freebsd/usr.sbin/dconschat/dconschat.8

.\" Copyright (c) 2003 Hidetoshi Shimokawa
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
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.\" $FreeBSD$
.\"
.\"
.Dd February 11, 2003
.Dt DCONSCHAT 8
.Os
.Sh NAME
.Nm dconschat
.Nd user interface to
.Xr dcons 4
.Sh SYNOPSIS
.Nm
.Op Fl brvwRT1
.Op Fl e Ar escape-char
.Op Fl h Ar hz
.Op Fl C Ar console_port
.Op Fl G Ar gdb_port
.Op Fl M Ar core
.Op Fl N Ar system
.Nm
.Op Fl brvwR1
.Op Fl h Ar hz
.Op Fl C Ar console_port
.Op Fl G Ar gdb_port
.Op Fl a Ar address
.Op Fl u Ar bus_num
.Fl t Ar target_eui64
.Sh DESCRIPTION
The
.Nm
utility is designed to provide a way for users to access
.Xr dcons 4
(dumb console device) on a local or remote system.
The
.Nm
utility interacts with
.Xr dcons 4
using
.Xr kvm 3
or
.Xr firewire 4 ,
and interacts with the user over TTY or TCP/IP.
To access remote
.Xr dcons 4
using
.Xr firewire 4 ,
you have to specify target EUI64 address using the
.Fl t
option. Physical DMA should be enabled on the target machine for access
via FireWire.
.Pp
The
.Nm
utility and the
.Xr dcons 4
driver communicate using 2 ports, one for the console port and another
for remote
.Xr gdb 1
port.
Users are supposed to access
.Nm
using TTY,
.Xr telnet 1
and
.Xr gdb 1 .
You can specify listen ports for console and
.Xr gdb 1
port using the
.Fl C
and
.Fl G
options respectively.
The port number 0 has special meaning that
current TTY (stdin/stdout) is used instead of TCP/IP.
A negative port number will disable the port.
By analogy with
.Xr pty 4
device, the
.Xr dcons 4
acts as a slave device and
.Nm
acts as a master device with
.Xr telnetd 8 .
.Pp
Typed characters are normally transmitted directly to
.Xr dcons 4 .
A escape character (the default is
.Ql ~
) appearing as the first character of a line is an escape signal; the
following are recognized:
.Bl -tag -width ident
.It Ic ~.
Drop the connection and exit.
.It Ic ~^G
Invoke kgdb on the terminal on which dconschat is running.
.It Ic ~^R
Reset the target over FireWire if a reset address is registered in Configuration ROM.
.It Ic ~^Z
Suspend the dconschat process.
.El
.Pp
The following options are supported.
.Bl -tag -width indent
.It Fl b
Translate Ctrl-C to ALT_BREAK (CR +
.Ql ~
+ Ctrl-B) on
.Xr gdb 1
port.
.It Fl r
Replay old buffer on connection.
.It Fl v
Verbose debug output.
Multiple
.Fl v
options increase verbosity.
.It Fl w
Listen on a wildcard address rather than localhost.
.It Fl R
Read-only.
Do not write anything to the
.Xr dcons 4
buffer.
.It Fl T
Enable ad-hoc workaround for the TELNET protocol to
remove unnecessary byte sequences.
It should be set when you access
.Nm
using
.Xr telnet 1 .
.It Fl 1
One-shot.
Read available buffer, then exit.
This implies the
.Fl r
option.
.It Fl e Ar escape-char
Specify escape character.
The default is '~'.
.It Fl h Ar hz
Specify polling rate.
The default value is 100.
.It Fl C Ar console_port
Specify the console port.
The default value is 0 (stdin/stdout).
.It Fl G Ar gdb_port
Specify
.Xr gdb 1
port.
The default value is \-1 (disabled).
.It Fl M Ar core
Specify core file.
.It Fl N Ar system
Specify system file such as
.Pa /boot/kernel/kernel .
.It Fl t Ar target_eui64
Specify the 64-bit extended unique identifier of the target,
and use FireWire to access remote
.Xr dcons 4 .
.It Fl a Ar address
Specify the physical I/O address of the
.Xr dcons 4
buffer.
See
.Xr dcons 4
for details.
If this option is not specified,
.Nm
tries to get the address from the Configuration ROM on the target.
You are supposed to enable
.Xr dcons_crom 4
on the target to omit this option.
.It Fl u Ar bus_num
Specify FireWire bus number.
The default is 0.
.El
.Sh FILES
.Bl -tag -width indent -compact
.It Pa /dev/fwmem0.0
.It Pa /dev/mem
.It Pa /dev/kmem
.El
.Sh EXAMPLES
To use
.Nm
with FireWire for remote
.Xr dcons 4 ,
you have to specify the EUI64 of the target.
You can obtain EUI64 by running
.Xr fwcontrol 8
without options.
The first EUI64 is of the host running
.Xr fwcontrol 8
and others on the bus follow.
.Bd -literal -offset indent
# fwcontrol
2 devices (info_len=2)
node           EUI64          status
   1  77-66-55-44-33-22-11-00      0
   0  00-11-22-33-44-55-66-77      1
.Ed
.Pp
The EUI64 does not change unless you change the hardware
as the ethernet address.
.Pp
Now we can run
.Nm .
.Bd -literal -offset indent
# dconschat -br -G 12345 -t 00-11-22-33-44-55-66-77
.Ed
.Pp
You will get console output of the target and login prompt if a
.Xr getty 8
is running on
.Xr dcons 4 .
You can break to DDB with ALT_BREAK (CR +
.Ql ~
+ Ctrl-B)
if
.Dv DDB
and
.Dv ALT_BREAK_TO_DEBUGGER
are enabled in the target kernel.
To quit the session, type CR +
.Ql ~
+
.Ql \&.
in the console port.
.Pp
Using
.Xr gdb 1
port is almost the same as remote
.Xr gdb 1
over serial line except
using TCP/IP instead of
.Pa /dev/cu* .
See
.Sx "On-line Kernel Debugging Using Remote GDB"
section of
.%T "The FreeBSD Developers Handbook"
and
.Xr gdb 4
for details.
.Bd -literal -offset indent
% gdb -k kernel.debug
(kgdb) target remote :12345
.Ed
.Pp
Once
.Xr gdb 1
is attached and you specified the
.Fl b
option to
.Nm ,
typing Ctrl-C in
.Xr gdb 1
causes a break to debugger.
.Pp
The following command gets the console log from the crash dump:
.Bd -literal -offset indent
# dconschat -1 -M vmcore.0 -N kernel.0
.Ed
.Pp
If you want access to the console using
.Xr telnet 1 ,
try the following:
.Bd -literal -offset indent
# dconschat -rTC 5555 &
# telnet localhost 5555
.Ed
.Pp
You may want to keep logging console output of several machines.
.Nm conserver-com
in the Ports collection may help you.
Insert the following lines in
.Pa conserver.cf :
.Bd -literal -offset indent
console local {
	master localhost;
	type exec;
	exec /usr/sbin/dconschat -rh 25;
}
console remote {
	master localhost;
	type exec;
	exec /usr/sbin/dconschat -rh 25 -t 00-11-22-33-44-55-66-77;
}
.Ed
.Sh SEE ALSO
.Xr gdb 1 ,
.Xr telnet 1 ,
.Xr kvm 3 ,
.Xr dcons 4 ,
.Xr dcons_crom 4 ,
.Xr ddb 4 ,
.Xr firewire 4 ,
.Xr fwohci 4 ,
.Xr gdb 4 ,
.Xr eui64 5 ,
.Xr fwcontrol 8
.Sh AUTHORS
.An Hidetoshi Shimokawa Aq simokawa@FreeBSD.org
.Sh BUGS
This utility is
.Ud