| 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 <assert.h> |
| 23 | |
| 24 | #include <common/common.h> |
| 25 | #include <common/utils.h> |
| 26 | #include <urcu/rculist.h> |
| 27 | |
| 28 | #include "ctf-trace.h" |
| 29 | #include "lttng-relayd.h" |
| 30 | #include "stream.h" |
| 31 | |
| 32 | static uint64_t last_relay_ctf_trace_id; |
| 33 | static pthread_mutex_t last_relay_ctf_trace_id_lock = PTHREAD_MUTEX_INITIALIZER; |
| 34 | |
| 35 | static void rcu_destroy_ctf_trace(struct rcu_head *rcu_head) |
| 36 | { |
| 37 | struct ctf_trace *trace = |
| 38 | caa_container_of(rcu_head, struct ctf_trace, rcu_node); |
| 39 | |
| 40 | free(trace); |
| 41 | } |
| 42 | |
| 43 | /* |
| 44 | * Destroy a ctf trace and all stream contained in it. |
| 45 | * |
| 46 | * MUST be called with the RCU read side lock. |
| 47 | */ |
| 48 | void ctf_trace_destroy(struct ctf_trace *trace) |
| 49 | { |
| 50 | /* |
| 51 | * Getting to this point, every stream referenced by that trace |
| 52 | * have put back their ref since the've been closed by the |
| 53 | * control side. |
| 54 | */ |
| 55 | assert(cds_list_empty(&trace->stream_list)); |
| 56 | session_put(trace->session); |
| 57 | trace->session = NULL; |
| 58 | call_rcu(&trace->rcu_node, rcu_destroy_ctf_trace); |
| 59 | } |
| 60 | |
| 61 | void ctf_trace_release(struct urcu_ref *ref) |
| 62 | { |
| 63 | struct ctf_trace *trace = |
| 64 | caa_container_of(ref, struct ctf_trace, ref); |
| 65 | int ret; |
| 66 | struct lttng_ht_iter iter; |
| 67 | |
| 68 | iter.iter.node = &trace->node.node; |
| 69 | ret = lttng_ht_del(trace->session->ctf_traces_ht, &iter); |
| 70 | assert(!ret); |
| 71 | ctf_trace_destroy(trace); |
| 72 | } |
| 73 | |
| 74 | /* |
| 75 | * Should be called with RCU read-side lock held. |
| 76 | */ |
| 77 | bool ctf_trace_get(struct ctf_trace *trace) |
| 78 | { |
| 79 | bool has_ref = false; |
| 80 | |
| 81 | /* Confirm that the trace refcount has not reached 0. */ |
| 82 | pthread_mutex_lock(&trace->reflock); |
| 83 | if (trace->ref.refcount != 0) { |
| 84 | has_ref = true; |
| 85 | urcu_ref_get(&trace->ref); |
| 86 | } |
| 87 | pthread_mutex_unlock(&trace->reflock); |
| 88 | |
| 89 | return has_ref; |
| 90 | } |
| 91 | |
| 92 | /* |
| 93 | * Create and return an allocated ctf_trace. NULL on error. |
| 94 | * There is no "open" and "close" for a ctf_trace, but rather just a |
| 95 | * create and refcounting. Whenever all the streams belonging to a trace |
| 96 | * put their reference, its refcount drops to 0. |
| 97 | */ |
| 98 | static struct ctf_trace *ctf_trace_create(struct relay_session *session, |
| 99 | char *path_name) |
| 100 | { |
| 101 | struct ctf_trace *trace; |
| 102 | |
| 103 | trace = zmalloc(sizeof(*trace)); |
| 104 | if (!trace) { |
| 105 | PERROR("ctf_trace alloc"); |
| 106 | goto error; |
| 107 | } |
| 108 | |
| 109 | if (!session_get(session)) { |
| 110 | ERR("Cannot get session"); |
| 111 | free(trace); |
| 112 | trace = NULL; |
| 113 | goto error; |
| 114 | } |
| 115 | trace->session = session; |
| 116 | |
| 117 | CDS_INIT_LIST_HEAD(&trace->stream_list); |
| 118 | |
| 119 | pthread_mutex_lock(&last_relay_ctf_trace_id_lock); |
| 120 | trace->id = ++last_relay_ctf_trace_id; |
| 121 | pthread_mutex_unlock(&last_relay_ctf_trace_id_lock); |
| 122 | |
| 123 | lttng_ht_node_init_str(&trace->node, path_name); |
| 124 | trace->session = session; |
| 125 | urcu_ref_init(&trace->ref); |
| 126 | pthread_mutex_init(&trace->lock, NULL); |
| 127 | pthread_mutex_init(&trace->reflock, NULL); |
| 128 | pthread_mutex_init(&trace->stream_list_lock, NULL); |
| 129 | lttng_ht_add_str(session->ctf_traces_ht, &trace->node); |
| 130 | |
| 131 | DBG("Created ctf_trace %" PRIu64 " with path: %s", trace->id, path_name); |
| 132 | |
| 133 | error: |
| 134 | return trace; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Return a ctf_trace if found by id in the given hash table else NULL. |
| 139 | * Hold a reference on the ctf_trace, and must be paired with |
| 140 | * ctf_trace_put(). |
| 141 | */ |
| 142 | struct ctf_trace *ctf_trace_get_by_path_or_create(struct relay_session *session, |
| 143 | char *path_name) |
| 144 | { |
| 145 | struct lttng_ht_node_str *node; |
| 146 | struct lttng_ht_iter iter; |
| 147 | struct ctf_trace *trace = NULL; |
| 148 | |
| 149 | rcu_read_lock(); |
| 150 | lttng_ht_lookup(session->ctf_traces_ht, (void *) path_name, &iter); |
| 151 | node = lttng_ht_iter_get_node_str(&iter); |
| 152 | if (!node) { |
| 153 | DBG("CTF Trace path %s not found", path_name); |
| 154 | goto end; |
| 155 | } |
| 156 | trace = caa_container_of(node, struct ctf_trace, node); |
| 157 | if (!ctf_trace_get(trace)) { |
| 158 | trace = NULL; |
| 159 | } |
| 160 | end: |
| 161 | rcu_read_unlock(); |
| 162 | if (!trace) { |
| 163 | /* Try to create */ |
| 164 | trace = ctf_trace_create(session, path_name); |
| 165 | } |
| 166 | return trace; |
| 167 | } |
| 168 | |
| 169 | void ctf_trace_put(struct ctf_trace *trace) |
| 170 | { |
| 171 | rcu_read_lock(); |
| 172 | pthread_mutex_lock(&trace->reflock); |
| 173 | urcu_ref_put(&trace->ref, ctf_trace_release); |
| 174 | pthread_mutex_unlock(&trace->reflock); |
| 175 | rcu_read_unlock(); |
| 176 | } |
| 177 | |
| 178 | int ctf_trace_close(struct ctf_trace *trace) |
| 179 | { |
| 180 | struct relay_stream *stream; |
| 181 | |
| 182 | rcu_read_lock(); |
| 183 | cds_list_for_each_entry_rcu(stream, &trace->stream_list, |
| 184 | stream_node) { |
| 185 | /* |
| 186 | * Close the stream. |
| 187 | */ |
| 188 | stream_close(stream); |
| 189 | } |
| 190 | rcu_read_unlock(); |
| 191 | /* |
| 192 | * Since all references to the trace are held by its streams, we |
| 193 | * don't need to do any self-ref put. |
| 194 | */ |
| 195 | return 0; |
| 196 | } |
| 197 | |
| 198 | struct relay_viewer_stream *ctf_trace_get_viewer_metadata_stream(struct ctf_trace *trace) |
| 199 | { |
| 200 | struct relay_viewer_stream *vstream; |
| 201 | |
| 202 | rcu_read_lock(); |
| 203 | vstream = rcu_dereference(trace->viewer_metadata_stream); |
| 204 | if (!vstream) { |
| 205 | goto end; |
| 206 | } |
| 207 | if (!viewer_stream_get(vstream)) { |
| 208 | vstream = NULL; |
| 209 | } |
| 210 | end: |
| 211 | rcu_read_unlock(); |
| 212 | return vstream; |
| 213 | } |