smatch_param_set.c

   1 /*
   2  * Copyright (C) 2012 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 is for functions like:
  20  *
  21  * int foo(int *x)
  22  * {
  23  *      if (*x == 42) {
  24  *              *x = 0;
  25  *              return 1;
  26  *      }
  27  *      return 0;
  28  * }
  29  *
  30  * If we return 1 that means the value of *x has been set to 0.  If we return
  31  * 0 then we have left *x alone.
  32  *
  33  */
  34
  35 #include "scope.h"
  36 #include "smatch.h"
  37 #include "smatch_slist.h"
  38 #include "smatch_extra.h"
  39
  40 static int my_id;
  41
  42 static struct smatch_state *unmatched_state(struct sm_state *sm)
  43 {
  44         return alloc_estate_empty();
  45 }
  46
  47 static void extra_mod_hook(const char *name, struct symbol *sym, struct smatch_state *state)
  48 {
  49         if (get_param_num_from_sym(sym) < 0)
  50                 return;
  51         set_state(my_id, name, sym, state);
  52 }
  53
  54 /*
  55  * This relies on the fact that these states are stored so that
  56  * foo->bar is before foo->bar->baz.
  57  */
  58 static int parent_set(struct string_list *list, const char *name)
  59 {
  60         char *tmp;
  61         int len;
  62         int ret;
  63
  64         FOR_EACH_PTR(list, tmp) {
  65                 len = strlen(tmp);
  66                 ret = strncmp(tmp, name, len);
  67                 if (ret < 0)
  68                         continue;
  69                 if (ret > 0)
  70                         return 0;
  71                 if (name[len] == '-')
  72                         return 1;
  73         } END_FOR_EACH_PTR(tmp);
  74
  75         return 0;
  76 }
  77
  78 static void print_return_value_param(int return_id, char *return_ranges, struct expression *expr)
  79 {
  80         struct stree *stree;
  81         struct sm_state *sm;
  82         struct smatch_state *extra;
  83         int param;
  84         struct range_list *rl;
  85         const char *param_name;
  86         struct string_list *set_list = NULL;
  87
  88         stree = __get_cur_stree();
  89
  90         FOR_EACH_MY_SM(my_id, stree, sm) {
  91                 if (!estate_rl(sm->state))
  92                         continue;
  93                 extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  94                 if (!estate_rl(extra))
  95                         continue;
  96                 rl = rl_intersection(estate_rl(sm->state), estate_rl(extra));
  97                 if (!rl)
  98                         continue;
  99
 100                 param = get_param_num_from_sym(sm->sym);
 101                 if (param < 0)
 102                         continue;
 103                 param_name = get_param_name(sm);
 104                 if (!param_name)
 105                         continue;
 106                 if (strcmp(param_name, "$$") == 0)
 107                         continue;
 108
 109                 /* no useful information here. */
 110                 if (is_whole_rl(rl) && parent_set(set_list, sm->name))
 111                         continue;
 112                 insert_string(&set_list, (char *)sm->name);
 113
 114                 sql_insert_return_states(return_id, return_ranges, ADDED_VALUE,
 115                                          param, param_name, show_rl(rl));
 116         } END_FOR_EACH_SM(sm);
 117
 118         free_ptr_list((struct ptr_list **)&set_list);
 119 }
 120
 121 int param_was_set(struct expression *expr)
 122 {
 123         if (get_state_expr(my_id, expr))
 124                 return 1;
 125         return 0;
 126 }
 127
 128 void register_param_set(int id)
 129 {
 130         my_id = id;
 131
 132         add_extra_mod_hook(&extra_mod_hook);
 133         add_unmatched_state_hook(my_id, &unmatched_state);
 134         add_merge_hook(my_id, &merge_estates);
 135         add_split_return_callback(&print_return_value_param);
 136 }
 137