ErrBadName   = errors.New("bad character in file name")
)

// A Qid represents a 9P server's unique identification for a file.
type Qid struct {
	Path uint64 // the file server's unique identification for the file
	Vers uint32 // version number for given Path
	Type uint8  // the type of the file (plan9.QTDIR for example)
}

// A Dir contains the metadata for a file.
type Dir struct {
	// system-modified data

// binaries built with module support.
func Read(r io.ReaderAt) (*BuildInfo, error) {
	vers, mod, err := readRawBuildInfo(r)
	if err != nil {
		return nil, err
	}
	bi, err := debug.ParseBuildInfo(mod)
	if err != nil {
		return nil, err
	}
	bi.GoVersion = vers
	return bi, nil
}

type exe interface {
	// ReadData reads and returns up to size bytes starting at virtual address addr.

	if err != nil {
		t.Logf("%s", verout)
		t.Fatal(err)
	}
	vers := regexp.MustCompile(`(\d+)\.(\d+)`).FindSubmatch(verout)
	if len(vers) == 0 {
		t.Fatalf("could not find version number in %s", verout)
	}
	major, err := strconv.Atoi(string(vers[1]))
	if err != nil {
		t.Fatal(err)
	}
	minor, err := strconv.Atoi(string(vers[2]))
	if err != nil {
		t.Fatal(err)
	}

// and fetch new records as needed by calling gosum.
func NewTestServer(signer string, gosum func(path, vers string) ([]byte, error)) *TestServer {
	return &TestServer{signer: signer, gosum: gosum}
}

// A TestServer is an in-memory implementation of [ServerOps] for testing.
type TestServer struct {
	signer string
	gosum  func(path, vers string) ([]byte, error)

	mu      sync.Mutex
	hashes  testHashes
	records [][]byte

			// encoded in the debugging information entry itself.
			val = true

		// reference to other entry
		case formRefAddr:
			vers := b.format.version()
			if vers == 0 {
				b.error("unknown version for DW_FORM_ref_addr")
			} else if vers == 2 {
				val = Offset(b.addr())
			} else {
				is64, known := b.format.dwarf64()
				if !known {
					b.error("unknown size for DW_FORM_ref_addr")

	}

	d := &Data{}
	d.order = binary.LittleEndian
	if err := d.AddSection(".debug_rnglists", rngLists); err != nil {
		t.Fatal(err)
	}
	u := &unit{
		asize: 8,
		vers:  5,
		is64:  true,
	}
	ret, err := d.dwarf5Ranges(u, nil, 0x5fbd, 0xc, [][2]uint64{})
	if err != nil {
		t.Fatalf("could not read rnglist: %v", err)
	}
	t.Logf("%#v", ret)

	c := hs.c

	hs.hello = new(serverHelloMsg)

	// TLS 1.3 froze the ServerHello.legacy_version field, and uses
	// supported_versions instead. See RFC 8446, sections 4.1.3 and 4.2.1.
	hs.hello.vers = VersionTLS12
	hs.hello.supportedVersion = c.vers

	if len(hs.clientHello.supportedVersions) == 0 {
		c.sendAlert(alertIllegalParameter)
		return errors.New("tls: client used the legacy version field to negotiate TLS 1.3")
	}

// versions that support signature algorithms, so TLS 1.2 and 1.3.
func selectSignatureScheme(vers uint16, c *Certificate, peerAlgs []SignatureScheme) (SignatureScheme, error) {
	supportedAlgs := signatureSchemesForCertificate(vers, c)
	if len(supportedAlgs) == 0 {
		return 0, unsupportedCertificateError(c)
	}
	if len(peerAlgs) == 0 && vers == VersionTLS12 {
		// For TLS 1.2, if the client didn't send signature_algorithms then we

		if cfg.CmdName != "mod download" {
			vers := mod.Version
			if mod.Path == "golang.org/toolchain" {
				// Shorten v0.0.1-go1.13.1.darwin-amd64 to go1.13.1.darwin-amd64
				_, vers, _ = strings.Cut(vers, "-")
				if i := strings.LastIndex(vers, "."); i >= 0 {
					goos, goarch, _ := strings.Cut(vers[i+1:], "-")
					vers = vers[:i] + " (" + goos + "/" + goarch + ")"
				}

			if !extData.ReadUint8LengthPrefixed(&versList) || versList.Empty() {
				return false
			}
			for !versList.Empty() {
				var vers uint16
				if !versList.ReadUint16(&vers) {
					return false
				}
				m.supportedVersions = append(m.supportedVersions, vers)
			}
		case extensionCookie:
			// RFC 8446, Section 4.2.2
			if !readUint16LengthPrefixed(&extData, &m.cookie) ||
				len(m.cookie) == 0 {