smatch_strings.c

   1 /*
   2  * Copyright (C) 2015 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 #include "smatch.h"
  19 #include "smatch_slist.h"
  20
  21 static int my_id;
  22
  23 static void match_strcpy(const char *fn, struct expression *expr, void *unused)
  24 {
  25         struct expression *dest, *src;
  26
  27         dest = get_argument_from_call_expr(expr->args, 0);
  28         src = get_argument_from_call_expr(expr->args, 1);
  29         src = strip_expr(src);
  30         if (src->type == EXPR_STRING)
  31                 set_state_expr(my_id, dest, alloc_state_str(src->string->data));
  32 }
  33
  34 struct state_list *get_strings(struct expression *expr)
  35 {
  36         struct state_list *ret = NULL;
  37         struct smatch_state *state;
  38         struct sm_state *sm;
  39
  40         expr = strip_expr(expr);
  41         if (expr->type == EXPR_STRING) {
  42                 state = alloc_state_str(expr->string->data);
  43                 sm = alloc_sm_state(my_id, expr->string->data, NULL, state);
  44                 add_ptr_list(&ret, sm);
  45                 return ret;
  46         }
  47
  48         if (expr->type == EXPR_CONDITIONAL ||
  49             expr->type == EXPR_SELECT) {
  50                 struct state_list *true_strings = NULL;
  51                 struct state_list *false_strings = NULL;
  52
  53                 if (known_condition_true(expr->conditional))
  54                         return get_strings(expr->cond_true);
  55                 if (known_condition_false(expr->conditional))
  56                         return get_strings(expr->cond_false);
  57
  58                 true_strings = get_strings(expr->cond_true);
  59                 false_strings = get_strings(expr->cond_false);
  60                 concat_ptr_list((struct ptr_list *)true_strings, (struct ptr_list **)&false_strings);
  61                 free_slist(&true_strings);
  62                 return false_strings;
  63         }
  64
  65         sm = get_sm_state_expr(my_id, expr);
  66         if (!sm)
  67                 return NULL;
  68
  69         return clone_slist(sm->possible);
  70 }
  71
  72 static void match_assignment(struct expression *expr)
  73 {
  74         struct state_list *slist;
  75         struct sm_state *sm;
  76
  77         if (expr->op != '=')
  78                 return;
  79
  80         slist = get_strings(strip_expr(expr->right));
  81         if (!slist)
  82                 return;
  83
  84         if (ptr_list_size((struct ptr_list *)slist) == 1) {
  85                 sm = first_ptr_list((struct ptr_list *)slist);
  86                 set_state_expr(my_id, expr->left, sm->state);
  87                 return;
  88         }
  89 }
  90
  91 void register_strings(int id)
  92 {
  93         my_id = id;
  94
  95         add_function_hook("strcpy", &match_strcpy, NULL);
  96         add_function_hook("strlcpy", &match_strcpy, NULL);
  97         add_function_hook("strncpy", &match_strcpy, NULL);
  98
  99         add_hook(&match_assignment, ASSIGNMENT_HOOK);
 100
 101 }