1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)ktrace.1 8.1 (Berkeley) 6/6/93 29.\" $FreeBSD: src/usr.bin/ktrace/ktrace.1,v 1.8.2.8 2002/06/21 15:27:30 charnier Exp $ 30.\" 31.Dd October 5, 2017 32.Dt KTRACE 1 33.Os 34.Sh NAME 35.Nm ktrace 36.Nd enable kernel process tracing 37.Sh SYNOPSIS 38.Nm 39.Op Fl aCcdi 40.Op Fl f Ar trfile 41.Op Fl g Ar pgrp | Fl p Ar pid 42.Op Fl t Ar trstr 43.Nm 44.Op Fl adi 45.Op Fl f Ar trfile 46.Op Fl t Ar trstr 47.Ar command 48.Sh DESCRIPTION 49The 50.Nm 51utility enables kernel trace logging for the specified processes. 52By default, kernel trace data is logged to the file 53.Pa ktrace.out , 54this may be overridden by the 55.Fl f 56option. 57The kernel operations that are traced include system calls, namei 58translations, signal processing, and I/O. 59.Pp 60Once tracing is enabled on a process, trace data will be logged until 61either the process exits or the trace point is cleared. 62A traced process can generate enormous amounts of log data quickly; 63It is strongly suggested that users memorize how to disable tracing before 64attempting to trace a process. 65The following command is sufficient to disable tracing on all user owned 66processes, and, if executed by root, all processes: 67.Pp 68.Dl \&$ ktrace -C 69.Pp 70The trace file is not human readable; use 71.Xr kdump 1 72to decode it. 73.Pp 74The options are as follows: 75.Bl -tag -width indent 76.It Fl a 77Append to the trace file instead of recreating it. 78.It Fl C 79Disable tracing on all user owned processes, and, if executed by root, all 80processes in the system. 81.It Fl c 82Clear the trace points associated with the specified file or processes. 83.It Fl d 84Descendants; perform the operation for all current children of the 85designated processes. 86.It Fl f Ar trfile 87Log trace records to 88.Ar trfile 89instead of 90.Pa ktrace.out . 91.It Fl g Ar pgid 92Enable (disable) tracing on all processes in the process group (only one 93.Fl g 94flag is permitted). 95.It Fl i 96Inherit; pass the trace flags to all future children of the designated 97processes. 98.It Fl p Ar pid 99Enable (disable) tracing on the indicated process id (only one 100.Fl p 101flag is permitted). 102.It Fl t Ar trstr 103The string argument represents the kernel trace points, one per letter. 104The following table equates the letters with the tracepoints: 105.Pp 106.Bl -tag -width flag -compact 107.It Cm c 108trace system calls 109.It Cm n 110trace namei translations 111.It Cm i 112trace I/O 113.It Cm s 114trace signal processing 115.It Cm u 116userland traces 117.It Cm w 118context switches 119.It Cm + 120trace the default set of trace points - 121.Cm c , n , i , s , u 122.El 123.It Ar command 124Execute 125.Ar command 126with the specified trace flags. 127.El 128.Pp 129The 130.Fl p , 131.Fl g , 132and 133.Ar command 134options are mutually exclusive. 135.Sh FILES 136.Bl -tag -width ktrace.out -compact 137.It Pa ktrace.out 138default ktrace dump file 139.El 140.Sh EXAMPLES 141# trace all kernel operations of process id 34 142.Dl $ ktrace -p 34 143.Pp 144# trace all kernel operations of processes in process group 15 and 145# pass the trace flags to all current and future children 146.Dl $ ktrace -idg 15 147.Pp 148# disable all tracing of process 65 149.Dl $ ktrace -cp 65 150.Pp 151# disable tracing signals on process 70 and all current children 152.Dl $ ktrace -t s -cdp 70 153.Pp 154# enable tracing of I/O 155on process 67 156.Dl $ ktrace -ti -p 67 157.Pp 158# run the command "w", tracing only system calls 159.Dl $ ktrace -tc w 160.Pp 161# disable all tracing to the file "tracedata" 162.Dl $ ktrace -c -f tracedata 163.Pp 164# disable tracing of all processes owned by the user 165.Dl $ ktrace -C 166.Sh SEE ALSO 167.Xr kdump 1 , 168.Xr ktrace 2 , 169.Xr utrace 2 170.Sh HISTORY 171The 172.Nm 173command appeared in 174.Bx 4.4 . 175.Sh BUGS 176Only works if 177.Ar trfile 178is a regular file. 179