| 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 | |
| 12 | #include "ctf-trace.hpp" |
| 13 | #include "lttng-relayd.hpp" |
| 14 | #include "stream.hpp" |
| 15 | |
| 16 | #include <common/common.hpp> |
| 17 | #include <common/utils.hpp> |
| 18 | |
| 19 | #include <urcu/rculist.h> |
| 20 | |
| 21 | static uint64_t last_relay_ctf_trace_id; |
| 22 | static pthread_mutex_t last_relay_ctf_trace_id_lock = PTHREAD_MUTEX_INITIALIZER; |
| 23 | |
| 24 | static void rcu_destroy_ctf_trace(struct rcu_head *rcu_head) |
| 25 | { |
| 26 | struct ctf_trace *trace = lttng::utils::container_of(rcu_head, &ctf_trace::rcu_node); |
| 27 | |
| 28 | free(trace); |
| 29 | } |
| 30 | |
| 31 | /* |
| 32 | * Destroy a ctf trace and all stream contained in it. |
| 33 | * |
| 34 | * MUST be called with the RCU read side lock. |
| 35 | */ |
| 36 | static void ctf_trace_destroy(struct ctf_trace *trace) |
| 37 | { |
| 38 | /* |
| 39 | * Getting to this point, every stream referenced by that trace |
| 40 | * have put back their ref since the've been closed by the |
| 41 | * control side. |
| 42 | */ |
| 43 | LTTNG_ASSERT(cds_list_empty(&trace->stream_list)); |
| 44 | ASSERT_RCU_READ_LOCKED(); |
| 45 | |
| 46 | session_put(trace->session); |
| 47 | trace->session = nullptr; |
| 48 | free(trace->path); |
| 49 | trace->path = nullptr; |
| 50 | call_rcu(&trace->rcu_node, rcu_destroy_ctf_trace); |
| 51 | } |
| 52 | |
| 53 | static void ctf_trace_release(struct urcu_ref *ref) |
| 54 | { |
| 55 | struct ctf_trace *trace = lttng::utils::container_of(ref, &ctf_trace::ref); |
| 56 | int ret; |
| 57 | struct lttng_ht_iter iter; |
| 58 | |
| 59 | iter.iter.node = &trace->node.node; |
| 60 | ret = lttng_ht_del(trace->session->ctf_traces_ht, &iter); |
| 61 | LTTNG_ASSERT(!ret); |
| 62 | ctf_trace_destroy(trace); |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * The caller must either: |
| 67 | * - hold the RCU read side lock, or |
| 68 | * - guarantee the existence of the object by already holding a reference to |
| 69 | * the object. |
| 70 | */ |
| 71 | bool ctf_trace_get(struct ctf_trace *trace) |
| 72 | { |
| 73 | const bool ref = urcu_ref_get_unless_zero(&trace->ref); |
| 74 | |
| 75 | if (!ref) { |
| 76 | /* |
| 77 | * The ref count is already zero. It means the object is being |
| 78 | * torn down concurently. |
| 79 | * This is only acceptable if we hold the RCU read-side lock, |
| 80 | * else it's a logic error. |
| 81 | */ |
| 82 | ASSERT_RCU_READ_LOCKED(); |
| 83 | } |
| 84 | |
| 85 | return ref; |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * Create and return an allocated ctf_trace. NULL on error. |
| 90 | * There is no "open" and "close" for a ctf_trace, but rather just a |
| 91 | * create and refcounting. Whenever all the streams belonging to a trace |
| 92 | * put their reference, its refcount drops to 0. |
| 93 | */ |
| 94 | static struct ctf_trace *ctf_trace_create(struct relay_session *session, const char *subpath) |
| 95 | { |
| 96 | struct ctf_trace *trace; |
| 97 | |
| 98 | trace = zmalloc<ctf_trace>(); |
| 99 | if (!trace) { |
| 100 | PERROR("Failed to allocate ctf_trace"); |
| 101 | goto end; |
| 102 | } |
| 103 | urcu_ref_init(&trace->ref); |
| 104 | |
| 105 | if (!session_get(session)) { |
| 106 | ERR("Failed to acquire session reference"); |
| 107 | goto error; |
| 108 | } |
| 109 | trace->session = session; |
| 110 | trace->path = strdup(subpath); |
| 111 | if (!trace->path) { |
| 112 | goto error; |
| 113 | } |
| 114 | |
| 115 | CDS_INIT_LIST_HEAD(&trace->stream_list); |
| 116 | |
| 117 | pthread_mutex_lock(&last_relay_ctf_trace_id_lock); |
| 118 | trace->id = ++last_relay_ctf_trace_id; |
| 119 | pthread_mutex_unlock(&last_relay_ctf_trace_id_lock); |
| 120 | |
| 121 | lttng_ht_node_init_str(&trace->node, trace->path); |
| 122 | trace->session = session; |
| 123 | pthread_mutex_init(&trace->lock, nullptr); |
| 124 | pthread_mutex_init(&trace->stream_list_lock, nullptr); |
| 125 | lttng_ht_add_str(session->ctf_traces_ht, &trace->node); |
| 126 | |
| 127 | DBG("Created ctf_trace %" PRIu64 " of session \"%s\" from host \"%s\" with path: %s", |
| 128 | trace->id, |
| 129 | session->session_name, |
| 130 | session->hostname, |
| 131 | subpath); |
| 132 | |
| 133 | end: |
| 134 | return trace; |
| 135 | error: |
| 136 | ctf_trace_put(trace); |
| 137 | return nullptr; |
| 138 | } |
| 139 | |
| 140 | /* |
| 141 | * Return a ctf_trace if found by id in the given hash table else NULL. |
| 142 | * Hold a reference on the ctf_trace, and must be paired with |
| 143 | * ctf_trace_put(). |
| 144 | */ |
| 145 | struct ctf_trace *ctf_trace_get_by_path_or_create(struct relay_session *session, |
| 146 | const char *subpath) |
| 147 | { |
| 148 | struct lttng_ht_node_str *node; |
| 149 | struct lttng_ht_iter iter; |
| 150 | struct ctf_trace *trace = nullptr; |
| 151 | |
| 152 | rcu_read_lock(); |
| 153 | lttng_ht_lookup(session->ctf_traces_ht, subpath, &iter); |
| 154 | node = lttng_ht_iter_get_node_str(&iter); |
| 155 | if (!node) { |
| 156 | DBG("CTF Trace path %s not found", subpath); |
| 157 | goto end; |
| 158 | } |
| 159 | trace = lttng::utils::container_of(node, &ctf_trace::node); |
| 160 | if (!ctf_trace_get(trace)) { |
| 161 | trace = nullptr; |
| 162 | } |
| 163 | end: |
| 164 | rcu_read_unlock(); |
| 165 | if (!trace) { |
| 166 | /* Try to create */ |
| 167 | trace = ctf_trace_create(session, subpath); |
| 168 | } |
| 169 | return trace; |
| 170 | } |
| 171 | |
| 172 | void ctf_trace_put(struct ctf_trace *trace) |
| 173 | { |
| 174 | rcu_read_lock(); |
| 175 | urcu_ref_put(&trace->ref, ctf_trace_release); |
| 176 | rcu_read_unlock(); |
| 177 | } |
| 178 | |
| 179 | int ctf_trace_close(struct ctf_trace *trace) |
| 180 | { |
| 181 | struct relay_stream *stream; |
| 182 | |
| 183 | rcu_read_lock(); |
| 184 | cds_list_for_each_entry_rcu(stream, &trace->stream_list, stream_node) |
| 185 | { |
| 186 | /* |
| 187 | * Close stream since the connection owning the trace is being |
| 188 | * torn down. |
| 189 | */ |
| 190 | try_stream_close(stream); |
| 191 | } |
| 192 | rcu_read_unlock(); |
| 193 | /* |
| 194 | * Since all references to the trace are held by its streams, we |
| 195 | * don't need to do any self-ref put. |
| 196 | */ |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | struct relay_viewer_stream *ctf_trace_get_viewer_metadata_stream(struct ctf_trace *trace) |
| 201 | { |
| 202 | struct relay_viewer_stream *vstream; |
| 203 | |
| 204 | rcu_read_lock(); |
| 205 | vstream = rcu_dereference(trace->viewer_metadata_stream); |
| 206 | if (!vstream) { |
| 207 | goto end; |
| 208 | } |
| 209 | if (!viewer_stream_get(vstream)) { |
| 210 | vstream = nullptr; |
| 211 | } |
| 212 | end: |
| 213 | rcu_read_unlock(); |
| 214 | return vstream; |
| 215 | } |