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 #define MAX_ALLOWED 1000
  26
  27 static void scope_end(int size)
  28 {
  29         total_size -= size;
  30 }
  31
  32 static void match_declarations(struct symbol *sym)
  33 {
  34         struct symbol *base;
  35         const char *name;
  36
  37         base = get_base_type(sym);
  38         if (sym->ctype.modifiers & MOD_STATIC)
  39                 return;
  40         name = sym->ident->name;
  41         total_size += base->bit_size;
  42         if (total_size > max_size) {
  43                 max_size = total_size;
  44                 max_lineno = get_lineno();
  45         }
  46         if (base->bit_size >= MAX_ALLOWED * 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, INT_PTR(base->bit_size));
  51 }
  52
  53 static void match_end_func(struct symbol *sym)
  54 {
  55         if (__inline_fn)
  56                 return;
  57
  58         if ((max_size >= MAX_ALLOWED * 8) && !complained) {
  59                 sm_printf("%s:%d %s() ", get_filename(), max_lineno, get_function());
  60                 sm_printf("warn: function puts %d bytes on stack\n", max_size / 8);
  61         }
  62         total_size = 0;
  63         complained = 0;
  64         max_size = 0;
  65         max_lineno = 0;
  66 }
  67
  68 void check_stack(int id)
  69 {
  70         if (option_project != PROJ_KERNEL || !option_spammy)
  71                 return;
  72
  73         my_id = id;
  74         add_hook(&match_declarations, DECLARATION_HOOK);
  75         add_hook(&match_end_func, END_FUNC_HOOK);
  76 }