1.\" $NetBSD: setproctitle.3,v 1.18 2003/07/26 19:24:44 salo Exp $ 2.\" 3.\" Copyright (c) 1994, 1995 Christopher G. Demetriou 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed for the 17.\" NetBSD Project. See http://www.NetBSD.org/ for 18.\" information about NetBSD. 19.\" 4. The name of the author may not be used to endorse or promote products 20.\" derived from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32.\" 33.\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>> 34.\" 35.Dd April 13, 1994 36.Dt SETPROCTITLE 3 37.Os 38.Sh NAME 39.Nm setproctitle 40.Nd set process title 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In stdlib.h 45.Ft void 46.Fn setproctitle "const char *fmt" "..." 47.Sh DESCRIPTION 48The 49.Fn setproctitle 50function sets the invoking process's title. 51The process title is set to the last component of the program 52name, followed by a colon and the formatted string specified 53by 54.Va fmt . 55If 56.Va fmt 57is 58.Dv NULL , 59the colon and formatted string are omitted. 60The length of a process title is limited to 2048 bytes. 61.Sh EXAMPLES 62Set the process title to the program name, with no further information: 63.Bd -literal -offset indent 64setproctitle(NULL); 65.Ed 66.Pp 67Set the process title to the program name, an informational string, 68and the process id: 69.Bd -literal -offset indent 70setproctitle("foo! (%d)", getpid()); 71.Ed 72.Sh SEE ALSO 73.Xr ps 1 , 74.Xr w 1 , 75.Xr getprogname 3 , 76.Xr printf 3 77.Sh HISTORY 78The 79.Fn setproctitle 80function first appeared in 81.Nx 1.0 . 82.Sh CAVEATS 83It is important never to pass a string with user-supplied data as a 84format without using 85.Ql %s . 86An attacker can put format specifiers in the string to mangle your stack, 87leading to a possible security hole. 88This holds true even if you have built the string 89.Dq by hand 90using a function like 91.Fn snprintf , 92as the resulting string may still contain user-supplied conversion specifiers 93for later interpolation by 94.Fn setproctitle . 95.Pp 96Always be sure to use the proper secure idiom: 97.Bd -literal -offset indent 98setproctitle("%s", string); 99.Ed 100