me again, file functions

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Dreamz

Joined: 10 Apr 2009
Posts: 25
Location: US

Dreamz 14 May 2009, 15:48

hey, i hav always liked file functions like in php and stuff but in assembly im not exactly getting it or somthing.

just 4 fun im trying to make a program that creates a file and copies a file.
the final thing i'd like it to be able to be told my the user wat to name the file and wat is in it.
but i can hardly create a file, i hav looked down through posts and found some info, but not enough. and hav been looking through the kernel32.inc.
like CreateFile,\
but i just dont get the "syntax" thing, like how to use it, i picked up this code from a post and changed it a bit:

Code:


include 'win32ax.inc'

.code

  start:
          invoke  CreateFile,echo,GENERIC_WRITE,\
          FILE_SHARE_READ,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0

invoke ExitProcess,0

.end start

echo db 'G:\Hey.txt',0

could som1 explain it?
how do you define the contents of the file?
how do you copy a file?

thanks!
sry to bother again

14 May 2009, 15:48

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20448
Location: In your JS exploiting you and your system

revolution 14 May 2009, 15:52

Dreamz wrote:

how do you define the contents of the file?

With WriteFile.

Dreamz wrote:

how do you copy a file?

Erm, with a function named CopyFile.

14 May 2009, 15:52

Dreamz

Joined: 10 Apr 2009
Posts: 25
Location: US

Dreamz 14 May 2009, 15:59

well i mean im almost a complete beginner, could you give an example, like:

Code:



include 'win32ax.inc'

.code

  start:
          invoke  CreateFile,echo,GENERIC_WRITE,\
          FILE_SHARE_READ,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0

invoke ExitProcess,0

.end start

echo db 'G:\Hey.txt',0

Code:

          invoke  CreateFile,echo,GENERIC_WRITE,\
          FILE_SHARE_READ,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0  
...
...
echo db 'G:\Hey.txt',0

that is if its rly big
thanks!

14 May 2009, 15:59

bitshifter

Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA

bitshifter 15 May 2009, 02:14

Open a file, get its size, allocate a buffer and read in the data.
*takes breath*
Close the file, create a new file, write the data, close the file.

For reading a file into a dynamic buffer study my texture loader.
http://board.flatassembler.net/topic.php?t=9885

_________________
Coding a 3D game engine with fasm is like trying to eat an elephant,
you just have to keep focused and take it one 'byte' at a time.

15 May 2009, 02:14

wht36

Joined: 18 Sep 2005
Posts: 106

wht36 16 Jun 2009, 10:29

To copy a file, you need to:
1. open the source file,
2. open the destination file
3. read the contents of source file into a buffer
4. write the contents of the buffer to the destination file

see attached exampled asm

Description:		Download
Filename:	filter.asm
Filesize:	5.62 KB
Downloaded:	163 Time(s)

16 Jun 2009, 10:29

eskizo

Joined: 22 Nov 2005
Posts: 59

eskizo 17 Jun 2009, 16:25

this is the "begginer" example:

Code:

include 'include\win32ax.inc'

.code

start:  invoke CreateFile, fname, GENERIC_WRITE, FILE_SHARE_READ,\
        0, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0

        mov [fhandle], eax

        invoke WriteFile, eax, fname, 10, garbage, 0
        invoke CloseHandle, fhandle

        invoke ExitProcess, 0

.end start

fname db 'HelloWorld.txt',0
fhandle dd 0
garbage dd 0 ;necessary

cya

17 Jun 2009, 16:25

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