src/bin/lttng-relayd/session.hpp

   1 #ifndef _SESSION_H
   2 #define _SESSION_H
   3
   4 /*
   5  * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
   6  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   7  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-only
  10  *
  11  */
  12
  13 #include <limits.h>
  14 #include <inttypes.h>
  15 #include <pthread.h>
  16 #include <urcu/list.h>
  17 #include <urcu/ref.h>
  18
  19 #include <lttng/constant.h>
  20 #include <common/hashtable/hashtable.hpp>
  21 #include <common/uuid.hpp>
  22 #include <common/trace-chunk.hpp>
  23 #include <common/optional.hpp>
  24
  25 /*
  26  * Represents a session for the relay point of view
  27  */
  28 struct relay_session {
  29         /*
  30          * This session id is generated by the relay daemon to guarantee
  31          * its uniqueness even when serving multiple session daemons.
  32          * It is used to match a set of streams to their session.
  33          */
  34         uint64_t id;
  35         /*
  36          * ID of the session in the session daemon's domain.
  37          * This information is only provided by 2.11+ peers.
  38          */
  39         LTTNG_OPTIONAL(uint64_t) id_sessiond;
  40         /*
  41          * Only provided by 2.11+ peers. However, the UUID is set to 'nil' in
  42          * the other cases.
  43          */
  44         lttng_uuid sessiond_uuid;
  45         /*
  46          * Contains the creation time on the session daemon's end for 2.11+
  47          * peers. Otherwise, this contains the session creation time on the
  48          * relay daemon's end.
  49          */
  50         LTTNG_OPTIONAL(time_t) creation_time;
  51         /* Must _not_ be empty for 2.4+ peers. */
  52         char session_name[LTTNG_NAME_MAX];
  53         char hostname[LTTNG_HOST_NAME_MAX];
  54         char base_path[LTTNG_PATH_MAX];
  55         /*
  56          * Session output path relative to relayd's output path.
  57          * Will be empty when interacting with peers < 2.11 since their
  58          * streams' path are expressed relative to the relay daemon's
  59          * output path.
  60          */
  61         char output_path[LTTNG_PATH_MAX];
  62         uint32_t live_timer;
  63
  64         /* Session in snapshot mode. */
  65         bool snapshot;
  66
  67         /*
  68          * Session has no back reference to its connection because it
  69          * has a life-time that can be longer than the consumer connection's
  70          * life-time; a reference can still be held by the viewer
  71          * connection through the viewer streams.
  72          */
  73
  74         struct urcu_ref ref;
  75
  76         mutable pthread_mutex_t lock;
  77
  78         /* major/minor version used for this session. */
  79         uint32_t major;
  80         uint32_t minor;
  81
  82         bool viewer_attached;
  83         /* Tell if the session connection has been closed on the streaming side. */
  84         bool connection_closed;
  85
  86         /*
  87          * Tell if the session is currently living in a exiting relayd and
  88          * should be cleaned forcefully without waiting for pending data or
  89          * pending ctrl data.
  90          */
  91         bool aborted;
  92
  93         bool session_name_contains_creation_time;
  94         /* Whether session has performed an explicit rotation. */
  95         bool has_rotated;
  96
  97         /* Contains ctf_trace object of that session indexed by path name. */
  98         struct lttng_ht *ctf_traces_ht;
  99
 100         /*
 101          * This contains streams that are received on that connection.
 102          * It's used to store them until we get the streams sent
 103          * command. When this is received, we remove those streams from
 104          * the list and publish them.
 105          *
 106          * Updates are protected by the recv_list_lock.
 107          * Traversals are protected by RCU.
 108          * recv_list_lock also protects stream_count.
 109          */
 110         struct cds_list_head recv_list; /* RCU list. */
 111         uint32_t stream_count;
 112         pthread_mutex_t recv_list_lock;
 113
 114         /*
 115          * Flag checked and exchanged with uatomic_cmpxchg to tell the
 116          * viewer-side if new streams got added since the last check.
 117          */
 118         unsigned long new_streams;
 119
 120         /*
 121          * Node in the global session hash table.
 122          */
 123         struct lttng_ht_node_u64 session_n;
 124         /*
 125          * Member of the session list in struct relay_viewer_session.
 126          * Updates are protected by the relay_viewer_session
 127          * session_list_lock. Traversals are protected by RCU.
 128          */
 129         struct cds_list_head viewer_session_node;
 130         struct lttng_trace_chunk *current_trace_chunk;
 131         struct lttng_trace_chunk *pending_closure_trace_chunk;
 132         /*
 133          * Prevent live viewers from taking of copy of the chunk
 134          * while new chunk has a temporary directory name.
 135          */
 136         bool ongoing_rotation;
 137         struct lttng_directory_handle *output_directory;
 138         struct rcu_head rcu_node;       /* For call_rcu teardown. */
 139 };
 140
 141 struct relay_session *session_create(const char *session_name,
 142                 const char *hostname, const char *base_path,
 143                 uint32_t live_timer,
 144                 bool snapshot,
 145                 const lttng_uuid& sessiond_uuid,
 146                 const uint64_t *id_sessiond,
 147                 const uint64_t *current_chunk_id,
 148                 const time_t *creation_time,
 149                 uint32_t major,
 150                 uint32_t minor,
 151                 bool session_name_contains_creation_timestamp);
 152 struct relay_session *session_get_by_id(uint64_t id);
 153 bool session_get(struct relay_session *session);
 154 void session_put(struct relay_session *session);
 155
 156 int session_close(struct relay_session *session);
 157 int session_abort(struct relay_session *session);
 158
 159 bool session_has_ongoing_rotation(const struct relay_session *session);
 160
 161 void print_sessions(void);
 162
 163 #endif /* _SESSION_H */