check_stack.c

   1 /*
   2  * smatch/check_stack.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * The kernel has a small stack so putting huge structs and arrays on the
  12  * stack is a bug.
  13  *
  14  */
  15
  16 #include "smatch.h"
  17
  18 static int my_id;
  19
  20 static int total_size;
  21 static int max_size;
  22 static int max_lineno;
  23 static int max_func_pos;
  24 static int complained;
  25
  26 static void scope_end(int size)
  27 {
  28         total_size -= size;
  29 }
  30
  31 static void match_declarations(struct symbol *sym)
  32 {
  33         struct symbol *base;
  34         const char *name;
  35
  36         base = get_base_type(sym);
  37         if (sym->ctype.modifiers & MOD_STATIC)
  38                 return;
  39         name = sym->ident->name;
  40         total_size += base->bit_size;
  41         if (total_size > max_size) {
  42                 max_size = total_size;
  43                 max_lineno = get_lineno();
  44                 max_func_pos = get_func_pos();
  45         }
  46         if (base->bit_size >= 500 * 8) {
  47                 complained = 1;
  48                 sm_msg("warn: '%s' puts %d bytes on stack", name, base->bit_size / 8);
  49         }
  50         add_scope_hook((scope_hook *)&scope_end, (void *)base->bit_size);
  51 }
  52
  53 static void match_end_func(struct symbol *sym)
  54 {
  55         if ((max_size >= 500 * 8) && !complained) {
  56                 sm_printf("%s +%d %s(%d) ", get_filename(), max_lineno, get_function(), max_func_pos);
  57                 sm_printf("warn: function puts %d bytes on stack\n", max_size / 8);
  58         }
  59         total_size = 0;
  60         complained = 0;
  61         max_size = 0;
  62         max_lineno = 0;
  63         max_func_pos = 0;
  64 }
  65
  66 void check_stack(int id)
  67 {
  68         if (option_project != PROJ_KERNEL)
  69                 return;
  70
  71         my_id = id;
  72         add_hook(&match_declarations, DECLARATION_HOOK);
  73         add_hook(&match_end_func, END_FUNC_HOOK);
  74 }