lua.c

Go to the documentation of this file.

/*
 *   This program is is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License, version 2 if the
 *   License as published by the Free Software Foundation.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 512484de8948670daf8972da4476ce30b25aab4c $
 * @file lua.c
 * @brief Library functions for the lua module.
 *
 * @author Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 * @author Artur Malinowski (artur@wow.com)
 *
 * @copyright 2015 The FreeRADIUS Server Project.
 */
RCSID("$Id: 512484de8948670daf8972da4476ce30b25aab4c $")
 
#define LOG_PREFIX mctx->mi->name
 
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/util/debug.h>
 
#include "config.h"
#include "lua.h"
 
#include <float.h>
#include <lauxlib.h>
#include <lualib.h>
 
#define RLM_LUA_STACK_SET()     int _fr_lua_stack_state = lua_gettop(L)
#define RLM_LUA_STACK_RESET()   lua_settop(L, _fr_lua_stack_state)
 
typedef struct fr_lua_pair_s fr_lua_pair_t;
struct fr_lua_pair_s {
        fr_dict_attr_t const    *da;
        fr_pair_t               *vp;
        unsigned int            idx;
        fr_lua_pair_t           *parent;
};
 
static void _lua_pair_init(lua_State *L, fr_pair_t *vp, fr_dict_attr_t const *da, unsigned int idx, fr_lua_pair_t *parent);
 
DIAG_OFF(type-limits)
/** Convert fr_pair_ts to Lua values
 *
 * Pushes a Lua representation of an attribute value onto the stack.
 *
 * @param[in] request   The current request.
 * @param[in] L         Lua interpreter.
 * @param[in] vp        to convert.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int fr_lua_marshall(request_t *request, lua_State *L, fr_pair_t const *vp)
{
        if (!vp) return -1;
 
#if PTRDIFF_MAX < INT64_MAX
#define IN_RANGE_INTEGER_SIGNED(_x) \
        do { \
                if ((((int64_t)(_x)) < PTRDIFF_MIN) || (((int64_t)(_x)) > PTRDIFF_MAX)) { \
                        REDEBUG("Value (%" PRId64 ") cannot be represented as Lua integer.  Must be between %td-%td", \
                                (int64_t)(_x), (ptrdiff_t)PTRDIFF_MIN, (ptrdiff_t)PTRDIFF_MAX); \
                        return -1; \
                } \
        } while (0)
 
#define IN_RANGE_INTEGER_UNSIGNED(_x) \
        do { \
                if (((uint64_t)(_x)) > PTRDIFF_MAX) { \
                        REDEBUG("Value (%" PRIu64 ") cannot be represented as Lua integer.  Must be between 0-%td", \
                                (uint64_t)(_x), (ptrdiff_t)PTRDIFF_MAX); \
                        return -1; \
                } \
        } while (0)
#else
#define IN_RANGE_INTEGER_SIGNED(_x) \
        do { \
        } while (0)
 
#define IN_RANGE_INTEGER_UNSIGNED(_x) \
        do { \
        } while (0)
#endif
 
#define IN_RANGE_FLOAT_SIGNED(_x) \
        do { \
                if ((((double)(_x)) < DBL_MIN) || (((double)(_x)) > DBL_MAX)) { \
                        REDEBUG("Value (%f) cannot be represented as Lua number.  Must be between %f-%f", \
                                (double)(_x), DBL_MIN, DBL_MAX); \
                        return -1; \
                } \
        } while (0)
 
        switch (vp->vp_type) {
        case FR_TYPE_ETHERNET:
        case FR_TYPE_IPV4_ADDR:
        case FR_TYPE_IPV6_ADDR:
        case FR_TYPE_IPV4_PREFIX:
        case FR_TYPE_IPV6_PREFIX:
        case FR_TYPE_COMBO_IP_ADDR:
        case FR_TYPE_COMBO_IP_PREFIX:
        case FR_TYPE_IFID:
        case FR_TYPE_TIME_DELTA:
        {
                char    buff[128];
                ssize_t slen;
 
                slen = fr_pair_print_value_quoted(&FR_SBUFF_OUT(buff, sizeof(buff)), vp, T_BARE_WORD);
                if (slen < 0) {
                        REDEBUG("Cannot convert %s to Lua type, insufficient buffer space",
                                fr_type_to_str(vp->vp_type));
                        return -1;
                }
 
                lua_pushlstring(L, buff, (size_t)slen);
        }
                break;
 
        case FR_TYPE_STRING:
                lua_pushlstring(L, vp->vp_strvalue, vp->vp_length);
                break;
 
        case FR_TYPE_OCTETS:
                lua_pushlstring(L, (char const *)vp->vp_octets, vp->vp_length); /* lstring variant is embedded NULL safe */
                break;
 
        case FR_TYPE_BOOL:
                lua_pushinteger(L, (lua_Integer)(vp->vp_bool ? 1 : 0));
                break;
 
        case FR_TYPE_UINT8:
                lua_pushinteger(L, (lua_Integer)vp->vp_uint8);
                break;
 
        case FR_TYPE_UINT16:
                lua_pushinteger(L, (lua_Integer)vp->vp_uint16);
                break;
 
        case FR_TYPE_UINT32:
                lua_pushinteger(L, (lua_Integer)vp->vp_uint32);
                break;
 
        case FR_TYPE_UINT64:
                IN_RANGE_INTEGER_UNSIGNED(vp->vp_uint64);
                lua_pushinteger(L, (lua_Integer)vp->vp_uint64);
                break;
 
        case FR_TYPE_INT8:
                lua_pushinteger(L, (lua_Integer)vp->vp_int8);
                break;
 
        case FR_TYPE_INT16:
                lua_pushinteger(L, (lua_Integer)vp->vp_int16);
                break;
 
        case FR_TYPE_INT32:
                lua_pushinteger(L, (lua_Integer)vp->vp_int32);
                break;
 
        case FR_TYPE_INT64:
                IN_RANGE_INTEGER_SIGNED(vp->vp_int64);
                lua_pushinteger(L, (lua_Integer)vp->vp_int64);
                break;
 
        case FR_TYPE_DATE:
                lua_pushinteger(L, (lua_Integer) fr_unix_time_to_sec(vp->vp_date));
                break;
 
        case FR_TYPE_FLOAT32:
                IN_RANGE_FLOAT_SIGNED(vp->vp_float32);
                lua_pushnumber(L, (lua_Number)vp->vp_float32);
                break;
 
        case FR_TYPE_FLOAT64:
                IN_RANGE_FLOAT_SIGNED(vp->vp_float64);
                lua_pushnumber(L, (lua_Number)vp->vp_float64);
                break;
 
        case FR_TYPE_SIZE:
                IN_RANGE_INTEGER_UNSIGNED(vp->vp_size);
                lua_pushinteger(L, (lua_Integer)vp->vp_size);
                break;
 
        case FR_TYPE_NON_LEAF:
                REDEBUG("Cannot convert %s to Lua type", fr_type_to_str(vp->vp_type));
                return -1;
        }
        return 0;
}
DIAG_ON(type-limits)
 
/** Use Lua values to populate a fr_value_box_t
 *
 * Convert Lua values to fr_value_box_t.  How the Lua value is converted is dependent
 * on the type of the box.
 *
 * @param[in] ctx       To allocate new fr_pair_t in.
 * @param[out] out_vb   Value box to populate.
 * @param[in] request   the current request.
 * @param[in] L         Lua interpreter.
 * @param[in] da        specifying the type of attribute the box represent.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int fr_lua_unmarshall(TALLOC_CTX *ctx, fr_value_box_t *out_vb, request_t *request,
                             lua_State *L, fr_dict_attr_t const *da)
{
        switch (lua_type(L, -1)) {
        case LUA_TNUMBER:
        {
                fr_value_box_t  vb;
 
                /*
                 *      lua_tonumber actually returns ptrdiff_t
                 *      so we need to check if our input box
                 *      type is the same width or greater.
                 */
                static_assert(SIZEOF_MEMBER(fr_value_box_t, vb_int64) >= sizeof(ptrdiff_t),
                              "fr_value_box_t field smaller than return from lua_tointeger");
 
                static_assert(SIZEOF_MEMBER(fr_value_box_t, vb_float64) >= sizeof(double),
                              "fr_value_box_t field smaller than return from lua_tonumber");
 
                switch (da->type) {
                /*
                 *      Preserve decimal precision.
                 *
                 *      Our FR_TYPE_FLOAT64 is a double, which is apparently
                 *      what lua_tonumber returns on most platforms.
                 */
                case FR_TYPE_FLOAT32:
                case FR_TYPE_FLOAT64:
                        fr_value_box_init(&vb, FR_TYPE_FLOAT64, NULL, true);
                        vb.vb_float64 = lua_tonumber(L, -1);
                        break;
 
                default:
                        fr_value_box_init(&vb, FR_TYPE_INT64, NULL, true);
                        vb.vb_int64 = lua_tointeger(L, -1);
                        break;
                }
 
 
                if (fr_value_box_cast(ctx, out_vb, da->type, da, &vb) < 0) {
                        RPEDEBUG("Failed unmarshalling Lua number for \"%s\"", da->name);
                        return -1;
                }
        }
                break;
 
        case LUA_TSTRING:
        {
                fr_value_box_t  vb;
                char const      *p;
                size_t          len;
 
                p = (char const *)lua_tolstring(L, -1, &len);
                if (!p) {
                        REDEBUG("Unmarshalling failed, Lua bstring was NULL");
                        return -1;
                }
 
                fr_value_box_bstrndup_shallow(&vb, NULL, p, len, true);
 
                if (fr_value_box_cast(ctx, out_vb, da->type, da, &vb) < 0) {
                        RPEDEBUG("Failed unmarshalling Lua string for \"%s\"", da->name);
                        return -1;
                }
        }
                break;
 
        case LUA_TLIGHTUSERDATA:
        case LUA_TUSERDATA:
        {
                size_t len;
                uint8_t *p;
 
                len = lua_objlen(L, -1);
                if (len == 0) {
                        REDEBUG("Unmarshalling failed, can't determine length of user data");
                        return -1;
                }
                p = lua_touserdata(L, -1);
                if (!p) {
                        REDEBUG("Unmarshalling failed, user data was NULL");
                }
                fr_value_box_memdup(ctx, out_vb, da, p, len, true);
        }
                break;
 
        default:
        {
                int type = lua_type(L, -1);
                REDEBUG("Unmarshalling failed, unsupported Lua type %s (%i)", lua_typename(L, type), type);
 
                return -1;
        }
        }
 
        return 0;
}
 
/** Build parent structural pairs needed when a leaf node is set
 *
 */
static int fr_lua_pair_parent_build(request_t *request, fr_lua_pair_t *pair_data)
{
        if (!pair_data->parent->vp) {
                if (fr_lua_pair_parent_build(request, pair_data->parent) < 0) return -1;
        }
        if (pair_data->idx > 1) {
                unsigned int count = fr_pair_count_by_da(&pair_data->parent->vp->vp_group, pair_data->da);
                if (count < (pair_data->idx - 1)) {
                        RERROR("Attempt to set instance %d when only %d exist", pair_data->idx, count);
                        return -1;
                }
        }
 
        if (fr_pair_append_by_da(pair_data->parent->vp, &pair_data->vp,
                                 &pair_data->parent->vp->vp_group, pair_data->da) < 0) return -1;
        return 0;
}
 
/** Set an instance of an attribute
 *
 * @note Should only be present in the Lua environment as a closure.
 * @note Takes one upvalue - the fr_lua_pair_t representing this pair as user data.
 * @note Is called as an __newindex metamethod, so takes the table (can be ignored),
 *       the field (an integer index value) and the new value.
 *
 * @param[in] L Lua state.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int _lua_pair_setter(lua_State *L)
{
        request_t               *request = fr_lua_util_get_request();
        fr_lua_pair_t           *pair_data, *parent;
        fr_dict_attr_t const    *da;
        fr_pair_t               *vp;
        lua_Integer             index;
 
        if (!lua_isnumber(L, -2)) {
                RERROR("Attempt to %s attribute \"%s\" table.", lua_isnil(L, -1) ? "delete" : "set value on", lua_tostring(L, -2));
                RWARN("Values should be manipulated using <list>['<attr>'][idx] = <value> where idx is the attribute instance (starting at 1)");
                return -1;
        }
 
        index = lua_tointeger(L, -2);
        if (index < 1) {
                RERROR("Invalid attribute index %ld", index);
                return -1;
        }
 
        pair_data = lua_touserdata(L, lua_upvalueindex(1));
        da = pair_data->da;
 
        if (!fr_type_is_leaf(da->type)) {
                RERROR("Values cannot be assigned to structural attribute \"%s\"", da->name);
                return -1;
        }
        parent = pair_data->parent;
 
        /*
         *      If the value of the Lua stack was nil, we delete the attribute if it exists.
         */
        if (lua_isnil(L, -1)) {
                if (!pair_data->parent->vp) return 0;
                vp = fr_pair_find_by_da_idx(&parent->vp->vp_group, da, index - 1);
                if (!vp) return 0;
                if (pair_data->vp == vp) pair_data->vp = NULL;
                fr_pair_delete(&parent->vp->vp_group, vp);
                return 0;
        }
 
        if (!parent->vp) {
                if (fr_lua_pair_parent_build(request, parent) < 0) return -1;
        }
 
        vp = fr_pair_find_by_da_idx(&parent->vp->vp_group, da, index - 1);
 
        /*
         *      Asked to add a pair we don't have - check we're not being asked
         *      to add a gap.
         */
        if (!vp && (index > 1)) {
                unsigned int count = fr_pair_count_by_da(&parent->vp->vp_group, da);
                if (count < (index - 1)) {
                        RERROR("Attempt to set instance %ld when only %d exist", index, count);
                        return -1;
                }
        }
 
        if (!vp) {
                if (fr_pair_append_by_da(parent->vp, &vp, &parent->vp->vp_group, da) < 0) {
                        RERROR("Failed to create attribute %s", da->name);
                        return -1;
                }
        }
        if (fr_lua_unmarshall(vp, &vp->data, request, L, da) < 0) return -1;
 
        return 0;
}
 
/** Iterate over instances of a leaf attribute
 *
 * Each call returns with the value of the next instance of the attribute
 * on the Lua stack, or nil, when there are no more instances.
 *
 */
static int _lua_pair_iterator(lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
        fr_dcursor_t    *cursor;
        fr_pair_t       *vp;
 
        fr_assert(lua_isuserdata(L, lua_upvalueindex(1)));
 
        cursor = lua_touserdata(L, lua_upvalueindex(1));
        fr_assert(cursor);
 
        vp = fr_dcursor_current(cursor);
        if (!vp) {
                lua_pushnil(L);
                return 1;
        }
 
        if (fr_lua_marshall(request, L, vp) < 0) return -1;
 
        fr_dcursor_next(cursor);
        return 1;
}
 
/** Initiate an iterator to return all the values of a given attribute
 *
 */
static int _lua_pair_iterator_init(lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
        fr_dcursor_t    *cursor;
        fr_lua_pair_t   *pair_data;
 
        fr_assert(lua_isuserdata(L, lua_upvalueindex(1)));
        pair_data = lua_touserdata(L, lua_upvalueindex(1));
        fr_assert(pair_data);
 
        cursor = (fr_dcursor_t*) lua_newuserdata(L, sizeof(fr_dcursor_t));
        if (!cursor) {
                REDEBUG("Failed allocating user data to hold cursor");
                return -1;
        }
        fr_pair_dcursor_by_da_init(cursor, &pair_data->parent->vp->vp_group, pair_data->da);
 
        lua_pushcclosure(L, _lua_pair_iterator, 1);
 
        return 1;
}
 
/** Iterate over attributes in a list
 *
 * Each call returns with two values on the Lua stack
 *  - the name of the next attribute
 *  - the value of the next attribute, or an array of child attribute names
 *
 * or, nil is pushed to the stack when there are no more attributes in the list.
 */
static int _lua_list_iterator(lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
        fr_dcursor_t    *cursor;
        fr_pair_t       *vp;
 
        fr_assert(lua_isuserdata(L, lua_upvalueindex(1)));
 
        cursor = lua_touserdata(L, lua_upvalueindex(1));
        fr_assert(cursor);
 
        vp = fr_dcursor_current(cursor);
        if(!vp) {
                lua_pushnil(L);
                return 1;
        }
 
        lua_pushstring(L, vp->da->name);
 
        /*
         *      For structural attributes return an array of the child names
         */
        if (fr_type_is_structural(vp->da->type)) {
                fr_pair_t       *child = NULL;
                unsigned int    i = 1;
 
                lua_createtable(L, fr_pair_list_num_elements(&vp->vp_group), 0);
                while ((child = fr_pair_list_next(&vp->vp_group, child))) {
                        lua_pushstring(L, child->da->name);
                        lua_rawseti(L, -2, i++);
                }
        } else {
                if (fr_lua_marshall(request, L, vp) < 0) return -1;
        }
 
        fr_dcursor_next(cursor);
 
        return 2;
}
 
/** Initialise a new structural iterator
 *
 */
static int _lua_list_iterator_init(lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
        fr_dcursor_t    *cursor;
        fr_lua_pair_t   *pair_data;
 
        fr_assert(lua_isuserdata(L, lua_upvalueindex(1)));
        pair_data = lua_touserdata(L, lua_upvalueindex(1));
        if (!pair_data->vp) return 0;
 
        cursor = (fr_dcursor_t*) lua_newuserdata(L, sizeof(fr_dcursor_t));
        if (!cursor) {
                REDEBUG("Failed allocating user data to hold cursor");
                return -1;
        }
        fr_pair_dcursor_init(cursor, &pair_data->vp->vp_group);
 
        lua_pushcclosure(L, _lua_list_iterator, 1);
 
        return 1;
}
 
/** Get an attribute or an instance of an attribute
 *
 * When called with a numeric index, it is the instance of the attribute
 * which is being requested.
 * Otherwise, the index is an attribute name.
 *
 * @note Should only be present in the Lua environment as a closure.
 * @note Takes one upvalue - the fr_lua_pair_t representing either this
 *       attribute in the case it is an index being requested, or the
 *       parent in the case an attribute is being requested.
 * @note Is called as an __index metamethod, so takes the table (can be ignored)
 *       and the field (integer index for instance or string for attribute)
 *
 * @param[in] L Lua interpreter.
 * @return
 *      - -1 on failure.
 *      - 0 (no results) on success.
 *      - 1 on success with:
 *        - the fr_pair_t value on the stack for leaf values.
 *        - a lua table for structural items.
 */
static int _lua_pair_accessor(lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
        fr_lua_pair_t   *pair_data;
        fr_pair_t       *vp = NULL;
 
        fr_assert(lua_isuserdata(L, lua_upvalueindex(1)));
 
        pair_data = (fr_lua_pair_t *)lua_touserdata(L, lua_upvalueindex(1));
 
        if (lua_isnumber(L, -1)) {
                lua_Integer     index = lua_tointeger(L, -1);
 
                if (index < 1) {
                        RERROR("Invalid attribute index %ld", index);
                        return -1;
                }
 
                if (!pair_data->parent || !pair_data->parent->vp) return 0;
 
                if (index == 1 && pair_data->vp) {
                        vp = pair_data->vp;
                } else {
                        // Lua array indexes are 1 based, not 0 based.
                        vp = fr_pair_find_by_da_idx(&pair_data->parent->vp->vp_group, pair_data->da, index - 1);
                        if (index == 1) pair_data->vp = vp;
                }
                /*
                 *      Retrieving an instance of a leaf gives the actual attribute
                 *      value (if it exists)
                 */
                if (fr_type_is_leaf(pair_data->da->type)) {
                        if (!vp) return 0;
                        if (fr_lua_marshall(request, L, vp) < 0) return -1;
                        return 1;
                }
 
                fr_assert(fr_type_is_structural(pair_data->da->type));
 
                /*
                 *      Retrieving a structural attribute returns a new table.
                 */
                lua_newtable(L);
                _lua_pair_init(L, vp, pair_data->da, index, pair_data->parent);
 
        } else {
                fr_dict_attr_t const    *da;
                char const              *attr = lua_tostring(L, -1);
 
                if (!attr) {
                        RERROR("Failed retrieving field name from lua stack");
                        return -1;
                }
 
                da = fr_dict_attr_by_name(NULL, pair_data->da, attr);
 
                /*
                 *      Allow fallback to internal attributes if the parent is a group or dictionary root.
                 */
                if (!da && (fr_type_is_group(pair_data->da->type) || pair_data->da->flags.is_root)) {
                        da = fr_dict_attr_by_name(NULL, fr_dict_root(fr_dict_internal()), attr);
                }
 
                if (!da) {
                        RERROR("Unknown or invalid attribute name \"%s\"", attr);
                        return -1;
                }
 
                if (pair_data->vp) vp = fr_pair_find_by_da(&pair_data->vp->vp_group, NULL, da);
                _lua_pair_init(L, vp, da, 1, pair_data);
 
                lua_rawset(L, -3);              /* Cache the attribute manipulation object */
                lua_getfield(L, -1, attr);      /* and return it */
        }
 
        return 1;
}
 
/** Check whether the Lua interpreter were actually linked to is LuaJIT
 *
 * @param L Lua interpreter.
 * @return true if were running with LuaJIT else false.
 */
bool fr_lua_isjit(lua_State *L)
{
        bool ret = false;
        RLM_LUA_STACK_SET();
        lua_getglobal(L, "jit");
        if (lua_isnil(L, -1)) goto done;
 
        ret = true;
done:
        RLM_LUA_STACK_RESET();
 
        return ret;
}
 
char const *fr_lua_version(lua_State *L)
{
        char const *version;
 
        RLM_LUA_STACK_SET();
        lua_getglobal(L, "jit");
        if (!lua_isnil(L, -1)) {
                lua_getfield(L, -1, "version"); /* Version field in jit table */
        } else {
                lua_getglobal(L, "_VERSION");   /* Version global */
        }
 
        if (lua_isnil(L, -1) || !(version = lua_tostring(L, -1))) {
                return "unknown version";
        }
        RLM_LUA_STACK_RESET();
 
        return version;
}
 
/** Check if a given function was loaded into an index in the global table
 *
 * Also check what was loaded there is a function and that it accepts the correct arguments.
 *
 * @param[in] mctx              module instantiation data.
 * @param[in] L                 the lua state.
 * @param[in] name              of function to check.
 * @returns 0 on success (function is present and correct), or -1 on failure.
 */
int fr_lua_check_func(module_inst_ctx_t const *mctx, lua_State *L, char const *name)
{
        int ret;
        int type;
 
        RLM_LUA_STACK_SET();
 
        if (name == NULL) return 0;
 
        lua_getglobal(L, name);
 
        /*
         *      Check the global is a function.
         */
        type = lua_type(L, -1);
        switch (type) {
        case LUA_TFUNCTION:
                break;
 
        case LUA_TNIL:
                ERROR("Function \"%s\" not found ", name);
                ret = -1;
                goto done;
 
        default:
                ERROR("Value found at index \"%s\" is not a function (is a %s)", name, lua_typename(L, type));
                ret = -1;
                goto done;
        }
        ret = 0;
done:
        RLM_LUA_STACK_RESET();
        return ret;
}
 
/** Resolve a path string to a field value in Lua
 *
 * Parses a string in the format
 * @verbatim obj0[.obj1][.objN] @endverbatim, adding all tables it traverses
 * to the stack.
 *
 * All paths are assumed to start at a global, so the first field
 * will be looked up in the global table.
 *
 */
static int fr_lua_get_field(lua_State *L, request_t *request, char const *field)
{
        char buff[512];
        char const *p = field, *q;
 
        q = strchr(p, '.');
        if (!q) {       /* No field, just global */
                lua_getglobal(L, p);
                if (lua_isnil(L, -1)) {
                does_not_exist:
                        REMARKER(field, p - field, "Field does not exist");
                        return -1;
                }
                return 0;
        }
 
        if ((size_t) (q - p) >= sizeof(buff)) {
        too_long:
                REDEBUG("Field name too long, expected < %zu, got %zu", q - p, sizeof(buff));
                return -1;
        }
 
        strlcpy(buff, p, (q - p) + 1);
        lua_getglobal(L, buff);
        if (lua_isnil(L, -1)) goto does_not_exist;
        p = q + 1;      /* Skip the '.' */
 
        while ((q = strchr(p, '.'))) {
                if ((size_t) (q - p) >= sizeof(buff)) goto too_long;
 
                strlcpy(buff, p, (q - p) + 1);
                lua_getfield(L, -1, buff);
                if (lua_isnil(L, -1)) goto does_not_exist;
                p = q + 1;
        }
 
        lua_getfield(L, -1, p);
        if (lua_isnil(L, -1)) goto does_not_exist;
 
        return 0;
}
 
/** Initialise a table representing a pair
 *
 * After calling this function, a new table will be on the lua stack which represents the pair.
 *
 * The pair may not exist - e.g. when setting a new nested attribute, parent pairs may not
 * have been created yet.  In that case, this holds the da and index of the instance which
 * will be created when the leaf is assigned a value.
 *
 * @param[in] L         the lua state
 * @param[in] vp        the actual pair instance being represented, if it already exists
 * @param[in] da        dictionary attribute for this pair
 * @param[in] idx       index of the attribute instance (starting at 1)
 * @param[in] parent    lua userdata for the parent of this attribute.
 */
static void _lua_pair_init(lua_State *L, fr_pair_t *vp, fr_dict_attr_t const *da, unsigned int idx, fr_lua_pair_t *parent)
{
        fr_lua_pair_t   *pair_data;
 
        lua_newtable(L);
 
        /*
         *      The userdata associated with the meta functions
         *      __index and __newindex, and the .pairs() field.
         */
        pair_data = lua_newuserdata(L, sizeof(fr_lua_pair_t));
        *pair_data = (fr_lua_pair_t) {
                .da = da,
                .idx = idx,
                .vp = vp,
                .parent = parent
        };
        if (fr_type_is_structural(da->type)) {
                lua_pushcclosure(L, _lua_list_iterator_init, 1);
        } else {
                lua_pushcclosure(L, _lua_pair_iterator_init, 1);
        }
        lua_setfield(L, -2, "pairs");
 
        lua_newtable(L);        /* Metatable for index functions*/
 
        lua_pushlightuserdata(L, pair_data);
        lua_pushcclosure(L, _lua_pair_accessor, 1);
        lua_setfield(L, -2, "__index");
 
        lua_pushlightuserdata(L, pair_data);
        lua_pushcclosure(L, _lua_pair_setter, 1);
        lua_setfield(L, -2, "__newindex");
        lua_setmetatable(L, -2);
}
 
static void _lua_fr_request_register(lua_State *L, request_t *request)
{
        /* fr = {} */
        lua_getglobal(L, "fr");
        luaL_checktype(L, -1, LUA_TTABLE);
 
        /* fr = { request {} } */
        lua_pushstring(L, "request");
        _lua_pair_init(L, fr_pair_list_parent(&request->request_pairs), fr_dict_root(request->proto_dict), 1, NULL);
        lua_rawset(L, -3);
 
        lua_pushstring(L, "reply");
        _lua_pair_init(L, fr_pair_list_parent(&request->reply_pairs), fr_dict_root(request->proto_dict), 1, NULL);
        lua_rawset(L, -3);
 
        lua_pushstring(L, "control");
        _lua_pair_init(L, fr_pair_list_parent(&request->control_pairs), fr_dict_root(request->proto_dict), 1, NULL);
        lua_rawset(L, -3);
 
        lua_pushstring(L, "session-state");
        _lua_pair_init(L, fr_pair_list_parent(&request->session_state_pairs), fr_dict_root(request->proto_dict), 1, NULL);
        lua_rawset(L, -3);
}
 
unlang_action_t fr_lua_run(rlm_rcode_t *p_result, module_ctx_t const *mctx, request_t *request, char const *funcname)
{
        rlm_lua_thread_t        *thread = talloc_get_type_abort(mctx->thread, rlm_lua_thread_t);
        lua_State               *L = thread->interpreter;
        rlm_rcode_t             rcode = RLM_MODULE_OK;
 
        fr_lua_util_set_mctx(mctx);
        fr_lua_util_set_request(request);
 
        ROPTIONAL(RDEBUG2, DEBUG2, "Calling %s() in interpreter %p", funcname, L);
 
        if (request) _lua_fr_request_register(L, request);
 
        /*
         *      Get the function were going to be calling
         */
        if (fr_lua_get_field(L, request, funcname) < 0) {
error:
                fr_lua_util_set_mctx(NULL);
                fr_lua_util_set_request(NULL);
 
                RETURN_MODULE_FAIL;
        }
 
        if (!lua_isfunction(L, -1)) {
                int type = lua_type(L, -1);
 
                ROPTIONAL(RDEBUG2, DEBUG2, "'%s' is not a function, is a %s (%i)", funcname, lua_typename(L, type), type);
                goto error;
        }
 
        if (lua_pcall(L, 0, 1, 0) != 0) {
                char const *msg = lua_tostring(L, -1);
 
                ROPTIONAL(RDEBUG2, DEBUG2, "Call to %s failed: %s", funcname, msg ? msg : "unknown error");
                goto error;
        }
 
        /*
         *      functions without rcodeurn or rcodeurning none/nil will be RLM_MODULE_OK
         */
        if (!lua_isnoneornil(L, -1)) {
                /*
                 *      e.g: rcodeurn 2, rcodeurn "2", rcodeurn fr.handled, fr.fail, ...
                 */
                if (lua_isnumber(L, -1)) {
                        rcode = lua_tointeger(L, -1);
                        if (fr_table_str_by_value(rcode_table, rcode, NULL) != NULL) goto done;
                }
 
                /*
                 *      e.g: rcodeurn "handled", "ok", "fail", ...
                 */
                if (lua_isstring(L, -1)) {
                        rcode = fr_table_value_by_str(rcode_table, lua_tostring(L, -1), -1);
                        if ((int)rcode != -1) goto done;
                }
 
                ROPTIONAL(RDEBUG2, DEBUG2, "Lua function %s() rcodeurned invalid rcode \"%s\"", funcname, lua_tostring(L, -1));
                goto error;
        }
 
done:
        fr_lua_util_set_mctx(NULL);
        fr_lua_util_set_request(NULL);
 
        RETURN_MODULE_RCODE(rcode);
}
 
/*
 *      Initialise the table "fr." with all valid return codes.
 */
static int _lua_rcode_table_newindex(UNUSED lua_State *L)
{
        request_t       *request = fr_lua_util_get_request();
 
        RWDEBUG("You can't modify the table 'fr.rcode.{}' (read-only)");
 
        return 1;
}
 
static int _lua_rcode_table_index(lua_State *L)
{
        char const *key = lua_tostring(L, -1);
        int ret;
 
        ret = fr_table_value_by_str(rcode_table, key, -1);
        if (ret != -1) {
                lua_pushinteger(L, ret);
                return 1;
        }
 
        lua_pushfstring(L, "The fr.rcode.%s is not found", key);
        return -1;
}
 
/*
 *      As can be seen in http://luajit.org/extensions.html, the pairs() is disabled by default.
 *      ps: We add pairs() method just to inform the user that it does not work.
 */
static int _lua_rcode_table_pairs(lua_State *L)
{
        lua_pushfstring(L, "The pairs(fr.rcode) is not available. Access directly! e.g: 'fr.rcode.reject'");
        return -1;
}
 
static void fr_lua_rcode_register(lua_State *L, char const *name)
{
        const luaL_Reg metatable[] = {
                { "__index",    _lua_rcode_table_index },
                { "__newindex", _lua_rcode_table_newindex },
                { "__pairs",    _lua_rcode_table_pairs },
#ifdef HAVE_LUAJIT_H
                { "pairs",      _lua_rcode_table_pairs },
#endif
                { NULL, NULL }
        };
 
        /* fr = {} */
        lua_getglobal(L, "fr");
        luaL_checktype(L, -1, LUA_TTABLE);
 
        /* fr = { rcode = {} } */
        lua_newtable(L);
        {
                luaL_register(L, name, metatable);
                lua_setmetatable(L, -2);
                lua_setfield(L, -2, name);
        }
}
 
/** Initialise a new Lua/LuaJIT interpreter
 *
 * Creates a new lua_State and verifies all required functions have been loaded correctly.
 *
 * @param[in] out       Where to write a pointer to the new state.
 * @param[in] mctx      configuration data for the
 * @return 0 on success else -1.
 */
int fr_lua_init(lua_State **out, module_inst_ctx_t const *mctx)
{
        rlm_lua_t const         *inst = talloc_get_type_abort_const(mctx->mi->data, rlm_lua_t);
        lua_State               *L;
 
        fr_lua_util_set_mctx(MODULE_CTX_FROM_INST(mctx));
 
        L = luaL_newstate();
        if (!L) {
                ERROR("Failed initialising Lua state");
                return -1;
        }
 
        luaL_openlibs(L);
 
        /*
         *      Load the Lua file into our environment.
         */
        if (luaL_loadfile(L, inst->module) != 0) {
                ERROR("Failed loading file: %s", lua_gettop(L) ? lua_tostring(L, -1) : "Unknown error");
 
        error:
                *out = NULL;
                fr_lua_util_set_mctx(NULL);
                lua_close(L);
                return -1;
        }
 
        if (lua_pcall(L, 0, LUA_MULTRET, 0) != 0) {
                ERROR("Failed executing script: %s", lua_gettop(L) ? lua_tostring(L, -1) : "Unknown error");
 
                goto error;
        }
 
        /*
         *      Setup "fr.{}"
         */
        fr_lua_util_fr_register(L);
 
        /*
         *      Setup "fr.log.{}"
         */
        if (inst->jit) {
                DEBUG4("Initialised new LuaJIT interpreter %p", L);
                if (fr_lua_util_jit_log_register(L) < 0) goto error;
        } else {
                DEBUG4("Initialised new Lua interpreter %p", L);
                if (fr_lua_util_log_register(L) < 0) goto error;
        }
 
        /*
         *      Setup the "fr.rcode.{}"  with all RLM_MODULE_*
         *      e.g: "fr.rcode.reject", "fr.rcode.ok", ...
         */
        fr_lua_rcode_register(L, "rcode");
 
        /*
         *      Verify all the functions were provided.
         */
        if (fr_lua_check_func(mctx, L, inst->func_instantiate)
            || fr_lua_check_func(mctx, L, inst->func_detach)
            || fr_lua_check_func(mctx, L, inst->func_xlat)) {
                goto error;
        }
 
        *out = L;
        return 0;
}