xref: /freebsd/lib/libc/gen/setproctitle.3 (revision 95f4226b2755f1600e3bf4e32e8aa0db0886c280)
1.\" Copyright (c) 1995 Peter Wemm <peter@freebsd.org>
2.\" All rights reserved.
3.\"
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5.\" modification, is permitted provided that the following conditions
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9.\"    this list of conditions, and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\"    notice, this list of conditions and the following disclaimer in the
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13.\" 3. This work was done expressly for inclusion into FreeBSD.  Other use
14.\"    is permitted provided this notation is included.
15.\" 4. Absolutely no warranty of function or purpose is made by the author
16.\"    Peter Wemm.
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18.\"    conditions are met.
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20.\" $FreeBSD$
21.\"
22.\" The following requests are required for all man pages.
23.Dd December 16, 1995
24.Os
25.Dt SETPROCTITLE 3
26.Sh NAME
27.Nm setproctitle
28.Nd set process title
29.Sh SYNOPSIS
30.In sys/types.h
31.In unistd.h
32.Ft void
33.Fn setproctitle "const char *fmt" "..."
34.Sh DESCRIPTION
35The
36.Fn setproctitle
37library routine sets the process title that appears on the
38.Xr ps 1
39command.
40.Pp
41The title is set from the executable's name, followed by the
42result of a
43.Xr printf 3
44style expansion of the arguments as specified by the
45.Va fmt
46argument.
47If the
48.Va fmt
49argument begins with a
50.Dq -
51character, the executable's name is skipped.
52.Pp
53If
54.Va fmt
55is NULL, the process title is restored.
56.Sh EXAMPLES
57To set the title on a daemon to indicate its activity:
58.Bd -literal -offset indent
59setproctitle("talking to %s", inet_ntoa(addr));
60.Ed
61.Sh SEE ALSO
62.Xr ps 1 ,
63.Xr w 1 ,
64.Xr kvm 3 ,
65.Xr kvm_getargv 3 ,
66.Xr printf 3
67.Sh STANDARDS
68The
69.Fn setproctitle
70function
71is implicitly non-standard.  Other methods of causing the
72.Xr ps 1
73command line to change, including copying over the argv[0] string are
74also implicitly non-portable.  It is preferable to use an operating system
75supplied
76.Fn setproctitle
77if present.
78.Pp
79Unfortunately, it is possible that there are other calling conventions
80to other versions of
81.Fn setproctitle ,
82although none have been found by the author as yet.  This is believed to be
83the predominant convention.
84.Pp
85It is thought that the implementation is compatible with other systems,
86including
87.Nx
88and
89.Bsx .
90.Sh HISTORY
91The
92.Fn setproctitle
93function
94first appeared in
95.Fx 2.2 .
96Other operating systems have
97similar functions.
98.Sh AUTHORS
99.An -nosplit
100.An Peter Wemm Aq peter@FreeBSD.org
101stole the idea from the
102.Sy "Sendmail 8.7.3"
103source code by
104.An Eric Allman Aq eric@sendmail.org .
105.Sh BUGS
106Never pass a string with user-supplied data as a format without using
107.Ql %s .
108An attacker can put format specifiers in the string to mangle your stack,
109leading to a possible security hole.
110This holds true even if the string was built using a function like
111.Fn snprintf ,
112as the resulting string may still contain user-supplied conversion specifiers
113for later interpolation by
114.Fn setproctitle .
115.Pp
116Always use the proper secure idiom:
117.Pp
118.Dl setproctitle("%s", string);
119