check_resource_size.c

   1 /*
   2  * smatch/check_resource_size.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11
  12 static int my_id;
  13 extern int check_assigned_expr_id;
  14
  15 static int is_probably_ok(struct expression *expr)
  16 {
  17         expr = strip_expr(expr);
  18
  19         if (expr->type == EXPR_BINOP)
  20                 return 1;
  21         if (expr->type == EXPR_SIZEOF)
  22                 return 1;
  23
  24         return 0;
  25 }
  26
  27 static void verify_size_expr(struct expression *expr)
  28 {
  29         if (expr->type != EXPR_BINOP)
  30                 return;
  31         if (expr->op != '-')
  32                 return;
  33         if (is_probably_ok(expr->left))
  34                 return;
  35         if (is_probably_ok(expr->right))
  36                 return;
  37         sm_msg("warn: consider using resource_size() here");
  38 }
  39
  40 static void handle_assigned_expr(struct expression *expr)
  41 {
  42         struct smatch_state *state;
  43
  44         state = get_state_expr(check_assigned_expr_id, expr);
  45         if (!state || !state->data)
  46                 return;
  47         expr = (struct expression *)state->data;
  48         verify_size_expr(expr);
  49 }
  50
  51 static void match_resource(const char *fn, struct expression *expr, void *_arg_no)
  52 {
  53         struct expression *arg_expr;
  54         int arg_no = PTR_INT(_arg_no);
  55
  56         arg_expr = get_argument_from_call_expr(expr->args, arg_no);
  57         arg_expr = strip_expr(arg_expr);
  58         if (!arg_expr)
  59                 return;
  60
  61         if (arg_expr->type == EXPR_SYMBOL) {
  62                 handle_assigned_expr(arg_expr);
  63                 return;
  64         }
  65         verify_size_expr(arg_expr);
  66 }
  67
  68 void check_resource_size(int id)
  69 {
  70         my_id = id;
  71
  72         if (option_project != PROJ_KERNEL)
  73                 return;
  74
  75         add_function_hook("ioremap_nocache", &match_resource, (void *)1);
  76         add_function_hook("ioremap", &match_resource, (void *)1);
  77         add_function_hook("__request_region", &match_resource, (void *)2);
  78         add_function_hook("__release_region", &match_resource, (void *)2);
  79         add_function_hook("__devm_request_region", &match_resource, (void *)3);
  80         add_function_hook("__devm_release_region", &match_resource, (void *)3);
  81 }