check_return_enomem.c

   1 /*
   2  * smatch/check_return_enomem.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * Complains about places that return -1 instead of -ENOMEM
  12  */
  13
  14 #include "smatch.h"
  15 #include "smatch_slist.h"
  16 #include "smatch_extra.h"
  17
  18 #define ENOMEM 12
  19
  20 static int my_id;
  21
  22 STATE(enomem);
  23 STATE(ok);
  24
  25 static void ok_to_use(struct sm_state *sm, struct expression *mod_expr)
  26 {
  27         if (sm->state != &ok)
  28                 set_state(my_id, sm->name, sm->sym, &ok);
  29 }
  30
  31 static void allocation_succeeded(const char *fn, struct expression *call_expr,
  32                                 struct expression *assign_expr, void *unused)
  33 {
  34         set_state_expr(my_id, assign_expr->left, &ok);
  35 }
  36
  37 static void allocation_failed(const char *fn, struct expression *call_expr,
  38                         struct expression *assign_expr, void *_arg_no)
  39 {
  40         set_state_expr(my_id, assign_expr->left, &enomem);
  41 }
  42
  43 static void match_return(struct expression *ret_value)
  44 {
  45         struct sm_state *sm;
  46         struct state_list *slist;
  47         sval_t sval;
  48
  49         if (!ret_value)
  50                 return;
  51         if (returns_unsigned(cur_func_sym))
  52                 return;
  53         if (returns_pointer(cur_func_sym))
  54                 return;
  55         if (!get_value(ret_value, &sval) || sval.value != -1)
  56                 return;
  57         if (get_macro_name(ret_value->pos))
  58                 return;
  59
  60         slist = get_all_states(my_id);
  61
  62         FOR_EACH_PTR(slist, sm) {
  63                 if (sm->state == &enomem) {
  64                         sm_msg("warn: returning -1 instead of -ENOMEM is sloppy");
  65                         goto out;
  66                 }
  67         } END_FOR_EACH_PTR(sm);
  68
  69 out:
  70         free_slist(&slist);
  71 }
  72
  73 void check_return_enomem(int id)
  74 {
  75         if (option_project != PROJ_KERNEL)
  76                 return;
  77
  78         my_id = id;
  79         return_implies_state("kmalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  80         return_implies_state("kmalloc", 0, 0, &allocation_failed, INT_PTR(0));
  81         return_implies_state("kzalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  82         return_implies_state("kzalloc", 0, 0, &allocation_failed, INT_PTR(0));
  83         return_implies_state("kcalloc", valid_ptr_min, valid_ptr_max, &allocation_succeeded, INT_PTR(0));
  84         return_implies_state("kcalloc", 0, 0, &allocation_failed, INT_PTR(0));
  85         add_hook(&match_return, RETURN_HOOK);
  86         add_modification_hook(my_id, &ok_to_use);
  87 }