1 /*
2 * Copyright (C) 2012 Oracle.
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 an --info recipe. The goal is to print a message for every parameter
20 * which we can not avoid dereferencing. This is maybe a bit restrictive but it
21 * avoids some false positives.
22 */
23
24 #include "smatch.h"
25 #include "smatch_extra.h"
26 #include "smatch_slist.h"
27
28 static int my_id;
29
30 STATE(derefed);
31 STATE(ignore);
32 STATE(param);
33
set_ignore(struct sm_state * sm,struct expression * mod_expr)34 static void set_ignore(struct sm_state *sm, struct expression *mod_expr)
35 {
36 if (sm->state == &derefed)
37 return;
38 set_state(my_id, sm->name, sm->sym, &ignore);
39 }
40
match_function_def(struct symbol * sym)41 static void match_function_def(struct symbol *sym)
42 {
43 struct symbol *arg;
44 int i;
45
46 i = -1;
47 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
48 i++;
49 if (!arg->ident)
50 continue;
51 set_state(my_id, arg->ident->name, arg, ¶m);
52 } END_FOR_EACH_PTR(arg);
53 }
54
check_deref(struct expression * expr)55 static void check_deref(struct expression *expr)
56 {
57 struct expression *tmp;
58 struct sm_state *sm;
59
60 tmp = get_assigned_expr(expr);
61 if (tmp)
62 expr = tmp;
63 expr = strip_expr(expr);
64
65 if (get_param_num(expr) < 0)
66 return;
67
68 if (param_was_set(expr))
69 return;
70
71 sm = get_sm_state_expr(my_id, expr);
72 if (sm && slist_has_state(sm->possible, &ignore))
73 return;
74 set_state_expr(my_id, expr, &derefed);
75 }
76
match_dereference(struct expression * expr)77 static void match_dereference(struct expression *expr)
78 {
79 if (expr->type != EXPR_PREOP)
80 return;
81 check_deref(expr->unop);
82 }
83
set_param_dereferenced(struct expression * call,struct expression * arg,char * key,char * unused)84 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
85 {
86 /* XXX FIXME: param_implies has more information now */
87 if (strcmp(key, "$") != 0)
88 return;
89 check_deref(arg);
90 }
91
process_states(void)92 static void process_states(void)
93 {
94 struct sm_state *tmp;
95 int arg;
96 const char *name;
97
98 FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) {
99 if (tmp->state != &derefed)
100 continue;
101 arg = get_param_num_from_sym(tmp->sym);
102 if (arg < 0)
103 continue;
104 name = get_param_name(tmp);
105 if (!name)
106 continue;
107 sql_insert_return_implies(DEREFERENCE, arg, name, "1");
108 } END_FOR_EACH_SM(tmp);
109 }
110
match_pointer_as_array(struct expression * expr)111 static void match_pointer_as_array(struct expression *expr)
112 {
113 if (!is_array(expr))
114 return;
115 check_deref(get_array_base(expr));
116 }
117
check_dereferences_param(int id)118 void check_dereferences_param(int id)
119 {
120 my_id = id;
121
122 add_hook(&match_function_def, FUNC_DEF_HOOK);
123
124 add_hook(&match_dereference, DEREF_HOOK);
125 add_hook(&match_pointer_as_array, OP_HOOK);
126 select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
127 add_modification_hook(my_id, &set_ignore);
128
129 all_return_states_hook(&process_states);
130 }
131