/* vi:set et sw=2 sts=2 cin cino=t0,f0,(0,{s,>2s,n-s,^-s,e-s:
 * Copyright © 2014-2019 Red Hat, Inc
 * Copyright © 2024 GNOME Foundation, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *       Alexander Larsson <alexl@redhat.com>
 *       Hubert Figuière <hub@figuiere.net>
 */

#include "config.h"

#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <gio/gdesktopappinfo.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/utsname.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/vfs.h>
#include <sys/wait.h>
#include <sys/personality.h>
#include <grp.h>
#include <unistd.h>
#include <gio/gunixfdlist.h>
#ifdef HAVE_DCONF
#include <dconf/dconf.h>
#endif
#ifdef HAVE_LIBMALCONTENT
#include <libmalcontent/malcontent.h>
#endif

#include "flatpak-syscalls-private.h"

#ifdef ENABLE_SECCOMP
#include <seccomp.h>
#endif

#include <glib/gi18n-lib.h>

#include <gio/gio.h>
#include "libglnx.h"

#include "flatpak-dbus-generated.h"
#include "flatpak-run-dbus-private.h"
#include "flatpak-run-private.h"
#include "flatpak-run-sockets-private.h"
#include "flatpak-run-wayland-private.h"
#include "flatpak-utils-base-private.h"
#include "flatpak-dir-private.h"
#include "flatpak-dir-utils-private.h"
#include "flatpak-instance-private.h"
#include "flatpak-systemd-dbus-generated.h"
#include "flatpak-document-dbus-generated.h"
#include "flatpak-error.h"
#include "session-helper/flatpak-session-helper.h"

#define DEFAULT_SHELL "/bin/sh"

typedef FlatpakSessionHelper AutoFlatpakSessionHelper;
G_DEFINE_AUTOPTR_CLEANUP_FUNC (AutoFlatpakSessionHelper, g_object_unref)

typedef XdpDbusDocuments AutoXdpDbusDocuments;
G_DEFINE_AUTOPTR_CLEANUP_FUNC (AutoXdpDbusDocuments, g_object_unref)

/* flags enum for org.freedesktop.portal.Documents.AddFull */
typedef enum {
  DOCUMENT_ADD_FLAGS_REUSE_EXISTING             = (1 << 0),
  DOCUMENT_ADD_FLAGS_PERSISTENT                 = (1 << 1),
  DOCUMENT_ADD_FLAGS_AS_NEEDED_BY_APP           = (1 << 2),
  DOCUMENT_ADD_FLAGS_DIRECTORY                  = (1 << 3),

  DOCUMENT_ADD_FLAGS_FLAGS_ALL                  = ((1 << 4) - 1)
} DocumentAddFullFlags;

static int
flatpak_extension_compare_by_path (gconstpointer _a,
                                   gconstpointer _b)
{
  const FlatpakExtension *a = _a;
  const FlatpakExtension *b = _b;

  return g_strcmp0 (a->directory, b->directory);
}

void
flatpak_run_extend_ld_path (FlatpakBwrap *bwrap,
                            const char *prepend,
                            const char *append)
{
  g_autoptr(GString) ld_library_path = g_string_new (g_environ_getenv (bwrap->envp, "LD_LIBRARY_PATH"));

  if (prepend != NULL && *prepend != '\0')
    {
      if (ld_library_path->len > 0)
        g_string_prepend (ld_library_path, ":");

      g_string_prepend (ld_library_path, prepend);
    }

  if (append != NULL && *append != '\0')
    {
      if (ld_library_path->len > 0)
        g_string_append (ld_library_path, ":");

      g_string_append (ld_library_path, append);
    }

  flatpak_bwrap_set_env (bwrap, "LD_LIBRARY_PATH", ld_library_path->str, TRUE);
}

gboolean
flatpak_run_add_extension_args (FlatpakBwrap      *bwrap,
                                GKeyFile          *metakey,
                                FlatpakDecomposed *ref,
                                gboolean           use_ld_so_cache,
                                const char        *target_path,
                                char             **extensions_out,
                                char             **ld_path_out,
                                GCancellable      *cancellable,
                                GError           **error)
{
  g_autoptr(GString) used_extensions = g_string_new ("");
  GList *extensions, *path_sorted_extensions, *l;
  g_autoptr(GString) ld_library_path = g_string_new ("");
  int count = 0;
  g_autoptr(GHashTable) mounted_tmpfs =
    g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
  g_autoptr(GHashTable) created_symlink =
    g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
  g_autofree char *arch = flatpak_decomposed_dup_arch (ref);
  const char *branch = flatpak_decomposed_get_branch (ref);

  g_return_val_if_fail (target_path != NULL, FALSE);

  extensions = flatpak_list_extensions (metakey, arch, branch);

  /* First we apply all the bindings, they are sorted alphabetically in order for parent directory
     to be mounted before child directories */
  path_sorted_extensions = g_list_copy (extensions);
  path_sorted_extensions = g_list_sort (path_sorted_extensions, flatpak_extension_compare_by_path);

  for (l = path_sorted_extensions; l != NULL; l = l->next)
    {
      FlatpakExtension *ext = l->data;
      g_autofree char *directory = g_build_filename (target_path, ext->directory, NULL);
      g_autofree char *full_directory = g_build_filename (directory, ext->subdir_suffix, NULL);
      g_autofree char *ref_file = g_build_filename (full_directory, ".ref", NULL);
      g_autofree char *real_ref = g_build_filename (ext->files_path, ext->directory, ".ref", NULL);

      if (ext->needs_tmpfs)
        {
          g_autofree char *parent = g_path_get_dirname (directory);

          if (!g_hash_table_contains (mounted_tmpfs, parent))
            {
              flatpak_bwrap_add_args (bwrap,
                                      "--tmpfs", parent,
                                      NULL);
              g_hash_table_add (mounted_tmpfs, g_steal_pointer (&parent));
            }
        }

      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", ext->files_path, full_directory,
                              NULL);

      if (g_file_test (real_ref, G_FILE_TEST_EXISTS))
        flatpak_bwrap_add_args (bwrap,
                                "--lock-file", ref_file,
                                NULL);
    }

  g_list_free (path_sorted_extensions);

  /* Then apply library directories and file merging, in extension prio order */

  for (l = extensions; l != NULL; l = l->next)
    {
      FlatpakExtension *ext = l->data;
      g_autofree char *directory = g_build_filename (target_path, ext->directory, NULL);
      g_autofree char *full_directory = g_build_filename (directory, ext->subdir_suffix, NULL);
      int i;

      if (used_extensions->len > 0)
        g_string_append (used_extensions, ";");
      g_string_append (used_extensions, ext->installed_id);
      g_string_append (used_extensions, "=");
      if (ext->commit != NULL)
        g_string_append (used_extensions, ext->commit);
      else
        g_string_append (used_extensions, "local");

      if (ext->add_ld_path)
        {
          g_autofree char *ld_path = g_build_filename (full_directory, ext->add_ld_path, NULL);

          if (use_ld_so_cache)
            {
              g_autofree char *contents = g_strconcat (ld_path, "\n", NULL);
              /* We prepend app or runtime and a counter in order to get the include order correct for the conf files */
              g_autofree char *ld_so_conf_file = g_strdup_printf ("%s-%03d-%s.conf", flatpak_decomposed_get_kind_str (ref), ++count, ext->installed_id);
              g_autofree char *ld_so_conf_file_path = g_build_filename ("/run/flatpak/ld.so.conf.d", ld_so_conf_file, NULL);

              if (!flatpak_bwrap_add_args_data (bwrap, "ld-so-conf",
                                                contents, -1, ld_so_conf_file_path, error))
                return FALSE;
            }
          else
            {
              if (ld_library_path->len != 0)
                g_string_append (ld_library_path, ":");
              g_string_append (ld_library_path, ld_path);
            }
        }

      for (i = 0; ext->merge_dirs != NULL && ext->merge_dirs[i] != NULL; i++)
        {
          g_autofree char *parent = g_path_get_dirname (directory);
          g_autofree char *merge_dir = g_build_filename (parent, ext->merge_dirs[i], NULL);
          g_autofree char *source_dir = g_build_filename (ext->files_path, ext->merge_dirs[i], NULL);
          g_auto(GLnxDirFdIterator) source_iter = { 0 };
          struct dirent *dent;

          if (glnx_dirfd_iterator_init_at (AT_FDCWD, source_dir, TRUE, &source_iter, NULL))
            {
              while (glnx_dirfd_iterator_next_dent (&source_iter, &dent, NULL, NULL) && dent != NULL)
                {
                  g_autofree char *symlink_path = g_build_filename (merge_dir, dent->d_name, NULL);
                  /* Only create the first, because extensions are listed in prio order */
                  if (!g_hash_table_contains (created_symlink, symlink_path))
                    {
                      g_autofree char *symlink = g_build_filename (directory, ext->merge_dirs[i], dent->d_name, NULL);
                      flatpak_bwrap_add_args (bwrap,
                                              "--symlink", symlink, symlink_path,
                                              NULL);
                      g_hash_table_add (created_symlink, g_steal_pointer (&symlink_path));
                    }
                }
            }
        }
    }

  g_list_free_full (extensions, (GDestroyNotify) flatpak_extension_free);

  if (extensions_out)
    *extensions_out = g_string_free (g_steal_pointer (&used_extensions), FALSE);

  if (ld_path_out)
    *ld_path_out = g_string_free (g_steal_pointer (&ld_library_path), FALSE);

  return TRUE;
}

static gboolean
check_usb_portal (void)
{
  g_autoptr(GDBusConnection) bus = NULL;
  g_autoptr(GVariant) ret = NULL;
  g_autoptr(GError) error = NULL;

  bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, NULL);
  if (!bus)
    return FALSE;

  ret = g_dbus_connection_call_sync (bus,
                                     "org.freedesktop.portal.Desktop",
                                     "/org/freedesktop/portal/desktop",
                                     "org.freedesktop.DBus.Properties",
                                     "Get",
                                     g_variant_new ("(ss)",
                                                    "org.freedesktop.portal.Usb",
                                                    "version"),
                                     G_VARIANT_TYPE ("(v)"),
                                     G_DBUS_CALL_FLAGS_NONE,
                                     -1,
                                     NULL,
                                     &error);
  if (ret)
    return TRUE;

  if (!g_error_matches (error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS) &&
      !g_error_matches (error, G_DBUS_ERROR, G_DBUS_ERROR_SERVICE_UNKNOWN) &&
      !g_error_matches (error, G_DBUS_ERROR, G_DBUS_ERROR_NAME_HAS_NO_OWNER))
    g_warning ("Querying availability of USB Portal failed: %s", error->message);

  return FALSE;
}

static gboolean
flatpak_run_has_usb_portal (void)
{
  static gsize usb_portal_once = 0;
  enum {
    HAS_USB_PORTAL_TRUE = 1,
    HAS_USB_PORTAL_FALSE = 2
  };

  if (g_once_init_enter (&usb_portal_once))
    {
      g_once_init_leave (&usb_portal_once, check_usb_portal () ?
                                           HAS_USB_PORTAL_TRUE :
                                           HAS_USB_PORTAL_FALSE);
    }

  return usb_portal_once == HAS_USB_PORTAL_TRUE;
}

static gboolean
flatpak_run_evaluate_conditions (FlatpakContextConditions condition)
{
  switch (condition)
    {
    case FLATPAK_CONTEXT_CONDITION_HAS_WAYLAND:
      return flatpak_run_has_wayland ();
    case FLATPAK_CONTEXT_CONDITION_HAS_USB_PORTAL:
      return flatpak_run_has_usb_portal ();
    default:
      return FALSE;
    }
}

/*
 * @per_app_dir_lock_fd: If >= 0, make use of per-app directories in
 *  the host's XDG_RUNTIME_DIR to share /tmp between instances.
 */
gboolean
flatpak_run_add_environment_args (FlatpakBwrap           *bwrap,
                                  const char             *app_info_path,
                                  FlatpakRunFlags         flags,
                                  const char             *app_id,
                                  FlatpakContext         *context,
                                  FlatpakContextShares    shares,
                                  FlatpakContextDevices   devices,
                                  FlatpakContextSockets   sockets,
                                  FlatpakContextFeatures  features,
                                  GFile                  *app_id_dir,
                                  GPtrArray              *previous_app_id_dirs,
                                  int                     per_app_dir_lock_fd,
                                  const char             *instance_id,
                                  FlatpakExports        **exports_out,
                                  GCancellable           *cancellable,
                                  GError                **error)
{
  g_autoptr(GError) my_error = NULL;
  g_autoptr(FlatpakExports) exports = NULL;
  g_autoptr(FlatpakBwrap) proxy_arg_bwrap = flatpak_bwrap_new (flatpak_bwrap_empty_env);
  g_autofree char *xdg_dirs_conf = NULL;
  gboolean home_access = FALSE;
  gboolean sandboxed = (flags & FLATPAK_RUN_FLAG_SANDBOX) != 0;

  if ((shares & FLATPAK_CONTEXT_SHARED_IPC) == 0)
    {
      g_info ("Disallowing ipc access");
      flatpak_bwrap_add_args (bwrap, "--unshare-ipc", NULL);
    }

  if ((shares & FLATPAK_CONTEXT_SHARED_NETWORK) == 0)
    {
      g_info ("Disallowing network access");
      flatpak_bwrap_add_args (bwrap, "--unshare-net", NULL);
    }

  if (devices & FLATPAK_CONTEXT_DEVICE_ALL)
    {
      flatpak_bwrap_add_args (bwrap,
                              "--dev-bind", "/dev", "/dev",
                              NULL);
      /* Don't expose the host /dev/shm, just the device nodes, unless explicitly allowed */
      if (g_file_test ("/dev/shm", G_FILE_TEST_IS_DIR))
        {
          if (devices & FLATPAK_CONTEXT_DEVICE_SHM)
            {
              /* Don't do anything special: include shm in the
               * shared /dev. The host and all sandboxes and subsandboxes
               * all share /dev/shm */
            }
          else if ((features & FLATPAK_CONTEXT_FEATURE_PER_APP_DEV_SHM)
                   && per_app_dir_lock_fd >= 0)
            {
              g_autofree char *shared_dev_shm = NULL;

              /* The host and the original sandbox have separate /dev/shm,
               * but we want other instances to be able to share /dev/shm with
               * the first sandbox (except for subsandboxes run with
               * flatpak-spawn --sandbox, which will have their own). */
              if (!flatpak_instance_ensure_per_app_dev_shm (app_id,
                                                            per_app_dir_lock_fd,
                                                            &shared_dev_shm,
                                                            error))
                return FALSE;

              flatpak_bwrap_add_args (bwrap,
                                      "--bind", shared_dev_shm, "/dev/shm",
                                      NULL);
            }
          else
            {
              /* The host, the original sandbox and each subsandbox
               * each have a separate /dev/shm. */
              flatpak_bwrap_add_args (bwrap,
                                      "--tmpfs", "/dev/shm",
                                      NULL);
            }
        }
      else if (g_file_test ("/dev/shm", G_FILE_TEST_IS_SYMLINK))
        {
          g_autofree char *link = flatpak_readlink ("/dev/shm", NULL);

          /* On debian (with sysv init) the host /dev/shm is a symlink to /run/shm, so we can't
             mount on top of it. */
          if (g_strcmp0 (link, "/run/shm") == 0)
            {
              if (devices & FLATPAK_CONTEXT_DEVICE_SHM &&
                  g_file_test ("/run/shm", G_FILE_TEST_IS_DIR))
                {
                  flatpak_bwrap_add_args (bwrap,
                                          "--bind", "/run/shm", "/run/shm",
                                          NULL);
                }
              else if ((features & FLATPAK_CONTEXT_FEATURE_PER_APP_DEV_SHM)
                       && per_app_dir_lock_fd >= 0)
                {
                  g_autofree char *shared_dev_shm = NULL;

                  /* The host and the original sandbox have separate /dev/shm,
                   * but we want other instances to be able to share /dev/shm,
                   * except for flatpak-spawn --subsandbox. */
                  if (!flatpak_instance_ensure_per_app_dev_shm (app_id,
                                                                per_app_dir_lock_fd,
                                                                &shared_dev_shm,
                                                                error))
                    return FALSE;

                  flatpak_bwrap_add_args (bwrap,
                                          "--bind", shared_dev_shm, "/run/shm",
                                          NULL);
                }
              else
                {
                  flatpak_bwrap_add_args (bwrap,
                                          "--dir", "/run/shm",
                                          NULL);
                }
            }
          else
            g_warning ("Unexpected /dev/shm symlink %s", link);
        }
    }
  else
    {
      flatpak_bwrap_add_args (bwrap,
                              "--dev", "/dev",
                              NULL);

      flatpak_bwrap_add_args (bwrap, "--dev-bind-try", "/dev/ntsync", "/dev/ntsync", NULL);

      if (devices & FLATPAK_CONTEXT_DEVICE_USB)
        {
          g_info ("Allowing USB device access.");

          if (g_file_test ("/dev/bus/usb", G_FILE_TEST_IS_DIR))
              flatpak_bwrap_add_args (bwrap, "--dev-bind", "/dev/bus/usb", "/dev/bus/usb", NULL);
        }

      if (devices & FLATPAK_CONTEXT_DEVICE_DRI)
        {
          g_info ("Allowing dri access");
          int i;
          static const char * const dri_devices[] = {
            "/dev/dri",
            "/dev/udmabuf",
            /* mali */
            "/dev/mali",
            "/dev/mali0",
            "/dev/umplock",
            /* nvidia */
            "/dev/nvidiactl",
            "/dev/nvidia-modeset",
            /* nvidia OpenCL/CUDA */
            "/dev/nvidia-uvm",
            "/dev/nvidia-uvm-tools",
            /* AMD ROCm/OpenCL */
            "/dev/kfd",
          };

          for (i = 0; i < G_N_ELEMENTS (dri_devices); i++)
            {
              if (g_file_test (dri_devices[i], G_FILE_TEST_EXISTS))
                flatpak_bwrap_add_args (bwrap, "--dev-bind", dri_devices[i], dri_devices[i], NULL);
            }

          /* Each Nvidia card gets its own device.
             This is a fairly arbitrary limit but ASUS sells mining boards supporting 20 in theory. */
          char nvidia_dev[14]; /* /dev/nvidia plus up to 2 digits */
          for (i = 0; i < 20; i++)
            {
              g_snprintf (nvidia_dev, sizeof (nvidia_dev), "/dev/nvidia%d", i);
              if (g_file_test (nvidia_dev, G_FILE_TEST_EXISTS))
                flatpak_bwrap_add_args (bwrap, "--dev-bind", nvidia_dev, nvidia_dev, NULL);
            }
        }

      if (devices & FLATPAK_CONTEXT_DEVICE_INPUT)
        {
          g_info ("Allowing input device access. Note: raw and virtual input currently require --device=all");

          if (g_file_test ("/dev/input", G_FILE_TEST_IS_DIR))
              flatpak_bwrap_add_args (bwrap, "--dev-bind", "/dev/input", "/dev/input", NULL);
        }

      if (devices & FLATPAK_CONTEXT_DEVICE_KVM)
        {
          g_info ("Allowing kvm access");
          if (g_file_test ("/dev/kvm", G_FILE_TEST_EXISTS))
            flatpak_bwrap_add_args (bwrap, "--dev-bind", "/dev/kvm", "/dev/kvm", NULL);
        }

      if (devices & FLATPAK_CONTEXT_DEVICE_SHM)
        {
          /* This is a symlink to /run/shm on debian, so bind to real target */
          g_autofree char *real_dev_shm = realpath ("/dev/shm", NULL);

          g_info ("Allowing /dev/shm access (as %s)", real_dev_shm);
          if (real_dev_shm != NULL)
              flatpak_bwrap_add_args (bwrap, "--bind", real_dev_shm, "/dev/shm", NULL);
        }
      else if ((features & FLATPAK_CONTEXT_FEATURE_PER_APP_DEV_SHM)
               && per_app_dir_lock_fd >= 0)
        {
          g_autofree char *shared_dev_shm = NULL;

          if (!flatpak_instance_ensure_per_app_dev_shm (app_id,
                                                        per_app_dir_lock_fd,
                                                        &shared_dev_shm,
                                                        error))
            return FALSE;

          flatpak_bwrap_add_args (bwrap,
                                  "--bind", shared_dev_shm, "/dev/shm",
                                  NULL);
        }
    }

  exports = flatpak_context_get_exports_full (context,
                                              app_id_dir, previous_app_id_dirs,
                                              TRUE, TRUE,
                                              &xdg_dirs_conf, &home_access);

  if (flatpak_exports_path_is_visible (exports, "/tmp"))
    {
      /* The original sandbox and any subsandboxes are both already
       * going to share /tmp with the host, so by transitivity they will
       * also share it with each other, and with all other instances. */
    }
  else if (per_app_dir_lock_fd >= 0 && !sandboxed)
    {
      g_autofree char *shared_tmp = NULL;

      /* The host and the original sandbox have separate /tmp,
       * but we want other instances to be able to share /tmp with the
       * first sandbox, unless they were created by
       * flatpak-spawn --sandbox.
       *
       * In apply_extra and `flatpak build`, per_app_dir_lock_fd is
       * negative and we skip this. */
      if (!flatpak_instance_ensure_per_app_tmp (app_id,
                                                per_app_dir_lock_fd,
                                                &shared_tmp,
                                                error))
        return FALSE;

      flatpak_bwrap_add_args (bwrap,
                              "--bind", shared_tmp, "/tmp",
                              NULL);
    }

  flatpak_context_append_bwrap_filesystem (context, bwrap, app_id, app_id_dir,
                                           exports, xdg_dirs_conf, home_access);

  flatpak_run_add_socket_args_environment (bwrap, shares, sockets, app_id, instance_id);
  flatpak_run_add_session_dbus_args (bwrap, proxy_arg_bwrap, sockets, context, flags, app_id);
  flatpak_run_add_system_dbus_args (bwrap, proxy_arg_bwrap, sockets, context, flags);
  flatpak_run_add_a11y_dbus_args (bwrap, proxy_arg_bwrap, context, flags, app_id);

  /* Must run this before spawning the dbus proxy, to ensure it
     ends up in the app cgroup */
  if (instance_id)
    {
      if (!flatpak_run_in_transient_unit (app_id, instance_id, &my_error))
        {
          /* We still run along even if we don't get a cgroup, as nothing
             really depends on it. Its just nice to have */
          g_info ("Failed to run in transient scope: %s", my_error->message);
          g_clear_error (&my_error);
        }
    }

  if (!flatpak_run_maybe_start_dbus_proxy (bwrap, proxy_arg_bwrap,
                                           app_info_path, error))
    return FALSE;

  if (exports_out)
    *exports_out = g_steal_pointer (&exports);

  return TRUE;
}

typedef struct
{
  const char *env;
  const char *val;
} ExportData;

static const ExportData default_exports[] = {
  {"PATH", "/app/bin:/usr/bin"},
  /* We always want to unset LD variables to avoid inheriting weird
   * dependencies from the host. But if not using ld.so.cache LD_LIBRARY_PATH
   is later set. */
  {"LD_LIBRARY_PATH", NULL},
  {"LD_PRELOAD", NULL},
  {"LD_AUDIT", NULL},

  {"XDG_CONFIG_DIRS", "/app/etc/xdg:/etc/xdg"},
  {"XDG_DATA_DIRS", "/app/share:/usr/share"},
  {"SHELL", "/bin/sh"},
  /* Unset temporary file paths as they may not exist in the sandbox */
  {"TEMP", NULL},
  {"TEMPDIR", NULL},
  {"TMP", NULL},
  {"TMPDIR", NULL},
  /* We always use /run/user/UID, even if the user's XDG_RUNTIME_DIR
   * outside the sandbox is somewhere else. Don't allow a different
   * setting from outside the sandbox to overwrite this. */
  {"XDG_RUNTIME_DIR", NULL},
  /* Ensure our container environment variable takes precedence over the one
   * set by a container manager. */
  {"container", NULL},
  /* We always make the zoneinfo available at /usr/share/zoneinfo even if it
   * is somewhere else outside of the sandbox. */
  {"TZDIR", NULL},

  /* Some env vars are common enough and will affect the sandbox badly
     if set on the host. We clear these always. If updating this list,
     also update the list in flatpak-run.xml. */
  {"PYTHONPATH", NULL},
  {"PYTHONPYCACHEPREFIX", NULL},
  {"PERLLIB", NULL},
  {"PERL5LIB", NULL},
  {"XCURSOR_PATH", NULL},
  {"GST_PLUGIN_PATH_1_0", NULL},
  {"GST_REGISTRY", NULL},
  {"GST_REGISTRY_1_0", NULL},
  {"GST_PLUGIN_PATH", NULL},
  {"GST_PLUGIN_SYSTEM_PATH", NULL},
  {"GST_PLUGIN_SCANNER", NULL},
  {"GST_PLUGIN_SCANNER_1_0", NULL},
  {"GST_PLUGIN_SYSTEM_PATH_1_0", NULL},
  {"GST_PRESET_PATH", NULL},
  {"GST_PTP_HELPER", NULL},
  {"GST_PTP_HELPER_1_0", NULL},
  {"GST_INSTALL_PLUGINS_HELPER", NULL},
  {"KRB5CCNAME", NULL},
  {"XKB_CONFIG_ROOT", NULL},
  {"GIO_EXTRA_MODULES", NULL},
  {"GDK_BACKEND", NULL},
  {"VK_ADD_DRIVER_FILES", NULL},
  {"VK_ADD_LAYER_PATH", NULL},
  {"VK_DRIVER_FILES", NULL},
  {"VK_ICD_FILENAMES", NULL},
  {"VK_LAYER_PATH", NULL},
  {"__EGL_EXTERNAL_PLATFORM_CONFIG_DIRS", NULL},
  {"__EGL_EXTERNAL_PLATFORM_CONFIG_FILENAMES", NULL},
  {"__EGL_VENDOR_LIBRARY_DIRS", NULL},
  {"__EGL_VENDOR_LIBRARY_FILENAMES", NULL},
};

static const ExportData no_ld_so_cache_exports[] = {
  {"LD_LIBRARY_PATH", "/app/lib"},
};

static const ExportData devel_exports[] = {
  {"ACLOCAL_PATH", "/app/share/aclocal"},
  {"C_INCLUDE_PATH", "/app/include"},
  {"CPLUS_INCLUDE_PATH", "/app/include"},
  {"LDFLAGS", "-L/app/lib "},
  {"PKG_CONFIG_PATH", "/app/lib/pkgconfig:/app/share/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig"},
  {"LC_ALL", "en_US.utf8"},
};

static void
add_exports (GPtrArray        *env_array,
             const ExportData *exports,
             gsize             n_exports)
{
  int i;

  for (i = 0; i < n_exports; i++)
    {
      if (exports[i].val)
        g_ptr_array_add (env_array, g_strdup_printf ("%s=%s", exports[i].env, exports[i].val));
    }
}

char **
flatpak_run_get_minimal_env (gboolean devel, gboolean use_ld_so_cache)
{
  GPtrArray *env_array;
  static const char * const copy[] = {
    "PWD",
    "GDMSESSION",
    "XDG_CURRENT_DESKTOP",
    "XDG_SESSION_DESKTOP",
    "DESKTOP_SESSION",
    "EMAIL_ADDRESS",
    "HOME",
    "HOSTNAME",
    "LOGNAME",
    "REAL_NAME",
    "TERM",
    "USER",
    "USERNAME",
  };
  static const char * const copy_nodevel[] = {
    "LANG",
    "LANGUAGE",
    "LC_ALL",
    "LC_ADDRESS",
    "LC_COLLATE",
    "LC_CTYPE",
    "LC_IDENTIFICATION",
    "LC_MEASUREMENT",
    "LC_MESSAGES",
    "LC_MONETARY",
    "LC_NAME",
    "LC_NUMERIC",
    "LC_PAPER",
    "LC_TELEPHONE",
    "LC_TIME",
  };
  int i;

  env_array = g_ptr_array_new_with_free_func (g_free);

  add_exports (env_array, default_exports, G_N_ELEMENTS (default_exports));

  if (!use_ld_so_cache)
    add_exports (env_array, no_ld_so_cache_exports, G_N_ELEMENTS (no_ld_so_cache_exports));

  if (devel)
    add_exports (env_array, devel_exports, G_N_ELEMENTS (devel_exports));

  for (i = 0; i < G_N_ELEMENTS (copy); i++)
    {
      const char *current = g_getenv (copy[i]);
      if (current)
        g_ptr_array_add (env_array, g_strdup_printf ("%s=%s", copy[i], current));
    }

  if (!devel)
    {
      for (i = 0; i < G_N_ELEMENTS (copy_nodevel); i++)
        {
          const char *current = g_getenv (copy_nodevel[i]);
          if (current)
            g_ptr_array_add (env_array, g_strdup_printf ("%s=%s", copy_nodevel[i], current));
        }
    }

  g_ptr_array_add (env_array, NULL);
  return (char **) g_ptr_array_free (env_array, FALSE);
}

static char **
apply_exports (char            **envp,
               const ExportData *exports,
               gsize             n_exports)
{
  int i;

  for (i = 0; i < n_exports; i++)
    {
      const char *value = exports[i].val;

      if (value)
        envp = g_environ_setenv (envp, exports[i].env, value, TRUE);
      else
        envp = g_environ_unsetenv (envp, exports[i].env);
    }

  return envp;
}

static void
flatpak_run_apply_env_clear (FlatpakBwrap *bwrap, gboolean clear_env)
{
  if (!clear_env)
    return;

  flatpak_bwrap_add_args (bwrap, "--clearenv", NULL);
}

void
flatpak_run_apply_env_default (FlatpakBwrap *bwrap, gboolean use_ld_so_cache)
{
  bwrap->envp = apply_exports (bwrap->envp, default_exports, G_N_ELEMENTS (default_exports));

  if (!use_ld_so_cache)
    bwrap->envp = apply_exports (bwrap->envp, no_ld_so_cache_exports, G_N_ELEMENTS (no_ld_so_cache_exports));
}

static void
flatpak_run_apply_env_prompt (FlatpakBwrap *bwrap, const char *app_id)
{
  /* A custom shell prompt. FLATPAK_ID is always set.
   * PS1 can be overwritten by runtime metadata or by --env overrides
   */
  flatpak_bwrap_set_env (bwrap, "FLATPAK_ID", app_id, TRUE);
  flatpak_bwrap_set_env (bwrap, "PS1", "[📦 $FLATPAK_ID \\W]\\$ ", FALSE);
}

void
flatpak_run_apply_env_vars (FlatpakBwrap *bwrap, FlatpakContext *context)
{
  GHashTableIter iter;
  gpointer key, value;

  g_hash_table_iter_init (&iter, context->env_vars);
  while (g_hash_table_iter_next (&iter, &key, &value))
    {
      const char *var = key;
      const char *val = value;

      if (val)
        flatpak_bwrap_set_env (bwrap, var, val, TRUE);
      else
        flatpak_bwrap_unset_env (bwrap, var);
    }
}

gboolean
flatpak_ensure_data_dir (GFile        *app_id_dir,
                         GCancellable *cancellable,
                         GError      **error)
{
  g_autoptr(GFile) data_dir = g_file_get_child (app_id_dir, "data");
  g_autoptr(GFile) cache_dir = g_file_get_child (app_id_dir, "cache");
  g_autoptr(GFile) fontconfig_cache_dir = g_file_get_child (cache_dir, "fontconfig");
  g_autoptr(GFile) tmp_dir = g_file_get_child (cache_dir, "tmp");
  g_autoptr(GFile) config_dir = g_file_get_child (app_id_dir, "config");
  g_autoptr(GFile) state_dir = g_file_get_child (app_id_dir, ".local/state");

  if (!flatpak_mkdir_p (data_dir, cancellable, error))
    return FALSE;

  if (!flatpak_mkdir_p (cache_dir, cancellable, error))
    return FALSE;

  if (!flatpak_mkdir_p (fontconfig_cache_dir, cancellable, error))
    return FALSE;

  if (!flatpak_mkdir_p (tmp_dir, cancellable, error))
    return FALSE;

  if (!flatpak_mkdir_p (config_dir, cancellable, error))
    return FALSE;

  if (!flatpak_mkdir_p (state_dir, cancellable, error))
    return FALSE;

  return TRUE;
}

struct JobData
{
  char      *job;
  GMainLoop *main_loop;
};

static void
job_removed_cb (SystemdManager *manager,
                guint32         id,
                char           *job,
                char           *unit,
                char           *result,
                struct JobData *data)
{
  if (strcmp (job, data->job) == 0)
    g_main_loop_quit (data->main_loop);
}

static gchar *
systemd_unit_name_escape (const gchar *in)
{
  /* Adapted from systemd source */
  GString * const str = g_string_sized_new (strlen (in));

  for (; *in; in++)
    {
      if (g_ascii_isalnum (*in) || *in == ':' || *in == '_' || *in == '.')
        g_string_append_c (str, *in);
      else
        g_string_append_printf (str, "\\x%02x", *in);
    }
  return g_string_free (str, FALSE);
}

gboolean
flatpak_run_in_transient_unit (const char  *app_id,
                               const char  *instance_id,
                               GError     **error)
{
  g_autoptr(GDBusConnection) conn = NULL;
  g_autofree char *path = NULL;
  g_autofree char *address = NULL;
  g_autofree char *name = NULL;
  g_autofree char *app_id_escaped = NULL;
  g_autofree char *instance_id_escaped = NULL;
  g_autofree char *job = NULL;
  SystemdManager *manager = NULL;
  GVariantBuilder builder;
  GVariant *properties = NULL;
  GVariant *aux = NULL;
  guint32 pid;
  GMainLoop *main_loop = NULL;
  struct JobData data;
  gboolean res = FALSE;
  g_autoptr(GMainContextPopDefault) main_context = NULL;

  g_return_val_if_fail (app_id != NULL, FALSE);
  g_return_val_if_fail (instance_id != NULL, FALSE);

  path = g_strdup_printf ("/run/user/%d/systemd/private", getuid ());

  if (!g_file_test (path, G_FILE_TEST_EXISTS))
    return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED,
                               _("No systemd user session available, cgroups not available"));

  main_context = flatpak_main_context_new_default ();
  main_loop = g_main_loop_new (main_context, FALSE);

  address = g_strconcat ("unix:path=", path, NULL);

  conn = g_dbus_connection_new_for_address_sync (address,
                                                 G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT,
                                                 NULL,
                                                 NULL, error);
  if (!conn)
    goto out;

  manager = systemd_manager_proxy_new_sync (conn,
                                            G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES,
                                            NULL,
                                            "/org/freedesktop/systemd1",
                                            NULL, error);
  if (!manager)
    goto out;

  app_id_escaped = systemd_unit_name_escape (app_id);
  instance_id_escaped = systemd_unit_name_escape (instance_id);
  name = g_strdup_printf ("app-flatpak-%s-%s.scope",
                          app_id_escaped,
                          instance_id_escaped);

  g_variant_builder_init (&builder, G_VARIANT_TYPE ("a(sv)"));

  pid = getpid ();
  g_variant_builder_add (&builder, "(sv)",
                         "PIDs",
                         g_variant_new_fixed_array (G_VARIANT_TYPE ("u"),
                                                    &pid, 1, sizeof (guint32)));

  properties = g_variant_builder_end (&builder);

  aux = g_variant_new_array (G_VARIANT_TYPE ("(sa(sv))"), NULL, 0);

  if (!systemd_manager_call_start_transient_unit_sync (manager,
                                                       name,
                                                       "fail",
                                                       properties,
                                                       aux,
                                                       &job,
                                                       NULL,
                                                       error))
    goto out;

  data.job = job;
  data.main_loop = main_loop;
  g_signal_connect (manager, "job-removed", G_CALLBACK (job_removed_cb), &data);

  g_main_loop_run (main_loop);

  res = TRUE;

out:
  if (main_loop)
    g_main_loop_unref (main_loop);
  if (manager)
    g_object_unref (manager);

  return res;
}

static void
add_font_path_args (FlatpakBwrap *bwrap)
{
  g_autoptr(GString) xml_snippet = g_string_new ("");
  gchar *path_build_tmp = NULL;
  g_autoptr(GFile) user_font1 = NULL;
  g_autoptr(GFile) user_font2 = NULL;
  g_autoptr(GFile) user_font_cache = NULL;
  g_auto(GStrv) system_cache_dirs = NULL;
  gboolean found_cache = FALSE;
  int i;


  g_string_append (xml_snippet,
                   "<?xml version=\"1.0\"?>\n"
                   "<!DOCTYPE fontconfig SYSTEM \"urn:fontconfig:fonts.dtd\">\n"
                   "<fontconfig>\n");

  if (g_file_test (SYSTEM_FONTS_DIR, G_FILE_TEST_EXISTS))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", SYSTEM_FONTS_DIR, "/run/host/fonts",
                              NULL);
      g_string_append_printf (xml_snippet,
                              "\t<remap-dir as-path=\"%s\">/run/host/fonts</remap-dir>\n",
                              SYSTEM_FONTS_DIR);
    }

  if (g_file_test ("/usr/local/share/fonts", G_FILE_TEST_EXISTS))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", "/usr/local/share/fonts", "/run/host/local-fonts",
                              NULL);
      g_string_append_printf (xml_snippet,
                              "\t<remap-dir as-path=\"%s\">/run/host/local-fonts</remap-dir>\n",
                              "/usr/local/share/fonts");
    }

  system_cache_dirs = g_strsplit (SYSTEM_FONT_CACHE_DIRS, ":", 0);
  for (i = 0; system_cache_dirs[i] != NULL; i++)
    {
      if (g_file_test (system_cache_dirs[i], G_FILE_TEST_EXISTS))
        {
          flatpak_bwrap_add_args (bwrap,
                                  "--ro-bind", system_cache_dirs[i], "/run/host/fonts-cache",
                                  NULL);
          found_cache = TRUE;
          break;
        }
    }

  if (!found_cache)
    {
      /* We ensure these directories are never writable, or fontconfig
         will use them to write the default cache */
      flatpak_bwrap_add_args (bwrap,
                              "--tmpfs", "/run/host/fonts-cache",
                              "--remount-ro", "/run/host/fonts-cache",
                              NULL);
    }

  path_build_tmp = g_build_filename (g_get_user_data_dir (), "fonts", NULL);
  user_font1 = g_file_new_for_path (path_build_tmp);
  g_clear_pointer (&path_build_tmp, g_free);

  path_build_tmp = g_build_filename (g_get_home_dir (), ".fonts", NULL);
  user_font2 = g_file_new_for_path (path_build_tmp);
  g_clear_pointer (&path_build_tmp, g_free);

  if (g_file_query_exists (user_font1, NULL))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", flatpak_file_get_path_cached (user_font1), "/run/host/user-fonts",
                              NULL);
      g_string_append_printf (xml_snippet,
                              "\t<remap-dir as-path=\"%s\">/run/host/user-fonts</remap-dir>\n",
                              flatpak_file_get_path_cached (user_font1));
    }
  else if (g_file_query_exists (user_font2, NULL))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", flatpak_file_get_path_cached (user_font2), "/run/host/user-fonts",
                              NULL);
      g_string_append_printf (xml_snippet,
                              "\t<remap-dir as-path=\"%s\">/run/host/user-fonts</remap-dir>\n",
                              flatpak_file_get_path_cached (user_font2));
    }

  path_build_tmp = g_build_filename (g_get_user_cache_dir (), "fontconfig", NULL);
  user_font_cache = g_file_new_for_path (path_build_tmp);
  g_clear_pointer (&path_build_tmp, g_free);

  if (g_file_query_exists (user_font_cache, NULL))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", flatpak_file_get_path_cached (user_font_cache), "/run/host/user-fonts-cache",
                              NULL);
    }
  else
    {
      /* We ensure these directories are never writable, or fontconfig
         will use them to write the default cache */
      flatpak_bwrap_add_args (bwrap,
                              "--tmpfs", "/run/host/user-fonts-cache",
                              "--remount-ro", "/run/host/user-fonts-cache",
                              NULL);
    }

  g_string_append (xml_snippet,
                   "</fontconfig>\n");

  if (!flatpak_bwrap_add_args_data (bwrap, "font-dirs.xml", xml_snippet->str, xml_snippet->len, "/run/host/font-dirs.xml", NULL))
    g_warning ("Unable to add fontconfig data snippet");
}

static void
add_icon_path_args (FlatpakBwrap *bwrap)
{
  g_autofree gchar *user_icons_path = NULL;
  g_autoptr(GFile) user_icons = NULL;

  if (g_file_test ("/usr/share/icons", G_FILE_TEST_IS_DIR))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", "/usr/share/icons", "/run/host/share/icons",
                              NULL);
    }

  user_icons_path = g_build_filename (g_get_user_data_dir (), "icons", NULL);
  user_icons = g_file_new_for_path (user_icons_path);
  if (g_file_query_exists (user_icons, NULL))
    {
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", flatpak_file_get_path_cached (user_icons), "/run/host/user-share/icons",
                              NULL);
    }
}

FlatpakContext *
flatpak_app_compute_permissions (GKeyFile *app_metadata,
                                 GKeyFile *runtime_metadata,
                                 GError  **error)
{
  g_autoptr(FlatpakContext) app_context = NULL;

  app_context = flatpak_context_new ();

  if (runtime_metadata != NULL)
    {
      if (!flatpak_context_load_metadata (app_context, runtime_metadata, error))
        return NULL;

      /* Don't inherit any permissions from the runtime, only things like env vars. */
      flatpak_context_reset_permissions (app_context);

      flatpak_context_dump (app_context, "Metadata from runtime");
    }

  if (app_metadata != NULL &&
      !flatpak_context_load_metadata (app_context, app_metadata, error))
    return NULL;

  flatpak_context_dump (app_context, "Metadata from app manifest");
  return g_steal_pointer (&app_context);
}

#ifdef HAVE_DCONF

static void
add_dconf_key_to_keyfile (GKeyFile      *keyfile,
                          DConfClient   *client,
                          const char    *key,
                          DConfReadFlags flags)
{
  g_autofree char *group = g_path_get_dirname (key);
  g_autofree char *k = g_path_get_basename (key);
  GVariant *value = dconf_client_read_full (client, key, flags, NULL);

  if (value)
    {
      g_autofree char *val = g_variant_print (value, TRUE);
      g_key_file_set_value (keyfile, group + 1, k, val);
    }
}

static void
add_dconf_dir_to_keyfile (GKeyFile      *keyfile,
                          DConfClient   *client,
                          const char    *dir,
                          DConfReadFlags flags)
{
  g_auto(GStrv) keys = NULL;
  int i;

  keys = dconf_client_list (client, dir, NULL);
  for (i = 0; keys[i]; i++)
    {
      g_autofree char *k = g_strconcat (dir, keys[i], NULL);
      if (dconf_is_dir (k, NULL))
        add_dconf_dir_to_keyfile (keyfile, client, k, flags);
      else if (dconf_is_key (k, NULL))
        add_dconf_key_to_keyfile (keyfile, client, k, flags);
    }
}

static void
add_dconf_locks_to_list (GString     *s,
                         DConfClient *client,
                         const char  *dir)
{
  g_auto(GStrv) locks = NULL;
  int i;

  locks = dconf_client_list_locks (client, dir, NULL);
  for (i = 0; locks[i]; i++)
    {
      g_string_append (s, locks[i]);
      g_string_append_c (s, '\n');
    }
}

#endif /* HAVE_DCONF */

static void
get_dconf_data (const char  *app_id,
                const char **paths,
                const char  *migrate_path,
                char       **defaults,
                gsize       *defaults_size,
                char       **values,
                gsize       *values_size,
                char       **locks,
                gsize       *locks_size)
{
#ifdef HAVE_DCONF
  DConfClient *client = NULL;
  g_autofree char *prefix = NULL;
#endif
  g_autoptr(GKeyFile) defaults_data = NULL;
  g_autoptr(GKeyFile) values_data = NULL;
  g_autoptr(GString) locks_data = NULL;

  defaults_data = g_key_file_new ();
  values_data = g_key_file_new ();
  locks_data = g_string_new ("");

#ifdef HAVE_DCONF

  client = dconf_client_new ();

  prefix = flatpak_dconf_path_for_app_id (app_id);

  if (migrate_path)
    {
      g_info ("Add values in dir '%s', prefix is '%s'", migrate_path, prefix);
      if (flatpak_dconf_path_is_similar (migrate_path, prefix))
        add_dconf_dir_to_keyfile (values_data, client, migrate_path, DCONF_READ_USER_VALUE);
      else
        g_warning ("Ignoring D-Conf migrate-path setting %s", migrate_path);
    }

  g_info ("Add defaults in dir %s", prefix);
  add_dconf_dir_to_keyfile (defaults_data, client, prefix, DCONF_READ_DEFAULT_VALUE);

  g_info ("Add locks in dir %s", prefix);
  add_dconf_locks_to_list (locks_data, client, prefix);

  /* We allow extra paths for defaults and locks, but not for user values */
  if (paths)
    {
      int i;
      for (i = 0; paths[i]; i++)
        {
          if (dconf_is_dir (paths[i], NULL))
            {
              g_info ("Add defaults in dir %s", paths[i]);
              add_dconf_dir_to_keyfile (defaults_data, client, paths[i], DCONF_READ_DEFAULT_VALUE);

              g_info ("Add locks in dir %s", paths[i]);
              add_dconf_locks_to_list (locks_data, client, paths[i]);
            }
          else if (dconf_is_key (paths[i], NULL))
            {
              g_info ("Add individual key %s", paths[i]);
              add_dconf_key_to_keyfile (defaults_data, client, paths[i], DCONF_READ_DEFAULT_VALUE);
              add_dconf_key_to_keyfile (values_data, client, paths[i], DCONF_READ_USER_VALUE);
            }
          else
            {
              g_warning ("Ignoring settings path '%s': neither dir nor key", paths[i]);
            }
        }
    }
#endif

  *defaults = g_key_file_to_data (defaults_data, defaults_size, NULL);
  *values = g_key_file_to_data (values_data, values_size, NULL);
  *locks_size = locks_data->len;
  *locks = g_string_free (g_steal_pointer (&locks_data), FALSE);

#ifdef HAVE_DCONF
  g_object_unref (client);
#endif
}

static gboolean
flatpak_run_add_dconf_args (FlatpakBwrap *bwrap,
                            const char   *app_id,
                            GKeyFile     *metakey,
                            GError      **error)
{
  g_auto(GStrv) paths = NULL;
  g_autofree char *migrate_path = NULL;
  g_autofree char *defaults = NULL;
  g_autofree char *values = NULL;
  g_autofree char *locks = NULL;
  gsize defaults_size;
  gsize values_size;
  gsize locks_size;

  if (metakey)
    {
      paths = g_key_file_get_string_list (metakey,
                                          FLATPAK_METADATA_GROUP_DCONF,
                                          FLATPAK_METADATA_KEY_DCONF_PATHS,
                                          NULL, NULL);
      migrate_path = g_key_file_get_string (metakey,
                                            FLATPAK_METADATA_GROUP_DCONF,
                                            FLATPAK_METADATA_KEY_DCONF_MIGRATE_PATH,
                                            NULL);
    }

  get_dconf_data (app_id,
                  (const char **) paths,
                  migrate_path,
                  &defaults, &defaults_size,
                  &values, &values_size,
                  &locks, &locks_size);

  if (defaults_size != 0 &&
      !flatpak_bwrap_add_args_data (bwrap,
                                    "dconf-defaults",
                                    defaults, defaults_size,
                                    "/etc/glib-2.0/settings/defaults",
                                    error))
    return FALSE;

  if (locks_size != 0 &&
      !flatpak_bwrap_add_args_data (bwrap,
                                    "dconf-locks",
                                    locks, locks_size,
                                    "/etc/glib-2.0/settings/locks",
                                    error))
    return FALSE;

  /* We do a one-time conversion of existing dconf settings to a keyfile.
   * Only do that once the app stops requesting dconf access.
   */
  if (migrate_path)
    {
      g_autofree char *filename = NULL;

      filename = g_build_filename (g_get_home_dir (),
                                   ".var/app", app_id,
                                   "config/glib-2.0/settings/keyfile",
                                   NULL);

      g_info ("writing D-Conf values to %s", filename);

      if (values_size != 0 && !g_file_test (filename, G_FILE_TEST_EXISTS))
        {
          g_autofree char *dir = g_path_get_dirname (filename);

          if (g_mkdir_with_parents (dir, 0700) == -1)
            {
              g_warning ("failed creating dirs for %s", filename);
              return FALSE;
            }

          if (!g_file_set_contents (filename, values, values_size, error))
            {
              g_warning ("failed writing %s", filename);
              return FALSE;
            }
        }
    }

  return TRUE;
}

static gboolean
flatpak_run_save_environ (const char * const  *run_environ,
                          const char          *dir,
                          GCancellable        *cancellable,
                          GError             **error)
{
  g_autoptr(GByteArray) buffer = g_byte_array_new ();
  int i;
  glnx_autofd int dir_fd = -1;

  g_assert (run_environ != NULL);

  for (i = 0; run_environ[i] != NULL; i++)
    {
      gsize size = strlen (run_environ[i]) + 1;

      g_byte_array_append (buffer,
                           (const guint8 *) run_environ[i],
                           size);
    }

  if (!glnx_opendirat (AT_FDCWD, dir, TRUE,
                       &dir_fd,
                       error))
    return FALSE;

  if (!glnx_file_replace_contents_with_perms_at (dir_fd, "run-environ",
                                                 buffer->data, buffer->len,
                                                 (mode_t) 0400,
                                                 (uid_t) -1, (gid_t) -1,
                                                 0,
                                                 cancellable, error))
    return FALSE;

  return TRUE;
}

gboolean
flatpak_run_add_app_info_args (FlatpakBwrap           *bwrap,
                               GFile                  *app_files,
                               GFile                  *original_app_files,
                               GBytes                 *app_deploy_data,
                               const char             *app_extensions,
                               GFile                  *runtime_files,
                               GFile                  *original_runtime_files,
                               GBytes                 *runtime_deploy_data,
                               const char             *runtime_extensions,
                               const char             *app_id,
                               const char             *app_branch,
                               FlatpakDecomposed      *runtime_ref,
                               GFile                  *app_id_dir,
                               FlatpakContext         *final_app_context,
                               FlatpakContext         *cmdline_context,
                               FlatpakContextSockets   sockets,
                               gboolean                sandbox,
                               gboolean                build,
                               gboolean                devel,
                               char                  **app_info_path_out,
                               int                     instance_id_fd_arg,
                               char                  **instance_id_host_dir_out,
                               char                  **instance_id_host_private_dir_out,
                               char                  **instance_id_out,
                               GError                **error)
{
  g_autofree char *info_path = NULL;
  g_autofree char *bwrapinfo_path = NULL;
  glnx_autofd int fd1 = -1;
  glnx_autofd int fd2 = -1;
  glnx_autofd int fd3 = -1;
  int info_fd;
  glnx_autofd int instance_id_fd = instance_id_fd_arg;
  g_autoptr(GKeyFile) keyfile = NULL;
  g_autofree char *runtime_path = NULL;
  const char *group;
  g_autofree char *instance_id = NULL;
  glnx_autofd int lock_fd = -1;
  g_autofree char *instance_id_host_dir = NULL;
  g_autofree char *instance_id_host_private_dir = NULL;
  g_autofree char *instance_id_sandbox_dir = NULL;
  g_autofree char *instance_id_lock_file = NULL;
  g_autofree char *arch = flatpak_decomposed_dup_arch (runtime_ref);

  g_return_val_if_fail (app_id != NULL, FALSE);

  instance_id = flatpak_instance_allocate_id (&instance_id_host_dir,
                                              &instance_id_host_private_dir,
                                              &lock_fd);
  if (instance_id == NULL)
    return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Unable to allocate instance id"));

  instance_id_sandbox_dir = g_strdup_printf ("/run/flatpak/.flatpak/%s", instance_id);
  instance_id_lock_file = g_build_filename (instance_id_sandbox_dir, ".ref", NULL);

  flatpak_bwrap_add_args (bwrap,
                          "--ro-bind",
                          instance_id_host_dir,
                          instance_id_sandbox_dir,
                          "--lock-file",
                          instance_id_lock_file,
                          NULL);
  flatpak_bwrap_add_runtime_dir_member (bwrap, ".flatpak");
  /* Keep the .ref lock held until we've started bwrap to avoid races */
  flatpak_bwrap_add_noinherit_fd (bwrap, g_steal_fd (&lock_fd));

  info_path = g_build_filename (instance_id_host_dir, "info", NULL);

  keyfile = g_key_file_new ();

  if (original_app_files)
    group = FLATPAK_METADATA_GROUP_APPLICATION;
  else
    group = FLATPAK_METADATA_GROUP_RUNTIME;

  g_key_file_set_string (keyfile, group, FLATPAK_METADATA_KEY_NAME, app_id);
  g_key_file_set_string (keyfile, group, FLATPAK_METADATA_KEY_RUNTIME,
                         flatpak_decomposed_get_ref (runtime_ref));

  g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                         FLATPAK_METADATA_KEY_INSTANCE_ID, instance_id);
  if (app_id_dir)
    {
      g_autofree char *instance_path = g_file_get_path (app_id_dir);
      g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                             FLATPAK_METADATA_KEY_INSTANCE_PATH, instance_path);
    }

  if (app_files)
    {
      g_autofree char *app_path = g_file_get_path (app_files);
      g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                             FLATPAK_METADATA_KEY_APP_PATH, app_path);
    }

  if (original_app_files != NULL && original_app_files != app_files)
    {
      g_autofree char *app_path = g_file_get_path (original_app_files);
      g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                             FLATPAK_METADATA_KEY_ORIGINAL_APP_PATH, app_path);
    }

  if (app_deploy_data)
    g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                           FLATPAK_METADATA_KEY_APP_COMMIT, flatpak_deploy_data_get_commit (app_deploy_data));
  if (app_extensions && *app_extensions != 0)
    g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                           FLATPAK_METADATA_KEY_APP_EXTENSIONS, app_extensions);
  runtime_path = g_file_get_path (runtime_files);
  g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                         FLATPAK_METADATA_KEY_RUNTIME_PATH, runtime_path);

  if (runtime_files != original_runtime_files)
    {
      g_autofree char *path = g_file_get_path (original_runtime_files);
      g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                             FLATPAK_METADATA_KEY_ORIGINAL_RUNTIME_PATH, path);
    }

  if (runtime_deploy_data)
    g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                           FLATPAK_METADATA_KEY_RUNTIME_COMMIT, flatpak_deploy_data_get_commit (runtime_deploy_data));
  if (runtime_extensions && *runtime_extensions != 0)
    g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                           FLATPAK_METADATA_KEY_RUNTIME_EXTENSIONS, runtime_extensions);
  if (app_branch != NULL)
    g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                           FLATPAK_METADATA_KEY_BRANCH, app_branch);
  g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                         FLATPAK_METADATA_KEY_ARCH, arch);

  g_key_file_set_string (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                         FLATPAK_METADATA_KEY_FLATPAK_VERSION, PACKAGE_VERSION);

  if ((sockets & FLATPAK_CONTEXT_SOCKET_SESSION_BUS) == 0)
    g_key_file_set_boolean (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                            FLATPAK_METADATA_KEY_SESSION_BUS_PROXY, TRUE);

  if ((sockets & FLATPAK_CONTEXT_SOCKET_SYSTEM_BUS) == 0)
    g_key_file_set_boolean (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                            FLATPAK_METADATA_KEY_SYSTEM_BUS_PROXY, TRUE);

  if (sandbox)
    g_key_file_set_boolean (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                            FLATPAK_METADATA_KEY_SANDBOX, TRUE);
  if (build)
    g_key_file_set_boolean (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                            FLATPAK_METADATA_KEY_BUILD, TRUE);
  if (devel)
    g_key_file_set_boolean (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                            FLATPAK_METADATA_KEY_DEVEL, TRUE);

  if (cmdline_context)
    {
      g_autoptr(GPtrArray) cmdline_args = g_ptr_array_new_with_free_func (g_free);
      flatpak_context_to_args (cmdline_context, cmdline_args);
      if (cmdline_args->len > 0)
        {
          g_key_file_set_string_list (keyfile, FLATPAK_METADATA_GROUP_INSTANCE,
                                      FLATPAK_METADATA_KEY_EXTRA_ARGS,
                                      (const char * const *) cmdline_args->pdata,
                                      cmdline_args->len);
        }
    }

  flatpak_context_save_metadata (final_app_context, TRUE, keyfile);

  if (!g_key_file_save_to_file (keyfile, info_path, error))
    return FALSE;

  /* We want to create a file on /.flatpak-info that the app cannot modify, which
     we do by creating a read-only bind mount. This way one can openat()
     /proc/$pid/root, and if that succeeds use openat via that to find the
     unfakable .flatpak-info file. However, there is a tiny race in that if
     you manage to open /proc/$pid/root, but then the pid dies, then
     every mount but the root is unmounted in the namespace, so the
     .flatpak-info will be empty. We fix this by first creating a real file
     with the real info in, then bind-mounting on top of that, the same info.
     This way even if the bind-mount is unmounted we can find the real data.
   */

  fd1 = info_fd = open (info_path, O_RDONLY);
  if (fd1 == -1)
    {
      int errsv = errno;
      g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                   _("Failed to open flatpak-info file: %s"), g_strerror (errsv));
      return FALSE;
    }

  fd2 = open (info_path, O_RDONLY);
  if (fd2 == -1)
    {
      int errsv = errno;
      g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                   _("Failed to open flatpak-info file: %s"), g_strerror (errsv));
      return FALSE;
    }

  flatpak_bwrap_add_args (bwrap, "--perms", "0600", NULL);
  flatpak_bwrap_add_args_data_fd (bwrap,
                                  "--file", g_steal_fd (&fd1), "/.flatpak-info");
  flatpak_bwrap_add_args_data_fd (bwrap,
                                  "--ro-bind-data", g_steal_fd (&fd2), "/.flatpak-info");

  /* Tell the application that it's running under Flatpak in a generic way. */
  flatpak_bwrap_add_args (bwrap,
                          "--setenv", "container", "flatpak",
                          NULL);
  if (!flatpak_bwrap_add_args_data (bwrap,
                                    "container-manager",
                                    "flatpak\n", -1,
                                    "/run/host/container-manager",
                                    error))
    return FALSE;

  bwrapinfo_path = g_build_filename (instance_id_host_dir, "bwrapinfo.json", NULL);
  fd3 = open (bwrapinfo_path, O_RDWR | O_CREAT, 0644);
  if (fd3 == -1)
    {
      int errsv = errno;
      g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                   _("Failed to open bwrapinfo.json file: %s"), g_strerror (errsv));
      return FALSE;
    }

  /* NOTE: It is important that this takes place after bwrapinfo.json is created,
     otherwise start notifications in the portal may not work. */
  if (instance_id_fd != -1)
    {
      gsize instance_id_position = 0;
      gsize instance_id_size = strlen (instance_id);

      while (instance_id_size > 0)
        {
          gssize bytes_written = write (instance_id_fd, instance_id + instance_id_position, instance_id_size);
          if (G_UNLIKELY (bytes_written <= 0))
            {
              int errsv = bytes_written == -1 ? errno : ENOSPC;
              if (errsv == EINTR)
                continue;

              g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
                           _("Failed to write to instance id fd: %s"), g_strerror (errsv));
              return FALSE;
            }

          instance_id_position += bytes_written;
          instance_id_size -= bytes_written;
        }

      /* explicitly close this as soon as we're done to notify the other side */
      g_clear_fd (&instance_id_fd, NULL);
    }

  flatpak_bwrap_add_args_data_fd (bwrap, "--info-fd", g_steal_fd (&fd3), NULL);

  if (app_info_path_out != NULL)
    *app_info_path_out = g_strdup_printf ("/proc/self/fd/%d", info_fd);

  if (instance_id_host_dir_out != NULL)
    *instance_id_host_dir_out = g_steal_pointer (&instance_id_host_dir);

  if (instance_id_host_private_dir_out != NULL)
    *instance_id_host_private_dir_out = g_steal_pointer (&instance_id_host_private_dir);

  if (instance_id_out != NULL)
    *instance_id_out = g_steal_pointer (&instance_id);

  return TRUE;
}

/*
 * @runtime_fd: the /usr for the runtime, or -1 if running with no runtime,
 *  perhaps to unpack extra-data
 */
static void
add_tzdata_args (FlatpakBwrap *bwrap,
                 int           runtime_fd)
{
  g_autofree char *raw_timezone = NULL;
  g_autofree char *timezone_content = NULL;
  g_autofree char *localtime_content = NULL;
  const char *tzdir;
  glnx_autofd int tzdir_fd = -1;
  glnx_autofd int zoneinfo_fd = -1;
  g_autoptr(GError) error = NULL;

  g_return_if_fail (runtime_fd >= -1);

  raw_timezone = flatpak_get_timezone ();
  timezone_content = g_strdup_printf ("%s\n", raw_timezone);
  localtime_content = g_strconcat ("../usr/share/zoneinfo/", raw_timezone, NULL);

  tzdir = flatpak_get_tzdir ();

  tzdir_fd = glnx_chaseat (AT_FDCWD, tzdir, GLNX_CHASE_MUST_BE_DIRECTORY, NULL);

  if (runtime_fd >= 0)
    zoneinfo_fd = glnx_chaseat (runtime_fd, "share/zoneinfo",
                                GLNX_CHASE_RESOLVE_BENEATH |
                                GLNX_CHASE_MUST_BE_DIRECTORY,
                                NULL);

  /* Check for host /usr/share/zoneinfo */
  if (tzdir_fd >= 0 && zoneinfo_fd >= 0)
    {
      /* Here we assume the host timezone file exist in the host data */
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", tzdir, "/usr/share/zoneinfo",
                              "--symlink", localtime_content, "/etc/localtime",
                              NULL);
    }
  else if (runtime_fd >= 0)
    {
      g_autofree char *runtime_zoneinfo = NULL;
      glnx_autofd int runtime_zoneinfo_fd = -1;

      runtime_zoneinfo = g_strconcat ("share/zoneinfo/", raw_timezone, NULL);

      /* Check for runtime /usr/share/zoneinfo */
      runtime_zoneinfo_fd = glnx_chaseat (runtime_fd, runtime_zoneinfo,
                                          GLNX_CHASE_RESOLVE_BENEATH |
                                          GLNX_CHASE_MUST_BE_REGULAR,
                                          NULL);
      if (runtime_zoneinfo_fd >= 0)
        {
          flatpak_bwrap_add_args (bwrap,
                                  "--symlink", localtime_content, "/etc/localtime",
                                  NULL);
        }
    }

  flatpak_bwrap_add_args_data (bwrap, "timezone",
                               timezone_content, -1, "/etc/timezone",
                               NULL);
}

static void
add_monitor_path_args (gboolean      use_session_helper,
                       FlatpakBwrap *bwrap)
{
  g_autoptr(AutoFlatpakSessionHelper) session_helper = NULL;
  g_autofree char *monitor_path = NULL;
  g_autofree char *pkcs11_socket_path = NULL;
  g_autoptr(GVariant) session_data = NULL;

  if (use_session_helper)
    {
      session_helper =
        flatpak_session_helper_proxy_new_for_bus_sync (G_BUS_TYPE_SESSION,
                                                       G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES | G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS,
                                                       FLATPAK_SESSION_HELPER_BUS_NAME,
                                                       FLATPAK_SESSION_HELPER_PATH,
                                                       NULL, NULL);
    }

  if (session_helper &&
      flatpak_session_helper_call_request_session_sync (session_helper,
                                                        &session_data,
                                                        NULL, NULL))
    {
      if (g_variant_lookup (session_data, "path", "s", &monitor_path))
        flatpak_bwrap_add_args (bwrap,
                                "--ro-bind", monitor_path, "/run/host/monitor",
                                "--symlink", "/run/host/monitor/resolv.conf", "/etc/resolv.conf",
                                "--symlink", "/run/host/monitor/host.conf", "/etc/host.conf",
                                "--symlink", "/run/host/monitor/hosts", "/etc/hosts",
                                "--symlink", "/run/host/monitor/gai.conf", "/etc/gai.conf",
                                NULL);

      if (g_variant_lookup (session_data, "pkcs11-socket", "s", &pkcs11_socket_path))
        {
          static const char sandbox_pkcs11_socket_path[] = "/run/flatpak/p11-kit/pkcs11";
          const char *trusted_module_contents =
            "# This overrides the runtime p11-kit-trusted module with a client one talking to the trust module on the host\n"
            "module: p11-kit-client.so\n";

          if (flatpak_bwrap_add_args_data (bwrap, "p11-kit-trust.module",
                                           trusted_module_contents, -1,
                                           "/etc/pkcs11/modules/p11-kit-trust.module", NULL))
            {
              flatpak_bwrap_add_args (bwrap,
                                      "--ro-bind", pkcs11_socket_path, sandbox_pkcs11_socket_path,
                                      NULL);
              flatpak_bwrap_unset_env (bwrap, "P11_KIT_SERVER_ADDRESS");
              flatpak_bwrap_add_runtime_dir_member (bwrap, "p11-kit");
            }
        }
    }
  else
    {
      if (g_file_test ("/etc/resolv.conf", G_FILE_TEST_EXISTS))
        flatpak_bwrap_add_args (bwrap,
                                "--ro-bind", "/etc/resolv.conf", "/etc/resolv.conf",
                                NULL);
      if (g_file_test ("/etc/host.conf", G_FILE_TEST_EXISTS))
        flatpak_bwrap_add_args (bwrap,
                                "--ro-bind", "/etc/host.conf", "/etc/host.conf",
                                NULL);
      if (g_file_test ("/etc/hosts", G_FILE_TEST_EXISTS))
        flatpak_bwrap_add_args (bwrap,
                                "--ro-bind", "/etc/hosts", "/etc/hosts",
                                NULL);
      if (g_file_test ("/etc/gai.conf", G_FILE_TEST_EXISTS))
        flatpak_bwrap_add_args (bwrap,
                                "--ro-bind", "/etc/gai.conf", "/etc/gai.conf",
                                NULL);
    }
}

static void
add_document_portal_args (FlatpakBwrap *bwrap,
                          const char   *app_id,
                          char        **out_mount_path)
{
  g_autoptr(GDBusConnection) session_bus = NULL;
  g_autofree char *doc_mount_path = NULL;

  session_bus = g_bus_get_sync (G_BUS_TYPE_SESSION, NULL, NULL);
  if (session_bus)
    {
      g_autoptr(GError) local_error = NULL;
      g_autoptr(GDBusMessage) reply = NULL;
      g_autoptr(GDBusMessage) msg =
        g_dbus_message_new_method_call ("org.freedesktop.portal.Documents",
                                        "/org/freedesktop/portal/documents",
                                        "org.freedesktop.portal.Documents",
                                        "GetMountPoint");
      g_dbus_message_set_body (msg, g_variant_new ("()"));
      reply =
        g_dbus_connection_send_message_with_reply_sync (session_bus, msg,
                                                        G_DBUS_SEND_MESSAGE_FLAGS_NONE,
                                                        30000,
                                                        NULL,
                                                        NULL,
                                                        NULL);
      if (reply)
        {
          if (g_dbus_message_to_gerror (reply, &local_error))
            {
              if (g_error_matches (local_error, G_DBUS_ERROR, G_DBUS_ERROR_SERVICE_UNKNOWN))
                g_info ("Document portal not available, not mounting /run/flatpak/doc");
              else
                g_message ("Can't get document portal: %s", local_error->message);
            }
          else
            {
              static const char dst_path[] = "/run/flatpak/doc";
              g_autofree char *src_path = NULL;
              g_variant_get (g_dbus_message_get_body (reply),
                             "(^ay)", &doc_mount_path);

              src_path = g_strdup_printf ("%s/by-app/%s",
                                          doc_mount_path, app_id);
              flatpak_bwrap_add_args (bwrap, "--bind", src_path, dst_path, NULL);
              flatpak_bwrap_add_runtime_dir_member (bwrap, "doc");
            }
        }
    }

  *out_mount_path = g_steal_pointer (&doc_mount_path);
}

#ifdef ENABLE_SECCOMP
static const uint32_t seccomp_x86_64_extra_arches[] = { SCMP_ARCH_X86, 0, };

#ifdef SCMP_ARCH_AARCH64
static const uint32_t seccomp_aarch64_extra_arches[] = { SCMP_ARCH_ARM, 0 };
#endif

/*
 * @negative_errno: Result code as returned by libseccomp functions
 *
 * Translate a libseccomp error code into an error message. libseccomp
 * mostly returns negative `errno` values such as `-ENOMEM`, but some
 * standard `errno` values are used for non-standard purposes where their
 * `strerror()` would be misleading.
 *
 * Returns: a string version of @negative_errno if possible
 */
static const char *
flatpak_seccomp_strerror (int negative_errno)
{
  g_return_val_if_fail (negative_errno < 0, "Non-negative error value from libseccomp?");
  g_return_val_if_fail (negative_errno > INT_MIN, "Out of range error value from libseccomp?");

  switch (negative_errno)
    {
      case -EDOM:
        return "Architecture specific failure";

      case -EFAULT:
        return "Internal libseccomp failure (unknown syscall?)";

      case -ECANCELED:
        return "System failure beyond the control of libseccomp";
    }

  /* e.g. -ENOMEM: the result of strerror() is good enough */
  return g_strerror (-negative_errno);
}

static inline void
cleanup_seccomp (void *p)
{
  scmp_filter_ctx *pp = (scmp_filter_ctx *) p;

  if (*pp)
    seccomp_release (*pp);
}

static gboolean
setup_seccomp (FlatpakBwrap   *bwrap,
               const char     *arch,
               gulong          allowed_personality,
               FlatpakRunFlags run_flags,
               GError        **error)
{
  gboolean multiarch = (run_flags & FLATPAK_RUN_FLAG_MULTIARCH) != 0;
  gboolean devel = (run_flags & FLATPAK_RUN_FLAG_DEVEL) != 0;

  __attribute__((cleanup (cleanup_seccomp))) scmp_filter_ctx seccomp = NULL;

  /**** BEGIN NOTE ON CODE SHARING
   *
   * This code was originally part of the obsolete linux-user-chroot project,
   * which was itself heavily influenced by Sandstorm's seccomp filters.
   * Nowadays, the canonical upstream location for this code is Flatpak:
   *
   *   https://github.com/flatpak/flatpak/blob/main/common/flatpak-run.c
   *
   * Here is a list of projects that have directly copied Flatpak's sandbox
   * filters. These projects aim to exactly or almost exactly match what Flatpak
   * is doing, so we almost always need to update them whenever the code here is
   * touched:
   *
   *   https://github.com/WebKit/WebKit/blob/main/Source/WebKit/UIProcess/Launcher/glib/BubblewrapLauncher.cpp
   *   https://gitlab.gnome.org/GNOME/gnome-desktop/-/blob/master/libgnome-desktop/gnome-desktop-thumbnail-script.c
   *
   * (We perhaps ought to split this code out of Flatpak into a subproject, to
   * make code sharing easier and reduce the need for manual copy/pasting.)
   *
   **** END NOTE ON CODE SHARING
   */
  struct
  {
    int                  scall;
    int                  errnum;
    struct scmp_arg_cmp *arg;
  } syscall_blocklist[] = {
    /* Block dmesg */
    {SCMP_SYS (syslog), EPERM},
    /* Useless old syscall */
    {SCMP_SYS (uselib), EPERM},
    /* Don't allow disabling accounting */
    {SCMP_SYS (acct), EPERM},
    /* Don't allow reading current quota use */
    {SCMP_SYS (quotactl), EPERM},

    /* Don't allow access to the kernel keyring */
    {SCMP_SYS (add_key), EPERM},
    {SCMP_SYS (keyctl), EPERM},
    {SCMP_SYS (request_key), EPERM},

    /* Scary VM/NUMA ops */
    {SCMP_SYS (move_pages), EPERM},
    {SCMP_SYS (mbind), EPERM},
    {SCMP_SYS (get_mempolicy), EPERM},
    {SCMP_SYS (set_mempolicy), EPERM},
    {SCMP_SYS (migrate_pages), EPERM},

    /* Don't allow subnamespace setups: */
    {SCMP_SYS (unshare), EPERM},
    {SCMP_SYS (setns), EPERM},
    {SCMP_SYS (mount), EPERM},
    {SCMP_SYS (umount), EPERM},
    {SCMP_SYS (umount2), EPERM},
    {SCMP_SYS (pivot_root), EPERM},
    {SCMP_SYS (chroot), EPERM},
#if defined(__s390__) || defined(__s390x__) || defined(__CRIS__)
    /* Architectures with CONFIG_CLONE_BACKWARDS2: the child stack
     * and flags arguments are reversed so the flags come second */
    {SCMP_SYS (clone), EPERM, &SCMP_A1 (SCMP_CMP_MASKED_EQ, CLONE_NEWUSER, CLONE_NEWUSER)},
#else
    /* Normally the flags come first */
    {SCMP_SYS (clone), EPERM, &SCMP_A0 (SCMP_CMP_MASKED_EQ, CLONE_NEWUSER, CLONE_NEWUSER)},
#endif

    /* Don't allow faking input to the controlling tty (CVE-2017-5226) */
    {SCMP_SYS (ioctl), EPERM, &SCMP_A1 (SCMP_CMP_MASKED_EQ, 0xFFFFFFFFu, (int) TIOCSTI)},
    /* In the unlikely event that the controlling tty is a Linux virtual
     * console (/dev/tty2 or similar), copy/paste operations have an effect
     * similar to TIOCSTI (CVE-2023-28100) */
    {SCMP_SYS (ioctl), EPERM, &SCMP_A1 (SCMP_CMP_MASKED_EQ, 0xFFFFFFFFu, (int) TIOCLINUX)},

    /* seccomp can't look into clone3()'s struct clone_args to check whether
     * the flags are OK, so we have no choice but to block clone3().
     * Return ENOSYS so user-space will fall back to clone().
     * (CVE-2021-41133; see also https://github.com/moby/moby/commit/9f6b562d) */
    {SCMP_SYS (clone3), ENOSYS},

    /* New mount manipulation APIs can also change our VFS. There's no
     * legitimate reason to do these in the sandbox, so block all of them
     * rather than thinking about which ones might be dangerous.
     * (CVE-2021-41133) */
    {SCMP_SYS (open_tree), ENOSYS},
    {SCMP_SYS (move_mount), ENOSYS},
    {SCMP_SYS (fsopen), ENOSYS},
    {SCMP_SYS (fsconfig), ENOSYS},
    {SCMP_SYS (fsmount), ENOSYS},
    {SCMP_SYS (fspick), ENOSYS},
    {SCMP_SYS (mount_setattr), ENOSYS},
  };

  struct
  {
    int                  scall;
    int                  errnum;
    struct scmp_arg_cmp *arg;
  } syscall_nondevel_blocklist[] = {
    /* Profiling operations; we expect these to be done by tools from outside
     * the sandbox.  In particular perf has been the source of many CVEs.
     */
    {SCMP_SYS (perf_event_open), EPERM},
    /* Don't allow you to switch to bsd emulation or whatnot */
    {SCMP_SYS (personality), EPERM, &SCMP_A0 (SCMP_CMP_NE, allowed_personality)},
    {SCMP_SYS (ptrace), EPERM}
  };
  /* Blocklist all but unix, inet, inet6 and netlink */
  struct
  {
    int             family;
    FlatpakRunFlags flags_mask;
  } socket_family_allowlist[] = {
    /* NOTE: Keep in numerical order */
    { AF_UNSPEC, 0 },
    { AF_LOCAL, 0 },
    { AF_INET, 0 },
    { AF_INET6, 0 },
    { AF_NETLINK, 0 },
    { AF_CAN, FLATPAK_RUN_FLAG_CANBUS },
    { AF_BLUETOOTH, FLATPAK_RUN_FLAG_BLUETOOTH },
  };
  int last_allowed_family;
  int i, r;
  g_auto(GLnxTmpfile) seccomp_tmpf  = { 0, };

  seccomp = seccomp_init (SCMP_ACT_ALLOW);
  if (!seccomp)
    return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Initialize seccomp failed"));

  if (arch != NULL)
    {
      uint32_t arch_id = 0;
      const uint32_t *extra_arches = NULL;

      if (strcmp (arch, "i386") == 0)
        {
          arch_id = SCMP_ARCH_X86;
        }
      else if (strcmp (arch, "x86_64") == 0)
        {
          arch_id = SCMP_ARCH_X86_64;
          extra_arches = seccomp_x86_64_extra_arches;
        }
      else if (strcmp (arch, "arm") == 0)
        {
          arch_id = SCMP_ARCH_ARM;
        }
#ifdef SCMP_ARCH_AARCH64
      else if (strcmp (arch, "aarch64") == 0)
        {
          arch_id = SCMP_ARCH_AARCH64;
          extra_arches = seccomp_aarch64_extra_arches;
        }
#endif

      /* We only really need to handle arches on multiarch systems.
       * If only one arch is supported the default is fine */
      if (arch_id != 0)
        {
          /* This *adds* the target arch, instead of replacing the
             native one. This is not ideal, because we'd like to only
             allow the target arch, but we can't really disallow the
             native arch at this point, because then bubblewrap
             couldn't continue running. */
          r = seccomp_arch_add (seccomp, arch_id);
          if (r < 0 && r != -EEXIST)
            return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to add architecture to seccomp filter: %s"), flatpak_seccomp_strerror (r));

          if (multiarch && extra_arches != NULL)
            {
              for (i = 0; extra_arches[i] != 0; i++)
                {
                  r = seccomp_arch_add (seccomp, extra_arches[i]);
                  if (r < 0 && r != -EEXIST)
                    return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to add multiarch architecture to seccomp filter: %s"), flatpak_seccomp_strerror (r));
                }
            }
        }
    }

  /* TODO: Should we filter the kernel keyring syscalls in some way?
   * We do want them to be used by desktop apps, but they could also perhaps
   * leak system stuff or secrets from other apps.
   */

  for (i = 0; i < G_N_ELEMENTS (syscall_blocklist); i++)
    {
      int scall = syscall_blocklist[i].scall;
      int errnum = syscall_blocklist[i].errnum;

      g_return_val_if_fail (errnum == EPERM || errnum == ENOSYS, FALSE);

      if (syscall_blocklist[i].arg)
        r = seccomp_rule_add (seccomp, SCMP_ACT_ERRNO (errnum), scall, 1, *syscall_blocklist[i].arg);
      else
        r = seccomp_rule_add (seccomp, SCMP_ACT_ERRNO (errnum), scall, 0);

      /* EFAULT means "internal libseccomp error", but in practice we get
       * this for syscall numbers added via flatpak-syscalls-private.h
       * when trying to filter them on a non-native architecture, because
       * libseccomp cannot map the syscall number to a name and back to a
       * number for the non-native architecture. */
      if (r == -EFAULT)
        g_debug ("Unable to block syscall %d: syscall not known to libseccomp?",
                 scall);
      else if (r < 0)
        return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to block syscall %d: %s"), scall, flatpak_seccomp_strerror (r));
    }

  if (!multiarch)
    {
      /* modify_ldt is a historic source of interesting information leaks,
       * so it's disabled as a hardening measure.
       * However, it is required to run old 16-bit applications
       * as well as some Wine patches, so it's allowed in multiarch. */
      int scall = SCMP_SYS (modify_ldt);
      r = seccomp_rule_add (seccomp, SCMP_ACT_ERRNO (EPERM), scall, 0);

      /* See above for the meaning of EFAULT. */
      if (r == -EFAULT)
        g_debug ("Unable to block syscall %d: syscall not known to libseccomp?",
                 scall);
      else if (r < 0)
        return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to block syscall %d: %s"), scall, flatpak_seccomp_strerror (r));
    }

  if (!devel)
    {
      for (i = 0; i < G_N_ELEMENTS (syscall_nondevel_blocklist); i++)
        {
          int scall = syscall_nondevel_blocklist[i].scall;
          int errnum = syscall_nondevel_blocklist[i].errnum;

          g_return_val_if_fail (errnum == EPERM || errnum == ENOSYS, FALSE);

          if (syscall_nondevel_blocklist[i].arg)
            r = seccomp_rule_add (seccomp, SCMP_ACT_ERRNO (errnum), scall, 1, *syscall_nondevel_blocklist[i].arg);
          else
            r = seccomp_rule_add (seccomp, SCMP_ACT_ERRNO (errnum), scall, 0);

          /* See above for the meaning of EFAULT. */
          if (r == -EFAULT)
            g_debug ("Unable to block syscall %d: syscall not known to libseccomp?",
                     scall);
          else if (r < 0)
            return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to block syscall %d: %s"), scall, flatpak_seccomp_strerror (r));
        }
    }

  /* Socket filtering doesn't work on e.g. i386, so ignore failures here
   * However, we need to user seccomp_rule_add_exact to avoid libseccomp doing
   * something else: https://github.com/seccomp/libseccomp/issues/8 */
  last_allowed_family = -1;
  for (i = 0; i < G_N_ELEMENTS (socket_family_allowlist); i++)
    {
      int family = socket_family_allowlist[i].family;
      int disallowed;

      if (socket_family_allowlist[i].flags_mask != 0 &&
          (socket_family_allowlist[i].flags_mask & run_flags) != socket_family_allowlist[i].flags_mask)
        continue;

      for (disallowed = last_allowed_family + 1; disallowed < family; disallowed++)
        {
          /* Blocklist the in-between valid families */
          seccomp_rule_add_exact (seccomp, SCMP_ACT_ERRNO (EAFNOSUPPORT), SCMP_SYS (socket), 1, SCMP_A0 (SCMP_CMP_EQ, disallowed));
        }
      last_allowed_family = family;
    }
  /* Blocklist the rest */
  seccomp_rule_add_exact (seccomp, SCMP_ACT_ERRNO (EAFNOSUPPORT), SCMP_SYS (socket), 1, SCMP_A0 (SCMP_CMP_GE, last_allowed_family + 1));

  if (!glnx_open_anonymous_tmpfile_full (O_RDWR | O_CLOEXEC, "/tmp", &seccomp_tmpf, error))
    return FALSE;

  r = seccomp_export_bpf (seccomp, seccomp_tmpf.fd);

  if (r != 0)
    return flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Failed to export bpf: %s"), flatpak_seccomp_strerror (r));

  lseek (seccomp_tmpf.fd, 0, SEEK_SET);

  flatpak_bwrap_add_args_data_fd (bwrap,
                                  "--seccomp", g_steal_fd (&seccomp_tmpf.fd), NULL);

  return TRUE;
}
#endif

/*
 * @runtime_fd: the /usr for the runtime, or -1 if running with no runtime,
 *  perhaps to unpack extra-data
 */
static void
flatpak_run_setup_usr_links (FlatpakBwrap *bwrap,
                             int          runtime_fd,
                             const char   *sysroot)
{
  int i;

  g_return_if_fail (runtime_fd >= -1);

  if (runtime_fd < 0)
    return;

  for (i = 0; flatpak_abs_usrmerged_dirs[i] != NULL; i++)
    {
      const char *subdir = flatpak_abs_usrmerged_dirs[i];
      glnx_autofd int runtime_subdir_fd = -1;
      g_autoptr(GError) local_error = NULL;

      g_assert (subdir[0] == '/');

      /* Skip the '/' when using as a subdirectory of the runtime */
      runtime_subdir_fd = glnx_chaseat (runtime_fd, subdir + 1,
                                        GLNX_CHASE_RESOLVE_BENEATH |
                                        GLNX_CHASE_NOFOLLOW,
                                        &local_error);

      if (runtime_subdir_fd < 0 &&
          !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
        {
          g_warning ("Checking for usrmerged dir %s failed: %s",
                     subdir, local_error->message);
        }
      else if (runtime_subdir_fd < 0)
        {
          g_info ("%s does not exist in runtime", subdir);
        }
      else
        {
          g_autofree char *link = g_strconcat ("usr", subdir, NULL);
          g_autofree char *create = NULL;

          if (sysroot != NULL)
            create = g_strconcat (sysroot, subdir, NULL);
          else
            create = g_strdup (subdir);

          flatpak_bwrap_add_args (bwrap,
                                  "--symlink", link, create,
                                  NULL);
        }
    }
}

/* Directories in /sys to share with the sandbox if accessible. */
static const char *const sysfs_dirs[] =
{
  "/sys/block",
  "/sys/bus",
  "/sys/class",
  "/sys/dev",
  "/sys/devices"
};

/*
 * @runtime_fd: the /usr for the runtime, or -1 if running with no runtime,
 *  perhaps to unpack extra-data
 */
gboolean
flatpak_run_setup_base_argv (FlatpakBwrap   *bwrap,
                             int             runtime_fd,
                             GFile          *app_id_dir,
                             const char     *arch,
                             FlatpakRunFlags flags,
                             GError        **error)
{
  g_autofree char *run_dir = NULL;
  g_autofree char *passwd_contents = NULL;
  g_autoptr(GString) group_contents = NULL;
  const char *pkcs11_conf_contents = NULL;
  struct group *g;
  gulong pers;
  gid_t gid = getgid ();
  gboolean parent_expose_pids = (flags & FLATPAK_RUN_FLAG_PARENT_EXPOSE_PIDS) != 0;
  gboolean parent_share_pids = (flags & FLATPAK_RUN_FLAG_PARENT_SHARE_PIDS) != 0;
  gboolean bwrap_unprivileged = flatpak_bwrap_is_unprivileged ();
  gsize i;

  g_return_val_if_fail (runtime_fd >= -1, FALSE);

  /* Disable recursive userns for all flatpak processes, as we need this
   * to guarantee that the sandbox can't restructure the filesystem.
   * Allowing to change e.g. /.flatpak-info would allow sandbox escape
   * via portals.
   *
   * This is also done via seccomp, but here we do it using userns
   * unsharing in combination with max_user_namespaces.
   *
   * If bwrap is setuid, then --disable-userns will not work, which
   * makes the seccomp filter security-critical.
   */
  if (bwrap_unprivileged)
    {
      if (parent_expose_pids || parent_share_pids)
        {
          /* If we're joining an existing sandbox's user and process
           * namespaces, then it should already have creation of
           * nested user namespaces disabled. */
          flatpak_bwrap_add_arg (bwrap, "--assert-userns-disabled");
        }
      else
        {
          /* This is a new sandbox, so we need to disable creation of
           * nested user namespaces. */
          flatpak_bwrap_add_arg (bwrap, "--unshare-user");
          flatpak_bwrap_add_arg (bwrap, "--disable-userns");
        }
    }

  run_dir = g_strdup_printf ("/run/user/%d", getuid ());

  passwd_contents = g_strdup_printf ("%s:x:%d:%d:%s:%s:%s\n"
                                     "nfsnobody:x:65534:65534:Unmapped user:/:/sbin/nologin\n",
                                     g_get_user_name (),
                                     getuid (), gid,
                                     g_get_real_name (),
                                     g_get_home_dir (),
                                     DEFAULT_SHELL);

  group_contents = g_string_new ("");
  g = getgrgid (gid);
  /* if NULL, the primary group is not known outside the container, so
   * it might as well stay unknown inside the container... */
  if (g != NULL)
    g_string_append_printf (group_contents, "%s:x:%d:%s\n",
                            g->gr_name, gid, g_get_user_name ());
  g_string_append (group_contents, "nfsnobody:x:65534:\n");

  pkcs11_conf_contents =
    "# Disable user pkcs11 config, because the host modules don't work in the runtime\n"
    "user-config: none\n";

  if ((flags & FLATPAK_RUN_FLAG_NO_PROC) == 0)
    flatpak_bwrap_add_args (bwrap,
                            "--proc", "/proc",
                            NULL);

  if (!(flags & FLATPAK_RUN_FLAG_PARENT_SHARE_PIDS))
    flatpak_bwrap_add_arg (bwrap, "--unshare-pid");

  flatpak_bwrap_add_args (bwrap,
                          "--dir", "/tmp",
                          "--dir", "/var/tmp",
                          "--dir", "/run/host",
                          "--perms", "0700", "--dir", run_dir,
                          "--setenv", "XDG_RUNTIME_DIR", run_dir,
                          "--symlink", "../run", "/var/run",
                          "--ro-bind-try", "/proc/self/ns/user", "/run/.userns",
                          /* glib uses this like /etc/timezone */
                          "--symlink", "/etc/timezone", "/var/db/zoneinfo",
                          NULL);

  for (i = 0; i < G_N_ELEMENTS (sysfs_dirs); i++)
    {
      const char *dir = sysfs_dirs[i];

      if (access (dir, R_OK|X_OK) == 0)
        flatpak_bwrap_add_args (bwrap, "--ro-bind", dir, dir, NULL);
      else
        g_info ("Not sharing %s with sandbox: %s", dir, g_strerror (errno));
    }

  if (flags & FLATPAK_RUN_FLAG_DIE_WITH_PARENT)
    flatpak_bwrap_add_args (bwrap,
                            "--die-with-parent",
                            NULL);

  if (flags & FLATPAK_RUN_FLAG_WRITABLE_ETC)
    flatpak_bwrap_add_args (bwrap,
                            "--dir", "/usr/etc",
                            "--symlink", "usr/etc", "/etc",
                            NULL);

  if (!flatpak_bwrap_add_args_data (bwrap, "passwd", passwd_contents, -1, "/etc/passwd", error))
    return FALSE;

  if (!flatpak_bwrap_add_args_data (bwrap, "group", group_contents->str, -1, "/etc/group", error))
    return FALSE;

  if (!flatpak_bwrap_add_args_data (bwrap, "pkcs11.conf", pkcs11_conf_contents, -1, "/etc/pkcs11/pkcs11.conf", error))
    return FALSE;

  if (g_file_test ("/etc/machine-id", G_FILE_TEST_EXISTS))
    flatpak_bwrap_add_args (bwrap, "--ro-bind", "/etc/machine-id", "/etc/machine-id", NULL);
  else if (g_file_test ("/var/lib/dbus/machine-id", G_FILE_TEST_EXISTS))
    flatpak_bwrap_add_args (bwrap, "--ro-bind", "/var/lib/dbus/machine-id", "/etc/machine-id", NULL);

  if (runtime_fd >= 0
      && (flags & FLATPAK_RUN_FLAG_WRITABLE_ETC) == 0)
    {
      g_auto(GLnxDirFdIterator) dfd_iter = { 0, };
      struct dirent *dent;
      gboolean inited;
      g_autoptr(GError) local_error = NULL;

      inited = glnx_dirfd_iterator_init_at (runtime_fd, "etc", FALSE, &dfd_iter, &local_error);
      if (!inited && !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
        {
          g_propagate_error (error, g_steal_pointer (&local_error));
          return FALSE;
        }

      while (inited)
        {
          g_autofree char *dest = NULL;
          glnx_autofd int src_fd = -1;
          struct stat statbuf;

          if (!glnx_dirfd_iterator_next_dent_ensure_dtype (&dfd_iter, &dent, NULL, NULL) || dent == NULL)
            break;

          if (strcmp (dent->d_name, "passwd") == 0 ||
              strcmp (dent->d_name, "group") == 0 ||
              strcmp (dent->d_name, "machine-id") == 0 ||
              strcmp (dent->d_name, "resolv.conf") == 0 ||
              strcmp (dent->d_name, "host.conf") == 0 ||
              strcmp (dent->d_name, "hosts") == 0 ||
              strcmp (dent->d_name, "gai.conf") == 0 ||
              strcmp (dent->d_name, "localtime") == 0 ||
              strcmp (dent->d_name, "timezone") == 0 ||
              strcmp (dent->d_name, "pkcs11") == 0)
            continue;

          dest = g_build_filename ("/etc", dent->d_name, NULL);

          src_fd = glnx_chaseat (dfd_iter.fd, dent->d_name,
                                 GLNX_CHASE_NOFOLLOW |
                                 GLNX_CHASE_RESOLVE_BENEATH,
                                 error);
          if (src_fd < 0)
            return FALSE;

          if (!glnx_fstat (src_fd, &statbuf, error))
            return FALSE;

          if (S_ISLNK (statbuf.st_mode))
            {
              g_autofree char *target = NULL;

              target = glnx_readlinkat_malloc (dfd_iter.fd, dent->d_name,
                                               NULL, error);
              if (target == NULL)
                return FALSE;

              flatpak_bwrap_add_args (bwrap, "--symlink", target, dest, NULL);
            }
          else if (src_fd >= 0)
            {
              flatpak_bwrap_add_args_data_fd (bwrap,
                                              "--ro-bind-fd",
                                              g_steal_fd (&src_fd),
                                              dest);
            }
        }
    }

  if (app_id_dir != NULL)
    {
      g_autoptr(GFile) app_cache_dir = g_file_get_child (app_id_dir, "cache");
      g_autoptr(GFile) app_tmp_dir = g_file_get_child (app_cache_dir, "tmp");
      g_autoptr(GFile) app_data_dir = g_file_get_child (app_id_dir, "data");
      g_autoptr(GFile) app_config_dir = g_file_get_child (app_id_dir, "config");

      flatpak_bwrap_add_args (bwrap,
                              /* These are nice to have as a fixed path */
                              "--bind", flatpak_file_get_path_cached (app_cache_dir), "/var/cache",
                              "--bind", flatpak_file_get_path_cached (app_data_dir), "/var/data",
                              "--bind", flatpak_file_get_path_cached (app_config_dir), "/var/config",
                              "--bind", flatpak_file_get_path_cached (app_tmp_dir), "/var/tmp",
                              NULL);
    }

  flatpak_run_setup_usr_links (bwrap, runtime_fd, NULL);

  add_tzdata_args (bwrap, runtime_fd);

  pers = PER_LINUX;

  if ((flags & FLATPAK_RUN_FLAG_SET_PERSONALITY) &&
      flatpak_is_linux32_arch (arch))
    {
      g_info ("Setting personality linux32");
      pers = PER_LINUX32;
    }

  /* Always set the personallity, and clear all weird flags */
  personality (pers);

#ifdef ENABLE_SECCOMP
  if (!setup_seccomp (bwrap, arch, pers, flags, error))
    return FALSE;
#endif

  if ((flags & FLATPAK_RUN_FLAG_WRITABLE_ETC) == 0)
    add_monitor_path_args ((flags & FLATPAK_RUN_FLAG_NO_SESSION_HELPER) == 0, bwrap);

  return TRUE;
}

static gboolean
forward_file (XdpDbusDocuments *documents,
              const char       *app_id,
              const char       *file,
              char            **out_doc_id,
              GError          **error)
{
  int fd, fd_id;
  struct stat stbuf;
  guint portal_version;
  gboolean is_dir = FALSE;
  g_autofree char *doc_id = NULL;
  g_autoptr(GUnixFDList) fd_list = NULL;
  const char *perms[] = { "read", "write", NULL };

  fd = open (file, O_PATH | O_CLOEXEC);
  if (fd == -1)
    return flatpak_fail (error, _("Failed to open ‘%s’"), file);

  fd_list = g_unix_fd_list_new ();
  fd_id = g_unix_fd_list_append (fd_list, fd, error);
  if (fstat (fd, &stbuf) == 0 && S_ISDIR (stbuf.st_mode))
    is_dir = TRUE;
  close (fd);

  portal_version = xdp_dbus_documents_get_version (documents);
  if (portal_version < 4 && is_dir)
      return flatpak_fail (error, _("Directory forwarding needs version 4 of the document portal (have version %d)"), portal_version);

  if (portal_version >= 2)
    {
      guint flags = DOCUMENT_ADD_FLAGS_REUSE_EXISTING;
      g_auto(GStrv) doc_ids = NULL;

      if (is_dir)
        flags |= DOCUMENT_ADD_FLAGS_DIRECTORY;

      if (!xdp_dbus_documents_call_add_full_sync (documents,
                                                  g_variant_new_fixed_array (G_VARIANT_TYPE_HANDLE, &fd_id, 1, sizeof (gint32)),
                                                  flags,
                                                  app_id,
                                                  perms,
                                                  fd_list,
                                                  &doc_ids,
                                                  NULL,
                                                  NULL,
                                                  NULL,
                                                  error))
        {
          if (error)
            g_dbus_error_strip_remote_error (*error);
          return FALSE;
        }

      /* doc_ids should have value when xdp_dbus_documents_call_add_full_sync succeeds. */
      g_assert (doc_ids && doc_ids[0]);
      doc_id = g_strdup (doc_ids[0]);
    }
  else
    {
      /* Fallback to plain org.freedesktop.portal.Documents.Add and
         org.freedesktop.portal.Documents.GrantPermissions if interface version is older.
         This does not support directory export. */
      if (!xdp_dbus_documents_call_add_sync (documents,
                                             g_variant_new ("h", fd_id),
                                             TRUE, /* reuse */
                                             FALSE, /* not persistent */
                                             fd_list,
                                             &doc_id,
                                             NULL,
                                             NULL,
                                             error))
        {
          if (error)
            g_dbus_error_strip_remote_error (*error);
          return FALSE;
        }

      if (!xdp_dbus_documents_call_grant_permissions_sync (documents,
                                                           doc_id,
                                                           app_id,
                                                           perms,
                                                           NULL,
                                                           error))
        {
          if (error)
            g_dbus_error_strip_remote_error (*error);
          return FALSE;
        }
    }

  *out_doc_id = g_steal_pointer (&doc_id);

  return TRUE;
}

static gboolean
add_rest_args (FlatpakBwrap   *bwrap,
               const char     *app_id,
               FlatpakExports *exports,
               gboolean        file_forwarding,
               const char     *doc_mount_path,
               char           *args[],
               int             n_args,
               GError        **error)
{
  g_autoptr(AutoXdpDbusDocuments) documents = NULL;
  gboolean forwarding = FALSE;
  gboolean forwarding_uri = FALSE;
  gboolean can_forward = TRUE;
  int i;

  if (file_forwarding && doc_mount_path == NULL)
    {
      g_message ("Can't get document portal mount path");
      can_forward = FALSE;
    }
  else if (file_forwarding)
    {
      g_autoptr(GError) local_error = NULL;

      documents = xdp_dbus_documents_proxy_new_for_bus_sync (G_BUS_TYPE_SESSION, 0,
                                                             "org.freedesktop.portal.Documents",
                                                             "/org/freedesktop/portal/documents",
                                                             NULL,
                                                             &local_error);
      if (documents == NULL)
        {
          g_message ("Can't get document portal: %s", local_error->message);
          can_forward = FALSE;
        }
    }

  for (i = 0; i < n_args; i++)
    {
      g_autoptr(GFile) file = NULL;

      if (file_forwarding &&
          (strcmp (args[i], "@@") == 0 ||
           strcmp (args[i], "@@u") == 0))
        {
          forwarding_uri = strcmp (args[i], "@@u") == 0;
          forwarding = !forwarding;
          continue;
        }

      if (can_forward && forwarding)
        {
          if (forwarding_uri)
            {
              if (g_str_has_prefix (args[i], "file:"))
                file = g_file_new_for_uri (args[i]);
              else if (G_IS_DIR_SEPARATOR (args[i][0]))
                file = g_file_new_for_path (args[i]);
            }
          else
            file = g_file_new_for_path (args[i]);
        }

      if (file && !flatpak_exports_path_is_visible (exports,
                                                    flatpak_file_get_path_cached (file)))
        {
          g_autofree char *doc_id = NULL;
          g_autofree char *basename = NULL;
          g_autofree char *doc_path = NULL;
          if (!forward_file (documents, app_id, flatpak_file_get_path_cached (file),
                             &doc_id, error))
            return FALSE;

          basename = g_file_get_basename (file);
          doc_path = g_build_filename (doc_mount_path, doc_id, basename, NULL);

          if (forwarding_uri)
            {
              g_autofree char *path = doc_path;
              doc_path = g_filename_to_uri (path, NULL, NULL);
              /* This should never fail */
              g_assert (doc_path != NULL);
            }

          g_info ("Forwarding file '%s' as '%s' to %s", args[i], doc_path, app_id);
          flatpak_bwrap_add_arg (bwrap, doc_path);
        }
      else
        flatpak_bwrap_add_arg (bwrap, args[i]);
    }

  return TRUE;
}

FlatpakContext *
flatpak_context_load_for_deploy (FlatpakDeploy *deploy,
                                 GError       **error)
{
  g_autoptr(FlatpakContext) context = NULL;
  g_autoptr(FlatpakContext) overrides = NULL;
  g_autoptr(GKeyFile) metakey = NULL;

  metakey = flatpak_deploy_get_metadata (deploy);
  context = flatpak_app_compute_permissions (metakey, NULL, error);
  if (context == NULL)
    return NULL;

  overrides = flatpak_deploy_get_overrides (deploy);
  flatpak_context_merge (context, overrides);

  return g_steal_pointer (&context);
}

static char *
calculate_ld_cache_checksum (GBytes   *app_deploy_data,
                             GBytes   *runtime_deploy_data,
                             const char *app_extensions,
                             const char *runtime_extensions)
{
  g_autoptr(GChecksum) ld_so_checksum = g_checksum_new (G_CHECKSUM_SHA256);
  if (app_deploy_data)
    g_checksum_update (ld_so_checksum, (guchar *) flatpak_deploy_data_get_commit (app_deploy_data), -1);
  g_checksum_update (ld_so_checksum, (guchar *) flatpak_deploy_data_get_commit (runtime_deploy_data), -1);
  if (app_extensions)
    g_checksum_update (ld_so_checksum, (guchar *) app_extensions, -1);
  if (runtime_extensions)
    g_checksum_update (ld_so_checksum, (guchar *) runtime_extensions, -1);

  return g_strdup (g_checksum_get_string (ld_so_checksum));
}

static gboolean
add_ld_so_conf (FlatpakBwrap *bwrap,
                GError      **error)
{
  const char *contents =
    "include /run/flatpak/ld.so.conf.d/app-*.conf\n"
    "include /app/etc/ld.so.conf\n"
    "/app/lib\n"
    "include /run/flatpak/ld.so.conf.d/runtime-*.conf\n";

  return flatpak_bwrap_add_args_data (bwrap, "ld-so-conf",
                                      contents, -1, "/etc/ld.so.conf", error);
}

static int
regenerate_ld_cache (GPtrArray    *base_argv_array,
                     GArray       *base_fd_array,
                     GFile        *app_id_dir,
                     const char   *checksum,
                     int           runtime_fd,
                     gboolean      generate_ld_so_conf,
                     GCancellable *cancellable,
                     GError      **error)
{
  g_autoptr(FlatpakBwrap) bwrap = NULL;
  g_autoptr(GArray) combined_fd_array = NULL;
  g_autoptr(GFile) ld_so_cache = NULL;
  g_autoptr(GFile) ld_so_cache_tmp = NULL;
  g_autofree char *sandbox_cache_path = NULL;
  g_autofree char *tmp_basename = NULL;
  g_auto(GStrv) minimal_envp = NULL;
  g_autofree char *commandline = NULL;
  int exit_status;
  glnx_autofd int ld_so_fd = -1;
  g_autoptr(GFile) ld_so_dir = NULL;

  if (app_id_dir)
    ld_so_dir = g_file_get_child (app_id_dir, ".ld.so");
  else
    {
      g_autoptr(GFile) base_dir = g_file_new_for_path (g_get_user_cache_dir ());
      ld_so_dir = g_file_resolve_relative_path (base_dir, "flatpak/ld.so");
    }

  ld_so_cache = g_file_get_child (ld_so_dir, checksum);
  ld_so_fd = open (flatpak_file_get_path_cached (ld_so_cache), O_RDONLY);
  if (ld_so_fd >= 0)
    return g_steal_fd (&ld_so_fd);

  g_info ("Regenerating ld.so.cache %s", flatpak_file_get_path_cached (ld_so_cache));

  if (!flatpak_mkdir_p (ld_so_dir, cancellable, error))
    return FALSE;

  minimal_envp = flatpak_run_get_minimal_env (FALSE, FALSE);
  bwrap = flatpak_bwrap_new (minimal_envp);

  flatpak_bwrap_append_args (bwrap, base_argv_array);

  flatpak_run_setup_usr_links (bwrap, runtime_fd, NULL);

  if (generate_ld_so_conf)
    {
      if (!add_ld_so_conf (bwrap, error))
        return -1;
    }
  else
    flatpak_bwrap_add_args (bwrap,
                            "--symlink", "../usr/etc/ld.so.conf", "/etc/ld.so.conf",
                            NULL);

  tmp_basename = g_strconcat (checksum, ".XXXXXX", NULL);
  glnx_gen_temp_name (tmp_basename);

  sandbox_cache_path = g_build_filename ("/run/ld-so-cache-dir", tmp_basename, NULL);
  ld_so_cache_tmp = g_file_get_child (ld_so_dir, tmp_basename);

  flatpak_bwrap_add_args (bwrap,
                          "--unshare-pid",
                          "--unshare-ipc",
                          "--unshare-net",
                          "--proc", "/proc",
                          "--dev", "/dev",
                          "--bind", flatpak_file_get_path_cached (ld_so_dir), "/run/ld-so-cache-dir",
                          NULL);
  flatpak_bwrap_sort_envp (bwrap);
  flatpak_bwrap_envp_to_args (bwrap);

  if (!flatpak_bwrap_bundle_args (bwrap, 1, -1, FALSE, error))
    return -1;

  flatpak_bwrap_add_args (bwrap,
                          "ldconfig", "-X", "-C", sandbox_cache_path, NULL);

  flatpak_bwrap_finish (bwrap);

  commandline = flatpak_quote_argv ((const char **) bwrap->argv->pdata, -1);
  g_info ("Running: '%s'", commandline);

  combined_fd_array = g_array_new (FALSE, TRUE, sizeof (int));
  g_array_append_vals (combined_fd_array, base_fd_array->data, base_fd_array->len);
  g_array_append_vals (combined_fd_array, bwrap->fds->data, bwrap->fds->len);

  /* We use LEAVE_DESCRIPTORS_OPEN and close them in the child_setup
   * to work around a deadlock in GLib < 2.60 */
  if (!g_spawn_sync (NULL,
                     (char **) bwrap->argv->pdata,
                     bwrap->envp,
                     G_SPAWN_SEARCH_PATH | G_SPAWN_LEAVE_DESCRIPTORS_OPEN,
                     flatpak_bwrap_child_setup_cb, combined_fd_array,
                     NULL, NULL,
                     &exit_status,
                     error))
    return -1;

  if (!WIFEXITED (exit_status) || WEXITSTATUS (exit_status) != 0)
    {
      flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED,
                          _("ldconfig failed, exit status %d"), exit_status);
      return -1;
    }

  ld_so_fd = open (flatpak_file_get_path_cached (ld_so_cache_tmp), O_RDONLY);
  if (ld_so_fd < 0)
    {
      flatpak_fail_error (error, FLATPAK_ERROR_SETUP_FAILED, _("Can't open generated ld.so.cache"));
      return -1;
    }

  if (app_id_dir == NULL)
    {
      /* For runs without an app id dir we always regenerate the ld.so.cache */
      unlink (flatpak_file_get_path_cached (ld_so_cache_tmp));
    }
  else
    {
      g_autoptr(GFile) active = g_file_get_child (ld_so_dir, "active");

      /* For app-dirs we keep one checksum alive, by pointing the active symlink to it */

      /* Rename to known name, possibly overwriting existing ref if race */
      if (rename (flatpak_file_get_path_cached (ld_so_cache_tmp), flatpak_file_get_path_cached (ld_so_cache)) == -1)
        {
          glnx_set_error_from_errno (error);
          return -1;
        }

      if (!flatpak_switch_symlink_and_remove (flatpak_file_get_path_cached (active),
                                              checksum, error))
        return -1;
    }

  return g_steal_fd (&ld_so_fd);
}

/* Check that this user is actually allowed to run this app. When running
 * from the gnome-initial-setup session, an app filter might not be available. */
static gboolean
check_parental_controls (FlatpakDecomposed *app_ref,
                         FlatpakDeploy     *deploy,
                         GCancellable      *cancellable,
                         GError           **error)
{
#ifdef HAVE_LIBMALCONTENT
  g_autoptr(MctManager) manager = NULL;
  g_autoptr(MctAppFilter) app_filter = NULL;
  g_autoptr(GDBusConnection) system_bus = NULL;
  g_autoptr(GError) local_error = NULL;
  g_autoptr(GDesktopAppInfo) app_info = NULL;
  gboolean allowed = FALSE;

  system_bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &local_error);
  if (system_bus == NULL)
    {
      /* Since the checks below allow access when malcontent or
       * accounts-service aren't available on the bus, this whole routine can
       * be trivially bypassed by setting DBUS_SYSTEM_BUS_ADDRESS to a
       * temporary dbus-daemon. Not being able to connect to the system bus is
       * basically equivalent.
       */
      g_debug ("Skipping parental controls check for %s since D-Bus system "
               "bus connection failed: %s",
               flatpak_decomposed_get_ref (app_ref),
               local_error ? local_error->message : "unknown reason");
      return TRUE;
    }

  manager = mct_manager_new (system_bus);
  app_filter = mct_manager_get_app_filter (manager, getuid (),
                                           MCT_MANAGER_GET_VALUE_FLAGS_INTERACTIVE,
                                           cancellable, &local_error);
  if (g_error_matches (local_error, MCT_MANAGER_ERROR, MCT_MANAGER_ERROR_DISABLED))
    {
      g_info ("Skipping parental controls check for %s since parental "
              "controls are disabled globally", flatpak_decomposed_get_ref (app_ref));
      return TRUE;
    }
  else if (g_error_matches (local_error, G_DBUS_ERROR, G_DBUS_ERROR_SERVICE_UNKNOWN) ||
           g_error_matches (local_error, G_DBUS_ERROR, G_DBUS_ERROR_NAME_HAS_NO_OWNER))
    {
      g_info ("Skipping parental controls check for %s since a required "
              "service was not found", flatpak_decomposed_get_ref (app_ref));
      return TRUE;
    }
  else if (local_error != NULL)
    {
      g_propagate_error (error, g_steal_pointer (&local_error));
      return FALSE;
    }

  /* Always filter by app ID. Additionally, filter by app info (which runs
   * multiple checks, including whether the app ID, executable path and
   * content types are allowed) if available. If the flatpak contains
   * multiple .desktop files, we use the main one. The app ID check is
   * always done, as the binary executed by `flatpak run` isn’t necessarily
   * extracted from a .desktop file. */
  allowed = mct_app_filter_is_flatpak_ref_allowed (app_filter, flatpak_decomposed_get_ref (app_ref));

  /* Look up the app’s main .desktop file. */
  if (deploy != NULL && allowed)
    {
      g_autoptr(GFile) deploy_dir = NULL;
      const char *deploy_path;
      g_autofree char *desktop_file_name = NULL;
      g_autofree char *desktop_file_path = NULL;
      g_autofree char *app_id = flatpak_decomposed_dup_id (app_ref);

      deploy_dir = flatpak_deploy_get_dir (deploy);
      deploy_path = flatpak_file_get_path_cached (deploy_dir);

      desktop_file_name = g_strconcat (app_id, ".desktop", NULL);
      desktop_file_path = g_build_path (G_DIR_SEPARATOR_S,
                                        deploy_path,
                                        "export",
                                        "share",
                                        "applications",
                                        desktop_file_name,
                                        NULL);
      app_info = g_desktop_app_info_new_from_filename (desktop_file_path);
    }

  if (app_info != NULL)
    allowed = allowed && mct_app_filter_is_appinfo_allowed (app_filter,
                                                            G_APP_INFO (app_info));

  if (!allowed)
    return flatpak_fail_error (error, FLATPAK_ERROR_PERMISSION_DENIED,
                               /* Translators: The placeholder is for an app ref. */
                               _("Running %s is not allowed by the policy set by your administrator"),
                               flatpak_decomposed_get_ref (app_ref));
#endif  /* HAVE_LIBMALCONTENT */

  return TRUE;
}

static int
open_namespace_fd_if_needed (const char *path,
                             const char *other_path) {
  struct stat s, other_s;

  if (stat (path, &s) != 0)
    return -1; /* No such namespace, ignore */

  if (stat (other_path, &other_s) != 0)
    return -1; /* No such namespace, ignore */

  /* setns calls fail if the process is already in the desired namespace, hence the
     check here to ensure the namespaces are different. */
  if (s.st_ino != other_s.st_ino)
    return open (path, O_RDONLY|O_CLOEXEC);

  return -1;
}

FlatpakContextShares
flatpak_run_compute_allowed_shares (FlatpakContext *context)
{
  return flatpak_context_compute_allowed_shares (context,
                                                 flatpak_run_evaluate_conditions);
}

FlatpakContextDevices
flatpak_run_compute_allowed_devices (FlatpakContext *context)
{
  return flatpak_context_compute_allowed_devices (context,
                                                  flatpak_run_evaluate_conditions);
}

FlatpakContextSockets
flatpak_run_compute_allowed_sockets (FlatpakContext *context)
{
  return flatpak_context_compute_allowed_sockets (context,
                                                  flatpak_run_evaluate_conditions);
}

FlatpakContextFeatures
flatpak_run_compute_allowed_features (FlatpakContext *context)
{
  return flatpak_context_compute_allowed_features (context,
                                                   flatpak_run_evaluate_conditions);
}

gboolean
flatpak_run_app (FlatpakDecomposed   *app_ref,
                 FlatpakDeploy       *app_deploy,
                 int                  custom_app_fd,
                 FlatpakContext      *extra_context,
                 const char          *custom_runtime,
                 const char          *custom_runtime_version,
                 const char          *custom_runtime_commit,
                 int                  custom_runtime_fd,
                 int                  parent_pid,
                 FlatpakRunFlags      flags,
                 const char          *cwd,
                 const char          *custom_command,
                 char                *args[],
                 int                  n_args,
                 int                  instance_id_fd,
                 const char * const  *run_environ,
                 char               **instance_dir_out,
                 GArray              *bind_fds,
                 GArray              *ro_bind_fds,
                 GCancellable        *cancellable,
                 GError             **error)
{
  g_autoptr(FlatpakDeploy) runtime_deploy = NULL;
  g_autoptr(GBytes) runtime_deploy_data = NULL;
  g_autoptr(GBytes) app_deploy_data = NULL;
  g_autoptr(GFile) app_id_dir = NULL;
  g_autoptr(GFile) real_app_id_dir = NULL;
  g_autofree char *default_runtime_pref = NULL;
  g_autoptr(FlatpakDecomposed) default_runtime = NULL;
  g_autofree char *default_command = NULL;
  g_autoptr(GKeyFile) metakey = NULL;
  g_autoptr(GKeyFile) runtime_metakey = NULL;
  g_autoptr(FlatpakBwrap) bwrap = NULL;
  const char *command = "/bin/sh";
  g_autoptr(GError) my_error = NULL;
  g_autoptr(FlatpakDecomposed) runtime_ref = NULL;
  int i;
  g_autoptr(GPtrArray) previous_app_id_dirs = NULL;
  g_autofree char *app_id = NULL;
  g_autofree char *app_arch = NULL;
  g_autofree char *app_info_path = NULL;
  g_autofree char *app_ld_path = NULL;
  g_autofree char *instance_id_host_dir = NULL;
  g_autofree char *instance_id_host_private_dir = NULL;
  g_autofree char *instance_id = NULL;
  g_autoptr(FlatpakContext) app_context = NULL;
  g_autoptr(FlatpakContext) overrides = NULL;
  g_autoptr(FlatpakExports) exports = NULL;
  g_autofree char *commandline = NULL;
  g_autofree char *doc_mount_path = NULL;
  g_autofree char *app_extensions = NULL;
  g_autofree char *runtime_extensions = NULL;
  g_autofree char *runtime_ld_path = NULL;
  g_autofree char *checksum = NULL;
  glnx_autofd int per_app_dir_lock_fd = -1;
  g_autofree char *per_app_dir_lock_path = NULL;
  g_autofree char *shared_xdg_runtime_dir = NULL;
  int ld_so_fd = -1;
  gboolean generate_ld_so_conf = TRUE;
  gboolean use_ld_so_cache = TRUE;
  gboolean sandboxed = (flags & FLATPAK_RUN_FLAG_SANDBOX) != 0;
  gboolean parent_expose_pids = (flags & FLATPAK_RUN_FLAG_PARENT_EXPOSE_PIDS) != 0;
  gboolean parent_share_pids = (flags & FLATPAK_RUN_FLAG_PARENT_SHARE_PIDS) != 0;
  FlatpakContextShares shares;
  FlatpakContextDevices devices;
  FlatpakContextSockets sockets;
  FlatpakContextFeatures features;
  glnx_autofd int original_runtime_fd = -1;
  g_autoptr(GFile) original_runtime_files = NULL;
  g_autoptr(GFile) custom_runtime_files = NULL;
  /* borrows from either original_runtime_fd or custom_runtime_fd */
  int runtime_fd = -1;
  /* borrows from either original_runtime_files or custom_runtime_files */
  GFile *runtime_files = NULL;
  const char *original_runtime_target_path = NULL;
  glnx_autofd int original_app_fd = -1;
  g_autoptr(GFile) original_app_files = NULL;
  g_autoptr(GFile) custom_app_files = NULL;
  /* borrows from either original_app_fd or custom_app_fd */
  int app_fd = -1;
  /* borrows from either original_app_files or custom_app_files */
  GFile *app_files = NULL;
  const char *original_app_target_path = NULL;

  g_assert (run_environ != NULL);

  g_return_val_if_fail (app_ref != NULL, FALSE);

  g_return_val_if_fail (custom_app_fd == FLATPAK_RUN_APP_DEPLOY_APP_ORIGINAL ||
                        custom_app_fd == FLATPAK_RUN_APP_DEPLOY_APP_EMPTY ||
                        custom_app_fd >= 0,
                        FALSE);

  g_return_val_if_fail (custom_runtime_fd == FLATPAK_RUN_APP_DEPLOY_USR_ORIGINAL ||
                        custom_runtime_fd >= 0,
                        FALSE);

  /* This check exists to stop accidental usage of `sudo flatpak run`
     and is not to prevent running as root.
   */
  if (running_under_sudo_root ())
    return flatpak_fail_error (error, FLATPAK_ERROR,
                               _("\"flatpak run\" is not intended to be run as `sudo flatpak run`. "
                                 "Use `sudo -i` or `su -l` instead and invoke \"flatpak run\" from "
                                 "inside the new shell."));

  app_id = flatpak_decomposed_dup_id (app_ref);
  g_return_val_if_fail (app_id != NULL, FALSE);
  app_arch = flatpak_decomposed_dup_arch (app_ref);
  g_return_val_if_fail (app_arch != NULL, FALSE);

  /* Check the user is allowed to run this flatpak. */
  if (!check_parental_controls (app_ref, app_deploy, cancellable, error))
    return FALSE;

  /* Construct the bwrap context. */
  bwrap = flatpak_bwrap_new (NULL);
  flatpak_bwrap_add_arg (bwrap, flatpak_get_bwrap ());

  if (app_deploy == NULL)
    {
      g_assert (flatpak_decomposed_is_runtime (app_ref));
      default_runtime_pref = flatpak_decomposed_dup_pref (app_ref);
    }
  else
    {
      const gchar *key;

      app_deploy_data = flatpak_deploy_get_deploy_data (app_deploy, FLATPAK_DEPLOY_VERSION_ANY, cancellable, error);
      if (app_deploy_data == NULL)
        return FALSE;

      if ((flags & FLATPAK_RUN_FLAG_DEVEL) != 0)
        key = FLATPAK_METADATA_KEY_SDK;
      else
        key = FLATPAK_METADATA_KEY_RUNTIME;

      metakey = flatpak_deploy_get_metadata (app_deploy);
      default_runtime_pref = g_key_file_get_string (metakey,
                                                    FLATPAK_METADATA_GROUP_APPLICATION,
                                                    key, &my_error);
      if (my_error)
        {
          g_propagate_error (error, g_steal_pointer (&my_error));
          return FALSE;
        }
    }

  default_runtime = flatpak_decomposed_new_from_pref (FLATPAK_KINDS_RUNTIME, default_runtime_pref, error);
  if (default_runtime == NULL)
    return FALSE;

  if (custom_runtime != NULL || custom_runtime_version != NULL)
    {
      g_auto(GStrv) custom_runtime_parts = NULL;
      const char *custom_runtime_id = NULL;
      const char *custom_runtime_arch = NULL;

      if (custom_runtime)
        {
          custom_runtime_parts = g_strsplit (custom_runtime, "/", 0);
          for (i = 0; i < 3 && custom_runtime_parts[i] != NULL; i++)
            {
              if (strlen (custom_runtime_parts[i]) > 0)
                {
                  if (i == 0)
                    custom_runtime_id = custom_runtime_parts[i];
                  if (i == 1)
                    custom_runtime_arch = custom_runtime_parts[i];

                  if (i == 2 && custom_runtime_version == NULL)
                    custom_runtime_version = custom_runtime_parts[i];
                }
            }
        }

      runtime_ref = flatpak_decomposed_new_from_decomposed (default_runtime,
                                                            FLATPAK_KINDS_RUNTIME,
                                                            custom_runtime_id,
                                                            custom_runtime_arch,
                                                            custom_runtime_version,
                                                            error);
      if (runtime_ref == NULL)
        return FALSE;
    }
  else
    runtime_ref = flatpak_decomposed_ref (default_runtime);

  runtime_deploy = flatpak_find_deploy_for_ref (flatpak_decomposed_get_ref (runtime_ref), custom_runtime_commit, NULL, cancellable, error);
  if (runtime_deploy == NULL)
    return FALSE;

  runtime_deploy_data = flatpak_deploy_get_deploy_data (runtime_deploy, FLATPAK_DEPLOY_VERSION_ANY, cancellable, error);
  if (runtime_deploy_data == NULL)
    return FALSE;

  runtime_metakey = flatpak_deploy_get_metadata (runtime_deploy);

  app_context = flatpak_app_compute_permissions (metakey, runtime_metakey, error);
  if (app_context == NULL)
    return FALSE;

  if (app_deploy != NULL)
    {
      overrides = flatpak_deploy_get_overrides (app_deploy);
      flatpak_context_merge (app_context, overrides);
    }

  if (sandboxed)
    {
      flatpak_context_make_sandboxed (app_context);
      flatpak_context_dump (app_context, "After making sandboxed");
    }

  if (extra_context)
    {
      flatpak_context_dump (extra_context, "Command-line overrides");
      flatpak_context_merge (app_context, extra_context);
    }

  flatpak_context_dump (app_context, "Final context");

  shares = flatpak_run_compute_allowed_shares (app_context);
  devices = flatpak_run_compute_allowed_devices (app_context);
  sockets = flatpak_run_compute_allowed_sockets (app_context);
  features = flatpak_run_compute_allowed_features (app_context);

  original_runtime_files = flatpak_deploy_get_files (runtime_deploy);
  original_runtime_fd = open (flatpak_file_get_path_cached (original_runtime_files),
                              O_PATH | O_CLOEXEC);
  if (original_runtime_fd < 0)
    return glnx_throw_errno_prefix (error, "Failed to open original runtime");

  if (custom_runtime_fd >= 0)
    {
      g_autofree char *path = NULL;

      path = flatpak_get_path_for_fd (custom_runtime_fd, &my_error);
      if (path == NULL)
        {
          return flatpak_fail_error (error, FLATPAK_ERROR,
                                     "Cannot convert custom usr fd to path: %s",
                                     my_error->message);
        }

      custom_runtime_files = g_file_new_for_path (path);

      original_runtime_target_path = "/run/parent/usr";
      runtime_fd = custom_runtime_fd;
      runtime_files = custom_runtime_files;
    }
  else if (custom_runtime_fd == FLATPAK_RUN_APP_DEPLOY_USR_ORIGINAL)
    {
      original_runtime_target_path = "/usr";
      runtime_fd = original_runtime_fd;
      runtime_files = original_runtime_files;
    }
  else
    {
      g_assert_not_reached ();
    }

  if (app_deploy != NULL)
    {
      g_autofree const char **previous_ids = NULL;
      gsize len = 0;
      gboolean do_migrate;

      original_app_files = flatpak_deploy_get_files (app_deploy);
      original_app_fd = open (flatpak_file_get_path_cached (original_app_files),
                              O_PATH | O_CLOEXEC | O_NOFOLLOW);
      if (original_app_fd < 0)
        return glnx_throw_errno_prefix (error, "Failed to open original runtime");

      real_app_id_dir = flatpak_get_data_dir (app_id);

      previous_app_id_dirs = g_ptr_array_new_with_free_func (g_object_unref);
      previous_ids = flatpak_deploy_data_get_previous_ids (app_deploy_data, &len);

      do_migrate = !g_file_query_exists (real_app_id_dir, cancellable);

      /* When migrating, find most recent old existing source and rename that to
       * the new name.
       *
       * We ignore other names than that. For more recent names that don't exist
       * we never ran them so nothing will even reference them. For older names
       * either they were not used, or they were used but then the more recent
       * name was used and a symlink to it was created.
       *
       * This means we may end up with a chain of symlinks: oldest -> old -> current.
       * This is unfortunate but not really a problem, but for robustness reasons we
       * don't want to mess with user files unnecessary. For example, the app dir could
       * actually be a symlink for other reasons. Imagine for instance that you want to put the
       * steam games somewhere else so you leave the app dir as a symlink to /mnt/steam.
       */
      for (i = len - 1; i >= 0; i--)
        {
          g_autoptr(GFile) previous_app_id_dir = NULL;
          g_autoptr(GFileInfo) previous_app_id_dir_info = NULL;
          g_autoptr(GError) local_error = NULL;

          previous_app_id_dir = flatpak_get_data_dir (previous_ids[i]);
          previous_app_id_dir_info = g_file_query_info (previous_app_id_dir,
                                                        G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK ","
                                                        G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET,
                                                        G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
                                                        cancellable,
                                                        &local_error);
          /* Warn about the migration failures, but don't make them fatal, then you can never run the app */
          if (previous_app_id_dir_info == NULL)
            {
              if  (!g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND) && do_migrate)
                {
                  g_warning (_("Failed to migrate from %s: %s"), flatpak_file_get_path_cached (previous_app_id_dir),
                             local_error->message);
                  do_migrate = FALSE; /* Don't migrate older things, they are likely symlinks to the thing that we failed on */
                }

              g_clear_error (&local_error);
              continue;
            }

          if (do_migrate)
            {
              do_migrate = FALSE; /* Don't migrate older things, they are likely symlinks to this dir */

              /* Don't migrate a symlink pointing to the new data dir. It was likely left over
               * from a previous migration and would end up pointing to itself */
              if (g_file_info_get_is_symlink (previous_app_id_dir_info) &&
                  g_strcmp0 (g_file_info_get_symlink_target (previous_app_id_dir_info), app_id) == 0)
                break;

              if (!flatpak_file_rename (previous_app_id_dir, real_app_id_dir, cancellable, &local_error))
                {
                  g_warning (_("Failed to migrate old app data directory %s to new name %s: %s"),
                             flatpak_file_get_path_cached (previous_app_id_dir), app_id,
                             local_error->message);
                }
              else
                {
                  /* Leave a symlink in place of the old data dir */
                  if (!g_file_make_symbolic_link (previous_app_id_dir, app_id, cancellable, &local_error))
                    {
                      g_warning (_("Failed to create symlink while migrating %s: %s"),
                                 flatpak_file_get_path_cached (previous_app_id_dir),
                                 local_error->message);
                    }
                }
            }

          /* Give app access to this old dir */
          g_ptr_array_add (previous_app_id_dirs, g_steal_pointer (&previous_app_id_dir));
        }

      if (!flatpak_ensure_data_dir (real_app_id_dir, cancellable, error))
        return FALSE;

      if (!sandboxed)
        app_id_dir = g_object_ref (real_app_id_dir);
    }

  if (custom_app_fd >= 0)
    {
      g_autofree char *path = NULL;

      path = flatpak_get_path_for_fd (custom_app_fd, error);
      if (path == NULL)
        return glnx_prefix_error (error, "Cannot convert custom app fd to path");

      custom_app_files = g_file_new_for_path (path);

      original_app_target_path = "/run/parent/app";
      app_fd = custom_app_fd;
      app_files = custom_app_files;
    }
  else if (custom_app_fd == FLATPAK_RUN_APP_DEPLOY_APP_ORIGINAL)
    {
      original_app_target_path = "/app";
      app_fd = original_app_fd;
      app_files = original_app_files;
    }
  else if (custom_app_fd == FLATPAK_RUN_APP_DEPLOY_APP_EMPTY)
    {
      original_app_target_path = "/run/parent/app";
      app_fd = -1;
      app_files = NULL;
    }
  else
    {
      g_assert_not_reached ();
    }

  /* We can't use the ld.so cache if we are using a custom /usr or /app,
   * because we don't have a unique ID for the /usr or /app, so we can't
   * do cache-invalidation correctly. The caller can either build their
   * own ld.so.cache before supplying us with the runtime, or supply
   * their own LD_LIBRARY_PATH. */
  if (runtime_fd == custom_runtime_fd || app_fd == custom_app_fd)
    {
      use_ld_so_cache = FALSE;
    }
  else
    {
      glnx_autofd int ldconfig_fd = -1;

      ldconfig_fd = glnx_chaseat (runtime_fd, "bin/ldconfig",
                                  GLNX_CHASE_RESOLVE_BENEATH |
                                  GLNX_CHASE_MUST_BE_REGULAR,
                                  &my_error);
      if (ldconfig_fd < 0)
        {
          use_ld_so_cache = FALSE;
          g_debug ("bin/ldconfig not found in runtime: %s", my_error->message);
        }

      g_clear_error (&my_error);
    }

  flatpak_run_apply_env_clear (bwrap, !!(flags & FLATPAK_RUN_FLAG_CLEAR_ENV));
  flatpak_run_apply_env_default (bwrap, use_ld_so_cache);
  flatpak_run_apply_env_vars (bwrap, app_context);
  flatpak_run_apply_env_prompt (bwrap, app_id);

  if (real_app_id_dir)
    {
      g_autoptr(GFile) sandbox_dir = g_file_get_child (real_app_id_dir, "sandbox");
      flatpak_bwrap_set_env (bwrap, "FLATPAK_SANDBOX_DIR", flatpak_file_get_path_cached (sandbox_dir), TRUE);
    }

  if (!flatpak_bwrap_add_args_data_fd_dup (bwrap,
                                           "--ro-bind-fd", runtime_fd, "/usr",
                                           error))
    return FALSE;

  {
    glnx_autofd int runtime_ref_fd = -1;

    runtime_ref_fd = glnx_chaseat (runtime_fd, ".ref",
                                   GLNX_CHASE_RESOLVE_BENEATH |
                                   GLNX_CHASE_MUST_BE_REGULAR,
                                   NULL);
    if (runtime_ref_fd >= 0)
      {
        flatpak_bwrap_add_args (bwrap,
                                "--lock-file", "/usr/.ref",
                                NULL);
      }
  }

  if (runtime_fd == custom_runtime_fd)
    {
      glnx_autofd int original_runtime_ref_fd = -1;
      glnx_autofd int original_runtime_etc_fd = -1;

      /* Put the real Flatpak runtime in /run/parent, so that the
       * replacement /usr can have symlinks into /run/parent in order
       * to use the Flatpak runtime's graphics drivers etc. if desired */
      if (!flatpak_bwrap_add_args_data_fd_dup (bwrap,
                                               "--ro-bind-fd",
                                               original_runtime_fd,
                                               "/run/parent/usr",
                                               error))
        return FALSE;

      original_runtime_ref_fd = glnx_chaseat (original_runtime_fd, ".ref",
                                              GLNX_CHASE_RESOLVE_BENEATH |
                                              GLNX_CHASE_MUST_BE_REGULAR,
                                              NULL);
      if (original_runtime_ref_fd >= 0)
        {
          flatpak_bwrap_add_args (bwrap,
                                  "--lock-file", "/run/parent/usr/.ref",
                                  NULL);
        }

      original_runtime_etc_fd = glnx_chaseat (original_runtime_fd, "etc",
                                              GLNX_CHASE_RESOLVE_BENEATH |
                                              GLNX_CHASE_MUST_BE_REGULAR,
                                              NULL);
      if (original_runtime_etc_fd >= 0)
        {
          flatpak_bwrap_add_args (bwrap,
                                  "--symlink", "usr/etc", "/run/parent/etc",
                                  NULL);
        }

      flatpak_run_setup_usr_links (bwrap, original_runtime_fd,
                                   "/run/parent");
    }

  if (app_fd >= 0)
    {
      glnx_autofd int app_ref_fd = -1;

      if (!flatpak_bwrap_add_args_data_fd_dup (bwrap,
                                               "--ro-bind-fd", app_fd, "/app",
                                               error))
        return FALSE;

      app_ref_fd = glnx_chaseat (app_fd, ".ref",
                                 GLNX_CHASE_RESOLVE_BENEATH |
                                 GLNX_CHASE_MUST_BE_REGULAR,
                                 NULL);
      if (app_ref_fd >= 0)
        {
          flatpak_bwrap_add_args (bwrap,
                                  "--lock-file", "/app/.ref",
                                  NULL);
        }
    }
  else
    {
      flatpak_bwrap_add_args (bwrap,
                              "--dir", "/app",
                              NULL);
    }

  if (original_app_fd >= 0 && original_app_fd != app_fd)
    {
      /* Put the real Flatpak app in /run/parent/app */
      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind",
                              flatpak_file_get_path_cached (original_app_files),
                              "/run/parent/app",
                              "--lock-file", "/run/parent/app/.ref",
                              NULL);
    }

  if (metakey != NULL &&
      !flatpak_run_add_extension_args (bwrap, metakey, app_ref,
                                       use_ld_so_cache, original_app_target_path,
                                       &app_extensions, &app_ld_path,
                                       cancellable, error))
    return FALSE;

  if (!flatpak_run_add_extension_args (bwrap, runtime_metakey, runtime_ref,
                                       use_ld_so_cache, original_runtime_target_path,
                                       &runtime_extensions, &runtime_ld_path,
                                       cancellable, error))
    return FALSE;

  if (runtime_fd == original_runtime_fd)
    flatpak_run_extend_ld_path (bwrap, NULL, runtime_ld_path);

  if (app_fd == original_app_fd)
    flatpak_run_extend_ld_path (bwrap, app_ld_path, NULL);

  {
    glnx_autofd int ld_so_conf_fd = -1;
    struct glnx_statx stx;

    ld_so_conf_fd = glnx_chase_and_statxat (runtime_fd, "etc/ld.so.conf",
                                            GLNX_CHASE_RESOLVE_BENEATH |
                                            GLNX_CHASE_MUST_BE_REGULAR,
                                            GLNX_STATX_SIZE,
                                            &stx, NULL);
    if (ld_so_conf_fd < 0 ||
        !(stx.stx_mask & GLNX_STATX_SIZE) ||
        stx.stx_size != 0)
      generate_ld_so_conf = FALSE;
  }

  /* At this point we have the minimal argv set up, with just the app, runtime and extensions.
     We can reuse this to generate the ld.so.cache (if needed) */
  if (use_ld_so_cache)
    {
      checksum = calculate_ld_cache_checksum (app_deploy_data, runtime_deploy_data,
                                              app_extensions, runtime_extensions);
      ld_so_fd = regenerate_ld_cache (bwrap->argv,
                                      bwrap->fds,
                                      app_id_dir,
                                      checksum,
                                      runtime_fd,
                                      generate_ld_so_conf,
                                      cancellable, error);
      if (ld_so_fd == -1)
        return FALSE;
      flatpak_bwrap_add_fd (bwrap, ld_so_fd);
    }

  flags |= flatpak_context_features_to_run_flags (features);

  if (!flatpak_run_setup_base_argv (bwrap, runtime_fd, app_id_dir, app_arch, flags, error))
    return FALSE;

  if (generate_ld_so_conf)
    {
      if (!add_ld_so_conf (bwrap, error))
        return FALSE;
    }

  if (ld_so_fd != -1)
    {
      /* Don't add to fd_array, its already there */
      flatpak_bwrap_add_arg (bwrap, "--ro-bind-data");
      flatpak_bwrap_add_arg_printf (bwrap, "%d", ld_so_fd);
      flatpak_bwrap_add_arg (bwrap, "/etc/ld.so.cache");
    }

  if (!flatpak_run_add_app_info_args (bwrap,
                                      app_files, original_app_files, app_deploy_data, app_extensions,
                                      runtime_files, original_runtime_files, runtime_deploy_data, runtime_extensions,
                                      app_id, flatpak_decomposed_get_branch (app_ref),
                                      runtime_ref, app_id_dir,
                                      app_context, extra_context, sockets,
                                      sandboxed, FALSE, flags & FLATPAK_RUN_FLAG_DEVEL,
                                      &app_info_path,
                                      g_steal_fd (&instance_id_fd),
                                      &instance_id_host_dir, &instance_id_host_private_dir,
                                      &instance_id, error))
    return FALSE;

  if (!flatpak_run_save_environ (run_environ,
                                 instance_id_host_private_dir,
                                 cancellable,
                                 error))
    return FALSE;

  if (!sandboxed)
    {
      if (!flatpak_instance_ensure_per_app_dir (app_id,
                                                &per_app_dir_lock_fd,
                                                &per_app_dir_lock_path,
                                                error))
        return FALSE;

      if (!flatpak_instance_ensure_per_app_xdg_runtime_dir (app_id,
                                                            per_app_dir_lock_fd,
                                                            &shared_xdg_runtime_dir,
                                                            error))
        return FALSE;

      flatpak_bwrap_add_arg (bwrap, "--bind");
      flatpak_bwrap_add_arg (bwrap, shared_xdg_runtime_dir);
      flatpak_bwrap_add_arg_printf (bwrap, "/run/user/%d", getuid ());
    }

  if (!flatpak_run_add_dconf_args (bwrap, app_id, metakey, error))
    return FALSE;

  if (!sandboxed && !(flags & FLATPAK_RUN_FLAG_NO_DOCUMENTS_PORTAL))
    add_document_portal_args (bwrap, app_id, &doc_mount_path);

  if (!flatpak_run_add_environment_args (bwrap, app_info_path, flags,
                                         app_id, app_context,
                                         shares, devices, sockets, features,
                                         app_id_dir, previous_app_id_dirs,
                                         per_app_dir_lock_fd, instance_id,
                                         &exports, cancellable, error))
    return FALSE;

  if (per_app_dir_lock_path != NULL)
    {
      static const char lock[] = "/run/flatpak/per-app-dirs-ref";

      flatpak_bwrap_add_args (bwrap,
                              "--ro-bind", per_app_dir_lock_path, lock,
                              "--lock-file", lock,
                              NULL);
    }

  flatpak_run_add_socket_args_late (bwrap, shares);
  add_font_path_args (bwrap);
  add_icon_path_args (bwrap);

  flatpak_bwrap_add_args (bwrap,
                          /* Not in base, because we don't want this for flatpak build */
                          "--symlink", "/app/lib/debug/source", "/run/build",
                          "--symlink", "/usr/lib/debug/source", "/run/build-runtime",
                          NULL);

  for (i = 0; bind_fds && i < bind_fds->len; i++)
    {
      int fd = g_array_index (bind_fds, int, i);
      g_autofree char *path = NULL;

      /* We get the path the fd refers to, to determine to mount point
       * destination inside the sandbox */
      path = flatpak_get_path_for_fd (fd, error);
      if (!path)
        return FALSE;

      if (!flatpak_bwrap_add_args_data_fd_dup (bwrap,
                                               "--bind-fd", fd, path,
                                               error))
        return FALSE;
    }

  for (i = 0; ro_bind_fds && i < ro_bind_fds->len; i++)
    {
      int fd = g_array_index (ro_bind_fds, int, i);
      g_autofree char *path = NULL;

      /* We get the path the fd refers to, to determine to mount point
       * destination inside the sandbox */
      path = flatpak_get_path_for_fd (fd, error);
      if (!path)
        return FALSE;

      if (!flatpak_bwrap_add_args_data_fd_dup (bwrap,
                                               "--ro-bind-fd", fd, path,
                                               error))
        return FALSE;
    }

  if (cwd)
    flatpak_bwrap_add_args (bwrap, "--chdir", cwd, NULL);

  if (parent_expose_pids || parent_share_pids)
    {
      g_autofree char *userns_path = NULL;
      g_autofree char *pidns_path = NULL;
      g_autofree char *userns2_path = NULL;
      int userns_fd, userns2_fd, pidns_fd;

      if (parent_pid == 0)
        return flatpak_fail (error, "No parent pid specified");

      userns_path = g_strdup_printf ("/proc/%d/root/run/.userns", parent_pid);

      userns_fd = open_namespace_fd_if_needed (userns_path, "/proc/self/ns/user");
      if (userns_fd != -1)
        {
          flatpak_bwrap_add_args_data_fd (bwrap, "--userns", userns_fd, NULL);

          userns2_path = g_strdup_printf ("/proc/%d/ns/user", parent_pid);
          userns2_fd = open_namespace_fd_if_needed (userns2_path, userns_path);
          if (userns2_fd != -1)
            flatpak_bwrap_add_args_data_fd (bwrap, "--userns2", userns2_fd, NULL);
        }

      pidns_path = g_strdup_printf ("/proc/%d/ns/pid", parent_pid);
      pidns_fd = open (pidns_path, O_RDONLY|O_CLOEXEC);
      if (pidns_fd != -1)
        flatpak_bwrap_add_args_data_fd (bwrap, "--pidns", pidns_fd, NULL);
    }

  flatpak_bwrap_populate_runtime_dir (bwrap, shared_xdg_runtime_dir);

  if (custom_command)
    {
      command = custom_command;
    }
  else if (metakey)
    {
      default_command = g_key_file_get_string (metakey,
                                               FLATPAK_METADATA_GROUP_APPLICATION,
                                               FLATPAK_METADATA_KEY_COMMAND,
                                               &my_error);
      if (my_error)
        {
          g_propagate_error (error, g_steal_pointer (&my_error));
          return FALSE;
        }
      command = default_command;
    }

  flatpak_bwrap_sort_envp (bwrap);
  flatpak_bwrap_envp_to_args (bwrap);

  if (!flatpak_bwrap_bundle_args (bwrap, 1, -1, FALSE, error))
    return FALSE;

  flatpak_bwrap_add_args (bwrap, "--", command, NULL);

  if (!add_rest_args (bwrap, app_id,
                      exports, (flags & FLATPAK_RUN_FLAG_FILE_FORWARDING) != 0,
                      doc_mount_path,
                      args, n_args, error))
    return FALSE;

  /* Hold onto the lock until we execute bwrap */
  flatpak_bwrap_add_noinherit_fd (bwrap, g_steal_fd (&per_app_dir_lock_fd));

  flatpak_bwrap_finish (bwrap);

  commandline = flatpak_quote_argv ((const char **) bwrap->argv->pdata, -1);
  g_info ("Running '%s'", commandline);

  if ((flags & (FLATPAK_RUN_FLAG_BACKGROUND)) != 0 ||
      g_getenv ("FLATPAK_TEST_COVERAGE") != NULL)
    {
      GPid child_pid;
      char pid_str[64];
      g_autofree char *pid_path = NULL;
      GSpawnFlags spawn_flags;
      GSpawnChildSetupFunc child_setup;

      spawn_flags = G_SPAWN_SEARCH_PATH;
      if (flags & FLATPAK_RUN_FLAG_DO_NOT_REAP ||
          (flags & FLATPAK_RUN_FLAG_BACKGROUND) == 0)
        spawn_flags |= G_SPAWN_DO_NOT_REAP_CHILD;

      if (flags & FLATPAK_RUN_FLAG_BACKGROUND)
        child_setup = flatpak_bwrap_child_setup_cb;
      else
        child_setup = flatpak_bwrap_child_setup_inherit_fds_cb;

      /* Even in the case where we want them closed, we use
       * LEAVE_DESCRIPTORS_OPEN and close them in the child_setup
       * to work around a deadlock in GLib < 2.60 */
      spawn_flags |= G_SPAWN_LEAVE_DESCRIPTORS_OPEN;

      /* flatpak_bwrap_envp_to_args() moved the environment variables to
       * be set into --setenv instructions in argv, so the environment
       * in which the bwrap command runs must be empty. */
      g_assert (bwrap->envp != NULL);
      g_assert (bwrap->envp[0] == NULL);

      if (!g_spawn_async (NULL,
                          (char **) bwrap->argv->pdata,
                          bwrap->envp,
                          spawn_flags,
                          child_setup, bwrap->fds,
                          &child_pid,
                          error))
        return FALSE;

      g_snprintf (pid_str, sizeof (pid_str), "%d", child_pid);
      pid_path = g_build_filename (instance_id_host_dir, "pid", NULL);
      g_file_set_contents (pid_path, pid_str, -1, NULL);

      if ((flags & (FLATPAK_RUN_FLAG_BACKGROUND)) == 0)
        {
          int wait_status;

          if (waitpid (child_pid, &wait_status, 0) != child_pid)
            return glnx_throw_errno_prefix (error, "Failed to wait for child process");

          if (WIFEXITED (wait_status))
            exit (WEXITSTATUS (wait_status));

          if (WIFSIGNALED (wait_status))
            exit (128 + WTERMSIG (wait_status));

          return glnx_throw (error, "Unknown wait status from waitpid(): %d", wait_status);
        }
    }
  else
    {
      char pid_str[64];
      g_autofree char *pid_path = NULL;

      g_snprintf (pid_str, sizeof (pid_str), "%d", getpid ());
      pid_path = g_build_filename (instance_id_host_dir, "pid", NULL);
      g_file_set_contents (pid_path, pid_str, -1, NULL);

      /* Ensure we unset O_CLOEXEC for marked fds and rewind fds as needed.
       * Note that this does not close fds that are not already marked O_CLOEXEC, because
       * we do want to allow inheriting fds into flatpak run. */
      flatpak_bwrap_child_setup (bwrap->fds, FALSE);

      /* flatpak_bwrap_envp_to_args() moved the environment variables to
       * be set into --setenv instructions in argv, so the environment
       * in which the bwrap command runs must be empty. */
      g_assert (bwrap->envp != NULL);
      g_assert (bwrap->envp[0] == NULL);

      if (execvpe (flatpak_get_bwrap (), (char **) bwrap->argv->pdata, bwrap->envp) == -1)
        {
          g_set_error_literal (error, G_IO_ERROR, g_io_error_from_errno (errno),
                               _("Unable to start app"));
          return FALSE;
        }
      /* Not actually reached... */
    }

  if (instance_dir_out)
    *instance_dir_out = g_steal_pointer (&instance_id_host_dir);

  return TRUE;
}
