How to convert "DeviceIoControl()" of Windows to Go

[christian...@gmx.net]

Hi there,

I'm currently a little lost in the "syscall" space of Go. I tried to migrate a the following code from C to Go:

DeviceIoControl(fd, IOCTL_FUNCTION, &flag, sizeof(flag), &flag, sizeof(flag), &len, NULL)

But there isn't such a low level function in Go, so I rewrote the "CTL_CODE" Macro from Windows

and tried instead (don't hit me, I'm not very expirienced with Windows and the arguments fitted):

code := CtlCode(FILE_DEVICE_UNKNOWN, IOCTL_FUNCTION, METHOD_BUFFERED, FILE_ANY_ACCESS)

err = syscall.WSAIoctl(handle, code, &flag[0], flagLen, &flag[0], flagLen, &retLen, nil, 0)

if err != nil { ... 

But I allways get an error like "An operation was attempted on something that is not a socket".

I know that, because I try to access an opened character device ...

Question: What is the correct way of converting the "DeviceIoControl()" into Go ?

Thanx a lot,

C.

[brainman]

On Thursday, 27 June 2013 07:19:16 UTC+10, christian...@gmx.net wrote:

I'm currently a little lost in the "syscall" space of Go. I tried to migrate a the following code from C to Go:

DeviceIoControl(fd, IOCTL_FUNCTION, &flag, sizeof(flag), &flag, sizeof(flag), &len, NULL)

Show us a complete small program. We will help you to fix it.

Alex

[christian...@gmx.net]

Of course - here is the snippet ...

http://ideone.com/api/embed.js/link/aZpsr5

I'm afraid, but ...

- the error is not the equal (don't ask me why - it's a copy-n-paste. It seems I had to init the WSAxxx function somhow)

- the general question is the same: Which is the correct function to use to replace of DeviceIoControl() !?

Thank you,

C.

[christian...@gmx.net]

Once again the link - and without the tinsel ...

http://ideone.com/aZpsr5

[brainman]

On Thursday, 27 June 2013 20:31:42 UTC+10, christian...@gmx.net wrote:

> ... Which is the correct function to use to replace of DeviceIoControl() !?

If the spec says you must use DeviceIoControl, then nothing else will do. Just use DeviceIoControl. Since DeviceIoControl does not exist in syscall, you have to find it yourself. All these live in dlls, so it is quite simple.

The quick and dirty way is similar to: http://play.golang.org/p/KjypOYjzTD. I was playing with Windows memory, but you should get the idea. Be careful, because no one verify your call parameters, so Windows expect everything to be precise - number of parameters, their types/sizes, their alignment. If you make mistake, you are dead.

Let me know, if you need more help.

Alex

[christian...@gmx.net]

Thanx a lot, but the yellow sponge would say ... "alga grits"

C.

[christian...@gmx.net]

Again "muchos gracias" - it worked, and only because of your perfect answer.

- Basically it was very easy, but

- I spend a lot of time, because one of the dll constants started with 1, and

- the converting in Go (here from/to uintptr) is allways time consuming pain for me

- And I didn't implement overlapping support and such spicy things.

Jipiie,

C.