smatch_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 struct expression *skip_mod;
  32
  33 static void undef(struct sm_state *sm, struct expression *mod_expr)
  34 {
  35         if (mod_expr == skip_mod)
  36                 return;
  37         set_state(my_id, sm->name, sm->sym, &undefined);
  38 }
  39
  40 struct expression *get_assigned_expr(struct expression *expr)
  41 {
  42         struct smatch_state *state;
  43
  44         state = get_state_expr(my_id, expr);
  45         if (!state)
  46                 return NULL;
  47         return (struct expression *)state->data;
  48 }
  49
  50 struct expression *get_assigned_expr_recurse(struct expression *expr)
  51 {
  52         struct expression *ret;
  53         int cnt = 0;
  54
  55         ret = NULL;
  56         while ((expr = get_assigned_expr(expr))) {
  57                 ret = expr;
  58                 if (cnt++ > 4)
  59                         break;
  60         }
  61
  62         return ret;
  63 }
  64
  65 struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
  66 {
  67         struct smatch_state *state;
  68
  69         state = __get_state(my_id, name, sym);
  70         if (!state)
  71                 return NULL;
  72         return (struct expression *)state->data;
  73 }
  74
  75 struct expression *get_assigned_expr_name_sym_recurse(const char *name, struct symbol *sym)
  76 {
  77         struct expression *expr, *recurse;
  78         struct smatch_state *state;
  79
  80         expr = get_assigned_expr_name_sym(name, sym);
  81         if (!expr)
  82                 return NULL;
  83         recurse = get_assigned_expr_recurse(expr);
  84         if (recurse)
  85                 return recurse;
  86         return expr;
  87 }
  88
  89 static void match_assignment(struct expression *expr)
  90 {
  91         static struct expression *ignored_expr, *right;
  92         struct symbol *left_sym, *right_sym;
  93         char *left_name = NULL;
  94         char *right_name = NULL;
  95
  96         if (expr->op != '=')
  97                 return;
  98         if (is_fake_call(expr->right))
  99                 return;
 100         if (__in_fake_struct_assign) {
 101                 struct range_list *rl;
 102
 103                 if (!get_implied_rl(expr->right, &rl))
 104                         return;
 105                 if (is_whole_rl(rl))
 106                         return;
 107         }
 108
 109         if (expr->left == ignored_expr)
 110                 return;
 111         ignored_expr = NULL;
 112         if (__in_fake_parameter_assign)
 113                 ignored_expr = expr->left;
 114
 115         left_name = expr_to_var_sym(expr->left, &left_sym);
 116         if (!left_name || !left_sym)
 117                 goto free;
 118
 119         right = expr->right;
 120         if (right->type == EXPR_ASSIGNMENT && right->op == '=')
 121                 right = right->left;
 122
 123         set_state(my_id, left_name, left_sym, alloc_state_expr(strip_expr(right)));
 124
 125         right_name = expr_to_var_sym(right, &right_sym);
 126         if (!right_name || !right_sym)
 127                 goto free;
 128
 129         store_link(link_id, right_name, right_sym, left_name, left_sym);
 130
 131 free:
 132         free_string(left_name);
 133         free_string(right_name);
 134 }
 135
 136 static void record_param_assignment(struct expression *expr, int param, char *key, char *value)
 137 {
 138         struct expression *arg, *right;
 139         struct symbol *sym;
 140         char *name;
 141         char *p;
 142         int right_param;
 143
 144         while (expr->type == EXPR_ASSIGNMENT)
 145                 expr = strip_expr(expr->right);
 146         if (!expr || expr->type != EXPR_CALL)
 147                 return;
 148
 149         p = strstr(value, "[$");
 150         if (!p)
 151                 return;
 152
 153         p += 2;
 154         right_param = strtol(p, &p, 10);
 155         if (*p != ']')
 156                 return;
 157
 158         arg = get_argument_from_call_expr(expr->args, param);
 159         right = get_argument_from_call_expr(expr->args, right_param);
 160         if (!right || !arg)
 161                 return;
 162         name = get_variable_from_key(arg, key, &sym);
 163         if (!name || !sym)
 164                 goto free;
 165
 166         skip_mod = expr;
 167         set_state(my_id, name, sym, alloc_state_expr(right));
 168 free:
 169         free_string(name);
 170 }
 171
 172 void register_assigned_expr(int id)
 173 {
 174         my_id = check_assigned_expr_id = id;
 175         set_dynamic_states(check_assigned_expr_id);
 176         add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
 177         add_modification_hook(my_id, &undef);
 178         select_return_states_hook(PARAM_SET, &record_param_assignment);
 179 }
 180
 181 void register_assigned_expr_links(int id)
 182 {
 183         link_id = id;
 184         set_dynamic_states(link_id);
 185         db_ignore_states(link_id);
 186         set_up_link_functions(my_id, link_id);
 187 }
 188