[lttng-tools.git] / src / bin / lttng-sessiond / ust-registry-session.cpp

/*
 * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#include "field.hpp"
#include "lttng-sessiond.hpp"
#include "notification-thread-commands.hpp"
#include "session.hpp"
#include "trace-class.hpp"
#include "tsdl-trace-class-visitor.hpp"
#include "ust-app.hpp"
#include "ust-field-convert.hpp"
#include "ust-registry.hpp"

#include <common/compat/directory-handle.hpp>
#include <common/error.hpp>
#include <common/exception.hpp>
#include <common/format.hpp>
#include <common/macros.hpp>
#include <common/make-unique.hpp>
#include <common/pthread-lock.hpp>
#include <common/runas.hpp>
#include <common/time.hpp>
#include <common/urcu.hpp>

#include <fcntl.h>
#include <functional>
#include <mutex>
#include <sstream>
#include <string>

namespace ls = lttng::sessiond;
namespace lst = lttng::sessiond::trace;
namespace lsu = lttng::sessiond::ust;

namespace {
lttng_uuid generate_uuid_or_throw()
{
	lttng_uuid new_uuid;

	if (lttng_uuid_generate(new_uuid)) {
		LTTNG_THROW_POSIX("Failed to generate UST uuid", errno);
	}

	return new_uuid;
}

int get_count_order(unsigned int count)
{
	int order;

	order = lttng_fls(count) - 1;
	if (count & (count - 1)) {
		order++;
	}

	LTTNG_ASSERT(order >= 0);
	return order;
}

void clear_metadata_file(int fd)
{
	const auto lseek_ret = lseek(fd, 0, SEEK_SET);
	if (lseek_ret < 0) {
		LTTNG_THROW_POSIX("Failed to seek to the beginning of the metadata file while clearing it", errno);
	}

	const auto ret = ftruncate(fd, 0);
	if (ret < 0) {
		LTTNG_THROW_POSIX("Failed to truncate the metadata file while clearing it", errno);
	}
}

/*
 * Validate that the id has reached the maximum allowed or not.
 */
bool is_max_channel_id(uint32_t id)
{
	return id == UINT32_MAX;
}

void destroy_channel_rcu(struct rcu_head *head)
{
	DIAGNOSTIC_PUSH
	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	lsu::registry_channel *chan =
		caa_container_of(head, lsu::registry_channel, _rcu_head);
	DIAGNOSTIC_POP

	delete chan;
}

/*
 * Destroy every element of the registry and free the memory. This does NOT
 * free the registry pointer since it might not have been allocated before so
 * it's the caller responsability.
 */
void destroy_channel(lsu::registry_channel *chan, bool notify)
{
	struct lttng_ht_iter iter;
	lttng::sessiond::ust::registry_event *event;
	enum lttng_error_code cmd_ret;

	LTTNG_ASSERT(chan);

	if (notify) {
		cmd_ret = notification_thread_command_remove_channel(
				the_notification_thread_handle,
				chan->_consumer_key, LTTNG_DOMAIN_UST);
		if (cmd_ret != LTTNG_OK) {
			ERR("Failed to remove channel from notification thread");
		}
	}

	if (chan->_events) {
		lttng::urcu::read_lock_guard read_lock_guard;

		/* Destroy all event associated with this registry. */
		DIAGNOSTIC_PUSH
		DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
		cds_lfht_for_each_entry(
				chan->_events->ht, &iter.iter, event, _node.node) {
			/* Delete the node from the ht and free it. */
			ust_registry_channel_destroy_event(chan, event);
		}
		DIAGNOSTIC_POP
	}

	call_rcu(&chan->_rcu_head, destroy_channel_rcu);
}
} /* namespace */

void lsu::details::locked_registry_session_release(lsu::registry_session *session)
{
	pthread_mutex_unlock(&session->_lock);
}

lsu::registry_session::registry_session(const struct lst::abi& in_abi,
		uint32_t major,
		uint32_t minor,
		const char *root_shm_path,
		const char *shm_path,
		uid_t euid,
		gid_t egid,
		uint64_t tracing_id) :
	lst::trace_class(in_abi, generate_uuid_or_throw()),
	_uid{euid},
	_gid{egid},
	_app_tracer_version_major{major},
	_app_tracer_version_minor{minor},
	_tracing_id{tracing_id},
	_metadata_generating_visitor{lttng::make_unique<ls::tsdl::trace_class_visitor>(
			abi, [this](const std::string& fragment) {
				_append_metadata_fragment(fragment);
			})}
{
	pthread_mutex_init(&_lock, NULL);
	strncpy(_root_shm_path, root_shm_path, sizeof(_root_shm_path));
	_root_shm_path[sizeof(_root_shm_path) - 1] = '\0';
	if (shm_path[0]) {
		strncpy(_shm_path, shm_path, sizeof(_shm_path));
		_shm_path[sizeof(_shm_path) - 1] = '\0';
		strncpy(_metadata_path, shm_path, sizeof(_metadata_path));
		_metadata_path[sizeof(_metadata_path) - 1] = '\0';
		strncat(_metadata_path, "/metadata",
				sizeof(_metadata_path) - strlen(_metadata_path) - 1);
	}

	if (_shm_path[0]) {
		if (run_as_mkdir_recursive(_shm_path, S_IRWXU | S_IRWXG, euid, egid)) {
			LTTNG_THROW_POSIX("run_as_mkdir_recursive", errno);
		}
	}

	if (_metadata_path[0]) {
		/* Create metadata file. */
		const int ret = run_as_open(_metadata_path, O_WRONLY | O_CREAT | O_EXCL,
				S_IRUSR | S_IWUSR, euid, egid);

		if (ret < 0) {
			std::stringstream ss;

			ss << "Opening metadata file '" << _metadata_path << "'";
			LTTNG_THROW_POSIX(ss.str(), errno);
		}

		_metadata_fd = ret;
	}

	_enums.reset(lttng_ht_new(0, LTTNG_HT_TYPE_STRING));
	if (!_enums) {
		LTTNG_THROW_POSIX("Failed to create enums hash table", ENOMEM);
	}

	/* hash/match functions are specified at call site. */
	_enums->match_fct = NULL;
	_enums->hash_fct = NULL;

	_channels.reset(lttng_ht_new(0, LTTNG_HT_TYPE_U64));
	if (!_channels) {
		LTTNG_THROW_POSIX("Failed to create channels hash table", ENOMEM);
	}
}

lsu::registry_session::~registry_session()
{
	int ret;
	struct lttng_ht_iter iter;
	lsu::registry_channel *chan;
	lsu::registry_enum *reg_enum;

	/* On error, EBUSY can be returned if lock. Code flow error. */
	ret = pthread_mutex_destroy(&_lock);
	LTTNG_ASSERT(!ret);

	if (_channels) {
		lttng::urcu::read_lock_guard read_lock_guard;

		/* Destroy all event associated with this registry. */
		DIAGNOSTIC_PUSH
		DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
		cds_lfht_for_each_entry(_channels->ht, &iter.iter, chan, _node.node) {
			/* Delete the node from the ht and free it. */
			ret = lttng_ht_del(_channels.get(), &iter);
			LTTNG_ASSERT(!ret);
			destroy_channel(chan, true);
		}
		DIAGNOSTIC_POP
	}

	free(_metadata);
	if (_metadata_fd >= 0) {
		ret = close(_metadata_fd);
		if (ret) {
			PERROR("close");
		}

		ret = run_as_unlink(_metadata_path, _uid, _gid);
		if (ret) {
			PERROR("unlink");
		}
	}

	if (_root_shm_path[0]) {
		/* Try to delete the directory hierarchy. */
		(void) run_as_rmdir_recursive(_root_shm_path, _uid, _gid,
				LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG);
	}

	/* Destroy the enum hash table */
	if (_enums) {
		rcu_read_lock();
		/* Destroy all enum entries associated with this registry. */
		DIAGNOSTIC_PUSH
		DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
		cds_lfht_for_each_entry (_enums->ht, &iter.iter, reg_enum, node.node) {
			ust_registry_destroy_enum(this, reg_enum);
		}
		DIAGNOSTIC_POP

		rcu_read_unlock();
	}
}

lsu::registry_session::locked_ptr lsu::registry_session::lock()
{
	pthread_mutex_lock(&_lock);
	return locked_ptr(this);
}

/*
 * Initialize registry with default values.
 */
void lsu::registry_session::add_channel(uint64_t key)
{
	lttng::pthread::lock_guard session_lock_guard(_lock);

	/*
	 * Assign a channel ID right now since the event notification comes
	 * *before* the channel notify so the ID needs to be set at this point so
	 * the metadata can be dumped for that event.
	 */
	if (is_max_channel_id(_used_channel_id)) {
		LTTNG_THROW_ERROR(fmt::format("Failed to allocate unique id for channel under session while adding channel"));
	}

	auto chan = new lsu::registry_channel(
			_get_next_channel_id(),
			/* Registered channel listener. */
			[this](const lsu::registry_channel& registered_channel) {
				/*
				 * Channel registration completed, serialize it's layout's
				 * description.
				 */
				registered_channel.accept(*_metadata_generating_visitor);
			},
			/* Added event listener. */
			[this](const lsu::registry_channel& channel,
					const lsu::registry_event& added_event) {
				/*
				 * The channel and its event classes will be dumped at once when
				 * it is registered. This check prevents event classes from being
				 * declared before their stream class.
				 */
				if (channel.is_registered()) {
					added_event.accept(*_metadata_generating_visitor);
				}
			});

	lttng::urcu::read_lock_guard rcu_read_lock_guard;
	lttng_ht_node_init_u64(&chan->_node, key);
	lttng_ht_add_unique_u64(_channels.get(), &chan->_node);
}

lttng::sessiond::ust::registry_channel& lsu::registry_session::get_channel(
		uint64_t channel_key) const
{
	lttng::urcu::read_lock_guard read_lock_guard;
	struct lttng_ht_node_u64 *node;
	struct lttng_ht_iter iter;

	ASSERT_LOCKED(_lock);

	lttng_ht_lookup(_channels.get(), &channel_key, &iter);
	node = lttng_ht_iter_get_node_u64(&iter);
	if (!node) {
		LTTNG_THROW_INVALID_ARGUMENT_ERROR(fmt::format(
				"Invalid channel key provided: channel key = {}", channel_key));
	}

	DIAGNOSTIC_PUSH
	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	auto chan = caa_container_of(node, lsu::registry_channel, _node);
	DIAGNOSTIC_POP
	return *chan;
}

void lsu::registry_session::remove_channel(uint64_t channel_key, bool notify)
{
	struct lttng_ht_iter iter;
	int ret;
	lttng::urcu::read_lock_guard read_lock_guard;

	ASSERT_LOCKED(_lock);
	auto& channel = get_channel(channel_key);

	iter.iter.node = &channel._node.node;
	ret = lttng_ht_del(_channels.get(), &iter);
	LTTNG_ASSERT(!ret);
	destroy_channel(&channel, notify);
}

void lsu::registry_session::_visit_environment(
		lttng::sessiond::trace::trace_class_visitor& visitor) const
{
	ASSERT_LOCKED(_lock);

	visitor.visit(lst::environment_field<const char *>("domain", "ust"));
	visitor.visit(lst::environment_field<const char *>("tracer_name", "lttng-ust"));
	visitor.visit(lst::environment_field<int64_t>("tracer_major", _app_tracer_version_major));
	visitor.visit(lst::environment_field<int64_t>("tracer_minor", _app_tracer_version_minor));
	visitor.visit(lst::environment_field<const char *>("tracer_buffering_scheme",
			get_buffering_scheme() == LTTNG_BUFFER_PER_PID ? "pid" : "uid"));
	visitor.visit(lst::environment_field<int64_t>("architecture_bit_width", abi.bits_per_long));

	{
		/* The caller already holds the session and session list locks. */
		ASSERT_SESSION_LIST_LOCKED();
		const auto session = lttng::sessiond::find_session_by_id(_tracing_id);

		LTTNG_ASSERT(session);
		ASSERT_LOCKED(session->lock);

		visitor.visit(lst::environment_field<const char *>("trace_name",
				session->has_auto_generated_name ? DEFAULT_SESSION_NAME :
									 session->name));
		visitor.visit(lst::environment_field<std::string>("trace_creation_datetime",
				lttng::utils::time_to_iso8601_str(session->creation_time)));
		visitor.visit(lst::environment_field<const char *>("hostname", session->hostname));
	}
}

void lsu::registry_session::_accept_on_clock_classes(lst::trace_class_visitor& visitor) const
{
	ASSERT_LOCKED(_lock);
	_clock.accept(visitor);
}

void lsu::registry_session::_accept_on_stream_classes(lst::trace_class_visitor& visitor) const
{
	ASSERT_LOCKED(_lock);

	std::vector<const lttng::sessiond::ust::registry_channel *> sorted_stream_classes;

	{
		lttng::urcu::read_lock_guard rcu_lock_guard;
		const lsu::registry_channel *channel;
		lttng_ht_iter channel_it;

		DIAGNOSTIC_PUSH
		DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
		cds_lfht_for_each_entry(_channels->ht, &channel_it.iter, channel, _node.node) {
			sorted_stream_classes.emplace_back(channel);
		}
		DIAGNOSTIC_POP
	}

	std::sort(sorted_stream_classes.begin(), sorted_stream_classes.end(),
			[](const lttng::sessiond::ust::registry_channel *a,
					const lttng::sessiond::ust::registry_channel *b) {
				return a->id < b->id;
			});

	for (const auto stream_class : sorted_stream_classes) {
		stream_class->accept(visitor);
	}
}

/*
 * Return next available channel id and increment the used counter. The
 * is_max_channel_id function MUST be called before in order to validate
 * if the maximum number of IDs have been reached. If not, it is safe to call
 * this function.
 *
 * Return a unique channel ID. If max is reached, the used_channel_id counter
 * is returned.
 */
uint32_t lsu::registry_session::_get_next_channel_id()
{
	if (is_max_channel_id(_used_channel_id)) {
		return _used_channel_id;
	}

	_used_channel_id++;
	return _next_channel_id++;
}

void lsu::registry_session::_increase_metadata_size(size_t reservation_length)
{
	const auto new_len = _metadata_len + reservation_length;
	auto new_alloc_len = new_len;
	const auto old_alloc_len = _metadata_alloc_len;

	/* Rounding the new allocation length to the next power of 2 would overflow. */
	if (new_alloc_len > (UINT32_MAX >> 1)) {
		LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the new size would overflow");
	}

	/* The current allocation length is already the largest we can afford. */
	if ((old_alloc_len << 1) > (UINT32_MAX >> 1)) {
		LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the max size was already reached");
	}

	if (new_alloc_len > old_alloc_len) {
		new_alloc_len = std::max<size_t>(
				1U << get_count_order(new_alloc_len), old_alloc_len << 1);

		auto newptr = (char *) realloc(_metadata, new_alloc_len);
		if (!newptr) {
			LTTNG_THROW_POSIX("Failed to allocate trace metadata storage", errno);
		}

		_metadata = newptr;

		/* We zero directly the memory from start of allocation. */
		memset(&_metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len);
		_metadata_alloc_len = new_alloc_len;
	}

	_metadata_len += reservation_length;
}

void lsu::registry_session::_append_metadata_fragment(const std::string& fragment)
{
	const auto offset = _metadata_len;

	_increase_metadata_size(fragment.size());
	memcpy(&_metadata[offset], fragment.c_str(), fragment.size());

	if (_metadata_fd >= 0) {
		const auto bytes_written =
				lttng_write(_metadata_fd, fragment.c_str(), fragment.size());

		if (bytes_written != fragment.size()) {
			LTTNG_THROW_POSIX("Failed to write trace metadata fragment to file",
					errno);
		}
	}
}

void lsu::registry_session::_reset_metadata()
{
	_metadata_len_sent = 0;
	memset(_metadata, 0, _metadata_alloc_len);
	_metadata_len = 0;

	if (_metadata_fd > 0) {
		/* Clear the metadata file's content. */
		clear_metadata_file(_metadata_fd);
	}
}

void lsu::registry_session::_generate_metadata()
{
	accept(*_metadata_generating_visitor);
}

void lsu::registry_session::regenerate_metadata()
{
	lttng::pthread::lock_guard registry_lock(_lock);

	_metadata_version++;
	_reset_metadata();
	_generate_metadata();
}
Commit	Line	Data
aeeb48c6 JG	1	/*
	2	* Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
	3	*
	4	* SPDX-License-Identifier: GPL-2.0-only
	5	*
	6	*/
	7
d7bfb9b0 JG	8	#include "field.hpp"
	9	#include "lttng-sessiond.hpp"
	10	#include "notification-thread-commands.hpp"
	11	#include "session.hpp"
	12	#include "trace-class.hpp"
	13	#include "tsdl-trace-class-visitor.hpp"
	14	#include "ust-app.hpp"
	15	#include "ust-field-convert.hpp"
aeeb48c6 JG	16	#include "ust-registry.hpp"
	17
	18	#include <common/compat/directory-handle.hpp>
	19	#include <common/error.hpp>
	20	#include <common/exception.hpp>
d7bfb9b0	21	#include <common/format.hpp>
17fd219b	22	#include <common/macros.hpp>
d7bfb9b0	23	#include <common/make-unique.hpp>
17fd219b	24	#include <common/pthread-lock.hpp>
aeeb48c6	25	#include <common/runas.hpp>
d7bfb9b0 JG	26	#include <common/time.hpp>
d7bfb9b0 JG	27	#include <common/urcu.hpp>
aeeb48c6 JG	28
aeeb48c6 JG	29	#include <fcntl.h>
d7bfb9b0 JG	30	#include <functional>
d7bfb9b0 JG	31	#include <mutex>
aeeb48c6 JG	32	#include <sstream>
	33	#include <string>
	34
d7bfb9b0 JG	35	namespace ls = lttng::sessiond;
	36	namespace lst = lttng::sessiond::trace;
	37	namespace lsu = lttng::sessiond::ust;
	38
	39	namespace {
	40	lttng_uuid generate_uuid_or_throw()
	41	{
	42	lttng_uuid new_uuid;
	43
	44	if (lttng_uuid_generate(new_uuid)) {
	45	LTTNG_THROW_POSIX("Failed to generate UST uuid", errno);
	46	}
	47
	48	return new_uuid;
	49	}
	50
	51	int get_count_order(unsigned int count)
	52	{
	53	int order;
	54
	55	order = lttng_fls(count) - 1;
	56	if (count & (count - 1)) {
	57	order++;
	58	}
	59
	60	LTTNG_ASSERT(order >= 0);
	61	return order;
	62	}
	63
	64	void clear_metadata_file(int fd)
	65	{
	66	const auto lseek_ret = lseek(fd, 0, SEEK_SET);
	67	if (lseek_ret < 0) {
	68	LTTNG_THROW_POSIX("Failed to seek to the beginning of the metadata file while clearing it", errno);
	69	}
	70
	71	const auto ret = ftruncate(fd, 0);
	72	if (ret < 0) {
	73	LTTNG_THROW_POSIX("Failed to truncate the metadata file while clearing it", errno);
	74	}
	75	}
	76
	77	/*
	78	* Validate that the id has reached the maximum allowed or not.
	79	*/
	80	bool is_max_channel_id(uint32_t id)
	81	{
	82	return id == UINT32_MAX;
	83	}
	84
	85	void destroy_channel_rcu(struct rcu_head *head)
	86	{
	87	DIAGNOSTIC_PUSH
	88	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	89	lsu::registry_channel *chan =
	90	caa_container_of(head, lsu::registry_channel, _rcu_head);
	91	DIAGNOSTIC_POP
	92
	93	delete chan;
	94	}
	95
	96	/*
	97	* Destroy every element of the registry and free the memory. This does NOT
	98	* free the registry pointer since it might not have been allocated before so
99	* it's the caller responsability.
100	*/
101	void destroy_channel(lsu::registry_channel *chan, bool notify)
102	{
103	struct lttng_ht_iter iter;
104	lttng::sessiond::ust::registry_event *event;
105	enum lttng_error_code cmd_ret;
106
107	LTTNG_ASSERT(chan);
108
109	if (notify) {
110	cmd_ret = notification_thread_command_remove_channel(
111	the_notification_thread_handle,
112	chan->_consumer_key, LTTNG_DOMAIN_UST);
113	if (cmd_ret != LTTNG_OK) {
114	ERR("Failed to remove channel from notification thread");
115	}
116	}
117
118	if (chan->_events) {
119	lttng::urcu::read_lock_guard read_lock_guard;
120
121	/* Destroy all event associated with this registry. */
122	DIAGNOSTIC_PUSH
123	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
124	cds_lfht_for_each_entry(
125	chan->_events->ht, &iter.iter, event, _node.node) {
126	/* Delete the node from the ht and free it. */
127	ust_registry_channel_destroy_event(chan, event);
128	}
129	DIAGNOSTIC_POP
130	}
131
132	call_rcu(&chan->_rcu_head, destroy_channel_rcu);
133	}
134	} /* namespace */
135
b0f2e8db	136	void lsu::details::locked_registry_session_release(lsu::registry_session *session)
d7bfb9b0 JG	137	{
	138	pthread_mutex_unlock(&session->_lock);
	139	}
	140
b0f2e8db	141	lsu::registry_session::registry_session(const struct lst::abi& in_abi,
aeeb48c6 JG	142	uint32_t major,
	143	uint32_t minor,
	144	const char *root_shm_path,
	145	const char *shm_path,
	146	uid_t euid,
	147	gid_t egid,
	148	uint64_t tracing_id) :
d7bfb9b0	149	lst::trace_class(in_abi, generate_uuid_or_throw()),
aeeb48c6 JG	150	_uid{euid},
	151	_gid{egid},
	152	_app_tracer_version_major{major},
	153	_app_tracer_version_minor{minor},
d7bfb9b0 JG	154	_tracing_id{tracing_id},
	155	_metadata_generating_visitor{lttng::make_unique<ls::tsdl::trace_class_visitor>(
	156	abi, [this](const std::string& fragment) {
	157	_append_metadata_fragment(fragment);
	158	})}
aeeb48c6 JG	159	{
	160	pthread_mutex_init(&_lock, NULL);
	161	strncpy(_root_shm_path, root_shm_path, sizeof(_root_shm_path));
	162	_root_shm_path[sizeof(_root_shm_path) - 1] = '\0';
	163	if (shm_path[0]) {
	164	strncpy(_shm_path, shm_path, sizeof(_shm_path));
	165	_shm_path[sizeof(_shm_path) - 1] = '\0';
	166	strncpy(_metadata_path, shm_path, sizeof(_metadata_path));
	167	_metadata_path[sizeof(_metadata_path) - 1] = '\0';
	168	strncat(_metadata_path, "/metadata",
	169	sizeof(_metadata_path) - strlen(_metadata_path) - 1);
	170	}
	171
	172	if (_shm_path[0]) {
	173	if (run_as_mkdir_recursive(_shm_path, S_IRWXU \| S_IRWXG, euid, egid)) {
	174	LTTNG_THROW_POSIX("run_as_mkdir_recursive", errno);
	175	}
	176	}
	177
	178	if (_metadata_path[0]) {
	179	/* Create metadata file. */
	180	const int ret = run_as_open(_metadata_path, O_WRONLY \| O_CREAT \| O_EXCL,
	181	S_IRUSR \| S_IWUSR, euid, egid);
	182
	183	if (ret < 0) {
	184	std::stringstream ss;
	185
	186	ss << "Opening metadata file '" << _metadata_path << "'";
	187	LTTNG_THROW_POSIX(ss.str(), errno);
	188	}
	189
	190	_metadata_fd = ret;
	191	}
	192
	193	_enums.reset(lttng_ht_new(0, LTTNG_HT_TYPE_STRING));
	194	if (!_enums) {
	195	LTTNG_THROW_POSIX("Failed to create enums hash table", ENOMEM);
	196	}
	197
	198	/* hash/match functions are specified at call site. */
	199	_enums->match_fct = NULL;
	200	_enums->hash_fct = NULL;
	201
	202	_channels.reset(lttng_ht_new(0, LTTNG_HT_TYPE_U64));
	203	if (!_channels) {
	204	LTTNG_THROW_POSIX("Failed to create channels hash table", ENOMEM);
	205	}
aeeb48c6 JG	206	}
aeeb48c6 JG	207
b0f2e8db	208	lsu::registry_session::~registry_session()
aeeb48c6 JG	209	{
	210	int ret;
	211	struct lttng_ht_iter iter;
d7bfb9b0 JG	212	lsu::registry_channel *chan;
d7bfb9b0 JG	213	lsu::registry_enum *reg_enum;
aeeb48c6 JG	214
	215	/* On error, EBUSY can be returned if lock. Code flow error. */
	216	ret = pthread_mutex_destroy(&_lock);
	217	LTTNG_ASSERT(!ret);
	218
	219	if (_channels) {
d7bfb9b0 JG	220	lttng::urcu::read_lock_guard read_lock_guard;
d7bfb9b0 JG	221
aeeb48c6	222	/* Destroy all event associated with this registry. */
d7bfb9b0 JG	223	DIAGNOSTIC_PUSH
	224	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	225	cds_lfht_for_each_entry(_channels->ht, &iter.iter, chan, _node.node) {
aeeb48c6 JG	226	/* Delete the node from the ht and free it. */
	227	ret = lttng_ht_del(_channels.get(), &iter);
	228	LTTNG_ASSERT(!ret);
d7bfb9b0	229	destroy_channel(chan, true);
aeeb48c6	230	}
d7bfb9b0	231	DIAGNOSTIC_POP
aeeb48c6 JG	232	}
	233
	234	free(_metadata);
	235	if (_metadata_fd >= 0) {
	236	ret = close(_metadata_fd);
	237	if (ret) {
	238	PERROR("close");
	239	}
	240
	241	ret = run_as_unlink(_metadata_path, _uid, _gid);
	242	if (ret) {
	243	PERROR("unlink");
	244	}
	245	}
	246
	247	if (_root_shm_path[0]) {
	248	/* Try to delete the directory hierarchy. */
	249	(void) run_as_rmdir_recursive(_root_shm_path, _uid, _gid,
	250	LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG);
	251	}
	252
	253	/* Destroy the enum hash table */
	254	if (_enums) {
	255	rcu_read_lock();
	256	/* Destroy all enum entries associated with this registry. */
d7bfb9b0 JG	257	DIAGNOSTIC_PUSH
d7bfb9b0 JG	258	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
aeeb48c6 JG	259	cds_lfht_for_each_entry (_enums->ht, &iter.iter, reg_enum, node.node) {
	260	ust_registry_destroy_enum(this, reg_enum);
	261	}
d7bfb9b0	262	DIAGNOSTIC_POP
aeeb48c6 JG	263
	264	rcu_read_unlock();
	265	}
	266	}
	267
b0f2e8db	268	lsu::registry_session::locked_ptr lsu::registry_session::lock()
aeeb48c6	269	{
d7bfb9b0 JG	270	pthread_mutex_lock(&_lock);
	271	return locked_ptr(this);
	272	}
	273
	274	/*
	275	* Initialize registry with default values.
	276	*/
b0f2e8db	277	void lsu::registry_session::add_channel(uint64_t key)
d7bfb9b0 JG	278	{
	279	lttng::pthread::lock_guard session_lock_guard(_lock);
	280
	281	/*
	282	* Assign a channel ID right now since the event notification comes
	283	* before the channel notify so the ID needs to be set at this point so
	284	* the metadata can be dumped for that event.
	285	*/
	286	if (is_max_channel_id(_used_channel_id)) {
	287	LTTNG_THROW_ERROR(fmt::format("Failed to allocate unique id for channel under session while adding channel"));
	288	}
	289
	290	auto chan = new lsu::registry_channel(
	291	_get_next_channel_id(),
	292	/* Registered channel listener. */
	293	[this](const lsu::registry_channel& registered_channel) {
	294	/*
	295	* Channel registration completed, serialize it's layout's
	296	* description.
	297	*/
	298	registered_channel.accept(*_metadata_generating_visitor);
	299	},
	300	/* Added event listener. */
	301	[this](const lsu::registry_channel& channel,
	302	const lsu::registry_event& added_event) {
	303	/*
	304	* The channel and its event classes will be dumped at once when
	305	* it is registered. This check prevents event classes from being
	306	* declared before their stream class.
	307	*/
	308	if (channel.is_registered()) {
	309	added_event.accept(*_metadata_generating_visitor);
	310	}
	311	});
	312
	313	lttng::urcu::read_lock_guard rcu_read_lock_guard;
	314	lttng_ht_node_init_u64(&chan->_node, key);
	315	lttng_ht_add_unique_u64(_channels.get(), &chan->_node);
	316	}
	317
b0f2e8db	318	lttng::sessiond::ust::registry_channel& lsu::registry_session::get_channel(
d7bfb9b0 JG	319	uint64_t channel_key) const
	320	{
	321	lttng::urcu::read_lock_guard read_lock_guard;
	322	struct lttng_ht_node_u64 *node;
	323	struct lttng_ht_iter iter;
	324
	325	ASSERT_LOCKED(_lock);
	326
	327	lttng_ht_lookup(_channels.get(), &channel_key, &iter);
	328	node = lttng_ht_iter_get_node_u64(&iter);
	329	if (!node) {
	330	LTTNG_THROW_INVALID_ARGUMENT_ERROR(fmt::format(
	331	"Invalid channel key provided: channel key = {}", channel_key));
	332	}
17fd219b	333
d7bfb9b0 JG	334	DIAGNOSTIC_PUSH
	335	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	336	auto chan = caa_container_of(node, lsu::registry_channel, _node);
	337	DIAGNOSTIC_POP
	338	return *chan;
	339	}
	340
b0f2e8db	341	void lsu::registry_session::remove_channel(uint64_t channel_key, bool notify)
d7bfb9b0 JG	342	{
	343	struct lttng_ht_iter iter;
	344	int ret;
	345	lttng::urcu::read_lock_guard read_lock_guard;
	346
	347	ASSERT_LOCKED(_lock);
	348	auto& channel = get_channel(channel_key);
	349
	350	iter.iter.node = &channel._node.node;
	351	ret = lttng_ht_del(_channels.get(), &iter);
	352	LTTNG_ASSERT(!ret);
	353	destroy_channel(&channel, notify);
	354	}
	355
b0f2e8db	356	void lsu::registry_session::_visit_environment(
d7bfb9b0 JG	357	lttng::sessiond::trace::trace_class_visitor& visitor) const
	358	{
	359	ASSERT_LOCKED(_lock);
	360
	361	visitor.visit(lst::environment_field<const char *>("domain", "ust"));
	362	visitor.visit(lst::environment_field<const char *>("tracer_name", "lttng-ust"));
	363	visitor.visit(lst::environment_field<int64_t>("tracer_major", _app_tracer_version_major));
	364	visitor.visit(lst::environment_field<int64_t>("tracer_minor", _app_tracer_version_minor));
	365	visitor.visit(lst::environment_field<const char *>("tracer_buffering_scheme",
	366	get_buffering_scheme() == LTTNG_BUFFER_PER_PID ? "pid" : "uid"));
	367	visitor.visit(lst::environment_field<int64_t>("architecture_bit_width", abi.bits_per_long));
	368
	369	{
	370	/* The caller already holds the session and session list locks. */
	371	ASSERT_SESSION_LIST_LOCKED();
	372	const auto session = lttng::sessiond::find_session_by_id(_tracing_id);
	373
	374	LTTNG_ASSERT(session);
	375	ASSERT_LOCKED(session->lock);
	376
	377	visitor.visit(lst::environment_field<const char *>("trace_name",
	378	session->has_auto_generated_name ? DEFAULT_SESSION_NAME :
	379	session->name));
	380	visitor.visit(lst::environment_field<std::string>("trace_creation_datetime",
	381	lttng::utils::time_to_iso8601_str(session->creation_time)));
	382	visitor.visit(lst::environment_field<const char *>("hostname", session->hostname));
aeeb48c6 JG	383	}
aeeb48c6 JG	384	}
d7bfb9b0	385
b0f2e8db	386	void lsu::registry_session::_accept_on_clock_classes(lst::trace_class_visitor& visitor) const
d7bfb9b0 JG	387	{
	388	ASSERT_LOCKED(_lock);
	389	_clock.accept(visitor);
	390	}
	391
b0f2e8db	392	void lsu::registry_session::_accept_on_stream_classes(lst::trace_class_visitor& visitor) const
d7bfb9b0 JG	393	{
	394	ASSERT_LOCKED(_lock);
	395
	396	std::vector<const lttng::sessiond::ust::registry_channel *> sorted_stream_classes;
	397
	398	{
	399	lttng::urcu::read_lock_guard rcu_lock_guard;
	400	const lsu::registry_channel *channel;
	401	lttng_ht_iter channel_it;
	402
	403	DIAGNOSTIC_PUSH
	404	DIAGNOSTIC_IGNORE_INVALID_OFFSETOF
	405	cds_lfht_for_each_entry(_channels->ht, &channel_it.iter, channel, _node.node) {
	406	sorted_stream_classes.emplace_back(channel);
	407	}
	408	DIAGNOSTIC_POP
	409	}
	410
	411	std::sort(sorted_stream_classes.begin(), sorted_stream_classes.end(),
	412	[](const lttng::sessiond::ust::registry_channel *a,
	413	const lttng::sessiond::ust::registry_channel *b) {
	414	return a->id < b->id;
	415	});
	416
	417	for (const auto stream_class : sorted_stream_classes) {
	418	stream_class->accept(visitor);
	419	}
	420	}
	421
	422	/*
	423	* Return next available channel id and increment the used counter. The
	424	* is_max_channel_id function MUST be called before in order to validate
	425	* if the maximum number of IDs have been reached. If not, it is safe to call
	426	* this function.
	427	*
	428	* Return a unique channel ID. If max is reached, the used_channel_id counter
	429	* is returned.
	430	*/
b0f2e8db	431	uint32_t lsu::registry_session::_get_next_channel_id()
d7bfb9b0 JG	432	{
	433	if (is_max_channel_id(_used_channel_id)) {
	434	return _used_channel_id;
	435	}
	436
	437	_used_channel_id++;
	438	return _next_channel_id++;
	439	}
	440
b0f2e8db	441	void lsu::registry_session::_increase_metadata_size(size_t reservation_length)
d7bfb9b0 JG	442	{
	443	const auto new_len = _metadata_len + reservation_length;
	444	auto new_alloc_len = new_len;
	445	const auto old_alloc_len = _metadata_alloc_len;
	446
	447	/* Rounding the new allocation length to the next power of 2 would overflow. */
	448	if (new_alloc_len > (UINT32_MAX >> 1)) {
	449	LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the new size would overflow");
	450	}
	451
	452	/* The current allocation length is already the largest we can afford. */
	453	if ((old_alloc_len << 1) > (UINT32_MAX >> 1)) {
	454	LTTNG_THROW_ERROR("Failed to reserve trace metadata storage as the max size was already reached");
	455	}
	456
	457	if (new_alloc_len > old_alloc_len) {
	458	new_alloc_len = std::max<size_t>(
	459	1U << get_count_order(new_alloc_len), old_alloc_len << 1);
	460
	461	auto newptr = (char *) realloc(_metadata, new_alloc_len);
	462	if (!newptr) {
	463	LTTNG_THROW_POSIX("Failed to allocate trace metadata storage", errno);
	464	}
	465
	466	_metadata = newptr;
	467
	468	/* We zero directly the memory from start of allocation. */
	469	memset(&_metadata[old_alloc_len], 0, new_alloc_len - old_alloc_len);
	470	_metadata_alloc_len = new_alloc_len;
	471	}
	472
	473	_metadata_len += reservation_length;
	474	}
	475
b0f2e8db	476	void lsu::registry_session::_append_metadata_fragment(const std::string& fragment)
d7bfb9b0 JG	477	{
	478	const auto offset = _metadata_len;
	479
	480	_increase_metadata_size(fragment.size());
	481	memcpy(&_metadata[offset], fragment.c_str(), fragment.size());
	482
	483	if (_metadata_fd >= 0) {
	484	const auto bytes_written =
	485	lttng_write(_metadata_fd, fragment.c_str(), fragment.size());
	486
	487	if (bytes_written != fragment.size()) {
	488	LTTNG_THROW_POSIX("Failed to write trace metadata fragment to file",
	489	errno);
	490	}
	491	}
	492	}
	493
b0f2e8db	494	void lsu::registry_session::_reset_metadata()
d7bfb9b0 JG	495	{
	496	_metadata_len_sent = 0;
	497	memset(_metadata, 0, _metadata_alloc_len);
	498	_metadata_len = 0;
	499
	500	if (_metadata_fd > 0) {
	501	/* Clear the metadata file's content. */
	502	clear_metadata_file(_metadata_fd);
	503	}
	504	}
	505
b0f2e8db	506	void lsu::registry_session::_generate_metadata()
d7bfb9b0 JG	507	{
	508	accept(*_metadata_generating_visitor);
	509	}
	510
b0f2e8db	511	void lsu::registry_session::regenerate_metadata()
d7bfb9b0 JG	512	{
	513	lttng::pthread::lock_guard registry_lock(_lock);
	514
	515	_metadata_version++;
	516	_reset_metadata();
	517	_generate_metadata();
	518	}