Consolidate init-system detection into shared inits package

Author: cicku

cmd/cloudflared/inits/inits.go

@@ -0,0 +1,39 @@
+// Package inits provides detection of the init system managing the host
+// (systemd, OpenRC, or SysV). It is shared by the service installer and the
+// auto-updater so that init-system detection lives in a single place.
+//
+// The functions are safe to call on any GOOS; on non-Linux platforms they
+// report that no Linux init system is in use.
+package inits
+
+import (
+	"os"
+	"runtime"
+)
+
+// IsSystemd reports whether the host is managed by systemd.
+func IsSystemd() bool {
+	_, err := os.Stat("/run/systemd/system")
+	return err == nil
+}
+
+// IsOpenRC reports whether the host is managed by OpenRC.
+func IsOpenRC() bool {
+	for _, path := range []string{"/sbin/openrc-run", "/usr/sbin/openrc-run", "/usr/bin/openrc-run"} {
+		if _, err := os.Stat(path); err == nil {
+			return true
+		}
+	}
+	return false
+}
+
+// IsSysV reports whether the host relies on a SysV-style init system, i.e. a
+// Linux host that is managed by neither systemd nor OpenRC. systemd and OpenRC
+// keep the service alive themselves, so only SysV needs the process to restart
+// itself after an auto-update.
+func IsSysV() bool {
+	if runtime.GOOS != "linux" {
+		return false
+	}
+	return !IsSystemd() && !IsOpenRC()
+}

cmd/cloudflared/linux_service.go

@@ -12,8 +12,8 @@ import (
 	"github.com/urfave/cli/v2"
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
+	"github.com/cloudflare/cloudflared/cmd/cloudflared/inits"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/tunnel"
-	"github.com/cloudflare/cloudflared/cmd/cloudflared/updater"
 	"github.com/cloudflare/cloudflared/config"
 	"github.com/cloudflare/cloudflared/logger"
 )
@@ -235,11 +235,6 @@ var noUpdateServiceFlag = &cli.BoolFlag{
 	Value: false,
 }
 
-func isSystemd() bool {
-	_, err := os.Stat("/run/systemd/system")
-	return err == nil
-}
-
 func installLinuxService(c *cli.Context) error {
 	log := logger.CreateLoggerFromContext(c, logger.EnableTerminalLog)
 
@@ -269,10 +264,10 @@ func installLinuxService(c *cli.Context) error {
 	templateArgs.ExtraArgs = extraArgs
 
 	switch {
-	case isSystemd():
+	case inits.IsSystemd():
 		log.Info().Msgf("Using Systemd")
 		err = installSystemd(&templateArgs, autoUpdate, log)
-	case updater.IsOpenRC():
+	case inits.IsOpenRC():
 		log.Info().Msgf("Using OpenRC")
 		err = installOpenRC(&templateArgs, autoUpdate)
 	default:
@@ -417,10 +412,10 @@ func uninstallLinuxService(c *cli.Context) error {
 
 	var err error
 	switch {
-	case isSystemd():
+	case inits.IsSystemd():
 		log.Info().Msg("Using Systemd")
 		err = uninstallSystemd(log)
-	case updater.IsOpenRC():
+	case inits.IsOpenRC():
 		log.Info().Msg("Using OpenRC")
 		err = uninstallOpenRC(log)
 	default:

cmd/cloudflared/updater/update.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
 	cfdflags "github.com/cloudflare/cloudflared/cmd/cloudflared/flags"
+	"github.com/cloudflare/cloudflared/cmd/cloudflared/inits"
 	"github.com/cloudflare/cloudflared/config"
 	"github.com/cloudflare/cloudflared/logger"
 )
@@ -248,7 +249,7 @@ func (a *AutoUpdater) Run(ctx context.Context) error {
 		updateOutcome := loggedUpdate(a.log, updateOptions{updateDisabled: !a.configurable.enabled})
 		if updateOutcome.Updated {
 			buildInfo.CloudflaredVersion = updateOutcome.Version
-			if IsSysV() {
+			if inits.IsSysV() {
 				// SysV doesn't have a mechanism to keep service alive, we have to restart the process
 				a.log.Info().Msg("Restarting service managed by SysV...")
 				pid, err := a.listeners.StartProcess()
@@ -300,27 +301,3 @@ func wasInstalledFromPackageManager() bool {
 func isRunningFromTerminal() bool {
 	return term.IsTerminal(int(os.Stdout.Fd()))
 }
-
-func IsSysV() bool {
-	if runtime.GOOS != "linux" {
-		return false
-	}
-
-	// systemd and OpenRC keep the service alive, so let them restart it.
-	if _, err := os.Stat("/run/systemd/system"); err == nil {
-		return false
-	}
-	if IsOpenRC() {
-		return false
-	}
-	return true
-}
-
-func IsOpenRC() bool {
-	for _, path := range []string{"/sbin/openrc-run", "/usr/sbin/openrc-run", "/usr/bin/openrc-run"} {
-		if _, err := os.Stat(path); err == nil {
-			return true
-		}
-	}
-	return false
-}