ReadUnicodeStringFromMode function (usermode_accessors.h)

The ReadUnicodeStringFromMode function safely reads a UNICODE_STRING structure from memory based on the specified processor mode.

Syntax

UNICODE_STRING ReadUnicodeStringFromMode(
  const UNICODE_STRING *Source,
  KPROCESSOR_MODE      Mode
);

Parameters

Source

[in] A pointer to the memory ___location from which to read the UNICODE_STRING structure.

Mode

[in] The processor mode that determines how the memory access is performed. Mode can be one of the following values.

Return value

ReadUnicodeStringFromMode returns the UNICODE_STRING structure read from the specified memory address.

Remarks

This function provides a safe way to read a UNICODE_STRING structure from memory, with extra safety checks when accessing user-mode memory. It ensures that the provided address is valid and accessible based on the specified processor mode.

This function doesn't enforce alignment.

It raises a structured exception if the memory access fails, such as when the source address is inaccessible or is invalid for the specified mode.

This function will never be optimized away by the compiler, nor will the compiler create additional accesses to this memory ___location before the function is called or after the function returns (unless the source code explicitly performs these accesses). The memory access is performed with memory_order_relaxed semantics.

This function works on all versions of Windows, not just the latest. You need to consume the latest WDK to get the function declaration from the usermode_accessors.h header. You also need the library (umaccess.lib) from the latest WDK. However, the resulting driver will run fine on older versions of Windows.

Requirements

See also

ReadUnicodeStringFromUser

WriteUnicodeStringToMode