diff --git a/src/daemon/utils_subst.c b/src/daemon/utils_subst.c
--- /dev/null
+++ b/src/daemon/utils_subst.c
@@ -0,0 +1,149 @@
+/**
+ * collectd - src/utils_subst.c
+ * Copyright (C) 2008 Sebastian Harl
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ * Sebastian "tokkee" Harl <sh at tokkee.org>
+ **/
+
+/*
+ * This module provides functions for string substitution.
+ */
+
+#include "collectd.h"
+#include "common.h"
+
+char *subst (char *buf, size_t buflen, const char *string, int off1, int off2,
+ const char *replacement)
+{
+ char *buf_ptr = buf;
+ size_t len = buflen;
+
+ if ((NULL == buf) || (0 >= buflen) || (NULL == string)
+ || (0 > off1) || (0 > off2) || (off1 > off2)
+ || (NULL == replacement))
+ return NULL;
+
+ sstrncpy (buf_ptr, string,
+ ((size_t)off1 + 1 > buflen) ? buflen : (size_t)off1 + 1);
+ buf_ptr += off1;
+ len -= off1;
+
+ if (0 >= len)
+ return buf;
+
+ sstrncpy (buf_ptr, replacement, len);
+ buf_ptr += strlen (replacement);
+ len -= strlen (replacement);
+
+ if (0 >= len)
+ return buf;
+
+ sstrncpy (buf_ptr, string + off2, len);
+ return buf;
+} /* subst */
+
+char *asubst (const char *string, int off1, int off2, const char *replacement)
+{
+ char *buf;
+ int len;
+
+ char *ret;
+
+ if ((NULL == string) || (0 > off1) || (0 > off2) || (off1 > off2)
+ || (NULL ==replacement))
+ return NULL;
+
+ len = off1 + strlen (replacement) + strlen (string) - off2 + 1;
+
+ buf = (char *)malloc (len);
+ if (NULL == buf)
+ return NULL;
+
+ ret = subst (buf, len, string, off1, off2, replacement);
+ if (NULL == ret)
+ free (buf);
+ return ret;
+} /* asubst */
+
+char *subst_string (char *buf, size_t buflen, const char *string,
+ const char *needle, const char *replacement)
+{
+ char *temp;
+ size_t needle_len;
+ size_t i;
+
+ if ((buf == NULL) || (string == NULL)
+ || (needle == NULL) || (replacement == NULL))
+ return (NULL);
+
+ temp = (char *) malloc (buflen);
+ if (temp == NULL)
+ {
+ ERROR ("subst_string: malloc failed.");
+ return (NULL);
+ }
+
+ needle_len = strlen (needle);
+ strncpy (buf, string, buflen);
+
+ /* Limit the loop to prevent endless loops. */
+ for (i = 0; i < buflen; i++)
+ {
+ char *begin_ptr;
+ size_t begin;
+
+ /* Find `needle' in `buf'. */
+ begin_ptr = strstr (buf, needle);
+ if (begin_ptr == NULL)
+ break;
+
+ /* Calculate the start offset. */
+ begin = begin_ptr - buf;
+
+ /* Substitute the region using `subst'. The result is stored in
+ * `temp'. */
+ begin_ptr = subst (temp, buflen, buf,
+ begin, begin + needle_len,
+ replacement);
+ if (begin_ptr == NULL)
+ {
+ WARNING ("subst_string: subst failed.");
+ break;
+ }
+
+ /* Copy the new string in `temp' to `buf' for the next round. */
+ strncpy (buf, temp, buflen);
+ }
+
+ if (i >= buflen)
+ {
+ WARNING ("subst_string: Loop exited after %zu iterations: "
+ "string = %s; needle = %s; replacement = %s;",
+ i, string, needle, replacement);
+ }
+
+ sfree (temp);
+ return (buf);
+} /* char *subst_string */
+
+/* vim: set sw=4 ts=4 tw=78 noexpandtab : */
+