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