check_stack.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 /*
  19  * The kernel has a small stack so putting huge structs and arrays on the
  20  * stack is a bug.
  21  *
  22  */
  23
  24 #include "smatch.h"
  25
  26 static int my_id;
  27
  28 static int total_size;
  29 static int max_size;
  30 static int max_lineno;
  31 static int complained;
  32
  33 #define MAX_ALLOWED 1000
  34
  35 static void scope_end(void *_size)
  36 {
  37         int size = PTR_INT(_size);
  38         total_size -= size;
  39 }
  40
  41 static void match_declarations(struct symbol *sym)
  42 {
  43         struct symbol *base;
  44         const char *name;
  45
  46         base = get_base_type(sym);
  47         if (sym->ctype.modifiers & MOD_STATIC)
  48                 return;
  49         name = sym->ident->name;
  50         total_size += type_bytes(base);
  51         if (total_size > max_size) {
  52                 max_size = total_size;
  53                 max_lineno = get_lineno();
  54         }
  55         if (type_bytes(base) >= MAX_ALLOWED) {
  56                 complained = 1;
  57                 sm_warning("'%s' puts %d bytes on stack", name, type_bytes(base));
  58         }
  59         add_scope_hook(&scope_end, INT_PTR(type_bytes(base)));
  60 }
  61
  62 static void match_end_func(struct symbol *sym)
  63 {
  64         if (__inline_fn)
  65                 return;
  66
  67         if ((max_size >= MAX_ALLOWED) && !complained) {
  68                 sm_printf("%s:%d %s() ", get_filename(), max_lineno, get_function());
  69                 sm_printf("warn: function puts %d bytes on stack\n", max_size);
  70         }
  71         total_size = 0;
  72         complained = 0;
  73         max_size = 0;
  74         max_lineno = 0;
  75 }
  76
  77 void check_stack(int id)
  78 {
  79         if (option_project != PROJ_KERNEL || !option_spammy)
  80                 return;
  81
  82         my_id = id;
  83         add_hook(&match_declarations, DECLARATION_HOOK);
  84         add_hook(&match_end_func, END_FUNC_HOOK);
  85 }