NetBoot/BootWrapper.a
2020-11-02 10:58:05 +08:00

510 lines
17 KiB
Plaintext

myUnitNum equ 52
myDRefNum equ ~myUnitNum
Code
cmp.l #1,4(SP)
beq getBootBlocks
cmp.l #2,4(SP)
beq getSysVol
cmp.l #3,4(SP)
beq mountSysVol
move.l #-1,d0
rts
getBootBlocks
lea DiskImage,A0
move.l 8(SP),A1 ; Inside the global struct...
add.l #$BA,A1 ; ...is an element for the structured part of the boot blocks
move.l #138,D0 ; ...of this length
dc.w $A22E ; _BlockMoveData
; If these boot blocks are executable (from offset 2), then the 138 bytes of
; declarative data copied by the netBOOT driver are not enough. We edit the boot
; blocks with a stub that copies the entire 1k into place. System 7 needs this.
move.b 6(A1),D0 ; BBVersion
cmp.b #$44,D0
beq.s executableBB
and.b #$C0,D0
cmp.b #$C0,D0
beq.s executableBB
bra return
executableBB ; Need to leave bytes 6,7 intact
move.l #$60000004,2(A1) ; BB+2: BRA.W BB+8
move.w #$4EB9,8(A1) ; BB+8: JSR fixBB
lea fixBB,A0
move.l A0,10(A1)
move.l A1,A0 ; Clear the icache with a BlockMove
move.l #138,D0
dc.w $A02E ; _BlockMove
bra return
fixBB ; The BB stub JSRs to here
move.l (SP)+,A1
sub.l #14,A1 ; "Rewind" to the start of the BB
lea DiskImage,A0 ; Replace stub BB with correct BB
move.l #$400,D0
dc.w $A02E ; _BlockMove
jmp 2(A1) ; Jump to the fixed-up BB
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
getSysVol
; Our register conventions:
; A2 = fake dqe; A3 = dce; A4 = copied driver
link A6,#-$32
movem.l A2-A4/D3,-(SP)
; Now I copy all this stuff under BufPtr (because this current location will disappear)
lea Code,A0
dc.w $A021 ; _GetPtrSize
; Save a copy of the image size for later
move.l D0,D1
sub.l #DiskImage-Code,D1
lea DiskImageSize,A1
move.l D1,(A1)
; Make space in "high memory" for the combined driver and disk image
sub.l #BufPtrCopy-Code,D0
sub.l D0,$10C ; BufPtr
move.l $10C,A4 ; ... into A4
; Copy the driver and image as one chunk
lea BufPtrCopy,A0
move.l A4,A1
dc.w $A22E ; _BlockMoveData
; Truncate this block to reduce heap fragmentation
lea Code,A0
move.l #BufPtrCopy-Code,D0
dc.w $A020 ; _SetPtrSize
; Install the driver in the unit table
move.l #myDRefNum,D0
dc.w $A43D ; _DrvrInstall ReserveMem
bne error
; Get DCE handle of installed driver
move.l $11C,A0 ; UTableBase
add.l #myUnitNum*4,A0
move.l (A0),A3
; Lock it down
move.l A3,A0
dc.w $A029 ; _HLock
; Populate the empty DCE that DrvrInstall left us
move.l (A3),A0 ; A0 = dce ptr
move.l A4,0(A0) ; dCtlDriver is pointer (not hdl)
move.w 0(A4),D0 ; drvrFlags
and.w #~$0040,D0 ; Clear dRAMBased bit (to treat dCtlDriver as a pointer)
move.w D0,4(A0) ; dCtlFlags
; Copy these other values that apparently the Device Mgr forgets
move.w 2(A4),$22(A0) ; drvrDelay to dCtlDelay
move.w 4(A4),$24(A0) ; drvrEMask to dCtlEMask
move.w 6(A4),$26(A0) ; drvrMenu to dCtlMenu
; Open the driver
lea -$32(A6),A0
bsr clearblock
lea DrvrNameString,A1
move.l A1,$12(A0) ; IOFileName
dc.w $A000 ; _Open
bne error
; Create a DQE
move.l #$16,D0
dc.w $A71E ; _NewPtr ,Sys,Clear
bne error
add.l #4,A0 ; has some cheeky flags at negative offset
move.l A0,A2
; Point our caller to the fake dqe
move.l 4+12(A6),A1
move.l A2,(A1)
; Find a free drive number (nicked this code from BootUtils.a:AddMyDrive)
LEA $308,A0 ; [DrvQHdr]
MOVEQ #4,D3 ; start with drive number 4
CheckDrvNum
MOVE.L 2(A0),A1 ; [qHead] start with first drive
CheckDrv
CMP.W 6(A1),D3 ; [dqDrive] does this drive already have our number?
BEQ.S NextDrvNum ; yep, bump the number and try again.
CMP.L 6(A0),A1 ; [qTail] no, are we at the end of the queue?
BEQ.S GotDrvNum ; if yes, our number's unique! Go use it.
MOVE.L 0(A1),A1 ; [qLink] point to next queue element
BRA.S CheckDrv ; go check it.
NextDrvNum
; this drive number is taken, pick another
ADDQ.W #1,D3 ; bump to next possible drive number
BRA.S CheckDrvNum ; try the new number
GotDrvNum
; Populate the DQE
move.l #$80080000,-4(A2) ; secret flags, see http://mirror.informatimago.com/next/developer.apple.com/documentation/mac/Files/Files-112.html
move.w #1,4(A2) ; qType
move.w #0,$A(A2) ; dQFSID should be for a native fs
move.l DiskImageSize,D0
swap D0
move.l D0,$C(A2) ; dQDrvSz/dQDrvSz2
lea gDQEAddr,A0
move.l A2,(A0)
; Into the drive queue (which will further populate the DQE)
move.l A2,A0 ; A0 = DQE ptr
move.w D3,D0
swap.w D0 ; D0.H = drive number
move.w #myDRefNum,D0 ; D0.L = driver refnum
dc.w $A04E ; _AddDrive
bne error
; Save this most precious knowledge for later
lea gDriveNum,A0
move.w D3,(A0)
; Work around a bug in the .netBOOT ToExtFS hook
bsr fixDriveNumBug
; Clean up our stack frame
movem.l (SP)+,A2-A4/D3
unlk A6
bra return
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
mountSysVol
link A6,#-$32
movem.l A2-A4/D3,-(SP)
lea gDriveNum,A0
move.w (A0),D3
; System 7 needs MountVol to return the right vRefNum
move.l $366,A0 ; Steal existing PB from FSQHead
; Set aside the FS queue to stop MountVol deadlocking
move.w $360,-(SP) ; FSBusy
move.l $362,-(SP) ; FSQHead
move.l $366,-(SP) ; FSQTail
clr.w $360
clr.l $362
clr.l $366
; MountVol
bsr clearblock
move.w D3,$16(A0) ; ioVRefNum = ioDrvNum = the drive number
dc.w $A00F ; _MountVol
bne error
; Restore the FS queue
move.l (SP)+,$366
move.l (SP)+,$362
move.w (SP)+,$360
; Tattle about the DQE and VCB
move.l 4+12(A6),A1
move.l $356+2,A0 ; VCBQHdr.QHead (maybe I should be clever-er)
move.l A0,(A1)
move.l 4+16(A6),A1
lea gDQEAddr,A0
move.l (A0),(A1)
movem.l (SP)+,A2-A4/D3
unlk A6
return
move.l #0,d0
rts
error
dc.w $A9C9
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; The .netBOOT driver installs a ToExtFS hook that triggers on _MountVol
; and calls our mountSysVol. The hook routine checks that the drive number
; is 4. On machines with >2 existing drives, this check fails, and we
; never get called (i.e. Mini vMac).
; The solution is to head patch the .netBOOT ToExtFS hook. We use a
; one-shot patch on _MountVol to gain control after the hook is installed
; but before it is called, and install our new hook.
bystanderTrap equ $A00F ; _MountVol
gTheirDriveNum dc.w 0
gOrigBystanderTrap dc.l 0
gOrigExtFS dc.l 0
NetBootName dc.b 8, ".netBOOT", 0
fixDriveNumBug
; Get the .netBOOT driver refnum (only to search for the right drive)
lea -$32(A6),A0 ; Use our caller's stack frame
bsr clearblock
lea NetBootName,A1
move.l A1,$12(A0) ; IOFileName
dc.w $A000 ; _Open
bne error
move.w $18(A0),D0 ; Result in IORefNum
; Search for the drive with that number in dQRefNum
lea $308,A1 ; DrvQHdr
lea 2(A1),A0 ; Treat qHead like qLink.
nbFindLoop move.l (A0),A0 ; follow qLink
cmp.w 8(A0),D0 ; is the dQRefNum the .netBOOT driver?
beq.s nbFound ; then we found the .netBOOT drive
cmp.l 6(A1),A0 ; have we reached qTail?
beq error ; then we didn't find the .netBOOT drive
bra.s nbFindLoop
nbFound move.w 6(A0),D0 ; Get dqDrive (drive number)
; Save drivenum in a global for our patch to use
lea gTheirDriveNum,A0
move.w D0,(A0)
; Only install the patch if we need to
cmp.w #4,D0 ; A drivenum of 4 will work anyway
bne installOneshotPatch
rts
; Install a self-disabling patch on _MountVol
installOneshotPatch
move.w #bystanderTrap,D0 ; Save original in a global
dc.w $A346 ; _GetOSTrapAddress
lea gOrigBystanderTrap,A1
move.l A0,(A1)
move.w #bystanderTrap,D0 ; Install
lea oneshotPatch,A0
dc.w $A247 ; _SetOSTrapAddress
rts
; Our _MountVol patch
oneshotPatch
clr.l -(SP)
movem.l D0/D1/A0/A1,-(SP) ; Save "OS trap" registers
move.l $3F2,A0 ; Save the ToExtFS hook in a global to call later
lea gOrigExtFS,A1
move.l A0,(A1)
lea toExtFSPatch,A0 ; Install the ToExtFS head patch
move.l A0,$3F2
lea gOrigBystanderTrap,A0 ; Remove this patch from _MountVol
move.l (A0),A0
move.l A0,16(SP)
move.w #bystanderTrap,D0
dc.w $A047 ; _SetTrapAddress
movem.l (SP)+,D0/D1/A0/A1
rts
; Our head patch on the ToExtFS hook
toExtFSPatch
movem.l A0-A4/D1-D2,-(SP) ; Save the same registers at the real ToExtFS hook
cmp.b #$F,$6+1(A0) ; Check for a _MountVol call (IOTrap+1)
bne.s hookReturn
lea gTheirDriveNum,A1 ; Check for the CORRECT drive number,
move.w (A1),D0 ; instead of erroneously checking for 4.
cmp.w $16(A0),D0 ; IODrvNum
bne.s hookReturn
lea gOrigExtFS,A1 ; Rejoin the ToExtFS hook AFTER the buggy code
move.l (A1),A1
hookScan add.l #2,A1 ; Scan for "lea DrvQHdr,A2" (or similar)
cmp.w #$308,2(A1)
bne.s hookScan
jmp (A1) ; and enter at that point
hookReturn movem.l (SP)+,A0-A4/D1-D2
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
clearblock
move.w #$32/2-1,D0
.loop clr.w (A0)+
dbra D0,.loop
lea -$32(A0),A0
rts
DrvrNameString
dc.b 11, ".netRamDisk"
gDriveNum dc.w 0
gDQEAddr dc.l 0
; code on this side is for start only, and stays in the netBOOT driver globals until released
BufPtrCopy
; code on this side gets copied beneath BufPtr (is that the best place??)
; Shall we start with a driver?
DrvrBase
dc.w $4F00 ; dReadEnable dWritEnable dCtlEnable dStatEnable dNeedLock
dc.w 0 ; delay
dc.w 0 ; evt mask
dc.w 0 ; menu
dc.w DrvrOpen-DrvrBase
dc.w DrvrPrime-DrvrBase
dc.w DrvrControl-DrvrBase
dc.w DrvrStatus-DrvrBase
dc.w DrvrClose-DrvrBase
dc.b 11, ".netRamDisk"
; a0=iopb, a1=dce on entry to all of these...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrOpen
move.w #0,$10(A0) ; ioResult
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrPrime
movem.l A0-A1/D0-D1,-(SP)
cmp.b #2,$7(A0) ; ioTrap == aRdCmd
bne.s notRead
; D1 = image offset
move.l $10(A1),D1 ; Device Mgr gives us dCtlPosition
; D0 = number of bytes
move.l $24(A0),D0 ; ioReqCount
move.l D0,$28(A0) ; -> ioActCount
; Do the dirty (we are just about to trash A0, so use it first)
move.w #0,$10(A0) ; ioResult
move.l $20(A0),A1 ; ioBuffer
lea DiskImage,A0
add.l D1,A0
dc.w $A22E ; _BlockMoveData
bra.s primeFinish
notRead
cmp.b #3,7(A0) ; ioTrap == aRdCmd
bne.s primeFinish
; D1 = image offset
move.l $10(A1),D1 ; Device Mgr gives us dCtlPosition
; D0 = number of bytes
move.l $24(A0),D0 ; ioReqCount
move.l D0,$28(A0) ; -> ioActCount
; Do the dirty (we are just about to trash A0, so use it first)
move.w #0,$10(A0) ; ioResult
move.l $20(A0),A0 ; ioBuffer
lea DiskImage,A1
add.l D1,A1
dc.w $A22E ; _BlockMoveData
primeFinish
movem.l (SP)+,A0-A1/D0-D1
bra DrvrFinish
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrControl
move.w #-18,$10(A0) ; ioResult
bra DrvrFinish
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrStatus
cmp.w #6,$1A(A0)
beq.s status_fmtLstCode
cmp.w #8,$1A(A0)
beq.s status_drvStsCode
bra.s status_unknown
status_fmtLstCode ; tell them about our size
move.l A2,-(SP)
move.w #1,$1C(A0)
move.l $1C+2(A0),A2
move.l DiskImageSize,0(A2)
move.l #$40000000,4(A2)
move.l (SP)+,A2
move.w #0,$10(A0) ; ioResult = statusErr
bra DrvrFinish
status_drvStsCode ; tell them about some of our flags
move.w #0,$1C(A0) ; csParam[0..1] = track no (0)
move.l #80080000,$1C+2(A0) ; csParam[2..5] = same flags as dqe
move.w #0,$10(A0) ; ioResult = noErr
bra DrvrFinish
status_unknown
move.w $1A(A0),D0 ; dodgy, for debugging
add.w #$3000,D0
dc.w $A9C9
move.w #-18,$10(A0) ; ioResult
bra DrvrFinish
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrClose
move.w #$4444,D0
dc.w $A9C9
move.w #0,$10(A0) ; ioResult
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DrvrFinish
move.w 6(A0),D1 ; iopb.ioTrap
btst #9,D1 ; noQueueBit
bne.s DrvrNoIoDone
move.l $8FC,-(SP) ; jIODone
DrvrNoIoDone
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DiskImageSize
dc.l 0
align 9
DiskImage