check_return_cast.c

   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  * Complains about places that return -1 instead of -ENOMEM
  20  */
  21
  22 #include "smatch.h"
  23
  24 static int my_id;
  25
  26 static void match_return(struct expression *ret_value)
  27 {
  28         struct symbol *func_type = get_real_base_type(cur_func_sym);
  29         sval_t sval;
  30
  31         if (!func_type)
  32                 return;
  33         if (!type_unsigned(func_type))
  34                 return;
  35         if (type_bits(func_type) > 16)
  36                 return;
  37         if (!get_fuzzy_min(ret_value, &sval))
  38                 return;
  39         if (sval_is_positive(sval) || sval_cmp_val(sval, -1) == 0)
  40                 return;
  41
  42         sm_msg("warn: signedness bug returning '%s'", sval_to_str(sval));
  43 }
  44
  45 void check_return_cast(int id)
  46 {
  47         my_id = id;
  48         add_hook(&match_return, RETURN_HOOK);
  49 }