app: handle launch method in New function

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

flag.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"flag"
-
-	"git.ophivana.moe/cat/fortify/internal/app"
 )
 
 var (
@@ -38,9 +36,6 @@ func init() {
 	flag.BoolVar(&mustDBus, "dbus", false, "Proxy D-Bus connection")
 	flag.BoolVar(&mustPulse, "pulse", false, "Share PulseAudio socket and cookie")
 
-	flag.BoolVar(&app.LaunchOptions[app.LaunchMethodSudo], "sudo", false, "Use 'sudo' to switch user")
-	flag.BoolVar(&app.LaunchOptions[app.LaunchMethodMachineCtl], "machinectl", true, "Use 'machinectl' to switch user")
-
 	flag.BoolVar(&flagVerbose, "v", false, "Verbose output")
 	flag.BoolVar(&printVersion, "V", false, "Print version")
 }

internal/app/run.go

@@ -17,15 +17,9 @@ const (
 	sudoAskPass = "SUDO_ASKPASS"
 )
 const (
-	LaunchMethodSudo = iota
+	LaunchMethodSudo uint8 = iota
+	LaunchMethodBwrap
 	LaunchMethodMachineCtl
-
-	launchOptionLength
-)
-
-var (
-	// LaunchOptions is set in main's cli.go
-	LaunchOptions [launchOptionLength]bool
 )
 
 func (a *App) Run() {
@@ -34,34 +28,20 @@ func (a *App) Run() {
 		a.AppendEnv(term, t)
 	}
 
-	commandBuilder := a.commandBuilderSudo
+	var commandBuilder func() (args []string)
 
-	var toolPath string
-
-	// dependency checks
-	const sudoFallback = "Falling back to 'sudo', some desktop integration features may not work"
-	if LaunchOptions[LaunchMethodMachineCtl] && !LaunchOptions[LaunchMethodSudo] { // sudo argument takes priority
-		if !util.SdBooted() {
-			fmt.Println("This system was not booted through systemd")
-			fmt.Println(sudoFallback)
-		} else if machineCtlPath, ok := util.Which("machinectl"); !ok {
-			fmt.Println("Did not find 'machinectl' in PATH")
-			fmt.Println(sudoFallback)
-		} else {
-			toolPath = machineCtlPath
-			commandBuilder = a.commandBuilderMachineCtl
-		}
-	} else if sudoPath, ok := util.Which("sudo"); !ok {
-		state.Fatal("Did not find 'sudo' in PATH")
-	} else {
-		toolPath = sudoPath
+	switch a.launchOption {
+	case LaunchMethodSudo:
+		commandBuilder = a.commandBuilderSudo
+	case LaunchMethodBwrap:
+		commandBuilder = a.commandBuilderBwrap
+	case LaunchMethodMachineCtl:
+		commandBuilder = a.commandBuilderMachineCtl
+	default:
+		panic("unreachable")
 	}
 
-	if system.V.Verbose {
-		fmt.Printf("Selected launcher '%s'\n", toolPath)
-	}
-
-	cmd := exec.Command(toolPath, commandBuilder()...)
+	cmd := exec.Command(a.toolPath, commandBuilder()...)
 	cmd.Env = []string{}
 	cmd.Stdin = os.Stdin
 	cmd.Stdout = os.Stdout
@@ -122,6 +102,12 @@ func (a *App) commandBuilderSudo() (args []string) {
 	return
 }
 
+func (a *App) commandBuilderBwrap() (args []string) {
+	// TODO: build bwrap command
+	state.Fatal("bwrap")
+	panic("unreachable")
+}
+
 func (a *App) commandBuilderMachineCtl() (args []string) {
 	args = make([]string, 0, 9+len(a.env))
 

internal/app/setup.go

@@ -9,13 +9,19 @@ import (
 
 	"git.ophivana.moe/cat/fortify/internal/state"
 	"git.ophivana.moe/cat/fortify/internal/system"
+	"git.ophivana.moe/cat/fortify/internal/util"
 )
 
 type App struct {
+	launchOptionText string
+
 	uid     int
 	env     []string
 	command []string
 
+	launchOption uint8
+	toolPath     string
+
 	enablements state.Enablements
 	*user.User
 
@@ -23,6 +29,10 @@ type App struct {
 	// so don't treat it as if it is
 }
 
+func (a *App) LaunchOption() uint8 {
+	return a.launchOption
+}
+
 func (a *App) setEnablement(e state.Enablement) {
 	if a.enablements.Has(e) {
 		panic("enablement " + e.String() + " set twice")
@@ -31,8 +41,8 @@ func (a *App) setEnablement(e state.Enablement) {
 	a.enablements |= e.Mask()
 }
 
-func New(userName string, args []string) *App {
-	a := &App{command: args}
+func New(userName string, args []string, launchOptionText string) *App {
+	a := &App{command: args, launchOptionText: launchOptionText}
 
 	if u, err := user.Lookup(userName); err != nil {
 		if errors.As(err, new(user.UnknownUserError)) {
@@ -57,6 +67,47 @@ func New(userName string, args []string) *App {
 
 	if system.V.Verbose {
 		fmt.Println("Running as user", a.Username, "("+a.Uid+"),", "command:", a.command)
+		if util.SdBootedV {
+			fmt.Println("System booted with systemd as init system (PID 1).")
+		}
+	}
+
+	switch a.launchOptionText {
+	case "sudo":
+		a.launchOption = LaunchMethodSudo
+		if sudoPath, ok := util.Which("sudo"); !ok {
+			fmt.Println("Did not find 'sudo' in PATH")
+			os.Exit(1)
+		} else {
+			a.toolPath = sudoPath
+		}
+	case "bubblewrap":
+		a.launchOption = LaunchMethodBwrap
+		if bwrapPath, ok := util.Which("bwrap"); !ok {
+			fmt.Println("Did not find 'bwrap' in PATH")
+			os.Exit(1)
+		} else {
+			a.toolPath = bwrapPath
+		}
+	case "systemd":
+		a.launchOption = LaunchMethodMachineCtl
+		if !util.SdBootedV {
+			fmt.Println("System has not been booted with systemd as init system (PID 1).")
+			os.Exit(1)
+		}
+
+		if machineCtlPath, ok := util.Which("machinectl"); !ok {
+			fmt.Println("Did not find 'machinectl' in PATH")
+		} else {
+			a.toolPath = machineCtlPath
+		}
+	default:
+		fmt.Println("invalid launch method")
+		os.Exit(1)
+	}
+
+	if system.V.Verbose {
+		fmt.Println("Determined launch method to be", a.launchOptionText, "with tool at", a.toolPath)
 	}
 
 	return a

internal/util/early.go

@@ -0,0 +1,12 @@
+package util
+
+import "fmt"
+
+var SdBootedV = func() bool {
+	if v, err := SdBooted(); err != nil {
+		fmt.Println("warn: read systemd marker:", err)
+		return false
+	} else {
+		return v
+	}
+}()

internal/util/std.go

@@ -8,7 +8,6 @@ import (
 	"path"
 
 	"git.ophivana.moe/cat/fortify/internal/state"
-	"git.ophivana.moe/cat/fortify/internal/system"
 )
 
 const (
@@ -22,19 +21,16 @@ const (
 )
 
 // SdBooted implements https://www.freedesktop.org/software/systemd/man/sd_booted.html
-func SdBooted() bool {
+func SdBooted() (bool, error) {
 	_, err := os.Stat(systemdCheckPath)
 	if err != nil {
-		if system.V.Verbose {
-			if errors.Is(err, fs.ErrNotExist) {
-				fmt.Println("System not booted through systemd")
-			} else {
-				fmt.Println("Error accessing", systemdCheckPath+":", err.Error())
-			}
+		if errors.Is(err, fs.ErrNotExist) {
+			err = nil
 		}
-		return false
+		return false, err
 	}
-	return true
+
+	return true, nil
 }
 
 // DiscoverPulseCookie try various standard methods to discover the current user's PulseAudio authentication cookie

main.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
+	"path"
 	"strconv"
 	"syscall"
 
@@ -15,6 +16,7 @@ import (
 	"git.ophivana.moe/cat/fortify/internal/app"
 	"git.ophivana.moe/cat/fortify/internal/state"
 	"git.ophivana.moe/cat/fortify/internal/system"
+	"git.ophivana.moe/cat/fortify/internal/util"
 )
 
 var (
@@ -24,8 +26,19 @@ var (
 
 	dbusSession *dbus.Config
 	dbusSystem  *dbus.Config
+
+	launchOptionText string
 )
 
+func init() {
+	methodHelpString := "Method of launching the child process, can be one of \"sudo\", \"bubblewrap\""
+	if util.SdBootedV {
+		methodHelpString += ", \"systemd\""
+	}
+
+	flag.StringVar(&launchOptionText, "method", "sudo", methodHelpString)
+}
+
 func tryVersion() {
 	if printVersion {
 		fmt.Println(Version)
@@ -44,7 +57,7 @@ func main() {
 	tryLicense()
 
 	system.Retrieve(flagVerbose)
-	a = app.New(userName, flag.Args())
+	a = app.New(userName, flag.Args(), launchOptionText)
 	state.Set(*a.User, a.Command(), a.UID())
 
 	// parse D-Bus config file if applicable
@@ -87,6 +100,26 @@ func main() {
 		state.Fatal("Error creating shared directory:", err)
 	}
 
+	if a.LaunchOption() == app.LaunchMethodSudo {
+		// ensure child runtime directory (e.g. `/tmp/fortify.%d/%d.share`)
+		cr := path.Join(system.V.Share, a.Uid+".share")
+		if err := os.Mkdir(cr, 0700); err != nil && !errors.Is(err, fs.ErrExist) {
+			state.Fatal("Error creating child runtime directory:", err)
+		} else {
+			if err = acl.UpdatePerm(cr, a.UID(), acl.Read, acl.Write, acl.Execute); err != nil {
+				state.Fatal("Error preparing child runtime directory:", err)
+			} else {
+				state.RegisterRevertPath(cr)
+			}
+			a.AppendEnv("XDG_RUNTIME_DIR", cr)
+			a.AppendEnv("XDG_SESSION_CLASS", "user")
+			a.AppendEnv("XDG_SESSION_TYPE", "tty")
+			if system.V.Verbose {
+				fmt.Printf("Child runtime data dir '%s' configured\n", cr)
+			}
+		}
+	}
+
 	// warn about target user home directory ownership
 	if stat, err := os.Stat(a.HomeDir); err != nil {
 		if system.V.Verbose {
@@ -117,7 +150,7 @@ func main() {
 		state.Fatal(fmt.Sprintf("Path '%s' is not a directory", system.V.Runtime))
 	} else {
 		if err = acl.UpdatePerm(system.V.Runtime, a.UID(), acl.Execute); err != nil {
-			state.Fatal("Error preparing runtime dir:", err)
+			state.Fatal("Error preparing runtime directory:", err)
 		} else {
 			state.RegisterRevertPath(system.V.Runtime)
 		}