[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"

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);

/*
 * 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);
}
Commit	Line	Data
	1	/*
	2	* lttng-context.c
	3	*
	4	* LTTng trace/channel/event context management.
	5	*
	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
	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() */
	28	#include "lttng-events.h"
	29	#include "lttng-tracer.h"
	30
	31	int lttng_find_context(struct lttng_ctx ctx, const char name)
	32	{
	33	unsigned int i;
	34
	35	for (i = 0; i < ctx->nr_fields; i++) {
	36	/* Skip allocated (but non-initialized) contexts */
	37	if (!ctx->fields[i].event_field.name)
	38	continue;
	39	if (!strcmp(ctx->fields[i].event_field.name, name))
	40	return 1;
	41	}
	42	return 0;
	43	}
	44	EXPORT_SYMBOL_GPL(lttng_find_context);
	45
	46	/*
	47	* Note: as we append context information, the pointer location may change.
	48	*/
	49	struct lttng_ctx_field lttng_append_context(struct lttng_ctx *ctx_p)
	50	{
	51	struct lttng_ctx_field *field;
	52	struct lttng_ctx *ctx;
	53
	54	if (!*ctx_p) {
	55	*ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
	56	if (!*ctx_p)
	57	return NULL;
	58	(*ctx_p)->largest_align = 1;
	59	}
	60	ctx = *ctx_p;
	61	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
	62	struct lttng_ctx_field *new_fields;
	63
	64	ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
	65	new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
	66	if (!new_fields)
	67	return NULL;
	68	if (ctx->fields)
	69	memcpy(new_fields, ctx->fields, sizeof(ctx->fields) ctx->nr_fields);
	70	kfree(ctx->fields);
	71	ctx->fields = new_fields;
	72	}
	73	field = &ctx->fields[ctx->nr_fields];
	74	ctx->nr_fields++;
	75	return field;
	76	}
	77	EXPORT_SYMBOL_GPL(lttng_append_context);
	78
	79	/*
	80	* lttng_context_update() should be called at least once between context
	81	* modification and trace start.
	82	*/
	83	void lttng_context_update(struct lttng_ctx *ctx)
	84	{
	85	int i;
	86	size_t largest_align = 8; /* in bits */
	87
	88	for (i = 0; i < ctx->nr_fields; i++) {
	89	struct lttng_type *type;
	90	size_t field_align = 8;
	91
	92	type = &ctx->fields[i].event_field.type;
	93	switch (type->atype) {
	94	case atype_integer:
	95	field_align = type->u.basic.integer.alignment;
	96	break;
	97	case atype_array:
	98	{
	99	struct lttng_basic_type *btype;
	100
	101	btype = &type->u.array.elem_type;
	102	switch (btype->atype) {
	103	case atype_integer:
	104	field_align = btype->u.basic.integer.alignment;
	105	break;
	106	case atype_string:
	107	break;
	108
	109	case atype_array:
	110	case atype_sequence:
	111	default:
	112	WARN_ON_ONCE(1);
	113	break;
	114	}
	115	break;
	116	}
	117	case atype_sequence:
	118	{
	119	struct lttng_basic_type *btype;
	120
	121	btype = &type->u.sequence.length_type;
	122	switch (btype->atype) {
	123	case atype_integer:
	124	field_align = btype->u.basic.integer.alignment;
	125	break;
	126
	127	case atype_string:
	128	case atype_array:
	129	case atype_sequence:
	130	default:
	131	WARN_ON_ONCE(1);
	132	break;
	133	}
	134
	135	btype = &type->u.sequence.elem_type;
	136	switch (btype->atype) {
	137	case atype_integer:
	138	field_align = max_t(size_t,
	139	field_align,
	140	btype->u.basic.integer.alignment);
	141	break;
	142
	143	case atype_string:
	144	break;
	145
	146	case atype_array:
	147	case atype_sequence:
	148	default:
	149	WARN_ON_ONCE(1);
	150	break;
	151	}
	152	break;
	153	}
	154	case atype_string:
	155	break;
	156
	157	case atype_enum:
	158	default:
	159	WARN_ON_ONCE(1);
	160	break;
	161	}
	162	largest_align = max_t(size_t, largest_align, field_align);
	163	}
	164	ctx->largest_align = largest_align >> 3; /* bits to bytes */
	165	}
	166
	167	/*
	168	* Remove last context field.
	169	*/
	170	void lttng_remove_context_field(struct lttng_ctx **ctx_p,
	171	struct lttng_ctx_field *field)
	172	{
	173	struct lttng_ctx *ctx;
	174
	175	ctx = *ctx_p;
	176	ctx->nr_fields--;
	177	WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
	178	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
	179	}
	180	EXPORT_SYMBOL_GPL(lttng_remove_context_field);
	181
	182	void lttng_destroy_context(struct lttng_ctx *ctx)
	183	{
	184	int i;
	185
	186	if (!ctx)
	187	return;
	188	for (i = 0; i < ctx->nr_fields; i++) {
	189	if (ctx->fields[i].destroy)
	190	ctx->fields[i].destroy(&ctx->fields[i]);
	191	}
	192	kfree(ctx->fields);
	193	kfree(ctx);
	194	}