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cpumask: remove obsolete topology_core_siblings and topology_thread_siblings: ia64
[linux-2.6/btrfs-unstable.git] / kernel / trace / trace_events_filter.c
blob23245785927f8dfb6810313db3fcc19f3aa0d8e6
1 /*
2 * trace_events_filter - generic event filtering
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (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, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
19 */
20
21 #include <linux/debugfs.h>
22 #include <linux/uaccess.h>
23 #include <linux/module.h>
24 #include <linux/ctype.h>
25 #include <linux/mutex.h>
26
27 #include "trace.h"
28 #include "trace_output.h"
29
30 enum filter_op_ids
31 {
32 OP_OR,
33 OP_AND,
34 OP_NE,
35 OP_EQ,
36 OP_LT,
37 OP_LE,
38 OP_GT,
39 OP_GE,
40 OP_NONE,
41 OP_OPEN_PAREN,
42 };
43
44 struct filter_op {
45 int id;
46 char *string;
47 int precedence;
48 };
49
50 static struct filter_op filter_ops[] = {
51 { OP_OR, "||", 1 },
52 { OP_AND, "&&", 2 },
53 { OP_NE, "!=", 4 },
54 { OP_EQ, "==", 4 },
55 { OP_LT, "<", 5 },
56 { OP_LE, "<=", 5 },
57 { OP_GT, ">", 5 },
58 { OP_GE, ">=", 5 },
59 { OP_NONE, "OP_NONE", 0 },
60 { OP_OPEN_PAREN, "(", 0 },
61 };
62
63 enum {
64 FILT_ERR_NONE,
65 FILT_ERR_INVALID_OP,
66 FILT_ERR_UNBALANCED_PAREN,
67 FILT_ERR_TOO_MANY_OPERANDS,
68 FILT_ERR_OPERAND_TOO_LONG,
69 FILT_ERR_FIELD_NOT_FOUND,
70 FILT_ERR_ILLEGAL_FIELD_OP,
71 FILT_ERR_ILLEGAL_INTVAL,
72 FILT_ERR_BAD_SUBSYS_FILTER,
73 FILT_ERR_TOO_MANY_PREDS,
74 FILT_ERR_MISSING_FIELD,
75 FILT_ERR_INVALID_FILTER,
76 };
77
78 static char *err_text[] = {
79 "No error",
80 "Invalid operator",
81 "Unbalanced parens",
82 "Too many operands",
83 "Operand too long",
84 "Field not found",
85 "Illegal operation for field type",
86 "Illegal integer value",
87 "Couldn't find or set field in one of a subsystem's events",
88 "Too many terms in predicate expression",
89 "Missing field name and/or value",
90 "Meaningless filter expression",
91 };
92
93 struct opstack_op {
94 int op;
95 struct list_head list;
96 };
97
98 struct postfix_elt {
99 int op;
100 char *operand;
101 struct list_head list;
102 };
103
104 struct filter_parse_state {
105 struct filter_op *ops;
106 struct list_head opstack;
107 struct list_head postfix;
108 int lasterr;
109 int lasterr_pos;
110
111 struct {
112 char *string;
113 unsigned int cnt;
114 unsigned int tail;
115 } infix;
116
117 struct {
118 char string[MAX_FILTER_STR_VAL];
119 int pos;
120 unsigned int tail;
121 } operand;
122 };
123
124 #define DEFINE_COMPARISON_PRED(type) \
125 static int filter_pred_##type(struct filter_pred *pred, void *event, \
126 int val1, int val2) \
127 { \
128 type *addr = (type *)(event + pred->offset); \
129 type val = (type)pred->val; \
130 int match = 0; \
131 \
132 switch (pred->op) { \
133 case OP_LT: \
134 match = (*addr < val); \
135 break; \
136 case OP_LE: \
137 match = (*addr <= val); \
138 break; \
139 case OP_GT: \
140 match = (*addr > val); \
141 break; \
142 case OP_GE: \
143 match = (*addr >= val); \
144 break; \
145 default: \
146 break; \
147 } \
148 \
149 return match; \
150 }
151
152 #define DEFINE_EQUALITY_PRED(size) \
153 static int filter_pred_##size(struct filter_pred *pred, void *event, \
154 int val1, int val2) \
155 { \
156 u##size *addr = (u##size *)(event + pred->offset); \
157 u##size val = (u##size)pred->val; \
158 int match; \
159 \
160 match = (val == *addr) ^ pred->not; \
161 \
162 return match; \
163 }
164
165 DEFINE_COMPARISON_PRED(s64);
166 DEFINE_COMPARISON_PRED(u64);
167 DEFINE_COMPARISON_PRED(s32);
168 DEFINE_COMPARISON_PRED(u32);
169 DEFINE_COMPARISON_PRED(s16);
170 DEFINE_COMPARISON_PRED(u16);
171 DEFINE_COMPARISON_PRED(s8);
172 DEFINE_COMPARISON_PRED(u8);
173
174 DEFINE_EQUALITY_PRED(64);
175 DEFINE_EQUALITY_PRED(32);
176 DEFINE_EQUALITY_PRED(16);
177 DEFINE_EQUALITY_PRED(8);
178
179 static int filter_pred_and(struct filter_pred *pred __attribute((unused)),
180 void *event __attribute((unused)),
181 int val1, int val2)
182 {
183 return val1 && val2;
184 }
185
186 static int filter_pred_or(struct filter_pred *pred __attribute((unused)),
187 void *event __attribute((unused)),
188 int val1, int val2)
189 {
190 return val1 || val2;
191 }
192
193 /* Filter predicate for fixed sized arrays of characters */
194 static int filter_pred_string(struct filter_pred *pred, void *event,
195 int val1, int val2)
196 {
197 char *addr = (char *)(event + pred->offset);
198 int cmp, match;
199
200 cmp = strncmp(addr, pred->str_val, pred->str_len);
201
202 match = (!cmp) ^ pred->not;
203
204 return match;
205 }
206
207 /* Filter predicate for char * pointers */
208 static int filter_pred_pchar(struct filter_pred *pred, void *event,
209 int val1, int val2)
210 {
211 char **addr = (char **)(event + pred->offset);
212 int cmp, match;
213
214 cmp = strncmp(*addr, pred->str_val, pred->str_len);
215
216 match = (!cmp) ^ pred->not;
217
218 return match;
219 }
220
221 /*
222 * Filter predicate for dynamic sized arrays of characters.
223 * These are implemented through a list of strings at the end
224 * of the entry.
225 * Also each of these strings have a field in the entry which
226 * contains its offset from the beginning of the entry.
227 * We have then first to get this field, dereference it
228 * and add it to the address of the entry, and at last we have
229 * the address of the string.
230 */
231 static int filter_pred_strloc(struct filter_pred *pred, void *event,
232 int val1, int val2)
233 {
234 u32 str_item = *(u32 *)(event + pred->offset);
235 int str_loc = str_item & 0xffff;
236 int str_len = str_item >> 16;
237 char *addr = (char *)(event + str_loc);
238 int cmp, match;
239
240 cmp = strncmp(addr, pred->str_val, str_len);
241
242 match = (!cmp) ^ pred->not;
243
244 return match;
245 }
246
247 static int filter_pred_none(struct filter_pred *pred, void *event,
248 int val1, int val2)
249 {
250 return 0;
251 }
252
253 /* return 1 if event matches, 0 otherwise (discard) */
254 int filter_match_preds(struct ftrace_event_call *call, void *rec)
255 {
256 struct event_filter *filter = call->filter;
257 int match, top = 0, val1 = 0, val2 = 0;
258 int stack[MAX_FILTER_PRED];
259 struct filter_pred *pred;
260 int i;
261
262 for (i = 0; i < filter->n_preds; i++) {
263 pred = filter->preds[i];
264 if (!pred->pop_n) {
265 match = pred->fn(pred, rec, val1, val2);
266 stack[top++] = match;
267 continue;
268 }
269 if (pred->pop_n > top) {
270 WARN_ON_ONCE(1);
271 return 0;
272 }
273 val1 = stack[--top];
274 val2 = stack[--top];
275 match = pred->fn(pred, rec, val1, val2);
276 stack[top++] = match;
277 }
278
279 return stack[--top];
280 }
281 EXPORT_SYMBOL_GPL(filter_match_preds);
282
283 static void parse_error(struct filter_parse_state *ps, int err, int pos)
284 {
285 ps->lasterr = err;
286 ps->lasterr_pos = pos;
287 }
288
289 static void remove_filter_string(struct event_filter *filter)
290 {
291 kfree(filter->filter_string);
292 filter->filter_string = NULL;
293 }
294
295 static int replace_filter_string(struct event_filter *filter,
296 char *filter_string)
297 {
298 kfree(filter->filter_string);
299 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
300 if (!filter->filter_string)
301 return -ENOMEM;
302
303 return 0;
304 }
305
306 static int append_filter_string(struct event_filter *filter,
307 char *string)
308 {
309 int newlen;
310 char *new_filter_string;
311
312 BUG_ON(!filter->filter_string);
313 newlen = strlen(filter->filter_string) + strlen(string) + 1;
314 new_filter_string = kmalloc(newlen, GFP_KERNEL);
315 if (!new_filter_string)
316 return -ENOMEM;
317
318 strcpy(new_filter_string, filter->filter_string);
319 strcat(new_filter_string, string);
320 kfree(filter->filter_string);
321 filter->filter_string = new_filter_string;
322
323 return 0;
324 }
325
326 static void append_filter_err(struct filter_parse_state *ps,
327 struct event_filter *filter)
328 {
329 int pos = ps->lasterr_pos;
330 char *buf, *pbuf;
331
332 buf = (char *)__get_free_page(GFP_TEMPORARY);
333 if (!buf)
334 return;
335
336 append_filter_string(filter, "\n");
337 memset(buf, ' ', PAGE_SIZE);
338 if (pos > PAGE_SIZE - 128)
339 pos = 0;
340 buf[pos] = '^';
341 pbuf = &buf[pos] + 1;
342
343 sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
344 append_filter_string(filter, buf);
345 free_page((unsigned long) buf);
346 }
347
348 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
349 {
350 struct event_filter *filter = call->filter;
351
352 mutex_lock(&event_mutex);
353 if (filter && filter->filter_string)
354 trace_seq_printf(s, "%s\n", filter->filter_string);
355 else
356 trace_seq_printf(s, "none\n");
357 mutex_unlock(&event_mutex);
358 }
359
360 void print_subsystem_event_filter(struct event_subsystem *system,
361 struct trace_seq *s)
362 {
363 struct event_filter *filter = system->filter;
364
365 mutex_lock(&event_mutex);
366 if (filter && filter->filter_string)
367 trace_seq_printf(s, "%s\n", filter->filter_string);
368 else
369 trace_seq_printf(s, "none\n");
370 mutex_unlock(&event_mutex);
371 }
372
373 static struct ftrace_event_field *
374 find_event_field(struct ftrace_event_call *call, char *name)
375 {
376 struct ftrace_event_field *field;
377
378 list_for_each_entry(field, &call->fields, link) {
379 if (!strcmp(field->name, name))
380 return field;
381 }
382
383 return NULL;
384 }
385
386 static void filter_free_pred(struct filter_pred *pred)
387 {
388 if (!pred)
389 return;
390
391 kfree(pred->field_name);
392 kfree(pred);
393 }
394
395 static void filter_clear_pred(struct filter_pred *pred)
396 {
397 kfree(pred->field_name);
398 pred->field_name = NULL;
399 pred->str_len = 0;
400 }
401
402 static int filter_set_pred(struct filter_pred *dest,
403 struct filter_pred *src,
404 filter_pred_fn_t fn)
405 {
406 *dest = *src;
407 if (src->field_name) {
408 dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
409 if (!dest->field_name)
410 return -ENOMEM;
411 }
412 dest->fn = fn;
413
414 return 0;
415 }
416
417 static void filter_disable_preds(struct ftrace_event_call *call)
418 {
419 struct event_filter *filter = call->filter;
420 int i;
421
422 call->filter_active = 0;
423 filter->n_preds = 0;
424
425 for (i = 0; i < MAX_FILTER_PRED; i++)
426 filter->preds[i]->fn = filter_pred_none;
427 }
428
429 void destroy_preds(struct ftrace_event_call *call)
430 {
431 struct event_filter *filter = call->filter;
432 int i;
433
434 if (!filter)
435 return;
436
437 for (i = 0; i < MAX_FILTER_PRED; i++) {
438 if (filter->preds[i])
439 filter_free_pred(filter->preds[i]);
440 }
441 kfree(filter->preds);
442 kfree(filter->filter_string);
443 kfree(filter);
444 call->filter = NULL;
445 }
446
447 static int init_preds(struct ftrace_event_call *call)
448 {
449 struct event_filter *filter;
450 struct filter_pred *pred;
451 int i;
452
453 if (call->filter)
454 return 0;
455
456 filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
457 if (!call->filter)
458 return -ENOMEM;
459
460 filter->n_preds = 0;
461
462 filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
463 if (!filter->preds)
464 goto oom;
465
466 for (i = 0; i < MAX_FILTER_PRED; i++) {
467 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
468 if (!pred)
469 goto oom;
470 pred->fn = filter_pred_none;
471 filter->preds[i] = pred;
472 }
473
474 return 0;
475
476 oom:
477 destroy_preds(call);
478
479 return -ENOMEM;
480 }
481
482 static int init_subsystem_preds(struct event_subsystem *system)
483 {
484 struct ftrace_event_call *call;
485 int err;
486
487 list_for_each_entry(call, &ftrace_events, list) {
488 if (!call->define_fields)
489 continue;
490
491 if (strcmp(call->system, system->name) != 0)
492 continue;
493
494 err = init_preds(call);
495 if (err)
496 return err;
497 }
498
499 return 0;
500 }
501
502 enum {
503 FILTER_DISABLE_ALL,
504 FILTER_INIT_NO_RESET,
505 FILTER_SKIP_NO_RESET,
506 };
507
508 static void filter_free_subsystem_preds(struct event_subsystem *system,
509 int flag)
510 {
511 struct ftrace_event_call *call;
512
513 list_for_each_entry(call, &ftrace_events, list) {
514 if (!call->define_fields)
515 continue;
516
517 if (strcmp(call->system, system->name) != 0)
518 continue;
519
520 if (flag == FILTER_INIT_NO_RESET) {
521 call->filter->no_reset = false;
522 continue;
523 }
524
525 if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)
526 continue;
527
528 filter_disable_preds(call);
529 remove_filter_string(call->filter);
530 }
531 }
532
533 static int filter_add_pred_fn(struct filter_parse_state *ps,
534 struct ftrace_event_call *call,
535 struct filter_pred *pred,
536 filter_pred_fn_t fn)
537 {
538 struct event_filter *filter = call->filter;
539 int idx, err;
540
541 if (filter->n_preds == MAX_FILTER_PRED) {
542 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
543 return -ENOSPC;
544 }
545
546 idx = filter->n_preds;
547 filter_clear_pred(filter->preds[idx]);
548 err = filter_set_pred(filter->preds[idx], pred, fn);
549 if (err)
550 return err;
551
552 filter->n_preds++;
553 call->filter_active = 1;
554
555 return 0;
556 }
557
558 int filter_assign_type(const char *type)
559 {
560 if (strstr(type, "__data_loc") && strstr(type, "char"))
561 return FILTER_DYN_STRING;
562
563 if (strchr(type, '[') && strstr(type, "char"))
564 return FILTER_STATIC_STRING;
565
566 return FILTER_OTHER;
567 }
568
569 static bool is_string_field(struct ftrace_event_field *field)
570 {
571 return field->filter_type == FILTER_DYN_STRING ||
572 field->filter_type == FILTER_STATIC_STRING ||
573 field->filter_type == FILTER_PTR_STRING;
574 }
575
576 static int is_legal_op(struct ftrace_event_field *field, int op)
577 {
578 if (is_string_field(field) && (op != OP_EQ && op != OP_NE))
579 return 0;
580
581 return 1;
582 }
583
584 static filter_pred_fn_t select_comparison_fn(int op, int field_size,
585 int field_is_signed)
586 {
587 filter_pred_fn_t fn = NULL;
588
589 switch (field_size) {
590 case 8:
591 if (op == OP_EQ || op == OP_NE)
592 fn = filter_pred_64;
593 else if (field_is_signed)
594 fn = filter_pred_s64;
595 else
596 fn = filter_pred_u64;
597 break;
598 case 4:
599 if (op == OP_EQ || op == OP_NE)
600 fn = filter_pred_32;
601 else if (field_is_signed)
602 fn = filter_pred_s32;
603 else
604 fn = filter_pred_u32;
605 break;
606 case 2:
607 if (op == OP_EQ || op == OP_NE)
608 fn = filter_pred_16;
609 else if (field_is_signed)
610 fn = filter_pred_s16;
611 else
612 fn = filter_pred_u16;
613 break;
614 case 1:
615 if (op == OP_EQ || op == OP_NE)
616 fn = filter_pred_8;
617 else if (field_is_signed)
618 fn = filter_pred_s8;
619 else
620 fn = filter_pred_u8;
621 break;
622 }
623
624 return fn;
625 }
626
627 static int filter_add_pred(struct filter_parse_state *ps,
628 struct ftrace_event_call *call,
629 struct filter_pred *pred,
630 bool dry_run)
631 {
632 struct ftrace_event_field *field;
633 filter_pred_fn_t fn;
634 unsigned long long val;
635 int ret;
636
637 pred->fn = filter_pred_none;
638
639 if (pred->op == OP_AND) {
640 pred->pop_n = 2;
641 fn = filter_pred_and;
642 goto add_pred_fn;
643 } else if (pred->op == OP_OR) {
644 pred->pop_n = 2;
645 fn = filter_pred_or;
646 goto add_pred_fn;
647 }
648
649 field = find_event_field(call, pred->field_name);
650 if (!field) {
651 parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
652 return -EINVAL;
653 }
654
655 pred->offset = field->offset;
656
657 if (!is_legal_op(field, pred->op)) {
658 parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
659 return -EINVAL;
660 }
661
662 if (is_string_field(field)) {
663 pred->str_len = field->size;
664
665 if (field->filter_type == FILTER_STATIC_STRING)
666 fn = filter_pred_string;
667 else if (field->filter_type == FILTER_DYN_STRING)
668 fn = filter_pred_strloc;
669 else {
670 fn = filter_pred_pchar;
671 pred->str_len = strlen(pred->str_val);
672 }
673 } else {
674 if (field->is_signed)
675 ret = strict_strtoll(pred->str_val, 0, &val);
676 else
677 ret = strict_strtoull(pred->str_val, 0, &val);
678 if (ret) {
679 parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
680 return -EINVAL;
681 }
682 pred->val = val;
683
684 fn = select_comparison_fn(pred->op, field->size,
685 field->is_signed);
686 if (!fn) {
687 parse_error(ps, FILT_ERR_INVALID_OP, 0);
688 return -EINVAL;
689 }
690 }
691
692 if (pred->op == OP_NE)
693 pred->not = 1;
694
695 add_pred_fn:
696 if (!dry_run)
697 return filter_add_pred_fn(ps, call, pred, fn);
698 return 0;
699 }
700
701 static int filter_add_subsystem_pred(struct filter_parse_state *ps,
702 struct event_subsystem *system,
703 struct filter_pred *pred,
704 char *filter_string,
705 bool dry_run)
706 {
707 struct ftrace_event_call *call;
708 int err = 0;
709 bool fail = true;
710
711 list_for_each_entry(call, &ftrace_events, list) {
712
713 if (!call->define_fields)
714 continue;
715
716 if (strcmp(call->system, system->name))
717 continue;
718
719 if (call->filter->no_reset)
720 continue;
721
722 err = filter_add_pred(ps, call, pred, dry_run);
723 if (err)
724 call->filter->no_reset = true;
725 else
726 fail = false;
727
728 if (!dry_run)
729 replace_filter_string(call->filter, filter_string);
730 }
731
732 if (fail) {
733 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
734 return err;
735 }
736 return 0;
737 }
738
739 static void parse_init(struct filter_parse_state *ps,
740 struct filter_op *ops,
741 char *infix_string)
742 {
743 memset(ps, '\0', sizeof(*ps));
744
745 ps->infix.string = infix_string;
746 ps->infix.cnt = strlen(infix_string);
747 ps->ops = ops;
748
749 INIT_LIST_HEAD(&ps->opstack);
750 INIT_LIST_HEAD(&ps->postfix);
751 }
752
753 static char infix_next(struct filter_parse_state *ps)
754 {
755 ps->infix.cnt--;
756
757 return ps->infix.string[ps->infix.tail++];
758 }
759
760 static char infix_peek(struct filter_parse_state *ps)
761 {
762 if (ps->infix.tail == strlen(ps->infix.string))
763 return 0;
764
765 return ps->infix.string[ps->infix.tail];
766 }
767
768 static void infix_advance(struct filter_parse_state *ps)
769 {
770 ps->infix.cnt--;
771 ps->infix.tail++;
772 }
773
774 static inline int is_precedence_lower(struct filter_parse_state *ps,
775 int a, int b)
776 {
777 return ps->ops[a].precedence < ps->ops[b].precedence;
778 }
779
780 static inline int is_op_char(struct filter_parse_state *ps, char c)
781 {
782 int i;
783
784 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
785 if (ps->ops[i].string[0] == c)
786 return 1;
787 }
788
789 return 0;
790 }
791
792 static int infix_get_op(struct filter_parse_state *ps, char firstc)
793 {
794 char nextc = infix_peek(ps);
795 char opstr[3];
796 int i;
797
798 opstr[0] = firstc;
799 opstr[1] = nextc;
800 opstr[2] = '\0';
801
802 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
803 if (!strcmp(opstr, ps->ops[i].string)) {
804 infix_advance(ps);
805 return ps->ops[i].id;
806 }
807 }
808
809 opstr[1] = '\0';
810
811 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
812 if (!strcmp(opstr, ps->ops[i].string))
813 return ps->ops[i].id;
814 }
815
816 return OP_NONE;
817 }
818
819 static inline void clear_operand_string(struct filter_parse_state *ps)
820 {
821 memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
822 ps->operand.tail = 0;
823 }
824
825 static inline int append_operand_char(struct filter_parse_state *ps, char c)
826 {
827 if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
828 return -EINVAL;
829
830 ps->operand.string[ps->operand.tail++] = c;
831
832 return 0;
833 }
834
835 static int filter_opstack_push(struct filter_parse_state *ps, int op)
836 {
837 struct opstack_op *opstack_op;
838
839 opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
840 if (!opstack_op)
841 return -ENOMEM;
842
843 opstack_op->op = op;
844 list_add(&opstack_op->list, &ps->opstack);
845
846 return 0;
847 }
848
849 static int filter_opstack_empty(struct filter_parse_state *ps)
850 {
851 return list_empty(&ps->opstack);
852 }
853
854 static int filter_opstack_top(struct filter_parse_state *ps)
855 {
856 struct opstack_op *opstack_op;
857
858 if (filter_opstack_empty(ps))
859 return OP_NONE;
860
861 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
862
863 return opstack_op->op;
864 }
865
866 static int filter_opstack_pop(struct filter_parse_state *ps)
867 {
868 struct opstack_op *opstack_op;
869 int op;
870
871 if (filter_opstack_empty(ps))
872 return OP_NONE;
873
874 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
875 op = opstack_op->op;
876 list_del(&opstack_op->list);
877
878 kfree(opstack_op);
879
880 return op;
881 }
882
883 static void filter_opstack_clear(struct filter_parse_state *ps)
884 {
885 while (!filter_opstack_empty(ps))
886 filter_opstack_pop(ps);
887 }
888
889 static char *curr_operand(struct filter_parse_state *ps)
890 {
891 return ps->operand.string;
892 }
893
894 static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
895 {
896 struct postfix_elt *elt;
897
898 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
899 if (!elt)
900 return -ENOMEM;
901
902 elt->op = OP_NONE;
903 elt->operand = kstrdup(operand, GFP_KERNEL);
904 if (!elt->operand) {
905 kfree(elt);
906 return -ENOMEM;
907 }
908
909 list_add_tail(&elt->list, &ps->postfix);
910
911 return 0;
912 }
913
914 static int postfix_append_op(struct filter_parse_state *ps, int op)
915 {
916 struct postfix_elt *elt;
917
918 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
919 if (!elt)
920 return -ENOMEM;
921
922 elt->op = op;
923 elt->operand = NULL;
924
925 list_add_tail(&elt->list, &ps->postfix);
926
927 return 0;
928 }
929
930 static void postfix_clear(struct filter_parse_state *ps)
931 {
932 struct postfix_elt *elt;
933
934 while (!list_empty(&ps->postfix)) {
935 elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
936 kfree(elt->operand);
937 list_del(&elt->list);
938 }
939 }
940
941 static int filter_parse(struct filter_parse_state *ps)
942 {
943 int in_string = 0;
944 int op, top_op;
945 char ch;
946
947 while ((ch = infix_next(ps))) {
948 if (ch == '"') {
949 in_string ^= 1;
950 continue;
951 }
952
953 if (in_string)
954 goto parse_operand;
955
956 if (isspace(ch))
957 continue;
958
959 if (is_op_char(ps, ch)) {
960 op = infix_get_op(ps, ch);
961 if (op == OP_NONE) {
962 parse_error(ps, FILT_ERR_INVALID_OP, 0);
963 return -EINVAL;
964 }
965
966 if (strlen(curr_operand(ps))) {
967 postfix_append_operand(ps, curr_operand(ps));
968 clear_operand_string(ps);
969 }
970
971 while (!filter_opstack_empty(ps)) {
972 top_op = filter_opstack_top(ps);
973 if (!is_precedence_lower(ps, top_op, op)) {
974 top_op = filter_opstack_pop(ps);
975 postfix_append_op(ps, top_op);
976 continue;
977 }
978 break;
979 }
980
981 filter_opstack_push(ps, op);
982 continue;
983 }
984
985 if (ch == '(') {
986 filter_opstack_push(ps, OP_OPEN_PAREN);
987 continue;
988 }
989
990 if (ch == ')') {
991 if (strlen(curr_operand(ps))) {
992 postfix_append_operand(ps, curr_operand(ps));
993 clear_operand_string(ps);
994 }
995
996 top_op = filter_opstack_pop(ps);
997 while (top_op != OP_NONE) {
998 if (top_op == OP_OPEN_PAREN)
999 break;
1000 postfix_append_op(ps, top_op);
1001 top_op = filter_opstack_pop(ps);
1002 }
1003 if (top_op == OP_NONE) {
1004 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1005 return -EINVAL;
1006 }
1007 continue;
1008 }
1009 parse_operand:
1010 if (append_operand_char(ps, ch)) {
1011 parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
1012 return -EINVAL;
1013 }
1014 }
1015
1016 if (strlen(curr_operand(ps)))
1017 postfix_append_operand(ps, curr_operand(ps));
1018
1019 while (!filter_opstack_empty(ps)) {
1020 top_op = filter_opstack_pop(ps);
1021 if (top_op == OP_NONE)
1022 break;
1023 if (top_op == OP_OPEN_PAREN) {
1024 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1025 return -EINVAL;
1026 }
1027 postfix_append_op(ps, top_op);
1028 }
1029
1030 return 0;
1031 }
1032
1033 static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
1034 {
1035 struct filter_pred *pred;
1036
1037 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
1038 if (!pred)
1039 return NULL;
1040
1041 pred->field_name = kstrdup(operand1, GFP_KERNEL);
1042 if (!pred->field_name) {
1043 kfree(pred);
1044 return NULL;
1045 }
1046
1047 strcpy(pred->str_val, operand2);
1048 pred->str_len = strlen(operand2);
1049
1050 pred->op = op;
1051
1052 return pred;
1053 }
1054
1055 static struct filter_pred *create_logical_pred(int op)
1056 {
1057 struct filter_pred *pred;
1058
1059 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
1060 if (!pred)
1061 return NULL;
1062
1063 pred->op = op;
1064
1065 return pred;
1066 }
1067
1068 static int check_preds(struct filter_parse_state *ps)
1069 {
1070 int n_normal_preds = 0, n_logical_preds = 0;
1071 struct postfix_elt *elt;
1072
1073 list_for_each_entry(elt, &ps->postfix, list) {
1074 if (elt->op == OP_NONE)
1075 continue;
1076
1077 if (elt->op == OP_AND || elt->op == OP_OR) {
1078 n_logical_preds++;
1079 continue;
1080 }
1081 n_normal_preds++;
1082 }
1083
1084 if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
1085 parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
1086 return -EINVAL;
1087 }
1088
1089 return 0;
1090 }
1091
1092 static int replace_preds(struct event_subsystem *system,
1093 struct ftrace_event_call *call,
1094 struct filter_parse_state *ps,
1095 char *filter_string,
1096 bool dry_run)
1097 {
1098 char *operand1 = NULL, *operand2 = NULL;
1099 struct filter_pred *pred;
1100 struct postfix_elt *elt;
1101 int err;
1102 int n_preds = 0;
1103
1104 err = check_preds(ps);
1105 if (err)
1106 return err;
1107
1108 list_for_each_entry(elt, &ps->postfix, list) {
1109 if (elt->op == OP_NONE) {
1110 if (!operand1)
1111 operand1 = elt->operand;
1112 else if (!operand2)
1113 operand2 = elt->operand;
1114 else {
1115 parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
1116 return -EINVAL;
1117 }
1118 continue;
1119 }
1120
1121 if (n_preds++ == MAX_FILTER_PRED) {
1122 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1123 return -ENOSPC;
1124 }
1125
1126 if (elt->op == OP_AND || elt->op == OP_OR) {
1127 pred = create_logical_pred(elt->op);
1128 goto add_pred;
1129 }
1130
1131 if (!operand1 || !operand2) {
1132 parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
1133 return -EINVAL;
1134 }
1135
1136 pred = create_pred(elt->op, operand1, operand2);
1137 add_pred:
1138 if (!pred)
1139 return -ENOMEM;
1140 if (call)
1141 err = filter_add_pred(ps, call, pred, false);
1142 else
1143 err = filter_add_subsystem_pred(ps, system, pred,
1144 filter_string, dry_run);
1145 filter_free_pred(pred);
1146 if (err)
1147 return err;
1148
1149 operand1 = operand2 = NULL;
1150 }
1151
1152 return 0;
1153 }
1154
1155 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
1156 {
1157 int err;
1158
1159 struct filter_parse_state *ps;
1160
1161 mutex_lock(&event_mutex);
1162
1163 err = init_preds(call);
1164 if (err)
1165 goto out_unlock;
1166
1167 if (!strcmp(strstrip(filter_string), "0")) {
1168 filter_disable_preds(call);
1169 remove_filter_string(call->filter);
1170 mutex_unlock(&event_mutex);
1171 return 0;
1172 }
1173
1174 err = -ENOMEM;
1175 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1176 if (!ps)
1177 goto out_unlock;
1178
1179 filter_disable_preds(call);
1180 replace_filter_string(call->filter, filter_string);
1181
1182 parse_init(ps, filter_ops, filter_string);
1183 err = filter_parse(ps);
1184 if (err) {
1185 append_filter_err(ps, call->filter);
1186 goto out;
1187 }
1188
1189 err = replace_preds(NULL, call, ps, filter_string, false);
1190 if (err)
1191 append_filter_err(ps, call->filter);
1192
1193 out:
1194 filter_opstack_clear(ps);
1195 postfix_clear(ps);
1196 kfree(ps);
1197 out_unlock:
1198 mutex_unlock(&event_mutex);
1199
1200 return err;
1201 }
1202
1203 int apply_subsystem_event_filter(struct event_subsystem *system,
1204 char *filter_string)
1205 {
1206 int err;
1207
1208 struct filter_parse_state *ps;
1209
1210 mutex_lock(&event_mutex);
1211
1212 err = init_subsystem_preds(system);
1213 if (err)
1214 goto out_unlock;
1215
1216 if (!strcmp(strstrip(filter_string), "0")) {
1217 filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);
1218 remove_filter_string(system->filter);
1219 mutex_unlock(&event_mutex);
1220 return 0;
1221 }
1222
1223 err = -ENOMEM;
1224 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1225 if (!ps)
1226 goto out_unlock;
1227
1228 replace_filter_string(system->filter, filter_string);
1229
1230 parse_init(ps, filter_ops, filter_string);
1231 err = filter_parse(ps);
1232 if (err) {
1233 append_filter_err(ps, system->filter);
1234 goto out;
1235 }
1236
1237 filter_free_subsystem_preds(system, FILTER_INIT_NO_RESET);
1238
1239 /* try to see the filter can be applied to which events */
1240 err = replace_preds(system, NULL, ps, filter_string, true);
1241 if (err) {
1242 append_filter_err(ps, system->filter);
1243 goto out;
1244 }
1245
1246 filter_free_subsystem_preds(system, FILTER_SKIP_NO_RESET);
1247
1248 /* really apply the filter to the events */
1249 err = replace_preds(system, NULL, ps, filter_string, false);
1250 if (err) {
1251 append_filter_err(ps, system->filter);
1252 filter_free_subsystem_preds(system, 2);
1253 }
1254
1255 out:
1256 filter_opstack_clear(ps);
1257 postfix_clear(ps);
1258 kfree(ps);
1259 out_unlock:
1260 mutex_unlock(&event_mutex);
1261
1262 return err;
1263 }
1264
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