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.\" $DragonFly: src/usr.bin/ktrace/ktrace.1,v 1.5 2008/10/16 08:15:18 swildner Exp $ 31.\" 32.Dd June 6, 1993 33.Dt KTRACE 1 34.Os 35.Sh NAME 36.Nm ktrace 37.Nd enable kernel process tracing 38.Sh SYNOPSIS 39.Nm 40.Op Fl aCcdi 41.Op Fl f Ar trfile 42.Op Fl g Ar pgrp | Fl p Ar pid 43.Op Fl t Ar trstr 44.Nm 45.Op Fl adi 46.Op Fl f Ar trfile 47.Op Fl t Ar trstr 48.Ar command 49.Sh DESCRIPTION 50The 51.Nm 52utility enables kernel trace logging for the specified processes. 53Kernel trace data is logged to the file 54.Pa ktrace.out . 55The kernel operations that are traced include system calls, namei 56translations, signal processing, and 57.Tn I/O . 58.Pp 59Once tracing is enabled on a process, trace data will be logged until 60either the process exits or the trace point is cleared. 61A traced process can generate enormous amounts of log data quickly; 62It is strongly suggested that users memorize how to disable tracing before 63attempting to trace a process. 64The following command is sufficient to disable tracing on all user owned 65processes, and, if executed by root, all processes: 66.Pp 67.Dl \&$ ktrace -C 68.Pp 69The trace file is not human readable; use 70.Xr kdump 1 71to decode it. 72.Pp 73The options are as follows: 74.Bl -tag -width indent 75.It Fl a 76Append to the trace file instead of recreating it. 77.It Fl C 78Disable tracing on all user owned processes, and, if executed by root, all 79processes in the system. 80.It Fl c 81Clear the trace points associated with the specified file or processes. 82.It Fl d 83Descendants; perform the operation for all current children of the 84designated processes. 85.It Fl f Ar trfile 86Log trace records to 87.Ar trfile 88instead of 89.Pa ktrace.out . 90.It Fl g Ar pgid 91Enable (disable) tracing on all processes in the process group (only one 92.Fl g 93flag is permitted). 94.It Fl i 95Inherit; pass the trace flags to all future children of the designated 96processes. 97.It Fl p Ar pid 98Enable (disable) tracing on the indicated process id (only one 99.Fl p 100flag is permitted). 101.It Fl t Ar trstr 102The string argument represents the kernel trace points, one per letter. 103The following table equates the letters with the tracepoints: 104.Pp 105.Bl -tag -width flag -compact 106.It Cm c 107trace system calls 108.It Cm n 109trace namei translations 110.It Cm i 111trace 112.Tn 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 EXAMPLES 136# trace all kernel operations of process id 34 137.Dl $ ktrace -p 34 138.Pp 139# trace all kernel operations of processes in process group 15 and 140# pass the trace flags to all current and future children 141.Dl $ ktrace -idg 15 142.Pp 143# disable all tracing of process 65 144.Dl $ ktrace -cp 65 145.Pp 146# disable tracing signals on process 70 and all current children 147.Dl $ ktrace -t s -cdp 70 148.Pp 149# enable tracing of 150.Tn I/O 151on process 67 152.Dl $ ktrace -ti -p 67 153.Pp 154# run the command "w", tracing only system calls 155.Dl $ ktrace -tc w 156.Pp 157# disable all tracing to the file "tracedata" 158.Dl $ ktrace -c -f tracedata 159.Pp 160# disable tracing of all processes owned by the user 161.Dl $ ktrace -C 162.Sh SEE ALSO 163.Xr kdump 1 164.Sh HISTORY 165The 166.Nm 167command appeared in 168.Bx 4.4 . 169.Sh BUGS 170Only works if 171.Ar trfile 172is a regular file. 173