[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 <asm/barrier.h>
#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>

/*
 * 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

#define MSG_WRITE_NIL_LEN 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;

	/*
	 * 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 = -1;
		goto end;
	}

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

static
int capture_sequence_element_signed(uint8_t *ptr,
		const struct lttng_kernel_type_integer *type,
		int64_t *_value)
{
	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)))
				return -1;
		} 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)))
				return -1;
		} 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)))
				return -1;
		} 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)))
				return -1;
		} else {
			tmp = *(int64_t *) ptr;
		}
		if (byte_order_reversed)
			__swab64s(&tmp);
		value = tmp;
		break;
	}
	default:
		WARN_ON_ONCE(1);
		return -1;
	}

	*_value = value;
	return 0;
}

static
int capture_sequence_element_unsigned(uint8_t *ptr,
		const struct lttng_kernel_type_integer *type,
		uint64_t *_value)
{
	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)))
				return -1;
		} 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)))
				return -1;
		} 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)))
				return -1;
		} 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)))
				return -1;
		} else {
			tmp = *(uint64_t *) ptr;
		}
		if (byte_order_reversed)
			__swab64s(&tmp);
		value = tmp;
		break;
	}
	default:
		WARN_ON_ONCE(1);
		return -1;
	}

	*_value = value;
	return 0;
}

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) {
			int64_t v;

			ret = capture_sequence_element_signed(ptr, integer_type, &v);
			if (ret) {
				goto end;
			}
			ret = lttng_msgpack_write_signed_integer(writer, v);
			if (ret) {
				goto end;
			}
		} else {
			uint64_t v;

			ret = capture_sequence_element_unsigned(ptr, integer_type, &v);
			if (ret) {
				goto end;
			}
			ret = lttng_msgpack_write_unsigned_integer(writer, v);
			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;

	/*
	 * smp_load_acquire paired with smp_store_release orders creation of
	 * the error counter and setting error_counter_len before the
	 * error_counter is used.
	 */
	error_counter = 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);
}

/*
 * Validate that the buffer has enough room to hold empty capture fields.
 */
static
bool validate_buffer_len(struct lttng_event_notifier_notification *notif, size_t captures_left)
{
	if (notif->writer.end_write_pos - notif->writer.write_pos < MSG_WRITE_NIL_LEN * captures_left)
		return false;
	return true;
}

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 };
	size_t captures_left;

	if (notification_init(&notif, event_notifier))
		goto error;

	captures_left = event_notifier->priv->num_captures;
	if (!validate_buffer_len(&notif, captures_left))
		goto error;

	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 = -1;

			lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
			captures_left--;
			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);
			if (ret || !validate_buffer_len(&notif, captures_left)) {
				/*
				 * On append capture error or if the generated
				 * buffer data would not leave enough room to
				 * write empty capture fields for the remaining
				 * fields, skip the field capture by restoring
				 * the msgpack writer position and writing an
				 * empty capture field.
				 */
				lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
				ret = notification_append_empty_capture(&notif);
				WARN_ON_ONCE(ret);
			}
		}
	}

	if (notif.has_captures && lttng_msgpack_end_array(&notif.writer))
		goto error;

	/*
	 * Send the notification (including the capture buffer) to the
	 * sessiond.
	 */
	notification_send(&notif, event_notifier);
	return;

error:
	record_error(event_notifier);
	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
a27c8df7	8	#include <asm/barrier.h>
42f3ef8c FD	9	#include <linux/bug.h>
	10
	11	#include <lttng/lttng-bytecode.h>
21f58fb7	12	#include <lttng/events.h>
42f3ef8c	13	#include <lttng/msgpack.h>
21f58fb7	14	#include <lttng/event-notifier-notification.h>
437d5aa5	15	#include <lttng/events-internal.h>
11b589f6	16	#include <lttng/probe-user.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
f125ded4 MD	28	#define MSG_WRITE_NIL_LEN 1
f125ded4 MD	29
99d223ad FD	30	struct lttng_event_notifier_notification {
	31	int notification_fd;
	32	uint64_t event_notifier_token;
	33	uint8_t capture_buf[CAPTURE_BUFFER_SIZE];
	34	struct lttng_msgpack_writer writer;
	35	bool has_captures;
	36	};
	37
42f3ef8c FD	38	static
	39	int capture_enum(struct lttng_msgpack_writer *writer,
	40	struct lttng_interpreter_output *output)
	41	{
	42	int ret;
	43
	44	/*
	45	* Enums are captured as a map containing 2 key-value pairs. Such as:
	46	* - type: enum
	47	* value: 177
	48	*/
	49	ret = lttng_msgpack_begin_map(writer, 2);
	50	if (ret) {
42f3ef8c FD	51	goto end;
	52	}
	53
	54	ret = lttng_msgpack_write_str(writer, "type");
	55	if (ret) {
42f3ef8c FD	56	goto end;
	57	}
	58
	59	ret = lttng_msgpack_write_str(writer, "enum");
	60	if (ret) {
42f3ef8c FD	61	goto end;
	62	}
	63
	64	ret = lttng_msgpack_write_str(writer, "value");
	65	if (ret) {
42f3ef8c FD	66	goto end;
	67	}
	68
	69	switch (output->type) {
	70	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	71	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
	72	if (ret) {
42f3ef8c FD	73	goto end;
	74	}
	75	break;
	76	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
	77	ret = lttng_msgpack_write_signed_integer(writer, output->u.u);
	78	if (ret) {
42f3ef8c FD	79	goto end;
	80	}
	81	break;
	82	default:
736f2dd6	83	WARN_ON_ONCE(1);
60ae08f0 MD	84	ret = -1;
60ae08f0 MD	85	goto end;
42f3ef8c FD	86	}
	87
	88	ret = lttng_msgpack_end_map(writer);
42f3ef8c FD	89	end:
	90	return ret;
	91	}
	92
	93	static
60ae08f0 MD	94	int capture_sequence_element_signed(uint8_t *ptr,
	95	const struct lttng_kernel_type_integer *type,
	96	int64_t *_value)
42f3ef8c FD	97	{
	98	int64_t value = 0;
	99	unsigned int size = type->size;
11b589f6	100	bool user = type->user;
42f3ef8c FD	101	bool byte_order_reversed = type->reverse_byte_order;
	102
	103	switch (size) {
	104	case 8:
11b589f6 MD	105	{
	106	int8_t tmp;
	107
	108	if (user) {
	109	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int8_t)))
60ae08f0	110	return -1;
11b589f6 MD	111	} else {
	112	tmp = *ptr;
	113	}
	114	value = tmp;
42f3ef8c	115	break;
11b589f6	116	}
42f3ef8c FD	117	case 16:
	118	{
	119	int16_t tmp;
11b589f6 MD	120
	121	if (user) {
	122	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int16_t)))
60ae08f0	123	return -1;
11b589f6 MD	124	} else {
	125	tmp = (int16_t ) ptr;
	126	}
42f3ef8c FD	127	if (byte_order_reversed)
42f3ef8c FD	128	__swab16s(&tmp);
42f3ef8c FD	129	value = tmp;
	130	break;
	131	}
	132	case 32:
	133	{
	134	int32_t tmp;
11b589f6 MD	135
	136	if (user) {
	137	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int32_t)))
60ae08f0	138	return -1;
11b589f6 MD	139	} else {
	140	tmp = (int32_t ) ptr;
	141	}
42f3ef8c FD	142	if (byte_order_reversed)
42f3ef8c FD	143	__swab32s(&tmp);
42f3ef8c FD	144	value = tmp;
	145	break;
	146	}
	147	case 64:
	148	{
	149	int64_t tmp;
11b589f6 MD	150
	151	if (user) {
	152	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(int64_t)))
60ae08f0	153	return -1;
11b589f6 MD	154	} else {
	155	tmp = (int64_t ) ptr;
	156	}
42f3ef8c FD	157	if (byte_order_reversed)
42f3ef8c FD	158	__swab64s(&tmp);
42f3ef8c FD	159	value = tmp;
	160	break;
	161	}
	162	default:
736f2dd6	163	WARN_ON_ONCE(1);
60ae08f0	164	return -1;
42f3ef8c FD	165	}
42f3ef8c FD	166
60ae08f0 MD	167	*_value = value;
60ae08f0 MD	168	return 0;
42f3ef8c FD	169	}
	170
	171	static
60ae08f0 MD	172	int capture_sequence_element_unsigned(uint8_t *ptr,
	173	const struct lttng_kernel_type_integer *type,
	174	uint64_t *_value)
42f3ef8c FD	175	{
	176	uint64_t value = 0;
	177	unsigned int size = type->size;
11b589f6	178	bool user = type->user;
42f3ef8c FD	179	bool byte_order_reversed = type->reverse_byte_order;
	180
	181	switch (size) {
	182	case 8:
11b589f6 MD	183	{
	184	uint8_t tmp;
	185
	186	if (user) {
	187	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint8_t)))
60ae08f0	188	return -1;
11b589f6 MD	189	} else {
	190	tmp = *ptr;
	191	}
	192	value = tmp;
42f3ef8c	193	break;
11b589f6	194	}
42f3ef8c FD	195	case 16:
	196	{
	197	uint16_t tmp;
11b589f6 MD	198
	199	if (user) {
	200	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint16_t)))
60ae08f0	201	return -1;
11b589f6 MD	202	} else {
	203	tmp = (uint16_t ) ptr;
	204	}
42f3ef8c FD	205	if (byte_order_reversed)
42f3ef8c FD	206	__swab16s(&tmp);
42f3ef8c FD	207	value = tmp;
	208	break;
	209	}
	210	case 32:
	211	{
	212	uint32_t tmp;
11b589f6 MD	213
	214	if (user) {
	215	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint32_t)))
60ae08f0	216	return -1;
11b589f6 MD	217	} else {
	218	tmp = (uint32_t ) ptr;
	219	}
42f3ef8c FD	220	if (byte_order_reversed)
42f3ef8c FD	221	__swab32s(&tmp);
42f3ef8c FD	222	value = tmp;
	223	break;
	224	}
	225	case 64:
	226	{
	227	uint64_t tmp;
11b589f6 MD	228
	229	if (user) {
	230	if (lttng_copy_from_user_check_nofault(&tmp, ptr, sizeof(uint64_t)))
60ae08f0	231	return -1;
11b589f6 MD	232	} else {
	233	tmp = (uint64_t ) ptr;
	234	}
42f3ef8c FD	235	if (byte_order_reversed)
42f3ef8c FD	236	__swab64s(&tmp);
42f3ef8c FD	237	value = tmp;
	238	break;
	239	}
	240	default:
736f2dd6	241	WARN_ON_ONCE(1);
60ae08f0	242	return -1;
42f3ef8c FD	243	}
42f3ef8c FD	244
60ae08f0 MD	245	*_value = value;
60ae08f0 MD	246	return 0;
42f3ef8c FD	247	}
42f3ef8c FD	248
42f3ef8c FD	249	int capture_sequence(struct lttng_msgpack_writer *writer,
	250	struct lttng_interpreter_output *output)
	251	{
437d5aa5 MD	252	const struct lttng_kernel_type_integer *integer_type = NULL;
437d5aa5 MD	253	const struct lttng_kernel_type_common *nested_type;
42f3ef8c FD	254	uint8_t *ptr;
	255	bool signedness;
	256	int ret, i;
	257
	258	ret = lttng_msgpack_begin_array(writer, output->u.sequence.nr_elem);
	259	if (ret) {
42f3ef8c FD	260	goto end;
	261	}
	262
	263	ptr = (uint8_t *) output->u.sequence.ptr;
	264	nested_type = output->u.sequence.nested_type;
12bb2edb MD	265	switch (nested_type->type) {
12bb2edb MD	266	case lttng_kernel_type_integer:
437d5aa5	267	integer_type = lttng_kernel_get_type_integer(nested_type);
42f3ef8c	268	break;
437d5aa5	269	case lttng_kernel_type_enum:
42f3ef8c	270	/* Treat enumeration as an integer. */
437d5aa5	271	integer_type = lttng_kernel_get_type_integer(lttng_kernel_get_type_enum(nested_type)->container_type);
42f3ef8c FD	272	break;
	273	default:
	274	/* Capture of array of non-integer are not supported. */
736f2dd6 MD	275	WARN_ON_ONCE(1);
	276	ret = -1;
	277	goto end;
42f3ef8c FD	278	}
	279	signedness = integer_type->signedness;
	280	for (i = 0; i < output->u.sequence.nr_elem; i++) {
	281	if (signedness) {
60ae08f0 MD	282	int64_t v;
	283
	284	ret = capture_sequence_element_signed(ptr, integer_type, &v);
	285	if (ret) {
	286	goto end;
	287	}
	288	ret = lttng_msgpack_write_signed_integer(writer, v);
42f3ef8c	289	if (ret) {
42f3ef8c FD	290	goto end;
	291	}
	292	} else {
60ae08f0 MD	293	uint64_t v;
	294
	295	ret = capture_sequence_element_unsigned(ptr, integer_type, &v);
	296	if (ret) {
	297	goto end;
	298	}
	299	ret = lttng_msgpack_write_unsigned_integer(writer, v);
42f3ef8c	300	if (ret) {
42f3ef8c FD	301	goto end;
	302	}
	303	}
	304
	305	/*
	306	* We assume that alignment is smaller or equal to the size.
	307	* This currently holds true but if it changes in the future,
	308	* we will want to change the pointer arithmetics below to
	309	* take into account that the next element might be further
	310	* away.
	311	*/
736f2dd6	312	WARN_ON_ONCE(integer_type->alignment > integer_type->size);
42f3ef8c FD	313
	314	/* Size is in number of bits. */
	315	ptr += (integer_type->size / CHAR_BIT) ;
	316	}
	317
	318	ret = lttng_msgpack_end_array(writer);
42f3ef8c FD	319	end:
	320	return ret;
	321	}
	322
99d223ad FD	323	static
	324	int notification_append_capture(
	325	struct lttng_event_notifier_notification *notif,
	326	struct lttng_interpreter_output *output)
	327	{
	328	struct lttng_msgpack_writer *writer = &notif->writer;
	329	int ret = 0;
	330
	331	switch (output->type) {
	332	case LTTNG_INTERPRETER_TYPE_S64:
	333	ret = lttng_msgpack_write_signed_integer(writer, output->u.s);
99d223ad FD	334	break;
	335	case LTTNG_INTERPRETER_TYPE_U64:
	336	ret = lttng_msgpack_write_unsigned_integer(writer, output->u.u);
99d223ad FD	337	break;
99d223ad FD	338	case LTTNG_INTERPRETER_TYPE_STRING:
8915cf5e MD	339	if (output->u.str.user) {
	340	ret = lttng_msgpack_write_user_str(writer, output->u.str.user_str);
	341	} else {
	342	ret = lttng_msgpack_write_str(writer, output->u.str.str);
	343	}
99d223ad FD	344	break;
	345	case LTTNG_INTERPRETER_TYPE_SEQUENCE:
	346	ret = capture_sequence(writer, output);
99d223ad FD	347	break;
	348	case LTTNG_INTERPRETER_TYPE_SIGNED_ENUM:
	349	case LTTNG_INTERPRETER_TYPE_UNSIGNED_ENUM:
	350	ret = capture_enum(writer, output);
99d223ad FD	351	break;
	352	default:
	353	ret = -1;
736f2dd6	354	WARN_ON_ONCE(1);
99d223ad	355	}
99d223ad FD	356	return ret;
	357	}
	358
	359	static
	360	int notification_append_empty_capture(
	361	struct lttng_event_notifier_notification *notif)
	362	{
736f2dd6	363	return lttng_msgpack_write_nil(&notif->writer);
99d223ad FD	364	}
	365
	366	static
	367	int notification_init(struct lttng_event_notifier_notification *notif,
a67ba386	368	struct lttng_kernel_event_notifier *event_notifier)
99d223ad FD	369	{
	370	struct lttng_msgpack_writer *writer = &notif->writer;
	371	int ret = 0;
	372
	373	notif->has_captures = false;
	374
a67ba386	375	if (event_notifier->priv->num_captures > 0) {
99d223ad FD	376	lttng_msgpack_writer_init(writer, notif->capture_buf,
	377	CAPTURE_BUFFER_SIZE);
	378
a67ba386	379	ret = lttng_msgpack_begin_array(writer, event_notifier->priv->num_captures);
99d223ad	380	if (ret) {
99d223ad FD	381	goto end;
	382	}
	383
	384	notif->has_captures = true;
	385	}
	386
	387	end:
	388	return ret;
	389	}
	390
99f52fcc	391	static
a67ba386	392	void record_error(struct lttng_kernel_event_notifier *event_notifier)
99f52fcc FD	393	{
99f52fcc FD	394
a67ba386	395	struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
ab04d7b1	396	struct lttng_counter *error_counter;
99f52fcc FD	397	size_t dimension_index[1];
	398	int ret;
	399
ab04d7b1	400	/*
a27c8df7 MJ	401	* smp_load_acquire paired with smp_store_release orders creation of
	402	* the error counter and setting error_counter_len before the
	403	* error_counter is used.
ab04d7b1	404	*/
a27c8df7	405	error_counter = smp_load_acquire(&event_notifier_group->error_counter);
a83d6831	406	/* This group may not have an error counter attached to it. */
ab04d7b1	407	if (!error_counter)
a83d6831 FD	408	return;
a83d6831 FD	409
a67ba386	410	dimension_index[0] = event_notifier->priv->error_counter_index;
99f52fcc	411
ab04d7b1	412	ret = error_counter->ops->counter_add(error_counter->counter,
99f52fcc FD	413	dimension_index, 1);
	414	if (ret)
	415	WARN_ON_ONCE(1);
	416	}
	417
99d223ad FD	418	static
99d223ad FD	419	void notification_send(struct lttng_event_notifier_notification *notif,
a67ba386	420	struct lttng_kernel_event_notifier *event_notifier)
21f58fb7	421	{
a67ba386	422	struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
8a57ec02	423	struct lttng_kernel_ring_buffer_ctx ctx;
606828e4	424	struct lttng_kernel_abi_event_notifier_notification kernel_notif;
99d223ad	425	size_t capture_buffer_content_len, reserve_size;
21f58fb7 FD	426	int ret;
21f58fb7 FD	427
99d223ad	428	reserve_size = sizeof(kernel_notif);
a67ba386	429	kernel_notif.token = event_notifier->priv->parent.user_token;
21f58fb7	430
99d223ad FD	431	if (notif->has_captures) {
	432	capture_buffer_content_len = notif->writer.write_pos - notif->writer.buffer;
	433	} else {
	434	capture_buffer_content_len = 0;
	435	}
	436
	437	WARN_ON_ONCE(capture_buffer_content_len > CAPTURE_BUFFER_SIZE);
	438
	439	reserve_size += capture_buffer_content_len;
	440	kernel_notif.capture_buf_size = capture_buffer_content_len;
	441
8a445457	442	lib_ring_buffer_ctx_init(&ctx, event_notifier_group->chan, reserve_size,
b1199bd3	443	lttng_alignof(kernel_notif), NULL);
c2fb9c1c	444	ret = event_notifier_group->ops->event_reserve(&ctx);
21f58fb7	445	if (ret < 0) {
99f52fcc	446	record_error(event_notifier);
21f58fb7 FD	447	return;
21f58fb7 FD	448	}
99d223ad	449
99d223ad FD	450	/* Write the notif structure. */
99d223ad FD	451	event_notifier_group->ops->event_write(&ctx, &kernel_notif,
f5ffbd77	452	sizeof(kernel_notif), lttng_alignof(kernel_notif));
99d223ad FD	453
	454	/*
	455	* Write the capture buffer. No need to realigned as the below is a raw
	456	* char* buffer.
	457	*/
	458	event_notifier_group->ops->event_write(&ctx, &notif->capture_buf,
f5ffbd77	459	capture_buffer_content_len, 1);
99d223ad	460
21f58fb7 FD	461	event_notifier_group->ops->event_commit(&ctx);
	462	irq_work_queue(&event_notifier_group->wakeup_pending);
	463	}
99d223ad	464
f125ded4 MD	465	/*
	466	* Validate that the buffer has enough room to hold empty capture fields.
	467	*/
	468	static
	469	bool validate_buffer_len(struct lttng_event_notifier_notification *notif, size_t captures_left)
	470	{
	471	if (notif->writer.end_write_pos - notif->writer.write_pos < MSG_WRITE_NIL_LEN * captures_left)
	472	return false;
	473	return true;
	474	}
	475
a67ba386	476	void lttng_event_notifier_notification_send(struct lttng_kernel_event_notifier *event_notifier,
c3eddb2e	477	const char *stack_data,
a92e844e	478	struct lttng_kernel_probe_ctx *probe_ctx,
a67ba386	479	struct lttng_kernel_notification_ctx *notif_ctx)
99d223ad FD	480	{
99d223ad FD	481	struct lttng_event_notifier_notification notif = { 0 };
f125ded4	482	size_t captures_left;
99d223ad	483
f125ded4 MD	484	if (notification_init(&notif, event_notifier))
	485	goto error;
	486
	487	captures_left = event_notifier->priv->num_captures;
	488	if (!validate_buffer_len(&notif, captures_left))
	489	goto error;
99d223ad	490
c3eddb2e	491	if (unlikely(notif_ctx->eval_capture)) {
218585b9	492	struct lttng_kernel_bytecode_runtime *capture_bc_runtime;
99d223ad FD	493
	494	/*
	495	* Iterate over all the capture bytecodes. If the interpreter
	496	* functions returns successfully, append the value of the
	497	* `output` parameter to the capture buffer. If the interpreter
	498	* fails, append an empty capture to the buffer.
	499	*/
c3eddb2e	500	list_for_each_entry_rcu(capture_bc_runtime,
a67ba386	501	&event_notifier->priv->capture_bytecode_runtime_head, node) {
99d223ad	502	struct lttng_interpreter_output output;
736f2dd6	503	uint8_t *save_pos;
f125ded4	504	int ret = -1;
99d223ad	505
736f2dd6	506	lttng_msgpack_save_writer_pos(&notif.writer, &save_pos);
f125ded4	507	captures_left--;
8a445457 MD	508	if (capture_bc_runtime->interpreter_func(capture_bc_runtime,
8a445457 MD	509	stack_data, probe_ctx, &output) == LTTNG_KERNEL_BYTECODE_INTERPRETER_OK)
99d223ad	510	ret = notification_append_capture(&notif, &output);
f125ded4	511	if (ret \|\| !validate_buffer_len(&notif, captures_left)) {
736f2dd6	512	/*
f125ded4 MD	513	* On append capture error or if the generated
	514	* buffer data would not leave enough room to
	515	* write empty capture fields for the remaining
	516	* fields, skip the field capture by restoring
	517	* the msgpack writer position and writing an
	518	* empty capture field.
736f2dd6 MD	519	*/
736f2dd6 MD	520	lttng_msgpack_restore_writer_pos(&notif.writer, save_pos);
f125ded4 MD	521	ret = notification_append_empty_capture(&notif);
f125ded4 MD	522	WARN_ON_ONCE(ret);
736f2dd6	523	}
99d223ad FD	524	}
	525	}
	526
f125ded4 MD	527	if (notif.has_captures && lttng_msgpack_end_array(&notif.writer))
	528	goto error;
	529
99d223ad FD	530	/*
	531	* Send the notification (including the capture buffer) to the
	532	* sessiond.
	533	*/
	534	notification_send(&notif, event_notifier);
f125ded4 MD	535	return;
	536
	537	error:
	538	record_error(event_notifier);
99d223ad FD	539	return;
99d223ad FD	540	}