page ,132 if 0 /*++ Copyright (c) 1991 Microsoft Corporation Module Name: nw16.asm Abstract: This module contains the stub redir TSR code for NT VDM net support Author: Richard L Firth (rfirth) 05-Sep-1991 Colin Watson (colinw) 30-Jun-1993 Environment: Dos mode only Revision History: 05-Sep-1991 rfirth Created 30-Jun-1993 colinw ported to NetWare --*/ endif ; ; DOS include files ; .xlist .xcref include isvbop.inc ; NTVDM BOP mechanism include dossym.inc ; includes MS-DOS version etc include pdb.inc ; PSP defines include syscall.inc ; AssignOper include segorder.inc ; load order of 'redir' segments include debugmac.inc ; debug display macros include asmmacro.inc ; jumps which may be short or near include messages.inc include nwdos.inc ; NetWare structures and nwapi32 interface .cref .list ; ; Define externals in resident code and data ; ResidentCodeStart extrn Old21Handler:dword extrn NwInt21:near extrn hVDD:dword extrn quick_jump_to_dos:byte extrn for_dos_proper:byte extrn chain_previous_int21:byte extrn ConnectionIdTable:byte extrn not_exclusive:byte ResidentCodeEnd InitStack segment stack para 'stack' dw 256 dup (?) InitStack ends InitDataStart bad_ver_msg db NLS_MSG_001,c_CR,c_LF BAD_VER_MSG_LEN equ $-bad_ver_msg db '$' ; for INT 21/09 display string already_loaded_msg db NLS_MSG_004,c_CR,c_LF ALREADY_LOADED_MSG_LEN equ $-already_loaded_msg cannot_load_msg db NLS_MSG_005,c_CR, c_LF CANNOT_LOAD_MSG_LEN equ $-cannot_load_msg InitDataEnd InitCodeStart assume cs:InitCode assume ds:nothing assume es:nothing assume ss:nothing public DllName DllName db "NWAPI16.DLL",0 public InitFunc InitFunc db "Nw16Register",0 public DispFunc DispFunc db "Nw16Handler",0 public start start proc near ; ; when we start up we could be on any old PC - even an original, so don't ; assume anything other than a model-T processor ; .8086 ; ; Set the data segment while we're at it - all paths set it sooner ; or later. NOTE: es will point to the PSP until we change it! ; mov dx,InitData mov ds,dx assume ds:InitData ; ; first off, get the DOS version. If we're not running on NT (VDM) then this ; TSR's not going to do much, so exit. Exit using various methods, depending ; on the DOS version (don't you hate compatibility?) ; mov ah,30h int 21h jc ancient_version ; version not even supported ; ; version is 2.0 or higher. Check it out. al = major#, ah = minor# ; cmp al,major_version jne invalid_version ; ; what do you know? We're actually running on NT (unless some evil programmer ; has pinched int 21h/30h and broken it!). Enable minimum instruction set ; for NTVDM (286 on RISC). ; .286c ; ; perform an installation check by calling one of our entry points ; (GetFileServerNameTable). If this returns a table pointer in ES:DI then we ; know this TSR is already active, in which case we bail out now ; push es push di xor di,di mov es,di mov ax,0ef03h int 21h mov ax,es or ax,di pop di pop es jnz already_here ; ; OK, the NetWare redir is not already loaded - we're in business. ; Find entrypoints to nwapi16.dll Get and set the various interrupt ; vectors, Calculate the amount of space we want to keep, ; free up any unused space (like the environment segment), display a message ; in the DEBUG version, then terminate and stay resident. Remember: at this ; point we expect ES to point at the PSP ; call PullInDll jc already_here ; failed to load call InstallInterruptHandlers assume es:nothing push es pop ds call is_c_on_command_line jz @f mov dx,ResidentCode mov ds,dx assume ds:ResidentCode mov not_exclusive, 1 assume ds:nothing @@: ; ; free the environment segment ; mov es,es:[PDB_environ] mov ah,49h int 21h ; free environment segment ;if DEBUG ;ifdef VERBOSE ; DbgPrintString <"NetWare Redir successfully loaded",13,10> ;endif ;endif ; ; finally terminate and stay resident ; mov dx,ResidentEnd sub dx,ResidentStart ; number of paragraphs in resident code add dx,10h ; additional for PSP (PDB) ;if DEBUG ;ifdef VERBOSE ; DbgPrintString "Staying resident with " ; DbgPrintHexWord dx ; DbgPrintString " paragraphs. Load seg is ",NOBANNER ; mov ah,62h ; int 21h ; DbgPrintHexWord bx ; DbgPrintString " current seg is ",NOBANNER ; DbgPrintHexWord cs ; DbgCrLf ;endif ;endif mov ax,3100h int 21h ; terminate and stay resident ; ; here if the MS-DOS version check (Ah=30h) call is not supported ; ancient_version: mov dx,InitData mov ds,dx assume ds:InitData mov dx,offset bad_ver_msg mov ah,9 ; cp/m-style write to output int 21h ; ; safe exit: what we really want to do here is INT 20H, but when you do this, ; CS must be the segment of the PSP of this program. Knowing that CD 20 is ; embedded at the start of the PSP, the most foolproof way of doing this is ; to jump (using far return) to the start of the PSP ; push es xor ax,ax push ax retf ; terminate ; ; we are running on a version of DOS >= 2.00, but its not NT, so we still can't ; help. Display the familiar message and exit, but using a less programmer- ; hostile mechanism ; invalid_version: mov dx,offset bad_ver_msg mov cx,BAD_VER_MSG_LEN jmps print_error_message_and_exit ; ; if we cannot initialize 32-bit support (because we can't find/load the DLL) ; then put back the hooked interrupt vectors as they were when this TSR started, ; display a message and fail to load the redir TSR ; initialization_error: call RestoreInterruptHandlers mov dx,offset cannot_load_msg mov cx,CANNOT_LOAD_MSG_LEN jmps print_error_message_and_exit ; ; The DOS version's OK, but this TSR is already loaded ; already_here: mov dx,offset already_loaded_msg mov cx,ALREADY_LOADED_MSG_LEN print_error_message_and_exit: mov bx,1 ; bx = stdout handle mov ah,40h ; write to handle int 21h ; write (cx) bytes @ (ds:dx) to stdout mov ax,4c01h ; terminate program int 21h ; au revoir, cruel environment start endp ;******************************************************************************* ;* ;* InstallInterruptHandlers ;* ;* Sets the interrupt handlers for all the ints we use - 21 ;* ;* ENTRY es = PSP segment ;* ds = ;* ;* EXIT Old21Handler contains the original interrupt 21 vector ;* ;* RETURNS nothing ;* ;* ASSUMES ;* ;******************************************************************************* InstallInterruptHandlers proc push es ; PSP segment - destroyed by INT 21/35h push ds ; ; note: if we use ResidentCode here, explicitly, instead of seg OldMultHandler, ; then we can leave out an extraneous load of ds for the ISR address ; mov dx,ResidentCode mov ds,dx assume ds:ResidentCode ; ; Add ourselves to the int 21 chain ; mov ax,3521h int 21h mov word ptr Old21Handler,bx mov word ptr Old21Handler+2,es mov word ptr quick_jump_to_dos+1,bx mov word ptr quick_jump_to_dos+3,es mov word ptr for_dos_proper+1,bx mov word ptr for_dos_proper+3,es mov word ptr chain_previous_int21+1,bx mov word ptr chain_previous_int21+3,es mov dx,offset ResidentCode:NwInt21 mov ax,2521h int 21h pop ds ; restore segment registers pop es ret InstallInterruptHandlers endp ;******************************************************************************* ;* ;* RestoreInterruptHandlers ;* ;* Resets the interrupt handlers for all the ints we use - 21 ;* ;* ENTRY Old21Handler ;* contain the interrupt vectors from before nw16.sys was loaded ;* ;* EXIT Original interrupt vectors are restored ;* ;* RETURNS nothing ;* ;* ASSUMES ;* ;******************************************************************************* RestoreInterruptHandlers proc push ds assume ds:nothing push es mov dx,ResidentCode mov es,dx assume es:ResidentCode lds dx,Old21Handler mov ax,2521h int 21h pop es pop ds ret RestoreInterruptHandlers endp ;******************************************************************************* ;* ;* PullInDll ;* ;* Does a RegisterModule to load NWAPI32.DLL into our NTVDM.EXE ;* ;* ENTRY nothing ;* ;* EXIT nothing ;* ;* RETURNS cf if fails. ;* ;* ASSUMES Earth moves round Sun ;* ;******************************************************************************/ PullInDll proc near pusha ; dispatch code push dx ; save callers dx,ds,es,ax push ds push es push ax mov dx,InitCode mov ds,dx assume ds:InitCode push ds pop es assume es:InitCode mov si,offset DllName ; ds:si = nwapi32.dll mov di,offset InitFunc ; es:di = init routine mov bx,offset DispFunc ; ds:bx = dispatch routine mov ax,ResidentCode mov dx,offset ConnectionIdTable ; ax:dx = shared datastructure RegisterModule jc @f mov dx,ResidentCode mov ds,dx assume ds:ResidentCode mov word ptr hVDD,ax @@: pop ax ; callers ax pop es ; callers es pop ds ; callers ds pop dx ; callers dx assume ds:nothing assume es:nothing popa ; dispatch code ret PullInDll endp ;******************************************************************************* ;* ;* is_c_on_command_line ;* ;* -C or /C means we should open compatiblity mode createfiles as shared ;* instead of exclusive ;* ;* ENTRY ds points to PDB ;* ;* EXIT nothing ;* ;* RETURNS zero if not found. ;* ;* ASSUMES ds points at PSP ;* ;******************************************************************************/ is_c_on_command_line proc near mov si,80h lodsb cbw mov cx,ax next: jcxz quit dec cx lodsb check_next: cmp al,'-' je check_c cmp al,'/' je check_c cmp al,' ' je next cmp al,9 je next find_ws:jcxz quit dec cx lodsb cmp al,' ' je next cmp al,9 je next jmp short find_ws check_c:jcxz quit dec cx lodsb or al,20h cmp al,'c' jne find_ws or cx,ax quit: or cx,cx ret is_c_on_command_line endp InitCodeEnd end start