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_pointer_assign(void)
 276 {
 277         struct expression *expr;
 278         struct symbol *left_type, *right_type;
 279
 280         expr = get_faked_expression();
 281         if (!expr)
 282                 return 0;
 283         if (expr->type == EXPR_PREOP || expr->type == EXPR_POSTOP) {
 284                 if (expr->op == SPECIAL_INCREMENT || expr->op == SPECIAL_DECREMENT)
 285                         return 1;
 286         }
 287         if (expr->type != EXPR_ASSIGNMENT)
 288                 return 0;
 289         left_type = get_type(expr->left);
 290         right_type = get_type(expr->right);
 291
 292         if (!left_type || !right_type)
 293                 return 0;
 294
 295         if (left_type->type != SYM_PTR &&
 296             left_type->type != SYM_ARRAY)
 297                 return 0;
 298         if (right_type->type != SYM_PTR &&
 299             right_type->type != SYM_ARRAY)
 300                 return 0;
 301         left_type = get_real_base_type(left_type);
 302         right_type = get_real_base_type(right_type);
 303
 304         if (left_type == right_type)
 305                 return 1;
 306         return 0;
 307 }
 308
 309 static int set_param_type(void *_type_str, int argc, char **argv, char **azColName)
 310 {
 311         char **type_str = _type_str;
 312         static char type_buf[128];
 313
 314         if (*type_str) {
 315                 if (strcmp(*type_str, argv[0]) == 0)
 316                         return 0;
 317                 strncpy(type_buf, "unknown", sizeof(type_buf));
 318                 return 0;
 319         }
 320         strncpy(type_buf, argv[0], sizeof(type_buf));
 321         *type_str = type_buf;
 322
 323         return 0;
 324 }
 325
 326 static char *db_get_parameter_type(int param)
 327 {
 328         char *ret = NULL;
 329
 330         if (!cur_func_sym)
 331                 return NULL;
 332
 333         run_sql(set_param_type, &ret,
 334                 "select value from fn_data_link where "
 335                 "file = '%s' and function = '%s' and static = %d and type = %d and parameter = %d and key = '$';",
 336                 (cur_func_sym->ctype.modifiers & MOD_STATIC) ? get_base_file() : "extern",
 337                 cur_func_sym->ident->name,
 338                 !!(cur_func_sym->ctype.modifiers & MOD_STATIC),
 339                 PASSES_TYPE, param);
 340
 341         return ret;
 342 }
 343
 344 static int is_uncasted_fn_param_from_db(void)
 345 {
 346         struct expression *expr, *right;
 347         struct symbol *left_type;
 348         char left_type_name[128];
 349         int param;
 350         char *right_type_name;
 351         static struct expression *prev_expr;
 352         static int prev_ans;
 353
 354         expr = get_faked_expression();
 355
 356         if (expr == prev_expr)
 357                 return prev_ans;
 358         prev_expr = expr;
 359         prev_ans = 0;
 360
 361         if (!expr || expr->type != EXPR_ASSIGNMENT)
 362                 return 0;
 363         left_type = get_type(expr->left);
 364         if (!left_type || left_type->type != SYM_PTR)
 365                 return 0;
 366         left_type = get_real_base_type(left_type);
 367         if (!left_type || left_type->type != SYM_STRUCT)
 368                 return 0;
 369         snprintf(left_type_name, sizeof(left_type_name), "%s", type_to_str(left_type));
 370
 371         right = strip_expr(expr->right);
 372         param = get_param_num(right);
 373         if (param < 0)
 374                 return 0;
 375         right_type_name = db_get_parameter_type(param);
 376         if (!right_type_name)
 377                 return 0;
 378
 379         if (strcmp(right_type_name, left_type_name) == 0) {
 380                 prev_ans = 1;
 381                 return 1;
 382         }
 383
 384         return 0;
 385 }
 386
 387 static void match_assign_value(struct expression *expr)
 388 {
 389         char *member, *right_member;
 390         struct range_list *rl;
 391         struct symbol *type;
 392
 393         type = get_type(expr->left);
 394         if (type && type->type == SYM_STRUCT)
 395                 return;
 396
 397         member = get_member_name(expr->left);
 398         if (!member)
 399                 return;
 400
 401         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 402         right_member = get_member_name(expr->right);
 403         if (right_member && strcmp(right_member, member) == 0)
 404                 goto free;
 405
 406         if (is_fake_call(expr->right)) {
 407                 if (is_ignored_macro())
 408                         goto free;
 409                 if (is_ignored_function())
 410                         goto free;
 411                 if (is_uncasted_pointer_assign())
 412                         goto free;
 413                 if (is_uncasted_fn_param_from_db())
 414                         goto free;
 415                 if (is_container_of())
 416                         goto free;
 417                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)), is_ignored_fake_assignment());
 418                 goto free;
 419         }
 420
 421         if (expr->op == '=') {
 422                 get_absolute_rl(expr->right, &rl);
 423                 rl = cast_rl(type, rl);
 424         } else {
 425                 /*
 426                  * This is a bit cheating.  We order it so this will already be set
 427                  * by smatch_extra.c and we just look up the value.
 428                  */
 429                 get_absolute_rl(expr->left, &rl);
 430         }
 431         add_type_val(member, rl);
 432 free:
 433         free_string(right_member);
 434         free_string(member);
 435 }
 436
 437 /*
 438  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 439  * my_struct->member.
 440  */
 441 static void match_assign_pointer(struct expression *expr)
 442 {
 443         struct expression *right;
 444         char *member;
 445         struct range_list *rl;
 446         struct symbol *type;
 447
 448         right = strip_expr(expr->right);
 449         if (right->type != EXPR_PREOP || right->op != '&')
 450                 return;
 451         right = strip_expr(right->unop);
 452
 453         member = get_member_name(right);
 454         if (!member)
 455                 return;
 456         type = get_type(right);
 457         rl = alloc_whole_rl(type);
 458         add_type_val(member, rl);
 459         free_string(member);
 460 }
 461
 462 static void match_global_assign(struct expression *expr)
 463 {
 464         char *member;
 465         struct range_list *rl;
 466         struct symbol *type;
 467
 468         type = get_type(expr->left);
 469         if (type && (type->type == SYM_ARRAY || type->type == SYM_STRUCT))
 470                 return;
 471         member = get_member_name(expr->left);
 472         if (!member)
 473                 return;
 474         get_absolute_rl(expr->right, &rl);
 475         rl = cast_rl(type, rl);
 476         add_global_type_val(member, rl);
 477         free_string(member);
 478 }
 479
 480 static void unop_expr(struct expression *expr)
 481 {
 482         struct range_list *rl;
 483         char *member;
 484
 485         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 486                 return;
 487
 488         expr = strip_expr(expr->unop);
 489         member = get_member_name(expr);
 490         if (!member)
 491                 return;
 492         rl = alloc_whole_rl(get_type(expr));
 493         add_type_val(member, rl);
 494         free_string(member);
 495 }
 496
 497 static void asm_expr(struct statement *stmt)
 498 {
 499         struct expression *expr;
 500         struct range_list *rl;
 501         char *member;
 502         int state = 0;
 503
 504         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 505                 switch (state) {
 506                 case 0: /* identifier */
 507                 case 1: /* constraint */
 508                         state++;
 509                         continue;
 510                 case 2: /* expression */
 511                         state = 0;
 512                         member = get_member_name(expr);
 513                         if (!member)
 514                                 continue;
 515                         rl = alloc_whole_rl(get_type(expr));
 516                         add_type_val(member, rl);
 517                         free_string(member);
 518                         continue;
 519                 }
 520         } END_FOR_EACH_PTR(expr);
 521 }
 522
 523 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 524 {
 525         struct expression *arg;
 526         struct symbol *type;
 527         struct range_list *rl;
 528         char *member;
 529
 530         if (strcmp(key, "*$") != 0)
 531                 return;
 532
 533         while (expr->type == EXPR_ASSIGNMENT)
 534                 expr = strip_expr(expr->right);
 535         if (expr->type != EXPR_CALL)
 536                 return;
 537
 538         arg = get_argument_from_call_expr(expr->args, param);
 539         arg = strip_expr(arg);
 540         if (!arg)
 541                 return;
 542         type = get_member_type_from_key(arg, key);
 543         if (arg->type != EXPR_PREOP || arg->op != '&')
 544                 return;
 545         arg = strip_expr(arg->unop);
 546
 547         member = get_member_name(arg);
 548         if (!member)
 549                 return;
 550         call_results_to_rl(expr, type, value, &rl);
 551         add_type_val(member, rl);
 552         free_string(member);
 553 }
 554
 555 static void match_end_func_info(struct symbol *sym)
 556 {
 557         struct sm_state *sm;
 558
 559         FOR_EACH_SM(fn_type_val, sm) {
 560                 sql_insert_function_type_value(sm->name, sm->state->name);
 561         } END_FOR_EACH_SM(sm);
 562 }
 563
 564 static void clear_cache(struct symbol *sym)
 565 {
 566         memset(cached_results, 0, sizeof(cached_results));
 567 }
 568
 569 static void match_after_func(struct symbol *sym)
 570 {
 571         free_stree(&fn_type_val);
 572 }
 573
 574 static void match_end_file(struct symbol_list *sym_list)
 575 {
 576         struct sm_state *sm;
 577
 578         FOR_EACH_SM(global_type_val, sm) {
 579                 sql_insert_function_type_value(sm->name, sm->state->name);
 580         } END_FOR_EACH_SM(sm);
 581 }
 582
 583 void register_type_val(int id)
 584 {
 585         my_id = id;
 586         add_hook(&clear_cache, AFTER_FUNC_HOOK);
 587
 588         if (!option_info)
 589                 return;
 590
 591         add_hook(&match_assign_value, ASSIGNMENT_HOOK_AFTER);
 592         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 593         add_hook(&unop_expr, OP_HOOK);
 594         add_hook(&asm_expr, ASM_HOOK);
 595         select_return_states_hook(PARAM_ADD, &db_param_add);
 596         select_return_states_hook(PARAM_SET, &db_param_add);
 597
 598
 599         add_hook(&match_inline_start, INLINE_FN_START);
 600         add_hook(&match_inline_end, INLINE_FN_END);
 601
 602         add_hook(&match_end_func_info, END_FUNC_HOOK);
 603         add_hook(&match_after_func, AFTER_FUNC_HOOK);
 604
 605         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 606         add_hook(&match_end_file, END_FILE_HOOK);
 607 }