xref: /freebsd/lib/libc/gen/setproctitle.3 (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
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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13.\" 3. This work was done expressly for inclusion into FreeBSD.  Other use
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15.\" 4. Absolutely no warranty of function or purpose is made by the author
16.\"    Peter Wemm.
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20.\" $FreeBSD$
21.\"
22.\" The following requests are required for all man pages.
23.Dd December 16, 1995
24.Dt SETPROCTITLE 3
25.Os
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.
72Other methods of causing the
73.Xr ps 1
74command line to change, including copying over the argv[0] string are
75also implicitly non-portable.
76It is preferable to use an operating system
77supplied
78.Fn setproctitle
79if present.
80.Pp
81Unfortunately, it is possible that there are other calling conventions
82to other versions of
83.Fn setproctitle ,
84although none have been found by the author as yet.
85This is believed to be
86the predominant convention.
87.Pp
88It is thought that the implementation is compatible with other systems,
89including
90.Nx
91and
92.Bsx .
93.Sh HISTORY
94The
95.Fn setproctitle
96function
97first appeared in
98.Fx 2.2 .
99Other operating systems have
100similar functions.
101.Sh AUTHORS
102.An -nosplit
103.An Peter Wemm Aq Mt peter@FreeBSD.org
104stole the idea from the
105.Sy "Sendmail 8.7.3"
106source code by
107.An Eric Allman Aq Mt eric@sendmail.org .
108.Sh BUGS
109Never pass a string with user-supplied data as a format without using
110.Ql %s .
111An attacker can put format specifiers in the string to mangle your stack,
112leading to a possible security hole.
113This holds true even if the string was built using a function like
114.Fn snprintf ,
115as the resulting string may still contain user-supplied conversion specifiers
116for later interpolation by
117.Fn setproctitle .
118.Pp
119Always use the proper secure idiom:
120.Pp
121.Dl setproctitle("%s", string);
122