Golang Buffer.String方法代码示例

func faiConnection(conn *net.TCPConn) {
	defer conn.Close()
	var err error

	err = conn.SetKeepAlive(true)
	if err != nil {
		util.Log(0, "ERROR! SetKeepAlive: %v", err)
	}

	var buf bytes.Buffer
	defer buf.Reset()
	readbuf := make([]byte, 4096)
	n := 1
	for n != 0 {
		n, err = conn.Read(readbuf)
		if err != nil && err != io.EOF {
			util.Log(0, "ERROR! Read: %v", err)
		}
		if n == 0 && err == nil {
			util.Log(0, "ERROR! Read 0 bytes but no error reported")
		}

		// Find complete lines terminated by '\n' and process them.
		for start := 0; ; {
			eol := start
			for ; eol < n; eol++ {
				if readbuf[eol] == '\n' {
					break
				}
			}

			// no \n found, append to buf and continue reading
			if eol == n {
				buf.Write(readbuf[start:n])
				break
			}

			// append to rest of line to buffered contents
			buf.Write(readbuf[start:eol])
			start = eol + 1

			buf.TrimSpace()

			util.Log(2, "DEBUG! FAI monitor message from %v: %v", conn.RemoteAddr(), buf.String())
			buf.Reset()
		}
	}

	if buf.Len() != 0 {
		util.Log(2, "DEBUG! Incomplete FAI monitor message (i.e. not terminated by \"\\n\") from %v: %v", conn.RemoteAddr(), buf.String())
	}
}

func main() {
	if len(os.Args) != 3 && len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, "USAGE: %v", USAGE)
		os.Exit(0)
	}

	var input bytes.Buffer
	defer input.Reset()
	if len(os.Args) == 3 {
		input.WriteString(os.Args[2])
	} else {
		buf, err := ioutil.ReadAll(os.Stdin)
		if err != nil {
			fmt.Fprintf(os.Stderr, "%v", err)
			os.Exit(1)
		}
		input.Write(buf)
	}
	security.GosaEncryptBuffer(&input, os.Args[1])
	fmt.Fprintln(os.Stdout, input.String())
}

// Converts LDIF data into a Hash. The outermost tag will always be "xml".
// If an error occurs the returned Hash may contain partial data but it
// is never nil.
//
//  itemtag: If non-empty, each object in the LDIF will be inside an element
//           whose outermosttag is itemtag. If itemtag == "", all objects in the
//           LDIF are merged, i.e. all their combined attributes are directly
//           inside the surrounding "xml" tag.
//  casefold: If true, all attribute names are converted to lowercase.
//            If false, they are left exactly as found in the LDIF.
//  ldif: A []byte, string, io.Reader or *exec.Cmd that provides the LDIF data.
//        Understands all ldapsearch formats with an arbitrary number of "-L" switches.
//  elementInfo: If one or more ElementInfo structs are passed, only attributes
//        matching one of them will be accepted and the first match in the
//        elementInfo list determines how the attribute in the LDIF will be
//        converted to an element in the result Hash.
//        If casefold==true, matching is done case-insensitive. This requires that
//        the LDIFAttributeName fields are all lowercase.
func LdifToHash(itemtag string, casefold bool, ldif interface{}, elementInfo ...*ElementInfo) (xml *Hash, err error) {
	x := NewHash("xml")

	var xmldata []byte
	switch ld := ldif.(type) {
	case []byte:
		xmldata = ld
	case string:
		xmldata = []byte(ld)
	case io.Reader:
		xmldata, err = ioutil.ReadAll(ld)
		if err != nil {
			return x, err
		}
	case *exec.Cmd:
		var outbuf bytes.Buffer
		defer outbuf.Reset()
		var errbuf bytes.Buffer
		defer errbuf.Reset()
		oldout := ld.Stdout
		olderr := ld.Stderr
		ld.Stdout = &outbuf
		ld.Stderr = &errbuf
		err := ld.Run()
		ld.Stdout = oldout
		ld.Stderr = olderr
		errstr := errbuf.String()
		if errstr != "" {
			err = fmt.Errorf(errstr)
		}
		if err != nil {
			return x, err
		}

		xmldata = outbuf.Bytes()
	default:
		return x, fmt.Errorf("ldif argument has unsupported type")
	}

	item := x
	var attr *Hash
	new_item := true
	end := len(xmldata)
	b64 := false
	var info *ElementInfo = nil
	skip := false

	i := 0
	start := 0
	if !match(xmldata, i, "version:") {
		goto wait_for_item
	}

	///////////////////////////////////////////////////////////////////////
skip_line:
	///////////////////////////////////////////////////////////////////////
	for {
		if i == end {
			goto end_of_input
		}
		if xmldata[i] == '\n' {
			break
		}
		i++
	}
	// Even comments can have line continuations in LDIF, so we need to
	// continue skipping if there is a continuation.
	i++
	if i < end && (xmldata[i] == ' ' || xmldata[i] == '\t') {
		goto skip_line
	}

	///////////////////////////////////////////////////////////////////////
wait_for_item:
	///////////////////////////////////////////////////////////////////////
	new_item = true
	for {
		if i == end {
			goto end_of_input
		}
		if ch := xmldata[i]; ch > ' ' {
			if match(xmldata, i, "# search result") {
//.........这里部分代码省略.........

// Executes program and reads from its standard output log files to transfer to
// the target server. See fai-savelog-hook in the manual.
func Send_clmsg_save_fai_log(target string, program string) {
	var buffy bytes.Buffer
	defer buffy.Reset()

	clientpackageskey := config.ModuleKey["[ClientPackages]"]
	// If [ClientPackages]/key missing, take the last key in the list
	// (We don't take the 1st because that would be "dummy-key").
	if clientpackageskey == "" {
		clientpackageskey = config.ModuleKeys[len(config.ModuleKeys)-1]
	}

	util.Log(1, "INFO! Launching fai-savelog-hook %v", program)
	start := time.Now()
	env := config.HookEnvironment()
	cmd := exec.Command(program)
	cmd.Env = append(env, os.Environ()...)

	out, err := cmd.StdoutPipe()
	if err != nil {
		util.Log(0, "ERROR! Could not get stdout pipe for %v: %v", program, err)
		return
	}
	defer out.Close()

	in, err := cmd.StdinPipe()
	if err != nil {
		util.Log(0, "ERROR! Could not get stdin pipe for %v: %v", program, err)
		return
	}
	defer in.Close()

	err = cmd.Start()
	if err != nil {
		util.Log(0, "ERROR! Could not launch %v: %v", program, err)
		return
	}

	buffy.WriteString("<xml><header>CLMSG_save_fai_log</header><source>")
	buffy.WriteString(config.ServerSourceAddress)
	buffy.WriteString("</source>")
	buffy.WriteString("<target>")
	buffy.WriteString(target)
	buffy.WriteString("</target>")
	buffy.WriteString("<macaddress>")
	buffy.WriteString(config.MAC)
	buffy.WriteString("</macaddress>")
	buffy.WriteString("<CLMSG_save_fai_log>")

	reader := bufio.NewReader(out)
	fai_action := ""
	for {
		line, err := reader.ReadString('\n')
		if err != nil {
			util.Log(0, "ERROR! Error reading stdout from %v: %v", program, err)
			return
		}

		line = strings.TrimSpace(line)
		if line == "install" || line == "softupdate" {
			fai_action = line
			break
		}

		buffy.WriteString(line)
	}

	util.Log(1, "INFO! Received %v bytes in %v from fai-savelog-hook", buffy.Len(), time.Since(start))

	buffy.WriteString("</CLMSG_save_fai_log>")
	buffy.WriteString("<fai_action>")
	buffy.WriteString(fai_action)
	buffy.WriteString("</fai_action>")
	buffy.WriteString("</xml>")

	util.Log(1, "INFO! Sending %v bytes of log files to %v", buffy.Len(), target)
	security.SendLnTo(target, buffy.String(), clientpackageskey, false)

	in.Write([]byte{'\n'}) // notify hook that transfer is complete
}

// Returns the data for the given request. request_re and reply are lists of
// equal length. If request matches request_re[i], then reply[i] specifies the
// data to return for the request. If reply[i] == "",
// then this function returns (nil,nil). If reply[i] starts with the
// character '|', the remainder is taken as the path of a hook to execute
// to generate the data. Otherwise reply[i] is taken as the path of the
// file whose contents to return as data.
//
// When executing a hook, an environment variable called "tftp_request"
// is passed containing the request string. If request_re[i] has a capturing
// group named "macaddress", the captured substring will be converted to
// a MAC address by converting to lowercase, removing all characters
// except 0-9a-f, left-padding to
// length 12 with 0s or truncating to length 12 and inserting ":"s. The
// result will be added to
// the hook environment in a variable named "macaddress" and if there
// is an LDAP object for that macaddress, its attributes will be added
// to the environment, too.
// Other named subexpressions in request_re[i] will be exported to the hook
// verbatim in like-named environment variables.
//
// ATTENTION! Do not forget to call Release() on the returned cacheEntry when you're
// done using it.
func getFile(request string, request_re []*regexp.Regexp, reply []string) (cacheEntry, error) {

	for i := range request_re {
		if subs := request_re[i].FindStringSubmatch(request); subs != nil {
			if reply[i] == "" {
				return nil, nil
			}

			if reply[i][0] != '|' { // plain file
				subsidx := request_re[i].FindStringSubmatchIndex(request)
				fpath := string(request_re[i].ExpandString(nil, reply[i], request, subsidx))
				util.Log(1, "INFO! TFTP mapping \"%v\" => \"%v\"", request, fpath)

				// We use fpath as cache key instead of request because
				// multiple requests may map to the same fpath and we want to avoid
				// caching the same file multiple times.
				entry := getCacheEntry(fpath, 60*time.Second)

				entry.Mutex.Lock()
				defer entry.Mutex.Unlock()

				if entry.LoadCount == 0 {
					file, err := os.Open(fpath)
					entry.Err = err
					if err == nil {
						defer file.Close()

						buffy := make([]byte, 65536)
						for {
							n, err := file.Read(buffy)
							entry.Data.Write(buffy[0:n])
							if err == io.EOF {
								break
							}
							if err != nil {
								entry.Data.Reset()
								entry.Err = err
							}
							if n == 0 {
								util.Log(0, "WARNING! Read returned 0 bytes but no error. Assuming EOF")
								break
							}
						}
					}
				} else {
					util.Log(1, "INFO! TFTP: Serving %v from cache", fpath)
				}

				entry.LoadCount++

				return entry, entry.Err

			} else { // hook
				hook := reply[i][1:] // cut off '|'

				// We need a few seconds afterlife to deal with multiple requests in
				// short succession by the same loader due to delayed UDP packets.
				entry := getCacheEntry(request, 5*time.Second)

				entry.Mutex.Lock()
				defer entry.Mutex.Unlock()

				if entry.LoadCount == 0 {
					util.Log(1, "INFO! TFTP: Calling %v to generate %v", hook, request)

					env := config.HookEnvironment()
					env = append(env, "tftp_request="+request)

					for k, varname := range request_re[i].SubexpNames() {
						if varname == "" {
							continue
						}

						value := subs[k]

						if varname == "macaddress" {
							format_mac := func(r rune) rune {
//.........这里部分代码省略.........

func testBuffer() {
	var b bytes.Buffer
	check(b.String(), "") // String() on fresh variable
	b.Reset()             // Reset() on fresh variable
	check(b.String(), "") // String() after Reset()
	b.Reset()             // Reset() after Reset()
	check(b.String(), "")
	check(b.Len(), 0)

	// same tests as above with pointer
	b2 := &bytes.Buffer{}
	check(b2.String(), "")
	b2.Reset()
	check(b2.String(), "")
	b2.Reset()
	check(b2.String(), "")
	check(b2.Len(), 0)

	b2.WriteString("Dies ist ein Test!")
	check(b2.String(), "Dies ist ein Test!")
	check(b2.Len(), 18)

	n, err := b.Write(nil)
	check(n, 0)
	check(err, nil)
	check(b.String(), "")

	n, err = b.Write([]byte{})
	check(n, 0)
	check(err, nil)
	check(b.String(), "")
	check(b.Pointer(), nil)
	check(b.Capacity(), 0)
	check(b.Len(), 0)

	func() {
		defer func() {
			check(recover(), bytes.ErrTooLarge)
		}()
		b.Grow(-1)
	}()

	n, err = b.Write([]byte{'a'})
	check(n, 1)
	check(err, nil)
	check(b.String(), "a")
	check(b.Capacity() >= 1, true)
	check(b.Len(), 1)
	check(b.Pointer() != nil, true)

	check(b.Grow(11), 1)
	check(b.Capacity() >= 12, true)
	c := b.Capacity()
	p := b.Pointer()
	check(b.Grow(11), 1) // should not cause actual growth
	check(b.Pointer(), p)
	check(b.Capacity(), c)
	check(b.Len(), 1)
	((*[2]byte)(b.Pointer()))[1] = 'z'
	check(b.Contains("z"), false)

	n, err = b.WriteString("Hallo")
	check(n, 5)
	check(err, nil)
	check(b.String(), "aHallo")
	check(b.Pointer(), p)
	check(b.Capacity(), c)
	check(b.Len(), 6)

	b.Reset()
	check(b.String(), "")
	check(b.Pointer(), nil)
	check(b.Capacity(), 0)
	check(b.Contains(""), true)
	check(b.Contains("a"), false)

	b.WriteString("Hallo")
	b.WriteByte(' ')
	b.Write([]byte{'d', 'i', 'e', 's'})
	b.WriteByte(' ')
	b.WriteString("ist ")
	b.WriteString("ein ")
	b.Write([]byte("Test"))
	check(b.String(), "Hallo dies ist ein Test")
	check(b.Contains("Hallo dies ist ein Test"), true)
	check(b.Contains("Test"), true)
	check(b.Contains("Hallo"), true)
	check(b.Contains("allo"), true)
	check(b.Contains(""), true)

	check(b.Split(" "), []string{"Hallo", "dies", "ist", "ein", "Test"})
	check(b.Split("X"), []string{"Hallo dies ist ein Test"})
	check(b.Split("Hallo dies ist ein Test"), []string{"", ""})
	check(b.Split("H"), []string{"", "allo dies ist ein Test"})
	check(b.Split("Test"), []string{"Hallo dies ist ein ", ""})
	check(b.Split("es"), []string{"Hallo di", " ist ein T", "t"})

	b.Reset()
	b.WriteString("  \n\t Hallo  \t\v\n")
	check(b.Len(), 15)
//.........这里部分代码省略.........

// Reads the output from the program config.PackageListHookPath (LDIF) and
// uses it to replace packagedb.
// debconf is passed as PackageListDebconf environment var to the hook.
// See manual section on package-list-hook for more info.
func PackageListHook(debconf string) {
	start := time.Now()
	timestamp := util.MakeTimestamp(start)

	cmd := exec.Command(config.PackageListHookPath)
	cmd.Env = append(config.HookEnvironment(), os.Environ()...)

	fairepos := []string{}
	for repo := FAIServers().First("repository"); repo != nil; repo = repo.Next() {
		fairepos = append(fairepos, fmt.Sprintf("%v||%v|%v", repo.Text("server"), repo.Text("repopath"), repo.Text("sections")))
	}

	package_list_params := []string{"PackageListDebconf=" + debconf, "PackageListCacheDir=" + config.PackageCacheDir, "PackageListFAIrepository=" + strings.Join(fairepos, " ")}
	cmd.Env = append(cmd.Env, package_list_params...)
	util.Log(1, "INFO! Running package-list-hook: %v %v", strings.Join(package_list_params, " "), config.PackageListHookPath)

	var outbuf bytes.Buffer
	defer outbuf.Reset()
	var errbuf bytes.Buffer
	defer errbuf.Reset()
	cmd.Stdout = &outbuf
	cmd.Stderr = &errbuf
	err := cmd.Run()

	if err != nil {
		util.Log(0, "ERROR! package-list-hook %v: %v (%v)", config.PackageListHookPath, err, errbuf.String())
		return
	} else if errbuf.Len() != 0 {
		// if the command prints to stderr but does not return non-0 exit status (which
		// would result in err != nil), we just log a WARNING, but use the stdout data
		// anyway.
		util.Log(0, "WARNING! package-list-hook %v: %v", config.PackageListHookPath, errbuf.String())
	}

	plist, err := xml.LdifToHash("pkg", true, outbuf.Bytes(), packageListFormat...)
	if err != nil {
		util.Log(0, "ERROR! package-list-hook %v: %v", config.PackageListHookPath, err)
		return
	}
	if plist.First("pkg") == nil {
		util.Log(0, "ERROR! package-list-hook %v returned no data", config.PackageListHookPath)
		return
	}
	util.Log(1, "INFO! Finished package-list-hook. Running time: %v", time.Since(start))

	start = time.Now()

	plist.Rename("packagedb")

	new_mapRepoPath2FAIrelease := map[string]string{}

	accepted := 0
	total := 0

	for pkg := plist.FirstChild(); pkg != nil; pkg = pkg.Next() {
		total++
		p := pkg.Element()

		release := p.First("distribution") // packageListFormat translates "release" => "distribution"
		if release == nil {
			util.Log(0, "ERROR! package-list-hook %v returned entry without \"Release\": %v", config.PackageListHookPath, p)
			pkg.Remove()
			continue
		}

		for repopath := p.First("repository"); repopath != nil; repopath = repopath.Next() {
			new_mapRepoPath2FAIrelease[repopath.Text()] = release.Text()
		}

		pkgname := p.Get("package")
		if len(pkgname) == 0 {
			if p.First("repository") == nil { // Release/Repository groups without Package are okay, so only log error if there is no Repository
				util.Log(0, "ERROR! package-list-hook %v returned entry without \"Package\": %v", config.PackageListHookPath, p)
			}
			pkg.Remove()
			continue
		}

		if len(pkgname) > 1 {
			util.Log(0, "ERROR! package-list-hook %v returned entry with multiple \"Package\" values: %v", config.PackageListHookPath, p)
			pkg.Remove()
			continue
		}

		version := p.First("version")
		if version == nil {
			util.Log(0, "WARNING! package-list-hook %v returned entry for \"%v\" without \"Version\". Assuming \"1.0\"", config.PackageListHookPath, pkgname[0])
			p.Add("version", "1.0")
		}

		section := p.First("section")
		if section == nil {
			util.Log(0, "WARNING! package-list-hook %v returned entry for \"%v\" without \"Section\". Assuming \"main\"", config.PackageListHookPath, pkgname[0])
			p.Add("section", "main")
		}

//.........这里部分代码省略.........

func testLogging() {
	// Check that os.Stderr is the (only) default logger
	check(util.LoggersCount(), 1)
	util.LoggerRemove(os.Stderr)
	check(util.LoggersCount(), 0)

	// Check that default loglevel is 0
	check(util.LogLevel, 0)

	flushy := new(FlushableBuffer)
	synchy := new(SyncableBuffer)

	util.LoggerAdd(flushy)
	check(util.LoggersCount(), 1)
	util.LoggerAdd(synchy)
	check(util.LoggersCount(), 2)

	util.LogLevel = 4
	defer func() { util.LogLevel = 0 }()
	oldfac := util.BacklogFactor
	defer func() { util.BacklogFactor = oldfac }()
	util.BacklogFactor = 4

	util.Log(0, "a0") // 0
	time.Sleep(200 * time.Millisecond)
	for i := 1; i <= 4; i++ {
		util.Log(i, "a%d", i)
	} //   1,2,3,4
	for i := 0; i <= 4; i++ {
		util.Log(i, "b%d", i)
	} // 0,1,2,3
	for i := 0; i <= 4; i++ {
		util.Log(i, "c%d", i)
	} // 0,1,2
	for i := 0; i <= 4; i++ {
		util.Log(i, "d%d", i)
	} // 0,1
	for i := 0; i <= 4; i++ {
		util.Log(i, "e%d", i)
	} // 0,1
	util.Log(1, "x") // should be logged because when this Log() is executed, the backlog is only 15 long
	util.Log(1, "y") // should NOT be logged after the previous "x" the backlog is 16=4*BacklogFactor long

	check(flushy.Flushes, 0)
	check(synchy.Flushes, 0)

	time.Sleep(2 * time.Second)
	check(flushy.Flushes, 1)
	check(synchy.Flushes, 1)

	util.Log(5, "Shouldnotbelogged!")
	util.Log(4, "Shouldbelogged!")
	time.Sleep(200 * time.Millisecond)
	check(flushy.Flushes, 2)
	check(synchy.Flushes, 2)

	util.LoggersSuspend()
	check(util.LoggersCount(), 0)
	util.LoggerAdd(os.Stderr)
	check(util.LoggersCount(), 1)
	util.LoggersSuspend()
	check(util.LoggersCount(), 0)
	util.Log(0, "This should disappear in the void")
	buffy := new(bytes.Buffer)
	util.LoggerAdd(buffy)
	joke := "Sagt die Katze zum Verkäufer: Ich hab nicht genug Mäuse. Kann ich auch in Ratten zahlen?"
	util.Log(0, joke)
	time.Sleep(200 * time.Millisecond)
	check(strings.Index(buffy.String(), joke) >= 0, true)

	check(util.LoggersCount(), 1)
	util.LoggersRestore()
	check(util.LoggersCount(), 1)
	util.LoggersRestore()
	check(util.LoggersCount(), 2)

	util.Log(0, "foo")
	time.Sleep(200 * time.Millisecond)

	lines := flushy.Buf.Split("\n")
	for i := range lines {
		if strings.Index(lines[i], "missing") < 0 {
			idx := strings.LastIndex(lines[i], " ")
			lines[i] = lines[i][idx+1:]
		} else {
			idx := strings.Index(lines[i], " missing")
			lines[i] = lines[i][idx-2 : idx]
		}
	}

	check(lines, []string{"a0", "a1", "a2", "a3", "a4", "b0", "b1", "b2", "b3", "c0", "c1", "c2", "d0", "d1", "e0", "e1", "x", "10", "Shouldbelogged!", "foo", ""})

	check(flushy.Buf.String(), synchy.Buf.String())

	// Reset loggers so that only os.Stderr is a logger
	for util.LoggersCount() > 0 {
		util.LoggersRestore()
	}
	util.LoggerAdd(os.Stderr)
}

//.........这里部分代码省略.........
	check(err, nil)

	stalled1 := &stalledConnection1{}
	n, err = util.WriteAll(stalled1, buf)
	check(string(*stalled1), string(buf[0:16]))
	check(n, 16)
	check(err, io.ErrShortWrite)

	stalled2 := &stalledConnection2{}
	n, err = util.WriteAll(stalled2, buf)
	check(string(*stalled2), string(buf[0:16]))
	check(n, 16)
	check(err, io.ErrShortWrite)

	broken := &brokenConnection{}
	n, err = util.WriteAll(broken, buf)
	check(string(*broken), string(buf[0:16]))
	check(n, 16)
	check(err, io.ErrClosedPipe)

	panicker := func() {
		foobar = "bar"
		panic("foo")
	}

	var buffy bytes.Buffer
	util.LoggersSuspend()
	util.LoggerAdd(&buffy)
	defer util.LoggersRestore()

	util.WithPanicHandler(panicker)
	time.Sleep(200 * time.Millisecond) // make sure log message is written out
	check(foobar, "bar")
	check(len(buffy.String()) > 10, true)

	listener, err := net.Listen("tcp", "127.0.0.1:39390")
	if err != nil {
		panic(err)
	}

	go func() {
		r, err := listener.Accept()
		if err != nil {
			panic(err)
		}
		buf := make([]byte, 1)
		r.Read(buf)
		time.Sleep(10 * time.Second)
		r.Read(buf)
	}()
	long := make([]byte, 10000000)
	longstr := string(long)
	buffy.Reset()
	t0 := time.Now()
	util.SendLnTo("127.0.0.1:39390", longstr, 5*time.Second)
	duration := time.Since(t0)
	check(duration > 4*time.Second && duration < 6*time.Second, true)
	time.Sleep(200 * time.Millisecond) // make sure log message is written out
	check(strings.Contains(buffy.String(), "ERROR"), true)

	go func() {
		conn, err := listener.Accept()
		if err != nil {
			panic(err)
		}
		ioutil.ReadAll(conn)

// Takes a possibly encrypted message in buf and processes it, returning a reply.
// context is the security context.
// Returns:
//  buffer containing the reply to return (MUST BE FREED BY CALLER VIA Reset()!)
//  disconnect == true if connection should be terminated due to error
//
// NOTE: buf IS NOT FREED BY THIS FUNCTION BUT ITS CONTENTS ARE CHANGED!
func ProcessEncryptedMessage(buf *bytes.Buffer, context *security.Context) (reply *bytes.Buffer, disconnect bool) {
	if buf.Len() > 4096 {
		util.Log(2, "DEBUG! Processing LONG message: (truncated)%v\n.\n.\n.\n%v", string(buf.Bytes()[0:2048]), string(buf.Bytes()[buf.Len()-2048:]))
	} else {
		util.Log(2, "DEBUG! Processing message: %v", buf.String())
	}

	for attempt := 0; attempt < 4; attempt++ {
		if attempt != 0 && config.TLSRequired {
			util.Log(1, "INFO! [SECURITY] TLS-only mode => Decryption with old protocol will not be attempted")
			//NOTE: This prevents the last ditch attempt to decrypt with all known
			//      server and client keys. This attempt might still have produced a
			//      result in case the connecting party is pre-TLS and we happen to
			//      have its key in our database (from a time before our server was
			//      configured to be TLS-only). However if the admin configured our
			//      server to be TLS-only (by not putting any keys
			//      in the config) we assume that he does not want pre-TLS
			//      parties to connect.
			break
		}
		var keys_to_try []string

		switch attempt {
		case 0:
			keys_to_try = config.ModuleKeys
		case 1:
			host := context.PeerID.IP.String()
			{
				keys_to_try = append(db.ServerKeys(host), db.ClientKeys(host)...)
				if host == "127.0.0.1" { // make sure we find the key even if registered under our external IP address
					keys_to_try = append(db.ServerKeys(config.IP), db.ClientKeys(config.IP)...)
				}
			}
		case 2:
			util.Log(1, "INFO! Last resort attempt to decrypt message from %v with all server keys", context.PeerID.IP)
			keys_to_try = db.ServerKeysForAllServers()
		case 3:
			util.Log(1, "INFO! Last resort attempt to decrypt message from %v with all client keys", context.PeerID.IP)
			keys_to_try = db.ClientKeysForAllClients()
		}

		for _, key := range keys_to_try {
			if security.GosaDecryptBuffer(buf, key) {
				if buf.Len() > 4096 {
					util.Log(2, "DEBUG! Decrypted LONG message from %v with key %v: (truncated)%v\n.\n.\n.\n%v", context.PeerID.IP, key, string(buf.Bytes()[0:2048]), string(buf.Bytes()[buf.Len()-2048:]))
				} else {
					util.Log(2, "DEBUG! Decrypted message from %v with key %v: %v", context.PeerID.IP, key, buf.String())
				}

				// special case for CLMSG_save_fai_log because this kind of message
				// is so large and parsing it to XML doesn't really gain us anything.
				if buf.Contains("<CLMSG_save_fai_log>") {
					if handleServerMessage() {
						clmsg_save_fai_log(buf)
					}
					return &bytes.Buffer{}, false
				}

				xml, err := xml.StringToHash(buf.String())
				if err != nil {
					util.Log(0, "ERROR! %v", err)
					return ErrorReplyBuffer(err), true
				}

				// At this point we have successfully decrypted and parsed the message
				return ProcessXMLMessage(xml, context, key)
			}
		}
	}

	// This part is only reached if none of the keys opened the message
	util.Log(0, "ERROR! Could not decrypt message from %v", context.PeerID.IP)

	// Maybe we got out of sync with the sender's encryption key
	// (e.g. by missing a new_key message). Try to re-establish communcation.
	ip := context.PeerID.IP.To4()
	if ip == nil {
		util.Log(0, "ERROR! Cannot convert sender address to IPv4 address: %v", context.PeerID.IP)
	} else {
		go tryToReestablishCommunicationWith(ip.String())
	}

	return ErrorReplyBuffer("Could not decrypt message"), true
}

//.........这里部分代码省略.........
			}
			if readbuf[0] != starttls[i] {
				if config.TLSRequired {
					util.Log(0, "ERROR! No STARTTLS from %v, but TLS is required", conn.RemoteAddr())
					util.WriteAll(conn, []byte(message.ErrorReply("STARTTLS is required to connect")))
					return
				}
				break
			}
			if readbuf[0] == '\n' {
				buf.Reset() // purge STARTTLS\n from buffer
				conn = tls.Server(conn, config.TLSServerConfig)
			}
		}
	}

	context := security.ContextFor(conn)
	if context == nil {
		return
	}

	for n != 0 {
		//util.Log(2, "DEBUG! Receiving from %v", conn.RemoteAddr())
		n, err = conn.Read(readbuf)

		if err != nil && err != io.EOF {
			util.Log(0, "ERROR! Read: %v", err)
		}
		if err == io.EOF {
			util.Log(2, "DEBUG! Connection closed by %v", conn.RemoteAddr())
		}
		if n == 0 && err == nil {
			util.Log(0, "ERROR! Read 0 bytes but no error reported")
		}

		// Find complete lines terminated by '\n' and process them.
		for start := 0; ; {
			eol := start
			for ; eol < n; eol++ {
				if readbuf[eol] == '\n' {
					break
				}
			}

			// no \n found, append to buf and continue reading
			if eol == n {
				buf.Write(readbuf[start:n])
				break
			}

			// append to rest of line to buffered contents
			buf.Write(readbuf[start:eol])
			start = eol + 1

			buf.TrimSpace()

			// process the message and get a reply (if applicable)
			if buf.Len() > 0 { // ignore empty lines
				request_start := time.Now()
				reply, disconnect := message.ProcessEncryptedMessage(&buf, context)
				buf.Reset()
				request_time := time.Since(request_start)
				RequestProcessingTimes.Push(request_time)
				request_time -= RequestProcessingTimes.Next().(time.Duration)
				atomic.AddInt64(&message.RequestProcessingTime, int64(request_time))

				if reply.Len() > 0 {
					util.Log(2, "DEBUG! Sending %v bytes reply to %v", reply.Len(), conn.RemoteAddr())

					var deadline time.Time // zero value means "no deadline"
					if config.Timeout >= 0 {
						deadline = time.Now().Add(config.Timeout)
					}
					conn.SetWriteDeadline(deadline)

					_, err := util.WriteAll(conn, reply.Bytes())
					if err != nil {
						util.Log(0, "ERROR! WriteAll: %v", err)
					}
					reply.Reset()
					util.WriteAll(conn, []byte{'\r', '\n'})
				}

				if disconnect {
					util.Log(1, "INFO! Forcing disconnect of %v because of error", conn.RemoteAddr())
					return
				}

				if Shutdown {
					util.Log(1, "INFO! Forcing disconnect of %v because of go-susi shutdown", conn.RemoteAddr())
					return
				}
			}
		}
	}

	if buf.Len() != 0 {
		util.Log(0, "ERROR! Incomplete message from %v (i.e. not terminated by \"\\n\") of %v bytes: %v", conn.RemoteAddr(), buf.Len(), buf.String())
	}
}