;**************************************************************************
;
; CANTDO.M68 - "Can't Do" Shell program
;
; Written by: Dave Heyliger - AMUS Staff
;
; Purpose: To scan all keyboard input and make sure the
; command entered is "aok" to perform. If a match
; is found in the "can't do" list, then the user
; "can't do" this command.
;
; Usage: Entering in CANTDO from the dot will allow this JOB
; to only do the commands that are NOT found in the
; CANTDO list at the end of this source file. You may
; "FORCE JOB CANTDO" from within AMOSL.INI as the last
; command in the list of FORCEing if you want the user
; to come up under the CANTDO shell upon boot.
;
; IMPORTANT: if you have a user in the CANTDO shell, be sure
; the user "exits out" of the CANTDO shell before
; LOGOFF. You should create some simple command
; file called "BYE" or whatever, place this command
; file in the CMD: account, and have all users of
; CANTDO use this command file to log off the system.
; All this command file does is execute the two character
; "escape sequence" before executing the LOGOFF program.
;
; Example: :S
; ~+
; :R
; LOGOFF
;
; It will also be up to you to figure out how you would
; like CANTDO to "come back up" on the JOB that has just
; performed the BYE command.
;
;**************************************************************************
DEFINE CLRCTC ;clear out a ^C when user hits one (fool them)
PUSH A6 ;"black box"
PUSH D7
JOBIDX A6 ;A6 now contains pointer to JOBIDX (JOBSTS)
MOVW #J.CCC,D7 ;Reg. D7 contains ^C abort flag
COMW D7 ;logical one's complement (0->1 and 1->0)
ANDW D7,@A6 ;flag is now turned OFF
POP D7 ;restore originalS
POP A6
ENDM
DEFINE CTC ;"set ctrlc"
PUSH A6 ;"black box"
JOBIDX A6 ;point to JOBIDX (JOBSTS)
LEA A6,JOBTYP(A6) ;A6 points to JOBTYP word
ORW #J.CCA,@A6 ;^C set
POP A6 ;restore original
ENDM
;START OF PROGRAM HERE!
;set control C
CTC ;set control C (just in case)
;perform the following loop over and over:
LOOP: PRTTAB -1,12. ;bright output
TYPE <.> ;simulate the AMOS dot
KBD ;get the input
CTRLC HITCC ;go here if user executes a ^C
TRM ;just a CR hit?
BEQ LOOP ;yup, type another dot
;user entered something other than just a CR. Setup pointers for scan
LEA A4,CANTDO ;point A4 to commands not allowed
LEA A5,LSTEND ;point A5 to end of the list
PUSH A2 ;save the command line
;look for a match in the CANTDO list
LOOK: CMP A4,A5 ;end of the list?
JEQ DOIT ;yup, they can do it
10$: CMPB (A2)+,(A4)+ ;look for letter match
BNE NMATCH ;if not equal, no match
CMPB @A4,#0 ;at end of a cantdo command?
BNE 10$ ;nope, not yet
;matched a command in CANTDO, but at end of origianl command line?
CMPB @A2,#'/ ;no slashes allowed
BEQ 20$ ;so go here if there is one
CMPB @A2,#40 ;no spaces either
BEQ 20$ ;go here if so
CMPB @A2,#'[ ;same goes for brackets
BEQ 20$ ;go here if so
CMPB @A2,#15 ;at a CR on the original command line?
BNE NMATCH ;nope, no match!
20$: POP A2 ;match! Adjust stack
LEA A2,NONO ;point to no-no message
TTYL @A2 ;type it out
JMP LOOP ;and start ALL over.
;didn't find a match yet
NMATCH: MOV @SP,A2 ;point A2 back to original command
JMP LOOK ;and relook some more
;looked through the entire list, no match found, so do command.
;HOWEVER, see if user knows secret code to get out. If they entered
;the secret code, get them out of CANTDO. (original version is "~+"
;
;NOTE: to change the secret code (a two character sequence), simply
; change the "~" and the "+" to any two funny characters you
; want. If you then re-assemble this program, these two chars
; will get you out of CANTDO.
;
DOIT: POP A2 ;point to original command
CMPB @A2,#'~ ;first exit character?
BNE 10$ ;nope
CMPB 1(A2),#'+ ;second exit character?
JEQ EXIT ;if equal, get em out
10$: AMOS ;else execute the command entered
JMP LOOP ;and start all over
;come here on a ^C
HITCC: CLRCTC ;clear control C
TYPECR <^C> ;simulate a ^C
JMP LOOP ;and start again
;Error message can be anything you like. Original has "?What?"
NONO: ASCII /?What?/ ;error message
BYTE 15,12,0 ;CRLF null
EVEN ;even out the next lable below
;Here is where you define all of the commands that users "can't do".
;For each command you want in the CANTDO list, enter in
;
; ASCIZ /command/
;
;Make sure that the last item in the list is EVEN (right before the
;LSTEND: label. Every time you add a new command to the CANTDO list,
;you must re-assemble the program.
;
;Note: if you define a command such as DIR to be a can't do command,
; then this program will not allow DIR, DIR/ etc. DIRSEQ will
; be allowed, however. I hope you get my drift.
;
CANTDO: ASCIZ /DIR/
ASCIZ /TYPE/
ASCIZ /SYSTAT/
ASCIZ /SYSTEM/
EVEN
LSTEND: WORD 0
