.TITLE FILFIX FIX A LOCKED FILE
;
;  MCR TASK TO RECONSTRUCT A FILE CORRUPTED BY AN ABORTED TASK.
;
;  WRITTEN NOVEMBER 1976 R B FRENCH THE BOEING COMPANY
;  UPDATED BY ROMAN ROMANETTI
;  UPDATED BY MIKE BLAKE-KNOX
;
;  CALLING SEQUENCE
;
;  MCR>FIL[FIX]  FNAME
;	FNAME = NAME OF CORRUPTED FILE
;
;  PATCH WILL UNLOCK THE FILE.  IF LOCKED.  INLESS IT IS LOCKED DUE
;  TO WRITE ACCESS BY AN ACTIVE TASK.  THE FILE WILL THEN BE SCANNED
;  TO DETERMINE CERTAIN CRITICAL ATTRIBUTES ANSD THE CORRECT VALUES OF 
;  THE ATTRIBUTES WILL BE WRITTEN IN THE FILE HEADER.
;
;  TASK BUILD FILE
;
;  FILFIX/-FP=FILFIX
;  /
;  TASK=...PAT
;  UNITS =2
;  ASG=TI:2
;  PRI=60
;  STACK=21
;  //
;
	.MCALL  GCMLB$,GCML$,CSI$,CSI$1,CSI$2,DIR$,QIOW$
	.MCALL  FINIT$,FSRSZ$,FDBDF$,FDOP$A,OPEN$U,CLOSE$,EXIT$S
	.MCALL  FDRC$A,FHDOF$,GET$
	FHDOF$  DEF$L			;DEFINE FILE HEADER OFFSETS
SERR:
	JMP  SYNERR
FERR:
	JMP  FCSERR
PATCH:
	FINIT$				;INITIALIZE FSR
;
;  READ AND RECODE THE COMMAND LINE
START:
	GCML$  #GCLBLK			;GET COMMAND LINE
	BCC  10$
	CMPB  #GE.EOF,GCLBLK+G.ERR	;END OF FILE?
	BNE  SERR			;SYNTAX ERROR IF NOT
	EXIT$S
10$:
	CSI$1  #CSIBLK,GCLBLK+G.CMLD+2,GCLBLK+G.CMLD  ;CHECK SYNTAX
	BCS  SERR
	CSI$2  #CSIBLK,OUTPUT		;DECODE IT
	BCS  SERR			;SYNTAX ERROR IF NOT OKAY
	MOV  #FDB,R0			;FDB ADDRESS IN R0
	MOV  #FDB+F.FNB,R1		;FNB ADDRESS IN R1
	MOV  #CSIBLK+C.DSDS,R2		;DATASET POINTER IN R2
	CLR  R3
	JSR  PC,.PARSE			;PARSE THE FDB
	BCS  FERR
	JSR  PC,.FIND			;FIND THE FILE
	BCC  20$
	CMPB #IE.NSF,FDB+F.ERR		;IS NO SUCH FILE?
	BNE  FERR
	JMP  NOFILE
;
;  READ THE FILE HEADER AND UNLOCK THE FILE,  IF LOCKED AND
;  NOT BEING ACCESSED.
20$:
	DIR$  #READ			;READ THE FILE HEADER
	BCS  FERR			;CHECK FOR ERRORS
	MOV  #RDSTAT,READ+Q.IOPL+2	;SET UP TO READ STATISTICS BLOCK
	DIR$  #READ			;READ STATISTICS BLOCK
	BCS  FERR
	BITB  #100,HEADER+H.UCHA	;IS FILE LOCKED?
	BEQ  OPEN			;BRANCH IF NOT
	TST  STAT+10			;IS FILE CURRENTLY IN USE?
	BEQ  .+6
	JMP  FILUSE
	BIC  #100,HEADER+H.UCHA		;CLEAR FILE LOCKED BIT
	DIR$  #WRITE			;WRITE THE CHARACTERISTICS BLOCK
	BCS  FERR			;CECK IF ALL OK
;
;OPEN THE FILE AND PUT ACTUAL ATTRIBUTE VALUES IN THE FDB.
OPEN:
	OPEN$U  #FDB			;OPEN THE FILE
	BCC  5$
	JMP  FCSERR
5$:
	MOV STAT+4,FDB+F.HIBK		;UPDATE HIGH BLOCK
	MOV STAT+6,FDB+F.EFBK+2		;AND
	MOV STAT+4,FDB+F.EFBK		;END OF FILE BLOCK
	MOV STAT+6,FDB+F.HIBK+2		;FROM STATISTICS BLOCK INFORMATION
	TST FDB+F.FFBY			;IS END OF FILE BYTE DEFINED?
	BNE 10$
	MOV #1000,FDB+F.FFBY		;IF NOT, MAKE IT 1000
10$:
	TST FDB+F.RSIZ			;IS RECORD SIZE DEFINED?
	BNE 20$
	MOV #1000,FDB+F.RSIZ		;IF NOT MAKE IT 1000
20$:
	CMPB  #R.FIX,FDB+F.RTYP		;FIXED LENGTH RECORDS?
	BEQ  CLOSE			;IF SO, JUST CLOSE THE FILE
	MOV  #FDB+F.FNB,R1		;CLOSE...AND..
	MOV #HEADER,R2
	MOV #30.,R3
50$:
	MOVB  (R1)+,(R2)+
	SOB R3,50$
	CLOSE$  #FDB
	MOV #FDB+F.FNB,R1		;MOVE NAME BLOCK BACK
	MOV #HEADER,R2
	MOV  #30.,R3
60$:
	MOVB  (R2)+,(R1)+
	SOB R3,60$
	OPEN$U  #FDB			;OPEN,OTHERWISE E-O-F TO FIRST GET
	BCS  FCSERR
;
;  SCAN THE FILE TO DETERMINE MAXIMUM RECORD SIZE.  CONTINUE SCAN 
;  UNTIL AN ERROR OCCURS.
	CLR  R1
SCAN:
	GET$			;GET A RECORD
	BCS  25$
	MOV  FDB+F.VBN+2,R3
	MOV  FDB+F.NRBD+2,R2	;GET POINTER TO LAST RECORD
	CMP  R2,FDB+F.BDB	;IS IT IN BLOCK BUFFER OR USER BUF
	BLT  10$
	SUB  FDB+F.BDB,R2	;SUBTRACT START OF BLOCK BUFFER
	SUB  #S.BFHD,R2		;ACCOUNT FOR BUFFER HEADER
	SUB  #2,R2		;OFFSET FOR COUNTER
	MOV  R2,FFB
	MOV  R3,VBN
10$:
	MOV  FDB+F.NRBD,R4	;RECORD SIZE
	ADD  #1,R4		;FOR ODD SIZE
	ASR  R4
	ASL  R4
	MOV  FFB,R5
	ADD  R4,FFB		;FFBYTE AFTER THIS
	ADD  #2,FFB		;RECORD
15$:
	CMP  FFB,#1000		;NEXT BLCK?
	BLE  20$
	MOV  R5,FFB2		;YES.  LAST GOOD BLOCK
	MOV  VBN,VBN2
17$:
	SUB  #1000,FFB
	ADD  #1,VBN
	CMP  FFB,#1000
	BGT  17$
20$:
	CMP  R1,R4		;RECORD GREATER?
	BGE  SCAN
	MOV  R4,R1		;YES
	BR  SCAN
25$:
	CMPB  #IE.EOF,FDB+F.ERR	;EOF?
	BEQ 30$
	MOV  FFB2,FDB+F.FFBY	;NO.  E-O-F TO LAST GOOD BLOCK
	MOV  VBN2,FDB+F.EFBK+2
	BR  40$
30$:
	MOV  FFB,FDB+F.FFBY	;YES.  E-O-F TO LAST BLOCK
	MOV  VBN,FDB+F.EFBK+2
40$:
	MOV  R2,FDB+F.RSIZ	;UPDATE RECORD SIZE IN FDB
	BR  CLOSE
VBN:	.WORD 1
VBN2: .WORD 1
FFB:  	.WORD 0
FFB2:	.WORD 0
;
;  PUT CORRECT ATTRIBUTE VALUES IN THE FDB AND CLOSE THE FILE
CLOSE:
	CLOSE$	#FDB			;CLOSE THE FILE
	JMP  START
;
;  ERROR MESSAGES
NOFILE:
	MOV  #NFLMSG,QIOW+Q.IOPL
	MOV  #14.,QIOW+Q.IOPL+2
	BR SYNERR
FILEMP:
	MOV	#FLEMSG,QIOW+Q.IOPL
	MOV	#12.,QIOW+Q.IOPL+2
	BR  SYNERR
FILUSE:
	MOV  #FLUMSG,QIOW+Q.IOPL
	MOV  #21.,QIOW+Q.IOPL+2
	BR  SYNERR
FCSERR:
	MOV  #FCSMSG,QIOW+Q.IOPL
	MOV  #15.,QIOW+Q.IOPL+2
	MOV  #FCSMSG+13,R0
	MOVB  FDB+F.ERR,R1
	CLR   R2
	JSR  PC,$CBDSG
SYNERR:
	DIR$  #QIOW
	JMP  START
QIOW:
	QIOW$  IO.WLB,3,2,,,,<SYNMSG,14.,0>
SYNMSG:  .ASCII  <12>/SYNTAX ERROR/<15>
FCSMSG:  .ASCII  <12>/FCS ERROR /<15>
FLUMSG:  .ASCII  <12>/FILE BEING ACCESSED/<15>
FLEMSG:  .ASCII  <12>/FILE EMPTY/<15>
NFLMSG:  .ASCII  <12>/NO SUCH FILE/<15>
	 .EVEN
;
;COMMAND LINE MACROS AND DATA BLOCKS
GCLBLK:
	GCMLB$	1,FIL,HEADER,2
	CSI$
	.EVEN
CSIBLK:  .BLKB  C.SIZE			;CSI BLOCK
;
;  BLOCKS TO READ/WRITE FILE HEADER INFORMATION.
READ:
	QIOW$  IO.RAT,1,1,,IOSB,,<FDB+F.FNB,RDHDR>
WRITE:
	QIOW$  IO.WAT,1,1,,IOSB,,<FDB+F.FNB,WRCHAR>
IOSB:
	.BLKW  2
RDHDR:  .BYTE  -12,0		;BLOCK TO READ FILE HEADER
	.WORD HEADER
	.WORD 0
RDSTAT:  .BYTE  -11,12		;BLOCK TO READ STATICS BLOCK
	.WORD  STAT
	.WORD	0
WRCHAR:  .BYTE  3,1		;BLOCK TO WRITE FILE CHARACTERIST
	.WORD HEADER+H.UCHA
	.WORD 0
HEADER:  .BLKB  1000
STAT:   .BLKW  5		;BUFFER FOR STATISTICS BLOCK
;
;  I/O MACROS AND DATA BLOCKS
	FSRSZ$  1		;SET UP FOR ONE LUN
FDB:
	FDBDF$			;START OF FDB
	FDOP$A  1,CSIBLK+C.DSDS
	FDRC$A  FD.PLC,HEADER,1000
;
	.END PATCH