1/*
2 * Copyright (C) 2009 Dan Carpenter.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18/*
19 * This is not a check.  It just saves an struct expression pointer
20 * whenever something is assigned.  This can be used later on by other scripts.
21 */
22
23#include "smatch.h"
24#include "smatch_slist.h"
25#include "smatch_extra.h"
26
27int check_assigned_expr_id;
28static int my_id;
29static int link_id;
30
31static struct expression *skip_mod;
32
33static void undef(struct sm_state *sm, struct expression *mod_expr)
34{
35	if (mod_expr == skip_mod)
36		return;
37	set_state(my_id, sm->name, sm->sym, &undefined);
38}
39
40struct expression *get_assigned_expr(struct expression *expr)
41{
42	struct smatch_state *state;
43
44	state = get_state_expr(my_id, expr);
45	if (!state)
46		return NULL;
47	return (struct expression *)state->data;
48}
49
50struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
51{
52	struct smatch_state *state;
53
54	state = __get_state(my_id, name, sym);
55	if (!state)
56		return NULL;
57	return (struct expression *)state->data;
58}
59
60static void match_assignment(struct expression *expr)
61{
62	static struct expression *ignored_expr;
63	struct symbol *left_sym, *right_sym;
64	char *left_name = NULL;
65	char *right_name = NULL;
66
67	if (expr->op != '=')
68		return;
69	if (is_fake_call(expr->right))
70		return;
71	if (__in_fake_struct_assign) {
72		struct range_list *rl;
73
74		if (!get_implied_rl(expr->right, &rl))
75			return;
76		if (is_whole_rl(rl))
77			return;
78	}
79
80	if (expr->left == ignored_expr)
81		return;
82	ignored_expr = NULL;
83	if (__in_fake_parameter_assign)
84		ignored_expr = expr->left;
85
86	left_name = expr_to_var_sym(expr->left, &left_sym);
87	if (!left_name || !left_sym)
88		goto free;
89	set_state(my_id, left_name, left_sym, alloc_state_expr(strip_expr(expr->right)));
90
91	right_name = expr_to_var_sym(expr->right, &right_sym);
92	if (!right_name || !right_sym)
93		goto free;
94
95	store_link(link_id, right_name, right_sym, left_name, left_sym);
96
97free:
98	free_string(left_name);
99	free_string(right_name);
100}
101
102static void record_param_assignment(struct expression *expr, int param, char *key, char *value)
103{
104	struct expression *arg, *right;
105	struct symbol *sym;
106	char *name;
107	char *p;
108	int right_param;
109
110	while (expr->type == EXPR_ASSIGNMENT)
111		expr = strip_expr(expr->right);
112	if (!expr || expr->type != EXPR_CALL)
113		return;
114
115	p = strstr(value, "[$");
116	if (!p)
117		return;
118
119	p += 2;
120	right_param = strtol(p, &p, 10);
121	if (*p != ']')
122		return;
123
124	arg = get_argument_from_call_expr(expr->args, param);
125	right = get_argument_from_call_expr(expr->args, right_param);
126	if (!right || !arg)
127		return;
128	name = get_variable_from_key(arg, key, &sym);
129	if (!name || !sym)
130		goto free;
131
132	skip_mod = expr;
133	set_state(my_id, name, sym, alloc_state_expr(right));
134free:
135	free_string(name);
136}
137
138void register_assigned_expr(int id)
139{
140	my_id = check_assigned_expr_id = id;
141	set_dynamic_states(check_assigned_expr_id);
142	add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
143	add_modification_hook(my_id, &undef);
144	select_return_states_hook(PARAM_SET, &record_param_assignment);
145}
146
147void register_assigned_expr_links(int id)
148{
149	link_id = id;
150	set_dynamic_states(link_id);
151	db_ignore_states(link_id);
152	set_up_link_functions(my_id, link_id);
153}
154
155