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utils.go
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utils.go
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/*
Copyright 2015 Gravitational, Inc.
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 utils
import (
"io"
"io/ioutil"
"net"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"github.com/gravitational/teleport"
"github.com/gravitational/teleport/lib/modules"
"github.com/gravitational/trace"
"github.com/pborman/uuid"
)
// ParseAdvertiseAddress validates advertise address,
// makes sure it's not an unreachable or multicast address
// returns address split into host and port, port could be empty
// if not specified
func ParseAdvertiseAddr(advertiseIP string) (string, string, error) {
advertiseIP = strings.TrimSpace(advertiseIP)
host := advertiseIP
port := ""
if len(net.ParseIP(host)) == 0 && strings.Contains(advertiseIP, ":") {
var err error
host, port, err = net.SplitHostPort(advertiseIP)
if err != nil {
return "", "", trace.BadParameter("failed to parse address %q", advertiseIP)
}
if _, err := strconv.Atoi(port); err != nil {
return "", "", trace.BadParameter("bad port %q, expected integer", port)
}
if host == "" {
return "", "", trace.BadParameter("missing host parameter")
}
}
ip := net.ParseIP(host)
if len(ip) != 0 {
if ip.IsLoopback() || ip.IsUnspecified() || ip.IsMulticast() {
return "", "", trace.BadParameter("unreachable advertise IP: %v", advertiseIP)
}
}
return host, port, nil
}
// StringsSet creates set of string (map[string]struct{})
// from a list of strings
func StringsSet(in []string) map[string]struct{} {
if in == nil {
return nil
}
out := make(map[string]struct{})
for _, v := range in {
out[v] = struct{}{}
}
return out
}
// ParseOnOff parses whether value is "on" or "off", parameterName is passed for error
// reporting purposes, defaultValue is returned when no value is set
func ParseOnOff(parameterName, val string, defaultValue bool) (bool, error) {
switch val {
case teleport.On:
return true, nil
case teleport.Off:
return false, nil
case "":
return defaultValue, nil
default:
return false, trace.BadParameter("bad %q parameter value: %q, supported values are on or off", parameterName, val)
}
}
// IsGroupMember returns whether currently logged user is a member of a group
func IsGroupMember(gid int) (bool, error) {
groups, err := os.Getgroups()
if err != nil {
return false, trace.ConvertSystemError(err)
}
for _, group := range groups {
if group == gid {
return true, nil
}
}
return false, nil
}
// Host extracts host from host:port string
func Host(hostname string) (string, error) {
if hostname == "" {
return "", trace.BadParameter("missing parameter hostname")
}
if !strings.Contains(hostname, ":") {
return hostname, nil
}
host, _, err := SplitHostPort(hostname)
return host, err
}
// SplitHostPort splits host and port and checks that host is not empty
func SplitHostPort(hostname string) (string, string, error) {
host, port, err := net.SplitHostPort(hostname)
if err != nil {
return "", "", trace.Wrap(err)
}
if host == "" {
return "", "", trace.BadParameter("empty hostname")
}
return host, port, nil
}
func ReadPath(path string) ([]byte, error) {
s, err := filepath.Abs(path)
if err != nil {
return nil, trace.ConvertSystemError(err)
}
abs, err := filepath.EvalSymlinks(s)
if err != nil {
return nil, trace.ConvertSystemError(err)
}
bytes, err := ioutil.ReadFile(abs)
if err != nil {
return nil, trace.ConvertSystemError(err)
}
return bytes, nil
}
type multiCloser struct {
closers []io.Closer
}
func (mc *multiCloser) Close() error {
for _, closer := range mc.closers {
if err := closer.Close(); err != nil {
return trace.Wrap(err)
}
}
return nil
}
// MultiCloser implements io.Close, it sequentially calls Close() on each object
func MultiCloser(closers ...io.Closer) *multiCloser {
return &multiCloser{
closers: closers,
}
}
// IsHandshakeFailedError specifies whether this error indicates
// failed handshake
func IsHandshakeFailedError(err error) bool {
return strings.Contains(trace.Unwrap(err).Error(), "ssh: handshake failed")
}
// IsShellFailedError specifies whether this error indicates
// failed attempt to start shell
func IsShellFailedError(err error) bool {
return strings.Contains(err.Error(), "ssh: cound not start shell")
}
// PortList is a list of TCP port
type PortList []string
// Pop returns a value from the list, it panics if the value is not there
func (p *PortList) Pop() string {
if len(*p) == 0 {
panic("list is empty")
}
val := (*p)[len(*p)-1]
*p = (*p)[:len(*p)-1]
return val
}
// GetFreeTCPPorts returns n ports starting from port 20000.
func GetFreeTCPPorts(n int) (PortList, error) {
list := make(PortList, 0, n)
for i := 20000; i < 20000+n; i++ {
list = append(list, strconv.Itoa(i))
}
return list, nil
}
// ReadHostUUID reads host UUID from the file in the data dir
func ReadHostUUID(dataDir string) (string, error) {
out, err := ReadPath(filepath.Join(dataDir, HostUUIDFile))
if err != nil {
return "", trace.Wrap(err)
}
return strings.TrimSpace(string(out)), nil
}
// WriteHostUUID writes host UUID into a file
func WriteHostUUID(dataDir string, id string) error {
err := ioutil.WriteFile(filepath.Join(dataDir, HostUUIDFile), []byte(id), os.ModeExclusive|0400)
if err != nil {
return trace.ConvertSystemError(err)
}
return nil
}
// ReadOrMakeHostUUID looks for a hostid file in the data dir. If present,
// returns the UUID from it, otherwise generates one
func ReadOrMakeHostUUID(dataDir string) (string, error) {
id, err := ReadHostUUID(dataDir)
if err == nil {
return id, nil
}
if !trace.IsNotFound(err) {
return "", trace.Wrap(err)
}
id = uuid.New()
if err = WriteHostUUID(dataDir, id); err != nil {
return "", trace.Wrap(err)
}
return id, nil
}
// PrintVersion prints human readable version
func PrintVersion() {
modules.GetModules().PrintVersion()
}
// HumanTimeFormat formats time as recognized by humans
func HumanTimeFormat(d time.Time) string {
return d.Format(HumanTimeFormatString)
}
// Deduplicate deduplicates list of strings
func Deduplicate(in []string) []string {
if len(in) == 0 {
return in
}
out := make([]string, 0, len(in))
seen := make(map[string]bool, len(in))
for _, val := range in {
if _, ok := seen[val]; !ok {
out = append(out, val)
seen[val] = true
}
}
return out
}
// SliceContainsStr returns 'true' if the slice contains the given value
func SliceContainsStr(slice []string, value string) bool {
for i := range slice {
if slice[i] == value {
return true
}
}
return false
}
// RemoveFromSlice makes a copy of the slice and removes the passed in values from the copy.
func RemoveFromSlice(slice []string, values ...string) []string {
output := make([]string, 0, len(slice))
remove := make(map[string]bool)
for _, value := range values {
remove[value] = true
}
for _, s := range slice {
_, ok := remove[s]
if ok {
continue
}
output = append(output, s)
}
return output
}
// CheckCertificateFormatFlag checks if the certificate format is valid.
func CheckCertificateFormatFlag(s string) (string, error) {
switch s {
case teleport.CertificateFormatStandard, teleport.CertificateFormatOldSSH, teleport.CertificateFormatUnspecified:
return s, nil
default:
return "", trace.BadParameter("invalid certificate format parameter: %q", s)
}
}
const (
// HumanTimeFormatString is a human readable date formatting
HumanTimeFormatString = "Mon Jan _2 15:04 UTC"
// CertTeleportUser specifies teleport user
CertTeleportUser = "x-teleport-user"
// CertTeleportUserCA specifies teleport certificate authority
CertTeleportUserCA = "x-teleport-user-ca"
// CertExtensionRole specifies teleport role
CertExtensionRole = "x-teleport-role"
// CertExtensionAuthority specifies teleport authority's name
// that signed this domain
CertExtensionAuthority = "x-teleport-authority"
// HostUUIDFile is the file name where the host UUID file is stored
HostUUIDFile = "host_uuid"
// CertTeleportClusterName is a name of the teleport cluster
CertTeleportClusterName = "x-teleport-cluster-name"
// CertTeleportUserCertificate is the certificate of the authenticated in user.
CertTeleportUserCertificate = "x-teleport-certificate"
)