1.\" Copyright (c) 2003 Hidetoshi Shimokawa 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 16.\" DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 17.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 18.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 19.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 21.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 22.\" ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 23.\" POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.\" 28.Dd September 29, 2022 29.Dt DCONSCHAT 8 30.Os 31.Sh NAME 32.Nm dconschat 33.Nd user interface to 34.Xr dcons 4 35.Sh SYNOPSIS 36.Nm 37.Op Fl brvwRT1 38.Op Fl e Ar escape-char 39.Op Fl h Ar hz 40.Op Fl C Ar console_port 41.Op Fl G Ar gdb_port 42.Op Fl M Ar core 43.Op Fl N Ar system 44.Nm 45.Op Fl brvwR1 46.Op Fl h Ar hz 47.Op Fl C Ar console_port 48.Op Fl G Ar gdb_port 49.Op Fl a Ar address 50.Op Fl u Ar bus_num 51.Fl t Ar target_eui64 52.Sh DESCRIPTION 53The 54.Nm 55utility is designed to provide a way for users to access 56.Xr dcons 4 57(dumb console device) on a local or remote system. 58The 59.Nm 60utility interacts with 61.Xr dcons 4 62using 63.Xr kvm 3 64or 65.Xr firewire 4 , 66and interacts with the user over TTY or TCP/IP. 67To access remote 68.Xr dcons 4 69using 70.Xr firewire 4 , 71you have to specify target EUI64 address using the 72.Fl t 73option. Physical DMA should be enabled on the target machine for access 74via FireWire. 75.Pp 76The 77.Nm 78utility and the 79.Xr dcons 4 80driver communicate using 2 ports, one for the console port and another 81for remote 82.Xr gdb 1 Pq Pa ports/devel/gdb 83port. 84Users are supposed to access 85.Nm 86using TTY, 87.Xr telnet 1 88and 89.Xr gdb 1 Pq Pa ports/devel/gdb . 90You can specify listen ports for console and 91.Xr gdb 1 Pq Pa ports/devel/gdb 92port using the 93.Fl C 94and 95.Fl G 96options respectively. 97The port number 0 has special meaning that 98current TTY (stdin/stdout) is used instead of TCP/IP. 99A negative port number will disable the port. 100By analogy with 101.Xr pty 4 102device, the 103.Xr dcons 4 104acts as a slave device and 105.Nm 106acts as a master device with 107.Nm telnetd . 108.Pp 109Typed characters are normally transmitted directly to 110.Xr dcons 4 . 111A escape character (the default is 112.Ql ~ 113) appearing as the first character of a line is an escape signal; the 114following are recognized: 115.Bl -tag -width ident 116.It Ic ~. 117Drop the connection and exit. 118.It Ic ~^G 119Invoke kgdb on the terminal on which dconschat is running. 120.It Ic ~^R 121Reset the target over FireWire if a reset address is registered in Configuration ROM. 122.It Ic ~^Z 123Suspend the dconschat process. 124.El 125.Pp 126The following options are supported. 127.Bl -tag -width indent 128.It Fl b 129Translate Ctrl-C to ALT_BREAK (CR + 130.Ql ~ 131+ Ctrl-B) on 132.Xr gdb 1 Pq Pa ports/devel/gdb 133port. 134.It Fl r 135Replay old buffer on connection. 136.It Fl v 137Verbose debug output. 138Multiple 139.Fl v 140options increase verbosity. 141.It Fl w 142Listen on a wildcard address rather than localhost. 143.It Fl R 144Read-only. 145Do not write anything to the 146.Xr dcons 4 147buffer. 148.It Fl T 149Enable ad-hoc workaround for the TELNET protocol to 150remove unnecessary byte sequences. 151It should be set when you access 152.Nm 153using 154.Xr telnet 1 . 155.It Fl 1 156One-shot. 157Read available buffer, then exit. 158This implies the 159.Fl r 160option. 161.It Fl e Ar escape-char 162Specify escape character. 163The default is '~'. 164.It Fl h Ar hz 165Specify polling rate. 166The default value is 100. 167.It Fl C Ar console_port 168Specify the console port. 169The default value is 0 (stdin/stdout). 170.It Fl G Ar gdb_port 171Specify 172.Xr gdb 1 Pq Pa ports/devel/gdb 173port. 174The default value is \-1 (disabled). 175.It Fl M Ar core 176Specify core file. 177.It Fl N Ar system 178Specify system file such as 179.Pa /boot/kernel/kernel . 180.It Fl t Ar target_eui64 181Specify the 64-bit extended unique identifier of the target, 182and use FireWire to access remote 183.Xr dcons 4 . 184.It Fl a Ar address 185Specify the physical I/O address of the 186.Xr dcons 4 187buffer. 188See 189.Xr dcons 4 190for details. 191If this option is not specified, 192.Nm 193tries to get the address from the Configuration ROM on the target. 194You are supposed to enable 195.Xr dcons_crom 4 196on the target to omit this option. 197.It Fl u Ar bus_num 198Specify FireWire bus number. 199The default is 0. 200.El 201.Sh FILES 202.Bl -tag -width indent -compact 203.It Pa /dev/fwmem0.0 204.It Pa /dev/mem 205.It Pa /dev/kmem 206.El 207.Sh EXAMPLES 208To use 209.Nm 210with FireWire for remote 211.Xr dcons 4 , 212you have to specify the EUI64 of the target. 213You can obtain EUI64 by running 214.Xr fwcontrol 8 215without options. 216The first EUI64 is of the host running 217.Xr fwcontrol 8 218and others on the bus follow. 219.Bd -literal -offset indent 220# fwcontrol 2212 devices (info_len=2) 222node EUI64 status 223 1 77-66-55-44-33-22-11-00 0 224 0 00-11-22-33-44-55-66-77 1 225.Ed 226.Pp 227The EUI64 does not change unless you change the hardware 228as the ethernet address. 229.Pp 230Now we can run 231.Nm . 232.Bd -literal -offset indent 233# dconschat -br -G 12345 -t 00-11-22-33-44-55-66-77 234.Ed 235.Pp 236You will get console output of the target and login prompt if a 237.Xr getty 8 238is running on 239.Xr dcons 4 . 240You can break to DDB with ALT_BREAK (CR + 241.Ql ~ 242+ Ctrl-B) 243if 244.Dv DDB 245and 246.Dv ALT_BREAK_TO_DEBUGGER 247are enabled in the target kernel. 248To quit the session, type CR + 249.Ql ~ 250+ 251.Ql \&. 252in the console port. 253.Pp 254Using 255.Xr gdb 1 Pq Pa ports/devel/gdb 256port is almost the same as remote 257.Xr gdb 1 Pq Pa ports/devel/gdb 258over serial line except 259using TCP/IP instead of 260.Pa /dev/cu* . 261See 262.Sx "On-line Kernel Debugging Using Remote GDB" 263section of 264.%T "The FreeBSD Developers Handbook" 265and 266.Xr gdb 4 267for details. 268.Bd -literal -offset indent 269% gdb -k kernel.debug 270(kgdb) target remote :12345 271.Ed 272.Pp 273Once 274.Xr gdb 1 Pq Pa ports/devel/gdb 275is attached and you specified the 276.Fl b 277option to 278.Nm , 279typing Ctrl-C in 280.Xr gdb 1 Pq Pa ports/devel/gdb 281causes a break to debugger. 282.Pp 283The following command gets the console log from the crash dump: 284.Bd -literal -offset indent 285# dconschat -1 -M vmcore.0 -N kernel.0 286.Ed 287.Pp 288If you want access to the console using 289.Xr telnet 1 , 290try the following: 291.Bd -literal -offset indent 292# dconschat -rTC 5555 & 293# telnet localhost 5555 294.Ed 295.Pp 296You may want to keep logging console output of several machines. 297.Nm conserver-com 298in the Ports collection may help you. 299Insert the following lines in 300.Pa conserver.cf : 301.Bd -literal -offset indent 302console local { 303 master localhost; 304 type exec; 305 exec /usr/sbin/dconschat -rh 25; 306} 307console remote { 308 master localhost; 309 type exec; 310 exec /usr/sbin/dconschat -rh 25 -t 00-11-22-33-44-55-66-77; 311} 312.Ed 313.Sh SEE ALSO 314.Xr gdb 1 Pq Pa ports/devel/gdb , 315.Xr telnet 1 , 316.Xr kvm 3 , 317.Xr dcons 4 , 318.Xr dcons_crom 4 , 319.Xr ddb 4 , 320.Xr firewire 4 , 321.Xr fwohci 4 , 322.Xr gdb 4 , 323.Xr eui64 5 , 324.Xr fwcontrol 8 325.Sh AUTHORS 326.An Hidetoshi Shimokawa Aq Mt simokawa@FreeBSD.org 327.Sh BUGS 328This utility is 329.Ud 330