Added function to a file's path from a handle (file descriptor).

diff --git a/include/MUtils/OSSupport.h b/include/MUtils/OSSupport.h
index 18df60d..ec429b7 100644 (file)
--- a/include/MUtils/OSSupport.h
+++ b/include/MUtils/OSSupport.h
@@ -181,6 +181,9 @@ namespace MUtils
                //Shell notification
                MUTILS_API void shell_change_notification(void);
 
+               //Get file path from descriptor
+               MUTILS_API QString get_file_path(const int &fd);
+
                //WOW64 redirection
                MUTILS_API bool wow64fsredir_disable(void *oldValue);
                MUTILS_API bool wow64fsredir_revert (void *oldValue);

diff --git a/src/OSSupport_Win32.cpp b/src/OSSupport_Win32.cpp
index be00e95..1a483f5 100644 (file)
--- a/src/OSSupport_Win32.cpp
+++ b/src/OSSupport_Win32.cpp
@@ -716,6 +716,147 @@ quint64 MUtils::OS::current_file_time(void)
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// FILE PATH FROM FD
+///////////////////////////////////////////////////////////////////////////////
+
+typedef DWORD(_stdcall *GetPathNameByHandleFun)(HANDLE hFile, LPWSTR lpszFilePath, DWORD cchFilePath, DWORD dwFlags);
+
+static QReadWriteLock           g_getFilePath_lock;
+static QScopedPointer<QLibrary> g_getFilePath_kernel32;
+static GetPathNameByHandleFun   g_getFilePath_prt = NULL;
+
+static QString get_file_path_drive_list(void)
+{
+       QString list;
+       const DWORD len = GetLogicalDriveStringsW(0, NULL);
+       if (len > 0)
+       {
+               if (wchar_t *const buffer = (wchar_t*) _malloca(sizeof(wchar_t) * len))
+               {
+                       const DWORD ret = GetLogicalDriveStringsW(len, buffer);
+                       if ((ret > 0) && (ret < len))
+                       {
+                               const wchar_t *ptr = buffer;
+                               while (const size_t current_len = wcslen(ptr))
+                               {
+                                       list.append(QChar(*reinterpret_cast<const ushort*>(ptr)));
+                                       ptr += (current_len + 1);
+                               }
+                       }
+                       _freea(buffer);
+               }
+       }
+       return list;
+}
+
+static QString &get_file_path_translate(QString &path)
+{
+       static const DWORD BUFSIZE = 4096;
+       wchar_t buffer[BUFSIZE], drive[3];
+
+       const QString driveList = get_file_path_drive_list();
+       wcscpy_s(drive, 3, L"?:");
+       for (const wchar_t *current = MUTILS_WCHR(driveList); *current; current++)
+       {
+               drive[0] = (*current);
+               if (QueryDosDeviceW(drive, buffer, MAX_PATH))
+               {
+                       const QString prefix = MUTILS_QSTR(buffer);
+                       if (path.startsWith(prefix, Qt::CaseInsensitive))
+                       {
+                               path.remove(0, prefix.length()).prepend(QLatin1Char(':')).prepend(QChar(*reinterpret_cast<const ushort*>(current)));
+                               break;
+                       }
+               }
+       }
+
+       return path;
+}
+
+static QString get_file_path_fallback(const HANDLE &hFile)
+{
+       QString filePath;
+
+       const HANDLE hFileMap = CreateFileMappingW(hFile, NULL, PAGE_READONLY, 0, 1, NULL);
+       if (hFileMap)
+       {
+               void* pMem = MapViewOfFile(hFileMap, FILE_MAP_READ, 0, 0, 1);
+               if (pMem)
+               {
+                       static const DWORD BUFSIZE = 4096;
+                       wchar_t buffer[BUFSIZE];
+                       if (GetMappedFileNameW(GetCurrentProcess(), pMem, buffer, BUFSIZE))
+                       {
+                               filePath = get_file_path_translate(MUTILS_QSTR(buffer));
+                       }
+                       UnmapViewOfFile(pMem);
+               }
+               CloseHandle(hFileMap);
+       }
+
+       return filePath;
+}
+
+static bool get_file_path_init()
+{
+       QWriteLocker writeLock(&g_getFilePath_lock);
+       if (g_getFilePath_prt)
+       {
+               return true; /*already initialized*/
+       }
+
+       if (g_getFilePath_kernel32.isNull())
+       {
+               g_getFilePath_kernel32.reset(new QLibrary("kernel32.dll"));
+       }
+
+       if (!g_getFilePath_kernel32->isLoaded())
+       {
+               if (!g_getFilePath_kernel32->load())
+               {
+                       return false; /*faild to load kernel32.dll*/
+               }
+       }
+
+       g_getFilePath_prt = (GetPathNameByHandleFun) g_getFilePath_kernel32->resolve("GetFinalPathNameByHandleW");
+       return (g_getFilePath_prt != NULL);
+}
+
+QString MUtils::OS::get_file_path(const int &fd)
+{
+       if (fd >= 0)
+       {
+               QReadLocker readLock(&g_getFilePath_lock);
+
+               if (!g_getFilePath_prt)
+               {
+                       readLock.unlock();
+                       if (!get_file_path_init())
+                       {
+                               qWarning("MUtils::OS::get_file_path() --> fallback!");
+                               return get_file_path_fallback((HANDLE)_get_osfhandle(fd));
+                       }
+                       readLock.relock();
+               }
+
+               const HANDLE handle = (HANDLE) _get_osfhandle(fd);
+               const DWORD len = g_getFilePath_prt(handle, NULL, 0, FILE_NAME_OPENED);
+               if (len > 0)
+               {
+                       wchar_t *const buffer = (wchar_t*) _malloca(sizeof(wchar_t) * len);
+                       const DWORD ret = g_getFilePath_prt(handle, buffer, len, FILE_NAME_OPENED);
+                       if ((ret > 0) && (ret < len))
+                       {
+                               const QString path(MUTILS_QSTR(buffer));
+                               return path.startsWith(QLatin1String("\\\\?\\")) ? path.mid(4) : path;
+                       }
+               }
+       }
+
+       return QString();
+}
+
+///////////////////////////////////////////////////////////////////////////////
 // PROCESS ELEVATION
 ///////////////////////////////////////////////////////////////////////////////