smatch_helper.c

   1 /*
   2  * Copyright (C) 2006 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  * Miscellaneous helper functions.
  20  */
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include "allocate.h"
  25 #include "smatch.h"
  26
  27 #define VAR_LEN 512
  28
  29 char *alloc_string(const char *str)
  30 {
  31         char *tmp;
  32
  33         if (!str)
  34                 return NULL;
  35         tmp = malloc(strlen(str) + 1);
  36         strcpy(tmp, str);
  37         return tmp;
  38 }
  39
  40 void free_string(char *str)
  41 {
  42         free(str);
  43 }
  44
  45 void remove_parens(char *str)
  46 {
  47         char *src, *dst;
  48
  49         dst = src = str;
  50         while (*src != '\0') {
  51                 if (*src == '(' || *src == ')') {
  52                         src++;
  53                         continue;
  54                 }
  55                 *dst++ = *src++;
  56         }
  57         *dst = *src;
  58 }
  59
  60 struct smatch_state *alloc_state_num(int num)
  61 {
  62         struct smatch_state *state;
  63         static char buff[256];
  64
  65         state = __alloc_smatch_state(0);
  66         snprintf(buff, 255, "%d", num);
  67         buff[255] = '\0';
  68         state->name = alloc_string(buff);
  69         state->data = INT_PTR(num);
  70         return state;
  71 }
  72
  73 void append(char *dest, const char *data, int buff_len)
  74 {
  75         strncat(dest, data, buff_len - strlen(dest) - 1);
  76 }
  77
  78 /*
  79  * If you have "foo(a, b, 1);" then use
  80  * get_argument_from_call_expr(expr, 0) to return the expression for
  81  * a.  Yes, it does start counting from 0.
  82  */
  83 struct expression *get_argument_from_call_expr(struct expression_list *args,
  84                                                int num)
  85 {
  86         struct expression *expr;
  87         int i = 0;
  88
  89         if (!args)
  90                 return NULL;
  91
  92         FOR_EACH_PTR(args, expr) {
  93                 if (i == num)
  94                         return expr;
  95                 i++;
  96         } END_FOR_EACH_PTR(expr);
  97         return NULL;
  98 }
  99
 100 static struct expression *get_array_expr(struct expression *expr)
 101 {
 102         struct symbol *type;
 103
 104         if (expr->type != EXPR_BINOP || expr->op != '+')
 105                 return NULL;
 106
 107         type = get_type(expr->left);
 108         if (!type || type->type != SYM_ARRAY)
 109                 return NULL;
 110         return expr->left;
 111 }
 112
 113 static void __get_variable_from_expr(struct symbol **sym_ptr, char *buf,
 114                                      struct expression *expr, int len,
 115                                      int *complicated, int no_parens)
 116 {
 117         struct expression *tmp;
 118
 119         switch (expr->type) {
 120         case EXPR_DEREF:
 121                 tmp = expr->deref;
 122                 if (tmp->op == '*')
 123                         tmp = tmp->unop;
 124
 125                 __get_variable_from_expr(sym_ptr, buf, tmp, len, complicated, no_parens);
 126
 127                 tmp = expr->deref;
 128                 if (tmp->op == '*')
 129                         append(buf, "->", len);
 130                 else
 131                         append(buf, ".", len);
 132
 133                 if (expr->member && expr->member->name)
 134                         append(buf, expr->member->name, len);
 135                 else
 136                         append(buf, "unknown_member", len);
 137
 138                 return;
 139         case EXPR_SYMBOL:
 140                 if (expr->symbol_name)
 141                         append(buf, expr->symbol_name->name, len);
 142                 if (sym_ptr) {
 143                         if (*sym_ptr)
 144                                 *complicated = 1;
 145                         *sym_ptr = expr->symbol;
 146                 }
 147                 return;
 148         case EXPR_PREOP: {
 149                 const char *tmp;
 150
 151                 if (get_expression_statement(expr)) {
 152                         *complicated = 2;
 153                         return;
 154                 }
 155
 156                 if (expr->op == '(') {
 157                         if (!no_parens)
 158                                 append(buf, "(", len);
 159                 } else if (expr->op != '*' || !get_array_expr(expr->unop)) {
 160                         tmp = show_special(expr->op);
 161                         append(buf, tmp, len);
 162                 }
 163                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 164                                                  len, complicated, no_parens);
 165
 166                 if (expr->op == '(' && !no_parens)
 167                         append(buf, ")", len);
 168
 169                 if (expr->op == SPECIAL_DECREMENT ||
 170                                 expr->op == SPECIAL_INCREMENT)
 171                         *complicated = 1;
 172
 173                 return;
 174         }
 175         case EXPR_POSTOP: {
 176                 const char *tmp;
 177
 178                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 179                                                  len, complicated, no_parens);
 180                 tmp = show_special(expr->op);
 181                 append(buf, tmp, len);
 182
 183                 if (expr->op == SPECIAL_DECREMENT || expr->op == SPECIAL_INCREMENT)
 184                         *complicated = 1;
 185                 return;
 186         }
 187         case EXPR_ASSIGNMENT:
 188         case EXPR_COMPARE:
 189         case EXPR_LOGICAL:
 190         case EXPR_BINOP: {
 191                 char tmp[10];
 192                 struct expression *array_expr;
 193
 194                 *complicated = 1;
 195                 array_expr = get_array_expr(expr);
 196                 if (array_expr) {
 197                         __get_variable_from_expr(sym_ptr, buf, array_expr, len, complicated, no_parens);
 198                         append(buf, "[", len);
 199                 } else {
 200                         __get_variable_from_expr(sym_ptr, buf, expr->left, len, complicated, no_parens);
 201                         snprintf(tmp, sizeof(tmp), " %s ", show_special(expr->op));
 202                         append(buf, tmp, len);
 203                 }
 204                 __get_variable_from_expr(NULL, buf, expr->right, len, complicated, no_parens);
 205                 if (array_expr)
 206                         append(buf, "]", len);
 207                 return;
 208         }
 209         case EXPR_VALUE: {
 210                 char tmp[25];
 211
 212                 *complicated = 1;
 213                 snprintf(tmp, 25, "%lld", expr->value);
 214                 append(buf, tmp, len);
 215                 return;
 216         }
 217         case EXPR_STRING:
 218                 append(buf, "\"", len);
 219                 append(buf, expr->string->data, len);
 220                 append(buf, "\"", len);
 221                 return;
 222         case EXPR_CALL: {
 223                 struct expression *tmp;
 224                 int i;
 225
 226                 *complicated = 1;
 227                 __get_variable_from_expr(NULL, buf, expr->fn, len, complicated, no_parens);
 228                 append(buf, "(", len);
 229                 i = 0;
 230                 FOR_EACH_PTR(expr->args, tmp) {
 231                         if (i++)
 232                                 append(buf, ", ", len);
 233                         __get_variable_from_expr(NULL, buf, tmp, len, complicated, no_parens);
 234                 } END_FOR_EACH_PTR(tmp);
 235                 append(buf, ")", len);
 236                 return;
 237         }
 238         case EXPR_CAST:
 239                 __get_variable_from_expr(sym_ptr, buf,
 240                                          expr->cast_expression, len,
 241                                          complicated, no_parens);
 242                 return;
 243         case EXPR_SIZEOF: {
 244                 int size;
 245                 char tmp[25];
 246
 247                 if (expr->cast_type && get_base_type(expr->cast_type)) {
 248                         size = (get_base_type(expr->cast_type))->bit_size;
 249                         snprintf(tmp, 25, "%d", bits_to_bytes(size));
 250                         append(buf, tmp, len);
 251                 }
 252                 return;
 253         }
 254         case EXPR_IDENTIFIER:
 255                 *complicated = 1;
 256                 if (expr->expr_ident && expr->expr_ident->name)
 257                         append(buf, expr->expr_ident->name, len);
 258                 return;
 259         default:
 260                 *complicated = 1;
 261                 //printf("unknown type = %d\n", expr->type);
 262                 return;
 263         }
 264 }
 265
 266 /*
 267  * This is returns a stylized "c looking" representation of the
 268  * variable name.
 269  *
 270  * It uses the same buffer every time so you have to save the result
 271  * yourself if you want to keep it.
 272  *
 273  */
 274
 275 char *expr_to_str_sym(struct expression *expr, struct symbol **sym_ptr)
 276 {
 277         static char var_name[VAR_LEN];
 278         int complicated = 0;
 279
 280         if (sym_ptr)
 281                 *sym_ptr = NULL;
 282         var_name[0] = '\0';
 283
 284         if (!expr)
 285                 return NULL;
 286         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 287                                  &complicated, 0);
 288         if (complicated < 2)
 289                 return alloc_string(var_name);
 290         else
 291                 return NULL;
 292 }
 293
 294 char *expr_to_str(struct expression *expr)
 295 {
 296         return expr_to_str_sym(expr, NULL);
 297 }
 298
 299 /*
 300  * get_variable_from_expr_simple() only returns simple variables.
 301  * If it's a complicated variable like a->foo[x] instead of just 'a->foo'
 302  * then it returns NULL.
 303  */
 304 char *expr_to_var_sym(struct expression *expr,
 305                                     struct symbol **sym_ptr)
 306 {
 307         static char var_name[VAR_LEN];
 308         int complicated = 0;
 309
 310         if (sym_ptr)
 311                 *sym_ptr = NULL;
 312         var_name[0] = '\0';
 313
 314         if (!expr)
 315                 return NULL;
 316         expr = strip_expr(expr);
 317         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 318                                  &complicated, 1);
 319
 320         if (complicated) {
 321                 if (sym_ptr)
 322                         *sym_ptr = NULL;
 323                 return NULL;
 324         }
 325         return alloc_string(var_name);
 326 }
 327
 328 char *expr_to_var(struct expression *expr)
 329 {
 330         return expr_to_var_sym(expr, NULL);
 331 }
 332
 333 int sym_name_is(const char *name, struct expression *expr)
 334 {
 335         if (!expr)
 336                 return 0;
 337         if (expr->type != EXPR_SYMBOL)
 338                 return 0;
 339         if (!strcmp(expr->symbol_name->name, name))
 340                 return 1;
 341         return 0;
 342 }
 343
 344 int is_zero(struct expression *expr)
 345 {
 346         sval_t sval;
 347
 348         if (get_value(expr, &sval) && sval.value == 0)
 349                 return 1;
 350         return 0;
 351 }
 352
 353 int is_array(struct expression *expr)
 354 {
 355         expr = strip_expr(expr);
 356         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 357                 return 0;
 358         expr = expr->unop;
 359         if (expr->op != '+')
 360                 return 0;
 361         return 1;
 362 }
 363
 364 struct expression *get_array_name(struct expression *expr)
 365 {
 366         if (!is_array(expr))
 367                 return NULL;
 368         return strip_expr(expr->unop->left);
 369 }
 370
 371 struct expression *get_array_offset(struct expression *expr)
 372 {
 373         if (!is_array(expr))
 374                 return NULL;
 375         return expr->unop->right;
 376 }
 377
 378 const char *show_state(struct smatch_state *state)
 379 {
 380         if (!state)
 381                 return NULL;
 382         return state->name;
 383 }
 384
 385 struct statement *get_expression_statement(struct expression *expr)
 386 {
 387         /* What are those things called? if (({....; ret;})) { ...*/
 388
 389         if (expr->type != EXPR_PREOP)
 390                 return NULL;
 391         if (expr->op != '(')
 392                 return NULL;
 393         if (expr->unop->type != EXPR_STATEMENT)
 394                 return NULL;
 395         if (expr->unop->statement->type != STMT_COMPOUND)
 396                 return NULL;
 397         return expr->unop->statement;
 398 }
 399
 400 struct expression *strip_parens(struct expression *expr)
 401 {
 402         if (!expr)
 403                 return NULL;
 404
 405         if (expr->type == EXPR_PREOP) {
 406                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 407                         expr->unop->statement->type == STMT_COMPOUND)
 408                         return expr;
 409                 if (expr->op == '(')
 410                         return strip_parens(expr->unop);
 411         }
 412         return expr;
 413 }
 414
 415 struct expression *strip_expr(struct expression *expr)
 416 {
 417         if (!expr)
 418                 return NULL;
 419
 420         switch (expr->type) {
 421         case EXPR_FORCE_CAST:
 422         case EXPR_CAST:
 423                 return strip_expr(expr->cast_expression);
 424         case EXPR_PREOP:
 425                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 426                         expr->unop->statement->type == STMT_COMPOUND)
 427                         return expr;
 428                 if (expr->op == '(')
 429                         return strip_expr(expr->unop);
 430         }
 431         return expr;
 432 }
 433
 434 static void delete_state_tracker(struct tracker *t)
 435 {
 436         delete_state(t->owner, t->name, t->sym);
 437         __free_tracker(t);
 438 }
 439
 440 void scoped_state(int my_id, const char *name, struct symbol *sym)
 441 {
 442         struct tracker *t;
 443
 444         t = alloc_tracker(my_id, name, sym);
 445         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 446 }
 447
 448 int is_error_return(struct expression *expr)
 449 {
 450         struct symbol *cur_func = cur_func_sym;
 451         sval_t sval;
 452
 453         if (!expr)
 454                 return 0;
 455         if (cur_func->type != SYM_NODE)
 456                 return 0;
 457         cur_func = get_base_type(cur_func);
 458         if (cur_func->type != SYM_FN)
 459                 return 0;
 460         cur_func = get_base_type(cur_func);
 461         if (cur_func == &void_ctype)
 462                 return 0;
 463         if (!get_implied_value(expr, &sval))
 464                 return 0;
 465         if (sval.value < 0)
 466                 return 1;
 467         if (cur_func->type == SYM_PTR && sval.value == 0)
 468                 return 1;
 469         return 0;
 470 }
 471
 472 int getting_address(void)
 473 {
 474         struct expression *tmp;
 475         int i = 0;
 476         int dot_ops = 0;
 477
 478         FOR_EACH_PTR_REVERSE(big_expression_stack, tmp) {
 479                 if (!i++)
 480                         continue;
 481                 if (tmp->type == EXPR_PREOP && tmp->op == '(')
 482                         continue;
 483                 if (tmp->op == '.' && !dot_ops++)
 484                         continue;
 485                 if (tmp->op == '&')
 486                         return 1;
 487                 return 0;
 488         } END_FOR_EACH_PTR_REVERSE(tmp);
 489         return 0;
 490 }
 491
 492 char *get_member_name(struct expression *expr)
 493 {
 494         char buf[256];
 495         struct symbol *sym;
 496
 497         expr = strip_expr(expr);
 498         if (expr->type != EXPR_DEREF)
 499                 return NULL;
 500         sym = get_type(expr->deref);
 501         if (!sym)
 502                 return NULL;
 503         /* FIXME: HACK! Sparse isn't storing the names of unions...  Just take last member */
 504         if (sym->type == SYM_UNION) {
 505                 struct symbol *tmp;
 506
 507                 FOR_EACH_PTR_REVERSE(sym->symbol_list, tmp) {
 508                         if (tmp->ident) {
 509                                 const char *member_name;
 510
 511                                 if (expr->member)
 512                                         member_name = expr->member->name;
 513                                 else
 514                                         member_name = "unknown_member";
 515                                 snprintf(buf, sizeof(buf), "(union hack %s)->%s", tmp->ident->name, member_name);
 516                                 return alloc_string(buf);
 517                         }
 518                 } END_FOR_EACH_PTR_REVERSE(tmp);
 519                 return NULL;
 520         }
 521         if (!sym->ident || !expr->member)
 522                 return NULL;
 523         snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, expr->member->name);
 524         return alloc_string(buf);
 525 }
 526
 527 int cmp_pos(struct position pos1, struct position pos2)
 528 {
 529         /* the stream position is ... */
 530         if (pos1.stream > pos2.stream)
 531                 return -1;
 532         if (pos1.stream < pos2.stream)
 533                 return 1;
 534
 535         if (pos1.line < pos2.line)
 536                 return -1;
 537         if (pos1.line > pos2.line)
 538                 return 1;
 539
 540         if (pos1.pos < pos2.pos)
 541                 return -1;
 542         if (pos1.pos > pos2.pos)
 543                 return 1;
 544
 545         return 0;
 546 }
 547
 548 int positions_eq(struct position pos1, struct position pos2)
 549 {
 550         if (pos1.line != pos2.line)
 551                 return 0;
 552         if (pos1.pos != pos2.pos)
 553                 return 0;
 554         if (pos1.stream != pos2.stream)
 555                 return 0;
 556         return 1;
 557 }
 558
 559 struct statement *get_current_statement(void)
 560 {
 561         struct statement *prev, *tmp;
 562
 563         prev = last_ptr_list((struct ptr_list *)big_statement_stack);
 564
 565         if (!prev || !get_macro_name(prev->pos))
 566                 return prev;
 567
 568         FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
 569                 if (positions_eq(tmp->pos, prev->pos))
 570                         continue;
 571                 if (prev->pos.line > tmp->pos.line)
 572                         return prev;
 573                 return tmp;
 574         } END_FOR_EACH_PTR_REVERSE(tmp);
 575         return prev;
 576 }
 577
 578 int get_param_num_from_sym(struct symbol *sym)
 579 {
 580         struct symbol *tmp;
 581         int i;
 582
 583         if (!cur_func_sym)
 584                 return -1;
 585
 586         i = 0;
 587         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, tmp) {
 588                 if (tmp == sym)
 589                         return i;
 590                 i++;
 591         } END_FOR_EACH_PTR(tmp);
 592         return -1;
 593 }
 594
 595 int get_param_num(struct expression *expr)
 596 {
 597         struct symbol *sym;
 598         char *name;
 599
 600         if (!cur_func_sym)
 601                 return -1;
 602         name = expr_to_var_sym(expr, &sym);
 603         free_string(name);
 604         if (!sym)
 605                 return -1;
 606         return get_param_num_from_sym(sym);
 607 }
 608
 609 int ms_since(struct timeval *start)
 610 {
 611         struct timeval end;
 612         double diff;
 613
 614         gettimeofday(&end, NULL);
 615         diff = (end.tv_sec - start->tv_sec) * 1000.0;
 616         diff += (end.tv_usec - start->tv_usec) / 1000.0;
 617         return (int)diff;
 618 }
 619