Fix: bt_stream_class_map_clock_class(): copy field type when mapping

Issue
=====
When a CTF writer stream class's packet context type contains the
special field types `timestamp_begin`, `timestamp_end`, and `timestamp`,
they are automatically mapped to the stream class's clock's class when
the stream class is about to be frozen in bt_trace_add_stream_class().
However, because the field type is mapped as is without a prior copy, it
is possible that this field type is shared with other locations in the
metadata tree which should not be mapped to a clock class.

Solution
========
Before automatically mapping any field type to a clock class, or more
generally, before modifying any field type, make a copy and replace the
original within its parent.

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

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

diff --git a/lib/ctf-ir/stream-class.c b/lib/ctf-ir/stream-class.c
index d1dc9bda029563f56274c81c656082ddb3253b16..fe33b61d59af38f7335e14d737dfea851a8c05cd 100644 (file)
--- a/lib/ctf-ir/stream-class.c
+++ b/lib/ctf-ir/stream-class.c
@@ -1280,10 +1280,15 @@ end:
 
 static
 int try_map_clock_class(struct bt_stream_class *stream_class,
-               struct bt_field_type *ft)
+               struct bt_field_type *parent_ft, const char *field_name)
 {
        struct bt_clock_class *mapped_clock_class = NULL;
        int ret = 0;
+       struct bt_field_type *ft =
+               bt_field_type_structure_get_field_type_by_name(parent_ft,
+                       field_name);
+
+       assert(stream_class->clock);
 
        if (!ft) {
                /* Field does not exist: not an error */
@@ -1294,6 +1299,8 @@ int try_map_clock_class(struct bt_stream_class *stream_class,
        mapped_clock_class =
                bt_field_type_integer_get_mapped_clock_class(ft);
        if (!mapped_clock_class) {
+               struct bt_field_type *ft_copy;
+
                if (!stream_class->clock) {
                        BT_LOGW("Cannot automatically set field's type mapped clock class: stream class's clock is not set: "
                                "stream-class-addr=%p, stream-class-name=\"%s\", "
@@ -1304,25 +1311,28 @@ int try_map_clock_class(struct bt_stream_class *stream_class,
                        goto end;
                }
 
-               ret = bt_field_type_integer_set_mapped_clock_class_no_check(
-                       ft, stream_class->clock->clock_class);
-               if (ret) {
-                       BT_LOGW("Cannot set field type's mapped clock class: "
-                               "stream-class-addr=%p, stream-class-name=\"%s\", "
-                               "stream-class-id=%" PRId64 ", ft-addr=%p",
-                               stream_class, bt_stream_class_get_name(stream_class),
-                               bt_stream_class_get_id(stream_class), ft);
-                       goto end;
+               ft_copy = bt_field_type_copy(ft);
+               if (!ft_copy) {
+                       BT_LOGE("Failed to copy integer field type: ft-addr=%p",
+                               ft);
                }
 
+               ret = bt_field_type_integer_set_mapped_clock_class_no_check(
+                       ft_copy, stream_class->clock->clock_class);
+               assert(ret == 0);
+               ret = bt_field_type_structure_replace_field(parent_ft,
+                       field_name, ft_copy);
+               bt_put(ft_copy);
                BT_LOGV("Automatically mapped field type to stream class's clock class: "
                        "stream-class-addr=%p, stream-class-name=\"%s\", "
-                       "stream-class-id=%" PRId64 ", ft-addr=%p",
+                       "stream-class-id=%" PRId64 ", ft-addr=%p, "
+                       "ft-copy-addr=%p",
                        stream_class, bt_stream_class_get_name(stream_class),
-                       bt_stream_class_get_id(stream_class), ft);
+                       bt_stream_class_get_id(stream_class), ft, ft_copy);
        }
 
 end:
+       bt_put(ft);
        bt_put(mapped_clock_class);
        return ret;
 }
@@ -1333,42 +1343,38 @@ int bt_stream_class_map_clock_class(
                struct bt_field_type *packet_context_type,
                struct bt_field_type *event_header_type)
 {
-       struct bt_field_type *ft = NULL;
        int ret = 0;
 
        assert(stream_class);
 
+       if (!stream_class->clock) {
+               /* No clock class to map to */
+               goto end;
+       }
+
        if (packet_context_type) {
-               ft = bt_field_type_structure_get_field_type_by_name(
-                       packet_context_type, "timestamp_begin");
-               if (try_map_clock_class(stream_class, ft)) {
+               if (try_map_clock_class(stream_class, packet_context_type,
+                               "timestamp_begin")) {
                        BT_LOGE_STR("Cannot automatically set stream class's packet context field type's `timestamp_begin` field's mapped clock class.");
                        ret = -1;
                        goto end;
                }
 
-               bt_put(ft);
-               ft = bt_field_type_structure_get_field_type_by_name(
-                       packet_context_type, "timestamp_end");
-               if (try_map_clock_class(stream_class, ft)) {
+               if (try_map_clock_class(stream_class, packet_context_type,
+                               "timestamp_end")) {
                        BT_LOGE_STR("Cannot automatically set stream class's packet context field type's `timestamp_end` field's mapped clock class.");
                        ret = -1;
                        goto end;
                }
-
-               BT_PUT(ft);
        }
 
        if (event_header_type) {
-               ft = bt_field_type_structure_get_field_type_by_name(
-                       event_header_type, "timestamp");
-               if (try_map_clock_class(stream_class, ft)) {
+               if (try_map_clock_class(stream_class, event_header_type,
+                               "timestamp")) {
                        BT_LOGE_STR("Cannot automatically set stream class's event header field type's `timestamp` field's mapped clock class.");
                        ret = -1;
                        goto end;
                }
-
-               BT_PUT(ft);
        }
 
 end:

diff --git a/lib/ctf-ir/trace.c b/lib/ctf-ir/trace.c
index d1efd9f9468c07c18c35d840804dbd3efee622a0..284427ee8e260bcc33f006b765e37060d1bc9688 100644 (file)
--- a/lib/ctf-ir/trace.c
+++ b/lib/ctf-ir/trace.c
@@ -1516,8 +1516,6 @@ int bt_trace_add_stream_class(struct bt_trace *trace,
                }
        }
 
-
-
        bt_object_set_parent(stream_class, trace);
        g_ptr_array_add(trace->stream_classes, stream_class);