202 lines
5.9 KiB
Groff
202 lines
5.9 KiB
Groff
.\" $NetBSD: cnmagic.9,v 1.13 2004/10/06 05:57:33 dbj Exp $
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.\"
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.\" Copyright (c) 2000 Eduardo Horvath
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed for the
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.\" NetBSD Project. See http://www.NetBSD.org/ for
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.\" information about NetBSD.
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" --(license Id: LICENSE.proto,v 1.1 2000/06/13 21:40:26 cgd Exp )--
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.\"
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.Dd November 11, 2000
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.Dt CNMAGIC 9
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.Os
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.Sh NAME
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.Nm cn_trap ,
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.Nm cn_isconsole ,
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.Nm cn_check_magic ,
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.Nm cn_init_magic ,
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.Nm cn_set_magic ,
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.Nm cn_get_magic ,
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.Nm cn_destroy_magic
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.Nd console magic key sequence management
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.Sh SYNOPSIS
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.In sys/systm.h
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.Va typedef struct cnm_state cnm_state_t;
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.Ft void
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.Fn cn_trap
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.Ft int
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.Fn cn_isconsole "dev_t dev"
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.Ft void
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.Fn cn_check_magic "dev_t dev" "int k" "cnm_state_t *cnms"
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.Ft void
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.Fn cn_init_magic "cnm_state_t *cnms"
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.Ft int
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.Fn cn_set_magic "char *magic"
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.Ft int
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.Fn cn_get_magic "char *magic" "int len"
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.Ft void
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.Fn cn_destroy_magic "cnm_state_t *cnms"
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.Sh DESCRIPTION
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The
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.Nx
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console magic key sequence management framework is designed to provide
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flexible methods to set, change, and detect magic key sequences on console
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devices and break into the debugger or ROM monitor with a minimum of interrupt
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latency.
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.Pp
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Drivers that generate console input should make use of these routines.
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A different
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.Va cnm_state_t
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should be used for each separate input stream.
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Multiple devices that share the same input stream, such as USB
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keyboards can share the same
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.Va cnm_state_t .
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Once a
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.Va cnm_state_t
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is allocated, it should be initialized with
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.Fn cn_init_magic
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so it can be used by
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.Fn cn_check_magic .
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If a driver thinks it might be the console input device it can set the
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magic sequence with
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.Fn cn_set_magic
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to any arbitrary string.
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Whenever the driver receives input, it should call
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.Fn cn_check_magic
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to process the data and determine whether the magic sequence has
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been hit.
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.Pp
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The magic key sequence can be accessed through the
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.Va hw.cnmagic
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.Ic sysctl
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variable.
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This is the raw data and may be keycodes rather than
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processed characters, depending on the console device.
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.Pp
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Here is a description of the console magic interface:
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.Bl -tag -width indent
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.It Fn "void cn_init_magic" "cnm_state_t *cnm"
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.Pp
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Initialize the console magic state pointed to by
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.Fa cnm
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to a usable state.
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.It Fn "void cnm_trap"
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.Pp
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Trap into the kernel debugger or ROM monitor.
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By default this routine is defined to be
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.Fn console_debugger
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but can be overridden in MI header files.
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.It Fn "int cn_isconsole" "dev_t dev"
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.Pp
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Determine whether a given
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.Fa dev
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is the system console.
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This macro tests to see if
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.Fa dev
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is the same as
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.Va cn_tab-\*[Gt]cn_dev
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but can be overridden in MI header files.
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.It Fn "void cn_check_magic" "dev_t dev" "int k" "cnm_state_t *cnms"
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.Pp
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All input should be passed through
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.Fn cn_check_magic
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so the state machine remains in a consistent state.
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.Fn cn_check_magic
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calls
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.Fn cn_isconsole
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with
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.Fa dev
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to determine if this is the console.
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If that returns true then it runs the input value
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.Fa k
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through the state machine.
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If the state machine completes a match of the current console magic sequence
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.Fn cn_trap
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is called.
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Some input may need to be translated to state machine
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values such as the serial line
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.Li BREAK
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sequence.
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.It Fn "void cn_destroy_magic" "cnm_state_t *cnms"
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.Pp
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This should be called once what
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.Fa cnms
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points to is no longer needed.
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.It Fn "int cn_set_magic" "char *magic"
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.Fn cn_set_magic
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encodes a
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.Li nul
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terminated string arbitrary string into values that can be used by
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the state machine and installs it as the global magic sequence.
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The escape sequence is character value
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.Li 0x27
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and can be used to encode special values:
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.Pp
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.Bl -tag -width "0x001" -compact -offset indent
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.It 0x27
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The literal value
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.Li 0x27 .
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.It 0x01
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Serial
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.Li BREAK
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sequence.
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.It 0x02
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.Li Nul
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character.
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.El
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Returns
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.Li 0
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on success or a non-zero error value.
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.It Fn "int cn_get_magic" "char *magic" "int len"
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Extract the current magic sequence from the state machine and return
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up to
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.Fa len
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bytes of it in the buffer pointed to by
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.Fa magic .
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It uses the same encoding accepted by
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.Fn cn_set_magic .
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Returns
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.Li 0
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on success or a non-zero error value.
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.El
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.Sh SEE ALSO
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nx
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console magic key sequence management framework
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first appeared in
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.Nx 1.6 .
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.Sh AUTHORS
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The
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.Nx
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console magic key sequence management framework was designed and
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implemented by
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.An Eduardo Horvath
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.Aq eeh@NetBSD.org .
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