restore_usa:
; Update Sequence Array restore
mov bx, [di+4]
mov cx, [di+6]
inc bx
add bx, di
inc bx
add di, 1feh
dec cx
@@:
mov ax, [bx]
stosw
inc bx
inc bx
add di, 1feh
loop @b
ret
find_attr:
; in: di->file record, ax=attribute
; out: di->attribute or di=0 if not found
add di, [di+14h]
.1:
; attributes codes are formally dwords, but all they fit in word
cmp word [di], -1
jz .notfound
cmp word [di], ax
jnz .continue
; for $DATA attribute, scan only unnamed
cmp ax, 80h
jnz .found
cmp byte [di+9], 0
jz .found
.continue:
add di, [di+4]
jmp .1
.notfound:
xor di, di
.found:
ret
process_mcb_nonres:
; in: si->attribute, es:di->buffer
; out: di->buffer end
add si, [si+20h]
xor ebx, ebx
.loop:
lodsb
test al, al
jz .done
push invalid_read_request_string
movzx cx, al
shr cx, 4
jz find_error_sp
xchg ax, dx
and dx, 0Fh
jz find_error_sp
add si, cx
add si, dx
pop ax
push si
dec si
movsx eax, byte [si]
dec cx
jz .l1e
.l1:
dec si
shl eax, 8
mov al, [si]
loop .l1
.l1e:
xchg ebp, eax
dec si
movsx eax, byte [si]
mov cx, dx
dec cx
jz .l2e
.l2:
dec si
shl eax, 8
mov al, byte [si]
loop .l2
.l2e:
pop si
add ebx, ebp
; eax=length, ebx=disk block
stosd
mov eax, ebx
stosd
jmp .loop
.done:
xor eax, eax
stosd
ret
load_attr:
; in: ax=attribute, es:bx->buffer, di->base record
; out: bx->buffer end; CF set if not found
push di
push ax
mov byte [es:bx], 1
inc bx
push bx
mov [ofs], bx
; scan for attrubute
add di, [di+14h]
@@:
call find_attr.1
test di, di
jz .notfound1
cmp byte [di+8], 0
jnz .nonresident
; resident attribute
mov si, di
pop di
dec di
mov al, 0
stosb
mov ax, [si+10h]
stosw
xchg ax, cx
add si, [si+14h]
rep movsb
mov bx, di
pop ax
pop di
ret
.nonresident:
; nonresident attribute
cmp dword [di+10h], 0
jnz @b
; read start of data
mov si, di
pop di
call process_mcb_nonres
push di
.notfound1:
; $ATTRIBUTE_LIST is always in base file record
cmp word [esp+2], 20h
jz .nofragmented
; scan for $ATTRIBUTE_LIST = 20h
mov di, [esp+4]
mov ax, 20h
call find_attr
test di, di
jz .nofragmented
; load $ATTRIBUTE_LIST itself
push es
mov bx, 0C000h
mov di, [esp+6]
push bx
push [ofs]
push ds
pop es
call load_attr
pop [ofs]
pop si
mov bx, 8000h
push bx
push si
call read_attr_full
pop si
pop bx
add dx, bx
mov ax, [esp+4]
pop es
.1:
cmp [bx], ax
jnz .continue1
; only unnamed $DATA attributes!
cmp ax, 80h
jnz @f
cmp byte [bx+6], 0
jnz .continue1
@@:
cmp dword [bx+10h], 0
jz .continue1
cmp dword [bx+8], 0
jnz @f
push ax
mov ax, [esp+2]
cmp ax, [ofs]
pop ax
jnz .continue1
@@:
pushad
mov eax, [bx+10h]
mov bx, dx
push [ofs]
push es
push ds
pop es
call read_file_record
pop es
pop [ofs]
popad
pushad
mov di, dx
add di, [di+14h]
.2:
call find_attr.1
mov eax, [bx+8]
cmp eax, [di+10h]
jnz .2
mov si, di
mov di, [esp+20h]
sub di, 4
call process_mcb_nonres
mov [esp+20h], di
popad
.continue1:
add bx, [bx+4]
cmp bx, dx
jb .1
.nofragmented:
pop bx
pop ax
pop di
cmp bx, [ofs]
jnz @f
dec bx
stc
@@:
ret
read_attr_full:
; in: si->decoded attribute data, bx->buffer
; out: edx=length in bytes
lodsb
cmp al, 0
jnz .nonresident
; resident
lodsw
movzx edx, ax
xchg ax, cx
mov di, bx
rep movsb
ret
.nonresident:
; nonresident :-)
xor edx, edx
.loop:
lodsd
xchg ecx, eax
jecxz .loopend
lodsd
xchg edi, eax
; read ecx clusters from cluster edi to es:bx
.intloop:
push ecx
; read 1 cluster from physical cluster edi to es:bx
mov ecx, [cluster_size]
mov eax, edi
mul ecx
push bx
call relative_read
pop bx
pop ecx
inc edi
mov eax, [cluster_size]
add edx, eax
shr eax, 4
mov bp, es
add bp, ax
mov es, bp
loop .intloop
jmp .loop
.loopend:
mov es, cx
ret
read_file_record:
; in: eax=index of record, bx=buffer
mov si, 700h
mov ecx, [frs_size]
mul ecx
push bx
push [cur_obj]
mov [cur_obj], mft_string
call read_attr
pop [cur_obj]
pop di
call restore_usa
ret
read_attr:
; in: edx:eax=offset in bytes, ecx=size in bytes, bx=buffer, si=attribute
push invalid_read_request_string
cmp byte [si], 0
jnz .nonresident
test edx, edx
jnz find_error_sp
cmp eax, 10000h
jae find_error_sp
cmp ecx, 10000h
jae find_error_sp
cmp ax, [si+2]
jae find_error_sp
cmp cx, [si+2]
ja find_error_sp
add si, 3
add si, ax
mov di, bx
rep movsb
pop ax
ret
.nonresident:
mov edi, [cluster_size]
div edi
mov [ofs], dx
add cx, dx
push eax
xchg eax, ecx
xor edx, edx
dec eax
div edi
inc eax
xchg eax, ecx
pop eax
add si, 1
xor edx, edx
push bx
; eax=offset in clusters, ecx=size in clusters
.scan:
mov ebx, [si]
test ebx, ebx
jz .notfound
add edx, ebx
add si, 8
cmp eax, edx
jae .scan
mov edi, [si-4]
; now edx=end of block, ebx=length of block, edi=start of block on disk
; eax=required offset, ecx=required length
push edx
push edi
sub edx, eax
add edi, ebx
sub edi, edx
cmp edx, ecx
jb @f
mov edx, ecx
@@:
; read (edx) clusters from (edi=disk offset in clusters) to ([esp+8])
cmp [ofs], 0
jnz .ofs_read
.cont:
pushad
movzx ebx, byte [50Dh]
; xchg eax, edx
; mul ebx
xchg ax, dx
mul bx
xchg cx, ax
xchg eax, edi
mul ebx
mov bx, [esp+8+20h]
call relative_read
mov [esp+8+20h], bx
popad
.cont2:
add eax, edx
sub ecx, edx
.cont3:
pop edi
pop edx
jnz .scan
pop bx
pop ax
ret
.ofs_read:
push ecx
movzx ecx, byte [50Dh] ; bpb_sects_per_clust
mov eax, edi
push edx
mul ecx
push 1000h
pop es
xor bx, bx
call relative_read
mov cx, bx
push si
push di
mov si, [ofs]
mov di, [esp+8+12]
sub cx, si
push ds
push es
pop ds
pop es
rep movsb
mov [esp+8+12], di
push es
pop ds
pop di
pop si
pop edx
pop ecx
inc edi
mov [ofs], 0
inc eax
dec ecx
jz .cont3
dec edx
jnz .cont
jmp .cont2
.notfound:
mov si, invalid_read_request_string
jmp find_error_si
ntfs_parse_dir:
; in: eax=directory iRecord, [word sp+2]=filename
; out: si=$DATA attribute of file
mov bx, [free]
mov [dir], bx
push bx
call read_file_record
mov ax, word [frs_size]
add [free], ax
pop di
; find attributes $INDEX_ROOT, $INDEX_ALLOCATION, $BITMAP
mov ax, 90h ; $INDEX_ROOT
push di
mov bx, [free]
mov [index_root], bx
call load_attr
mov si, noindex_string
jc find_error_si
mov [free], bx
pop di
mov ax, 0A0h ; $INDEX_ALLOCATION
mov bx, [free]
mov [index_alloc], bx
call load_attr
jnc @f
mov [index_alloc], 0
@@:
mov [free], bx
; search for entry
mov si, [index_root]
mov bx, [free]
call read_attr_full
mov ebp, [bx+8] ; subnode_size
add bx, 10h
.scan_record:
add bx, [bx]
.scan:
test byte [bx+0Ch], 2
jnz .not_found
mov si, [esp+2]
movzx cx, byte [bx+50h] ; namelen
lea di, [bx+52h] ; name
xor ax, ax
@@:
lodsb
cmp al, 'a'
jb .notletter
cmp al, 'z'
ja .notletter
or byte [di], 20h
.notletter:
scasw
loopz @b
jb .not_found
ja @f
cmp byte [esi], 0
jz .file_found
@@:
add bx, [bx+8]
jmp .scan
.not_found:
test byte [bx+0Ch], 1
jz file_not_found
cmp [index_alloc], 0
jz file_not_found
add bx, [bx+8]
mov eax, [bx-8]
mul [cluster_size]
mov si, [index_alloc]
mov ecx, ebp
mov bx, [free]
call read_attr
mov di, [free]
call restore_usa
mov bx, [free]
add bx, 18h
jmp .scan_record
.file_found:
mov si, [esp+2]
mov [cur_obj], si
cmp byte [esp+4], 0
jz .need_file
mov si, notdir_string
test byte [bx+48h+3], 10h
jz find_error_si
mov eax, [bx]
mov bx, [dir]
mov [free], bx
ret 2
.need_file:
mov si, directory_string
test byte [bx+48h+3], 10h ; directory?
jnz find_error_si
; read entry
mov eax, [bx]
mov bx, [dir]
mov [free], bx
mov bx, 4000h
push bx
call read_file_record
pop di
mov ax, 80h
push 2000h
pop es
xor bx, bx
call load_attr
mov si, nodata_string
jz find_error_si
mov [free], bx
ret 2