assembly - 系统调用所请求文件的 INFO(如果存在)

Question

我正在尝试在MikeOS操作系统中设计和实现系统调用。该调用可通过 MikeOS 中的命令行界面 (CLI) 进行访问。我正在尝试进行系统调用 INFO，它将显示所请求文件(如果存在)的信息(未格式化)。显示的信息包括

• 属性字节。
• 创建时间。
• 创建日期
• 上次访问日期
• 上次写入时间
• 文件大小(以字节为单位)

我应该在其中添加 INFO 的系统调用。我不知道该怎么做或从哪里开始。我在 SERIAL 中添加了但找不到任何调用 INFO 的好例子或如何这样做

源代码

; ==================================================================
; MikeOS -- The Mike Operating System kernel
; Copyright (C) 2006 - 2014 MikeOS Developers -- see doc/LICENSE.TXT
;
; COMMAND LINE INTERFACE
; ==================================================================




os_command_line:
    call os_clear_screen


    mov si, version_msg
    call os_print_string
    mov si, help_text
    call os_print_string




get_cmd:                ; Main processing loop
    mov di, input           ; Clear input buffer each time
    mov al, 0
    mov cx, 256
    rep stosb


    mov di, command         ; And single command buffer
    mov cx, 32
    rep stosb


    mov si, prompt          ; Main loop; prompt for input
    call os_print_string


    mov ax, input           ; Get command string from user
    call os_input_string


    call os_print_newline


    mov ax, input           ; Remove trailing spaces
    call os_string_chomp


    mov si, input           ; If just enter pressed, prompt again
    cmp byte [si], 0
    je get_cmd


    mov si, input           ; Separate out the individual command
    mov al, ' '
    call os_string_tokenize


    mov word [param_list], di   ; Store location of full parameters


    mov si, input           ; Store copy of command for later modifications
    mov di, command
    call os_string_copy






    ; First, let's check to see if it's an internal command...


    mov ax, input
    call os_string_uppercase


    mov si, input


    mov di, exit_string     ; 'EXIT' entered?
    call os_string_compare
    jc near exit


    mov di, help_string     ; 'HELP' entered?
    call os_string_compare
    jc near print_help


    mov di, cls_string      ; 'CLS' entered?
    call os_string_compare
    jc near clear_screen


    mov di, dir_string      ; 'DIR' entered?
    call os_string_compare
    jc near list_directory


    mov di, ver_string      ; 'VER' entered?
    call os_string_compare
    jc near print_ver


    mov di, time_string     ; 'TIME' entered?
    call os_string_compare
    jc near print_time


    mov di, date_string     ; 'DATE' entered?
    call os_string_compare
    jc near print_date


    mov di, cat_string      ; 'CAT' entered?
    call os_string_compare
    jc near cat_file


    mov di, del_string      ; 'DEL' entered?
    call os_string_compare
    jc near del_file


    mov di, copy_string     ; 'COPY' entered?
    call os_string_compare
    jc near copy_file


    mov di, ren_string      ; 'REN' entered?
    call os_string_compare
    jc near ren_file


    mov di, size_string     ; 'SIZE' entered?
    call os_string_compare
    jc near size_file


    mov di, serial_string       ; 'SERIAL' entered?
    call os_string_compare
    jc near serial_file




    ; If the user hasn't entered any of the above commands, then we
    ; need to check for an executable file -- .BIN or .BAS, and the
    ; user may not have provided the extension


    mov ax, command
    call os_string_uppercase
    call os_string_length




    ; If the user has entered, say, MEGACOOL.BIN, we want to find that .BIN
    ; bit, so we get the length of the command, go four characters back to
    ; the full stop, and start searching from there


    mov si, command
    add si, ax


    sub si, 4


    mov di, bin_extension       ; Is there a .BIN extension?
    call os_string_compare
    jc bin_file


    mov di, bas_extension       ; Or is there a .BAS extension?
    call os_string_compare
    jc bas_file


    jmp no_extension




bin_file:
    mov ax, command
    mov bx, 0
    mov cx, 32768
    call os_load_file
    jc total_fail


execute_bin:
    mov si, command
    mov di, kern_file_string
    mov cx, 6
    call os_string_strincmp
    jc no_kernel_allowed


    mov ax, 0           ; Clear all registers
    mov bx, 0
    mov cx, 0
    mov dx, 0
    mov word si, [param_list]
    mov di, 0


    call 32768          ; Call the external program


    jmp get_cmd         ; When program has finished, start again






bas_file:
    mov ax, command
    mov bx, 0
    mov cx, 32768
    call os_load_file
    jc total_fail


    mov ax, 32768
    mov word si, [param_list]
    call os_run_basic


    jmp get_cmd






no_extension:
    mov ax, command
    call os_string_length


    mov si, command
    add si, ax


    mov byte [si], '.'
    mov byte [si+1], 'B'
    mov byte [si+2], 'I'
    mov byte [si+3], 'N'
    mov byte [si+4], 0


    mov ax, command
    mov bx, 0
    mov cx, 32768
    call os_load_file
    jc try_bas_ext


    jmp execute_bin




try_bas_ext:
    mov ax, command
    call os_string_length


    mov si, command
    add si, ax
    sub si, 4


    mov byte [si], '.'
    mov byte [si+1], 'B'
    mov byte [si+2], 'A'
    mov byte [si+3], 'S'
    mov byte [si+4], 0


    jmp bas_file






total_fail:
    mov si, invalid_msg
    call os_print_string


    jmp get_cmd




no_kernel_allowed:
    mov si, kern_warn_msg
    call os_print_string


    jmp get_cmd




; ------------------------------------------------------------------


print_help:
    mov si, help_text
    call os_print_string
    jmp get_cmd




; ------------------------------------------------------------------


clear_screen:
    call os_clear_screen
    jmp get_cmd




; ------------------------------------------------------------------


print_time:
    mov bx, tmp_string
    call os_get_time_string
    mov si, bx
    call os_print_string
    call os_print_newline
    jmp get_cmd




; ------------------------------------------------------------------


print_date:
    mov bx, tmp_string
    call os_get_date_string
    mov si, bx
    call os_print_string
    call os_print_newline
    jmp get_cmd




; ------------------------------------------------------------------


print_ver:
    mov si, version_msg
    call os_print_string
    jmp get_cmd




; ------------------------------------------------------------------


kern_warning:
    mov si, kern_warn_msg
    call os_print_string
    jmp get_cmd




; ------------------------------------------------------------------


list_directory:
    mov cx, 0           ; Counter


    mov ax, dirlist         ; Get list of files on disk
    call os_get_file_list


    mov si, dirlist
    mov ah, 0Eh         ; BIOS teletype function


.repeat:
    lodsb               ; Start printing filenames
    cmp al, 0           ; Quit if end of string
    je .done


    cmp al, ','         ; If comma in list string, don't print it
    jne .nonewline
    pusha
    call os_print_newline       ; But print a newline instead
    popa
    jmp .repeat


.nonewline:
    int 10h
    jmp .repeat


.done:
    call os_print_newline
    jmp get_cmd




; ------------------------------------------------------------------


cat_file:
    mov word si, [param_list]
    call os_string_parse
    cmp ax, 0           ; Was a filename provided?
    jne .filename_provided


    mov si, nofilename_msg      ; If not, show error message
    call os_print_string
    jmp get_cmd


.filename_provided:
    call os_file_exists     ; Check if file exists
    jc .not_found


    mov cx, 32768           ; Load file into second 32K
    call os_load_file


    mov word [file_size], bx


    cmp bx, 0           ; Nothing in the file?
    je get_cmd


    mov si, 32768
    mov ah, 0Eh         ; int 10h teletype function
.loop:
    lodsb               ; Get byte from loaded file


    cmp al, 0Ah         ; Move to start of line if we get a newline char
    jne .not_newline


    call os_get_cursor_pos
    mov dl, 0
    call os_move_cursor


.not_newline:
    int 10h             ; Display it
    dec bx              ; Count down file size
    cmp bx, 0           ; End of file?
    jne .loop


    jmp get_cmd


.not_found:
    mov si, notfound_msg
    call os_print_string
    jmp get_cmd




; ------------------------------------------------------------------


del_file:
    mov word si, [param_list]
    call os_string_parse
    cmp ax, 0           ; Was a filename provided?
    jne .filename_provided


    mov si, nofilename_msg      ; If not, show error message
    call os_print_string
    jmp get_cmd


.filename_provided:
    call os_remove_file
    jc .failure


    mov si, .success_msg
    call os_print_string
    mov si, ax
    call os_print_string
    call os_print_newline
    jmp get_cmd


.failure:
    mov si, .failure_msg
    call os_print_string
    jmp get_cmd




    .success_msg    db 'Deleted file: ', 0
    .failure_msg    db 'Could not delete file - does not exist or write protected', 13, 10, 0




; ------------------------------------------------------------------


size_file:
    mov word si, [param_list]
    call os_string_parse
    cmp ax, 0           ; Was a filename provided?
    jne .filename_provided


    mov si, nofilename_msg      ; If not, show error message
    call os_print_string
    jmp get_cmd


.filename_provided:
    call os_get_file_size
    jc .failure


    mov si, .size_msg
    call os_print_string


    mov ax, bx
    call os_int_to_string
    mov si, ax
    call os_print_string
    call os_print_newline
    jmp get_cmd




.failure:
    mov si, notfound_msg
    call os_print_string
    jmp get_cmd




    .size_msg   db 'Size (in bytes) is: ', 0




; ------------------------------------------------------------------


copy_file:
    mov word si, [param_list]
    call os_string_parse
    mov word [.tmp], bx


    cmp bx, 0           ; Were two filenames provided?
    jne .filename_provided


    mov si, nofilename_msg      ; If not, show error message
    call os_print_string
    jmp get_cmd


.filename_provided:
    mov dx, ax          ; Store first filename temporarily
    mov ax, bx
    call os_file_exists
    jnc .already_exists


    mov ax, dx
    mov cx, 32768
    call os_load_file
    jc .load_fail


    mov cx, bx
    mov bx, 32768
    mov word ax, [.tmp]
    call os_write_file
    jc .write_fail


    mov si, .success_msg
    call os_print_string
    jmp get_cmd


.load_fail:
    mov si, notfound_msg
    call os_print_string
    jmp get_cmd


.write_fail:
    mov si, writefail_msg
    call os_print_string
    jmp get_cmd


.already_exists:
    mov si, exists_msg
    call os_print_string
    jmp get_cmd




    .tmp        dw 0
    .success_msg    db 'File copied successfully', 13, 10, 0




; ------------------------------------------------------------------


ren_file:
    mov word si, [param_list]
    call os_string_parse


    cmp bx, 0           ; Were two filenames provided?
    jne .filename_provided


    mov si, nofilename_msg      ; If not, show error message
    call os_print_string
    jmp get_cmd


.filename_provided:
    mov cx, ax          ; Store first filename temporarily
    mov ax, bx          ; Get destination
    call os_file_exists     ; Check to see if it exists
    jnc .already_exists


    mov ax, cx          ; Get first filename back
    call os_rename_file
    jc .failure


    mov si, .success_msg
    call os_print_string
    jmp get_cmd


.already_exists:
    mov si, exists_msg
    call os_print_string
    jmp get_cmd


.failure:
    mov si, .failure_msg
    call os_print_string
    jmp get_cmd




    .success_msg    db 'File renamed successfully', 13, 10, 0
    .failure_msg    db 'Operation failed - file not found or invalid filename', 13, 10, 0


; ------------------------------------------------------------------


serial_file: 


    mov ah, 2           ; Read disc sectors funtion 
    mov al, 1           ; numbers of sectors to read
    mov ch, 0           ; track/cylinder number 
    mov cl, 1           ; sector number 
    mov dh, 0           ; head number
    mov dl, 0           ; drive number (0=A, 80h = driv 0, 81h = drive 1)
    mov bx, disk_buffer     ; pointer to buffer
    int 13h             ; execute function; AH = status, AL = # of sectors read
    jc .serial_error        ; CF = 0 if successful; 1 is error


    mov si, .serial_msg
    call os_print_string


    mov ax, [disk_buffer + 29h] ; print the first 2 bytes of the serial number 
    call os_print_4hex


    mov si, .separator
    call os_print_string


    mov ax, [disk_buffer + 27h] ; print the second 2 bytes of serial number
    call os_print_4hex  


    call os_print_newline


    jmp .end


.serial_error:


    mov si, .error_msg
    call os_print_string


.end:
    jmp get_cmd


    .separator  db '_', 0
    .serial_msg db 'The serial number is: ', 0
    .error_msg  db 'Error reading disk.', 13, 10, 0
    .disk_buffer    times 512 db 0 






; ------------------------------------------------------------------


exit:
    ret




; ------------------------------------------------------------------


    input           times 256 db 0
    command         times 32 db 0


    dirlist         times 1024 db 0
    tmp_string      times 15 db 0


    file_size       dw 0
    param_list      dw 0


    bin_extension       db '.BIN', 0
    bas_extension       db '.BAS', 0


    prompt          db '> ', 0


    help_text       db 'Commands: DIR, COPY, REN, DEL, CAT, SIZE, CLS, HELP, TIME, DATE, VER, EXIT, SERIAL', 13, 10, 0
    invalid_msg     db 'No such command or program', 13, 10, 0
    nofilename_msg      db 'No filename or not enough filenames', 13, 10, 0
    notfound_msg        db 'File not found', 13, 10, 0
    writefail_msg       db 'Could not write file. Write protected or invalid filename?', 13, 10, 0
    exists_msg      db 'Target file already exists!', 13, 10, 0


    version_msg     db 'MikeOS ', MIKEOS_VER, 13, 10, 0


    exit_string     db 'EXIT', 0
    help_string     db 'HELP', 0
    cls_string      db 'CLS', 0
    dir_string      db 'DIR', 0
    time_string     db 'TIME', 0
    date_string     db 'DATE', 0
    ver_string      db 'VER', 0
    cat_string      db 'CAT', 0
    del_string      db 'DEL', 0
    ren_string      db 'REN', 0
    copy_string     db 'COPY', 0
    size_string     db 'SIZE', 0
    serial_string       db 'SERIAL', 0  
    kern_file_string    db 'KERNEL', 0
    kern_warn_msg       db 'Cannot execute kernel file!', 13, 10, 0




; ==================================================================

Answer 1

您可以通过查看 Mike 如何执行 os_get_file_size API 调用来轻松完成此任务。
对于您的任务，您不仅返回 BX 中的文件大小，还返回您选择的任何其他寄存器中的其他信息。
这可能是这样的选择:

AL = Attribute byte.
CX = Creation Time.
DX = Creation Date
SI = Last Access Date
DI = Last Write Time
BX = File size in bytes

<小时/>

; --------------------------------------------------------------------------
; os_get_file_size -- Get file size information for specified file
; IN: AX = filename; OUT: BX = file size in bytes (up to 64K)
; or carry set if file not found

os_get_file_size:
    pusha
    call os_string_uppercase
    call int_filename_convert
    clc
    push ax
    call disk_read_root_dir
    jc .failure
    pop ax
    mov di, disk_buffer
    call disk_get_root_entry
    jc .failure
    mov word bx, [di+28]        <<<<< FileSize
    mov word [.tmp], bx
    popa
    mov word bx, [.tmp]
    ret
.failure:
    popa
    stc
    ret
.tmp    dw 0

<小时/>

这是存储所有这些信息的地方。现在您知道 Mike 是从哪里得到 mov 单词 bx, [di+28] 的。

byte [di+11], 0     ; Attributes             AL
byte [di+12], 0     ; Reserved
byte [di+13], 0     ; Reserved
byte [di+14], 0C6h  ; Creation time         \CX
byte [di+15], 07Eh  ; Creation time         /
byte [di+16], 0     ; Creation date         \DX
byte [di+17], 0     ; Creation date         /
byte [di+18], 0     ; Last access date      \SI
byte [di+19], 0     ; Last access date      /
byte [di+20], 0     ; Ignore in FAT12
byte [di+21], 0     ; Ignore in FAT12
byte [di+22], 0C6h  ; Last write time       \DI
byte [di+23], 07Eh  ; Last write time       /
byte [di+24], 0     ; Last write date
byte [di+25], 0     ; Last write date
byte [di+26], 0     ; First logical cluster
byte [di+27], 0     ; First logical cluster
byte [di+28], 0     ; File size              \BX
byte [di+29], 0     ; File size              /
byte [di+30], 0     ; File size
byte [di+31], 0     ; File size

<小时/>

如果您想从命令行显示所有这些信息，那么就像您编写的 SERIAL 命令一样，您必须将返回的寄存器中的数字转换为文本，小菜一碟!

此外，如果您将代码添加到DISK.ASM并更新KERNEL.ASM<中的os_call_vectors表，您的代码可以成为API的扩展/em>.

通过查看执行与您想要执行的操作类似的操作的现有代码，您可以学到很多东西