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 sm_state *get_assigned_sm(struct expression *expr)
  51 {
  52         return get_sm_state_expr(my_id, expr);
  53 }
  54
  55 struct expression *get_assigned_expr_recurse(struct expression *expr)
  56 {
  57         struct expression *ret;
  58         int cnt = 0;
  59
  60         ret = NULL;
  61         while ((expr = get_assigned_expr(expr))) {
  62                 ret = expr;
  63                 if (cnt++ > 4)
  64                         break;
  65         }
  66
  67         return ret;
  68 }
  69
  70 struct expression *get_assigned_expr_name_sym(const char *name, struct symbol *sym)
  71 {
  72         struct smatch_state *state;
  73
  74         state = __get_state(my_id, name, sym);
  75         if (!state)
  76                 return NULL;
  77         return (struct expression *)state->data;
  78 }
  79
  80 struct expression *get_assigned_expr_name_sym_recurse(const char *name, struct symbol *sym)
  81 {
  82         struct expression *expr, *recurse;
  83
  84         expr = get_assigned_expr_name_sym(name, sym);
  85         if (!expr)
  86                 return NULL;
  87         recurse = get_assigned_expr_recurse(expr);
  88         if (recurse)
  89                 return recurse;
  90         return expr;
  91 }
  92
  93 static void match_assignment(struct expression *expr)
  94 {
  95         static struct expression *ignored_expr, *right;
  96         struct symbol *left_sym, *right_sym;
  97         struct smatch_state *state;
  98         char *left_name = NULL;
  99         char *right_name = NULL;
 100
 101         if (!cur_func_sym)
 102                 return;
 103
 104         if (__in_buf_clear)
 105                 return;
 106
 107         if (expr->op != '=')
 108                 return;
 109         if (is_fake_call(expr->right))
 110                 return;
 111         if (is_fake_var_assign(expr))
 112                 return;
 113         if (__in_fake_struct_assign) {
 114                 struct range_list *rl;
 115
 116                 if (!get_implied_rl(expr->right, &rl))
 117                         return;
 118                 if (is_whole_rl(rl))
 119                         return;
 120         }
 121
 122         if (expr->left == ignored_expr)
 123                 return;
 124         ignored_expr = NULL;
 125         if (__in_fake_parameter_assign)
 126                 ignored_expr = expr->left;
 127
 128         left_name = expr_to_var_sym(expr->left, &left_sym);
 129         if (!left_name || !left_sym)
 130                 goto free;
 131
 132         right = expr->right;
 133         if (right->type == EXPR_ASSIGNMENT && right->op == '=')
 134                 right = right->left;
 135
 136         right = strip__builtin_choose_expr(right);
 137         right = strip_Generic(right);
 138
 139         state = alloc_state_expr(strip_expr(right));
 140         if (!state)
 141                 goto free;
 142
 143         skip_mod = expr;
 144         if (get_unfaked_call())
 145                 skip_mod = get_unfaked_call();
 146         set_state(my_id, left_name, left_sym, state);
 147
 148         right_name = expr_to_var_sym(right, &right_sym);
 149         if (!right_name || !right_sym)
 150                 goto free;
 151
 152         store_link(link_id, right_name, right_sym, left_name, left_sym);
 153
 154 free:
 155         free_string(left_name);
 156         free_string(right_name);
 157 }
 158
 159 static void record_param_assignment(struct expression *expr, int param, char *key, char *value)
 160 {
 161         struct expression *arg, *right;
 162         struct symbol *sym;
 163         char *name;
 164         char *p;
 165         int right_param;
 166
 167         while (expr->type == EXPR_ASSIGNMENT)
 168                 expr = strip_expr(expr->right);
 169         if (!expr || expr->type != EXPR_CALL)
 170                 return;
 171
 172         p = strstr(value, "[$");
 173         if (!p)
 174                 return;
 175
 176         p += 2;
 177         right_param = strtol(p, &p, 10);
 178         if (*p != ']')
 179                 return;
 180
 181         arg = get_argument_from_call_expr(expr->args, param);
 182         right = get_argument_from_call_expr(expr->args, right_param);
 183         if (!right || !arg)
 184                 return;
 185         name = get_variable_from_key(arg, key, &sym);
 186         if (!name || !sym)
 187                 goto free;
 188
 189         skip_mod = expr;
 190         set_state(my_id, name, sym, alloc_state_expr(right));
 191 free:
 192         free_string(name);
 193 }
 194
 195 void register_assigned_expr(int id)
 196 {
 197         my_id = check_assigned_expr_id = id;
 198         add_function_data((unsigned long *)&skip_mod);
 199         set_dynamic_states(check_assigned_expr_id);
 200         add_hook(&match_assignment, ASSIGNMENT_HOOK_AFTER);
 201         add_modification_hook_late(my_id, &undef);
 202         select_return_states_hook(PARAM_SET, &record_param_assignment);
 203 }
 204
 205 void register_assigned_expr_links(int id)
 206 {
 207         link_id = id;
 208         set_dynamic_states(link_id);
 209         db_ignore_states(link_id);
 210         set_up_link_functions(my_id, link_id);
 211 }
 212