check_return_negative_var.c

   1 /*
   2  * Copyright (C) 2011 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_slist.h"
  20
  21 static int my_id;
  22
  23 static void match_return(struct expression *ret_value)
  24 {
  25         struct expression *expr;
  26         char *macro;
  27
  28         if (!ret_value)
  29                 return;
  30         expr = ret_value;
  31         if (ret_value->type != EXPR_PREOP || ret_value->op != '-')
  32                 return;
  33
  34         macro = get_macro_name(expr->unop->pos);
  35         if (macro && !strcmp(macro, "PTR_ERR")) {
  36                 sm_msg("warn: returning -%s()", macro);
  37                 return;
  38         }
  39
  40         if (!option_spammy)
  41                 return;
  42
  43         expr = get_assigned_expr(ret_value->unop);
  44         if (!expr)
  45                 return;
  46         if (expr->type != EXPR_CALL)
  47                 return;
  48
  49         sm_msg("warn: should this return really be negated?");
  50 }
  51
  52 void check_return_negative_var(int id)
  53 {
  54         if (option_project != PROJ_KERNEL)
  55                 return;
  56
  57         my_id = id;
  58         add_hook(&match_return, RETURN_HOOK);
  59 }