X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Fsessiond-comm%2Frelayd.h;h=36a91070cbfd0cf6a587d238f6712912b9b78de0;hb=4878de5c7deb512bbdac4fdfc498907efa06fb7c;hp=492f3efae5ee722cc17bb3fb649028c1af06e136;hpb=8614e600d7a8dc653c473254fc302870d73f32ae;p=lttng-tools.git

diff --git a/src/common/sessiond-comm/relayd.h b/src/common/sessiond-comm/relayd.h
index 492f3efae..36a91070c 100644
--- a/src/common/sessiond-comm/relayd.h
+++ b/src/common/sessiond-comm/relayd.h
@@ -1,19 +1,9 @@
 /*
- * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
- *                      Julien Desfossez <julien.desfossez@efficios.com>
+ * Copyright (C) 2012 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2012 Julien Desfossez <julien.desfossez@efficios.com>
  *
- * 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 _RELAYD_COMM
@@ -214,7 +204,7 @@ struct lttcomm_relayd_create_session_2_11 {
 	/* Sessiond instance UUID */
 	lttng_uuid sessiond_uuid;
 	/* Sessiond session id */
-        uint64_t session_id;
+	uint64_t session_id;
 	/* Session creation time, in seconds since UNIX Epoch. */
 	uint64_t creation_time;
 	LTTNG_OPTIONAL_COMM(uint64_t) LTTNG_PACKED current_chunk_id;
@@ -249,17 +239,70 @@ struct lttcomm_relayd_stream_rotation_position {
 	uint64_t rotate_at_seq_num;
 } LTTNG_PACKED;
 
+/*
+ * For certain releases, the LTTNG_PACKED annotation was missing on the
+ * `new_chunk_id` field which causes padding to be added between the
+ * "optional" structure's `is_set` and `value` fields.
+ *
+ * Three alignment cases are handled:
+ *   - `value` is aligned to the next byte boundary after `is_set`
+ *     no padding is produced, see
+ *     `struct lttcomm_relayd_rotate_streams_packed`,
+ *   - `value` is aligned to the next 4-byte boundary after `is_set`
+ *     (e.g. x86), 3 bytes of padding are produced, see
+ *     `struct lttcomm_relayd_rotate_streams_3_bytes_padding`,
+ *   - `value` is aligned to the next 8-byte boundary after `is_set`
+ *     (e.g. x86-64), 7 bytes of padding are produced, see
+ *     `struct lttcomm_relayd_rotate_streams_7_bytes_padding`.
+ *
+ * Note that since this structure's advertised size is used to determine
+ * the size of the padding it includes, it can't be extended with new
+ * optional fields. A new command would be needed.
+ */
 struct lttcomm_relayd_rotate_streams {
 	uint32_t stream_count;
 	/*
 	 * Streams can be rotated outside of a chunk but not be parented to
 	 * a new chunk.
+	 *
+	 * Improperly packed, but left as-is for backwards compatibility
+	 * with unpatched relay daemons.
 	 */
 	LTTNG_OPTIONAL_COMM(uint64_t) new_chunk_id;
 	/* `stream_count` positions follow. */
 	struct lttcomm_relayd_stream_rotation_position rotation_positions[];
 } LTTNG_PACKED;
 
+struct lttcomm_relayd_rotate_streams_packed {
+	uint32_t stream_count;
+	LTTNG_OPTIONAL_COMM(uint64_t) LTTNG_PACKED new_chunk_id;
+	struct lttcomm_relayd_stream_rotation_position rotation_positions[];
+} LTTNG_PACKED;
+
+struct lttcomm_relayd_rotate_streams_3_bytes_padding {
+	uint32_t stream_count;
+	struct {
+		union {
+			uint8_t is_set;
+			uint32_t padding;
+		};
+		uint64_t value;
+	} LTTNG_PACKED new_chunk_id;
+	struct lttcomm_relayd_stream_rotation_position rotation_positions[];
+} LTTNG_PACKED;
+
+struct lttcomm_relayd_rotate_streams_7_bytes_padding {
+	uint32_t stream_count;
+	struct {
+		union {
+			uint8_t is_set;
+			uint64_t padding;
+		};
+		uint64_t value;
+	} LTTNG_PACKED new_chunk_id;
+	struct lttcomm_relayd_stream_rotation_position rotation_positions[];
+} LTTNG_PACKED;
+
 struct lttcomm_relayd_create_trace_chunk {
 	uint64_t chunk_id;
 	/* Seconds since EPOCH. */