[lttng-ust.git] / liblttng-ust / lttng-context.c

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * LTTng UST trace/channel/event context management.
 */

#define _LGPL_SOURCE
#include <lttng/ust-events.h>
#include <lttng/ust-tracer.h>
#include <lttng/ust-context-provider.h>
#include <lttng/urcu/pointer.h>
#include <usterr-signal-safe.h>
#include <helper.h>
#include <stddef.h>
#include <string.h>
#include <assert.h>
#include "tracepoint-internal.h"

#include "context-internal.h"

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

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

	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 1;
	}
	return 0;
}

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;
}

static int lttng_find_context_provider(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 (!strncmp(ctx->fields[i].event_field.name, name,
				strlen(name)))
			return 1;
	}
	return 0;
}

/*
 * 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 = zmalloc(sizeof(struct lttng_ctx));
		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 = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field));
		if (!new_fields)
			return NULL;
		if (ctx->fields)
			memcpy(new_fields, ctx->fields, sizeof(*ctx->fields) * ctx->nr_fields);
		free(ctx->fields);
		ctx->fields = new_fields;
	}
	field = &ctx->fields[ctx->nr_fields];
	ctx->nr_fields++;
	return field;
}

int lttng_context_add_rcu(struct lttng_ctx **ctx_p,
		const struct lttng_ctx_field *f)
{
	struct lttng_ctx *old_ctx = *ctx_p, *new_ctx = NULL;
	struct lttng_ctx_field *new_fields = NULL;
	struct lttng_ctx_field *nf;

	if (old_ctx) {
		new_ctx = zmalloc(sizeof(struct lttng_ctx));
		if (!new_ctx)
			return -ENOMEM;
		*new_ctx = *old_ctx;
		new_fields = zmalloc(new_ctx->allocated_fields
				* sizeof(struct lttng_ctx_field));
		if (!new_fields) {
			free(new_ctx);
			return -ENOMEM;
		}
		memcpy(new_fields, old_ctx->fields,
				sizeof(*old_ctx->fields) * old_ctx->nr_fields);
		new_ctx->fields = new_fields;
	}
	nf = lttng_append_context(&new_ctx);
	if (!nf) {
		free(new_fields);
		free(new_ctx);
		return -ENOMEM;
	}
	*nf = *f;
	lttng_context_update(new_ctx);
	lttng_ust_rcu_assign_pointer(*ctx_p, new_ctx);
	lttng_ust_synchronize_trace();
	if (old_ctx) {
		free(old_ctx->fields);
		free(old_ctx);
	}
	return 0;
}

/*
 * 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.integer.alignment;
			break;
		case atype_array:
		{
			struct lttng_basic_type *btype;

			btype = &type->u.legacy.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_array_nestable:
			case atype_sequence:
			case atype_sequence_nestable:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			break;
		}
		case atype_array_nestable:
		{
			const struct lttng_type *nested_type;

			nested_type = type->u.array_nestable.elem_type;
			switch (nested_type->atype) {
			case atype_integer:
				field_align = nested_type->u.integer.alignment;
				break;
			case atype_string:
				break;

			case atype_array:
			case atype_array_nestable:
			case atype_sequence:
			case atype_sequence_nestable:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			field_align = max_t(size_t, field_align,
					type->u.array_nestable.alignment);
			break;
		}
		case atype_sequence:
		{
			struct lttng_basic_type *btype;

			btype = &type->u.legacy.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_array_nestable:
			case atype_sequence:
			case atype_sequence_nestable:
			default:
				WARN_ON_ONCE(1);
				break;
			}

			btype = &type->u.legacy.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_array_nestable:
			case atype_sequence:
			case atype_sequence_nestable:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			break;
		}
		case atype_sequence_nestable:
		{
			const struct lttng_type *nested_type;

			nested_type = type->u.sequence_nestable.elem_type;
			switch (nested_type->atype) {
			case atype_integer:
				field_align = nested_type->u.integer.alignment;
				break;

			case atype_string:
				break;

			case atype_array:
			case atype_array_nestable:
			case atype_sequence:
			case atype_sequence_nestable:
			default:
				WARN_ON_ONCE(1);
				break;
			}
			field_align = max_t(size_t, field_align,
					type->u.sequence_nestable.alignment);
			break;
		}
		case atype_string:
			break;
		case atype_dynamic:
			break;
		case atype_enum:
		case atype_enum_nestable:
		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--;
	assert(&ctx->fields[ctx->nr_fields] == field);
	assert(field->field_name == NULL);
	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_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]);
		free(ctx->fields[i].field_name);
	}
	free(ctx->fields);
	free(ctx);
}

/*
 * Can be safely performed concurrently with tracing using the struct
 * lttng_ctx. Using RCU update. Needs to match RCU read-side handling of
 * contexts.
 *
 * This does not allow adding, removing, or changing typing of the
 * contexts, since this needs to stay invariant for metadata. However,
 * it allows updating the handlers associated with all contexts matching
 * a provider (by name) while tracing is using it, in a way that ensures
 * a single RCU read-side critical section see either all old, or all
 * new handlers.
 */
int lttng_ust_context_set_provider_rcu(struct lttng_ctx **_ctx,
		const char *name,
		size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
		void (*record)(struct lttng_ctx_field *field,
			struct lttng_ust_lib_ring_buffer_ctx *ctx,
			struct lttng_channel *chan),
		void (*get_value)(struct lttng_ctx_field *field,
			struct lttng_ctx_value *value))
{
	int i, ret;
	struct lttng_ctx *ctx = *_ctx, *new_ctx;
	struct lttng_ctx_field *new_fields;

	if (!ctx || !lttng_find_context_provider(ctx, name))
		return 0;
	/*
	 * We have at least one instance of context for the provider.
	 */
	new_ctx = zmalloc(sizeof(*new_ctx));
	if (!new_ctx)
		return -ENOMEM;
	*new_ctx = *ctx;
	new_fields = zmalloc(sizeof(*new_fields) * ctx->allocated_fields);
	if (!new_fields) {
		ret = -ENOMEM;
		goto field_error;
	}
	memcpy(new_fields, ctx->fields,
		sizeof(*new_fields) * ctx->allocated_fields);
	for (i = 0; i < ctx->nr_fields; i++) {
		if (strncmp(new_fields[i].event_field.name,
				name, strlen(name)) != 0)
			continue;
		new_fields[i].get_size = get_size;
		new_fields[i].record = record;
		new_fields[i].get_value = get_value;
	}
	new_ctx->fields = new_fields;
	lttng_ust_rcu_assign_pointer(*_ctx, new_ctx);
	lttng_ust_synchronize_trace();
	free(ctx->fields);
	free(ctx);
	return 0;

field_error:
	free(new_ctx);
	return ret;
}

int lttng_context_init_all(struct lttng_ctx **ctx)
{
	int ret;

	ret = lttng_add_pthread_id_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_pthread_id_to_ctx");
		goto error;
	}
	ret = lttng_add_vtid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vtid_to_ctx");
		goto error;
	}
	ret = lttng_add_vpid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vpid_to_ctx");
		goto error;
	}
	ret = lttng_add_procname_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_procname_to_ctx");
		goto error;
	}
	ret = lttng_add_cpu_id_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_cpu_id_to_ctx");
		goto error;
	}
	ret = lttng_add_cgroup_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_cgroup_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_ipc_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_ipc_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_mnt_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_mnt_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_net_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_net_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_pid_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_pid_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_time_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_time_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_user_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_user_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_uts_ns_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_uts_ns_to_ctx");
		goto error;
	}
	ret = lttng_add_vuid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vuid_to_ctx");
		goto error;
	}
	ret = lttng_add_veuid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_veuid_to_ctx");
		goto error;
	}
	ret = lttng_add_vsuid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vsuid_to_ctx");
		goto error;
	}
	ret = lttng_add_vgid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vgid_to_ctx");
		goto error;
	}
	ret = lttng_add_vegid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vegid_to_ctx");
		goto error;
	}
	ret = lttng_add_vsgid_to_ctx(ctx);
	if (ret) {
		WARN("Cannot add context lttng_add_vsgid_to_ctx");
		goto error;
	}
	lttng_context_update(*ctx);
	return 0;

error:
	lttng_destroy_context(*ctx);
	return ret;
}
Commit	Line	Data
8020ceb5	1	/*
c0c0989a	2	* SPDX-License-Identifier: LGPL-2.1-only
8020ceb5	3	*
e92f3e28 MD	4	* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
e92f3e28 MD	5	*
c0c0989a	6	* LTTng UST trace/channel/event context management.
8020ceb5 MD	7	*/
8020ceb5 MD	8
3fbec7dc	9	#define _LGPL_SOURCE
4318ae1b MD	10	#include <lttng/ust-events.h>
4318ae1b MD	11	#include <lttng/ust-tracer.h>
53569322	12	#include <lttng/ust-context-provider.h>
10544ee8	13	#include <lttng/urcu/pointer.h>
a0a3bef9	14	#include <usterr-signal-safe.h>
35897f8b	15	#include <helper.h>
b4051ad8	16	#include <stddef.h>
8d8a24c8	17	#include <string.h>
8173ec7c	18	#include <assert.h>
10544ee8	19	#include "tracepoint-internal.h"
8173ec7c	20
51f804ec FD	21	#include "context-internal.h"
51f804ec FD	22
77aa5901 MD	23	/*
	24	* The filter implementation requires that two consecutive "get" for the
	25	* same context performed by the same thread return the same result.
	26	*/
	27
8173ec7c MD	28	int lttng_find_context(struct lttng_ctx ctx, const char name)
	29	{
	30	unsigned int i;
53569322	31	const char *subname;
8173ec7c	32
53569322 MD	33	if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
	34	subname = name + strlen("$ctx.");
	35	} else {
	36	subname = name;
	37	}
8173ec7c MD	38	for (i = 0; i < ctx->nr_fields; i++) {
	39	/* Skip allocated (but non-initialized) contexts */
	40	if (!ctx->fields[i].event_field.name)
	41	continue;
53569322	42	if (!strcmp(ctx->fields[i].event_field.name, subname))
8173ec7c MD	43	return 1;
	44	}
	45	return 0;
	46	}
8020ceb5	47
77aa5901 MD	48	int lttng_get_context_index(struct lttng_ctx ctx, const char name)
	49	{
	50	unsigned int i;
53569322	51	const char *subname;
77aa5901 MD	52
	53	if (!ctx)
	54	return -1;
53569322 MD	55	if (strncmp(name, "$ctx.", strlen("$ctx.")) == 0) {
	56	subname = name + strlen("$ctx.");
	57	} else {
	58	subname = name;
	59	}
77aa5901 MD	60	for (i = 0; i < ctx->nr_fields; i++) {
	61	/* Skip allocated (but non-initialized) contexts */
	62	if (!ctx->fields[i].event_field.name)
	63	continue;
53569322	64	if (!strcmp(ctx->fields[i].event_field.name, subname))
77aa5901 MD	65	return i;
	66	}
	67	return -1;
	68	}
	69
53569322 MD	70	static int lttng_find_context_provider(struct lttng_ctx ctx, const char name)
	71	{
	72	unsigned int i;
	73
	74	for (i = 0; i < ctx->nr_fields; i++) {
	75	/* Skip allocated (but non-initialized) contexts */
	76	if (!ctx->fields[i].event_field.name)
	77	continue;
	78	if (!strncmp(ctx->fields[i].event_field.name, name,
	79	strlen(name)))
	80	return 1;
	81	}
	82	return 0;
	83	}
	84
a0a748b8 MD	85	/*
	86	* Note: as we append context information, the pointer location may change.
	87	*/
8020ceb5 MD	88	struct lttng_ctx_field lttng_append_context(struct lttng_ctx *ctx_p)
	89	{
	90	struct lttng_ctx_field *field;
	91	struct lttng_ctx *ctx;
	92
	93	if (!*ctx_p) {
8d8a24c8	94	*ctx_p = zmalloc(sizeof(struct lttng_ctx));
8020ceb5 MD	95	if (!*ctx_p)
8020ceb5 MD	96	return NULL;
b2cc986a	97	(*ctx_p)->largest_align = 1;
8020ceb5 MD	98	}
	99	ctx = *ctx_p;
	100	if (ctx->nr_fields + 1 > ctx->allocated_fields) {
	101	struct lttng_ctx_field *new_fields;
	102
	103	ctx->allocated_fields = max_t(size_t, 1, 2 * ctx->allocated_fields);
8d8a24c8	104	new_fields = zmalloc(ctx->allocated_fields * sizeof(struct lttng_ctx_field));
8020ceb5 MD	105	if (!new_fields)
	106	return NULL;
	107	if (ctx->fields)
	108	memcpy(new_fields, ctx->fields, sizeof(ctx->fields) ctx->nr_fields);
8d8a24c8	109	free(ctx->fields);
8020ceb5 MD	110	ctx->fields = new_fields;
	111	}
	112	field = &ctx->fields[ctx->nr_fields];
	113	ctx->nr_fields++;
	114	return field;
	115	}
8020ceb5	116
53569322 MD	117	int lttng_context_add_rcu(struct lttng_ctx **ctx_p,
	118	const struct lttng_ctx_field *f)
	119	{
	120	struct lttng_ctx old_ctx = ctx_p, *new_ctx = NULL;
	121	struct lttng_ctx_field *new_fields = NULL;
	122	struct lttng_ctx_field *nf;
	123
	124	if (old_ctx) {
	125	new_ctx = zmalloc(sizeof(struct lttng_ctx));
	126	if (!new_ctx)
	127	return -ENOMEM;
	128	new_ctx = old_ctx;
	129	new_fields = zmalloc(new_ctx->allocated_fields
	130	* sizeof(struct lttng_ctx_field));
	131	if (!new_fields) {
	132	free(new_ctx);
	133	return -ENOMEM;
	134	}
	135	memcpy(new_fields, old_ctx->fields,
	136	sizeof(old_ctx->fields) old_ctx->nr_fields);
	137	new_ctx->fields = new_fields;
	138	}
	139	nf = lttng_append_context(&new_ctx);
	140	if (!nf) {
	141	free(new_fields);
	142	free(new_ctx);
	143	return -ENOMEM;
	144	}
	145	nf = f;
	146	lttng_context_update(new_ctx);
10544ee8 MD	147	lttng_ust_rcu_assign_pointer(*ctx_p, new_ctx);
10544ee8 MD	148	lttng_ust_synchronize_trace();
53569322 MD	149	if (old_ctx) {
	150	free(old_ctx->fields);
	151	free(old_ctx);
	152	}
	153	return 0;
	154	}
	155
b2cc986a MD	156	/*
	157	* lttng_context_update() should be called at least once between context
	158	* modification and trace start.
	159	*/
	160	void lttng_context_update(struct lttng_ctx *ctx)
	161	{
	162	int i;
	163	size_t largest_align = 8; /* in bits */
	164
	165	for (i = 0; i < ctx->nr_fields; i++) {
	166	struct lttng_type *type;
	167	size_t field_align = 8;
	168
	169	type = &ctx->fields[i].event_field.type;
	170	switch (type->atype) {
	171	case atype_integer:
218deb69	172	field_align = type->u.integer.alignment;
b2cc986a MD	173	break;
	174	case atype_array:
	175	{
	176	struct lttng_basic_type *btype;
	177
218deb69	178	btype = &type->u.legacy.array.elem_type;
b2cc986a MD	179	switch (btype->atype) {
	180	case atype_integer:
	181	field_align = btype->u.basic.integer.alignment;
	182	break;
	183	case atype_string:
	184	break;
	185
	186	case atype_array:
218deb69	187	case atype_array_nestable:
b2cc986a	188	case atype_sequence:
218deb69	189	case atype_sequence_nestable:
b2cc986a MD	190	default:
	191	WARN_ON_ONCE(1);
	192	break;
	193	}
	194	break;
	195	}
218deb69 MD	196	case atype_array_nestable:
	197	{
	198	const struct lttng_type *nested_type;
	199
	200	nested_type = type->u.array_nestable.elem_type;
	201	switch (nested_type->atype) {
	202	case atype_integer:
	203	field_align = nested_type->u.integer.alignment;
	204	break;
	205	case atype_string:
	206	break;
	207
	208	case atype_array:
	209	case atype_array_nestable:
	210	case atype_sequence:
	211	case atype_sequence_nestable:
	212	default:
	213	WARN_ON_ONCE(1);
	214	break;
	215	}
	216	field_align = max_t(size_t, field_align,
	217	type->u.array_nestable.alignment);
	218	break;
	219	}
b2cc986a MD	220	case atype_sequence:
	221	{
	222	struct lttng_basic_type *btype;
	223
218deb69	224	btype = &type->u.legacy.sequence.length_type;
b2cc986a MD	225	switch (btype->atype) {
	226	case atype_integer:
	227	field_align = btype->u.basic.integer.alignment;
	228	break;
	229
	230	case atype_string:
	231	case atype_array:
218deb69	232	case atype_array_nestable:
b2cc986a	233	case atype_sequence:
218deb69	234	case atype_sequence_nestable:
b2cc986a MD	235	default:
	236	WARN_ON_ONCE(1);
	237	break;
	238	}
	239
218deb69	240	btype = &type->u.legacy.sequence.elem_type;
b2cc986a MD	241	switch (btype->atype) {
	242	case atype_integer:
	243	field_align = max_t(size_t,
	244	field_align,
	245	btype->u.basic.integer.alignment);
	246	break;
	247
	248	case atype_string:
	249	break;
	250
	251	case atype_array:
218deb69 MD	252	case atype_array_nestable:
	253	case atype_sequence:
	254	case atype_sequence_nestable:
	255	default:
	256	WARN_ON_ONCE(1);
	257	break;
	258	}
	259	break;
	260	}
	261	case atype_sequence_nestable:
	262	{
	263	const struct lttng_type *nested_type;
	264
	265	nested_type = type->u.sequence_nestable.elem_type;
	266	switch (nested_type->atype) {
	267	case atype_integer:
	268	field_align = nested_type->u.integer.alignment;
	269	break;
	270
	271	case atype_string:
	272	break;
	273
	274	case atype_array:
	275	case atype_array_nestable:
b2cc986a	276	case atype_sequence:
218deb69	277	case atype_sequence_nestable:
b2cc986a MD	278	default:
	279	WARN_ON_ONCE(1);
	280	break;
	281	}
218deb69 MD	282	field_align = max_t(size_t, field_align,
218deb69 MD	283	type->u.sequence_nestable.alignment);
b2cc986a MD	284	break;
	285	}
	286	case atype_string:
	287	break;
53569322 MD	288	case atype_dynamic:
53569322 MD	289	break;
b2cc986a	290	case atype_enum:
218deb69	291	case atype_enum_nestable:
b2cc986a MD	292	default:
	293	WARN_ON_ONCE(1);
	294	break;
	295	}
	296	largest_align = max_t(size_t, largest_align, field_align);
	297	}
	298	ctx->largest_align = largest_align >> 3; /* bits to bytes */
	299	}
	300
b13d13b1 MD	301	/*
	302	* Remove last context field.
	303	*/
8020ceb5 MD	304	void lttng_remove_context_field(struct lttng_ctx **ctx_p,
	305	struct lttng_ctx_field *field)
	306	{
	307	struct lttng_ctx *ctx;
	308
	309	ctx = *ctx_p;
	310	ctx->nr_fields--;
8173ec7c	311	assert(&ctx->fields[ctx->nr_fields] == field);
53569322	312	assert(field->field_name == NULL);
8020ceb5 MD	313	memset(&ctx->fields[ctx->nr_fields], 0, sizeof(struct lttng_ctx_field));
8020ceb5 MD	314	}
8020ceb5 MD	315
	316	void lttng_destroy_context(struct lttng_ctx *ctx)
	317	{
	318	int i;
	319
	320	if (!ctx)
	321	return;
	322	for (i = 0; i < ctx->nr_fields; i++) {
	323	if (ctx->fields[i].destroy)
	324	ctx->fields[i].destroy(&ctx->fields[i]);
53569322	325	free(ctx->fields[i].field_name);
8020ceb5	326	}
8d8a24c8 MD	327	free(ctx->fields);
8d8a24c8 MD	328	free(ctx);
8020ceb5	329	}
a0a3bef9	330
53569322 MD	331	/*
	332	* Can be safely performed concurrently with tracing using the struct
	333	* lttng_ctx. Using RCU update. Needs to match RCU read-side handling of
	334	* contexts.
	335	*
	336	* This does not allow adding, removing, or changing typing of the
	337	* contexts, since this needs to stay invariant for metadata. However,
	338	* it allows updating the handlers associated with all contexts matching
	339	* a provider (by name) while tracing is using it, in a way that ensures
	340	* a single RCU read-side critical section see either all old, or all
	341	* new handlers.
	342	*/
	343	int lttng_ust_context_set_provider_rcu(struct lttng_ctx **_ctx,
	344	const char *name,
	345	size_t (get_size)(struct lttng_ctx_field field, size_t offset),
	346	void (record)(struct lttng_ctx_field field,
	347	struct lttng_ust_lib_ring_buffer_ctx *ctx,
	348	struct lttng_channel *chan),
	349	void (get_value)(struct lttng_ctx_field field,
	350	struct lttng_ctx_value *value))
	351	{
	352	int i, ret;
	353	struct lttng_ctx ctx = _ctx, *new_ctx;
	354	struct lttng_ctx_field *new_fields;
	355
	356	if (!ctx \|\| !lttng_find_context_provider(ctx, name))
	357	return 0;
	358	/*
	359	* We have at least one instance of context for the provider.
	360	*/
	361	new_ctx = zmalloc(sizeof(*new_ctx));
	362	if (!new_ctx)
	363	return -ENOMEM;
	364	new_ctx = ctx;
	365	new_fields = zmalloc(sizeof(new_fields) ctx->allocated_fields);
	366	if (!new_fields) {
	367	ret = -ENOMEM;
	368	goto field_error;
	369	}
	370	memcpy(new_fields, ctx->fields,
	371	sizeof(new_fields) ctx->allocated_fields);
	372	for (i = 0; i < ctx->nr_fields; i++) {
	373	if (strncmp(new_fields[i].event_field.name,
	374	name, strlen(name)) != 0)
	375	continue;
	376	new_fields[i].get_size = get_size;
	377	new_fields[i].record = record;
	378	new_fields[i].get_value = get_value;
	379	}
	380	new_ctx->fields = new_fields;
10544ee8 MD	381	lttng_ust_rcu_assign_pointer(*_ctx, new_ctx);
10544ee8 MD	382	lttng_ust_synchronize_trace();
53569322 MD	383	free(ctx->fields);
	384	free(ctx);
	385	return 0;
	386
	387	field_error:
	388	free(new_ctx);
	389	return ret;
	390	}
	391
51f804ec	392	int lttng_context_init_all(struct lttng_ctx **ctx)
a0a3bef9 MD	393	{
	394	int ret;
	395
53569322	396	ret = lttng_add_pthread_id_to_ctx(ctx);
a0a3bef9 MD	397	if (ret) {
a0a3bef9 MD	398	WARN("Cannot add context lttng_add_pthread_id_to_ctx");
53569322	399	goto error;
a0a3bef9	400	}
53569322	401	ret = lttng_add_vtid_to_ctx(ctx);
a0a3bef9 MD	402	if (ret) {
a0a3bef9 MD	403	WARN("Cannot add context lttng_add_vtid_to_ctx");
53569322	404	goto error;
a0a3bef9	405	}
53569322	406	ret = lttng_add_vpid_to_ctx(ctx);
a0a3bef9 MD	407	if (ret) {
a0a3bef9 MD	408	WARN("Cannot add context lttng_add_vpid_to_ctx");
53569322	409	goto error;
a0a3bef9	410	}
53569322	411	ret = lttng_add_procname_to_ctx(ctx);
a0a3bef9 MD	412	if (ret) {
a0a3bef9 MD	413	WARN("Cannot add context lttng_add_procname_to_ctx");
53569322	414	goto error;
a0a3bef9	415	}
53569322	416	ret = lttng_add_cpu_id_to_ctx(ctx);
c7ea8487 MD	417	if (ret) {
c7ea8487 MD	418	WARN("Cannot add context lttng_add_cpu_id_to_ctx");
53569322	419	goto error;
c7ea8487	420	}
735bef47 MJ	421	ret = lttng_add_cgroup_ns_to_ctx(ctx);
	422	if (ret) {
	423	WARN("Cannot add context lttng_add_cgroup_ns_to_ctx");
	424	goto error;
	425	}
	426	ret = lttng_add_ipc_ns_to_ctx(ctx);
	427	if (ret) {
	428	WARN("Cannot add context lttng_add_ipc_ns_to_ctx");
	429	goto error;
	430	}
	431	ret = lttng_add_mnt_ns_to_ctx(ctx);
	432	if (ret) {
	433	WARN("Cannot add context lttng_add_mnt_ns_to_ctx");
	434	goto error;
	435	}
	436	ret = lttng_add_net_ns_to_ctx(ctx);
	437	if (ret) {
	438	WARN("Cannot add context lttng_add_net_ns_to_ctx");
	439	goto error;
	440	}
	441	ret = lttng_add_pid_ns_to_ctx(ctx);
	442	if (ret) {
	443	WARN("Cannot add context lttng_add_pid_ns_to_ctx");
	444	goto error;
	445	}
cefef7a7 MJ	446	ret = lttng_add_time_ns_to_ctx(ctx);
	447	if (ret) {
	448	WARN("Cannot add context lttng_add_time_ns_to_ctx");
	449	goto error;
	450	}
735bef47 MJ	451	ret = lttng_add_user_ns_to_ctx(ctx);
	452	if (ret) {
	453	WARN("Cannot add context lttng_add_user_ns_to_ctx");
	454	goto error;
	455	}
	456	ret = lttng_add_uts_ns_to_ctx(ctx);
	457	if (ret) {
	458	WARN("Cannot add context lttng_add_uts_ns_to_ctx");
	459	goto error;
	460	}
fca2f191 MJ	461	ret = lttng_add_vuid_to_ctx(ctx);
	462	if (ret) {
	463	WARN("Cannot add context lttng_add_vuid_to_ctx");
	464	goto error;
	465	}
	466	ret = lttng_add_veuid_to_ctx(ctx);
	467	if (ret) {
	468	WARN("Cannot add context lttng_add_veuid_to_ctx");
	469	goto error;
	470	}
	471	ret = lttng_add_vsuid_to_ctx(ctx);
	472	if (ret) {
	473	WARN("Cannot add context lttng_add_vsuid_to_ctx");
	474	goto error;
	475	}
	476	ret = lttng_add_vgid_to_ctx(ctx);
	477	if (ret) {
	478	WARN("Cannot add context lttng_add_vgid_to_ctx");
	479	goto error;
	480	}
	481	ret = lttng_add_vegid_to_ctx(ctx);
	482	if (ret) {
	483	WARN("Cannot add context lttng_add_vegid_to_ctx");
	484	goto error;
	485	}
	486	ret = lttng_add_vsgid_to_ctx(ctx);
	487	if (ret) {
	488	WARN("Cannot add context lttng_add_vsgid_to_ctx");
	489	goto error;
	490	}
53569322 MD	491	lttng_context_update(*ctx);
53569322 MD	492	return 0;
a0a3bef9	493
53569322 MD	494	error:
	495	lttng_destroy_context(*ctx);
	496	return ret;
a0a3bef9	497	}