cmd/hpkg: rename from planterette

Planterette is now developed in another repository, so rename this proof of concept to avoid confusion.

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

10 files changed, 1265 insertions, 0 deletions

diff --git a/cmd/hpkg/app.go b/cmd/hpkg/app.go
new file mode 100644
index 00000000..082bc28e
--- /dev/null
+++ b/cmd/hpkg/app.go
@@ -0,0 +1,154 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+	"path"
+
+	"hakurei.app/container/seccomp"
+	"hakurei.app/hst"
+	"hakurei.app/system"
+	"hakurei.app/system/dbus"
+)
+
+type appInfo struct {
+	Name    string `json:"name"`
+	Version string `json:"version"`
+
+	// passed through to [hst.Config]
+	ID string `json:"id"`
+	// passed through to [hst.Config]
+	Identity int `json:"identity"`
+	// passed through to [hst.Config]
+	Groups []string `json:"groups,omitempty"`
+	// passed through to [hst.Config]
+	Devel bool `json:"devel,omitempty"`
+	// passed through to [hst.Config]
+	Userns bool `json:"userns,omitempty"`
+	// passed through to [hst.Config]
+	Net bool `json:"net,omitempty"`
+	// passed through to [hst.Config]
+	Device bool `json:"dev,omitempty"`
+	// passed through to [hst.Config]
+	Tty bool `json:"tty,omitempty"`
+	// passed through to [hst.Config]
+	MapRealUID bool `json:"map_real_uid,omitempty"`
+	// passed through to [hst.Config]
+	DirectWayland bool `json:"direct_wayland,omitempty"`
+	// passed through to [hst.Config]
+	SystemBus *dbus.Config `json:"system_bus,omitempty"`
+	// passed through to [hst.Config]
+	SessionBus *dbus.Config `json:"session_bus,omitempty"`
+	// passed through to [hst.Config]
+	Enablements system.Enablement `json:"enablements"`
+
+	// passed through to [hst.Config]
+	Multiarch bool `json:"multiarch,omitempty"`
+	// passed through to [hst.Config]
+	Bluetooth bool `json:"bluetooth,omitempty"`
+
+	// allow gpu access within sandbox
+	GPU bool `json:"gpu"`
+	// store path to nixGL mesa wrappers
+	Mesa string `json:"mesa,omitempty"`
+	// store path to nixGL source
+	NixGL string `json:"nix_gl,omitempty"`
+	// store path to activate-and-exec script
+	Launcher string `json:"launcher"`
+	// store path to /run/current-system
+	CurrentSystem string `json:"current_system"`
+	// store path to home-manager activation package
+	ActivationPackage string `json:"activation_package"`
+}
+
+func (app *appInfo) toFst(pathSet *appPathSet, argv []string, flagDropShell bool) *hst.Config {
+	config := &hst.Config{
+		ID: app.ID,
+
+		Path: argv[0],
+		Args: argv,
+
+		Enablements: app.Enablements,
+
+		SystemBus:     app.SystemBus,
+		SessionBus:    app.SessionBus,
+		DirectWayland: app.DirectWayland,
+
+		Username: "hakurei",
+		Shell:    shellPath,
+		Data:     pathSet.homeDir,
+		Dir:      path.Join("/data/data", app.ID),
+
+		Identity: app.Identity,
+		Groups:   app.Groups,
+
+		Container: &hst.ContainerConfig{
+			Hostname:   formatHostname(app.Name),
+			Devel:      app.Devel,
+			Userns:     app.Userns,
+			Net:        app.Net,
+			Device:     app.Device,
+			Tty:        app.Tty || flagDropShell,
+			MapRealUID: app.MapRealUID,
+			Filesystem: []*hst.FilesystemConfig{
+				{Src: path.Join(pathSet.nixPath, "store"), Dst: "/nix/store", Must: true},
+				{Src: pathSet.metaPath, Dst: path.Join(hst.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: []*hst.ExtraPermConfig{
+			{Path: dataHome, Execute: true},
+			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
+		},
+	}
+	if app.Multiarch {
+		config.Container.SeccompFlags |= seccomp.AllowMultiarch
+	}
+	if app.Bluetooth {
+		config.Container.SeccompFlags |= seccomp.AllowBluetooth
+	}
+	return config
+}
+
+func loadAppInfo(name string, beforeFail func()) *appInfo {
+	bundle := new(appInfo)
+	if f, err := os.Open(name); err != nil {
+		beforeFail()
+		log.Fatalf("cannot open bundle: %v", err)
+	} else if err = json.NewDecoder(f).Decode(&bundle); err != nil {
+		beforeFail()
+		log.Fatalf("cannot parse bundle metadata: %v", err)
+	} else if err = f.Close(); err != nil {
+		log.Printf("cannot close bundle metadata: %v", err)
+		// not fatal
+	}
+
+	if bundle.ID == "" {
+		beforeFail()
+		log.Fatal("application identifier must not be empty")
+	}
+
+	return bundle
+}
+
+func formatHostname(name string) string {
+	if h, err := os.Hostname(); err != nil {
+		log.Printf("cannot get hostname: %v", err)
+		return "hakurei-" + name
+	} else {
+		return h + "-" + name
+	}
+}
diff --git a/cmd/hpkg/build.nix b/cmd/hpkg/build.nix
new file mode 100644
index 00000000..13f3144f
--- /dev/null
+++ b/cmd/hpkg/build.nix
@@ -0,0 +1,251 @@
+{
+  nixpkgsFor,
+  system,
+  nixpkgs,
+  home-manager,
+}:
+
+{
+  lib,
+  stdenv,
+  closureInfo,
+  writeScript,
+  runtimeShell,
+  writeText,
+  symlinkJoin,
+  vmTools,
+  runCommand,
+  fetchFromGitHub,
+
+  zstd,
+  nix,
+  sqlite,
+
+  name ? throw "name is required",
+  version ? throw "version is required",
+  pname ? "${name}-${version}",
+  modules ? [ ],
+  nixosModules ? [ ],
+  script ? ''
+    exec "$SHELL" "$@"
+  '',
+
+  id ? name,
+  identity ? throw "identity is required",
+  groups ? [ ],
+  userns ? false,
+  net ? true,
+  dev ? false,
+  no_new_session ? false,
+  map_real_uid ? false,
+  direct_wayland ? false,
+  system_bus ? null,
+  session_bus ? null,
+
+  allow_wayland ? true,
+  allow_x11 ? false,
+  allow_dbus ? true,
+  allow_pulse ? true,
+  gpu ? allow_wayland || allow_x11,
+}:
+
+let
+  inherit (lib) optionals;
+
+  homeManagerConfiguration = home-manager.lib.homeManagerConfiguration {
+    pkgs = nixpkgsFor.${system};
+    modules = modules ++ [
+      {
+        home = {
+          username = "hakurei";
+          homeDirectory = "/data/data/${id}";
+          stateVersion = "22.11";
+        };
+      }
+    ];
+  };
+
+  launcher = writeScript "hakurei-${pname}" ''
+    #!${runtimeShell} -el
+    ${script}
+  '';
+
+  extraNixOSConfig =
+    { pkgs, ... }:
+    {
+      environment = {
+        etc.nixpkgs.source = nixpkgs.outPath;
+        systemPackages = [ pkgs.nix ];
+      };
+
+      imports = nixosModules;
+    };
+  nixos = nixpkgs.lib.nixosSystem {
+    inherit system;
+    modules = [
+      extraNixOSConfig
+      { nix.settings.experimental-features = [ "flakes" ]; }
+      { nix.settings.experimental-features = [ "nix-command" ]; }
+      { boot.isContainer = true; }
+      { system.stateVersion = "22.11"; }
+    ];
+  };
+
+  etc = vmTools.runInLinuxVM (
+    runCommand "etc" { } ''
+      mkdir -p /etc
+      ${nixos.config.system.build.etcActivationCommands}
+
+      # remove unused files
+      rm -rf /etc/sudoers
+
+      mkdir -p $out
+      tar -C /etc -cf "$out/etc.tar" .
+    ''
+  );
+
+  extendSessionDefault = id: ext: {
+    filter = true;
+
+    talk = [ "org.freedesktop.Notifications" ] ++ ext.talk;
+    own =
+      (optionals (id != null) [
+        "${id}.*"
+        "org.mpris.MediaPlayer2.${id}.*"
+      ])
+      ++ ext.own;
+
+    inherit (ext) call broadcast;
+  };
+
+  nixGL = fetchFromGitHub {
+    owner = "nix-community";
+    repo = "nixGL";
+    rev = "310f8e49a149e4c9ea52f1adf70cdc768ec53f8a";
+    hash = "sha256-lnzZQYG0+EXl/6NkGpyIz+FEOc/DSEG57AP1VsdeNrM=";
+  };
+
+  mesaWrappers =
+    let
+      isIntelX86Platform = system == "x86_64-linux";
+      nixGLPackages = import (nixGL + "/default.nix") {
+        pkgs = nixpkgs.legacyPackages.${system};
+        enable32bits = isIntelX86Platform;
+        enableIntelX86Extensions = isIntelX86Platform;
+      };
+    in
+    symlinkJoin {
+      name = "nixGL-mesa";
+      paths = with nixGLPackages; [
+        nixGLIntel
+        nixVulkanIntel
+      ];
+    };
+
+  info = builtins.toJSON {
+    inherit
+      name
+      version
+      id
+      identity
+      launcher
+      groups
+      userns
+      net
+      dev
+      no_new_session
+      map_real_uid
+      direct_wayland
+      system_bus
+      gpu
+      ;
+
+    session_bus =
+      if session_bus != null then
+        (session_bus (extendSessionDefault id))
+      else
+        (extendSessionDefault id {
+          talk = [ ];
+          own = [ ];
+          call = { };
+          broadcast = { };
+        });
+
+    enablements = (if allow_wayland then 1 else 0) + (if allow_x11 then 2 else 0) + (if allow_dbus then 4 else 0) + (if allow_pulse then 8 else 0);
+
+    mesa = if gpu then mesaWrappers else null;
+    nix_gl = if gpu then nixGL else null;
+    current_system = nixos.config.system.build.toplevel;
+    activation_package = homeManagerConfiguration.activationPackage;
+  };
+in
+
+stdenv.mkDerivation {
+  name = "${pname}.pkg";
+  inherit version;
+  __structuredAttrs = true;
+
+  nativeBuildInputs = [
+    zstd
+    nix
+    sqlite
+  ];
+
+  buildCommand = ''
+    NIX_ROOT="$(mktemp -d)"
+    export USER="nobody"
+
+    # create bootstrap store
+    bootstrapClosureInfo="${
+      closureInfo {
+        rootPaths = [
+          nix
+          nixos.config.system.build.toplevel
+        ];
+      }
+    }"
+    echo "copying bootstrap store paths..."
+    mkdir -p "$NIX_ROOT/nix/store"
+    xargs -n 1 -a "$bootstrapClosureInfo/store-paths" cp -at "$NIX_ROOT/nix/store/"
+    NIX_REMOTE="local?root=$NIX_ROOT" nix-store --load-db < "$bootstrapClosureInfo/registration"
+    NIX_REMOTE="local?root=$NIX_ROOT" nix-store --optimise
+    sqlite3 "$NIX_ROOT/nix/var/nix/db/db.sqlite" "UPDATE ValidPaths SET registrationTime = ''${SOURCE_DATE_EPOCH}"
+    chmod -R +r "$NIX_ROOT/nix/var"
+
+    # create binary cache
+    closureInfo="${
+      closureInfo {
+        rootPaths = [
+          homeManagerConfiguration.activationPackage
+          launcher
+        ]
+        ++ optionals gpu [
+          mesaWrappers
+          nixGL
+        ];
+      }
+    }"
+    echo "copying application paths..."
+    TMP_STORE="$(mktemp -d)"
+    mkdir -p "$TMP_STORE/nix/store"
+    xargs -n 1 -a "$closureInfo/store-paths" cp -at "$TMP_STORE/nix/store/"
+    NIX_REMOTE="local?root=$TMP_STORE" nix-store --load-db < "$closureInfo/registration"
+    sqlite3 "$TMP_STORE/nix/var/nix/db/db.sqlite" "UPDATE ValidPaths SET registrationTime = ''${SOURCE_DATE_EPOCH}"
+    NIX_REMOTE="local?root=$TMP_STORE" nix --offline --extra-experimental-features nix-command \
+        --verbose --log-format raw-with-logs \
+        copy --all --no-check-sigs --to \
+        "file://$NIX_ROOT/res?compression=zstd&compression-level=19&parallel-compression=true"
+
+    # package /etc
+    mkdir -p "$NIX_ROOT/etc"
+    tar -C "$NIX_ROOT/etc" -xf "${etc}/etc.tar"
+
+    # write metadata
+    cp "${writeText "bundle.json" info}" "$NIX_ROOT/bundle.json"
+
+    # create an intermediate file to improve zstd performance
+    INTER="$(mktemp)"
+    tar -C "$NIX_ROOT" -cf "$INTER" .
+    zstd -T0 -19 -fo "$out" "$INTER"
+  '';
+}
diff --git a/cmd/hpkg/main.go b/cmd/hpkg/main.go
new file mode 100644
index 00000000..d808aa01
--- /dev/null
+++ b/cmd/hpkg/main.go
@@ -0,0 +1,333 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"log"
+	"os"
+	"os/signal"
+	"path"
+	"syscall"
+
+	"hakurei.app/command"
+	"hakurei.app/hst"
+	"hakurei.app/internal"
+	"hakurei.app/internal/hlog"
+)
+
+const shellPath = "/run/current-system/sw/bin/bash"
+
+var (
+	errSuccess = errors.New("success")
+)
+
+func init() {
+	hlog.Prepare("hpkg")
+	if err := os.Setenv("SHELL", shellPath); err != nil {
+		log.Fatalf("cannot set $SHELL: %v", err)
+	}
+}
+
+func main() {
+	if os.Geteuid() == 0 {
+		log.Fatal("this program must not run as root")
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(),
+		syscall.SIGINT, syscall.SIGTERM)
+	defer stop() // unreachable
+
+	var (
+		flagVerbose   bool
+		flagDropShell bool
+	)
+	c := command.New(os.Stderr, log.Printf, "hpkg", func([]string) error { internal.InstallOutput(flagVerbose); return nil }).
+		Flag(&flagVerbose, "v", command.BoolFlag(false), "Print debug messages to the console").
+		Flag(&flagDropShell, "s", command.BoolFlag(false), "Drop to a shell in place of next hakurei action")
+
+	{
+		var (
+			flagDropShellActivate bool
+		)
+		c.NewCommand("install", "Install an application from its package", func(args []string) error {
+			if len(args) != 1 {
+				log.Println("invalid argument")
+				return syscall.EINVAL
+			}
+			pkgPath := args[0]
+			if !path.IsAbs(pkgPath) {
+				if dir, err := os.Getwd(); err != nil {
+					log.Printf("cannot get current directory: %v", err)
+					return err
+				} else {
+					pkgPath = path.Join(dir, pkgPath)
+				}
+			}
+
+			/*
+				Look up paths to programs started by hpkg.
+				This is done here to ease error handling as cleanup is not yet required.
+			*/
+
+			var (
+				_     = lookPath("zstd")
+				tar   = lookPath("tar")
+				chmod = lookPath("chmod")
+				rm    = lookPath("rm")
+			)
+
+			/*
+				Extract package and set up for cleanup.
+			*/
+
+			var workDir string
+			if p, err := os.MkdirTemp("", "hpkg.*"); err != nil {
+				log.Printf("cannot create temporary directory: %v", err)
+				return err
+			} else {
+				workDir = p
+			}
+			cleanup := func() {
+				// should be faster than a native implementation
+				mustRun(chmod, "-R", "+w", workDir)
+				mustRun(rm, "-rf", workDir)
+			}
+			beforeRunFail.Store(&cleanup)
+
+			mustRun(tar, "-C", workDir, "-xf", pkgPath)
+
+			/*
+				Parse bundle and app metadata, do pre-install checks.
+			*/
+
+			bundle := loadAppInfo(path.Join(workDir, "bundle.json"), cleanup)
+			pathSet := pathSetByApp(bundle.ID)
+
+			a := bundle
+			if s, err := os.Stat(pathSet.metaPath); err != nil {
+				if !os.IsNotExist(err) {
+					cleanup()
+					log.Printf("cannot access %q: %v", pathSet.metaPath, err)
+					return err
+				}
+				// did not modify app, clean installation condition met later
+			} else if s.IsDir() {
+				cleanup()
+				log.Printf("metadata path %q is not a file", pathSet.metaPath)
+				return syscall.EBADMSG
+			} else {
+				a = loadAppInfo(pathSet.metaPath, cleanup)
+				if a.ID != bundle.ID {
+					cleanup()
+					log.Printf("app %q claims to have identifier %q",
+						bundle.ID, a.ID)
+					return syscall.EBADE
+				}
+				// sec: should verify credentials
+			}
+
+			if a != bundle {
+				// do not try to re-install
+				if a.NixGL == bundle.NixGL &&
+					a.CurrentSystem == bundle.CurrentSystem &&
+					a.Launcher == bundle.Launcher &&
+					a.ActivationPackage == bundle.ActivationPackage {
+					cleanup()
+					log.Printf("package %q is identical to local application %q",
+						pkgPath, a.ID)
+					return errSuccess
+				}
+
+				// identity determines uid
+				if a.Identity != bundle.Identity {
+					cleanup()
+					log.Printf("package %q identity %d differs from installed %d",
+						pkgPath, bundle.Identity, a.Identity)
+					return syscall.EBADE
+				}
+
+				// sec: should compare version string
+				hlog.Verbosef("installing application %q version %q over local %q",
+					bundle.ID, bundle.Version, a.Version)
+			} else {
+				hlog.Verbosef("application %q clean installation", bundle.ID)
+				// sec: should install credentials
+			}
+
+			/*
+				Setup steps for files owned by the target user.
+			*/
+
+			withCacheDir(ctx, "install", []string{
+				// export inner bundle path in the environment
+				"export BUNDLE=" + hst.Tmp + "/bundle",
+				// replace inner /etc
+				"mkdir -p etc",
+				"chmod -R +w etc",
+				"rm -rf etc",
+				"cp -dRf $BUNDLE/etc etc",
+				// replace inner /nix
+				"mkdir -p nix",
+				"chmod -R +w nix",
+				"rm -rf nix",
+				"cp -dRf /nix nix",
+				// copy from binary cache
+				"nix copy --offline --no-check-sigs --all --from file://$BUNDLE/res --to $PWD",
+				// deduplicate nix store
+				"nix store --offline --store $PWD optimise",
+				// make cache directory world-readable for autoetc
+				"chmod 0755 .",
+			}, workDir, bundle, pathSet, flagDropShell, cleanup)
+
+			if bundle.GPU {
+				withCacheDir(ctx, "mesa-wrappers", []string{
+					// link nixGL mesa wrappers
+					"mkdir -p nix/.nixGL",
+					"ln -s " + bundle.Mesa + "/bin/nixGLIntel nix/.nixGL/nixGL",
+					"ln -s " + bundle.Mesa + "/bin/nixVulkanIntel nix/.nixGL/nixVulkan",
+				}, workDir, bundle, pathSet, false, cleanup)
+			}
+
+			/*
+				Activate home-manager generation.
+			*/
+
+			withNixDaemon(ctx, "activate", []string{
+				// clean up broken links
+				"mkdir -p .local/state/{nix,home-manager}",
+				"chmod -R +w .local/state/{nix,home-manager}",
+				"rm -rf .local/state/{nix,home-manager}",
+				// run activation script
+				bundle.ActivationPackage + "/activate",
+			}, false, func(config *hst.Config) *hst.Config { return config },
+				bundle, pathSet, flagDropShellActivate, cleanup)
+
+			/*
+				Installation complete. Write metadata to block re-installs or downgrades.
+			*/
+
+			// serialise metadata to ensure consistency
+			if f, err := os.OpenFile(pathSet.metaPath+"~", os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644); err != nil {
+				cleanup()
+				log.Printf("cannot create metadata file: %v", err)
+				return err
+			} else if err = json.NewEncoder(f).Encode(bundle); err != nil {
+				cleanup()
+				log.Printf("cannot write metadata: %v", err)
+				return err
+			} else if err = f.Close(); err != nil {
+				log.Printf("cannot close metadata file: %v", err)
+				// not fatal
+			}
+
+			if err := os.Rename(pathSet.metaPath+"~", pathSet.metaPath); err != nil {
+				cleanup()
+				log.Printf("cannot rename metadata file: %v", err)
+				return err
+			}
+
+			cleanup()
+			return errSuccess
+		}).
+			Flag(&flagDropShellActivate, "s", command.BoolFlag(false), "Drop to a shell on activation")
+	}
+
+	{
+		var (
+			flagDropShellNixGL bool
+			flagAutoDrivers    bool
+		)
+		c.NewCommand("start", "Start an application", func(args []string) error {
+			if len(args) < 1 {
+				log.Println("invalid argument")
+				return syscall.EINVAL
+			}
+
+			/*
+				Parse app metadata.
+			*/
+
+			id := args[0]
+			pathSet := pathSetByApp(id)
+			a := loadAppInfo(pathSet.metaPath, func() {})
+			if a.ID != id {
+				log.Printf("app %q claims to have identifier %q", id, a.ID)
+				return syscall.EBADE
+			}
+
+			/*
+				Prepare nixGL.
+			*/
+
+			if a.GPU && flagAutoDrivers {
+				withNixDaemon(ctx, "nix-gl", []string{
+					"mkdir -p /nix/.nixGL/auto",
+					"rm -rf /nix/.nixGL/auto",
+					"export NIXPKGS_ALLOW_UNFREE=1",
+					"nix build --impure " +
+						"--out-link /nix/.nixGL/auto/opengl " +
+						"--override-input nixpkgs path:/etc/nixpkgs " +
+						"path:" + a.NixGL,
+					"nix build --impure " +
+						"--out-link /nix/.nixGL/auto/vulkan " +
+						"--override-input nixpkgs path:/etc/nixpkgs " +
+						"path:" + a.NixGL + "#nixVulkanNvidia",
+				}, true, func(config *hst.Config) *hst.Config {
+					config.Container.Filesystem = append(config.Container.Filesystem, []*hst.FilesystemConfig{
+						{Src: "/etc/resolv.conf"},
+						{Src: "/sys/block"},
+						{Src: "/sys/bus"},
+						{Src: "/sys/class"},
+						{Src: "/sys/dev"},
+						{Src: "/sys/devices"},
+					}...)
+					appendGPUFilesystem(config)
+					return config
+				}, a, pathSet, flagDropShellNixGL, func() {})
+			}
+
+			/*
+				Create app configuration.
+			*/
+
+			argv := make([]string, 1, len(args))
+			if !flagDropShell {
+				argv[0] = a.Launcher
+			} else {
+				argv[0] = shellPath
+			}
+			argv = append(argv, args[1:]...)
+
+			config := a.toFst(pathSet, argv, flagDropShell)
+
+			/*
+				Expose GPU devices.
+			*/
+
+			if a.GPU {
+				config.Container.Filesystem = append(config.Container.Filesystem,
+					&hst.FilesystemConfig{Src: path.Join(pathSet.nixPath, ".nixGL"), Dst: path.Join(hst.Tmp, "nixGL")})
+				appendGPUFilesystem(config)
+			}
+
+			/*
+				Spawn app.
+			*/
+
+			mustRunApp(ctx, config, func() {})
+			return errSuccess
+		}).
+			Flag(&flagDropShellNixGL, "s", command.BoolFlag(false), "Drop to a shell on nixGL build").
+			Flag(&flagAutoDrivers, "auto-drivers", command.BoolFlag(false), "Attempt automatic opengl driver detection")
+	}
+
+	c.MustParse(os.Args[1:], func(err error) {
+		hlog.Verbosef("command returned %v", err)
+		if errors.Is(err, errSuccess) {
+			hlog.BeforeExit()
+			os.Exit(0)
+		}
+	})
+	log.Fatal("unreachable")
+}
diff --git a/cmd/hpkg/paths.go b/cmd/hpkg/paths.go
new file mode 100644
index 00000000..11715fb2
--- /dev/null
+++ b/cmd/hpkg/paths.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"path"
+	"strconv"
+	"sync/atomic"
+
+	"hakurei.app/hst"
+	"hakurei.app/internal/hlog"
+)
+
+var (
+	dataHome string
+)
+
+func init() {
+	// dataHome
+	if p, ok := os.LookupEnv("HAKUREI_DATA_HOME"); ok {
+		dataHome = p
+	} else {
+		dataHome = "/var/lib/hakurei/" + strconv.Itoa(os.Getuid())
+	}
+}
+
+func lookPath(file string) string {
+	if p, err := exec.LookPath(file); err != nil {
+		log.Fatalf("%s: command not found", file)
+		return ""
+	} else {
+		return p
+	}
+}
+
+var beforeRunFail = new(atomic.Pointer[func()])
+
+func mustRun(name string, arg ...string) {
+	hlog.Verbosef("spawning process: %q %q", name, arg)
+	cmd := exec.Command(name, arg...)
+	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
+	if err := cmd.Run(); err != nil {
+		if f := beforeRunFail.Swap(nil); f != nil {
+			(*f)()
+		}
+		log.Fatalf("%s: %v", name, err)
+	}
+}
+
+type appPathSet struct {
+	// ${dataHome}/${id}
+	baseDir string
+	// ${baseDir}/app
+	metaPath string
+	// ${baseDir}/files
+	homeDir string
+	// ${baseDir}/cache
+	cacheDir string
+	// ${baseDir}/cache/nix
+	nixPath string
+}
+
+func pathSetByApp(id string) *appPathSet {
+	pathSet := new(appPathSet)
+	pathSet.baseDir = path.Join(dataHome, id)
+	pathSet.metaPath = path.Join(pathSet.baseDir, "app")
+	pathSet.homeDir = path.Join(pathSet.baseDir, "files")
+	pathSet.cacheDir = path.Join(pathSet.baseDir, "cache")
+	pathSet.nixPath = path.Join(pathSet.cacheDir, "nix")
+	return pathSet
+}
+
+func appendGPUFilesystem(config *hst.Config) {
+	config.Container.Filesystem = append(config.Container.Filesystem, []*hst.FilesystemConfig{
+		// flatpak commit 763a686d874dd668f0236f911de00b80766ffe79
+		{Src: "/dev/dri", Device: true},
+		// mali
+		{Src: "/dev/mali", Device: true},
+		{Src: "/dev/mali0", Device: true},
+		{Src: "/dev/umplock", Device: true},
+		// nvidia
+		{Src: "/dev/nvidiactl", Device: true},
+		{Src: "/dev/nvidia-modeset", Device: true},
+		// nvidia OpenCL/CUDA
+		{Src: "/dev/nvidia-uvm", Device: true},
+		{Src: "/dev/nvidia-uvm-tools", Device: true},
+
+		// flatpak commit d2dff2875bb3b7e2cd92d8204088d743fd07f3ff
+		{Src: "/dev/nvidia0", Device: true}, {Src: "/dev/nvidia1", Device: true},
+		{Src: "/dev/nvidia2", Device: true}, {Src: "/dev/nvidia3", Device: true},
+		{Src: "/dev/nvidia4", Device: true}, {Src: "/dev/nvidia5", Device: true},
+		{Src: "/dev/nvidia6", Device: true}, {Src: "/dev/nvidia7", Device: true},
+		{Src: "/dev/nvidia8", Device: true}, {Src: "/dev/nvidia9", Device: true},
+		{Src: "/dev/nvidia10", Device: true}, {Src: "/dev/nvidia11", Device: true},
+		{Src: "/dev/nvidia12", Device: true}, {Src: "/dev/nvidia13", Device: true},
+		{Src: "/dev/nvidia14", Device: true}, {Src: "/dev/nvidia15", Device: true},
+		{Src: "/dev/nvidia16", Device: true}, {Src: "/dev/nvidia17", Device: true},
+		{Src: "/dev/nvidia18", Device: true}, {Src: "/dev/nvidia19", Device: true},
+	}...)
+}
diff --git a/cmd/hpkg/proc.go b/cmd/hpkg/proc.go
new file mode 100644
index 00000000..d374e13d
--- /dev/null
+++ b/cmd/hpkg/proc.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+
+	"hakurei.app/hst"
+	"hakurei.app/internal"
+	"hakurei.app/internal/hlog"
+)
+
+var hakureiPath = internal.MustHakureiPath()
+
+func mustRunApp(ctx context.Context, config *hst.Config, beforeFail func()) {
+	var (
+		cmd *exec.Cmd
+		st  io.WriteCloser
+	)
+
+	if r, w, err := os.Pipe(); err != nil {
+		beforeFail()
+		log.Fatalf("cannot pipe: %v", err)
+	} else {
+		if hlog.Load() {
+			cmd = exec.CommandContext(ctx, hakureiPath, "-v", "app", "3")
+		} else {
+			cmd = exec.CommandContext(ctx, hakureiPath, "app", "3")
+		}
+		cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
+		cmd.ExtraFiles = []*os.File{r}
+		st = w
+	}
+
+	go func() {
+		if err := json.NewEncoder(st).Encode(config); err != nil {
+			beforeFail()
+			log.Fatalf("cannot send configuration: %v", err)
+		}
+	}()
+
+	if err := cmd.Start(); err != nil {
+		beforeFail()
+		log.Fatalf("cannot start hakurei: %v", err)
+	}
+	if err := cmd.Wait(); err != nil {
+		var exitError *exec.ExitError
+		if errors.As(err, &exitError) {
+			beforeFail()
+			internal.Exit(exitError.ExitCode())
+		} else {
+			beforeFail()
+			log.Fatalf("cannot wait: %v", err)
+		}
+	}
+}
diff --git a/cmd/hpkg/test/configuration.nix b/cmd/hpkg/test/configuration.nix
new file mode 100644
index 00000000..ce74228a
--- /dev/null
+++ b/cmd/hpkg/test/configuration.nix
@@ -0,0 +1,62 @@
+{ pkgs, ... }:
+{
+  users.users = {
+    alice = {
+      isNormalUser = true;
+      description = "Alice Foobar";
+      password = "foobar";
+      uid = 1000;
+    };
+  };
+
+  home-manager.users.alice.home.stateVersion = "24.11";
+
+  # Automatically login on tty1 as a normal user:
+  services.getty.autologinUser = "alice";
+
+  environment = {
+    variables = {
+      SWAYSOCK = "/tmp/sway-ipc.sock";
+      WLR_RENDERER = "pixman";
+    };
+  };
+
+  # Automatically configure and start Sway when logging in on tty1:
+  programs.bash.loginShellInit = ''
+    if [ "$(tty)" = "/dev/tty1" ]; then
+      set -e
+
+      mkdir -p ~/.config/sway
+      (sed s/Mod4/Mod1/ /etc/sway/config &&
+      echo 'output * bg ${pkgs.nixos-artwork.wallpapers.simple-light-gray.gnomeFilePath} fill' &&
+      echo 'output Virtual-1 res 1680x1050') > ~/.config/sway/config
+
+      sway --validate
+      systemd-cat --identifier=session sway && touch /tmp/sway-exit-ok
+    fi
+  '';
+
+  programs.sway.enable = true;
+
+  virtualisation = {
+    diskSize = 6 * 1024;
+
+    qemu.options = [
+      # Need to switch to a different GPU driver than the default one (-vga std) so that Sway can launch:
+      "-vga none -device virtio-gpu-pci"
+
+      # Increase zstd performance:
+      "-smp 8"
+    ];
+  };
+
+  environment.hakurei = {
+    enable = true;
+    stateDir = "/var/lib/hakurei";
+    users.alice = 0;
+
+    extraHomeConfig = {
+      home.stateVersion = "23.05";
+    };
+  };
+}
diff --git a/cmd/hpkg/test/default.nix b/cmd/hpkg/test/default.nix
new file mode 100644
index 00000000..4d5e3b02
--- /dev/null
+++ b/cmd/hpkg/test/default.nix
@@ -0,0 +1,34 @@
+{
+  nixosTest,
+  callPackage,
+
+  system,
+  self,
+}:
+let
+  buildPackage = self.buildPackage.${system};
+in
+nixosTest {
+  name = "hpkg";
+  nodes.machine = {
+    environment.etc = {
+      "foot.pkg".source = callPackage ./foot.nix { inherit buildPackage; };
+    };
+
+    imports = [
+      ./configuration.nix
+
+      self.nixosModules.hakurei
+      self.inputs.home-manager.nixosModules.home-manager
+    ];
+  };
+
+  # adapted from nixos sway integration tests
+
+  # testScriptWithTypes:49: error: Cannot call function of unknown type
+  #           (machine.succeed if succeed else machine.execute)(
+  #           ^
+  # Found 1 error in 1 file (checked 1 source file)
+  skipTypeCheck = true;
+  testScript = builtins.readFile ./test.py;
+}
diff --git a/cmd/hpkg/test/foot.nix b/cmd/hpkg/test/foot.nix
new file mode 100644
index 00000000..76b677ac
--- /dev/null
+++ b/cmd/hpkg/test/foot.nix
@@ -0,0 +1,48 @@
+{
+  lib,
+  buildPackage,
+  foot,
+  wayland-utils,
+  inconsolata,
+}:
+
+buildPackage {
+  name = "foot";
+  inherit (foot) version;
+
+  identity = 2;
+  id = "org.codeberg.dnkl.foot";
+
+  modules = [
+    {
+      home.packages = [
+        foot
+
+        # For wayland-info:
+        wayland-utils
+      ];
+    }
+  ];
+
+  nixosModules = [
+    {
+      # To help with OCR:
+      environment.etc."xdg/foot/foot.ini".text = lib.generators.toINI { } {
+        main = {
+          font = "inconsolata:size=14";
+        };
+        colors = rec {
+          foreground = "000000";
+          background = "ffffff";
+          regular2 = foreground;
+        };
+      };
+
+      fonts.packages = [ inconsolata ];
+    }
+  ];
+
+  script = ''
+    exec foot "$@"
+  '';
+}
diff --git a/cmd/hpkg/test/test.py b/cmd/hpkg/test/test.py
new file mode 100644
index 00000000..c9944354
--- /dev/null
+++ b/cmd/hpkg/test/test.py
@@ -0,0 +1,108 @@
+import json
+import shlex
+
+q = shlex.quote
+NODE_GROUPS = ["nodes", "floating_nodes"]
+
+
+def swaymsg(command: str = "", succeed=True, type="command"):
+    assert command != "" or type != "command", "Must specify command or type"
+    shell = q(f"swaymsg -t {q(type)} -- {q(command)}")
+    with machine.nested(
+            f"sending swaymsg {shell!r}" + " (allowed to fail)" * (not succeed)
+    ):
+        ret = (machine.succeed if succeed else machine.execute)(
+            f"su - alice -c {shell}"
+        )
+
+    # execute also returns a status code, but disregard.
+    if not succeed:
+        _, ret = ret
+
+    if not succeed and not ret:
+        return None
+
+    parsed = json.loads(ret)
+    return parsed
+
+
+def walk(tree):
+    yield tree
+    for group in NODE_GROUPS:
+        for node in tree.get(group, []):
+            yield from walk(node)
+
+
+def wait_for_window(pattern):
+    def func(last_chance):
+        nodes = (node["name"] for node in walk(swaymsg(type="get_tree")))
+
+        if last_chance:
+            nodes = list(nodes)
+            machine.log(f"Last call! Current list of windows: {nodes}")
+
+        return any(pattern in name for name in nodes)
+
+    retry(func)
+
+
+def collect_state_ui(name):
+    swaymsg(f"exec hakurei ps > '/tmp/{name}.ps'")
+    machine.copy_from_vm(f"/tmp/{name}.ps", "")
+    swaymsg(f"exec hakurei --json ps > '/tmp/{name}.json'")
+    machine.copy_from_vm(f"/tmp/{name}.json", "")
+    machine.screenshot(name)
+
+
+def check_state(name, enablements):
+    instances = json.loads(machine.succeed("sudo -u alice -i XDG_RUNTIME_DIR=/run/user/1000 hakurei --json ps"))
+    if len(instances) != 1:
+        raise Exception(f"unexpected state length {len(instances)}")
+    instance = next(iter(instances.values()))
+
+    config = instance['config']
+
+    if len(config['args']) != 1 or not (config['args'][0].startswith("/nix/store/")) or f"hakurei-{name}-" not in (config['args'][0]):
+        raise Exception(f"unexpected args {instance['config']['args']}")
+
+    if config['enablements'] != enablements:
+        raise Exception(f"unexpected enablements {instance['config']['enablements']}")
+
+
+start_all()
+machine.wait_for_unit("multi-user.target")
+
+# To check hakurei's version:
+print(machine.succeed("sudo -u alice -i hakurei version"))
+
+# Wait for Sway to complete startup:
+machine.wait_for_file("/run/user/1000/wayland-1")
+machine.wait_for_file("/tmp/sway-ipc.sock")
+
+# Prepare hpkg directory:
+machine.succeed("install -dm 0700 -o alice -g users /var/lib/hakurei/1000")
+
+# Install hpkg app:
+swaymsg("exec hpkg -v install /etc/foot.pkg && touch /tmp/hpkg-install-ok")
+machine.wait_for_file("/tmp/hpkg-install-ok")
+
+# Start app (foot) with Wayland enablement:
+swaymsg("exec hpkg -v start org.codeberg.dnkl.foot")
+wait_for_window("hakurei@machine-foot")
+machine.send_chars("clear; wayland-info && touch /tmp/success-client\n")
+machine.wait_for_file("/tmp/hakurei.1000/tmpdir/2/success-client")
+collect_state_ui("app_wayland")
+check_state("foot", 13)
+# Verify acl on XDG_RUNTIME_DIR:
+print(machine.succeed("getfacl --absolute-names --omit-header --numeric /run/user/1000 | grep 1000002"))
+machine.send_chars("exit\n")
+machine.wait_until_fails("pgrep foot")
+# Verify acl cleanup on XDG_RUNTIME_DIR:
+machine.wait_until_fails("getfacl --absolute-names --omit-header --numeric /run/user/1000 | grep 1000002")
+
+# Exit Sway and verify process exit status 0:
+swaymsg("exit", succeed=False)
+machine.wait_for_file("/tmp/sway-exit-ok")
+
+# Print hakurei runDir contents:
+print(machine.succeed("find /run/user/1000/hakurei"))
\ No newline at end of file
diff --git a/cmd/hpkg/with.go b/cmd/hpkg/with.go
new file mode 100644
index 00000000..7d9fc7b8
--- /dev/null
+++ b/cmd/hpkg/with.go
@@ -0,0 +1,114 @@
+package main
+
+import (
+	"context"
+	"path"
+	"strings"
+
+	"hakurei.app/container/seccomp"
+	"hakurei.app/hst"
+	"hakurei.app/internal"
+)
+
+func withNixDaemon(
+	ctx context.Context,
+	action string, command []string, net bool, updateConfig func(config *hst.Config) *hst.Config,
+	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func(),
+) {
+	mustRunAppDropShell(ctx, updateConfig(&hst.Config{
+		ID: app.ID,
+
+		Path: shellPath,
+		Args: []string{shellPath, "-lc", "rm -f /nix/var/nix/daemon-socket/socket && " +
+			// start nix-daemon
+			"nix-daemon --store / & " +
+			// wait for socket to appear
+			"(while [ ! -S /nix/var/nix/daemon-socket/socket ]; do sleep 0.01; done) && " +
+			// create directory so nix stops complaining
+			"mkdir -p /nix/var/nix/profiles/per-user/root/channels && " +
+			strings.Join(command, " && ") +
+			// terminate nix-daemon
+			" && pkill nix-daemon",
+		},
+
+		Username: "hakurei",
+		Shell:    shellPath,
+		Data:     pathSet.homeDir,
+		Dir:      path.Join("/data/data", app.ID),
+		ExtraPerms: []*hst.ExtraPermConfig{
+			{Path: dataHome, Execute: true},
+			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
+		},
+
+		Identity: app.Identity,
+
+		Container: &hst.ContainerConfig{
+			Hostname:     formatHostname(app.Name) + "-" + action,
+			Userns:       true, // nix sandbox requires userns
+			Net:          net,
+			SeccompFlags: seccomp.AllowMultiarch,
+			Tty:          dropShell,
+			Filesystem: []*hst.FilesystemConfig{
+				{Src: pathSet.nixPath, Dst: "/nix", Write: true, Must: true},
+			},
+			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,
+		},
+	}), dropShell, beforeFail)
+}
+
+func withCacheDir(
+	ctx context.Context,
+	action string, command []string, workDir string,
+	app *appInfo, pathSet *appPathSet, dropShell bool, beforeFail func()) {
+	mustRunAppDropShell(ctx, &hst.Config{
+		ID: app.ID,
+
+		Path: shellPath,
+		Args: []string{shellPath, "-lc", strings.Join(command, " && ")},
+
+		Username: "nixos",
+		Shell:    shellPath,
+		Data:     pathSet.cacheDir, // this also ensures cacheDir via shim
+		Dir:      path.Join("/data/data", app.ID, "cache"),
+		ExtraPerms: []*hst.ExtraPermConfig{
+			{Path: dataHome, Execute: true},
+			{Ensure: true, Path: pathSet.baseDir, Read: true, Write: true, Execute: true},
+			{Path: workDir, Execute: true},
+		},
+
+		Identity: app.Identity,
+
+		Container: &hst.ContainerConfig{
+			Hostname:     formatHostname(app.Name) + "-" + action,
+			SeccompFlags: seccomp.AllowMultiarch,
+			Tty:          dropShell,
+			Filesystem: []*hst.FilesystemConfig{
+				{Src: path.Join(workDir, "nix"), Dst: "/nix", Must: true},
+				{Src: workDir, Dst: path.Join(hst.Tmp, "bundle"), Must: true},
+			},
+			Link: [][2]string{
+				{app.CurrentSystem, "/run/current-system"},
+				{"/run/current-system/sw/bin", "/bin"},
+				{"/run/current-system/sw/bin", "/usr/bin"},
+			},
+			Etc:     path.Join(workDir, "etc"),
+			AutoEtc: true,
+		},
+	}, dropShell, beforeFail)
+}
+
+func mustRunAppDropShell(ctx context.Context, config *hst.Config, dropShell bool, beforeFail func()) {
+	if dropShell {
+		config.Args = []string{shellPath, "-l"}
+		mustRunApp(ctx, config, beforeFail)
+		beforeFail()
+		internal.Exit(0)
+	}
+	mustRunApp(ctx, config, beforeFail)
+}