smatch_type_val.c

   1 /*
   2  * Copyright (C) 2013 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 /*
  19  * The plan here is to save all the possible values store to a given struct
  20  * member.
  21  *
  22  * We will load all the values in to the function_type_val table first then
  23  * run a script on that and load all the resulting values into the type_val
  24  * table.
  25  *
  26  * So in this file we want to take the union of everything assigned to the
  27  * struct member and insert it into the function_type_val at the end.
  28  *
  29  * You would think that we could use smatch_modification_hooks.c or
  30  * extra_modification_hook() here to get the information here but in the end we
  31  * need to code everything again a third time.
  32  *
  33  */
  34
  35 #include "smatch.h"
  36 #include "smatch_slist.h"
  37 #include "smatch_extra.h"
  38
  39 static int my_id;
  40
  41 struct stree_stack *fn_type_val_stack;
  42 struct stree *fn_type_val;
  43 struct stree *global_type_val;
  44
  45 static char *db_vals;
  46 static int get_vals(void *unused, int argc, char **argv, char **azColName)
  47 {
  48         db_vals = alloc_string(argv[0]);
  49         return 0;
  50 }
  51
  52 static void match_inline_start(struct expression *expr)
  53 {
  54         push_stree(&fn_type_val_stack, fn_type_val);
  55         fn_type_val = NULL;
  56 }
  57
  58 static void match_inline_end(struct expression *expr)
  59 {
  60         free_stree(&fn_type_val);
  61         fn_type_val = pop_stree(&fn_type_val_stack);
  62 }
  63
  64 int get_db_type_rl(struct expression *expr, struct range_list **rl)
  65 {
  66         char *member;
  67         struct range_list *tmp;
  68
  69         member = get_member_name(expr);
  70         if (!member)
  71                 return 0;
  72
  73         db_vals = NULL;
  74         run_sql(get_vals, NULL,
  75                 "select value from type_value where type = '%s';", member);
  76         free_string(member);
  77         if (!db_vals)
  78                 return 0;
  79         str_to_rl(&llong_ctype, db_vals, &tmp);
  80         tmp = cast_rl(get_type(expr), tmp);
  81         if (is_whole_rl(tmp))
  82                 return 0;
  83         *rl = tmp;
  84         free_string(db_vals);
  85
  86         return 1;
  87 }
  88
  89 static void add_type_val(char *member, struct range_list *rl)
  90 {
  91         struct smatch_state *old, *add, *new;
  92
  93         member = alloc_string(member);
  94         old = get_state_stree(fn_type_val, my_id, member, NULL);
  95         add = alloc_estate_rl(rl);
  96         if (old)
  97                 new = merge_estates(old, add);
  98         else
  99                 new = add;
 100         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 101 }
 102
 103 static void add_fake_type_val(char *member, struct range_list *rl, int ignore)
 104 {
 105         struct smatch_state *old, *add, *new;
 106
 107         member = alloc_string(member);
 108         old = get_state_stree(fn_type_val, my_id, member, NULL);
 109         if (old && strcmp(old->name, "min-max") == 0)
 110                 return;
 111         if (ignore && old && strcmp(old->name, "ignore") == 0)
 112                 return;
 113         add = alloc_estate_rl(rl);
 114         if (old) {
 115                 new = merge_estates(old, add);
 116         } else {
 117                 new = add;
 118                 if (ignore)
 119                         new->name = alloc_string("ignore");
 120                 else
 121                         new->name = alloc_string("min-max");
 122         }
 123         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 124 }
 125
 126 static void add_global_type_val(char *member, struct range_list *rl)
 127 {
 128         struct smatch_state *old, *add, *new;
 129
 130         member = alloc_string(member);
 131         old = get_state_stree(global_type_val, my_id, member, NULL);
 132         add = alloc_estate_rl(rl);
 133         if (old)
 134                 new = merge_estates(old, add);
 135         else
 136                 new = add;
 137         new = clone_estate_perm(new);
 138         set_state_stree_perm(&global_type_val, my_id, member, NULL, new);
 139 }
 140
 141 static int has_link_cb(void *has_link, int argc, char **argv, char **azColName)
 142 {
 143         *(int *)has_link = 1;
 144         return 0;
 145 }
 146 static int is_ignored_fake_assignment(void)
 147 {
 148         struct expression *expr;
 149         struct symbol *type;
 150         char *member_name;
 151         int has_link = 0;
 152
 153         expr = get_faked_expression();
 154         if (!expr || expr->type != EXPR_ASSIGNMENT)
 155                 return 0;
 156         if (!is_void_pointer(expr->right))
 157                 return 0;
 158         member_name = get_member_name(expr->right);
 159         if (!member_name)
 160                 return 0;
 161
 162         type = get_type(expr->left);
 163         if (!type || type->type != SYM_PTR)
 164                 return 0;
 165         type = get_real_base_type(type);
 166         if (!type || type->type != SYM_STRUCT)
 167                 return 0;
 168
 169         run_sql(has_link_cb, &has_link,
 170                 "select * from data_info where type = %d and data = '%s' and value = '%s';",
 171                 TYPE_LINK, member_name, type_to_str(type));
 172         return has_link;
 173 }
 174
 175 static void match_assign_value(struct expression *expr)
 176 {
 177         char *member, *right_member;
 178         struct range_list *rl;
 179         struct symbol *type;
 180
 181         type = get_type(expr->left);
 182         if (type && type->type == SYM_STRUCT)
 183                 return;
 184
 185         member = get_member_name(expr->left);
 186         if (!member)
 187                 return;
 188
 189         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 190         right_member = get_member_name(expr->right);
 191         if (right_member && strcmp(right_member, member) == 0)
 192                 goto free;
 193
 194         if (is_fake_call(expr->right)) {
 195                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)), is_ignored_fake_assignment());
 196                 goto free;
 197         }
 198
 199         if (expr->op != '=') {
 200                 add_type_val(member, alloc_whole_rl(get_type(expr->left)));
 201                 goto free;
 202         }
 203         get_absolute_rl(expr->right, &rl);
 204         rl = cast_rl(type, rl);
 205         add_type_val(member, rl);
 206 free:
 207         free_string(right_member);
 208         free_string(member);
 209 }
 210
 211 /*
 212  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 213  * my_struct->member.
 214  */
 215 static void match_assign_pointer(struct expression *expr)
 216 {
 217         struct expression *right;
 218         char *member;
 219         struct range_list *rl;
 220         struct symbol *type;
 221
 222         right = strip_expr(expr->right);
 223         if (right->type != EXPR_PREOP || right->op != '&')
 224                 return;
 225         right = strip_expr(right->unop);
 226
 227         member = get_member_name(right);
 228         if (!member)
 229                 return;
 230         type = get_type(right);
 231         rl = alloc_whole_rl(type);
 232         add_type_val(member, rl);
 233         free_string(member);
 234 }
 235
 236 static void match_global_assign(struct expression *expr)
 237 {
 238         char *member;
 239         struct range_list *rl;
 240
 241         member = get_member_name(expr->left);
 242         if (!member)
 243                 return;
 244         get_absolute_rl(expr->right, &rl);
 245         add_global_type_val(member, rl);
 246         free_string(member);
 247 }
 248
 249 static void unop_expr(struct expression *expr)
 250 {
 251         struct range_list *rl;
 252         char *member;
 253
 254         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 255                 return;
 256
 257         expr = strip_expr(expr->unop);
 258         member = get_member_name(expr);
 259         if (!member)
 260                 return;
 261         rl = alloc_whole_rl(get_type(expr));
 262         add_type_val(member, rl);
 263         free_string(member);
 264 }
 265
 266 static void asm_expr(struct statement *stmt)
 267 {
 268         struct expression *expr;
 269         struct range_list *rl;
 270         char *member;
 271         int state = 0;
 272
 273         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 274                 switch (state) {
 275                 case 0: /* identifier */
 276                 case 1: /* constraint */
 277                         state++;
 278                         continue;
 279                 case 2: /* expression */
 280                         state = 0;
 281                         member = get_member_name(expr);
 282                         if (!member)
 283                                 continue;
 284                         rl = alloc_whole_rl(get_type(expr));
 285                         add_type_val(member, rl);
 286                         free_string(member);
 287                         continue;
 288                 }
 289         } END_FOR_EACH_PTR(expr);
 290 }
 291
 292 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 293 {
 294         struct expression *arg;
 295         struct symbol *type;
 296         struct range_list *rl;
 297         char *member;
 298
 299         if (strcmp(key, "*$") != 0)
 300                 return;
 301
 302         while (expr->type == EXPR_ASSIGNMENT)
 303                 expr = strip_expr(expr->right);
 304         if (expr->type != EXPR_CALL)
 305                 return;
 306
 307         arg = get_argument_from_call_expr(expr->args, param);
 308         arg = strip_expr(arg);
 309         if (!arg)
 310                 return;
 311         type = get_member_type_from_key(arg, key);
 312         if (arg->type != EXPR_PREOP || arg->op != '&')
 313                 return;
 314         arg = strip_expr(arg->unop);
 315
 316         member = get_member_name(arg);
 317         if (!member)
 318                 return;
 319         call_results_to_rl(expr, type, value, &rl);
 320         add_type_val(member, rl);
 321         free_string(member);
 322 }
 323
 324 static void match_end_func_info(struct symbol *sym)
 325 {
 326         struct sm_state *sm;
 327
 328         FOR_EACH_SM(fn_type_val, sm) {
 329                 sql_insert_function_type_value(sm->name, sm->state->name);
 330         } END_FOR_EACH_SM(sm);
 331
 332         free_stree(&fn_type_val);
 333 }
 334
 335 static void match_end_file(struct symbol_list *sym_list)
 336 {
 337         struct sm_state *sm;
 338
 339         FOR_EACH_SM(global_type_val, sm) {
 340                 sql_insert_function_type_value(sm->name, sm->state->name);
 341         } END_FOR_EACH_SM(sm);
 342 }
 343
 344 void register_type_val(int id)
 345 {
 346         if (!option_info)
 347                 return;
 348
 349         my_id = id;
 350
 351         add_hook(&match_assign_value, ASSIGNMENT_HOOK);
 352         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 353         add_hook(&unop_expr, OP_HOOK);
 354         add_hook(&asm_expr, ASM_HOOK);
 355         select_return_states_hook(ADDED_VALUE, &db_param_add);
 356
 357         add_hook(&match_inline_start, INLINE_FN_START);
 358         add_hook(&match_inline_end, INLINE_FN_END);
 359
 360         add_hook(&match_end_func_info, END_FUNC_HOOK);
 361
 362         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 363         add_hook(&match_end_file, END_FILE_HOOK);
 364
 365 }