[deliverable/linux.git] / kernel / trace / trace_events_filter.c

/*
 * trace_events_filter - generic event filtering
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
 */

#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/ctype.h>

#include "trace.h"
#include "trace_output.h"

static int filter_pred_64(struct filter_pred *pred, void *event)
{
	u64 *addr = (u64 *)(event + pred->offset);
	u64 val = (u64)pred->val;
	int match;

	match = (val == *addr) ^ pred->not;

	return match;
}

static int filter_pred_32(struct filter_pred *pred, void *event)
{
	u32 *addr = (u32 *)(event + pred->offset);
	u32 val = (u32)pred->val;
	int match;

	match = (val == *addr) ^ pred->not;

	return match;
}

static int filter_pred_16(struct filter_pred *pred, void *event)
{
	u16 *addr = (u16 *)(event + pred->offset);
	u16 val = (u16)pred->val;
	int match;

	match = (val == *addr) ^ pred->not;

	return match;
}

static int filter_pred_8(struct filter_pred *pred, void *event)
{
	u8 *addr = (u8 *)(event + pred->offset);
	u8 val = (u8)pred->val;
	int match;

	match = (val == *addr) ^ pred->not;

	return match;
}

static int filter_pred_string(struct filter_pred *pred, void *event)
{
	char *addr = (char *)(event + pred->offset);
	int cmp, match;

	cmp = strncmp(addr, pred->str_val, pred->str_len);

	match = (!cmp) ^ pred->not;

	return match;
}

/* return 1 if event matches, 0 otherwise (discard) */
int filter_match_preds(struct ftrace_event_call *call, void *rec)
{
	int i, matched, and_failed = 0;
	struct filter_pred *pred;

	for (i = 0; i < MAX_FILTER_PRED; i++) {
		if (call->preds[i]) {
			pred = call->preds[i];
			if (and_failed && !pred->or)
				continue;
			matched = pred->fn(pred, rec);
			if (!matched && !pred->or) {
				and_failed = 1;
				continue;
			} else if (matched && pred->or)
				return 1;
		} else
			break;
	}

	if (and_failed)
		return 0;

	return 1;
}

void filter_print_preds(struct filter_pred **preds, struct trace_seq *s)
{
	char *field_name;
	struct filter_pred *pred;
	int i;

	if (!preds) {
		trace_seq_printf(s, "none\n");
		return;
	}

	for (i = 0; i < MAX_FILTER_PRED; i++) {
		if (preds[i]) {
			pred = preds[i];
			field_name = pred->field_name;
			if (i)
				trace_seq_printf(s, pred->or ? "|| " : "&& ");
			trace_seq_printf(s, "%s ", field_name);
			trace_seq_printf(s, pred->not ? "!= " : "== ");
			if (pred->str_val)
				trace_seq_printf(s, "%s\n", pred->str_val);
			else
				trace_seq_printf(s, "%llu\n", pred->val);
		} else
			break;
	}
}

static struct ftrace_event_field *
find_event_field(struct ftrace_event_call *call, char *name)
{
	struct ftrace_event_field *field;

	list_for_each_entry(field, &call->fields, link) {
		if (!strcmp(field->name, name))
			return field;
	}

	return NULL;
}

void filter_free_pred(struct filter_pred *pred)
{
	if (!pred)
		return;

	kfree(pred->field_name);
	kfree(pred->str_val);
	kfree(pred);
}

void filter_free_preds(struct ftrace_event_call *call)
{
	int i;

	if (call->preds) {
		for (i = 0; i < MAX_FILTER_PRED; i++)
			filter_free_pred(call->preds[i]);
		kfree(call->preds);
		call->preds = NULL;
	}
}

void filter_free_subsystem_preds(struct event_subsystem *system)
{
	struct ftrace_event_call *call = __start_ftrace_events;
	int i;

	if (system->preds) {
		for (i = 0; i < MAX_FILTER_PRED; i++)
			filter_free_pred(system->preds[i]);
		kfree(system->preds);
		system->preds = NULL;
	}

	events_for_each(call) {
		if (!call->name || !call->regfunc)
			continue;

		if (!strcmp(call->system, system->name))
			filter_free_preds(call);
	}
}

static int __filter_add_pred(struct ftrace_event_call *call,
			     struct filter_pred *pred)
{
	int i;

	if (call->preds && !pred->compound)
		filter_free_preds(call);

	if (!call->preds) {
		call->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
				      GFP_KERNEL);
		if (!call->preds)
			return -ENOMEM;
	}

	for (i = 0; i < MAX_FILTER_PRED; i++) {
		if (!call->preds[i]) {
			call->preds[i] = pred;
			return 0;
		}
	}

	return -ENOSPC;
}

static int is_string_field(const char *type)
{
	if (strchr(type, '[') && strstr(type, "char"))
		return 1;

	return 0;
}

int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
{
	struct ftrace_event_field *field;

	field = find_event_field(call, pred->field_name);
	if (!field)
		return -EINVAL;

	pred->offset = field->offset;

	if (is_string_field(field->type)) {
		if (!pred->str_val)
			return -EINVAL;
		pred->fn = filter_pred_string;
		pred->str_len = field->size;
		return __filter_add_pred(call, pred);
	} else {
		if (pred->str_val)
			return -EINVAL;
	}

	switch (field->size) {
	case 8:
		pred->fn = filter_pred_64;
		break;
	case 4:
		pred->fn = filter_pred_32;
		break;
	case 2:
		pred->fn = filter_pred_16;
		break;
	case 1:
		pred->fn = filter_pred_8;
		break;
	default:
		return -EINVAL;
	}

	return __filter_add_pred(call, pred);
}

static struct filter_pred *copy_pred(struct filter_pred *pred)
{
	struct filter_pred *new_pred = kmalloc(sizeof(*pred), GFP_KERNEL);
	if (!new_pred)
		return NULL;

	memcpy(new_pred, pred, sizeof(*pred));

	if (pred->field_name) {
		new_pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
		if (!new_pred->field_name) {
			kfree(new_pred);
			return NULL;
		}
	}

	if (pred->str_val) {
		new_pred->str_val = kstrdup(pred->str_val, GFP_KERNEL);
		if (!new_pred->str_val) {
			filter_free_pred(new_pred);
			return NULL;
		}
	}

	return new_pred;
}

int filter_add_subsystem_pred(struct event_subsystem *system,
			      struct filter_pred *pred)
{
	struct ftrace_event_call *call = __start_ftrace_events;
	struct filter_pred *event_pred;
	int i;

	if (system->preds && !pred->compound)
		filter_free_subsystem_preds(system);

	if (!system->preds) {
		system->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
					GFP_KERNEL);
		if (!system->preds)
			return -ENOMEM;
	}

	for (i = 0; i < MAX_FILTER_PRED; i++) {
		if (!system->preds[i]) {
			system->preds[i] = pred;
			break;
		}
	}

	if (i == MAX_FILTER_PRED)
		return -ENOSPC;

	events_for_each(call) {
		int err;

		if (!call->name || !call->regfunc)
			continue;

		if (strcmp(call->system, system->name))
			continue;

		if (!find_event_field(call, pred->field_name))
			continue;

		event_pred = copy_pred(pred);
		if (!event_pred)
			goto oom;

		err = filter_add_pred(call, event_pred);
		if (err)
			filter_free_pred(event_pred);
		if (err == -ENOMEM)
			goto oom;
	}

	return 0;

oom:
	system->preds[i] = NULL;
	return -ENOMEM;
}

int filter_parse(char **pbuf, struct filter_pred *pred)
{
	char *tmp, *tok, *val_str = NULL;
	int tok_n = 0;

	/* field ==/!= number, or/and field ==/!= number, number */
	while ((tok = strsep(pbuf, " \n"))) {
		if (tok_n == 0) {
			if (!strcmp(tok, "0")) {
				pred->clear = 1;
				return 0;
			} else if (!strcmp(tok, "&&")) {
				pred->or = 0;
				pred->compound = 1;
			} else if (!strcmp(tok, "||")) {
				pred->or = 1;
				pred->compound = 1;
			} else
				pred->field_name = tok;
			tok_n = 1;
			continue;
		}
		if (tok_n == 1) {
			if (!pred->field_name)
				pred->field_name = tok;
			else if (!strcmp(tok, "!="))
				pred->not = 1;
			else if (!strcmp(tok, "=="))
				pred->not = 0;
			else {
				pred->field_name = NULL;
				return -EINVAL;
			}
			tok_n = 2;
			continue;
		}
		if (tok_n == 2) {
			if (pred->compound) {
				if (!strcmp(tok, "!="))
					pred->not = 1;
				else if (!strcmp(tok, "=="))
					pred->not = 0;
				else {
					pred->field_name = NULL;
					return -EINVAL;
				}
			} else {
				val_str = tok;
				break; /* done */
			}
			tok_n = 3;
			continue;
		}
		if (tok_n == 3) {
			val_str = tok;
			break; /* done */
		}
	}

	if (!val_str) {
		pred->field_name = NULL;
		return -EINVAL;
	}

	pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
	if (!pred->field_name)
		return -ENOMEM;

	pred->val = simple_strtoull(val_str, &tmp, 0);
	if (tmp == val_str) {
		pred->str_val = kstrdup(val_str, GFP_KERNEL);
		if (!pred->str_val)
			return -ENOMEM;
	} else if (*tmp != '\0')
		return -EINVAL;

	return 0;
}
Commit	Line	Data
7ce7e424 TZ	1	/*
	2	* trace_events_filter - generic event filtering
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	17	*
	18	* Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
	19	*/
	20
	21	#include <linux/debugfs.h>
	22	#include <linux/uaccess.h>
	23	#include <linux/module.h>
	24	#include <linux/ctype.h>
	25
	26	#include "trace.h"
4bda2d51	27	#include "trace_output.h"
7ce7e424 TZ	28
	29	static int filter_pred_64(struct filter_pred pred, void event)
	30	{
	31	u64 addr = (u64 )(event + pred->offset);
	32	u64 val = (u64)pred->val;
	33	int match;
	34
	35	match = (val == *addr) ^ pred->not;
	36
	37	return match;
	38	}
	39
	40	static int filter_pred_32(struct filter_pred pred, void event)
	41	{
	42	u32 addr = (u32 )(event + pred->offset);
	43	u32 val = (u32)pred->val;
	44	int match;
	45
	46	match = (val == *addr) ^ pred->not;
	47
	48	return match;
	49	}
	50
	51	static int filter_pred_16(struct filter_pred pred, void event)
	52	{
	53	u16 addr = (u16 )(event + pred->offset);
	54	u16 val = (u16)pred->val;
	55	int match;
	56
	57	match = (val == *addr) ^ pred->not;
	58
	59	return match;
	60	}
	61
	62	static int filter_pred_8(struct filter_pred pred, void event)
	63	{
	64	u8 addr = (u8 )(event + pred->offset);
	65	u8 val = (u8)pred->val;
	66	int match;
	67
	68	match = (val == *addr) ^ pred->not;
	69
	70	return match;
	71	}
	72
	73	static int filter_pred_string(struct filter_pred pred, void event)
	74	{
	75	char addr = (char )(event + pred->offset);
	76	int cmp, match;
	77
	78	cmp = strncmp(addr, pred->str_val, pred->str_len);
	79
	80	match = (!cmp) ^ pred->not;
	81
	82	return match;
	83	}
	84
	85	/* return 1 if event matches, 0 otherwise (discard) */
	86	int filter_match_preds(struct ftrace_event_call call, void rec)
	87	{
	88	int i, matched, and_failed = 0;
	89	struct filter_pred *pred;
	90
	91	for (i = 0; i < MAX_FILTER_PRED; i++) {
92	if (call->preds[i]) {
93	pred = call->preds[i];
94	if (and_failed && !pred->or)
95	continue;
96	matched = pred->fn(pred, rec);
97	if (!matched && !pred->or) {
98	and_failed = 1;
99	continue;
100	} else if (matched && pred->or)
101	return 1;
102	} else
103	break;
104	}
105
106	if (and_failed)
107	return 0;
108
109	return 1;
110	}
111
4bda2d51	112	void filter_print_preds(struct filter_pred *preds, struct trace_seq s)
7ce7e424	113	{
7ce7e424 TZ	114	char *field_name;
	115	struct filter_pred *pred;
	116	int i;
	117
	118	if (!preds) {
4bda2d51 TZ	119	trace_seq_printf(s, "none\n");
4bda2d51 TZ	120	return;
7ce7e424 TZ	121	}
	122
	123	for (i = 0; i < MAX_FILTER_PRED; i++) {
	124	if (preds[i]) {
	125	pred = preds[i];
	126	field_name = pred->field_name;
	127	if (i)
4bda2d51 TZ	128	trace_seq_printf(s, pred->or ? "\|\| " : "&& ");
	129	trace_seq_printf(s, "%s ", field_name);
	130	trace_seq_printf(s, pred->not ? "!= " : "== ");
7ce7e424	131	if (pred->str_val)
4bda2d51	132	trace_seq_printf(s, "%s\n", pred->str_val);
7ce7e424	133	else
4bda2d51	134	trace_seq_printf(s, "%llu\n", pred->val);
7ce7e424 TZ	135	} else
	136	break;
	137	}
7ce7e424 TZ	138	}
	139
	140	static struct ftrace_event_field *
	141	find_event_field(struct ftrace_event_call call, char name)
	142	{
1fc2d5c1	143	struct ftrace_event_field *field;
7ce7e424	144
1fc2d5c1	145	list_for_each_entry(field, &call->fields, link) {
7ce7e424 TZ	146	if (!strcmp(field->name, name))
	147	return field;
	148	}
	149
	150	return NULL;
	151	}
	152
	153	void filter_free_pred(struct filter_pred *pred)
	154	{
	155	if (!pred)
	156	return;
	157
	158	kfree(pred->field_name);
	159	kfree(pred->str_val);
	160	kfree(pred);
	161	}
	162
	163	void filter_free_preds(struct ftrace_event_call *call)
	164	{
	165	int i;
	166
	167	if (call->preds) {
	168	for (i = 0; i < MAX_FILTER_PRED; i++)
	169	filter_free_pred(call->preds[i]);
	170	kfree(call->preds);
	171	call->preds = NULL;
	172	}
	173	}
	174
cfb180f3 TZ	175	void filter_free_subsystem_preds(struct event_subsystem *system)
	176	{
	177	struct ftrace_event_call *call = __start_ftrace_events;
	178	int i;
	179
	180	if (system->preds) {
	181	for (i = 0; i < MAX_FILTER_PRED; i++)
	182	filter_free_pred(system->preds[i]);
	183	kfree(system->preds);
	184	system->preds = NULL;
	185	}
	186
	187	events_for_each(call) {
	188	if (!call->name \|\| !call->regfunc)
	189	continue;
	190
	191	if (!strcmp(call->system, system->name))
	192	filter_free_preds(call);
	193	}
	194	}
	195
7ce7e424 TZ	196	static int __filter_add_pred(struct ftrace_event_call *call,
	197	struct filter_pred *pred)
	198	{
	199	int i;
	200
	201	if (call->preds && !pred->compound)
	202	filter_free_preds(call);
	203
	204	if (!call->preds) {
	205	call->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
	206	GFP_KERNEL);
	207	if (!call->preds)
	208	return -ENOMEM;
	209	}
	210
	211	for (i = 0; i < MAX_FILTER_PRED; i++) {
	212	if (!call->preds[i]) {
	213	call->preds[i] = pred;
	214	return 0;
	215	}
	216	}
	217
44e9c8b7	218	return -ENOSPC;
7ce7e424 TZ	219	}
	220
	221	static int is_string_field(const char *type)
	222	{
	223	if (strchr(type, '[') && strstr(type, "char"))
	224	return 1;
	225
	226	return 0;
	227	}
	228
	229	int filter_add_pred(struct ftrace_event_call call, struct filter_pred pred)
	230	{
	231	struct ftrace_event_field *field;
	232
	233	field = find_event_field(call, pred->field_name);
	234	if (!field)
	235	return -EINVAL;
	236
	237	pred->offset = field->offset;
	238
	239	if (is_string_field(field->type)) {
9f58a159 TZ	240	if (!pred->str_val)
9f58a159 TZ	241	return -EINVAL;
7ce7e424 TZ	242	pred->fn = filter_pred_string;
	243	pred->str_len = field->size;
	244	return __filter_add_pred(call, pred);
9f58a159 TZ	245	} else {
	246	if (pred->str_val)
	247	return -EINVAL;
7ce7e424 TZ	248	}
	249
	250	switch (field->size) {
	251	case 8:
	252	pred->fn = filter_pred_64;
	253	break;
	254	case 4:
	255	pred->fn = filter_pred_32;
	256	break;
	257	case 2:
	258	pred->fn = filter_pred_16;
	259	break;
	260	case 1:
	261	pred->fn = filter_pred_8;
	262	break;
	263	default:
	264	return -EINVAL;
	265	}
	266
	267	return __filter_add_pred(call, pred);
	268	}
	269
cfb180f3 TZ	270	static struct filter_pred copy_pred(struct filter_pred pred)
	271	{
	272	struct filter_pred new_pred = kmalloc(sizeof(pred), GFP_KERNEL);
	273	if (!new_pred)
	274	return NULL;
	275
	276	memcpy(new_pred, pred, sizeof(*pred));
ee6cdabc TZ	277
	278	if (pred->field_name) {
	279	new_pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
	280	if (!new_pred->field_name) {
	281	kfree(new_pred);
	282	return NULL;
	283	}
	284	}
	285
cfb180f3 TZ	286	if (pred->str_val) {
cfb180f3 TZ	287	new_pred->str_val = kstrdup(pred->str_val, GFP_KERNEL);
cfb180f3	288	if (!new_pred->str_val) {
ee6cdabc	289	filter_free_pred(new_pred);
cfb180f3 TZ	290	return NULL;
	291	}
	292	}
	293
	294	return new_pred;
	295	}
	296
	297	int filter_add_subsystem_pred(struct event_subsystem *system,
	298	struct filter_pred *pred)
	299	{
	300	struct ftrace_event_call *call = __start_ftrace_events;
	301	struct filter_pred *event_pred;
	302	int i;
	303
	304	if (system->preds && !pred->compound)
	305	filter_free_subsystem_preds(system);
	306
	307	if (!system->preds) {
	308	system->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
	309	GFP_KERNEL);
	310	if (!system->preds)
	311	return -ENOMEM;
	312	}
	313
	314	for (i = 0; i < MAX_FILTER_PRED; i++) {
	315	if (!system->preds[i]) {
	316	system->preds[i] = pred;
	317	break;
	318	}
cfb180f3 TZ	319	}
cfb180f3 TZ	320
c4cff064	321	if (i == MAX_FILTER_PRED)
44e9c8b7	322	return -ENOSPC;
c4cff064	323
cfb180f3	324	events_for_each(call) {
c4cff064 TZ	325	int err;
c4cff064 TZ	326
cfb180f3 TZ	327	if (!call->name \|\| !call->regfunc)
	328	continue;
	329
c4cff064 TZ	330	if (strcmp(call->system, system->name))
	331	continue;
	332
	333	if (!find_event_field(call, pred->field_name))
	334	continue;
	335
	336	event_pred = copy_pred(pred);
	337	if (!event_pred)
	338	goto oom;
	339
	340	err = filter_add_pred(call, event_pred);
	341	if (err)
	342	filter_free_pred(event_pred);
	343	if (err == -ENOMEM)
	344	goto oom;
cfb180f3 TZ	345	}
	346
	347	return 0;
c4cff064 TZ	348
	349	oom:
	350	system->preds[i] = NULL;
	351	return -ENOMEM;
cfb180f3 TZ	352	}
cfb180f3 TZ	353
7ce7e424 TZ	354	int filter_parse(char *pbuf, struct filter_pred pred)
	355	{
	356	char tmp, tok, *val_str = NULL;
	357	int tok_n = 0;
	358
	359	/* field ==/!= number, or/and field ==/!= number, number */
	360	while ((tok = strsep(pbuf, " \n"))) {
	361	if (tok_n == 0) {
	362	if (!strcmp(tok, "0")) {
	363	pred->clear = 1;
	364	return 0;
	365	} else if (!strcmp(tok, "&&")) {
	366	pred->or = 0;
	367	pred->compound = 1;
	368	} else if (!strcmp(tok, "\|\|")) {
	369	pred->or = 1;
	370	pred->compound = 1;
	371	} else
	372	pred->field_name = tok;
	373	tok_n = 1;
	374	continue;
	375	}
	376	if (tok_n == 1) {
	377	if (!pred->field_name)
	378	pred->field_name = tok;
	379	else if (!strcmp(tok, "!="))
	380	pred->not = 1;
	381	else if (!strcmp(tok, "=="))
	382	pred->not = 0;
	383	else {
	384	pred->field_name = NULL;
	385	return -EINVAL;
	386	}
	387	tok_n = 2;
	388	continue;
	389	}
	390	if (tok_n == 2) {
	391	if (pred->compound) {
	392	if (!strcmp(tok, "!="))
	393	pred->not = 1;
	394	else if (!strcmp(tok, "=="))
	395	pred->not = 0;
	396	else {
	397	pred->field_name = NULL;
	398	return -EINVAL;
	399	}
	400	} else {
	401	val_str = tok;
	402	break; /* done */
	403	}
	404	tok_n = 3;
	405	continue;
	406	}
	407	if (tok_n == 3) {
	408	val_str = tok;
	409	break; /* done */
	410	}
	411	}
	412
bcabd91c LZ	413	if (!val_str) {
	414	pred->field_name = NULL;
	415	return -EINVAL;
	416	}
	417
7ce7e424 TZ	418	pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
	419	if (!pred->field_name)
	420	return -ENOMEM;
	421
a3e0ab05	422	pred->val = simple_strtoull(val_str, &tmp, 0);
7ce7e424 TZ	423	if (tmp == val_str) {
	424	pred->str_val = kstrdup(val_str, GFP_KERNEL);
	425	if (!pred->str_val)
	426	return -ENOMEM;
a3e0ab05 LZ	427	} else if (*tmp != '\0')
a3e0ab05 LZ	428	return -EINVAL;
7ce7e424 TZ	429
	430	return 0;
	431	}
	432
	433