136 lines
4.0 KiB
Groff
136 lines
4.0 KiB
Groff
.\" $NetBSD: getpeername.2,v 1.18 2003/08/07 16:43:58 agc Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. 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.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
|
|
.\"
|
|
.\" @(#)getpeername.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd August 11, 2002
|
|
.Dt GETPEERNAME 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm getpeername
|
|
.Nd get name of connected peer
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/socket.h
|
|
.Ft int
|
|
.Fn getpeername "int s" "struct sockaddr * restrict name" "socklen_t * restrict namelen"
|
|
.Sh DESCRIPTION
|
|
.Fn getpeername
|
|
returns the name of the peer connected to
|
|
socket
|
|
.Fa s .
|
|
One common use occurs when a process inherits an open socket, such as
|
|
TCP servers forked from
|
|
.Xr inetd 8 .
|
|
In this scenario,
|
|
.Fn getpeername
|
|
is used to determine the connecting client's IP address.
|
|
.Pp
|
|
.Fn getpeername
|
|
takes three parameters:
|
|
.Pp
|
|
.Fa s
|
|
Contains the file descriptor of the socket whose peer should be looked up.
|
|
.Pp
|
|
.Fa name
|
|
Points to a
|
|
.Li sockaddr
|
|
structure that will hold the address information for the connected peer.
|
|
Normal use requires one to use a structure
|
|
specific to the protocol family in use, such as
|
|
.Li sockaddr_in
|
|
(IPv4) or
|
|
.Li sockaddr_in6
|
|
(IPv6), cast to a (struct sockaddr *).
|
|
.Pp
|
|
For greater portability, especially with the newer protocol families, the new
|
|
.Li struct sockaddr_storage
|
|
should be used.
|
|
.Li sockaddr_storage
|
|
is large enough to hold any of the other sockaddr_* variants.
|
|
On return, it can be cast to the correct sockaddr type,
|
|
based the protocol family contained in its ss_family field.
|
|
.Pp
|
|
.Fa namelen
|
|
indicates the amount of space pointed to by
|
|
.Fa name ,
|
|
in bytes.
|
|
.Pp
|
|
If address information for the local end of the socket is required, the
|
|
.Xr getsockname 2
|
|
function should be used instead.
|
|
.Pp
|
|
If
|
|
.Fa name
|
|
does not point to enough space to hold the entire socket address, the
|
|
result will be truncated to
|
|
.Fa namelen
|
|
bytes.
|
|
.Sh RETURN VALUES
|
|
If the call succeeds, a 0 is returned and
|
|
.Fa namelen
|
|
is set to the actual size of the socket address returned in
|
|
.Fa name .
|
|
Otherwise,
|
|
.Va errno
|
|
is set and a value of \-1 is returned.
|
|
.Sh ERRORS
|
|
The call succeeds unless:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
The argument
|
|
.Fa s
|
|
is not a valid descriptor.
|
|
.It Bq Er ENOTSOCK
|
|
The argument
|
|
.Fa s
|
|
is a file, not a socket.
|
|
.It Bq Er ENOTCONN
|
|
The socket is not connected.
|
|
.It Bq Er ENOBUFS
|
|
Insufficient resources were available in the system
|
|
to perform the operation.
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa name
|
|
parameter points to memory not in a valid part of the
|
|
process address space.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr accept 2 ,
|
|
.Xr bind 2 ,
|
|
.Xr getsockname 2 ,
|
|
.Xr socket 2
|
|
.Sh HISTORY
|
|
The
|
|
.Fn getpeername
|
|
function call appeared in
|
|
.Bx 4.2 .
|