'\" t
.\"     Title: lttng-track
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 14 June 2021
.\"    Manual: LTTng Manual
.\"    Source: LTTng 2.13.15
.\"  Language: English
.\"
.TH "LTTNG\-TRACK" "1" "14 June 2021" "LTTng 2\&.13\&.15" "LTTng Manual"
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.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.nh
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.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
lttng-track \- Allow specific processes to record LTTng events
.SH "SYNOPSIS"
.sp
Allow specific processes to record Linux kernel events:
.sp
.nf
\fBlttng\fR [\fIGENERAL OPTIONS\fR] \fBtrack\fR \fB--kernel\fR [\fB--session\fR=\fISESSION\fR]
      (\fB--pid\fR=PID[,PID]\&... | \fB--vpid\fR=VPID[,VPID]\&... |
       \fB--uid\fR=UID[,UID]\&... | \fB--vuid\fR=VUSER[,VUSER]\&... |
       \fB--gid\fR=GID[,GID]\&... | \fB--vgid\fR=VGROUP[,VGROUP]\&...)\&...
.fi
.sp
.nf
\fBlttng\fR [\fIGENERAL OPTIONS\fR] \fBtrack\fR \fB--kernel\fR [\fB--session\fR=\fISESSION\fR]
      \fB--all\fR (\fB--pid\fR | \fB--vpid\fR | \fB--uid\fR | \fB--vuid\fR | \fB--gid\fR | \fB--vgid\fR)\&...
.fi
.sp
Allow specific processes to record user space events:
.sp
.nf
\fBlttng\fR [\fIGENERAL OPTIONS\fR] \fBtrack\fR \fB--userspace\fR [\fB--session\fR=\fISESSION\fR]
      (\fB--vpid\fR=VPID[,VPID]\&... | \fB--vuid\fR=VUSER[,VUSER]\&... |
       \fB--vgid\fR=VGROUP[,VGROUP]\&...)\&...
.fi
.sp
.nf
\fBlttng\fR [\fIGENERAL OPTIONS\fR] \fBtrack\fR \fB--userspace\fR [\fB--session\fR=\fISESSION\fR]
      \fB--all\fR (\fB--vpid\fR | \fB--vgid\fR | \fB--vuid\fR)\&...
.fi
.SH "DESCRIPTION"
.sp
The \fBlttng track\fR command allows one or more processes to record LTTng events based on their attributes within:
.PP
With the \fB--session\fR=\fISESSION\fR option
.RS 4
The recording session named
\fISESSION\fR\&.
.RE
.PP
Without the \fB--session\fR option
.RS 4
The current recording session (see
\fBlttng-concepts\fR(7)
to learn more about the current recording session)\&.
.RE
.sp
See \fBlttng-concepts\fR(7) to learn more about recording sessions and recording event rules\&.
.sp
The \fBtrack\fR command adds values to \fIinclusion sets\fR of process attributes\&. The available inclusion sets are, for a given recording session:
.PP
With the \fB--kernel\fR option
.RS 4
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Process ID (PID)\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Virtual process ID (VPID)\&.
.sp
This is the PID as seen by the application\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Unix user ID (UID)\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Virtual Unix user ID (VUID)\&.
.sp
This is the UID as seen by the application\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Unix group ID (GID)\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Virtual Unix group ID (VGID)\&.
.sp
This is the GID as seen by the application\&.
.RE
.RE
.PP
With the \fB--userspace\fR option
.RS 4
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
VPID
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
VUID
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
VGID
.RE
.RE
.sp
When an event\ \&\fIE\fR satisfies all the other explicit and implicit conditions of an event rule\ \&\fIER\fR, \fIER\fR matches\ \&\fIE\fR if the attributes of the process for which LTTng creates\ \&\fIE\fR are \fBall\fR part of the inclusion sets of the recording session and domain of\ \&\fIER\fR\&.
.sp
By default, on recording session creation (see \fBlttng-create\fR(1)), all processes are allowed to record events\&. In other words, all the inclusion sets of the recording session contain all the possible process attribute values\&.
.sp
If a given inclusion set\ \&\fIIS\fR contains all the possible values (\fB--all\fR option), then using the \fBtrack\fR command to add one or more values\ \&\fIV\fR to\ \&\fIIS\fR:
.sp
.RS 4
.ie n \{\
\h'-04' 1.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  1." 4.2
.\}
Removes all the values from\ \&\fIIS\fR\&.
.sp
This effectively makes\ \&\fIIS\fR
empty\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 2.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  2." 4.2
.\}
Adds\ \&\fIV\fR
to\ \&\fIIS\fR\&.
.RE
.sp
Example: with the PID inclusion set, you can record all the system calls of a given process:
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng enable\-event \-\-kernel \-\-all \-\-syscall
$ lttng track \-\-kernel \-\-pid=2345
$ lttng start
.fi
.if n \{\
.RE
.\}
.sp
See the \(lqEXAMPLES\(rq section below for usage examples\&.
.sp
Remove values from an inclusion set with the \fBlttng-untrack\fR(1) command\&.
.SS "Inclusion set example"
.sp
This example operates on the Linux kernel process ID (PID) inclusion set of the current recording session to show how an inclusion set works\&.
.sp
Assume the maximum system PID is 7 for this example\&.
.sp
.RS 4
.ie n \{\
\h'-04' 1.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  1." 4.2
.\}
Initial inclusion set:
.sp
.if n \{\
.RS 4
.\}
.nf
[0] [1] [2] [3] [4] [5] [6] [7]
.fi
.if n \{\
.RE
.\}
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 2.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  2." 4.2
.\}
Command:
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng track \-\-kernel \-\-pid=3,6,7
.fi
.if n \{\
.RE
.\}
.sp
Inclusion set is now:
.sp
.if n \{\
.RS 4
.\}
.nf
[ ] [ ] [ ] [3] [ ] [ ] [6] [7]
.fi
.if n \{\
.RE
.\}
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 3.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  3." 4.2
.\}
Command:
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng untrack \-\-kernel \-\-pid=7
.fi
.if n \{\
.RE
.\}
.sp
Inclusion set is now:
.sp
.if n \{\
.RS 4
.\}
.nf
[ ] [ ] [ ] [3] [ ] [ ] [6] [ ]
.fi
.if n \{\
.RE
.\}
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 4.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  4." 4.2
.\}
Command:
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng track \-\-kernel \-\-pid=1,5
.fi
.if n \{\
.RE
.\}
.sp
Inclusion set is now:
.sp
.if n \{\
.RS 4
.\}
.nf
[ ] [1] [ ] [3] [ ] [5] [6] [ ]
.fi
.if n \{\
.RE
.\}
.RE
.sp
Remove values from an inclusion set with the \fBlttng-untrack\fR(1) command\&.
.SH "OPTIONS"
.sp
See \fBlttng\fR(1) for \fIGENERAL OPTIONS\fR\&.
.SS "Tracing domain"
.sp
One of:
.PP
\fB-k\fR, \fB--kernel\fR
.RS 4
Add values to one or more Linux kernel inclusion sets\&.
.RE
.PP
\fB-u\fR, \fB--userspace\fR
.RS 4
Add values to one or more user space inclusion sets\&.
.RE
.SS "Recording target"
.PP
\fB-s\fR \fISESSION\fR, \fB--session\fR=\fISESSION\fR
.RS 4
Add values to one or more inclusion sets of the recording session named
\fISESSION\fR
instead of the current recording session\&.
.RE
.SS "Inclusion set selection"
.PP
\fB-p\fR [\fIPID\fR[,\fIPID\fR]\&...], \fB--pid\fR[=\fIPID\fR[,\fIPID\fR]\&...]
.RS 4
For each
\fIPID\fR
argument, add
\fIPID\fR
to the process ID inclusion set of the selected recording session and domain\&.
.sp
\fIPID\fR
is the process ID attribute of a process as seen from the root PID namespace (see
\fBpid_namespaces\fR(7))\&.
.sp
Only available with
\fB--kernel\fR
option\&.
.RE
.PP
\fB--vpid\fR[=\fIVPID\fR[,\fIVPID\fR]\&...]
.RS 4
For each
\fIVPID\fR
argument, add
\fIVPID\fR
to the virtual process ID inclusion set of the selected recording session and domain\&.
.sp
\fIVPID\fR
is the virtual process ID attribute of a process as seen from the PID namespace of the process (see
\fBpid_namespaces\fR(7))\&.
.RE
.PP
\fB--uid\fR[=\fIUSER\fR[,\fIUSER\fR]\&...]
.RS 4
For each
\fIUSER\fR
argument, add
\fIUSER\fR
to the user ID inclusion set of the selected recording session and domain\&.
.sp
\fIUSER\fR
is either:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The real user ID (see
\fBgetuid\fR(3)) of a process as seen from the root user namespace (see
\fBuser_namespaces\fR(7))\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
A user name\&.
.sp
The connected LTTng session daemon (see
\fBlttng-sessiond\fR(8)) performs the user name resolution on addition to the user ID inclusion set\&.
.RE
.sp
Only available with
\fB--kernel\fR
option\&.
.RE
.PP
\fB--vuid\fR[=\fIVUSER\fR[,\fIVUSER\fR]\&...]
.RS 4
For each
\fIVUSER\fR
argument, add
\fIVUSER\fR
to the virtual user ID inclusion set of the selected recording session and domain\&.
.sp
\fIVUSER\fR
is either:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The real user ID (see
\fBgetuid\fR(3)) of a process as seen from the user namespace (see
\fBuser_namespaces\fR(7))\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
A user name\&.
.sp
The connected LTTng session daemon (see
\fBlttng-sessiond\fR(8)) performs the user name resolution on addition to the virtual user ID inclusion set\&.
.RE
.RE
.PP
\fB--gid\fR[=\fIGROUP\fR[,\fIGROUP\fR]\&...]
.RS 4
For each
\fIGROUP\fR
argument, add
\fIGROUP\fR
to the group ID inclusion set of the selected recording session and domain\&.
.sp
\fIGROUP\fR
is either:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The real group ID (see
\fBgetgid\fR(3)) of a process as seen from the root user namespace (see
\fBuser_namespaces\fR(7))\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
A group name\&.
.sp
The connected LTTng session daemon (see
\fBlttng-sessiond\fR(8)) performs the group name resolution on addition to the group ID inclusion set\&.
.RE
.sp
Only available with
\fB--kernel\fR
option\&.
.RE
.PP
\fB--vgid\fR[=\fIVGROUP\fR[,\fIVGROUP\fR]\&...]
.RS 4
For each
\fIVGROUP\fR
argument, add
\fIVGROUP\fR
to the virtual group ID inclusion set of the selected recording session and domain\&.
.sp
\fIVGROUP\fR
is either:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The real group ID (see
\fBgetgid\fR(3)) of a process as seen from the user namespace (see
\fBuser_namespaces\fR(7))\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
A group name\&.
.sp
The connected LTTng session daemon (see
\fBlttng-sessiond\fR(8)) performs the group name resolution on addition to the virtual group ID inclusion set\&.
.RE
.RE
.SS "Inclusion set operation"
.PP
\fB-a\fR, \fB--all\fR
.RS 4
With one or more empty
\fB--pid\fR,
\fB--vpid\fR,
\fB--uid\fR,
\fB--vuid\fR,
\fB--gid\fR, and
\fB--vgid\fR
options: add
\fBall\fR
the possible values to the selected inclusion sets\&.
.RE
.SS "Program information"
.PP
\fB-h\fR, \fB--help\fR
.RS 4
Show help\&.
.sp
This option attempts to launch
\fB/usr/bin/man\fR
to view this manual page\&. Override the manual pager path with the
\fBLTTNG_MAN_BIN_PATH\fR
environment variable\&.
.RE
.PP
\fB--list-options\fR
.RS 4
List available command options and quit\&.
.RE
.SH "EXIT STATUS"
.PP
\fB0\fR
.RS 4
Success
.RE
.PP
\fB1\fR
.RS 4
Command error
.RE
.PP
\fB2\fR
.RS 4
Undefined command
.RE
.PP
\fB3\fR
.RS 4
Fatal error
.RE
.PP
\fB4\fR
.RS 4
Command warning (something went wrong during the command)
.RE
.SH "ENVIRONMENT"
.PP
\fBLTTNG_ABORT_ON_ERROR\fR
.RS 4
Set to
\fB1\fR
to abort the process after the first error is encountered\&.
.RE
.PP
\fBLTTNG_HOME\fR
.RS 4
Path to the LTTng home directory\&.
.sp
Defaults to
\fB$HOME\fR\&.
.sp
Useful when the Unix user running the commands has a non\-writable home directory\&.
.RE
.PP
\fBLTTNG_MAN_BIN_PATH\fR
.RS 4
Absolute path to the manual pager to use to read the LTTng command\-line help (with
\fBlttng-help\fR(1)
or with the
\fB--help\fR
option) instead of
\fB/usr/bin/man\fR\&.
.RE
.PP
\fBLTTNG_SESSION_CONFIG_XSD_PATH\fR
.RS 4
Path to the directory containing the
\fBsession.xsd\fR
recording session configuration XML schema\&.
.RE
.PP
\fBLTTNG_SESSIOND_PATH\fR
.RS 4
Absolute path to the LTTng session daemon binary (see
\fBlttng-sessiond\fR(8)) to spawn from the
\fBlttng-create\fR(1)
command\&.
.sp
The
\fB--sessiond-path\fR
general option overrides this environment variable\&.
.RE
.SH "FILES"
.PP
\fB$LTTNG_HOME/.lttngrc\fR
.RS 4
Unix user\(cqs LTTng runtime configuration\&.
.sp
This is where LTTng stores the name of the Unix user\(cqs current recording session between executions of
\fBlttng\fR(1)\&.
\fBlttng-create\fR(1)
and
\fBlttng-set-session\fR(1)
set the current recording session\&.
.RE
.PP
\fB$LTTNG_HOME/lttng-traces\fR
.RS 4
Default output directory of LTTng traces in local and snapshot modes\&.
.sp
Override this path with the
\fB--output\fR
option of the
\fBlttng-create\fR(1)
command\&.
.RE
.PP
\fB$LTTNG_HOME/.lttng\fR
.RS 4
Unix user\(cqs LTTng runtime and configuration directory\&.
.RE
.PP
\fB$LTTNG_HOME/.lttng/sessions\fR
.RS 4
Default directory containing the Unix user\(cqs saved recording session configurations (see
\fBlttng-save\fR(1)
and
\fBlttng-load\fR(1))\&.
.RE
.PP
\fB/usr/local/etc/lttng/sessions\fR
.RS 4
Directory containing the system\-wide saved recording session configurations (see
\fBlttng-save\fR(1)
and
\fBlttng-load\fR(1))\&.
.RE
.if n \{\
.sp
.\}
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
.ps +1
\fBNote\fR
.ps -1
.br
.RS 4
.sp
\fB$LTTNG_HOME\fR defaults to the value of the \fBHOME\fR environment variable\&.
.sp .5v
.RE
.SH "EXAMPLES"
.PP
\fBExample\ \&1.\ \&Add the PIDs 1728 and 3775 to the Linux kernel process ID inclusion set of the current recording session\&.\fR
.RS 4
.sp
See the \fB--pid\fR option\&.
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng track \-\-kernel \-\-pid=1728,3775
.fi
.if n \{\
.RE
.\}
.RE
.PP
\fBExample\ \&2.\ \&Add the ID of a specific user to the user space virtual user ID inclusion set of a specific recording session\&.\fR
.RS 4
.sp
See the \fB--vuid\fR and \fB--session\fR options\&.
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng track \-\-userspace \-\-session=my\-session \-\-vuid=http
.fi
.if n \{\
.RE
.\}
.RE
.PP
\fBExample\ \&3.\ \&Add all the possible group IDs to the Linux kernel group ID inclusion set of the current recording session\&.\fR
.RS 4
.sp
See the \fB--all\fR and \fB--gid\fR options\&.
.sp
.if n \{\
.RS 4
.\}
.nf
$ lttng track \-\-kernel \-\-all \-\-gid
.fi
.if n \{\
.RE
.\}
.RE
.SH "RESOURCES"
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng project website <https://lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng documentation <https://lttng.org/docs>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
LTTng bug tracker <https://bugs.lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Git repositories <https://git.lttng.org>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
GitHub organization <https://github.com/lttng>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Continuous integration <https://ci.lttng.org/>
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Mailing list <https://lists.lttng.org/>
for support and development:
\fBlttng-dev@lists.lttng.org\fR
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
IRC channel <irc://irc.oftc.net/lttng>:
\fB#lttng\fR
on
\fBirc.oftc.net\fR
.RE
.SH "COPYRIGHT"
.sp
This program is part of the LTTng\-tools project\&.
.sp
LTTng\-tools is distributed under the GNU General Public License version\ \&2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>\&. See the \fBLICENSE\fR <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file for details\&.
.SH "THANKS"
.sp
Special thanks to Michel Dagenais and the DORSAL laboratory <http://www.dorsal.polymtl.ca/> at \('Ecole Polytechnique de Montr\('eal for the LTTng journey\&.
.sp
Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases\&.
.SH "SEE ALSO"
.sp
\fBlttng\fR(1), \fBlttng-untrack\fR(1), \fBlttng-concepts\fR(7)