bc89b58def
Reviewed by: bcr (mentor) Approved by: bcr (mentor) MFC after: 7 days Differential Revision: https://reviews.freebsd.org/D24795
108 lines
3.0 KiB
Groff
108 lines
3.0 KiB
Groff
.\" Copyright (c) 1999 Brian Somers <brian@Awfulhak.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd April 6, 1999
|
|
.Dt REALHOSTNAME 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm realhostname
|
|
.Nd "convert an IP number to the real host name"
|
|
.Sh LIBRARY
|
|
.Lb libutil
|
|
.Sh SYNOPSIS
|
|
.In libutil.h
|
|
.Ft int
|
|
.Fn realhostname "char *host" "size_t hsize" "const struct in_addr *ip"
|
|
.Sh DESCRIPTION
|
|
The function
|
|
.Fn realhostname
|
|
converts
|
|
.Ar ip
|
|
to the corresponding host name.
|
|
This is done by resolving
|
|
.Ar ip
|
|
to a host name and then ensuring that the host name resolves
|
|
back to
|
|
.Ar ip .
|
|
.Pp
|
|
.Ar host
|
|
must point to a buffer of at least
|
|
.Ar hsize
|
|
bytes, and will always be written to by this function.
|
|
.Pp
|
|
If the name resolution does not work both ways or if the host name is longer
|
|
than
|
|
.Ar hsize
|
|
bytes,
|
|
.Xr inet_ntoa 3
|
|
is used to convert
|
|
.Ar ip
|
|
to an ASCII form.
|
|
.Pp
|
|
If the string written to
|
|
.Ar host
|
|
is
|
|
.Ar hsize
|
|
bytes long,
|
|
.Ar host
|
|
will not be NUL terminated.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn realhostname
|
|
function will return one of the following constants which are defined in
|
|
.In libutil.h :
|
|
.Bl -tag -width XXX -offset XXX
|
|
.It Li HOSTNAME_FOUND
|
|
A valid host name was found.
|
|
.It Li HOSTNAME_INCORRECTNAME
|
|
A host name was found, but it did not resolve back to the passed
|
|
.Ar ip .
|
|
.Ar host
|
|
now contains the numeric value of
|
|
.Ar ip .
|
|
.It Li HOSTNAME_INVALIDADDR
|
|
.Ar ip
|
|
could not be resolved.
|
|
.Ar host
|
|
now contains the numeric value of
|
|
.Ar ip .
|
|
.It Li HOSTNAME_INVALIDNAME
|
|
A host name was found, but it could not be resolved back to any ip number.
|
|
.Ar host
|
|
now contains the numeric value of
|
|
.Ar ip .
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr gethostbyaddr 3 ,
|
|
.Xr gethostbyname 3 ,
|
|
.Xr inet_ntoa 3 ,
|
|
.Xr realhostname_sa 3
|
|
.Sh HISTORY
|
|
The
|
|
.Fn realhostname
|
|
function first appeared in
|
|
.Fx 3.2 .
|