Fix: possible null dereference
[lttng-tools.git] / src / bin / lttng-sessiond / session.c
index 3a537e49e2179357298cb43813dfa17a6f63927d..03bec43fd9284009fbdb7e07e85519d8116f7746 100644 (file)
@@ -1,18 +1,8 @@
 /*
- * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -46,6 +36,11 @@ struct ltt_session_destroy_notifier_element {
        void *user_data;
 };
 
+struct ltt_session_clear_notifier_element {
+       ltt_session_clear_notifier notifier;
+       void *user_data;
+};
+
 /*
  * NOTES:
  *
@@ -584,6 +579,7 @@ struct lttng_trace_chunk *session_create_new_trace_chunk(
        };
        uint64_t next_chunk_id;
        const struct consumer_output *output;
+       const char *new_path;
 
        if (consumer_output_override) {
                output = consumer_output_override;
@@ -607,8 +603,26 @@ struct lttng_trace_chunk *session_create_new_trace_chunk(
        next_chunk_id = session->most_recent_chunk_id.is_set ?
                        session->most_recent_chunk_id.value + 1 : 0;
 
+       if (session->current_trace_chunk &&
+                       !lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
+               chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
+                                       DEFAULT_CHUNK_TMP_OLD_DIRECTORY);
+               if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+                       goto error;
+               }
+       }
+       if (!session->current_trace_chunk) {
+               if (!session->rotated) {
+                       new_path = "";
+               } else {
+                       new_path = NULL;
+               }
+       } else {
+               new_path = DEFAULT_CHUNK_TMP_NEW_DIRECTORY;
+       }
+
        trace_chunk = lttng_trace_chunk_create(next_chunk_id,
-                       chunk_creation_ts);
+                       chunk_creation_ts, new_path);
        if (!trace_chunk) {
                goto error;
        }
@@ -673,6 +687,7 @@ int session_close_trace_chunk(struct ltt_session *session,
        struct consumer_socket *socket;
        enum lttng_trace_chunk_status chunk_status;
        const time_t chunk_close_timestamp = time(NULL);
+       const char *new_path;
 
        chunk_status = lttng_trace_chunk_set_close_command(
                        trace_chunk, close_command);
@@ -687,6 +702,44 @@ int session_close_trace_chunk(struct ltt_session *session,
                ret = -1;
                goto end;
        }
+
+       if (close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE && !session->rotated) {
+               /* New chunk stays in session output directory. */
+               new_path = "";
+       } else {
+               /* Use chunk name for new chunk. */
+               new_path = NULL;
+       }
+       if (session->current_trace_chunk &&
+                       !lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
+               /* Rename new chunk path. */
+               chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
+                                       new_path);
+               if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+                       ret = -1;
+                       goto end;
+               }
+       }
+       if (!lttng_trace_chunk_get_name_overridden(trace_chunk) &&
+                       close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION) {
+               const char *old_path;
+
+               if (!session->rotated) {
+                       old_path = "";
+               } else {
+                       old_path = NULL;
+               }
+               /* We need to move back the .tmp_old_chunk to its rightful place. */
+               chunk_status = lttng_trace_chunk_rename_path(trace_chunk,
+                                       old_path);
+               if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+                       ret = -1;
+                       goto end;
+               }
+       }
+       if (close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED) {
+               session->rotated = true;
+       }
        chunk_status = lttng_trace_chunk_set_close_timestamp(trace_chunk,
                        chunk_close_timestamp);
        if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
@@ -769,6 +822,25 @@ void session_notify_destruction(const struct ltt_session *session)
        }
 }
 
+/*
+ * Fire each clear notifier once, and remove them from the array.
+ */
+void session_notify_clear(struct ltt_session *session)
+{
+       size_t i;
+       const size_t count = lttng_dynamic_array_get_count(
+                       &session->clear_notifiers);
+
+       for (i = 0; i < count; i++) {
+               const struct ltt_session_clear_notifier_element *element =
+                       lttng_dynamic_array_get_element(
+                                       &session->clear_notifiers, i);
+
+               element->notifier(session, element->user_data);
+       }
+       lttng_dynamic_array_clear(&session->clear_notifiers);
+}
+
 static
 void session_release(struct urcu_ref *ref)
 {
@@ -831,6 +903,7 @@ void session_release(struct urcu_ref *ref)
                session->ust_session = NULL;
        }
        lttng_dynamic_array_reset(&session->destroy_notifiers);
+       lttng_dynamic_array_reset(&session->clear_notifiers);
        free(session->last_archived_chunk_name);
        free(session->base_path);
        free(session);
@@ -899,6 +972,18 @@ int session_add_destroy_notifier(struct ltt_session *session,
                        &element);
 }
 
+int session_add_clear_notifier(struct ltt_session *session,
+               ltt_session_clear_notifier notifier, void *user_data)
+{
+       const struct ltt_session_clear_notifier_element element = {
+               .notifier = notifier,
+               .user_data = user_data
+       };
+
+       return lttng_dynamic_array_add_element(&session->clear_notifiers,
+                       &element);
+}
+
 /*
  * Return a ltt_session structure ptr that matches name. If no session found,
  * NULL is returned. This must be called with the session list lock held using
@@ -990,6 +1075,9 @@ enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
        lttng_dynamic_array_init(&new_session->destroy_notifiers,
                        sizeof(struct ltt_session_destroy_notifier_element),
                        NULL);
+       lttng_dynamic_array_init(&new_session->clear_notifiers,
+                       sizeof(struct ltt_session_clear_notifier_element),
+                       NULL);
        urcu_ref_init(&new_session->ref);
        pthread_mutex_init(&new_session->lock, NULL);
 
@@ -1184,6 +1272,11 @@ int session_reset_rotation_state(struct ltt_session *session,
                                chunk_id);
                lttng_trace_chunk_put(session->chunk_being_archived);
                session->chunk_being_archived = NULL;
+               /*
+                * Fire the clear reply notifiers if we are completing a clear
+                * rotation.
+                */
+               session_notify_clear(session);
        }
        return ret;
 }
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