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/debugfs.h>
22 #include <linux/uaccess.h>
23 #include <linux/module.h>
24 #include <linux/ctype.h>
25 #include <linux/mutex.h>
28 #include "trace_output.h"
50 static struct filter_op filter_ops[] = {
59 { OP_NONE, "OP_NONE", 0 },
60 { OP_OPEN_PAREN, "(", 0 },
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,
78 static char *err_text[] = {
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",
95 struct list_head list;
101 struct list_head list;
104 struct filter_parse_state {
105 struct filter_op *ops;
106 struct list_head opstack;
107 struct list_head postfix;
118 char string[MAX_FILTER_STR_VAL];
124 DEFINE_COMPARISON_PRED(s64);
125 DEFINE_COMPARISON_PRED(u64);
126 DEFINE_COMPARISON_PRED(s32);
127 DEFINE_COMPARISON_PRED(u32);
128 DEFINE_COMPARISON_PRED(s16);
129 DEFINE_COMPARISON_PRED(u16);
130 DEFINE_COMPARISON_PRED(s8);
131 DEFINE_COMPARISON_PRED(u8);
133 DEFINE_EQUALITY_PRED(64);
134 DEFINE_EQUALITY_PRED(32);
135 DEFINE_EQUALITY_PRED(16);
136 DEFINE_EQUALITY_PRED(8);
138 static int filter_pred_and(struct filter_pred *pred __attribute((unused)),
139 void *event __attribute((unused)),
145 static int filter_pred_or(struct filter_pred *pred __attribute((unused)),
146 void *event __attribute((unused)),
152 /* Filter predicate for fixed sized arrays of characters */
153 static int filter_pred_string(struct filter_pred *pred, void *event,
156 char *addr = (char *)(event + pred->offset);
159 cmp = strncmp(addr, pred->str_val, pred->str_len);
161 match = (!cmp) ^ pred->not;
167 * Filter predicate for dynamic sized arrays of characters.
168 * These are implemented through a list of strings at the end
170 * Also each of these strings have a field in the entry which
171 * contains its offset from the beginning of the entry.
172 * We have then first to get this field, dereference it
173 * and add it to the address of the entry, and at last we have
174 * the address of the string.
176 static int filter_pred_strloc(struct filter_pred *pred, void *event,
179 unsigned short str_loc = *(unsigned short *)(event + pred->offset);
180 char *addr = (char *)(event + str_loc);
183 cmp = strncmp(addr, pred->str_val, pred->str_len);
185 match = (!cmp) ^ pred->not;
190 static int filter_pred_none(struct filter_pred *pred, void *event,
196 /* return 1 if event matches, 0 otherwise (discard) */
197 int filter_match_preds(struct ftrace_event_call *call, void *rec)
199 struct event_filter *filter = call->filter;
200 int match, top = 0, val1 = 0, val2 = 0;
201 int stack[MAX_FILTER_PRED];
202 struct filter_pred *pred;
205 for (i = 0; i < filter->n_preds; i++) {
206 pred = filter->preds[i];
208 match = pred->fn(pred, rec, val1, val2);
209 stack[top++] = match;
212 if (pred->pop_n > top) {
218 match = pred->fn(pred, rec, val1, val2);
219 stack[top++] = match;
224 EXPORT_SYMBOL_GPL(filter_match_preds);
226 static void parse_error(struct filter_parse_state *ps, int err, int pos)
229 ps->lasterr_pos = pos;
232 static void remove_filter_string(struct event_filter *filter)
234 kfree(filter->filter_string);
235 filter->filter_string = NULL;
238 static int replace_filter_string(struct event_filter *filter,
241 kfree(filter->filter_string);
242 filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
243 if (!filter->filter_string)
249 static int append_filter_string(struct event_filter *filter,
253 char *new_filter_string;
255 BUG_ON(!filter->filter_string);
256 newlen = strlen(filter->filter_string) + strlen(string) + 1;
257 new_filter_string = kmalloc(newlen, GFP_KERNEL);
258 if (!new_filter_string)
261 strcpy(new_filter_string, filter->filter_string);
262 strcat(new_filter_string, string);
263 kfree(filter->filter_string);
264 filter->filter_string = new_filter_string;
269 static void append_filter_err(struct filter_parse_state *ps,
270 struct event_filter *filter)
272 int pos = ps->lasterr_pos;
275 buf = (char *)__get_free_page(GFP_TEMPORARY);
279 append_filter_string(filter, "\n");
280 memset(buf, ' ', PAGE_SIZE);
281 if (pos > PAGE_SIZE - 128)
284 pbuf = &buf[pos] + 1;
286 sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
287 append_filter_string(filter, buf);
288 free_page((unsigned long) buf);
291 void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
293 struct event_filter *filter = call->filter;
295 mutex_lock(&event_mutex);
296 if (filter->filter_string)
297 trace_seq_printf(s, "%s\n", filter->filter_string);
299 trace_seq_printf(s, "none\n");
300 mutex_unlock(&event_mutex);
303 void print_subsystem_event_filter(struct event_subsystem *system,
306 struct event_filter *filter = system->filter;
308 mutex_lock(&event_mutex);
309 if (filter->filter_string)
310 trace_seq_printf(s, "%s\n", filter->filter_string);
312 trace_seq_printf(s, "none\n");
313 mutex_unlock(&event_mutex);
316 static struct ftrace_event_field *
317 find_event_field(struct ftrace_event_call *call, char *name)
319 struct ftrace_event_field *field;
321 list_for_each_entry(field, &call->fields, link) {
322 if (!strcmp(field->name, name))
329 static void filter_free_pred(struct filter_pred *pred)
334 kfree(pred->field_name);
338 static void filter_clear_pred(struct filter_pred *pred)
340 kfree(pred->field_name);
341 pred->field_name = NULL;
345 static int filter_set_pred(struct filter_pred *dest,
346 struct filter_pred *src,
350 if (src->field_name) {
351 dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
352 if (!dest->field_name)
360 static void filter_disable_preds(struct ftrace_event_call *call)
362 struct event_filter *filter = call->filter;
365 call->filter_active = 0;
368 for (i = 0; i < MAX_FILTER_PRED; i++)
369 filter->preds[i]->fn = filter_pred_none;
372 void destroy_preds(struct ftrace_event_call *call)
374 struct event_filter *filter = call->filter;
377 for (i = 0; i < MAX_FILTER_PRED; i++) {
378 if (filter->preds[i])
379 filter_free_pred(filter->preds[i]);
381 kfree(filter->preds);
382 kfree(filter->filter_string);
387 int init_preds(struct ftrace_event_call *call)
389 struct event_filter *filter;
390 struct filter_pred *pred;
393 filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
397 call->filter_active = 0;
400 filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
404 for (i = 0; i < MAX_FILTER_PRED; i++) {
405 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
408 pred->fn = filter_pred_none;
409 filter->preds[i] = pred;
419 EXPORT_SYMBOL_GPL(init_preds);
421 static void filter_free_subsystem_preds(struct event_subsystem *system)
423 struct event_filter *filter = system->filter;
424 struct ftrace_event_call *call;
427 if (filter->n_preds) {
428 for (i = 0; i < filter->n_preds; i++)
429 filter_free_pred(filter->preds[i]);
430 kfree(filter->preds);
431 filter->preds = NULL;
435 list_for_each_entry(call, &ftrace_events, list) {
436 if (!call->define_fields)
439 if (!strcmp(call->system, system->name)) {
440 filter_disable_preds(call);
441 remove_filter_string(call->filter);
446 static int filter_add_pred_fn(struct filter_parse_state *ps,
447 struct ftrace_event_call *call,
448 struct filter_pred *pred,
451 struct event_filter *filter = call->filter;
454 if (filter->n_preds == MAX_FILTER_PRED) {
455 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
459 idx = filter->n_preds;
460 filter_clear_pred(filter->preds[idx]);
461 err = filter_set_pred(filter->preds[idx], pred, fn);
466 call->filter_active = 1;
472 FILTER_STATIC_STRING = 1,
476 static int is_string_field(const char *type)
478 if (strstr(type, "__data_loc") && strstr(type, "char"))
479 return FILTER_DYN_STRING;
481 if (strchr(type, '[') && strstr(type, "char"))
482 return FILTER_STATIC_STRING;
487 static int is_legal_op(struct ftrace_event_field *field, int op)
489 if (is_string_field(field->type) && (op != OP_EQ && op != OP_NE))
495 static filter_pred_fn_t select_comparison_fn(int op, int field_size,
498 filter_pred_fn_t fn = NULL;
500 switch (field_size) {
502 if (op == OP_EQ || op == OP_NE)
504 else if (field_is_signed)
505 fn = filter_pred_s64;
507 fn = filter_pred_u64;
510 if (op == OP_EQ || op == OP_NE)
512 else if (field_is_signed)
513 fn = filter_pred_s32;
515 fn = filter_pred_u32;
518 if (op == OP_EQ || op == OP_NE)
520 else if (field_is_signed)
521 fn = filter_pred_s16;
523 fn = filter_pred_u16;
526 if (op == OP_EQ || op == OP_NE)
528 else if (field_is_signed)
538 static int filter_add_pred(struct filter_parse_state *ps,
539 struct ftrace_event_call *call,
540 struct filter_pred *pred)
542 struct ftrace_event_field *field;
544 unsigned long long val;
548 pred->fn = filter_pred_none;
550 if (pred->op == OP_AND) {
552 return filter_add_pred_fn(ps, call, pred, filter_pred_and);
553 } else if (pred->op == OP_OR) {
555 return filter_add_pred_fn(ps, call, pred, filter_pred_or);
558 field = find_event_field(call, pred->field_name);
560 parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
564 pred->offset = field->offset;
566 if (!is_legal_op(field, pred->op)) {
567 parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
571 string_type = is_string_field(field->type);
573 if (string_type == FILTER_STATIC_STRING)
574 fn = filter_pred_string;
576 fn = filter_pred_strloc;
577 pred->str_len = field->size;
578 if (pred->op == OP_NE)
580 return filter_add_pred_fn(ps, call, pred, fn);
582 if (field->is_signed)
583 ret = strict_strtoll(pred->str_val, 0, &val);
585 ret = strict_strtoull(pred->str_val, 0, &val);
587 parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
593 fn = select_comparison_fn(pred->op, field->size, field->is_signed);
595 parse_error(ps, FILT_ERR_INVALID_OP, 0);
599 if (pred->op == OP_NE)
602 return filter_add_pred_fn(ps, call, pred, fn);
605 static int filter_add_subsystem_pred(struct filter_parse_state *ps,
606 struct event_subsystem *system,
607 struct filter_pred *pred,
610 struct event_filter *filter = system->filter;
611 struct ftrace_event_call *call;
614 if (!filter->preds) {
615 filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
622 if (filter->n_preds == MAX_FILTER_PRED) {
623 parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
627 filter->preds[filter->n_preds] = pred;
630 list_for_each_entry(call, &ftrace_events, list) {
632 if (!call->define_fields)
635 if (strcmp(call->system, system->name))
638 err = filter_add_pred(ps, call, pred);
640 filter_free_subsystem_preds(system);
641 parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
644 replace_filter_string(call->filter, filter_string);
650 static void parse_init(struct filter_parse_state *ps,
651 struct filter_op *ops,
654 memset(ps, '\0', sizeof(*ps));
656 ps->infix.string = infix_string;
657 ps->infix.cnt = strlen(infix_string);
660 INIT_LIST_HEAD(&ps->opstack);
661 INIT_LIST_HEAD(&ps->postfix);
664 static char infix_next(struct filter_parse_state *ps)
668 return ps->infix.string[ps->infix.tail++];
671 static char infix_peek(struct filter_parse_state *ps)
673 if (ps->infix.tail == strlen(ps->infix.string))
676 return ps->infix.string[ps->infix.tail];
679 static void infix_advance(struct filter_parse_state *ps)
685 static inline int is_precedence_lower(struct filter_parse_state *ps,
688 return ps->ops[a].precedence < ps->ops[b].precedence;
691 static inline int is_op_char(struct filter_parse_state *ps, char c)
695 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
696 if (ps->ops[i].string[0] == c)
703 static int infix_get_op(struct filter_parse_state *ps, char firstc)
705 char nextc = infix_peek(ps);
713 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
714 if (!strcmp(opstr, ps->ops[i].string)) {
716 return ps->ops[i].id;
722 for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
723 if (!strcmp(opstr, ps->ops[i].string))
724 return ps->ops[i].id;
730 static inline void clear_operand_string(struct filter_parse_state *ps)
732 memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
733 ps->operand.tail = 0;
736 static inline int append_operand_char(struct filter_parse_state *ps, char c)
738 if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
741 ps->operand.string[ps->operand.tail++] = c;
746 static int filter_opstack_push(struct filter_parse_state *ps, int op)
748 struct opstack_op *opstack_op;
750 opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
755 list_add(&opstack_op->list, &ps->opstack);
760 static int filter_opstack_empty(struct filter_parse_state *ps)
762 return list_empty(&ps->opstack);
765 static int filter_opstack_top(struct filter_parse_state *ps)
767 struct opstack_op *opstack_op;
769 if (filter_opstack_empty(ps))
772 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
774 return opstack_op->op;
777 static int filter_opstack_pop(struct filter_parse_state *ps)
779 struct opstack_op *opstack_op;
782 if (filter_opstack_empty(ps))
785 opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
787 list_del(&opstack_op->list);
794 static void filter_opstack_clear(struct filter_parse_state *ps)
796 while (!filter_opstack_empty(ps))
797 filter_opstack_pop(ps);
800 static char *curr_operand(struct filter_parse_state *ps)
802 return ps->operand.string;
805 static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
807 struct postfix_elt *elt;
809 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
814 elt->operand = kstrdup(operand, GFP_KERNEL);
820 list_add_tail(&elt->list, &ps->postfix);
825 static int postfix_append_op(struct filter_parse_state *ps, int op)
827 struct postfix_elt *elt;
829 elt = kmalloc(sizeof(*elt), GFP_KERNEL);
836 list_add_tail(&elt->list, &ps->postfix);
841 static void postfix_clear(struct filter_parse_state *ps)
843 struct postfix_elt *elt;
845 while (!list_empty(&ps->postfix)) {
846 elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
848 list_del(&elt->list);
852 static int filter_parse(struct filter_parse_state *ps)
858 while ((ch = infix_next(ps))) {
870 if (is_op_char(ps, ch)) {
871 op = infix_get_op(ps, ch);
873 parse_error(ps, FILT_ERR_INVALID_OP, 0);
877 if (strlen(curr_operand(ps))) {
878 postfix_append_operand(ps, curr_operand(ps));
879 clear_operand_string(ps);
882 while (!filter_opstack_empty(ps)) {
883 top_op = filter_opstack_top(ps);
884 if (!is_precedence_lower(ps, top_op, op)) {
885 top_op = filter_opstack_pop(ps);
886 postfix_append_op(ps, top_op);
892 filter_opstack_push(ps, op);
897 filter_opstack_push(ps, OP_OPEN_PAREN);
902 if (strlen(curr_operand(ps))) {
903 postfix_append_operand(ps, curr_operand(ps));
904 clear_operand_string(ps);
907 top_op = filter_opstack_pop(ps);
908 while (top_op != OP_NONE) {
909 if (top_op == OP_OPEN_PAREN)
911 postfix_append_op(ps, top_op);
912 top_op = filter_opstack_pop(ps);
914 if (top_op == OP_NONE) {
915 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
921 if (append_operand_char(ps, ch)) {
922 parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
927 if (strlen(curr_operand(ps)))
928 postfix_append_operand(ps, curr_operand(ps));
930 while (!filter_opstack_empty(ps)) {
931 top_op = filter_opstack_pop(ps);
932 if (top_op == OP_NONE)
934 if (top_op == OP_OPEN_PAREN) {
935 parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
938 postfix_append_op(ps, top_op);
944 static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
946 struct filter_pred *pred;
948 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
952 pred->field_name = kstrdup(operand1, GFP_KERNEL);
953 if (!pred->field_name) {
958 strcpy(pred->str_val, operand2);
959 pred->str_len = strlen(operand2);
966 static struct filter_pred *create_logical_pred(int op)
968 struct filter_pred *pred;
970 pred = kzalloc(sizeof(*pred), GFP_KERNEL);
979 static int check_preds(struct filter_parse_state *ps)
981 int n_normal_preds = 0, n_logical_preds = 0;
982 struct postfix_elt *elt;
984 list_for_each_entry(elt, &ps->postfix, list) {
985 if (elt->op == OP_NONE)
988 if (elt->op == OP_AND || elt->op == OP_OR) {
995 if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
996 parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
1003 static int replace_preds(struct event_subsystem *system,
1004 struct ftrace_event_call *call,
1005 struct filter_parse_state *ps,
1006 char *filter_string)
1008 char *operand1 = NULL, *operand2 = NULL;
1009 struct filter_pred *pred;
1010 struct postfix_elt *elt;
1013 err = check_preds(ps);
1017 list_for_each_entry(elt, &ps->postfix, list) {
1018 if (elt->op == OP_NONE) {
1020 operand1 = elt->operand;
1022 operand2 = elt->operand;
1024 parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
1030 if (elt->op == OP_AND || elt->op == OP_OR) {
1031 pred = create_logical_pred(elt->op);
1033 err = filter_add_pred(ps, call, pred);
1034 filter_free_pred(pred);
1036 err = filter_add_subsystem_pred(ps, system,
1037 pred, filter_string);
1041 operand1 = operand2 = NULL;
1045 if (!operand1 || !operand2) {
1046 parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
1050 pred = create_pred(elt->op, operand1, operand2);
1052 err = filter_add_pred(ps, call, pred);
1053 filter_free_pred(pred);
1055 err = filter_add_subsystem_pred(ps, system, pred,
1060 operand1 = operand2 = NULL;
1066 int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
1070 struct filter_parse_state *ps;
1072 mutex_lock(&event_mutex);
1074 if (!strcmp(strstrip(filter_string), "0")) {
1075 filter_disable_preds(call);
1076 remove_filter_string(call->filter);
1077 mutex_unlock(&event_mutex);
1082 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1086 filter_disable_preds(call);
1087 replace_filter_string(call->filter, filter_string);
1089 parse_init(ps, filter_ops, filter_string);
1090 err = filter_parse(ps);
1092 append_filter_err(ps, call->filter);
1096 err = replace_preds(NULL, call, ps, filter_string);
1098 append_filter_err(ps, call->filter);
1101 filter_opstack_clear(ps);
1105 mutex_unlock(&event_mutex);
1110 int apply_subsystem_event_filter(struct event_subsystem *system,
1111 char *filter_string)
1115 struct filter_parse_state *ps;
1117 mutex_lock(&event_mutex);
1119 if (!strcmp(strstrip(filter_string), "0")) {
1120 filter_free_subsystem_preds(system);
1121 remove_filter_string(system->filter);
1122 mutex_unlock(&event_mutex);
1127 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1131 filter_free_subsystem_preds(system);
1132 replace_filter_string(system->filter, filter_string);
1134 parse_init(ps, filter_ops, filter_string);
1135 err = filter_parse(ps);
1137 append_filter_err(ps, system->filter);
1141 err = replace_preds(system, NULL, ps, filter_string);
1143 append_filter_err(ps, system->filter);
1146 filter_opstack_clear(ps);
1150 mutex_unlock(&event_mutex);