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 int get_vals(void *_db_vals, int argc, char **argv, char **azColName)
  46 {
  47         char **db_vals = _db_vals;
  48
  49         *db_vals = alloc_string(argv[0]);
  50         return 0;
  51 }
  52
  53 static void match_inline_start(struct expression *expr)
  54 {
  55         push_stree(&fn_type_val_stack, fn_type_val);
  56         fn_type_val = NULL;
  57 }
  58
  59 static void match_inline_end(struct expression *expr)
  60 {
  61         free_stree(&fn_type_val);
  62         fn_type_val = pop_stree(&fn_type_val_stack);
  63 }
  64
  65 struct expr_rl {
  66         struct expression *expr;
  67         struct range_list *rl;
  68 };
  69 static struct expr_rl cached_results[10];
  70 static int res_idx;
  71
  72 static int get_cached(struct expression *expr, struct range_list **rl, int *ret)
  73 {
  74         int i;
  75
  76         *ret = 0;
  77
  78         for (i = 0; i < ARRAY_SIZE(cached_results); i++) {
  79                 if (expr == cached_results[i].expr) {
  80                         if (cached_results[i].rl) {
  81                                 *rl = clone_rl(cached_results[i].rl);
  82                                 *ret = 1;
  83                         }
  84                         return 1;
  85                 }
  86         }
  87
  88         return 0;
  89 }
  90
  91 int get_db_type_rl(struct expression *expr, struct range_list **rl)
  92 {
  93         char *db_vals = NULL;
  94         char *member;
  95         struct range_list *tmp;
  96         struct symbol *type;
  97         int ret;
  98
  99         if (get_cached(expr, rl, &ret))
 100                 return ret;
 101
 102         member = get_member_name(expr);
 103         if (!member)
 104                 return 0;
 105
 106         res_idx = (res_idx + 1) % ARRAY_SIZE(cached_results);
 107         cached_results[res_idx].expr = expr;
 108         cached_results[res_idx].rl = NULL;
 109
 110         run_sql(get_vals, &db_vals,
 111                 "select value from type_value where type = '%s';", member);
 112         free_string(member);
 113         if (!db_vals)
 114                 return 0;
 115         type = get_type(expr);
 116         str_to_rl(type, db_vals, &tmp);
 117         free_string(db_vals);
 118         if (is_whole_rl(tmp))
 119                 return 0;
 120
 121         *rl = tmp;
 122         cached_results[res_idx].rl = clone_rl(tmp);
 123
 124         return 1;
 125 }
 126
 127 static void add_type_val(char *member, struct range_list *rl)
 128 {
 129         struct smatch_state *old, *add, *new;
 130
 131         member = alloc_string(member);
 132         old = get_state_stree(fn_type_val, my_id, member, NULL);
 133         add = alloc_estate_rl(rl);
 134         if (old)
 135                 new = merge_estates(old, add);
 136         else
 137                 new = add;
 138         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 139 }
 140
 141 static void add_fake_type_val(char *member, struct range_list *rl, int ignore)
 142 {
 143         struct smatch_state *old, *add, *new;
 144
 145         member = alloc_string(member);
 146         old = get_state_stree(fn_type_val, my_id, member, NULL);
 147         if (old && strcmp(old->name, "min-max") == 0)
 148                 return;
 149         if (ignore && old && strcmp(old->name, "ignore") == 0)
 150                 return;
 151         add = alloc_estate_rl(rl);
 152         if (old) {
 153                 new = merge_estates(old, add);
 154         } else {
 155                 new = add;
 156                 if (ignore)
 157                         new->name = alloc_string("ignore");
 158                 else
 159                         new->name = alloc_string("min-max");
 160         }
 161         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 162 }
 163
 164 static void add_global_type_val(char *member, struct range_list *rl)
 165 {
 166         struct smatch_state *old, *add, *new;
 167
 168         member = alloc_string(member);
 169         old = get_state_stree(global_type_val, my_id, member, NULL);
 170         add = alloc_estate_rl(rl);
 171         if (old)
 172                 new = merge_estates(old, add);
 173         else
 174                 new = add;
 175         new = clone_estate_perm(new);
 176         set_state_stree_perm(&global_type_val, my_id, member, NULL, new);
 177 }
 178
 179 static int has_link_cb(void *has_link, int argc, char **argv, char **azColName)
 180 {
 181         *(int *)has_link = 1;
 182         return 0;
 183 }
 184
 185 static int is_ignored_fake_assignment(void)
 186 {
 187         struct expression *expr;
 188         struct symbol *type;
 189         char *member_name;
 190         int has_link = 0;
 191
 192         expr = get_faked_expression();
 193         if (!expr || expr->type != EXPR_ASSIGNMENT)
 194                 return 0;
 195         if (!is_void_pointer(expr->right))
 196                 return 0;
 197         member_name = get_member_name(expr->right);
 198         if (!member_name)
 199                 return 0;
 200
 201         type = get_type(expr->left);
 202         if (!type || type->type != SYM_PTR)
 203                 return 0;
 204         type = get_real_base_type(type);
 205         if (!type || type->type != SYM_STRUCT)
 206                 return 0;
 207
 208         run_sql(has_link_cb, &has_link,
 209                 "select * from data_info where type = %d and data = '%s' and value = '%s';",
 210                 TYPE_LINK, member_name, type_to_str(type));
 211         return has_link;
 212 }
 213
 214 static int is_container_of(void)
 215 {
 216         /* We already check the macro name in is_ignored_macro() */
 217         struct expression *expr;
 218         int offset;
 219
 220         expr = get_faked_expression();
 221         if (!expr || expr->type != EXPR_ASSIGNMENT)
 222                 return 0;
 223
 224         offset = get_offset_from_container_of(expr->right);
 225         if (offset < 0)
 226                 return 0;
 227         return 1;
 228 }
 229
 230 static int is_ignored_macro(void)
 231 {
 232         struct expression *expr;
 233         char *name;
 234
 235         expr = get_faked_expression();
 236         if (!expr || expr->type != EXPR_ASSIGNMENT)
 237                 return 0;
 238         name = get_macro_name(expr->right->pos);
 239         if (!name)
 240                 return 0;
 241         if (strcmp(name, "container_of") == 0)
 242                 return 1;
 243         if (strcmp(name, "rb_entry") == 0)
 244                 return 1;
 245         if (strcmp(name, "list_entry") == 0)
 246                 return 1;
 247         if (strcmp(name, "list_first_entry") == 0)
 248                 return 1;
 249         if (strcmp(name, "hlist_entry") == 0)
 250                 return 1;
 251         if (strstr(name, "for_each"))
 252                 return 1;
 253         return 0;
 254 }
 255
 256 static int is_ignored_function(void)
 257 {
 258         struct expression *expr;
 259
 260         expr = get_faked_expression();
 261         if (!expr || expr->type != EXPR_ASSIGNMENT)
 262                 return 0;
 263         expr = strip_expr(expr->right);
 264         if (!expr || expr->type != EXPR_CALL || expr->fn->type != EXPR_SYMBOL)
 265                 return 0;
 266
 267         if (sym_name_is("kmalloc", expr->fn))
 268                 return 1;
 269         if (sym_name_is("netdev_priv", expr->fn))
 270                 return 1;
 271
 272         return 0;
 273 }
 274
 275 static int is_uncasted_function(void)
 276 {
 277         struct expression *expr;
 278         struct symbol *left_type, *right_type;
 279
 280         expr = get_faked_expression();
 281         if (!expr || expr->type != EXPR_ASSIGNMENT)
 282                 return 0;
 283         if (expr->right->type != EXPR_CALL)
 284                 return 0;
 285         left_type = get_type(expr->left);
 286         right_type = get_type(expr->right);
 287
 288         if (!left_type || !right_type)
 289                 return 0;
 290         if (left_type->type != SYM_PTR || right_type->type != SYM_PTR)
 291                 return 0;
 292         left_type = get_real_base_type(left_type);
 293         right_type = get_real_base_type(right_type);
 294
 295         if (left_type == right_type)
 296                 return 1;
 297         return 0;
 298 }
 299
 300 static int set_param_type(void *_type_str, int argc, char **argv, char **azColName)
 301 {
 302         char **type_str = _type_str;
 303         static char type_buf[128];
 304
 305         if (*type_str) {
 306                 if (strcmp(*type_str, argv[0]) == 0)
 307                         return 0;
 308                 strncpy(type_buf, "unknown", sizeof(type_buf));
 309                 return 0;
 310         }
 311         strncpy(type_buf, argv[0], sizeof(type_buf));
 312         *type_str = type_buf;
 313
 314         return 0;
 315 }
 316
 317 static char *db_get_parameter_type(int param)
 318 {
 319         char *ret = NULL;
 320
 321         if (!cur_func_sym)
 322                 return NULL;
 323
 324         run_sql(set_param_type, &ret,
 325                 "select value from fn_data_link where "
 326                 "file = '%s' and function = '%s' and static = %d and type = %d and parameter = %d and key = '$';",
 327                 (cur_func_sym->ctype.modifiers & MOD_STATIC) ? get_base_file() : "extern",
 328                 cur_func_sym->ident->name,
 329                 !!(cur_func_sym->ctype.modifiers & MOD_STATIC),
 330                 PASSES_TYPE, param);
 331
 332         return ret;
 333 }
 334
 335 static int is_uncasted_fn_param_from_db(void)
 336 {
 337         struct expression *expr, *right;
 338         struct symbol *left_type;
 339         char left_type_name[128];
 340         int param;
 341         char *right_type_name;
 342         static struct expression *prev_expr;
 343         static int prev_ans;
 344
 345         expr = get_faked_expression();
 346
 347         if (expr == prev_expr)
 348                 return prev_ans;
 349         prev_expr = expr;
 350         prev_ans = 0;
 351
 352         if (!expr || expr->type != EXPR_ASSIGNMENT)
 353                 return 0;
 354         left_type = get_type(expr->left);
 355         if (!left_type || left_type->type != SYM_PTR)
 356                 return 0;
 357         left_type = get_real_base_type(left_type);
 358         if (!left_type || left_type->type != SYM_STRUCT)
 359                 return 0;
 360         snprintf(left_type_name, sizeof(left_type_name), "%s", type_to_str(left_type));
 361
 362         right = strip_expr(expr->right);
 363         param = get_param_num(right);
 364         if (param < 0)
 365                 return 0;
 366         right_type_name = db_get_parameter_type(param);
 367         if (!right_type_name)
 368                 return 0;
 369
 370         if (strcmp(right_type_name, left_type_name) == 0) {
 371                 prev_ans = 1;
 372                 return 1;
 373         }
 374
 375         return 0;
 376 }
 377
 378 static void match_assign_value(struct expression *expr)
 379 {
 380         char *member, *right_member;
 381         struct range_list *rl;
 382         struct symbol *type;
 383
 384         type = get_type(expr->left);
 385         if (type && type->type == SYM_STRUCT)
 386                 return;
 387
 388         member = get_member_name(expr->left);
 389         if (!member)
 390                 return;
 391
 392         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 393         right_member = get_member_name(expr->right);
 394         if (right_member && strcmp(right_member, member) == 0)
 395                 goto free;
 396
 397         if (is_fake_call(expr->right)) {
 398                 if (is_ignored_macro())
 399                         goto free;
 400                 if (is_ignored_function())
 401                         goto free;
 402                 if (is_uncasted_function())
 403                         goto free;
 404                 if (is_uncasted_fn_param_from_db())
 405                         goto free;
 406                 if (is_container_of())
 407                         goto free;
 408                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)), is_ignored_fake_assignment());
 409                 goto free;
 410         }
 411
 412         if (expr->op == '=') {
 413                 get_absolute_rl(expr->right, &rl);
 414                 rl = cast_rl(type, rl);
 415         } else {
 416                 /*
 417                  * This is a bit cheating.  We order it so this will already be set
 418                  * by smatch_extra.c and we just look up the value.
 419                  */
 420                 get_absolute_rl(expr->left, &rl);
 421         }
 422         add_type_val(member, rl);
 423 free:
 424         free_string(right_member);
 425         free_string(member);
 426 }
 427
 428 /*
 429  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 430  * my_struct->member.
 431  */
 432 static void match_assign_pointer(struct expression *expr)
 433 {
 434         struct expression *right;
 435         char *member;
 436         struct range_list *rl;
 437         struct symbol *type;
 438
 439         right = strip_expr(expr->right);
 440         if (right->type != EXPR_PREOP || right->op != '&')
 441                 return;
 442         right = strip_expr(right->unop);
 443
 444         member = get_member_name(right);
 445         if (!member)
 446                 return;
 447         type = get_type(right);
 448         rl = alloc_whole_rl(type);
 449         add_type_val(member, rl);
 450         free_string(member);
 451 }
 452
 453 static void match_global_assign(struct expression *expr)
 454 {
 455         char *member;
 456         struct range_list *rl;
 457         struct symbol *type;
 458
 459         type = get_type(expr->left);
 460         if (type && (type->type == SYM_ARRAY || type->type == SYM_STRUCT))
 461                 return;
 462         member = get_member_name(expr->left);
 463         if (!member)
 464                 return;
 465         get_absolute_rl(expr->right, &rl);
 466         rl = cast_rl(type, rl);
 467         add_global_type_val(member, rl);
 468         free_string(member);
 469 }
 470
 471 static void unop_expr(struct expression *expr)
 472 {
 473         struct range_list *rl;
 474         char *member;
 475
 476         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 477                 return;
 478
 479         expr = strip_expr(expr->unop);
 480         member = get_member_name(expr);
 481         if (!member)
 482                 return;
 483         rl = alloc_whole_rl(get_type(expr));
 484         add_type_val(member, rl);
 485         free_string(member);
 486 }
 487
 488 static void asm_expr(struct statement *stmt)
 489 {
 490         struct expression *expr;
 491         struct range_list *rl;
 492         char *member;
 493         int state = 0;
 494
 495         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 496                 switch (state) {
 497                 case 0: /* identifier */
 498                 case 1: /* constraint */
 499                         state++;
 500                         continue;
 501                 case 2: /* expression */
 502                         state = 0;
 503                         member = get_member_name(expr);
 504                         if (!member)
 505                                 continue;
 506                         rl = alloc_whole_rl(get_type(expr));
 507                         add_type_val(member, rl);
 508                         free_string(member);
 509                         continue;
 510                 }
 511         } END_FOR_EACH_PTR(expr);
 512 }
 513
 514 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 515 {
 516         struct expression *arg;
 517         struct symbol *type;
 518         struct range_list *rl;
 519         char *member;
 520
 521         if (strcmp(key, "*$") != 0)
 522                 return;
 523
 524         while (expr->type == EXPR_ASSIGNMENT)
 525                 expr = strip_expr(expr->right);
 526         if (expr->type != EXPR_CALL)
 527                 return;
 528
 529         arg = get_argument_from_call_expr(expr->args, param);
 530         arg = strip_expr(arg);
 531         if (!arg)
 532                 return;
 533         type = get_member_type_from_key(arg, key);
 534         if (arg->type != EXPR_PREOP || arg->op != '&')
 535                 return;
 536         arg = strip_expr(arg->unop);
 537
 538         member = get_member_name(arg);
 539         if (!member)
 540                 return;
 541         call_results_to_rl(expr, type, value, &rl);
 542         add_type_val(member, rl);
 543         free_string(member);
 544 }
 545
 546 static void match_end_func_info(struct symbol *sym)
 547 {
 548         struct sm_state *sm;
 549
 550         FOR_EACH_SM(fn_type_val, sm) {
 551                 sql_insert_function_type_value(sm->name, sm->state->name);
 552         } END_FOR_EACH_SM(sm);
 553 }
 554
 555 static void clear_cache(struct symbol *sym)
 556 {
 557         memset(cached_results, 0, sizeof(cached_results));
 558 }
 559
 560 static void match_after_func(struct symbol *sym)
 561 {
 562         free_stree(&fn_type_val);
 563 }
 564
 565 static void match_end_file(struct symbol_list *sym_list)
 566 {
 567         struct sm_state *sm;
 568
 569         FOR_EACH_SM(global_type_val, sm) {
 570                 sql_insert_function_type_value(sm->name, sm->state->name);
 571         } END_FOR_EACH_SM(sm);
 572 }
 573
 574 void register_type_val(int id)
 575 {
 576         my_id = id;
 577         add_hook(&clear_cache, AFTER_FUNC_HOOK);
 578
 579         if (!option_info)
 580                 return;
 581
 582         add_hook(&match_assign_value, ASSIGNMENT_HOOK_AFTER);
 583         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 584         add_hook(&unop_expr, OP_HOOK);
 585         add_hook(&asm_expr, ASM_HOOK);
 586         select_return_states_hook(PARAM_ADD, &db_param_add);
 587         select_return_states_hook(PARAM_SET, &db_param_add);
 588
 589
 590         add_hook(&match_inline_start, INLINE_FN_START);
 591         add_hook(&match_inline_end, INLINE_FN_END);
 592
 593         add_hook(&match_end_func_info, END_FUNC_HOOK);
 594         add_hook(&match_after_func, AFTER_FUNC_HOOK);
 595
 596         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 597         add_hook(&match_end_file, END_FILE_HOOK);
 598 }