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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: jgalar@efficios.com
Cc: lttng-dev@lists.lttng.org
Subject: [PATCH babeltrace-1.5 6/6] Fix: lttng-live format: do not error out on empty streams hang up
Date: Thu,  5 Dec 2019 01:58:09 -0500	[thread overview]
Message-ID: <20191205065809.16728-7-mathieu.desnoyers__23563.4265862004$1575529305$gmane$org@efficios.com> (raw)
In-Reply-To: <20191205065809.16728-1-mathieu.desnoyers@efficios.com>

Attaching to a stream hung up before providing any trace packet
causes ctf_open_mmap_stream_read() to return an error.

This kind of scenario can happen with the upcoming "lttng clear"
feature.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 formats/ctf/ctf.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index 980ebc9a..1ba9017f 100644
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -2571,8 +2571,13 @@ int ctf_open_mmap_stream_read(struct ctf_trace *td,
 	}
 
 	ret = prepare_mmap_stream_definition(td, file_stream, packet_seek);
-	if (ret)
+	if (ret) {
+		/* We need to check for EOF here for empty files. */
+		if (unlikely(file_stream->pos.offset == EOF)) {
+			ret = 0;
+		}
 		goto error_index;
+	}
 
 	/*
 	 * For now, only a single clock per trace is supported.
-- 
2.17.1

  parent reply	other threads:[~2019-12-05  6:58 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191205065809.16728-1-mathieu.desnoyers@efficios.com>
2019-12-05  6:58 ` [PATCH babeltrace-1.5 1/6] Fix: lttng-live: use-after-free in get_next_index() Mathieu Desnoyers
2019-12-05  6:58 ` [PATCH babeltrace-1.5 2/6] Fix: trace-collection: trace clock use after free Mathieu Desnoyers
2019-12-05  6:58 ` [PATCH babeltrace-1.5 3/6] Fix: lttng-live: lttng_live_open_trace_read memory leak Mathieu Desnoyers
2019-12-05  6:58 ` [PATCH babeltrace-1.5 4/6] Fix: lib/iterator.c: unbalanced ctx put (leak) Mathieu Desnoyers
2019-12-05  6:58 ` [PATCH babeltrace-1.5 5/6] Fix: lttng-live: ctf_live_packet_seek stream hang up handling Mathieu Desnoyers
2019-12-05  6:58 ` Mathieu Desnoyers [this message]
     [not found] ` <20191205065809.16728-7-mathieu.desnoyers@efficios.com>
2019-12-13  1:03   ` [PATCH babeltrace-1.5 6/6] Fix: lttng-live format: do not error out on empty streams hang up Jérémie Galarneau

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