1 /* 2 * Copyright (C) 2011 Oracle. All rights reserved. 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 * This is trying to make a list of the variables which 20 * have capped values. Sometimes we don't know what the 21 * cap is, for example if we are comparing variables but 22 * we don't know the values of the variables. In that 23 * case we only know that our variable is capped and we 24 * sort that information here. 25 */ 26 27 #include "smatch.h" 28 #include "smatch_slist.h" 29 #include "smatch_extra.h" 30 31 static int my_id; 32 33 STATE(capped); 34 STATE(uncapped); 35 36 static void set_uncapped(struct sm_state *sm, struct expression *mod_expr) 37 { 38 set_state(my_id, sm->name, sm->sym, &uncapped); 39 } 40 41 static struct smatch_state *unmatched_state(struct sm_state *sm) 42 { 43 struct smatch_state *state; 44 45 state = __get_state(SMATCH_EXTRA, sm->name, sm->sym); 46 if (state && !estate_is_whole(state)) 47 return &capped; 48 return &uncapped; 49 } 50 51 static int is_capped_macro(struct expression *expr) 52 { 53 char *name; 54 55 name = get_macro_name(expr->pos); 56 if (!name) 57 return 0; 58 59 if (strcmp(name, "min") == 0) 60 return 1; 61 if (strcmp(name, "MIN") == 0) 62 return 1; 63 if (strcmp(name, "min_t") == 0) 64 return 1; 65 66 return 0; 67 } 68 69 int is_capped(struct expression *expr) 70 { 71 struct symbol *type; 72 sval_t dummy; 73 74 expr = strip_expr(expr); 75 while (expr && expr->type == EXPR_POSTOP) { 76 expr = strip_expr(expr->unop); 77 } 78 if (!expr) 79 return 0; 80 81 type = get_type(expr); 82 if (is_ptr_type(type)) 83 return 0; 84 if (type == &bool_ctype) 85 return 0; 86 if (type_bits(type) >= 0 && type_bits(type) <= 2) 87 return 0; 88 89 if (get_hard_max(expr, &dummy)) 90 return 1; 91 92 if (is_capped_macro(expr)) 93 return 1; 94 95 if (expr->type == EXPR_BINOP) { 96 struct range_list *left_rl, *right_rl; 97 98 if (expr->op == '&') 99 return 1; 100 if (expr->op == SPECIAL_RIGHTSHIFT) 101 return 1; 102 if (expr->op == '%' && is_capped(expr->right)) 103 return 1; 104 if (!is_capped(expr->left)) 105 return 0; 106 if (expr->op == '/') 107 return 1; 108 if (!is_capped(expr->right)) 109 return 0; 110 if (expr->op == '*') { 111 get_absolute_rl(expr->left, &left_rl); 112 get_absolute_rl(expr->right, &right_rl); 113 if (sval_is_negative(rl_min(left_rl)) || 114 sval_is_negative(rl_min(right_rl))) 115 return 0; 116 } 117 return 1; 118 } 119 if (get_state_expr(my_id, expr) == &capped) 120 return 1; 121 return 0; 122 } 123 124 int is_capped_var_sym(const char *name, struct symbol *sym) 125 { 126 if (get_state(my_id, name, sym) == &capped) 127 return 1; 128 return 0; 129 } 130 131 void set_param_capped_data(const char *name, struct symbol *sym, char *key, char *value) 132 { 133 char fullname[256]; 134 135 if (strncmp(key, "$", 1)) 136 return; 137 snprintf(fullname, 256, "%s%s", name, key + 1); 138 set_state(my_id, fullname, sym, &capped); 139 } 140 141 static void match_condition(struct expression *expr) 142 { 143 struct expression *left, *right; 144 struct smatch_state *left_true = NULL; 145 struct smatch_state *left_false = NULL; 146 struct smatch_state *right_true = NULL; 147 struct smatch_state *right_false = NULL; 148 sval_t sval; 149 150 151 if (expr->type != EXPR_COMPARE) 152 return; 153 154 left = strip_expr(expr->left); 155 right = strip_expr(expr->right); 156 157 while (left->type == EXPR_ASSIGNMENT) 158 left = strip_expr(left->left); 159 160 /* If we're dealing with known expressions, that's for smatch_extra.c */ 161 if (get_implied_value(left, &sval) || 162 get_implied_value(right, &sval)) 163 return; 164 165 switch (expr->op) { 166 case '<': 167 case SPECIAL_LTE: 168 case SPECIAL_UNSIGNED_LT: 169 case SPECIAL_UNSIGNED_LTE: 170 left_true = &capped; 171 right_false = &capped; 172 break; 173 case '>': 174 case SPECIAL_GTE: 175 case SPECIAL_UNSIGNED_GT: 176 case SPECIAL_UNSIGNED_GTE: 177 left_false = &capped; 178 right_true = &capped; 179 break; 180 case SPECIAL_EQUAL: 181 left_true = &capped; 182 right_true = &capped; 183 break; 184 case SPECIAL_NOTEQUAL: 185 left_false = &capped; 186 right_false = &capped; 187 break; 188 189 default: 190 return; 191 } 192 193 set_true_false_states_expr(my_id, left, left_true, left_false); 194 set_true_false_states_expr(my_id, right, right_true, right_false); 195 } 196 197 static void match_assign(struct expression *expr) 198 { 199 struct symbol *type; 200 201 type = get_type(expr); 202 if (is_ptr_type(type)) 203 return; 204 if (type == &bool_ctype) 205 return; 206 if (type_bits(type) >= 0 && type_bits(type) <= 2) 207 return; 208 209 if (is_capped(expr->right)) { 210 set_state_expr(my_id, expr->left, &capped); 211 } else { 212 if (get_state_expr(my_id, expr->left)) 213 set_state_expr(my_id, expr->left, &uncapped); 214 } 215 } 216 217 static void match_caller_info(struct expression *expr) 218 { 219 struct expression *tmp; 220 sval_t sval; 221 int i; 222 223 i = -1; 224 FOR_EACH_PTR(expr->args, tmp) { 225 i++; 226 if (get_implied_value(tmp, &sval)) 227 continue; 228 if (!is_capped(tmp)) 229 continue; 230 sql_insert_caller_info(expr, CAPPED_DATA, i, "$", "1"); 231 } END_FOR_EACH_PTR(tmp); 232 } 233 234 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm) 235 { 236 struct smatch_state *estate; 237 sval_t sval; 238 239 if (sm->state != &capped) 240 return; 241 estate = __get_state(SMATCH_EXTRA, sm->name, sm->sym); 242 if (estate_get_single_value(estate, &sval)) 243 return; 244 sql_insert_caller_info(call, CAPPED_DATA, param, printed_name, "1"); 245 } 246 247 static void print_return_implies_capped(int return_id, char *return_ranges, struct expression *expr) 248 { 249 struct smatch_state *orig, *estate; 250 struct sm_state *sm; 251 struct symbol *ret_sym; 252 const char *param_name; 253 char *return_str; 254 int param; 255 sval_t sval; 256 bool return_found = false; 257 258 expr = strip_expr(expr); 259 return_str = expr_to_str(expr); 260 ret_sym = expr_to_sym(expr); 261 262 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) { 263 if (sm->state != &capped) 264 continue; 265 266 param = get_param_num_from_sym(sm->sym); 267 if (param < 0) 268 continue; 269 270 estate = __get_state(SMATCH_EXTRA, sm->name, sm->sym); 271 if (estate_get_single_value(estate, &sval)) 272 continue; 273 274 orig = get_state_stree(get_start_states(), my_id, sm->name, sm->sym); 275 if (orig == &capped && !param_was_set_var_sym(sm->name, sm->sym)) 276 continue; 277 278 param_name = get_param_name(sm); 279 if (!param_name) 280 continue; 281 282 sql_insert_return_states(return_id, return_ranges, CAPPED_DATA, 283 param, param_name, "1"); 284 } END_FOR_EACH_SM(sm); 285 286 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) { 287 if (!ret_sym) 288 break; 289 if (sm->state != &capped) 290 continue; 291 if (ret_sym != sm->sym) 292 continue; 293 294 estate = __get_state(SMATCH_EXTRA, sm->name, sm->sym); 295 if (estate_get_single_value(estate, &sval)) 296 continue; 297 298 param_name = state_name_to_param_name(sm->name, return_str); 299 if (!param_name) 300 continue; 301 if (strcmp(param_name, "$") == 0) 302 return_found = true; 303 sql_insert_return_states(return_id, return_ranges, CAPPED_DATA, 304 -1, param_name, "1"); 305 } END_FOR_EACH_SM(sm); 306 307 if (return_found) 308 goto free_string; 309 310 if (option_project == PROJ_KERNEL && get_function() && 311 strstr(get_function(), "nla_get_")) 312 sql_insert_return_states(return_id, return_ranges, CAPPED_DATA, 313 -1, "$", "1"); 314 315 free_string: 316 free_string(return_str); 317 } 318 319 static void db_return_states_capped(struct expression *expr, int param, char *key, char *value) 320 { 321 char *name; 322 struct symbol *sym; 323 324 name = return_state_to_var_sym(expr, param, key, &sym); 325 if (!name || !sym) 326 goto free; 327 328 set_state(my_id, name, sym, &capped); 329 free: 330 free_string(name); 331 } 332 333 void register_capped(int id) 334 { 335 my_id = id; 336 337 add_unmatched_state_hook(my_id, &unmatched_state); 338 select_caller_info_hook(set_param_capped_data, CAPPED_DATA); 339 add_hook(&match_condition, CONDITION_HOOK); 340 add_hook(&match_assign, ASSIGNMENT_HOOK); 341 add_modification_hook(my_id, &set_uncapped); 342 343 add_hook(&match_caller_info, FUNCTION_CALL_HOOK); 344 add_member_info_callback(my_id, struct_member_callback); 345 346 add_split_return_callback(print_return_implies_capped); 347 select_return_states_hook(CAPPED_DATA, &db_return_states_capped); 348 } 349