check_deref_check.c

/*
 * Copyright (C) 2009 Dan Carpenter.
 *
 * 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, see http://www.gnu.org/copyleft/gpl.txt
 */

#include "smatch.h"
#include "smatch_slist.h"
#include "smatch_extra.h"

static int my_id;

STATE(derefed);

static void deref_hook(struct expression *expr)
{
	if (implied_not_equal(expr, 0))
		return;
	if (is_impossible_path())
		return;
	set_state_expr(my_id, expr, &derefed);
}

static void match_condition(struct expression *expr)
{
	struct sm_state *sm;
	char *name;

	if (__in_pre_condition)
		return;

	name = get_macro_name(expr->pos);
	if (name &&
	    (strcmp(name, "likely") != 0 && strcmp(name, "unlikely") != 0))
		return;

	if (!is_pointer(expr))
		return;

	sm = get_sm_state_expr(my_id, expr);
	if (!sm || sm->state != &derefed)
		return;

	sm_warning("variable dereferenced before check '%s' (see line %d)", sm->name, sm->line);
	set_state_expr(my_id, expr, &undefined);
}

static void match_err_check(struct expression *expr, const char *name, struct symbol *sym, void *data)
{
	struct sm_state *sm;
	char *macro;

	if (__in_pre_condition)
		return;

	sm = get_sm_state(my_id, name, sym);
	if (!sm || sm->state != &derefed)
		return;

	macro = get_macro_name(expr->pos);
	if (macro && strcmp(macro, "gvt_vgpu_err") == 0)
		return;

	sm_warning("variable dereferenced before IS_ERR check '%s' (see line %d)", sm->name, sm->line);
	set_state_expr(my_id, expr, &undefined);
}

void check_deref_check(int id)
{
	my_id = id;

	add_dereference_hook(deref_hook);
	add_modification_hook(my_id, &set_undefined);

	add_hook(&match_condition, CONDITION_HOOK);

	add_function_param_key_hook("IS_ERR", &match_err_check, 0, "$", NULL);
	add_function_param_key_hook("PTR_ERR_OR_ZERO", &match_err_check, 0, "$", NULL);
	add_function_param_key_hook("IS_ERR_OR_NULL", &match_err_check, 0, "$", NULL);
}