sessiond: enforce user-exclusive session access in session_access_ok

[lttng-tools.git] / src / bin / lttng-sessiond / session.h

diff --git a/src/bin/lttng-sessiond/session.h b/src/bin/lttng-sessiond/session.h
index 204701429ded69ba43c77b8917306bc347330172..e6ed40cc2927f624ce3255492a91e129edcb5a8c 100644 (file)
--- a/src/bin/lttng-sessiond/session.h
+++ b/src/bin/lttng-sessiond/session.h
@@ -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.
  */
 
 #ifndef _LTT_SESSION_H
@@ -36,6 +26,8 @@ struct ltt_ust_session;
 
 typedef void (*ltt_session_destroy_notifier)(const struct ltt_session *session,
                void *user_data);
+typedef void (*ltt_session_clear_notifier)(const struct ltt_session *session,
+               void *user_data);
 
 /*
  * Tracing session list
@@ -77,6 +69,8 @@ struct ltt_session {
        bool has_auto_generated_name;
        bool name_contains_creation_time;
        char hostname[HOST_NAME_MAX]; /* Local hostname. */
+       /* Path of the last closed chunk. */
+       char last_chunk_path[LTTNG_PATH_MAX];
        time_t creation_time;
        struct ltt_kernel_session *kernel_session;
        struct ltt_ust_session *ust_session;
@@ -168,9 +162,20 @@ struct ltt_session {
         * Keep a state if this session was rotated after the last stop command.
         * We only allow one rotation after a stop. At destroy, we also need to
         * know if a rotation occurred since the last stop to rename the current
-        * chunk.
+        * chunk. After a stop followed by rotate, all subsequent clear
+        * (without prior start) will succeed, but will be effect-less.
         */
        bool rotated_after_last_stop;
+       /*
+        * Track whether the session was cleared after last stop. All subsequent
+        * clear (without prior start) will succeed, but will be effect-less. A
+        * subsequent rotate (without prior start) will return an error.
+        */
+       bool cleared_after_last_stop;
+       /*
+        * True if the session has had an explicit non-quiet rotation.
+        */
+       bool rotated;
        /*
         * Condition and trigger for size-based rotations.
         */
@@ -185,23 +190,37 @@ struct ltt_session {
        char *last_archived_chunk_name;
        LTTNG_OPTIONAL(uint64_t) last_archived_chunk_id;
        struct lttng_dynamic_array destroy_notifiers;
+       struct lttng_dynamic_array clear_notifiers;
        /* Session base path override. Set non-null. */
        char *base_path;
 };
 
-/* Prototypes */
 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
-               const char *base_path, struct ltt_session **out_session);
+               struct ltt_session **out_session);
 void session_lock(struct ltt_session *session);
+void session_unlock(struct ltt_session *session);
+
+/*
+ * The session list lock covers more ground than its name implies. While
+ * it does protect against concurent mutations of the session list, it is
+ * also used as a multi-session lock when synchronizing newly-registered
+ * 'user space tracer' and 'agent' applications.
+ *
+ * In other words, it prevents session configurations from changing while they
+ * are being transmitted to the various applications.
+ */
 void session_lock_list(void);
 int session_trylock_list(void);
-void session_unlock(struct ltt_session *session);
 void session_unlock_list(void);
 
 void session_destroy(struct ltt_session *session);
 int session_add_destroy_notifier(struct ltt_session *session,
                ltt_session_destroy_notifier notifier, void *user_data);
 
+int session_add_clear_notifier(struct ltt_session *session,
+               ltt_session_clear_notifier notifier, void *user_data);
+void session_notify_clear(struct ltt_session *session);
+
 bool session_get(struct ltt_session *session);
 void session_put(struct ltt_session *session);
 
@@ -221,7 +240,7 @@ struct ltt_session *session_find_by_id(uint64_t id);
 struct ltt_session_list *session_get_list(void);
 void session_list_wait_empty(void);
 
-int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid);
+bool session_access_ok(struct ltt_session *session, uid_t uid);
 
 int session_reset_rotation_state(struct ltt_session *session,
                enum lttng_rotation_state result);
@@ -249,9 +268,13 @@ int session_set_trace_chunk(struct ltt_session *session,
  * Close a chunk on the remote peers of a session. Has no effect on the
  * ltt_session itself.
  */
-int session_close_trace_chunk(const struct ltt_session *session,
+int session_close_trace_chunk(struct ltt_session *session,
                struct lttng_trace_chunk *trace_chunk,
-               const enum lttng_trace_chunk_command_type *close_command);
+               enum lttng_trace_chunk_command_type close_command,
+               char *path);
+
+/* Open a packet in all channels of a given session. */
+enum lttng_error_code session_open_packets(struct ltt_session *session);
 
 bool session_output_supports_trace_chunks(const struct ltt_session *session);