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/*++
Copyright (c) 1999 - 2002 Microsoft Corporation
Module Name:
operations.c
Abstract:
This is the support routines module of the kernel mode filter driver implementing
context sample.
Environment:
Kernel mode
--*/
#include "pch.h"
//
// Assign text sections for each routine.
//
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, CtxAllocateUnicodeString)
#pragma alloc_text(PAGE, CtxFreeUnicodeString)
#endif
//
// Support Routines
//
_At_(String->Length, _Out_range_(==, 0))
_At_(String->MaximumLength, _In_)
_At_(String->Buffer, _Pre_maybenull_ _Post_notnull_ _Post_writable_byte_size_(String->MaximumLength))
NTSTATUS
CtxAllocateUnicodeString (
_Out_ PUNICODE_STRING String
)
/*++
Routine Description:
This routine allocates a unicode string
Arguments:
String - supplies the size of the string to be allocated in the MaximumLength field
return the unicode string
Return Value:
STATUS_SUCCESS - success
STATUS_INSUFFICIENT_RESOURCES - failure
--*/
{
PAGED_CODE();
String->Buffer = ExAllocatePoolZero( PagedPool,
String->MaximumLength,
CTX_STRING_TAG );
if (String->Buffer == NULL) {
DebugTrace( DEBUG_TRACE_ERROR,
("[Ctx]: Failed to allocate unicode string of size 0x%x\n",
String->MaximumLength) );
return STATUS_INSUFFICIENT_RESOURCES;
}
String->Length = 0;
return STATUS_SUCCESS;
}
_At_(String->Length, _Out_range_(==, 0))
_At_(String->MaximumLength, _Out_range_(==, 0))
_At_(String->Buffer, _Pre_notnull_ _Post_null_)
VOID
CtxFreeUnicodeString (
_Pre_notnull_ PUNICODE_STRING String
)
/*++
Routine Description:
This routine frees a unicode string
Arguments:
String - supplies the string to be freed
Return Value:
None
--*/
{
PAGED_CODE();
ExFreePoolWithTag( String->Buffer,
CTX_STRING_TAG );
String->Length = String->MaximumLength = 0;
String->Buffer = NULL;
}
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