| 1 | /* |
| 2 | * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com> |
| 3 | * David Goulet <dgoulet@efficios.com> |
| 4 | * 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License, version 2 only, as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 13 | * more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License along with |
| 16 | * this program; if not, write to the Free Software Foundation, Inc., 51 |
| 17 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | */ |
| 19 | |
| 20 | #define _GNU_SOURCE |
| 21 | #define _LGPL_SOURCE |
| 22 | #include <common/common.h> |
| 23 | #include <urcu/rculist.h> |
| 24 | |
| 25 | #include "lttng-relayd.h" |
| 26 | #include "ctf-trace.h" |
| 27 | #include "session.h" |
| 28 | #include "stream.h" |
| 29 | |
| 30 | /* Global session id used in the session creation. */ |
| 31 | static uint64_t last_relay_session_id; |
| 32 | static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER; |
| 33 | |
| 34 | /* |
| 35 | * Create a new session by assigning a new session ID. |
| 36 | * |
| 37 | * Return allocated session or else NULL. |
| 38 | */ |
| 39 | struct relay_session *session_create(const char *session_name, |
| 40 | const char *hostname, uint32_t live_timer, |
| 41 | bool snapshot, uint32_t major, uint32_t minor) |
| 42 | { |
| 43 | struct relay_session *session; |
| 44 | |
| 45 | session = zmalloc(sizeof(*session)); |
| 46 | if (!session) { |
| 47 | PERROR("relay session zmalloc"); |
| 48 | goto error; |
| 49 | } |
| 50 | |
| 51 | session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING); |
| 52 | if (!session->ctf_traces_ht) { |
| 53 | free(session); |
| 54 | session = NULL; |
| 55 | goto error; |
| 56 | } |
| 57 | |
| 58 | pthread_mutex_lock(&last_relay_session_id_lock); |
| 59 | session->id = ++last_relay_session_id; |
| 60 | pthread_mutex_unlock(&last_relay_session_id_lock); |
| 61 | |
| 62 | session->major = major; |
| 63 | session->minor = minor; |
| 64 | lttng_ht_node_init_u64(&session->session_n, session->id); |
| 65 | urcu_ref_init(&session->ref); |
| 66 | CDS_INIT_LIST_HEAD(&session->recv_list); |
| 67 | pthread_mutex_init(&session->lock, NULL); |
| 68 | pthread_mutex_init(&session->reflock, NULL); |
| 69 | pthread_mutex_init(&session->recv_list_lock, NULL); |
| 70 | |
| 71 | strncpy(session->session_name, session_name, |
| 72 | sizeof(session->session_name)); |
| 73 | strncpy(session->hostname, hostname, |
| 74 | sizeof(session->hostname)); |
| 75 | session->live_timer = live_timer; |
| 76 | session->snapshot = snapshot; |
| 77 | |
| 78 | lttng_ht_add_unique_u64(sessions_ht, &session->session_n); |
| 79 | |
| 80 | error: |
| 81 | return session; |
| 82 | } |
| 83 | |
| 84 | /* Should be called with RCU read-side lock held. */ |
| 85 | bool session_get(struct relay_session *session) |
| 86 | { |
| 87 | bool has_ref = false; |
| 88 | |
| 89 | pthread_mutex_lock(&session->reflock); |
| 90 | if (session->ref.refcount != 0) { |
| 91 | has_ref = true; |
| 92 | urcu_ref_get(&session->ref); |
| 93 | } |
| 94 | pthread_mutex_unlock(&session->reflock); |
| 95 | |
| 96 | return has_ref; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * Lookup a session within the session hash table using the session id |
| 101 | * as key. A session reference is taken when a session is returned. |
| 102 | * session_put() must be called on that session. |
| 103 | * |
| 104 | * Return session or NULL if not found. |
| 105 | */ |
| 106 | struct relay_session *session_get_by_id(uint64_t id) |
| 107 | { |
| 108 | struct relay_session *session = NULL; |
| 109 | struct lttng_ht_node_u64 *node; |
| 110 | struct lttng_ht_iter iter; |
| 111 | |
| 112 | rcu_read_lock(); |
| 113 | lttng_ht_lookup(sessions_ht, &id, &iter); |
| 114 | node = lttng_ht_iter_get_node_u64(&iter); |
| 115 | if (!node) { |
| 116 | DBG("Session find by ID %" PRIu64 " id NOT found", id); |
| 117 | goto end; |
| 118 | } |
| 119 | session = caa_container_of(node, struct relay_session, session_n); |
| 120 | DBG("Session find by ID %" PRIu64 " id found", id); |
| 121 | if (!session_get(session)) { |
| 122 | session = NULL; |
| 123 | } |
| 124 | end: |
| 125 | rcu_read_unlock(); |
| 126 | return session; |
| 127 | } |
| 128 | |
| 129 | static void rcu_destroy_session(struct rcu_head *rcu_head) |
| 130 | { |
| 131 | struct relay_session *session = |
| 132 | caa_container_of(rcu_head, struct relay_session, |
| 133 | rcu_node); |
| 134 | |
| 135 | free(session); |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | * Delete session from the given hash table. |
| 140 | * |
| 141 | * Return lttng ht del error code being 0 on success and 1 on failure. |
| 142 | */ |
| 143 | static int session_delete(struct relay_session *session) |
| 144 | { |
| 145 | struct lttng_ht_iter iter; |
| 146 | |
| 147 | iter.iter.node = &session->session_n.node; |
| 148 | return lttng_ht_del(sessions_ht, &iter); |
| 149 | } |
| 150 | |
| 151 | |
| 152 | static void destroy_session(struct relay_session *session) |
| 153 | { |
| 154 | int ret; |
| 155 | |
| 156 | ret = session_delete(session); |
| 157 | assert(!ret); |
| 158 | /* |
| 159 | * Since each trace has a reference on the session, it means |
| 160 | * that if we are at the point where we teardown the session, no |
| 161 | * trace belonging to that session exist at this point. |
| 162 | */ |
| 163 | lttng_ht_destroy(session->ctf_traces_ht); |
| 164 | call_rcu(&session->rcu_node, rcu_destroy_session); |
| 165 | } |
| 166 | |
| 167 | void session_release(struct urcu_ref *ref) |
| 168 | { |
| 169 | struct relay_session *session = |
| 170 | caa_container_of(ref, struct relay_session, ref); |
| 171 | |
| 172 | destroy_session(session); |
| 173 | } |
| 174 | |
| 175 | void session_put(struct relay_session *session) |
| 176 | { |
| 177 | rcu_read_lock(); |
| 178 | pthread_mutex_lock(&session->reflock); |
| 179 | urcu_ref_put(&session->ref, session_release); |
| 180 | pthread_mutex_unlock(&session->reflock); |
| 181 | rcu_read_unlock(); |
| 182 | } |
| 183 | |
| 184 | int session_close(struct relay_session *session) |
| 185 | { |
| 186 | int ret = 0; |
| 187 | struct ctf_trace *trace; |
| 188 | struct lttng_ht_iter iter; |
| 189 | struct relay_stream *stream; |
| 190 | |
| 191 | pthread_mutex_lock(&session->lock); |
| 192 | DBG("closing session %" PRIu64 ": is conn already closed %d", |
| 193 | session->id, session->connection_closed); |
| 194 | if (session->connection_closed) { |
| 195 | ret = -1; |
| 196 | goto unlock; |
| 197 | } |
| 198 | session->connection_closed = true; |
| 199 | unlock: |
| 200 | pthread_mutex_unlock(&session->lock); |
| 201 | if (ret) { |
| 202 | return ret; |
| 203 | } |
| 204 | |
| 205 | rcu_read_lock(); |
| 206 | cds_lfht_for_each_entry(session->ctf_traces_ht->ht, |
| 207 | &iter.iter, trace, node.node) { |
| 208 | ret = ctf_trace_close(trace); |
| 209 | if (ret) { |
| 210 | goto rcu_unlock; |
| 211 | } |
| 212 | } |
| 213 | cds_list_for_each_entry_rcu(stream, &session->recv_list, |
| 214 | recv_node) { |
| 215 | /* Close streams which have not been published yet. */ |
| 216 | try_stream_close(stream); |
| 217 | } |
| 218 | rcu_unlock: |
| 219 | rcu_read_unlock(); |
| 220 | if (ret) { |
| 221 | return ret; |
| 222 | } |
| 223 | /* Put self-reference from create. */ |
| 224 | session_put(session); |
| 225 | return ret; |
| 226 | } |
| 227 | |
| 228 | void print_sessions(void) |
| 229 | { |
| 230 | struct lttng_ht_iter iter; |
| 231 | struct relay_session *session; |
| 232 | |
| 233 | rcu_read_lock(); |
| 234 | cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session, |
| 235 | session_n.node) { |
| 236 | if (!session_get(session)) { |
| 237 | continue; |
| 238 | } |
| 239 | DBG("session %p refcount %ld session %" PRIu64, |
| 240 | session, |
| 241 | session->ref.refcount, |
| 242 | session->id); |
| 243 | session_put(session); |
| 244 | } |
| 245 | rcu_read_unlock(); |
| 246 | } |