Add InitializeObjectAttributes function with example to ntddk.rs

[0xflux]

Summary

This PR adds the InitializeObjectAttributes function to ntddk.rs. The function initialises the OBJECT_ATTRIBUTES structure, which is used by Windows kernel APIs for object management. The function ensures pointer safety and proper initialisation of fields within the structure, hopefully making it somewhat safe to use. I have included unsafe in the function signature to alert the caller to pointer dereferencing, though the unsafe keyword strictly isn't required due to the inner unsafe block.

I don't know whether you want this style of documentation in this crate; if you want it removing, please let me know! I'm new to contributing to this project, so I am open to feedback.

Changes Made

• Function: Added InitializeObjectAttributes
  • Ensures safety by checking for null pointers before dereferencing.
  • Returns Ok(()) for successful initialisation or Err(()) if the pointer is invalid.
  • Modifies the OBJECT_ATTRIBUTES structure using an unsafe block.
• Example:
  • Demonstrates initialising a UNICODE_STRING.
  • Includes attribute constants (OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE) for clarity.
  • Provides error handling for the result of the function.

Original C macro for reference

The original implementation in the WDK can be found below for reference to my PR:

#define InitializeObjectAttributes( p, n, a, r, s ) { \
    (p)->Length = sizeof( OBJECT_ATTRIBUTES );          \
    (p)->RootDirectory = r;                             \
    (p)->Attributes = a;                                \
    (p)->ObjectName = n;                                \
    (p)->SecurityDescriptor = s;                        \
    (p)->SecurityQualityOfService = NULL;               \
    }