[lttng-tools.git] / src / bin / lttng-sessiond / ust-metadata.c

/*
 * ust-metadata.c
 *
 * LTTng-UST metadata generation
 *
 * Copyright (C) 2010-2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#define _GNU_SOURCE
#include <stdint.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <limits.h>
#include <unistd.h>
#include <inttypes.h>
#include <common/common.h>

#include "ust-registry.h"
#include "ust-clock.h"
#include "ust-app.h"

#ifndef max_t
#define max_t(type, a, b)	((type) ((a) > (b) ? (a) : (b)))
#endif

#define NR_CLOCK_OFFSET_SAMPLES		10

struct offset_sample {
	uint64_t offset;		/* correlation offset */
	uint64_t measure_delta;		/* lower is better */
};

static inline
int fls(unsigned int x)
{
	int r = 32;

	if (!x)
		return 0;
	if (!(x & 0xFFFF0000U)) {
		x <<= 16;
		r -= 16;
	}
	if (!(x & 0xFF000000U)) {
		x <<= 8;
		r -= 8;
	}
	if (!(x & 0xF0000000U)) {
		x <<= 4;
		r -= 4;
	}
	if (!(x & 0xC0000000U)) {
		x <<= 2;
		r -= 2;
	}
	if (!(x & 0x80000000U)) {
		x <<= 1;
		r -= 1;
	}
	return r;
}

static inline
int get_count_order(unsigned int count)
{
	int order;

	order = fls(count) - 1;
	if (count & (count - 1))
		order++;
	return order;
}

/*
 * Returns offset where to write in metadata array, or negative error value on error.
 */
static
ssize_t metadata_reserve(struct ust_registry_session *session, size_t len)
{
	size_t new_len = session->metadata_len + len;
	size_t new_alloc_len = new_len;
	size_t old_alloc_len = session->metadata_alloc_len;
	ssize_t ret;

	if (new_alloc_len > (UINT32_MAX >> 1))
		return -EINVAL;
	if ((old_alloc_len << 1) > (UINT32_MAX >> 1))
		return -EINVAL;

	if (new_alloc_len > old_alloc_len) {
		char *newptr;

		new_alloc_len =
			max_t(size_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
		newptr = realloc(session->metadata, new_alloc_len);
		if (!newptr)
			return -ENOMEM;
		session->metadata = newptr;
		/* We zero directly the memory from start of allocation. */
		memset(&session->metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len);
		session->metadata_alloc_len = new_alloc_len;
	}
	ret = session->metadata_len;
	session->metadata_len += len;
	return ret;
}

/*
 * We have exclusive access to our metadata buffer (protected by the
 * ust_lock), so we can do racy operations such as looking for
 * remaining space left in packet and write, since mutual exclusion
 * protects us from concurrent writes.
 */
static
int lttng_metadata_printf(struct ust_registry_session *session,
		const char *fmt, ...)
{
	char *str = NULL;
	size_t len;
	va_list ap;
	ssize_t offset;
	int ret;

	va_start(ap, fmt);
	ret = vasprintf(&str, fmt, ap);
	va_end(ap);
	if (ret < 0)
		return -ENOMEM;

	len = strlen(str);
	offset = metadata_reserve(session, len);
	if (offset < 0) {
		ret = offset;
		goto end;
	}
	memcpy(&session->metadata[offset], str, len);
	DBG3("Append to metadata: \"%s\"", str);
	ret = 0;

end:
	free(str);
	return ret;
}

static
int _lttng_field_statedump(struct ust_registry_session *session,
		const struct ustctl_field *field)
{
	int ret = 0;
	const char *bo_be = " byte_order = be;";
	const char *bo_le = " byte_order = le;";
	const char *bo_native = "";
	const char *bo_reverse;

	if (session->byte_order == BIG_ENDIAN)
		bo_reverse = bo_le;
	else
		bo_reverse = bo_be;

	switch (field->type.atype) {
	case ustctl_atype_integer:
		ret = lttng_metadata_printf(session,
			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
			field->type.u.basic.integer.size,
			field->type.u.basic.integer.alignment,
			field->type.u.basic.integer.signedness,
			(field->type.u.basic.integer.encoding == ustctl_encode_none)
				? "none"
				: (field->type.u.basic.integer.encoding == ustctl_encode_UTF8)
					? "UTF8"
					: "ASCII",
			field->type.u.basic.integer.base,
			field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
			field->name);
		break;
	case ustctl_atype_float:
		ret = lttng_metadata_printf(session,
			"		floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
			field->type.u.basic._float.exp_dig,
			field->type.u.basic._float.mant_dig,
			field->type.u.basic._float.alignment,
			field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
			field->name);
		break;
	case ustctl_atype_enum:
		return -EINVAL;
	case ustctl_atype_array:
	{
		const struct ustctl_basic_type *elem_type;

		elem_type = &field->type.u.array.elem_type;
		ret = lttng_metadata_printf(session,
			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
			elem_type->u.basic.integer.size,
			elem_type->u.basic.integer.alignment,
			elem_type->u.basic.integer.signedness,
			(elem_type->u.basic.integer.encoding == ustctl_encode_none)
				? "none"
				: (elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
					? "UTF8"
					: "ASCII",
			elem_type->u.basic.integer.base,
			elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
			field->name, field->type.u.array.length);
		break;
	}
	case ustctl_atype_sequence:
	{
		const struct ustctl_basic_type *elem_type;
		const struct ustctl_basic_type *length_type;

		elem_type = &field->type.u.sequence.elem_type;
		length_type = &field->type.u.sequence.length_type;
		ret = lttng_metadata_printf(session,
			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
			length_type->u.basic.integer.size,
			(unsigned int) length_type->u.basic.integer.alignment,
			length_type->u.basic.integer.signedness,
			(length_type->u.basic.integer.encoding == ustctl_encode_none)
				? "none"
				: ((length_type->u.basic.integer.encoding == ustctl_encode_UTF8)
					? "UTF8"
					: "ASCII"),
			length_type->u.basic.integer.base,
			length_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
			field->name);
		if (ret)
			return ret;

		ret = lttng_metadata_printf(session,
			"		integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
			elem_type->u.basic.integer.size,
			(unsigned int) elem_type->u.basic.integer.alignment,
			elem_type->u.basic.integer.signedness,
			(elem_type->u.basic.integer.encoding == ustctl_encode_none)
				? "none"
				: ((elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
					? "UTF8"
					: "ASCII"),
			elem_type->u.basic.integer.base,
			elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
			field->name,
			field->name);
		break;
	}

	case ustctl_atype_string:
		/* Default encoding is UTF8 */
		ret = lttng_metadata_printf(session,
			"		string%s _%s;\n",
			field->type.u.basic.string.encoding == ustctl_encode_ASCII ?
				" { encoding = ASCII; }" : "",
			field->name);
		break;
	default:
		return -EINVAL;
	}
	return ret;
}

static
int _lttng_context_metadata_statedump(struct ust_registry_session *session,
		size_t nr_ctx_fields,
		struct ustctl_field *ctx)
{
	int ret = 0;
	int i;

	if (!ctx)
		return 0;
	for (i = 0; i < nr_ctx_fields; i++) {
		const struct ustctl_field *field = &ctx[i];

		ret = _lttng_field_statedump(session, field);
		if (ret)
			return ret;
	}
	return ret;
}

static
int _lttng_fields_metadata_statedump(struct ust_registry_session *session,
		struct ust_registry_event *event)
{
	int ret = 0;
	int i;

	for (i = 0; i < event->nr_fields; i++) {
		const struct ustctl_field *field = &event->fields[i];

		ret = _lttng_field_statedump(session, field);
		if (ret)
			return ret;
	}
	return ret;
}

/*
 * Should be called with session registry mutex held.
 */
int ust_metadata_event_statedump(struct ust_registry_session *session,
		struct ust_registry_channel *chan,
		struct ust_registry_event *event)
{
	int ret = 0;

	/* Don't dump metadata events */
	if (chan->chan_id == -1U)
		return 0;

	ret = lttng_metadata_printf(session,
		"event {\n"
		"	name = \"%s\";\n"
		"	id = %u;\n"
		"	stream_id = %u;\n",
		event->name,
		event->id,
		chan->chan_id);
	if (ret)
		goto end;

	ret = lttng_metadata_printf(session,
		"	loglevel = %d;\n",
		event->loglevel);
	if (ret)
		goto end;

	if (event->model_emf_uri) {
		ret = lttng_metadata_printf(session,
			"	model.emf.uri = \"%s\";\n",
			event->model_emf_uri);
		if (ret)
			goto end;
	}

#if 0 /* context for events not supported */
	if (event->ctx) {
		ret = lttng_metadata_printf(session,
			"	context := struct {\n");
		if (ret)
			goto end;
	}
	ret = _lttng_context_metadata_statedump(session, event->ctx);
	if (ret)
		goto end;
	if (event->ctx) {
		ret = lttng_metadata_printf(session,
			"	};\n");
		if (ret)
			goto end;
	}
#endif
	ret = lttng_metadata_printf(session,
		"	fields := struct {\n"
		);
	if (ret)
		goto end;

	ret = _lttng_fields_metadata_statedump(session, event);
	if (ret)
		goto end;

	ret = lttng_metadata_printf(session,
		"	};\n"
		"};\n\n");
	if (ret)
		goto end;
	event->metadata_dumped = 1;

end:
	return ret;
}

/*
 * Should be called with session registry mutex held.
 */
int ust_metadata_channel_statedump(struct ust_registry_session *session,
		struct ust_registry_channel *chan)
{
	int ret = 0;

	/* Don't dump metadata events */
	if (chan->chan_id == -1U)
		return 0;

	if (!chan->header_type)
		return -EINVAL;

	ret = lttng_metadata_printf(session,
		"stream {\n"
		"	id = %u;\n"
		"	event.header := %s;\n"
		"	packet.context := struct packet_context;\n",
		chan->chan_id,
		chan->header_type == USTCTL_CHANNEL_HEADER_COMPACT ?
			"struct event_header_compact" :
			"struct event_header_large");
	if (ret)
		goto end;

	if (chan->ctx_fields) {
		ret = lttng_metadata_printf(session,
			"	event.context := struct {\n");
		if (ret)
			goto end;
	}
	ret = _lttng_context_metadata_statedump(session,
		chan->nr_ctx_fields,
		chan->ctx_fields);
	if (ret)
		goto end;
	if (chan->ctx_fields) {
		ret = lttng_metadata_printf(session,
			"	};\n");
		if (ret)
			goto end;
	}

	ret = lttng_metadata_printf(session,
		"};\n\n");
	/* Flag success of metadata dump. */
	chan->metadata_dumped = 1;

end:
	return ret;
}

static
int _lttng_stream_packet_context_declare(struct ust_registry_session *session)
{
	return lttng_metadata_printf(session,
		"struct packet_context {\n"
		"	uint64_clock_monotonic_t timestamp_begin;\n"
		"	uint64_clock_monotonic_t timestamp_end;\n"
		"	uint64_t content_size;\n"
		"	uint64_t packet_size;\n"
		"	unsigned long events_discarded;\n"
		"	uint32_t cpu_id;\n"
		"};\n\n"
		);
}

/*
 * Compact header:
 * id: range: 0 - 30.
 * id 31 is reserved to indicate an extended header.
 *
 * Large header:
 * id: range: 0 - 65534.
 * id 65535 is reserved to indicate an extended header.
 */
static
int _lttng_event_header_declare(struct ust_registry_session *session)
{
	return lttng_metadata_printf(session,
	"struct event_header_compact {\n"
	"	enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
	"	variant <id> {\n"
	"		struct {\n"
	"			uint27_clock_monotonic_t timestamp;\n"
	"		} compact;\n"
	"		struct {\n"
	"			uint32_t id;\n"
	"			uint64_clock_monotonic_t timestamp;\n"
	"		} extended;\n"
	"	} v;\n"
	"} align(%u);\n"
	"\n"
	"struct event_header_large {\n"
	"	enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
	"	variant <id> {\n"
	"		struct {\n"
	"			uint32_clock_monotonic_t timestamp;\n"
	"		} compact;\n"
	"		struct {\n"
	"			uint32_t id;\n"
	"			uint64_clock_monotonic_t timestamp;\n"
	"		} extended;\n"
	"	} v;\n"
	"} align(%u);\n\n",
	session->uint32_t_alignment,
	session->uint16_t_alignment
	);
}

static
int measure_single_clock_offset(struct offset_sample *sample)
{
	uint64_t offset, monotonic[2], measure_delta, realtime;
	struct timespec rts = { 0, 0 };
	int ret;

	monotonic[0] = trace_clock_read64();
	ret = clock_gettime(CLOCK_REALTIME, &rts);
	if (ret < 0) {
		return ret;
	}
	monotonic[1] = trace_clock_read64();
	measure_delta = monotonic[1] - monotonic[0];
	if (measure_delta > sample->measure_delta) {
		/*
		 * Discard value if it took longer to read than the best
		 * sample so far.
		 */
		return 0;
	}
	offset = (monotonic[0] + monotonic[1]) >> 1;
	realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
	realtime += rts.tv_nsec;
	offset = realtime - offset;
	sample->offset = offset;
	sample->measure_delta = measure_delta;
	return 0;
}

/*
 * Approximation of NTP time of day to clock monotonic correlation,
 * taken at start of trace. Keep the measurement that took the less time
 * to complete, thus removing imprecision caused by preemption.
 */
static
uint64_t measure_clock_offset(void)
{
	int i;
	struct offset_sample offset_best_sample = {
		.offset = 0,
		.measure_delta = UINT64_MAX,
	};

	for (i = 0; i < NR_CLOCK_OFFSET_SAMPLES; i++) {
		if (measure_single_clock_offset(&offset_best_sample)) {
			return 0;
		}
	}
	return offset_best_sample.offset;
}

/*
 * Should be called with session registry mutex held.
 */
int ust_metadata_session_statedump(struct ust_registry_session *session,
		struct ust_app *app,
		uint32_t major,
		uint32_t minor)
{
	unsigned char *uuid_c;
	char uuid_s[UUID_STR_LEN],
		clock_uuid_s[UUID_STR_LEN];
	int ret = 0;
	char hostname[HOST_NAME_MAX];

	assert(session);

	uuid_c = session->uuid;

	snprintf(uuid_s, sizeof(uuid_s),
		"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
		uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
		uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
		uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
		uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);

	ret = lttng_metadata_printf(session,
		"typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
		"typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
		"typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
		"typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
		"typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
		"typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
		"typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
		"\n"
		"trace {\n"
		"	major = %u;\n"
		"	minor = %u;\n"
		"	uuid = \"%s\";\n"
		"	byte_order = %s;\n"
		"	packet.header := struct {\n"
		"		uint32_t magic;\n"
		"		uint8_t  uuid[16];\n"
		"		uint32_t stream_id;\n"
		"	};\n"
		"};\n\n",
		session->uint8_t_alignment,
		session->uint16_t_alignment,
		session->uint32_t_alignment,
		session->uint64_t_alignment,
		session->bits_per_long,
		session->long_alignment,
		CTF_SPEC_MAJOR,
		CTF_SPEC_MINOR,
		uuid_s,
		session->byte_order == BIG_ENDIAN ? "be" : "le"
		);
	if (ret)
		goto end;

	/* ignore error, just use empty string if error. */
	hostname[0] = '\0';
	ret = gethostname(hostname, sizeof(hostname));
	if (ret && errno == ENAMETOOLONG)
		hostname[HOST_NAME_MAX - 1] = '\0';
	ret = lttng_metadata_printf(session,
		"env {\n"
		"	hostname = \"%s\";\n"
		"	domain = \"ust\";\n"
		"	tracer_name = \"lttng-ust\";\n"
		"	tracer_major = %u;\n"
		"	tracer_minor = %u;\n",
		hostname,
		major,
		minor
		);
	if (ret)
		goto end;

	/*
	 * If per-application registry, we can output extra information
	 * about the application.
	 */
	if (app) {
		ret = lttng_metadata_printf(session,
			"	tracer_patchlevel = %u;\n"
			"	vpid = %d;\n"
			"	procname = \"%s\";\n",
			app->version.patchlevel,
			(int) app->pid,
			app->name
			);
		if (ret)
			goto end;
	}

	ret = lttng_metadata_printf(session,
		"};\n\n"
		);
	if (ret)
		goto end;


	ret = lttng_metadata_printf(session,
		"clock {\n"
		"	name = %s;\n",
		"monotonic"
		);
	if (ret)
		goto end;

	if (!trace_clock_uuid(clock_uuid_s)) {
		ret = lttng_metadata_printf(session,
			"	uuid = \"%s\";\n",
			clock_uuid_s
			);
		if (ret)
			goto end;
	}

	ret = lttng_metadata_printf(session,
		"	description = \"Monotonic Clock\";\n"
		"	freq = %" PRIu64 "; /* Frequency, in Hz */\n"
		"	/* clock value offset from Epoch is: offset * (1/freq) */\n"
		"	offset = %" PRIu64 ";\n"
		"};\n\n",
		trace_clock_freq(),
		measure_clock_offset()
		);
	if (ret)
		goto end;

	ret = lttng_metadata_printf(session,
		"typealias integer {\n"
		"	size = 27; align = 1; signed = false;\n"
		"	map = clock.monotonic.value;\n"
		"} := uint27_clock_monotonic_t;\n"
		"\n"
		"typealias integer {\n"
		"	size = 32; align = %u; signed = false;\n"
		"	map = clock.monotonic.value;\n"
		"} := uint32_clock_monotonic_t;\n"
		"\n"
		"typealias integer {\n"
		"	size = 64; align = %u; signed = false;\n"
		"	map = clock.monotonic.value;\n"
		"} := uint64_clock_monotonic_t;\n\n",
		session->uint32_t_alignment,
		session->uint64_t_alignment
		);
	if (ret)
		goto end;

	ret = _lttng_stream_packet_context_declare(session);
	if (ret)
		goto end;

	ret = _lttng_event_header_declare(session);
	if (ret)
		goto end;

end:
	return ret;
}
Commit	Line	Data
d0b96690 DG	1	/*
	2	* ust-metadata.c
	3	*
	4	* LTTng-UST metadata generation
	5	*
	6	* Copyright (C) 2010-2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License, version 2 only,
	10	* as published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License along
	18	* with this program; if not, write to the Free Software Foundation, Inc.,
	19	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	20	*/
	21
	22	#define _GNU_SOURCE
	23	#include <stdint.h>
	24	#include <string.h>
	25	#include <stdarg.h>
	26	#include <stdio.h>
	27	#include <limits.h>
	28	#include <unistd.h>
	29	#include <inttypes.h>
	30	#include <common/common.h>
	31
	32	#include "ust-registry.h"
	33	#include "ust-clock.h"
	34	#include "ust-app.h"
	35
	36	#ifndef max_t
	37	#define max_t(type, a, b) ((type) ((a) > (b) ? (a) : (b)))
	38	#endif
	39
9fa0d1c8 MD	40	#define NR_CLOCK_OFFSET_SAMPLES 10
	41
	42	struct offset_sample {
	43	uint64_t offset; /* correlation offset */
	44	uint64_t measure_delta; /* lower is better */
	45	};
	46
d0b96690 DG	47	static inline
	48	int fls(unsigned int x)
	49	{
	50	int r = 32;
	51
	52	if (!x)
	53	return 0;
	54	if (!(x & 0xFFFF0000U)) {
	55	x <<= 16;
	56	r -= 16;
	57	}
	58	if (!(x & 0xFF000000U)) {
	59	x <<= 8;
	60	r -= 8;
	61	}
	62	if (!(x & 0xF0000000U)) {
	63	x <<= 4;
	64	r -= 4;
	65	}
	66	if (!(x & 0xC0000000U)) {
	67	x <<= 2;
	68	r -= 2;
	69	}
	70	if (!(x & 0x80000000U)) {
	71	x <<= 1;
	72	r -= 1;
	73	}
	74	return r;
	75	}
	76
	77	static inline
	78	int get_count_order(unsigned int count)
	79	{
	80	int order;
	81
	82	order = fls(count) - 1;
	83	if (count & (count - 1))
	84	order++;
	85	return order;
	86	}
	87
	88	/*
	89	* Returns offset where to write in metadata array, or negative error value on error.
	90	*/
	91	static
	92	ssize_t metadata_reserve(struct ust_registry_session *session, size_t len)
	93	{
	94	size_t new_len = session->metadata_len + len;
	95	size_t new_alloc_len = new_len;
	96	size_t old_alloc_len = session->metadata_alloc_len;
	97	ssize_t ret;
	98
	99	if (new_alloc_len > (UINT32_MAX >> 1))
	100	return -EINVAL;
	101	if ((old_alloc_len << 1) > (UINT32_MAX >> 1))
	102	return -EINVAL;
	103
	104	if (new_alloc_len > old_alloc_len) {
	105	char *newptr;
	106
	107	new_alloc_len =
	108	max_t(size_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
	109	newptr = realloc(session->metadata, new_alloc_len);
	110	if (!newptr)
111	return -ENOMEM;
112	session->metadata = newptr;
113	/* We zero directly the memory from start of allocation. */
114	memset(&session->metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len);
115	session->metadata_alloc_len = new_alloc_len;
116	}
117	ret = session->metadata_len;
118	session->metadata_len += len;
119	return ret;
120	}
121
122	/*
123	* We have exclusive access to our metadata buffer (protected by the
124	* ust_lock), so we can do racy operations such as looking for
125	* remaining space left in packet and write, since mutual exclusion
126	* protects us from concurrent writes.
127	*/
128	static
129	int lttng_metadata_printf(struct ust_registry_session *session,
130	const char *fmt, ...)
131	{
132	char *str = NULL;
133	size_t len;
134	va_list ap;
135	ssize_t offset;
136	int ret;
137
138	va_start(ap, fmt);
139	ret = vasprintf(&str, fmt, ap);
140	va_end(ap);
141	if (ret < 0)
142	return -ENOMEM;
143
144	len = strlen(str);
145	offset = metadata_reserve(session, len);
146	if (offset < 0) {
147	ret = offset;
148	goto end;
149	}
150	memcpy(&session->metadata[offset], str, len);
151	DBG3("Append to metadata: \"%s\"", str);
152	ret = 0;
153
154	end:
155	free(str);
156	return ret;
157	}
158
159	static
160	int _lttng_field_statedump(struct ust_registry_session *session,
161	const struct ustctl_field *field)
162	{
163	int ret = 0;
164	const char *bo_be = " byte_order = be;";
165	const char *bo_le = " byte_order = le;";
166	const char *bo_native = "";
167	const char *bo_reverse;
168
169	if (session->byte_order == BIG_ENDIAN)
170	bo_reverse = bo_le;
171	else
172	bo_reverse = bo_be;
173
174	switch (field->type.atype) {
175	case ustctl_atype_integer:
176	ret = lttng_metadata_printf(session,
177	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
178	field->type.u.basic.integer.size,
179	field->type.u.basic.integer.alignment,
180	field->type.u.basic.integer.signedness,
181	(field->type.u.basic.integer.encoding == ustctl_encode_none)
182	? "none"
183	: (field->type.u.basic.integer.encoding == ustctl_encode_UTF8)
184	? "UTF8"
185	: "ASCII",
186	field->type.u.basic.integer.base,
187	field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
188	field->name);
189	break;
190	case ustctl_atype_float:
191	ret = lttng_metadata_printf(session,
192	" floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
193	field->type.u.basic._float.exp_dig,
194	field->type.u.basic._float.mant_dig,
195	field->type.u.basic._float.alignment,
196	field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
197	field->name);
198	break;
199	case ustctl_atype_enum:
200	return -EINVAL;
201	case ustctl_atype_array:
202	{
203	const struct ustctl_basic_type *elem_type;
204
205	elem_type = &field->type.u.array.elem_type;
206	ret = lttng_metadata_printf(session,
207	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
208	elem_type->u.basic.integer.size,
209	elem_type->u.basic.integer.alignment,
210	elem_type->u.basic.integer.signedness,
211	(elem_type->u.basic.integer.encoding == ustctl_encode_none)
212	? "none"
213	: (elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
214	? "UTF8"
215	: "ASCII",
216	elem_type->u.basic.integer.base,
217	elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
218	field->name, field->type.u.array.length);
219	break;
220	}
221	case ustctl_atype_sequence:
222	{
223	const struct ustctl_basic_type *elem_type;
224	const struct ustctl_basic_type *length_type;
225
226	elem_type = &field->type.u.sequence.elem_type;
227	length_type = &field->type.u.sequence.length_type;
228	ret = lttng_metadata_printf(session,
229	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
230	length_type->u.basic.integer.size,
231	(unsigned int) length_type->u.basic.integer.alignment,
232	length_type->u.basic.integer.signedness,
233	(length_type->u.basic.integer.encoding == ustctl_encode_none)
234	? "none"
235	: ((length_type->u.basic.integer.encoding == ustctl_encode_UTF8)
236	? "UTF8"
237	: "ASCII"),
238	length_type->u.basic.integer.base,
239	length_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
240	field->name);
241	if (ret)
242	return ret;
243
244	ret = lttng_metadata_printf(session,
245	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
246	elem_type->u.basic.integer.size,
247	(unsigned int) elem_type->u.basic.integer.alignment,
248	elem_type->u.basic.integer.signedness,
249	(elem_type->u.basic.integer.encoding == ustctl_encode_none)
250	? "none"
251	: ((elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
252	? "UTF8"
253	: "ASCII"),
254	elem_type->u.basic.integer.base,
255	elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
256	field->name,
257	field->name);
258	break;
259	}
260
261	case ustctl_atype_string:
262	/* Default encoding is UTF8 */
263	ret = lttng_metadata_printf(session,
264	" string%s _%s;\n",
265	field->type.u.basic.string.encoding == ustctl_encode_ASCII ?
266	" { encoding = ASCII; }" : "",
267	field->name);
268	break;
269	default:
270	return -EINVAL;
271	}
272	return ret;
273	}
274
275	static
276	int _lttng_context_metadata_statedump(struct ust_registry_session *session,
277	size_t nr_ctx_fields,
278	struct ustctl_field *ctx)
279	{
280	int ret = 0;
281	int i;
282
283	if (!ctx)
284	return 0;
285	for (i = 0; i < nr_ctx_fields; i++) {
286	const struct ustctl_field *field = &ctx[i];
287
288	ret = _lttng_field_statedump(session, field);
289	if (ret)
290	return ret;
291	}
292	return ret;
293	}
294
295	static
296	int _lttng_fields_metadata_statedump(struct ust_registry_session *session,
297	struct ust_registry_event *event)
298	{
299	int ret = 0;
300	int i;
301
302	for (i = 0; i < event->nr_fields; i++) {
303	const struct ustctl_field *field = &event->fields[i];
304
305	ret = _lttng_field_statedump(session, field);
306	if (ret)
307	return ret;
308	}
309	return ret;
310	}
311
312	/*
313	* Should be called with session registry mutex held.
314	*/
315	int ust_metadata_event_statedump(struct ust_registry_session *session,
316	struct ust_registry_channel *chan,
317	struct ust_registry_event *event)
318	{
319	int ret = 0;
320
321	/* Don't dump metadata events */
322	if (chan->chan_id == -1U)
323	return 0;
324
325	ret = lttng_metadata_printf(session,
326	"event {\n"
327	" name = \"%s\";\n"
328	" id = %u;\n"
329	" stream_id = %u;\n",
330	event->name,
331	event->id,
332	chan->chan_id);
333	if (ret)
334	goto end;
335
336	ret = lttng_metadata_printf(session,
337	" loglevel = %d;\n",
338	event->loglevel);
339	if (ret)
340	goto end;
341
342	if (event->model_emf_uri) {
343	ret = lttng_metadata_printf(session,
344	" model.emf.uri = \"%s\";\n",
345	event->model_emf_uri);
346	if (ret)
347	goto end;
348	}
349
350	#if 0 /* context for events not supported */
351	if (event->ctx) {
352	ret = lttng_metadata_printf(session,
353	" context := struct {\n");
354	if (ret)
355	goto end;
356	}
357	ret = _lttng_context_metadata_statedump(session, event->ctx);
358	if (ret)
359	goto end;
360	if (event->ctx) {
361	ret = lttng_metadata_printf(session,
362	" };\n");
363	if (ret)
364	goto end;
365	}
366	#endif
367	ret = lttng_metadata_printf(session,
368	" fields := struct {\n"
369	);
370	if (ret)
371	goto end;
372
373	ret = _lttng_fields_metadata_statedump(session, event);
374	if (ret)
375	goto end;
376
377	ret = lttng_metadata_printf(session,
378	" };\n"
379	"};\n\n");
380	if (ret)
381	goto end;
7972aab2	382	event->metadata_dumped = 1;
d0b96690 DG	383
	384	end:
	385	return ret;
	386	}
	387
	388	/*
	389	* Should be called with session registry mutex held.
	390	*/
	391	int ust_metadata_channel_statedump(struct ust_registry_session *session,
	392	struct ust_registry_channel *chan)
	393	{
	394	int ret = 0;
	395
	396	/* Don't dump metadata events */
	397	if (chan->chan_id == -1U)
	398	return 0;
	399
	400	if (!chan->header_type)
	401	return -EINVAL;
	402
	403	ret = lttng_metadata_printf(session,
	404	"stream {\n"
	405	" id = %u;\n"
	406	" event.header := %s;\n"
	407	" packet.context := struct packet_context;\n",
	408	chan->chan_id,
	409	chan->header_type == USTCTL_CHANNEL_HEADER_COMPACT ?
	410	"struct event_header_compact" :
	411	"struct event_header_large");
	412	if (ret)
	413	goto end;
	414
	415	if (chan->ctx_fields) {
	416	ret = lttng_metadata_printf(session,
	417	" event.context := struct {\n");
	418	if (ret)
	419	goto end;
	420	}
	421	ret = _lttng_context_metadata_statedump(session,
	422	chan->nr_ctx_fields,
	423	chan->ctx_fields);
	424	if (ret)
	425	goto end;
	426	if (chan->ctx_fields) {
	427	ret = lttng_metadata_printf(session,
	428	" };\n");
	429	if (ret)
	430	goto end;
	431	}
	432
	433	ret = lttng_metadata_printf(session,
	434	"};\n\n");
7972aab2 DG	435	/* Flag success of metadata dump. */
7972aab2 DG	436	chan->metadata_dumped = 1;
d0b96690 DG	437
	438	end:
	439	return ret;
	440	}
	441
	442	static
	443	int _lttng_stream_packet_context_declare(struct ust_registry_session *session)
	444	{
	445	return lttng_metadata_printf(session,
	446	"struct packet_context {\n"
	447	" uint64_clock_monotonic_t timestamp_begin;\n"
	448	" uint64_clock_monotonic_t timestamp_end;\n"
	449	" uint64_t content_size;\n"
	450	" uint64_t packet_size;\n"
	451	" unsigned long events_discarded;\n"
	452	" uint32_t cpu_id;\n"
	453	"};\n\n"
	454	);
	455	}
	456
	457	/*
	458	* Compact header:
	459	* id: range: 0 - 30.
	460	* id 31 is reserved to indicate an extended header.
	461	*
	462	* Large header:
	463	* id: range: 0 - 65534.
	464	* id 65535 is reserved to indicate an extended header.
	465	*/
	466	static
	467	int _lttng_event_header_declare(struct ust_registry_session *session)
	468	{
	469	return lttng_metadata_printf(session,
	470	"struct event_header_compact {\n"
	471	" enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
	472	" variant <id> {\n"
	473	" struct {\n"
	474	" uint27_clock_monotonic_t timestamp;\n"
	475	" } compact;\n"
	476	" struct {\n"
	477	" uint32_t id;\n"
	478	" uint64_clock_monotonic_t timestamp;\n"
	479	" } extended;\n"
	480	" } v;\n"
	481	"} align(%u);\n"
	482	"\n"
	483	"struct event_header_large {\n"
	484	" enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
	485	" variant <id> {\n"
	486	" struct {\n"
	487	" uint32_clock_monotonic_t timestamp;\n"
	488	" } compact;\n"
	489	" struct {\n"
	490	" uint32_t id;\n"
	491	" uint64_clock_monotonic_t timestamp;\n"
	492	" } extended;\n"
	493	" } v;\n"
	494	"} align(%u);\n\n",
	495	session->uint32_t_alignment,
	496	session->uint16_t_alignment
	497	);
	498	}
	499
d0b96690	500	static
9fa0d1c8	501	int measure_single_clock_offset(struct offset_sample *sample)
d0b96690	502	{
9fa0d1c8	503	uint64_t offset, monotonic[2], measure_delta, realtime;
d0b96690 DG	504	struct timespec rts = { 0, 0 };
	505	int ret;
	506
	507	monotonic[0] = trace_clock_read64();
	508	ret = clock_gettime(CLOCK_REALTIME, &rts);
9fa0d1c8 MD	509	if (ret < 0) {
	510	return ret;
	511	}
d0b96690	512	monotonic[1] = trace_clock_read64();
9fa0d1c8 MD	513	measure_delta = monotonic[1] - monotonic[0];
	514	if (measure_delta > sample->measure_delta) {
	515	/*
	516	* Discard value if it took longer to read than the best
	517	* sample so far.
	518	*/
	519	return 0;
	520	}
d0b96690 DG	521	offset = (monotonic[0] + monotonic[1]) >> 1;
	522	realtime = (uint64_t) rts.tv_sec * 1000000000ULL;
	523	realtime += rts.tv_nsec;
	524	offset = realtime - offset;
9fa0d1c8 MD	525	sample->offset = offset;
	526	sample->measure_delta = measure_delta;
	527	return 0;
d0b96690 DG	528	}
d0b96690 DG	529
9fa0d1c8 MD	530	/*
	531	* Approximation of NTP time of day to clock monotonic correlation,
	532	* taken at start of trace. Keep the measurement that took the less time
	533	* to complete, thus removing imprecision caused by preemption.
	534	*/
	535	static
	536	uint64_t measure_clock_offset(void)
	537	{
	538	int i;
	539	struct offset_sample offset_best_sample = {
	540	.offset = 0,
	541	.measure_delta = UINT64_MAX,
	542	};
	543
	544	for (i = 0; i < NR_CLOCK_OFFSET_SAMPLES; i++) {
	545	if (measure_single_clock_offset(&offset_best_sample)) {
	546	return 0;
	547	}
	548	}
	549	return offset_best_sample.offset;
	550	}
d0b96690 DG	551
	552	/*
	553	* Should be called with session registry mutex held.
	554	*/
	555	int ust_metadata_session_statedump(struct ust_registry_session *session,
af6142cf MD	556	struct ust_app *app,
	557	uint32_t major,
	558	uint32_t minor)
d0b96690 DG	559	{
	560	unsigned char *uuid_c;
	561	char uuid_s[UUID_STR_LEN],
	562	clock_uuid_s[UUID_STR_LEN];
	563	int ret = 0;
	564	char hostname[HOST_NAME_MAX];
	565
7972aab2	566	assert(session);
7972aab2	567
d0b96690 DG	568	uuid_c = session->uuid;
	569
	570	snprintf(uuid_s, sizeof(uuid_s),
	571	"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
	572	uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
	573	uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
	574	uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
	575	uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
	576
	577	ret = lttng_metadata_printf(session,
	578	"typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
	579	"typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
	580	"typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
	581	"typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
	582	"typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
	583	"typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
	584	"typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
	585	"\n"
	586	"trace {\n"
	587	" major = %u;\n"
	588	" minor = %u;\n"
	589	" uuid = \"%s\";\n"
	590	" byte_order = %s;\n"
	591	" packet.header := struct {\n"
	592	" uint32_t magic;\n"
	593	" uint8_t uuid[16];\n"
	594	" uint32_t stream_id;\n"
	595	" };\n"
	596	"};\n\n",
	597	session->uint8_t_alignment,
	598	session->uint16_t_alignment,
	599	session->uint32_t_alignment,
	600	session->uint64_t_alignment,
	601	session->bits_per_long,
	602	session->long_alignment,
	603	CTF_SPEC_MAJOR,
	604	CTF_SPEC_MINOR,
	605	uuid_s,
	606	session->byte_order == BIG_ENDIAN ? "be" : "le"
	607	);
	608	if (ret)
	609	goto end;
	610
	611	/* ignore error, just use empty string if error. */
	612	hostname[0] = '\0';
	613	ret = gethostname(hostname, sizeof(hostname));
	614	if (ret && errno == ENAMETOOLONG)
	615	hostname[HOST_NAME_MAX - 1] = '\0';
	616	ret = lttng_metadata_printf(session,
	617	"env {\n"
	618	" hostname = \"%s\";\n"
	619	" domain = \"ust\";\n"
	620	" tracer_name = \"lttng-ust\";\n"
	621	" tracer_major = %u;\n"
af6142cf	622	" tracer_minor = %u;\n",
d0b96690	623	hostname,
af6142cf MD	624	major,
af6142cf MD	625	minor
d0b96690 DG	626	);
	627	if (ret)
	628	goto end;
	629
	630	/*
	631	* If per-application registry, we can output extra information
	632	* about the application.
	633	*/
	634	if (app) {
	635	ret = lttng_metadata_printf(session,
af6142cf	636	" tracer_patchlevel = %u;\n"
d0b96690	637	" vpid = %d;\n"
d88aee68	638	" procname = \"%s\";\n",
af6142cf	639	app->version.patchlevel,
d0b96690 DG	640	(int) app->pid,
	641	app->name
	642	);
	643	if (ret)
	644	goto end;
	645	}
	646
	647	ret = lttng_metadata_printf(session,
	648	"};\n\n"
	649	);
	650	if (ret)
	651	goto end;
	652
	653
	654	ret = lttng_metadata_printf(session,
	655	"clock {\n"
	656	" name = %s;\n",
	657	"monotonic"
	658	);
	659	if (ret)
	660	goto end;
	661
	662	if (!trace_clock_uuid(clock_uuid_s)) {
	663	ret = lttng_metadata_printf(session,
	664	" uuid = \"%s\";\n",
	665	clock_uuid_s
	666	);
	667	if (ret)
	668	goto end;
	669	}
	670
	671	ret = lttng_metadata_printf(session,
	672	" description = \"Monotonic Clock\";\n"
	673	" freq = %" PRIu64 "; /* Frequency, in Hz */\n"
	674	" /* clock value offset from Epoch is: offset * (1/freq) */\n"
	675	" offset = %" PRIu64 ";\n"
	676	"};\n\n",
	677	trace_clock_freq(),
	678	measure_clock_offset()
	679	);
	680	if (ret)
	681	goto end;
	682
	683	ret = lttng_metadata_printf(session,
	684	"typealias integer {\n"
	685	" size = 27; align = 1; signed = false;\n"
	686	" map = clock.monotonic.value;\n"
	687	"} := uint27_clock_monotonic_t;\n"
	688	"\n"
	689	"typealias integer {\n"
	690	" size = 32; align = %u; signed = false;\n"
	691	" map = clock.monotonic.value;\n"
	692	"} := uint32_clock_monotonic_t;\n"
	693	"\n"
	694	"typealias integer {\n"
	695	" size = 64; align = %u; signed = false;\n"
	696	" map = clock.monotonic.value;\n"
	697	"} := uint64_clock_monotonic_t;\n\n",
	698	session->uint32_t_alignment,
	699	session->uint64_t_alignment
	700	);
	701	if (ret)
	702	goto end;
	703
704	ret = _lttng_stream_packet_context_declare(session);
705	if (ret)
706	goto end;
707
708	ret = _lttng_event_header_declare(session);
709	if (ret)
710	goto end;
711
712	end:
713	return ret;
714	}