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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-event-notifier-notification.c
 *
 * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
 */

#include <linux/bug.h>

#include <lttng/lttng-bytecode.h>
#include <lttng/events.h>
#include <lttng/msgpack.h>
#include <lttng/event-notifier-notification.h>
#include <lttng/events-internal.h>
#include <lttng/probe-user.h>
#include <wrapper/barrier.h>

/*
 * The capture buffer size needs to be below 1024 bytes to avoid the
 * frame to be larger than the 1024 limit enforced by the kernel. If we
 * ever need to increase it, we will need to use a memory allocation
 * scheme which allows allocating temporary memory chunks from the
 * instrumentation sites. This could be done by adapting lttng
 * tp-mempool to become nmi-safe and lock-free.
 */
#define CAPTURE_BUFFER_SIZE 512

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;

	/*
	 * Enums are captured as a map containing 2 key-value pairs. Such as:
	 * - type: enum
	 *   value: 177
	 */
	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:
		WARN_ON_ONCE(1);
	}

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

static
int64_t capture_sequence_element_signed(uint8_t *ptr,
		const struct lttng_kernel_type_integer *type)
{
	int64_t value = 0;
	unsigned int size = type->size;
	bool user = type->user;
	bool byte_order_reversed = type->reverse_byte_order;

	switch (size) {
	case 8:
	{
		int8_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int8_t)))
				tmp = 0;
		} else {
			tmp = *ptr;
		}
		value = tmp;
		break;
	}
	case 16:
	{
		int16_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int16_t)))
				tmp = 0;
		} else {
			tmp = *(int16_t *) ptr;
		}
		if (byte_order_reversed)
			__swab16s(&tmp);
		value = tmp;
		break;
	}
	case 32:
	{
		int32_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int32_t)))
				tmp = 0;
		} else {
			tmp = *(int32_t *) ptr;
		}
		if (byte_order_reversed)
			__swab32s(&tmp);
		value = tmp;
		break;
	}
	case 64:
	{
		int64_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int64_t)))
				tmp = 0;
		} else {
			tmp = *(int64_t *) ptr;
		}
		if (byte_order_reversed)
			__swab64s(&tmp);
		value = tmp;
		break;
	}
	default:
		WARN_ON_ONCE(1);
	}

	return value;
}

static
uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
		const struct lttng_kernel_type_integer *type)
{
	uint64_t value = 0;
	unsigned int size = type->size;
	bool user = type->user;
	bool byte_order_reversed = type->reverse_byte_order;

	switch (size) {
	case 8:
	{
		uint8_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint8_t)))
				tmp = 0;
		} else {
			tmp = *ptr;
		}
		value = tmp;
		break;
	}
	case 16:
	{
		uint16_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint16_t)))
				tmp = 0;
		} else {
			tmp = *(uint16_t *) ptr;
		}
		if (byte_order_reversed)
			__swab16s(&tmp);
		value = tmp;
		break;
	}
	case 32:
	{
		uint32_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint32_t)))
				tmp = 0;
		} else {
			tmp = *(uint32_t *) ptr;
		}
		if (byte_order_reversed)
			__swab32s(&tmp);
		value = tmp;
		break;
	}
	case 64:
	{
		uint64_t tmp;

		if (user) {
			if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint64_t)))
				tmp = 0;
		} else {
			tmp = *(uint64_t *) ptr;
		}
		if (byte_order_reversed)
			__swab64s(&tmp);
		value = tmp;
		break;
	}
	default:
		WARN_ON_ONCE(1);
	}

	return value;
}

int capture_sequence(struct lttng_msgpack_writer *writer,
		struct lttng_interpreter_output *output)
{
	const struct lttng_kernel_type_integer *integer_type = NULL;
	const struct lttng_kernel_type_common *nested_type;
	uint8_t *ptr;
	bool signedness;
	int ret, i;

	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_kernel_type_integer:
		integer_type = lttng_kernel_get_type_integer(nested_type);
		break;
	case lttng_kernel_type_enum:
		/* Treat enumeration as an integer. */
		integer_type = lttng_kernel_get_type_integer(lttng_kernel_get_type_enum(nested_type)->container_type);
		break;
	default:
		/* Capture of array of non-integer are not supported. */
		WARN_ON_ONCE(1);
		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));
			if (ret) {
				goto end;
			}
		} 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 arithmetics below to
		 * take into account that the next element might be further
		 * away.
		 */
		WARN_ON_ONCE(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_append_capture(
		struct lttng_event_notifier_notification *notif,
		struct lttng_interpreter_output *output)
{
	struct lttng_msgpack_writer *writer = &notif->writer;
	int ret = 0;

	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_STRING:
		if (output->u.str.user) {
			ret = lttng_msgpack_write_user_str(writer, output->u.str.user_str);
		} else {
			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:
		ret = -1;
		WARN_ON_ONCE(1);
	}
	return ret;
}

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

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

	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
void record_error(struct lttng_kernel_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;

	/*
	 * lttng_smp_load_acquire paired with lttng_smp_store_release orders
	 * creation of the error counter and setting error_counter_len
	 * before the error_counter is used.
	 */
	error_counter = lttng_smp_load_acquire(&event_notifier_group->error_counter);
	/* 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 = 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,
		struct lttng_kernel_event_notifier *event_notifier)
{
	struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
	struct lttng_kernel_ring_buffer_ctx ctx;
	struct lttng_kernel_abi_event_notifier_notification kernel_notif;
	size_t capture_buffer_content_len, reserve_size;
	int ret;

	reserve_size = sizeof(kernel_notif);
	kernel_notif.token = event_notifier->priv->parent.user_token;

	if (notif->has_captures) {
		capture_buffer_content_len = notif->writer.write_pos - notif->writer.buffer;
	} else {
		capture_buffer_content_len = 0;
	}

	WARN_ON_ONCE(capture_buffer_content_len > CAPTURE_BUFFER_SIZE);

	reserve_size += capture_buffer_content_len;
	kernel_notif.capture_buf_size = capture_buffer_content_len;

	lib_ring_buffer_ctx_init(&ctx, event_notifier_group->chan, reserve_size,
			lttng_alignof(kernel_notif), NULL);
	ret = event_notifier_group->ops->event_reserve(&ctx);
	if (ret < 0) {
		record_error(event_notifier);
		return;
	}

	/* Write the notif structure. */
	event_notifier_group->ops->event_write(&ctx, &kernel_notif,
			sizeof(kernel_notif), lttng_alignof(kernel_notif));

	/*
	 * Write the capture buffer. No need to realigned as the below is a raw
	 * char* buffer.
	 */
	event_notifier_group->ops->event_write(&ctx, &notif->capture_buf,
			capture_buffer_content_len, 1);

	event_notifier_group->ops->event_commit(&ctx);
	irq_work_queue(&event_notifier_group->wakeup_pending);
}

void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *event_notifier,
		const char *stack_data,
		struct lttng_kernel_probe_ctx *probe_ctx,
		struct lttng_kernel_notification_ctx *notif_ctx)
{
	struct lttng_event_notifier_notification notif = { 0 };

	if (unlikely(!READ_ONCE(event_notifier->parent.enabled)))
		return;

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

	if (unlikely(notif_ctx->eval_capture)) {
		struct lttng_kernel_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.
		 */
		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_KERNEL_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
21f58fb7 FD	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
	2	*
	3	* lttng-event-notifier-notification.c
	4	*
	5	* Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
	6	*/
	7
42f3ef8c FD	8	#include <linux/bug.h>
	9
	10	#include <lttng/lttng-bytecode.h>
21f58fb7	11	#include <lttng/events.h>
42f3ef8c	12	#include <lttng/msgpack.h>
21f58fb7	13	#include <lttng/event-notifier-notification.h>
437d5aa5	14	#include <lttng/events-internal.h>
11b589f6	15	#include <lttng/probe-user.h>
6657edec	16	#include <wrapper/barrier.h>
21f58fb7	17
99d223ad	18	/*
e699ee6c MD	19	* The capture buffer size needs to be below 1024 bytes to avoid the
	20	* frame to be larger than the 1024 limit enforced by the kernel. If we
	21	* ever need to increase it, we will need to use a memory allocation
	22	* scheme which allows allocating temporary memory chunks from the
	23	* instrumentation sites. This could be done by adapting lttng
	24	* tp-mempool to become nmi-safe and lock-free.
99d223ad FD	25	*/
	26	#define CAPTURE_BUFFER_SIZE 512
	27
	28	struct lttng_event_notifier_notification {
	29	int notification_fd;
	30	uint64_t event_notifier_token;
	31	uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
	32	struct lttng_msgpack_writer writer;
	33	bool has_captures;
	34	};
	35
42f3ef8c FD	36	static
	37	int capture_enum(struct lttng_msgpack_writer *writer,
	38	struct lttng_interpreter_output *output)
	39	{
	40	int ret;
	41
	42	/*
	43	* Enums are captured as a map containing 2 key-value pairs. Such as:
	44	* - type: enum
	45	* value: 177
	46	*/
	47	ret = lttng_msgpack_begin_map(writer, 2);
	48	if (ret) {
42f3ef8c FD	49	goto end;
	50	}
	51
	52	ret = lttng_msgpack_write_str(writer, "type");
	53	if (ret) {
42f3ef8c FD	54	goto end;
	55	}
	56
	57	ret = lttng_msgpack_write_str(writer, "enum");
	58	if (ret) {
42f3ef8c FD	59	goto end;
	60	}
	61
	62	ret = lttng_msgpack_write_str(writer, "value");
	63	if (ret) {
42f3ef8c FD	64	goto end;
	65	}
	66
	67	switch (output->type) {
	68	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	69	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
	70	if (ret) {
42f3ef8c FD	71	goto end;
	72	}
	73	break;
	74	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
	75	ret = lttng_msgpack_write_signed_integer(writer, output->u.u);
	76	if (ret) {
42f3ef8c FD	77	goto end;
	78	}
	79	break;
	80	default:
736f2dd6	81	WARN_ON_ONCE(1);
42f3ef8c FD	82	}
	83
	84	ret = lttng_msgpack_end_map(writer);
42f3ef8c FD	85	end:
	86	return ret;
	87	}
	88
	89	static
	90	int64_t capture_sequence_element_signed(uint8_t *ptr,
437d5aa5	91	const struct lttng_kernel_type_integer *type)
42f3ef8c FD	92	{
	93	int64_t value = 0;
	94	unsigned int size = type->size;
11b589f6	95	bool user = type->user;
42f3ef8c FD	96	bool byte_order_reversed = type->reverse_byte_order;
	97
	98	switch (size) {
	99	case 8:
11b589f6 MD	100	{
	101	int8_t tmp;
	102
	103	if (user) {
	104	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int8_t)))
	105	tmp = 0;
	106	} else {
	107	tmp = *ptr;
	108	}
	109	value = tmp;
42f3ef8c	110	break;
11b589f6	111	}
42f3ef8c FD	112	case 16:
	113	{
	114	int16_t tmp;
11b589f6 MD	115
	116	if (user) {
	117	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int16_t)))
	118	tmp = 0;
	119	} else {
	120	tmp = (int16_t ) ptr;
	121	}
42f3ef8c FD	122	if (byte_order_reversed)
42f3ef8c FD	123	__swab16s(&tmp);
42f3ef8c FD	124	value = tmp;
	125	break;
	126	}
	127	case 32:
	128	{
	129	int32_t tmp;
11b589f6 MD	130
	131	if (user) {
	132	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int32_t)))
	133	tmp = 0;
	134	} else {
	135	tmp = (int32_t ) ptr;
	136	}
42f3ef8c FD	137	if (byte_order_reversed)
42f3ef8c FD	138	__swab32s(&tmp);
42f3ef8c FD	139	value = tmp;
	140	break;
	141	}
	142	case 64:
	143	{
	144	int64_t tmp;
11b589f6 MD	145
	146	if (user) {
	147	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int64_t)))
	148	tmp = 0;
	149	} else {
	150	tmp = (int64_t ) ptr;
	151	}
42f3ef8c FD	152	if (byte_order_reversed)
42f3ef8c FD	153	__swab64s(&tmp);
42f3ef8c FD	154	value = tmp;
	155	break;
	156	}
	157	default:
736f2dd6	158	WARN_ON_ONCE(1);
42f3ef8c FD	159	}
	160
	161	return value;
	162	}
	163
	164	static
	165	uint64_t capture_sequence_element_unsigned(uint8_t *ptr,
437d5aa5	166	const struct lttng_kernel_type_integer *type)
42f3ef8c FD	167	{
	168	uint64_t value = 0;
	169	unsigned int size = type->size;
11b589f6	170	bool user = type->user;
42f3ef8c FD	171	bool byte_order_reversed = type->reverse_byte_order;
	172
	173	switch (size) {
	174	case 8:
11b589f6 MD	175	{
	176	uint8_t tmp;
	177
	178	if (user) {
	179	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint8_t)))
	180	tmp = 0;
	181	} else {
	182	tmp = *ptr;
	183	}
	184	value = tmp;
42f3ef8c	185	break;
11b589f6	186	}
42f3ef8c FD	187	case 16:
	188	{
	189	uint16_t tmp;
11b589f6 MD	190
	191	if (user) {
	192	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint16_t)))
	193	tmp = 0;
	194	} else {
	195	tmp = (uint16_t ) ptr;
	196	}
42f3ef8c FD	197	if (byte_order_reversed)
42f3ef8c FD	198	__swab16s(&tmp);
42f3ef8c FD	199	value = tmp;
	200	break;
	201	}
	202	case 32:
	203	{
	204	uint32_t tmp;
11b589f6 MD	205
	206	if (user) {
	207	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint32_t)))
	208	tmp = 0;
	209	} else {
	210	tmp = (uint32_t ) ptr;
	211	}
42f3ef8c FD	212	if (byte_order_reversed)
42f3ef8c FD	213	__swab32s(&tmp);
42f3ef8c FD	214	value = tmp;
	215	break;
	216	}
	217	case 64:
	218	{
	219	uint64_t tmp;
11b589f6 MD	220
	221	if (user) {
	222	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint64_t)))
	223	tmp = 0;
	224	} else {
	225	tmp = (uint64_t ) ptr;
	226	}
42f3ef8c FD	227	if (byte_order_reversed)
42f3ef8c FD	228	__swab64s(&tmp);
42f3ef8c FD	229	value = tmp;
	230	break;
	231	}
	232	default:
736f2dd6	233	WARN_ON_ONCE(1);
42f3ef8c FD	234	}
	235
	236	return value;
	237	}
	238
42f3ef8c FD	239	int capture_sequence(struct lttng_msgpack_writer *writer,
	240	struct lttng_interpreter_output *output)
	241	{
437d5aa5 MD	242	const struct lttng_kernel_type_integer *integer_type = NULL;
437d5aa5 MD	243	const struct lttng_kernel_type_common *nested_type;
42f3ef8c FD	244	uint8_t *ptr;
	245	bool signedness;
	246	int ret, i;
	247
	248	ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
	249	if (ret) {
42f3ef8c FD	250	goto end;
	251	}
	252
	253	ptr = (uint8_t *) output->u.sequence.ptr;
	254	nested_type = output->u.sequence.nested_type;
12bb2edb MD	255	switch (nested_type->type) {
12bb2edb MD	256	case lttng_kernel_type_integer:
437d5aa5	257	integer_type = lttng_kernel_get_type_integer(nested_type);
42f3ef8c	258	break;
437d5aa5	259	case lttng_kernel_type_enum:
42f3ef8c	260	/* Treat enumeration as an integer. */
437d5aa5	261	integer_type = lttng_kernel_get_type_integer(lttng_kernel_get_type_enum(nested_type)->container_type);
42f3ef8c FD	262	break;
	263	default:
	264	/* Capture of array of non-integer are not supported. */
736f2dd6 MD	265	WARN_ON_ONCE(1);
	266	ret = -1;
	267	goto end;
42f3ef8c FD	268	}
	269	signedness = integer_type->signedness;
	270	for (i = 0; i < output->u.sequence.nr_elem; i++) {
	271	if (signedness) {
	272	ret = lttng_msgpack_write_signed_integer(writer,
	273	capture_sequence_element_signed(ptr, integer_type));
	274	if (ret) {
42f3ef8c FD	275	goto end;
	276	}
	277	} else {
	278	ret = lttng_msgpack_write_unsigned_integer(writer,
	279	capture_sequence_element_unsigned(ptr, integer_type));
	280	if (ret) {
42f3ef8c FD	281	goto end;
	282	}
	283	}
	284
	285	/*
	286	* We assume that alignment is smaller or equal to the size.
	287	* This currently holds true but if it changes in the future,
	288	* we will want to change the pointer arithmetics below to
	289	* take into account that the next element might be further
	290	* away.
	291	*/
736f2dd6	292	WARN_ON_ONCE(integer_type->alignment > integer_type->size);
42f3ef8c FD	293
	294	/* Size is in number of bits. */
	295	ptr += (integer_type->size / CHAR_BIT) ;
	296	}
	297
	298	ret = lttng_msgpack_end_array(writer);
42f3ef8c FD	299	end:
	300	return ret;
	301	}
	302
99d223ad FD	303	static
	304	int notification_append_capture(
	305	struct lttng_event_notifier_notification *notif,
	306	struct lttng_interpreter_output *output)
	307	{
	308	struct lttng_msgpack_writer *writer = &notif->writer;
	309	int ret = 0;
	310
	311	switch (output->type) {
	312	case LTTNG_INTERPRETER_TYPE_S64:
	313	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
99d223ad FD	314	break;
	315	case LTTNG_INTERPRETER_TYPE_U64:
	316	ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u);
99d223ad FD	317	break;
99d223ad FD	318	case LTTNG_INTERPRETER_TYPE_STRING:
8915cf5e MD	319	if (output->u.str.user) {
	320	ret = lttng_msgpack_write_user_str(writer, output->u.str.user_str);
	321	} else {
	322	ret = lttng_msgpack_write_str(writer, output->u.str.str);
	323	}
99d223ad FD	324	break;
	325	case LTTNG_INTERPRETER_TYPE_SEQUENCE:
	326	ret = capture_sequence(writer, output);
99d223ad FD	327	break;
	328	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	329	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
	330	ret = capture_enum(writer, output);
99d223ad FD	331	break;
	332	default:
	333	ret = -1;
736f2dd6	334	WARN_ON_ONCE(1);
99d223ad	335	}
99d223ad FD	336	return ret;
	337	}
	338
	339	static
	340	int notification_append_empty_capture(
	341	struct lttng_event_notifier_notification *notif)
	342	{
736f2dd6	343	return lttng_msgpack_write_nil(&notif->writer);
99d223ad FD	344	}
	345
	346	static
	347	int notification_init(struct lttng_event_notifier_notification *notif,
a67ba386	348	struct lttng_kernel_event_notifier *event_notifier)
99d223ad FD	349	{
	350	struct lttng_msgpack_writer *writer = &notif->writer;
	351	int ret = 0;
	352
	353	notif->has_captures = false;
	354
a67ba386	355	if (event_notifier->priv->num_captures > 0) {
99d223ad FD	356	lttng_msgpack_writer_init(writer, notif->capture_buf,
	357	CAPTURE_BUFFER_SIZE);
	358
a67ba386	359	ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
99d223ad	360	if (ret) {
99d223ad FD	361	goto end;
	362	}
	363
	364	notif->has_captures = true;
	365	}
	366
	367	end:
	368	return ret;
	369	}
	370
99f52fcc	371	static
a67ba386	372	void record_error(struct lttng_kernel_event_notifier *event_notifier)
99f52fcc FD	373	{
99f52fcc FD	374
a67ba386	375	struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
ab04d7b1	376	struct lttng_counter *error_counter;
99f52fcc FD	377	size_t dimension_index[1];
	378	int ret;
	379
ab04d7b1	380	/*
6657edec	381	* lttng_smp_load_acquire paired with lttng_smp_store_release orders
ab04d7b1 MD	382	* creation of the error counter and setting error_counter_len
	383	* before the error_counter is used.
	384	*/
6657edec	385	error_counter = lttng_smp_load_acquire(&event_notifier_group->error_counter);
a83d6831	386	/* This group may not have an error counter attached to it. */
ab04d7b1	387	if (!error_counter)
a83d6831 FD	388	return;
a83d6831 FD	389
a67ba386	390	dimension_index[0] = event_notifier->priv->error_counter_index;
99f52fcc	391
ab04d7b1	392	ret = error_counter->ops->counter_add(error_counter->counter,
99f52fcc FD	393	dimension_index, 1);
	394	if (ret)
	395	WARN_ON_ONCE(1);
	396	}
	397
99d223ad FD	398	static
99d223ad FD	399	void notification_send(struct lttng_event_notifier_notification *notif,
a67ba386	400	struct lttng_kernel_event_notifier *event_notifier)
21f58fb7	401	{
a67ba386	402	struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
8a57ec02	403	struct lttng_kernel_ring_buffer_ctx ctx;
606828e4	404	struct lttng_kernel_abi_event_notifier_notification kernel_notif;
99d223ad	405	size_t capture_buffer_content_len, reserve_size;
21f58fb7 FD	406	int ret;
21f58fb7 FD	407
99d223ad	408	reserve_size = sizeof(kernel_notif);
a67ba386	409	kernel_notif.token = event_notifier->priv->parent.user_token;
21f58fb7	410
99d223ad FD	411	if (notif->has_captures) {
	412	capture_buffer_content_len = notif->writer.write_pos - notif->writer.buffer;
	413	} else {
	414	capture_buffer_content_len = 0;
	415	}
	416
	417	WARN_ON_ONCE(capture_buffer_content_len > CAPTURE_BUFFER_SIZE);
	418
	419	reserve_size += capture_buffer_content_len;
	420	kernel_notif.capture_buf_size = capture_buffer_content_len;
	421
8a445457	422	lib_ring_buffer_ctx_init(&ctx, event_notifier_group->chan, reserve_size,
b1199bd3	423	lttng_alignof(kernel_notif), NULL);
c2fb9c1c	424	ret = event_notifier_group->ops->event_reserve(&ctx);
21f58fb7	425	if (ret < 0) {
99f52fcc	426	record_error(event_notifier);
21f58fb7 FD	427	return;
21f58fb7 FD	428	}
99d223ad	429
99d223ad FD	430	/* Write the notif structure. */
99d223ad FD	431	event_notifier_group->ops->event_write(&ctx, &kernel_notif,
f5ffbd77	432	sizeof(kernel_notif), lttng_alignof(kernel_notif));
99d223ad FD	433
	434	/*
	435	* Write the capture buffer. No need to realigned as the below is a raw
	436	* char* buffer.
	437	*/
	438	event_notifier_group->ops->event_write(&ctx, &notif->capture_buf,
f5ffbd77	439	capture_buffer_content_len, 1);
99d223ad	440
21f58fb7 FD	441	event_notifier_group->ops->event_commit(&ctx);
	442	irq_work_queue(&event_notifier_group->wakeup_pending);
	443	}
99d223ad	444
a67ba386	445	void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *event_notifier,
c3eddb2e	446	const char *stack_data,
a92e844e	447	struct lttng_kernel_probe_ctx *probe_ctx,
a67ba386	448	struct lttng_kernel_notification_ctx *notif_ctx)
99d223ad FD	449	{
99d223ad FD	450	struct lttng_event_notifier_notification notif = { 0 };
99d223ad	451
a67ba386	452	if (unlikely(!READ_ONCE(event_notifier->parent.enabled)))
99d223ad FD	453	return;
99d223ad FD	454
736f2dd6 MD	455	if (notification_init(&notif, event_notifier)) {
736f2dd6 MD	456	record_error(event_notifier);
99d223ad FD	457	goto end;
	458	}
	459
c3eddb2e	460	if (unlikely(notif_ctx->eval_capture)) {
218585b9	461	struct lttng_kernel_bytecode_runtime *capture_bc_runtime;
99d223ad FD	462
	463	/*
	464	* Iterate over all the capture bytecodes. If the interpreter
	465	* functions returns successfully, append the value of the
	466	* `output` parameter to the capture buffer. If the interpreter
	467	* fails, append an empty capture to the buffer.
	468	*/
c3eddb2e	469	list_for_each_entry_rcu(capture_bc_runtime,
a67ba386	470	&event_notifier->priv->capture_bytecode_runtime_head, node) {
99d223ad	471	struct lttng_interpreter_output output;
736f2dd6 MD	472	uint8_t *save_pos;
736f2dd6 MD	473	int ret;
99d223ad	474
736f2dd6	475	lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
8a445457 MD	476	if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
8a445457 MD	477	stack_data, probe_ctx, &output) == LTTNG_KERNEL_BYTECODE_INTERPRETER_OK)
99d223ad FD	478	ret = notification_append_capture(&notif, &output);
	479	else
	480	ret = notification_append_empty_capture(&notif);
736f2dd6 MD	481	if (ret) {
	482	/*
	483	* On append capture error, skip the field
	484	* capture by restoring the msgpack writer
	485	* position.
	486	*/
	487	lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
	488	}
99d223ad FD	489	}
	490	}
	491
	492	/*
	493	* Send the notification (including the capture buffer) to the
	494	* sessiond.
	495	*/
	496	notification_send(&notif, event_notifier);
	497	end:
	498	return;
	499	}