10 +32,10 @@ func (file *File) readdir(n int) ([]FileInfo, error) {
 				if err == io.EOF {
 					break
 				}
-				return fi, &PathError{"readdir", file.name, err}
+				return names, dirents, infos, &PathError{Op: "readdir", Path: file.name, Err: err}
 			}
 			if nb < syscall.STATFIXLEN {
-				return fi, &PathError{"readdir", file.name, syscall.ErrShortStat}
+				return names, dirents, infos, &PathError{Op: "readdir", Path: file.name, Err: syscall.ErrShortStat}
 			}
 		}
 
@@ -44,30 +43,39 @@ func (file *File) readdir(n int) ([]FileInfo, error) {
 		b := d.buf[d.bufp:]
 		m := int(uint16(b[0])|uint16(b[1])<<8) + 2
 		if m < syscall.STATFIXLEN {
-			return fi, &PathError{"readdir", file.name, syscall.ErrShortStat}
+			return names, dirents, infos, &PathError{Op: "readdir", Path: file.name, Err: syscall.ErrShortStat}
 		}
 
 		dir, err := syscall.UnmarshalDir(b[:m])
 		if err != nil {
-			return fi, &PathError{"readdir", file.name, err}
+			return names, dirents, infos, &PathError{Op: "readdir", Path: file.name, Err: err}
 		}
-		fi = append(fi, fileInfoFromStat(dir))
 
+		if mode == readdirName {
+			names = append(names, dir.Name)
+		} else {
+			f := fileInfoFromStat(dir)
+			if mode == readdirDirEntry {
+				dirents = append(dirents, dirEntry{f})
+			} else {
+				infos = append(infos, f)
+			}
+		}
 		d.bufp += m
 		n--
 	}
 
-	if n >= 0 && len(fi) == 0 {
-		return fi, io.EOF
+	if n > 0 && len(names)+len(dirents)+len(infos) == 0 {
+		return nil, nil, nil, io.EOF
 	}
-	return fi, nil
+	return names, dirents, infos, nil
 }
 
-func (file *File) readdirnames(n int) (names []string, err error) {
-	fi, err := file.Readdir(n)
-	names = make([]string, len(fi))
-	for i := range fi {
-		names[i] = fi[i].Name()
-	}
-	return
+type dirEntry struct {
+	fs *fileStat
 }
+
+func (de dirEntry) Name() string            { return de.fs.Name() }
+func (de dirEntry) IsDir() bool             { return de.fs.IsDir() }
+func (de dirEntry) Type() FileMode          { return de.fs.Mode().Type() }
+func (de dirEntry) Info() (FileInfo, error) { return de.fs, nil }
diff --git a/libgo/go/os/dir_regfile.go b/libgo/go/os/dir_regfile.go
index b2e6623..3a0cd64 100644
--- a/libgo/go/os/dir_regfile.go
+++ b/libgo/go/os/dir_regfile.go
@@ -15,5 +15,5 @@ package os
 
 import "syscall"
 
-//extern-sysinfo readdir_r
-func libc_readdir_r(*syscall.DIR, *syscall.Dirent, **syscall.Dirent) syscall.Errno
+//extern-sysinfo readdir
+func libc_readdir(*syscall.DIR) *syscall.Dirent
diff --git a/libgo/go/os/error.go b/libgo/go/os/error.go
index 875cc97..704a6fb 100644
--- a/libgo/go/os/error.go
+++ b/libgo/go/os/error.go
@@ -7,6 +7,7 @@ package os
 import (
 	"internal/oserror"
 	"internal/poll"
+	"io/fs"
 )
 
 // Portable analogs of some common system call errors.
@@ -16,20 +17,17 @@ import (
 var (
 	// ErrInvalid indicates an invalid argument.
 	// Methods on File will return this error when the receiver is nil.
-	ErrInvalid = errInvalid() // "invalid argument"
+	ErrInvalid = fs.ErrInvalid // "invalid argument"
+
+	ErrPermission = fs.ErrPermission // "permission denied"
+	ErrExist      = fs.ErrExist      // "file already exists"
+	ErrNotExist   = fs.ErrNotExist   // "file does not exist"
+	ErrClosed     = fs.ErrClosed     // "file already closed"
 
-	ErrPermission       = errPermission()       // "permission denied"
-	ErrExist            = errExist()            // "file already exists"
-	ErrNotExist         = errNotExist()         // "file does not exist"
-	ErrClosed           = errClosed()           // "file already closed"
 	ErrNoDeadline       = errNoDeadline()       // "file type does not support deadline"
 	ErrDeadlineExceeded = errDeadlineExceeded() // "i/o timeout"
 )
 
-func errInvalid() error    { return oserror.ErrInvalid }
-func errPermission() error { return oserror.ErrPermission }
-func errExist() error      { return oserror.ErrExist }
-func errNotExist() error   { return oserror.ErrNotExist }
 func errClosed() error     { return oserror.ErrClosed }
 func errNoDeadline() error { return poll.ErrNoDeadline }
 
@@ -47,21 +45,7 @@ type timeout interface {
 }
 
 // PathError records an error and the operation and file path that caused it.
-type PathError struct {
-	Op   string
-	Path string
-	Err  error
-}
-
-func (e *PathError) Error() string { return e.Op + " " + e.Path + ": " + e.Err.Error() }
-
-func (e *PathError) Unwrap() error { return e.Err }
-
-// Timeout reports whether this error represents a timeout.
-func (e *PathError) Timeout() bool {
-	t, ok := e.Err.(timeout)
-	return ok && t.Timeout()
-}
+type PathError = fs.PathError
 
 // SyscallError records an error from a specific system call.
 type SyscallError struct {
@@ -92,6 +76,9 @@ func NewSyscallError(syscall string, err error) error {
 // IsExist returns a boolean indicating whether the error is known to report
 // that a file or directory already exists. It is satisfied by ErrExist as
 // well as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, os.ErrExist).
 func IsExist(err error) bool {
 	return underlyingErrorIs(err, ErrExist)
 }
@@ -99,6 +86,9 @@ func IsExist(err error) bool {
 // IsNotExist returns a boolean indicating whether the error is known to
 // report that a file or directory does not exist. It is satisfied by
 // ErrNotExist as well as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, os.ErrNotExist).
 func IsNotExist(err error) bool {
 	return underlyingErrorIs(err, ErrNotExist)
 }
@@ -106,12 +96,21 @@ func IsNotExist(err error) bool {
 // IsPermission returns a boolean indicating whether the error is known to
 // report that permission is denied. It is satisfied by ErrPermission as well
 // as some syscall errors.
+//
+// This function predates errors.Is. It only supports errors returned by
+// the os package. New code should use errors.Is(err, os.ErrPermission).
 func IsPermission(err error) bool {
 	return underlyingErrorIs(err, ErrPermission)
 }
 
 // IsTimeout returns a boolean indicating whether the error is known
 // to report that a timeout occurred.
+//
+// This function predates errors.Is, and the notion of whether an
+// error indicates a timeout can be ambiguous. For example, the Unix
+// error EWOULDBLOCK sometimes indicates a timeout and sometimes does not.
+// New code should use errors.Is with a value appropriate to the call
+// returning the error, such as os.ErrDeadlineExceeded.
 func IsTimeout(err error) bool {
 	terr, ok := underlyingError(err).(timeout)
 	return ok && terr.Timeout()
diff --git a/libgo/go/os/error_test.go b/libgo/go/os/error_test.go
index 3d92157..6264ccc 100644
--- a/libgo/go/os/error_test.go
+++ b/libgo/go/os/error_test.go
@@ -7,14 +7,14 @@ package os_test
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
 func TestErrIsExist(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ErrIsExist")
+	f, err := os.CreateTemp("", "_Go_ErrIsExist")
 	if err != nil {
 		t.Fatalf("open ErrIsExist tempfile: %s", err)
 		return
@@ -27,7 +27,7 @@ func TestErrIsExist(t *testing.T) {
 		t.Fatal("Open should have failed")
 		return
 	}
-	if s := checkErrorPredicate("os.IsExist", os.IsExist, err, os.ErrExist); s != "" {
+	if s := checkErrorPredicate("os.IsExist", os.IsExist, err, fs.ErrExist); s != "" {
 		t.Fatal(s)
 		return
 	}
@@ -39,7 +39,7 @@ func testErrNotExist(name string) string {
 		f.Close()
 		return "Open should have failed"
 	}
-	if s := checkErrorPredicate("os.IsNotExist", os.IsNotExist, err, os.ErrNotExist); s != "" {
+	if s := checkErrorPredicate("os.IsNotExist", os.IsNotExist, err, fs.ErrNotExist); s != "" {
 		return s
 	}
 
@@ -47,14 +47,14 @@ func testErrNotExist(name string) string {
 	if err == nil {
 		return "Chdir should have failed"
 	}
-	if s := checkErrorPredicate("os.IsNotExist", os.IsNotExist, err, os.ErrNotExist); s != "" {
+	if s := checkErrorPredicate("os.IsNotExist", os.IsNotExist, err, fs.ErrNotExist); s != "" {
 		return s
 	}
 	return ""
 }
 
 func TestErrIsNotExist(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "_Go_ErrIsNotExist")
+	tmpDir, err := os.MkdirTemp("", "_Go_ErrIsNotExist")
 	if err != nil {
 		t.Fatalf("create ErrIsNotExist tempdir: %s", err)
 		return
@@ -91,18 +91,18 @@ type isExistTest struct {
 }
 
 var isExistTests = []isExistTest{
-	{&os.PathError{Err: os.ErrInvalid}, false, false},
-	{&os.PathError{Err: os.ErrPermission}, false, false},
-	{&os.PathError{Err: os.ErrExist}, true, false},
-	{&os.PathError{Err: os.ErrNotExist}, false, true},
-	{&os.PathError{Err: os.ErrClosed}, false, false},
-	{&os.LinkError{Err: os.ErrInvalid}, false, false},
-	{&os.LinkError{Err: os.ErrPermission}, false, false},
-	{&os.LinkError{Err: os.ErrExist}, true, false},
-	{&os.LinkError{Err: os.ErrNotExist}, false, true},
-	{&os.LinkError{Err: os.ErrClosed}, false, false},
-	{&os.SyscallError{Err: os.ErrNotExist}, false, true},
-	{&os.SyscallError{Err: os.ErrExist}, true, false},
+	{&fs.PathError{Err: fs.ErrInvalid}, false, false},
+	{&fs.PathError{Err: fs.ErrPermission}, false, false},
+	{&fs.PathError{Err: fs.ErrExist}, true, false},
+	{&fs.PathError{Err: fs.ErrNotExist}, false, true},
+	{&fs.PathError{Err: fs.ErrClosed}, false, false},
+	{&os.LinkError{Err: fs.ErrInvalid}, false, false},
+	{&os.LinkError{Err: fs.ErrPermission}, false, false},
+	{&os.LinkError{Err: fs.ErrExist}, true, false},
+	{&os.LinkError{Err: fs.ErrNotExist}, false, true},
+	{&os.LinkError{Err: fs.ErrClosed}, false, false},
+	{&os.SyscallError{Err: fs.ErrNotExist}, false, true},
+	{&os.SyscallError{Err: fs.ErrExist}, true, false},
 	{nil, false, false},
 }
 
@@ -111,14 +111,14 @@ func TestIsExist(t *testing.T) {
 		if is := os.IsExist(tt.err); is != tt.is {
 			t.Errorf("os.IsExist(%T %v) = %v, want %v", tt.err, tt.err, is, tt.is)
 		}
-		if is := errors.Is(tt.err, os.ErrExist); is != tt.is {
-			t.Errorf("errors.Is(%T %v, os.ErrExist) = %v, want %v", tt.err, tt.err, is, tt.is)
+		if is := errors.Is(tt.err, fs.ErrExist); is != tt.is {
+			t.Errorf("errors.Is(%T %v, fs.ErrExist) = %v, want %v", tt.err, tt.err, is, tt.is)
 		}
 		if isnot := os.IsNotExist(tt.err); isnot != tt.isnot {
 			t.Errorf("os.IsNotExist(%T %v) = %v, want %v", tt.err, tt.err, isnot, tt.isnot)
 		}
-		if isnot := errors.Is(tt.err, os.ErrNotExist); isnot != tt.isnot {
-			t.Errorf("errors.Is(%T %v, os.ErrNotExist) = %v, want %v", tt.err, tt.err, isnot, tt.isnot)
+		if isnot := errors.Is(tt.err, fs.ErrNotExist); isnot != tt.isnot {
+			t.Errorf("errors.Is(%T %v, fs.ErrNotExist) = %v, want %v", tt.err, tt.err, isnot, tt.isnot)
 		}
 	}
 }
@@ -130,8 +130,8 @@ type isPermissionTest struct {
 
 var isPermissionTests = []isPermissionTest{
 	{nil, false},
-	{&os.PathError{Err: os.ErrPermission}, true},
-	{&os.SyscallError{Err: os.ErrPermission}, true},
+	{&fs.PathError{Err: fs.ErrPermission}, true},
+	{&os.SyscallError{Err: fs.ErrPermission}, true},
 }
 
 func TestIsPermission(t *testing.T) {
@@ -139,19 +139,19 @@ func TestIsPermission(t *testing.T) {
 		if got := os.IsPermission(tt.err); got != tt.want {
 			t.Errorf("os.IsPermission(%#v) = %v; want %v", tt.err, got, tt.want)
 		}
-		if got := errors.Is(tt.err, os.ErrPermission); got != tt.want {
-			t.Errorf("errors.Is(%#v, os.ErrPermission) = %v; want %v", tt.err, got, tt.want)
+		if got := errors.Is(tt.err, fs.ErrPermission); got != tt.want {
+			t.Errorf("errors.Is(%#v, fs.ErrPermission) = %v; want %v", tt.err, got, tt.want)
 		}
 	}
 }
 
 func TestErrPathNUL(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ErrPathNUL\x00")
+	f, err := os.CreateTemp("", "_Go_ErrPathNUL\x00")
 	if err == nil {
 		f.Close()
 		t.Fatal("TempFile should have failed")
 	}
-	f, err = ioutil.TempFile("", "_Go_ErrPathNUL")
+	f, err = os.CreateTemp("", "_Go_ErrPathNUL")
 	if err != nil {
 		t.Fatalf("open ErrPathNUL tempfile: %s", err)
 	}
@@ -170,8 +170,8 @@ func TestErrPathNUL(t *testing.T) {
 }
 
 func TestPathErrorUnwrap(t *testing.T) {
-	pe := &os.PathError{Err: os.ErrInvalid}
-	if !errors.Is(pe, os.ErrInvalid) {
+	pe := &fs.PathError{Err: fs.ErrInvalid}
+	if !errors.Is(pe, fs.ErrInvalid) {
 		t.Error("errors.Is failed, wanted success")
 	}
 }
@@ -181,7 +181,7 @@ type myErrorIs struct{ error }
 func (e myErrorIs) Is(target error) bool { return target == e.error }
 
 func TestErrorIsMethods(t *testing.T) {
-	if os.IsPermission(myErrorIs{os.ErrPermission}) {
-		t.Error("os.IsPermission(err) = true when err.Is(os.ErrPermission), wanted false")
+	if os.IsPermission(myErrorIs{fs.ErrPermission}) {
+		t.Error("os.IsPermission(err) = true when err.Is(fs.ErrPermission), wanted false")
 	}
 }
diff --git a/libgo/go/os/error_unix_test.go b/libgo/go/os/error_unix_test.go
index a01916e..dd9f317 100644
--- a/libgo/go/os/error_unix_test.go
+++ b/libgo/go/os/error_unix_test.go
@@ -7,14 +7,15 @@
 package os_test
 
 import (
+	"io/fs"
 	"os"
 	"syscall"
 )
 
 func init() {
 	isExistTests = append(isExistTests,
-		isExistTest{err: &os.PathError{Err: syscall.EEXIST}, is: true, isnot: false},
-		isExistTest{err: &os.PathError{Err: syscall.ENOTEMPTY}, is: true, isnot: false},
+		isExistTest{err: &fs.PathError{Err: syscall.EEXIST}, is: true, isnot: false},
+		isExistTest{err: &fs.PathError{Err: syscall.ENOTEMPTY}, is: true, isnot: false},
 
 		isExistTest{err: &os.LinkError{Err: syscall.EEXIST}, is: true, isnot: false},
 		isExistTest{err: &os.LinkError{Err: syscall.ENOTEMPTY}, is: true, isnot: false},
@@ -23,9 +24,9 @@ func init() {
 		isExistTest{err: &os.SyscallError{Err: syscall.ENOTEMPTY}, is: true, isnot: false},
 	)
 	isPermissionTests = append(isPermissionTests,
-		isPermissionTest{err: &os.PathError{Err: syscall.EACCES}, want: true},
-		isPermissionTest{err: &os.PathError{Err: syscall.EPERM}, want: true},
-		isPermissionTest{err: &os.PathError{Err: syscall.EEXIST}, want: false},
+		isPermissionTest{err: &fs.PathError{Err: syscall.EACCES}, want: true},
+		isPermissionTest{err: &fs.PathError{Err: syscall.EPERM}, want: true},
+		isPermissionTest{err: &fs.PathError{Err: syscall.EEXIST}, want: false},
 
 		isPermissionTest{err: &os.LinkError{Err: syscall.EACCES}, want: true},
 		isPermissionTest{err: &os.LinkError{Err: syscall.EPERM}, want: true},
diff --git a/libgo/go/os/error_windows_test.go b/libgo/go/os/error_windows_test.go
index 1635c10..b8191c5 100644
--- a/libgo/go/os/error_windows_test.go
+++ b/libgo/go/os/error_windows_test.go
@@ -7,6 +7,7 @@
 package os_test
 
 import (
+	"io/fs"
 	"os"
 	"syscall"
 )
@@ -15,24 +16,24 @@ func init() {
 	const _ERROR_BAD_NETPATH = syscall.Errno(53)
 
 	isExistTests = append(isExistTests,
-		isExistTest{err: &os.PathError{Err: syscall.ERROR_FILE_NOT_FOUND}, is: false, isnot: true},
+		isExistTest{err: &fs.PathError{Err: syscall.ERROR_FILE_NOT_FOUND}, is: false, isnot: true},
 		isExistTest{err: &os.LinkError{Err: syscall.ERROR_FILE_NOT_FOUND}, is: false, isnot: true},
 		isExistTest{err: &os.SyscallError{Err: syscall.ERROR_FILE_NOT_FOUND}, is: false, isnot: true},
 
-		isExistTest{err: &os.PathError{Err: _ERROR_BAD_NETPATH}, is: false, isnot: true},
+		isExistTest{err: &fs.PathError{Err: _ERROR_BAD_NETPATH}, is: false, isnot: true},
 		isExistTest{err: &os.LinkError{Err: _ERROR_BAD_NETPATH}, is: false, isnot: true},
 		isExistTest{err: &os.SyscallError{Err: _ERROR_BAD_NETPATH}, is: false, isnot: true},
 
-		isExistTest{err: &os.PathError{Err: syscall.ERROR_PATH_NOT_FOUND}, is: false, isnot: true},
+		isExistTest{err: &fs.PathError{Err: syscall.ERROR_PATH_NOT_FOUND}, is: false, isnot: true},
 		isExistTest{err: &os.LinkError{Err: syscall.ERROR_PATH_NOT_FOUND}, is: false, isnot: true},
 		isExistTest{err: &os.SyscallError{Err: syscall.ERROR_PATH_NOT_FOUND}, is: false, isnot: true},
 
-		isExistTest{err: &os.PathError{Err: syscall.ERROR_DIR_NOT_EMPTY}, is: true, isnot: false},
+		isExistTest{err: &fs.PathError{Err: syscall.ERROR_DIR_NOT_EMPTY}, is: true, isnot: false},
 		isExistTest{err: &os.LinkError{Err: syscall.ERROR_DIR_NOT_EMPTY}, is: true, isnot: false},
 		isExistTest{err: &os.SyscallError{Err: syscall.ERROR_DIR_NOT_EMPTY}, is: true, isnot: false},
 	)
 	isPermissionTests = append(isPermissionTests,
-		isPermissionTest{err: &os.PathError{Err: syscall.ERROR_ACCESS_DENIED}, want: true},
+		isPermissionTest{err: &fs.PathError{Err: syscall.ERROR_ACCESS_DENIED}, want: true},
 		isPermissionTest{err: &os.LinkError{Err: syscall.ERROR_ACCESS_DENIED}, want: true},
 		isPermissionTest{err: &os.SyscallError{Err: syscall.ERROR_ACCESS_DENIED}, want: true},
 	)
diff --git a/libgo/go/os/example_test.go b/libgo/go/os/example_test.go
index 822886f..3adce51 100644
--- a/libgo/go/os/example_test.go
+++ b/libgo/go/os/example_test.go
@@ -6,8 +6,10 @@ package os_test
 
 import (
 	"fmt"
+	"io/fs"
 	"log"
 	"os"
+	"path/filepath"
 	"time"
 )
 
@@ -62,9 +64,9 @@ func ExampleFileMode() {
 		fmt.Println("regular file")
 	case mode.IsDir():
 		fmt.Println("directory")
-	case mode&os.ModeSymlink != 0:
+	case mode&fs.ModeSymlink != 0:
 		fmt.Println("symbolic link")
-	case mode&os.ModeNamedPipe != 0:
+	case mode&fs.ModeNamedPipe != 0:
 		fmt.Println("named pipe")
 	}
 }
@@ -143,3 +145,98 @@ func ExampleUnsetenv() {
 	os.Setenv("TMPDIR", "/my/tmp")
 	defer os.Unsetenv("TMPDIR")
 }
+
+func ExampleReadDir() {
+	files, err := os.ReadDir(".")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, file := range files {
+		fmt.Println(file.Name())
+	}
+}
+
+func ExampleMkdirTemp() {
+	dir, err := os.MkdirTemp("", "example")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(dir) // clean up
+
+	file := filepath.Join(dir, "tmpfile")
+	if err := os.WriteFile(file, []byte("content"), 0666); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleMkdirTemp_suffix() {
+	logsDir, err := os.MkdirTemp("", "*-logs")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(logsDir) // clean up
+
+	// Logs can be cleaned out earlier if needed by searching
+	// for all directories whose suffix ends in *-logs.
+	globPattern := filepath.Join(os.TempDir(), "*-logs")
+	matches, err := filepath.Glob(globPattern)
+	if err != nil {
+		log.Fatalf("Failed to match %q: %v", globPattern, err)
+	}
+
+	for _, match := range matches {
+		if err := os.RemoveAll(match); err != nil {
+			log.Printf("Failed to remove %q: %v", match, err)
+		}
+	}
+}
+
+func ExampleCreateTemp() {
+	f, err := os.CreateTemp("", "example")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove(f.Name()) // clean up
+
+	if _, err := f.Write([]byte("content")); err != nil {
+		log.Fatal(err)
+	}
+	if err := f.Close(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleCreateTemp_suffix() {
+	f, err := os.CreateTemp("", "example.*.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove(f.Name()) // clean up
+
+	if _, err := f.Write([]byte("content")); err != nil {
+		f.Close()
+		log.Fatal(err)
+	}
+	if err := f.Close(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleReadFile() {
+	data, err := os.ReadFile("testdata/hello")
+	if err != nil {
+		log.Fatal(err)
+	}
+	os.Stdout.Write(data)
+
+	// Output:
+	// Hello, Gophers!
+}
+
+func ExampleWriteFile() {
+	err := os.WriteFile("testdata/hello", []byte("Hello, Gophers!"), 0666)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/libgo/go/os/exec.go b/libgo/go/os/exec.go
index cab6a73..edb773a 100644
--- a/libgo/go/os/exec.go
+++ b/libgo/go/os/exec.go
@@ -5,6 +5,7 @@
 package os
 
 import (
+	"errors"
 	"internal/testlog"
 	"runtime"
 	"sync"
@@ -13,6 +14,9 @@ import (
 	"time"
 )
 
+// ErrProcessDone indicates a Process has finished.
+var ErrProcessDone = errors.New("os: process already finished")
+
 // Process stores the information about a process created by StartProcess.
 type Process struct {
 	Pid    int
diff --git a/libgo/go/os/exec/exec_plan9.go b/libgo/go/os/exec/exec_plan9.go
index d90bd04..21ac7b7 100644
--- a/libgo/go/os/exec/exec_plan9.go
+++ b/libgo/go/os/exec/exec_plan9.go
@@ -4,14 +4,14 @@
 
 package exec
 
-import "os"
+import "io/fs"
 
 func init() {
 	skipStdinCopyError = func(err error) bool {
 		// Ignore hungup errors copying to stdin if the program
 		// completed successfully otherwise.
 		// See Issue 35753.
-		pe, ok := err.(*os.PathError)
+		pe, ok := err.(*fs.PathError)
 		return ok &&
 			pe.Op == "write" && pe.Path == "|1" &&
 			pe.Err.Error() == "i/o on hungup channel"
diff --git a/libgo/go/os/exec/exec_test.go b/libgo/go/os/exec/exec_test.go
index dafbc64..8b0c93f 100644
--- a/libgo/go/os/exec/exec_test.go
+++ b/libgo/go/os/exec/exec_test.go
@@ -15,7 +15,6 @@ import (
 	"internal/poll"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -386,7 +385,7 @@ func TestPipeLookPathLeak(t *testing.T) {
 	// Reading /proc/self/fd is more reliable than calling lsof, so try that
 	// first.
 	numOpenFDs := func() (int, []byte, error) {
-		fds, err := ioutil.ReadDir("/proc/self/fd")
+		fds, err := os.ReadDir("/proc/self/fd")
 		if err != nil {
 			return 0, nil, err
 		}
@@ -605,6 +604,10 @@ func TestExtraFiles(t *testing.T) {
 	testenv.MustHaveExec(t)
 	testenv.MustHaveGoBuild(t)
 
+	// This test runs with cgo disabled. External linking needs cgo, so
+	// it doesn't work if external linking is required.
+	testenv.MustInternalLink(t)
+
 	if runtime.GOOS == "windows" {
 		t.Skipf("skipping test on %q", runtime.GOOS)
 	}
@@ -633,7 +636,7 @@ func TestExtraFiles(t *testing.T) {
 	// cgo), to make sure none of that potential C code leaks fds.
 	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
 	// quiet expected TLS handshake error "remote error: bad certificate"
-	ts.Config.ErrorLog = log.New(ioutil.Discard, "", 0)
+	ts.Config.ErrorLog = log.New(io.Discard, "", 0)
 	ts.StartTLS()
 	defer ts.Close()
 	_, err = http.Get(ts.URL)
@@ -641,7 +644,7 @@ func TestExtraFiles(t *testing.T) {
 		t.Errorf("success trying to fetch %s; want an error", ts.URL)
 	}
 
-	tf, err := ioutil.TempFile("", "")
+	tf, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatalf("TempFile: %v", err)
 	}
@@ -687,6 +690,18 @@ func TestExtraFiles(t *testing.T) {
 	c.Stdout = &stdout
 	c.Stderr = &stderr
 	c.ExtraFiles = []*os.File{tf}
+	if runtime.GOOS == "illumos" {
+		// Some facilities in illumos are implemented via access
+		// to /proc by libc; such accesses can briefly occupy a
+		// low-numbered fd.  If this occurs concurrently with the
+		// test that checks for leaked descriptors, the check can
+		// become confused and report a spurious leaked descriptor.
+		// (See issue #42431 for more detailed analysis.)
+		//
+		// Attempt to constrain the use of additional threads in the
+		// child process to make this test less flaky:
+		c.Env = append(os.Environ(), "GOMAXPROCS=1")
+	}
 	err = c.Run()
 	if err != nil {
 		t.Fatalf("Run: %v\n--- stdout:\n%s--- stderr:\n%s", err, stdout.Bytes(), stderr.Bytes())
@@ -826,7 +841,7 @@ func TestHelperProcess(*testing.T) {
 			}
 		}
 	case "stdinClose":
-		b, err := ioutil.ReadAll(os.Stdin)
+		b, err := io.ReadAll(os.Stdin)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 			os.Exit(1)
diff --git a/libgo/go/os/exec/exec_unix.go b/libgo/go/os/exec/exec_unix.go
index 9c3e17d..51c5242 100644
--- a/libgo/go/os/exec/exec_unix.go
+++ b/libgo/go/os/exec/exec_unix.go
@@ -7,7 +7,7 @@
 package exec
 
 import (
-	"os"
+	"io/fs"
 	"syscall"
 )
 
@@ -16,7 +16,7 @@ func init() {
 		// Ignore EPIPE errors copying to stdin if the program
 		// completed successfully otherwise.
 		// See Issue 9173.
-		pe, ok := err.(*os.PathError)
+		pe, ok := err.(*fs.PathError)
 		return ok &&
 			pe.Op == "write" && pe.Path == "|1" &&
 			pe.Err == syscall.EPIPE
diff --git a/libgo/go/os/exec/exec_windows.go b/libgo/go/os/exec/exec_windows.go
index af8cd97..bb937f8 100644
--- a/libgo/go/os/exec/exec_windows.go
+++ b/libgo/go/os/exec/exec_windows.go
@@ -5,7 +5,7 @@
 package exec
 
 import (
-	"os"
+	"io/fs"
 	"syscall"
 )
 
@@ -15,7 +15,7 @@ func init() {
 		// to stdin if the program completed successfully otherwise.
 		// See Issue 20445.
 		const _ERROR_NO_DATA = syscall.Errno(0xe8)
-		pe, ok := err.(*os.PathError)
+		pe, ok := err.(*fs.PathError)
 		return ok &&
 			pe.Op == "write" && pe.Path == "|1" &&
 			(pe.Err == syscall.ERROR_BROKEN_PIPE || pe.Err == _ERROR_NO_DATA)
diff --git a/libgo/go/os/exec/lp_plan9.go b/libgo/go/os/exec/lp_plan9.go
index 5860cbc..e8826a5 100644
--- a/libgo/go/os/exec/lp_plan9.go
+++ b/libgo/go/os/exec/lp_plan9.go
@@ -6,6 +6,7 @@ package exec
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -22,7 +23,7 @@ func findExecutable(file string) error {
 	if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
 		return nil
 	}
-	return os.ErrPermission
+	return fs.ErrPermission
 }
 
 // LookPath searches for an executable named file in the
diff --git a/libgo/go/os/exec/lp_unix.go b/libgo/go/os/exec/lp_unix.go
index 6a5e877..bb5a3ec 100644
--- a/libgo/go/os/exec/lp_unix.go
+++ b/libgo/go/os/exec/lp_unix.go
@@ -8,6 +8,7 @@ package exec
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -24,7 +25,7 @@ func findExecutable(file string) error {
 	if m := d.Mode(); !m.IsDir() && m&0111 != 0 {
 		return nil
 	}
-	return os.ErrPermission
+	return fs.ErrPermission
 }
 
 // LookPath searches for an executable named file in the
diff --git a/libgo/go/os/exec/lp_unix_test.go b/libgo/go/os/exec/lp_unix_test.go
index 5c240b3..23d1506 100644
--- a/libgo/go/os/exec/lp_unix_test.go
+++ b/libgo/go/os/exec/lp_unix_test.go
@@ -7,13 +7,12 @@
 package exec
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 )
 
 func TestLookPathUnixEmptyPath(t *testing.T) {
-	tmp, err := ioutil.TempDir("", "TestLookPathUnixEmptyPath")
+	tmp, err := os.MkdirTemp("", "TestLookPathUnixEmptyPath")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
diff --git a/libgo/go/os/exec/lp_windows.go b/libgo/go/os/exec/lp_windows.go
index 9ea3d76..e7a2cdf 100644
--- a/libgo/go/os/exec/lp_windows.go
+++ b/libgo/go/os/exec/lp_windows.go
@@ -6,6 +6,7 @@ package exec
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -20,7 +21,7 @@ func chkStat(file string) error {
 		return err
 	}
 	if d.IsDir() {
-		return os.ErrPermission
+		return fs.ErrPermission
 	}
 	return nil
 }
@@ -47,7 +48,7 @@ func findExecutable(file string, exts []string) (string, error) {
 			return f, nil
 		}
 	}
-	return "", os.ErrNotExist
+	return "", fs.ErrNotExist
 }
 
 // LookPath searches for an executable named file in the
diff --git a/libgo/go/os/exec/read3.go b/libgo/go/os/exec/read3.go
index 25d732a..8cc24da 100644
--- a/libgo/go/os/exec/read3.go
+++ b/libgo/go/os/exec/read3.go
@@ -15,7 +15,7 @@ package main
 import (
 	"fmt"
 	"internal/poll"
-	"io/ioutil"
+	"io"
 	"os"
 	"os/exec"
 	"runtime"
@@ -24,7 +24,7 @@ import (
 
 func main() {
 	fd3 := os.NewFile(3, "fd3")
-	bs, err := ioutil.ReadAll(fd3)
+	bs, err := io.ReadAll(fd3)
 	if err != nil {
 		fmt.Printf("ReadAll from fd 3: %v\n", err)
 		os.Exit(1)
@@ -56,7 +56,7 @@ func main() {
 			switch runtime.GOOS {
 			case "plan9":
 				args = []string{fmt.Sprintf("/proc/%d/fd", os.Getpid())}
-			case "aix":
+			case "aix", "solaris", "illumos":
 				args = []string{fmt.Sprint(os.Getpid())}
 			default:
 				args = []string{"-p", fmt.Sprint(os.Getpid())}
@@ -71,6 +71,8 @@ func main() {
 				ofcmd = "/bin/cat"
 			case "aix":
 				ofcmd = "procfiles"
+			case "solaris", "illumos":
+				ofcmd = "pfiles"
 			}
 
 			cmd := exec.Command(ofcmd, args...)
diff --git a/libgo/go/os/exec_plan9.go b/libgo/go/os/exec_plan9.go
index b0abf74..8580153 100644
--- a/libgo/go/os/exec_plan9.go
+++ b/libgo/go/os/exec_plan9.go
@@ -5,7 +5,6 @@
 package os
 
 import (
-	"errors"
 	"runtime"
 	"syscall"
 	"time"
@@ -34,7 +33,7 @@ func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err e
 
 	pid, h, e := syscall.StartProcess(name, argv, sysattr)
 	if e != nil {
-		return nil, &PathError{"fork/exec", name, e}
+		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
 	}
 
 	return newProcess(pid, h), nil
@@ -52,7 +51,7 @@ func (p *Process) writeProcFile(file string, data string) error {
 
 func (p *Process) signal(sig Signal) error {
 	if p.done() {
-		return errors.New("os: process already finished")
+		return ErrProcessDone
 	}
 	if e := p.writeProcFile("note", sig.String()); e != nil {
 		return NewSyscallError("signal", e)
diff --git a/libgo/go/os/exec_posix.go b/libgo/go/os/exec_posix.go
index dc9947c..aa8dfe0 100644
--- a/libgo/go/os/exec_posix.go
+++ b/libgo/go/os/exec_posix.go
@@ -56,7 +56,7 @@ func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err e
 	runtime.KeepAlive(attr)
 
 	if e != nil {
-		return nil, &PathError{"fork/exec", name, e}
+		return nil, &PathError{Op: "fork/exec", Path: name, Err: e}
 	}
 
 	return newProcess(pid, h), nil
diff --git a/libgo/go/os/exec_unix.go b/libgo/go/os/exec_unix.go
index a99b45d..69eb615 100644
--- a/libgo/go/os/exec_unix.go
+++ b/libgo/go/os/exec_unix.go
@@ -59,8 +59,6 @@ func (p *Process) wait() (ps *ProcessState, err error) {
 	return ps, nil
 }
 
-var errFinished = errors.New("os: process already finished")
-
 func (p *Process) signal(sig Signal) error {
 	if p.Pid == -1 {
 		return errors.New("os: process already released")
@@ -71,7 +69,7 @@ func (p *Process) signal(sig Signal) error {
 	p.sigMu.RLock()
 	defer p.sigMu.RUnlock()
 	if p.done() {
-		return errFinished
+		return ErrProcessDone
 	}
 	s, ok := sig.(syscall.Signal)
 	if !ok {
@@ -79,7 +77,7 @@ func (p *Process) signal(sig Signal) error {
 	}
 	if e := syscall.Kill(p.Pid, s); e != nil {
 		if e == syscall.ESRCH {
-			return errFinished
+			return ErrProcessDone
 		}
 		return e
 	}
diff --git a/libgo/go/os/exec_unix_test.go b/libgo/go/os/exec_unix_test.go
new file mode 100644
index 0000000..d942cdb
--- /dev/null
+++ b/libgo/go/os/exec_unix_test.go
@@ -0,0 +1,29 @@
+// Copyright 2020 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_test
+
+import (
+	"internal/testenv"
+	. "os"
+	"testing"
+)
+
+func TestErrProcessDone(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
+	path, err := testenv.GoTool()
+	if err != nil {
+		t.Errorf("finding go tool: %v", err)
+	}
+	p, err := StartProcess(path, []string{"go"}, &ProcAttr{})
+	if err != nil {
+		t.Errorf("starting test process: %v", err)
+	}
+	p.Wait()
+	if got := p.Signal(Kill); got != ErrProcessDone {
+		t.Errorf("got %v want %v", got, ErrProcessDone)
+	}
+}
diff --git a/libgo/go/os/exec_windows.go b/libgo/go/os/exec_windows.go
index 24ddf89..5710401 100644
--- a/libgo/go/os/exec_windows.go
+++ b/libgo/go/os/exec_windows.go
@@ -61,7 +61,7 @@ func (p *Process) signal(sig Signal) error {
 		return syscall.EINVAL
 	}
 	if p.done() {
-		return errors.New("os: process already finished")
+		return ErrProcessDone
 	}
 	if sig == Kill {
 		err := terminateProcess(p.Pid, 1)
diff --git a/libgo/go/os/executable_dragonfly.go b/libgo/go/os/executable_dragonfly.go
new file mode 100644
index 0000000..19c2ae8
--- /dev/null
+++ b/libgo/go/os/executable_dragonfly.go
@@ -0,0 +1,12 @@
+// Copyright 2020 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
+
+// From DragonFly's <sys/sysctl.h>
+const (
+	_CTL_KERN           = 1
+	_KERN_PROC          = 14
+	_KERN_PROC_PATHNAME = 9
+)
diff --git a/libgo/go/os/executable_freebsd.go b/libgo/go/os/executable_freebsd.go
index ccaf8e6..95f1a93 100644
--- a/libgo/go/os/executable_freebsd.go
+++ b/libgo/go/os/executable_freebsd.go
@@ -1,33 +1,12 @@
-// Copyright 2016 The Go Authors. All rights reserved.
+// Copyright 2020 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"
-	"unsafe"
+// From FreeBSD's <sys/sysctl.h>
+const (
+	_CTL_KERN           = 1
+	_KERN_PROC          = 14
+	_KERN_PROC_PATHNAME = 12
 )
-
-func executable() (string, error) {
-	mib := [4]int32{1 /* CTL_KERN */, 14 /* KERN_PROC */, 12 /* KERN_PROC_PATHNAME */, -1}
-
-	n := uintptr(0)
-	// get length
-	_, _, err := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, 0, uintptr(unsafe.Pointer(&n)), 0, 0)
-	if err != 0 {
-		return "", err
-	}
-	if n == 0 { // shouldn't happen
-		return "", nil
-	}
-	buf := make([]byte, n)
-	_, _, err = syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&n)), 0, 0)
-	if err != 0 {
-		return "", err
-	}
-	if n == 0 { // shouldn't happen
-		return "", nil
-	}
-	return string(buf[:n-1]), nil
-}
diff --git a/libgo/go/os/executable_procfs.go b/libgo/go/os/executable_procfs.go
index d2d2e5a..989a220 100644
--- a/libgo/go/os/executable_procfs.go
+++ b/libgo/go/os/executable_procfs.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 hurd linux netbsd dragonfly js,wasm
+// +build hurd linux netbsd js,wasm
 
 package os
 
@@ -23,8 +23,6 @@ var executablePath, executablePathErr = func() (string, error) {
 		procfn = "/proc/self/exe"
 	case "netbsd":
 		procfn = "/proc/curproc/exe"
-	case "dragonfly":
-		procfn = "/proc/curproc/file"
 	}
 	return Readlink(procfn)
 }()
diff --git a/libgo/go/os/executable_sysctl.go b/libgo/go/os/executable_sysctl.go
new file mode 100644
index 0000000..f9a4b18
--- /dev/null
+++ b/libgo/go/os/executable_sysctl.go
@@ -0,0 +1,35 @@
+// Copyright 2016 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 freebsd dragonfly
+
+package os
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func executable() (string, error) {
+	mib := [4]int32{_CTL_KERN, _KERN_PROC, _KERN_PROC_PATHNAME, -1}
+
+	n := uintptr(0)
+	// get length
+	_, _, err := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, 0, uintptr(unsafe.Pointer(&n)), 0, 0)
+	if err != 0 {
+		return "", err
+	}
+	if n == 0 { // shouldn't happen
+		return "", nil
+	}
+	buf := make([]byte, n)
+	_, _, err = syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&n)), 0, 0)
+	if err != 0 {
+		return "", err
+	}
+	if n == 0 { // shouldn't happen
+		return "", nil
+	}
+	return string(buf[:n-1]), nil
+}
diff --git a/libgo/go/os/export_test.go b/libgo/go/os/export_test.go
index 812432c..f3cb1a2 100644
--- a/libgo/go/os/export_test.go
+++ b/libgo/go/os/export_test.go
@@ -9,3 +9,5 @@ package os
 var Atime = atime
 var LstatP = &lstat
 var ErrWriteAtInAppendMode = errWriteAtInAppendMode
+var TestingForceReadDirLstat = &testingForceReadDirLstat
+var ErrPatternHasSeparator = errPatternHasSeparator
diff --git a/libgo/go/os/fifo_test.go b/libgo/go/os/fifo_test.go
index 3041dcf..2439192 100644
--- a/libgo/go/os/fifo_test.go
+++ b/libgo/go/os/fifo_test.go
@@ -11,7 +11,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -31,7 +30,7 @@ func TestFifoEOF(t *testing.T) {
 		t.Skip("skipping on OpenBSD; issue 25877")
 	}
 
-	dir, err := ioutil.TempDir("", "TestFifoEOF")
+	dir, err := os.MkdirTemp("", "TestFifoEOF")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go
index a2b71cb..416bc0e 100644
--- a/libgo/go/os/file.go
+++ b/libgo/go/os/file.go
@@ -45,6 +45,7 @@ import (
 	"internal/poll"
 	"internal/testlog"
 	"io"
+	"io/fs"
 	"runtime"
 	"syscall"
 	"time"
@@ -127,7 +128,7 @@ func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
 	}
 
 	if off < 0 {
-		return 0, &PathError{"readat", f.name, errors.New("negative offset")}
+		return 0, &PathError{Op: "readat", Path: f.name, Err: errors.New("negative offset")}
 	}
 
 	for len(b) > 0 {
@@ -203,7 +204,7 @@ func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
 	}
 
 	if off < 0 {
-		return 0, &PathError{"writeat", f.name, errors.New("negative offset")}
+		return 0, &PathError{Op: "writeat", Path: f.name, Err: errors.New("negative offset")}
 	}
 
 	for len(b) > 0 {
@@ -253,12 +254,15 @@ func (f *File) WriteString(s string) (n int, err error) {
 // If there is an error, it will be of type *PathError.
 func Mkdir(name string, perm FileMode) error {
 	if runtime.GOOS == "windows" && isWindowsNulName(name) {
-		return &PathError{"mkdir", name, syscall.ENOTDIR}
+		return &PathError{Op: "mkdir", Path: name, Err: syscall.ENOTDIR}
 	}
-	e := syscall.Mkdir(fixLongPath(name), syscallMode(perm))
+	longName := fixLongPath(name)
+	e := ignoringEINTR(func() error {
+		return syscall.Mkdir(longName, syscallMode(perm))
+	})
 
 	if e != nil {
-		return &PathError{"mkdir", name, e}
+		return &PathError{Op: "mkdir", Path: name, Err: e}
 	}
 
 	// mkdir(2) itself won't handle the sticky bit on *BSD and Solaris
@@ -288,7 +292,7 @@ func setStickyBit(name string) error {
 func Chdir(dir string) error {
 	if e := syscall.Chdir(dir); e != nil {
 		testlog.Open(dir) // observe likely non-existent directory
-		return &PathError{"chdir", dir, e}
+		return &PathError{Op: "chdir", Path: dir, Err: e}
 	}
 	if log := testlog.Logger(); log != nil {
 		wd, err := Getwd()
@@ -363,7 +367,7 @@ func (f *File) wrapErr(op string, err error) error {
 	if err == poll.ErrFileClosing {
 		err = ErrClosed
 	}
-	return &PathError{op, f.name, err}
+	return &PathError{Op: op, Path: f.name, Err: err}
 }
 
 // TempDir returns the default directory to use for temporary files.
@@ -402,7 +406,7 @@ func UserCacheDir() (string, error) {
 			return "", errors.New("%LocalAppData% is not defined")
 		}
 
-	case "darwin":
+	case "darwin", "ios":
 		dir = Getenv("HOME")
 		if dir == "" {
 			return "", errors.New("$HOME is not defined")
@@ -453,7 +457,7 @@ func UserConfigDir() (string, error) {
 			return "", errors.New("%AppData% is not defined")
 		}
 
-	case "darwin":
+	case "darwin", "ios":
 		dir = Getenv("HOME")
 		if dir == "" {
 			return "", errors.New("$HOME is not defined")
@@ -501,10 +505,8 @@ func UserHomeDir() (string, error) {
 	switch runtime.GOOS {
 	case "android":
 		return "/sdcard", nil
-	case "darwin":
-		if runtime.GOARCH == "arm64" {
-			return "/", nil
-		}
+	case "ios":
+		return "/", nil
 	}
 	return "", errors.New(enverr + " is not defined")
 }
@@ -605,3 +607,88 @@ func isWindowsNulName(name string) bool {
 	}
 	return true
 }
+
+// DirFS returns a file system (an fs.FS) for the tree of files rooted at the directory dir.
+//
+// Note that DirFS("/prefix") only guarantees that the Open calls it makes to the
+// operating system will begin with "/prefix": DirFS("/prefix").Open("file") is the
+// same as os.Open("/prefix/file"). So if /prefix/file is a symbolic link pointing outside
+// the /prefix tree, then using DirFS does not stop the access any more than using
+// os.Open does. DirFS is therefore not a general substitute for a chroot-style security
+// mechanism when the directory tree contains arbitrary content.
+func DirFS(dir string) fs.FS {
+	return dirFS(dir)
+}
+
+type dirFS string
+
+func (dir dirFS) Open(name string) (fs.File, error) {
+	if !fs.ValidPath(name) {
+		return nil, &PathError{Op: "open", Path: name, Err: ErrInvalid}
+	}
+	f, err := Open(string(dir) + "/" + name)
+	if err != nil {
+		return nil, err // nil fs.File
+	}
+	return f, nil
+}
+
+// ReadFile reads the named file and returns the contents.
+// A successful call returns err == nil, not err == EOF.
+// Because ReadFile reads the whole file, it does not treat an EOF from Read
+// as an error to be reported.
+func ReadFile(name string) ([]byte, error) {
+	f, err := Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var size int
+	if info, err := f.Stat(); err == nil {
+		size64 := info.Size()
+		if int64(int(size64)) == size64 {
+			size = int(size64)
+		}
+	}
+	size++ // one byte for final read at EOF
+
+	// If a file claims a small size, read at least 512 bytes.
+	// In particular, files in Linux's /proc claim size 0 but
+	// then do not work right if read in small pieces,
+	// so an initial read of 1 byte would not work correctly.
+	if size < 512 {
+		size = 512
+	}
+
+	data := make([]byte, 0, size)
+	for {
+		if len(data) >= cap(data) {
+			d := append(data[:cap(data)], 0)
+			data = d[:len(data)]
+		}
+		n, err := f.Read(data[len(data):cap(data)])
+		data = data[:len(data)+n]
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			return data, err
+		}
+	}
+}
+
+// WriteFile writes data to the named file, creating it if necessary.
+// If the file does not exist, WriteFile creates it with permissions perm (before umask);
+// otherwise WriteFile truncates it before writing, without changing permissions.
+func WriteFile(name string, data []byte, perm FileMode) error {
+	f, err := OpenFile(name, O_WRONLY|O_CREATE|O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+	_, err = f.Write(data)
+	if err1 := f.Close(); err1 != nil && err == nil {
+		err = err1
+	}
+	return err
+}
diff --git a/libgo/go/os/file_plan9.go b/libgo/go/os/file_plan9.go
index eb15890..bbc7328 100644
--- a/libgo/go/os/file_plan9.go
+++ b/libgo/go/os/file_plan9.go
@@ -29,8 +29,13 @@ type file struct {
 }
 
 // Fd returns the integer Plan 9 file descriptor referencing the open file.
-// The file descriptor is valid only until f.Close is called or f is garbage collected.
-// On Unix systems this will cause the SetDeadline methods to stop working.
+// If f is closed, the file descriptor becomes invalid.
+// If f is garbage collected, a finalizer may close the file descriptor,
+// making it invalid; see runtime.SetFinalizer for more information on when
+// a finalizer might be run. On Unix systems this will cause the SetDeadline
+// methods to stop working.
+//
+// As an alternative, see the f.SyscallConn method.
 func (f *File) Fd() uintptr {
 	if f == nil {
 		return ^(uintptr(0))
@@ -114,18 +119,18 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 		if IsNotExist(e) && create {
 			fd, e = syscall.Create(name, flag, syscallMode(perm))
 			if e != nil {
-				return nil, &PathError{"create", name, e}
+				return nil, &PathError{Op: "create", Path: name, Err: e}
 			}
 		}
 	}
 
 	if e != nil {
-		return nil, &PathError{"open", name, e}
+		return nil, &PathError{Op: "open", Path: name, Err: e}
 	}
 
 	if append {
 		if _, e = syscall.Seek(fd, 0, io.SeekEnd); e != nil {
-			return nil, &PathError{"seek", name, e}
+			return nil, &PathError{Op: "seek", Path: name, Err: e}
 		}
 	}
 
@@ -149,7 +154,7 @@ func (file *file) close() error {
 	}
 	var err error
 	if e := syscall.Close(file.fd); e != nil {
-		err = &PathError{"close", file.name, e}
+		err = &PathError{Op: "close", Path: file.name, Err: e}
 	}
 	file.fd = badFd // so it can't be closed again
 
@@ -186,10 +191,10 @@ func (f *File) Truncate(size int64) error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"truncate", f.name, err}
+		return &PathError{Op: "truncate", Path: f.name, Err: err}
 	}
 	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
-		return &PathError{"truncate", f.name, err}
+		return &PathError{Op: "truncate", Path: f.name, Err: err}
 	}
 	return nil
 }
@@ -204,7 +209,7 @@ func (f *File) chmod(mode FileMode) error {
 
 	odir, e := dirstat(f)
 	if e != nil {
-		return &PathError{"chmod", f.name, e}
+		return &PathError{Op: "chmod", Path: f.name, Err: e}
 	}
 	d.Null()
 	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
@@ -212,10 +217,10 @@ func (f *File) chmod(mode FileMode) error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"chmod", f.name, err}
+		return &PathError{Op: "chmod", Path: f.name, Err: err}
 	}
 	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
-		return &PathError{"chmod", f.name, err}
+		return &PathError{Op: "chmod", Path: f.name, Err: err}
 	}
 	return nil
 }
@@ -233,10 +238,10 @@ func (f *File) Sync() error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"sync", f.name, err}
+		return &PathError{Op: "sync", Path: f.name, Err: err}
 	}
 	if err = syscall.Fwstat(f.fd, buf[:n]); err != nil {
-		return &PathError{"sync", f.name, err}
+		return &PathError{Op: "sync", Path: f.name, Err: err}
 	}
 	return nil
 }
@@ -309,10 +314,10 @@ func Truncate(name string, size int64) error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"truncate", name, err}
+		return &PathError{Op: "truncate", Path: name, Err: err}
 	}
 	if err = syscall.Wstat(name, buf[:n]); err != nil {
-		return &PathError{"truncate", name, err}
+		return &PathError{Op: "truncate", Path: name, Err: err}
 	}
 	return nil
 }
@@ -321,7 +326,7 @@ func Truncate(name string, size int64) error {
 // If there is an error, it will be of type *PathError.
 func Remove(name string) error {
 	if e := syscall.Remove(name); e != nil {
-		return &PathError{"remove", name, e}
+		return &PathError{Op: "remove", Path: name, Err: e}
 	}
 	return nil
 }
@@ -384,7 +389,7 @@ func chmod(name string, mode FileMode) error {
 
 	odir, e := dirstat(name)
 	if e != nil {
-		return &PathError{"chmod", name, e}
+		return &PathError{Op: "chmod", Path: name, Err: e}
 	}
 	d.Null()
 	d.Mode = odir.Mode&^chmodMask | syscallMode(mode)&chmodMask
@@ -392,10 +397,10 @@ func chmod(name string, mode FileMode) error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"chmod", name, err}
+		return &PathError{Op: "chmod", Path: name, Err: err}
 	}
 	if err = syscall.Wstat(name, buf[:n]); err != nil {
-		return &PathError{"chmod", name, err}
+		return &PathError{Op: "chmod", Path: name, Err: err}
 	}
 	return nil
 }
@@ -416,10 +421,10 @@ func Chtimes(name string, atime time.Time, mtime time.Time) error {
 	var buf [syscall.STATFIXLEN]byte
 	n, err := d.Marshal(buf[:])
 	if err != nil {
-		return &PathError{"chtimes", name, err}
+		return &PathError{Op: "chtimes", Path: name, Err: err}
 	}
 	if err = syscall.Wstat(name, buf[:n]); err != nil {
-		return &PathError{"chtimes", name, err}
+		return &PathError{Op: "chtimes", Path: name, Err: err}
 	}
 	return nil
 }
@@ -453,7 +458,7 @@ func Symlink(oldname, newname string) error {
 // Readlink returns the destination of the named symbolic link.
 // If there is an error, it will be of type *PathError.
 func Readlink(name string) (string, error) {
-	return "", &PathError{"readlink", name, syscall.EPLAN9}
+	return "", &PathError{Op: "readlink", Path: name, Err: syscall.EPLAN9}
 }
 
 // Chown changes the numeric uid and gid of the named file.
@@ -464,14 +469,14 @@ func Readlink(name string) (string, error) {
 // On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or
 // EPLAN9 error, wrapped in *PathError.
 func Chown(name string, uid, gid int) error {
-	return &PathError{"chown", name, syscall.EPLAN9}
+	return &PathError{Op: "chown", Path: name, Err: syscall.EPLAN9}
 }
 
 // Lchown changes the numeric uid and gid of the named file.
 // If the file is a symbolic link, it changes the uid and gid of the link itself.
 // If there is an error, it will be of type *PathError.
 func Lchown(name string, uid, gid int) error {
-	return &PathError{"lchown", name, syscall.EPLAN9}
+	return &PathError{Op: "lchown", Path: name, Err: syscall.EPLAN9}
 }
 
 // Chown changes the numeric uid and gid of the named file.
@@ -480,7 +485,7 @@ func (f *File) Chown(uid, gid int) error {
 	if f == nil {
 		return ErrInvalid
 	}
-	return &PathError{"chown", f.name, syscall.EPLAN9}
+	return &PathError{Op: "chown", Path: f.name, Err: syscall.EPLAN9}
 }
 
 func tempDir() string {
@@ -500,7 +505,7 @@ func (f *File) Chdir() error {
 		return err
 	}
 	if e := syscall.Fchdir(f.fd); e != nil {
-		return &PathError{"chdir", f.name, e}
+		return &PathError{Op: "chdir", Path: f.name, Err: e}
 	}
 	return nil
 }
@@ -536,7 +541,7 @@ func (f *File) checkValid(op string) error {
 		return ErrInvalid
 	}
 	if f.fd == badFd {
-		return &PathError{op, f.name, ErrClosed}
+		return &PathError{Op: op, Path: f.name, Err: ErrClosed}
 	}
 	return nil
 }
@@ -558,3 +563,7 @@ func (c *rawConn) Write(f func(uintptr) bool) error {
 func newRawConn(file *File) (*rawConn, error) {
 	return nil, syscall.EPLAN9
 }
+
+func ignoringEINTR(fn func() error) error {
+	return fn()
+}
diff --git a/libgo/go/os/file_posix.go b/libgo/go/os/file_posix.go
index ee0728b..95bf9e7 100644
--- a/libgo/go/os/file_posix.go
+++ b/libgo/go/os/file_posix.go
@@ -76,8 +76,12 @@ func syscallMode(i FileMode) (o uint32) {
 
 // See docs in file.go:Chmod.
 func chmod(name string, mode FileMode) error {
-	if e := syscall.Chmod(fixLongPath(name), syscallMode(mode)); e != nil {
-		return &PathError{"chmod", name, e}
+	longName := fixLongPath(name)
+	e := ignoringEINTR(func() error {
+		return syscall.Chmod(longName, syscallMode(mode))
+	})
+	if e != nil {
+		return &PathError{Op: "chmod", Path: name, Err: e}
 	}
 	return nil
 }
@@ -101,8 +105,11 @@ func (f *File) chmod(mode FileMode) error {
 // On Windows or Plan 9, Chown always returns the syscall.EWINDOWS or
 // EPLAN9 error, wrapped in *PathError.
 func Chown(name string, uid, gid int) error {
-	if e := syscall.Chown(name, uid, gid); e != nil {
-		return &PathError{"chown", name, e}
+	e := ignoringEINTR(func() error {
+		return syscall.Chown(name, uid, gid)
+	})
+	if e != nil {
+		return &PathError{Op: "chown", Path: name, Err: e}
 	}
 	return nil
 }
@@ -114,8 +121,11 @@ func Chown(name string, uid, gid int) error {
 // On Windows, it always returns the syscall.EWINDOWS error, wrapped
 // in *PathError.
 func Lchown(name string, uid, gid int) error {
-	if e := syscall.Lchown(name, uid, gid); e != nil {
-		return &PathError{"lchown", name, e}
+	e := ignoringEINTR(func() error {
+		return syscall.Lchown(name, uid, gid)
+	})
+	if e != nil {
+		return &PathError{Op: "lchown", Path: name, Err: e}
 	}
 	return nil
 }
@@ -172,7 +182,7 @@ func Chtimes(name string, atime time.Time, mtime time.Time) error {
 	utimes[0] = syscall.NsecToTimespec(atime.UnixNano())
 	utimes[1] = syscall.NsecToTimespec(mtime.UnixNano())
 	if e := syscall.UtimesNano(fixLongPath(name), utimes[0:]); e != nil {
-		return &PathError{"chtimes", name, e}
+		return &PathError{Op: "chtimes", Path: name, Err: e}
 	}
 	return nil
 }
@@ -222,3 +232,19 @@ func (f *File) checkValid(op string) error {
 	}
 	return nil
 }
+
+// ignoringEINTR makes a function call and repeats it if it returns an
+// EINTR error. This appears to be required even though we install all
+// signal handlers with SA_RESTART: see #22838, #38033, #38836, #40846.
+// Also #20400 and #36644 are issues in which a signal handler is
+// installed without setting SA_RESTART. None of these are the common case,
+// but there are enough of them that it seems that we can't avoid
+// an EINTR loop.
+func ignoringEINTR(fn func() error) error {
+	for {
+		err := fn()
+		if err != syscall.EINTR {
+			return err
+		}
+	}
+}
diff --git a/libgo/go/os/file_unix.go b/libgo/go/os/file_unix.go
index aed7713..8315887 100644
--- a/libgo/go/os/file_unix.go
+++ b/libgo/go/os/file_unix.go
@@ -9,7 +9,6 @@ package os
 import (
 	"internal/poll"
 	"internal/syscall/unix"
-	"io"
 	"runtime"
 	"syscall"
 )
@@ -39,7 +38,9 @@ func rename(oldname, newname string) error {
 			return &LinkError{"rename", oldname, newname, syscall.EEXIST}
 		}
 	}
-	err = syscall.Rename(oldname, newname)
+	err = ignoringEINTR(func() error {
+		return syscall.Rename(oldname, newname)
+	})
 	if err != nil {
 		return &LinkError{"rename", oldname, newname, err}
 	}
@@ -60,8 +61,13 @@ type file struct {
 }
 
 // Fd returns the integer Unix file descriptor referencing the open file.
-// The file descriptor is valid only until f.Close is called or f is garbage collected.
-// On Unix systems this will cause the SetDeadline methods to stop working.
+// If f is closed, the file descriptor becomes invalid.
+// If f is garbage collected, a finalizer may close the file descriptor,
+// making it invalid; see runtime.SetFinalizer for more information on when
+// a finalizer might be run. On Unix systems this will cause the SetDeadline
+// methods to stop working.
+//
+// As an alternative, see the f.SyscallConn method.
 func (f *File) Fd() uintptr {
 	if f == nil {
 		return ^(uintptr(0))
@@ -127,9 +133,11 @@ func newFile(fd uintptr, name string, kind newFileKind) *File {
 	// used with kqueue.
 	if kind == kindOpenFile {
 		switch runtime.GOOS {
-		case "darwin", "dragonfly", "freebsd", "netbsd", "openbsd":
+		case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd":
 			var st syscall.Stat_t
-			err := syscall.Fstat(fdi, &st)
+			err := ignoringEINTR(func() error {
+				return syscall.Fstat(fdi, &st)
+			})
 			typ := st.Mode & syscall.S_IFMT
 			// Don't try to use kqueue with regular files on *BSDs.
 			// On FreeBSD a regular file is always
@@ -146,7 +154,7 @@ func newFile(fd uintptr, name string, kind newFileKind) *File {
 			// 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" && typ == syscall.S_IFIFO {
+			if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
 				pollable = false
 			}
 		}
@@ -173,7 +181,6 @@ func newFile(fd uintptr, name string, kind newFileKind) *File {
 
 // Auxiliary information if the File describes a directory
 type dirInfo struct {
-	buf []byte       // buffer for directory I/O
 	dir *syscall.DIR // from opendir
 }
 
@@ -222,7 +229,7 @@ func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
 			continue
 		}
 
-		return nil, &PathError{"open", name, e}
+		return nil, &PathError{Op: "open", Path: name, Err: e}
 	}
 
 	// open(2) itself won't handle the sticky bit on *BSD and Solaris
@@ -251,7 +258,7 @@ func (file *file) close() error {
 		if e == poll.ErrFileClosing {
 			e = ErrClosed
 		}
-		err = &PathError{"close", file.name, e}
+		err = &PathError{Op: "close", Path: file.name, Err: e}
 	}
 
 	// no need for a finalizer anymore
@@ -279,8 +286,11 @@ func (f *File) seek(offset int64, whence int) (ret int64, err error) {
 // If the file is a symbolic link, it changes the size of the link's target.
 // If there is an error, it will be of type *PathError.
 func Truncate(name string, size int64) error {
-	if e := syscall.Truncate(name, size); e != nil {
-		return &PathError{"truncate", name, e}
+	e := ignoringEINTR(func() error {
+		return syscall.Truncate(name, size)
+	})
+	if e != nil {
+		return &PathError{Op: "truncate", Path: name, Err: e}
 	}
 	return nil
 }
@@ -292,11 +302,15 @@ func Remove(name string) error {
 	// whether name is a file or directory.
 	// Try both: it is cheaper on average than
 	// doing a Stat plus the right one.
-	e := syscall.Unlink(name)
+	e := ignoringEINTR(func() error {
+		return syscall.Unlink(name)
+	})
 	if e == nil {
 		return nil
 	}
-	e1 := syscall.Rmdir(name)
+	e1 := ignoringEINTR(func() error {
+		return syscall.Rmdir(name)
+	})
 	if e1 == nil {
 		return nil
 	}
@@ -313,7 +327,7 @@ func Remove(name string) error {
 	if e1 != syscall.ENOTDIR {
 		e = e1
 	}
-	return &PathError{"remove", name, e}
+	return &PathError{Op: "remove", Path: name, Err: e}
 }
 
 func tempDir() string {
@@ -331,7 +345,9 @@ func tempDir() string {
 // Link creates newname as a hard link to the oldname file.
 // If there is an error, it will be of type *LinkError.
 func Link(oldname, newname string) error {
-	e := syscall.Link(oldname, newname)
+	e := ignoringEINTR(func() error {
+		return syscall.Link(oldname, newname)
+	})
 	if e != nil {
 		return &LinkError{"link", oldname, newname, e}
 	}
@@ -341,55 +357,77 @@ func Link(oldname, newname string) error {
 // Symlink creates newname as a symbolic link to oldname.
 // If there is an error, it will be of type *LinkError.
 func Symlink(oldname, newname string) error {
-	e := syscall.Symlink(oldname, newname)
+	e := ignoringEINTR(func() error {
+		return syscall.Symlink(oldname, newname)
+	})
 	if e != nil {
 		return &LinkError{"symlink", oldname, newname, e}
 	}
 	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
-}
-
 // Readlink returns the destination of the named symbolic link.
 // If there is an error, it will be of type *PathError.
 func Readlink(name string) (string, error) {
 	for len := 128; ; len *= 2 {
 		b := make([]byte, len)
-		n, e := fixCount(syscall.Readlink(name, b))
+		var (
+			n int
+			e error
+		)
+		for {
+			n, e = fixCount(syscall.Readlink(name, b))
+			if e != syscall.EINTR {
+				break
+			}
+		}
 		// buffer too small
 		if runtime.GOOS == "aix" && e == syscall.ERANGE {
 			continue
 		}
 		if e != nil {
-			return "", &PathError{"readlink", name, e}
+			return "", &PathError{Op: "readlink", Path: name, Err: e}
 		}
 		if n < len {
 			return string(b[0:n]), nil
 		}
 	}
 }
+
+type unixDirent struct {
+	parent string
+	name   string
+	typ    FileMode
+	info   FileInfo
+}
+
+func (d *unixDirent) Name() string   { return d.name }
+func (d *unixDirent) IsDir() bool    { return d.typ.IsDir() }
+func (d *unixDirent) Type() FileMode { return d.typ }
+
+func (d *unixDirent) Info() (FileInfo, error) {
+	if d.info != nil {
+		return d.info, nil
+	}
+	return lstat(d.parent + "/" + d.name)
+}
+
+func newUnixDirent(parent, name string, typ FileMode) (DirEntry, error) {
+	ude := &unixDirent{
+		parent: parent,
+		name:   name,
+		typ:    typ,
+	}
+	if typ != ^FileMode(0) && !testingForceReadDirLstat {
+		return ude, nil
+	}
+
+	info, err := lstat(parent + "/" + name)
+	if err != nil {
+		return nil, err
+	}
+
+	ude.typ = info.Mode().Type()
+	ude.info = info
+	return ude, nil
+}
diff --git a/libgo/go/os/getwd.go b/libgo/go/os/getwd.go
index 6d25466..90604cf 100644
--- a/libgo/go/os/getwd.go
+++ b/libgo/go/os/getwd.go
@@ -15,10 +15,6 @@ var getwdCache struct {
 	dir string
 }
 
-// useSyscallwd determines whether to use the return value of
-// syscall.Getwd based on its error.
-var useSyscallwd = func(error) bool { return true }
-
 // Getwd returns a rooted path name corresponding to the
 // current directory. If the current directory can be
 // reached via multiple paths (due to symbolic links),
@@ -45,10 +41,17 @@ func Getwd() (dir string, err error) {
 	// If the operating system provides a Getwd call, use it.
 	// Otherwise, we're trying to find our way back to ".".
 	if syscall.ImplementsGetwd {
-		s, e := syscall.Getwd()
-		if useSyscallwd(e) {
-			return s, NewSyscallError("getwd", e)
+		var (
+			s string
+			e error
+		)
+		for {
+			s, e = syscall.Getwd()
+			if e != syscall.EINTR {
+				break
+			}
 		}
+		return s, NewSyscallError("getwd", e)
 	}
 
 	// Apply same kludge but to cached dir instead of $PWD.
@@ -103,10 +106,10 @@ func Getwd() (dir string, err error) {
 
 	Found:
 		pd, err := fd.Stat()
+		fd.Close()
 		if err != nil {
 			return "", err
 		}
-		fd.Close()
 		if SameFile(pd, root) {
 			break
 		}
diff --git a/libgo/go/os/getwd_darwin.go b/libgo/go/os/getwd_darwin.go
deleted file mode 100644
index e51ffcd..0000000
--- a/libgo/go/os/getwd_darwin.go
+++ /dev/null
@@ -1,15 +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.
-
-package os
-
-import "syscall"
-
-func init() {
-	useSyscallwd = useSyscallwdDarwin
-}
-
-func useSyscallwdDarwin(err error) bool {
-	return err != syscall.ENOTSUP
-}
diff --git a/libgo/go/os/os_test.go b/libgo/go/os/os_test.go
index 8a2f917..ccef141 100644
--- a/libgo/go/os/os_test.go
+++ b/libgo/go/os/os_test.go
@@ -11,7 +11,7 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"os"
 	. "os"
 	osexec "os/exec"
 	"path/filepath"
@@ -23,6 +23,7 @@ import (
 	"sync"
 	"syscall"
 	"testing"
+	"testing/fstest"
 	"time"
 )
 
@@ -50,7 +51,7 @@ var sysdir = func() *sysDir {
 				"libpowermanager.so",
 			},
 		}
-	case "darwin":
+	case "darwin", "ios":
 		switch runtime.GOARCH {
 		case "arm64":
 			wd, err := syscall.Getwd()
@@ -142,7 +143,7 @@ func localTmp() string {
 	switch runtime.GOOS {
 	case "android", "windows":
 		return TempDir()
-	case "darwin":
+	case "darwin", "ios":
 		switch runtime.GOARCH {
 		case "arm64":
 			return TempDir()
@@ -152,7 +153,7 @@ func localTmp() string {
 }
 
 func newFile(testName string, t *testing.T) (f *File) {
-	f, err := ioutil.TempFile(localTmp(), "_Go_"+testName)
+	f, err := os.CreateTemp(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempFile %s: %s", testName, err)
 	}
@@ -160,7 +161,7 @@ func newFile(testName string, t *testing.T) (f *File) {
 }
 
 func newDir(testName string, t *testing.T) (name string) {
-	name, err := ioutil.TempDir(localTmp(), "_Go_"+testName)
+	name, err := os.MkdirTemp(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempDir %s: %s", testName, err)
 	}
@@ -307,25 +308,29 @@ func testReaddirnames(dir string, contents []string, t *testing.T) {
 	defer file.Close()
 	s, err2 := file.Readdirnames(-1)
 	if err2 != nil {
-		t.Fatalf("readdirnames %q failed: %v", dir, err2)
+		t.Fatalf("Readdirnames %q failed: %v", dir, err2)
 	}
 	for _, m := range contents {
 		found := false
 		for _, n := range s {
 			if n == "." || n == ".." {
-				t.Errorf("got %s in directory", n)
+				t.Errorf("got %q in directory", n)
 			}
-			if equal(m, n) {
-				if found {
-					t.Error("present twice:", m)
-				}
-				found = true
+			if !equal(m, n) {
+				continue
+			}
+			if found {
+				t.Error("present twice:", m)
 			}
+			found = true
 		}
 		if !found {
 			t.Error("could not find", m)
 		}
 	}
+	if s == nil {
+		t.Error("Readdirnames returned nil instead of empty slice")
+	}
 }
 
 func testReaddir(dir string, contents []string, t *testing.T) {
@@ -336,32 +341,98 @@ func testReaddir(dir string, contents []string, t *testing.T) {
 	defer file.Close()
 	s, err2 := file.Readdir(-1)
 	if err2 != nil {
-		t.Fatalf("readdir %q failed: %v", dir, err2)
+		t.Fatalf("Readdir %q failed: %v", dir, err2)
 	}
 	for _, m := range contents {
 		found := false
 		for _, n := range s {
-			if equal(m, n.Name()) {
-				if found {
-					t.Error("present twice:", m)
-				}
-				found = true
+			if n.Name() == "." || n.Name() == ".." {
+				t.Errorf("got %q in directory", n.Name())
 			}
+			if !equal(m, n.Name()) {
+				continue
+			}
+			if found {
+				t.Error("present twice:", m)
+			}
+			found = true
 		}
 		if !found {
 			t.Error("could not find", m)
 		}
 	}
+	if s == nil {
+		t.Error("Readdir returned nil instead of empty slice")
+	}
 }
 
-func TestReaddirnames(t *testing.T) {
+func testReadDir(dir string, contents []string, t *testing.T) {
+	file, err := Open(dir)
+	if err != nil {
+		t.Fatalf("open %q failed: %v", dir, err)
+	}
+	defer file.Close()
+	s, err2 := file.ReadDir(-1)
+	if err2 != nil {
+		t.Fatalf("ReadDir %q failed: %v", dir, err2)
+	}
+	for _, m := range contents {
+		found := false
+		for _, n := range s {
+			if n.Name() == "." || n.Name() == ".." {
+				t.Errorf("got %q in directory", n)
+			}
+			if !equal(m, n.Name()) {
+				continue
+			}
+			if found {
+				t.Error("present twice:", m)
+			}
+			found = true
+			lstat, err := Lstat(dir + "/" + m)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if n.IsDir() != lstat.IsDir() {
+				t.Errorf("%s: IsDir=%v, want %v", m, n.IsDir(), lstat.IsDir())
+			}
+			if n.Type() != lstat.Mode().Type() {
+				t.Errorf("%s: IsDir=%v, want %v", m, n.Type(), lstat.Mode().Type())
+			}
+			info, err := n.Info()
+			if err != nil {
+				t.Errorf("%s: Info: %v", m, err)
+				continue
+			}
+			if !SameFile(info, lstat) {
+				t.Errorf("%s: Info: SameFile(info, lstat) = false", m)
+			}
+		}
+		if !found {
+			t.Error("could not find", m)
+		}
+	}
+	if s == nil {
+		t.Error("ReadDir returned nil instead of empty slice")
+	}
+}
+
+func TestFileReaddirnames(t *testing.T) {
 	testReaddirnames(".", dot, t)
 	testReaddirnames(sysdir.name, sysdir.files, t)
+	testReaddirnames(t.TempDir(), nil, t)
 }
 
-func TestReaddir(t *testing.T) {
+func TestFileReaddir(t *testing.T) {
 	testReaddir(".", dot, t)
 	testReaddir(sysdir.name, sysdir.files, t)
+	testReaddir(t.TempDir(), nil, t)
+}
+
+func TestFileReadDir(t *testing.T) {
+	testReadDir(".", dot, t)
+	testReadDir(sysdir.name, sysdir.files, t)
+	testReadDir(t.TempDir(), nil, t)
 }
 
 func benchmarkReaddirname(path string, b *testing.B) {
@@ -398,6 +469,23 @@ func benchmarkReaddir(path string, b *testing.B) {
 	b.Logf("benchmarkReaddir %q: %d entries", path, nentries)
 }
 
+func benchmarkReadDir(path string, b *testing.B) {
+	var nentries int
+	for i := 0; i < b.N; i++ {
+		f, err := Open(path)
+		if err != nil {
+			b.Fatalf("open %q failed: %v", path, err)
+		}
+		fs, err := f.ReadDir(-1)
+		f.Close()
+		if err != nil {
+			b.Fatalf("readdir %q failed: %v", path, err)
+		}
+		nentries = len(fs)
+	}
+	b.Logf("benchmarkReadDir %q: %d entries", path, nentries)
+}
+
 func BenchmarkReaddirname(b *testing.B) {
 	benchmarkReaddirname(".", b)
 }
@@ -406,6 +494,10 @@ func BenchmarkReaddir(b *testing.B) {
 	benchmarkReaddir(".", b)
 }
 
+func BenchmarkReadDir(b *testing.B) {
+	benchmarkReadDir(".", b)
+}
+
 func benchmarkStat(b *testing.B, path string) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -479,7 +571,7 @@ func TestReaddirnamesOneAtATime(t *testing.T) {
 	switch runtime.GOOS {
 	case "android":
 		dir = "/system/bin"
-	case "darwin":
+	case "darwin", "ios":
 		switch runtime.GOARCH {
 		case "arm64":
 			wd, err := Getwd()
@@ -522,7 +614,7 @@ func TestReaddirNValues(t *testing.T) {
 	if testing.Short() {
 		t.Skip("test.short; skipping")
 	}
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
@@ -545,7 +637,8 @@ func TestReaddirNValues(t *testing.T) {
 		}
 	}
 
-	readDirExpect := func(n, want int, wantErr error) {
+	readdirExpect := func(n, want int, wantErr error) {
+		t.Helper()
 		fi, err := d.Readdir(n)
 		if err != wantErr {
 			t.Fatalf("Readdir of %d got error %v, want %v", n, err, wantErr)
@@ -555,7 +648,19 @@ func TestReaddirNValues(t *testing.T) {
 		}
 	}
 
-	readDirNamesExpect := func(n, want int, wantErr error) {
+	readDirExpect := func(n, want int, wantErr error) {
+		t.Helper()
+		de, err := d.ReadDir(n)
+		if err != wantErr {
+			t.Fatalf("ReadDir of %d got error %v, want %v", n, err, wantErr)
+		}
+		if g, e := len(de), want; g != e {
+			t.Errorf("ReadDir of %d got %d files, want %d", n, g, e)
+		}
+	}
+
+	readdirnamesExpect := func(n, want int, wantErr error) {
+		t.Helper()
 		fi, err := d.Readdirnames(n)
 		if err != wantErr {
 			t.Fatalf("Readdirnames of %d got error %v, want %v", n, err, wantErr)
@@ -565,7 +670,7 @@ func TestReaddirNValues(t *testing.T) {
 		}
 	}
 
-	for _, fn := range []func(int, int, error){readDirExpect, readDirNamesExpect} {
+	for _, fn := range []func(int, int, error){readdirExpect, readdirnamesExpect, readDirExpect} {
 		// Test the slurp case
 		openDir()
 		fn(0, 105, nil)
@@ -608,7 +713,7 @@ func TestReaddirStatFailures(t *testing.T) {
 		// testing it wouldn't work.
 		t.Skipf("skipping test on %v", runtime.GOOS)
 	}
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
@@ -669,7 +774,7 @@ func TestReaddirStatFailures(t *testing.T) {
 
 // Readdir on a regular file should fail.
 func TestReaddirOfFile(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ReaddirOfFile")
+	f, err := os.CreateTemp("", "_Go_ReaddirOfFile")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -686,6 +791,10 @@ func TestReaddirOfFile(t *testing.T) {
 	if err == nil {
 		t.Error("Readdirnames succeeded; want non-nil error")
 	}
+	var pe *PathError
+	if !errors.As(err, &pe) || pe.Path != f.Name() {
+		t.Errorf("Readdirnames returned %q; want a PathError with path %q", err, f.Name())
+	}
 	if len(names) > 0 {
 		t.Errorf("unexpected dir names in regular file: %q", names)
 	}
@@ -756,7 +865,7 @@ func chtmpdir(t *testing.T) func() {
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
@@ -881,12 +990,12 @@ func TestRenameOverwriteDest(t *testing.T) {
 	toData := []byte("to")
 	fromData := []byte("from")
 
-	err := ioutil.WriteFile(to, toData, 0777)
+	err := os.WriteFile(to, toData, 0777)
 	if err != nil {
 		t.Fatalf("write file %q failed: %v", to, err)
 	}
 
-	err = ioutil.WriteFile(from, fromData, 0777)
+	err = os.WriteFile(from, fromData, 0777)
 	if err != nil {
 		t.Fatalf("write file %q failed: %v", from, err)
 	}
@@ -1093,32 +1202,38 @@ func checkMode(t *testing.T, path string, mode FileMode) {
 	if err != nil {
 		t.Fatalf("Stat %q (looking for mode %#o): %s", path, mode, err)
 	}
-	if dir.Mode()&0777 != mode {
+	if dir.Mode()&ModePerm != mode {
 		t.Errorf("Stat %q: mode %#o want %#o", path, dir.Mode(), mode)
 	}
 }
 
 func TestChmod(t *testing.T) {
-	// Chmod is not supported under windows.
-	if runtime.GOOS == "windows" {
-		return
-	}
 	f := newFile("TestChmod", t)
 	defer Remove(f.Name())
 	defer f.Close()
+	// Creation mode is read write
 
-	if err := Chmod(f.Name(), 0456); err != nil {
-		t.Fatalf("chmod %s 0456: %s", f.Name(), err)
+	fm := FileMode(0456)
+	if runtime.GOOS == "windows" {
+		fm = FileMode(0444) // read-only file
 	}
-	checkMode(t, f.Name(), 0456)
+	if err := Chmod(f.Name(), fm); err != nil {
+		t.Fatalf("chmod %s %#o: %s", f.Name(), fm, err)
+	}
+	checkMode(t, f.Name(), fm)
 
-	if err := f.Chmod(0123); err != nil {
-		t.Fatalf("chmod %s 0123: %s", f.Name(), err)
+	fm = FileMode(0123)
+	if runtime.GOOS == "windows" {
+		fm = FileMode(0666) // read-write file
+	}
+	if err := f.Chmod(fm); err != nil {
+		t.Fatalf("chmod %s %#o: %s", f.Name(), fm, err)
 	}
-	checkMode(t, f.Name(), 0123)
+	checkMode(t, f.Name(), fm)
 }
 
 func checkSize(t *testing.T, f *File, size int64) {
+	t.Helper()
 	dir, err := f.Stat()
 	if err != nil {
 		t.Fatalf("Stat %q (looking for size %d): %s", f.Name(), size, err)
@@ -1224,7 +1339,7 @@ func testChtimes(t *testing.T, name string) {
 			// the contents are accessed; also, it is set
 			// whenever mtime is set.
 		case "netbsd":
-			mounts, _ := ioutil.ReadFile("/proc/mounts")
+			mounts, _ := os.ReadFile("/proc/mounts")
 			if strings.Contains(string(mounts), "noatime") {
 				t.Logf("AccessTime didn't go backwards, but see a filesystem mounted noatime; ignoring. Issue 19293.")
 			} else {
@@ -1293,12 +1408,12 @@ func TestChdirAndGetwd(t *testing.T) {
 		dirs = []string{"/system/bin"}
 	case "plan9":
 		dirs = []string{"/", "/usr"}
-	case "darwin":
+	case "darwin", "ios":
 		switch runtime.GOARCH {
 		case "arm64":
 			dirs = nil
 			for _, d := range []string{"d1", "d2"} {
-				dir, err := ioutil.TempDir("", d)
+				dir, err := os.MkdirTemp("", d)
 				if err != nil {
 					t.Fatalf("TempDir: %v", err)
 				}
@@ -1392,7 +1507,7 @@ func TestProgWideChdir(t *testing.T) {
 		c <- true
 		t.Fatalf("Getwd: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		c <- true
 		t.Fatalf("TempDir: %v", err)
@@ -1463,7 +1578,7 @@ func TestSeek(t *testing.T) {
 		off, err := f.Seek(tt.in, tt.whence)
 		if off != tt.out || err != nil {
 			if e, ok := err.(*PathError); ok && e.Err == syscall.EINVAL && tt.out > 1<<32 && runtime.GOOS == "linux" {
-				mounts, _ := ioutil.ReadFile("/proc/mounts")
+				mounts, _ := os.ReadFile("/proc/mounts")
 				if strings.Contains(string(mounts), "reiserfs") {
 					// Reiserfs rejects the big seeks.
 					t.Skipf("skipping test known to fail on reiserfs; https://golang.org/issue/91")
@@ -1566,8 +1681,8 @@ func TestOpenError(t *testing.T) {
 func TestOpenNoName(t *testing.T) {
 	f, err := Open("")
 	if err == nil {
-		t.Fatal(`Open("") succeeded`)
 		f.Close()
+		t.Fatal(`Open("") succeeded`)
 	}
 }
 
@@ -1745,7 +1860,7 @@ func TestWriteAt(t *testing.T) {
 		t.Fatalf("WriteAt 7: %d, %v", n, err)
 	}
 
-	b, err := ioutil.ReadFile(f.Name())
+	b, err := os.ReadFile(f.Name())
 	if err != nil {
 		t.Fatalf("ReadFile %s: %v", f.Name(), err)
 	}
@@ -1793,7 +1908,7 @@ func writeFile(t *testing.T, fname string, flag int, text string) string {
 		t.Fatalf("WriteString: %d, %v", n, err)
 	}
 	f.Close()
-	data, err := ioutil.ReadFile(fname)
+	data, err := os.ReadFile(fname)
 	if err != nil {
 		t.Fatalf("ReadFile: %v", err)
 	}
@@ -1835,7 +1950,7 @@ func TestAppend(t *testing.T) {
 
 func TestStatDirWithTrailingSlash(t *testing.T) {
 	// Create new temporary directory and arrange to clean it up.
-	path, err := ioutil.TempDir("", "_TestStatDirWithSlash_")
+	path, err := os.MkdirTemp("", "_TestStatDirWithSlash_")
 	if err != nil {
 		t.Fatalf("TempDir: %s", err)
 	}
@@ -1977,7 +2092,7 @@ func TestLargeWriteToConsole(t *testing.T) {
 func TestStatDirModeExec(t *testing.T) {
 	const mode = 0111
 
-	path, err := ioutil.TempDir("", "go-build")
+	path, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("Failed to create temp directory: %v", err)
 	}
@@ -2046,7 +2161,7 @@ func TestStatStdin(t *testing.T) {
 func TestStatRelativeSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestStatRelativeSymlink")
+	tmpdir, err := os.MkdirTemp("", "TestStatRelativeSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -2136,8 +2251,8 @@ func TestLongPath(t *testing.T) {
 				t.Fatalf("MkdirAll failed: %v", err)
 			}
 			data := []byte("hello world\n")
-			if err := ioutil.WriteFile(sizedTempDir+"/foo.txt", data, 0644); err != nil {
-				t.Fatalf("ioutil.WriteFile() failed: %v", err)
+			if err := os.WriteFile(sizedTempDir+"/foo.txt", data, 0644); err != nil {
+				t.Fatalf("os.WriteFile() failed: %v", err)
 			}
 			if err := Rename(sizedTempDir+"/foo.txt", sizedTempDir+"/bar.txt"); err != nil {
 				t.Fatalf("Rename failed: %v", err)
@@ -2321,7 +2436,7 @@ func TestRemoveAllRace(t *testing.T) {
 
 	n := runtime.GOMAXPROCS(16)
 	defer runtime.GOMAXPROCS(n)
-	root, err := ioutil.TempDir("", "issue")
+	root, err := os.MkdirTemp("", "issue")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -2427,7 +2542,7 @@ func testDoubleCloseError(t *testing.T, path string) {
 	if err := file.Close(); err == nil {
 		t.Error("second Close did not fail")
 	} else if pe, ok := err.(*PathError); !ok {
-		t.Errorf("second Close returned unexpected error type %T; expected os.PathError", pe)
+		t.Errorf("second Close returned unexpected error type %T; expected fs.PathError", pe)
 	} else if pe.Err != ErrClosed {
 		t.Errorf("second Close returned %q, wanted %q", err, ErrClosed)
 	} else {
@@ -2572,3 +2687,28 @@ func TestOpenFileKeepsPermissions(t *testing.T) {
 		t.Errorf("Stat after OpenFile is %v, should be writable", fi.Mode())
 	}
 }
+
+func TestDirFS(t *testing.T) {
+	if err := fstest.TestFS(DirFS("./signal"), "signal.go", "internal/pty/pty.go"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestReadFileProc(t *testing.T) {
+	// Linux files in /proc report 0 size,
+	// but then if ReadFile reads just a single byte at offset 0,
+	// the read at offset 1 returns EOF instead of more data.
+	// ReadFile has a minimum read size of 512 to work around this,
+	// but test explicitly that it's working.
+	name := "/proc/sys/fs/pipe-max-size"
+	if _, err := Stat(name); err != nil {
+		t.Skip(err)
+	}
+	data, err := ReadFile(name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(data) == 0 || data[len(data)-1] != '\n' {
+		t.Fatalf("read %s: not newline-terminated: %q", name, data)
+	}
+}
diff --git a/libgo/go/os/os_unix_test.go b/libgo/go/os/os_unix_test.go
index 7b6fa0c..9a5d7bf 100644
--- a/libgo/go/os/os_unix_test.go
+++ b/libgo/go/os/os_unix_test.go
@@ -8,7 +8,7 @@ package os_test
 
 import (
 	"io"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -190,7 +190,7 @@ func TestReaddirRemoveRace(t *testing.T) {
 	}
 	dir := newDir("TestReaddirRemoveRace", t)
 	defer RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "some-file"), []byte("hello"), 0644); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "some-file"), []byte("hello"), 0644); err != nil {
 		t.Fatal(err)
 	}
 	d, err := Open(dir)
diff --git a/libgo/go/os/os_windows_test.go b/libgo/go/os/os_windows_test.go
index f03ec75..8d1d1f6 100644
--- a/libgo/go/os/os_windows_test.go
+++ b/libgo/go/os/os_windows_test.go
@@ -12,7 +12,7 @@ import (
 	"internal/syscall/windows/registry"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	osexec "os/exec"
 	"path/filepath"
@@ -30,7 +30,7 @@ import (
 type syscallDescriptor = syscall.Handle
 
 func TestSameWindowsFile(t *testing.T) {
-	temp, err := ioutil.TempDir("", "TestSameWindowsFile")
+	temp, err := os.MkdirTemp("", "TestSameWindowsFile")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -89,7 +89,7 @@ type dirLinkTest struct {
 }
 
 func testDirLinks(t *testing.T, tests []dirLinkTest) {
-	tmpdir, err := ioutil.TempDir("", "testDirLinks")
+	tmpdir, err := os.MkdirTemp("", "testDirLinks")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -114,7 +114,7 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
+	err = os.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -126,7 +126,7 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 			continue
 		}
 
-		data, err := ioutil.ReadFile(filepath.Join(link, "abc"))
+		data, err := os.ReadFile(filepath.Join(link, "abc"))
 		if err != nil {
 			t.Errorf("failed to read abc file: %v", err)
 			continue
@@ -164,11 +164,11 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 			t.Errorf("failed to lstat link %v: %v", link, err)
 			continue
 		}
-		if m := fi2.Mode(); m&os.ModeSymlink == 0 {
+		if m := fi2.Mode(); m&fs.ModeSymlink == 0 {
 			t.Errorf("%q should be a link, but is not (mode=0x%x)", link, uint32(m))
 			continue
 		}
-		if m := fi2.Mode(); m&os.ModeDir != 0 {
+		if m := fi2.Mode(); m&fs.ModeDir != 0 {
 			t.Errorf("%q should be a link, not a directory (mode=0x%x)", link, uint32(m))
 			continue
 		}
@@ -438,7 +438,7 @@ func TestNetworkSymbolicLink(t *testing.T) {
 
 	const _NERR_ServerNotStarted = syscall.Errno(2114)
 
-	dir, err := ioutil.TempDir("", "TestNetworkSymbolicLink")
+	dir, err := os.MkdirTemp("", "TestNetworkSymbolicLink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -599,7 +599,7 @@ func TestStatDir(t *testing.T) {
 }
 
 func TestOpenVolumeName(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestOpenVolumeName")
+	tmpdir, err := os.MkdirTemp("", "TestOpenVolumeName")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -618,7 +618,7 @@ func TestOpenVolumeName(t *testing.T) {
 	want := []string{"file1", "file2", "file3", "gopher.txt"}
 	sort.Strings(want)
 	for _, name := range want {
-		err := ioutil.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
+		err := os.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -642,7 +642,7 @@ func TestOpenVolumeName(t *testing.T) {
 }
 
 func TestDeleteReadOnly(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestDeleteReadOnly")
+	tmpdir, err := os.MkdirTemp("", "TestDeleteReadOnly")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -681,7 +681,7 @@ func TestStatSymlinkLoop(t *testing.T) {
 	defer os.Remove("x")
 
 	_, err = os.Stat("x")
-	if _, ok := err.(*os.PathError); !ok {
+	if _, ok := err.(*fs.PathError); !ok {
 		t.Errorf("expected *PathError, got %T: %v\n", err, err)
 	}
 }
@@ -803,7 +803,7 @@ func compareCommandLineToArgvWithSyscall(t *testing.T, cmd string) {
 }
 
 func TestCmdArgs(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestCmdArgs")
+	tmpdir, err := os.MkdirTemp("", "TestCmdArgs")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -822,7 +822,7 @@ func main() {
 }
 `
 	src := filepath.Join(tmpdir, "main.go")
-	err = ioutil.WriteFile(src, []byte(prog), 0666)
+	err = os.WriteFile(src, []byte(prog), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -970,14 +970,14 @@ func TestSymlinkCreation(t *testing.T) {
 	}
 	t.Parallel()
 
-	temp, err := ioutil.TempDir("", "TestSymlinkCreation")
+	temp, err := os.MkdirTemp("", "TestSymlinkCreation")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(temp)
 
 	dummyFile := filepath.Join(temp, "file")
-	err = ioutil.WriteFile(dummyFile, []byte(""), 0644)
+	err = os.WriteFile(dummyFile, []byte(""), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1206,7 +1206,7 @@ func mklinkd(t *testing.T, link, target string) {
 }
 
 func TestWindowsReadlink(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestWindowsReadlink")
+	tmpdir, err := os.MkdirTemp("", "TestWindowsReadlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1271,7 +1271,7 @@ func TestWindowsReadlink(t *testing.T) {
 	testReadlink(t, "reldirlink", "dir")
 
 	file := filepath.Join(tmpdir, "file")
-	err = ioutil.WriteFile(file, []byte(""), 0666)
+	err = os.WriteFile(file, []byte(""), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1291,9 +1291,9 @@ func TestWindowsReadlink(t *testing.T) {
 // os.Mkdir(os.DevNull) fails.
 func TestMkdirDevNull(t *testing.T) {
 	err := os.Mkdir(os.DevNull, 777)
-	oserr, ok := err.(*os.PathError)
+	oserr, ok := err.(*fs.PathError)
 	if !ok {
-		t.Fatalf("error (%T) is not *os.PathError", err)
+		t.Fatalf("error (%T) is not *fs.PathError", err)
 	}
 	errno, ok := oserr.Err.(syscall.Errno)
 	if !ok {
diff --git a/libgo/go/os/path.go b/libgo/go/os/path.go
index ba43ea3..df87887 100644
--- a/libgo/go/os/path.go
+++ b/libgo/go/os/path.go
@@ -22,7 +22,7 @@ func MkdirAll(path string, perm FileMode) error {
 		if dir.IsDir() {
 			return nil
 		}
-		return &PathError{"mkdir", path, syscall.ENOTDIR}
+		return &PathError{Op: "mkdir", Path: path, Err: syscall.ENOTDIR}
 	}
 
 	// Slow path: make sure parent exists and then call Mkdir for path.
diff --git a/libgo/go/os/path_test.go b/libgo/go/os/path_test.go
index d586daf..b79d958 100644
--- a/libgo/go/os/path_test.go
+++ b/libgo/go/os/path_test.go
@@ -6,7 +6,7 @@ package os_test
 
 import (
 	"internal/testenv"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -78,7 +78,7 @@ func TestMkdirAll(t *testing.T) {
 func TestMkdirAllWithSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "TestMkdirAllWithSymlink-")
+	tmpDir, err := os.MkdirTemp("", "TestMkdirAllWithSymlink-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -107,7 +107,7 @@ func TestMkdirAllAtSlash(t *testing.T) {
 	switch runtime.GOOS {
 	case "android", "plan9", "windows":
 		t.Skipf("skipping on %s", runtime.GOOS)
-	case "darwin":
+	case "darwin", "ios":
 		switch runtime.GOARCH {
 		case "arm64":
 			t.Skipf("skipping on darwin/arm64, mkdir returns EPERM")
diff --git a/libgo/go/os/path_windows_test.go b/libgo/go/os/path_windows_test.go
index 862b404..869db8f 100644
--- a/libgo/go/os/path_windows_test.go
+++ b/libgo/go/os/path_windows_test.go
@@ -5,7 +5,6 @@
 package os_test
 
 import (
-	"io/ioutil"
 	"os"
 	"strings"
 	"syscall"
@@ -48,7 +47,7 @@ func TestFixLongPath(t *testing.T) {
 }
 
 func TestMkdirAllExtendedLength(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "TestMkdirAllExtendedLength")
+	tmpDir, err := os.MkdirTemp("", "TestMkdirAllExtendedLength")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/libgo/go/os/pipe2_illumos.go b/libgo/go/os/pipe2_illumos.go
new file mode 100644
index 0000000..026ce62
--- /dev/null
+++ b/libgo/go/os/pipe2_illumos.go
@@ -0,0 +1,25 @@
+// Copyright 2020 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 illumos
+
+package os
+
+import (
+	"internal/syscall/unix"
+	"syscall"
+)
+
+// Pipe returns a connected pair of Files; reads from r return bytes written to w.
+// It returns the files and an error, if any.
+func Pipe() (r *File, w *File, err error) {
+	var p [2]int
+
+	e := unix.Pipe2(p[0:], syscall.O_CLOEXEC)
+	if e != nil {
+		return nil, nil, NewSyscallError("pipe", e)
+	}
+
+	return newFile(uintptr(p[0]), "|0", kindPipe), newFile(uintptr(p[1]), "|1", kindPipe), nil
+}
diff --git a/libgo/go/os/pipe_bsd.go b/libgo/go/os/pipe_bsd.go
index 0d2d82f..115d6ba 100644
--- a/libgo/go/os/pipe_bsd.go
+++ b/libgo/go/os/pipe_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 aix darwin dragonfly js,wasm solaris
+// +build aix darwin dragonfly js,wasm solaris,!illumos
 
 package os
 
diff --git a/libgo/go/os/pipe_test.go b/libgo/go/os/pipe_test.go
index 429bd81..b98e538 100644
--- a/libgo/go/os/pipe_test.go
+++ b/libgo/go/os/pipe_test.go
@@ -13,7 +13,7 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	osexec "os/exec"
 	"os/signal"
@@ -46,7 +46,7 @@ func TestEPIPE(t *testing.T) {
 		if err == nil {
 			t.Fatal("unexpected success of Write to broken pipe")
 		}
-		if pe, ok := err.(*os.PathError); ok {
+		if pe, ok := err.(*fs.PathError); ok {
 			err = pe.Err
 		}
 		if se, ok := err.(*os.SyscallError); ok {
@@ -160,7 +160,7 @@ func testClosedPipeRace(t *testing.T, read bool) {
 		// Get the amount we have to write to overload a pipe
 		// with no reader.
 		limit = 131073
-		if b, err := ioutil.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
+		if b, err := os.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
 			if i, err := strconv.Atoi(strings.TrimSpace(string(b))); err == nil {
 				limit = i + 1
 			}
@@ -202,10 +202,10 @@ func testClosedPipeRace(t *testing.T, read bool) {
 	}
 	if err == nil {
 		t.Error("I/O on closed pipe unexpectedly succeeded")
-	} else if pe, ok := err.(*os.PathError); !ok {
-		t.Errorf("I/O on closed pipe returned unexpected error type %T; expected os.PathError", pe)
-	} else if pe.Err != os.ErrClosed {
-		t.Errorf("got error %q but expected %q", pe.Err, os.ErrClosed)
+	} else if pe, ok := err.(*fs.PathError); !ok {
+		t.Errorf("I/O on closed pipe returned unexpected error type %T; expected fs.PathError", pe)
+	} else if pe.Err != fs.ErrClosed {
+		t.Errorf("got error %q but expected %q", pe.Err, fs.ErrClosed)
 	} else {
 		t.Logf("I/O returned expected error %q", err)
 	}
@@ -233,7 +233,7 @@ func TestReadNonblockingFd(t *testing.T) {
 		defer syscall.SetNonblock(fd, false)
 		_, err := os.Stdin.Read(make([]byte, 1))
 		if err != nil {
-			if perr, ok := err.(*os.PathError); !ok || perr.Err != syscall.EAGAIN {
+			if perr, ok := err.(*fs.PathError); !ok || perr.Err != syscall.EAGAIN {
 				t.Fatalf("read on nonblocking stdin got %q, should have gotten EAGAIN", err)
 			}
 		}
@@ -308,10 +308,10 @@ func testCloseWithBlockingRead(t *testing.T, r, w *os.File) {
 		if err == nil {
 			t.Error("I/O on closed pipe unexpectedly succeeded")
 		}
-		if pe, ok := err.(*os.PathError); ok {
+		if pe, ok := err.(*fs.PathError); ok {
 			err = pe.Err
 		}
-		if err != io.EOF && err != os.ErrClosed {
+		if err != io.EOF && err != fs.ErrClosed {
 			t.Errorf("got %v, expected EOF or closed", err)
 		}
 	}(c2)
diff --git a/libgo/go/os/proc.go b/libgo/go/os/proc.go
index 7364d63..cbd5a6a 100644
--- a/libgo/go/os/proc.go
+++ b/libgo/go/os/proc.go
@@ -7,6 +7,7 @@
 package os
 
 import (
+	"internal/testlog"
 	"runtime"
 	"syscall"
 )
@@ -60,6 +61,13 @@ func Getgroups() ([]int, error) {
 // For portability, the status code should be in the range [0, 125].
 func Exit(code int) {
 	if code == 0 {
+		if testlog.PanicOnExit0() {
+			// We were told to panic on calls to os.Exit(0).
+			// This is used to fail tests that make an early
+			// unexpected call to os.Exit(0).
+			panic("unexpected call to os.Exit(0) during test")
+		}
+
 		// Give race detector a chance to fail the program.
 		// Racy programs do not have the right to finish successfully.
 		runtime_beforeExit()
diff --git a/libgo/go/os/read_test.go b/libgo/go/os/read_test.go
new file mode 100644
index 0000000..b42ff36
--- /dev/null
+++ b/libgo/go/os/read_test.go
@@ -0,0 +1,131 @@
+// 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 os_test
+
+import (
+	"bytes"
+	. "os"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+func checkNamedSize(t *testing.T, path string, size int64) {
+	dir, err := Stat(path)
+	if err != nil {
+		t.Fatalf("Stat %q (looking for size %d): %s", path, size, err)
+	}
+	if dir.Size() != size {
+		t.Errorf("Stat %q: size %d want %d", path, dir.Size(), size)
+	}
+}
+
+func TestReadFile(t *testing.T) {
+	filename := "rumpelstilzchen"
+	contents, err := ReadFile(filename)
+	if err == nil {
+		t.Fatalf("ReadFile %s: error expected, none found", filename)
+	}
+
+	filename = "read_test.go"
+	contents, err = ReadFile(filename)
+	if err != nil {
+		t.Fatalf("ReadFile %s: %v", filename, err)
+	}
+
+	checkNamedSize(t, filename, int64(len(contents)))
+}
+
+func TestWriteFile(t *testing.T) {
+	f, err := CreateTemp("", "ioutil-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	defer Remove(f.Name())
+
+	msg := "Programming today is a race between software engineers striving to " +
+		"build bigger and better idiot-proof programs, and the Universe trying " +
+		"to produce bigger and better idiots. So far, the Universe is winning."
+
+	if err := WriteFile(f.Name(), []byte(msg), 0644); err != nil {
+		t.Fatalf("WriteFile %s: %v", f.Name(), err)
+	}
+
+	data, err := ReadFile(f.Name())
+	if err != nil {
+		t.Fatalf("ReadFile %s: %v", f.Name(), err)
+	}
+
+	if string(data) != msg {
+		t.Fatalf("ReadFile: wrong data:\nhave %q\nwant %q", string(data), msg)
+	}
+}
+
+func TestReadOnlyWriteFile(t *testing.T) {
+	if Getuid() == 0 {
+		t.Skipf("Root can write to read-only files anyway, so skip the read-only test.")
+	}
+
+	// We don't want to use CreateTemp directly, since that opens a file for us as 0600.
+	tempDir, err := MkdirTemp("", t.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tempDir)
+	filename := filepath.Join(tempDir, "blurp.txt")
+
+	shmorp := []byte("shmorp")
+	florp := []byte("florp")
+	err = WriteFile(filename, shmorp, 0444)
+	if err != nil {
+		t.Fatalf("WriteFile %s: %v", filename, err)
+	}
+	err = WriteFile(filename, florp, 0444)
+	if err == nil {
+		t.Fatalf("Expected an error when writing to read-only file %s", filename)
+	}
+	got, err := ReadFile(filename)
+	if err != nil {
+		t.Fatalf("ReadFile %s: %v", filename, err)
+	}
+	if !bytes.Equal(got, shmorp) {
+		t.Fatalf("want %s, got %s", shmorp, got)
+	}
+}
+
+func TestReadDir(t *testing.T) {
+	dirname := "rumpelstilzchen"
+	_, err := ReadDir(dirname)
+	if err == nil {
+		t.Fatalf("ReadDir %s: error expected, none found", dirname)
+	}
+
+	dirname = "."
+	list, err := ReadDir(dirname)
+	if err != nil {
+		t.Fatalf("ReadDir %s: %v", dirname, err)
+	}
+
+	foundFile := false
+	foundSubDir := false
+	for _, dir := range list {
+		switch {
+		case !dir.IsDir() && dir.Name() == "read_test.go":
+			foundFile = true
+		case dir.IsDir() && dir.Name() == "exec":
+			foundSubDir = true
+		}
+	}
+	if !foundFile {
+		t.Fatalf("ReadDir %s: read_test.go file not found", dirname)
+	}
+	if !foundSubDir {
+		// This doesn't work in the gofrontend testsuite framework.
+		if runtime.Compiler == "gc" {
+			t.Fatalf("ReadDir %s: exec directory not found", dirname)
+		}
+	}
+}
diff --git a/libgo/go/os/readfrom_linux_test.go b/libgo/go/os/readfrom_linux_test.go
index 00faf39..3704717 100644
--- a/libgo/go/os/readfrom_linux_test.go
+++ b/libgo/go/os/readfrom_linux_test.go
@@ -8,8 +8,8 @@ import (
 	"bytes"
 	"internal/poll"
 	"io"
-	"io/ioutil"
 	"math/rand"
+	"os"
 	. "os"
 	"path/filepath"
 	"strconv"
@@ -173,7 +173,7 @@ func TestCopyFileRange(t *testing.T) {
 	})
 	t.Run("Nil", func(t *testing.T) {
 		var nilFile *File
-		anyFile, err := ioutil.TempFile("", "")
+		anyFile, err := os.CreateTemp("", "")
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/libgo/go/os/removeall_at.go b/libgo/go/os/removeall_at.go
index 8bbdcf0..f9eafa1 100644
--- a/libgo/go/os/removeall_at.go
+++ b/libgo/go/os/removeall_at.go
@@ -22,7 +22,7 @@ func removeAll(path string) error {
 	// The rmdir system call does not permit removing ".",
 	// so we don't permit it either.
 	if endsWithDot(path) {
-		return &PathError{"RemoveAll", path, syscall.EINVAL}
+		return &PathError{Op: "RemoveAll", Path: path, Err: syscall.EINVAL}
 	}
 
 	// Simple case: if Remove works, we're done.
@@ -70,7 +70,7 @@ func removeAllFrom(parent *File, base string) error {
 	// whose contents need to be removed.
 	// Otherwise just return the error.
 	if err != syscall.EISDIR && err != syscall.EPERM && err != syscall.EACCES {
-		return &PathError{"unlinkat", base, err}
+		return &PathError{Op: "unlinkat", Path: base, Err: err}
 	}
 
 	// Is this a directory we need to recurse into?
@@ -80,11 +80,11 @@ func removeAllFrom(parent *File, base string) error {
 		if IsNotExist(statErr) {
 			return nil
 		}
-		return &PathError{"fstatat", base, statErr}
+		return &PathError{Op: "fstatat", Path: base, Err: statErr}
 	}
 	if statInfo.Mode&syscall.S_IFMT != syscall.S_IFDIR {
 		// Not a directory; return the error from the unix.Unlinkat.
-		return &PathError{"unlinkat", base, err}
+		return &PathError{Op: "unlinkat", Path: base, Err: err}
 	}
 
 	// Remove the directory's entries.
@@ -99,7 +99,7 @@ func removeAllFrom(parent *File, base string) error {
 			if IsNotExist(err) {
 				return nil
 			}
-			recurseErr = &PathError{"openfdat", base, err}
+			recurseErr = &PathError{Op: "openfdat", Path: base, Err: err}
 			break
 		}
 
@@ -113,7 +113,7 @@ func removeAllFrom(parent *File, base string) error {
 				if IsNotExist(readErr) {
 					return nil
 				}
-				return &PathError{"readdirnames", base, readErr}
+				return &PathError{Op: "readdirnames", Path: base, Err: readErr}
 			}
 
 			respSize = len(names)
@@ -159,7 +159,7 @@ func removeAllFrom(parent *File, base string) error {
 	if recurseErr != nil {
 		return recurseErr
 	}
-	return &PathError{"unlinkat", base, unlinkError}
+	return &PathError{Op: "unlinkat", Path: base, Err: unlinkError}
 }
 
 // openFdAt opens path relative to the directory in fd.
diff --git a/libgo/go/os/removeall_noat.go b/libgo/go/os/removeall_noat.go
index fb9b45f..a4cde5a 100644
--- a/libgo/go/os/removeall_noat.go
+++ b/libgo/go/os/removeall_noat.go
@@ -23,7 +23,7 @@ func removeAll(path string) error {
 	// so we don't permit it to remain consistent with the
 	// "at" implementation of RemoveAll.
 	if endsWithDot(path) {
-		return &PathError{"RemoveAll", path, syscall.EINVAL}
+		return &PathError{Op: "RemoveAll", Path: path, Err: syscall.EINVAL}
 	}
 
 	// Simple case: if Remove works, we're done.
diff --git a/libgo/go/os/removeall_test.go b/libgo/go/os/removeall_test.go
index 8a71f68..3a2f6e3 100644
--- a/libgo/go/os/removeall_test.go
+++ b/libgo/go/os/removeall_test.go
@@ -6,7 +6,7 @@ package os_test
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -15,7 +15,7 @@ import (
 )
 
 func TestRemoveAll(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -128,7 +128,7 @@ func TestRemoveAllLarge(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -158,7 +158,7 @@ func TestRemoveAllLarge(t *testing.T) {
 
 func TestRemoveAllLongPath(t *testing.T) {
 	switch runtime.GOOS {
-	case "aix", "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "illumos", "solaris":
+	case "aix", "darwin", "ios", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "illumos", "solaris":
 		break
 	default:
 		t.Skip("skipping for not implemented platforms")
@@ -169,7 +169,7 @@ func TestRemoveAllLongPath(t *testing.T) {
 		t.Fatalf("Could not get wd: %s", err)
 	}
 
-	startPath, err := ioutil.TempDir("", "TestRemoveAllLongPath-")
+	startPath, err := os.MkdirTemp("", "TestRemoveAllLongPath-")
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
@@ -211,7 +211,7 @@ func TestRemoveAllDot(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Could not get wd: %s", err)
 	}
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllDot-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllDot-")
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
@@ -236,7 +236,7 @@ func TestRemoveAllDot(t *testing.T) {
 func TestRemoveAllDotDot(t *testing.T) {
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllDotDot-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllDotDot-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -261,7 +261,7 @@ func TestRemoveAllDotDot(t *testing.T) {
 func TestRemoveReadOnlyDir(t *testing.T) {
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveReadOnlyDir-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveReadOnlyDir-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -298,7 +298,7 @@ func TestRemoveAllButReadOnlyAndPathError(t *testing.T) {
 
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllButReadOnly-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllButReadOnly-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -355,11 +355,12 @@ func TestRemoveAllButReadOnlyAndPathError(t *testing.T) {
 	// The error should be of type *PathError.
 	// see issue 30491 for details.
 	if pathErr, ok := err.(*PathError); ok {
-		if g, w := pathErr.Path, filepath.Join(tempDir, "b", "y"); g != w {
-			t.Errorf("got %q, expected pathErr.path %q", g, w)
+		want := filepath.Join(tempDir, "b", "y")
+		if pathErr.Path != want {
+			t.Errorf("RemoveAll(%q): err.Path=%q, want %q", tempDir, pathErr.Path, want)
 		}
 	} else {
-		t.Errorf("got %T, expected *os.PathError", err)
+		t.Errorf("RemoveAll(%q): error has type %T, want *fs.PathError", tempDir, err)
 	}
 
 	for _, dir := range dirs {
@@ -388,7 +389,7 @@ func TestRemoveUnreadableDir(t *testing.T) {
 
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllButReadOnly-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllButReadOnly-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -412,7 +413,7 @@ func TestRemoveAllWithMoreErrorThanReqSize(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/libgo/go/os/signal/example_unix_test.go b/libgo/go/os/signal/example_unix_test.go
new file mode 100644
index 0000000..a0af37a
--- /dev/null
+++ b/libgo/go/os/signal/example_unix_test.go
@@ -0,0 +1,47 @@
+// Copyright 2020 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 signal_test
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"time"
+)
+
+// This example passes a context with a signal to tell a blocking function that
+// it should abandon its work after a signal is received.
+func ExampleNotifyContext() {
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	p, err := os.FindProcess(os.Getpid())
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// On a Unix-like system, pressing Ctrl+C on a keyboard sends a
+	// SIGINT signal to the process of the program in execution.
+	//
+	// This example simulates that by sending a SIGINT signal to itself.
+	if err := p.Signal(os.Interrupt); err != nil {
+		log.Fatal(err)
+	}
+
+	select {
+	case <-time.After(time.Second):
+		fmt.Println("missed signal")
+	case <-ctx.Done():
+		fmt.Println(ctx.Err()) // prints "context canceled"
+		stop()                 // stop receiving signal notifications as soon as possible.
+	}
+
+	// Output:
+	// context canceled
+}
diff --git a/libgo/go/os/signal/signal.go b/libgo/go/os/signal/signal.go
index 8e31aa2..4250a7e 100644
--- a/libgo/go/os/signal/signal.go
+++ b/libgo/go/os/signal/signal.go
@@ -5,6 +5,7 @@
 package signal
 
 import (
+	"context"
 	"os"
 	"sync"
 )
@@ -257,3 +258,77 @@ func process(sig os.Signal) {
 		}
 	}
 }
+
+// NotifyContext returns a copy of the parent context that is marked done
+// (its Done channel is closed) when one of the listed signals arrives,
+// when the returned stop function is called, or when the parent context's
+// Done channel is closed, whichever happens first.
+//
+// The stop function unregisters the signal behavior, which, like signal.Reset,
+// may restore the default behavior for a given signal. For example, the default
+// behavior of a Go program receiving os.Interrupt is to exit. Calling
+// NotifyContext(parent, os.Interrupt) will change the behavior to cancel
+// the returned context. Future interrupts received will not trigger the default
+// (exit) behavior until the returned stop function is called.
+//
+// The stop function releases resources associated with it, so code should
+// call stop as soon as the operations running in this Context complete and
+// signals no longer need to be diverted to the context.
+func NotifyContext(parent context.Context, signals ...os.Signal) (ctx context.Context, stop context.CancelFunc) {
+	ctx, cancel := context.WithCancel(parent)
+	c := &signalCtx{
+		Context: ctx,
+		cancel:  cancel,
+		signals: signals,
+	}
+	c.ch = make(chan os.Signal, 1)
+	Notify(c.ch, c.signals...)
+	if ctx.Err() == nil {
+		go func() {
+			select {
+			case <-c.ch:
+				c.cancel()
+			case <-c.Done():
+			}
+		}()
+	}
+	return c, c.stop
+}
+
+type signalCtx struct {
+	context.Context
+
+	cancel  context.CancelFunc
+	signals []os.Signal
+	ch      chan os.Signal
+}
+
+func (c *signalCtx) stop() {
+	c.cancel()
+	Stop(c.ch)
+}
+
+type stringer interface {
+	String() string
+}
+
+func (c *signalCtx) String() string {
+	var buf []byte
+	// We know that the type of c.Context is context.cancelCtx, and we know that the
+	// String method of cancelCtx returns a string that ends with ".WithCancel".
+	name := c.Context.(stringer).String()
+	name = name[:len(name)-len(".WithCancel")]
+	buf = append(buf, "signal.NotifyContext("+name...)
+	if len(c.signals) != 0 {
+		buf = append(buf, ", ["...)
+		for i, s := range c.signals {
+			buf = append(buf, s.String()...)
+			if i != len(c.signals)-1 {
+				buf = append(buf, ' ')
+			}
+		}
+		buf = append(buf, ']')
+	}
+	buf = append(buf, ')')
+	return string(buf)
+}
diff --git a/libgo/go/os/signal/signal_cgo_test.go b/libgo/go/os/signal/signal_cgo_test.go
index a117221..a8a4856 100644
--- a/libgo/go/os/signal/signal_cgo_test.go
+++ b/libgo/go/os/signal/signal_cgo_test.go
@@ -17,6 +17,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"os/exec"
 	ptypkg "os/signal/internal/pty"
@@ -127,7 +128,7 @@ func TestTerminalSignal(t *testing.T) {
 				if len(line) > 0 || len(handled) > 0 {
 					t.Logf("%q", append(handled, line...))
 				}
-				if perr, ok := err.(*os.PathError); ok {
+				if perr, ok := err.(*fs.PathError); ok {
 					err = perr.Err
 				}
 				// EOF means pty is closed.
diff --git a/libgo/go/os/signal/signal_test.go b/libgo/go/os/signal/signal_test.go
index 98a1cc1..66b8327 100644
--- a/libgo/go/os/signal/signal_test.go
+++ b/libgo/go/os/signal/signal_test.go
@@ -8,10 +8,10 @@ package signal
 
 import (
 	"bytes"
+	"context"
 	"flag"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"runtime"
@@ -303,7 +303,7 @@ func TestDetectNohup(t *testing.T) {
 		os.Remove("nohup.out")
 		out, err := exec.Command("/usr/bin/nohup", os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput()
 
-		data, _ := ioutil.ReadFile("nohup.out")
+		data, _ := os.ReadFile("nohup.out")
 		os.Remove("nohup.out")
 		if err != nil {
 			t.Errorf("ran test with -check_sighup_ignored under nohup and it failed: expected success.\nError: %v\nOutput:\n%s%s", err, out, data)
@@ -674,3 +674,164 @@ func TestTime(t *testing.T) {
 	close(stop)
 	<-done
 }
+
+func TestNotifyContext(t *testing.T) {
+	c, stop := NotifyContext(context.Background(), syscall.SIGINT)
+	defer stop()
+
+	if want, got := "signal.NotifyContext(context.Background, [interrupt])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+
+	syscall.Kill(syscall.Getpid(), syscall.SIGINT)
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("timed out waiting for context to be done after SIGINT")
+	}
+}
+
+func TestNotifyContextStop(t *testing.T) {
+	Ignore(syscall.SIGHUP)
+	if !Ignored(syscall.SIGHUP) {
+		t.Errorf("expected SIGHUP to be ignored when explicitly ignoring it.")
+	}
+
+	parent, cancelParent := context.WithCancel(context.Background())
+	defer cancelParent()
+	c, stop := NotifyContext(parent, syscall.SIGHUP)
+	defer stop()
+
+	// If we're being notified, then the signal should not be ignored.
+	if Ignored(syscall.SIGHUP) {
+		t.Errorf("expected SIGHUP to not be ignored.")
+	}
+
+	if want, got := "signal.NotifyContext(context.Background.WithCancel, [hangup])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, wanted %q", got, want)
+	}
+
+	stop()
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("timed out waiting for context to be done after calling stop")
+	}
+}
+
+func TestNotifyContextCancelParent(t *testing.T) {
+	parent, cancelParent := context.WithCancel(context.Background())
+	defer cancelParent()
+	c, stop := NotifyContext(parent, syscall.SIGINT)
+	defer stop()
+
+	if want, got := "signal.NotifyContext(context.Background.WithCancel, [interrupt])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+
+	cancelParent()
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("timed out waiting for parent context to be canceled")
+	}
+}
+
+func TestNotifyContextPrematureCancelParent(t *testing.T) {
+	parent, cancelParent := context.WithCancel(context.Background())
+	defer cancelParent()
+
+	cancelParent() // Prematurely cancel context before calling NotifyContext.
+	c, stop := NotifyContext(parent, syscall.SIGINT)
+	defer stop()
+
+	if want, got := "signal.NotifyContext(context.Background.WithCancel, [interrupt])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("timed out waiting for parent context to be canceled")
+	}
+}
+
+func TestNotifyContextSimultaneousNotifications(t *testing.T) {
+	c, stop := NotifyContext(context.Background(), syscall.SIGINT)
+	defer stop()
+
+	if want, got := "signal.NotifyContext(context.Background, [interrupt])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+
+	var wg sync.WaitGroup
+	n := 10
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			syscall.Kill(syscall.Getpid(), syscall.SIGINT)
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("expected context to be canceled")
+	}
+}
+
+func TestNotifyContextSimultaneousStop(t *testing.T) {
+	c, stop := NotifyContext(context.Background(), syscall.SIGINT)
+	defer stop()
+
+	if want, got := "signal.NotifyContext(context.Background, [interrupt])", fmt.Sprint(c); want != got {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+
+	var wg sync.WaitGroup
+	n := 10
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			stop()
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+	select {
+	case <-c.Done():
+		if got := c.Err(); got != context.Canceled {
+			t.Errorf("c.Err() = %q, want %q", got, context.Canceled)
+		}
+	case <-time.After(time.Second):
+		t.Errorf("expected context to be canceled")
+	}
+}
+
+func TestNotifyContextStringer(t *testing.T) {
+	parent, cancelParent := context.WithCancel(context.Background())
+	defer cancelParent()
+	c, stop := NotifyContext(parent, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	want := `signal.NotifyContext(context.Background.WithCancel, [hangup interrupt terminated])`
+	if got := fmt.Sprint(c); got != want {
+		t.Errorf("c.String() = %q, want %q", got, want)
+	}
+}
diff --git a/libgo/go/os/stat_plan9.go b/libgo/go/os/stat_plan9.go
index b43339a..57ae6fb 100644
--- a/libgo/go/os/stat_plan9.go
+++ b/libgo/go/os/stat_plan9.go
@@ -11,7 +11,7 @@ import (
 
 const bitSize16 = 2
 
-func fileInfoFromStat(d *syscall.Dir) FileInfo {
+func fileInfoFromStat(d *syscall.Dir) *fileStat {
 	fs := &fileStat{
 		name:    d.Name,
 		size:    d.Length,
@@ -65,7 +65,7 @@ func dirstat(arg interface{}) (*syscall.Dir, error) {
 		}
 
 		if n < bitSize16 {
-			return nil, &PathError{"stat", name, err}
+			return nil, &PathError{Op: "stat", Path: name, Err: err}
 		}
 
 		// Pull the real size out of the stat message.
@@ -76,7 +76,7 @@ func dirstat(arg interface{}) (*syscall.Dir, error) {
 		if size <= n {
 			d, err := syscall.UnmarshalDir(buf[:n])
 			if err != nil {
-				return nil, &PathError{"stat", name, err}
+				return nil, &PathError{Op: "stat", Path: name, Err: err}
 			}
 			return d, nil
 		}
@@ -87,7 +87,7 @@ func dirstat(arg interface{}) (*syscall.Dir, error) {
 		err = syscall.ErrBadStat
 	}
 
-	return nil, &PathError{"stat", name, err}
+	return nil, &PathError{Op: "stat", Path: name, Err: err}
 }
 
 // statNolog implements Stat for Plan 9.
diff --git a/libgo/go/os/stat_test.go b/libgo/go/os/stat_test.go
index 60f3b4c..c409f0f 100644
--- a/libgo/go/os/stat_test.go
+++ b/libgo/go/os/stat_test.go
@@ -6,7 +6,7 @@ package os_test
 
 import (
 	"internal/testenv"
-	"io/ioutil"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -14,7 +14,7 @@ import (
 )
 
 // 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)) {
+func testStatAndLstat(t *testing.T, path string, isLink bool, statCheck, lstatCheck func(*testing.T, string, fs.FileInfo)) {
 	// test os.Stat
 	sfi, err := os.Stat(path)
 	if err != nil {
@@ -70,7 +70,7 @@ func testStatAndLstat(t *testing.T, path string, isLink bool, statCheck, lstatCh
 		}
 	}
 
-	// test os.FileInfo returned by os.Readdir
+	// test fs.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
@@ -88,7 +88,7 @@ func testStatAndLstat(t *testing.T, path string, isLink bool, statCheck, lstatCh
 		t.Error(err)
 		return
 	}
-	var lsfi2 os.FileInfo
+	var lsfi2 fs.FileInfo
 	base := filepath.Base(path)
 	for _, fi2 := range fis {
 		if fi2.Name() == base {
@@ -108,34 +108,34 @@ func testStatAndLstat(t *testing.T, path string, isLink bool, statCheck, lstatCh
 }
 
 // testIsDir verifies that fi refers to directory.
-func testIsDir(t *testing.T, path string, fi os.FileInfo) {
+func testIsDir(t *testing.T, path string, fi fs.FileInfo) {
 	t.Helper()
 	if !fi.IsDir() {
 		t.Errorf("%q should be a directory", path)
 	}
-	if fi.Mode()&os.ModeSymlink != 0 {
+	if fi.Mode()&fs.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) {
+func testIsSymlink(t *testing.T, path string, fi fs.FileInfo) {
 	t.Helper()
 	if fi.IsDir() {
 		t.Errorf("%q should not be a directory", path)
 	}
-	if fi.Mode()&os.ModeSymlink == 0 {
+	if fi.Mode()&fs.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) {
+func testIsFile(t *testing.T, path string, fi fs.FileInfo) {
 	t.Helper()
 	if fi.IsDir() {
 		t.Errorf("%q should not be a directory", path)
 	}
-	if fi.Mode()&os.ModeSymlink != 0 {
+	if fi.Mode()&fs.ModeSymlink != 0 {
 		t.Errorf("%q should not be a symlink", path)
 	}
 }
@@ -185,7 +185,7 @@ func testSymlinkSameFile(t *testing.T, path, link string) {
 func TestDirAndSymlinkStats(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestDirAndSymlinkStats")
+	tmpdir, err := os.MkdirTemp("", "TestDirAndSymlinkStats")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -218,14 +218,14 @@ func TestDirAndSymlinkStats(t *testing.T) {
 func TestFileAndSymlinkStats(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestFileAndSymlinkStats")
+	tmpdir, err := os.MkdirTemp("", "TestFileAndSymlinkStats")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	file := filepath.Join(tmpdir, "file")
-	err = ioutil.WriteFile(file, []byte(""), 0644)
+	err = os.WriteFile(file, []byte(""), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -252,7 +252,7 @@ func TestFileAndSymlinkStats(t *testing.T) {
 func TestSymlinkWithTrailingSlash(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestSymlinkWithTrailingSlash")
+	tmpdir, err := os.MkdirTemp("", "TestSymlinkWithTrailingSlash")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/libgo/go/os/stat_unix.go b/libgo/go/os/stat_unix.go
index d489ad1..7873bf9 100644
--- a/libgo/go/os/stat_unix.go
+++ b/libgo/go/os/stat_unix.go
@@ -19,7 +19,7 @@ func (f *File) Stat() (FileInfo, error) {
 	var fs fileStat
 	err := f.pfd.Fstat(&fs.sys)
 	if err != nil {
-		return nil, &PathError{"stat", f.name, err}
+		return nil, &PathError{Op: "stat", Path: f.name, Err: err}
 	}
 	fillFileStatFromSys(&fs, f.name)
 	return &fs, nil
@@ -28,9 +28,11 @@ func (f *File) Stat() (FileInfo, error) {
 // statNolog stats a file with no test logging.
 func statNolog(name string) (FileInfo, error) {
 	var fs fileStat
-	err := syscall.Stat(name, &fs.sys)
+	err := ignoringEINTR(func() error {
+		return syscall.Stat(name, &fs.sys)
+	})
 	if err != nil {
-		return nil, &PathError{"stat", name, err}
+		return nil, &PathError{Op: "stat", Path: name, Err: err}
 	}
 	fillFileStatFromSys(&fs, name)
 	return &fs, nil
@@ -39,9 +41,11 @@ func statNolog(name string) (FileInfo, error) {
 // lstatNolog lstats a file with no test logging.
 func lstatNolog(name string) (FileInfo, error) {
 	var fs fileStat
-	err := syscall.Lstat(name, &fs.sys)
+	err := ignoringEINTR(func() error {
+		return syscall.Lstat(name, &fs.sys)
+	})
 	if err != nil {
-		return nil, &PathError{"lstat", name, err}
+		return nil, &PathError{Op: "lstat", Path: name, Err: err}
 	}
 	fillFileStatFromSys(&fs, name)
 	return &fs, nil
diff --git a/libgo/go/os/tempfile.go b/libgo/go/os/tempfile.go
new file mode 100644
index 0000000..2728485
--- /dev/null
+++ b/libgo/go/os/tempfile.go
@@ -0,0 +1,118 @@
+// Copyright 2010 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 (
+	"errors"
+	"strings"
+)
+
+// fastrand provided by runtime.
+// We generate random temporary file names so that there's a good
+// chance the file doesn't exist yet - keeps the number of tries in
+// TempFile to a minimum.
+func fastrand() uint32
+
+func nextRandom() string {
+	return uitoa(uint(fastrand()))
+}
+
+// CreateTemp creates a new temporary file in the directory dir,
+// opens the file for reading and writing, and returns the resulting file.
+// The filename is generated by taking pattern and adding a random string to the end.
+// If pattern includes a "*", the random string replaces the last "*".
+// If dir is the empty string, TempFile uses the default directory for temporary files, as returned by TempDir.
+// Multiple programs or goroutines calling CreateTemp simultaneously will not choose the same file.
+// The caller can use the file's Name method to find the pathname of the file.
+// It is the caller's responsibility to remove the file when it is no longer needed.
+func CreateTemp(dir, pattern string) (*File, error) {
+	if dir == "" {
+		dir = TempDir()
+	}
+
+	prefix, suffix, err := prefixAndSuffix(pattern)
+	if err != nil {
+		return nil, &PathError{Op: "createtemp", Path: pattern, Err: err}
+	}
+	prefix = joinPath(dir, prefix)
+
+	try := 0
+	for {
+		name := prefix + nextRandom() + suffix
+		f, err := OpenFile(name, O_RDWR|O_CREATE|O_EXCL, 0600)
+		if IsExist(err) {
+			if try++; try < 10000 {
+				continue
+			}
+			return nil, &PathError{Op: "createtemp", Path: dir + string(PathSeparator) + prefix + "*" + suffix, Err: ErrExist}
+		}
+		return f, err
+	}
+}
+
+var errPatternHasSeparator = errors.New("pattern contains path separator")
+
+// prefixAndSuffix splits pattern by the last wildcard "*", if applicable,
+// returning prefix as the part before "*" and suffix as the part after "*".
+func prefixAndSuffix(pattern string) (prefix, suffix string, err error) {
+	for i := 0; i < len(pattern); i++ {
+		if IsPathSeparator(pattern[i]) {
+			return "", "", errPatternHasSeparator
+		}
+	}
+	if pos := strings.LastIndex(pattern, "*"); pos != -1 {
+		prefix, suffix = pattern[:pos], pattern[pos+1:]
+	} else {
+		prefix = pattern
+	}
+	return prefix, suffix, nil
+}
+
+// MkdirTemp creates a new temporary directory in the directory dir
+// and returns the pathname of the new directory.
+// The new directory's name is generated by adding a random string to the end of pattern.
+// If pattern includes a "*", the random string replaces the last "*" instead.
+// If dir is the empty string, TempFile uses the default directory for temporary files, as returned by TempDir.
+// Multiple programs or goroutines calling MkdirTemp simultaneously will not choose the same directory.
+// It is the caller's responsibility to remove the directory when it is no longer needed.
+func MkdirTemp(dir, pattern string) (string, error) {
+	if dir == "" {
+		dir = TempDir()
+	}
+
+	prefix, suffix, err := prefixAndSuffix(pattern)
+	if err != nil {
+		return "", &PathError{Op: "mkdirtemp", Path: pattern, Err: err}
+	}
+	prefix = joinPath(dir, prefix)
+
+	try := 0
+	for {
+		name := prefix + nextRandom() + suffix
+		err := Mkdir(name, 0700)
+		if err == nil {
+			return name, nil
+		}
+		if IsExist(err) {
+			if try++; try < 10000 {
+				continue
+			}
+			return "", &PathError{Op: "mkdirtemp", Path: dir + string(PathSeparator) + prefix + "*" + suffix, Err: ErrExist}
+		}
+		if IsNotExist(err) {
+			if _, err := Stat(dir); IsNotExist(err) {
+				return "", err
+			}
+		}
+		return "", err
+	}
+}
+
+func joinPath(dir, name string) string {
+	if len(dir) > 0 && IsPathSeparator(dir[len(dir)-1]) {
+		return dir + name
+	}
+	return dir + string(PathSeparator) + name
+}
diff --git a/libgo/go/os/tempfile_test.go b/libgo/go/os/tempfile_test.go
new file mode 100644
index 0000000..e71a244
--- /dev/null
+++ b/libgo/go/os/tempfile_test.go
@@ -0,0 +1,193 @@
+// Copyright 2010 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 (
+	"errors"
+	"io/fs"
+	. "os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+func TestCreateTemp(t *testing.T) {
+	dir, err := MkdirTemp("", "TestCreateTempBadDir")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(dir)
+
+	nonexistentDir := filepath.Join(dir, "_not_exists_")
+	f, err := CreateTemp(nonexistentDir, "foo")
+	if f != nil || err == nil {
+		t.Errorf("CreateTemp(%q, `foo`) = %v, %v", nonexistentDir, f, err)
+	}
+}
+
+func TestCreateTempPattern(t *testing.T) {
+	tests := []struct{ pattern, prefix, suffix string }{
+		{"tempfile_test", "tempfile_test", ""},
+		{"tempfile_test*", "tempfile_test", ""},
+		{"tempfile_test*xyz", "tempfile_test", "xyz"},
+	}
+	for _, test := range tests {
+		f, err := CreateTemp("", test.pattern)
+		if err != nil {
+			t.Errorf("CreateTemp(..., %q) error: %v", test.pattern, err)
+			continue
+		}
+		defer Remove(f.Name())
+		base := filepath.Base(f.Name())
+		f.Close()
+		if !(strings.HasPrefix(base, test.prefix) && strings.HasSuffix(base, test.suffix)) {
+			t.Errorf("CreateTemp pattern %q created bad name %q; want prefix %q & suffix %q",
+				test.pattern, base, test.prefix, test.suffix)
+		}
+	}
+}
+
+func TestCreateTempBadPattern(t *testing.T) {
+	tmpDir, err := MkdirTemp("", t.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	const sep = string(PathSeparator)
+	tests := []struct {
+		pattern string
+		wantErr bool
+	}{
+		{"ioutil*test", false},
+		{"tempfile_test*foo", false},
+		{"tempfile_test" + sep + "foo", true},
+		{"tempfile_test*" + sep + "foo", true},
+		{"tempfile_test" + sep + "*foo", true},
+		{sep + "tempfile_test" + sep + "*foo", true},
+		{"tempfile_test*foo" + sep, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.pattern, func(t *testing.T) {
+			tmpfile, err := CreateTemp(tmpDir, tt.pattern)
+			if tmpfile != nil {
+				defer tmpfile.Close()
+			}
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("CreateTemp(..., %#q) succeeded, expected error", tt.pattern)
+				}
+				if !errors.Is(err, ErrPatternHasSeparator) {
+					t.Errorf("CreateTemp(..., %#q): %v, expected ErrPatternHasSeparator", tt.pattern, err)
+				}
+			} else if err != nil {
+				t.Errorf("CreateTemp(..., %#q): %v", tt.pattern, err)
+			}
+		})
+	}
+}
+
+func TestMkdirTemp(t *testing.T) {
+	name, err := MkdirTemp("/_not_exists_", "foo")
+	if name != "" || err == nil {
+		t.Errorf("MkdirTemp(`/_not_exists_`, `foo`) = %v, %v", name, err)
+	}
+
+	tests := []struct {
+		pattern                string
+		wantPrefix, wantSuffix string
+	}{
+		{"tempfile_test", "tempfile_test", ""},
+		{"tempfile_test*", "tempfile_test", ""},
+		{"tempfile_test*xyz", "tempfile_test", "xyz"},
+	}
+
+	dir := filepath.Clean(TempDir())
+
+	runTestMkdirTemp := func(t *testing.T, pattern, wantRePat string) {
+		name, err := MkdirTemp(dir, pattern)
+		if name == "" || err != nil {
+			t.Fatalf("MkdirTemp(dir, `tempfile_test`) = %v, %v", name, err)
+		}
+		defer Remove(name)
+
+		re := regexp.MustCompile(wantRePat)
+		if !re.MatchString(name) {
+			t.Errorf("MkdirTemp(%q, %q) created bad name\n\t%q\ndid not match pattern\n\t%q", dir, pattern, name, wantRePat)
+		}
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.pattern, func(t *testing.T) {
+			wantRePat := "^" + regexp.QuoteMeta(filepath.Join(dir, tt.wantPrefix)) + "[0-9]+" + regexp.QuoteMeta(tt.wantSuffix) + "$"
+			runTestMkdirTemp(t, tt.pattern, wantRePat)
+		})
+	}
+
+	// Separately testing "*xyz" (which has no prefix). That is when constructing the
+	// pattern to assert on, as in the previous loop, using filepath.Join for an empty
+	// prefix filepath.Join(dir, ""), produces the pattern:
+	//     ^<DIR>[0-9]+xyz$
+	// yet we just want to match
+	//     "^<DIR>/[0-9]+xyz"
+	t.Run("*xyz", func(t *testing.T) {
+		wantRePat := "^" + regexp.QuoteMeta(filepath.Join(dir)) + regexp.QuoteMeta(string(filepath.Separator)) + "[0-9]+xyz$"
+		runTestMkdirTemp(t, "*xyz", wantRePat)
+	})
+}
+
+// test that we return a nice error message if the dir argument to TempDir doesn't
+// exist (or that it's empty and TempDir doesn't exist)
+func TestMkdirTempBadDir(t *testing.T) {
+	dir, err := MkdirTemp("", "MkdirTempBadDir")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(dir)
+
+	badDir := filepath.Join(dir, "not-exist")
+	_, err = MkdirTemp(badDir, "foo")
+	if pe, ok := err.(*fs.PathError); !ok || !IsNotExist(err) || pe.Path != badDir {
+		t.Errorf("TempDir error = %#v; want PathError for path %q satisifying IsNotExist", err, badDir)
+	}
+}
+
+func TestMkdirTempBadPattern(t *testing.T) {
+	tmpDir, err := MkdirTemp("", t.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer RemoveAll(tmpDir)
+
+	const sep = string(PathSeparator)
+	tests := []struct {
+		pattern string
+		wantErr bool
+	}{
+		{"ioutil*test", false},
+		{"tempfile_test*foo", false},
+		{"tempfile_test" + sep + "foo", true},
+		{"tempfile_test*" + sep + "foo", true},
+		{"tempfile_test" + sep + "*foo", true},
+		{sep + "tempfile_test" + sep + "*foo", true},
+		{"tempfile_test*foo" + sep, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.pattern, func(t *testing.T) {
+			_, err := MkdirTemp(tmpDir, tt.pattern)
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("MkdirTemp(..., %#q) succeeded, expected error", tt.pattern)
+				}
+				if !errors.Is(err, ErrPatternHasSeparator) {
+					t.Errorf("MkdirTemp(..., %#q): %v, expected ErrPatternHasSeparator", tt.pattern, err)
+				}
+			} else if err != nil {
+				t.Errorf("MkdirTemp(..., %#q): %v", tt.pattern, err)
+			}
+		})
+	}
+}
diff --git a/libgo/go/os/testdata/hello b/libgo/go/os/testdata/hello
new file mode 100644
index 0000000..e47c092
--- /dev/null
+++ b/libgo/go/os/testdata/hello
@@ -0,0 +1 @@
+Hello, Gophers!
diff --git a/libgo/go/os/timeout_test.go b/libgo/go/os/timeout_test.go
index 99b94c2..0a39f46 100644
--- a/libgo/go/os/timeout_test.go
+++ b/libgo/go/os/timeout_test.go
@@ -11,7 +11,6 @@ package os_test
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"os/signal"
@@ -29,7 +28,7 @@ func TestNonpollableDeadline(t *testing.T) {
 		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
-	f, err := ioutil.TempFile("", "ostest")
+	f, err := os.CreateTemp("", "ostest")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -429,7 +428,7 @@ func testVariousDeadlines(t *testing.T) {
 					if err := r.SetDeadline(t0.Add(timeout)); err != nil {
 						t.Error(err)
 					}
-					n, err := io.Copy(ioutil.Discard, r)
+					n, err := io.Copy(io.Discard, r)
 					dt := time.Since(t0)
 					r.Close()
 					actvch <- result{n, err, dt}
@@ -565,7 +564,7 @@ func TestRacyWrite(t *testing.T) {
 	var wg sync.WaitGroup
 	defer wg.Wait()
 
-	go io.Copy(ioutil.Discard, r)
+	go io.Copy(io.Discard, r)
 
 	w.SetWriteDeadline(time.Now().Add(time.Millisecond))
 	for i := 0; i < 10; i++ {
diff --git a/libgo/go/os/types.go b/libgo/go/os/types.go
index 4b6c084..d8edd98 100644
--- a/libgo/go/os/types.go
+++ b/libgo/go/os/types.go
@@ -5,8 +5,8 @@
 package os
 
 import (
+	"io/fs"
 	"syscall"
-	"time"
 )
 
 // Getpagesize returns the underlying system's memory page size.
@@ -18,21 +18,14 @@ type File struct {
 }
 
 // A FileInfo describes a file and is returned by Stat and Lstat.
-type FileInfo interface {
-	Name() string       // base name of the file
-	Size() int64        // length in bytes for regular files; system-dependent for others
-	Mode() FileMode     // file mode bits
-	ModTime() time.Time // modification time
-	IsDir() bool        // abbreviation for Mode().IsDir()
-	Sys() interface{}   // underlying data source (can return nil)
-}
+type FileInfo = fs.FileInfo
 
 // A FileMode represents a file's mode and permission bits.
 // The bits have the same definition on all systems, so that
 // information about files can be moved from one system
 // to another portably. Not all bits apply to all systems.
 // The only required bit is ModeDir for directories.
-type FileMode uint32
+type FileMode = fs.FileMode
 
 // The defined file mode bits are the most significant bits of the FileMode.
 // The nine least-significant bits are the standard Unix rwxrwxrwx permissions.
@@ -42,69 +35,26 @@ type FileMode uint32
 const (
 	// The single letters are the abbreviations
 	// used by the String method's formatting.
-	ModeDir        FileMode = 1 << (32 - 1 - iota) // d: is a directory
-	ModeAppend                                     // a: append-only
-	ModeExclusive                                  // l: exclusive use
-	ModeTemporary                                  // T: temporary file; Plan 9 only
-	ModeSymlink                                    // L: symbolic link
-	ModeDevice                                     // D: device file
-	ModeNamedPipe                                  // p: named pipe (FIFO)
-	ModeSocket                                     // S: Unix domain socket
-	ModeSetuid                                     // u: setuid
-	ModeSetgid                                     // g: setgid
-	ModeCharDevice                                 // c: Unix character device, when ModeDevice is set
-	ModeSticky                                     // t: sticky
-	ModeIrregular                                  // ?: non-regular file; nothing else is known about this file
+	ModeDir        = fs.ModeDir        // d: is a directory
+	ModeAppend     = fs.ModeAppend     // a: append-only
+	ModeExclusive  = fs.ModeExclusive  // l: exclusive use
+	ModeTemporary  = fs.ModeTemporary  // T: temporary file; Plan 9 only
+	ModeSymlink    = fs.ModeSymlink    // L: symbolic link
+	ModeDevice     = fs.ModeDevice     // D: device file
+	ModeNamedPipe  = fs.ModeNamedPipe  // p: named pipe (FIFO)
+	ModeSocket     = fs.ModeSocket     // S: Unix domain socket
+	ModeSetuid     = fs.ModeSetuid     // u: setuid
+	ModeSetgid     = fs.ModeSetgid     // g: setgid
+	ModeCharDevice = fs.ModeCharDevice // c: Unix character device, when ModeDevice is set
+	ModeSticky     = fs.ModeSticky     // t: sticky
+	ModeIrregular  = fs.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 | ModeCharDevice | ModeIrregular
+	ModeType = fs.ModeType
 
-	ModePerm FileMode = 0777 // Unix permission bits
+	ModePerm = fs.ModePerm // Unix permission bits, 0o777
 )
 
-func (m FileMode) String() string {
-	const str = "dalTLDpSugct?"
-	var buf [32]byte // Mode is uint32.
-	w := 0
-	for i, c := range str {
-		if m&(1<<uint(32-1-i)) != 0 {
-			buf[w] = byte(c)
-			w++
-		}
-	}
-	if w == 0 {
-		buf[w] = '-'
-		w++
-	}
-	const rwx = "rwxrwxrwx"
-	for i, c := range rwx {
-		if m&(1<<uint(9-1-i)) != 0 {
-			buf[w] = byte(c)
-		} else {
-			buf[w] = '-'
-		}
-		w++
-	}
-	return string(buf[:w])
-}
-
-// IsDir reports whether m describes a directory.
-// That is, it tests for the ModeDir bit being set in m.
-func (m FileMode) IsDir() bool {
-	return m&ModeDir != 0
-}
-
-// IsRegular reports whether m describes a regular file.
-// That is, it tests that no mode type bits are set.
-func (m FileMode) IsRegular() bool {
-	return m&ModeType == 0
-}
-
-// Perm returns the Unix permission bits in m.
-func (m FileMode) Perm() FileMode {
-	return m & ModePerm
-}
-
 func (fs *fileStat) Name() string { return fs.name }
 func (fs *fileStat) IsDir() bool  { return fs.Mode().IsDir() }
 
diff --git a/libgo/go/os/types_windows.go b/libgo/go/os/types_windows.go
index 3d1a667..59bf5ca 100644
--- a/libgo/go/os/types_windows.go
+++ b/libgo/go/os/types_windows.go
@@ -45,7 +45,7 @@ func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (f
 	var d syscall.ByHandleFileInformation
 	err = syscall.GetFileInformationByHandle(h, &d)
 	if err != nil {
-		return nil, &PathError{"GetFileInformationByHandle", path, err}
+		return nil, &PathError{Op: "GetFileInformationByHandle", Path: path, Err: err}
 	}
 
 	var ti windows.FILE_ATTRIBUTE_TAG_INFO
@@ -58,7 +58,7 @@ func newFileStatFromGetFileInformationByHandle(path string, h syscall.Handle) (f
 			// instance to indicate no symlinks are possible.
 			ti.ReparseTag = 0
 		} else {
-			return nil, &PathError{"GetFileInformationByHandleEx", path, err}
+			return nil, &PathError{Op: "GetFileInformationByHandleEx", Path: path, Err: err}
 		}
 	}
 
@@ -197,7 +197,7 @@ func (fs *fileStat) saveInfoFromPath(path string) error {
 		var err error
 		fs.path, err = syscall.FullPath(fs.path)
 		if err != nil {
-			return &PathError{"FullPath", path, err}
+			return &PathError{Op: "FullPath", Path: path, Err: err}
 		}
 	}
 	fs.name = basename(path)
diff --git a/libgo/go/os/user/lookup_plan9.go b/libgo/go/os/user/lookup_plan9.go
index ea3ce0b..33ae3a6 100644
--- a/libgo/go/os/user/lookup_plan9.go
+++ b/libgo/go/os/user/lookup_plan9.go
@@ -6,7 +6,6 @@ package user
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"syscall"
 )
@@ -23,7 +22,7 @@ func init() {
 }
 
 func current() (*User, error) {
-	ubytes, err := ioutil.ReadFile(userFile)
+	ubytes, err := os.ReadFile(userFile)
 	if err != nil {
 		return nil, fmt.Errorf("user: %s", err)
 	}