mirror of
https://github.com/freebsd/freebsd-src
synced 2024-10-07 00:50:50 +00:00
fa9896e082
Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/
137 lines
3.6 KiB
Groff
137 lines
3.6 KiB
Groff
.\" Copyright (c) 2002 William C. Fenner. 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 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.
|
|
.\"
|
|
.Dd July 3, 2022
|
|
.Dt SOCKATMARK 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm sockatmark
|
|
.Nd determine whether the read pointer is at the OOB mark
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/socket.h
|
|
.Ft int
|
|
.Fn sockatmark "int s"
|
|
.Sh DESCRIPTION
|
|
To find out if the read pointer is currently pointing at
|
|
the mark in the data stream, the
|
|
.Fn sockatmark
|
|
function is provided.
|
|
If
|
|
.Fn sockatmark
|
|
returns 1, the next read will return data
|
|
after the mark.
|
|
Otherwise (assuming out of band data has arrived),
|
|
the next read will provide data sent by the client prior
|
|
to transmission of the out of band signal.
|
|
The routine used
|
|
in the remote login process to flush output on receipt of an
|
|
interrupt or quit signal is shown below.
|
|
It reads the normal data up to the mark (to discard it),
|
|
then reads the out-of-band byte.
|
|
.Bd -literal -offset indent
|
|
#include <sys/socket.h>
|
|
\&...
|
|
oob()
|
|
{
|
|
int out = FWRITE, mark;
|
|
char waste[BUFSIZ];
|
|
|
|
/* flush local terminal output */
|
|
ioctl(1, TIOCFLUSH, (char *)&out);
|
|
for (;;) {
|
|
if ((mark = sockatmark(rem)) < 0) {
|
|
perror("sockatmark");
|
|
break;
|
|
}
|
|
if (mark)
|
|
break;
|
|
(void) read(rem, waste, sizeof (waste));
|
|
}
|
|
if (recv(rem, &mark, 1, MSG_OOB) < 0) {
|
|
perror("recv");
|
|
...
|
|
}
|
|
...
|
|
}
|
|
.Ed
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, the
|
|
.Fn sockatmark
|
|
function returns the value 1 if the read pointer is pointing at
|
|
the OOB mark, 0 if it is not.
|
|
Otherwise the value \-1 is returned
|
|
and the global variable
|
|
.Va errno
|
|
is set to
|
|
indicate the error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn sockatmark
|
|
call fails if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
The
|
|
.Fa s
|
|
argument
|
|
is not a valid descriptor.
|
|
.It Bq Er ENOTTY
|
|
The
|
|
.Fa s
|
|
argument
|
|
is a descriptor for a file, not a socket.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr recv 2 ,
|
|
.Xr send 2
|
|
.Rs
|
|
.%T "An Introductory 4.4BSD Interprocess Communication Tutorial"
|
|
.%A Stuart Sechrest
|
|
.Re
|
|
.%U https://docs.freebsd.org/44doc/psd/20.ipctut/paper.pdf
|
|
.Rs
|
|
.%T "An Advanced 4.4BSD Interprocess Communication Tutorial"
|
|
.%A Samuel J. Leffler
|
|
.%A Robert S. Fabry
|
|
.%A William N. Joy
|
|
.%A Phil Lapsley
|
|
.%A Steve Miller
|
|
.%A Chris Torek
|
|
.%U https://docs.freebsd.org/44doc/psd/21.ipc/paper.pdf
|
|
.Re
|
|
.Sh HISTORY
|
|
The
|
|
.Fn sockatmark
|
|
function was introduced by
|
|
.St -p1003.1-2001 ,
|
|
to standardize the historical
|
|
.Dv SIOCATMARK
|
|
.Xr ioctl 2 .
|
|
The
|
|
.Er ENOTTY
|
|
error instead of the usual
|
|
.Er ENOTSOCK
|
|
is to match the historical behavior of
|
|
.Dv SIOCATMARK .
|