usermanager: Add back temporary is_admin to warn about deprecated API usage Goal: Introduce role-auth with minimal disruption is_admin() is unsafe in a system with per-session permissions, so it has been deprecated. Roll-out approach: 1) First, log a warning when is_admin() is used. It should continue to function normally, backed by the new role API. Nothing is really using per-session authz yet, so there is minimal security concern. The 'strict_deprecate_is_admin' global setting can be set to 'true' to force a hard failure of is_admin() attempts (it will log an error and always return false). 2) In some time (at least 1 week), but possibly longer depending on the number of affected deployments: switch 'strict_deprecate_is_admin' to 'true' by default. It can still be disabled for systems that need it. 3) Further in the future, before the next release, the option will be removed and is_admin() will be permanently disabled.

#include <lua.h>
#include <lauxlib.h>


static int lc_xpcall (lua_State *L) {
  int ret;
  int n_arg = lua_gettop(L);
  /* f, msgh, p1, p2... */
  luaL_argcheck(L, n_arg >= 2, 2, "value expected");
  lua_pushvalue(L, 1);  /* f to top */
  lua_pushvalue(L, 2);  /* msgh to top */
  lua_replace(L, 1); /* msgh to 1 */
  lua_replace(L, 2); /* f to 2 */
  /* msgh, f, p1, p2... */
  ret = lua_pcall(L, n_arg - 2, LUA_MULTRET, 1);
  lua_pushboolean(L, ret == 0);
  lua_replace(L, 1);
  return lua_gettop(L);
}

int luaopen_util_compat(lua_State *L) {
	lua_createtable(L, 0, 2);
	{
		lua_pushcfunction(L, lc_xpcall);
		lua_setfield(L, -2, "xpcall");
	}
	return 1;
}