From: Philippe Proulx <eeppeliteloop@gmail.com>
Date: Tue, 23 Apr 2019 23:54:42 +0000 (-0400)
Subject: Fix: bfcr_get_sequence_length_cb(): do not set text array's length
X-Git-Tag: v2.0.0-pre5~76
X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=commitdiff_plain;h=c16748c703b0786c5daf4eda3a8af1da8bdf9cd8

Fix: bfcr_get_sequence_length_cb(): do not set text array's length

Issue
=====
In `msg-iter.c`, bfcr_get_sequence_length_cb() gets called when starting
the decoding of any sequence, including text sequences. However, text
arrays are translated into trace IR string field classes.

bfcr_get_sequence_length_cb() calls bt_field_dynamic_array_set_length()
unconditionally, but its field argument can be a string field at this
point. This is a precondition break.

Solution
========
In bt_field_dynamic_array_set_length(), only call
bt_field_dynamic_array_set_length() if the CTF IR field class is NOT a
text sequence. I'm also adding an assertion to confirm that the trace IR
field is a dynamic array field.

Known drawbacks
===============
None.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
---

diff --git a/plugins/ctf/common/msg-iter/msg-iter.c b/plugins/ctf/common/msg-iter/msg-iter.c
index 0d41638e..9f3dbad9 100644
--- a/plugins/ctf/common/msg-iter/msg-iter.c
+++ b/plugins/ctf/common/msg-iter/msg-iter.c
@@ -2288,11 +2288,23 @@ int64_t bfcr_get_sequence_length_cb(struct ctf_field_class *fc, void *data)
 		seq_fc->stored_length_index);
 	seq_field = stack_top(notit->stack)->base;
 	BT_ASSERT(seq_field);
-	ret = bt_field_dynamic_array_set_length(seq_field, (uint64_t) length);
-	if (ret) {
-		BT_LOGE("Cannot set dynamic array field's length field: "
-			"notit-addr=%p, field-addr=%p, "
-			"length=%" PRIu64, notit, seq_field, length);
+
+	/*
+	 * bfcr_get_sequence_length_cb() also gets called back for a
+	 * text sequence, but the destination field is a string field.
+	 * Only set the field's sequence length if the destination field
+	 * is a sequence field.
+	 */
+	if (!seq_fc->base.is_text) {
+		BT_ASSERT(bt_field_get_class_type(seq_field) ==
+			BT_FIELD_CLASS_TYPE_DYNAMIC_ARRAY);
+		ret = bt_field_dynamic_array_set_length(seq_field,
+			(uint64_t) length);
+		if (ret) {
+			BT_LOGE("Cannot set dynamic array field's length field: "
+				"notit-addr=%p, field-addr=%p, "
+				"length=%" PRIu64, notit, seq_field, length);
+		}
 	}
 
 	return length;