check_allocation_funcs.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 <fcntl.h>
  19 #include <unistd.h>
  20 #include "parse.h"
  21 #include "smatch.h"
  22 #include "smatch_slist.h"
  23
  24 static int my_id;
  25
  26 /*
  27  * Print a list of functions that return newly allocated memory.
  28  */
  29
  30 static struct tracker_list *allocated;
  31
  32 static const char *allocation_funcs[] = {
  33         "kmalloc",
  34         "kzalloc",
  35         "kcalloc",
  36         "__alloc_skb",
  37         NULL,
  38 };
  39
  40 static void match_allocation(const char *fn, struct expression *expr,
  41                              void *info)
  42 {
  43         char *left_name;
  44         struct symbol *left_sym;
  45
  46         left_name = expr_to_var_sym(expr->left, &left_sym);
  47         if (!left_name || !left_sym)
  48                 goto free;
  49         if (left_sym->ctype.modifiers &
  50             (MOD_NONLOCAL | MOD_STATIC | MOD_ADDRESSABLE))
  51                 goto free;
  52         add_tracker(&allocated, my_id, left_name, left_sym);
  53 free:
  54         free_string(left_name);
  55 }
  56
  57 static int returns_new_stuff = 0;
  58 static int returns_old_stuff = 0;
  59 static void match_return(struct expression *ret_value)
  60 {
  61         char *name;
  62         struct symbol *sym;
  63         sval_t tmp;
  64
  65         if (__inline_fn)
  66                 return;
  67         if (get_value(ret_value, &tmp) && tmp.value == 0)
  68                 return;
  69         returns_new_stuff = 1;
  70         name = expr_to_var_sym(ret_value, &sym);
  71         if (!name || !sym) {
  72                 returns_old_stuff = 1;
  73                 goto free;
  74         }
  75         if (!in_tracker_list(allocated, my_id, name, sym))
  76                 returns_old_stuff = 1;
  77 free:
  78         free_string(name);
  79 }
  80
  81 static void match_end_func(struct symbol *sym)
  82 {
  83         if (__inline_fn)
  84                 return;
  85         if (returns_new_stuff && !returns_old_stuff)
  86                 sm_info("allocation func");
  87         free_trackers_and_list(&allocated);
  88         returns_new_stuff = 0;
  89         returns_old_stuff = 0;
  90 }
  91
  92 void check_allocation_funcs(int id)
  93 {
  94         int i;
  95
  96         if (!option_info || option_project != PROJ_KERNEL)
  97                 return;
  98
  99         my_id = id;
 100         add_hook(&match_return, RETURN_HOOK);
 101         add_hook(&match_end_func, AFTER_FUNC_HOOK);
 102         for (i = 0; allocation_funcs[i]; i++) {
 103                 add_function_assign_hook(allocation_funcs[i],
 104                                          &match_allocation, NULL);
 105         }
 106 }