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 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 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 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 77 static void match_dereference(struct expression *expr) 78 { 79 if (expr->type != EXPR_PREOP) 80 return; 81 if (getting_address()) 82 return; 83 check_deref(expr->unop); 84 } 85 86 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused) 87 { 88 /* XXX FIXME: param_implies has more information now */ 89 if (strcmp(key, "$") != 0) 90 return; 91 check_deref(arg); 92 } 93 94 static void process_states(void) 95 { 96 struct sm_state *tmp; 97 int arg; 98 const char *name; 99 100 FOR_EACH_MY_SM(my_id, __get_cur_stree(), tmp) { 101 if (tmp->state != &derefed) 102 continue; 103 arg = get_param_num_from_sym(tmp->sym); 104 if (arg < 0) 105 continue; 106 name = get_param_name(tmp); 107 if (!name) 108 continue; 109 sql_insert_return_implies(DEREFERENCE, arg, name, "1"); 110 } END_FOR_EACH_SM(tmp); 111 } 112 113 static void match_pointer_as_array(struct expression *expr) 114 { 115 if (!is_array(expr)) 116 return; 117 check_deref(get_array_base(expr)); 118 } 119 120 void check_dereferences_param(int id) 121 { 122 my_id = id; 123 124 add_hook(&match_function_def, FUNC_DEF_HOOK); 125 126 add_hook(&match_dereference, DEREF_HOOK); 127 add_hook(&match_pointer_as_array, OP_HOOK); 128 select_return_implies_hook(DEREFERENCE, &set_param_dereferenced); 129 add_modification_hook(my_id, &set_ignore); 130 131 all_return_states_hook(&process_states); 132 } 133