check_frees_param_strict.c

   1 /*
   2  * Copyright (C) 2014 Oracle.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * This file is sort of like check_dereferences_param.c.  In theory the one
  20  * difference should be that the param is NULL it should still be counted as a
  21  * free.  But for now I don't handle that case.
  22  */
  23
  24 #include "smatch.h"
  25 #include "smatch_extra.h"
  26 #include "smatch_slist.h"
  27
  28 static int my_id;
  29
  30 STATE(ignore);
  31
  32 static struct smatch_state *unmatched_state(struct sm_state *sm)
  33 {
  34         if (parent_is_null_var_sym(sm->name, sm->sym))
  35                 return sm->state;
  36         return &undefined;
  37 }
  38
  39 static void set_ignore(struct sm_state *sm, struct expression *mod_expr)
  40 {
  41         if (sm->sym && sm->sym->ident &&
  42             strcmp(sm->sym->ident->name, sm->name) == 0)
  43                 return;
  44         set_state(my_id, sm->name, sm->sym, &ignore);
  45 }
  46
  47 void track_freed_param(struct expression *expr, struct smatch_state *state)
  48 {
  49         const char *key;
  50         int param;
  51
  52         param = get_param_key_from_expr(expr, NULL, &key);
  53         if (param < 0)
  54                 return;
  55         if (param_was_set(expr))
  56                 return;
  57
  58         set_state_expr(my_id, expr, state);
  59 }
  60
  61 void track_freed_param_var_sym(const char *name, struct symbol *sym,
  62                                struct smatch_state *state)
  63 {
  64         struct expression *tmp;
  65
  66         tmp = get_assigned_expr_name_sym(name, sym);
  67         if (tmp)
  68                 track_freed_param(tmp, state);
  69
  70         if (get_param_num_from_sym(sym) < 0)
  71                 return;
  72         /*
  73          * FIXME: some unpublished code made this apply to only '$' and I
  74          * don't remember why I would do that.  But there was probably
  75          * a reason.
  76          */
  77         if (param_was_set_var_sym(name, sym))
  78                 return;
  79
  80         set_state(my_id, name, sym, state);
  81 }
  82
  83 static int get_freed_type(struct sm_state *sm)
  84 {
  85         struct sm_state *tmp;
  86
  87         if (strcmp(sm->state->name, "freed") == 0)
  88                 return PARAM_FREED;
  89
  90         FOR_EACH_PTR(sm->possible, tmp) {
  91                 if (strcmp(tmp->state->name, "freed") == 0)
  92                         return MAYBE_FREED;
  93         } END_FOR_EACH_PTR(tmp);
  94
  95         return 0;
  96 }
  97
  98 static void return_freed_callback(int return_id, char *return_ranges,
  99                                  struct expression *returned_expr,
 100                                  int param,
 101                                  const char *printed_name,
 102                                  struct sm_state *sm)
 103 {
 104         int type;
 105
 106         type = get_freed_type(sm);
 107         if (!type)
 108                 return;
 109
 110         if (on_atomic_dec_path())
 111                 return;
 112
 113         sql_insert_return_states(return_id, return_ranges, type,
 114                                  param, printed_name, "");
 115 }
 116
 117 void check_frees_param_strict(int id)
 118 {
 119         my_id = id;
 120
 121         add_modification_hook(my_id, &set_ignore);
 122         add_return_info_callback(my_id, return_freed_callback);
 123         add_unmatched_state_hook(my_id, &unmatched_state);
 124 }