plucky (7) babeltrace2-source.ctf.fs.7.gz
NAME
babeltrace2-source.ctf.fs - Babeltrace 2: File system CTF source component class
DESCRIPTION
A Babeltrace 2 source.ctf.fs message iterator reads one or more CTF 1.8 (see
<https://diamon.org/ctf/v1.8.3/>) or CTF 2 (see <https://diamon.org/ctf/>) data streams on the file
system and emits corresponding messages.
CTF data streams on
the file system
|
| +---------------------+
| | src.ctf.fs |
| | |
'-->| ...5c847 | 0 | 0 @--> Stream 0 messages
| ...5c847 | 0 | 1 @--> Stream 1 messages
| ...5c847 | 0 | 2 @--> Stream 2 messages
+---------------------+
See babeltrace2-intro(7) to learn more about the Babeltrace 2 project and its core concepts.
Input
A source.ctf.fs component opens a single logical CTF trace. A logical CTF trace contains one or more
physical CTF traces. A physical CTF trace on the file system is a directory which contains:
• One metadata stream file named metadata.
• One or more data stream files, that is, any file with a name that does not start with . and which
isn’t metadata.
• Optional: One LTTng (see <https://lttng.org/>) index directory named index.
If the logical CTF trace to handle contains more than one physical CTF trace, then all the physical CTF
traces, depending on the CTF version:
CTF 1.8
Must have a trace UUID and all UUIDs must be the same.
CTF 2
Must have a trace name and a trace unique ID (UID), and all trace namespaces (if any), names, and
UIDs must be the same.
Opening more than one physical CTF trace to constitute a single logical CTF trace is needed to support
LTTng’s tracing session rotation feature, for example (see lttng-rotate(1) starting from LTTng 2.11). In
that case, the component elects the largest metadata stream, considering the total count of data stream
classes and event record classes, as the one to use to decode the data streams of all the physical
traces.
You specify which physical CTF traces to open and read with the inputs array parameter. Each entry in
this array is the path to a physical CTF trace directory, that is, the directory directly containing the
stream files.
A source.ctf.fs component doesn’t recurse into directories to find CTF traces. However, the component
class provides the babeltrace.support-info query object which indicates whether or not a given directory
looks like a CTF trace directory (see “babeltrace.support-info”).
The component creates one output port for each logical CTF data stream. More than one physical CTF data
stream file can support a single logical CTF data stream (LTTng’s trace file rotation and tracing session
rotation can cause this).
If two or more data stream files contain the same packets, then a source.ctf.fs message iterator reads
each of them only once so that it never emits duplicated messages. This feature makes it possible, for
example, to open overlapping LTTng snapshots (see <https://lttng.org/docs/#doc-taking-a-snapshot>) with a
single source.ctf.fs component and silently discard the duplicated packets.
Trace quirks
Many tracers produce CTF traces. A source.ctf.fs component makes some effort to support as many CTF
traces as possible, even those with malformed streams.
In general, for a CTF 1.8 trace:
• If the timestamp_begin or timestamp_end packet context field class exists, but it’s not mapped to a
clock class, and there’s only one clock class at this point in the metadata stream, then the
component maps the field class to this unique clock class.
A source.ctf.fs component has special quirk handling for some LTTng (see <https://lttng.org/>) and
barectf (see <https://lttng.org/>) traces, depending on the tracer version:
All LTTng versions
• For CTF 1.8 traces, the component sets the origin of the monotonic clock class to the Unix epoch
so that different LTTng traces are always correlatable.
This is the equivalent of setting the force-clock-class-origin-unix-epoch parameter to true.
• For a given data stream, for all the contiguous last packets of which the timestamp_end context
field is 0, the message iterator uses the time of the last event record of the packet as the time
of the packet end message.
This is useful for the traces which lttng-crash(1) generates.
LTTng-UST up to, but excluding, 2.11.0, LTTng-modules up to, but excluding, 2.9.13, LTTng-modules from
2.10.0 to 2.10.9
• For a given packet, the message iterator uses the time of the last event record of the packet as
the time of the packet end message, ignoring the timestamp_end packet context field.
barectf up to, but excluding, 2.3.1
• For a given packet, the message iterator uses the time of the first event record of the packet as
the time of the packet beginning message, ignoring the timestamp_begin packet context field.
Message Interchange Protocol (MIP) specifics
A source.ctf.fs component can open and decode, depending on the effective MIP version:
MIP 0
CTF 1.8 traces.
MIP 1
CTF 1.8 and CTF 2 traces.
While the CTF 1.8 metadata stream (TSDL) features naturally map to the MIP 0 API and the CTF 2 ones to
the MIP 1 API, a source.ctf.fs component makes a best effort to represent CTF 1.8 features when working
with MIP 1. In particular, a source.ctf.fs component:
• For an LTTng trace:
• Sets the namespace of any libbabeltrace2 trace to lttng.org,2009.
• Sets the origin of any libbabeltrace2 clock class to the Unix epoch.
• If the UUID of a CTF trace is available, then sets the UID of the corresponding libbabeltrace2 trace
to the textual representation of the trace UUID and its name to an empty string.
• Sets the UID of a libbabeltrace2 clock class to the textual representation of the UUID of its
corresponding CTF clock class, if available.
• Makes the accuracy of any libbabeltrace2 clock class unknown.
When reading a CTF 2 metadata stream (therefore working with MIP 1), a source.ctf.fs component:
• Sets the log level of a libbabeltrace2 event class from the value of the log-level attribute, under
either the lttng.org,2009 or babeltrace.org,2020 namespace, of its corresponding CTF event record
class as such:
"emergency"
BT_EVENT_CLASS_LOG_LEVEL_EMERGENCY
"alert"
BT_EVENT_CLASS_LOG_LEVEL_ALERT
"critical"
BT_EVENT_CLASS_LOG_LEVEL_CRITICAL
"error"
BT_EVENT_CLASS_LOG_LEVEL_ERROR
"warning"
BT_EVENT_CLASS_LOG_LEVEL_WARNING
"notice"
BT_EVENT_CLASS_LOG_LEVEL_NOTICE
"info"
BT_EVENT_CLASS_LOG_LEVEL_INFO
"debug:system"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_SYSTEM
"debug:program"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_PROGRAM
"debug:process"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_PROCESS
"debug:module"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_MODULE
"debug:unit"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_UNIT
"debug:function"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_FUNCTION
"debug:line"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG_LINE
"debug:debug"
BT_EVENT_CLASS_LOG_LEVEL_DEBUG
• Sets the EMF URI of a libbabeltrace2 event class from the value of the emf-uri attribute, under
either the lttng.org,2009 or babeltrace.org,2020 namespace, of its corresponding CTF event record
class.
CTF compliance
A source.ctf.fs component decodes traces as per CTF 1.8 (see <https://diamon.org/ctf/v1.8.3/>) or CTF 2
(see <https://diamon.org/ctf/>), except:
• It only supports fixed-length bit array field classes with sizes from 1 to 64 bits.
This includes fixed-length integers and fixed-length floating point numbers:
CTF 1.8 (TSDL)
integer, enum, and floating_point blocks.
CTF 2
fixed-length-bit-array, fixed-length-bit-map, fixed-length-boolean, fixed-length-unsigned-
integer, fixed-length-signed-integer, and fixed-length-floating-point-number types.
• It only supports the following CTF 2 variable-length integer field values:
variable-length-unsigned-integer
0 to 18,446,744,073,709,551,615 (unsigned 64-bit integer range).
variable-length-signed-integer
-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (signed 64-bit integer range).
• It only supports 32-bit and 64-bit fixed-length floating point number classes:
CTF 1.8 (TSDL)
floating_point block.
CTF 2
fixed-length-floating-point-number type.
• It doesn’t support TSDL § 4.1.6 (“GNU/C bitfields”).
• It doesn’t support TSDL callsite blocks: the CTF 1.8 parser simply ignores them.
• It only supports a single clock class (TSDL clock block or CTF 2 clock-class fragment) reference per
data stream class (TSDL stream block or CTF 2 data-stream-class fragment).
• It doesn’t support the checksum, compression, and encryption features of CTF 1.8 metadata stream
packets.
INITIALIZATION PARAMETERS
clock-class-offset-ns=NS [optional signed integer]
Add NS nanoseconds to the offset of all the clock classes that the component creates.
You can combine this parameter with the clock-class-offset-s parameter.
clock-class-offset-s=SEC [optional signed integer]
Add SEC seconds to the offset of all the clock classes that the component creates.
You can combine this parameter with the clock-class-offset-ns parameter.
force-clock-class-origin-unix-epoch=VAL [optional boolean]
If VAL is true, then force the origin of all clock classes that the component creates to have a Unix
epoch origin, whatever the detected tracer.
Default: false.
inputs=DIRS [array of strings]
Open and read the physical CTF traces located in DIRS.
Each element of DIRS is the path to a physical CTF trace directory containing the trace stream files.
All the specified physical CTF traces must belong to the same logical CTF trace. See “Input” to learn
more about logical and physical CTF traces.
trace-name=NAME [optional string]
Set the name of the trace object that the component creates to NAME.
PORTS
+--------------------+
| src.ctf.fs |
| |
| ...5c847 | 0 | 1 @
| ... @
+--------------------+
Output
A source.ctf.fs component creates one output port for each logical CTF data stream. See “Input” to learn
more about logical and physical CTF data streams.
Each output port name has one of the following forms:
TRACE-ID | STREAM-CLASS-ID | STREAM-ID
TRACE-ID | STREAM-ID
The component uses the second form when the stream class ID isn’t available.
TRACE-ID
If the namespace NS, name NAME, and UID UID of the trace are available, then the exact string:
{namespace: `NS`, name: `NAME`, uid: `UID`}
If the namespace of the trace isn’t available, but the name NAME and UID UID are, then the exact
string:
{name: `NAME`, uid: `UID`}
Otherwise, the absolute directory path of the trace.
Note
The namespace of any LTTng trace is lttng.org,2009. If a CTF 1.8 trace has a UUID, then its
corresponding libbabeltrace2 trace always has a name and a UID (the textual representation of the
UUID).
STREAM-CLASS-ID
Stream class ID.
STREAM-ID
Stream ID if available, otherwise the absolute file path of the stream.
QUERY OBJECTS
babeltrace.support-info
See babeltrace2-query-babeltrace.support-info(7) to learn more about this query object.
For a directory input which is the path to a CTF trace directory, the result object contains:
weight
0.75
group
If the namespace NS, name NAME, and UID UID of the trace are available, then the exact string:
namespace: NS, name: NAME, uid: UID
If the namespace of the trace isn’t available, but the name NAME and UID UID are, then the exact
string:
name: NAME, uid: UID
Otherwise, the entry doesn’t exist.
Note
The namespace of any LTTng trace is lttng.org,2009. If a CTF 1.8 trace has a UUID, then its
corresponding libbabeltrace2 trace always has a name and a UID (the textual representation of the
UUID).
You can leverage the group entry of this query object to assemble many physical CTF traces as a single
logical CTF trace (see “Input” to learn more about logical and physical CTF traces). This is how the
babeltrace2-convert(1) command makes it possible to specify as non-option arguments the paths to multiple
physical CTF traces which belong to the same logical CTF trace and create a single source.ctf.fs
component.
babeltrace.trace-infos
See babeltrace2-query-babeltrace.trace-infos(7) to learn more about this query object.
metadata-info
You can query the metadata-info object for a specific CTF trace to get its plain text metadata stream as
well as whether or not it’s packetized.
Parameters:
path=PATH [string]
Path to the physical CTF trace directory which contains the metadata file.
Result object (map):
is-packetized [boolean]
True if the metadata stream file is packetized.
This is only relevant for a CTF 1.8 metadata stream. Always false with a CTF 2 metadata stream.
text [string]
Plain text metadata stream.
The exact contents of the metadata stream file for a CTF 2 metadata stream.
BUGS
If you encounter any issue or usability problem, please report it on the Babeltrace bug tracker (see
<https://bugs.lttng.org/projects/babeltrace>).
RESOURCES
The Babeltrace project shares some communication channels with the LTTng project (see
<https://lttng.org/>).
• Babeltrace website (see <https://babeltrace.org/>)
• Mailing list (see <https://lists.lttng.org>) for support and development: lttng-dev@lists.lttng.org
• IRC channel (see <irc://irc.oftc.net/lttng>): #lttng on irc.oftc.net
• Bug tracker (see <https://bugs.lttng.org/projects/babeltrace>)
• Git repository (see <https://git.efficios.com/?p=babeltrace.git>)
• GitHub project (see <https://github.com/efficios/babeltrace>)
• Continuous integration (see <https://ci.lttng.org/view/Babeltrace/>)
• Code review (see <https://review.lttng.org/q/project:babeltrace>)
AUTHORS
The Babeltrace 2 project is the result of hard work by many regular developers and occasional
contributors.
The current project maintainer is Jérémie Galarneau <mailto:jeremie.galarneau@efficios.com>.
COPYRIGHT
This component class is part of the Babeltrace 2 project.
Babeltrace is distributed under the MIT license (see <https://opensource.org/licenses/MIT>).
SEE ALSO
babeltrace2-intro(7), babeltrace2-plugin-ctf(7), lttng-crash(1) BABELTRACE2-SOURCE()