[lttng-modules.git] / lttng-context.c

/*
 * lttng-context.c
 *
 * LTTng trace/channel/event context management.
 *
 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include "wrapper/vmalloc.h"	/* for wrapper_vmalloc_sync_all() */
#include "lttng-events.h"
#include "lttng-tracer.h"

/*
 * The filter implementation requires that two consecutive "get" for the
 * same context performed by the same thread return the same result.
 */

/*
 * Static array of contexts, for $ctx filters.
 */
struct lttng_ctx *lttng_static_ctx;

int lttng_find_context(struct lttng_ctx *ctx, const char *name)
{
	unsigned int i;

	for (i = 0; i < ctx->nr_fields; i++) {
		/* Skip allocated (but non-initialized) contexts */
		if (!ctx->fields[i].event_field.name)
			continue;
		if (!strcmp(ctx->fields[i].event_field.name, name))
			return 1;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_find_context);

int lttng_get_context_index(struct lttng_ctx *ctx, const char *name)
{
	unsigned int i;

	if (!ctx)
		return -1;
	for (i = 0; i < ctx->nr_fields; i++) {
		/* Skip allocated (but non-initialized) contexts */
		if (!ctx->fields[i].event_field.name)
			continue;
		if (!strcmp(ctx->fields[i].event_field.name, name))
			return i;
	}
	return -1;
}
EXPORT_SYMBOL_GPL(lttng_get_context_index);

/*
 * Note: as we append context information, the pointer location may change.
 */
struct lttng_ctx_field *lttng_append_context(struct lttng_ctx **ctx_p)
{
	struct lttng_ctx_field *field;
	struct lttng_ctx *ctx;

	if (!*ctx_p) {
		*ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
		if (!*ctx_p)
			return NULL;
		(*ctx_p)->largest_align = 1;
	}
	ctx = *ctx_p;
	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
		struct lttng_ctx_field *new_fields;

		ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
		new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
		if (!new_fields)
			return NULL;
		if (ctx->fields)
			memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields);
		kfree(ctx->fields);
		ctx->fields = new_fields;
	}
	field = &ctx->fields[ctx->nr_fields];
	ctx->nr_fields++;
	return field;
}
EXPORT_SYMBOL_GPL(lttng_append_context);

/*
 * lttng_context_update() should be called at least once between context
 * modification and trace start.
 */
void lttng_context_update(struct lttng_ctx *ctx)
{
	int i;
	size_t largest_align = 8;	/* in bits */

	for (i = 0; i < ctx->nr_fields; i++) {
		struct lttng_type *type;
		size_t field_align = 8;

		type = &ctx->fields[i].event_field.type;
		switch (type->atype) {
		case atype_integer:
			field_align = type->u.basic.integer.alignment;
			break;
		case atype_array:
		{
			struct lttng_basic_type *btype;

			btype = &type->u.array.elem_type;
			switch (btype->atype) {
			case atype_integer:
				field_align = btype->u.basic.integer.alignment;
				break;
			case atype_string:
				break;

			case atype_array:
			case atype_sequence:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			break;
		}
		case atype_sequence:
		{
			struct lttng_basic_type *btype;

			btype = &type->u.sequence.length_type;
			switch (btype->atype) {
			case atype_integer:
				field_align = btype->u.basic.integer.alignment;
				break;

			case atype_string:
			case atype_array:
			case atype_sequence:
			default:
				WARN_ON_ONCE(1);
				break;
			}

			btype = &type->u.sequence.elem_type;
			switch (btype->atype) {
			case atype_integer:
				field_align = max_t(size_t,
					field_align,
					btype->u.basic.integer.alignment);
				break;

			case atype_string:
				break;

			case atype_array:
			case atype_sequence:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			break;
		}
		case atype_string:
			break;

		case atype_enum:
		default:
			WARN_ON_ONCE(1);
			break;
		}
		largest_align = max_t(size_t, largest_align, field_align);
	}
	ctx->largest_align = largest_align >> 3;	/* bits to bytes */
}

/*
 * Remove last context field.
 */
void lttng_remove_context_field(struct lttng_ctx **ctx_p,
				struct lttng_ctx_field *field)
{
	struct lttng_ctx *ctx;

	ctx = *ctx_p;
	ctx->nr_fields--;
	WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
}
EXPORT_SYMBOL_GPL(lttng_remove_context_field);

void lttng_destroy_context(struct lttng_ctx *ctx)
{
	int i;

	if (!ctx)
		return;
	for (i = 0; i < ctx->nr_fields; i++) {
		if (ctx->fields[i].destroy)
			ctx->fields[i].destroy(&ctx->fields[i]);
	}
	kfree(ctx->fields);
	kfree(ctx);
}

int lttng_context_init(void)
{
	int ret;

	ret = lttng_add_hostname_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_nice_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_pid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_pthread_id_to_ctx");
	}
	ret = lttng_add_ppid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_prio_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
	}
	ret = lttng_add_procname_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
	}
	ret = lttng_add_tid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_vppid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_vtid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_vpid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	/* TODO: perf counters for filtering */
	return 0;
}

void lttng_context_exit(void)
{
	lttng_destroy_context(lttng_static_ctx);
	lttng_static_ctx = NULL;
}
Commit	Line	Data
2dccf128	1	/*
a90917c3	2	* lttng-context.c
2dccf128	3	*
2dccf128	4	* LTTng trace/channel/event context management.
17baffe2	5	*
886d51a3 MD	6	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
2dccf128 MD	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/list.h>
	25	#include <linux/mutex.h>
	26	#include <linux/slab.h>
	27	#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
a90917c3 MD	28	#include "lttng-events.h"
a90917c3 MD	29	#include "lttng-tracer.h"
2dccf128	30
07dfc1d0 MD	31	/*
	32	* The filter implementation requires that two consecutive "get" for the
	33	* same context performed by the same thread return the same result.
	34	*/
	35
	36	/*
	37	* Static array of contexts, for $ctx filters.
	38	*/
	39	struct lttng_ctx *lttng_static_ctx;
	40
44252f0f MD	41	int lttng_find_context(struct lttng_ctx ctx, const char name)
	42	{
	43	unsigned int i;
	44
	45	for (i = 0; i < ctx->nr_fields; i++) {
4b58a8e4 MD	46	/* Skip allocated (but non-initialized) contexts */
	47	if (!ctx->fields[i].event_field.name)
	48	continue;
44252f0f MD	49	if (!strcmp(ctx->fields[i].event_field.name, name))
	50	return 1;
	51	}
	52	return 0;
	53	}
	54	EXPORT_SYMBOL_GPL(lttng_find_context);
	55
07dfc1d0 MD	56	int lttng_get_context_index(struct lttng_ctx ctx, const char name)
	57	{
	58	unsigned int i;
	59
	60	if (!ctx)
	61	return -1;
	62	for (i = 0; i < ctx->nr_fields; i++) {
	63	/* Skip allocated (but non-initialized) contexts */
	64	if (!ctx->fields[i].event_field.name)
	65	continue;
	66	if (!strcmp(ctx->fields[i].event_field.name, name))
	67	return i;
	68	}
	69	return -1;
	70	}
	71	EXPORT_SYMBOL_GPL(lttng_get_context_index);
	72
2001023e MD	73	/*
	74	* Note: as we append context information, the pointer location may change.
	75	*/
2dccf128 MD	76	struct lttng_ctx_field lttng_append_context(struct lttng_ctx *ctx_p)
	77	{
	78	struct lttng_ctx_field *field;
	79	struct lttng_ctx *ctx;
	80
	81	if (!*ctx_p) {
	82	*ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
	83	if (!*ctx_p)
	84	return NULL;
a9dd15da	85	(*ctx_p)->largest_align = 1;
2dccf128 MD	86	}
	87	ctx = *ctx_p;
	88	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
	89	struct lttng_ctx_field *new_fields;
	90
0f034e0f	91	ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
2dccf128 MD	92	new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
	93	if (!new_fields)
	94	return NULL;
	95	if (ctx->fields)
77aefe99	96	memcpy(new_fields, ctx->fields, sizeof(ctx->fields) ctx->nr_fields);
2dccf128 MD	97	kfree(ctx->fields);
	98	ctx->fields = new_fields;
	99	}
	100	field = &ctx->fields[ctx->nr_fields];
	101	ctx->nr_fields++;
	102	return field;
	103	}
	104	EXPORT_SYMBOL_GPL(lttng_append_context);
	105
a9dd15da MD	106	/*
	107	* lttng_context_update() should be called at least once between context
	108	* modification and trace start.
	109	*/
	110	void lttng_context_update(struct lttng_ctx *ctx)
	111	{
	112	int i;
	113	size_t largest_align = 8; /* in bits */
	114
	115	for (i = 0; i < ctx->nr_fields; i++) {
	116	struct lttng_type *type;
	117	size_t field_align = 8;
	118
	119	type = &ctx->fields[i].event_field.type;
	120	switch (type->atype) {
	121	case atype_integer:
	122	field_align = type->u.basic.integer.alignment;
	123	break;
	124	case atype_array:
	125	{
	126	struct lttng_basic_type *btype;
	127
	128	btype = &type->u.array.elem_type;
	129	switch (btype->atype) {
	130	case atype_integer:
	131	field_align = btype->u.basic.integer.alignment;
	132	break;
	133	case atype_string:
	134	break;
	135
	136	case atype_array:
	137	case atype_sequence:
	138	default:
	139	WARN_ON_ONCE(1);
	140	break;
	141	}
	142	break;
	143	}
	144	case atype_sequence:
	145	{
	146	struct lttng_basic_type *btype;
	147
	148	btype = &type->u.sequence.length_type;
	149	switch (btype->atype) {
	150	case atype_integer:
	151	field_align = btype->u.basic.integer.alignment;
	152	break;
	153
	154	case atype_string:
	155	case atype_array:
	156	case atype_sequence:
	157	default:
	158	WARN_ON_ONCE(1);
	159	break;
	160	}
	161
	162	btype = &type->u.sequence.elem_type;
	163	switch (btype->atype) {
	164	case atype_integer:
	165	field_align = max_t(size_t,
	166	field_align,
	167	btype->u.basic.integer.alignment);
	168	break;
	169
170	case atype_string:
171	break;
172
173	case atype_array:
174	case atype_sequence:
175	default:
176	WARN_ON_ONCE(1);
177	break;
178	}
179	break;
180	}
181	case atype_string:
182	break;
183
184	case atype_enum:
185	default:
186	WARN_ON_ONCE(1);
187	break;
188	}
189	largest_align = max_t(size_t, largest_align, field_align);
190	}
191	ctx->largest_align = largest_align >> 3; /* bits to bytes */
192	}
193
4cae220c MD	194	/*
	195	* Remove last context field.
	196	*/
8289661d MD	197	void lttng_remove_context_field(struct lttng_ctx **ctx_p,
	198	struct lttng_ctx_field *field)
	199	{
	200	struct lttng_ctx *ctx;
	201
	202	ctx = *ctx_p;
	203	ctx->nr_fields--;
4cae220c	204	WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
8289661d MD	205	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
	206	}
	207	EXPORT_SYMBOL_GPL(lttng_remove_context_field);
	208
2dccf128 MD	209	void lttng_destroy_context(struct lttng_ctx *ctx)
	210	{
	211	int i;
	212
8070f5c0 MD	213	if (!ctx)
8070f5c0 MD	214	return;
9e7e4892 MD	215	for (i = 0; i < ctx->nr_fields; i++) {
	216	if (ctx->fields[i].destroy)
	217	ctx->fields[i].destroy(&ctx->fields[i]);
	218	}
2dccf128 MD	219	kfree(ctx->fields);
	220	kfree(ctx);
	221	}
07dfc1d0 MD	222
	223	int lttng_context_init(void)
	224	{
	225	int ret;
	226
f127e61e MD	227	ret = lttng_add_hostname_to_ctx(&lttng_static_ctx);
	228	if (ret) {
	229	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	230	}
	231	ret = lttng_add_nice_to_ctx(&lttng_static_ctx);
07dfc1d0 MD	232	if (ret) {
	233	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	234	}
07dfc1d0 MD	235	ret = lttng_add_pid_to_ctx(&lttng_static_ctx);
	236	if (ret) {
	237	printk(KERN_WARNING "Cannot add context lttng_add_pthread_id_to_ctx");
	238	}
f127e61e	239	ret = lttng_add_ppid_to_ctx(&lttng_static_ctx);
07dfc1d0	240	if (ret) {
f127e61e	241	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
07dfc1d0 MD	242	}
	243	ret = lttng_add_prio_to_ctx(&lttng_static_ctx);
	244	if (ret) {
	245	printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
	246	}
f127e61e	247	ret = lttng_add_procname_to_ctx(&lttng_static_ctx);
07dfc1d0	248	if (ret) {
f127e61e	249	printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
07dfc1d0 MD	250	}
	251	ret = lttng_add_tid_to_ctx(&lttng_static_ctx);
	252	if (ret) {
	253	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	254	}
f127e61e	255	ret = lttng_add_vppid_to_ctx(&lttng_static_ctx);
07dfc1d0 MD	256	if (ret) {
	257	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	258	}
f127e61e	259	ret = lttng_add_vtid_to_ctx(&lttng_static_ctx);
07dfc1d0 MD	260	if (ret) {
	261	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	262	}
f127e61e	263	ret = lttng_add_vpid_to_ctx(&lttng_static_ctx);
07dfc1d0 MD	264	if (ret) {
	265	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	266	}
f127e61e	267	/* TODO: perf counters for filtering */
07dfc1d0 MD	268	return 0;
	269	}
	270
	271	void lttng_context_exit(void)
	272	{
	273	lttng_destroy_context(lttng_static_ctx);
	274	lttng_static_ctx = NULL;
	275	}