check_err_ptr.c

   1 /*
   2  * sparse/check_err_ptr.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11 #include "smatch_slist.h"
  12
  13 static int my_id;
  14
  15 static int err_ptr = 0;
  16 static int returns_null = 0;
  17
  18 static void match_err_ptr(struct expression *expr)
  19 {
  20         expr = strip_expr(expr);
  21         if (!expr)
  22                 return;
  23         if (expr->type != EXPR_CALL)
  24                 return;
  25
  26         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
  27                 return;
  28         if (!strcmp(expr->fn->symbol->ident->name, "ERR_PTR"))
  29                 err_ptr = 1;
  30 }
  31
  32 extern int check_assigned_expr_id;
  33 static void match_return(struct expression *ret_value)
  34 {
  35         struct state_list *slist;
  36         struct sm_state *tmp;
  37         sval_t sval;
  38
  39         if (__inline_fn)
  40                 return;
  41         match_err_ptr(ret_value);
  42         slist = get_possible_states_expr(check_assigned_expr_id, ret_value);
  43         FOR_EACH_PTR(slist, tmp) {
  44                 if (tmp->state == &undefined || tmp->state == &merged)
  45                         continue;
  46                 match_err_ptr((struct expression *)tmp->state->data);
  47         } END_FOR_EACH_PTR(tmp);
  48
  49         if (get_implied_value(ret_value, &sval)) {
  50                 if (sval.value == 0)
  51                         returns_null = 1;
  52         }
  53 }
  54
  55 static void match_end_func(struct symbol *sym)
  56 {
  57         if (__inline_fn)
  58                 return;
  59         if (err_ptr)
  60                 sm_info("returns_err_ptr");
  61         err_ptr = 0;
  62         returns_null = 0;
  63 }
  64
  65 void check_err_ptr(int id)
  66 {
  67         if (option_project != PROJ_KERNEL)
  68                 return;
  69         if (!option_info)
  70                 return;
  71
  72         my_id = id;
  73         add_hook(&match_return, RETURN_HOOK);
  74         add_hook(&match_end_func, END_FUNC_HOOK);
  75 }