filterx-eval.c

/*
 * Copyright (c) 2023 Balazs Scheidler <balazs.scheidler@axoflow.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * As an additional exemption you are allowed to compile & link against the
 * OpenSSL libraries as published by the OpenSSL project. See the file
 * COPYING for details.
 *
 */
#include "filterx/filterx-eval.h"
#include "filterx/filterx-error.h"
#include "filterx/filterx-expr.h"
#include "logpipe.h"
#include "scratch-buffers.h"
#include "tls-support.h"

TLS_BLOCK_START
{
  FilterXEvalContext *eval_context;
}
TLS_BLOCK_END;

#define eval_context __tls_deref(eval_context)

FilterXEvalContext *
filterx_eval_get_context(void)
{
  return eval_context;
}

FilterXScope *
filterx_eval_get_scope(void)
{
  if (eval_context)
    return eval_context->scope;
  return NULL;
}

void
filterx_eval_set_context(FilterXEvalContext *context)
{
  eval_context = context;
}

void
filterx_eval_push_error(const gchar *message, FilterXExpr *expr, FilterXObject *object)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  if (context)
    {
      filterx_error_clear(&context->error);
      filterx_error_set_values(&context->error, message, expr, object);
    }
}

/* takes ownership of info */
void
filterx_eval_push_error_info(const gchar *message, FilterXExpr *expr, gchar *info, gboolean free_info)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  if (context)
    {
      filterx_error_clear(&context->error);
      filterx_error_set_values(&context->error, message, expr, NULL);
      filterx_error_set_info(&context->error, info, free_info);
    }
  else
    {
      if (free_info)
        g_free(info);
    }
}

void
filterx_eval_clear_errors(void)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  filterx_error_clear(&context->error);
}

const gchar *
filterx_eval_get_last_error(void)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  return context->error.message;
}

EVTTAG *
filterx_format_last_error(void)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  return filterx_error_format(&context->error);
}

EVTTAG *
filterx_format_last_error_location(void)
{
  FilterXEvalContext *context = filterx_eval_get_context();

  return filterx_error_format_location(&context->error);
}

FilterXEvalResult
filterx_eval_exec(FilterXEvalContext *context, FilterXExpr *expr, LogMessage *msg)
{
  context->msgs = &msg;
  context->num_msg = 1;
  FilterXEvalResult result = FXE_FAILURE;

  FilterXObject *res = filterx_expr_eval(expr);
  if (!res)
    {
      msg_debug("FILTERX ERROR",
                filterx_format_last_error_location(),
                filterx_format_last_error());
      filterx_eval_clear_errors();
      goto fail;
    }

  if (G_UNLIKELY(context->eval_control_modifier == FXC_DROP))
    result = FXE_DROP;
  else if (filterx_object_truthy(res))
    result = FXE_SUCCESS;
  filterx_object_unref(res);
  /* NOTE: we only store the results into the message if the entire evaluation was successful */
fail:
  filterx_scope_set_dirty(context->scope);
  return result;
}

void
filterx_eval_init_context(FilterXEvalContext *context, FilterXEvalContext *previous_context)
{
  FilterXScope *scope;

  if (previous_context)
    scope = filterx_scope_ref(previous_context->scope);
  else
    scope = filterx_scope_new();
  filterx_scope_make_writable(&scope);

  memset(context, 0, sizeof(*context));
  context->template_eval_options = DEFAULT_TEMPLATE_EVAL_OPTIONS;
  context->scope = scope;

  if (previous_context)
    context->weak_refs = previous_context->weak_refs;
  else
    context->weak_refs = g_ptr_array_new_with_free_func((GDestroyNotify) filterx_object_unref);
  context->previous_context = previous_context;

  context->eval_control_modifier = FXC_NOTSET;
  filterx_eval_set_context(context);
}

void
filterx_eval_deinit_context(FilterXEvalContext *context)
{
  if (!context->previous_context)
    g_ptr_array_free(context->weak_refs, TRUE);
  filterx_scope_unref(context->scope);
  filterx_eval_set_context(context->previous_context);
}

EVTTAG *
filterx_format_eval_result(FilterXEvalResult result)
{
  const gchar *eval_result = NULL;
  switch (result)
    {
    case FXE_SUCCESS:
      eval_result = "matched";
      break;
    case FXE_DROP:
      eval_result = "explicitly dropped";
      break;
    case FXE_FAILURE:
      eval_result = "unmatched";
      break;
    default:
      g_assert_not_reached();
      break;
    }
  return evt_tag_str("result", eval_result);
}