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];
385 * A series of AND or ORs where found together. Instead of
386 * climbing up and down the tree branches, an array of the
387 * ops were made in order of checks. We can just move across
388 * the array and short circuit if needed.
390 static int process_ops(struct filter_pred *preds,
391 struct filter_pred *op, void *rec)
393 struct filter_pred *pred;
399 * Micro-optimization: We set type to true if op
400 * is an OR and false otherwise (AND). Then we
401 * just need to test if the match is equal to
402 * the type, and if it is, we can short circuit the
403 * rest of the checks:
405 * if ((match && op->op == OP_OR) ||
406 * (!match && op->op == OP_AND))
409 type = op->op == OP_OR;
411 for (i = 0; i < op->val; i++) {
412 pred = &preds[op->ops[i]];
413 match = pred->fn(pred, rec);
420 /* return 1 if event matches, 0 otherwise (discard) */
421 int filter_match_preds(struct event_filter *filter, void *rec)
424 enum move_type move = MOVE_DOWN;
425 struct filter_pred *preds;
426 struct filter_pred *pred;
427 struct filter_pred *root;
431 /* no filter is considered a match */
435 n_preds = filter->n_preds;
441 * n_preds, root and filter->preds are protect with preemption disabled.
443 preds = rcu_dereference_sched(filter->preds);
444 root = rcu_dereference_sched(filter->root);
450 /* match is currently meaningless */
456 /* only AND and OR have children */
457 if (pred->left != FILTER_PRED_INVALID) {
458 /* If ops is set, then it was folded. */
460 /* keep going to down the left side */
461 pred = &preds[pred->left];
464 /* We can treat folded ops as a leaf node */
465 match = process_ops(preds, pred, rec);
467 match = pred->fn(pred, rec);
468 /* If this pred is the only pred */
471 pred = get_pred_parent(pred, preds,
472 pred->parent, &move);
474 case MOVE_UP_FROM_LEFT:
476 * Check for short circuits.
478 * Optimization: !!match == (pred->op == OP_OR)
480 * if ((match && pred->op == OP_OR) ||
481 * (!match && pred->op == OP_AND))
483 if (!!match == (pred->op == OP_OR)) {
486 pred = get_pred_parent(pred, preds,
487 pred->parent, &move);
490 /* now go down the right side of the tree. */
491 pred = &preds[pred->right];
494 case MOVE_UP_FROM_RIGHT:
495 /* We finished this equation. */
498 pred = get_pred_parent(pred, preds,
499 pred->parent, &move);
507 EXPORT_SYMBOL_GPL(filter_match_preds);
509 static void parse_error(struct filter_parse_state *ps, int err, int pos)
512 ps->lasterr_pos = pos;
515 static void remove_filter_string(struct event_filter *filter)
520 kfree(filter->filter_string);
521 filter->filter_string = NULL;
524 static int replace_filter_string(struct event_filter *filter,
527 kfree(filter->filter_string);
528 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
529 if (!filter->filter_string)
535 static int append_filter_string(struct event_filter *filter,
539 char *new_filter_string;
541 BUG_ON(!filter->filter_string);
542 newlen = strlen(filter->filter_string) + strlen(string) + 1;
543 new_filter_string = kmalloc(newlen, GFP_KERNEL);
544 if (!new_filter_string)
547 strcpy(new_filter_string, filter->filter_string);
548 strcat(new_filter_string, string);
549 kfree(filter->filter_string);
550 filter->filter_string = new_filter_string;
555 static void append_filter_err(struct filter_parse_state *ps,
556 struct event_filter *filter)
558 int pos = ps->lasterr_pos;
561 buf = (char *)__get_free_page(GFP_TEMPORARY);
565 append_filter_string(filter, "\n");
566 memset(buf, ' ', PAGE_SIZE);
567 if (pos > PAGE_SIZE - 128)
570 pbuf = &buf[pos] + 1;
572 sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
573 append_filter_string(filter, buf);
574 free_page((unsigned long) buf);
577 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
579 struct event_filter *filter;
581 mutex_lock(&event_mutex);
582 filter = call->filter;
583 if (filter && filter->filter_string)
584 trace_seq_printf(s, "%s\n", filter->filter_string);
586 trace_seq_printf(s, "none\n");
587 mutex_unlock(&event_mutex);
590 void print_subsystem_event_filter(struct event_subsystem *system,
593 struct event_filter *filter;
595 mutex_lock(&event_mutex);
596 filter = system->filter;
597 if (filter && filter->filter_string)
598 trace_seq_printf(s, "%s\n", filter->filter_string);
600 trace_seq_printf(s, "none\n");
601 mutex_unlock(&event_mutex);
604 static struct ftrace_event_field *
605 __find_event_field(struct list_head *head, char *name)
607 struct ftrace_event_field *field;
609 list_for_each_entry(field, head, link) {
610 if (!strcmp(field->name, name))
617 static struct ftrace_event_field *
618 find_event_field(struct ftrace_event_call *call, char *name)
620 struct ftrace_event_field *field;
621 struct list_head *head;
623 field = __find_event_field(&ftrace_common_fields, name);
627 head = trace_get_fields(call);
628 return __find_event_field(head, name);
631 static void filter_free_pred(struct filter_pred *pred)
636 kfree(pred->field_name);
640 static void filter_clear_pred(struct filter_pred *pred)
642 kfree(pred->field_name);
643 pred->field_name = NULL;
647 static int __alloc_pred_stack(struct pred_stack *stack, int n_preds)
649 stack->preds = kzalloc(sizeof(*stack->preds)*(n_preds + 1), GFP_KERNEL);
652 stack->index = n_preds;
656 static void __free_pred_stack(struct pred_stack *stack)
662 static int __push_pred_stack(struct pred_stack *stack,
663 struct filter_pred *pred)
665 int index = stack->index;
667 if (WARN_ON(index == 0))
670 stack->preds[--index] = pred;
671 stack->index = index;
675 static struct filter_pred *
676 __pop_pred_stack(struct pred_stack *stack)
678 struct filter_pred *pred;
679 int index = stack->index;
681 pred = stack->preds[index++];
685 stack->index = index;
689 static int filter_set_pred(struct event_filter *filter,
691 struct pred_stack *stack,
692 struct filter_pred *src,
695 struct filter_pred *dest = &filter->preds[idx];
696 struct filter_pred *left;
697 struct filter_pred *right;
700 if (src->field_name) {
701 dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
702 if (!dest->field_name)
708 if (dest->op == OP_OR || dest->op == OP_AND) {
709 right = __pop_pred_stack(stack);
710 left = __pop_pred_stack(stack);
714 * If both children can be folded
715 * and they are the same op as this op or a leaf,
716 * then this op can be folded.
718 if (left->index & FILTER_PRED_FOLD &&
719 (left->op == dest->op ||
720 left->left == FILTER_PRED_INVALID) &&
721 right->index & FILTER_PRED_FOLD &&
722 (right->op == dest->op ||
723 right->left == FILTER_PRED_INVALID))
724 dest->index |= FILTER_PRED_FOLD;
726 dest->left = left->index & ~FILTER_PRED_FOLD;
727 dest->right = right->index & ~FILTER_PRED_FOLD;
728 left->parent = dest->index & ~FILTER_PRED_FOLD;
729 right->parent = dest->index | FILTER_PRED_IS_RIGHT;
732 * Make dest->left invalid to be used as a quick
733 * way to know this is a leaf node.
735 dest->left = FILTER_PRED_INVALID;
737 /* All leafs allow folding the parent ops. */
738 dest->index |= FILTER_PRED_FOLD;
741 return __push_pred_stack(stack, dest);
744 static void __free_preds(struct event_filter *filter)
749 for (i = 0; i < filter->a_preds; i++)
750 kfree(filter->preds[i].field_name);
751 kfree(filter->preds);
752 filter->preds = NULL;
758 static void filter_disable(struct ftrace_event_call *call)
760 call->flags &= ~TRACE_EVENT_FL_FILTERED;
763 static void __free_filter(struct event_filter *filter)
768 __free_preds(filter);
769 kfree(filter->filter_string);
774 * Called when destroying the ftrace_event_call.
775 * The call is being freed, so we do not need to worry about
776 * the call being currently used. This is for module code removing
777 * the tracepoints from within it.
779 void destroy_preds(struct ftrace_event_call *call)
781 __free_filter(call->filter);
785 static struct event_filter *__alloc_filter(void)
787 struct event_filter *filter;
789 filter = kzalloc(sizeof(*filter), GFP_KERNEL);
793 static int __alloc_preds(struct event_filter *filter, int n_preds)
795 struct filter_pred *pred;
799 __free_preds(filter);
802 kzalloc(sizeof(*filter->preds) * n_preds, GFP_KERNEL);
807 filter->a_preds = n_preds;
810 for (i = 0; i < n_preds; i++) {
811 pred = &filter->preds[i];
812 pred->fn = filter_pred_none;
818 static void filter_free_subsystem_preds(struct event_subsystem *system)
820 struct ftrace_event_call *call;
822 list_for_each_entry(call, &ftrace_events, list) {
823 if (strcmp(call->class->system, system->name) != 0)
826 filter_disable(call);
827 remove_filter_string(call->filter);
831 static void filter_free_subsystem_filters(struct event_subsystem *system)
833 struct ftrace_event_call *call;
835 list_for_each_entry(call, &ftrace_events, list) {
836 if (strcmp(call->class->system, system->name) != 0)
838 __free_filter(call->filter);
843 static int filter_add_pred_fn(struct filter_parse_state *ps,
844 struct ftrace_event_call *call,
845 struct event_filter *filter,
846 struct filter_pred *pred,
847 struct pred_stack *stack,
852 if (WARN_ON(filter->n_preds == filter->a_preds)) {
853 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
857 idx = filter->n_preds;
858 filter_clear_pred(&filter->preds[idx]);
859 err = filter_set_pred(filter, idx, stack, pred, fn);
868 int filter_assign_type(const char *type)
870 if (strstr(type, "__data_loc") && strstr(type, "char"))
871 return FILTER_DYN_STRING;
873 if (strchr(type, '[') && strstr(type, "char"))
874 return FILTER_STATIC_STRING;
879 static bool is_string_field(struct ftrace_event_field *field)
881 return field->filter_type == FILTER_DYN_STRING ||
882 field->filter_type == FILTER_STATIC_STRING ||
883 field->filter_type == FILTER_PTR_STRING;
886 static int is_legal_op(struct ftrace_event_field *field, int op)
888 if (is_string_field(field) &&
889 (op != OP_EQ && op != OP_NE && op != OP_GLOB))
891 if (!is_string_field(field) && op == OP_GLOB)
897 static filter_pred_fn_t select_comparison_fn(int op, int field_size,
900 filter_pred_fn_t fn = NULL;
902 switch (field_size) {
904 if (op == OP_EQ || op == OP_NE)
906 else if (field_is_signed)
907 fn = filter_pred_s64;
909 fn = filter_pred_u64;
912 if (op == OP_EQ || op == OP_NE)
914 else if (field_is_signed)
915 fn = filter_pred_s32;
917 fn = filter_pred_u32;
920 if (op == OP_EQ || op == OP_NE)
922 else if (field_is_signed)
923 fn = filter_pred_s16;
925 fn = filter_pred_u16;
928 if (op == OP_EQ || op == OP_NE)
930 else if (field_is_signed)
940 static int filter_add_pred(struct filter_parse_state *ps,
941 struct ftrace_event_call *call,
942 struct event_filter *filter,
943 struct filter_pred *pred,
944 struct pred_stack *stack,
947 struct ftrace_event_field *field;
949 unsigned long long val;
952 fn = pred->fn = filter_pred_none;
954 if (pred->op == OP_AND)
956 else if (pred->op == OP_OR)
959 field = find_event_field(call, pred->field_name);
961 parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
965 pred->offset = field->offset;
967 if (!is_legal_op(field, pred->op)) {
968 parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
972 if (is_string_field(field)) {
973 filter_build_regex(pred);
975 if (field->filter_type == FILTER_STATIC_STRING) {
976 fn = filter_pred_string;
977 pred->regex.field_len = field->size;
978 } else if (field->filter_type == FILTER_DYN_STRING)
979 fn = filter_pred_strloc;
981 fn = filter_pred_pchar;
983 if (field->is_signed)
984 ret = strict_strtoll(pred->regex.pattern, 0, &val);
986 ret = strict_strtoull(pred->regex.pattern, 0, &val);
988 parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
993 fn = select_comparison_fn(pred->op, field->size,
996 parse_error(ps, FILT_ERR_INVALID_OP, 0);
1001 if (pred->op == OP_NE)
1006 return filter_add_pred_fn(ps, call, filter, pred, stack, fn);
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(int op, char *operand1, char *operand2)
1307 struct filter_pred *pred;
1309 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
1313 pred->field_name = kstrdup(operand1, GFP_KERNEL);
1314 if (!pred->field_name) {
1319 strcpy(pred->regex.pattern, operand2);
1320 pred->regex.len = strlen(pred->regex.pattern);
1327 static struct filter_pred *create_logical_pred(int op)
1329 struct filter_pred *pred;
1331 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
1340 static int check_preds(struct filter_parse_state *ps)
1342 int n_normal_preds = 0, n_logical_preds = 0;
1343 struct postfix_elt *elt;
1345 list_for_each_entry(elt, &ps->postfix, list) {
1346 if (elt->op == OP_NONE)
1349 if (elt->op == OP_AND || elt->op == OP_OR) {
1356 if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
1357 parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
1364 static int count_preds(struct filter_parse_state *ps)
1366 struct postfix_elt *elt;
1369 list_for_each_entry(elt, &ps->postfix, list) {
1370 if (elt->op == OP_NONE)
1379 * The tree is walked at filtering of an event. If the tree is not correctly
1380 * built, it may cause an infinite loop. Check here that the tree does
1383 static int check_pred_tree(struct event_filter *filter,
1384 struct filter_pred *root)
1386 struct filter_pred *preds;
1387 struct filter_pred *pred;
1388 enum move_type move = MOVE_DOWN;
1394 * The max that we can hit a node is three times.
1395 * Once going down, once coming up from left, and
1396 * once coming up from right. This is more than enough
1397 * since leafs are only hit a single time.
1399 max = 3 * filter->n_preds;
1401 preds = filter->preds;
1407 if (WARN_ON(count++ > max))
1412 if (pred->left != FILTER_PRED_INVALID) {
1413 pred = &preds[pred->left];
1416 /* A leaf at the root is just a leaf in the tree */
1419 pred = get_pred_parent(pred, preds,
1420 pred->parent, &move);
1422 case MOVE_UP_FROM_LEFT:
1423 pred = &preds[pred->right];
1426 case MOVE_UP_FROM_RIGHT:
1429 pred = get_pred_parent(pred, preds,
1430 pred->parent, &move);
1440 static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
1442 struct filter_pred *pred;
1443 enum move_type move = MOVE_DOWN;
1452 if (pred->left != FILTER_PRED_INVALID) {
1453 pred = &preds[pred->left];
1456 /* A leaf at the root is just a leaf in the tree */
1460 pred = get_pred_parent(pred, preds,
1461 pred->parent, &move);
1463 case MOVE_UP_FROM_LEFT:
1464 pred = &preds[pred->right];
1467 case MOVE_UP_FROM_RIGHT:
1470 pred = get_pred_parent(pred, preds,
1471 pred->parent, &move);
1480 static int fold_pred(struct filter_pred *preds, struct filter_pred *root)
1482 struct filter_pred *pred;
1483 enum move_type move = MOVE_DOWN;
1488 /* No need to keep the fold flag */
1489 root->index &= ~FILTER_PRED_FOLD;
1491 /* If the root is a leaf then do nothing */
1492 if (root->left == FILTER_PRED_INVALID)
1495 /* count the children */
1496 children = count_leafs(preds, &preds[root->left]);
1497 children += count_leafs(preds, &preds[root->right]);
1499 root->ops = kzalloc(sizeof(*root->ops) * children, GFP_KERNEL);
1503 root->val = children;
1509 if (pred->left != FILTER_PRED_INVALID) {
1510 pred = &preds[pred->left];
1513 if (WARN_ON(count == children))
1515 pred->index &= ~FILTER_PRED_FOLD;
1516 root->ops[count++] = pred->index;
1517 pred = get_pred_parent(pred, preds,
1518 pred->parent, &move);
1520 case MOVE_UP_FROM_LEFT:
1521 pred = &preds[pred->right];
1524 case MOVE_UP_FROM_RIGHT:
1527 pred = get_pred_parent(pred, preds,
1528 pred->parent, &move);
1538 * To optimize the processing of the ops, if we have several "ors" or
1539 * "ands" together, we can put them in an array and process them all
1540 * together speeding up the filter logic.
1542 static int fold_pred_tree(struct event_filter *filter,
1543 struct filter_pred *root)
1545 struct filter_pred *preds;
1546 struct filter_pred *pred;
1547 enum move_type move = MOVE_DOWN;
1551 preds = filter->preds;
1559 if (pred->index & FILTER_PRED_FOLD) {
1560 err = fold_pred(preds, pred);
1563 /* Folded nodes are like leafs */
1564 } else if (pred->left != FILTER_PRED_INVALID) {
1565 pred = &preds[pred->left];
1569 /* A leaf at the root is just a leaf in the tree */
1572 pred = get_pred_parent(pred, preds,
1573 pred->parent, &move);
1575 case MOVE_UP_FROM_LEFT:
1576 pred = &preds[pred->right];
1579 case MOVE_UP_FROM_RIGHT:
1582 pred = get_pred_parent(pred, preds,
1583 pred->parent, &move);
1592 static int replace_preds(struct ftrace_event_call *call,
1593 struct event_filter *filter,
1594 struct filter_parse_state *ps,
1595 char *filter_string,
1598 char *operand1 = NULL, *operand2 = NULL;
1599 struct filter_pred *pred;
1600 struct filter_pred *root;
1601 struct postfix_elt *elt;
1602 struct pred_stack stack = { }; /* init to NULL */
1606 n_preds = count_preds(ps);
1607 if (n_preds >= MAX_FILTER_PRED) {
1608 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1612 err = check_preds(ps);
1617 err = __alloc_pred_stack(&stack, n_preds);
1620 err = __alloc_preds(filter, n_preds);
1626 list_for_each_entry(elt, &ps->postfix, list) {
1627 if (elt->op == OP_NONE) {
1629 operand1 = elt->operand;
1631 operand2 = elt->operand;
1633 parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
1640 if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
1641 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
1646 if (elt->op == OP_AND || elt->op == OP_OR) {
1647 pred = create_logical_pred(elt->op);
1651 if (!operand1 || !operand2) {
1652 parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
1657 pred = create_pred(elt->op, operand1, operand2);
1663 err = filter_add_pred(ps, call, filter, pred, &stack, dry_run);
1664 filter_free_pred(pred);
1668 operand1 = operand2 = NULL;
1672 /* We should have one item left on the stack */
1673 pred = __pop_pred_stack(&stack);
1676 /* This item is where we start from in matching */
1678 /* Make sure the stack is empty */
1679 pred = __pop_pred_stack(&stack);
1680 if (WARN_ON(pred)) {
1682 filter->root = NULL;
1685 err = check_pred_tree(filter, root);
1689 /* Optimize the tree */
1690 err = fold_pred_tree(filter, root);
1694 /* We don't set root until we know it works */
1696 filter->root = root;
1701 __free_pred_stack(&stack);
1705 struct filter_list {
1706 struct list_head list;
1707 struct event_filter *filter;
1710 static int replace_system_preds(struct event_subsystem *system,
1711 struct filter_parse_state *ps,
1712 char *filter_string)
1714 struct ftrace_event_call *call;
1715 struct filter_list *filter_item;
1716 struct filter_list *tmp;
1717 LIST_HEAD(filter_list);
1721 list_for_each_entry(call, &ftrace_events, list) {
1723 if (strcmp(call->class->system, system->name) != 0)
1727 * Try to see if the filter can be applied
1728 * (filter arg is ignored on dry_run)
1730 err = replace_preds(call, NULL, ps, filter_string, true);
1735 list_for_each_entry(call, &ftrace_events, list) {
1736 struct event_filter *filter;
1738 if (strcmp(call->class->system, system->name) != 0)
1741 filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
1745 list_add_tail(&filter_item->list, &filter_list);
1747 filter_item->filter = __alloc_filter();
1748 if (!filter_item->filter)
1750 filter = filter_item->filter;
1752 /* Can only fail on no memory */
1753 err = replace_filter_string(filter, filter_string);
1757 err = replace_preds(call, filter, ps, filter_string, false);
1759 filter_disable(call);
1760 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1761 append_filter_err(ps, filter);
1763 call->flags |= TRACE_EVENT_FL_FILTERED;
1765 * Regardless of if this returned an error, we still
1766 * replace the filter for the call.
1768 filter = call->filter;
1769 call->filter = filter_item->filter;
1770 filter_item->filter = filter;
1779 * The calls can still be using the old filters.
1780 * Do a synchronize_sched() to ensure all calls are
1781 * done with them before we free them.
1783 synchronize_sched();
1784 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1785 __free_filter(filter_item->filter);
1786 list_del(&filter_item->list);
1791 /* No call succeeded */
1792 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1793 list_del(&filter_item->list);
1796 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
1799 /* If any call succeeded, we still need to sync */
1801 synchronize_sched();
1802 list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
1803 __free_filter(filter_item->filter);
1804 list_del(&filter_item->list);
1810 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
1812 struct filter_parse_state *ps;
1813 struct event_filter *filter;
1814 struct event_filter *tmp;
1817 mutex_lock(&event_mutex);
1819 if (!strcmp(strstrip(filter_string), "0")) {
1820 filter_disable(call);
1821 filter = call->filter;
1824 call->filter = NULL;
1825 /* Make sure the filter is not being used */
1826 synchronize_sched();
1827 __free_filter(filter);
1832 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1836 filter = __alloc_filter();
1842 replace_filter_string(filter, filter_string);
1844 parse_init(ps, filter_ops, filter_string);
1845 err = filter_parse(ps);
1847 append_filter_err(ps, filter);
1851 err = replace_preds(call, filter, ps, filter_string, false);
1853 filter_disable(call);
1854 append_filter_err(ps, filter);
1856 call->flags |= TRACE_EVENT_FL_FILTERED;
1859 * Always swap the call filter with the new filter
1860 * even if there was an error. If there was an error
1861 * in the filter, we disable the filter and show the error
1865 call->filter = filter;
1867 /* Make sure the call is done with the filter */
1868 synchronize_sched();
1871 filter_opstack_clear(ps);
1875 mutex_unlock(&event_mutex);
1880 int apply_subsystem_event_filter(struct event_subsystem *system,
1881 char *filter_string)
1883 struct filter_parse_state *ps;
1884 struct event_filter *filter;
1887 mutex_lock(&event_mutex);
1889 /* Make sure the system still has events */
1890 if (!system->nr_events) {
1895 if (!strcmp(strstrip(filter_string), "0")) {
1896 filter_free_subsystem_preds(system);
1897 remove_filter_string(system->filter);
1898 filter = system->filter;
1899 system->filter = NULL;
1900 /* Ensure all filters are no longer used */
1901 synchronize_sched();
1902 filter_free_subsystem_filters(system);
1903 __free_filter(filter);
1908 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1912 filter = __alloc_filter();
1916 replace_filter_string(filter, filter_string);
1918 * No event actually uses the system filter
1919 * we can free it without synchronize_sched().
1921 __free_filter(system->filter);
1922 system->filter = filter;
1924 parse_init(ps, filter_ops, filter_string);
1925 err = filter_parse(ps);
1927 append_filter_err(ps, system->filter);
1931 err = replace_system_preds(system, ps, filter_string);
1933 append_filter_err(ps, system->filter);
1936 filter_opstack_clear(ps);
1940 mutex_unlock(&event_mutex);
1945 #ifdef CONFIG_PERF_EVENTS
1947 void ftrace_profile_free_filter(struct perf_event *event)
1949 struct event_filter *filter = event->filter;
1951 event->filter = NULL;
1952 __free_filter(filter);
1955 int ftrace_profile_set_filter(struct perf_event *event, int event_id,
1959 struct event_filter *filter;
1960 struct filter_parse_state *ps;
1961 struct ftrace_event_call *call = NULL;
1963 mutex_lock(&event_mutex);
1965 list_for_each_entry(call, &ftrace_events, list) {
1966 if (call->event.type == event_id)
1971 if (&call->list == &ftrace_events)
1978 filter = __alloc_filter();
1980 err = PTR_ERR(filter);
1985 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1989 parse_init(ps, filter_ops, filter_str);
1990 err = filter_parse(ps);
1994 err = replace_preds(call, filter, ps, filter_str, false);
1996 event->filter = filter;
1999 filter_opstack_clear(ps);
2005 __free_filter(filter);
2008 mutex_unlock(&event_mutex);
2013 #endif /* CONFIG_PERF_EVENTS */