RtlUnicodeStringVPrintf - NtDoc
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headers
#ifndef _NTSTRSAFE_H_INCLUDED_
#ifndef NTSTRSAFE_LIB_IMPL
#ifndef NTSTRSAFE_NO_UNICODE_STRING_FUNCTIONS
/*++
NTSTATUS
RtlUnicodeStringVPrintf(
_Inout_ PUNICODE_STRING DestinationString,
_In_ _Printf_format_string_ PCWSTR pszFormat,
_In_ va_list argList
);
Routine Description:
This routine is a safer version of the C built-in function 'vsprintf' for
PUNICODE_STRINGs.
This function returns an NTSTATUS value, and not a pointer. It returns
STATUS_SUCCESS if the string was printed without truncation, otherwise it
will return a failure code. In failure cases it will return a truncated
version of the ideal result.
Arguments:
DestinationString - pointer to the counted unicode destination string
pszFormat - format string which must be null terminated
argList - va_list from the variable arguments according to the
stdarg.h convention
Notes:
Behavior is undefined if destination, format strings or any arguments
strings overlap.
DestinationString and pszFormat should not be NULL. See RtlUnicodeStringVPrintfEx if you
require the handling of NULL values.
Return Value:
STATUS_SUCCESS - if there was sufficient space in the dest buffer for
the resultant string
failure - the operation did not succeed
STATUS_BUFFER_OVERFLOW
Note: This status has the severity class Warning - IRPs completed with this
status do have their data copied back to user mode
- this return value is an indication that the print
operation failed due to insufficient space. When this
error occurs, the destination buffer is modified to
contain a truncated version of the ideal result. This is
useful for situations where truncation is ok.
It is strongly recommended to use the NT_SUCCESS() macro to test the
return value of this function
--*/
NTSTRSAFEDDI
RtlUnicodeStringVPrintf(
_Inout_ PUNICODE_STRING DestinationString,
_In_ _Printf_format_string_ NTSTRSAFE_PCWSTR pszFormat,
_In_ va_list argList)
{
NTSTATUS status;
wchar_t* pszDest;
size_t cchDest;
status = RtlUnicodeStringValidateDestWorker(DestinationString,
&pszDest,
&cchDest,
NULL,
NTSTRSAFE_UNICODE_STRING_MAX_CCH,
0);
if (NT_SUCCESS(status))
{
size_t cchNewDestLength = 0;
status = RtlWideCharArrayVPrintfWorker(pszDest,
cchDest,
&cchNewDestLength,
pszFormat,
argList);
// safe to multiply cchNewDestLength * sizeof(wchar_t) since cchDest < NTSTRSAFE_UNICODE_STRING_MAX_CCH and sizeof(wchar_t) is 2
DestinationString->Length = (USHORT)(cchNewDestLength * sizeof(wchar_t));
}
return status;
}
View code on GitHub// ntstrsafe.h
NTSTRSAFEDDI RtlUnicodeStringVPrintf(
[out] PUNICODE_STRING DestinationString,
[in] NTSTRSAFE_PCWSTR pszFormat,
[in] va_list argList
);
View the official Windows Driver Kit DDI referenceNo description available.
The RtlUnicodeStringVPrintf function creates a text string, with formatting that is based on supplied formatting information, and stores the string in a UNICODE_STRING structure.
DestinationString [out]A pointer to a UNICODE_STRING structure that receives a formatted string. RtlUnicodeStringVPrintf creates this string from the formatting string that pszFormat specifies and the function's argument list. The maximum number of characters in the string is NTSTRSAFE_UNICODE_STRING_MAX_CCH.
pszFormat [in]A pointer to a null-terminated text string that contains printf-styled formatting directives.
argList [in]A va_list-typed argument list. Arguments in this argument list will be interpreted by using the formatting string that pszFormat specifies.
RtlUnicodeStringVPrintf returns one of the following NTSTATUS values.
| Return code | Description |
|---|---|
| STATUS_SUCCESS | This success status means source data was present, the string was copied without truncation, and the resultant destination buffer is null-terminated. |
| STATUS_BUFFER_OVERFLOW | This warning status means the copy operation did not complete due to insufficient buffer space. The destination buffer contains a truncated, null-terminated version of the intended result. |
| STATUS_INVALID_PARAMETER | This error status means the function received an invalid input parameter. For more information, see the following paragraph. |
RtlUnicodeStringVPrintf returns the STATUS_INVALID_PARAMETER value when one of the following occurs:
For information about how to test NTSTATUS values, see Using NTSTATUS Values.
The RtlUnicodeStringVPrintf function uses the destination buffer's size to ensure that the string formatting operation does not write past the end of the buffer. The function does not terminate the resultant string with a null character.
If the format string and destination string overlap, the behavior of the function is undefined.
The pszFormat and DestinationString pointers cannot be NULL. If you need to handle NULL pointer values, use the RtlUnicodeStringVPrintfEx function.
For more information about the safe string functions, see Using Safe String Functions.