Question

I need to know the IOCTL constants for the various strings (for example the value of the constant of IOCTL_ATA_PASS_THROUGH). Searching the net I found that those constants are defined in the header Ntddscsi.h but those constant are wrong. For example the constant value of IOCTL_ATA_PASS_THROUGH should be 4D02C while in the header file it is 40B

The question is: where can I find a list with ALL the right values?

Thanks

EDIT:

I’ve found http://www.ioctls.net/ where there are listed all the codes. Thanks anyway for the explanation of why the value in Ntddscsi.h is not the “final” value

Answer 1

They are in ntddscsi.h found at c:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Include\ (on a 64 bit system). They are defied as:

#define IOCTL_ATA_PASS_THROUGH          CTL_CODE(IOCTL_SCSI_BASE, 0x040b, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)

and IOCTL_SCSI_BASE is

#define IOCTL_SCSI_BASE                 FILE_DEVICE_CONTROLLER

from the same file

and these from WinIoCtl.h

#define METHOD_BUFFERED                 0
#define FILE_DEVICE_CONTROLLER          0x00000004
#define FILE_READ_ACCESS          ( 0x0001 )    // file & pipe
#define FILE_WRITE_ACCESS         ( 0x0002 )    // file & pipe

and CTL_CODE comes from WinIoCtl.h found at c:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Include\

#define CTL_CODE( DeviceType, Function, Method, Access ) (                 \
((DeviceType) << 16) | ((Access) << 14) | ((Function) << 2) | (Method) \

)

so your final value for IOCTL_ATA_PASS_THROUGH will be:

(4 << 16 | (1 | 2) << 14 | 0x040b << 2 | 0) = 315436 = 4D02C 

😀

And if you will apply these calculations to the other IO_…. macros you will find the values. On the other end it’s much easier to write a short application just to print out their values as hex 😉