- Uniformly use .In for header file references.
[dragonfly.git] / lib / libutil / realhostname_sa.3
CommitLineData
984263bc
MD
1.\" Copyright (C) 1995, 1996, 1997, 1998, 1999, and 2000 WIDE Project.
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\" notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\" notice, this list of conditions and the following disclaimer in the
11.\" documentation and/or other materials provided with the distribution.
12.\" 3. Neither the name of the project nor the names of its contributors
13.\" may be used to endorse or promote products derived from this software
14.\" without specific prior written permission.
15.\"
16.\" THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26.\" SUCH DAMAGE.
27.\"
28.\" Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
29.\" All rights reserved.
30.\"
31.\" Redistribution and use in source and binary forms, with or without
32.\" modification, are permitted provided that the following conditions
33.\" are met:
34.\" 1. Redistributions of source code must retain the above copyright
35.\" notice, this list of conditions and the following disclaimer.
36.\" 2. Redistributions in binary form must reproduce the above copyright
37.\" notice, this list of conditions and the following disclaimer in the
38.\" documentation and/or other materials provided with the distribution.
39.\"
40.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
41.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50.\" SUCH DAMAGE.
51.\"
52.\" $FreeBSD: src/lib/libutil/realhostname_sa.3,v 1.2.2.3 2001/12/17 10:08:32 ru Exp $
44cb301e 53.\" $DragonFly: src/lib/libutil/realhostname_sa.3,v 1.3 2006/05/26 19:39:38 swildner Exp $
984263bc
MD
54.\"
55.Dd January 11, 2000
56.Os
57.Dt REALHOSTNAME_SA 3
58.Sh NAME
59.Nm realhostname_sa
60.Nd "convert an struct sockaddr to the real host name"
61.Sh LIBRARY
62.Lb libutil
63.Sh SYNOPSIS
64.In sys/types.h
65.In netinet/in.h
66.In libutil.h
67.Ft int
68.Fn realhostname_sa "char *host" "size_t hsize" "struct sockaddr *addr" "int addrlen"
69.Sh DESCRIPTION
70The function
71.Fn realhostname_sa
72converts
73.Ar addr
74to the corresponding host name. This is done by resolving
75.Ar addr
76to a host name and then ensuring that the host name resolves
77back to
78.Ar addr .
79.Pp
80.Ar host
81must point to a buffer of at least
82.Ar hsize
83bytes, and will always be written to by this function.
84.Pp
85If the name resolution doesn't work both ways or if the host name is longer
86than
87.Ar hsize
88bytes,
89.Xr getnameinfo 3
90with NI_NUMERICHOST specified, is used to convert
91.Ar addr
92to an ASCII form.
93.Pp
94If the string written to
95.Ar host
96is
97.Ar hsize
98bytes long,
99.Ar host
100will not be NUL terminated.
101.Sh RETURN VALUES
102.Fn realhostname_sa
103will return one of the following constants which are defined in
44cb301e 104.In libutil.h :
984263bc
MD
105.Pp
106.Bl -tag -width XXX -offset XXX
107.It Li HOSTNAME_FOUND
108A valid host name was found.
109.It Li HOSTNAME_INCORRECTNAME
110A host name was found, but it did not resolve back to the passed
111.Ar ip .
112.Ar host
113now contains the numeric value of
114.Ar ip .
115.It Li HOSTNAME_INVALIDADDR
116.Ar ip
117could not be resolved.
118.Ar host
119now contains the numeric value of
120.Ar ip .
121.It Li HOSTNAME_INVALIDNAME
122A host name was found, but it could not be resolved back to any ip number.
123.Ar host
124now contains the numeric value of
125.Ar ip .
126.El
127.Sh SEE ALSO
128.Xr getaddrinfo 3 ,
129.Xr getnameinfo 3 ,
130.Xr realhostname 3