The Business Master (3rd Edition)

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Assembly Source File | 1992-07-05 | 24.5 KB | 648 lines

;WATCH.ASM - Modified for ShowMCBs 5.00 by Tom Gilbert's Heart & Mind ;resident routine watches programs going resident and keeps a list of ;interrupt vector changes in an internal table of data structures ;====================================================================== ; to be assembled by TASM ; Copyright (c) 1986,1991 Kim Kokkonen, TurboPower Software. ; May be freely distributed but not sold except by permission. ; telephone: 719-260-6641, Compuserve 76004,2611 ;====================================================================== ; version 2.2 3/4/87 ; First release, version to be consistent with MAPMEM.PAS ; : ; long intervening history ; : ; version 3.0 9/24/91 ; add tracking for TSRs that unload themselves ; add support for TSRs loaded high ; WATCH may be loaded high ; version 3.1 11/4/91 ; rewrite again to solve problems with SWAPMM, FSP, DATAPATH, DATAMON ; version 3.2 11/22/91 ; change method of accessing high memory ; deal with DOS 5 MODE int trapping (int seg < psp seg) ; version 3.3 1/8/92 ; relocate AddChain code so that it doesn't get overwritten if there ; are lots of initial memory blocks ; version 3.4 2/14/92 ; no change ; version 3.5 7/5/92 ; cosmetic changes like these line lengths and ; terminating "TSR WATCHER" command line with CR ; nulled out storage area and put "SS"s in Stack ; this makes RamView(ing) less confusing and the ; initialization messages are different on 1 line. ;====================================================================== ;uncomment following line to generate more publics in MAP file ; debug = 1 cseg segment public para assume cs:cseg, ds:nothing, es:nothing, ss:nothing locals @@ org 080H cmdline label byte ;pointer to command line org 100H pentry: jmp init ;always put the following in WATCH.MAP to update MEMU.PAS public nextchange,emesg,changevectors,origvectors ;********************************************************************** ;data structures part of COM file even nextchange dw 0 ;next position to write ;in changes area firstmcb dw ? ;first MCB segment firsthimcb dw 0 ;first high memory MCB segment ;temporary stack used by interrupt handler newsp dw ? ;initial stack pointer newss dw ? ;segment of our temporary stack tmpret dw ? ;used while switching stacks ;information saved about the calling program oldsp dw ? ;stack pointer oldss dw ? ;stack segment ;previous interrupt handlers dos_int label dword old21 dw 2 dup (?) ;old int21 vector tsr_int label dword old27 dw 2 dup (?) ;old int27 vector ;XMS access xmsadr label dword ;XMS control address xmsxxx dw 2 dup (0) ;id code for a PSP data block pspid equ 0FFFFH ;id used to start a PSP block ;structure of a changevectors data block pspblock struc id dw ? ;id word, always pspid psp dw ? ;psp segment len dw ? ;length of psp unu1 dw ? ;unused pspblock ends vecblock struc vec dw ? ;vector number 0..255 veco dw ? ;vector offset vecs dw ? ;vector segment unu2 dw ? ;unused vecblock ends ;********************************************************************** ;resident data structures not part of COM file changevectors = offset emesg ;data area overwrites emesg vrecsize = 8 ;bytes/vector change record maxchanges = 128 ;maximum vector changes vsize = maxchanges*vrecsize ;size of vector change area ;vector table buffers origvectors = offset changevectors+vsize ;original vector table veclen = 1024 ;size of vector table newstackpos = origvectors+veclen ;location of newstack ssize = 128 ;bytes in temporary stack newloc = newstackpos+ssize ;stack top and end of TSR ;********************************************************************** ;int21 handler ; traps functions 31, 49, 4C, and 7761 int21h proc far ifdef debug public int21h endif assume ds:nothing pushf ;save flags sti ;allow interrupts cmp ah,31H ;TSR call? jne @@1 call addcurrpsp ;dx = paras to keep jmp short @@4 @@1: cmp ah,49H ;deallocate block call? jne @@2 call remblock ;remove specified block jmp short @@4 ;if a psp @@2: cmp ah,4CH ;normal program halt? jne @@3 call checkblocks jmp short @@4 @@3: cmp ax,7761H ;"wa"tch ID call? jne @@4 call checkblocks ;assure change list up to date push bp mov bp,sp ;set up stack frame and word ptr [bp+8],0FFFEH ;clear carry flag pop bp xchg ah,al ;flip ah and al as a signature mov bx,cs ;return WATCH psp in bx popf iret ;return to caller @@4: popf jmp dos_int ;let DOS take over int21h endp ;********************************************************************** ;int27 handler ; watches for programs going resident int27h proc far ifdef debug public int27h endif assume ds:nothing pushf sti push dx add dx,15 ;pass size of block in paras shr dx,1 shr dx,1 shr dx,1 shr dx,1 call addcurrpsp ;get current psp and add block to list pop dx popf jmp tsr_int int27h endp ;********************************************************************** ;get current PSP in bx and add new block ;entry: dx = paragraphs to keep addcurrpsp proc near ifdef debug public addcurrpsp endif assume ds:nothing call setup ;switch stacks and save registers assume ds:cseg mov ah,51H ;get current PSP in bx pushf call dos_int call addblock ;add block at bx, length dx to changes call shutdown ;restore registers and switch stacks assume ds:nothing ret addcurrpsp endp ;*********************************************************************** ;remove PSP block, if any, specified by es remblock proc near ifdef debug public remblock endif assume ds:nothing call setup ;switch stacks and save registers assume ds:cseg mov bx,es ;save segment being deallocated in bx call matchpsp ;return offset from changevectors or si,si ;any matching block? jz @@1 call rempsp ;remove psp @@1: call shutdown ;restore registers and switch stacks assume ds:nothing ret remblock endp ;********************************************************************** ;scan chain of mcbs starting at segment ax ;remove halting psp from change list if needed checkchain proc near ifdef debug public checkchain endif @@1: mov es,ax mov bx,es:[0001h] ;bx = psp of block mov dx,es:[0003h] ;dx = len of block inc ax cmp ax,bx ;does psp = mcb+1? jne @@2 ;jump if not cmp ax,cx ;does psp = current program? je @@2 ;jump if so push dx call matchpsp ;find changevectors psp match pop dx or si,si ;is there a matching psp? jnz @@2 ;jump if so push ax push cx push dx call addblock ;add this psp pop dx pop cx pop ax @@2: cmp byte ptr es:[0000h],'Z' ;end of chain je @@3 add ax,dx jmp @@1 @@3: ret checkchain endp ;********************************************************************** ;check for new memory blocks and add if needed ;remove halting psp from change list if needed checkblocks proc near ifdef debug public checkblocks endif assume ds:nothing call setup ;switch stacks & save registers assume ds:cseg mov ah,51H ;get current psp in bx pushf call dos_int call matchpsp ;is current program or si,si ;in change list? jz @@0 ;jump if not call rempsp ;remove it if not @@0: mov cx,bx ;cx = psp of halting program mov ax,firstmcb ;start with first mcb call checkchain ;check this chain mov ax,firsthimcb ;scan high memory or ax,ax jz @@1 call checkchain @@1: call shutdown ;restore regs & switch stacks assume ds:nothing ret checkblocks endp ;********************************************************************** ;setup routine for interrupt hook routines ; switches stacks, saves registers, sets ds=cs setup proc near ifdef debug public setup endif assume ds:nothing pop cs:tmpret ;save return address as switch stacks mov oldss,ss ;save current stack mov oldsp,sp cli ;switch to our stack mov ss,newss mov sp,newsp sti push ax ;store registers push bx push cx push dx push si push di push bp push ds push es push cs ;set ds=cs pop ds assume ds:cseg push cs:tmpret ;return ret setup endp ;********************************************************************** ;shutdown routine for interrupt hook routines ; restores registers, switches stacks shutdown proc near ifdef debug public shutdown endif pop cs:tmpret pop es ;restore registers pop ds assume ds:nothing pop bp pop di pop si pop dx pop cx pop bx pop ax cli ;restore stack mov ss,cs:oldss mov sp,cs:oldsp sti push cs:tmpret ;return ret shutdown endp ;********************************************************************** ;add specified block to changes ; entry: bx = psp of block, dx = length of block in paras addblock proc near ifdef debug public addblock endif assume ds:cseg call addhdr ;add a psp header block call addvecs ;add blocks for each hooked vector ret addblock endp ;********************************************************************** ;add header for a psp block ; entry: bx = psp of block, dx = length of block in paras ; exit: alters di addhdr proc near ifdef debug public addhdr endif assume ds:nothing mov di,nextchange cmp di,vsize-vrecsize ;assure room for next record ja @@1 mov word ptr cs:changevectors[di].id,pspid mov cs:changevectors[di].psp,bx mov cs:changevectors[di].len,dx add di,vrecsize mov nextchange,di @@1: ret addhdr endp ;********************************************************************** ;add vector blocks for each hooked vector ; entry: bx = psp of block, dx = length of block in paras ; exit: alters ax,cx,dx,si,di,bp addvecs proc near ifdef debug public addvecs endif assume ds:cseg push ds add dx,bx ;now dx points to end of block mov di,nextchange ;cs:changevectors[di] -> blocks xor si,si mov ds,si ;ds:si -> vectors assume ds:nothing xor cx,cx ;cx = vector counter cld ;forward @@1: lodsw ;ax = vector offset mov bp,ax ;save vector offset lodsw ;ax = vector segment cmp ax,dx ;is vector above high limit? jae @@3 push cx mov cx,ax cmp bp,800h ;don't add unless offset small ja @@1a ;(this is trap for DOS 5 MODE) push bp shr bp,1 shr bp,1 shr bp,1 shr bp,1 add cx,bp ;ax = equivalent segment of int pop bp @@1a: cmp cx,bx ;is vector above low limit? jb @@2 pop cx cmp di,vsize-vrecsize ;room for another entry? ja @@3 mov cs:changevectors[di].vec,cx ;save entry for this vector mov cs:changevectors[di].veco,bp mov cs:changevectors[di].vecs,ax add di,vrecsize jmp short @@3 @@2: pop cx @@3: inc cx ;next vector cmp cx,0FFh jbe @@1 mov nextchange,di pop ds assume ds:cseg ret addvecs endp ;********************************************************************** ;find changeblock matching psp ; entry: bx = psp to match ; exit: si = matching block, or 0 if none ; destroys dx matchpsp proc near ifdef debug public matchpsp endif assume ds:cseg mov si,offset changevectors mov dx,si add dx,nextchange ;dx = next unused changevector @@1: cmp si,dx ;end of table jae @@3 cmp word ptr [si].id,pspid ;psp indicator? jnz @@2 ;jump if not cmp [si].psp,bx ;matching psp? jnz @@2 ;jump if not ret ;else return with match @@2: add si,vrecsize jmp @@1 @@3: xor si,si ;no match if here ret matchpsp endp ;********************************************************************** ;remove all blocks associated with psp at offset si ; exit: alters cx,dx,si,di,es rempsp proc near ifdef debug public rempsp endif assume ds:cseg mov di,si ;save destination add si,vrecsize ;move to next record mov dx,offset changevectors add dx,nextchange ;dx = address of next unused @@1: cmp si,dx ;end of table? jae @@2 ;jump if so cmp word ptr [si].id,pspid ;next psp indicator? je @@2 ;jump if so add si,vrecsize ;next block jmp @@1 ;and loop @@2: mov cx,dx sub cx,si shr cx,1 ;cx = words to move push cs pop es ;es = ds = cs cld rep movsw ;copy down remaining blocks sub si,di sub nextchange,si ;update nextchange ret rempsp endp align 16 ;********************************************************************** ;resident portion above, temporary portion below ;********************************************************************** emesg db 'already ' imesg db 'installed.',13,10,36 mesg db 'WATCH 3.5, ' pname db 'TSR WATCHER' plen equ $-pname ;length of command line db ', Copyright 1992 TurboPower Software, $' ;********************************************************************** init proc near ifdef debug public init endif assume ds:cseg mov dx,offset mesg ;success message mov ah,09H int 21H ;DOS print string ;use int 21h test to check for previous installation mov ax,7761H ;special id function int 21H ;if function fails jc @@1 ;not installed cmp ax,6177H ;if id code not returned jnz @@1 ;not installed ;error exit mov dx,offset emesg ;error message mov ah,09H int 21H ;DOS print string mov ax,4C01H ;exit with error int 21H ;not already installed @@1: mov dx,offset imesg ;success message mov ah,09H int 21H ;DOS print string ;initialize location of WATCH stack mov newsp,newstackpos+ssize mov newss,cs ;stack seg is code seg ;put id label at offset 80H to allow other programs to recognize WATCH mov cx,plen ;length of name string mov si,offset pname ;offset of name string mov di,offset cmdline ;offset of DOS command line cld ;transfer in forward direction mov al,cl stosb ;store length byte first rep movsb ;transfer characters mov byte ptr es:[di],13 ;terminate command line ;relocate ourselves out of the way of the resident tables push cs pop es mov di,newloc+10H push di ;will act as a return address mov si,offset @@2 mov cx,endcode-@@2 rep movsb ;move code ret ;"return" to the relocated code @@2: ;store image of original vector table (overwrites messages & used code) push cs pop es xor ax,ax ;nul-out mov di,offset emesg ;storage mov cx,400h ;area rep stosw ;words mov ax,"SS" ;Initialize mov cx,64 ;Stack Words rep stosw mov di,origvectors push ds xor si,si ;offset 0 mov ds,si ;source address segment 0 mov cx,200H ;512 words to store rep movsw ;copy vectors to our table pop ds ;add psp records for all blocks already resident call adddummypsp ;store current int 21 and 27 vectors mov ax,3527H int 21H mov old27,bx mov old27[2],es mov ax,3521H int 21H mov old21,bx mov old21[2],es ;install new vectors mov ax,2527H mov dx,offset int27h int 21H mov ax,2521H mov dx,offset int21h int 21H ;terminate and stay resident mov dx,newloc add dx,15 mov cl,4 shr dx,cl mov ax,3100H ;return success code int 21H ;note WATCH will track itself @@3: init endp ;********************************************************************** ;add dummy changeblocks for psps resident in chain starting at ax addchain proc near ifdef debug public addchain endif assume ds:cseg @@1: mov es,ax mov bx,es:[0001h] ;bx = psp of block mov dx,es:[0003h] ;dx = len of block inc ax cmp ax,bx ;does psp = mcb+1? jne @@2 ;jump if not cmp ax,newss ;does psp = WATCH itself? je @@2 ;jump if so mov cx,offset addhdr call cx ; call addhdr ;add a header for this block @@2: cmp byte ptr es:[0000h],'Z' ;end of chain je @@3 add ax,dx jmp @@1 @@3: ret addchain endp ;********************************************************************** ;return segment of first high memory mcb in ax findhimemstart proc near ifdef debug public findhimemstart endif mov ax,3000h ;get DOS version int 21H cmp al,3 jb @@7 ;no XMS driver possible mov ax,4300h int 2Fh ;multiplex call for XMS cmp al,80h ;proper signature? jne @@7 ;no XMS driver mov ax,4310h int 2Fh mov xmsxxx,bx ;save XMS control address mov xmsxxx[2],es mov ah,10h mov dx,0FFFFh call xmsadr ;ask to allocate FFFF UMB paras cmp bl,0B0h ;if fail but UMBs available je @@0 ;then get top of memory cmp bl,0B1h ;if UMBs all allocated jne @@7 ;then no UMBs available @@0: int 12H mov cl,6 shl ax,cl ;get segment of top of memory @@1: mov es,ax cmp byte ptr es:[0000h],'M' ;potential mcb? jnz @@6 ;not an mcb, try next segment @@2: mov cx,ax ;save potential start mcb in cx @@3: inc ax add ax,es:[0003h] ;ax = start of next mcb jc @@5 ;can't be an mcb if we wrapped mov es,ax ;address of next mcb mov dl,es:[0000h] cmp dl,'M' jz @@3 ;good start mcb cmp dl,'Z' jz @@9 ;good end mcb @@5: mov ax,cx ;restore last start segment @@6: cmp ax,0FFFFh ;top of memory? je @@7 inc ax ;try next segment jmp @@1 @@7: xor cx,cx ;no matching UMB @@9: mov ax,cx ;return segment in ax ret findhimemstart endp ;********************************************************************** ;add dummy changeblocks for all psps already resident adddummypsp proc near ifdef debug public adddummypsp endif assume ds:cseg mov ah,52H int 21H ;get DOS list of lists mov ax,es:[bx-2] ;get first MCB segment mov firstmcb,ax ;save it for use later too call addchain call findhimemstart ;find first high memory mcb mov firsthimcb,ax ;save it for use later too or ax,ax jz @@1 call addchain ;add blocks in high memory too @@1: ret adddummypsp endp endcode: cseg ends end pentry