/*
 * Copyright 2024 Linaro Ltd.
 *
 * 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"

static int my_id;

STATE(locked);

static char *get_lock_member(struct expression *expr)
{
	if (!expr)
		return NULL;

	if (expr->type != EXPR_PREOP || expr->op != '&')
		return NULL;
	expr = expr->unop;
	return get_member_name(expr);
}

static void match_lock(struct lock_info *info, struct expression *expr, const char *name)
{
	char *member;

	member = get_lock_member(expr);
	if (local_debug)
		sm_msg("%s: expr='%s' member='%s' name='%s'", __func__, expr_to_str(expr), member, name);
	if (!member)
		return;
	set_state(my_id, member, NULL, &locked);
}

static void match_unlock(struct lock_info *info, struct expression *expr, const char *name)
{
	char *member;

	member = get_lock_member(expr);
	if (!member)
		return;
	if (!get_state(my_id, member, NULL))
		return;
	set_state(my_id, member, NULL, &undefined);
}

static void insert_caller_locked(struct expression *expr)
{
	struct sm_state *sm;

	if (!has_states(__get_cur_stree(), my_id))
		return;

	FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
		if (sm->state != &locked)
			continue;
		sql_insert_caller_info(expr, TYPE_LOCKED, -2, sm->name, "");
	} END_FOR_EACH_SM(sm);
}

void select_caller_locked(const char *name, struct symbol *sym, char *key, char *value)
{
	set_state(my_id, key, NULL, &locked);
}

static void match_assert_held(struct expression *expr)
{
	struct smatch_state *state;
	char *member;

	/* lock_is_held() is called like this "lock_is_held(&(lock)->dep_map)",
	 * and we want to look at just "lock".
	 */
	if (expr->type != EXPR_PREOP || expr->op != '&')
		return;
	expr = expr->unop;
	if (expr->type != EXPR_DEREF)
		return;
	expr = strip_expr(expr->deref);

	member = get_member_name(expr);
	if (!member)
		return;

	state = get_state(my_id, member, NULL);
	if (state == &locked)
		return;

	sm_warning("lock '%s' might not be held", member);
}

void check_lock_held_type(int id)
{
	my_id = id;

	add_lock_hook(&match_lock);
	add_unlock_hook(&match_unlock);
	select_caller_info_hook(select_caller_locked, TYPE_LOCKED);
	add_hook(&insert_caller_locked, FUNCTION_CALL_HOOK);

	add_param_key_expr_hook("lock_is_held", &match_assert_held, 0, "$", NULL);
}