c2e3c52e0d
This change allows creating file descriptors with close-on-exec set in some situations. SOCK_CLOEXEC and SOCK_NONBLOCK can be OR'ed in socket() and socketpair()'s type parameter, and MSG_CMSG_CLOEXEC to recvmsg() makes file descriptors (SCM_RIGHTS) atomically close-on-exec. The numerical values for SOCK_CLOEXEC and SOCK_NONBLOCK are as in NetBSD. MSG_CMSG_CLOEXEC is the first free bit for MSG_*. The SOCK_* flags are not passed to MAC because this may cause incorrect failures and can be done later via fcntl() anyway. On the other hand, audit is expected to cope with the new flags. For MSG_CMSG_CLOEXEC, unp_externalize() is extended to take a flags argument. Reviewed by: kib
101 lines
3.0 KiB
Groff
101 lines
3.0 KiB
Groff
.\" 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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.\" 4. 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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.\" @(#)socketpair.2 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd March 19, 2013
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.Dt SOCKETPAIR 2
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.Os
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.Sh NAME
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.Nm socketpair
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.Nd create a pair of connected sockets
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/socket.h
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.Ft int
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.Fn socketpair "int d" "int type" "int protocol" "int *sv"
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.Sh DESCRIPTION
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The
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.Fn socketpair
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system call creates an unnamed pair of connected sockets in
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the specified domain
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.Fa d ,
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of the specified
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.Fa type ,
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and using the optionally specified
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.Fa protocol .
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The descriptors used in referencing the new sockets
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are returned in
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.Fa sv Ns [0]
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and
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.Fa sv Ns [1] .
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The two sockets are indistinguishable.
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.Pp
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The
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.Dv SOCK_CLOEXEC
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and
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.Dv SOCK_NONBLOCK
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flags in the
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.Fa type
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argument apply to both descriptors.
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.Sh RETURN VALUES
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.Rv -std socketpair
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.Sh ERRORS
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The call succeeds unless:
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.Bl -tag -width Er
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.It Bq Er EMFILE
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Too many descriptors are in use by this process.
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.It Bq Er EAFNOSUPPORT
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The specified address family is not supported on this machine.
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.It Bq Er EPROTONOSUPPORT
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The specified protocol is not supported on this machine.
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.It Bq Er EOPNOTSUPP
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The specified protocol does not support creation of socket pairs.
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.It Bq Er EFAULT
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The address
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.Fa sv
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does not specify a valid part of the
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process address space.
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.El
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.Sh SEE ALSO
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.Xr pipe 2 ,
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.Xr read 2 ,
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.Xr socket 2 ,
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.Xr write 2
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.Sh HISTORY
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The
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.Fn socketpair
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system call appeared in
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.Bx 4.2 .
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.Sh BUGS
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This call is currently implemented only for the
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.Ux
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domain.
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