xref: /freebsd/lib/libc/gen/setproctitle.3 (revision 7ebcc426efefea9cd16ac6f565e72030c608f7a4)
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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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.Fd #include <sys/types.h>
31.Fd #include <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
68.Fn setproctitle
69is implicitly non-standard.  Other methods of causing the
70.Xr ps 1
71command line to change, including copying over the argv[0] string are
72also implicitly non-portable.  It is preferable to use an operating system
73supplied
74.Fn setproctitle
75if present.
76.Pp
77Unfortunately, it is possible that there are other calling conventions
78to other versions of
79.Fn setproctitle ,
80although none have been found by the author as yet.  This is believed to be
81the predominant convention.
82.Pp
83It is thought that the implementation is compatible with other systems,
84including
85.Nx
86and
87.Tn BSD/OS .
88.Sh HISTORY
89.Fn setproctitle
90first appeared in
91.Fx 2.2 .
92Other operating systems have
93similar functions.
94.Sh AUTHORS
95.An -nosplit
96.An Peter Wemm Aq peter@FreeBSD.org
97stole the idea from the
98.Sy "Sendmail 8.7.3"
99source code by
100.An Eric Allman Aq eric@sendmail.org .
101.Sh BUGS
102Never pass a string with user-supplied data as a format without using
103.Ql %s .
104An attacker can put format specifiers in the string to mangle your stack,
105leading to a possible security hole.
106This holds true even if the string was built using a function like
107.Fn snprintf ,
108as the resulting string may still contain user-supplied conversion specifiers
109for later interpolation by
110.Fn setproctitle .
111.Pp
112Always use the proper secure idiom:
113.Pp
114.Dl setproctitle("%s", string);
115