1.\" Copyright (c) 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.2 8.1 (Berkeley) 6/4/93 33.\" 34.Dd June 4, 1993 35.Dt KTRACE 2 36.Os BSD 4 37.Sh NAME 38.Nm ktrace 39.Nd process tracing 40.Sh SYNOPSIS 41.Fd #include <sys/types.h> 42.Fd #include <sys/ktrace.h> 43.Ft int 44.Fn ktrace "const char *tracefile" "int ops" "int trpoints" "int pid" 45.Sh DESCRIPTION 46The 47.Fn ktrace 48function enables or disables tracing of one or more processes. 49Users may only trace their own processes. 50Only the super-user can trace setuid or setgid programs. 51.Pp 52The 53.Ar tracefile 54gives the pathname of the file to be used for tracing. 55The file must exist and be writable by the calling process. 56All trace records are always appended to the file, 57so the file must be truncated to zero length to discard 58previous trace data. 59If tracing points are being disabled (see KTROP_CLEAR below), 60.Ar tracefile 61may be NULL. 62.Pp 63The 64.Nm ops 65parameter specifies the requested ktrace operation. 66The defined operations are: 67.Bl -column KTRFLAG_DESCENDXXX -offset indent 68.It KTROP_SET Enable trace points specified in Ar trpoints . 69.It KTROP_CLEAR Disable trace points specified in Ar trpoints . 70.It KTROP_CLEARFILE Stop all tracing. 71.It KTRFLAG_DESCEND The tracing change should apply to the 72specified process and all its current children. 73.El 74.Pp 75The 76.Nm trpoints 77parameter specifies the trace points of interest. 78The defined trace points are: 79.Bl -column KTRFAC_SYSCALLXXX -offset indent 80.It KTRFAC_SYSCALL Trace system calls. 81.It KTRFAC_SYSRET Trace return values from system calls. 82.It KTRFAC_NAMEI Trace name lookup operations. 83.It KTRFAC_GENIO Trace all I/O (note that this option can 84generate much output). 85.It KTRFAC_PSIG Trace posted signals. 86.It KTRFAC_CSW Trace context switch points. 87.It KTRFAC_INHERIT Inherit tracing to future children. 88.El 89.Pp 90Each tracing event outputs a record composed of a generic header 91followed by a trace point specific structure. 92The generic header is: 93.Bd -literal 94struct ktr_header { 95 int ktr_len; /* length of buf */ 96 short ktr_type; /* trace record type */ 97 pid_t ktr_pid; /* process id */ 98 char ktr_comm[MAXCOMLEN+1]; /* command name */ 99 struct timeval ktr_time; /* timestamp */ 100 caddr_t ktr_buf; 101}; 102.Ed 103.Pp 104The 105.Nm ktr_len 106field specifies the length of the 107.Nm ktr_type 108data that follows this header. 109The 110.Nm ktr_pid 111and 112.Nm ktr_comm 113fields specify the process and command generating the record. 114The 115.Nm ktr_time 116field gives the time (with microsecond resolution) 117that the record was generated. 118The 119.Nm ktr_buf 120is an internal kernel pointer and is not useful. 121.Pp 122The generic header is followed by 123.Nm ktr_len 124bytes of a 125.Nm ktr_type 126record. 127The type specific records are defined in the 128.Pa <sys/ktrace.h> 129include file. 130.Sh RETURN VALUES 131On successful completion a value of 0 is returned. 132Otherwise, a value of -1 is returned and 133.Va errno 134is set to show the error. 135.Sh ERRORS 136.Fn Ktrace 137will fail if: 138.Bl -tag -width ENAMETOOLONGAA 139.It Bq Er ENOTDIR 140A component of the path prefix is not a directory. 141.It Bq Er EINVAL 142The pathname contains a character with the high-order bit set. 143.It Bq Er ENAMETOOLONG 144A component of a pathname exceeded 255 characters, 145or an entire path name exceeded 1023 characters. 146.It Bq Er ENOENT 147The named tracefile does not exist. 148.It Bq Er EACCES 149Search permission is denied for a component of the path prefix. 150.It Bq Er ELOOP 151Too many symbolic links were encountered in translating the pathname. 152.It Bq Er EIO 153An I/O error occurred while reading from or writing to the file system. 154.El 155.Sh SEE ALSO 156.Xr ktrace 1 , 157.Xr kdump 1 158.Sh HISTORY 159A 160.Nm ktrace 161function call first appeared in 162.Bx 4.4 . 163