dconschat man page on FreeBSD

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DCONSCHAT(8)		  BSD System Manager's Manual		  DCONSCHAT(8)

NAME
     dconschat — user interface to dcons(4)

SYNOPSIS
     dconschat [-brvwRT1] [-e escape-char] [-h hz] [-C console_port]
	       [-G gdb_port] [-M core] [-N system]
     dconschat [-brvwR1] [-h hz] [-C console_port] [-G gdb_port] [-a address]
	       [-u bus_num] -t target_eui64

DESCRIPTION
     The dconschat utility is designed to provide a way for users to access
     dcons(4) (dumb console device) on a local or remote system.  The
     dconschat utility interacts with dcons(4) using kvm(3) or firewire(4),
     and interacts with the user over TTY or TCP/IP.  To access remote
     dcons(4) using firewire(4), you have to specify target EUI64 address
     using the -t option. Physical DMA should be enabled on the target machine
     for access via FireWire.

     The dconschat utility and the dcons(4) driver communicate using 2 ports,
     one for the console port and another for remote gdb(1) port.  Users are
     supposed to access dconschat using TTY, telnet(1) and gdb(1).  You can
     specify listen ports for console and gdb(1) port using the -C and -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 pty(4) device, the dcons(4) acts
     as a slave device and dconschat acts as a master device with telnetd(8).

     Typed characters are normally transmitted directly to dcons(4).  A escape
     character (the default is ‘~’ ) appearing as the first character of a
     line is an escape signal; the following are recognized:

     ~.	    Drop the connection and exit.

     ~^G    Invoke kgdb on the terminal on which dconschat is running.

     ~^R    Reset the target over FireWire if a reset address is registered in
	    Configuration ROM.

     ~^Z    Suspend the dconschat process.

     The following options are supported.

     -b	     Translate Ctrl-C to ALT_BREAK (CR + ‘~’ + Ctrl-B) on gdb(1) port.

     -r	     Replay old buffer on connection.

     -v	     Verbose debug output.  Multiple -v options increase verbosity.

     -w	     Listen on a wildcard address rather than localhost.

     -R	     Read-only.	 Do not write anything to the dcons(4) buffer.

     -T	     Enable ad-hoc workaround for the TELNET protocol to remove unnec‐
	     essary byte sequences.  It should be set when you access
	     dconschat using telnet(1).

     -1	     One-shot.	Read available buffer, then exit.  This implies the -r
	     option.

     -e escape-char
	     Specify escape character.	The default is '~'.

     -h hz   Specify polling rate.  The default value is 100.

     -C console_port
	     Specify the console port.	The default value is 0 (stdin/stdout).

     -G gdb_port
	     Specify gdb(1) port.  The default value is -1 (disabled).

     -M core
	     Specify core file.

     -N system
	     Specify system file such as /boot/kernel/kernel.

     -t target_eui64
	     Specify the 64-bit extended unique identifier of the target, and
	     use FireWire to access remote dcons(4).

     -a address
	     Specify the physical I/O address of the dcons(4) buffer.  See
	     dcons(4) for details.  If this option is not specified, dconschat
	     tries to get the address from the Configuration ROM on the tar‐
	     get.  You are supposed to enable dcons_crom(4) on the target to
	     omit this option.

     -u bus_num
	     Specify FireWire bus number.  The default is 0.

FILES
     /dev/fwmem0.0
     /dev/mem
     /dev/kmem

EXAMPLES
     To use dconschat with FireWire for remote dcons(4), you have to specify
     the EUI64 of the target.  You can obtain EUI64 by running fwcontrol(8)
     without options.  The first EUI64 is of the host running fwcontrol(8) and
     others on the bus follow.

	   # 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

     The EUI64 does not change unless you change the hardware as the ethernet
     address.

     Now we can run dconschat.

	   # dconschat -br -G 12345 -t 00-11-22-33-44-55-66-77

     You will get console output of the target and login prompt if a getty(8)
     is running on dcons(4).  You can break to DDB with ALT_BREAK (CR + ‘~’ +
     Ctrl-B) if DDB and ALT_BREAK_TO_DEBUGGER are enabled in the target ker‐
     nel.  To quit the session, type CR + ‘~’ + ‘.’ in the console port.

     Using gdb(1) port is almost the same as remote gdb(1) over serial line
     except using TCP/IP instead of /dev/cu*.  See On-line Kernel Debugging
     Using Remote GDB section of The FreeBSD Developers Handbook and gdb(4)
     for details.

	   % gdb -k kernel.debug
	   (kgdb) target remote :12345

     Once gdb(1) is attached and you specified the -b option to dconschat,
     typing Ctrl-C in gdb(1) causes a break to debugger.

     The following command gets the console log from the crash dump:

	   # dconschat -1 -M vmcore.0 -N kernel.0

     If you want access to the console using telnet(1), try the following:

	   # dconschat -rTC 5555 &
	   # telnet localhost 5555

     You may want to keep logging console output of several machines.
     conserver-com in the Ports collection may help you.  Insert the following
     lines in conserver.cf:

	   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;
	   }

SEE ALSO
     gdb(1), telnet(1), kvm(3), dcons(4), dcons_crom(4), ddb(4), firewire(4),
     fwohci(4), gdb(4), eui64(5), fwcontrol(8)

AUTHORS
     Hidetoshi Shimokawa ⟨simokawa@FreeBSD.org⟩

BUGS
     This utility is currently under development.

BSD			       February 11, 2003			   BSD
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