| 1 | /* |
| 2 | * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com> |
| 3 | * Copyright (C) 2013 David Goulet <dgoulet@efficios.com> |
| 4 | * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * SPDX-License-Identifier: GPL-2.0-only |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | #define _LGPL_SOURCE |
| 11 | #include "ctf-trace.hpp" |
| 12 | #include "live.hpp" |
| 13 | #include "lttng-relayd.hpp" |
| 14 | #include "session.hpp" |
| 15 | #include "stream.hpp" |
| 16 | #include "viewer-session.hpp" |
| 17 | #include "viewer-stream.hpp" |
| 18 | |
| 19 | #include <common/common.hpp> |
| 20 | #include <common/urcu.hpp> |
| 21 | |
| 22 | #include <urcu/rculist.h> |
| 23 | |
| 24 | /* Global session id used in the session creation. */ |
| 25 | static uint64_t last_viewer_session_id; |
| 26 | static pthread_mutex_t last_viewer_session_id_lock = PTHREAD_MUTEX_INITIALIZER; |
| 27 | |
| 28 | struct relay_viewer_session *viewer_session_create() |
| 29 | { |
| 30 | struct relay_viewer_session *vsession; |
| 31 | |
| 32 | vsession = zmalloc<relay_viewer_session>(); |
| 33 | if (!vsession) { |
| 34 | goto end; |
| 35 | } |
| 36 | pthread_mutex_lock(&last_viewer_session_id_lock); |
| 37 | vsession->id = ++last_viewer_session_id; |
| 38 | pthread_mutex_unlock(&last_viewer_session_id_lock); |
| 39 | CDS_INIT_LIST_HEAD(&vsession->session_list); |
| 40 | CDS_INIT_LIST_HEAD(&vsession->unannounced_stream_list); |
| 41 | pthread_mutex_init(&vsession->unannounced_stream_list_lock, nullptr); |
| 42 | lttng_ht_node_init_u64(&vsession->viewer_session_n, vsession->id); |
| 43 | lttng_ht_add_unique_u64(viewer_sessions_ht, &vsession->viewer_session_n); |
| 44 | end: |
| 45 | return vsession; |
| 46 | } |
| 47 | |
| 48 | int viewer_session_set_trace_chunk_copy(struct relay_viewer_session *vsession, |
| 49 | struct lttng_trace_chunk *relay_session_trace_chunk) |
| 50 | { |
| 51 | int ret = 0; |
| 52 | struct lttng_trace_chunk *viewer_chunk; |
| 53 | |
| 54 | lttng_trace_chunk_put(vsession->current_trace_chunk); |
| 55 | vsession->current_trace_chunk = nullptr; |
| 56 | |
| 57 | DBG("Copying relay session's current trace chunk to the viewer session"); |
| 58 | if (!relay_session_trace_chunk) { |
| 59 | goto end; |
| 60 | } |
| 61 | |
| 62 | viewer_chunk = lttng_trace_chunk_copy(relay_session_trace_chunk); |
| 63 | if (!viewer_chunk) { |
| 64 | ERR("Failed to create a viewer trace chunk from the relay session's current chunk"); |
| 65 | ret = -1; |
| 66 | goto end; |
| 67 | } |
| 68 | |
| 69 | vsession->current_trace_chunk = viewer_chunk; |
| 70 | end: |
| 71 | return ret; |
| 72 | } |
| 73 | |
| 74 | /* The existence of session must be guaranteed by the caller. */ |
| 75 | enum lttng_viewer_attach_return_code viewer_session_attach(struct relay_viewer_session *vsession, |
| 76 | struct relay_session *session) |
| 77 | { |
| 78 | enum lttng_viewer_attach_return_code viewer_attach_status = LTTNG_VIEWER_ATTACH_OK; |
| 79 | |
| 80 | ASSERT_LOCKED(session->lock); |
| 81 | |
| 82 | /* Will not fail, as per the ownership guarantee. */ |
| 83 | if (!session_get(session)) { |
| 84 | viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK; |
| 85 | goto end; |
| 86 | } |
| 87 | if (session->viewer_attached) { |
| 88 | viewer_attach_status = LTTNG_VIEWER_ATTACH_ALREADY; |
| 89 | } else { |
| 90 | int ret; |
| 91 | |
| 92 | session->viewer_attached = true; |
| 93 | |
| 94 | ret = viewer_session_set_trace_chunk_copy(vsession, session->current_trace_chunk); |
| 95 | if (ret) { |
| 96 | /* |
| 97 | * The live protocol does not define a generic error |
| 98 | * value for the "attach" command. The "unknown" |
| 99 | * status is used so that the viewer may handle this |
| 100 | * failure as if the session didn't exist anymore. |
| 101 | */ |
| 102 | DBG("Failed to create a viewer trace chunk from the current trace chunk of session \"%s\", returning LTTNG_VIEWER_ATTACH_UNK", |
| 103 | session->session_name); |
| 104 | viewer_attach_status = LTTNG_VIEWER_ATTACH_UNK; |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | if (viewer_attach_status == LTTNG_VIEWER_ATTACH_OK) { |
| 109 | pthread_mutex_lock(&vsession->session_list_lock); |
| 110 | /* Ownership is transfered to the list. */ |
| 111 | cds_list_add_rcu(&session->viewer_session_node, &vsession->session_list); |
| 112 | pthread_mutex_unlock(&vsession->session_list_lock); |
| 113 | |
| 114 | /* |
| 115 | * Immediately create new viewer streams for the attached session |
| 116 | * so that the viewer streams hold a reference on the any relay |
| 117 | * streams that could be unpublished between now and the next |
| 118 | * GET_NEW_STREAMS command from the live viewer. |
| 119 | */ |
| 120 | uint32_t created = 0; |
| 121 | uint32_t total = 0; |
| 122 | uint32_t unsent = 0; |
| 123 | bool closed = false; |
| 124 | const int make_viewer_streams_ret = make_viewer_streams(session, |
| 125 | vsession, |
| 126 | LTTNG_VIEWER_SEEK_BEGINNING, |
| 127 | &total, |
| 128 | &unsent, |
| 129 | &created, |
| 130 | &closed); |
| 131 | |
| 132 | if (make_viewer_streams_ret == 0) { |
| 133 | DBG("Created %d new viewer streams while attaching to relay session %" PRIu64, |
| 134 | created, |
| 135 | session->id); |
| 136 | } else { |
| 137 | /* |
| 138 | * Warning, since the creation of the streams will be retried when |
| 139 | * the viewer next sends the GET_NEW_STREAMS commands. |
| 140 | */ |
| 141 | WARN("Failed to create new viewer streams while attaching to relay session %" PRIu64 |
| 142 | ", ret=%d, total=%d, unsent=%d, created=%d, closed=%d", |
| 143 | session->id, |
| 144 | make_viewer_streams_ret, |
| 145 | total, |
| 146 | unsent, |
| 147 | created, |
| 148 | closed); |
| 149 | } |
| 150 | } else { |
| 151 | /* Put our local ref. */ |
| 152 | session_put(session); |
| 153 | } |
| 154 | end: |
| 155 | return viewer_attach_status; |
| 156 | } |
| 157 | |
| 158 | /* The existence of session must be guaranteed by the caller. */ |
| 159 | static int viewer_session_detach(struct relay_viewer_session *vsession, |
| 160 | struct relay_session *session) |
| 161 | { |
| 162 | int ret = 0; |
| 163 | |
| 164 | pthread_mutex_lock(&session->lock); |
| 165 | if (!session->viewer_attached) { |
| 166 | ret = -1; |
| 167 | } else { |
| 168 | session->viewer_attached = false; |
| 169 | } |
| 170 | |
| 171 | if (!ret) { |
| 172 | pthread_mutex_lock(&vsession->session_list_lock); |
| 173 | cds_list_del_rcu(&session->viewer_session_node); |
| 174 | pthread_mutex_unlock(&vsession->session_list_lock); |
| 175 | /* Release reference held by the list. */ |
| 176 | session_put(session); |
| 177 | } |
| 178 | |
| 179 | /* Safe since we know the session exists. */ |
| 180 | pthread_mutex_unlock(&session->lock); |
| 181 | return ret; |
| 182 | } |
| 183 | |
| 184 | void viewer_session_destroy(struct relay_viewer_session *vsession) |
| 185 | { |
| 186 | struct lttng_ht_iter iter; |
| 187 | |
| 188 | LTTNG_ASSERT(cds_list_empty(&vsession->unannounced_stream_list)); |
| 189 | |
| 190 | iter.iter.node = &vsession->viewer_session_n.node; |
| 191 | lttng_ht_del(viewer_sessions_ht, &iter); |
| 192 | lttng_trace_chunk_put(vsession->current_trace_chunk); |
| 193 | free(vsession); |
| 194 | } |
| 195 | |
| 196 | /* |
| 197 | * Release ownership of all the streams of one session and detach the viewer. |
| 198 | */ |
| 199 | void viewer_session_close_one_session(struct relay_viewer_session *vsession, |
| 200 | struct relay_session *session) |
| 201 | { |
| 202 | /* |
| 203 | * TODO: improvement: create more efficient list of |
| 204 | * vstream per session. |
| 205 | */ |
| 206 | for (auto *vstream : |
| 207 | lttng::urcu::lfht_iteration_adapter<relay_viewer_stream, |
| 208 | decltype(relay_viewer_stream::stream_n), |
| 209 | &relay_viewer_stream::stream_n>( |
| 210 | *viewer_streams_ht->ht)) { |
| 211 | if (!viewer_stream_get(vstream)) { |
| 212 | continue; |
| 213 | } |
| 214 | |
| 215 | if (vstream->stream->trace->session != session) { |
| 216 | viewer_stream_put(vstream); |
| 217 | continue; |
| 218 | } |
| 219 | /* Put local reference. */ |
| 220 | viewer_stream_put(vstream); |
| 221 | /* |
| 222 | * We have reached one of the viewer stream's lifetime |
| 223 | * end condition. This "put" will cause the proper |
| 224 | * teardown of the viewer stream. |
| 225 | */ |
| 226 | viewer_stream_put(vstream); |
| 227 | } |
| 228 | |
| 229 | for (auto *vstream : |
| 230 | lttng::urcu::rcu_list_iteration_adapter<relay_viewer_stream, |
| 231 | &relay_viewer_stream::viewer_stream_node>( |
| 232 | vsession->unannounced_stream_list)) { |
| 233 | if (!viewer_stream_get(vstream)) { |
| 234 | continue; |
| 235 | } |
| 236 | if (vstream->stream->trace->session != session) { |
| 237 | viewer_stream_put(vstream); |
| 238 | continue; |
| 239 | } |
| 240 | pthread_mutex_lock(&vsession->unannounced_stream_list_lock); |
| 241 | cds_list_del_rcu(&vstream->viewer_stream_node); |
| 242 | pthread_mutex_unlock(&vsession->unannounced_stream_list_lock); |
| 243 | /* Local reference */ |
| 244 | viewer_stream_put(vstream); |
| 245 | /* Reference from unannounced_stream_list */ |
| 246 | viewer_stream_put(vstream); |
| 247 | } |
| 248 | |
| 249 | lttng_trace_chunk_put(vsession->current_trace_chunk); |
| 250 | vsession->current_trace_chunk = nullptr; |
| 251 | viewer_session_detach(vsession, session); |
| 252 | } |
| 253 | |
| 254 | void viewer_session_close(struct relay_viewer_session *vsession) |
| 255 | { |
| 256 | for (auto *session : |
| 257 | lttng::urcu::rcu_list_iteration_adapter<relay_session, |
| 258 | &relay_session::viewer_session_node>( |
| 259 | vsession->session_list)) { |
| 260 | viewer_session_close_one_session(vsession, session); |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | /* |
| 265 | * Check if a connection is attached to a session. |
| 266 | * Return 1 if attached, 0 if not attached, a negative value on error. |
| 267 | */ |
| 268 | int viewer_session_is_attached(struct relay_viewer_session *vsession, struct relay_session *session) |
| 269 | { |
| 270 | int found = 0; |
| 271 | |
| 272 | pthread_mutex_lock(&session->lock); |
| 273 | if (!vsession) { |
| 274 | goto end; |
| 275 | } |
| 276 | if (!session->viewer_attached) { |
| 277 | goto end; |
| 278 | } |
| 279 | |
| 280 | for (auto *session_it : |
| 281 | lttng::urcu::rcu_list_iteration_adapter<relay_session, |
| 282 | &relay_session::viewer_session_node>( |
| 283 | vsession->session_list)) { |
| 284 | if (session == session_it) { |
| 285 | found = 1; |
| 286 | break; |
| 287 | } |
| 288 | } |
| 289 | |
| 290 | end: |
| 291 | pthread_mutex_unlock(&session->lock); |
| 292 | return found; |
| 293 | } |