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

	// with mode 0o777 mkdir honors system umask.
	mkdirAll(pathutil.Dir(filePath), 0o777, s.drivePath) // don't need to fail here

	w, err := s.openFileDirect(filePath, os.O_CREATE|os.O_WRONLY|os.O_EXCL)
	if err != nil {
		return err
	}
	_, err = w.Write(alignedBuf)
	w.Close()
	if err != nil {
		if isSysErrInvalidArg(err) {
			err = errUnsupportedDisk
		}
	}
	return err
}

	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

		// 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 {

	src, err := os.Open(os.Args[0])
	if err != nil {
		t.Fatalf("cannot open binary %q, %v", os.Args[0], err)
	}
	defer src.Close()

	dst, err := os.OpenFile(tmpBinary, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0755)
	if err != nil {
		t.Fatalf("cannot create temporary binary %q, %v", tmpBinary, err)
	}
	if _, err := io.Copy(dst, src); err != nil {

			panic(msg)
		}
	}
	file := c.fileName(id, "a")

	// Copy file to cache directory.
	mode := os.O_WRONLY | os.O_CREATE
	f, err := os.OpenFile(file, mode, 0666)
	if err != nil {
		return err
	}
	_, err = f.WriteString(entry)
	if err == nil {
		// Truncate the file only *after* writing it.

	O_NONBLOCK                      = 0x04
	O_RDONLY                        = 0x02
	O_RDWR                          = 0x03
	O_SYNC                          = 0x0100
	O_TRUNC                         = 0x10
	O_WRONLY                        = 0x01
	O_NOCTTY                        = 0x20
	OPOST                           = 0x0001
	ONLCR                           = 0x0004
	PARENB                          = 0x0200