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 /*
  11  * Functions should never return both NULL and ERR_PTR().
  12  */
  13
  14 #include "smatch.h"
  15 #include "smatch_slist.h"
  16
  17 static int my_id;
  18
  19 static int err_ptr = 0;
  20 static int returns_null = 0;
  21
  22 static void match_err_ptr(struct expression *expr)
  23 {
  24         expr = strip_expr(expr);
  25         if (!expr)
  26                 return;
  27         if (expr->type != EXPR_CALL)
  28                 return;
  29
  30         if (expr->fn->type != EXPR_SYMBOL || !expr->fn->symbol)
  31                 return;
  32         if (!strcmp(expr->fn->symbol->ident->name, "ERR_PTR"))
  33                 err_ptr = 1;
  34 }
  35
  36 extern int check_assigned_expr_id;
  37 static void match_return(struct expression *ret_value)
  38 {
  39         struct state_list *slist;
  40         struct sm_state *tmp;
  41         long long val;
  42
  43         match_err_ptr(ret_value);
  44         slist = get_possible_states_expr(check_assigned_expr_id, ret_value);
  45         FOR_EACH_PTR(slist, tmp) {
  46                 if (tmp->state == &undefined || tmp->state == &merged)
  47                         continue;
  48                 match_err_ptr((struct expression *)tmp->state->data);
  49         } END_FOR_EACH_PTR(tmp);
  50
  51         if (get_implied_value(ret_value, &val)) {
  52                 if (val == 0)
  53                         returns_null = 1;
  54         }
  55 }
  56
  57 static void match_end_func(struct symbol *sym)
  58 {
  59         if (returns_null && err_ptr)
  60                 sm_msg("warn:  returns both null and ERR_PTR.");
  61         if (err_ptr)
  62                 sm_msg("info:  returns_err_ptr");
  63         err_ptr = 0;
  64         returns_null = 0;
  65 }
  66
  67 void check_err_ptr(int id)
  68 {
  69         if (!option_spammy || option_project != PROJ_KERNEL)
  70                 return;
  71
  72         my_id = id;
  73         add_hook(&match_return, RETURN_HOOK);
  74         add_hook(&match_end_func, END_FUNC_HOOK);
  75 }