.TH RDBFS 4
.SH NAME
rdbfs \- remote kernel debugging file system
.SH SYNOPSIS
.B rdbfs
[
.B -d
]
[
.B -p 
.I pid
]
[
.B -s
.I srvname
]
[
.B -t
.I text
]
[
.I device
]
.SH DESCRIPTION
.I Rdbfs
presents in 
.BI /proc/ pid
(default
.BR /proc/1 )
a set of process files for debugging
a kernel over the serial line 
.I device
(default 
.BR /dev/eia0 ).
If the
.B -s
option is given,
.I rdbfs
will post its channel in
.BI /srv/ srvname
(see
.IR srv (3)),
allowing the session to be shared or reattached later.
.PP
The 
.B text
file presented is just a copy of
.I text
(default
.BR /386/9pc ).
It can usually be ignored, since
the debuggers open kernel
files directly rather than
using
.BI /proc/ n /text\fR.
.PP
Kernels can be remotely debugged  only when they are
suspended and serving
a textual debugging protocol over their serial lines.
Typing 
.RB `` ^t^td ''
.RB (control- t ", control-" t ", d)"
at the console will cause the kernel to enter
this mode when it `panics'.
Typing 
.RB `` ^t^tD '' 
causes the kernel to enter this mode immediately.
.PP
Because the debugging protocol is textual, a console
provided by
.IR consolefs (4)
may be substituted for the serial device.
.SH SOURCE
.B /sys/src/cmd/rdbfs.c
.br
.B /sys/src/9/port/rdb.c
.SH "SEE ALSO"
.IR acid (1),
.IR db (1),
.IR consolefs (4)