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 struct symbol *this_func;
  20 static int err_ptr = 0;
  21 static int returns_null = 0;
  22
  23 static void match_function_def(struct symbol *sym)
  24 {
  25         this_func = sym;
  26 }
  27
  28 static void match_err_ptr(const char *fn, struct expression *expr, void *info)
  29 {
  30         struct expression *arg;
  31         int value;
  32
  33         arg = get_argument_from_call_expr(expr->args, 0);
  34         value = get_implied_value(arg);
  35         if (value != UNDEFINED && value < -4095)
  36                 smatch_msg("error: the error code is too large for ERR_PTR");
  37         if (!err_ptr)
  38                 smatch_msg("info:  returns_err_ptr");
  39         err_ptr = 1;
  40 }
  41
  42 static void match_return(struct statement *stmt)
  43 {
  44         if (get_implied_value(stmt->ret_value) != 0)
  45                 return;
  46         if (!returns_null)
  47                 smatch_msg("info:  returns_null");
  48         returns_null = 1;
  49 }
  50
  51 static void match_end_func(struct symbol *sym)
  52 {
  53         err_ptr = 0;
  54         returns_null = 0;
  55 }
  56
  57 void check_err_ptr(int id)
  58 {
  59         my_id = id;
  60         add_hook(&match_function_def, FUNC_DEF_HOOK);
  61         add_function_hook("ERR_PTR", &match_err_ptr, NULL);
  62         add_hook(&match_return, RETURN_HOOK);
  63         add_hook(&match_end_func, END_FUNC_HOOK);
  64 }