testConfig.Certificates[1].PrivateKey = testRSAPrivateKey
	testConfig.BuildNameToCertificate()
	if *keyFile != "" {
		f, err := os.OpenFile(*keyFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
		if err != nil {
			panic("failed to open -keylog file: " + err.Error())
		}
		testConfig.KeyLogWriter = f
		defer f.Close()
	}

	return m.Run()
}

	r, err := c.osInterface.Open(log)
	if err != nil {
		return fmt.Errorf("failed to open log %q: %v", log, err)
	}
	defer r.Close()
	tmpLog := log + tmpSuffix
	f, err := c.osInterface.OpenFile(tmpLog, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
	if err != nil {
		return fmt.Errorf("failed to create temporary log %q: %v", tmpLog, err)
	}
	defer func() {
		// Best effort cleanup of tmpLog.
		c.osInterface.Remove(tmpLog)

	bakname, err := backupFile(filename, orig, perm)
	if err != nil {
		return err
	}

	fdSem <- true
	defer func() { <-fdSem }()

	fout, err := os.OpenFile(filename, os.O_WRONLY, perm)
	if err != nil {
		// We couldn't even open the file, so it should
		// not have changed.
		os.Remove(bakname)
		return err
	}
	defer fout.Close() // for error paths

	for _, pattern := range patterns {
		out = append(out, regexp.MustCompile(pattern))
	}

	return out
}

func appendToFile(contents []byte, file string) error {
	f, err := os.OpenFile(file, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0o600)
	if err != nil {
		return err
	}

	defer func() {
		_ = f.Close()
	}()

	if _, err = f.Write(contents); err != nil {
		return err
	}
	return nil

(() => {
	const enosys = () => {
		const err = new Error("not implemented");
		err.code = "ENOSYS";
		return err;
	};

	if (!globalThis.fs) {
		let outputBuf = "";
		globalThis.fs = {
			constants: { O_WRONLY: -1, O_RDWR: -1, O_CREAT: -1, O_TRUNC: -1, O_APPEND: -1, O_EXCL: -1 }, // unused
			writeSync(fd, buf) {
				outputBuf += decoder.decode(buf);
				const nl = outputBuf.lastIndexOf("\n");
				if (nl != -1) {

	WSAENOPROTOOPT            Errno = 10042
	WSAECONNABORTED           Errno = 10053
	WSAECONNRESET             Errno = 10054
)

const (
	// Invented values to support what package os expects.
	O_RDONLY   = 0x00000
	O_WRONLY   = 0x00001
	O_RDWR     = 0x00002
	O_CREAT    = 0x00040
	O_EXCL     = 0x00080
	O_NOCTTY   = 0x00100
	O_TRUNC    = 0x00200
	O_NONBLOCK = 0x00800
	O_APPEND   = 0x00400
	O_SYNC     = 0x01000

}

func Chown(path string, uid int, gid int) (err error) {
	return Fchownat(AT_FDCWD, path, uid, gid, 0)
}

func Creat(path string, mode uint32) (fd int, err error) {
	return Open(path, O_CREAT|O_WRONLY|O_TRUNC, mode)
}

//sys	utimes(path string, times *[2]Timeval) (err error)

func Utimes(path string, tv []Timeval) error {
	if len(tv) != 2 {
		return EINVAL
	}

// operations.
func scanOneLun(hostNumber int, lunNumber int) error {
	filename := fmt.Sprintf("/sys/class/scsi_host/host%d/scan", hostNumber)
	fd, err := os.OpenFile(filename, os.O_WRONLY, 0)
	if err != nil {
		return err
	}
	defer fd.Close()

	// Channel/Target are always 0 for iSCSI
	scanCmd := fmt.Sprintf("0 0 %d", lunNumber)
	if written, err := fd.WriteString(scanCmd); err != nil {

		// we need to ensure that only the temporary copy is affected.
		s, err := os.Open(src)
		if err != nil {
			return err
		}
		defer s.Close()
		d, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
		if err != nil {
			return err
		}
		_, err = io.Copy(d, s)
		if err != nil {
			d.Close()
			return err
		}
		return d.Close()
	})
	if err != nil {

		AssertNotRebuilt(t, "new .a file", target)
		AssertRebuilt(t, "new .a file", shlib)
	})
}

func appendFile(t *testing.T, path, content string) {
	t.Helper()
	f, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND, 0660)
	if err != nil {
		t.Fatalf("os.OpenFile failed: %v", err)
	}
	defer func() {
		err := f.Close()
		if err != nil {
			t.Fatalf("f.Close failed: %v", err)
		}
	}()