1 /*
2 * Copyright (C) 2014 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 file is sort of like check_dereferences_param.c. In theory the one
20 * difference should be that the param is NULL it should still be counted as a
21 * free. But for now I don't handle that case.
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(freed);
31 STATE(ignore);
32
set_ignore(struct sm_state * sm,struct expression * mod_expr)33 static void set_ignore(struct sm_state *sm, struct expression *mod_expr)
34 {
35 set_state(my_id, sm->name, sm->sym, &ignore);
36 }
37
freed_variable(struct expression * expr)38 static void freed_variable(struct expression *expr)
39 {
40 struct sm_state *sm;
41
42 expr = strip_expr(expr);
43 if (get_param_num(expr) < 0)
44 return;
45
46 sm = get_sm_state_expr(my_id, expr);
47 if (sm && slist_has_state(sm->possible, &ignore))
48 return;
49 set_state_expr(my_id, expr, &freed);
50 }
51
match_free(const char * fn,struct expression * expr,void * param)52 static void match_free(const char *fn, struct expression *expr, void *param)
53 {
54 struct expression *arg;
55
56 arg = get_argument_from_call_expr(expr->args, PTR_INT(param));
57 if (!arg)
58 return;
59 freed_variable(arg);
60 }
61
set_param_freed(struct expression * call,struct expression * arg,char * key,char * unused)62 static void set_param_freed(struct expression *call, struct expression *arg, char *key, char *unused)
63 {
64 /* XXX FIXME: return_implies has been updated with more information */
65 if (strcmp(key, "$") != 0)
66 return;
67 freed_variable(arg);
68 }
69
process_states(void)70 static void process_states(void)
71 {
72 struct sm_state *sm;
73 int param;
74 const char *param_name;
75
76 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
77 if (sm->state != &freed)
78 continue;
79 param = get_param_num_from_sym(sm->sym);
80 if (param < 0)
81 continue;
82 param_name = get_param_name(sm);
83 if (!param_name)
84 continue;
85 sql_insert_return_implies(PARAM_FREED, param, param_name, "1");
86 } END_FOR_EACH_SM(sm);
87
88 }
89
check_frees_param(int id)90 void check_frees_param(int id)
91 {
92 my_id = id;
93
94 if (option_project == PROJ_KERNEL) {
95 /* The kernel uses check_frees_param_strict.c */
96 return;
97 }
98
99 add_function_hook("free", &match_free, INT_PTR(0));
100
101 select_return_implies_hook(PARAM_FREED, &set_param_freed);
102 add_modification_hook(my_id, &set_ignore);
103
104 all_return_states_hook(&process_states);
105 }
106