1 /*
2 * Copyright (C) 2016 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 #include <ctype.h>
19
20 #include "smatch.h"
21 #include "smatch_extra.h"
22 #include "smatch_slist.h"
23
24 static int my_id;
25
26 STATE(inc);
27 STATE(start_state);
28 STATE(dec);
29
30 static struct smatch_state *unmatched_state(struct sm_state *sm)
31 {
32 /*
33 * We default to decremented. For example, say we have:
34 * if (p)
35 * atomic_dec(p);
36 * <- p is decreemented.
37 *
38 */
39 if ((sm->state == &dec) &&
40 parent_is_gone_var_sym(sm->name, sm->sym))
41 return sm->state;
42 return &start_state;
43 }
44
45 static struct stree *start_states;
46 static struct stree_stack *saved_stack;
47 static void set_start_state(const char *name, struct symbol *sym, struct smatch_state *start)
48 {
49 struct smatch_state *orig;
50
51 orig = get_state_stree(start_states, my_id, name, sym);
52 if (!orig)
53 set_state_stree(&start_states, my_id, name, sym, start);
54 else if (orig != start)
55 set_state_stree(&start_states, my_id, name, sym, &undefined);
56 }
57
58 static struct sm_state *get_best_match(const char *key)
59 {
60 struct sm_state *sm;
61 struct sm_state *match;
62 int cnt = 0;
63 int start_pos, state_len, key_len, chunks, i;
64
65 if (strncmp(key, "$->", 3) == 0)
66 key += 3;
67
68 key_len = strlen(key);
69 chunks = 0;
70 for (i = key_len - 1; i > 0; i--) {
71 if (key[i] == '>' || key[i] == '.')
72 chunks++;
73 if (chunks == 2) {
74 key += (i + 1);
75 key_len = strlen(key);
76 break;
77 }
78 }
79
80 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
81 state_len = strlen(sm->name);
82 if (state_len < key_len)
83 continue;
84 start_pos = state_len - key_len;
85 if ((start_pos == 0 || !isalnum(sm->name[start_pos - 1])) &&
86 strcmp(sm->name + start_pos, key) == 0) {
87 cnt++;
88 match = sm;
89 }
90 } END_FOR_EACH_SM(sm);
91
92 if (cnt == 1)
93 return match;
94 return NULL;
95 }
96
97 static void db_inc_dec(struct expression *expr, int param, const char *key, int inc_dec)
98 {
99 struct sm_state *start_sm;
100 struct expression *arg;
101 char *name;
102 struct symbol *sym;
103 bool free_at_end = true;
104
105 while (expr->type == EXPR_ASSIGNMENT)
106 expr = strip_expr(expr->right);
107 if (expr->type != EXPR_CALL)
108 return;
109
110 arg = get_argument_from_call_expr(expr->args, param);
111 if (!arg)
112 return;
113
114 name = get_variable_from_key(arg, key, &sym);
115 if (!name || !sym)
116 goto free;
117
118 start_sm = get_sm_state(my_id, name, sym);
119 if (!start_sm && inc_dec == ATOMIC_DEC) {
120 start_sm = get_best_match(key);
121 if (start_sm) {
122 free_string(name);
123 free_at_end = false;
124 name = (char *)start_sm->name;
125 sym = start_sm->sym;
126 }
127 }
128
129 if (inc_dec == ATOMIC_INC) {
130 if (!start_sm)
131 set_start_state(name, sym, &dec);
132 // set_refcount_inc(name, sym);
133 set_state(my_id, name, sym, &inc);
134 } else {
135 // set_refcount_dec(name, sym);
136 if (!start_sm)
137 set_start_state(name, sym, &inc);
138
139 if (start_sm && start_sm->state == &inc)
140 set_state(my_id, name, sym, &start_state);
141 else
142 set_state(my_id, name, sym, &dec);
143 }
144
145 free:
146 if (free_at_end)
147 free_string(name);
148 }
149
150 static const char *primitive_funcs[] = {
151 "atomic_inc_return",
152 "atomic_add_return",
153 "atomic_sub_return",
154 "atomic_sub_and_test",
155 "atomic_dec_and_test",
156 "_atomic_dec_and_lock",
157 "atomic_dec",
158 "atomic_long_inc",
159 "atomic_long_dec",
160 "atomic_inc",
161 "atomic_sub",
162 "refcount_inc",
163 "refcount_dec",
164 "refcount_add",
165 "refcount_add_not_zero",
166 "refcount_inc_not_zero",
167 "refcount_sub_and_test",
168 "refcount_dec_and_test",
169 "atomic_dec_if_positive",
170 };
171
172 static bool is_inc_dec_primitive(struct expression *expr)
173 {
174 int i;
175
176 while (expr->type == EXPR_ASSIGNMENT)
177 expr = strip_expr(expr->right);
178 if (expr->type != EXPR_CALL)
179 return false;
180
181 if (expr->fn->type != EXPR_SYMBOL)
182 return false;
183
184 for (i = 0; i < ARRAY_SIZE(primitive_funcs); i++) {
185 if (sym_name_is(primitive_funcs[i], expr->fn))
186 return true;
187 }
188
189 return false;
190 }
191
192 static void db_inc(struct expression *expr, int param, char *key, char *value)
193 {
194 if (is_inc_dec_primitive(expr))
195 return;
196 db_inc_dec(expr, param, key, ATOMIC_INC);
197 }
198
199 static void db_dec(struct expression *expr, int param, char *key, char *value)
200 {
201 if (is_inc_dec_primitive(expr))
202 return;
203 db_inc_dec(expr, param, key, ATOMIC_DEC);
204 }
205
206 static void match_atomic_inc(const char *fn, struct expression *expr, void *_unused)
207 {
208 db_inc_dec(expr, 0, "$->counter", ATOMIC_INC);
209 }
210
211 static void match_atomic_dec(const char *fn, struct expression *expr, void *_unused)
212 {
213 db_inc_dec(expr, 0, "$->counter", ATOMIC_DEC);
214 }
215
216 static void match_atomic_add(const char *fn, struct expression *expr, void *_unused)
217 {
218 struct expression *amount;
219 sval_t sval;
220
221 amount = get_argument_from_call_expr(expr->args, 0);
222 if (get_implied_value(amount, &sval) && sval_is_negative(sval)) {
223 db_inc_dec(expr, 1, "$->counter", ATOMIC_DEC);
224 return;
225 }
226
227 db_inc_dec(expr, 1, "$->counter", ATOMIC_INC);
228 }
229
230 static void match_atomic_sub(const char *fn, struct expression *expr, void *_unused)
231 {
232 db_inc_dec(expr, 1, "$->counter", ATOMIC_DEC);
233 }
234
235 static void refcount_inc(const char *fn, struct expression *expr, void *param)
236 {
237 db_inc_dec(expr, PTR_INT(param), "$->ref.counter", ATOMIC_INC);
238 }
239
240 static void refcount_dec(const char *fn, struct expression *expr, void *param)
241 {
242 db_inc_dec(expr, PTR_INT(param), "$->ref.counter", ATOMIC_DEC);
243 }
244
245 static void pm_runtime_get_sync(const char *fn, struct expression *expr, void *param)
246 {
247 db_inc_dec(expr, PTR_INT(param), "$->power.usage_count.counter", ATOMIC_INC);
248 }
249
250 static void match_implies_inc(const char *fn, struct expression *call_expr,
251 struct expression *assign_expr, void *param)
252 {
253 db_inc_dec(call_expr, PTR_INT(param), "$->ref.counter", ATOMIC_INC);
254 }
255
256 static void match_implies_atomic_dec(const char *fn, struct expression *call_expr,
257 struct expression *assign_expr, void *param)
258 {
259 db_inc_dec(call_expr, PTR_INT(param), "$->counter", ATOMIC_DEC);
260 }
261
262 static bool is_maybe_dec(struct sm_state *sm)
263 {
264 if (sm->state == &dec)
265 return true;
266 if (slist_has_state(sm->possible, &dec) &&
267 !slist_has_state(sm->possible, &inc))
268 return true;
269 return false;
270 }
271
272 static void match_return_info(int return_id, char *return_ranges, struct expression *expr)
273 {
274 struct sm_state *sm;
275 const char *param_name;
276 int param;
277
278 if (is_impossible_path())
279 return;
280
281 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
282 if (sm->state != &inc && !is_maybe_dec(sm))
283 continue;
284 if (sm->state == get_state_stree(start_states, my_id, sm->name, sm->sym))
285 continue;
286 if (parent_is_gone_var_sym(sm->name, sm->sym))
287 continue;
288 param = get_param_num_from_sym(sm->sym);
289 if (param < 0)
290 continue;
291 param_name = get_param_name(sm);
292 if (!param_name)
293 continue;
294 sql_insert_return_states(return_id, return_ranges,
295 (sm->state == &inc) ? ATOMIC_INC : ATOMIC_DEC,
296 param, param_name, "");
297 } END_FOR_EACH_SM(sm);
298 }
299
300 enum {
301 EMPTY, NEGATIVE, ZERO, POSITIVE, NUM_BUCKETS
302 };
303
304 static int success_fail_positive(struct range_list *rl)
305 {
306 if (!rl)
307 return EMPTY;
308
309 if (!is_whole_rl(rl) && sval_is_negative(rl_min(rl)))
310 return NEGATIVE;
311
312 if (rl_min(rl).value == 0)
313 return ZERO;
314
315 return POSITIVE;
316 }
317
318 static void check_counter(const char *name, struct symbol *sym)
319 {
320 struct range_list *inc_lines = NULL;
321 struct range_list *dec_lines = NULL;
322 int inc_buckets[NUM_BUCKETS] = {};
323 int dec_buckets[NUM_BUCKETS] = {};
324 struct stree *stree, *orig_stree;
325 struct smatch_state *state;
326 struct sm_state *return_sm;
327 struct sm_state *sm;
328 sval_t line = sval_type_val(&int_ctype, 0);
329 int bucket;
330
331 /* static variable are probably just counters */
332 if (sym->ctype.modifiers & MOD_STATIC &&
333 !(sym->ctype.modifiers & MOD_TOPLEVEL))
334 return;
335
336 FOR_EACH_PTR(get_all_return_strees(), stree) {
337 orig_stree = __swap_cur_stree(stree);
338
339 if (is_impossible_path())
340 goto swap_stree;
341
342 return_sm = get_sm_state(RETURN_ID, "return_ranges", NULL);
343 if (!return_sm)
344 goto swap_stree;
345 line.value = return_sm->line;
346
347 if (get_state_stree(start_states, my_id, name, sym) == &inc)
348 goto swap_stree;
349
350 if (parent_is_gone_var_sym(name, sym))
351 goto swap_stree;
352
353 sm = get_sm_state(my_id, name, sym);
354 if (sm)
355 state = sm->state;
356 else
357 state = &start_state;
358
359 if (state != &inc &&
360 state != &dec &&
361 state != &start_state)
362 goto swap_stree;
363
364 bucket = success_fail_positive(estate_rl(return_sm->state));
365
366 if (state == &inc) {
367 add_range(&inc_lines, line, line);
368 inc_buckets[bucket] = true;
369 }
370 if (state == &dec || state == &start_state) {
371 add_range(&dec_lines, line, line);
372 dec_buckets[bucket] = true;
373 }
374 swap_stree:
375 __swap_cur_stree(orig_stree);
376 } END_FOR_EACH_PTR(stree);
377
378 if (inc_buckets[NEGATIVE] &&
379 inc_buckets[ZERO]) {
380 // sm_warning("XXX '%s' not decremented on lines: %s.", name, show_rl(inc_lines));
381 }
382
383 }
384
385 static void match_check_missed(struct symbol *sym)
386 {
387 struct sm_state *sm;
388
389 FOR_EACH_MY_SM(my_id, get_all_return_states(), sm) {
390 check_counter(sm->name, sm->sym);
391 } END_FOR_EACH_SM(sm);
392 }
393
394 int on_atomic_dec_path(void)
395 {
396 struct sm_state *sm;
397
398 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
399 if (sm->state == &dec)
400 return 1;
401 } END_FOR_EACH_SM(sm);
402
403 return 0;
404 }
405
406 int was_inced(const char *name, struct symbol *sym)
407 {
408 return get_state(my_id, name, sym) == &inc;
409 }
410
411 static void match_save_states(struct expression *expr)
412 {
413 push_stree(&saved_stack, start_states);
414 start_states = NULL;
415 }
416
417 static void match_restore_states(struct expression *expr)
418 {
419 start_states = pop_stree(&saved_stack);
420 }
421
422 static void match_after_func(struct symbol *sym)
423 {
424 free_stree(&start_states);
425 }
426
427 void check_atomic_inc_dec(int id)
428 {
429 my_id = id;
430
431 if (option_project != PROJ_KERNEL)
432 return;
433
434 add_unmatched_state_hook(my_id, &unmatched_state);
435
436 add_split_return_callback(match_return_info);
437 select_return_states_hook(ATOMIC_INC, &db_inc);
438 select_return_states_hook(ATOMIC_DEC, &db_dec);
439
440 add_function_hook("atomic_inc_return", &match_atomic_inc, NULL);
441 add_function_hook("atomic_add_return", &match_atomic_add, NULL);
442 add_function_hook("atomic_sub_return", &match_atomic_sub, NULL);
443 add_function_hook("atomic_sub_and_test", &match_atomic_sub, NULL);
444 add_function_hook("atomic_long_sub_and_test", &match_atomic_sub, NULL);
445 add_function_hook("atomic64_sub_and_test", &match_atomic_sub, NULL);
446 add_function_hook("atomic_dec_and_test", &match_atomic_dec, NULL);
447 add_function_hook("atomic_long_dec_and_test", &match_atomic_dec, NULL);
448 add_function_hook("atomic64_dec_and_test", &match_atomic_dec, NULL);
449 add_function_hook("_atomic_dec_and_lock", &match_atomic_dec, NULL);
450 add_function_hook("atomic_dec", &match_atomic_dec, NULL);
451 add_function_hook("atomic_dec_return", &match_atomic_dec, NULL);
452 add_function_hook("atomic_long_inc", &match_atomic_inc, NULL);
453 add_function_hook("atomic_long_dec", &match_atomic_dec, NULL);
454 add_function_hook("atomic_inc", &match_atomic_inc, NULL);
455 add_function_hook("atomic_sub", &match_atomic_sub, NULL);
456
457 add_function_hook("refcount_inc", &refcount_inc, INT_PTR(0));
458 add_function_hook("refcount_dec", &refcount_dec, INT_PTR(0));
459 add_function_hook("refcount_add", &refcount_inc, INT_PTR(1));
460
461 return_implies_state("refcount_add_not_zero", 1, 1, &match_implies_inc, INT_PTR(1));
462 return_implies_state("refcount_inc_not_zero", 1, 1, &match_implies_inc, INT_PTR(0));
463
464 return_implies_state("atomic_dec_if_positive", 0, INT_MAX, &match_implies_atomic_dec, INT_PTR(0));
465
466 add_function_hook("refcount_sub_and_test", &refcount_dec, INT_PTR(1));
467 add_function_hook("refcount_dec_and_test", &refcount_dec, INT_PTR(0));
468
469 add_function_hook("pm_runtime_get_sync", &pm_runtime_get_sync, INT_PTR(0));
470
471 add_hook(&match_check_missed, END_FUNC_HOOK);
472
473 add_hook(&match_after_func, AFTER_FUNC_HOOK);
474 add_hook(&match_save_states, INLINE_FN_START);
475 add_hook(&match_restore_states, INLINE_FN_END);
476 }