wireplumber/modules/module-lua-scripting/config.c

/* WirePlumber
 *
 * Copyright © 2020 Collabora Ltd.
 *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
 *
 * SPDX-License-Identifier: MIT
 */

#include <wp/wp.h>
#include <wplua/wplua.h>
#include <pipewire/pipewire.h>

static gboolean
add_spa_libs (lua_State *L, WpCore * core, GError ** error)
{
  lua_getglobal (L, "SANDBOX_COMMON_ENV");

  switch (lua_getfield (L, -1, "spa_libs")) {
  case LUA_TTABLE:
    break;
  case LUA_TNIL:
    wp_debug ("no spa_libs specified");
    goto done;
  default:
    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
        "Expected 'spa_libs' to be a table");
    return FALSE;
  }

  lua_pushnil (L);
  while (lua_next (L, -2)) {
    if (lua_type (L, -2) != LUA_TSTRING ||
        lua_type (L, -1) != LUA_TSTRING) {
      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
          "'spa_libs' must be a table with string keys and string values");
      return FALSE;
    }

    const gchar *regex = lua_tostring (L, -2);
    const gchar *lib = lua_tostring (L, -1);

    wp_debug ("add spa lib: %s -> %s", regex, lib);

    int ret = pw_context_add_spa_lib (wp_core_get_pw_context (core), regex,
        lib);
    if (ret < 0) {
      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
          "failed to add spa lib ('%s' on '%s'): %s", regex, lib,
          g_strerror (-ret));
      return FALSE;
    }

    lua_pop (L, 1); /* pop the value */
  }

done:
  lua_pop (L, 2); /* pop spa_libs & SANDBOX_COMMON_ENV */
  return TRUE;
}

static GVariant *
lua_to_gvariant (lua_State *L, int index)
{
  GVariantBuilder b;
  g_variant_builder_init (&b, G_VARIANT_TYPE_VARDICT);

  int table = lua_absindex (L, index);

  lua_pushnil (L);
  while (lua_next (L, table)) {
    /* each argument must have a string as key */
    if (lua_type (L, -2) != LUA_TSTRING) {
      wp_warning ("skipping bad component argument key");
      continue; /* skip, it's probably harmless */
    }
    const char *key = lua_tostring (L, -2);

    switch (lua_type (L, -1)) {
    case LUA_TBOOLEAN:
      g_variant_builder_add (&b, "{sv}", key,
          g_variant_new_boolean (lua_toboolean (L, -1)));
      break;

    case LUA_TNUMBER:
      if (lua_isinteger (L, -1)) {
        g_variant_builder_add (&b, "{sv}", key,
            g_variant_new_int64 (lua_tointeger (L, -1)));
      } else {
        g_variant_builder_add (&b, "{sv}", key,
            g_variant_new_double (lua_tonumber (L, -1)));
      }
      break;

    case LUA_TSTRING:
      g_variant_builder_add (&b, "{sv}", key,
          g_variant_new_string (lua_tostring (L, -1)));
      break;

    case LUA_TTABLE:
      g_variant_builder_add (&b, "{sv}", key, lua_to_gvariant (L, -1));
      break;

    default:
      wp_warning ("skipping bad component argument value");
      break;
    }

    lua_pop (L, 1);
  }

  return g_variant_builder_end (&b);
}

static gboolean
load_components (lua_State *L, WpCore * core, GError ** error)
{
  lua_getglobal (L, "SANDBOX_COMMON_ENV");

  switch (lua_getfield (L, -1, "components")) {
  case LUA_TTABLE:
    break;
  case LUA_TNIL:
    wp_debug ("no components specified");
    goto done;
  default:
    g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
        "Expected 'components' to be a table");
    return FALSE;
  }

  lua_pushnil (L);
  while (lua_next (L, -2)) {
    /* value must be a table */
    if (lua_type (L, -1) != LUA_TTABLE) {
      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
          "'components' must be a table with tables as values");
      return FALSE;
    }

    /* record indexes to the current key and value of the components table */
    int key = lua_absindex (L, -2);
    int table = lua_absindex (L, -1);

    /* get component */
    if (lua_geti (L, table, 1) != LUA_TSTRING) {
      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
          "components['%s'] has a non-string or unspecified component name",
          lua_tostring (L, key));
      return FALSE;
    }
    const char * component = lua_tostring (L, -1);

    /* get component type */
    if (lua_getfield (L, table, "type") != LUA_TSTRING) {
      g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_INVALID_ARGUMENT,
          "components['%s'] has a non-string or unspecified component type",
          lua_tostring (L, key));
      return FALSE;
    }
    const char * type = lua_tostring (L, -1);

    /* optional component arguments */
    GVariant *args = NULL;
    if (lua_getfield (L, table, "args") == LUA_TTABLE) {
      args = lua_to_gvariant (L, -1);
    }

    wp_debug ("load component: %s (%s)", component, type);

    if (!wp_core_load_component (core, component, type, args, error))
      return FALSE;

    /* clear the stack up to the key */
    lua_settop (L, key);
  }

done:
  lua_pop (L, 2); /* pop components & SANDBOX_COMMON_ENV */
  return TRUE;
}

gboolean
wp_lua_scripting_load_configuration (const gchar * conf_file,
    WpCore * core, GError ** error)
{
  g_autofree gchar * path = NULL;
  g_autoptr (lua_State) L = wplua_new ();
  gboolean found = FALSE;

  wplua_enable_sandbox (L, WP_LUA_SANDBOX_MINIMAL_STD);

  /* load conf_file itself */
  path = g_build_filename (wp_get_config_dir (), conf_file, NULL);
  if (g_file_test (path, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_REGULAR)) {
    wp_info ("loading config file: %s", path);
    if (!wplua_load_path (L, path, error))
      return FALSE;
    found = TRUE;
  }
  g_clear_pointer (&path, g_free);

  /* aggregate split files from the ${conf_file}.d subdirectory */
  path = g_strdup_printf ("%s" G_DIR_SEPARATOR_S "%s.d",
      wp_get_config_dir (), conf_file);
  if (g_file_test (path, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR)) {
    g_autoptr (GDir) conf_dir = g_dir_open (path, 0, error);
    if (!conf_dir)
      return FALSE;

    const gchar *filename = NULL;
    while ((filename = g_dir_read_name (conf_dir))) {
      /* Only parse files that have the proper extension */
      if (g_str_has_suffix (filename, ".lua")) {
        g_autofree gchar * file = g_build_filename (path, filename, NULL);
        wp_info ("loading config file: %s", file);
        if (!wplua_load_path (L, file, error))
          return FALSE;
        found = TRUE;
      }
    }
  }

  if (!found) {
    g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
        "Could not locate configuration file '%s'", conf_file);
    return FALSE;
  }

  if (!add_spa_libs (L, core, error))
    return FALSE;

  if (!load_components (L, core, error))
    return FALSE;

  return TRUE;
}