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 (__in_fake_assign)
  50                 return;
  51         if (get_param_num_from_sym(sym) < 0)
  52                 return;
  53         set_state(my_id, name, sym, state);
  54 }
  55
  56 /*
  57  * This relies on the fact that these states are stored so that
  58  * foo->bar is before foo->bar->baz.
  59  */
  60 static int parent_set(struct string_list *list, const char *name)
  61 {
  62         char *tmp;
  63         int len;
  64         int ret;
  65
  66         FOR_EACH_PTR(list, tmp) {
  67                 len = strlen(tmp);
  68                 ret = strncmp(tmp, name, len);
  69                 if (ret < 0)
  70                         continue;
  71                 if (ret > 0)
  72                         return 0;
  73                 if (name[len] == '-')
  74                         return 1;
  75         } END_FOR_EACH_PTR(tmp);
  76
  77         return 0;
  78 }
  79
  80 static void print_return_value_param(int return_id, char *return_ranges, struct expression *expr)
  81 {
  82         struct stree *stree;
  83         struct sm_state *sm;
  84         struct smatch_state *extra;
  85         int param;
  86         struct range_list *rl;
  87         const char *param_name;
  88         struct string_list *set_list = NULL;
  89         char *math_str;
  90         char buf[256];
  91         sval_t sval;
  92
  93         stree = __get_cur_stree();
  94
  95         FOR_EACH_MY_SM(my_id, stree, sm) {
  96                 if (!estate_rl(sm->state))
  97                         continue;
  98                 extra = get_state(SMATCH_EXTRA, sm->name, sm->sym);
  99                 if (!estate_rl(extra))
 100                         continue;
 101                 rl = rl_intersection(estate_rl(sm->state), estate_rl(extra));
 102                 if (!rl)
 103                         continue;
 104
 105                 param = get_param_num_from_sym(sm->sym);
 106                 if (param < 0)
 107                         continue;
 108                 param_name = get_param_name(sm);
 109                 if (!param_name)
 110                         continue;
 111                 if (strcmp(param_name, "$") == 0)
 112                         continue;
 113
 114                 if (rl_to_sval(rl, &sval)) {
 115                         insert_string(&set_list, (char *)sm->name);
 116                         sql_insert_return_states(return_id, return_ranges,
 117                                         param_has_filter_data(sm) ? ADDED_VALUE : PARAM_SET,
 118                                         param, param_name, show_rl(rl));
 119                         continue;
 120                 }
 121
 122                 math_str = get_value_in_terms_of_parameter_math_var_sym(sm->name, sm->sym);
 123                 if (math_str) {
 124                         snprintf(buf, sizeof(buf), "%s[%s]", show_rl(rl), math_str);
 125                         insert_string(&set_list, (char *)sm->name);
 126                         sql_insert_return_states(return_id, return_ranges,
 127                                         param_has_filter_data(sm) ? ADDED_VALUE : PARAM_SET,
 128                                         param, param_name, buf);
 129                         continue;
 130                 }
 131
 132                 /* no useful information here. */
 133                 if (is_whole_rl(rl) && parent_set(set_list, sm->name))
 134                         continue;
 135                 insert_string(&set_list, (char *)sm->name);
 136
 137                 sql_insert_return_states(return_id, return_ranges,
 138                                          param_has_filter_data(sm) ? ADDED_VALUE : PARAM_SET,
 139                                          param, param_name, show_rl(rl));
 140
 141         } END_FOR_EACH_SM(sm);
 142
 143         free_ptr_list((struct ptr_list **)&set_list);
 144 }
 145
 146 int param_was_set(struct expression *expr)
 147 {
 148         if (get_state_expr(my_id, expr))
 149                 return 1;
 150         return 0;
 151 }
 152
 153 void register_param_set(int id)
 154 {
 155         my_id = id;
 156
 157         add_extra_mod_hook(&extra_mod_hook);
 158         add_unmatched_state_hook(my_id, &unmatched_state);
 159         add_merge_hook(my_id, &merge_estates);
 160         add_split_return_callback(&print_return_value_param);
 161 }
 162