157 lines
4.9 KiB
Forth
157 lines
4.9 KiB
Forth
\ Copyright (c) 2006-2011 Devin Teske <dteske@FreeBSD.org>
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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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\
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\ THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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\ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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\ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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\ ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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\ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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\ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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\ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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\ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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\ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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\ OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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\ SUCH DAMAGE.
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\
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\ $FreeBSD$
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marker task-check-password.4th
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include /boot/screen.4th
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13 constant enter_key \ The decimal ASCII value for Enter key
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8 constant bs_key \ The decimal ASCII value for Backspace key
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16 constant readmax \ Maximum number of characters for the password
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variable readX \ Current X offset (column)(used by read)
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variable read-start \ Starting X offset (column)(used by read)
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create readval 16 allot \ input obtained (maximum 16 characters)
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variable readlen \ input length
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\ This function blocks program flow (loops forever) until a key is pressed.
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\ The key that was pressed is added to the top of the stack in the form of its
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\ decimal ASCII representation. Note: the stack cannot be empty when this
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\ function starts or an underflow exception will occur. Simplest way to prevent
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\ this is to pass 0 as a stack parameter (ie. `0 sgetkey'). This function is
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\ called by the read function. You need not call it directly. NOTE: arrow keys
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\ show as 0 on the stack
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\
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: sgetkey ( -- )
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begin \ Loop forever
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key? if \ Was a key pressed? (see loader(8))
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drop \ Remove stack-cruft
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key \ Get the key that was pressed
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\ Check key pressed (see loader(8)) and input limit
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dup 0<> if ( and ) readlen @ readmax < if
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\ Echo an asterisk (unless Backspace/Enter)
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dup bs_key <> if ( and ) dup enter_key <> if
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." *" \ Echo an asterisk
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then then
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exit \ Exit from the function
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then then
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\ Always allow Backspace and Enter
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dup bs_key = if exit then
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dup enter_key = if exit then
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then
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50 ms \ Sleep for 50 milliseconds (see loader(8))
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again
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;
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: read ( -- String prompt )
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0 25 at-xy \ Move the cursor to the bottom-left
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dup 1+ read-start ! \ Store X offset after the prompt
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read-start @ readX ! \ copy value to the current X offset
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0 readlen ! \ Initialize the read length
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type \ Print the prompt
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begin \ Loop forever
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0 sgetkey \ Block here, waiting for a key to be pressed
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\ We are not going to echo the password to the screen (for
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\ security reasons). If Enter is pressed, we process the
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\ password, otherwise augment the key to a string.
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\ If the key that was entered was not Enter, advance
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dup enter_key <> if
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readX @ 1+ readX ! \ Advance the column
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readlen @ 1+ readlen ! \ Increment input length
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then
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\ Handle backspacing
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dup bs_key = if
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readX @ 2 - readX ! \ Set new cursor position
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readlen @ 2 - readlen ! \ Decrement input length
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\ Don't move behind starting position
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readX @ read-start @ < if
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read-start @ readX !
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then
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readlen @ 0< if
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0 readlen !
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then
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\ Reposition cursor and erase character
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readX @ 25 at-xy 1 spaces readX @ 25 at-xy
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then
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dup enter_key = if
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drop \ Clean up stack cruft
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10 emit \ Echo new line
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exit
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then
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\ If not Backspace or Enter, store the character
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dup bs_key <> if ( and ) dup enter_key <> if
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\ store the character in our buffer
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dup readval readlen @ 1- + c!
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then then
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drop \ drop the last key that was entered
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again \ Enter was not pressed; repeat
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;
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: check-password ( -- )
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\ Exit if a password was not set
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s" password" getenv dup -1 = if
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drop exit
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then
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begin \ Loop as long as it takes to get the right password
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s" Password: " \ Output a prompt for a password
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read \ Read the user's input until Enter
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2dup readval readlen @ compare 0= if
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2drop exit \ Correct password
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then
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\ Bad Password
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3000 ms
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." loader: incorrect password" 10 emit
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again \ Not the right password; repeat
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;
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