cmd/fpkg: app bundle helper

This helper program creates fortify configuration for running an application bundle. The activate action wraps a home-manager activation package and ensures each generation gets activated once.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/fpkg/start.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"flag"
+	"path"
+
+	"git.gensokyo.uk/security/fortify/fst"
+	"git.gensokyo.uk/security/fortify/internal/fmsg"
+)
+
+func actionStart(args []string) {
+	set := flag.NewFlagSet("start", flag.ExitOnError)
+	var dropShell bool
+	set.BoolVar(&dropShell, "s", false, "Drop to a shell on activation")
+
+	// Ignore errors; set is set for ExitOnError.
+	_ = set.Parse(args)
+
+	args = set.Args()
+
+	if len(args) < 1 {
+		fmsg.Fatal("invalid argument")
+	}
+	id := args[0]
+	pathSet := pathSetByApp(id)
+	app := loadBundleInfo(pathSet.metaPath, func() {})
+
+	if app.ID != id {
+		fmsg.Fatalf("app %q claims to have identifier %q", id, app.ID)
+	}
+
+	command := make([]string, 1, len(args))
+	if !dropShell {
+		command[0] = app.Launcher
+	} else {
+		command[0] = shell
+	}
+	command = append(command, args[1:]...)
+
+	config := &fst.Config{
+		ID:      app.ID,
+		Command: command,
+		Confinement: fst.ConfinementConfig{
+			AppID:    app.AppID,
+			Groups:   app.Groups,
+			Username: "fortify",
+			Inner:    path.Join("/data/data", app.ID),
+			Outer:    pathSet.homeDir,
+			Sandbox: &fst.SandboxConfig{
+				Hostname:      formatHostname(app.Name),
+				UserNS:        app.UserNS,
+				Net:           app.Net,
+				Dev:           app.Dev,
+				NoNewSession:  app.NoNewSession || dropShell,
+				MapRealUID:    app.MapRealUID,
+				DirectWayland: app.DirectWayland,
+				Filesystem: []*fst.FilesystemConfig{
+					{Src: path.Join(pathSet.nixPath, "store"), Dst: "/nix/store", Must: true},
+					{Src: pathSet.metaPath, Dst: path.Join(fst.Tmp, "app"), Must: true},
+					{Src: "/etc/resolv.conf"},
+					{Src: "/sys/block"},
+					{Src: "/sys/bus"},
+					{Src: "/sys/class"},
+					{Src: "/sys/dev"},
+					{Src: "/sys/devices"},
+				},
+				Link: [][2]string{
+					{app.CurrentSystem, "/run/current-system"},
+					{"/run/current-system/sw/bin", "/bin"},
+					{"/run/current-system/sw/bin", "/usr/bin"},
+				},
+				Etc:     path.Join(pathSet.cacheDir, "etc"),
+				AutoEtc: true,
+			},
+			ExtraPerms: []*fst.ExtraPermConfig{
+				{Path: dataHome, Execute: true},
+				{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
+			},
+			SystemBus:   app.SystemBus,
+			SessionBus:  app.SessionBus,
+			Enablements: app.Enablements,
+		},
+	}
+
+	if app.GPU {
+		config.Confinement.Sandbox.Filesystem = append(config.Confinement.Sandbox.Filesystem,
+			&fst.FilesystemConfig{Src: "/dev/dri", Device: true})
+	}
+
+	fortifyApp(config, func() {})
+	fmsg.Exit(0)
+}