[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 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;
	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]);

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