smatch_flow.c

   1 /*
   2  * sparse/smatch_flow.c
   3  *
   4  * Copyright (C) 2006,2008 Dan Carpenter.
   5  *
   6  *  Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <stdio.h>
  11 #include "token.h"
  12 #include "smatch.h"
  13
  14 int __smatch_lineno = 0;
  15
  16 static char *filename;
  17 static char *cur_func;
  18 static int line_func_start;
  19 static unsigned int path_id = 0;
  20 static unsigned int path_id_next = 1;
  21
  22 char *get_filename() {  return filename; }
  23 char *get_function() { return cur_func; }
  24 int get_lineno() { return __smatch_lineno; }
  25 int get_func_pos() { return __smatch_lineno - line_func_start; }
  26
  27 static void split_statements(struct statement *stmt);
  28 static void split_symlist(struct symbol_list *sym_list);
  29 static void split_expr_list(struct expression_list *expr_list);
  30
  31 unsigned int get_path_id()
  32 {
  33         return path_id;
  34 }
  35
  36 unsigned int __split_path_id()
  37 {
  38         int tmp = path_id;
  39
  40         path_id = path_id_next++;
  41         return tmp;
  42 }
  43
  44 void __restore_path_id(int old_id)
  45 {
  46         path_id = old_id;
  47 }
  48
  49
  50
  51 void __split_expr(struct expression *expr)
  52 {
  53         if (!expr)
  54                 return;
  55
  56         __smatch_lineno = expr->pos.line;
  57         __pass_to_client(expr, EXPR_HOOK);
  58
  59         // printf("%d Debug expr_type %d\n", get_lineno(), expr->type);
  60
  61         switch (expr->type) {
  62         case EXPR_PREOP:
  63         case EXPR_POSTOP:
  64                 if (expr->op == '*')
  65                         __pass_to_client(expr, DEREF_HOOK);
  66                 __split_expr(expr->unop);
  67                 return;
  68         case EXPR_STATEMENT:
  69                 split_statements(expr->statement);
  70                 return;
  71         case EXPR_BINOP:
  72         case EXPR_COMMA:
  73         case EXPR_COMPARE:
  74         case EXPR_LOGICAL:
  75         case EXPR_ASSIGNMENT:
  76                 if (expr->type == EXPR_ASSIGNMENT)
  77                         __pass_to_client(expr, ASSIGNMENT_HOOK);
  78                 __split_expr(expr->left);
  79                 __split_expr(expr->right);
  80                 if (expr->type == EXPR_ASSIGNMENT)
  81                         __pass_to_client(expr, ASSIGNMENT_AFTER_HOOK);
  82                 return;
  83         case EXPR_DEREF:
  84                 __pass_to_client(expr, DEREF_HOOK);
  85                 __split_expr(expr->deref);
  86                 return;
  87         case EXPR_SLICE:
  88                 __split_expr(expr->base);
  89                 return;
  90         case EXPR_CAST:
  91                 __split_expr(expr->cast_expression);
  92                 return;
  93         case EXPR_SIZEOF:
  94                 /* there isn't anything to pass a client from inside a sizeof() */
  95                 return;
  96         case EXPR_CONDITIONAL:
  97         case EXPR_SELECT:
  98                 __split_true_false_paths();
  99                 __split_whole_condition(expr->conditional);
 100                 __use_true_states();
 101                 __split_expr(expr->cond_true);
 102                 __use_false_states();
 103                 __split_expr(expr->cond_false);
 104                 __merge_true_states();
 105                 return;
 106         case EXPR_CALL:
 107                 __pass_to_client(expr, FUNCTION_CALL_HOOK);
 108                 __split_expr(expr->fn);
 109                 split_expr_list(expr->args);
 110                 __pass_to_client(expr, FUNCTION_CALL_AFTER_HOOK);
 111 #ifdef KERNEL
 112                 if (expr->fn->type == EXPR_SYMBOL &&
 113                     !strcmp(expr->fn->symbol_name->name, "panic"))
 114                         nullify_path();
 115 #endif
 116                 return;
 117         case EXPR_INITIALIZER:
 118                 split_expr_list(expr->expr_list);
 119                 return;
 120         case EXPR_IDENTIFIER:
 121                 __split_expr(expr->ident_expression);
 122                 return;
 123         case EXPR_INDEX:
 124                 __split_expr(expr->idx_expression);
 125                 return;
 126         case EXPR_POS:
 127                 __split_expr(expr->init_expr);
 128                 return;
 129         default:
 130                 return;
 131         };
 132 }
 133
 134 static int is_forever_loop(struct statement *stmt)
 135 {
 136
 137         struct expression *expr;
 138
 139         expr = stmt->iterator_pre_condition;
 140         if (!expr)
 141                 expr = stmt->iterator_post_condition;
 142         if (!expr) {
 143                 // this is a for(;;) loop...
 144                 return 1;
 145         }
 146
 147         if (expr->type == EXPR_VALUE && expr->value == 1) {
 148                 return 1;
 149         }
 150
 151         return 0;
 152 }
 153
 154 /*
 155  * Pre Loops are while and for loops.
 156  */
 157
 158 static void handle_pre_loop(struct statement *stmt)
 159 {
 160         unsigned int path_orig;
 161
 162         split_statements(stmt->iterator_pre_statement);
 163
 164         __split_true_false_paths();
 165         __push_continues();
 166         __push_breaks();
 167         if (stmt->iterator_pre_condition) {
 168                 __split_whole_condition(stmt->iterator_pre_condition);
 169         }
 170         path_orig = __split_path_id();
 171         __use_true_states();
 172
 173         split_statements(stmt->iterator_statement);
 174         split_statements(stmt->iterator_post_statement);
 175         if (is_forever_loop(stmt)) {
 176                 __pop_continues();
 177                 __pop_false_states();
 178                 nullify_path();
 179         } else {
 180                 __merge_false_states();
 181                 __merge_continues();
 182         }
 183         __merge_breaks();
 184         __restore_path_id(path_orig);
 185 }
 186
 187 /*
 188  * Post loops are do {} while();
 189  */
 190 static void handle_post_loop(struct statement *stmt)
 191 {
 192         __push_continues();
 193         __push_breaks();
 194         split_statements(stmt->iterator_statement);
 195
 196         __split_true_false_paths();
 197         __split_whole_condition(stmt->iterator_post_condition);
 198         /* It would prossibly be cleaner to make this all one function */
 199         __use_true_states();
 200         __use_false_states();
 201         __pop_true_states();
 202
 203         if (is_forever_loop(stmt)) {
 204                 __pop_continues();
 205                 nullify_path();
 206         } else {
 207                 __merge_continues();
 208         }
 209         __merge_breaks();
 210 }
 211
 212 static void split_statements(struct statement *stmt)
 213 {
 214         unsigned int path_orig;
 215
 216         if (!stmt)
 217                 return;
 218
 219         __smatch_lineno = stmt->pos.line;
 220         __pass_to_client(stmt, STMT_HOOK);
 221
 222         switch (stmt->type) {
 223         case STMT_DECLARATION:
 224                 __pass_declarations_to_client(stmt->declaration);
 225                 split_symlist(stmt->declaration);
 226                 return;
 227         case STMT_RETURN:
 228                 __pass_to_client(stmt, RETURN_HOOK);
 229                 __split_expr(stmt->ret_value);
 230                 nullify_path();
 231                 return;
 232         case STMT_EXPRESSION:
 233                 __split_expr(stmt->expression);
 234                 return;
 235         case STMT_COMPOUND: {
 236                 struct statement *s;
 237                 FOR_EACH_PTR(stmt->stmts, s) {
 238                         split_statements(s);
 239                 } END_FOR_EACH_PTR(s);
 240                 return;
 241         }
 242         case STMT_IF:
 243                 __split_true_false_paths();
 244                 __split_whole_condition(stmt->if_conditional);
 245                 path_orig = __split_path_id();
 246                 __use_true_states();
 247                 split_statements(stmt->if_true);
 248                 __split_path_id();
 249                 __use_false_states();
 250                 split_statements(stmt->if_false);
 251                 __merge_true_states();
 252                 __restore_path_id(path_orig);
 253                 return;
 254         case STMT_ITERATOR:
 255                 if (stmt->iterator_pre_condition)
 256                         handle_pre_loop(stmt);
 257                 else if (stmt->iterator_post_condition)
 258                         handle_post_loop(stmt);
 259                 else {
 260                         // these are for(;;) type loops.
 261                         handle_pre_loop(stmt);
 262                 }
 263                 return;
 264         case STMT_SWITCH:
 265                 __split_expr(stmt->switch_expression);
 266                 __save_switch_states();
 267                 __push_default();
 268                 __push_breaks();
 269                 nullify_path();
 270                 path_orig = get_path_id();
 271                 split_statements(stmt->switch_statement);
 272                 if (!__pop_default())
 273                         __merge_switches();
 274                 __pop_switches();
 275                 __merge_breaks();
 276                 __restore_path_id(path_orig);
 277                 return;
 278         case STMT_CASE:
 279                 __split_path_id();
 280                 __merge_switches();
 281                 if (!stmt->case_expression)
 282                         __set_default();
 283                 __split_expr(stmt->case_expression);
 284                 __split_expr(stmt->case_to);
 285                 split_statements(stmt->case_statement);
 286                 return;
 287         case STMT_LABEL:
 288                 if (stmt->label &&
 289                     stmt->label->type == SYM_LABEL &&
 290                     stmt->label->ident) {
 291                         __merge_gotos(stmt->label->ident->name);
 292                 }
 293                 split_statements(stmt->label_statement);
 294                 return;
 295         case STMT_GOTO:
 296                 __split_expr(stmt->goto_expression);
 297                 if (stmt->goto_label && stmt->goto_label->type == SYM_NODE) {
 298                         if (!strcmp(stmt->goto_label->ident->name, "break")) {
 299                                 __process_breaks();
 300                         } else if (!strcmp(stmt->goto_label->ident->name,
 301                                            "continue")) {
 302                                 __process_continues();
 303                         }
 304                 } else if (stmt->goto_label &&
 305                            stmt->goto_label->type == SYM_LABEL &&
 306                            stmt->goto_label->ident) {
 307                         __save_gotos(stmt->goto_label->ident->name);
 308                 }
 309                 nullify_path();
 310                 return;
 311         case STMT_NONE:
 312                 return;
 313         case STMT_ASM:
 314                 __split_expr(stmt->asm_string);
 315                 //__split_expr(stmt->asm_outputs);
 316                 //__split_expr(stmt->asm_inputs);
 317                 //__split_expr(stmt->asm_clobbers);
 318                 return;
 319         case STMT_CONTEXT:
 320                 return;
 321         case STMT_RANGE:
 322                 __split_expr(stmt->range_expression);
 323                 __split_expr(stmt->range_low);
 324                 __split_expr(stmt->range_high);
 325                 return;
 326         }
 327 }
 328
 329 static void split_expr_list(struct expression_list *expr_list)
 330 {
 331         struct expression *expr;
 332         FOR_EACH_PTR(expr_list, expr) {
 333                 __split_expr(expr);
 334         } END_FOR_EACH_PTR(expr);
 335 }
 336
 337
 338 static void split_sym(struct symbol *sym)
 339 {
 340         if (!sym)
 341                 return;
 342         if (!(sym->namespace & NS_SYMBOL))
 343                 return;
 344
 345         __pass_to_client(sym, SYM_HOOK);
 346         split_statements(sym->stmt);
 347         __split_expr(sym->array_size);
 348         split_symlist(sym->arguments);
 349         split_symlist(sym->symbol_list);
 350         split_statements(sym->inline_stmt);
 351         split_symlist(sym->inline_symbol_list);
 352         __split_expr(sym->initializer);
 353 }
 354
 355 static void split_symlist(struct symbol_list *sym_list)
 356 {
 357         struct symbol *sym;
 358
 359         FOR_EACH_PTR(sym_list, sym) {
 360                 split_sym(sym);
 361         } END_FOR_EACH_PTR(sym);
 362 }
 363
 364 static void split_functions(struct symbol_list *sym_list)
 365 {
 366         struct symbol *sym;
 367
 368         FOR_EACH_PTR(sym_list, sym) {
 369                 struct symbol *base_type;
 370                 base_type = get_base_type(sym);
 371                 if (sym->type == SYM_NODE && base_type->type == SYM_FN) {
 372                         if (base_type->stmt)
 373                                 line_func_start = base_type->stmt->pos.line;
 374                         if (sym->ident)
 375                                 cur_func = sym->ident->name;
 376                         __smatch_lineno = sym->pos.line;
 377                         __pass_to_client(sym, FUNC_DEF_HOOK);
 378                         split_statements(base_type->stmt);
 379                         __pass_to_client(sym, END_FUNC_HOOK);
 380                         cur_func = NULL;
 381                         line_func_start = 0;
 382                         clear_all_states();
 383
 384                 } else {
 385                         __pass_to_client(sym, BASE_HOOK);
 386                 }
 387         } END_FOR_EACH_PTR(sym);
 388 }
 389
 390 void smatch (int argc, char **argv)
 391 {
 392
 393         struct string_list *filelist = NULL;
 394         struct symbol_list *sym_list;
 395
 396         if (argc < 2) {
 397                 printf("Usage:  smatch <filename.c>\n");
 398                 exit(1);
 399         }
 400         sparse_initialize(argc, argv, &filelist);
 401         FOR_EACH_PTR_NOTAG(filelist, filename) {
 402                 sym_list = __sparse(filename);
 403                 split_functions(sym_list);
 404         } END_FOR_EACH_PTR_NOTAG(filename);
 405 }