xref: /illumos-gate/usr/src/tools/smatch/src/smatch_assigned_expr.c (revision c85f09cc92abd00c84e58ec9f0f5d942906cb713)
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 
27 int check_assigned_expr_id;
28 static int my_id;
29 static int link_id;
30 
31 static struct expression *skip_mod;
32 
undef(struct sm_state * sm,struct expression * mod_expr)33 static 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 
get_assigned_expr(struct expression * expr)40 struct 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 
get_assigned_expr_name_sym(const char * name,struct symbol * sym)50 struct 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 
match_assignment(struct expression * expr)60 static 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 
97 free:
98 	free_string(left_name);
99 	free_string(right_name);
100 }
101 
record_param_assignment(struct expression * expr,int param,char * key,char * value)102 static 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));
134 free:
135 	free_string(name);
136 }
137 
register_assigned_expr(int id)138 void 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 
register_assigned_expr_links(int id)147 void 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