1 /*
2 * Copyright (C) 2017 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 * Say you have assign a function to a function pointer and you assign a
20 * pointer to the data argument then we want to record some information about
21 * the argument. Right now what I mainly want to record is the type of it, I
22 * guess.
23 *
24 */
25
26 #include "smatch.h"
27 #include "smatch_extra.h"
28 #include "smatch_slist.h"
29 #include <ctype.h>
30
31 static int my_id;
32
assigns_parameters(struct expression * fn,struct expression * arg)33 static int assigns_parameters(struct expression *fn, struct expression *arg)
34 {
35 int fn_param, arg_param;
36 char buf[32];
37
38 fn_param = get_param_num(fn);
39 if (fn_param < 0)
40 return 0;
41
42 arg_param = get_param_num(arg);
43 if (arg_param < 0)
44 return 0;
45
46 snprintf(buf, sizeof(buf), "%d", arg_param);
47 sql_insert_return_implies(FN_ARG_LINK, fn_param, "$", buf);
48 return 1;
49 }
50
link_function_arg(struct expression * fn,int param,struct expression * arg)51 static void link_function_arg(struct expression *fn, int param, struct expression *arg)
52 {
53 struct symbol *type;
54
55 if (!fn || !arg)
56 return;
57 if (assigns_parameters(fn, arg))
58 return;
59
60 type = get_type(arg);
61 if (!type || type->type != SYM_PTR)
62 return;
63 type = get_real_base_type(type);
64 if (!type)
65 return;
66 // FIXME: param shouldn't always be 0?
67 sql_insert_fn_data_link(fn, PASSES_TYPE, param, "$", type_to_str(type));
68 }
69
70 char *next_param_name;
71 struct symbol *next_param_sym;
72 struct expression *next_fn;
match_assign_param(struct expression * expr)73 static void match_assign_param(struct expression *expr)
74 {
75 struct symbol *sym;
76 char *name;
77
78 if (!next_param_name)
79 return;
80
81 name = expr_to_var_sym(expr->left, &sym);
82 if (!name || !sym) {
83 free_string(name);
84 return;
85 }
86
87 if (sym != next_param_sym ||
88 strcmp(name, next_param_name) != 0)
89 return;
90
91 link_function_arg(next_fn, 0, strip_expr(expr->right));
92
93 next_param_name = 0;
94 next_param_sym = NULL;
95 next_fn = NULL;
96 }
97
get_arg_ptr(void * _arg_ptr,int argc,char ** argv,char ** azColName)98 static int get_arg_ptr(void *_arg_ptr, int argc, char **argv, char **azColName)
99 {
100 char **arg_ptr = _arg_ptr;
101
102 *arg_ptr = NULL;
103 if (argc != 1)
104 return 0;
105 *arg_ptr = alloc_string(argv[0]);
106 return 0;
107 }
108
get_data_member(char * fn_member,struct expression * expr,struct symbol ** sym)109 static char *get_data_member(char *fn_member, struct expression *expr, struct symbol **sym)
110 {
111 struct symbol *tmp_sym;
112 char *fn_str;
113 char *arg_ptr = NULL;
114 char *end_type;
115 int len_ptr, len_str;
116 char buf[128];
117
118 *sym = NULL;
119 run_sql(get_arg_ptr, &arg_ptr,
120 "select data from fn_ptr_data_link where fn_ptr = '%s';", fn_member);
121 if (!arg_ptr)
122 return NULL;
123 end_type = strchr(arg_ptr, '>');
124 if (!end_type)
125 return NULL;
126 end_type++;
127 fn_str = expr_to_var_sym(expr, &tmp_sym);
128 if (!fn_str || !tmp_sym)
129 return NULL;
130 len_ptr = strlen(fn_member);
131 len_str = strlen(fn_str);
132 while (len_str > 0 && len_ptr > 0) {
133 if (fn_str[len_str - 1] != fn_member[len_ptr - 1])
134 break;
135 if (fn_str[len_str - 1] == '>')
136 break;
137 len_str--;
138 len_ptr--;
139 }
140
141 strncpy(buf, fn_str, sizeof(buf));
142 snprintf(buf + len_str, sizeof(buf) - len_str, "%s", end_type);
143 *sym = tmp_sym;
144 return alloc_string(buf);
145 }
146
match_assign_function(struct expression * expr)147 static void match_assign_function(struct expression *expr)
148 {
149 struct expression *right, *arg;
150 struct symbol *sym;
151 char *data_member;
152 struct symbol *type;
153 char *member_name;
154
155 right = strip_expr(expr->right);
156 if (right->type == EXPR_PREOP && right->op == '&')
157 right = strip_expr(right->unop);
158
159 type = get_type(right);
160 if (type && type->type == SYM_PTR)
161 type = get_real_base_type(type);
162 if (!type || type->type != SYM_FN)
163 return;
164
165 member_name = get_member_name(expr->left);
166 if (!member_name)
167 return;
168
169 data_member = get_data_member(member_name, expr->left, &sym);
170 if (!data_member || !sym) {
171 free_string(data_member);
172 data_member = NULL;
173 }
174
175 arg = get_assigned_expr_name_sym(data_member, sym);
176 if (arg) {
177 link_function_arg(right, 0, arg);
178 } else {
179 next_param_name = data_member;
180 next_param_sym = sym;
181 next_fn = right;
182 }
183 }
184
is_recursive_call(struct expression * call)185 static int is_recursive_call(struct expression *call)
186 {
187 if (call->fn->type != EXPR_SYMBOL)
188 return 0;
189 if (call->fn->symbol == cur_func_sym)
190 return 1;
191 return 0;
192 }
193
check_passes_fn_and_data(struct expression * call,struct expression * fn,char * key,char * value)194 static void check_passes_fn_and_data(struct expression *call, struct expression *fn, char *key, char *value)
195 {
196 struct expression *arg;
197 struct symbol *type;
198 int data_nr;
199
200 if (is_recursive_call(call))
201 return;
202
203 type = get_type(fn);
204 if (!type || type->type != SYM_FN)
205 return;
206
207 if (!isdigit(value[0]))
208 return;
209 data_nr = atoi(value);
210 arg = get_argument_from_call_expr(call->args, data_nr);
211 if (!arg)
212 return;
213 link_function_arg(fn, 0, arg);
214 }
215
match_end_func(struct symbol * sym)216 static void match_end_func(struct symbol *sym)
217 {
218 next_param_sym = NULL;
219 next_fn = NULL;
220 }
221
register_about_fn_ptr_arg(int id)222 void register_about_fn_ptr_arg(int id)
223 {
224 my_id = id;
225
226 if (0 && !option_info)
227 return;
228 add_hook(match_assign_param, ASSIGNMENT_HOOK);
229 add_hook(match_assign_function, ASSIGNMENT_HOOK);
230 select_return_implies_hook(FN_ARG_LINK, &check_passes_fn_and_data);
231 add_hook(&match_end_func, END_FUNC_HOOK);
232 }
233