Fix: sessiond: no rotation performed from null chunk to new chunk
[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c
index a17cc678ecab2363a95166b82f1c794a15c8ff96..5a122d8d3c8dcf7e7f361b34f69f46c4680c0d22 100644 (file)
@@ -2572,6 +2572,8 @@ int cmd_start_trace(struct ltt_session *session)
        unsigned long nb_chan = 0;
        struct ltt_kernel_session *ksession;
        struct ltt_ust_session *usess;
+       const bool session_rotated_after_last_stop =
+                       session->rotated_after_last_stop;
 
        assert(session);
 
@@ -2585,6 +2587,22 @@ int cmd_start_trace(struct ltt_session *session)
                goto error;
        }
 
+       if (session->rotation_state == LTTNG_ROTATION_STATE_ONGOING &&
+                       !session->current_trace_chunk) {
+               /*
+                * A rotation was launched while the session was stopped and
+                * it has not been completed yet. It is not possible to start
+                * the session since starting the session here would require a
+                * rotation from "NULL" to a new trace chunk. That rotation
+                * would overlap with the ongoing rotation, which is not
+                * supported.
+                */
+               WARN("Refusing to start session \"%s\" as a rotation launched after the last \"stop\" is still ongoing",
+                               session->name);
+               ret = LTTNG_ERR_ROTATION_PENDING;
+               goto error;
+       }
+
        /*
         * Starting a session without channel is useless since after that it's not
         * possible to enable channel thus inform the client.
@@ -2600,21 +2618,45 @@ int cmd_start_trace(struct ltt_session *session)
                goto error;
        }
 
+       session->active = 1;
+       session->rotated_after_last_stop = false;
        if (session->output_traces && !session->current_trace_chunk) {
-               struct lttng_trace_chunk *trace_chunk;
+               if (!session->has_been_started) {
+                       struct lttng_trace_chunk *trace_chunk;
 
-               trace_chunk = session_create_new_trace_chunk(
-                               session, NULL, NULL, NULL);
-               if (!trace_chunk) {
-                       ret = LTTNG_ERR_CREATE_DIR_FAIL;
-                       goto error;
-               }
-               assert(!session->current_trace_chunk);
-               ret = session_set_trace_chunk(session, trace_chunk, NULL);
-               lttng_trace_chunk_put(trace_chunk);
-               if (ret) {
-                       ret = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
-                       goto error;
+                       DBG("Creating initial trace chunk of session \"%s\"",
+                                       session->name);
+                       trace_chunk = session_create_new_trace_chunk(
+                                       session, NULL, NULL, NULL);
+                       if (!trace_chunk) {
+                               ret = LTTNG_ERR_CREATE_DIR_FAIL;
+                               goto error;
+                       }
+                       assert(!session->current_trace_chunk);
+                       ret = session_set_trace_chunk(session, trace_chunk,
+                                       NULL);
+                       lttng_trace_chunk_put(trace_chunk);
+                       if (ret) {
+                               ret = LTTNG_ERR_CREATE_TRACE_CHUNK_FAIL_CONSUMER;
+                               goto error;
+                       }
+               } else {
+                       DBG("Rotating session \"%s\" from its current \"NULL\" trace chunk to a new chunk",
+                                       session->name);
+                       /*
+                        * Rotate existing streams into the new chunk.
+                        * This is a "quiet" rotation has no client has
+                        * explicitly requested this operation.
+                        *
+                        * There is also no need to wait for the rotation
+                        * to complete as it will happen immediately. No data
+                        * was produced as the session was stopped, so the
+                        * rotation should happen on reception of the command.
+                        */
+                       ret = cmd_rotate_session(session, NULL, true);
+                       if (ret != LTTNG_OK) {
+                               goto error;
+                       }
                }
        }
 
@@ -2637,10 +2679,6 @@ int cmd_start_trace(struct ltt_session *session)
                }
        }
 
-       /* Flag this after a successful start. */
-       session->has_been_started = 1;
-       session->active = 1;
-
        /*
         * Clear the flag that indicates that a rotation was done while the
         * session was stopped.
@@ -2661,6 +2699,15 @@ int cmd_start_trace(struct ltt_session *session)
        ret = LTTNG_OK;
 
 error:
+       if (ret == LTTNG_OK) {
+               /* Flag this after a successful start. */
+               session->has_been_started |= 1;
+       } else {
+               session->active = 0;
+               /* Restore initial state on error. */
+               session->rotated_after_last_stop =
+                               session_rotated_after_last_stop;
+       }
        return ret;
 }
 
@@ -2739,6 +2786,45 @@ error:
        return ret;
 }
 
+/*
+ * Set the base_path of the session only if subdir of a control uris is set.
+ * Return LTTNG_OK on success, otherwise LTTNG_ERR_*.
+ */
+static int set_session_base_path_from_uris(struct ltt_session *session,
+               size_t nb_uri,
+               struct lttng_uri *uris)
+{
+       int ret;
+       size_t i;
+
+       for (i = 0; i < nb_uri; i++) {
+               if (uris[i].stype != LTTNG_STREAM_CONTROL ||
+                               uris[i].subdir[0] == '\0') {
+                       /* Not interested in these URIs */
+                       continue;
+               }
+
+               if (session->base_path != NULL) {
+                       free(session->base_path);
+                       session->base_path = NULL;
+               }
+
+               /* Set session base_path */
+               session->base_path = strdup(uris[i].subdir);
+               if (!session->base_path) {
+                       PERROR("Failed to copy base path \"%s\" to session \"%s\"",
+                                       uris[i].subdir, session->name);
+                       ret = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+               DBG2("Setting base path \"%s\" for session \"%s\"",
+                               session->base_path, session->name);
+       }
+       ret = LTTNG_OK;
+error:
+       return ret;
+}
+
 /*
  * Command LTTNG_SET_CONSUMER_URI processed by the client thread.
  */
@@ -2759,11 +2845,20 @@ int cmd_set_consumer_uri(struct ltt_session *session, size_t nb_uri,
                goto error;
        }
 
+       /*
+        * Set the session base path if any. This is done inside
+        * cmd_set_consumer_uri to preserve backward compatibility of the
+        * previous session creation api vs the session descriptor api.
+        */
+       ret = set_session_base_path_from_uris(session, nb_uri, uris);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
+
        /* Set the "global" consumer URIs */
        for (i = 0; i < nb_uri; i++) {
-               ret = add_uri_to_consumer(session,
-                               session->consumer,
-                               &uris[i], LTTNG_DOMAIN_NONE);
+               ret = add_uri_to_consumer(session, session->consumer, &uris[i],
+                               LTTNG_DOMAIN_NONE);
                if (ret != LTTNG_OK) {
                        goto error;
                }
@@ -2894,7 +2989,6 @@ enum lttng_error_code cmd_create_session_from_descriptor(
        const char *session_name;
        struct ltt_session *new_session = NULL;
        enum lttng_session_descriptor_status descriptor_status;
-       const char *base_path;
 
        session_lock_list();
        if (home_path) {
@@ -2917,13 +3011,9 @@ enum lttng_error_code cmd_create_session_from_descriptor(
                ret_code = LTTNG_ERR_INVALID;
                goto end;
        }
-       ret = lttng_session_descriptor_get_base_path(descriptor, &base_path);
-       if (ret) {
-               ret_code = LTTNG_ERR_INVALID;
-               goto end;
-       }
+
        ret_code = session_create(session_name, creds->uid, creds->gid,
-                       base_path, &new_session);
+                       &new_session);
        if (ret_code != LTTNG_OK) {
                goto end;
        }
@@ -4788,6 +4878,8 @@ int cmd_rotate_session(struct ltt_session *session,
        struct lttng_trace_chunk *chunk_being_archived = NULL;
        struct lttng_trace_chunk *new_trace_chunk = NULL;
        enum lttng_trace_chunk_status chunk_status;
+       bool failed_to_rotate = false;
+       enum lttng_error_code rotation_fail_code = LTTNG_OK;
 
        assert(session);
 
@@ -4845,7 +4937,13 @@ int cmd_rotate_session(struct ltt_session *session,
                }
         }
 
-        /* The current trace chunk becomes the chunk being archived. */
+       /*
+        * The current trace chunk becomes the chunk being archived.
+        *
+        * After this point, "chunk_being_archived" must absolutely
+        * be closed on the consumer(s), otherwise it will never be
+        * cleaned-up, which will result in a leak.
+        */
        ret = session_set_trace_chunk(session, new_trace_chunk,
                        &chunk_being_archived);
        if (ret) {
@@ -4861,13 +4959,15 @@ int cmd_rotate_session(struct ltt_session *session,
        if (session->kernel_session) {
                cmd_ret = kernel_rotate_session(session);
                if (cmd_ret != LTTNG_OK) {
-                       goto error;
+                       failed_to_rotate = true;
+                       rotation_fail_code = cmd_ret;
                }
        }
        if (session->ust_session) {
                cmd_ret = ust_app_rotate_session(session);
                if (cmd_ret != LTTNG_OK) {
-                       goto error;
+                       failed_to_rotate = true;
+                       rotation_fail_code = cmd_ret;
                }
        }
 
@@ -4882,6 +4982,11 @@ int cmd_rotate_session(struct ltt_session *session,
                goto error;
        }
 
+       if (failed_to_rotate) {
+               cmd_ret = rotation_fail_code;
+               goto error;
+       }
+
        session->quiet_rotation = quiet_rotation;
        ret = timer_session_rotation_pending_check_start(session,
                        DEFAULT_ROTATE_PENDING_TIMER);
@@ -4968,7 +5073,7 @@ int cmd_rotate_get_info(struct ltt_session *session,
 
        switch (rotation_state) {
        case LTTNG_ROTATION_STATE_NO_ROTATION:
-               DBG("Reporting that no rotation has occured within the lifetime of session \"%s\"",
+               DBG("Reporting that no rotation has occurred within the lifetime of session \"%s\"",
                                session->name);
                goto end;
        case LTTNG_ROTATION_STATE_EXPIRED:
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