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(int size)
  36 {
  37         total_size -= size;
  38 }
  39
  40 static void match_declarations(struct symbol *sym)
  41 {
  42         struct symbol *base;
  43         const char *name;
  44
  45         base = get_base_type(sym);
  46         if (sym->ctype.modifiers & MOD_STATIC)
  47                 return;
  48         name = sym->ident->name;
  49         total_size += base->bit_size;
  50         if (total_size > max_size) {
  51                 max_size = total_size;
  52                 max_lineno = get_lineno();
  53         }
  54         if (base->bit_size >= MAX_ALLOWED * 8) {
  55                 complained = 1;
  56                 sm_msg("warn: '%s' puts %d bytes on stack", name, base->bit_size / 8);
  57         }
  58         add_scope_hook((scope_hook *)&scope_end, INT_PTR(base->bit_size));
  59 }
  60
  61 static void match_end_func(struct symbol *sym)
  62 {
  63         if (__inline_fn)
  64                 return;
  65
  66         if ((max_size >= MAX_ALLOWED * 8) && !complained) {
  67                 sm_printf("%s:%d %s() ", get_filename(), max_lineno, get_function());
  68                 sm_printf("warn: function puts %d bytes on stack\n", max_size / 8);
  69         }
  70         total_size = 0;
  71         complained = 0;
  72         max_size = 0;
  73         max_lineno = 0;
  74 }
  75
  76 void check_stack(int id)
  77 {
  78         if (option_project != PROJ_KERNEL || !option_spammy)
  79                 return;
  80
  81         my_id = id;
  82         add_hook(&match_declarations, DECLARATION_HOOK);
  83         add_hook(&match_end_func, END_FUNC_HOOK);
  84 }