[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;
	const char *subname;

	if (!ctx)
		return -1;
	if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
		subname = name + strlen("$ctx.");
	} else {
		subname = name;
	}
	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, subname))
			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_hostname_to_ctx");
	}
	ret = lttng_add_nice_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_nice_to_ctx");
	}
	ret = lttng_add_pid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_pid_to_ctx");
	}
	ret = lttng_add_ppid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_ppid_to_ctx");
	}
	ret = lttng_add_prio_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_prio_to_ctx");
	}
	ret = lttng_add_procname_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
	}
	ret = lttng_add_tid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_tid_to_ctx");
	}
	ret = lttng_add_vppid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_vppid_to_ctx");
	}
	ret = lttng_add_vtid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
	}
	ret = lttng_add_vpid_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
	}
	ret = lttng_add_cpu_id_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_cpu_id_to_ctx");
	}
	ret = lttng_add_interruptible_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_interruptible_to_ctx");
	}
	ret = lttng_add_need_reschedule_to_ctx(&lttng_static_ctx);
	if (ret) {
		printk(KERN_WARNING "Cannot add context lttng_add_need_reschedule_to_ctx");
	}
	ret = lttng_add_preemptible_to_ctx(&lttng_static_ctx);
	if (ret && ret != -ENOSYS) {
		printk(KERN_WARNING "Cannot add context lttng_add_preemptible_to_ctx");
	}
	ret = lttng_add_migratable_to_ctx(&lttng_static_ctx);
	if (ret && ret != -ENOSYS) {
		printk(KERN_WARNING "Cannot add context lttng_add_migratable_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>
241ae9a8 MD	27	#include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_all() */
	28	#include <lttng-events.h>
	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 $ctx filters.
	38	*/
	39	struct lttng_ctx *lttng_static_ctx;
	40
44252f0f MD	41	int lttng_find_context(struct lttng_ctx ctx, const char name)
	42	{
	43	unsigned int i;
	44
	45	for (i = 0; i < ctx->nr_fields; i++) {
4b58a8e4 MD	46	/* Skip allocated (but non-initialized) contexts */
	47	if (!ctx->fields[i].event_field.name)
	48	continue;
44252f0f MD	49	if (!strcmp(ctx->fields[i].event_field.name, name))
	50	return 1;
	51	}
	52	return 0;
	53	}
	54	EXPORT_SYMBOL_GPL(lttng_find_context);
	55
07dfc1d0 MD	56	int lttng_get_context_index(struct lttng_ctx ctx, const char name)
	57	{
	58	unsigned int i;
0451bcec	59	const char *subname;
07dfc1d0 MD	60
	61	if (!ctx)
	62	return -1;
0451bcec MD	63	if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
	64	subname = name + strlen("$ctx.");
	65	} else {
	66	subname = name;
	67	}
07dfc1d0 MD	68	for (i = 0; i < ctx->nr_fields; i++) {
	69	/* Skip allocated (but non-initialized) contexts */
	70	if (!ctx->fields[i].event_field.name)
	71	continue;
0451bcec	72	if (!strcmp(ctx->fields[i].event_field.name, subname))
07dfc1d0 MD	73	return i;
	74	}
	75	return -1;
	76	}
	77	EXPORT_SYMBOL_GPL(lttng_get_context_index);
	78
2001023e MD	79	/*
	80	* Note: as we append context information, the pointer location may change.
	81	*/
2dccf128 MD	82	struct lttng_ctx_field lttng_append_context(struct lttng_ctx *ctx_p)
	83	{
	84	struct lttng_ctx_field *field;
	85	struct lttng_ctx *ctx;
	86
	87	if (!*ctx_p) {
	88	*ctx_p = kzalloc(sizeof(struct lttng_ctx), GFP_KERNEL);
	89	if (!*ctx_p)
	90	return NULL;
a9dd15da	91	(*ctx_p)->largest_align = 1;
2dccf128 MD	92	}
	93	ctx = *ctx_p;
	94	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
	95	struct lttng_ctx_field *new_fields;
	96
0f034e0f	97	ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
2dccf128 MD	98	new_fields = kzalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field), GFP_KERNEL);
	99	if (!new_fields)
	100	return NULL;
	101	if (ctx->fields)
77aefe99	102	memcpy(new_fields, ctx->fields, sizeof(ctx->fields) ctx->nr_fields);
2dccf128 MD	103	kfree(ctx->fields);
	104	ctx->fields = new_fields;
	105	}
	106	field = &ctx->fields[ctx->nr_fields];
	107	ctx->nr_fields++;
	108	return field;
	109	}
	110	EXPORT_SYMBOL_GPL(lttng_append_context);
	111
a9dd15da MD	112	/*
	113	* lttng_context_update() should be called at least once between context
	114	* modification and trace start.
	115	*/
	116	void lttng_context_update(struct lttng_ctx *ctx)
	117	{
	118	int i;
	119	size_t largest_align = 8; /* in bits */
	120
	121	for (i = 0; i < ctx->nr_fields; i++) {
	122	struct lttng_type *type;
	123	size_t field_align = 8;
	124
	125	type = &ctx->fields[i].event_field.type;
	126	switch (type->atype) {
	127	case atype_integer:
	128	field_align = type->u.basic.integer.alignment;
	129	break;
	130	case atype_array:
	131	{
	132	struct lttng_basic_type *btype;
	133
	134	btype = &type->u.array.elem_type;
	135	switch (btype->atype) {
	136	case atype_integer:
	137	field_align = btype->u.basic.integer.alignment;
	138	break;
	139	case atype_string:
	140	break;
	141
	142	case atype_array:
	143	case atype_sequence:
	144	default:
	145	WARN_ON_ONCE(1);
	146	break;
	147	}
	148	break;
	149	}
	150	case atype_sequence:
	151	{
	152	struct lttng_basic_type *btype;
	153
	154	btype = &type->u.sequence.length_type;
	155	switch (btype->atype) {
	156	case atype_integer:
	157	field_align = btype->u.basic.integer.alignment;
	158	break;
	159
	160	case atype_string:
	161	case atype_array:
	162	case atype_sequence:
	163	default:
	164	WARN_ON_ONCE(1);
	165	break;
	166	}
	167
	168	btype = &type->u.sequence.elem_type;
	169	switch (btype->atype) {
	170	case atype_integer:
	171	field_align = max_t(size_t,
	172	field_align,
	173	btype->u.basic.integer.alignment);
	174	break;
	175
176	case atype_string:
177	break;
178
179	case atype_array:
180	case atype_sequence:
181	default:
182	WARN_ON_ONCE(1);
183	break;
184	}
185	break;
186	}
187	case atype_string:
188	break;
189
190	case atype_enum:
191	default:
192	WARN_ON_ONCE(1);
193	break;
194	}
195	largest_align = max_t(size_t, largest_align, field_align);
196	}
197	ctx->largest_align = largest_align >> 3; /* bits to bytes */
198	}
199
4cae220c MD	200	/*
	201	* Remove last context field.
	202	*/
8289661d MD	203	void lttng_remove_context_field(struct lttng_ctx **ctx_p,
	204	struct lttng_ctx_field *field)
	205	{
	206	struct lttng_ctx *ctx;
	207
	208	ctx = *ctx_p;
	209	ctx->nr_fields--;
4cae220c	210	WARN_ON_ONCE(&ctx->fields[ctx->nr_fields] != field);
8289661d MD	211	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
	212	}
	213	EXPORT_SYMBOL_GPL(lttng_remove_context_field);
	214
2dccf128 MD	215	void lttng_destroy_context(struct lttng_ctx *ctx)
	216	{
	217	int i;
	218
8070f5c0 MD	219	if (!ctx)
8070f5c0 MD	220	return;
9e7e4892 MD	221	for (i = 0; i < ctx->nr_fields; i++) {
	222	if (ctx->fields[i].destroy)
	223	ctx->fields[i].destroy(&ctx->fields[i]);
	224	}
2dccf128 MD	225	kfree(ctx->fields);
	226	kfree(ctx);
	227	}
07dfc1d0 MD	228
	229	int lttng_context_init(void)
	230	{
	231	int ret;
	232
f127e61e MD	233	ret = lttng_add_hostname_to_ctx(&lttng_static_ctx);
f127e61e MD	234	if (ret) {
38c4a82c	235	printk(KERN_WARNING "Cannot add context lttng_add_hostname_to_ctx");
f127e61e MD	236	}
f127e61e MD	237	ret = lttng_add_nice_to_ctx(&lttng_static_ctx);
07dfc1d0	238	if (ret) {
38c4a82c	239	printk(KERN_WARNING "Cannot add context lttng_add_nice_to_ctx");
07dfc1d0	240	}
07dfc1d0 MD	241	ret = lttng_add_pid_to_ctx(&lttng_static_ctx);
07dfc1d0 MD	242	if (ret) {
38c4a82c	243	printk(KERN_WARNING "Cannot add context lttng_add_pid_to_ctx");
07dfc1d0	244	}
f127e61e	245	ret = lttng_add_ppid_to_ctx(&lttng_static_ctx);
07dfc1d0	246	if (ret) {
38c4a82c	247	printk(KERN_WARNING "Cannot add context lttng_add_ppid_to_ctx");
07dfc1d0 MD	248	}
	249	ret = lttng_add_prio_to_ctx(&lttng_static_ctx);
	250	if (ret) {
38c4a82c	251	printk(KERN_WARNING "Cannot add context lttng_add_prio_to_ctx");
07dfc1d0	252	}
f127e61e	253	ret = lttng_add_procname_to_ctx(&lttng_static_ctx);
07dfc1d0	254	if (ret) {
38c4a82c	255	printk(KERN_WARNING "Cannot add context lttng_add_procname_to_ctx");
07dfc1d0 MD	256	}
	257	ret = lttng_add_tid_to_ctx(&lttng_static_ctx);
	258	if (ret) {
38c4a82c	259	printk(KERN_WARNING "Cannot add context lttng_add_tid_to_ctx");
07dfc1d0	260	}
f127e61e	261	ret = lttng_add_vppid_to_ctx(&lttng_static_ctx);
07dfc1d0	262	if (ret) {
38c4a82c	263	printk(KERN_WARNING "Cannot add context lttng_add_vppid_to_ctx");
07dfc1d0	264	}
f127e61e	265	ret = lttng_add_vtid_to_ctx(&lttng_static_ctx);
07dfc1d0	266	if (ret) {
38c4a82c	267	printk(KERN_WARNING "Cannot add context lttng_add_vtid_to_ctx");
07dfc1d0	268	}
f127e61e	269	ret = lttng_add_vpid_to_ctx(&lttng_static_ctx);
07dfc1d0	270	if (ret) {
38c4a82c	271	printk(KERN_WARNING "Cannot add context lttng_add_vpid_to_ctx");
07dfc1d0	272	}
b3699d90 MD	273	ret = lttng_add_cpu_id_to_ctx(&lttng_static_ctx);
	274	if (ret) {
	275	printk(KERN_WARNING "Cannot add context lttng_add_cpu_id_to_ctx");
	276	}
79150a49 JD	277	ret = lttng_add_interruptible_to_ctx(&lttng_static_ctx);
	278	if (ret) {
	279	printk(KERN_WARNING "Cannot add context lttng_add_interruptible_to_ctx");
	280	}
	281	ret = lttng_add_need_reschedule_to_ctx(&lttng_static_ctx);
	282	if (ret) {
	283	printk(KERN_WARNING "Cannot add context lttng_add_need_reschedule_to_ctx");
	284	}
79150a49	285	ret = lttng_add_preemptible_to_ctx(&lttng_static_ctx);
26e3ab8f	286	if (ret && ret != -ENOSYS) {
79150a49 JD	287	printk(KERN_WARNING "Cannot add context lttng_add_preemptible_to_ctx");
79150a49 JD	288	}
79150a49	289	ret = lttng_add_migratable_to_ctx(&lttng_static_ctx);
26e3ab8f	290	if (ret && ret != -ENOSYS) {
79150a49 JD	291	printk(KERN_WARNING "Cannot add context lttng_add_migratable_to_ctx");
79150a49 JD	292	}
f127e61e	293	/* TODO: perf counters for filtering */
07dfc1d0 MD	294	return 0;
	295	}
	296
	297	void lttng_context_exit(void)
	298	{
	299	lttng_destroy_context(lttng_static_ctx);
	300	lttng_static_ctx = NULL;
	301	}