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 char *db_vals;
  46 static int get_vals(void *unused, int argc, char **argv, char **azColName)
  47 {
  48         db_vals = alloc_string(argv[0]);
  49         return 0;
  50 }
  51
  52 static void match_inline_start(struct expression *expr)
  53 {
  54         push_stree(&fn_type_val_stack, fn_type_val);
  55         fn_type_val = NULL;
  56 }
  57
  58 static void match_inline_end(struct expression *expr)
  59 {
  60         free_stree(&fn_type_val);
  61         fn_type_val = pop_stree(&fn_type_val_stack);
  62 }
  63
  64 int get_db_type_rl(struct expression *expr, struct range_list **rl)
  65 {
  66         char *member;
  67         struct range_list *tmp;
  68
  69         member = get_member_name(expr);
  70         if (!member)
  71                 return 0;
  72
  73         db_vals = NULL;
  74         run_sql(get_vals, NULL,
  75                 "select value from type_value where type = '%s';", member);
  76         free_string(member);
  77         if (!db_vals)
  78                 return 0;
  79         str_to_rl(&llong_ctype, db_vals, &tmp);
  80         tmp = cast_rl(get_type(expr), tmp);
  81         if (is_whole_rl(tmp))
  82                 return 0;
  83         *rl = tmp;
  84         free_string(db_vals);
  85
  86         return 1;
  87 }
  88
  89 static void add_type_val(char *member, struct range_list *rl)
  90 {
  91         struct smatch_state *old, *add, *new;
  92
  93         member = alloc_string(member);
  94         old = get_state_stree(fn_type_val, my_id, member, NULL);
  95         add = alloc_estate_rl(rl);
  96         if (old)
  97                 new = merge_estates(old, add);
  98         else
  99                 new = add;
 100         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 101 }
 102
 103 static void add_fake_type_val(char *member, struct range_list *rl, int ignore)
 104 {
 105         struct smatch_state *old, *add, *new;
 106
 107         member = alloc_string(member);
 108         old = get_state_stree(fn_type_val, my_id, member, NULL);
 109         if (old && strcmp(old->name, "min-max") == 0)
 110                 return;
 111         if (ignore && old && strcmp(old->name, "ignore") == 0)
 112                 return;
 113         add = alloc_estate_rl(rl);
 114         if (old) {
 115                 new = merge_estates(old, add);
 116         } else {
 117                 new = add;
 118                 if (ignore)
 119                         new->name = alloc_string("ignore");
 120                 else
 121                         new->name = alloc_string("min-max");
 122         }
 123         set_state_stree(&fn_type_val, my_id, member, NULL, new);
 124 }
 125
 126 static void add_global_type_val(char *member, struct range_list *rl)
 127 {
 128         struct smatch_state *old, *add, *new;
 129
 130         member = alloc_string(member);
 131         old = get_state_stree(global_type_val, my_id, member, NULL);
 132         add = alloc_estate_rl(rl);
 133         if (old)
 134                 new = merge_estates(old, add);
 135         else
 136                 new = add;
 137         new = clone_estate_perm(new);
 138         set_state_stree_perm(&global_type_val, my_id, member, NULL, new);
 139 }
 140
 141 static int has_link_cb(void *has_link, int argc, char **argv, char **azColName)
 142 {
 143         *(int *)has_link = 1;
 144         return 0;
 145 }
 146
 147 static int is_ignored_fake_assignment(void)
 148 {
 149         struct expression *expr;
 150         struct symbol *type;
 151         char *member_name;
 152         int has_link = 0;
 153
 154         expr = get_faked_expression();
 155         if (!expr || expr->type != EXPR_ASSIGNMENT)
 156                 return 0;
 157         if (!is_void_pointer(expr->right))
 158                 return 0;
 159         member_name = get_member_name(expr->right);
 160         if (!member_name)
 161                 return 0;
 162
 163         type = get_type(expr->left);
 164         if (!type || type->type != SYM_PTR)
 165                 return 0;
 166         type = get_real_base_type(type);
 167         if (!type || type->type != SYM_STRUCT)
 168                 return 0;
 169
 170         run_sql(has_link_cb, &has_link,
 171                 "select * from data_info where type = %d and data = '%s' and value = '%s';",
 172                 TYPE_LINK, member_name, type_to_str(type));
 173         return has_link;
 174 }
 175
 176 static int is_ignored_macro(void)
 177 {
 178         struct expression *expr;
 179         char *name;
 180
 181         expr = get_faked_expression();
 182         if (!expr || expr->type != EXPR_ASSIGNMENT)
 183                 return 0;
 184         name = get_macro_name(expr->right->pos);
 185         if (!name)
 186                 return 0;
 187         if (strcmp(name, "container_of") == 0)
 188                 return 1;
 189         if (strcmp(name, "list_entry") == 0)
 190                 return 1;
 191         if (strstr(name, "for_each"))
 192                 return 1;
 193         return 0;
 194 }
 195
 196 static int is_uncasted_function(void)
 197 {
 198         struct expression *expr;
 199
 200         expr = get_faked_expression();
 201         if (!expr || expr->type != EXPR_ASSIGNMENT)
 202                 return 0;
 203         if (expr->right->type == EXPR_CALL)
 204                 return 1;
 205         return 0;
 206 }
 207
 208 static void match_assign_value(struct expression *expr)
 209 {
 210         char *member, *right_member;
 211         struct range_list *rl;
 212         struct symbol *type;
 213
 214         type = get_type(expr->left);
 215         if (type && type->type == SYM_STRUCT)
 216                 return;
 217
 218         member = get_member_name(expr->left);
 219         if (!member)
 220                 return;
 221
 222         /* if we're saying foo->mtu = bar->mtu then that doesn't add information */
 223         right_member = get_member_name(expr->right);
 224         if (right_member && strcmp(right_member, member) == 0)
 225                 goto free;
 226
 227         if (is_fake_call(expr->right)) {
 228                 if (is_ignored_macro())
 229                         goto free;
 230                 if (is_uncasted_function())
 231                         goto free;
 232                 add_fake_type_val(member, alloc_whole_rl(get_type(expr->left)), is_ignored_fake_assignment());
 233                 goto free;
 234         }
 235
 236         if (expr->op != '=') {
 237                 add_type_val(member, alloc_whole_rl(get_type(expr->left)));
 238                 goto free;
 239         }
 240         get_absolute_rl(expr->right, &rl);
 241         rl = cast_rl(type, rl);
 242         add_type_val(member, rl);
 243 free:
 244         free_string(right_member);
 245         free_string(member);
 246 }
 247
 248 /*
 249  * If we too:  int *p = &my_struct->member then abandon all hope of tracking
 250  * my_struct->member.
 251  */
 252 static void match_assign_pointer(struct expression *expr)
 253 {
 254         struct expression *right;
 255         char *member;
 256         struct range_list *rl;
 257         struct symbol *type;
 258
 259         right = strip_expr(expr->right);
 260         if (right->type != EXPR_PREOP || right->op != '&')
 261                 return;
 262         right = strip_expr(right->unop);
 263
 264         member = get_member_name(right);
 265         if (!member)
 266                 return;
 267         type = get_type(right);
 268         rl = alloc_whole_rl(type);
 269         add_type_val(member, rl);
 270         free_string(member);
 271 }
 272
 273 static void match_global_assign(struct expression *expr)
 274 {
 275         char *member;
 276         struct range_list *rl;
 277
 278         member = get_member_name(expr->left);
 279         if (!member)
 280                 return;
 281         get_absolute_rl(expr->right, &rl);
 282         add_global_type_val(member, rl);
 283         free_string(member);
 284 }
 285
 286 static void unop_expr(struct expression *expr)
 287 {
 288         struct range_list *rl;
 289         char *member;
 290
 291         if (expr->op != SPECIAL_DECREMENT && expr->op != SPECIAL_INCREMENT)
 292                 return;
 293
 294         expr = strip_expr(expr->unop);
 295         member = get_member_name(expr);
 296         if (!member)
 297                 return;
 298         rl = alloc_whole_rl(get_type(expr));
 299         add_type_val(member, rl);
 300         free_string(member);
 301 }
 302
 303 static void asm_expr(struct statement *stmt)
 304 {
 305         struct expression *expr;
 306         struct range_list *rl;
 307         char *member;
 308         int state = 0;
 309
 310         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 311                 switch (state) {
 312                 case 0: /* identifier */
 313                 case 1: /* constraint */
 314                         state++;
 315                         continue;
 316                 case 2: /* expression */
 317                         state = 0;
 318                         member = get_member_name(expr);
 319                         if (!member)
 320                                 continue;
 321                         rl = alloc_whole_rl(get_type(expr));
 322                         add_type_val(member, rl);
 323                         free_string(member);
 324                         continue;
 325                 }
 326         } END_FOR_EACH_PTR(expr);
 327 }
 328
 329 static void db_param_add(struct expression *expr, int param, char *key, char *value)
 330 {
 331         struct expression *arg;
 332         struct symbol *type;
 333         struct range_list *rl;
 334         char *member;
 335
 336         if (strcmp(key, "*$") != 0)
 337                 return;
 338
 339         while (expr->type == EXPR_ASSIGNMENT)
 340                 expr = strip_expr(expr->right);
 341         if (expr->type != EXPR_CALL)
 342                 return;
 343
 344         arg = get_argument_from_call_expr(expr->args, param);
 345         arg = strip_expr(arg);
 346         if (!arg)
 347                 return;
 348         type = get_member_type_from_key(arg, key);
 349         if (arg->type != EXPR_PREOP || arg->op != '&')
 350                 return;
 351         arg = strip_expr(arg->unop);
 352
 353         member = get_member_name(arg);
 354         if (!member)
 355                 return;
 356         call_results_to_rl(expr, type, value, &rl);
 357         add_type_val(member, rl);
 358         free_string(member);
 359 }
 360
 361 static void match_end_func_info(struct symbol *sym)
 362 {
 363         struct sm_state *sm;
 364
 365         FOR_EACH_SM(fn_type_val, sm) {
 366                 sql_insert_function_type_value(sm->name, sm->state->name);
 367         } END_FOR_EACH_SM(sm);
 368
 369         free_stree(&fn_type_val);
 370 }
 371
 372 static void match_end_file(struct symbol_list *sym_list)
 373 {
 374         struct sm_state *sm;
 375
 376         FOR_EACH_SM(global_type_val, sm) {
 377                 sql_insert_function_type_value(sm->name, sm->state->name);
 378         } END_FOR_EACH_SM(sm);
 379 }
 380
 381 void register_type_val(int id)
 382 {
 383         if (!option_info)
 384                 return;
 385
 386         my_id = id;
 387
 388         add_hook(&match_assign_value, ASSIGNMENT_HOOK);
 389         add_hook(&match_assign_pointer, ASSIGNMENT_HOOK);
 390         add_hook(&unop_expr, OP_HOOK);
 391         add_hook(&asm_expr, ASM_HOOK);
 392         select_return_states_hook(ADDED_VALUE, &db_param_add);
 393
 394         add_hook(&match_inline_start, INLINE_FN_START);
 395         add_hook(&match_inline_end, INLINE_FN_END);
 396
 397         add_hook(&match_end_func_info, END_FUNC_HOOK);
 398
 399         add_hook(&match_global_assign, GLOBAL_ASSIGNMENT_HOOK);
 400         add_hook(&match_end_file, END_FILE_HOOK);
 401
 402 }