1 /* 2 * Copyright (C) 2010 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 20 static int my_id; 21 22 static void match_free(const char *fn, struct expression *expr, void *data) 23 { 24 struct expression *arg_expr; 25 char *name; 26 sval_t sval; 27 28 arg_expr = get_argument_from_call_expr(expr->args, 0); 29 if (!get_implied_value(arg_expr, &sval)) 30 return; 31 if (sval.value != 0) 32 return; 33 name = expr_to_var(arg_expr); 34 sm_warning("calling %s() when '%s' is always NULL.", fn, name); 35 free_string(name); 36 } 37 38 void check_freeing_null(int id) 39 { 40 my_id = id; 41 if (!option_spammy) 42 return; 43 if (option_project == PROJ_KERNEL) 44 add_function_hook("kfree", &match_free, NULL); 45 else 46 add_function_hook("free", &match_free, NULL); 47 } 48