--- /dev/null
+/*
+ * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#ifndef LTTNG_UST_REGISTRY_SESSION_H
+#define LTTNG_UST_REGISTRY_SESSION_H
+
+#include "clock-class.hpp"
+#include "session.hpp"
+#include "trace-class.hpp"
+#include "ust-clock-class.hpp"
+#include "ust-registry-channel.hpp"
+
+#include <common/make-unique-wrapper.hpp>
+
+#include <cstdint>
+#include <ctime>
+#include <lttng/lttng.h>
+#include <string>
+#include <unistd.h>
+
+namespace lttng {
+namespace sessiond {
+namespace ust {
+
+class registry_session;
+
+namespace details {
+void locked_registry_session_release(registry_session *session);
+} /* namespace details */
+
+class registry_session : public lttng::sessiond::trace::trace_class {
+public:
+ using locked_ptr = std::unique_ptr<registry_session,
+ lttng::details::create_unique_class<registry_session,
+ details::locked_registry_session_release>::
+ deleter>;
+
+ virtual lttng_buffer_type get_buffering_scheme() const noexcept = 0;
+ locked_ptr lock();
+
+ void add_channel(uint64_t channel_key);
+ lttng::sessiond::ust::registry_channel& get_channel(uint64_t channel_key) const;
+ void remove_channel(uint64_t channel_key, bool notify);
+
+ void regenerate_metadata();
+ virtual ~registry_session();
+
+ /*
+ * With multiple writers and readers, use this lock to access
+ * the registry. Can nest within the ust app session lock.
+ * Also acts as a registry serialization lock. Used by registry
+ * readers to serialize the registry information sent from the
+ * sessiond to the consumerd.
+ * The consumer socket lock nests within this lock.
+ */
+ mutable pthread_mutex_t _lock;
+ /* Next channel ID available for a newly registered channel. */
+ uint32_t _next_channel_id = 0;
+ /* Once this value reaches UINT32_MAX, no more id can be allocated. */
+ uint32_t _used_channel_id = 0;
+ /* Next enumeration ID available. */
+ uint64_t _next_enum_id = 0;
+
+ /* Generated metadata. */
+ char *_metadata = nullptr; /* NOT null-terminated ! Use memcpy. */
+ size_t _metadata_len = 0, _metadata_alloc_len = 0;
+ /* Length of bytes sent to the consumer. */
+ size_t _metadata_len_sent = 0;
+ /* Current version of the metadata. */
+ uint64_t _metadata_version = 0;
+
+ /*
+ * Those fields are only used when a session is created with
+ * the --shm-path option. In this case, the metadata is output
+ * twice: once to the consumer, as ususal, but a second time
+ * also in the shm path directly. This is done so that a copy
+ * of the metadata that is as fresh as possible is available
+ * on the event of a crash.
+ *
+ * root_shm_path contains the shm-path provided by the user, along with
+ * the session's name and timestamp:
+ * e.g. /tmp/my_shm/my_session-20180612-135822
+ *
+ * shm_path contains the full path of the memory buffers:
+ * e.g. /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit
+ *
+ * metadata_path contains the full path to the metadata file that
+ * is kept for the "crash buffer" extraction:
+ * e.g.
+ * /tmp/my_shm/my_session-20180612-135822/ust/uid/1000/64-bit/metadata
+ *
+ * Note that this is not the trace's final metadata file. It is
+ * only meant to be used to read the contents of the ring buffers
+ * in the event of a crash.
+ *
+ * metadata_fd is a file descriptor that points to the file at
+ * 'metadata_path'.
+ */
+ char _root_shm_path[PATH_MAX] = {};
+ char _shm_path[PATH_MAX] = {};
+ char _metadata_path[PATH_MAX] = {};
+ /* File-backed metadata FD */
+ int _metadata_fd = -1;
+
+ /*
+ * Hash table containing channels sent by the UST tracer. MUST
+ * be accessed with a RCU read side lock acquired.
+ */
+ lttng_ht::uptr _channels;
+
+ /*
+ * Unique key to identify the metadata on the consumer side.
+ */
+ uint64_t _metadata_key = 0;
+ /*
+ * Indicates if the metadata is closed on the consumer side. This is to
+ * avoid double close of metadata when an application unregisters AND
+ * deletes its sessions.
+ */
+ bool _metadata_closed = false;
+
+ /* User and group owning the session. */
+ uid_t _uid = -1;
+ gid_t _gid = -1;
+
+ /* Enumerations table. */
+ lttng_ht::uptr _enums;
+
+ /*
+ * Copy of the tracer version when the first app is registered.
+ * It is used if we need to regenerate the metadata.
+ */
+ uint32_t _app_tracer_version_major = 0;
+ uint32_t _app_tracer_version_minor = 0;
+
+ /* The id of the parent session */
+ ltt_session::id_t _tracing_id = -1ULL;
+
+protected:
+ /* Prevent instanciation of this base class. */
+ registry_session(const struct lttng::sessiond::trace::abi& abi,
+ unsigned int app_tracer_version_major,
+ unsigned int app_tracer_version_minor,
+ const char *root_shm_path,
+ const char *shm_path,
+ uid_t euid,
+ gid_t egid,
+ uint64_t tracing_id);
+ virtual void _visit_environment(
+ lttng::sessiond::trace::trace_class_visitor& trace_class_visitor)
+ const override;
+ void _generate_metadata();
+
+private:
+ uint32_t _get_next_channel_id();
+ void _increase_metadata_size(size_t reservation_length);
+ void _append_metadata_fragment(const std::string& fragment);
+ void _reset_metadata();
+
+ virtual void _accept_on_clock_classes(
+ lttng::sessiond::trace::trace_class_visitor& trace_class_visitor)
+ const override final;
+ virtual void _accept_on_stream_classes(
+ lttng::sessiond::trace::trace_class_visitor& trace_class_visitor)
+ const override final;
+
+ lttng::sessiond::ust::clock_class _clock;
+ const lttng::sessiond::trace::trace_class_visitor::cuptr _metadata_generating_visitor;
+};
+
+} /* namespace ust */
+} /* namespace sessiond */
+} /* namespace lttng */
+
+#endif /* LTTNG_UST_REGISTRY_SESSION_H */
projects / lttng-tools.git / blobdiff