first commit for openGauss connect odbc code

xalibname.c

@@ -0,0 +1,91 @@
+/*------
+ * Module:			xalibname.c
+ *
+ * Description:
+ *		This module gets the (path) name of xalib.
+ *
+ *-------
+ */
+
+#ifdef	_HANDLE_ENLIST_IN_DTC_
+
+#ifndef	_WIN32_WINNT
+#define	_WIN32_WINNT	0x0400
+#endif	/* _WIN32_WINNT */
+
+#define	WIN32_LEAN_AND_MEAN
+
+#include <windows.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern HMODULE	s_hModule;
+
+static char	xalibpath[_MAX_PATH] = "";
+static char	xalibname[_MAX_FNAME] = "";
+
+static const char * const PGMFILES = "Program Files";
+static const char * const PGMFILESX86 = "Program Files (x86)";
+
+typedef BOOL (WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);
+LPFN_ISWOW64PROCESS fnIsWow64Process;
+
+BOOL IsWow64()
+{
+	static BOOL bCalled = FALSE;
+	static BOOL bIsWow64 = FALSE;
+
+	if (bCalled)
+		return bIsWow64;
+	fnIsWow64Process = (LPFN_ISWOW64PROCESS) GetProcAddress(
+		GetModuleHandle("kernel32"), "IsWow64Process");
+
+	if (NULL != fnIsWow64Process)
+	{
+		if (!fnIsWow64Process(GetCurrentProcess(), &bIsWow64))
+		{
+			//handle error
+		}
+	}
+	bCalled = TRUE;
+	return bIsWow64;
+}
+
+const char *GetXaLibName(void)
+{
+	char	dllpath[_MAX_PATH], drive[_MAX_DRIVE], dir[_MAX_DIR],
+		fname[_MAX_FNAME], ext[_MAX_EXT];
+	if (!xalibpath[0])
+	{
+		size_t	pgmflen = strlen(PGMFILESX86);
+		char	*ptr;
+
+		GetModuleFileName(s_hModule, dllpath, sizeof(dllpath));
+		/* In Windows XP SP2, the dllname should be specified */
+		/* instead of the dll path name, because it looks up */
+		/* the HKLM\Microfost\MSDTC\XADLL\(dllname) registry */
+		/* entry for security reason. */
+		_splitpath(dllpath, drive, dir, fname, ext);
+		strncpy(xalibname, "pgxalib.dll", sizeof(xalibname));
+		if (IsWow64())
+		{
+			if ('\\' == *dir &&
+		    	    0 == _strnicmp(dir + 1, PGMFILESX86, pgmflen))
+			{
+				ptr = dir + 1 + pgmflen;
+				if ('\\' == *ptr)
+					_snprintf(xalibpath, sizeof(xalibpath), "%s\\%s%s%s", drive, PGMFILES, ptr, xalibname);
+			}
+		}
+		else 	
+			_snprintf(xalibpath, sizeof(xalibpath), "%s%s%s", drive, dir, xalibname);
+	}
+	return xalibname;
+}
+
+const char *GetXaLibPath(void)
+{
+	GetXaLibName();
+	return xalibpath;
+}
+#endif /* _HANDLE_ENLIST_IN_DTC_ */