[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
#define _LGPL_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 NSEC_PER_SEC			1000000000ULL
#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;
}

static
int metadata_file_append(struct ust_registry_session *session,
		const char *str, size_t len)
{
	ssize_t written;

	if (session->metadata_fd < 0) {
		return 0;
	}
	/* Write to metadata file */
	written = lttng_write(session->metadata_fd, str, len);
	if (written != len) {
		return -1;
	}
	return 0;
}

/*
 * 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);
	ret = metadata_file_append(session, str, len);
	if (ret) {
		PERROR("Error appending to metadata file");
		goto end;
	}
	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;
	uint64_t tcf = trace_clock_freq();
	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 * tcf;
	if (tcf == NSEC_PER_SEC) {
		realtime += rts.tv_nsec;
	} else {
		realtime += (uint64_t) rts.tv_nsec * tcf / NSEC_PER_SEC;
	}
	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]);

	/* For crash ABI */
	ret = lttng_metadata_printf(session,
		"/* CTF %u.%u */\n\n",
		CTF_SPEC_MAJOR,
		CTF_SPEC_MINOR);
	if (ret) {
		goto end;
	}

	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",
		trace_clock_name()
		);
	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 = \"%s\";\n"
		"	freq = %" PRIu64 "; /* Frequency, in Hz */\n"
		"	/* clock value offset from Epoch is: offset * (1/freq) */\n"
		"	offset = %" PRIu64 ";\n"
		"};\n\n",
		trace_clock_description(),
		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.%s.value;\n"
		"} := uint27_clock_monotonic_t;\n"
		"\n"
		"typealias integer {\n"
		"	size = 32; align = %u; signed = false;\n"
		"	map = clock.%s.value;\n"
		"} := uint32_clock_monotonic_t;\n"
		"\n"
		"typealias integer {\n"
		"	size = 64; align = %u; signed = false;\n"
		"	map = clock.%s.value;\n"
		"} := uint64_clock_monotonic_t;\n\n",
		trace_clock_name(),
		session->uint32_t_alignment,
		trace_clock_name(),
		session->uint64_t_alignment,
		trace_clock_name()
		);
	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
6c1c0768	23	#define _LGPL_SOURCE
d0b96690 DG	24	#include <stdint.h>
	25	#include <string.h>
	26	#include <stdarg.h>
	27	#include <stdio.h>
	28	#include <limits.h>
	29	#include <unistd.h>
	30	#include <inttypes.h>
	31	#include <common/common.h>
	32
	33	#include "ust-registry.h"
	34	#include "ust-clock.h"
	35	#include "ust-app.h"
	36
	37	#ifndef max_t
	38	#define max_t(type, a, b) ((type) ((a) > (b) ? (a) : (b)))
	39	#endif
	40
6e1b0543	41	#define NSEC_PER_SEC 1000000000ULL
8c645bb0 MD	42	#define NR_CLOCK_OFFSET_SAMPLES 10
	43
	44	struct offset_sample {
	45	uint64_t offset; /* correlation offset */
	46	uint64_t measure_delta; /* lower is better */
	47	};
	48
d0b96690 DG	49	static inline
	50	int fls(unsigned int x)
	51	{
	52	int r = 32;
	53
	54	if (!x)
	55	return 0;
	56	if (!(x & 0xFFFF0000U)) {
	57	x <<= 16;
	58	r -= 16;
	59	}
	60	if (!(x & 0xFF000000U)) {
	61	x <<= 8;
	62	r -= 8;
	63	}
	64	if (!(x & 0xF0000000U)) {
	65	x <<= 4;
	66	r -= 4;
	67	}
	68	if (!(x & 0xC0000000U)) {
	69	x <<= 2;
	70	r -= 2;
	71	}
	72	if (!(x & 0x80000000U)) {
	73	x <<= 1;
	74	r -= 1;
	75	}
	76	return r;
	77	}
	78
	79	static inline
	80	int get_count_order(unsigned int count)
	81	{
	82	int order;
	83
	84	order = fls(count) - 1;
	85	if (count & (count - 1))
	86	order++;
	87	return order;
	88	}
	89
	90	/*
	91	* Returns offset where to write in metadata array, or negative error value on error.
	92	*/
	93	static
	94	ssize_t metadata_reserve(struct ust_registry_session *session, size_t len)
	95	{
	96	size_t new_len = session->metadata_len + len;
	97	size_t new_alloc_len = new_len;
	98	size_t old_alloc_len = session->metadata_alloc_len;
	99	ssize_t ret;
	100
	101	if (new_alloc_len > (UINT32_MAX >> 1))
	102	return -EINVAL;
	103	if ((old_alloc_len << 1) > (UINT32_MAX >> 1))
	104	return -EINVAL;
	105
	106	if (new_alloc_len > old_alloc_len) {
	107	char *newptr;
	108
	109	new_alloc_len =
	110	max_t(size_t, 1U << get_count_order(new_alloc_len), old_alloc_len << 1);
	111	newptr = realloc(session->metadata, new_alloc_len);
	112	if (!newptr)
113	return -ENOMEM;
114	session->metadata = newptr;
115	/* We zero directly the memory from start of allocation. */
116	memset(&session->metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len);
117	session->metadata_alloc_len = new_alloc_len;
118	}
119	ret = session->metadata_len;
120	session->metadata_len += len;
121	return ret;
122	}
123
d7ba1388 MD	124	static
	125	int metadata_file_append(struct ust_registry_session *session,
	126	const char *str, size_t len)
	127	{
	128	ssize_t written;
	129
	130	if (session->metadata_fd < 0) {
	131	return 0;
	132	}
	133	/* Write to metadata file */
	134	written = lttng_write(session->metadata_fd, str, len);
	135	if (written != len) {
	136	return -1;
	137	}
	138	return 0;
	139	}
	140
d0b96690 DG	141	/*
	142	* We have exclusive access to our metadata buffer (protected by the
	143	* ust_lock), so we can do racy operations such as looking for
	144	* remaining space left in packet and write, since mutual exclusion
	145	* protects us from concurrent writes.
	146	*/
	147	static
	148	int lttng_metadata_printf(struct ust_registry_session *session,
	149	const char *fmt, ...)
	150	{
	151	char *str = NULL;
	152	size_t len;
	153	va_list ap;
	154	ssize_t offset;
	155	int ret;
	156
	157	va_start(ap, fmt);
	158	ret = vasprintf(&str, fmt, ap);
	159	va_end(ap);
	160	if (ret < 0)
	161	return -ENOMEM;
	162
	163	len = strlen(str);
	164	offset = metadata_reserve(session, len);
	165	if (offset < 0) {
	166	ret = offset;
	167	goto end;
	168	}
	169	memcpy(&session->metadata[offset], str, len);
d7ba1388 MD	170	ret = metadata_file_append(session, str, len);
	171	if (ret) {
	172	PERROR("Error appending to metadata file");
	173	goto end;
	174	}
d0b96690 DG	175	DBG3("Append to metadata: \"%s\"", str);
	176	ret = 0;
	177
	178	end:
	179	free(str);
	180	return ret;
	181	}
	182
	183	static
	184	int _lttng_field_statedump(struct ust_registry_session *session,
	185	const struct ustctl_field *field)
	186	{
	187	int ret = 0;
	188	const char *bo_be = " byte_order = be;";
	189	const char *bo_le = " byte_order = le;";
	190	const char *bo_native = "";
	191	const char *bo_reverse;
	192
	193	if (session->byte_order == BIG_ENDIAN)
	194	bo_reverse = bo_le;
	195	else
	196	bo_reverse = bo_be;
	197
	198	switch (field->type.atype) {
	199	case ustctl_atype_integer:
	200	ret = lttng_metadata_printf(session,
	201	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s;\n",
	202	field->type.u.basic.integer.size,
	203	field->type.u.basic.integer.alignment,
	204	field->type.u.basic.integer.signedness,
	205	(field->type.u.basic.integer.encoding == ustctl_encode_none)
	206	? "none"
	207	: (field->type.u.basic.integer.encoding == ustctl_encode_UTF8)
	208	? "UTF8"
	209	: "ASCII",
	210	field->type.u.basic.integer.base,
	211	field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
	212	field->name);
	213	break;
	214	case ustctl_atype_float:
	215	ret = lttng_metadata_printf(session,
	216	" floating_point { exp_dig = %u; mant_dig = %u; align = %u;%s } _%s;\n",
	217	field->type.u.basic._float.exp_dig,
	218	field->type.u.basic._float.mant_dig,
	219	field->type.u.basic._float.alignment,
	220	field->type.u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
	221	field->name);
	222	break;
	223	case ustctl_atype_enum:
	224	return -EINVAL;
	225	case ustctl_atype_array:
	226	{
	227	const struct ustctl_basic_type *elem_type;
	228
	229	elem_type = &field->type.u.array.elem_type;
	230	ret = lttng_metadata_printf(session,
	231	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
	232	elem_type->u.basic.integer.size,
	233	elem_type->u.basic.integer.alignment,
	234	elem_type->u.basic.integer.signedness,
	235	(elem_type->u.basic.integer.encoding == ustctl_encode_none)
	236	? "none"
	237	: (elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
	238	? "UTF8"
239	: "ASCII",
240	elem_type->u.basic.integer.base,
241	elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
242	field->name, field->type.u.array.length);
243	break;
244	}
245	case ustctl_atype_sequence:
246	{
247	const struct ustctl_basic_type *elem_type;
248	const struct ustctl_basic_type *length_type;
249
250	elem_type = &field->type.u.sequence.elem_type;
251	length_type = &field->type.u.sequence.length_type;
252	ret = lttng_metadata_printf(session,
253	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } __%s_length;\n",
254	length_type->u.basic.integer.size,
255	(unsigned int) length_type->u.basic.integer.alignment,
256	length_type->u.basic.integer.signedness,
257	(length_type->u.basic.integer.encoding == ustctl_encode_none)
258	? "none"
259	: ((length_type->u.basic.integer.encoding == ustctl_encode_UTF8)
260	? "UTF8"
261	: "ASCII"),
262	length_type->u.basic.integer.base,
263	length_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
264	field->name);
265	if (ret)
266	return ret;
267
268	ret = lttng_metadata_printf(session,
269	" integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
270	elem_type->u.basic.integer.size,
271	(unsigned int) elem_type->u.basic.integer.alignment,
272	elem_type->u.basic.integer.signedness,
273	(elem_type->u.basic.integer.encoding == ustctl_encode_none)
274	? "none"
275	: ((elem_type->u.basic.integer.encoding == ustctl_encode_UTF8)
276	? "UTF8"
277	: "ASCII"),
278	elem_type->u.basic.integer.base,
279	elem_type->u.basic.integer.reverse_byte_order ? bo_reverse : bo_native,
280	field->name,
281	field->name);
282	break;
283	}
284
285	case ustctl_atype_string:
286	/* Default encoding is UTF8 */
287	ret = lttng_metadata_printf(session,
288	" string%s _%s;\n",
289	field->type.u.basic.string.encoding == ustctl_encode_ASCII ?
290	" { encoding = ASCII; }" : "",
291	field->name);
292	break;
293	default:
294	return -EINVAL;
295	}
296	return ret;
297	}
298
299	static
300	int _lttng_context_metadata_statedump(struct ust_registry_session *session,
301	size_t nr_ctx_fields,
302	struct ustctl_field *ctx)
303	{
304	int ret = 0;
305	int i;
306
307	if (!ctx)
308	return 0;
309	for (i = 0; i < nr_ctx_fields; i++) {
310	const struct ustctl_field *field = &ctx[i];
311
312	ret = _lttng_field_statedump(session, field);
313	if (ret)
314	return ret;
315	}
316	return ret;
317	}
318
319	static
320	int _lttng_fields_metadata_statedump(struct ust_registry_session *session,
321	struct ust_registry_event *event)
322	{
323	int ret = 0;
324	int i;
325
326	for (i = 0; i < event->nr_fields; i++) {
327	const struct ustctl_field *field = &event->fields[i];
328
329	ret = _lttng_field_statedump(session, field);
330	if (ret)
331	return ret;
332	}
333	return ret;
334	}
335
336	/*
337	* Should be called with session registry mutex held.
338	*/
339	int ust_metadata_event_statedump(struct ust_registry_session *session,
340	struct ust_registry_channel *chan,
341	struct ust_registry_event *event)
342	{
343	int ret = 0;
344
345	/* Don't dump metadata events */
346	if (chan->chan_id == -1U)
347	return 0;
348
349	ret = lttng_metadata_printf(session,
350	"event {\n"
351	" name = \"%s\";\n"
352	" id = %u;\n"
353	" stream_id = %u;\n",
354	event->name,
355	event->id,
356	chan->chan_id);
357	if (ret)
358	goto end;
359
360	ret = lttng_metadata_printf(session,
361	" loglevel = %d;\n",
362	event->loglevel);
363	if (ret)
364	goto end;
365
366	if (event->model_emf_uri) {
367	ret = lttng_metadata_printf(session,
368	" model.emf.uri = \"%s\";\n",
369	event->model_emf_uri);
370	if (ret)
371	goto end;
372	}
373
374	#if 0 /* context for events not supported */
375	if (event->ctx) {
376	ret = lttng_metadata_printf(session,
377	" context := struct {\n");
378	if (ret)
379	goto end;
380	}
381	ret = _lttng_context_metadata_statedump(session, event->ctx);
382	if (ret)
383	goto end;
384	if (event->ctx) {
385	ret = lttng_metadata_printf(session,
386	" };\n");
387	if (ret)
388	goto end;
389	}
390	#endif
391	ret = lttng_metadata_printf(session,
392	" fields := struct {\n"
393	);
394	if (ret)
395	goto end;
396
397	ret = _lttng_fields_metadata_statedump(session, event);
398	if (ret)
399	goto end;
400
401	ret = lttng_metadata_printf(session,
402	" };\n"
403	"};\n\n");
404	if (ret)
405	goto end;
7972aab2	406	event->metadata_dumped = 1;
d0b96690 DG	407
	408	end:
	409	return ret;
	410	}
	411
	412	/*
	413	* Should be called with session registry mutex held.
	414	*/
	415	int ust_metadata_channel_statedump(struct ust_registry_session *session,
	416	struct ust_registry_channel *chan)
	417	{
	418	int ret = 0;
	419
	420	/* Don't dump metadata events */
	421	if (chan->chan_id == -1U)
	422	return 0;
	423
	424	if (!chan->header_type)
	425	return -EINVAL;
	426
	427	ret = lttng_metadata_printf(session,
	428	"stream {\n"
	429	" id = %u;\n"
	430	" event.header := %s;\n"
	431	" packet.context := struct packet_context;\n",
	432	chan->chan_id,
	433	chan->header_type == USTCTL_CHANNEL_HEADER_COMPACT ?
	434	"struct event_header_compact" :
	435	"struct event_header_large");
	436	if (ret)
	437	goto end;
	438
	439	if (chan->ctx_fields) {
	440	ret = lttng_metadata_printf(session,
	441	" event.context := struct {\n");
	442	if (ret)
	443	goto end;
	444	}
	445	ret = _lttng_context_metadata_statedump(session,
	446	chan->nr_ctx_fields,
	447	chan->ctx_fields);
	448	if (ret)
	449	goto end;
	450	if (chan->ctx_fields) {
	451	ret = lttng_metadata_printf(session,
	452	" };\n");
	453	if (ret)
	454	goto end;
	455	}
	456
	457	ret = lttng_metadata_printf(session,
	458	"};\n\n");
7972aab2 DG	459	/* Flag success of metadata dump. */
7972aab2 DG	460	chan->metadata_dumped = 1;
d0b96690 DG	461
	462	end:
	463	return ret;
	464	}
	465
	466	static
	467	int _lttng_stream_packet_context_declare(struct ust_registry_session *session)
	468	{
	469	return lttng_metadata_printf(session,
	470	"struct packet_context {\n"
	471	" uint64_clock_monotonic_t timestamp_begin;\n"
	472	" uint64_clock_monotonic_t timestamp_end;\n"
	473	" uint64_t content_size;\n"
	474	" uint64_t packet_size;\n"
	475	" unsigned long events_discarded;\n"
	476	" uint32_t cpu_id;\n"
	477	"};\n\n"
	478	);
	479	}
	480
	481	/*
	482	* Compact header:
	483	* id: range: 0 - 30.
	484	* id 31 is reserved to indicate an extended header.
	485	*
	486	* Large header:
	487	* id: range: 0 - 65534.
	488	* id 65535 is reserved to indicate an extended header.
	489	*/
	490	static
	491	int _lttng_event_header_declare(struct ust_registry_session *session)
	492	{
	493	return lttng_metadata_printf(session,
	494	"struct event_header_compact {\n"
	495	" enum : uint5_t { compact = 0 ... 30, extended = 31 } id;\n"
	496	" variant <id> {\n"
	497	" struct {\n"
	498	" uint27_clock_monotonic_t timestamp;\n"
	499	" } compact;\n"
	500	" struct {\n"
	501	" uint32_t id;\n"
	502	" uint64_clock_monotonic_t timestamp;\n"
	503	" } extended;\n"
	504	" } v;\n"
	505	"} align(%u);\n"
	506	"\n"
	507	"struct event_header_large {\n"
	508	" enum : uint16_t { compact = 0 ... 65534, extended = 65535 } id;\n"
	509	" variant <id> {\n"
	510	" struct {\n"
	511	" uint32_clock_monotonic_t timestamp;\n"
	512	" } compact;\n"
	513	" struct {\n"
	514	" uint32_t id;\n"
	515	" uint64_clock_monotonic_t timestamp;\n"
	516	" } extended;\n"
	517	" } v;\n"
	518	"} align(%u);\n\n",
	519	session->uint32_t_alignment,
	520	session->uint16_t_alignment
	521	);
	522	}
	523
d0b96690	524	static
8c645bb0	525	int measure_single_clock_offset(struct offset_sample *sample)
d0b96690	526	{
8c645bb0	527	uint64_t offset, monotonic[2], measure_delta, realtime;
fc0bb9fa	528	uint64_t tcf = trace_clock_freq();
d0b96690 DG	529	struct timespec rts = { 0, 0 };
	530	int ret;
	531
	532	monotonic[0] = trace_clock_read64();
	533	ret = clock_gettime(CLOCK_REALTIME, &rts);
8c645bb0 MD	534	if (ret < 0) {
	535	return ret;
	536	}
d0b96690	537	monotonic[1] = trace_clock_read64();
8c645bb0 MD	538	measure_delta = monotonic[1] - monotonic[0];
	539	if (measure_delta > sample->measure_delta) {
	540	/*
	541	* Discard value if it took longer to read than the best
	542	* sample so far.
	543	*/
	544	return 0;
	545	}
d0b96690	546	offset = (monotonic[0] + monotonic[1]) >> 1;
6e1b0543 MD	547	realtime = (uint64_t) rts.tv_sec * tcf;
	548	if (tcf == NSEC_PER_SEC) {
	549	realtime += rts.tv_nsec;
	550	} else {
	551	realtime += (uint64_t) rts.tv_nsec * tcf / NSEC_PER_SEC;
fc0bb9fa	552	}
d0b96690	553	offset = realtime - offset;
8c645bb0 MD	554	sample->offset = offset;
	555	sample->measure_delta = measure_delta;
	556	return 0;
d0b96690 DG	557	}
d0b96690 DG	558
8c645bb0 MD	559	/*
	560	* Approximation of NTP time of day to clock monotonic correlation,
	561	* taken at start of trace. Keep the measurement that took the less time
	562	* to complete, thus removing imprecision caused by preemption.
	563	*/
	564	static
	565	uint64_t measure_clock_offset(void)
	566	{
	567	int i;
	568	struct offset_sample offset_best_sample = {
	569	.offset = 0,
	570	.measure_delta = UINT64_MAX,
	571	};
	572
	573	for (i = 0; i < NR_CLOCK_OFFSET_SAMPLES; i++) {
	574	if (measure_single_clock_offset(&offset_best_sample)) {
	575	return 0;
	576	}
	577	}
	578	return offset_best_sample.offset;
	579	}
d0b96690 DG	580
	581	/*
	582	* Should be called with session registry mutex held.
	583	*/
	584	int ust_metadata_session_statedump(struct ust_registry_session *session,
af6142cf MD	585	struct ust_app *app,
	586	uint32_t major,
	587	uint32_t minor)
d0b96690 DG	588	{
	589	unsigned char *uuid_c;
	590	char uuid_s[UUID_STR_LEN],
	591	clock_uuid_s[UUID_STR_LEN];
	592	int ret = 0;
	593	char hostname[HOST_NAME_MAX];
	594
7972aab2	595	assert(session);
7972aab2	596
d0b96690 DG	597	uuid_c = session->uuid;
	598
	599	snprintf(uuid_s, sizeof(uuid_s),
	600	"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
	601	uuid_c[0], uuid_c[1], uuid_c[2], uuid_c[3],
	602	uuid_c[4], uuid_c[5], uuid_c[6], uuid_c[7],
	603	uuid_c[8], uuid_c[9], uuid_c[10], uuid_c[11],
	604	uuid_c[12], uuid_c[13], uuid_c[14], uuid_c[15]);
	605
d7ba1388 MD	606	/* For crash ABI */
	607	ret = lttng_metadata_printf(session,
	608	"/* CTF %u.%u */\n\n",
	609	CTF_SPEC_MAJOR,
	610	CTF_SPEC_MINOR);
	611	if (ret) {
	612	goto end;
	613	}
	614
d0b96690 DG	615	ret = lttng_metadata_printf(session,
	616	"typealias integer { size = 8; align = %u; signed = false; } := uint8_t;\n"
	617	"typealias integer { size = 16; align = %u; signed = false; } := uint16_t;\n"
	618	"typealias integer { size = 32; align = %u; signed = false; } := uint32_t;\n"
	619	"typealias integer { size = 64; align = %u; signed = false; } := uint64_t;\n"
	620	"typealias integer { size = %u; align = %u; signed = false; } := unsigned long;\n"
	621	"typealias integer { size = 5; align = 1; signed = false; } := uint5_t;\n"
	622	"typealias integer { size = 27; align = 1; signed = false; } := uint27_t;\n"
	623	"\n"
	624	"trace {\n"
	625	" major = %u;\n"
	626	" minor = %u;\n"
	627	" uuid = \"%s\";\n"
	628	" byte_order = %s;\n"
	629	" packet.header := struct {\n"
	630	" uint32_t magic;\n"
	631	" uint8_t uuid[16];\n"
	632	" uint32_t stream_id;\n"
	633	" };\n"
	634	"};\n\n",
	635	session->uint8_t_alignment,
	636	session->uint16_t_alignment,
	637	session->uint32_t_alignment,
	638	session->uint64_t_alignment,
	639	session->bits_per_long,
	640	session->long_alignment,
	641	CTF_SPEC_MAJOR,
	642	CTF_SPEC_MINOR,
	643	uuid_s,
	644	session->byte_order == BIG_ENDIAN ? "be" : "le"
	645	);
	646	if (ret)
	647	goto end;
	648
	649	/* ignore error, just use empty string if error. */
	650	hostname[0] = '\0';
	651	ret = gethostname(hostname, sizeof(hostname));
	652	if (ret && errno == ENAMETOOLONG)
	653	hostname[HOST_NAME_MAX - 1] = '\0';
	654	ret = lttng_metadata_printf(session,
	655	"env {\n"
	656	" hostname = \"%s\";\n"
	657	" domain = \"ust\";\n"
	658	" tracer_name = \"lttng-ust\";\n"
	659	" tracer_major = %u;\n"
af6142cf	660	" tracer_minor = %u;\n",
d0b96690	661	hostname,
af6142cf MD	662	major,
af6142cf MD	663	minor
d0b96690 DG	664	);
	665	if (ret)
	666	goto end;
	667
	668	/*
	669	* If per-application registry, we can output extra information
	670	* about the application.
	671	*/
	672	if (app) {
	673	ret = lttng_metadata_printf(session,
af6142cf	674	" tracer_patchlevel = %u;\n"
d0b96690	675	" vpid = %d;\n"
d88aee68	676	" procname = \"%s\";\n",
af6142cf	677	app->version.patchlevel,
d0b96690 DG	678	(int) app->pid,
	679	app->name
	680	);
	681	if (ret)
	682	goto end;
	683	}
	684
	685	ret = lttng_metadata_printf(session,
	686	"};\n\n"
	687	);
	688	if (ret)
	689	goto end;
	690
	691
	692	ret = lttng_metadata_printf(session,
	693	"clock {\n"
fc0bb9fa MD	694	" name = \"%s\";\n",
fc0bb9fa MD	695	trace_clock_name()
d0b96690 DG	696	);
	697	if (ret)
	698	goto end;
	699
	700	if (!trace_clock_uuid(clock_uuid_s)) {
	701	ret = lttng_metadata_printf(session,
	702	" uuid = \"%s\";\n",
	703	clock_uuid_s
	704	);
	705	if (ret)
	706	goto end;
	707	}
	708
	709	ret = lttng_metadata_printf(session,
fc0bb9fa	710	" description = \"%s\";\n"
d0b96690 DG	711	" freq = %" PRIu64 "; /* Frequency, in Hz */\n"
	712	" /* clock value offset from Epoch is: offset * (1/freq) */\n"
	713	" offset = %" PRIu64 ";\n"
	714	"};\n\n",
fc0bb9fa	715	trace_clock_description(),
d0b96690 DG	716	trace_clock_freq(),
	717	measure_clock_offset()
	718	);
	719	if (ret)
	720	goto end;
	721
	722	ret = lttng_metadata_printf(session,
	723	"typealias integer {\n"
	724	" size = 27; align = 1; signed = false;\n"
fc0bb9fa	725	" map = clock.%s.value;\n"
d0b96690 DG	726	"} := uint27_clock_monotonic_t;\n"
	727	"\n"
	728	"typealias integer {\n"
	729	" size = 32; align = %u; signed = false;\n"
fc0bb9fa	730	" map = clock.%s.value;\n"
d0b96690 DG	731	"} := uint32_clock_monotonic_t;\n"
	732	"\n"
	733	"typealias integer {\n"
	734	" size = 64; align = %u; signed = false;\n"
fc0bb9fa	735	" map = clock.%s.value;\n"
d0b96690	736	"} := uint64_clock_monotonic_t;\n\n",
fc0bb9fa	737	trace_clock_name(),
d0b96690	738	session->uint32_t_alignment,
fc0bb9fa MD	739	trace_clock_name(),
	740	session->uint64_t_alignment,
	741	trace_clock_name()
d0b96690 DG	742	);
	743	if (ret)
	744	goto end;
	745
	746	ret = _lttng_stream_packet_context_declare(session);
	747	if (ret)
	748	goto end;
	749
	750	ret = _lttng_event_header_declare(session);
	751	if (ret)
	752	goto end;
	753
	754	end:
	755	return ret;
	756	}