Index: /trunk/include/iprt/mangling.h
===================================================================
--- /trunk/include/iprt/mangling.h	(revision 79569)
+++ /trunk/include/iprt/mangling.h	(revision 79570)
@@ -1644,4 +1644,5 @@
 # define RTPathParsedReassemble                         RT_MANGLER(RTPathParsedReassemble)
 # define RTPathParseSimple                              RT_MANGLER(RTPathParseSimple)
+# define RTPathPurgeFilename                            RT_MANGLER(RTPathPurgeFilename)
 # define RTPathQueryInfo                                RT_MANGLER(RTPathQueryInfo)
 # define RTPathQueryInfoEx                              RT_MANGLER(RTPathQueryInfoEx)
Index: /trunk/include/iprt/path.h
===================================================================
--- /trunk/include/iprt/path.h	(revision 79569)
+++ /trunk/include/iprt/path.h	(revision 79570)
@@ -454,4 +454,16 @@
  */
 RTDECL(char *) RTPathChangeToUnixSlashes(char *pszPath, bool fForce);
+
+/**
+ * Purges a string so it can be used as a file according to fFlags.
+ *
+ * Illegal filename characters are replaced by '_'.
+ *
+ * @returns pszString
+ * @param   pszString   The string to purge.
+ * @param   fFlags      One of the RTPATH_STR_F_STYLE_XXX flags.  Most users
+ *                      will pass RTPATH_STR_F_STYLE_HOST (0).
+ */
+RTDECL(char *) RTPathPurgeFilename(char *pszString, uint32_t fFlags);
 
 /**
Index: /trunk/src/VBox/Runtime/Makefile.kmk
===================================================================
--- /trunk/src/VBox/Runtime/Makefile.kmk	(revision 79569)
+++ /trunk/src/VBox/Runtime/Makefile.kmk	(revision 79570)
@@ -533,4 +533,5 @@
 	common/path/RTPathParsedReassemble.cpp \
 	common/path/RTPathParseSimple.cpp \
+	common/path/RTPathPurgeFilename.cpp \
 	common/path/RTPathRealDup.cpp \
 	common/path/RTPathRmCmd.cpp \
Index: /trunk/src/VBox/Runtime/common/path/RTPathPurgeFilename.cpp
===================================================================
--- /trunk/src/VBox/Runtime/common/path/RTPathPurgeFilename.cpp	(revision 79570)
+++ /trunk/src/VBox/Runtime/common/path/RTPathPurgeFilename.cpp	(revision 79570)
@@ -0,0 +1,121 @@
+/* $Id$ */
+/** @file
+ * IPRT - RTPathPurgeFilename
+ */
+
+/*
+ * Copyright (C) 2006-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include "internal/iprt.h"
+#include <iprt/path.h>
+
+#include <iprt/assert.h>
+#include <iprt/string.h>
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+/** Character mappings for translating a string into a valid Windows or OS/2 filename. */
+static const unsigned char g_auchWinOs2Map[256] =
+{
+      0, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95, 95,
+     32, 33, 95, 35, 36, 37, 38, 39, 40, 41, 95, 43, 44, 45, 46, 95, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 95, 59, 95, 61, 95, 95,
+     64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 95, 93, 94, 95,
+     96, 97, 98, 99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123, 95,125,126, 95,
+    128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,
+    160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,
+    192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,
+    224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255
+};
+
+/* Program for generating the table:
+#include <stdio.h>
+#include <string.h>
+int main()
+{
+    int i;
+    printf("static const unsigned char g_auchWinOs2Map[256] =\n"
+           "{");
+    for (i = 0; i < 256; i++)
+    {
+        int ch = i;
+        if (   i <= 31
+            || i == 127
+            || (i < 127 && strchr("/\\*:<>?|\"",  (char)i) != NULL))
+            ch = i > 0 ? '_' : 0;
+        if (i == 0)
+            printf("\n    %3d", ch);
+        else if ((i % 32) == 0)
+            printf(",\n    %3d", ch);
+        else
+            printf(",%3d", ch);
+    }
+    printf("\n"
+           "};\n");
+    return 0;
+}
+*/
+
+
+RTDECL(char *) RTPathPurgeFilename(char *pszString, uint32_t fFlags)
+{
+    AssertPtrReturn(pszString, NULL);
+    Assert(RTPATH_STR_F_IS_VALID(fFlags, 0));
+
+    /*
+     * Take action according to the style after first resolving the host style.
+     */
+    if ((fFlags & RTPATH_STR_F_STYLE_MASK) == RTPATH_STR_F_STYLE_HOST)
+        fFlags = (fFlags & ~RTPATH_STR_F_STYLE_MASK) | RTPATH_STYLE;
+    if ((fFlags & RTPATH_STR_F_STYLE_MASK) == RTPATH_STR_F_STYLE_DOS)
+    {
+        /*
+         * Produce a filename valid on Windows and OS/2.
+         * Here all control characters (including tab) and path separators needs to
+         * be replaced, in addition to a scattering of other ones.
+         */
+        unsigned char *puch = (unsigned char *)pszString;
+        uintptr_t      uch;
+        while ((uch = *puch))
+            *puch++ = g_auchWinOs2Map[uch];
+    }
+    else
+    {
+        /*
+         * Produce a filename valid on a (typical) Unix system.
+         * Here only the '/' needs to be replaced.
+         */
+        Assert((fFlags & RTPATH_STR_F_STYLE_MASK) == RTPATH_STR_F_STYLE_UNIX);
+        char *pszSlash = strchr(pszString, '/');
+        while (pszSlash != NULL)
+        {
+            *pszSlash = '_';
+            pszSlash = strchr(pszSlash + 1, '/');
+        }
+    }
+    return pszString;
+}
+
Index: /trunk/src/VBox/Runtime/testcase/tstRTPath.cpp
===================================================================
--- /trunk/src/VBox/Runtime/testcase/tstRTPath.cpp	(revision 79569)
+++ /trunk/src/VBox/Runtime/testcase/tstRTPath.cpp	(revision 79570)
@@ -251,4 +251,34 @@
                              i, cchParent2, cchExpected, s_aTests[i].pszPath);
         }
+    }
+}
+
+
+static void testPurgeFilename(RTTEST hTest)
+{
+    static struct
+    {
+        const char *pszIn, *pszOut;
+        uint32_t    fFlags;
+    } const s_aTests[] =
+    {
+        { "start///end",            "start___end",      RTPATH_STR_F_STYLE_UNIX },
+        { "start///end",            "start___end",      RTPATH_STR_F_STYLE_DOS },
+        { "start///end",            "start___end",      RTPATH_STR_F_STYLE_HOST },
+        { "1:<>\\9",                "1:<>\\9",          RTPATH_STR_F_STYLE_UNIX },
+        { "1:<>\\9",                "1____9",           RTPATH_STR_F_STYLE_DOS },
+        { "\t\r\n",                 "\t\r\n",           RTPATH_STR_F_STYLE_UNIX },
+        { "\t\r\n",                 "___",              RTPATH_STR_F_STYLE_DOS },
+    };
+    RTTestSub(hTest, "RTPathPurgeFilename");
+    for (uint32_t i = 0; i < RT_ELEMENTS(s_aTests); i++)
+    {
+        char szPath[RTPATH_MAX];
+        strcpy(szPath, s_aTests[i].pszIn);
+        char *pszRet = RTPathPurgeFilename(szPath, s_aTests[i].fFlags);
+        RTTEST_CHECK(hTest, pszRet == &szPath[0]);
+        if (strcmp(szPath, s_aTests[i].pszOut) != 0)
+            RTTestFailed(hTest, "sub-test #%u: got '%s', expected '%s' (style %#x)",
+                         i, szPath, s_aTests[i].pszOut, s_aTests[i].fFlags);
     }
 }
@@ -983,4 +1013,5 @@
     testParserAndSplitter(hTest);
     testParentLength(hTest);
+    testPurgeFilename(hTest);
 
     /*
