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.\" 30.Dd August 26, 2019 31.Dt KTRACE 1 32.Os 33.Sh NAME 34.Nm ktrace 35.Nd enable kernel process tracing 36.Sh SYNOPSIS 37.Nm 38.Op Fl aCcdi 39.Op Fl f Ar trfile 40.Op Fl g Ar pgrp | Fl p Ar pid 41.Op Fl t Ar trstr 42.Nm 43.Op Fl adi 44.Op Fl f Ar trfile 45.Op Fl t Ar trstr 46.Ar command 47.Sh DESCRIPTION 48The 49.Nm 50utility enables kernel trace logging for the specified processes. 51Kernel trace data is logged to the file 52.Pa ktrace.out . 53The kernel operations that are traced include system calls, namei 54translations, signal processing, and 55.Tn I/O . 56.Pp 57Once tracing is enabled on a process, trace data will be logged until 58either the process exits or the trace point is cleared. 59A traced process can generate enormous amounts of log data quickly; 60It is strongly suggested that users memorize how to disable tracing before 61attempting to trace a process. 62The following command is sufficient to disable tracing on all user-owned 63processes, and, if executed by root, all processes: 64.Pp 65.Dl \&$ ktrace -C 66.Pp 67The trace file is not human readable; use 68.Xr kdump 1 69to decode it. 70.Pp 71The utility may be used only with a kernel that has been built with the 72.Dq KTRACE 73option in the kernel configuration file. 74.Pp 75The options are: 76.Bl -tag -width indent 77.It Fl a 78Append to the trace file instead of recreating it. 79.It Fl C 80Disable tracing on all user-owned processes, and, if executed by root, all 81processes in the system. 82.It Fl c 83Clear the specified trace points associated with the given file or processes. 84.It Fl d 85Descendants; perform the operation for all current children of the 86designated processes. 87See also the 88.Fl i 89option. 90.It Fl f Ar trfile 91Log trace records to 92.Ar trfile 93instead of 94.Pa ktrace.out . 95.It Fl g Ar pgid 96Enable (disable) tracing on all processes in the process group (only one 97.Fl g 98flag is permitted). 99.It Fl i 100Inherit; pass the trace flags to all future children of the designated 101processes. 102See also the 103.Fl d 104option. 105.It Fl p Ar pid 106Enable (disable) tracing on the indicated process id (only one 107.Fl p 108flag is permitted). 109.It Fl t Ar trstr 110Specify the list of trace points to enable or disable, one per letter. 111If an explicit list is not specified, the default set of trace points is used. 112.Pp 113The following trace points are supported: 114.Pp 115.Bl -tag -width flag -compact 116.It Cm c 117trace system calls 118.It Cm f 119trace page faults 120.It Cm i 121trace 122.Tn I/O 123.It Cm n 124trace namei translations 125.It Cm p 126trace capability check failures 127.It Cm s 128trace signal processing 129.It Cm t 130trace various structures 131.It Cm u 132userland traces generated by 133.Xr utrace 2 134.It Cm w 135context switches 136.It Cm y 137trace 138.Xr sysctl 3 139requests 140.It Cm + 141trace the default set of trace points - 142.Cm c , i , n , p , s , t , u , y 143.El 144.It Ar command 145Execute 146.Ar command 147with the specified trace flags. 148.El 149.Pp 150The 151.Fl p , 152.Fl g , 153and 154.Ar command 155options are mutually exclusive. 156.Sh EXAMPLES 157Run "make", then trace it and any child processes: 158.Dl $ ktrace -i make 159.Pp 160Trace all kernel operations of process id 34: 161.Dl $ ktrace -p 34 162.Pp 163Trace all kernel operations of processes in process group 15 and 164pass the trace flags to all current and future children: 165.Dl $ ktrace -idg 15 166.Pp 167Disable all tracing of process 65: 168.Dl $ ktrace -cp 65 169.Pp 170Disable tracing signals on process 70 and all current children: 171.Dl $ ktrace -t s -cdp 70 172.Pp 173Enable tracing of 174.Tn I/O 175on process 67: 176.Dl $ ktrace -ti -p 67 177.Pp 178Disable all tracing to the file "tracedata": 179.Dl $ ktrace -c -f tracedata 180.Pp 181Disable tracing of all user-owned processes: 182.Dl $ ktrace -C 183.Sh SEE ALSO 184.Xr dtrace 1 , 185.Xr kdump 1 , 186.Xr truss 1 , 187.Xr ktrace 2 , 188.Xr utrace 2 189.Sh HISTORY 190The 191.Nm 192command appeared in 193.Bx 4.4 . 194.Sh BUGS 195Only works if 196.Ar trfile 197is a regular file. 198