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tailscale/hostinfo/hostinfo.go

448 lines
10 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package hostinfo answers questions about the host environment that Tailscale is
// running on.
package hostinfo
import (
"bufio"
"bytes"
"io"
"os"
"os/exec"
"runtime"
"runtime/debug"
"strings"
"sync"
"sync/atomic"
"time"
"go4.org/mem"
"tailscale.com/envknob"
"tailscale.com/tailcfg"
"tailscale.com/types/opt"
"tailscale.com/types/ptr"
"tailscale.com/util/cloudenv"
"tailscale.com/util/dnsname"
"tailscale.com/util/lineread"
"tailscale.com/version"
)
var started = time.Now()
// New returns a partially populated Hostinfo for the current host.
func New() *tailcfg.Hostinfo {
hostname, _ := os.Hostname()
hostname = dnsname.FirstLabel(hostname)
return &tailcfg.Hostinfo{
IPNVersion: version.Long(),
Hostname: hostname,
App: appTypeCached(),
OS: version.OS(),
OSVersion: GetOSVersion(),
Container: lazyInContainer.Get(),
Distro: condCall(distroName),
DistroVersion: condCall(distroVersion),
DistroCodeName: condCall(distroCodeName),
Env: string(GetEnvType()),
Desktop: desktop(),
Package: packageTypeCached(),
GoArch: runtime.GOARCH,
GoArchVar: lazyGoArchVar.Get(),
GoVersion: runtime.Version(),
Machine: condCall(unameMachine),
DeviceModel: deviceModel(),
PushDeviceToken: pushDeviceToken(),
Cloud: string(cloudenv.Get()),
NoLogsNoSupport: envknob.NoLogsNoSupport(),
AllowsUpdate: envknob.AllowsRemoteUpdate(),
}
}
// non-nil on some platforms
var (
osVersion func() string
packageType func() string
distroName func() string
distroVersion func() string
distroCodeName func() string
unameMachine func() string
)
func condCall[T any](fn func() T) T {
var zero T
if fn == nil {
return zero
}
return fn()
}
var (
lazyInContainer = &lazyAtomicValue[opt.Bool]{f: ptr.To(inContainer)}
lazyGoArchVar = &lazyAtomicValue[string]{f: ptr.To(goArchVar)}
)
type lazyAtomicValue[T any] struct {
// f is a pointer to a fill function. If it's nil or points
// to nil, then Get returns the zero value for T.
f *func() T
once sync.Once
v T
}
func (v *lazyAtomicValue[T]) Get() T {
v.once.Do(v.fill)
return v.v
}
func (v *lazyAtomicValue[T]) fill() {
if v.f == nil || *v.f == nil {
return
}
v.v = (*v.f)()
}
// GetOSVersion returns the OSVersion of current host if available.
func GetOSVersion() string {
if s, _ := osVersionAtomic.Load().(string); s != "" {
return s
}
if osVersion != nil {
return osVersion()
}
return ""
}
func appTypeCached() string {
if v, ok := appType.Load().(string); ok {
return v
}
return ""
}
func packageTypeCached() string {
if v, _ := packagingType.Load().(string); v != "" {
return v
}
if packageType == nil {
return ""
}
v := packageType()
if v != "" {
SetPackage(v)
}
return v
}
// EnvType represents a known environment type.
// The empty string, the default, means unknown.
type EnvType string
const (
KNative = EnvType("kn")
AWSLambda = EnvType("lm")
Heroku = EnvType("hr")
AzureAppService = EnvType("az")
AWSFargate = EnvType("fg")
FlyDotIo = EnvType("fly")
Kubernetes = EnvType("k8s")
DockerDesktop = EnvType("dde")
Replit = EnvType("repl")
)
var envType atomic.Value // of EnvType
func GetEnvType() EnvType {
if e, ok := envType.Load().(EnvType); ok {
return e
}
e := getEnvType()
envType.Store(e)
return e
}
var (
pushDeviceTokenAtomic atomic.Value // of string
deviceModelAtomic atomic.Value // of string
osVersionAtomic atomic.Value // of string
desktopAtomic atomic.Value // of opt.Bool
packagingType atomic.Value // of string
appType atomic.Value // of string
)
// SetPushDeviceToken sets the device token for use in Hostinfo updates.
func SetPushDeviceToken(token string) { pushDeviceTokenAtomic.Store(token) }
// SetDeviceModel sets the device model for use in Hostinfo updates.
func SetDeviceModel(model string) { deviceModelAtomic.Store(model) }
// SetOSVersion sets the OS version.
func SetOSVersion(v string) { osVersionAtomic.Store(v) }
// SetPackage sets the packaging type for the app.
//
// As of 2022-03-25, this is used by Android ("nogoogle" for the
// F-Droid build) and tsnet (set to "tsnet").
func SetPackage(v string) { packagingType.Store(v) }
// SetApp sets the app type for the app.
// It is used by tsnet to specify what app is using it such as "golinks"
// and "k8s-operator".
func SetApp(v string) { appType.Store(v) }
func deviceModel() string {
s, _ := deviceModelAtomic.Load().(string)
return s
}
func pushDeviceToken() string {
s, _ := pushDeviceTokenAtomic.Load().(string)
return s
}
func desktop() (ret opt.Bool) {
if runtime.GOOS != "linux" {
return opt.Bool("")
}
if v := desktopAtomic.Load(); v != nil {
v, _ := v.(opt.Bool)
return v
}
seenDesktop := false
lineread.File("/proc/net/unix", func(line []byte) error {
seenDesktop = seenDesktop || mem.Contains(mem.B(line), mem.S(" @/tmp/dbus-"))
seenDesktop = seenDesktop || mem.Contains(mem.B(line), mem.S(".X11-unix"))
seenDesktop = seenDesktop || mem.Contains(mem.B(line), mem.S("/wayland-1"))
return nil
})
ret.Set(seenDesktop)
// Only cache after a minute - compositors might not have started yet.
if time.Since(started) > time.Minute {
desktopAtomic.Store(ret)
}
return ret
}
func getEnvType() EnvType {
if inKnative() {
return KNative
}
if inAWSLambda() {
return AWSLambda
}
if inHerokuDyno() {
return Heroku
}
if inAzureAppService() {
return AzureAppService
}
if inAWSFargate() {
return AWSFargate
}
if inFlyDotIo() {
return FlyDotIo
}
if inKubernetes() {
return Kubernetes
}
if inDockerDesktop() {
return DockerDesktop
}
if inReplit() {
return Replit
}
return ""
}
// inContainer reports whether we're running in a container.
func inContainer() opt.Bool {
if runtime.GOOS != "linux" {
return ""
}
var ret opt.Bool
ret.Set(false)
if _, err := os.Stat("/.dockerenv"); err == nil {
ret.Set(true)
return ret
}
if _, err := os.Stat("/run/.containerenv"); err == nil {
// See https://github.com/cri-o/cri-o/issues/5461
ret.Set(true)
return ret
}
lineread.File("/proc/1/cgroup", func(line []byte) error {
if mem.Contains(mem.B(line), mem.S("/docker/")) ||
mem.Contains(mem.B(line), mem.S("/lxc/")) {
ret.Set(true)
return io.EOF // arbitrary non-nil error to stop loop
}
return nil
})
lineread.File("/proc/mounts", func(line []byte) error {
if mem.Contains(mem.B(line), mem.S("fuse.lxcfs")) {
ret.Set(true)
return io.EOF
}
return nil
})
return ret
}
func inKnative() bool {
// https://cloud.google.com/run/docs/reference/container-contract#env-vars
if os.Getenv("K_REVISION") != "" && os.Getenv("K_CONFIGURATION") != "" &&
os.Getenv("K_SERVICE") != "" && os.Getenv("PORT") != "" {
return true
}
return false
}
func inAWSLambda() bool {
// https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html
if os.Getenv("AWS_LAMBDA_FUNCTION_NAME") != "" &&
os.Getenv("AWS_LAMBDA_FUNCTION_VERSION") != "" &&
os.Getenv("AWS_LAMBDA_INITIALIZATION_TYPE") != "" &&
os.Getenv("AWS_LAMBDA_RUNTIME_API") != "" {
return true
}
return false
}
func inHerokuDyno() bool {
// https://devcenter.heroku.com/articles/dynos#local-environment-variables
if os.Getenv("PORT") != "" && os.Getenv("DYNO") != "" {
return true
}
return false
}
func inAzureAppService() bool {
if os.Getenv("APPSVC_RUN_ZIP") != "" && os.Getenv("WEBSITE_STACK") != "" &&
os.Getenv("WEBSITE_AUTH_AUTO_AAD") != "" {
return true
}
return false
}
func inAWSFargate() bool {
if os.Getenv("AWS_EXECUTION_ENV") == "AWS_ECS_FARGATE" {
return true
}
return false
}
func inFlyDotIo() bool {
if os.Getenv("FLY_APP_NAME") != "" && os.Getenv("FLY_REGION") != "" {
return true
}
return false
}
func inReplit() bool {
// https://docs.replit.com/programming-ide/getting-repl-metadata
if os.Getenv("REPL_OWNER") != "" && os.Getenv("REPL_SLUG") != "" {
return true
}
return false
}
func inKubernetes() bool {
if os.Getenv("KUBERNETES_SERVICE_HOST") != "" && os.Getenv("KUBERNETES_SERVICE_PORT") != "" {
return true
}
return false
}
func inDockerDesktop() bool {
if os.Getenv("TS_HOST_ENV") == "dde" {
return true
}
return false
}
// goArchVar returns the GOARM or GOAMD64 etc value that the binary was built
// with.
func goArchVar() string {
bi, ok := debug.ReadBuildInfo()
if !ok {
return ""
}
// Look for GOARM, GOAMD64, GO386, etc. Note that the little-endian
// "le"-suffixed GOARCH values don't have their own environment variable.
//
// See https://pkg.go.dev/cmd/go#hdr-Environment_variables and the
// "Architecture-specific environment variables" section:
wantKey := "GO" + strings.ToUpper(strings.TrimSuffix(runtime.GOARCH, "le"))
for _, s := range bi.Settings {
if s.Key == wantKey {
return s.Value
}
}
return ""
}
type etcAptSrcResult struct {
mod time.Time
disabled bool
}
var etcAptSrcCache atomic.Value // of etcAptSrcResult
// DisabledEtcAptSource reports whether Ubuntu (or similar) has disabled
// the /etc/apt/sources.list.d/tailscale.list file contents upon upgrade
// to a new release of the distro.
//
// See https://github.com/tailscale/tailscale/issues/3177
func DisabledEtcAptSource() bool {
if runtime.GOOS != "linux" {
return false
}
const path = "/etc/apt/sources.list.d/tailscale.list"
fi, err := os.Stat(path)
if err != nil || !fi.Mode().IsRegular() {
return false
}
mod := fi.ModTime()
if c, ok := etcAptSrcCache.Load().(etcAptSrcResult); ok && c.mod.Equal(mod) {
return c.disabled
}
f, err := os.Open(path)
if err != nil {
return false
}
defer f.Close()
v := etcAptSourceFileIsDisabled(f)
etcAptSrcCache.Store(etcAptSrcResult{mod: mod, disabled: v})
return v
}
func etcAptSourceFileIsDisabled(r io.Reader) bool {
bs := bufio.NewScanner(r)
disabled := false // did we find the "disabled on upgrade" comment?
for bs.Scan() {
line := strings.TrimSpace(bs.Text())
if strings.Contains(line, "# disabled on upgrade") {
disabled = true
}
if line == "" || line[0] == '#' {
continue
}
// Well, it has some contents in it at least.
return false
}
return disabled
}
// IsSELinuxEnforcing reports whether SELinux is in "Enforcing" mode.
func IsSELinuxEnforcing() bool {
if runtime.GOOS != "linux" {
return false
}
out, _ := exec.Command("getenforce").Output()
return string(bytes.TrimSpace(out)) == "Enforcing"
}