[lttng-ust.git] / src / lib / lttng-ust / event-notifier-notification.c

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
 */

#define _LGPL_SOURCE

#include <assert.h>
#include <errno.h>
#include <limits.h>

#include <lttng/ust-endian.h>
#include "common/logging.h"
#include <urcu/rculist.h>

#include "lttng-tracer-core.h"
#include "lib/lttng-ust/events.h"
#include "common/msgpack/msgpack.h"
#include "lttng-bytecode.h"
#include "common/patient.h"

/*
 * We want this write to be atomic AND non-blocking, meaning that we
 * want to write either everything OR nothing.
 * According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be
 * atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size
 * of the notification struct we are sending alongside the capture buffer.
 */
#define CAPTURE_BUFFER_SIZE \
	(PIPE_BUF - sizeof(struct lttng_ust_abi_event_notifier_notification) - 1)

struct lttng_event_notifier_notification {
	int notification_fd;
	uint64_t event_notifier_token;
	uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
	struct lttng_msgpack_writer writer;
	bool has_captures;
};

static
int capture_enum(struct lttng_msgpack_writer *writer,
		struct lttng_interpreter_output *output)
{
	int ret;

	ret = lttng_msgpack_begin_map(writer, 2);
	if (ret) {
		goto end;
	}
	ret = lttng_msgpack_write_str(writer, "type");
	if (ret) {
		goto end;
	}
	ret = lttng_msgpack_write_str(writer, "enum");
	if (ret) {
		goto end;
	}
	ret = lttng_msgpack_write_str(writer, "value");
	if (ret) {
		goto end;
	}

	switch (output->type) {
	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
		ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
		if (ret) {
			goto end;
		}
		break;
	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
		ret = lttng_msgpack_write_signed_integer(writer, output->u.u);
		if (ret) {
			goto end;
		}
		break;
	default:
		CRIT("Unknown enum output type\n");
		ret = -1;
		goto end;
	}

	ret = lttng_msgpack_end_map(writer);
end:
	return ret;
}

static
int64_t capture_sequence_element_signed(uint8_t *ptr,
		const struct lttng_ust_type_integer *integer_type)
{
	int64_t value;
	unsigned int size = integer_type->size;
	bool byte_order_reversed = integer_type->reverse_byte_order;

	switch (size) {
	case 8:
		value = *ptr;
		break;
	case 16:
	{
		int16_t tmp;
		tmp = *(int16_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_16(tmp);

		value = tmp;
		break;
	}
	case 32:
	{
		int32_t tmp;
		tmp = *(int32_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_32(tmp);

		value = tmp;
		break;
	}
	case 64:
	{
		int64_t tmp;
		tmp = *(int64_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_64(tmp);

		value = tmp;
		break;
	}
	default:
		CRIT("Unknown sequence element size\n");
		value = 0;
	}

	return value;
}

static
uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
		const struct lttng_ust_type_integer *integer_type)
{
	uint64_t value;
	unsigned int size = integer_type->size;
	bool byte_order_reversed = integer_type->reverse_byte_order;

	switch (size) {
	case 8:
		value = *ptr;
		break;
	case 16:
	{
		uint16_t tmp;
		tmp = *(uint16_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_16(tmp);

		value = tmp;
		break;
	}
	case 32:
	{
		uint32_t tmp;
		tmp = *(uint32_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_32(tmp);

		value = tmp;
		break;
	}
	case 64:
	{
		uint64_t tmp;
		tmp = *(uint64_t *) ptr;
		if (byte_order_reversed)
			tmp = lttng_ust_bswap_64(tmp);

		value = tmp;
		break;
	}
	default:
		CRIT("Unknown sequence element size\n");
		value = 0;
	}

	return value;
}

static
int capture_sequence(struct lttng_msgpack_writer *writer,
		struct lttng_interpreter_output *output)
{
	const struct lttng_ust_type_integer *integer_type;
	const struct lttng_ust_type_common *nested_type;
	uint8_t *ptr;
	bool signedness;
	int i, ret;

	ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
	if (ret) {
		goto end;
	}
	ptr = (uint8_t *) output->u.sequence.ptr;
	nested_type = output->u.sequence.nested_type;
	switch (nested_type->type) {
	case lttng_ust_type_integer:
		integer_type = lttng_ust_get_type_integer(nested_type);
		break;
	case lttng_ust_type_enum:
		/* Treat enumeration as an integer. */
		integer_type = lttng_ust_get_type_integer(lttng_ust_get_type_enum(nested_type)->container_type);
		break;
	default:
		CRIT("Capture of array of non-integer are not supported\n");
		ret = -1;
		goto end;
	}
	signedness = integer_type->signedness;
	for (i = 0; i < output->u.sequence.nr_elem; i++) {
		if (signedness) {
			ret = lttng_msgpack_write_signed_integer(writer,
				capture_sequence_element_signed(ptr, integer_type));
		} else {
			ret = lttng_msgpack_write_unsigned_integer(writer,
				capture_sequence_element_unsigned(ptr, integer_type));
		}
		if (ret) {
			goto end;
		}

		/*
		 * We assume that alignment is smaller or equal to the size.
		 * This currently holds true but if it changes in the future,
		 * we will want to change the pointer arithmetic below to
		 * take into account that the next element might be further
		 * away.
		 */
		assert(integer_type->alignment <= integer_type->size);

		/* Size is in number of bits. */
		ptr += (integer_type->size / CHAR_BIT) ;
	}

	ret = lttng_msgpack_end_array(writer);
end:
	return ret;
}

static
int notification_init(struct lttng_event_notifier_notification *notif,
		const struct lttng_ust_event_notifier *event_notifier)
{
	struct lttng_msgpack_writer *writer = &notif->writer;
	int ret = 0;

	notif->event_notifier_token = event_notifier->priv->parent.user_token;
	notif->notification_fd = event_notifier->priv->group->notification_fd;
	notif->has_captures = false;

	if (event_notifier->priv->num_captures > 0) {
		lttng_msgpack_writer_init(writer, notif->capture_buf,
				CAPTURE_BUFFER_SIZE);

		ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
		if (ret) {
			goto end;
		}
		notif->has_captures = true;
	}
end:
	return ret;
}

static
int notification_append_capture(
		struct lttng_event_notifier_notification *notif,
		struct lttng_interpreter_output *output)
{
	struct lttng_msgpack_writer *writer = &notif->writer;
	int ret;

	switch (output->type) {
	case LTTNG_INTERPRETER_TYPE_S64:
		ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
		break;
	case LTTNG_INTERPRETER_TYPE_U64:
		ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u);
		break;
	case LTTNG_INTERPRETER_TYPE_DOUBLE:
		ret = lttng_msgpack_write_double(writer, output->u.d);
		break;
	case LTTNG_INTERPRETER_TYPE_STRING:
		ret = lttng_msgpack_write_str(writer, output->u.str.str);
		break;
	case LTTNG_INTERPRETER_TYPE_SEQUENCE:
		ret = capture_sequence(writer, output);
		break;
	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
		ret = capture_enum(writer, output);
		break;
	default:
		CRIT("Unknown capture output type\n");
		ret = -1;
	}
	return ret;
}

static
int notification_append_empty_capture(
		struct lttng_event_notifier_notification *notif)
{
	return lttng_msgpack_write_nil(&notif->writer);
}

static void record_error(const struct lttng_ust_event_notifier *event_notifier)
{
	struct lttng_event_notifier_group *event_notifier_group =
			event_notifier->priv->group;
	struct lttng_counter *error_counter;
	size_t dimension_index[1];
	int ret;

	error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter);
	/*
	 * load-acquire paired with store-release orders creation of the
	 * error counter and setting error_counter_len before the
	 * error_counter is used.
	 * Currently a full memory barrier is used, which could be
	 * turned into acquire-release barriers.
	 */
	cmm_smp_mb();
	/* This group may not have an error counter attached to it. */
	if (!error_counter)
		return;

	dimension_index[0] = event_notifier->priv->error_counter_index;
	ret = event_notifier_group->error_counter->ops->counter_add(
			error_counter->counter, dimension_index, 1);
	if (ret)
		WARN_ON_ONCE(1);
}

static
void notification_send(struct lttng_event_notifier_notification *notif,
		const struct lttng_ust_event_notifier *event_notifier)
{
	ssize_t ret;
	size_t content_len;
	int iovec_count = 1;
	struct lttng_ust_abi_event_notifier_notification ust_notif = {0};
	struct iovec iov[2];

	assert(notif);

	ust_notif.token = event_notifier->priv->parent.user_token;

	/*
	 * Prepare sending the notification from multiple buffers using an
	 * array of `struct iovec`. The first buffer of the vector is
	 * notification structure itself and is always present.
	 */
	iov[0].iov_base = &ust_notif;
	iov[0].iov_len = sizeof(ust_notif);

	if (notif->has_captures) {
		/*
		 * If captures were requested, the second buffer of the array
		 * is the capture buffer.
		 */
		assert(notif->writer.buffer);
		content_len = notif->writer.write_pos - notif->writer.buffer;

		assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE);

		iov[1].iov_base = notif->capture_buf;
		iov[1].iov_len = content_len;

		iovec_count++;
	} else {
		content_len = 0;
	}

	/*
	 * Update the capture buffer size so that receiver of the buffer will
	 * know how much to expect.
	 */
	ust_notif.capture_buf_size = content_len;

	/* Send all the buffers. */
	ret = ust_patient_writev(notif->notification_fd, iov, iovec_count);
	if (ret == -1) {
		if (errno == EAGAIN) {
			record_error(event_notifier);
			DBG("Cannot send event_notifier notification without blocking: %s",
				strerror(errno));
		} else {
			DBG("Error to sending event notifier notification: %s",
				strerror(errno));
			abort();
		}
	}
}

void lttng_event_notifier_notification_send(
		const struct lttng_ust_event_notifier *event_notifier,
		const char *stack_data,
		struct lttng_ust_probe_ctx *probe_ctx,
		struct lttng_ust_notification_ctx *notif_ctx)
{
	/*
	 * This function is called from the probe, we must do dynamic
	 * allocation in this context.
	 */
	struct lttng_event_notifier_notification notif = {0};

	if (notification_init(&notif, event_notifier)) {
		record_error(event_notifier);
		goto end;
	}

	if (caa_unlikely(notif_ctx->eval_capture)) {
		struct lttng_ust_bytecode_runtime *capture_bc_runtime;

		/*
		 * Iterate over all the capture bytecodes. If the interpreter
		 * functions returns successfully, append the value of the
		 * `output` parameter to the capture buffer. If the interpreter
		 * fails, append an empty capture to the buffer.
		 */
		cds_list_for_each_entry_rcu(capture_bc_runtime,
				&event_notifier->priv->capture_bytecode_runtime_head, node) {
			struct lttng_interpreter_output output;
			uint8_t *save_pos;
			int ret;

			lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
			if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
					stack_data, probe_ctx, &output) == LTTNG_UST_BYTECODE_INTERPRETER_OK)
				ret = notification_append_capture(&notif, &output);
			else
				ret = notification_append_empty_capture(&notif);
			if (ret) {
				/*
				 * On append capture error, skip the field
				 * capture by restoring the msgpack writer
				 * position.
				 */
				lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
			}
		}
	}

	/*
	 * Send the notification (including the capture buffer) to the
	 * sessiond.
	 */
	notification_send(&notif, event_notifier);
end:
	return;
}
Commit	Line	Data
d8d2416d	1	/*
c0c0989a	2	* SPDX-License-Identifier: LGPL-2.1-only
d8d2416d FD	3	*
d8d2416d FD	4	* Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
d8d2416d FD	5	*/
	6
	7	#define _LGPL_SOURCE
	8
b9f82a28	9	#include <assert.h>
d8d2416d	10	#include <errno.h>
9af5d97a MJ	11	#include <limits.h>
9af5d97a MJ	12
f03092d7	13	#include <lttng/ust-endian.h>
9d315d6d	14	#include "common/logging.h"
a2e4d05e	15	#include <urcu/rculist.h>
d8d2416d	16
4b4a1337	17	#include "lttng-tracer-core.h"
36c52fff	18	#include "lib/lttng-ust/events.h"
c3ba99c2	19	#include "common/msgpack/msgpack.h"
b9f82a28	20	#include "lttng-bytecode.h"
9d315d6d	21	#include "common/patient.h"
d8d2416d	22
d37ecb3f FD	23	/*
	24	* We want this write to be atomic AND non-blocking, meaning that we
	25	* want to write either everything OR nothing.
	26	* According to `pipe(7)`, writes that are less than `PIPE_BUF` bytes must be
	27	* atomic, so we bound the capture buffer size to the `PIPE_BUF` minus the size
	28	* of the notification struct we are sending alongside the capture buffer.
	29	*/
	30	#define CAPTURE_BUFFER_SIZE \
fd17d7ce	31	(PIPE_BUF - sizeof(struct lttng_ust_abi_event_notifier_notification) - 1)
d37ecb3f FD	32
	33	struct lttng_event_notifier_notification {
	34	int notification_fd;
	35	uint64_t event_notifier_token;
	36	uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
	37	struct lttng_msgpack_writer writer;
	38	bool has_captures;
	39	};
	40
b9f82a28	41	static
c651e872	42	int capture_enum(struct lttng_msgpack_writer *writer,
b9f82a28 FD	43	struct lttng_interpreter_output *output)
b9f82a28 FD	44	{
c651e872	45	int ret;
b9f82a28	46
c651e872 MD	47	ret = lttng_msgpack_begin_map(writer, 2);
	48	if (ret) {
	49	goto end;
	50	}
	51	ret = lttng_msgpack_write_str(writer, "type");
	52	if (ret) {
	53	goto end;
	54	}
	55	ret = lttng_msgpack_write_str(writer, "enum");
	56	if (ret) {
	57	goto end;
	58	}
	59	ret = lttng_msgpack_write_str(writer, "value");
	60	if (ret) {
	61	goto end;
	62	}
b9f82a28 FD	63
	64	switch (output->type) {
	65	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
c651e872 MD	66	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
	67	if (ret) {
	68	goto end;
	69	}
b9f82a28 FD	70	break;
b9f82a28 FD	71	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
c651e872 MD	72	ret = lttng_msgpack_write_signed_integer(writer, output->u.u);
	73	if (ret) {
	74	goto end;
	75	}
b9f82a28 FD	76	break;
b9f82a28 FD	77	default:
c651e872 MD	78	CRIT("Unknown enum output type\n");
	79	ret = -1;
	80	goto end;
b9f82a28 FD	81	}
b9f82a28 FD	82
c651e872 MD	83	ret = lttng_msgpack_end_map(writer);
	84	end:
	85	return ret;
b9f82a28 FD	86	}
	87
	88	static
	89	int64_t capture_sequence_element_signed(uint8_t *ptr,
4e48b5d2	90	const struct lttng_ust_type_integer *integer_type)
b9f82a28 FD	91	{
b9f82a28 FD	92	int64_t value;
a084756d MD	93	unsigned int size = integer_type->size;
a084756d MD	94	bool byte_order_reversed = integer_type->reverse_byte_order;
b9f82a28 FD	95
	96	switch (size) {
	97	case 8:
	98	value = *ptr;
	99	break;
	100	case 16:
	101	{
	102	int16_t tmp;
	103	tmp = (int16_t ) ptr;
	104	if (byte_order_reversed)
baa8acf3	105	tmp = lttng_ust_bswap_16(tmp);
b9f82a28 FD	106
	107	value = tmp;
	108	break;
	109	}
	110	case 32:
	111	{
	112	int32_t tmp;
	113	tmp = (int32_t ) ptr;
	114	if (byte_order_reversed)
baa8acf3	115	tmp = lttng_ust_bswap_32(tmp);
b9f82a28 FD	116
	117	value = tmp;
	118	break;
	119	}
	120	case 64:
	121	{
	122	int64_t tmp;
	123	tmp = (int64_t ) ptr;
	124	if (byte_order_reversed)
baa8acf3	125	tmp = lttng_ust_bswap_64(tmp);
b9f82a28 FD	126
	127	value = tmp;
	128	break;
	129	}
	130	default:
c651e872 MD	131	CRIT("Unknown sequence element size\n");
c651e872 MD	132	value = 0;
b9f82a28 FD	133	}
	134
	135	return value;
	136	}
	137
	138	static
	139	uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
4e48b5d2	140	const struct lttng_ust_type_integer *integer_type)
b9f82a28 FD	141	{
b9f82a28 FD	142	uint64_t value;
a084756d MD	143	unsigned int size = integer_type->size;
a084756d MD	144	bool byte_order_reversed = integer_type->reverse_byte_order;
b9f82a28 FD	145
	146	switch (size) {
	147	case 8:
	148	value = *ptr;
	149	break;
	150	case 16:
	151	{
	152	uint16_t tmp;
	153	tmp = (uint16_t ) ptr;
	154	if (byte_order_reversed)
baa8acf3	155	tmp = lttng_ust_bswap_16(tmp);
b9f82a28 FD	156
	157	value = tmp;
	158	break;
	159	}
	160	case 32:
	161	{
	162	uint32_t tmp;
	163	tmp = (uint32_t ) ptr;
	164	if (byte_order_reversed)
baa8acf3	165	tmp = lttng_ust_bswap_32(tmp);
b9f82a28 FD	166
	167	value = tmp;
	168	break;
	169	}
	170	case 64:
	171	{
	172	uint64_t tmp;
	173	tmp = (uint64_t ) ptr;
	174	if (byte_order_reversed)
baa8acf3	175	tmp = lttng_ust_bswap_64(tmp);
b9f82a28 FD	176
	177	value = tmp;
	178	break;
	179	}
	180	default:
c651e872 MD	181	CRIT("Unknown sequence element size\n");
c651e872 MD	182	value = 0;
b9f82a28 FD	183	}
	184
	185	return value;
	186	}
	187
b9f82a28	188	static
c651e872	189	int capture_sequence(struct lttng_msgpack_writer *writer,
b9f82a28 FD	190	struct lttng_interpreter_output *output)
b9f82a28 FD	191	{
4e48b5d2 MD	192	const struct lttng_ust_type_integer *integer_type;
4e48b5d2 MD	193	const struct lttng_ust_type_common *nested_type;
b9f82a28 FD	194	uint8_t *ptr;
b9f82a28 FD	195	bool signedness;
c651e872	196	int i, ret;
b9f82a28	197
c651e872 MD	198	ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
	199	if (ret) {
	200	goto end;
	201	}
b9f82a28 FD	202	ptr = (uint8_t *) output->u.sequence.ptr;
b9f82a28 FD	203	nested_type = output->u.sequence.nested_type;
a084756d MD	204	switch (nested_type->type) {
	205	case lttng_ust_type_integer:
	206	integer_type = lttng_ust_get_type_integer(nested_type);
b9f82a28	207	break;
a084756d	208	case lttng_ust_type_enum:
b9f82a28	209	/* Treat enumeration as an integer. */
a084756d	210	integer_type = lttng_ust_get_type_integer(lttng_ust_get_type_enum(nested_type)->container_type);
b9f82a28 FD	211	break;
b9f82a28 FD	212	default:
c651e872 MD	213	CRIT("Capture of array of non-integer are not supported\n");
	214	ret = -1;
	215	goto end;
b9f82a28 FD	216	}
	217	signedness = integer_type->signedness;
	218	for (i = 0; i < output->u.sequence.nr_elem; i++) {
	219	if (signedness) {
c651e872	220	ret = lttng_msgpack_write_signed_integer(writer,
b9f82a28 FD	221	capture_sequence_element_signed(ptr, integer_type));
b9f82a28 FD	222	} else {
c651e872	223	ret = lttng_msgpack_write_unsigned_integer(writer,
b9f82a28 FD	224	capture_sequence_element_unsigned(ptr, integer_type));
b9f82a28 FD	225	}
c651e872 MD	226	if (ret) {
	227	goto end;
	228	}
b9f82a28 FD	229
	230	/*
	231	* We assume that alignment is smaller or equal to the size.
	232	* This currently holds true but if it changes in the future,
2fbda51c	233	* we will want to change the pointer arithmetic below to
b9f82a28 FD	234	* take into account that the next element might be further
	235	* away.
	236	*/
	237	assert(integer_type->alignment <= integer_type->size);
	238
	239	/* Size is in number of bits. */
	240	ptr += (integer_type->size / CHAR_BIT) ;
	241	}
	242
c651e872 MD	243	ret = lttng_msgpack_end_array(writer);
	244	end:
	245	return ret;
b9f82a28 FD	246	}
b9f82a28 FD	247
d37ecb3f	248	static
c651e872	249	int notification_init(struct lttng_event_notifier_notification *notif,
cda77256	250	const struct lttng_ust_event_notifier *event_notifier)
d8d2416d	251	{
d37ecb3f	252	struct lttng_msgpack_writer *writer = &notif->writer;
c651e872	253	int ret = 0;
d37ecb3f	254
115db533 MD	255	notif->event_notifier_token = event_notifier->priv->parent.user_token;
115db533 MD	256	notif->notification_fd = event_notifier->priv->group->notification_fd;
d37ecb3f FD	257	notif->has_captures = false;
d37ecb3f FD	258
115db533	259	if (event_notifier->priv->num_captures > 0) {
d37ecb3f FD	260	lttng_msgpack_writer_init(writer, notif->capture_buf,
	261	CAPTURE_BUFFER_SIZE);
	262
c651e872 MD	263	ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
	264	if (ret) {
	265	goto end;
	266	}
d37ecb3f FD	267	notif->has_captures = true;
d37ecb3f FD	268	}
c651e872 MD	269	end:
c651e872 MD	270	return ret;
d37ecb3f FD	271	}
	272
	273	static
c651e872	274	int notification_append_capture(
d37ecb3f FD	275	struct lttng_event_notifier_notification *notif,
	276	struct lttng_interpreter_output *output)
	277	{
	278	struct lttng_msgpack_writer *writer = &notif->writer;
c651e872	279	int ret;
d37ecb3f FD	280
	281	switch (output->type) {
	282	case LTTNG_INTERPRETER_TYPE_S64:
c651e872	283	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
d37ecb3f FD	284	break;
d37ecb3f FD	285	case LTTNG_INTERPRETER_TYPE_U64:
c651e872	286	ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u);
d37ecb3f FD	287	break;
d37ecb3f FD	288	case LTTNG_INTERPRETER_TYPE_DOUBLE:
c651e872	289	ret = lttng_msgpack_write_double(writer, output->u.d);
d37ecb3f FD	290	break;
d37ecb3f FD	291	case LTTNG_INTERPRETER_TYPE_STRING:
c651e872	292	ret = lttng_msgpack_write_str(writer, output->u.str.str);
d37ecb3f FD	293	break;
d37ecb3f FD	294	case LTTNG_INTERPRETER_TYPE_SEQUENCE:
c651e872	295	ret = capture_sequence(writer, output);
d37ecb3f FD	296	break;
	297	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	298	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
c651e872	299	ret = capture_enum(writer, output);
d37ecb3f FD	300	break;
d37ecb3f FD	301	default:
c651e872 MD	302	CRIT("Unknown capture output type\n");
c651e872 MD	303	ret = -1;
d37ecb3f	304	}
c651e872	305	return ret;
d37ecb3f FD	306	}
	307
	308	static
c651e872	309	int notification_append_empty_capture(
d37ecb3f FD	310	struct lttng_event_notifier_notification *notif)
d37ecb3f FD	311	{
c651e872	312	return lttng_msgpack_write_nil(&notif->writer);
d37ecb3f FD	313	}
d37ecb3f FD	314
cda77256	315	static void record_error(const struct lttng_ust_event_notifier *event_notifier)
6566528b FD	316	{
6566528b FD	317	struct lttng_event_notifier_group *event_notifier_group =
115db533	318	event_notifier->priv->group;
33f43caa	319	struct lttng_counter *error_counter;
6566528b FD	320	size_t dimension_index[1];
	321	int ret;
	322
33f43caa MD	323	error_counter = CMM_LOAD_SHARED(event_notifier_group->error_counter);
	324	/*
	325	* load-acquire paired with store-release orders creation of the
	326	* error counter and setting error_counter_len before the
	327	* error_counter is used.
	328	* Currently a full memory barrier is used, which could be
	329	* turned into acquire-release barriers.
	330	*/
	331	cmm_smp_mb();
c30ad764	332	/* This group may not have an error counter attached to it. */
33f43caa	333	if (!error_counter)
c30ad764 MD	334	return;
c30ad764 MD	335
115db533	336	dimension_index[0] = event_notifier->priv->error_counter_index;
6566528b	337	ret = event_notifier_group->error_counter->ops->counter_add(
33f43caa	338	error_counter->counter, dimension_index, 1);
6566528b FD	339	if (ret)
	340	WARN_ON_ONCE(1);
	341	}
	342
d37ecb3f	343	static
6566528b	344	void notification_send(struct lttng_event_notifier_notification *notif,
cda77256	345	const struct lttng_ust_event_notifier *event_notifier)
d37ecb3f FD	346	{
	347	ssize_t ret;
	348	size_t content_len;
	349	int iovec_count = 1;
fd17d7ce	350	struct lttng_ust_abi_event_notifier_notification ust_notif = {0};
d37ecb3f FD	351	struct iovec iov[2];
	352
	353	assert(notif);
	354
115db533	355	ust_notif.token = event_notifier->priv->parent.user_token;
d37ecb3f	356
d8d2416d	357	/*
d37ecb3f FD	358	* Prepare sending the notification from multiple buffers using an
	359	* array of `struct iovec`. The first buffer of the vector is
	360	* notification structure itself and is always present.
d8d2416d	361	*/
d37ecb3f FD	362	iov[0].iov_base = &ust_notif;
	363	iov[0].iov_len = sizeof(ust_notif);
	364
	365	if (notif->has_captures) {
	366	/*
	367	* If captures were requested, the second buffer of the array
	368	* is the capture buffer.
	369	*/
	370	assert(notif->writer.buffer);
	371	content_len = notif->writer.write_pos - notif->writer.buffer;
d8d2416d	372
d37ecb3f	373	assert(content_len > 0 && content_len <= CAPTURE_BUFFER_SIZE);
d8d2416d	374
d37ecb3f FD	375	iov[1].iov_base = notif->capture_buf;
	376	iov[1].iov_len = content_len;
	377
	378	iovec_count++;
	379	} else {
	380	content_len = 0;
	381	}
	382
	383	/*
	384	* Update the capture buffer size so that receiver of the buffer will
	385	* know how much to expect.
	386	*/
	387	ust_notif.capture_buf_size = content_len;
d8d2416d	388
d37ecb3f	389	/* Send all the buffers. */
516d12da	390	ret = ust_patient_writev(notif->notification_fd, iov, iovec_count);
d8d2416d FD	391	if (ret == -1) {
d8d2416d FD	392	if (errno == EAGAIN) {
6566528b FD	393	record_error(event_notifier);
6566528b FD	394	DBG("Cannot send event_notifier notification without blocking: %s",
d8d2416d FD	395	strerror(errno));
	396	} else {
	397	DBG("Error to sending event notifier notification: %s",
	398	strerror(errno));
	399	abort();
	400	}
	401	}
	402	}
d37ecb3f	403
6566528b	404	void lttng_event_notifier_notification_send(
cda77256	405	const struct lttng_ust_event_notifier *event_notifier,
a2e4d05e	406	const char *stack_data,
b2e37d27	407	struct lttng_ust_probe_ctx *probe_ctx,
a2e4d05e	408	struct lttng_ust_notification_ctx *notif_ctx)
d37ecb3f FD	409	{
	410	/*
	411	* This function is called from the probe, we must do dynamic
	412	* allocation in this context.
	413	*/
	414	struct lttng_event_notifier_notification notif = {0};
	415
c651e872 MD	416	if (notification_init(&notif, event_notifier)) {
	417	record_error(event_notifier);
	418	goto end;
	419	}
d37ecb3f	420
a2e4d05e	421	if (caa_unlikely(notif_ctx->eval_capture)) {
5469a374	422	struct lttng_ust_bytecode_runtime *capture_bc_runtime;
d37ecb3f FD	423
	424	/*
	425	* Iterate over all the capture bytecodes. If the interpreter
	426	* functions returns successfully, append the value of the
	427	* `output` parameter to the capture buffer. If the interpreter
	428	* fails, append an empty capture to the buffer.
	429	*/
a2e4d05e MD	430	cds_list_for_each_entry_rcu(capture_bc_runtime,
a2e4d05e MD	431	&event_notifier->priv->capture_bytecode_runtime_head, node) {
d37ecb3f	432	struct lttng_interpreter_output output;
c651e872 MD	433	uint8_t *save_pos;
c651e872 MD	434	int ret;
d37ecb3f	435
c651e872	436	lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
22c30e27	437	if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
b2e37d27	438	stack_data, probe_ctx, &output) == LTTNG_UST_BYTECODE_INTERPRETER_OK)
c651e872	439	ret = notification_append_capture(&notif, &output);
d37ecb3f	440	else
c651e872 MD	441	ret = notification_append_empty_capture(&notif);
	442	if (ret) {
	443	/*
	444	* On append capture error, skip the field
	445	* capture by restoring the msgpack writer
	446	* position.
	447	*/
	448	lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
	449	}
d37ecb3f FD	450	}
	451	}
	452
	453	/*
	454	* Send the notification (including the capture buffer) to the
	455	* sessiond.
	456	*/
6566528b	457	notification_send(&notif, event_notifier);
c651e872 MD	458	end:
c651e872 MD	459	return;
d37ecb3f	460	}