How to get the name of a file from a file handle in Windows using C?

I'm trying to retrieve a file name from a given file handle.

I've seen that GetFileInformationByHandle could be useful, but the structure it returns does not contain any file name information (http://msdn.microsoft.com/en-us/library/aa363788%28v=VS.85%29.aspx).

How can I do this?

EDIT:

I've tried installing the Windows FileID APIs to get GetFileInformationByHandleEx working on Windows XP. But when including fileextd.h I get the following errors

c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(16) : error C2011: '_FILE_INFO_BY_HANDLE_CLASS' : 'enum' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13900) : see declaration of '_FILE_INFO_BY_HANDLE_CLASS'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(32) : error C2011: '_FILE_BASIC_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13917) : see declaration of '_FILE_BASIC_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(40) : error C2011: '_FILE_STANDARD_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13925) : see declaration of '_FILE_STANDARD_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(48) : error C2011: '_FILE_NAME_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13933) : see declaration of '_FILE_NAME_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(53) : error C2011: '_FILE_RENAME_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13938) : see declaration of '_FILE_RENAME_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(60) : error C2011: '_FILE_ALLOCATION_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13945) : see declaration of '_FILE_ALLOCATION_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(64) : error C2011: '_FILE_END_OF_FILE_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13949) : see declaration of '_FILE_END_OF_FILE_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(68) : error C2011: '_FILE_STREAM_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13953) : see declaration of '_FILE_STREAM_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(76) : error C2011: '_FILE_COMPRESSION_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13961) : see declaration of '_FILE_COMPRESSION_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(85) : error C2011: '_FILE_ATTRIBUTE_TAG_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13970) : see declaration of '_FILE_ATTRIBUTE_TAG_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(90) : error C201开发者_JAVA百科1: '_FILE_DISPOSITION_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13975) : see declaration of '_FILE_DISPOSITION_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(94) : error C2011: '_FILE_ID_BOTH_DIR_INFO' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(13979) : see declaration of '_FILE_ID_BOTH_DIR_INFO'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(130) : error C2011: '_FILE_ID_TYPE' : 'enum' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(14026) : see declaration of '_FILE_ID_TYPE'
c:\programmi\microsoft visual studio 9.0\vc\include\fileextd.h(135) : error C2011: 'FILE_ID_DESCRIPTOR' : 'struct' type redefinition
        c:\programmi\microsoft sdks\windows\v6.1\include\winbase.h(14032) : see declaration of 'FILE_ID_DESCRIPTOR'
c:\documents and settings\lab\documenti\visual studio 2008\projects\sandbox\sandbox\funcs_files.cpp(26) : error C2079: 'lpFileInformation' uses undefined struct '_FILE_NAME_INFO'
c:\documents and settings\lab\documenti\visual studio 2008\projects\sandbox\sandbox\funcs_files.cpp(35) : error C2228: left of '.FileName' must have class/struct/union
        type is 'int'

From the following code:

#include <windows.h>
#include <fileextd.h>

LPVOID GetFileNameFromHandle(HANDLE hFile) {
    FILE_NAME_INFO lpFileInformation;
    BOOL bWorked;

    bWorked = GetFileInformationByHandleEx(
        hFile,
        FileNameInfo,
        &lpFileInformation,
        sizeof(FILE_NAME_INFO));

    return lpFileInformation.FileName;
}

---

BOOL    GetFileNameFromHandle(HANDLE hFile, TCHAR *pszFileName, const unsigned int uiMaxLen)
{
    pszFileName[0]=0;

    std::unique_ptr<BYTE[]> ptrcFni(new BYTE[_MAX_PATH * sizeof(TCHAR) + sizeof(FILE_NAME_INFO)]);
    FILE_NAME_INFO *pFni = reinterpret_cast<FILE_NAME_INFO *>(ptrcFni.get());

    BOOL b = GetFileInformationByHandleEx(hFile, 
                                        FileNameInfo,
                                        pFni,
                                        sizeof(FILE_NAME_INFO) + (_MAX_PATH * sizeof(TCHAR)) );
    if ( b )
    {
#ifdef  _UNICODE
         wcsncpy_s(pszFileName, 
                min(uiMaxLen, (pFni->FileNameLength / sizeof(pFni->FileName[0])) + 1 ), 
                pFni->FileName, 
                _TRUNCATE);
#else
        strncpy_s(pszFileName, 
                min(uiMaxLen, (pFni->FileNameLength / sizeof(pFni->FileName[0])) + 1), 
                CW2A(pFni->FileName), 
                _TRUNCATE);
#endif
    }
    return b;
}

---

Hi if you need file name from handle you can read this ms article http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx or use this GetFileInformationByHandleEx

---

There is a correct way to do this that works on Windows XP, on both files and directories; I've explained it in another post here.

---

For Vista and later take a look at GetFinalPathNameByHandle (like mehrdad wrote)

It is more convenient IMO and allows more customization than GetFileInformationByHandleEx, and it removes the hassle of allocating a custom size FILE_NAME_INFO struct.

Example:

DWORD size = GetFinalPathNameByHandleW(handle, NULL, 0, VOLUME_NAME_DOS);
if (size == 0) return L"(NOT FOUND)";
std::wstring fname(size, L'0');
size = GetFinalPathNameByHandleW(handle, &fname.front(), size, VOLUME_NAME_DOS);

Notice, it will prepend \\?\ to the returning name.

(I used C++ std::wstring to avoid C boilerplate for memory handling. Use malloc for your needs).

---

Where did you get the file handle from? If you're sure it's not a named pipe handle, you can use NtQueryObject to query the file name.