svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
ng_tty(4)
NG_TTY(4) BSD Kernel Interfaces Manual NG_TTY(4)
NAME
ng_tty — netgraph node type that is also a TTY hook
SYNOPSIS
#include <sys/types.h>
#include <sys/ttycom.h>
#include <netgraph/ng_tty.h>
DESCRIPTION
The tty node type is both a netgraph node type and a TTY hook.
The node has a single hook called hook. Incoming bytes received on the
tty device are sent out on this hook, and frames received on hook are
transmitted out on the tty device. No modification to the data is per‐
formed in either direction. While the hook is installed on a tty, the
normal read and write operations are unavailable, returning EIO.
Incoming data is delivered directly to ng_tty via the tty bypass hook as
a buffer pointer and length, this is converted to a mbuf and passed to
the peer.
The node supports an optional “hot character”. If the driver can not
deliver data directly to the tty bypass hook then each character is input
one at a time. If set to non-zero and bypass mode is unavailable, incom‐
ing data from the tty device is queued until this character is seen.
This avoids sending lots of mbufs containing a small number of bytes, but
introduces potentially infinite latency. The default hot character is
0x7e, consistent with hook being connected to a ng_async(4) type node.
The hot character has no effect on the transmission of data.
HOOKS
This node type supports the following hooks:
hook tty(4) serial data contained in mbuf structures, with arbitrary
inter-frame boundaries.
CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
NGM_TTY_SET_HOTCHAR
This command takes an integer argument and sets the hot character
from the lower 8 bits. A hot character of zero disables queueing,
so that all received data is forwarded immediately.
NGM_TTY_GET_HOTCHAR
Returns an integer containing the current hot character in the lower
eight bits.
NGM_TTY_SET_TTY
This command takes integer process ID and file descriptor of open
tty and registers the tty hooks.
SHUTDOWN
This node shuts down when the corresponding device is closed.
SEE ALSO
ioctl(2), netgraph(4), ng_async(4), tty(4), ngctl(8)
HISTORY
The ng_tty node type was implemented in FreeBSD 4.0.
AUTHORS
Archie Cobbs <archie@FreeBSD.org>
Andrew Thompson <thompsa@FreeBSD.org>
BUGS
The serial driver code also has a notion of a “hot character”. Unfortu‐
nately, this value is statically defined in terms of the line discipline
and cannot be changed. Therefore, if a hot character other than 0x7e
(the default) is set for the ng_tty node, the node has no way to convey
this information to the serial driver, and sub-optimal performance may
result.
BSD December 25, 2008 BSD