smatch_capped.c

   1 /*
   2  * smatch/smatch_capped.c
   3  *
   4  * Copyright (C) 2011 Oracle.  All rights reserved.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * This is trying to make a list of the variables which
  12  * have capped values.  Sometimes we don't know what the
  13  * cap is, for example if we are comparing variables but
  14  * we don't know the values of the variables.  In that
  15  * case we only know that our variable is capped and we
  16  * sort that information here.
  17  */
  18
  19 #include "smatch.h"
  20 #include "smatch_slist.h"
  21
  22 static int my_id;
  23
  24 STATE(capped);
  25 STATE(uncapped);
  26
  27 static int is_capped_macro(struct expression *expr)
  28 {
  29         char *name;
  30
  31         name = get_macro_name(expr->pos);
  32         if (!name)
  33                 return 0;
  34
  35         if (strcmp(name, "min") == 0)
  36                 return 1;
  37         if (strcmp(name, "MIN") == 0)
  38                 return 1;
  39         if (strcmp(name, "min_t") == 0)
  40                 return 1;
  41
  42         return 0;
  43 }
  44
  45 int is_capped(struct expression *expr)
  46 {
  47         sval_t dummy;
  48
  49         expr = strip_expr(expr);
  50         if (!expr)
  51                 return 0;
  52
  53         if (get_implied_value(expr, &dummy))
  54                 return 1;
  55
  56         if (is_capped_macro(expr))
  57                 return 1;
  58
  59         if (expr->type == EXPR_BINOP) {
  60                 if (expr->op == '&')
  61                         return 1;
  62                 if (expr->op == SPECIAL_RIGHTSHIFT)
  63                         return 1;
  64                 if (expr->op == '%')
  65                         return is_capped(expr->right);
  66                 if (!is_capped(expr->left))
  67                         return 0;
  68                 if (expr->op == '/')
  69                         return 1;
  70                 if (!is_capped(expr->right))
  71                         return 0;
  72                 return 1;
  73         }
  74         if (get_state_expr(my_id, expr) == &capped)
  75                 return 1;
  76         return 0;
  77 }
  78
  79 void set_param_capped_data(const char *name, struct symbol *sym, char *key, char *value)
  80 {
  81         char fullname[256];
  82
  83         if (strncmp(key, "$$", 2))
  84                 return;
  85         snprintf(fullname, 256, "%s%s", name, key + 2);
  86         set_state(my_id, fullname, sym, &capped);
  87 }
  88
  89 static void match_condition(struct expression *expr)
  90 {
  91         struct smatch_state *left_true = NULL;
  92         struct smatch_state *left_false = NULL;
  93         struct smatch_state *right_true = NULL;
  94         struct smatch_state *right_false = NULL;
  95
  96
  97         if (expr->type != EXPR_COMPARE)
  98                 return;
  99
 100         switch (expr->op) {
 101         case '<':
 102         case SPECIAL_LTE:
 103         case SPECIAL_UNSIGNED_LT:
 104         case SPECIAL_UNSIGNED_LTE:
 105                 left_true = &capped;
 106                 right_false = &capped;
 107                 break;
 108         case '>':
 109         case SPECIAL_GTE:
 110         case SPECIAL_UNSIGNED_GT:
 111         case SPECIAL_UNSIGNED_GTE:
 112                 left_false = &capped;
 113                 right_true = &capped;
 114                 break;
 115         case SPECIAL_EQUAL:
 116                 left_true = &capped;
 117                 right_true = &capped;
 118                 break;
 119         case SPECIAL_NOTEQUAL:
 120                 left_false = &capped;
 121                 right_false = &capped;
 122                 break;
 123
 124         default:
 125                 return;
 126         }
 127
 128         set_true_false_states_expr(my_id, expr->right, right_true, right_false);
 129         set_true_false_states_expr(my_id, expr->left, left_true, left_false);
 130 }
 131
 132 static void match_assign(struct expression *expr)
 133 {
 134         if (is_capped(expr->right)) {
 135                 set_state_expr(my_id, expr->left, &capped);
 136         } else {
 137                 if (get_state_expr(my_id, expr->left))
 138                         set_state_expr(my_id, expr->left, &uncapped);
 139         }
 140 }
 141
 142 static void match_caller_info(struct expression *expr)
 143 {
 144         struct expression *tmp;
 145         int i;
 146
 147         i = 0;
 148         FOR_EACH_PTR(expr->args, tmp) {
 149                 if (is_capped(tmp))
 150                         sql_insert_caller_info(expr, CAPPED_DATA, i, "$$", "1");
 151                 i++;
 152         } END_FOR_EACH_PTR(tmp);
 153 }
 154
 155 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
 156 {
 157         if (state != &capped)
 158                 return;
 159         sql_insert_caller_info(call, CAPPED_DATA, param, printed_name, "1");
 160 }
 161
 162 void register_capped(int id)
 163 {
 164         my_id = id;
 165
 166         add_definition_db_callback(set_param_capped_data, CAPPED_DATA);
 167         add_hook(&match_condition, CONDITION_HOOK);
 168         add_hook(&match_assign, ASSIGNMENT_HOOK);
 169
 170         add_hook(&match_caller_info, FUNCTION_CALL_HOOK);
 171         add_member_info_callback(my_id, struct_member_callback);
 172 }