diff --git a/cl/import.go b/cl/import.go
index 031b1b46..5d9b8b25 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -532,7 +532,7 @@ func ignoreName(name string) bool {
 func supportedInternal(name string) bool {
 	return strings.HasPrefix(name, "abi.") || strings.HasPrefix(name, "bytealg.") ||
 		strings.HasPrefix(name, "oserror.") || strings.HasPrefix(name, "reflectlite.") ||
-		strings.HasPrefix(name, "syscall/execenv.")
+		strings.HasPrefix(name, "syscall/unix.") || strings.HasPrefix(name, "syscall/execenv.")
 }
 
 // -----------------------------------------------------------------------------
diff --git a/internal/build/build.go b/internal/build/build.go
index 1f8e26d3..0d2165e5 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -753,6 +753,7 @@ var hasAltPkg = map[string]none{
 	"internal/oserror":         {},
 	"internal/reflectlite":     {},
 	"internal/syscall/execenv": {},
+	"internal/syscall/unix":    {},
 	"math":                     {},
 	"math/cmplx":               {},
 	"reflect":                  {},
diff --git a/internal/lib/internal/syscall/unix/nonblocking_js.go b/internal/lib/internal/syscall/unix/nonblocking_js.go
new file mode 100644
index 00000000..cfe78c58
--- /dev/null
+++ b/internal/lib/internal/syscall/unix/nonblocking_js.go
@@ -0,0 +1,15 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build js && wasm
+
+package unix
+
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	return false, nil
+}
+
+func HasNonblockFlag(flag int) bool {
+	return false
+}
diff --git a/internal/lib/internal/syscall/unix/nonblocking_unix.go b/internal/lib/internal/syscall/unix/nonblocking_unix.go
new file mode 100644
index 00000000..10f43d56
--- /dev/null
+++ b/internal/lib/internal/syscall/unix/nonblocking_unix.go
@@ -0,0 +1,23 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix
+
+package unix
+
+import "github.com/goplus/llgo/c/syscall"
+
+/* TODO(xsw):
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	flag, e1 := Fcntl(fd, syscall.F_GETFL, 0)
+	if e1 != nil {
+		return false, e1
+	}
+	return flag&syscall.O_NONBLOCK != 0, nil
+}
+*/
+
+func HasNonblockFlag(flag int) bool {
+	return flag&syscall.O_NONBLOCK != 0
+}
diff --git a/internal/lib/internal/syscall/unix/nonblocking_wasip1.go b/internal/lib/internal/syscall/unix/nonblocking_wasip1.go
new file mode 100644
index 00000000..8f808207
--- /dev/null
+++ b/internal/lib/internal/syscall/unix/nonblocking_wasip1.go
@@ -0,0 +1,37 @@
+// Copyright 2023 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.
+
+//go:build wasip1
+
+package unix
+
+import "github.com/goplus/llgo/c/syscall"
+
+/* TODO(xsw):
+import (
+	"syscall"
+	_ "unsafe" // for go:linkname
+)
+
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	flags, e1 := fd_fdstat_get_flags(fd)
+	if e1 != nil {
+		return false, e1
+	}
+	return flags&syscall.FDFLAG_NONBLOCK != 0, nil
+}
+*/
+
+func HasNonblockFlag(flag int) bool {
+	return flag&syscall.FDFLAG_NONBLOCK != 0
+}
+
+/* TODO(xsw):
+// This helper is implemented in the syscall package. It means we don't have
+// to redefine the fd_fdstat_get host import or the fdstat struct it
+// populates.
+//
+//-go:linkname fd_fdstat_get_flags syscall.fd_fdstat_get_flags
+func fd_fdstat_get_flags(fd int) (uint32, error)
+*/
diff --git a/internal/lib/internal/syscall/unix/unix.go b/internal/lib/internal/syscall/unix/unix.go
new file mode 100644
index 00000000..8b0cffd8
--- /dev/null
+++ b/internal/lib/internal/syscall/unix/unix.go
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2024 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package unix
+
+// llgo:skipall
+import (
+	_ "unsafe"
+)
diff --git a/internal/lib/os/file.go b/internal/lib/os/file.go
index a48f759b..5b309661 100644
--- a/internal/lib/os/file.go
+++ b/internal/lib/os/file.go
@@ -208,7 +208,6 @@ func (f *File) WriteString(s string) (n int, err error) {
 	panic("todo: os.(*File).WriteString")
 }
 
-/*
 // setStickyBit adds ModeSticky to the permission bits of path, non atomic.
 func setStickyBit(name string) error {
 	fi, err := Stat(name)
@@ -217,7 +216,6 @@ func setStickyBit(name string) error {
 	}
 	return Chmod(name, fi.Mode()|ModeSticky)
 }
-*/
 
 // Open opens the named file for reading. If successful, methods on
 // the returned file can be used for reading; the associated file
diff --git a/internal/lib/os/file_posix.go b/internal/lib/os/file_posix.go
index 7877a6aa..03f1806c 100644
--- a/internal/lib/os/file_posix.go
+++ b/internal/lib/os/file_posix.go
@@ -48,7 +48,6 @@ func (f *File) pwrite(b []byte, off int64) (n int, err error) {
 	panic("todo: os.(*File).pwrite")
 }
 
-/*
 // syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
 func syscallMode(i FileMode) (o uint32) {
 	o |= uint32(i.Perm())
@@ -65,6 +64,7 @@ func syscallMode(i FileMode) (o uint32) {
 	return
 }
 
+/* TODO(xsw):
 // See docs in file.go:Chmod.
 func chmod(name string, mode FileMode) error {
 	longName := fixLongPath(name)
diff --git a/internal/lib/os/file_unix.go b/internal/lib/os/file_unix.go
index fe390562..918890a0 100644
--- a/internal/lib/os/file_unix.go
+++ b/internal/lib/os/file_unix.go
@@ -8,6 +8,9 @@ package os
 
 import (
 	"runtime"
+	"syscall"
+
+	"github.com/goplus/llgo/internal/lib/internal/syscall/unix"
 )
 
 // Fd returns the integer Unix file descriptor referencing the open file.
@@ -30,15 +33,6 @@ func (f *File) Fd() uintptr {
 	return f.fd
 }
 
-// NewFile returns a new File with the given file descriptor and
-// name. The returned value will be nil if fd is not a valid file
-// descriptor. On Unix systems, if the file descriptor is in
-// non-blocking mode, NewFile will attempt to return a pollable File
-// (one for which the SetDeadline methods work).
-//
-// After passing it to NewFile, fd may become invalid under the same
-// conditions described in the comments of the Fd method, and the same
-// constraints apply.
 func NewFile(fd uintptr, name string) *File {
 	return &File{fd: fd, name: name}
 }
@@ -113,6 +107,83 @@ const (
 	kindNoPoll
 )
 
+// newFile is like NewFile, but if called from OpenFile or Pipe
+// (as passed in the kind parameter) it tries to add the file to
+// the runtime poller.
+func newFile(fd int, name string, kind newFileKind) *File {
+	f := &File{
+		fd:          uintptr(fd),
+		name:        name,
+		stdoutOrErr: fd == 1 || fd == 2,
+	}
+
+	/* TODO(xsw):
+	pollable := kind == kindOpenFile || kind == kindPipe || kind == kindNonBlock
+
+	// If the caller passed a non-blocking filedes (kindNonBlock),
+	// we assume they know what they are doing so we allow it to be
+	// used with kqueue.
+	if kind == kindOpenFile {
+		switch runtime.GOOS {
+		case "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd":
+			var st syscall.Stat_t
+			err := ignoringEINTR(func() error {
+				return syscall.Fstat(fd, &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
+			// reported as ready for writing.
+			// On Dragonfly, NetBSD and OpenBSD the fd is signaled
+			// only once as ready (both read and write).
+			// Issue 19093.
+			// Also don't add directories to the netpoller.
+			if err == nil && (typ == syscall.S_IFREG || typ == syscall.S_IFDIR) {
+				pollable = false
+			}
+
+			// In addition to the behavior described above for regular files,
+			// on Darwin, kqueue does not work properly with fifos:
+			// closing the last writer does not cause a kqueue event
+			// for any readers. See issue #24164.
+			if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && typ == syscall.S_IFIFO {
+				pollable = false
+			}
+		}
+	}
+
+	clearNonBlock := false
+	if pollable {
+		if kind == kindNonBlock {
+			// The descriptor is already in non-blocking mode.
+			// We only set f.nonblock if we put the file into
+			// non-blocking mode.
+		} else if err := syscall.SetNonblock(fd, true); err == nil {
+			f.nonblock = true
+			clearNonBlock = true
+		} else {
+			pollable = false
+		}
+	}
+
+	// An error here indicates a failure to register
+	// with the netpoll system. That can happen for
+	// a file descriptor that is not supported by
+	// epoll/kqueue; for example, disk files on
+	// Linux systems. We assume that any real error
+	// will show up in later I/O.
+	// We do restore the blocking behavior if it was set by us.
+	if pollErr := f.pfd.Init("file", pollable); pollErr != nil && clearNonBlock {
+		if err := syscall.SetNonblock(fd, false); err == nil {
+			f.nonblock = false
+		}
+	}
+
+	runtime.SetFinalizer(f.file, (*file).close)
+	*/
+	return f
+}
+
 // TODO(xsw):
 // func sigpipe() // implemented in package runtime
 
@@ -135,7 +206,48 @@ const DevNull = "/dev/null"
 // openFileNolog is the Unix implementation of OpenFile.
 // Changes here should be reflected in openFdAt, if relevant.
 func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
-	panic("todo: os.openFileNolog")
+	setSticky := false
+	if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
+		if _, err := Stat(name); IsNotExist(err) {
+			setSticky = true
+		}
+	}
+
+	var r int
+	for {
+		var e error
+		r, e = syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
+		if e == nil {
+			break
+		}
+
+		// We have to check EINTR here, per issues 11180 and 39237.
+		if e == syscall.EINTR {
+			continue
+		}
+
+		return nil, &PathError{Op: "open", Path: name, Err: e}
+	}
+
+	// open(2) itself won't handle the sticky bit on *BSD and Solaris
+	if setSticky {
+		setStickyBit(name)
+	}
+
+	// There's a race here with fork/exec, which we are
+	// content to live with. See ../syscall/exec_unix.go.
+	if !supportsCloseOnExec {
+		syscall.CloseOnExec(r)
+	}
+
+	kind := kindOpenFile
+	if unix.HasNonblockFlag(flag) {
+		kind = kindNonBlock
+		panic("todo: os.openFileNolog: unix.HasNonblockFlag")
+	}
+
+	f := newFile(r, name, kind)
+	return f, nil
 }
 
 func tempDir() string {
diff --git a/internal/lib/os/sticky_bsd.go b/internal/lib/os/sticky_bsd.go
new file mode 100644
index 00000000..a6d93395
--- /dev/null
+++ b/internal/lib/os/sticky_bsd.go
@@ -0,0 +1,11 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || (js && wasm) || netbsd || openbsd || solaris || wasip1
+
+package os
+
+// According to sticky(8), neither open(2) nor mkdir(2) will create
+// a file with the sticky bit set.
+const supportsCreateWithStickyBit = false
diff --git a/internal/lib/os/sticky_nonbsd.go b/internal/lib/os/sticky_nonbsd.go
new file mode 100644
index 00000000..1d289b0f
--- /dev/null
+++ b/internal/lib/os/sticky_nonbsd.go
@@ -0,0 +1,9 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !js && !netbsd && !openbsd && !solaris && !wasip1
+
+package os
+
+const supportsCreateWithStickyBit = true
diff --git a/internal/lib/os/sys_js.go b/internal/lib/os/sys_js.go
new file mode 100644
index 00000000..4fd0e2d7
--- /dev/null
+++ b/internal/lib/os/sys_js.go
@@ -0,0 +1,11 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build js && wasm
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+const supportsCloseOnExec = false
diff --git a/internal/lib/os/sys_unix.go b/internal/lib/os/sys_unix.go
new file mode 100644
index 00000000..79005c2c
--- /dev/null
+++ b/internal/lib/os/sys_unix.go
@@ -0,0 +1,14 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+// On Darwin, the O_CLOEXEC flag was introduced in OS X 10.7 (Darwin 11.0.0).
+// See https://support.apple.com/kb/HT1633.
+// On FreeBSD, the O_CLOEXEC flag was introduced in version 8.3.
+const supportsCloseOnExec = true
diff --git a/internal/lib/os/sys_wasip1.go b/internal/lib/os/sys_wasip1.go
new file mode 100644
index 00000000..5a29aa53
--- /dev/null
+++ b/internal/lib/os/sys_wasip1.go
@@ -0,0 +1,11 @@
+// Copyright 2023 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.
+
+//go:build wasip1
+
+package os
+
+// supportsCloseOnExec reports whether the platform supports the
+// O_CLOEXEC flag.
+const supportsCloseOnExec = false
diff --git a/internal/lib/os/types.go b/internal/lib/os/types.go
index 40a66ae4..af840c98 100644
--- a/internal/lib/os/types.go
+++ b/internal/lib/os/types.go
@@ -19,10 +19,11 @@ func Getpagesize() int { return syscall.Getpagesize() }
 
 // File represents an open file descriptor.
 type File struct {
-	fd         uintptr
-	name       string
-	appendMode bool
-	nonblock   bool
+	fd          uintptr
+	name        string
+	appendMode  bool
+	nonblock    bool
+	stdoutOrErr bool
 }
 
 // write writes len(b) bytes to the File.