check_freeing_devm.c

   1 /*
   2  * Copyright (C) 2013 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 #include "smatch.h"
  19
  20 STATE(devm);
  21
  22 static int my_id;
  23
  24 static void match_assign(const char *fn, struct expression *expr, void *unused)
  25 {
  26         set_state_expr(my_id, expr->left, &devm);
  27 }
  28
  29 /*
  30  * This hook deals with things like:
  31  * ptr = devm_kmalloc(...);
  32  * if (!ptr)
  33  *      return -ENOMEM;
  34  * another_val = ptr;                   <==
  35  */
  36 static void match_reassign(struct expression *expr)
  37 {
  38         struct expression *left, *right;
  39
  40         if (expr->op != '=')
  41                 return;
  42
  43         right = strip_expr(expr->right);
  44         if (!get_state_expr(my_id, right))
  45                 return;
  46
  47         left = strip_expr(expr->left);
  48
  49         set_state_expr(my_id, left, &devm);
  50 }
  51
  52 static void match_free_func(const char *fn, struct expression *expr, void *_arg)
  53 {
  54         struct expression *arg_expr;
  55         int arg = PTR_INT(_arg);
  56         char *name;
  57
  58         arg_expr = get_argument_from_call_expr(expr->args, arg);
  59         if (!get_state_expr(my_id, arg_expr))
  60                 return;
  61         name = expr_to_str(arg_expr);
  62         sm_warning("passing devm_ allocated variable to %s. '%s'", fn, name);
  63         free_string(name);
  64 }
  65
  66 static void register_funcs_from_file(void)
  67 {
  68         struct token *token;
  69         const char *func;
  70         int arg;
  71
  72         token = get_tokens_file("kernel.frees_argument");
  73         if (!token)
  74                 return;
  75         if (token_type(token) != TOKEN_STREAMBEGIN)
  76                 return;
  77         token = token->next;
  78         while (token_type(token) != TOKEN_STREAMEND) {
  79                 if (token_type(token) != TOKEN_IDENT)
  80                         return;
  81                 func = show_ident(token->ident);
  82                 token = token->next;
  83                 if (token_type(token) != TOKEN_NUMBER)
  84                         return;
  85                 arg = atoi(token->number);
  86                 add_function_hook(func, &match_free_func, INT_PTR(arg));
  87                 token = token->next;
  88         }
  89         clear_token_alloc();
  90 }
  91
  92 void check_freeing_devm(int id)
  93 {
  94         if (option_project != PROJ_KERNEL)
  95                 return;
  96
  97         my_id = id;
  98
  99         add_function_assign_hook("devm_kmalloc", &match_assign, NULL);
 100         add_function_assign_hook("devm_kzalloc", &match_assign, NULL);
 101         add_function_assign_hook("devm_kcalloc", &match_assign, NULL);
 102         add_function_assign_hook("devm_kmalloc_array", &match_assign, NULL);
 103
 104         add_function_assign_hook("devm_kmemdup", &match_assign, NULL);
 105         add_function_assign_hook("devm_kstrdup", &match_assign, NULL);
 106         add_function_assign_hook("devm_kasprintf", &match_assign, NULL);
 107         add_function_assign_hook("devm_kvasprintf", &match_assign, NULL);
 108
 109         add_function_hook("kfree", &match_free_func, INT_PTR(0));
 110         add_function_hook("krealloc", &match_free_func, INT_PTR(0));
 111         register_funcs_from_file();
 112
 113         add_hook(&match_reassign, ASSIGNMENT_HOOK);
 114 }