Generate session name and default output on sessiond's end
[lttng-tools.git] / src / bin / lttng-sessiond / session.c
index 5e6488e4f28c67a98fc3bdf9cb1459fedde50fc3..491de61759825f0485326cae5b2d7e72db72c6ad 100644 (file)
@@ -467,6 +467,9 @@ bool session_get(struct ltt_session *session)
  */
 void session_put(struct ltt_session *session)
 {
+       if (!session) {
+               return;
+       }
        /*
         * The session list lock must be held as any session_put()
         * may cause the removal of the session from the session_list.
@@ -554,77 +557,144 @@ end:
 }
 
 /*
- * Create a brand new session and add it to the session list.
+ * Create a new session and add it to the session list.
+ * Session list lock must be held by the caller.
  */
-int session_create(char *name, uid_t uid, gid_t gid)
+enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
+               struct ltt_session **out_session)
 {
        int ret;
-       struct ltt_session *new_session;
+       enum lttng_error_code ret_code;
+       struct ltt_session *new_session = NULL;
 
-       /* Allocate session data structure */
+       ASSERT_LOCKED(ltt_session_list.lock);
+       if (name) {
+               struct ltt_session *clashing_session;
+
+               clashing_session = session_find_by_name(name);
+               if (clashing_session) {
+                       session_put(clashing_session);
+                       ret_code = LTTNG_ERR_EXIST_SESS;
+                       goto error;
+               }
+       }
        new_session = zmalloc(sizeof(struct ltt_session));
-       if (new_session == NULL) {
-               PERROR("zmalloc");
-               ret = LTTNG_ERR_FATAL;
-               goto error_malloc;
+       if (!new_session) {
+               PERROR("Failed to allocate an ltt_session structure");
+               ret_code = LTTNG_ERR_NOMEM;
+               goto error;
        }
 
        urcu_ref_init(&new_session->ref);
+       pthread_mutex_init(&new_session->lock, NULL);
 
-       /* Define session name */
-       if (name != NULL) {
-               if (snprintf(new_session->name, NAME_MAX, "%s", name) < 0) {
-                       ret = LTTNG_ERR_FATAL;
-                       goto error_asprintf;
-               }
-       } else {
-               ERR("No session name given");
-               ret = LTTNG_ERR_FATAL;
+       new_session->creation_time = time(NULL);
+       if (new_session->creation_time == (time_t) -1) {
+               PERROR("Failed to sample session creation time");
+               ret_code = LTTNG_ERR_SESSION_FAIL;
                goto error;
        }
 
-       ret = validate_name(name);
-       if (ret < 0) {
-               ret = LTTNG_ERR_SESSION_INVALID_CHAR;
+       /* Create default consumer output. */
+       new_session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
+       if (new_session->consumer == NULL) {
+               ret_code = LTTNG_ERR_NOMEM;
                goto error;
        }
 
+       if (name) {
+               ret = lttng_strncpy(new_session->name, name, sizeof(new_session->name));
+               if (ret) {
+                       ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
+                       goto error;
+               }
+               ret = validate_name(name);
+               if (ret < 0) {
+                       ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
+                       goto error;
+               }
+       } else {
+               int i = 0;
+               bool found_name = false;
+               char datetime[16];
+               struct tm *timeinfo;
+
+               timeinfo = localtime(&new_session->creation_time);
+               if (!timeinfo) {
+                       ret_code = LTTNG_ERR_SESSION_FAIL;
+                       goto error;
+               }
+               strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
+               for (i = 0; i < INT_MAX; i++) {
+                       struct ltt_session *clashing_session;
+
+                       if (i == 0) {
+                               ret = snprintf(new_session->name,
+                                               sizeof(new_session->name),
+                                               "%s-%s",
+                                               DEFAULT_SESSION_NAME,
+                                               datetime);
+                       } else {
+                               ret = snprintf(new_session->name,
+                                               sizeof(new_session->name),
+                                               "%s%d-%s",
+                                               DEFAULT_SESSION_NAME, i,
+                                               datetime);
+                       }
+                       if (ret == -1 || ret >= sizeof(new_session->name)) {
+                               /*
+                                * Null-terminate in case the name is used
+                                * in logging statements.
+                                */
+                               new_session->name[sizeof(new_session->name) - 1] = '\0';
+                               ret_code = LTTNG_ERR_SESSION_FAIL;
+                               goto error;
+                       }
+
+                       clashing_session =
+                                       session_find_by_name(new_session->name);
+                       session_put(clashing_session);
+                       if (!clashing_session) {
+                               found_name = true;
+                               break;
+                       }
+               }
+               if (found_name) {
+                       DBG("Generated session name \"%s\"", new_session->name);
+                       new_session->has_auto_generated_name = true;
+               } else {
+                       ERR("Failed to auto-generate a session name");
+                       ret_code = LTTNG_ERR_SESSION_FAIL;
+                       goto error;
+               }
+       }
+
        ret = gethostname(new_session->hostname, sizeof(new_session->hostname));
        if (ret < 0) {
                if (errno == ENAMETOOLONG) {
                        new_session->hostname[sizeof(new_session->hostname) - 1] = '\0';
+                       ERR("Hostname exceeds the maximal permitted length and has been truncated to %s",
+                                       new_session->hostname);
                } else {
-                       ret = LTTNG_ERR_FATAL;
+                       ret_code = LTTNG_ERR_SESSION_FAIL;
                        goto error;
                }
        }
 
-       /* Init kernel session */
-       new_session->kernel_session = NULL;
-       new_session->ust_session = NULL;
-
-       /* Init lock */
-       pthread_mutex_init(&new_session->lock, NULL);
-
        new_session->uid = uid;
        new_session->gid = gid;
 
        ret = snapshot_init(&new_session->snapshot);
        if (ret < 0) {
-               ret = LTTNG_ERR_NOMEM;
+               ret_code = LTTNG_ERR_NOMEM;
                goto error;
        }
 
-       new_session->rotation_pending_local = false;
-       new_session->rotation_pending_relay = false;
        new_session->rotation_state = LTTNG_ROTATION_STATE_NO_ROTATION;
 
-       new_session->rotation_pending_check_timer_enabled = false;
-       new_session->rotation_schedule_timer_enabled = false;
-
-       /* Add new session to the session list */
-       session_lock_list();
+       /* Add new session to the session list. */
        new_session->id = add_session_list(new_session);
+
        /*
         * Add the new session to the ltt_sessions_ht_by_id.
         * No ownership is taken by the hash table; it is merely
@@ -633,25 +703,25 @@ int session_create(char *name, uid_t uid, gid_t gid)
         */
        add_session_ht(new_session);
        new_session->published = true;
-       session_unlock_list();
 
        /*
-        * Consumer is let to NULL since the create_session_uri command will set it
-        * up and, if valid, assign it to the session.
+        * Consumer is left to NULL since the create_session_uri command will
+        * set it up and, if valid, assign it to the session.
         */
-       DBG("Tracing session %s created with ID %" PRIu64 " by UID %d GID %d",
-                       name, new_session->id, new_session->uid, new_session->gid);
-
-       return LTTNG_OK;
-
+       DBG("Tracing session %s created with ID %" PRIu64 " by uid = %d, gid = %d",
+                       new_session->name, new_session->id, new_session->uid,
+                       new_session->gid);
+       ret_code = LTTNG_OK;
+end:
+       if (new_session) {
+               (void) session_get(new_session);
+               *out_session = new_session;
+       }
+       return ret_code;
 error:
-error_asprintf:
-       session_lock_list();
        session_put(new_session);
-       session_unlock_list();
-
-error_malloc:
-       return ret;
+       new_session = NULL;
+       goto end;
 }
 
 /*
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