sessiond: snapshot: set trace chunk to NULL before closing it
[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c
index 5a122d8d3c8dcf7e7f361b34f69f46c4680c0d22..53850f74aae784b97a668f30c429c92cca8858be 100644 (file)
@@ -998,6 +998,8 @@ static enum lttng_error_code create_connect_relayd(struct lttng_uri *uri,
 
        /* Create socket for control stream. */
        if (uri->stype == LTTNG_STREAM_CONTROL) {
+               uint64_t result_flags;
+
                DBG3("Creating relayd stream socket from URI");
 
                /* Check relayd version */
@@ -1012,6 +1014,16 @@ static enum lttng_error_code create_connect_relayd(struct lttng_uri *uri,
                }
                consumer->relay_major_version = rsock->major;
                consumer->relay_minor_version = rsock->minor;
+               ret = relayd_get_configuration(rsock, 0,
+                               &result_flags);
+               if (ret < 0) {
+                       ERR("Unable to get relayd configuration");
+                       status = LTTNG_ERR_RELAYD_CONNECT_FAIL;
+                       goto close_sock;
+               }
+               if (result_flags & LTTCOMM_RELAYD_CONFIGURATION_FLAG_CLEAR_ALLOWED) {
+                       consumer->relay_allows_clear = true;
+               }
        } else if (uri->stype == LTTNG_STREAM_DATA) {
                DBG3("Creating relayd data socket from URI");
        } else {
@@ -1185,6 +1197,7 @@ int cmd_setup_relayd(struct ltt_session *session)
 
        DBG("Setting relayd for session %s", session->name);
 
+       rcu_read_lock();
        if (session->current_trace_chunk) {
                enum lttng_trace_chunk_status status = lttng_trace_chunk_get_id(
                                session->current_trace_chunk, &current_chunk_id.value);
@@ -1198,8 +1211,6 @@ int cmd_setup_relayd(struct ltt_session *session)
                }
        }
 
-       rcu_read_lock();
-
        if (usess && usess->consumer && usess->consumer->type == CONSUMER_DST_NET
                        && usess->consumer->enabled) {
                /* For each consumer socket, send relayd sockets */
@@ -1225,6 +1236,8 @@ int cmd_setup_relayd(struct ltt_session *session)
                        usess->consumer->relay_major_version;
                session->consumer->relay_minor_version =
                        usess->consumer->relay_minor_version;
+               session->consumer->relay_allows_clear =
+                       usess->consumer->relay_allows_clear;
        }
 
        if (ksess && ksess->consumer && ksess->consumer->type == CONSUMER_DST_NET
@@ -1251,6 +1264,8 @@ int cmd_setup_relayd(struct ltt_session *session)
                        ksess->consumer->relay_major_version;
                session->consumer->relay_minor_version =
                        ksess->consumer->relay_minor_version;
+               session->consumer->relay_allows_clear =
+                       ksess->consumer->relay_allows_clear;
        }
 
 error:
@@ -1261,7 +1276,7 @@ error:
 /*
  * Start a kernel session by opening all necessary streams.
  */
-static int start_kernel_session(struct ltt_kernel_session *ksess)
+int start_kernel_session(struct ltt_kernel_session *ksess)
 {
        int ret;
        struct ltt_kernel_channel *kchan;
@@ -1323,6 +1338,53 @@ error:
        return ret;
 }
 
+int stop_kernel_session(struct ltt_kernel_session *ksess)
+{
+       struct ltt_kernel_channel *kchan;
+       bool error_occurred = false;
+       int ret;
+
+       if (!ksess || !ksess->active) {
+               return LTTNG_OK;
+       }
+       DBG("Stopping kernel tracing");
+
+       ret = kernel_stop_session(ksess);
+       if (ret < 0) {
+               ret = LTTNG_ERR_KERN_STOP_FAIL;
+               goto error;
+       }
+
+       kernel_wait_quiescent();
+
+       /* Flush metadata after stopping (if exists) */
+       if (ksess->metadata_stream_fd >= 0) {
+               ret = kernel_metadata_flush_buffer(ksess->metadata_stream_fd);
+               if (ret < 0) {
+                       ERR("Kernel metadata flush failed");
+                       error_occurred = true;
+               }
+       }
+
+       /* Flush all buffers after stopping */
+       cds_list_for_each_entry(kchan, &ksess->channel_list.head, list) {
+               ret = kernel_flush_buffer(kchan);
+               if (ret < 0) {
+                       ERR("Kernel flush buffer error");
+                       error_occurred = true;
+               }
+       }
+
+       ksess->active = 0;
+       if (error_occurred) {
+               ret = LTTNG_ERR_UNK;
+       } else {
+               ret = LTTNG_OK;
+       }
+error:
+       return ret;
+}
+
 /*
  * Command LTTNG_DISABLE_CHANNEL processed by the client thread.
  */
@@ -2574,6 +2636,8 @@ int cmd_start_trace(struct ltt_session *session)
        struct ltt_ust_session *usess;
        const bool session_rotated_after_last_stop =
                        session->rotated_after_last_stop;
+       const bool session_cleared_after_last_stop =
+                       session->cleared_after_last_stop;
 
        assert(session);
 
@@ -2620,6 +2684,7 @@ int cmd_start_trace(struct ltt_session *session)
 
        session->active = 1;
        session->rotated_after_last_stop = false;
+       session->cleared_after_last_stop = false;
        if (session->output_traces && !session->current_trace_chunk) {
                if (!session->has_been_started) {
                        struct lttng_trace_chunk *trace_chunk;
@@ -2653,7 +2718,8 @@ int cmd_start_trace(struct ltt_session *session)
                         * was produced as the session was stopped, so the
                         * rotation should happen on reception of the command.
                         */
-                       ret = cmd_rotate_session(session, NULL, true);
+                       ret = cmd_rotate_session(session, NULL, true,
+                                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION);
                        if (ret != LTTNG_OK) {
                                goto error;
                        }
@@ -2707,6 +2773,8 @@ error:
                /* Restore initial state on error. */
                session->rotated_after_last_stop =
                                session_rotated_after_last_stop;
+               session->cleared_after_last_stop =
+                               session_cleared_after_last_stop;
        }
        return ret;
 }
@@ -2717,14 +2785,12 @@ error:
 int cmd_stop_trace(struct ltt_session *session)
 {
        int ret;
-       struct ltt_kernel_channel *kchan;
        struct ltt_kernel_session *ksession;
        struct ltt_ust_session *usess;
-       bool error_occurred = false;
 
        assert(session);
 
-       DBG("Begin stop session %s (id %" PRIu64 ")", session->name, session->id);
+       DBG("Begin stop session \"%s\" (id %" PRIu64 ")", session->name, session->id);
        /* Short cut */
        ksession = session->kernel_session;
        usess = session->ust_session;
@@ -2735,39 +2801,9 @@ int cmd_stop_trace(struct ltt_session *session)
                goto error;
        }
 
-       /* Kernel tracer */
-       if (ksession && ksession->active) {
-               DBG("Stop kernel tracing");
-
-               ret = kernel_stop_session(ksession);
-               if (ret < 0) {
-                       ret = LTTNG_ERR_KERN_STOP_FAIL;
-                       goto error;
-               }
-
-               kernel_wait_quiescent();
-
-               /* Flush metadata after stopping (if exists) */
-               if (ksession->metadata_stream_fd >= 0) {
-                       ret = kernel_metadata_flush_buffer(ksession->metadata_stream_fd);
-                       if (ret < 0) {
-                               ERR("Kernel metadata flush failed");
-                               error_occurred = true;
-                       }
-               }
-
-               /* Flush all buffers after stopping */
-               cds_list_for_each_entry(kchan, &ksession->channel_list.head, list) {
-                       ret = kernel_flush_buffer(kchan);
-                       if (ret < 0) {
-                               ERR("Kernel flush buffer error");
-                               error_occurred = true;
-                       }
-               }
-
-               ksession->active = 0;
-               DBG("Kernel session stopped %s (id %" PRIu64 ")", session->name,
-                               session->id);
+       ret = stop_kernel_session(ksession);
+       if (ret != LTTNG_OK) {
+               goto error;
        }
 
        if (usess && usess->active) {
@@ -2778,9 +2814,11 @@ int cmd_stop_trace(struct ltt_session *session)
                }
        }
 
+       DBG("Completed stop session \"%s\" (id %" PRIu64 ")", session->name,
+                       session->id);
        /* Flag inactive after a successful stop. */
        session->active = 0;
-       ret = !error_occurred ? LTTNG_OK : LTTNG_ERR_UNK;
+       ret = LTTNG_OK;
 
 error:
        return ret;
@@ -3290,14 +3328,13 @@ int cmd_destroy_session(struct ltt_session *session,
                session->rotate_size = 0;
        }
 
-       if (session->most_recent_chunk_id.is_set &&
-                       session->most_recent_chunk_id.value != 0 &&
-                       session->current_trace_chunk && session->output_traces) {
+       if (session->rotated && session->current_trace_chunk && session->output_traces) {
                /*
                 * Perform a last rotation on destruction if rotations have
                 * occurred during the session's lifetime.
                 */
-               ret = cmd_rotate_session(session, NULL, false);
+               ret = cmd_rotate_session(session, NULL, false,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
                if (ret != LTTNG_OK) {
                        ERR("Failed to perform an implicit rotation as part of the destruction of session \"%s\": %s",
                                        session->name, lttng_strerror(-ret));
@@ -3316,7 +3353,8 @@ int cmd_destroy_session(struct ltt_session *session,
                 * emitted and no renaming of the current trace chunk takes
                 * place.
                 */
-               ret = cmd_rotate_session(session, NULL, true);
+               ret = cmd_rotate_session(session, NULL, true,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION);
                if (ret != LTTNG_OK) {
                        ERR("Failed to perform a quiet rotation as part of the destruction of session \"%s\": %s",
                                        session->name, lttng_strerror(-ret));
@@ -4675,8 +4713,14 @@ enum lttng_error_code snapshot_record(struct ltt_session *session,
                }
        }
 
-       if (session_close_trace_chunk(
-                           session, session->current_trace_chunk, NULL, NULL)) {
+       if (session_set_trace_chunk(session, NULL, &snapshot_trace_chunk)) {
+               ERR("Failed to release the current trace chunk of session \"%s\"",
+                               session->name);
+               ret_code = LTTNG_ERR_UNK;
+       }
+
+       if (session_close_trace_chunk(session, snapshot_trace_chunk,
+                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION, NULL)) {
                /*
                 * Don't goto end; make sure the chunk is closed for the session
                 * to allow future snapshots.
@@ -4685,11 +4729,6 @@ enum lttng_error_code snapshot_record(struct ltt_session *session,
                                session->name);
                ret_code = LTTNG_ERR_CLOSE_TRACE_CHUNK_FAIL_CONSUMER;
        }
-       if (session_set_trace_chunk(session, NULL, NULL)) {
-               ERR("Failed to release the current trace chunk of session \"%s\"",
-                               session->name);
-               ret_code = LTTNG_ERR_UNK;
-       }
 error:
        if (original_ust_consumer_output) {
                session->ust_session->consumer = original_ust_consumer_output;
@@ -4870,7 +4909,8 @@ int cmd_set_session_shm_path(struct ltt_session *session,
  */
 int cmd_rotate_session(struct ltt_session *session,
                struct lttng_rotate_session_return *rotate_return,
-               bool quiet_rotation)
+               bool quiet_rotation,
+               enum lttng_trace_chunk_command_type command)
 {
        int ret;
        uint64_t ongoing_rotation_chunk_id;
@@ -4908,6 +4948,12 @@ int cmd_rotate_session(struct ltt_session *session,
                goto end;
        }
 
+       /* Unsupported feature in lttng-modules before 2.8 (lack of sequence number). */
+       if (session->kernel_session && !kernel_supports_ring_buffer_packet_sequence_number()) {
+               cmd_ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE_KERNEL;
+               goto end;
+       }
+
        if (session->rotation_state == LTTNG_ROTATION_STATE_ONGOING) {
                DBG("Refusing to launch a rotation; a rotation is already in progress for session %s",
                                session->name);
@@ -4926,7 +4972,16 @@ int cmd_rotate_session(struct ltt_session *session,
                goto end;
        }
 
-       session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+       /*
+        * After a stop followed by a clear, disallow following rotations a they would
+        * generate empty chunks.
+        */
+       if (session->cleared_after_last_stop) {
+               DBG("Session \"%s\" was already cleared after stop, refusing rotation",
+                               session->name);
+               cmd_ret = LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR;
+               goto end;
+       }
 
        if (session->active) {
                new_trace_chunk = session_create_new_trace_chunk(session, NULL,
@@ -4951,11 +5006,6 @@ int cmd_rotate_session(struct ltt_session *session,
                goto error;
        }
 
-       assert(chunk_being_archived);
-       chunk_status = lttng_trace_chunk_get_id(chunk_being_archived,
-                       &ongoing_rotation_chunk_id);
-       assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
-
        if (session->kernel_session) {
                cmd_ret = kernel_rotate_session(session);
                if (cmd_ret != LTTNG_OK) {
@@ -4971,12 +5021,28 @@ int cmd_rotate_session(struct ltt_session *session,
                }
        }
 
+       if (!session->active) {
+               session->rotated_after_last_stop = true;
+       }
+
+       if (!chunk_being_archived) {
+               DBG("Rotating session \"%s\" from a \"NULL\" trace chunk to a new trace chunk, skipping completion check",
+                               session->name);
+               if (failed_to_rotate) {
+                       cmd_ret = rotation_fail_code;
+                       goto error;
+               }
+               cmd_ret = LTTNG_OK;
+               goto end;
+       }
+
+       session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+       chunk_status = lttng_trace_chunk_get_id(chunk_being_archived,
+                       &ongoing_rotation_chunk_id);
+       assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
+
        ret = session_close_trace_chunk(session, chunk_being_archived,
-                       quiet_rotation ?
-                                       NULL :
-                                       &((enum lttng_trace_chunk_command_type){
-                                                       LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED}),
-                       session->last_chunk_path);
+               command, session->last_chunk_path);
        if (ret) {
                cmd_ret = LTTNG_ERR_CLOSE_TRACE_CHUNK_FAIL_CONSUMER;
                goto error;
@@ -4995,10 +5061,6 @@ int cmd_rotate_session(struct ltt_session *session,
                goto error;
        }
 
-       if (!session->active) {
-               session->rotated_after_last_stop = true;
-       }
-
        if (rotate_return) {
                rotate_return->rotation_id = ongoing_rotation_chunk_id;
        }
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