/*
 * Copyright (C) 2021 Oracle.
 *
 * 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
 */

/*
 * This module answers the question:
 * is_probe_function()
 * called_from_probe() which returns 1 for yes, -1 for maybe and 0 for no.
 *
 */

#include "smatch.h"

static int my_id;

STATE(from_probe);
STATE(maybe);

static unsigned long is_probe_fn;

bool is_probe_function(void)
{
	return is_probe_fn;
}

int called_from_probe(void)
{
	struct smatch_state *state;

	if (is_probe_function())
		return 1;

	state = get_state(my_id, "from_probe", NULL);
	if (state == &from_probe)
		return 1;
	if (state == &maybe)
		return -1;

	return 0;
}

static struct smatch_state *merge_func(struct smatch_state *s1, struct smatch_state *s2)
{
	return &maybe;
}

static void match_probe_call(struct expression *expr)
{
	char *name;

	name = get_member_name(expr);
	if (!name)
		return;
	if (strstr(name, "->probe"))
		sql_insert_caller_info(expr, PROBE_FN, -1, "", "");
	free_string(name);
}

static void select_probe_fn(const char *name, struct symbol *sym, char *key, char *value)
{
	is_probe_fn = 1;
}

static void match_call_info(struct expression *expr)
{
	int call;

	call = called_from_probe();
	if (!call)
		return;

	sql_insert_caller_info(expr, CALLED_FROM_PROBE, -1, "", (call == 1) ? "y" : "m");
}

static void select_from_probe(const char *name, struct symbol *sym, char *key, char *value)
{
	if (strcmp(value, "y") == 0)
		set_state(my_id, "from_probe", NULL, &from_probe);
	else
		set_state(my_id, "from_probe", NULL, &maybe);
}

void register_kernel_probe(int id)
{
	my_id = id;

	if (option_project != PROJ_KERNEL)
		return;

	add_merge_hook(my_id, &merge_func);

	add_function_data(&is_probe_fn);
	add_hook(&match_probe_call, FUNCTION_CALL_HOOK);
	select_caller_info_hook(&select_probe_fn, PROBE_FN);

	add_hook(&match_call_info, FUNCTION_CALL_HOOK);
	select_caller_info_hook(&select_from_probe, CALLED_FROM_PROBE);
}