;	Title	Share_1 -  IBM CONFIDENTIAL
;				   $SALUT (0,36,41,44)
				   %include "sharehdr.mac"
;
;     Label: "The DOS SHARE Utility"
;	     "Version 4.00 (C) Copyright 1988 Microsoft"
;	     "Licenced Material - Program Property of Microsoft"
;
;******************* END OF SPECIFICATIONS *************************************

section SHARE align=16 PUBLIC class=SHARE
extrn				   fnm:near, rsc:near, rmn:near, cps:near, ofl:near, sle:near, interr:near

;				   NAME Sharer

				   [list -]
;				   .xcref
				   %include "dossym.mac"
;=== Push trace listing source: dpl.nas
				   %include "dpl.nas" ; NASM included file
;=== Pop trace listing source
;				   .cref
				   [list +]

%ifndef IBM
 %iassign IBM 0
%endif
%ifndef Installed
 %iassign Installed 0
%endif

%iassign Installed	TRUE ; for installed version

; NASM original macros

%imacro OFF 2.nolist
 %if Installed
	mov %1, offset %2
 %else
	mov %1, offset %2 wrt DOSGROUP
 %endif
%endmacro

%unimacro detectstripangles 4.nolist

%imacro detectstripangles 4.nolist
%defstr %%param %4
%assign ?%2 0
%assign ?%3 0
%rep 16
 %substr %%opening %%param 1
 %ifidn %%opening, '<'
  %substr %%param %%param 2,-1
  %assign ?%2 ?%2 + 1
 %endif
%endrep
%rep 16
 %strlen %%length %%param
 %substr %%closing %%param %%length
 %ifidn %%closing, '>'
  %substr %%param %%param 1,-2
  %assign ?%3 ?%3 + 1
 %endif
%endrep
%deftok %%token %%param
%define ?%1 %%token
%endmacro

%unimacro errnz 1.nolist

%imacro errnz 1.nolist
detectstripangles %%token, %%opening, %%closing, %1
%if ? %+ %%token
    %error %1 <> 0, ERRNZ failed
%endif
%endmacro

; end of NASM original macros

mft equ MFT	; NASM port label
quux equ mft

; if we are installed, then define the base code segment of the sharer first

				   %IF	Installed
section SHARE
; (no prior section) ; Share				   ENDS
; include the rest of the segment definitions for normal msdos
; We CANNOT include dosseg because start is not declared para in that file

section WLEMITALIGNED align=16
;	$SALUT	(4,9,17,36)

section DOSSTART align=16 PUBLIC class=DOSSTART
; (no prior section) ; DOSSTART	ENDS

section START align=1 PUBLIC class=START
; (no prior section) ; START	ENDS

section CONSTANTS align=2 PUBLIC class=CONST
; (no prior section) ; CONSTANTS ENDS

section DATA align=2 PUBLIC class=DATA
; (no prior section) ; DATA	ENDS

section TABLE align=1 PUBLIC class=TABLE
; (no prior section) ; TABLE	ENDS

section CODE align=1 PUBLIC class=CODE
; (no prior section) ; CODE	ENDS

section LAST align=16 PUBLIC class=LAST
; (no prior section) ; LAST	ENDS

group DOSGROUP DOSSTART START CONSTANTS DATA TABLE CODE LAST
	%ELSE
	%include "dosseg.nas"
	%ENDIF

section STACK stack class=STACK
; (no prior section) ; STACK	ENDS

section DATA
	Extrn	ThisSFT:DWORD	   ; pointer to SFT entry
	Extrn	User_ID:WORD
	Extrn	Proc_ID:WORD
	Extrn	WFP_START:WORD
	Extrn	BytPos:DWORD
	extrn	OpenBuf:BYTE
	extrn	user_in_ax:WORD
	%IF	debug
	    Extrn   BugLev:WORD
	    Extrn   BugTyp:WORD
	    %include "bugtyp.nas"
	%ENDIF
; (no prior section) ; DATA	ENDS

;   if we are not installed, then the code here is just part of the normal
;   MSDOS code segment otherwise, define our own code segment

;	.sall
	%IFN INSTALLED
section CODE
	    ASSUME  SS:DOSGROUP,CS:DOSGROUP
	%ELSE
section SHARE
	    ASSUME  SS:DOSGROUP,CS:SHARE
	%ENDIF

	extrn	MFT:BYTE
	extrn	skip_check:BYTE

	%include "mft.mac"

FreLock equ Frelock	; NASM port label
	PUBLIC	FreLock,Serial

	%IF	installed
Frelock     DW	    ?		   ; FWA of lock free list
	%ELSE
Frelock     DW	    OFFSET lck8 wrt DOSGROUP ; FWA of lock free list
	%ENDIF
Serial	DW	0		   ; serial number
DS_Org	dw	0		   ;an000;DS on entry to routine

ZERO	EQU	0
ONE	EQU	1

FRAME	struc

SavedBP dw	?
RetOFF	dw	?
Parm_1	dw	?
Parm_2	dw	?

FRAME	ends

;  $SALUT (4,4,9,41)

   BREAK <Sharer - MultiProcess File Sharer>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MSDOS MFT Functions
;
;	The Master File Table (MFT) associates the cannonicalized pathnames,
;	lock records and SFTs for all files open on this machine.
;
;	These functions are supplied to maintain the MFT and extract
;	information from it.  All MFT access should be via these routines so
;	that the MFT structure can remain flexible.
;
;******************* END OF SPECIFICATIONS *************************************

   BREAK <Mft_enter - Make an MFT entry and check access>

;******************* START OF SPECIFICATIONS ***********************************
;
;	mft_enter - make an entry in the MFT
;
;	mft_enter is called to make an entry in the MFT.
;	mft_enter checks for a file sharing conflict:
;		No conflict:
;		    A new MFT entry is created, or the existing one updated,
;		    as appropriate.
;		Conflicts:
;		    The existing MFT is left alone.  Note that if we had to
;		    create a new MFT there cannot be, by definition, sharing
;		    conflicts.
;	If no conflict has been discovered, the SFT list for the file is
;	checked for one that matches the following conditions:
;
;	    If mode == 70 then
;		don't link in SFT
;		increment refcount
;	    If mode&sfIsFCB and userids match and process ids match then
;		don't link in SFT
;
;	ENTRY	ThisSFT points to an SFT structure.  The sf_mode field
;		    contains the desired sharing mode.
;		WFP_Start is an offset from DOSGroup of the full pathname for
;		    the file
;		User_ID = 16-bit user id of issuer
;		Proc_ID = 16-bit process id of issuer
;		(DS) = (SS) = DOSGroup
;	EXIT	'C' clear if no error'
;		'C' set if error
;		  (ax) = error code
;	USES	ALL but DS
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure mft_enter,NEAR

;  int 3
   nop
   nop

   EnterCrit critShare

   DOSAssume SS, <DS>, "MFT_Enter entry"
   ASSUME ES:NOTHING,SS:DOSGROUP
   push ds

;	find or make a name record

WFP_Start equ WFP_START	; NASM port label
   mov	si,[WFP_Start]			; (DS:SI) = FBA of file name
   mov	al,1				; allow creation of MFT entry
   push es

   ASSUME DS:NOTHING

FNM equ fnm	; NASM port label
   call FNM				; find or create name in MFT
   pop	es
   mov	ax,error_sharing_buffer_exceeded
   jc	ent9				; not enough space
;
;	(bx) = fwa name record
;
   lds	si,[ss:ThisSFT]
   call ASC				; try to add to chain

;	As noted above, we don't have to worry about an "empty" name record
;	being left if ASC refuses to add the SFT - ASC cannot refuse if we had
;	just created the MFT...

;	return.
;
;	'C' and (Ax) setup appropriately

ent9: pop ds

   LeaveCrit critShare

   ret

   EndProc mft_enter

   BREAK <MftClose - Close out an MFT for given SFT>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MFTclose
;
;	MFTclose(SFT)
;
;	MFTclose removes the SFT entry from the MFT structure.	If this was
;	the last SFT for the particular file the file's entry is also removed
;	from the MFT structure.  If the sharer is installed after some
;	processing has been done, the MFT field of the SFTs will be 0; we must
;	ignore these guys.
;
;	If the sft indicates FCB, we do nothing special.  The SFT behaves
;	    EXACTLY like a normal handle.
;
;	If the sft indicates mode 70 then we do nothing special.  These are
;	normal HANDLES.
;
;	Note that we always care about the SFT refcount.  A refcount of 1
;	means that the SFT is going idle and that we need to remove the sft
;	from the chain.
;
;	ENTRY	(ES:DI) points to an SFT structure
;		(DS) = (SS) = DOSGroup
;	EXIT	NONE
;	USES	ALL but DS, ES:DI
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure MFTclose,NEAR

;  int 3
   nop
   nop

   EnterCrit critShare

   DOSAssume SS,<DS>,"MFTClose entry"
   ASSUME ES:NOTHING
   mov	ax,[es:di + sf_MFT]

   fmt	TypShare,LevShEntry,<"MFTClose by $x:$x of $x:$x ($x)\n">,<User_ID,Proc_id,ES,DI,AX>

   or	ax,ax
   jz	mcl10				; No entry for it, ignore (carry clear)
   push ds
   push es
   push di
;;;call CSL				; clear SFT locks		       ;AC008;

   ASSUME DS:NOTHING

   mov	ax,[es:di + sf_ref_count] 	; (ax) = ref count
;
; We need to release information in one of two spots.  First, when the SFT has
; a ref count of 0.  Here, there are no more referents and, thus, no sharing
; record need be kept.	Second, the ref count may be -1 indicating that the
; sft is being kept but that the sharing information is no longer needed.
; This occurs in creates of existing files, where we verify the allowed
; access, truncate the file and regain the access.  If the truncation
; generates an error, we do NOT want to have the access locked down.
;


   OR	AX,AX
   jz	mcl85				; ref count is 0 - don't dechain
   inc	ax				; -1 + 1 = 0.  Busy sft.
   jnz	mcl9
mcl85:
   call CSL				; clear SFT locks		       ;AC008;
RSC equ rsc	; NASM port label
   call RSC				; remove sft from chain
   jnz	mcl9				; not the last sft for this name
RMN equ rmn	; NASM port label
   call RMN				; remove name record
mcl9:
   pop	di				; restore regs for exit
   pop	es
   pop	ds
mcl10:
   LeaveCrit critShare

   ret

   EndProc MFTclose

   BREAK <MftClU - Close out all MFTs for given UID>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MFTcloseU
;
;	MFTcloseM(UID)
;
;	MFTcloseM removes all entrys for user UID from the MFT structure.  We
;	    walk the MFT structure closing all relevant SFT's for the user.
;	    We do it the dumb way, iterating closes until the SF ref count is
;	    0.
;
;	ENTRY	User_ID = 16-bit user id of issuer
;		(SS) + DOSGroup
;	EXIT	'C' clear
;	USES	ALL
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure MFTclU,NEAR

;  int 3
   nop
   nop

   ASSUME DS:NOTHING,ES:NOTHING,SS:DOSGROUP

   EnterCrit critShare
   mov	ax,[ss:User_ID]

   fmt	TypShare,LevShEntry,<"\nCloseUser $x\n">,<AX>

   sub	bx,bx				; insensitive to PID
   sub	dx,dx
   invoke BCS				; bulk close the SFTs
   LeaveCrit critShare
   return
   EndProc MFTclU

   BREAK <MftCloseP - Close out all MFTs for given UID/PID>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MFTcloseP
;
;	MFTcloseP(PID, UID)
;
;	MFTcloseP removes all entrys for process PID on machine MID from the
;	    MFT structure.  We walk the MFT structure closing all relevant
;	    SFT's.  Do it the dumb way by iterating closes until the SFTs
;	    disappear.
;
;	ENTRY	(SS) = DOSGROUP
;		User_ID = 16-bit user id of issuer
;		Proc_ID = 16-bit process id of issuer
;	EXIT	'C' clear
;	USES	ALL
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure MFTcloseP,NEAR

;  int 3
   nop
   nop

   ASSUME DS:NOTHING,ES:NOTHING,SS:DOSGROUP

   EnterCrit critShare
   mov	ax,[ss:User_ID]
   mov	bx,-1
   mov	dx,[ss:Proc_ID]

   fmt	TypShare,LevShEntry,<"\nClose UID/PID $x:$x\n">,<AX,DX>

   call BCS				; Bulk close the SFTs
   LeaveCrit critShare

   ret

   EndProc MFTcloseP

   BREAK <MftCloN - Close file by name>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MFTcloseN
;
;	MFTcloseN(name)
;
;	MFTcloseN removes all entrys for the given file from the MFT
;	structure.
;
;	NOTE: this function is used infrequently and need not be fast.
;		(although for typical use it's not all that slow...)
;
;	ENTRY	DS:SI point to dpl.
;		(SS) = DOSGroup
;	EXIT	'C' clear if no error
;		'C' set if error
;		  AX = error_path_not_found if not currently open
;	USES	ALL
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure MFTcloN,NEAR

;  int 3
   nop
   nop

   ASSUME SS:DOSGROUP,ES:NOTHING,DS:NOTHING

   EnterCrit critShare
   MOV	DX,[SI + DPL_DX]
   MOV	DS,[SI + DPL_DS]
   mov	si,dx				; (DS:SI) = fwa name
   sub	al,al				; don't create if not found
   push ds
   push si
   call FNM				; find name in MFT
   mov	ax,error_path_not_found 	; assume error
   jc	mclo9				; not found exit

;	Name was found.  Lets yank the SFT entrys one at a time.

mclo1: les di,[bx + mft_sptr]		; (ES:DI) = SFT address
   mov	WORD PTR [ss:ThisSFT],di
   mov	WORD PTR [ss:ThisSFT+2],es		; point to SFT
   cmp	word [es:di + sf_ref_count],1
   jnz	mclo15
CPS equ cps	; NASM port label
   call CPS
mclo15:
   Context DS

   %IF	installed
multDOS equ MultDOS	; NASM port equate
       MOV  AX,(multDOS << 8) + 1
       INT  2FH
   %ELSE
       call DOS_Close
   %ENDIF
mclo2:

   ASSUME DS:NOTHING

   pop	si
   pop	ds
   push ds
   push si
   sub	al,al				; don't create an entry
   call FNM				; find the name gain
   jnc	mclo1				; got still more
   clc

;	exit.  'C' and (ax) setup
;
;	(TOS+2:TOS) = address of ASCIZ string

mclo9: pop si				; clean stack
   pop	ds
   LeaveCrit critShare

   ret

   EndProc MFTcloN

   BREAK <Set_Mult_Block - Try to set multiple locks>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Set_Mult_Block  -  Set Multiple Block Locks
;
;  FUNCTION:	   Set_Mult_Block sets a lock on 1 or more specified ranges
;		   of a file.  An error is returned if any lock range conflicts
;		   with another. Ranges of Locks are cleared via Clr_Mult_Block.
;
;		   In DOS 3.3 only one lock range could be set at a time using
;		   Set_Block.  For DOS 4.00 this routine will replace Set_Block
;		   in the jump table and will make repeated calls to Set_Block
;		   in order to process 1 or more lock ranges.
;
;		   NOTE: - This is an all new interface to IBMDOS
;
;  INPUT:	   (AL) = 0  - lock all
;			= 80 - lock write
;		   (CX) = the number of lock ranges
;		   (DS:DX) = pointer to the range list
;		   (ES:DI) = SFT address
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = DOSGroup
;
;  OUTPUT:	   Lock records filled in for all blocks specified
;
;  REGISTERS USED: ALL but DS
;  (NOT RESTORED)
;
;  LINKAGE:	   IBMDOS Jump Table
;
;  EXTERNAL	   Invoke: Load_Regs, Set_Block, Clr_Block
;  REFERENCES:
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:	     (ax) = error code
;			       ('error_lock_violation' if conflicting locks)
;
;  CHANGE	04/15/87 - First release
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Set_Mult_Block
;
;	count = start_count
;	search till count = 0
;		invoke Load_Regs
;		invoke Set_Block
;	exit if error
;		clear_count = start_count - current_count
;		loop till clear_count = 0
;			invoke Load_Regs
;			invoke Clr_Block
;		leave if error
;		end loop
;		set error status
;	orelse
;	endloop
;		set successful status
;	endsrch
;	if error status
;		load return code
;	endif
;	return
;
;	END Set_Mult_Block
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Set_Mult_Block,NEAR

;	PUSH	DS			;ICE
;	push	bx			;ICE
;	push	ax			;ICE

;	mov	bx,0140H		;ICE
;	xor	ax,ax			;ICE
;	mov	ds,ax			;ICE
;	mov	ax,word ptr [ds:bx]	;ICE
;	mov	word ptr [ds:bx],ax	;ICE

;	pop	ax			;ICE
;	pop	bx			;ICE
;	POP	DS			;ICE



   EnterCrit critShare			;				       ;AN000;

   ASSUME ES:NOTHING,DS:NOTHING 	;				       ;AN000;
;	      set up for loop

;      WE HAVE:   (from IBMDOS) 	|	  WE NEED:   (for Set_Block)

; (AL)	  = 0 - lock all		|    (BX)    = 0 lock all operations
;	  = 80- lock write		|	     = 1 lock write operations
; (CX)	  = the number of lock ranges	|    (CX:DX) = offset of area
; (DS:DX) = pointer to the range list	|    (SI:AX) = length of area
; (ES:DI) = SFT address 		|    (ES:DI) = SFT address

;  int 3
   nop
   nop

   mov	[cs:DS_Org],ds			;an000;save entry DS

   Context DS				;				       ;AN000;
   CMP	CX,01h				;DO WE HAVE A COUNT?		       ;AN000;

;; $if	ae				; if the count was valid	       ;AN000;
;  $if	e				; if the count was valid	       ;AC006;
   JNE D_$IF1

;;     PUSH CX				; count = start_count		       ;AN000;
;;     PUSH DX				; save pointer to range list	       ;AN000;
       MOV  BP,DX			; save current index into list	       ;AN000;
;;     AND  AX,0080H			; clear high byte and be sure low is   ;AN000;
					; set if applicable
;;     ROL  AL,1			; move high bit to bit 0
;;     MOV  BX,AX			; SET UP TYPE OF LOCK		       ;AN000;

;;     $do				; loop till count = 0		       ;AN000;
;;	   cmp	cx,00			;an000;see if at end
;;     $leave e 			;an000;exit if at end
;;	   push cx			;an000;save cx - our counter
;;	   push di			;an000;save di - our SFT pointer
load_regs equ Load_Regs	; NASM port label
       call load_regs			;an000;load the registers for call
					;      to set_block
set_block equ Set_Block	; NASM port label
       call set_block			;an000;set the lock block
;;	   pop	di			;an000;restore our SFT pointer
;;	   pop	cx			;an000;restore cx - our counter
;;     $leave c 			;an000;on error exit loop
;;	   dec	cx			;an000;decrease counter
;;     $enddo				;an000;end loop

;;     $if  c				;an000;if an error occurred
;;	   pop	dx			;an000;restore range list pointer
;;	   pop	ax			;an000;obtain original count
;;	   sub	ax,cx			;an000;determine how many locks set
;;	   mov	cx,ax			;an000;set the loop counter with count
;;	   mov	bp,dx			;an000;set bp to point to range list
;;	   $do				;an000;while cx not = 0
;;	       cmp  cx,00		;an000;at end?
;;	   $leave e			;an000;yes, exit
;;	       push cx			;an000;save cx - our counter
;;	       push di			;an000;save di - our SFT pointer
;;	       call load_regs		;an000;load the registers for call
					;      to clr_block
;;	       call clr_block		;an000;clear the locks
;;	       pop  di			;an000;restore our SFT pointer
;;	       pop  cx			;an000;restore cx - our counter
;;	   $leave c			;an000;on error exit
;;	       dec  cx			;an000;decrease counter
;;	   $enddo			;an000;
;;	   stc				;an000;signal an error occurred
;;     $else				;an000;no error occurred in locking
;;	   pop	ax			;an000;clear off the stack
;;	   pop	ax			;an000;   to balance it
;;	   clc				;an000;signal no error occurred
;;     $endif				;an000;
;  $else				;an000;cx was 0 - this is an error
   JMP SHORT D_$EN1
D_$IF1:
       stc				;an000;signal an error occurred
;  $endif				;				       ;an000;
D_$EN1:

;  $if	c				; if there was an error 	       ;AN000;
   JNC D_$IF4
       MOV  AX,error_lock_violation	; load the return code		       ;AN000;
;  $endif				; endif there was an error	       ;AN000;
D_$IF4:

   LeaveCrit critShare			;				       ;AN000;

   ret					; return - all set		       ;AN000;

   EndProc Set_Mult_Block

   BREAK <Load_Regs - Load Registers for ?_Block call>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Load_Regs - Load Registers for ?_Block calls
;
;  FUNCTION:	   This subroutine loads the High and Low Offsets and the
;		   High and Low lengths for Lock ranges from the Range List.
;
;  INPUT:	   (DS_Org:PB) - Range list entry to be loaded
;
;  OUTPUT:	   (DX) - Low Offset
;		   (CX) - High Offset
;		   (AX) - Low Length
;		   (SI) - High Length
;
;  REGISTERS USED: AX CX DX BP SI
;  (NOT RESTORED)
;
;  LINKAGE:	   Called by: Set_Mult_Block, Clr_Mult_Block
;
;  EXTERNAL	   none
;  REFERENCES:
;
;  NORMAL	   none
;  EXIT:
;
;  ERROR	   none
;  EXIT:
;
;  CHANGE	   04/15/87 - first release
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	  START Load_Regs
;
;	  recover index into range list
;	  advance pointer to next entry
;	  load DX - Low Offset
;	  load CX - High Offset
;	  load AX - Low Length
;	  load SI - High Length
;	  return
;
;	  END Load_Regs
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Load_Regs,NEAR

   push ds				; save our DS			       ;an000;
   mov	ds,[cs:DS_Org]			; get range list segment	       ;an000;
   mov	si,bp				; recover pointer		       ;AN000;
   ADD	BP,08h				; move to next entry in list	       ;AN000;
   MOV	DX,[SI] 			; low position			       ;AN000;
   MOV	CX,[SI+2]			; high position 		       ;AN000;
   MOV	AX,[SI+4]			; low length			       ;AN000;
   MOV	SI,[SI+6]			; high length			       ;AN000;
   pop	ds				; restore DS			       ;an000;

   ret					;				       ;AN000;

   EndProc Load_Regs

   BREAK <Clr_Mult_Block - Try to clear multiple locks>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Clr_Mult_Block  -  Clear Multiple Block Locks
;
;  FUNCTION:	   Clr_Mult_Block removes the locks on 1 or more specified
;		   ranges of a file.  An error is returned if any lock range
;		   does not exactly match. Ranges of Locks are set via
;		   Set_Mult_Block.
;
;		   In DOS 3.3 only one lock range could be cleared at a time
;		   using Clr_Block.  For DOS 4.00 this routine will replace
;		   Clr_Block in the jump table and will make repeated calls
;		   to Set_Block in order to process 1 or more lock ranges.
;
;		   NOTE: - This is an all new interface to IBMDOS
;			 - an unlock all 'lock all' request will unlock both
;			   'lock all' and 'lock write'.
;			 - an unlock all 'lock write' request will not unlock
;			   'lock all's. It will only unlock 'lock write's.
;			  (if you can understand the above statement,
;			  understanding the code will be easy!)
;
;  INPUT:	   (AL) = 0 - lock all
;			= 80- lock write
;		   (CX) = the number of lock ranges - NB: all if -1 ***
;		   (DS:DX) = pointer to the range list
;		   (ES:DI) = SFT address
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = DOSGroup
;
;  OUTPUT:	   Lock records filled in for all blocks specified
;
;  REGISTERS USED: ALL but DS
;  (NOT RESTORED)
;
;  LINKAGE:	   IBMDOS Jump Table
;
;  EXTERNAL	   Invoke: Load_Regs, Set_Block, Clr_Block, Clr_List
;  REFERENCES:
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:	     (ax) = error code
;			       ('error_lock_violation' if conflicting locks)
;
;  CHANGE	04/15/87 - First release
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Clr_Mult_Block
;
;	if count is valid and
;	if file (SFT) is 'shared' then
;		if count = all
;			find first RLR
;			loop till all RLR cleared
;				if PROC_ID matches and
;				if UID matches and
;				if SFT matches then
;					if ulocking lock_all or
;					if this RLR is lock_write
;						clear the lock
;					endif
;				endif
;				find next RLR
;			end loop
;		else
;			invoke Clr_List
;		endif
;		set successful status
;	else
;		set error status
;	endif
;	if error
;		load return code
;	endif
;
;	ret
;
;	END Clr_Mult_Block
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure clr_mult_block,NEAR


lock_all equ 0h

;	PUSH	DS			;ICE
;	push	bx			;ICE
;	push	ax			;ICE

;	mov	bx,0140H		;ICE
;	xor	ax,ax			;ICE
;	mov	ds,ax			;ICE
;	mov	ax,word ptr [ds:bx]	;ICE
;	mov	word ptr [ds:bx],ax	;ICE

;	pop	ax			;ICE
;	pop	bx			;ICE
;	POP	DS			;ICE

   EnterCrit critShare			;				       ;AN000;

   ASSUME ES:NOTHING,DS:NOTHING 	;				       ;AN000;

;  int 3
   nop
   nop

   mov	[cs:DS_Org],DS			;an000;save entry DS

   Context DS				;				       ;AN000;

   CMP	CX,01h				; do we have a count?		       ;AN000;
;; $IF	AE,AND				; IF A VALID COUNT
;  $IF	E,AND				; IF A VALID COUNT		       ;AC006;
   JNE D_$IF6
sf_mft equ sf_MFT	; NASM port equate
   cmp	word [es:di + sf_mft],0		; is this SFT shared?		       ;AN000;
;  $IF	NE				; AND IF FILE IS 'SHARED' THEN
   JE D_$IF6

;      WE HAVE:   (from IBMDOS) 	|	  WE NEED:

; (AL)	  = 0 - lock all		|    (AX)    = 0 lock all operations
;	  = 80- lock write		|	     = 1 lock write operations
; (CX)	  = - 1  (unlock all locks)	|    (DS)    = CS
;					|    (DS:DI) = previous RLR
;					|    (DS:SI) = current RLR
; (ES:DI) = current SFT 		|

;;     and  ax,0080h			;be sure it is set right (mask 80 bit) ;AC002;
					;    existing interface
;;     rol  al,1			;put high bit in bit 0		       ;AC002;

;;     CMP  CX,-1h			;				       ;AN000;
;;     $IF  E				; IF unlock all locks then	       ;AN000;

;;	   push cs			;				       ;AN000;
;;	   pop	ds			;				       ;AN000;
;;	   mov	cx,di			; ES:CX is the SFT		       ;AN004;

;	   ASSUME ds:nothing

;;	   mov	si,[es:di].sf_mft	; DS:SI points to MFT		       ;AN000;

;;	   lea	di,[si].mft_lptr	; DS:DI = addr of ptr to lock record   ;AN000;
;;	   mov	si,[di] 		; DS:SI = address of 1st lock record   ;AN000;

;;	   $DO				; loop through the RLR's               ;AN000;

;	DS:DI = points to previous RLR or MFT if no RLR.
;	DS:SI = points to current RLR
;	ES:CX = SFT address
;	AX    = lock type

;;	       and  si,si		; are we at the end of the chain?      ;AN000;
;;	   $LEAVE Z			; we'er done with CF = 0               ;AN000;

;;	       mov  bp,[si].rlr_pid	; get PROC_ID			       ;AN000;
;;	       cmp  bp,PROC_ID		; is it ours?			       ;AN000;
;;	       $IF  E,AND		;				       ;AN000;
;;	       mov  bp,es		;				       ;AN000;
;;	       cmp  bp,WORD PTR [si].rlr_sptr+2 ;			       ;AC004;
;;	       $IF  E,AND		;				       ;AN000;
;;	       cmp  cx,WORD PTR [si].rlr_sptr ; 			       ;AC004;
;;	       mov  si,[di]		; restore pointer to current (using    ;AN000;
					;			     previous)
;;	       $IF  E			; if it is ours 		       ;AN000;

;	this is it. its OURS !

;;		   cmp	ax,lock_all	;				       ;AN000;

;;		   $IF	E,OR		; if unlocking all or		       ;AN000;

;;		   mov	bp,[si].rlr_type ; get lock type		       ;AN000;
;;		   cmp	bp,rlr_lall	; is it lock all?		       ;AN000;

;;		   $IF	NE		; if not a LOCK ALL lock	       ;AN000;

;	remove the RLR from the chain

;;		       mov  bx,[si].rlr_next ; get the pointer to the next RLR ;AN000;
;;		       mov  [di],bx	; install it in the last	       ;AN000;

;	put defunct lock record on the free chain

;;		       mov  bx,Frelock	;				       ;AN000;
;;		       mov  [si].rlr_next,bx ;				       ;AN000;
;;		       mov  Frelock,si	;				       ;AN000;
;;		       mov  si,di	; back up to last		       ;AN000;

;;		   $ENDIF		; should we unlock it		       ;AN000;

;;	       $ENDIF			; it was ours!			       ;AN000;

;	advance to next RLR

;;	       mov  di,si		; load address of next RLR	       ;AN000;
;;	       mov  si,[di]		; update pointer to next RLR	       ;AN000;

;;	   $ENDDO			; loop back to the start	       ;AN000;

;;     $ELSE				; else, its a LIST !		       ;AN000;

;	      set up for loop

;      WE HAVE:   (from IBMDOS) 	|	  WE NEED:   (for Clr_Block)

; (AX)	  = 0 - lock all		|    (BX)    = 0 lock all operations
;	  = 1 - lock write		|	     = 1 lock write operations
; (CX)	  = the number of lock ranges	|    (CX:DX) = offset of area
; (DS:DX) = pointer to the range list	|    (SI:AX) = length of area
; (ES:DI) = SFT address 		|    (ES:DI) = SFT address

;;	   PUSH CX			; count = start_count		       ;AN000;
;;	   PUSH DX			; save pointer to range list	       ;AN000;
       MOV  BP,DX			; save current index into list	       ;AN000;
;;	   MOV	BX,AX			; SET UP TYPE OF LOCK		       ;AN000;

       call Clr_List			; call Clr_List to process the list    ;AN000;

;;     $ENDIF				;				       ;AN000;

;  $ELSE				; NOT VALID
   JMP SHORT D_$EN6
D_$IF6:

       STC				;				       ;AN000;

;  $ENDIF				; VALID/INVALID 		       ;AN000;
D_$EN6:

;  $IF	C				; if carry is set		       ;AN000;
   JNC D_$IF9
       MOV  AX,error_lock_violation	; load error condition		       ;AN000;
;  $ENDIF				; carry not set 		       ;AN000;
D_$IF9:

   LeaveCrit critShare			;				       ;AN000;

   ret					; return - all set		       ;AN000;

   EndProc clr_mult_block

   BREAK <Clr_List - Clear a list of user specified locks>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Clr_List  -	Clear a list of user specified locks
;
;  FUNCTION:	   Clr_List makes multiple calls to Clr_Block to clear
;		   multiple lock ranges of a file.  An error is returned
;		   if any lock range does not exactly match. Ranges of
;		   Locks are then set via Set_Mult_Block.
;
;
;  INPUT:	   (BX)    = 0 lock all operations
;			   = 1 lock write operations
;		   (CX:DX) = offset of area
;		   (SI:AX) = length of area
;		   (ES:DI) = SFT address
;		   (SS:SP+2)= original index \ see FRAME struc
;		   (SS:SP+4)= original count /
;
;  OUTPUT:	   Lock records removed for all blocks specified
;		   Stack cleard on return
;
;  REGISTERS USED: ALL but DS
;  (NOT RESTORED)
;
;  LINKAGE:	   IBMDOS Jump Table
;
;  EXTERNAL	   Invoke: Load_Regs, Set_Block, Clr_Block
;  REFERENCES:
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:	     (ax) = error code
;			       ('error_lock_violation' if conflicting locks)
;
;  CHANGE	04/15/87 - First release
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Clr_List
;
;	search till count = 0
;		set up for call
;		call clr_Block
;	exit if c
;		clear_count = start_count - current_count
;		loop till clear_count = 0
;			set up for call
;			call Set_Block
;		end loop
;		set error status
;	orelse
;	endloop
;		set successful status
;	endsrch
;	return
;
;	END Clr_List
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Clr_List,NEAR

;; $do					;an000;while cx not = 0
;;     cmp  cx,00			;an000;at end?
;; $leave e				;an000;yes
;;     push cx				;an000;save cx - our counter
;;     push di				;an000;save di - our SFT pointer
   call load_regs			;an000;set up for clr_block call
;;     push bp				; save pointer to range entry	       ;AN000;
clr_block equ Clr_Block	; NASM port label
   call clr_block			;an000;remove the lock
;;     pop  bp				; recover pointer to range entry       ;AN000;
;;     pop  di				;an000;restore our SFT pointer
;;     pop  cx				;an000;restore cx - our counter
;; $leave c				;an000;leave on error
;;     dec  cx				;an000;decrease counter
;; $enddo				;an000;

;; $if	c				;an000;an error occurred
;;     push bp				;an000;save bp
;;     mov  bp,sp			;an000;get sp
;;     mov  dx,[bp].parm_1		;an000;recover original index
;;     mov  ax,[bp].Parm_2		; original count		       ;AN000;
;;     pop  bp
;;     SUB  AX,CX			; how many did we do?		       ;AN000;
;;     MOV  CX,AX			; set up the loop		       ;AN000;
;;     MOV  BP,DX			; save the index		       ;AN000;

;;     $DO				;				       ;AN000;
;;	   cmp	cx,00			;an000;at end?
;;     $leave e 			;an000;yes
;;	   push cx			;an000;save cx - our counter
;;	   push di			;an000;save di - our SFT pointer
;;	   call load_regs		;an000;set up for set_block call
;;	   call set_block		;an000;reset the locks
;;	   pop	di			;an000;restore our SFT pointer
;;	   pop	cx			;an000;restore cx - our counter
;;     $leave c 			;an000;leave on error
;;	   dec	cx			;an000;decrease counter
;;     $enddo				;an000;
;;     stc				;an000;signal an error
;; $else				;an000;
;;     clc				;an000;signal no error
;; $endif				;an000;

;; ret	4				; return (clear Parm_1 & Parm_2)       ;AN000;
   ret					; return (clear Parm_1 & Parm_2)       ;AC006;

   EndProc Clr_List


   BREAK <Set_Block - Try to set a lock>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Set_Block - set byte range lock on a file
;
;  FUNCTION:	   Set_Block sets a lock on a specified range of a file.  An
;		   error is returned if the lock conflicts with another.
;		   Locks are cleared via clr_block.
;
;  INPUT:	   (ES:DI) = SFT address
;		   (CX:DX) = offset of area
;		   (SI:AX) = length of area
;		   (BX)    = 0 lock all operations
;			   = 1 lock write operations
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = DOSGroup
;
;  OUTPUT:	   Lock records removed for all blocks specified
;
;  REGISTERS USED: ALL but DS, BP
;  (NOT RESTORED)
;
;  LINKAGE:	   Invoked by: Set_Mult_Block
;
;  EXTERNAL	   Invoke: CLP (SLE), OFL
;  REFERENCES:
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:
;
;  CHANGE	04/15/87 - lock only write support
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Set_Block
;
;	if a valid SFT and
;	invoke CLP
;	if no lock conflicts and
;	invoke OFL
;	if empty lock record available
;		store SFT pointer
;		store lock range
;		add RLR to the chain
;		store PROC_ID
;		store rlr_type
;		set successful return status
;	else
;		set error return status
;	endif
;	return
;
;	END Set_Block
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Set_Block,NEAR

   ASSUME ES:NOTHING,DS:NOTHING

   Context DS

   push bp				; preserve (bp) 		       ;AN000;
   push ds				; preserve (ds)
;; push bx				; preserve (bx) 		       ;AN000;
   cmp	word [es:di + sf_mft],ZERO
;  $if	nz,and				; if file is SHARED and 	       ;AC000;
   JZ D_$IF11
   push di
clp equ CLP	; NASM port label
   call clp				; do common setup code

   ASSUME DS:NOTHING

   pop	bp
;  $if	nc,and				; if no (lock conflict) error and      ;AC000;
   JC D_$IF11

;	Its ok to set this lock.  Get a free block and fill it in
;	(es:bp) = sft
;	(ds:si) = pointer to name record
;	(ax:bx) = fba lock area
;	(cx:dx) = lba lock area
;	(ds:di) = pointer to pointer to previous lock
;	(TOS)	= saved (bx)
;	(TOS+1) = saved (ds)
;	(TOS+2) = saved (bp)

OFL equ ofl	; NASM port label
   call OFL				; (ds:di) = pointer to new, orphan lock record
;  $if	nc				; if space available		       ;AC000;
   JC D_$IF11
       mov  WORD PTR [di + rlr_sptr],bp	; store SFT offset
       mov  WORD PTR [di + rlr_sptr + 2],es ; store SFT offset
       mov  [di + rlr_fba + 2],ax
       mov  [di + rlr_fba],bx		; store lock range
       mov  [di + rlr_lba + 2],cx
       mov  [di + rlr_lba],dx

;	add to front of chain
;
;	(ds:si) = fwa MFT name record

       mov  ax,[si + mft_lptr]
       mov  [di + rlr_next],ax
       mov  [si + mft_lptr],di
;
; Set process ID of lock
;
proc_id equ Proc_ID	; NASM port label
       mov  ax,[ss:proc_id]
       mov  [di + rlr_pid],ax

;
;;     pop  bx				; recover lock type		       ;AN000;
;;     push bx				; restore the stack		       ;AN000;
;;     mov  [di].rlr_type,bx		; set the rlr_type field	       ;AN000;
       clc				; we finished OK

;  $else				;				       ;AC000;
   JMP SHORT D_$EN11
D_$IF11:

       mov  ax,error_lock_violation
       stc

;  $endif				;				       ;AC000;
D_$EN11:

;; pop	bx				;				       ;AN000;
   pop	ds
   pop	bp				;				       ;AC000;

   ret					; return - all set

   EndProc Set_Block

   BREAK <Clr_Block - Try to clear a lock>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Clr_Block - clear byte range lock on a file
;
;  FUNCTION:	   Clr_Block clears a lock on a specified range of a file.
;		   Locks are set via set_block.
;
;  INPUT:	   (ES:DI) = SFT address
;		   (CX:DX) = offset of area
;		   (SI:AX) = length of area
;		   (BX)    = 0 lock all operations
;			   = 1 lock write operations
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = DOSGroup
;
;  OUTPUT:	   Lock record removed for block specified.
;
;  REGISTERS USED: ALL but DS
;  (NOT RESTORED)
;
;  LINKAGE:	   Invoked by:	Clr_Mult_Block
;
;  EXTERNAL	   Invoke: CLP (SLE), OFL
;  REFERENCES:
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:	     (ax) = error code
;			       ('error_lock_violation' if conflicting locks or
;			       range does not exactly match previous lock)
;
;  CHANGE	04/15/87 - lock only write support
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Clr_Block
;
;	if file is SHARED and
;	if lock is valid and
;	if SFT matches and
;	if PROC_ID matches
;		if lock_reqest = lock_type
;			unchain the lock
;			put defunct lock on free chain
;			clear error status
;		else
;			set error status
;		endif
;	else
;		flush the stack
;		set error status
;	endif
;	if error
;		load return code
;	endif
;	return
;
;	END Clr_Block
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Clr_Block,NEAR

   ASSUME ES:NOTHING,DS:NOTHING

   Context DS
   push ds
;; push bx				; save type of operation	       ;AN000;
   cmp	word [es:di + sf_mft],ZERO

;  $if	nz,and				; if file is SHARED and 	       ;AC000;
   JZ D_$IF14

   push di
   call clp				; do common setup code

   ASSUME DS:NOTHING

   pop	bp				; ES:BP points to sft.
;; pop	bx				; recover the type of operation        ;AN000;

;  $if	c,and				; if lock exists and		       ;AC000;
   JNC D_$IF14
;  $if	z,and				; if range given correctly and	       ;AC000;
   JNZ D_$IF14
;
;	We've got the lock
;
;	(ds:di) = address of pointer (offset) to previous lock record
;	(es:BP) = sft address
;
; Now comes the tricky part.  Is the lock for us?  Does the lock match the SFT
; that was given us?  If not, then error.
;
   mov	si,[di] 			; (DS:SI) = address of lock record
   cmp	word ptr [si + rlr_sptr],bp

;  $if	z,and				; if SFT matches and		       ;AC000;
   JNZ D_$IF14

   mov	bp,es
   cmp	word ptr [si + rlr_sptr + 2],bp
;  $if	z,and				; (check both words of SFT pointer)    ;AC000;
   JNZ D_$IF14
   mov	bp,[ss:proc_id]
   cmp	[si + rlr_pid],bp

;; $if	z,and				; if PROC_ID matches		       ;AC000;
;  $if	z				; if PROC_ID matches		       ;AC006;
   JNZ D_$IF14
;
; Make sure that the type of request and the lock type match
;
;; cmp	bx,lock_all			;				       ;AN000;

;; $IF	E,OR				; if unlocking all or		       ;AN000;

;; mov	bp,[si].rlr_type		; get lock type 		       ;AN000;
;; cmp	bp,rlr_lall			; is it lock all?		       ;AN000;

;; $IF	NE				; if not a LOCK ALL lock	       ;AN000;
;
; The locks match the proper open invocation.  Unchain the lock
;
       mov  ax,[si + rlr_next]
       mov  [di],ax			; chain it out

;	put defunct lock record on the free chain
;
;	(ds:si) = address of freed lock rec

       mov  ax,[cs:Frelock]
       mov  [si + rlr_next],ax
       mov  [cs:Frelock],si
       clc

;  $else				; we have an error		       ;AC000;
   JMP SHORT D_$EN14
D_$IF14:

       stc

;  $endif				; Endif - an error		       ;AC000;
D_$EN14:

;  $if	c				; If an error was found 	       ;AC000;
   JNC D_$IF17

       mov  ax,error_lock_violation

;  $endif				; Endif - an error was found	       ;AC000;
D_$IF17:

   pop	ds				; restore DS

   ret


   EndProc Clr_Block

   BREAK <CLP - Common Lock Preamble>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   CLP - Common Lock Preamble
;
;  FUNCTION:	   This routine contains a common code fragment for set_block
;		   and clr_block.
;
;  INPUT:	   (ES:DI) = SFT address
;		   (CX:DX) = offset of area
;		   (SI:AX) = length of area
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = (DS) = DOSGroup
;
;  OUTPUT:	   (ds:si) = MFT address
;
;  REGISTERS USED: ALL but ES
;  (NOT RESTORED)
;
;  LINKAGE:	   Invoked by: Set_Block, Clr_Block
;
;  EXTERNAL	   Invoke: SLE
;  REFERENCES:
;
;  NORMAL	   'C' clear if no overlap
;  EXIT:	       (ax:bx) = offset of first byte in range
;		       (cx:dx) = offset of last byte in range
;
;  ERROR	   'C' set if overlap
;  EXIT:	   'Z' set if 1-to-1 match
;		       (di) points to previous lock
;
;  CHANGE	04/15/87 - lock only write support
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START CLP
;
;	shuffle arguments
;	if valid length
;		invoke SLE
;		set successful return status
;	else
;		set error return status
;	endif
;	return
;
;	END CLP
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure CLP,NEAR

   mov	bx,dx				; shuffle arguments
   xchg dx,ax
   xchg ax,cx				; (ax:bx) = offset
   mov	cx,si				; (cx:dx) = length

   or	si,dx				; see if length is 0

;  $if	nz,and				; if length is > 0 and		       ;AC000;
   JZ D_$IF19

   add	dx,bx
   adc	cx,ax				; (cx:dx) = lba+1

;  $if	nc,or				; no carry is ok		       ;AC000;
   JNC D_$LL19

   mov	si,dx
   or	si,cx

;  $if	z				; if !> 0 then			       ;AC000;
   JNZ D_$IF19
D_$LL19:

       sub  dx,1			; (cx:dx) = lba of locked region
       sbb  cx,0

       push cs
       pop  ds
;   (es:di) is sft
       push si
       mov  si,[es:di + sf_mft]
       push si
       mov  di,1			; Find own locks
SLE equ sle	; NASM port label
       call SLE
; di points to previous lock record
       pop  si
       pop  bp

;  $else				; we have an error		       ;AC000;
   JMP SHORT D_$EN19
D_$IF19:

       xor  si,si
       inc  si				; carry unchanged, zero reset
       mov  ax,error_lock_violation	; assume error
       stc

;  $endif				; endif - we have an error	       ;AC000;
D_$EN19:

   ret

   EndProc CLP

   BREAK <Chk_Block - See if the specified I/O violates locks>

;******************* START OF SPECIFICATIONS ***********************************
;
;  NAME:	   Chk_Block - check range lock on a file
;
;  FUNCTION:	   Chk_Block is called to interogate the lock status of a
;		   region of a file.
;
;  NOTE:	   This routine is called for every disk I/O operation
;		   and MUST BE FAST
;
;  INPUT:	   (ES:DI) points to an SFT structure
;		   (AL) = 80h - Write operation  = 0 - any non write operation
;		   (CX) is the number of bytes being read or written
;		   BytPos is a long (low first) offset into the file
;			      of the I/O
;		   User_ID = 16-bit user id of issuer
;		   Proc_ID = 16-bit process id of issuer
;		   (SS) = DOSGroup
;
;  OUTPUT:	   CF set according to status and presence of locks (see below)
;
;  REGISTERS USED: ALL	but ES,DI,CX,DS
;  (NOT RESTORED)
;
;  LINKAGE:	   IBMDOS Jump Table
;
;  NORMAL	   'C' clear if no error
;  EXIT:
;
;  ERROR	   'C' set if error
;  EXIT:	     (ax) = error code
;			       ('error_lock_violation' if conflicting locks)
;
;  CHANGE	04/15/87 - lock only write support
;  LOG:
;
;******************* END OF SPECIFICATIONS *************************************
;******************+ START OF PSEUDOCODE +**************************************
;
;	START Chk_Block
;
;	if shared SFT and
;	if locks exist
;		invoke SLE
;		if lock conflicts occur (error)
;			if this is !write operation and
;			if a write lock found
;				set successfull status
;			else
;				set error status
;			endif
;		else no error
;			flush stack
;		endif
;	endif
;
;	ret
;
;	END Chk_Block
;
;******************+  END  OF PSEUDOCODE +**************************************

   Procedure Chk_Block,NEAR

   ASSUME DS:NOTHING,ES:NOTHING,SS:DOSGROUP

write_op equ 080h			; write operation requested	       ;AN000;
lock_all equ 0h 			; lock all specified		       ;AN000;

;	PUSH	DS			;ICE
;	push	bx			;ICE
;	push	ax			;ICE

;	mov	bx,0140H		;ICE
;	xor	ax,ax			;ICE
;	mov	ds,ax			;ICE
;	mov	ax,word ptr [ds:bx]	;ICE
;	mov	word ptr [ds:bx],ax	;ICE

;	pop	ax			;ICE
;	pop	bx			;ICE
;	POP	DS			;ICE
   EnterCrit critShare

;  int 3
   nop
   nop

   PUSH ES
   PUSH DI
   PUSH CX
   PUSH DS
   cmp	word [es:di + sf_mft],0

;  $if	nz,and				; if the file is SHARED and	       ;AC000;
   JZ D_$IF22

   push cs
   pop	ds
   mov	si,[es:di + sf_MFT]		; (DS:SI) = address of MFT record
   test word [si + mft_lptr],-1

;  $if	nz,and				; if there are locks on this file and  ;AC000;
   JZ D_$IF22

   sub	cx,1				; (cx) = count-1
   cmc

;  $if	c				; there are bytes to lock	       ;AC000;
   JNC D_$IF22

;;     push ax				; preserve type of operation	       ;AN000;
					; DOS passes AL = 80 for writes
					;		= 00 for reads

       mov  ax,WORD PTR [ss:BytPos+2]
       mov  bx,WORD PTR [ss:BytPos]		; (ax:bx) = offset
       mov  dx,cx
       sub  cx,cx
       add  dx,bx
       adc  cx,ax			; (cx:dx) = lba of lock area
       sub  di,di			; ignore own locks
       call SLE
;;     pop  ax				; recover type of opperation	       ;AN000;

;   upon return DS:SI points to the RLR with the conflict

;;     $if  c				; if lock conflicts occur - error      ;AC000;

;   now we must check what type of lock exists
;   and the type of operation in progress.

;;	   cmp	al,write_op		;				       ;AN000;

;;	   $if	ne,and			; if NOT a write operation and	       ;AN000;

;;	   cmp	[si].rlr_type,rlr_lwr	;				       ;AN000;

;;	   $if	e			; if write locked (NOT all locked)     ;AN000;

;;	       clc			; then not true conflict - clear error ;AN000;

;;	   $else			; else it IS a valid conflict	       ;AC000;

;;	       stc			; true error - set error status

;;	   $endif			; endif - a valid conflict	       ;AC000;


;;     $endif				; endif -  conflicts		       ;AC000;

       mov  ax,error_lock_violation	; assume error

;  $endif				; endif - no need to check	       ;AC000;
D_$IF22:

;	exit
;
;	'C' and (ax) setup

   POP	DS
   POP	CX
   POP	DI
   POP	ES
   LeaveCrit critShare

   ret					; exit

   EndProc Chk_Block

   BREAK <MFT_get - get an entry from the MFT>

;******************* START OF SPECIFICATIONS ***********************************
;
;	MFT_get - get an entry from the MFT
;
;	MFT_get is used to return information from the MFT.  System utilities
;	use this capability to produce status displays.
;
;	MFT_get first locates the (BX)'th file in the list (no particular
;		ordering is promised).	It returns that name and the UID of
;		the (CX)'th SFT on that file and the number of locks on that
;		file via that SFT.
;
;	ENTRY	DS:SI point to DPL which contains:
;		(dBX) = zero-based file index
;		(dCX) = zero-based SFT index
;		(SS) = DOSGroup
;	EXIT	'C' clear if no error
;		  ES:DI buffer is filled in with BX'th file name
;		  (BX) = user id of SFT
;		  (CX) = # of locks via SFT
;		'C' set if error
;		  (ax) = error code
;			    ('error_no_more_files' if either index is out
;			     of range)
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure MFT_get,NEAR

;  int 3
   nop
   nop

   ASSUME DS:NOTHING,ES:NOTHING

   EnterCrit critShare
   MOV	BX,[SI + DPL_BX]
   MOV	CX,[SI + DPL_CX]
   Context ES
   MOV	DI,OFFSET OpenBuf wrt DOSGROUP

   xchg bx,cx				; (cx) = file index
   push cs
   pop	ds

   Off	SI,mft				; (ds:si) = fwa of OFFSET MFT

;	scan forward until next name

mget1: cmp byte [si + mft_flag],MFLG_FRE
   jz	mget3				; is free space
   jl	mget7				; is END

;	have another name.  see if this satisfies caller

   jcxz mget4				; caller is happy
   dec	cx
mget3: add si,[si + mft_len]		; skip name record
   JMP	SHORT mget1

;	we've located the file name.
;
;	(bx) = SFT index
;	(DS:SI) = MFT entry
;	(ES:DI) = address of caller's buffer

mget4: push di
   push si				; save table offset
   add	si,mft_name
mget5: lodsb
   stosb				; copy name into caller's buffer
   or	al,al
   jnz	mget5
   pop	si				; (DS:SI) = name record address
   xchg bx,cx				; (cx) = SFT chain count
   lds	di,[si + mft_sptr]
mget6: jcxz mget8			; have reached the SFT we wanted
   dec	cx
   lds	di,[di + sf_chain]		; get next link
   or	di,di
   jnz	mget6				; follow chain some more
   pop	di				; (es:di) = buffer address

;**	The file or SFT index was too large - return w/ error

mget7: mov ax,error_no_more_files
   stc
   LeaveCrit critShare

   ret

;**	We've got the SFT he wants.  Lets count the locks
;
;	(es:TOS) = buffer address
;	(DS:DI) = address of SFT
;	(si) = address of mft

mget8: mov ax,[DI + sf_flags]
   mov	dx,ds				; save segment
   push cs
   pop	ds
   mov	si,[si + mft_lptr]		; (DS:SI) = Lock record address
   sub	cx,cx				; clear counter

mget9: or si,si
   jz	mget11				; no more
   cmp	di,WORD PTR [si + rlr_sptr]
   jnz	mget10
   cmp	dx,word PTR [si + rlr_sptr + 2]
   jnz	mget10
   inc	cx
mget10: mov si,[si + rlr_next]
   JMP	SHORT mget9

;	Done counting locks.  return the info
;
;	(cx) = count of locks
;	(es:TOS) = buffer address

mget11: mov ds,dx
SF_UID equ sf_UID	; NASM port equate
   mov	bx,[di + SF_UID]			; (bx) = UID
   pop	di
   clc
   LeaveCrit critShare

   ret

   EndProc MFT_get

   BREAK <ASC - Add SFT to Chain>

;******************* START OF SPECIFICATIONS ***********************************
;
;	ASC - Add SFT to Chain
;
;	ASC is called to add an SFT to the front of the chain.
;
;	ASC checks the file share mode bits on the other SFTs in the chain and
;	reports a conflict.  The new SFT is NOT ADDED in the case of
;	conflicts.
;
;	ENTRY	(BX) = FBA MFT name record
;		(DS:SI) = SFT address
;	EXIT	'C' clear if added
;		    (ds:si) point to sft
;		    (bx) offset of mft
;		'C' set if conflict
;		  (ax) = error code
;	USES	ALL
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure ASC,NEAR

   cmp	word [si + sf_MFT],0
   jnz	asc9				; already on chain - internal error

;	The SFT looks good... lets see if there are any use conflicts

;	Message 1,<"Adding sft ">

   mov	ax,[ss:User_ID]			; place user information in SFT
   mov	[si + sf_UID],ax			; do it before CUC (he checks UID)
   mov	ax,[ss:Proc_ID]
   mov	[si + sf_PID],ax

   cmp	byte [cs:skip_check],1
;  $if	ne				;
   JE D_$IF24

       call CUC 			; check use conflicts

;  $endif
D_$IF24:

   jc	asc8				; use conflicts - forget it

;	MessageNum   AX

;	MessageNum   AX
;	Message 1,<" to ">
;	MEssageNum  DS
;	Message 1,<":">
;	MessageNum  SI
;	Message 1,<" ">

   mov	[si + sf_MFT],bx			; make SFT point to MFT

;	MessageNum  [si].sf_mft
;	Message 1,<13,10>

   mov	cx,[si + sf_mode] 		; (cx) = open mode
   mov	dx,ds				; (dx:si) = SFT address
   push cs
   pop	ds				; (ds:bx) = MFT address

;
;   Not special file and no previous sft found OR normal SFT.  We link it in
;   at the head of the list.
;
;   (dx:si) point to sft
;   (ds:bx) point to mft
;
   les	di,[bx + mft_sptr]		; get first link
   mov	word ptr [bx + mft_sptr],si	; link in this sft
   mov	word ptr [bx + mft_sptr + 2],dx	; link in this sft
   mov	ds,dx
   mov	word ptr [si + sf_chain],di
   mov	word ptr [si + sf_chain + 2],es
asc75: mov ds,dx			; point back to sft

   clc
asc8: ret

;	the SFT is already in use... internal error

asc9: push ax
   off	ax,ascerr
INTERR equ interr	; NASM port label
   call INTERR				; NEVER RETURNS
ascerr db "ASC: sft already in use", 13, 10, 0

   EndProc ASC


   BREAK <BCS - Bulk Close of SFTs>

;******************* START OF SPECIFICATIONS ***********************************
;
;	BCS - Bulk Close of SFTs
;
;	BCS scans the MFT structures looking for SFTs that match a UID (and
;	perhaps a PID).  The SFTs are closed.  The MFT name record is removed
;	if all its SFTs are closed.
;
;	BCS is called with a PID and a PID MASK.  The SFT is closed if its UID
;	matches the supplied UID AND (PID_ & PIDMASK) == PID_supplied
;
;	We walk the MFT structure closing all relevant SFT's. There is no
;	need for special handling of 70 handles or FCBs.
;
;	Note that we call DOS_close to close the SFT; DOS_close in turn calls
;	mftclose which may remove the SFT and even the MFT.  This means that
;	the MFT may vanish as we are working on it.  Whenever we call
;	DOS_close we'll know the next SFT and, if there is no next SFT we'll
;	know the next MFT.  (If the MFT were released a pointer to the carcass
;	is not of any help.  An MFT carcass cannot help find the next MFT
;	record)
;
;	ENTRY	(AX) = UID to match
;		(BX) = PID mask
;		(DX) = PID value
;	EXIT	'C' clear
;	USES	ALL
;
;******************* END OF SPECIFICATIONS *************************************

   ASSUME SS:DOSGROUP

   Procedure BCS,NEAR

   push cs
   pop	ds

   Off	SI,mft				; start at beginning of buffer

;	scan forward to the nearest name record (we may be at it now)
;
;	(DS:SI) = record pointer

bcs1: cmp byte [si + mft_flag],MFLG_FRE
   jl	bcs16				; at end of names, all done
   jg	bcs2				; have a name record

bcs1$5: add si,[si + mft_len]		; skip record and loop
   jmp	bcs1

bcs16: jmp bcs9
	nop	; identicalise

bcs2: les di,[si + mft_sptr]		; got name record - get first SFT
;	run down SFT chain
;
;	(es:di) = FBA next SFT
;	(ds:si) = FBA name record
;	(ax) = UID to match
;	(bx) = PID mask
;	(dx) = PID value

bcs3: or di,di
   jz	bcs1$5				; at end of SFT chain
   cmp	ax,[es:di + sf_UID]
   jnz	bcs4				; not a match
   mov	cx,[es:di + sf_PID]
   and	cx,bx				; apply mask
   cmp	cx,dx
   jz	bcs51				; got a match
bcs4:
   les	di,[es:di + sf_chain]
   JMP	bcs3				; chain to next SFT


;	We have an SFT to close
;
;	(es:di) = FBA SFT to be closed
;
;	(ds:si) = FBA name record
;	(ax) = UID to match
;	(bx) = PID mask
;	(dx) = PID value

bcs51: mov word [es:di + sf_ref_count],1
   push ax
   push bx
   push dx				; save ID values (ax,bx,dx) and mask
   push ds
   push si				; save name record address (ds:si)
   mov	si,word ptr [es:di + sf_chain]
   or	si,si
   jnz	bcs7				; isnt last sft, MFT will remain

;	yup, this is the last sft for this MFT, the MFT may evaporate.	we have
;	to find the next one NOW, and remember it

   pop	si				; undo saved name record address
   pop	ds
bcs6: add si,[si + mft_len]		; go to next guy
   cmp	byte [si + mft_flag],MFLG_FRE
   jz	bcs6				; must be a non-free guy
   push ds
   push si				; resave our new next MFT
   sub	si,si				; no next sft

;	Allright, we're ready to call the DOS.
;
;	(es:di)     = FBA sft to be closed
;	((sp))	 = long address of current or next MFT
;	((sp)+4) = PID value
;	((sp)+6) = PID mask
;	((sp)+8) = UID value

bcs7: mov WORD PTR [ss:ThisSFT],di
   mov	WORD PTR [ss:ThisSFT+2],es
   mov	es,word ptr [es:di + sf_chain + 2]
   SaveReg <es,si>
   call CPS				; clear JFN
   Context DS

multDos equ MultDOS	; NASM port equate
   CallInstall DOS_Close,multDos,1

   ASSUME DS:NOTHING

   RestoreReg <di,es>			; (es:DI) = offset of next sft
   pop	si
   pop	ds				; (DS:SI) = fwa of current or next MFT
   pop	dx
   pop	bx
   pop	ax
   or	di,di
   jnz	bcs85				; have more sft's
   JMP	bcs1				; look at this new MFT
bcs85: jmp bcs3

;	All Done

bcs9: clc

   ret

   EndProc BCS

   BREAK <CSL - Clear SFT Locks>

;******************* START OF SPECIFICATIONS ***********************************
;
;	CSL - Clear SFT Locks
;
;	CSL clears any locks associated with this SFT.
;
;	ENTRY	(ES:DI) = SFT address
;	EXIT	(ES:DI) unchanged
;	USES	All but ES,DI
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure CSL,NEAR

   mov	si,[es:di + sf_MFT]
   push cs
   pop	ds
   lea	bx,[si + mft_lptr]		; (DS:BX) = addr of lock ptr
   mov	si,[bx] 			; (DS:SI) = fba first lock record

;	scan the locks looking for belongers.
;
;	(es:di) = SFT address
;	(ds:si) = this lock address
;	(ds:bx) = address of link (offset value) to this lock (prev lock)

csl1: or si,si
   jz	csl3				; done with lock list
   cmp	di,word ptr [si + rlr_sptr]
   jnz	csl2				; not my lock
   mov	ax,es
   cmp	ax,word ptr [si + rlr_sptr + 2]
   jnz	csl2				; not my lock
;
; Make sure that the lock REALLY belongs to the correct process
;
   cmp	word [ss:user_in_ax], (ServerCall << 8) + 4 ; only check if   ; @@01
   jnz	csl15				; process specific; @@01
   mov	ax,[ss:Proc_ID]
   cmp	ax,[si + rlr_pid] 		; is process ID of lock = this PID?
   jnz	csl2				; nope, skip this lock

;	got a lock to remove

csl15:
   mov	dx,[si + rlr_next]
   mov	[bx],dx 			; link him out
   mov	ax,[cs:Frelock]
   mov	[si + rlr_next],ax
   mov	[cs:Frelock],si
   mov	si,dx				; (DS:SI) = next lock address
   JMP	SHORT csl1

   ERRNZ rlr_next			; lock is not ours... follow chain
csl2: mov bx,si
   mov	si,[si + rlr_next]
   JMP	SHORT csl1

;	All done

csl3: ret

   EndProc CSL

   ASSUME DS:NOTHING

   BREAK <CUC - check usage conflicts>

;******************* START OF SPECIFICATIONS ***********************************
;
;	Use conflict table
;
;	Algorithm:
;
;		if ((newmode == COMPAT) or (oldmode == COMPAT))
;			and (user ID's match)
;		   then accept
;		else
;		for new and old mode, compute index of (SH*3)+ACC
;		shift right table[new_index] by old_index+2;
;			'C' set if FAIL
;
;	The bit in the old_index position indicates the success or failure.  0
;	=> allow access, 1 => fail access
;
;******************* END OF SPECIFICATIONS *************************************

   PUBLIC CUCA

CUCA: DW 0ffffh 			; Compat    Read
   DW	0ffffh				; Compat    Write
   DW	0ffffh				; Compat    Read/Write
   DW	0ffffh				; Deny R/W  Read
   DW	0ffffh				; Deny R/W  Write
   DW	0ffffh				; Deny R/W  Read/Write
   DW	0df7fh				; Deny W    Read
   DW	0dbffh				; Deny W    Write
   DW	0dfffh				; Deny W    Read/Write
   DW	0beffh				; Deny R    Read
   DW	0b7ffh				; Deny R    Write
   DW	0bfffh				; Deny R    Read/Write
   DW	01c7fh				; Deny None Read
   DW	003ffh				; Deny None Write
   DW	01fffh				; Deny None Read/Write

;					     4443 3322 2111 000
;   Deny/Compat 			/    DDDD DDDD DDDD CCCx
;   DenyRead			       /	R RR	RRR
;   DenyWrite		  1st Access =< 	    WW WWWW
;   AccessRead			       \     R RR  RR  RR R R R
;   AccessWrite 			\    WW W W WW	WW  WW
;   x					     1111 1111 1111 1111
;   C  R    00				     1111 1111 1111 1111  ffff
;   C	W   01				     1111 1111 1111 1111  ffff
;   C  RW   02				     1111 1111 1111 1111  ffff

;   DRWR    10				     1111 1111 1111 1111  ffff
;   DRW W   11				     1111 1111 1111 1111  ffff
;   DRWRW   12				     1111 1111 1111 1111  ffff
;   D WR    20				     1101 1111 0111 1111  df7f

;   D W W   21				     1101 1011 1111 1111  dbff
;   D WRW   22				     1101 1111 1111 1111  dfff
;   DR R    30				     1011 1110 1111 1111  beff
;   DR	W   31				     1011 0111 1111 1111  b7ff

;   DR RW   32				     1011 1111 1111 1111  bfff
;   D  R    40				     0001 1100 0111 1111  1c7f
;   D	W   41				     0000 0011 1111 1111  03ff
;   D  RW   42				     0001 1111 1111 1111  1fff

;   In order to allow the greatest number of accesses, compatability read mode
;   is treated as deny-write read.  The other compatability modes are treated
;   as deny-both.

;******************* START OF SPECIFICATIONS ***********************************
;
;	CUC - check usage conflicts
;
;	CUC is called to see if a would-be open would generate a share
;	conflict with an existing open.  See CUCA for the algorithm and table
;	format.
;
;	ENTRY	(BX) = FBA MFT name record
;		(DS:SI) = SFT address
;	EXIT	'C' clear if OK
;		'C' set if conflict
;		  (ax) = error code
;	USES	ALL but arguments (BX, DS:SI)
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure CUC,NEAR

   push ds
   pop	es
   mov	di,si				; (es:di) = FBA SFT record
gom equ GOM	; NASM port label
   call gom				; get open mode
   mov	ch,al
   and	ch,sharing_mask 		; (ch) = new guy share
   jz	cuc0				; new guy is compatability mode
   mov	ch,sharing_mask
csi equ CSI	; NASM port label
cuc0: call csi				; compute share index
   add	ax,ax				; *2 for word index
   xchg ax,si				; (si) = share table index
   push cs
   pop	ds				; (ds:bx) = FBA MFT record
   mov	dx,WORD PTR [cs:CUCA + si]		; (dx) = share mask
   lds	si,[bx + mft_sptr]		; (ds:si) = first sft guy

;	ready to do access compares.
;
;	(ds:si) = address of next sft
;	(es:di) = address of new  sft
;	(dx) = share word from CUCA
;	(cs:bx) = MFT offset
;	(ch) = 0 if new SFT is compatibilty mode, else sharing_mask

cuc1: or si,si
   jz	cuc9				; at end of chain, no problems
   call gom				; if not FCB, then mode in al is good
   mov	ah,al
   and	ah,sharing_mask 		; (ah) = sharing mode
   or	ah,ch				; (ah) = 0 iff new and old is SH_COMP
   jnz	cuc2				; neither is SH_COMP

;	Both the old and the new guy are SH_COMP mode.	If the UIDs match,
;	step onward.  If they don't match do normal share check.

   mov	bp,[es:di + sf_UID]
   cmp	bp,[si + sf_UID]
   jz	cuc20				; equal => next sft to check

cuc2: call csi				; compute the share index
   inc	ax
   inc	ax
   xchg al,cl				; (cl) = shift count
   mov	ax,dx
   sar	ax,cl				; select the bit
   jc	cuc8				; a conflict!
cuc20:
   lds	si,[si + sf_chain]
   JMP	cuc1				; chain to next SFT and try again

;	Have a share conflict

cuc8: mov ax,error_sharing_violation	; assume share conflict
   stc

;	done with compare.  Restore regs and return
;
;	'C' set as appropriate
;	(es:di) = new SFT address
;	(ax) set as appropriate
;	(bx) = MFT offset

cuc9: push es
   pop	ds
   mov	si,di

   ret

   EndProc CUC

   BREAK <csi - compute share index>

;******************* START OF SPECIFICATIONS ***********************************
;
;	csi - compute share index
;
;
;	If the mode byte has a leading 7 then it is interpreted as a 0
;	csi turns a mode byte into an index from 0 to 14:
;
;		(share index)*3 + (access index)
;
;	ENTRY	(al) = mode byte
;	EXIT	(ax) = index
;	USES	AX, CL
;
;******************* END OF SPECIFICATIONS *************************************

   Procedure CSI,NEAR

   mov	ah,al
   and	ah,access_mask			; (ah) = access bits
   and	al,sharing_mask 		; (al) = share bites
   ERRNZ sharing_mask-0F0h
   cmp	al,sharing_net_FCB
   jnz	csi1
   xor	al,al
csi1:
   shr	al,1
   shr	al,1
   shr	al,1
   mov	cl,al				; (cl) = SHVAL*2
   shr	al,1
   add	al,cl				; (al) = SHVAL*3
   add	al,ah				; (al) = SH*3 + ACC
   sub	ah,ah

   ret

   EndProc CSI

   Break <GOM - get open mode>

;******************* START OF SPECIFICATIONS ***********************************
;
;	GOM - get open mode
;
;   Find the correct open mode given the encoded sf_mode.  Note that files
;   marked READ-ONLY and are opened in compatability read-only are treated as
;   deny-write read-only.  FCB opens are sharing_compat open_for_both and
;   net FCB opens are sharing_compat
;
;	Entry:	    (DS:SI) points to SFT
;   Exit:	(AL) has correct mode
;   Uses:	(AX)
;******************* END OF SPECIFICATIONS *************************************

   Procedure GOM,NEAR

   mov	ax,[si + sf_mode]
sf_IsFCB equ sf_isfcb	; NASM port equate
   TEST AX,sf_IsFCB
   jz	gom1				; if not FCB, then mode in al is good
   mov	al,sharing_compat+open_for_both
gom1:
   mov	ah,al
   and	ah,sharing_mask
   cmp	ah,sharing_net_FCB		; is sharing from net FCB?
   jnz	gom2				; no, got good mode
   and	al,access_mask			; yes, convert to compat mode sharing
   or	al,sharing_compat
;
; The sharing mode and access mode in AL is now correct for the file.  See if
; mode is compatability.  If so and file is read-only, convert access mode to
; deny-write read.
;
gom2:
   mov	ah,al
   and	ah,sharing_mask
   retnz				; not compatability, return.
   test byte [si + sf_attr],attr_read_only
   retz 				; not read-only
   mov	al,sharing_deny_write + open_for_read

   ret

   EndProc GOM
