148 lines
4.1 KiB
Groff
148 lines
4.1 KiB
Groff
.\" $OpenBSD: getnetent.3,v 1.19 2019/08/30 20:20:51 jmc Exp $
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.\"
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.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd $Mdocdate: August 30 2019 $
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.Dt GETNETENT 3
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.Os
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.Sh NAME
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.Nm getnetent ,
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.Nm getnetbyaddr ,
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.Nm getnetbyname ,
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.Nm setnetent ,
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.Nm endnetent
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.Nd get network entry
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.Sh SYNOPSIS
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.In netdb.h
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.Ft struct netent *
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.Fn getnetent "void"
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.Ft struct netent *
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.Fn getnetbyname "const char *name"
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.Ft struct netent *
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.Fn getnetbyaddr "in_addr_t net" "int type"
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.Ft void
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.Fn setnetent "int stayopen"
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.Ft void
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.Fn endnetent "void"
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.Sh DESCRIPTION
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The
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.Fn getnetbyname
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and
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.Fn getnetbyaddr
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functions return a pointer to an object with the following structure:
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.Bd -literal -offset indent
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struct netent {
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char *n_name; /* official name of net */
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char **n_aliases; /* alias list */
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int n_addrtype; /* net number type */
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in_addr_t n_net; /* net number */
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};
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.Ed
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.Pp
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The members of this structure are:
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.Bl -tag -width n_addrtype
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.It Fa n_name
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The official name of the network.
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.It Fa n_aliases
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A null-terminated list of alternate names for the network.
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.It Fa n_addrtype
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The type of the network number returned; it is always
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.Dv AF_INET .
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.It Fa n_net
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The network number.
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Network numbers are returned in machine byte order.
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.El
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.Pp
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On
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.Ox ,
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these legacy functions perform a lookup in a similar fashion as
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.Xr gethostbyname 3
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and
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.Xr gethostbyaddr 3 ,
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respectively.
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On other systems, they may use a separate network database file,
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.Pa /etc/networks .
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.Pp
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In contrast to
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.Xr gethostbyaddr 3 ,
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the
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.Fa net
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argument is expected in machine byte order.
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.Pp
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The
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.Fn setnetent ,
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.Fn getnetent ,
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and
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.Fn endnetent
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functions are deprecated and no longer have any effect.
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They could be used in the past to iterate over entries in the former file
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.Pa /etc/networks .
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.Sh RETURN VALUES
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The
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.Fn getnetbyaddr
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and
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.Fn getnetbyname
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functions return
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.Dv NULL
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if the requested entry is not found.
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.Pp
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The
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.Fn getnetent
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function always returns
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.Dv NULL .
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.Sh FILES
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.Bl -tag -width /etc/hosts -compact
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.It Pa /etc/hosts
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The local host and network name database.
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.El
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.Sh SEE ALSO
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.Xr getaddrinfo 3 ,
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.Xr gethostbyname 3 ,
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.Xr getnameinfo 3 ,
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.Xr res_init 3 ,
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.Xr hosts 5
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.Sh STANDARDS
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These functions conform to
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.St -p1003.1-2008 .
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.Sh HISTORY
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The
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.Fn getnetent ,
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.Fn getnetbyaddr ,
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.Fn getnetbyname ,
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.Fn setnetent ,
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and
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.Fn endnetent
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functions appeared in
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.Bx 4.2 .
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.Sh BUGS
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The data space used by these functions is static; if future use
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requires the data, it should be copied before any subsequent calls
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to these functions overwrite it.
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Only Internet network numbers are currently understood.
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Expecting network numbers to fit in no more than 32 bits is naive.
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