2 * trace_events_filter - generic event filtering
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.
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.
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.
18 * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
21 #include <linux/module.h>
22 #include <linux/ctype.h>
23 #include <linux/mutex.h>
24 #include <linux/perf_event.h>
25 #include <linux/slab.h>
28 #include "trace_output.h"
51 static struct filter_op filter_ops[] = {
61 { OP_NONE, "OP_NONE", 0 },
62 { OP_OPEN_PAREN, "(", 0 },
68 FILT_ERR_UNBALANCED_PAREN,
69 FILT_ERR_TOO_MANY_OPERANDS,
70 FILT_ERR_OPERAND_TOO_LONG,
71 FILT_ERR_FIELD_NOT_FOUND,
72 FILT_ERR_ILLEGAL_FIELD_OP,
73 FILT_ERR_ILLEGAL_INTVAL,
74 FILT_ERR_BAD_SUBSYS_FILTER,
75 FILT_ERR_TOO_MANY_PREDS,
76 FILT_ERR_MISSING_FIELD,
77 FILT_ERR_INVALID_FILTER,
80 static char *err_text[] = {
87 "Illegal operation for field type",
88 "Illegal integer value",
89 "Couldn't find or set field in one of a subsystem's events",
90 "Too many terms in predicate expression",
91 "Missing field name and/or value",
92 "Meaningless filter expression",
97 struct list_head list;
103 struct list_head list;
106 struct filter_parse_state {
107 struct filter_op *ops;
108 struct list_head opstack;
109 struct list_head postfix;
120 char string[MAX_FILTER_STR_VAL];
127 struct filter_pred **preds;
131 #define DEFINE_COMPARISON_PRED(type) \
132 static int filter_pred_##type(struct filter_pred *pred, void *event) \
134 type *addr = (type *)(event + pred->offset); \
135 type val = (type)pred->val; \
138 switch (pred->op) { \
140 match = (*addr < val); \
143 match = (*addr <= val); \
146 match = (*addr > val); \
149 match = (*addr >= val); \
158 #define DEFINE_EQUALITY_PRED(size) \
159 static int filter_pred_##size(struct filter_pred *pred, void *event) \
161 u##size *addr = (u##size *)(event + pred->offset); \
162 u##size val = (u##size)pred->val; \
165 match = (val == *addr) ^ pred->not; \
170 DEFINE_COMPARISON_PRED(s64);
171 DEFINE_COMPARISON_PRED(u64);
172 DEFINE_COMPARISON_PRED(s32);
173 DEFINE_COMPARISON_PRED(u32);
174 DEFINE_COMPARISON_PRED(s16);
175 DEFINE_COMPARISON_PRED(u16);
176 DEFINE_COMPARISON_PRED(s8);
177 DEFINE_COMPARISON_PRED(u8);
179 DEFINE_EQUALITY_PRED(64);
180 DEFINE_EQUALITY_PRED(32);
181 DEFINE_EQUALITY_PRED(16);
182 DEFINE_EQUALITY_PRED(8);
184 /* Filter predicate for fixed sized arrays of characters */
185 static int filter_pred_string(struct filter_pred *pred, void *event)
187 char *addr = (char *)(event + pred->offset);
190 cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
192 match = cmp ^ pred->not;
197 /* Filter predicate for char * pointers */
198 static int filter_pred_pchar(struct filter_pred *pred, void *event)
200 char **addr = (char **)(event + pred->offset);
202 int len = strlen(*addr) + 1; /* including tailing '\0' */
204 cmp = pred->regex.match(*addr, &pred->regex, len);
206 match = cmp ^ pred->not;
212 * Filter predicate for dynamic sized arrays of characters.
213 * These are implemented through a list of strings at the end
215 * Also each of these strings have a field in the entry which
216 * contains its offset from the beginning of the entry.
217 * We have then first to get this field, dereference it
218 * and add it to the address of the entry, and at last we have
219 * the address of the string.
221 static int filter_pred_strloc(struct filter_pred *pred, void *event)
223 u32 str_item = *(u32 *)(event + pred->offset);
224 int str_loc = str_item & 0xffff;
225 int str_len = str_item >> 16;
226 char *addr = (char *)(event + str_loc);
229 cmp = pred->regex.match(addr, &pred->regex, str_len);
231 match = cmp ^ pred->not;
236 static int filter_pred_none(struct filter_pred *pred, void *event)
242 * regex_match_foo - Basic regex callbacks
244 * @str: the string to be searched
245 * @r: the regex structure containing the pattern string
246 * @len: the length of the string to be searched (including '\0')
249 * - @str might not be NULL-terminated if it's of type DYN_STRING
253 static int regex_match_full(char *str, struct regex *r, int len)
255 if (strncmp(str, r->pattern, len) == 0)
260 static int regex_match_front(char *str, struct regex *r, int len)
262 if (strncmp(str, r->pattern, r->len) == 0)
267 static int regex_match_middle(char *str, struct regex *r, int len)
269 if (strnstr(str, r->pattern, len))
274 static int regex_match_end(char *str, struct regex *r, int len)
276 int strlen = len - 1;
278 if (strlen >= r->len &&
279 memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
285 * filter_parse_regex - parse a basic regex
286 * @buff: the raw regex
287 * @len: length of the regex
288 * @search: will point to the beginning of the string to compare
289 * @not: tell whether the match will have to be inverted
291 * This passes in a buffer containing a regex and this function will
292 * set search to point to the search part of the buffer and
293 * return the type of search it is (see enum above).
294 * This does modify buff.
297 * search returns the pointer to use for comparison.
298 * not returns 1 if buff started with a '!'
301 enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
303 int type = MATCH_FULL;
306 if (buff[0] == '!') {
315 for (i = 0; i < len; i++) {
316 if (buff[i] == '*') {
319 type = MATCH_END_ONLY;
321 if (type == MATCH_END_ONLY)
322 type = MATCH_MIDDLE_ONLY;
324 type = MATCH_FRONT_ONLY;
334 static void filter_build_regex(struct filter_pred *pred)
336 struct regex *r = &pred->regex;
338 enum regex_type type = MATCH_FULL;
341 if (pred->op == OP_GLOB) {
342 type = filter_parse_regex(r->pattern, r->len, &search, ¬);
343 r->len = strlen(search);
344 memmove(r->pattern, search, r->len+1);
349 r->match = regex_match_full;
351 case MATCH_FRONT_ONLY:
352 r->match = regex_match_front;
354 case MATCH_MIDDLE_ONLY:
355 r->match = regex_match_middle;
358 r->match = regex_match_end;
371 static struct filter_pred *
372 get_pred_parent(struct filter_pred *pred, struct filter_pred *preds,
373 int index, enum move_type *move)
375 if (pred->parent & FILTER_PRED_IS_RIGHT)
376 *move = MOVE_UP_FROM_RIGHT;
378 *move = MOVE_UP_FROM_LEFT;
379 pred = &preds[pred->parent & ~FILTER_PRED_IS_RIGHT];
390 typedef int (*filter_pred_walkcb_t) (enum move_type move,
391 struct filter_pred *pred,
392 int *err, void *data);
394 static int walk_pred_tree(struct filter_pred *preds,
395 struct filter_pred *root,
396 filter_pred_walkcb_t cb, void *data)
398 struct filter_pred *pred = root;
399 enum move_type move = MOVE_DOWN;
408 ret = cb(move, pred, &err, data);
409 if (ret == WALK_PRED_ABORT)
411 if (ret == WALK_PRED_PARENT)
416 if (pred->left != FILTER_PRED_INVALID) {
417 pred = &preds[pred->left];
421 case MOVE_UP_FROM_LEFT:
422 pred = &preds[pred->right];
425 case MOVE_UP_FROM_RIGHT:
429 pred = get_pred_parent(pred, preds,
442 * A series of AND or ORs where found together. Instead of
443 * climbing up and down the tree branches, an array of the
444 * ops were made in order of checks. We can just move across
445 * the array and short circuit if needed.
447 static int process_ops(struct filter_pred *preds,
448 struct filter_pred *op, void *rec)
450 struct filter_pred *pred;
456 * Micro-optimization: We set type to true if op
457 * is an OR and false otherwise (AND). Then we
458 * just need to test if the match is equal to
459 * the type, and if it is, we can short circuit the
460 * rest of the checks:
462 * if ((match && op->op == OP_OR) ||
463 * (!match && op->op == OP_AND))
466 type = op->op == OP_OR;
468 for (i = 0; i < op->val; i++) {
469 pred = &preds[op->ops[i]];
470 if (!WARN_ON_ONCE(!pred->fn))
471 match = pred->fn(pred, rec);
478 struct filter_match_preds_data {
479 struct filter_pred *preds;
484 static int filter_match_preds_cb(enum move_type move, struct filter_pred *pred,
485 int *err, void *data)
487 struct filter_match_preds_data *d = data;
492 /* only AND and OR have children */
493 if (pred->left != FILTER_PRED_INVALID) {
494 /* If ops is set, then it was folded. */
496 return WALK_PRED_DEFAULT;
497 /* We can treat folded ops as a leaf node */
498 d->match = process_ops(d->preds, pred, d->rec);
500 if (!WARN_ON_ONCE(!pred->fn))
501 d->match = pred->fn(pred, d->rec);
504 return WALK_PRED_PARENT;
505 case MOVE_UP_FROM_LEFT:
507 * Check for short circuits.
509 * Optimization: !!match == (pred->op == OP_OR)
511 * if ((match && pred->op == OP_OR) ||
512 * (!match && pred->op == OP_AND))
514 if (!!d->match == (pred->op == OP_OR))
515 return WALK_PRED_PARENT;
517 case MOVE_UP_FROM_RIGHT:
521 return WALK_PRED_DEFAULT;
524 /* return 1 if event matches, 0 otherwise (discard) */
525 int filter_match_preds(struct event_filter *filter, void *rec)
527 struct filter_pred *preds;
528 struct filter_pred *root;
529 struct filter_match_preds_data data = {
530 /* match is currently meaningless */
536 /* no filter is considered a match */
540 n_preds = filter->n_preds;
545 * n_preds, root and filter->preds are protect with preemption disabled.
547 root = rcu_dereference_sched(filter->root);
551 data.preds = preds = rcu_dereference_sched(filter->preds);
552 ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data);
556 EXPORT_SYMBOL_GPL(filter_match_preds);
558 static void parse_error(struct filter_parse_state *ps, int err, int pos)
561 ps->lasterr_pos = pos;
564 static void remove_filter_string(struct event_filter *filter)
569 kfree(filter->filter_string);
570 filter->filter_string = NULL;
573 static int replace_filter_string(struct event_filter *filter,
576 kfree(filter->filter_string);
577 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
578 if (!filter->filter_string)
584 static int append_filter_string(struct event_filter *filter,
588 char *new_filter_string;
590 BUG_ON(!filter->filter_string);
591 newlen = strlen(filter->filter_string) + strlen(string) + 1;
592 new_filter_string = kmalloc(newlen, GFP_KERNEL);
593 if (!new_filter_string)
596 strcpy(new_filter_string, filter->filter_string);
597 strcat(new_filter_string, string);
598 kfree(filter->filter_string);
599 filter->filter_string = new_filter_string;
604 static void append_filter_err(struct filter_parse_state *ps,
605 struct event_filter *filter)
607 int pos = ps->lasterr_pos;
610 buf = (char *)__get_free_page(GFP_TEMPORARY);
614 append_filter_string(filter, "\n");
615 memset(buf, ' ', PAGE_SIZE);
616 if (pos > PAGE_SIZE - 128)
619 pbuf = &buf[pos] + 1;
621 sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
622 append_filter_string(filter, buf);
623 free_page((unsigned long) buf);
626 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
628 struct event_filter *filter;
630 mutex_lock(&event_mutex);
631 filter = call->filter;
632 if (filter && filter->filter_string)
633 trace_seq_printf(s, "%s\n", filter->filter_string);
635 trace_seq_printf(s, "none\n");
636 mutex_unlock(&event_mutex);
639 void print_subsystem_event_filter(struct event_subsystem *system,
642 struct event_filter *filter;
644 mutex_lock(&event_mutex);
645 filter = system->filter;
646 if (filter && filter->filter_string)
647 trace_seq_printf(s, "%s\n", filter->filter_string);
649 trace_seq_printf(s, "none\n");
650 mutex_unlock(&event_mutex);
653 static struct ftrace_event_field *
654 __find_event_field(struct list_head *head, char *name)
656 struct ftrace_event_field *field;
658 list_for_each_entry(field, head, link) {
659 if (!strcmp(field->name, name))
666 static struct ftrace_event_field *
667 find_event_field(struct ftrace_event_call *call, char *name)
669 struct ftrace_event_field *field;
670 struct list_head *head;
672 field = __find_event_field(&ftrace_common_fields, name);
676 head = trace_get_fields(call);
677 return __find_event_field(head, name);
680 static int __alloc_pred_stack(struct pred_stack *stack, int n_preds)
682 stack->preds = kzalloc(sizeof(*stack->preds)*(n_preds + 1), GFP_KERNEL);
685 stack->index = n_preds;
689 static void __free_pred_stack(struct pred_stack *stack)
695 static int __push_pred_stack(struct pred_stack *stack,
696 struct filter_pred *pred)
698 int index = stack->index;
700 if (WARN_ON(index == 0))
703 stack->preds[--index] = pred;
704 stack->index = index;
708 static struct filter_pred *
709 __pop_pred_stack(struct pred_stack *stack)
711 struct filter_pred *pred;
712 int index = stack->index;
714 pred = stack->preds[index++];
718 stack->index = index;
722 static int filter_set_pred(struct event_filter *filter,
724 struct pred_stack *stack,
725 struct filter_pred *src)
727 struct filter_pred *dest = &filter->preds[idx];
728 struct filter_pred *left;
729 struct filter_pred *right;
734 if (dest->op == OP_OR || dest->op == OP_AND) {
735 right = __pop_pred_stack(stack);
736 left = __pop_pred_stack(stack);
740 * If both children can be folded
741 * and they are the same op as this op or a leaf,
742 * then this op can be folded.
744 if (left->index & FILTER_PRED_FOLD &&
745 (left->op == dest->op ||
746 left->left == FILTER_PRED_INVALID) &&
747 right->index & FILTER_PRED_FOLD &&
748 (right->op == dest->op ||
749 right->left == FILTER_PRED_INVALID))
750 dest->index |= FILTER_PRED_FOLD;
752 dest->left = left->index & ~FILTER_PRED_FOLD;
753 dest->right = right->index & ~FILTER_PRED_FOLD;
754 left->parent = dest->index & ~FILTER_PRED_FOLD;
755 right->parent = dest->index | FILTER_PRED_IS_RIGHT;
758 * Make dest->left invalid to be used as a quick
759 * way to know this is a leaf node.
761 dest->left = FILTER_PRED_INVALID;
763 /* All leafs allow folding the parent ops. */
764 dest->index |= FILTER_PRED_FOLD;
767 return __push_pred_stack(stack, dest);
770 static void __free_preds(struct event_filter *filter)
773 kfree(filter->preds);
774 filter->preds = NULL;
780 static void filter_disable(struct ftrace_event_call *call)
782 call->flags &= ~TRACE_EVENT_FL_FILTERED;
785 static void __free_filter(struct event_filter *filter)
790 __free_preds(filter);
791 kfree(filter->filter_string);
796 * Called when destroying the ftrace_event_call.
797 * The call is being freed, so we do not need to worry about
798 * the call being currently used. This is for module code removing
799 * the tracepoints from within it.
801 void destroy_preds(struct ftrace_event_call *call)
803 __free_filter(call->filter);
807 static struct event_filter *__alloc_filter(void)
809 struct event_filter *filter;
811 filter = kzalloc(sizeof(*filter), GFP_KERNEL);
815 static int __alloc_preds(struct event_filter *filter, int n_preds)
817 struct filter_pred *pred;
821 __free_preds(filter);
824 kzalloc(sizeof(*filter->preds) * n_preds, GFP_KERNEL);
829 filter->a_preds = n_preds;
832 for (i = 0; i < n_preds; i++) {
833 pred = &filter->preds[i];
834 pred->fn = filter_pred_none;
840 static void filter_free_subsystem_preds(struct event_subsystem *system)
842 struct ftrace_event_call *call;
844 list_for_each_entry(call, &ftrace_events, list) {
845 if (strcmp(call->class->system, system->name) != 0)
848 filter_disable(call);
849 remove_filter_string(call->filter);
853 static void filter_free_subsystem_filters(struct event_subsystem *system)
855 struct ftrace_event_call *call;
857 list_for_each_entry(call, &ftrace_events, list) {
858 if (strcmp(call->class->system, system->name) != 0)
860 __free_filter(call->filter);
865 static int filter_add_pred(struct filter_parse_state *ps,
866 struct event_filter *filter,
867 struct filter_pred *pred,
868 struct pred_stack *stack)
872 if (WARN_ON(filter->n_preds == filter->a_preds)) {
873 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
877 err = filter_set_pred(filter, filter->n_preds, stack, pred);
886 int filter_assign_type(const char *type)
888 if (strstr(type, "__data_loc") && strstr(type, "char"))
889 return FILTER_DYN_STRING;
891 if (strchr(type, '[') && strstr(type, "char"))
892 return FILTER_STATIC_STRING;
897 static bool is_string_field(struct ftrace_event_field *field)
899 return field->filter_type == FILTER_DYN_STRING ||
900 field->filter_type == FILTER_STATIC_STRING ||
901 field->filter_type == FILTER_PTR_STRING;
904 static int is_legal_op(struct ftrace_event_field *field, int op)
906 if (is_string_field(field) &&
907 (op != OP_EQ && op != OP_NE && op != OP_GLOB))
909 if (!is_string_field(field) && op == OP_GLOB)
915 static filter_pred_fn_t select_comparison_fn(int op, int field_size,
918 filter_pred_fn_t fn = NULL;
920 switch (field_size) {
922 if (op == OP_EQ || op == OP_NE)
924 else if (field_is_signed)
925 fn = filter_pred_s64;
927 fn = filter_pred_u64;
930 if (op == OP_EQ || op == OP_NE)
932 else if (field_is_signed)
933 fn = filter_pred_s32;
935 fn = filter_pred_u32;
938 if (op == OP_EQ || op == OP_NE)
940 else if (field_is_signed)
941 fn = filter_pred_s16;
943 fn = filter_pred_u16;
946 if (op == OP_EQ || op == OP_NE)
948 else if (field_is_signed)
958 static int init_pred(struct filter_parse_state *ps,
959 struct ftrace_event_field *field,
960 struct filter_pred *pred)
963 filter_pred_fn_t fn = filter_pred_none;
964 unsigned long long val;
967 pred->offset = field->offset;
969 if (!is_legal_op(field, pred->op)) {
970 parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
974 if (is_string_field(field)) {
975 filter_build_regex(pred);
977 if (field->filter_type == FILTER_STATIC_STRING) {
978 fn = filter_pred_string;
979 pred->regex.field_len = field->size;
980 } else if (field->filter_type == FILTER_DYN_STRING)
981 fn = filter_pred_strloc;
983 fn = filter_pred_pchar;
985 if (field->is_signed)
986 ret = strict_strtoll(pred->regex.pattern, 0, &val);
988 ret = strict_strtoull(pred->regex.pattern, 0, &val);
990 parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
995 fn = select_comparison_fn(pred->op, field->size,
998 parse_error(ps, FILT_ERR_INVALID_OP, 0);
1003 if (pred->op == OP_NE)
1010 static void parse_init(struct filter_parse_state *ps,
1011 struct filter_op *ops,
1014 memset(ps, '\0', sizeof(*ps));
1016 ps->infix.string = infix_string;
1017 ps->infix.cnt = strlen(infix_string);
1020 INIT_LIST_HEAD(&ps->opstack);
1021 INIT_LIST_HEAD(&ps->postfix);
1024 static char infix_next(struct filter_parse_state *ps)
1028 return ps->infix.string[ps->infix.tail++];
1031 static char infix_peek(struct filter_parse_state *ps)
1033 if (ps->infix.tail == strlen(ps->infix.string))
1036 return ps->infix.string[ps->infix.tail];
1039 static void infix_advance(struct filter_parse_state *ps)
1045 static inline int is_precedence_lower(struct filter_parse_state *ps,
1048 return ps->ops[a].precedence < ps->ops[b].precedence;
1051 static inline int is_op_char(struct filter_parse_state *ps, char c)
1055 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1056 if (ps->ops[i].string[0] == c)
1063 static int infix_get_op(struct filter_parse_state *ps, char firstc)
1065 char nextc = infix_peek(ps);
1073 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1074 if (!strcmp(opstr, ps->ops[i].string)) {
1076 return ps->ops[i].id;
1082 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
1083 if (!strcmp(opstr, ps->ops[i].string))
1084 return ps->ops[i].id;
1090 static inline void clear_operand_string(struct filter_parse_state *ps)
1092 memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
1093 ps->operand.tail = 0;
1096 static inline int append_operand_char(struct filter_parse_state *ps, char c)
1098 if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
1101 ps->operand.string[ps->operand.tail++] = c;
1106 static int filter_opstack_push(struct filter_parse_state *ps, int op)
1108 struct opstack_op *opstack_op;
1110 opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
1114 opstack_op->op = op;
1115 list_add(&opstack_op->list, &ps->opstack);
1120 static int filter_opstack_empty(struct filter_parse_state *ps)
1122 return list_empty(&ps->opstack);
1125 static int filter_opstack_top(struct filter_parse_state *ps)
1127 struct opstack_op *opstack_op;
1129 if (filter_opstack_empty(ps))
1132 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
1134 return opstack_op->op;
1137 static int filter_opstack_pop(struct filter_parse_state *ps)
1139 struct opstack_op *opstack_op;
1142 if (filter_opstack_empty(ps))
1145 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
1146 op = opstack_op->op;
1147 list_del(&opstack_op->list);
1154 static void filter_opstack_clear(struct filter_parse_state *ps)
1156 while (!filter_opstack_empty(ps))
1157 filter_opstack_pop(ps);
1160 static char *curr_operand(struct filter_parse_state *ps)
1162 return ps->operand.string;
1165 static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
1167 struct postfix_elt *elt;
1169 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
1174 elt->operand = kstrdup(operand, GFP_KERNEL);
1175 if (!elt->operand) {
1180 list_add_tail(&elt->list, &ps->postfix);
1185 static int postfix_append_op(struct filter_parse_state *ps, int op)
1187 struct postfix_elt *elt;
1189 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
1194 elt->operand = NULL;
1196 list_add_tail(&elt->list, &ps->postfix);
1201 static void postfix_clear(struct filter_parse_state *ps)
1203 struct postfix_elt *elt;
1205 while (!list_empty(&ps->postfix)) {
1206 elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
1207 list_del(&elt->list);
1208 kfree(elt->operand);
1213 static int filter_parse(struct filter_parse_state *ps)
1219 while ((ch = infix_next(ps))) {
1231 if (is_op_char(ps, ch)) {
1232 op = infix_get_op(ps, ch);
1233 if (op == OP_NONE) {
1234 parse_error(ps, FILT_ERR_INVALID_OP, 0);
1238 if (strlen(curr_operand(ps))) {
1239 postfix_append_operand(ps, curr_operand(ps));
1240 clear_operand_string(ps);
1243 while (!filter_opstack_empty(ps)) {
1244 top_op = filter_opstack_top(ps);
1245 if (!is_precedence_lower(ps, top_op, op)) {
1246 top_op = filter_opstack_pop(ps);
1247 postfix_append_op(ps, top_op);
1253 filter_opstack_push(ps, op);
1258 filter_opstack_push(ps, OP_OPEN_PAREN);
1263 if (strlen(curr_operand(ps))) {
1264 postfix_append_operand(ps, curr_operand(ps));
1265 clear_operand_string(ps);
1268 top_op = filter_opstack_pop(ps);
1269 while (top_op != OP_NONE) {
1270 if (top_op == OP_OPEN_PAREN)
1272 postfix_append_op(ps, top_op);
1273 top_op = filter_opstack_pop(ps);
1275 if (top_op == OP_NONE) {
1276 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1282 if (append_operand_char(ps, ch)) {
1283 parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
1288 if (strlen(curr_operand(ps)))
1289 postfix_append_operand(ps, curr_operand(ps));
1291 while (!filter_opstack_empty(ps)) {
1292 top_op = filter_opstack_pop(ps);
1293 if (top_op == OP_NONE)
1295 if (top_op == OP_OPEN_PAREN) {
1296 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
1299 postfix_append_op(ps, top_op);
1305 static struct filter_pred *create_pred(struct filter_parse_state *ps,
1306 struct ftrace_event_call *call,
1307 int op, char *operand1, char *operand2)
1309 struct ftrace_event_field *field;
1310 static struct filter_pred pred;
1312 memset(&pred, 0, sizeof(pred));
1315 if (op == OP_AND || op == OP_OR)
1318 if (!operand1 || !operand2) {
1319 parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
1323 field = find_event_field(call, operand1);
1325 parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
1329 strcpy(pred.regex.pattern, operand2);
1330 pred.regex.len = strlen(pred.regex.pattern);
1332 #ifdef CONFIG_FTRACE_STARTUP_TEST
1335 return init_pred(ps, field, &pred) ? NULL : &pred;
1338 static int check_preds(struct filter_parse_state *ps)
1340 int n_normal_preds = 0, n_logical_preds = 0;
1341 struct postfix_elt *elt;
1343 list_for_each_entry(elt, &ps->postfix, list) {
1344 if (elt->op == OP_NONE)
1347 if (elt->op == OP_AND || elt->op == OP_OR) {
1354 if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
1355 parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
1362 static int count_preds(struct filter_parse_state *ps)
1364 struct postfix_elt *elt;
1367 list_for_each_entry(elt, &ps->postfix, list) {
1368 if (elt->op == OP_NONE)
1376 struct check_pred_data {
1381 static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred,
1382 int *err, void *data)
1384 struct check_pred_data *d = data;
1386 if (WARN_ON(d->count++ > d->max)) {
1388 return WALK_PRED_ABORT;
1390 return WALK_PRED_DEFAULT;
1394 * The tree is walked at filtering of an event. If the tree is not correctly
1395 * built, it may cause an infinite loop. Check here that the tree does
1398 static int check_pred_tree(struct event_filter *filter,
1399 struct filter_pred *root)
1401 struct check_pred_data data = {
1403 * The max that we can hit a node is three times.
1404 * Once going down, once coming up from left, and
1405 * once coming up from right. This is more than enough
1406 * since leafs are only hit a single time.
1408 .max = 3 * filter->n_preds,
1412 return walk_pred_tree(filter->preds, root,
1413 check_pred_tree_cb, &data);
1416 static int count_leafs_cb(enum move_type move, struct filter_pred *pred,
1417 int *err, void *data)
1421 if ((move == MOVE_DOWN) &&
1422 (pred->left == FILTER_PRED_INVALID))
1425 return WALK_PRED_DEFAULT;
1428 static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
1432 ret = walk_pred_tree(preds, root, count_leafs_cb, &count);
1437 struct fold_pred_data {
1438 struct filter_pred *root;
1443 static int fold_pred_cb(enum move_type move, struct filter_pred *pred,
1444 int *err, void *data)
1446 struct fold_pred_data *d = data;
1447 struct filter_pred *root = d->root;
1449 if (move != MOVE_DOWN)
1450 return WALK_PRED_DEFAULT;
1451 if (pred->left != FILTER_PRED_INVALID)
1452 return WALK_PRED_DEFAULT;
1454 if (WARN_ON(d->count == d->children)) {
1456 return WALK_PRED_ABORT;
1459 pred->index &= ~FILTER_PRED_FOLD;
1460 root->ops[d->count++] = pred->index;
1461 return WALK_PRED_DEFAULT;
1464 static int fold_pred(struct filter_pred *preds, struct filter_pred *root)
1466 struct fold_pred_data data = {
1472 /* No need to keep the fold flag */
1473 root->index &= ~FILTER_PRED_FOLD;
1475 /* If the root is a leaf then do nothing */
1476 if (root->left == FILTER_PRED_INVALID)
1479 /* count the children */
1480 children = count_leafs(preds, &preds[root->left]);
1481 children += count_leafs(preds, &preds[root->right]);
1483 root->ops = kzalloc(sizeof(*root->ops) * children, GFP_KERNEL);
1487 root->val = children;
1488 data.children = children;
1489 return walk_pred_tree(preds, root, fold_pred_cb, &data);
1492 static int fold_pred_tree_cb(enum move_type move, struct filter_pred *pred,
1493 int *err, void *data)
1495 struct filter_pred *preds = data;
1497 if (move != MOVE_DOWN)
1498 return WALK_PRED_DEFAULT;
1499 if (!(pred->index & FILTER_PRED_FOLD))
1500 return WALK_PRED_DEFAULT;
1502 *err = fold_pred(preds, pred);
1504 return WALK_PRED_ABORT;
1506 /* eveyrhing below is folded, continue with parent */
1507 return WALK_PRED_PARENT;
1511 * To optimize the processing of the ops, if we have several "ors" or
1512 * "ands" together, we can put them in an array and process them all
1513 * together speeding up the filter logic.
1515 static int fold_pred_tree(struct event_filter *filter,
1516 struct filter_pred *root)
1518 return walk_pred_tree(filter->preds, root, fold_pred_tree_cb,
1522 static int replace_preds(struct ftrace_event_call *call,
1523 struct event_filter *filter,
1524 struct filter_parse_state *ps,
1525 char *filter_string,
1528 char *operand1 = NULL, *operand2 = NULL;
1529 struct filter_pred *pred;
1530 struct filter_pred *root;
1531 struct postfix_elt *elt;
1532 struct pred_stack stack = { }; /* init to NULL */
1536 n_preds = count_preds(ps);
1537 if (n_preds >= MAX_FILTER_PRED) {
1538 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1542 err = check_preds(ps);
1547 err = __alloc_pred_stack(&stack, n_preds);
1550 err = __alloc_preds(filter, n_preds);
1556 list_for_each_entry(elt, &ps->postfix, list) {
1557 if (elt->op == OP_NONE) {
1559 operand1 = elt->operand;
1561 operand2 = elt->operand;
1563 parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
1570 if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
1571 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1576 pred = create_pred(ps, call, elt->op, operand1, operand2);
1583 err = filter_add_pred(ps, filter, pred, &stack);
1588 operand1 = operand2 = NULL;
1592 /* We should have one item left on the stack */
1593 pred = __pop_pred_stack(&stack);
1596 /* This item is where we start from in matching */
1598 /* Make sure the stack is empty */
1599 pred = __pop_pred_stack(&stack);
1600 if (WARN_ON(pred)) {
1602 filter->root = NULL;
1605 err = check_pred_tree(filter, root);
1609 /* Optimize the tree */
1610 err = fold_pred_tree(filter, root);
1614 /* We don't set root until we know it works */
1616 filter->root = root;
1621 __free_pred_stack(&stack);
1625 struct filter_list {
1626 struct list_head list;
1627 struct event_filter *filter;
1630 static int replace_system_preds(struct event_subsystem *system,
1631 struct filter_parse_state *ps,
1632 char *filter_string)
1634 struct ftrace_event_call *call;
1635 struct filter_list *filter_item;
1636 struct filter_list *tmp;
1637 LIST_HEAD(filter_list);
1641 list_for_each_entry(call, &ftrace_events, list) {
1643 if (strcmp(call->class->system, system->name) != 0)
1647 * Try to see if the filter can be applied
1648 * (filter arg is ignored on dry_run)
1650 err = replace_preds(call, NULL, ps, filter_string, true);
1652 call->flags |= TRACE_EVENT_FL_NO_SET_FILTER;
1654 call->flags &= ~TRACE_EVENT_FL_NO_SET_FILTER;
1657 list_for_each_entry(call, &ftrace_events, list) {
1658 struct event_filter *filter;
1660 if (strcmp(call->class->system, system->name) != 0)
1663 if (call->flags & TRACE_EVENT_FL_NO_SET_FILTER)
1666 filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
1670 list_add_tail(&filter_item->list, &filter_list);
1672 filter_item->filter = __alloc_filter();
1673 if (!filter_item->filter)
1675 filter = filter_item->filter;
1677 /* Can only fail on no memory */
1678 err = replace_filter_string(filter, filter_string);
1682 err = replace_preds(call, filter, ps, filter_string, false);
1684 filter_disable(call);
1685 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1686 append_filter_err(ps, filter);
1688 call->flags |= TRACE_EVENT_FL_FILTERED;
1690 * Regardless of if this returned an error, we still
1691 * replace the filter for the call.
1693 filter = call->filter;
1694 rcu_assign_pointer(call->filter, filter_item->filter);
1695 filter_item->filter = filter;
1704 * The calls can still be using the old filters.
1705 * Do a synchronize_sched() to ensure all calls are
1706 * done with them before we free them.
1708 synchronize_sched();
1709 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1710 __free_filter(filter_item->filter);
1711 list_del(&filter_item->list);
1716 /* No call succeeded */
1717 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1718 list_del(&filter_item->list);
1721 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1724 /* If any call succeeded, we still need to sync */
1726 synchronize_sched();
1727 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1728 __free_filter(filter_item->filter);
1729 list_del(&filter_item->list);
1735 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
1737 struct filter_parse_state *ps;
1738 struct event_filter *filter;
1739 struct event_filter *tmp;
1742 mutex_lock(&event_mutex);
1744 if (!strcmp(strstrip(filter_string), "0")) {
1745 filter_disable(call);
1746 filter = call->filter;
1749 RCU_INIT_POINTER(call->filter, NULL);
1750 /* Make sure the filter is not being used */
1751 synchronize_sched();
1752 __free_filter(filter);
1757 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1761 filter = __alloc_filter();
1767 replace_filter_string(filter, filter_string);
1769 parse_init(ps, filter_ops, filter_string);
1770 err = filter_parse(ps);
1772 append_filter_err(ps, filter);
1776 err = replace_preds(call, filter, ps, filter_string, false);
1778 filter_disable(call);
1779 append_filter_err(ps, filter);
1781 call->flags |= TRACE_EVENT_FL_FILTERED;
1784 * Always swap the call filter with the new filter
1785 * even if there was an error. If there was an error
1786 * in the filter, we disable the filter and show the error
1790 rcu_assign_pointer(call->filter, filter);
1792 /* Make sure the call is done with the filter */
1793 synchronize_sched();
1796 filter_opstack_clear(ps);
1800 mutex_unlock(&event_mutex);
1805 int apply_subsystem_event_filter(struct event_subsystem *system,
1806 char *filter_string)
1808 struct filter_parse_state *ps;
1809 struct event_filter *filter;
1812 mutex_lock(&event_mutex);
1814 /* Make sure the system still has events */
1815 if (!system->nr_events) {
1820 if (!strcmp(strstrip(filter_string), "0")) {
1821 filter_free_subsystem_preds(system);
1822 remove_filter_string(system->filter);
1823 filter = system->filter;
1824 system->filter = NULL;
1825 /* Ensure all filters are no longer used */
1826 synchronize_sched();
1827 filter_free_subsystem_filters(system);
1828 __free_filter(filter);
1833 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1837 filter = __alloc_filter();
1841 replace_filter_string(filter, filter_string);
1843 * No event actually uses the system filter
1844 * we can free it without synchronize_sched().
1846 __free_filter(system->filter);
1847 system->filter = filter;
1849 parse_init(ps, filter_ops, filter_string);
1850 err = filter_parse(ps);
1852 append_filter_err(ps, system->filter);
1856 err = replace_system_preds(system, ps, filter_string);
1858 append_filter_err(ps, system->filter);
1861 filter_opstack_clear(ps);
1865 mutex_unlock(&event_mutex);
1870 #ifdef CONFIG_PERF_EVENTS
1872 void ftrace_profile_free_filter(struct perf_event *event)
1874 struct event_filter *filter = event->filter;
1876 event->filter = NULL;
1877 __free_filter(filter);
1880 int ftrace_profile_set_filter(struct perf_event *event, int event_id,
1884 struct event_filter *filter;
1885 struct filter_parse_state *ps;
1886 struct ftrace_event_call *call;
1888 mutex_lock(&event_mutex);
1890 call = event->tp_event;
1900 filter = __alloc_filter();
1902 err = PTR_ERR(filter);
1907 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1911 parse_init(ps, filter_ops, filter_str);
1912 err = filter_parse(ps);
1916 err = replace_preds(call, filter, ps, filter_str, false);
1918 event->filter = filter;
1921 filter_opstack_clear(ps);
1927 __free_filter(filter);
1930 mutex_unlock(&event_mutex);
1935 #endif /* CONFIG_PERF_EVENTS */
1937 #ifdef CONFIG_FTRACE_STARTUP_TEST
1939 #include <linux/types.h>
1940 #include <linux/tracepoint.h>
1942 #define CREATE_TRACE_POINTS
1943 #include "trace_events_filter_test.h"
1945 static int test_get_filter(char *filter_str, struct ftrace_event_call *call,
1946 struct event_filter **pfilter)
1948 struct event_filter *filter;
1949 struct filter_parse_state *ps;
1952 filter = __alloc_filter();
1956 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1960 parse_init(ps, filter_ops, filter_str);
1961 err = filter_parse(ps);
1965 err = replace_preds(call, filter, ps, filter_str, false);
1970 filter_opstack_clear(ps);
1976 __free_filter(filter);
1982 #define DATA_REC(m, va, vb, vc, vd, ve, vf, vg, vh, nvisit) \
1985 .rec = { .a = va, .b = vb, .c = vc, .d = vd, \
1986 .e = ve, .f = vf, .g = vg, .h = vh }, \
1988 .not_visited = nvisit, \
1993 static struct test_filter_data_t {
1995 struct ftrace_raw_ftrace_test_filter rec;
1998 } test_filter_data[] = {
1999 #define FILTER "a == 1 && b == 1 && c == 1 && d == 1 && " \
2000 "e == 1 && f == 1 && g == 1 && h == 1"
2001 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, ""),
2002 DATA_REC(NO, 0, 1, 1, 1, 1, 1, 1, 1, "bcdefgh"),
2003 DATA_REC(NO, 1, 1, 1, 1, 1, 1, 1, 0, ""),
2005 #define FILTER "a == 1 || b == 1 || c == 1 || d == 1 || " \
2006 "e == 1 || f == 1 || g == 1 || h == 1"
2007 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
2008 DATA_REC(YES, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2009 DATA_REC(YES, 1, 0, 0, 0, 0, 0, 0, 0, "bcdefgh"),
2011 #define FILTER "(a == 1 || b == 1) && (c == 1 || d == 1) && " \
2012 "(e == 1 || f == 1) && (g == 1 || h == 1)"
2013 DATA_REC(NO, 0, 0, 1, 1, 1, 1, 1, 1, "dfh"),
2014 DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2015 DATA_REC(YES, 1, 0, 1, 0, 0, 1, 0, 1, "bd"),
2016 DATA_REC(NO, 1, 0, 1, 0, 0, 1, 0, 0, "bd"),
2018 #define FILTER "(a == 1 && b == 1) || (c == 1 && d == 1) || " \
2019 "(e == 1 && f == 1) || (g == 1 && h == 1)"
2020 DATA_REC(YES, 1, 0, 1, 1, 1, 1, 1, 1, "efgh"),
2021 DATA_REC(YES, 0, 0, 0, 0, 0, 0, 1, 1, ""),
2022 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2024 #define FILTER "(a == 1 && b == 1) && (c == 1 && d == 1) && " \
2025 "(e == 1 && f == 1) || (g == 1 && h == 1)"
2026 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 0, "gh"),
2027 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
2028 DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, ""),
2030 #define FILTER "((a == 1 || b == 1) || (c == 1 || d == 1) || " \
2031 "(e == 1 || f == 1)) && (g == 1 || h == 1)"
2032 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 1, "bcdef"),
2033 DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
2034 DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, "h"),
2036 #define FILTER "((((((((a == 1) && (b == 1)) || (c == 1)) && (d == 1)) || " \
2037 "(e == 1)) && (f == 1)) || (g == 1)) && (h == 1))"
2038 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "ceg"),
2039 DATA_REC(NO, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2040 DATA_REC(NO, 1, 0, 1, 0, 1, 0, 1, 0, ""),
2042 #define FILTER "((((((((a == 1) || (b == 1)) && (c == 1)) || (d == 1)) && " \
2043 "(e == 1)) || (f == 1)) && (g == 1)) || (h == 1))"
2044 DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "bdfh"),
2045 DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
2046 DATA_REC(YES, 1, 0, 1, 0, 1, 0, 1, 0, "bdfh"),
2054 #define DATA_CNT (sizeof(test_filter_data)/sizeof(struct test_filter_data_t))
2056 static int test_pred_visited;
2058 static int test_pred_visited_fn(struct filter_pred *pred, void *event)
2060 struct ftrace_event_field *field = pred->field;
2062 test_pred_visited = 1;
2063 printk(KERN_INFO "\npred visited %s\n", field->name);
2067 static int test_walk_pred_cb(enum move_type move, struct filter_pred *pred,
2068 int *err, void *data)
2070 char *fields = data;
2072 if ((move == MOVE_DOWN) &&
2073 (pred->left == FILTER_PRED_INVALID)) {
2074 struct ftrace_event_field *field = pred->field;
2077 WARN(1, "all leafs should have field defined");
2078 return WALK_PRED_DEFAULT;
2080 if (!strchr(fields, *field->name))
2081 return WALK_PRED_DEFAULT;
2084 pred->fn = test_pred_visited_fn;
2086 return WALK_PRED_DEFAULT;
2089 static __init int ftrace_test_event_filter(void)
2093 printk(KERN_INFO "Testing ftrace filter: ");
2095 for (i = 0; i < DATA_CNT; i++) {
2096 struct event_filter *filter = NULL;
2097 struct test_filter_data_t *d = &test_filter_data[i];
2100 err = test_get_filter(d->filter, &event_ftrace_test_filter,
2104 "Failed to get filter for '%s', err %d\n",
2110 * The preemption disabling is not really needed for self
2111 * tests, but the rcu dereference will complain without it.
2114 if (*d->not_visited)
2115 walk_pred_tree(filter->preds, filter->root,
2119 test_pred_visited = 0;
2120 err = filter_match_preds(filter, &d->rec);
2123 __free_filter(filter);
2125 if (test_pred_visited) {
2127 "Failed, unwanted pred visited for filter %s\n",
2132 if (err != d->match) {
2134 "Failed to match filter '%s', expected %d\n",
2135 d->filter, d->match);
2141 printk(KERN_CONT "OK\n");
2146 late_initcall(ftrace_test_event_filter);
2148 #endif /* CONFIG_FTRACE_STARTUP_TEST */