;Copyright (C) 1999-2000 Konstantin Boldyshev ; ;$Id: fcd.asm,v 0.1 (C) 2001 Paul Hayter ; ; FCD ; ; Hacked up asmutils tool. Finds the first CDROM and then creates a link to ; it in the current directory ; %include "system.inc" CODESEG mediastr db '/proc/ide/ide0/hda/media',0 helperstr db '0a0b1c1d',0 lf db 0x0a dev db '/dev',0 cdrom db 'cdrom',0 proc_dev db 'none',0 proc_mpt db '/proc',0 proc_fs db 'proc',0 devcd db '/dev/cdrom',0 cdmpt db '/cdrom',0 iso db 'iso9660',0 ext2 db 'ext2',0 blank db 0 src_file db '/cdrom/rootfs',0 src_file2 db '/cdrom/rootfs.lz',0 dest_file db '/dev/ram1',0 ram_mnt db '/ram',0 ram_dev db '/ram/dev',0 slash db '/',0 loading1 db 'Loading rootfs ...',0x0a,0 loading2 db 'Loading rootfs.lz .....',0x0a,0 ;decomp stuff llstuff equ 8 hl1stuff equ 5 hl2stuff equ 10 hf2stuff equ 33 START: cld _mov esi,mediastr _mov edi,mediabuf call cp_string call mount_proc ; Try to open /proc/ide/ide0/hda/media, then /proc/ide/ide0/hdb/media ... ; Assume that the first one that says 'cdrom' is our boot CD _mov esi,helperstr cld .l2: lodsb or al,al je near .l1 mov [edi + 13],al lodsb mov [edi + 17],al sys_open edi,O_RDONLY mov ebp,eax test eax,eax js .l2 ;We've got the file open. Read it to see if it says 'cdrom' _mov ebx, Buf mov long [ ebx ] , 0 sys_read ebp,ebx,BufSize push eax sys_close ebp pop eax test eax,eax js near .l2 ; We've read something from it _mov ebx,Buf cmp long [ ebx ], "cdro" je near .found_cd jmp near .l2 .l1: sys_exit 0 ; At this point our mediabuf should have the right name in it, which is ; enough for us to make a symlink .found_cd: sys_chdir dev mov esi, mediabuf + 15 mov byte [ esi + 3 ], 0 ; create the /dev/cdrom ->hdx symlink sys_symlink esi,cdrom mov ebp,esi ; mount the cdrom call mount_cdrom call dd_filesystem call mount_ram sys_chdir ram_dev sys_symlink mediabuf + 15,cdrom sys_chdir slash sys_umount ram_mnt sys_umount cdmpt sys_umount proc_mpt sys_exit 0 dd_filesystem: sys_open src_file,O_RDONLY test eax,eax jns .no_error sys_open src_file2, O_RDONLY test eax,eax jns dd_compressed_fs _mov eax,1 ret .no_error: push eax mov esi,loading1 call prt_string pop eax mov esi,eax sys_open dest_file,O_WRONLY|O_CREAT|O_TRUNC test eax,eax jns .no_error2 sys_close esi _mov eax,2 ret .no_error2: mov edi, eax .l1: sys_read esi,dd_buf,dd_buf_size test eax,eax jz .no_more_data js .read_err mov edx,eax sys_write edi,dd_buf,edx jmp .l1 .read_err: sys_close edi sys_close esi _mov eax,3 ret .no_more_data: sys_close edi sys_close esi _mov eax,0 ret dd_compressed_fs: ; eax should be set to the rootfs.lz filehandle push eax mov esi,loading2 call prt_string pop eax mov ebp,eax sys_lseek ebp,0, SEEK_END push eax ; eax = lenght of compressed file sys_lseek ebp,0, SEEK_SET pop eax mov [ data_length ], eax mov esi,dcBuf add esi,dcBufSize sub esi, eax mov ecx, eax sys_read ebp,esi,ecx test eax,eax jns .read_ok sys_close ebp mov eax,3 ret .read_ok: sys_close ebp lodsd ; load the first 4 bytes containing the real length mov [ actual_size ] , eax mov [ lz_start ], esi call decompress mov edi , [ actual_size ] sys_open dest_file, O_WRONLY|O_CREAT|O_TRUNC test eax,eax jns .wr_open_ok mov eax,5 ret .wr_open_ok: mov ebp,eax sys_write ebp,dcBuf,edi sys_close ebp xor eax,eax ret decompress: xor ebp,ebp xor ecx,ecx xor eax,eax xor ebx,ebx mov edi,dcBuf ; Destination offset ;push edi ; Push edi for the final ret pusha mov eax,esi add eax, [ data_length ] mov [ end_point ] , eax ; Main loop ----------------------------------------------------------------- main_loop: eoff: cmp esi,[end_point] ; EOF? jb noquit mov [ dest_end ] , edi popa xor edi, edi ret noquit: call get_bit ; Compressed/uncompressed data next? jc compressed ; Handle uncompressed data -------------------------------------------------- mov cl,8 ; Uncompressed -> Get next 8 bits cdq ; No fix-ups (clear edx) call get_data ; Get byte xchg eax,ebx ; Store the byte stosb ;jmp is 5 bytes long, clc jnc is only 3, we win 2 bytes ! ;jmp main_loop ; Loop clc jnc main_loop ; Handle compressed data ---------------------------------------------------- compressed: ll: mov dl,llstuff ; Maximum number of bits in a row bit_loop: call get_bit ; Loop until CF = 0 jnc c_getpos inc ecx ; Increase lenght dec edx ; Max number of bits read? jnz bit_loop ; Nope -> Keep reading call get_huffman ; Yepp -> Get huffman-coded lenght mov ecx,ebx ; Lenght must be in cx c_getpos: jecxz lenght_1 ; Lenght 1? -> Do something else.... push ecx ; Save lengt call get_huffman ; Get huffman-coded position pop ecx ; Restore lenght c_copy: push esi ; Save old source mov esi,edi ; Calculate new source offset sub esi,ebx inc ecx ; Fix lenght rep movsb ; Copy duplicate data pop esi ; Restore source offset ;jmp main_loop ; Loop clc jnc main_loop lenght_1: mov cl,4 ; Get 4 bits of data for position cdq ; Fix-up value inc edx ; (dx = 1) call get_data ; Get data ;jmp c_copy ; Go back to loop clc jnc c_copy ; Get one bit of data ------------------------------------------------------- ; Returns: ; CF - Value of the bit gb_next_byte: xor eax,eax ; Very Important lodsb ; Get one byte mov ah,1 ; Mark the end of data xchg ebp,eax ; Move it to bp get_bit: shr ebp,1 ; Get bit to CF jz gb_next_byte ; No more bits left in dx? ret ; Get huffman-coded number -------------------------------------------------- ; Returns: ; bx - The number get_huffman: mov cx,hl1stuff ; Assume 3 bits for the number cdq ; Fix-up value inc edx ; (dx = 1) call get_bit ; Get huffman bit jnc get_data ; Was 0 -> Values were correct mov cl,hl2stuff ; Was 1 -> 5 bits for the number mov dl,hf2stuff ; Fix-up value ; Get n bits of data -------------------------------------------------------- ; Input: ; cx - Number of bits wanted ; dx - Fix-up value to be added to the result ; Returns: ; bx - The requested number get_data: xor ebx,ebx gd_loop: call get_bit ; Get bit rcl ebx,1 ; Store it loop gd_loop ; Loop add ebx,edx ; Fix the value ret mount_ram: sys_mount dest_file,ram_mnt,ext2,0xc0ed0000,blank ret mount_cdrom: sys_mount devcd,cdmpt,iso,0xc0ed0001,blank ret mount_proc: mov ebx, proc_dev mov ecx, proc_mpt mov edx, proc_fs mov esi,0 sys_mount ret ; esi points to zero terminated string ; edi is the destination cp_string: push esi push edi cld .cp_next: lodsb or al,al je .null_end stosb jmp near .cp_next .null_end: stosb pop edi pop esi ret ; esi points to a zero ended string to print prt_string: pushad push esi _mov ecx,0 jmp near .l2 .l1: inc esi inc ecx .l2: cmp [esi],byte 0 jnz .l1 pop esi sys_write STDOUT,esi,ecx sys_write STDOUT,lf,1 popad ret UDATASEG BufSize equ 128 Buf resb BufSize dd_buf_size equ 1024 dd_buf resb dd_buf_size mediabuf resb 40 ; decompression stuff dcBufSize equ 4194304+8192 dcBuf resb dcBufSize end_point resb 4 decompress_to resb 4 dest_end resb 4 data_length resb 4 actual_size resb 4 lz_start resb 4 END