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 complained;
  24
  25 static void scope_end(int size)
  26 {
  27         total_size -= size;
  28 }
  29
  30 static void match_declarations(struct symbol *sym)
  31 {
  32         struct symbol *base;
  33         const char *name;
  34
  35         base = get_base_type(sym);
  36         if (sym->ctype.modifiers & MOD_STATIC)
  37                 return;
  38         name = sym->ident->name;
  39         total_size += base->bit_size;
  40         if (total_size > max_size) {
  41                 max_size = total_size;
  42                 max_lineno = get_lineno();
  43         }
  44         if (base->bit_size >= 500 * 8) {
  45                 complained = 1;
  46                 sm_msg("warn: '%s' puts %d bytes on stack", name, base->bit_size / 8);
  47         }
  48         add_scope_hook((scope_hook *)&scope_end, INT_PTR(base->bit_size));
  49 }
  50
  51 static void match_end_func(struct symbol *sym)
  52 {
  53         if ((max_size >= 500 * 8) && !complained) {
  54                 sm_printf("%s:%d %s() ", get_filename(), max_lineno, get_function());
  55                 sm_printf("warn: function puts %d bytes on stack\n", max_size / 8);
  56         }
  57         total_size = 0;
  58         complained = 0;
  59         max_size = 0;
  60         max_lineno = 0;
  61 }
  62
  63 void check_stack(int id)
  64 {
  65         if (option_project != PROJ_KERNEL)
  66                 return;
  67
  68         my_id = id;
  69         add_hook(&match_declarations, DECLARATION_HOOK);
  70         add_hook(&match_end_func, END_FUNC_HOOK);
  71 }