check_allocation_funcs.c

   1 /*
   2  * sparse/check_allocation_funcs.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <fcntl.h>
  11 #include <unistd.h>
  12 #include "parse.h"
  13 #include "smatch.h"
  14 #include "smatch_slist.h"
  15
  16 static int my_id;
  17
  18 /*
  19  * Print a list of functions that return newly allocated memory.
  20  */
  21
  22 static struct tracker_list *allocated;
  23
  24 static const char *allocation_funcs[] = {
  25         "kmalloc",
  26         "kzalloc",
  27         "kcalloc",
  28         NULL,
  29 };
  30
  31 static void match_allocation(const char *fn, struct expression *expr,
  32                              void *info)
  33 {
  34         char *left_name;
  35         struct symbol *left_sym;
  36
  37         left_name = expr_to_var_sym(expr->left, &left_sym);
  38         if (!left_name || !left_sym)
  39                 goto free;
  40         if (left_sym->ctype.modifiers &
  41             (MOD_NONLOCAL | MOD_STATIC | MOD_ADDRESSABLE))
  42                 goto free;
  43         add_tracker(&allocated, my_id, left_name, left_sym);
  44 free:
  45         free_string(left_name);
  46 }
  47
  48 static int returns_new_stuff = 0;
  49 static int returns_old_stuff = 0;
  50 static void match_return(struct expression *ret_value)
  51 {
  52         char *name;
  53         struct symbol *sym;
  54         sval_t tmp;
  55
  56         if (__inline_fn)
  57                 return;
  58         if (get_value(ret_value, &tmp) && tmp.value == 0)
  59                 return;
  60         returns_new_stuff = 1;
  61         name = expr_to_var_sym(ret_value, &sym);
  62         if (!name || !sym) {
  63                 returns_old_stuff = 1;
  64                 goto free;
  65         }
  66         if (!in_tracker_list(allocated, my_id, name, sym))
  67                 returns_old_stuff = 1;
  68 free:
  69         free_string(name);
  70 }
  71
  72 static void match_end_func(struct symbol *sym)
  73 {
  74         if (__inline_fn)
  75                 return;
  76         if (returns_new_stuff && !returns_old_stuff)
  77                 sm_info("allocation func");
  78         free_trackers_and_list(&allocated);
  79         returns_new_stuff = 0;
  80         returns_old_stuff = 0;
  81 }
  82
  83 void check_allocation_funcs(int id)
  84 {
  85         int i;
  86
  87         if (!option_info || option_project != PROJ_KERNEL)
  88                 return;
  89
  90         my_id = id;
  91         add_hook(&match_return, RETURN_HOOK);
  92         add_hook(&match_end_func, END_FUNC_HOOK);
  93         for (i = 0; allocation_funcs[i]; i++) {
  94                 add_function_assign_hook(allocation_funcs[i],
  95                                          &match_allocation, NULL);
  96         }
  97 }