--- /dev/null
+/*
+ * Copyright © 2023 Collabora Ltd.
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <config.h>
+
+#include <glib.h>
+
+#include <dbus/dbus.h>
+#include "dbus/dbus-sysdeps.h"
+#include "test-utils-glib.h"
+
+#ifdef DBUS_UNIX
+#include <errno.h>
+#include <pwd.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "dbus/dbus-sysdeps-unix.h"
+#include "dbus/dbus-userdb.h"
+#endif
+
+typedef struct
+{
+ int dummy;
+} Fixture;
+
+static void
+setup (Fixture *f G_GNUC_UNUSED,
+ gconstpointer context G_GNUC_UNUSED)
+{
+}
+
+static void
+test_groups_from_uid (Fixture *f,
+ gconstpointer context G_GNUC_UNUSED)
+{
+ DBusError error = DBUS_ERROR_INIT;
+ dbus_gid_t *gids = NULL;
+ int n_gids = -1;
+ dbus_bool_t ret;
+#ifdef DBUS_UNIX
+ int i;
+#endif
+
+ /* We assume that uid 0 (root) is available on all Unix systems,
+ * so this should succeed */
+ ret = _dbus_unix_groups_from_uid (0, &gids, &n_gids, &error);
+
+#ifdef DBUS_UNIX
+ test_assert_no_error (&error);
+ g_assert_true (ret);
+ g_assert_cmpint (n_gids, >=, 0);
+
+ g_test_message ("Groups of uid 0:");
+
+ for (i = 0; i < n_gids; i++)
+ {
+ g_test_message ("[%d]: %ld", i, (long) gids[i]);
+ g_assert_cmpint (gids[i], >=, 0);
+ }
+#else
+ g_assert_cmpstr (error.name, ==, DBUS_ERROR_NOT_SUPPORTED);
+ g_assert_false (ret);
+ g_test_message ("Getting Unix groups on Windows failed as expected: %s: %s",
+ error.name, error.message);
+ g_assert_null (gids);
+ g_assert_cmpint (n_gids, <=, 0);
+#endif
+
+ dbus_free (gids);
+ dbus_error_free (&error);
+
+#ifdef DBUS_UNIX
+ /* Assume that the current uid is something sensible */
+ ret = _dbus_unix_groups_from_uid (geteuid (), &gids, &n_gids, &error);
+ test_assert_no_error (&error);
+ g_assert_true (ret);
+ g_assert_cmpint (n_gids, >=, 0);
+
+ g_test_message ("Groups of uid %ld:", (long) geteuid ());
+
+ for (i = 0; i < n_gids; i++)
+ {
+ g_test_message ("[%d]: %ld", i, (long) gids[i]);
+ g_assert_cmpint (gids[i], >=, 0);
+ }
+
+ g_test_message ("Total: %i groups", n_gids);
+
+ dbus_free (gids);
+ dbus_error_free (&error);
+
+ errno = 0;
+
+ /* arbitrarily chosen, probably isn't a valid uid */
+ if (getpwuid (31337) == NULL)
+ {
+ g_test_message ("uid 31337 doesn't exist: %s",
+ errno == 0 ? "(no errno)" : g_strerror (errno));
+ ret = _dbus_unix_groups_from_uid (31337, &gids, &n_gids, &error);
+ g_assert_nonnull (error.name);
+ g_assert_nonnull (error.message);
+ g_assert_false (ret);
+ g_test_message ("Getting groups from non-uid failed as expected: %s: %s",
+ error.name, error.message);
+ /* The Unix implementation always clears gids/n_gids,
+ * even on failure, and even if they were uninitialized */
+ g_assert_null (gids);
+ g_assert_cmpint (n_gids, ==, 0);
+
+ dbus_free (gids);
+ dbus_error_free (&error);
+ }
+ else
+ {
+ g_test_skip ("against our expectations, uid 31337 exists on this system");
+ }
+#endif
+}
+
+static void
+teardown (Fixture *f G_GNUC_UNUSED,
+ gconstpointer context G_GNUC_UNUSED)
+{
+}
+
+int
+main (int argc,
+ char **argv)
+{
+ int ret;
+
+ test_init (&argc, &argv);
+
+ g_test_add ("/userdb/groups_from_uid",
+ Fixture, NULL, setup, test_groups_from_uid, teardown);
+
+ ret = g_test_run ();
+ dbus_shutdown ();
+ return ret;
+}