169 lines
4.6 KiB
Groff
169 lines
4.6 KiB
Groff
.\" $NetBSD: cons.9,v 1.12 2003/04/01 16:59:45 wiz Exp $
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.\"
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.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
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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 by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 1, 2003
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.Dt CONS 9
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.Os
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.Sh NAME
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.Nm cnbell ,
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.Nm cnflush ,
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.Nm cngetc ,
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.Nm cngetsn ,
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.Nm cnhalt ,
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.Nm cnpollc ,
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.Nm cnputc
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.Nd console access interface
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.Sh SYNOPSIS
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.Fd #include \*[Lt]dev/cons.h\*[Gt]
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.Ft void
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.Fn cnbell "u_int pitch" "u_int period" "u_int volume"
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.Ft void
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.Fn cnflush "void"
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.Ft int
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.Fn cngetc "void"
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.Ft int
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.Fn cngetsn "char *cp" "int size"
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.Ft void
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.Fn cnhalt "void"
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.Ft void
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.Fn cnpollc "int on"
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.Ft void
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.Fn cnputc "int c"
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.Sh DESCRIPTION
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These functions operate over current console device.
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The console must be initialized before these functions can be used.
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.Pp
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Console input polling functions
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.Fn cngetc ,
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.Fn cngetsn
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and
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.Fn cnpollc
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are only to be used during initial system
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boot, e.g., when asking for root and dump device or to get
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necessary user input within mountroothooks.
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Once the system boots, user input is read via standard
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.Xr tty 4
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facilities.
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.Pp
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The following is a brief description of each function:
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.Bl -tag -width "cngetsn()"
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.It Fn cnbell
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Ring a bell at appropriate
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.Fa pitch ,
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for duration of
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.Fa period
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milliseconds at given
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.Fa volume .
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Note that the
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.Fa volume
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value is ignored commonly.
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.It Fn cnflush
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Waits for all pending output to finish.
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.It Fn cngetc
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Poll (busy wait) for a input and return the input key.
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Returns 0 if there is no console input device.
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.Fn cnpollc
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.Em must
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be called before
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.Fn cngetc
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could be used.
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.Fn cngetc
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should be used during kernel startup only.
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.It Fn cngetsn
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Read one line of user input, stop reading once the newline
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key is input.
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Input is echoed back.
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This uses
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.Fn cnpollc
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and
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.Fn cngetc .
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Number of read characters is
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.Fa size
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at maximum, user is notified by console bell when the end
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of input buffer is reached.
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\*[Lt]Backspace\*[Gt] key works as expected.
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\*[Lt]@\*[Gt] or \*[Lt]CTRL\*[Gt]-u make
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.Fn cngetsn
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discard input read so far, print newline and
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wait for next input.
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.Fn cngetsn
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returns number of characters actually read, excluding
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the final newline.
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.Fa cp
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is
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.Em not
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zero-ended before return.
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.Fn cngetsn
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should be used during kernel startup only.
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.It Fn cnhalt
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Terminates the console device (i.e. cleanly shuts down the console hardware.)
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.It Fn cnpollc
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Switch the console driver to polling mode if
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.Fa on
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is nonzero, or back to interrupt driven mode if
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.Fa on
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is zero.
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.Fn cnpollc
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should be used during kernel startup only.
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.It Fn cnputc
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Console kernel output character routine.
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Commonly, kernel code uses
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.Xr printf 9
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rather than using this low-level interface.
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.El
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.Sh EXAMPLES
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This waits until a \*[Lt]Enter\*[Gt] key is pressed:
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.Pp
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.Bd -literal -compact
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int c;
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cnpollc(1);
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for(;;) {
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c = cngetc();
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if ((c == '\\r' || (c == '\\n')) {
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printf("\\n");
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break;
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}
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}
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cnpollc(0);
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.Ed
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.Sh SEE ALSO
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.Xr pckbd 4 ,
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.Xr pcppi 4 ,
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.Xr tty 4 ,
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.Xr wscons 4 ,
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.Xr wskbd 4 ,
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.Xr printf 9 ,
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.Xr spl 9 ,
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.Xr wscons 9
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