condition.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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: e80621626ea115e377d64fe04d5e36021be4afbf $
 *
 * @file unlang/condition.c
 * @brief Unlang "condition" keyword evaluation.
 *
 * @copyright 2006-2019 The FreeRADIUS server project
 */
RCSID("$Id: e80621626ea115e377d64fe04d5e36021be4afbf $")
 
#include "condition_priv.h"
#include "group_priv.h"
 
typedef struct {
        fr_value_box_list_t     out;                            //!< Head of the result of a nested
                                                                ///< expansion.
        unlang_result_t         result;                         //!< Store the result of unlang expressions.
} unlang_frame_state_cond_t;
 
static unlang_action_t unlang_if_resume(unlang_result_t *p_result, request_t *request, unlang_stack_frame_t *frame)
{
        unlang_frame_state_cond_t       *state = talloc_get_type_abort(frame->state, unlang_frame_state_cond_t);
        fr_value_box_t                  *box = fr_value_box_list_head(&state->out);
        bool                            value;
 
        /*
         *      Something in the conditional evaluation failed.
         */
        if (state->result.rcode == RLM_MODULE_FAIL) {
                unlang_group_t *g = unlang_generic_to_group(frame->instruction);
                unlang_cond_t  *gext = unlang_group_to_cond(g);
 
                RDEBUG2("... failed to evaluate condition ...");
 
                if (!gext->has_else) RETURN_UNLANG_FAIL;
                return UNLANG_ACTION_EXECUTE_NEXT;
        }
 
        if (!box) {
                value = false;
 
        } else if (fr_value_box_list_next(&state->out, box) != NULL) {
                value = true;
 
        } else {
                value = fr_value_box_is_truthy(box);
        }
 
        if (!value) {
                RDEBUG2("...");
                return UNLANG_ACTION_EXECUTE_NEXT;
        }
 
        /*
         *      Tell the main interpreter to skip over the else /
         *      elsif blocks, as this "if" condition was taken.
         */
        while (frame->next &&
               ((frame->next->type == UNLANG_TYPE_ELSE) ||
                (frame->next->type == UNLANG_TYPE_ELSIF))) {
                frame->next = frame->next->next;
        }
 
        /*
         *      We took the "if".  Go recurse into its' children.
         */
        return unlang_group(p_result, request, frame);
}
 
static unlang_action_t unlang_if(unlang_result_t *p_result, request_t *request, unlang_stack_frame_t *frame)
{
        unlang_group_t                  *g = unlang_generic_to_group(frame->instruction);
        unlang_cond_t                   *gext = unlang_group_to_cond(g);
        unlang_frame_state_cond_t       *state = talloc_get_type_abort(frame->state, unlang_frame_state_cond_t);
 
        fr_assert(gext->head != NULL);
 
        /*
         *      If we always run this condition, then don't bother pushing anything onto the stack.
         *
         *      We still run this condition, even for "false" values, due to things like
         *
         *              if (0) { ... } elsif ....
         */
        if (gext->is_truthy) {
                return unlang_group(p_result, request, frame);
        }
 
        frame_repeat(frame, unlang_if_resume);
 
        fr_value_box_list_init(&state->out);
 
        if (unlang_xlat_push(state, &state->result, &state->out,
                             request, gext->head, UNLANG_SUB_FRAME) < 0) return UNLANG_ACTION_FAIL;
 
        return UNLANG_ACTION_PUSHED_CHILD;
}
 
void unlang_condition_init(void)
{
        unlang_register(UNLANG_TYPE_IF,
                           &(unlang_op_t){
                                .name = "if",
                                .interpret = unlang_if,
                                .flag = UNLANG_OP_FLAG_DEBUG_BRACES,
                                .frame_state_size = sizeof(unlang_frame_state_cond_t),
                                .frame_state_type = "unlang_frame_state_cond_t",
                           });
 
        unlang_register(UNLANG_TYPE_ELSE,
                           &(unlang_op_t){
                                .name = "else",
                                .flag = UNLANG_OP_FLAG_DEBUG_BRACES,
                                .interpret = unlang_group
                           });
 
        unlang_register(UNLANG_TYPE_ELSIF,
                           &(unlang_op_t){
                                .name = "elseif",
                                .interpret = unlang_if,
                                .flag = UNLANG_OP_FLAG_DEBUG_BRACES,
                                .frame_state_size = sizeof(unlang_frame_state_cond_t),
                                .frame_state_type = "unlang_frame_state_cond_t",
                           });
}