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