NetBSD/lib/libc/gen/setproctitle.3

.\" $NetBSD: setproctitle.3,v 1.18 2003/07/26 19:24:44 salo Exp $
.\"
.\" Copyright (c) 1994, 1995 Christopher G. Demetriou
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"          This product includes software developed for the
.\"          NetBSD Project.  See http://www.NetBSD.org/ for
.\"          information about NetBSD.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
.\"
.Dd April 13, 1994
.Dt SETPROCTITLE 3
.Os
.Sh NAME
.Nm setproctitle
.Nd set process title
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft void
.Fn setproctitle "const char *fmt" "..."
.Sh DESCRIPTION
The
.Fn setproctitle
function sets the invoking process's title.
The process title is set to the last component of the program
name, followed by a colon and the formatted string specified
by
.Va fmt .
If
.Va fmt
is
.Dv NULL ,
the colon and formatted string are omitted.
The length of a process title is limited to 2048 bytes.
.Sh EXAMPLES
Set the process title to the program name, with no further information:
.Bd -literal -offset indent
setproctitle(NULL);
.Ed
.Pp
Set the process title to the program name, an informational string,
and the process id:
.Bd -literal -offset indent
setproctitle("foo! (%d)", getpid());
.Ed
.Sh SEE ALSO
.Xr ps 1 ,
.Xr w 1 ,
.Xr getprogname 3 ,
.Xr printf 3
.Sh HISTORY
The
.Fn setproctitle
function first appeared in
.Nx 1.0 .
.Sh CAVEATS
It is important never to pass a string with user-supplied data as a
format without using
.Ql %s .
An attacker can put format specifiers in the string to mangle your stack,
leading to a possible security hole.
This holds true even if you have built the string
.Dq by hand
using a function like
.Fn snprintf ,
as the resulting string may still contain user-supplied conversion specifiers
for later interpolation by
.Fn setproctitle .
.Pp
Always be sure to use the proper secure idiom:
.Bd -literal -offset indent
setproctitle("%s", string);
.Ed