check_unwind.c

   1 /*
   2  * smatch/check_unwind.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * This is a kernel check to make sure we unwind everything on
  12  * on errors.
  13  *
  14  */
  15
  16 #include "smatch.h"
  17 #include "smatch_extra.h"
  18 #include "smatch_slist.h"
  19
  20 #define EBUSY 16
  21 #define MAX_ERRNO 4095
  22
  23 static int my_id;
  24
  25 STATE(allocated);
  26 STATE(unallocated);
  27
  28 static void request_granted(const char *fn, struct expression *call_expr,
  29                         struct expression *assign_expr, void *_arg_no)
  30 {
  31         struct expression *arg_expr;
  32         int arg_no = (int)_arg_no;
  33
  34         if (arg_no == -1)
  35                 arg_expr = assign_expr->left;
  36         else
  37                 arg_expr = get_argument_from_call_expr(call_expr->args, arg_no);
  38         set_state_expr(my_id, arg_expr, &allocated);
  39 }
  40
  41 static void request_denied(const char *fn, struct expression *call_expr,
  42                         struct expression *assign_expr, void *_arg_no)
  43 {
  44         struct expression *arg_expr;
  45         int arg_no = (int)_arg_no;
  46
  47         if (arg_no == -1)
  48                 arg_expr = assign_expr->left;
  49         else
  50                 arg_expr = get_argument_from_call_expr(call_expr->args, arg_no);
  51         set_state_expr(my_id, arg_expr, &unallocated);
  52 }
  53
  54 static void match_release(const char *fn, struct expression *expr, void *_arg_no)
  55 {
  56         struct expression *arg_expr;
  57         int arg_no = (int)_arg_no;
  58
  59         arg_expr = get_argument_from_call_expr(expr->args, arg_no);
  60         if (!get_state_expr(my_id, arg_expr))
  61                 return;
  62         set_state_expr(my_id, arg_expr, &unallocated);
  63 }
  64
  65 static int func_returns_int()
  66 {
  67         struct symbol *type;
  68
  69         type = get_base_type(cur_func_sym);
  70         if (!type || type->type != SYM_FN)
  71                 return 0;
  72         type = get_base_type(type);
  73         if (type->ctype.base_type == &int_type) {
  74                 return 1;
  75         }
  76         return 0;
  77 }
  78
  79 static void match_return(struct expression *ret_value)
  80 {
  81         struct state_list *slist;
  82         struct sm_state *tmp;
  83
  84         if (!func_returns_int())
  85                 return;
  86         if (!implied_not_equal(ret_value, 0))
  87                 return;
  88
  89         slist = get_all_states(my_id);
  90         FOR_EACH_PTR(slist, tmp) {
  91                 if (slist_has_state(tmp->possible, &allocated))
  92                         sm_msg("warn: '%s' was not released on error", tmp->name);
  93         } END_FOR_EACH_PTR(tmp);
  94         free_slist(&slist);
  95 }
  96
  97 void check_unwind(int id)
  98 {
  99         if (option_project != PROJ_KERNEL)
 100                 return;
 101         my_id = id;
 102
 103         return_implies_state("request_resource", 0, 0, &request_granted, INT_PTR(1));
 104         return_implies_state("request_resource", -EBUSY, -EBUSY, &request_denied, INT_PTR(1));
 105         add_function_hook("release_resource", &match_release, INT_PTR(0));
 106
 107         return_implies_state("__request_region", 1, POINTER_MAX, &request_granted, INT_PTR(1));
 108         return_implies_state("__request_region", 0, 0, &request_denied, INT_PTR(1));
 109         add_function_hook("__release_region", &match_release, INT_PTR(1));
 110
 111         return_implies_state("ioremap", 1, POINTER_MAX, &request_granted, INT_PTR(-1));
 112         return_implies_state("ioremap", 0, 0, &request_denied, INT_PTR(-1));
 113         add_function_hook("iounmap", &match_release, INT_PTR(0));
 114
 115         return_implies_state("pci_iomap", 1, POINTER_MAX, &request_granted, INT_PTR(-1));
 116         return_implies_state("pci_iomap", 0, 0, &request_denied, INT_PTR(-1));
 117         add_function_hook("pci_iounmap", &match_release, INT_PTR(1));
 118
 119         return_implies_state("__create_workqueue_key", 1, POINTER_MAX, &request_granted,
 120                         INT_PTR(-1));
 121         return_implies_state("__create_workqueue_key", 0, 0, &request_denied, INT_PTR(-1));
 122         add_function_hook("destroy_workqueue", &match_release, INT_PTR(0));
 123
 124         return_implies_state("request_irq", 0, 0, &request_granted, INT_PTR(0));
 125         return_implies_state("request_irq", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
 126         add_function_hook("free_irq", &match_release, INT_PTR(0));
 127
 128         return_implies_state("register_netdev", 0, 0, &request_granted, INT_PTR(0));
 129         return_implies_state("register_netdev", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
 130         add_function_hook("unregister_netdev", &match_release, INT_PTR(0));
 131
 132         return_implies_state("misc_register", 0, 0, &request_granted, INT_PTR(0));
 133         return_implies_state("misc_register", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
 134         add_function_hook("misc_deregister", &match_release, INT_PTR(0));
 135
 136         add_hook(&match_return, RETURN_HOOK);
 137 }