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 #include "smatch.h" 19 #include "smatch_extra.h" 20 21 static int my_id; 22 23 STATE(derefed); 24 25 static void underef(struct sm_state *sm, struct expression *mod_expr) 26 { 27 set_state(my_id, sm->name, sm->sym, &undefined); 28 } 29 30 static void match_dereference(struct expression *expr) 31 { 32 if (__in_fake_assign) 33 return; 34 35 if (expr->type != EXPR_PREOP) 36 return; 37 expr = strip_expr(expr->unop); 38 if (!is_pointer(expr)) 39 return; 40 if (implied_not_equal(expr, 0)) 41 return; 42 43 if (is_impossible_path()) 44 return; 45 46 set_state_expr(my_id, expr, &derefed); 47 } 48 49 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused) 50 { 51 struct symbol *sym; 52 char *name; 53 54 name = get_variable_from_key(arg, key, &sym); 55 if (!name || !sym) 56 goto free; 57 58 if (implied_not_equal_name_sym(name, sym, 0)) 59 goto free; 60 set_state(my_id, name, sym, &derefed); 61 62 free: 63 free_string(name); 64 } 65 66 static void match_condition(struct expression *expr) 67 { 68 struct sm_state *sm; 69 char *name; 70 71 if (__in_pre_condition) 72 return; 73 74 name = get_macro_name(expr->pos); 75 if (name && 76 (strcmp(name, "likely") != 0 && strcmp(name, "unlikely") != 0)) 77 return; 78 79 if (!is_pointer(expr)) 80 return; 81 82 sm = get_sm_state_expr(my_id, expr); 83 if (!sm || sm->state != &derefed) 84 return; 85 86 sm_warning("variable dereferenced before check '%s' (see line %d)", sm->name, sm->line); 87 set_state_expr(my_id, expr, &undefined); 88 } 89 90 void check_deref_check(int id) 91 { 92 my_id = id; 93 add_hook(&match_dereference, DEREF_HOOK); 94 add_hook(&match_condition, CONDITION_HOOK); 95 select_return_implies_hook(DEREFERENCE, &set_param_dereferenced); 96 add_modification_hook(my_id, &underef); 97 } 98