Problema creating DLL with FASM (newbie in fasm)

Index > Windows > Problema creating DLL with FASM (newbie in fasm)

Author

Thread

Fungos Bauux

Joined: 19 Jan 2005
Posts: 31
Location: CWB

Fungos Bauux 12 Jan 2006, 02:00

Im trying to create a DLL that will talk with JAVA RMI, but windows says that my dlls is invalid.

DLL:

Code:

format pe dll
entry start

include 'win32a.inc'

section '.code' code readable executable

proc start hinstDLL, fdwReason, lpvReserved
        mov     eax, TRUE
        ret
endp

; void readString(char *);
proc readString pStr
        ret
endp

section '.edata' export data readable

  export 'MY.DLL',\
         readString,'readString'

section '.reloc' fixups data discardable

my test loader is this:

Code:

format pe console
entry start

include 'win32a.inc'

section '.code' code readable executable

  start:
        invoke  readString, myString
        invoke  ExitProcess, 0

section '.data' data readable writeable

  myString      db      'Some string',0

section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          mydll,'MY.DLL'

  import kernel,\
         ExitProcess,'ExitProcess'

  import mydll,\
         readString,'readString'

what im doing wrong?

12 Jan 2006, 02:00

RedGhost

Joined: 18 May 2005
Posts: 443
Location: BC, Canada

RedGhost 12 Jan 2006, 03:45

hey i created a test dll/program with your code

dll

Code:

format pe dll
entry start

include '%fasminc%\win32a.inc'

section '.code' code readable executable

proc start hinstDLL, fdwReason, lpvReserved
        mov     eax, TRUE
        ret
endp

; void readString(char *);
proc readString pStr
        invoke MessageBoxA, 0, [pStr], 0, 0
        ret
endp

section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          user, 'USER32.DLL'

  import kernel,\
         ExitProcess,'ExitProcess'

  import user,\
         MessageBoxA,'MessageBoxA'


section '.edata' export data readable

  export 'MY.DLL',\
         readString,'readString'

section '.reloc' fixups data discardable

exe

Code:

format pe gui
entry start

include '%fasminc%\win32a.inc'

section '.code' code readable executable

  start:
        invoke  readString, myString
        invoke  ExitProcess, 0

section '.data' data readable writeable

  myString      db      'Some string',0

section '.idata' import data readable writeable

  library kernel,'KERNEL32.DLL',\
          mydll,'MY.DLL'

  import kernel,\
         ExitProcess,'ExitProcess'

  import mydll,\
         readString,'readString'

i also tested with "pe console" aswell to be sure

sure enough the MessageBoxA with "Some String" was called when i ran the exe without problem, are you sure your naming it "MY.DLL" ?

_________________
redghost.ca

12 Jan 2006, 03:45

madmatt

Joined: 07 Oct 2003
Posts: 1045
Location: Michigan, USA

madmatt 12 Jan 2006, 08:31

A couple of suggestions:

Code:

format PE GUI 4.0 DLL

also, I'm not an expert on java, but I think it uses c style parameters,
so you would need a procedure defined like this:

Code:

proc c readString pStr

the c being use for the c calling convention, to test you would need to use the cinvoke, I think.

12 Jan 2006, 08:31

Fungos Bauux

Joined: 19 Jan 2005
Posts: 31
Location: CWB

Fungos Bauux 12 Jan 2006, 16:14

Quote:

are you sure your naming it "MY.DLL" ?

yup..

very strange, yours code works fine here. but mine doesnt, maybe my readString with only a ret is the problem? anyone can verify this?

@madmatt:

Thanks, I will need that. But fasm isnt accepting "proc c readString pStr" it gives error at "endp".

cinvoke fasm compiled.

12 Jan 2006, 16:14

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8250
Location: Kraków, Poland

Tomasz Grysztar 12 Jan 2006, 16:54

Please look at the section "Problems" in the Windows FAQ (it's the sticky thread in this forum) - there are two threads that refer exactly to the problem you've got here.

Fungos Bauux wrote:

Thanks, I will need that. But fasm isnt accepting "proc c readString pStr" it gives error at "endp".

It should be "proc readString c pStr". Look here for the complete information on the "proc" macro syntax.

12 Jan 2006, 16:54

Fungos Bauux

Joined: 19 Jan 2005
Posts: 31
Location: CWB

Fungos Bauux 12 Jan 2006, 18:00

Sorry Tomasz, but I have read that threads, but I was thinking mine wasnt related.

Thank you guys. Smile

12 Jan 2006, 18:00

madmatt

Joined: 07 Oct 2003
Posts: 1045
Location: Michigan, USA

madmatt 13 Jan 2006, 02:13

Sorry for that mistake, Fungos Bauux

13 Jan 2006, 02:13

< Last Thread | Next Thread >

Forum Rules:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum