check_err_ptr.c

   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_slist.h"
  20
  21 static int my_id;
  22
  23 static int err_ptr = 0;
  24 static int returns_null = 0;
  25
  26 static void match_err_ptr(struct expression *expr)
  27 {
  28         expr = strip_expr(expr);
  29         if (!expr)
  30                 return;
  31         if (expr->type != EXPR_CALL)
  32                 return;
  33
  34         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
  35                 return;
  36         if (!strcmp(expr->fn->symbol->ident->name, "ERR_PTR"))
  37                 err_ptr = 1;
  38 }
  39
  40 extern int check_assigned_expr_id;
  41 static void match_return(struct expression *ret_value)
  42 {
  43         struct state_list *slist;
  44         struct sm_state *tmp;
  45         sval_t sval;
  46
  47         if (__inline_fn)
  48                 return;
  49         match_err_ptr(ret_value);
  50         slist = get_possible_states_expr(check_assigned_expr_id, ret_value);
  51         FOR_EACH_PTR(slist, tmp) {
  52                 if (tmp->state == &undefined || tmp->state == &merged)
  53                         continue;
  54                 match_err_ptr((struct expression *)tmp->state->data);
  55         } END_FOR_EACH_PTR(tmp);
  56
  57         if (get_implied_value(ret_value, &sval)) {
  58                 if (sval.value == 0)
  59                         returns_null = 1;
  60         }
  61 }
  62
  63 static void match_end_func(struct symbol *sym)
  64 {
  65         if (__inline_fn)
  66                 return;
  67         if (err_ptr)
  68                 sm_info("returns_err_ptr");
  69         err_ptr = 0;
  70         returns_null = 0;
  71 }
  72
  73 void check_err_ptr(int id)
  74 {
  75         if (option_project != PROJ_KERNEL)
  76                 return;
  77         if (!option_info)
  78                 return;
  79
  80         my_id = id;
  81         add_hook(&match_return, RETURN_HOOK);
  82         add_hook(&match_end_func, END_FUNC_HOOK);
  83 }