check_allocating_enough_data.c

   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 void db_returns_buf_size(struct expression *expr, int param, char *unused, char *math)
  21 {
  22         struct expression *call;
  23         struct symbol *left_type, *right_type;
  24         int bytes;
  25         sval_t sval;
  26         char *str;
  27
  28         if (expr->type != EXPR_ASSIGNMENT || is_fake_var_assign(expr))
  29                 return;
  30         if (!is_fresh_alloc(expr->right))
  31                 return;
  32
  33         right_type = get_pointer_type(expr->right);
  34         if (!right_type || type_bits(right_type) != -1)
  35                 return;
  36
  37         call = strip_expr(expr->right);
  38         left_type = get_pointer_type(expr->left);
  39
  40         if (!parse_call_math(call, math, &sval) || sval.value == 0)
  41                 return;
  42         if (!left_type)
  43                 return;
  44         bytes = type_bytes(left_type);
  45         if (bytes <= 0)
  46                 return;
  47         if (sval.uvalue >= bytes)
  48                 return;
  49
  50         str = expr_to_str(expr->left);
  51         sm_error("not allocating enough for = '%s' %d vs %s", str, bytes, sval_to_str(sval));
  52         free_string(str);
  53 }
  54
  55 void check_allocating_enough_data(int id)
  56 {
  57         select_return_states_hook(BUF_SIZE, &db_returns_buf_size);
  58 }