extra: add more parameter dereferences
[smatch.git] / smatch_untracked_param.c
blob1da5d75ee35f57d2cbbfa85037238fdd60321b96
1 /*
2 * Copyright (C) 2014 Oracle.
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.
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.
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
19 * Sometimes we aren't able to track a variable through a function call. This
20 * usually happens because a function changes too many variables so we give up.
21 * Another reason this happens is because we call a function pointer and there
22 * are too many functions which implement that function pointer so we give up.
23 * Also maybe we don't have the database enabled.
25 * The goal here is to make a call back so what if we call:
27 * frob(&foo);
29 * but we're not able to say what happens to "foo", then let's assume that we
30 * don't know anything about "foo" if it's an untracked call.
34 #include "smatch.h"
35 #include "smatch_slist.h"
36 #include "smatch_extra.h"
38 static int my_id;
39 static int tracked;
41 STATE(untracked);
43 typedef void (untracked_hook)(struct expression *call, int param);
44 DECLARE_PTR_LIST(untracked_hook_list, untracked_hook *);
45 static struct untracked_hook_list *untracked_hooks;
47 struct int_stack *tracked_stack;
49 void add_untracked_param_hook(void (func)(struct expression *call, int param))
51 untracked_hook **p = malloc(sizeof(untracked_hook *));
52 *p = func;
53 add_ptr_list(&untracked_hooks, p);
56 static void call_untracked_callbacks(struct expression *expr, int param)
58 untracked_hook **fn;
60 FOR_EACH_PTR(untracked_hooks, fn) {
61 (*fn)(expr, param);
62 } END_FOR_EACH_PTR(fn);
65 static void assume_tracked(struct expression *call_expr, int param, char *key, char *value)
67 tracked = 1;
70 static void mark_untracked(struct expression *expr, int param, char *key, char *value)
72 char *name;
73 struct symbol *sym;
75 while (expr->type == EXPR_ASSIGNMENT)
76 expr = strip_expr(expr->right);
77 if (expr->type != EXPR_CALL)
78 return;
80 name = return_state_to_var_sym(expr, param, key, &sym);
81 if (!name || !sym)
82 goto free;
84 call_untracked_callbacks(expr, param);
85 set_state(my_id, name, sym, &untracked);
86 free:
87 free_string(name);
90 static int lost_in_va_args(struct expression *expr)
92 struct symbol *fn;
93 char *name;
94 int is_lost;
96 fn = get_type(expr->fn);
97 if (!fn || !fn->variadic)
98 return 0;
100 is_lost = 1;
101 name = expr_to_var(expr->fn);
102 if (strstr(name, "print"))
103 is_lost = 0;
104 free_string(name);
106 return is_lost;
109 static void match_after_call(struct expression *expr)
111 struct expression *arg;
112 struct symbol *type;
113 int i;
115 if (lost_in_va_args(expr))
116 tracked = 0;
118 if (tracked) {
119 tracked = 0;
120 return;
123 i = -1;
124 FOR_EACH_PTR(expr->args, arg) {
125 i++;
127 type = get_type(arg);
128 if (!type || type->type != SYM_PTR)
129 continue;
131 call_untracked_callbacks(expr, i);
132 set_state_expr(my_id, arg, &untracked);
133 } END_FOR_EACH_PTR(arg);
136 static void print_untracked_params(int return_id, char *return_ranges, struct expression *expr)
138 struct symbol *arg;
139 int param;
141 param = -1;
142 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, arg) {
143 param++;
145 if (!arg->ident)
146 continue;
147 if (!get_state(my_id, arg->ident->name, arg))
148 continue;
150 sql_insert_return_states(return_id, return_ranges,
151 UNTRACKED_PARAM, param, "$", "");
152 } END_FOR_EACH_PTR(arg);
155 static void match_param_assign(struct expression *expr)
157 struct expression *right;
158 struct symbol *type;
159 int param;
161 if (__in_fake_assign)
162 return;
164 right = strip_expr(expr->right);
165 type = get_type(right);
166 if (!type || type->type != SYM_PTR)
167 return;
169 param = get_param_num(right);
170 if (param < 0)
171 return;
173 set_state_expr(my_id, right, &untracked);
177 static void match_param_assign_in_asm(struct statement *stmt)
180 struct expression *expr;
181 struct symbol *type;
182 int state = 0;
183 int param;
185 FOR_EACH_PTR(stmt->asm_inputs, expr) {
186 switch (state) {
187 case 0: /* identifier */
188 case 1: /* constraint */
189 state++;
190 continue;
191 case 2: /* expression */
192 state = 0;
194 expr = strip_expr(expr);
195 type = get_type(expr);
196 if (!type || type->type != SYM_PTR)
197 continue;
198 param = get_param_num(expr);
199 if (param < 0)
200 continue;
201 set_state_expr(my_id, expr, &untracked);
202 continue;
204 } END_FOR_EACH_PTR(expr);
207 static void match_inline_start(struct expression *expr)
209 push_int(&tracked_stack, tracked);
212 static void match_inline_end(struct expression *expr)
214 tracked = pop_int(&tracked_stack);
217 void register_untracked_param(int id)
219 my_id = id;
221 select_return_states_hook(INTERNAL, &assume_tracked);
222 select_return_states_hook(UNTRACKED_PARAM, &mark_untracked);
223 add_hook(&match_after_call, FUNCTION_CALL_HOOK_AFTER_DB);
225 add_split_return_callback(&print_untracked_params);
227 add_hook(&match_param_assign, ASSIGNMENT_HOOK);
228 add_hook(&match_param_assign_in_asm, ASM_HOOK);
230 add_hook(&match_inline_start, INLINE_FN_START);
231 add_hook(&match_inline_end, INLINE_FN_END);