check_assigned_expr.c

   1 /*
   2  * Copyright (C) 2009 Dan Carpenter.
   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 not a check.  It just saves an struct expression pointer
  20  * whenever something is assigned.  This can be used later on by other scripts.
  21  */
  22
  23 #include "smatch.h"
  24 #include "smatch_slist.h"
  25 #include "smatch_extra.h"
  26
  27 int check_assigned_expr_id;
  28 static int my_id;
  29 static int link_id;
  30
  31 static void undef(struct sm_state *sm, struct expression *mod_expr)
  32 {
  33         set_state(my_id, sm->name, sm->sym, &undefined);
  34 }
  35
  36 struct expression *get_assigned_expr(struct expression *expr)
  37 {
  38         struct smatch_state *state;
  39
  40         state = get_state_expr(my_id, expr);
  41         if (!state)
  42                 return NULL;
  43         return (struct expression *)state->data;
  44 }
  45
  46 struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
  47 {
  48         struct smatch_state *state;
  49
  50         state = get_state(my_id, name, sym);
  51         if (!state)
  52                 return NULL;
  53         return (struct expression *)state->data;
  54 }
  55
  56 static void match_assignment(struct expression *expr)
  57 {
  58         struct symbol *left_sym, *right_sym;
  59         char *left_name = NULL;
  60         char *right_name = NULL;
  61
  62         if (expr->op != '=')
  63                 return;
  64         if (is_fake_call(expr->right) || __in_fake_assign)
  65                 return;
  66
  67         left_name = expr_to_var_sym(expr->left, &left_sym);
  68         if (!left_name || !left_sym)
  69                 goto free;
  70         set_state(my_id, left_name, left_sym, alloc_state_expr(strip_expr(expr->right)));
  71
  72         right_name = expr_to_var_sym(expr->right, &right_sym);
  73         if (!right_name || !right_sym)
  74                 goto free;
  75
  76         store_link(link_id, right_name, right_sym, left_name, left_sym);
  77
  78 free:
  79         free_string(left_name);
  80         free_string(right_name);
  81 }
  82
  83 static void record_param_assignment(struct expression *expr, int param, char *key, char *value)
  84 {
  85         struct expression *arg, *right;
  86         struct symbol *sym;
  87         char *name;
  88         char *p;
  89         int right_param;
  90
  91         while (expr->type == EXPR_ASSIGNMENT)
  92                 expr = strip_expr(expr->right);
  93         if (!expr || expr->type != EXPR_CALL)
  94                 return;
  95
  96         p = strstr(value, "[$");
  97         if (!p)
  98                 return;
  99
 100         p += 2;
 101         right_param = strtol(p, &p, 10);
 102         if (*p != ']')
 103                 return;
 104
 105         arg = get_argument_from_call_expr(expr->args, param);
 106         right = get_argument_from_call_expr(expr->args, right_param);
 107         if (!right || !arg)
 108                 return;
 109         name = get_variable_from_key(arg, key, &sym);
 110         if (!name || !sym)
 111                 goto free;
 112
 113         if (local_debug)
 114                 sm_msg("FAKE ASSIGN: %s = %s.  sym = %p", name, expr_to_str(right), sym);
 115         set_state(my_id, name, sym, alloc_state_expr(right));
 116 free:
 117         free_string(name);
 118 }
 119
 120 void check_assigned_expr(int id)
 121 {
 122         my_id = check_assigned_expr_id = id;
 123         add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
 124         add_modification_hook(my_id, &undef);
 125         select_return_states_hook(PARAM_SET, &record_param_assignment);
 126 }
 127
 128 void check_assigned_expr_links(int id)
 129 {
 130         link_id = id;
 131         set_up_link_functions(my_id, link_id);
 132 }
 133