; **************************************************************************** ; mount8086.s (mount0.s) - by Erdogan Tan - 08/05/2022 ; ---------------------------------------------------------------------------- ; Retro UNIX 8086 v1 - mount -- mount file system ; ; [ Last Modification: 10/05/2022 ] ; ; **************************************************************************** ; (/etc/mount) ; mount0.s - Retro UNIX 8086 v1 (16 bit version of 'mount1.s') ; mount1.s - Retro UNIX 386 v1 (& v1.1 & v1.2) ; UNIX v1 system calls _rele equ 0 _exit equ 1 _fork equ 2 _read equ 3 _write equ 4 _open equ 5 _close equ 6 _wait equ 7 _creat equ 8 _link equ 9 _unlink equ 10 _exec equ 11 _chdir equ 12 _time equ 13 _mkdir equ 14 _chmod equ 15 _chown equ 16 _break equ 17 _stat equ 18 _seek equ 19 _tell equ 20 _mount equ 21 _umount equ 22 _setuid equ 23 _getuid equ 24 _stime equ 25 _quit equ 26 _intr equ 27 _fstat equ 28 _emt equ 29 _mdate equ 30 _stty equ 31 _gtty equ 32 _ilgins equ 33 _sleep equ 34 ; Retro UNIX 8086 v1 feature only ! _msg equ 35 ; Retro UNIX 386 v1 feature only ! _geterr equ 36 ; Retro UNIX 386 v1 feature only ! ;;; ESCKey equ 1Bh EnterKey equ 0Dh ;%macro sys 1-4 ; ; 03/09/2015 ; ; 13/04/2015 ; ; Retro UNIX 386 v1 system call. ; %if %0 >= 2 ; mov ebx, %2 ; %if %0 >= 3 ; mov ecx, %3 ; ;%if %0 = 4 ; %if %0 >= 4 ; 11/03/2022 ; mov edx, %4 ; %endif ; %endif ; %endif ; mov eax, %1 ; int 30h ;%endmacro %macro sys 1-4 ; Retro UNIX 8086 v1 system call. %if %0 >= 2 mov bx, %2 %if %0 >= 3 mov cx, %3 %if %0 >= 4 mov dx, %4 %endif %endif %endif mov ax, %1 int 20h %endmacro ;; Retro UNIX 386 v1 system call format: ;; sys systemcall (eax) , , ;; 11/03/2022 ;; Note: Above 'sys' macro has limitation about register positions; ;; ebx, ecx, edx registers must not be used after their ;; positions in sys macro. ;; for example: ;; 'sys _write, 1, msg, ecx' is defective, because ;; ecx will be used/assigned before edx in 'sys' macro. ;; correct order may be: ;; 'sys _write, 1, msg, eax ; (eax = byte count) ; Retro UNIX 8086 v1 system call format: ; sys systemcall (ax) , , ; ---------------------------------------------------------------------------- [BITS 16] ; 16-bit intructions (8086/8088 - Real Mode) [ORG 0] START_CODE: ; 10/05/2022 ; 09/05/2022 (16 bit code) ; 08/05/2022 pop cx ; cx = number of arguments ; pop ax ; ax = argument 0 = executable file name ; ;cmp cx, 3 cmp cl, 3 jne short mnt_0 pop di ; argument 1 = device name pop bp ; argument 2 = mounting directory mov si, bp ; 09/05/2022 ;; 'pwd' command compatibility restriction ! ;; ; --- ;; ; Only '/usr' or '/mnt' directories can be used ;; ; with current mount version (otherwise current ;; ; 'pwd' will not recognize mounting directory ;; ; as correct). ; ; ; short way... ; ; lodsw ; cmp al, '/' ; jne short mnt_5 ; cmp ah, 'u' ; jne short mnt_m ;mnt_u: ; lodsw ; cmp ax, 'sr' ; je short mnt_1 ; jmp short mnt_2 ;mnt_m: ; cmp ah, 'm' ; jne short mnt_2 ; lodsw ; cmp ax, 'nt' ; jne short mnt_2 ;mnt_1: ; cmp byte [si], 0 ; ; jna short mnt_5 ; '/usr' or '/mnt', continue ; ; ; neither '/usr' or '/mnt' ; ; print usage message and then exit ;mnt_0: ; mov ax, usage_msg ; jmp short mnt_7 ;p_msg_exit: ; call print_msg ;exit: ; sys _exit ;hang: ; nop ; jmp short hang mnt_2: ; long way... sys _stat, bp, stbuf jc short mnt_dir_err ; ax = device number ; is directory ? (check inode mode) test byte [stbuf+3], 40h ; directory jz short mnt_dir_err ; is already mounted ? or ax, ax jnz short mnt_dir_err ; mov dx, [stbuf] ; inode number ; ; sys _stat, usr, stbuf ; jc short mnt_4 ; ; ; check if it is '/usr' inode ; cmp dx, [stbuf] ; same inode number ; je short mnt_5 ;mnt_4: ; sys _stat, mnt, stbuf ; jc short mnt_dir_err ; ; ; check if it is '/mnt' inode ; cmp dx, [stbuf] ; same inode number ; jne short mnt_dir_err mnt_5: ; only superuser (root) can do mount/umount sys _getuid and ax, ax ; uid = 0 -> root jz short mnt_6 mov ax, deny_msg jmp short mnt_7 ; 10/05/2022 ; print usage message and then exit mnt_0: mov ax, usage_msg mnt_7: call print_msg exit: sys _exit ;hang: ; nop ; jmp short hang mnt_6: ; di = device name address ; bp = mounting directory path/name address ; ; 09/05/2022 ; Note: Retro UNIX 8086 v1 kernel ; (and original unix v1 kernel, sysmount) ; mounts devices without checking superblock ; validity. So, sysmount does not return ; with 'invalid file system' error. ; (but Retro UNIX 386 sysmount returns with ; 'invalid file system' error) ; ; At sysmount system call return, ; if cf=1 it is user permission error ; or disk r/w error or 'already mounted' error. sys _mount, di, bp jc short mnt_err ; mov ax, ok_msg ; 10/05/2022 jmp short mnt_7 ;mnt_7: ; call print_msg ;exit: ; sys _exit ;;hang: ;; nop ;; jmp short hang mnt_dir_err: mov ax, dir_err_msg jmp short mnt_7 mnt_err: ; 09/05/2022 mov ax, err_msg jmp short mnt_7 ;----------------------------------------------------------------- print_msg: ; ax = asciiz string address mov si, ax dec si nextchr: inc si cmp byte [si], 0 ja short nextchr ;cmp [si], 0Dh ;ja short nextchr sub si, ax ; si = asciiz string length ; sys _write, 1, ax, si ; retn ;----------------------------------------------------------------- ; data - initialized data ;----------------------------------------------------------------- ; default mounting directories (for current retro unix version) ;usr: db '/usr', 0 ;mnt: db '/mnt', 0 usage_msg: db 0Dh, 0Ah ;db "Usage: mount " ;db 0Dh, 0Ah ;db " or mount " db "Usage: mount " ;db 0Dh, 0Ah db 0Dh, 0Ah db "Example: mount /dev/fd1 /usr " db 0Dh, 0Ah, 0 deny_msg: db 0Dh, 0Ah db "Mount: Only superuser/root can mount devices!" db 0Dh, 0Ah, 0 err_msg: db 0Dh, 0Ah db 'Error! ' db 0Dh, 0Ah, 0 dir_err_msg: db 0Dh, 0Ah db 'Mount Directory Error!' ;db 0Dh, 0Ah ;db "(Mounting directory must exist " ;db "and be '/usr' or '/mnt'.)", db 0Dh, 0Ah, 0 ok_msg: db 0Dh, 0Ah db 'OK. ' nextline: db 0Dh, 0Ah, 0 ;----------------------------------------------------------------- ; bss - uninitialized data ;----------------------------------------------------------------- align 4 bss_start: ABSOLUTE bss_start ; sysstat buffer stbuf: resb 34 ; (Retro UNIX 8086/386 v1 & Retro UNIX 386 v1.1) ;-----------------------------------------------------------------