Add alternate string management support.

CHANGES.md

@@ -9,6 +9,8 @@
   `MXML_TYPE_DIRECTIVE` node types (Issue #250)
 - Added `mxmlLoadFilename` and `mxmlSaveFilename` functions (Issue #291)
 - Added AFL fuzzing support (Issue #306)
+- Added string copy/free callbacks to support alternate memory management of
+  strings.
 - Renamed `mxml_type_t` enumerations to `MXML_TYPE_xxx` (Issue #251)
 - Updated APIs to use bool type instead of an int representing a boolean value.
 - Updated the SAX callback to return a `bool` value to control processing

mxml-attr.c

@@ -45,8 +45,8 @@ mxmlElementDeleteAttr(mxml_node_t *node,// I - Element
     if (!strcmp(attr->name, name))
     {
       // Delete this attribute...
-      free(attr->name);
-      free(attr->value);
+      _mxml_strfree(attr->name);
+      _mxml_strfree(attr->value);
 
       i --;
       if (i > 0)
@@ -165,7 +165,7 @@ mxmlElementSetAttr(mxml_node_t *node,	// I - Element node
 
   if (value)
   {
-    if ((valuec = strdup(value)) == NULL)
+    if ((valuec = _mxml_strcopy(value)) == NULL)
     {
       _mxml_error("Unable to allocate memory for attribute '%s' in element %s.", name, node->value.element.name);
       return;
@@ -177,7 +177,7 @@ mxmlElementSetAttr(mxml_node_t *node,	// I - Element node
   }
 
   if (!mxml_set_attr(node, name, valuec))
-    free(valuec);
+    _mxml_strfree(valuec);
 }
 
 
@@ -212,10 +212,10 @@ mxmlElementSetAttrf(mxml_node_t *node,	// I - Element node
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((value = strdup(buffer)) == NULL)
+  if ((value = _mxml_strcopy(buffer)) == NULL)
     _mxml_error("Unable to allocate memory for attribute '%s' in element %s.", name, node->value.element.name);
   else if (!mxml_set_attr(node, name, value))
-    free(value);
+    _mxml_strfree(value);
 }
 
 
@@ -238,7 +238,7 @@ mxml_set_attr(mxml_node_t *node,	// I - Element node
     if (!strcmp(attr->name, name))
     {
       // Free the old value as needed...
-      free(attr->value);
+      _mxml_strfree(attr->value);
       attr->value = value;
 
       return (true);
@@ -255,7 +255,7 @@ mxml_set_attr(mxml_node_t *node,	// I - Element node
   node->value.element.attrs = attr;
   attr += node->value.element.num_attrs;
 
-  if ((attr->name = strdup(name)) == NULL)
+  if ((attr->name = _mxml_strcopy(name)) == NULL)
   {
     _mxml_error("Unable to allocate memory for attribute '%s' in element %s.", name, node->value.element.name);
     return (false);

mxml-file.c

@@ -527,50 +527,6 @@ mxmlSaveString(
 }
 
 
-//
-// 'mxmlSetCustomHandlers()' - Set the handling functions for custom data.
-//
-// The load function accepts a node pointer and a data string and must
-// return 0 on success and non-zero on error.
-//
-// The save function accepts a node pointer and must return a malloc'd
-// string on success and `NULL` on error.
-//
-
-void
-mxmlSetCustomCallbacks(
-    mxml_custom_load_cb_t load_cb,	// I - Load callback function
-    mxml_custom_save_cb_t save_cb,	// I - Save callback function
-    void                  *cbdata)	// I - Callback data
-{
-  _mxml_global_t *global = _mxml_global();
-					// Global data
-
-
-  global->custom_load_cb = load_cb;
-  global->custom_save_cb = save_cb;
-  global->custom_cbdata  = cbdata;
-}
-
-
-//
-// 'mxmlSetErrorCallback()' - Set the error message callback.
-//
-
-void
-mxmlSetErrorCallback(
-    mxml_error_cb_t cb,			// I - Error callback function
-    void            *cbdata)		// I - Error callback data
-{
-  _mxml_global_t *global = _mxml_global();
-					// Global data
-
-
-  global->error_cb     = cb;
-  global->error_cbdata = cbdata;
-}
-
-
 //
 // 'mxmlSetWrapMargin()' - Set the wrap margin when saving XML data.
 //

mxml-index.c

@@ -33,7 +33,7 @@ mxmlIndexDelete(mxml_index_t *ind)	// I - Index to delete
     return;
 
   // Free memory...
-  free(ind->attr);
+  _mxml_strfree(ind->attr);
   free(ind->nodes);
   free(ind);
 }
@@ -228,7 +228,7 @@ mxmlIndexNew(mxml_node_t *node,		// I - XML node tree
 
   if (attr)
   {
-    if ((ind->attr = strdup(attr)) == NULL)
+    if ((ind->attr = _mxml_strcopy(attr)) == NULL)
     {
       _mxml_error("Unable to allocate memory for index attribute.");
       free(ind);

mxml-node.c

@@ -207,7 +207,7 @@ mxmlNewCDATA(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
   // Create the node and set the name value...
   if ((node = mxml_new(parent, MXML_TYPE_CDATA)) != NULL)
   {
-    if ((node->value.cdata = strdup(data)) == NULL)
+    if ((node->value.cdata = _mxml_strcopy(data)) == NULL)
     {
       _mxml_error("Unable to allocate memory for CDATA.");
       mxmlDelete(node);
@@ -251,7 +251,7 @@ mxmlNewCDATAf(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
     vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
 
-    node->value.cdata = strdup(buffer);
+    node->value.cdata = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -283,7 +283,7 @@ mxmlNewComment(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
   // Create the node and set the name value...
   if ((node = mxml_new(parent, MXML_TYPE_COMMENT)) != NULL)
   {
-    if ((node->value.comment = strdup(comment)) == NULL)
+    if ((node->value.comment = _mxml_strcopy(comment)) == NULL)
     {
       _mxml_error("Unable to allocate memory for comment.");
       mxmlDelete(node);
@@ -327,7 +327,7 @@ mxmlNewCommentf(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
     vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
 
-    node->value.comment = strdup(buffer);
+    node->value.comment = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -391,7 +391,7 @@ mxmlNewDeclaration(
   // Create the node and set the name value...
   if ((node = mxml_new(parent, MXML_TYPE_DECLARATION)) != NULL)
   {
-    if ((node->value.declaration = strdup(declaration)) == NULL)
+    if ((node->value.declaration = _mxml_strcopy(declaration)) == NULL)
     {
       _mxml_error("Unable to allocate memory for declaration.");
       mxmlDelete(node);
@@ -436,7 +436,7 @@ mxmlNewDeclarationf(
     vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
 
-    node->value.declaration = strdup(buffer);
+    node->value.declaration = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -468,7 +468,7 @@ mxmlNewDirective(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
   // Create the node and set the name value...
   if ((node = mxml_new(parent, MXML_TYPE_DIRECTIVE)) != NULL)
   {
-    if ((node->value.directive = strdup(directive)) == NULL)
+    if ((node->value.directive = _mxml_strcopy(directive)) == NULL)
     {
       _mxml_error("Unable to allocate memory for processing instruction.");
       mxmlDelete(node);
@@ -512,7 +512,7 @@ mxmlNewDirectivef(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
     vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
 
-    node->value.directive = strdup(buffer);
+    node->value.directive = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -542,7 +542,7 @@ mxmlNewElement(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
 
   // Create the node and set the element name...
   if ((node = mxml_new(parent, MXML_TYPE_ELEMENT)) != NULL)
-    node->value.element.name = strdup(name);
+    node->value.element.name = _mxml_strcopy(name);
 
   return (node);
 }
@@ -597,7 +597,7 @@ mxmlNewOpaque(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
 
   // Create the node and set the element name...
   if ((node = mxml_new(parent, MXML_TYPE_OPAQUE)) != NULL)
-    node->value.opaque = strdup(opaque);
+    node->value.opaque = _mxml_strcopy(opaque);
 
   return (node);
 }
@@ -635,7 +635,7 @@ mxmlNewOpaquef(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
     vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
 
-    node->value.opaque = strdup(buffer);
+    node->value.opaque = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -695,7 +695,7 @@ mxmlNewText(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
   if ((node = mxml_new(parent, MXML_TYPE_TEXT)) != NULL)
   {
     node->value.text.whitespace = whitespace;
-    node->value.text.string     = strdup(string);
+    node->value.text.string     = _mxml_strcopy(string);
   }
 
   return (node);
@@ -737,7 +737,7 @@ mxmlNewTextf(mxml_node_t *parent,	// I - Parent node or `MXML_NO_PARENT`
     va_end(ap);
 
     node->value.text.whitespace = whitespace;
-    node->value.text.string     = strdup(buffer);
+    node->value.text.string     = _mxml_strcopy(buffer);
   }
 
   return (node);
@@ -854,26 +854,26 @@ mxml_free(mxml_node_t *node)		// I - Node
   switch (node->type)
   {
     case MXML_TYPE_CDATA :
-	free(node->value.cdata);
+	_mxml_strfree(node->value.cdata);
         break;
     case MXML_TYPE_COMMENT :
-	free(node->value.comment);
+	_mxml_strfree(node->value.comment);
         break;
     case MXML_TYPE_DECLARATION :
-	free(node->value.declaration);
+	_mxml_strfree(node->value.declaration);
         break;
     case MXML_TYPE_DIRECTIVE :
-	free(node->value.directive);
+	_mxml_strfree(node->value.directive);
         break;
     case MXML_TYPE_ELEMENT :
-	free(node->value.element.name);
+	_mxml_strfree(node->value.element.name);
 
 	if (node->value.element.num_attrs)
 	{
 	  for (i = 0; i < node->value.element.num_attrs; i ++)
 	  {
-	    free(node->value.element.attrs[i].name);
-	    free(node->value.element.attrs[i].value);
+	    _mxml_strfree(node->value.element.attrs[i].name);
+	    _mxml_strfree(node->value.element.attrs[i].value);
 	  }
 
           free(node->value.element.attrs);
@@ -883,13 +883,13 @@ mxml_free(mxml_node_t *node)		// I - Node
        // Nothing to do
         break;
     case MXML_TYPE_OPAQUE :
-	free(node->value.opaque);
+	_mxml_strfree(node->value.opaque);
         break;
     case MXML_TYPE_REAL :
        // Nothing to do
         break;
     case MXML_TYPE_TEXT :
-	free(node->value.text.string);
+	_mxml_strfree(node->value.text.string);
         break;
     case MXML_TYPE_CUSTOM :
         if (node->value.custom.data && node->value.custom.destroy)

mxml-private.c

@@ -39,6 +39,184 @@
 #endif // __sun
 
 
+//
+// 'mxmlSetCustomHandlers()' - Set the custom data callbacks.
+//
+// This function sets the callbacks that are used for loading and saving custom
+// data types. The load callback `load_cb` accepts the callback data pointer
+// `cbdata`, a node pointer, and a data string and returns `true` on success and
+// `false` on error, for example:
+//
+// ```c
+// typedef struct
+// {
+//   unsigned year,    /* Year */
+//            month,   /* Month */
+//            day,     /* Day */
+//            hour,    /* Hour */
+//            minute,  /* Minute */
+//            second;  /* Second */
+//   time_t   unix;    /* UNIX time */
+// } iso_date_time_t;
+//
+// bool
+// my_custom_load_cb(void *cbdata, mxml_node_t *node, const char *data)
+// {
+//   iso_date_time_t *dt;
+//   struct tm tmdata;
+//
+//   /* Allocate custom data structure ... */
+//   dt = calloc(1, sizeof(iso_date_time_t));
+//
+//   /* Parse the data string... */
+//   if (sscanf(data, "%u-%u-%uT%u:%u:%uZ", &(dt->year), &(dt->month),
+//              &(dt->day), &(dt->hour), &(dt->minute), &(dt->second)) != 6)
+//   {
+//     /* Unable to parse date and time numbers... */
+//     free(dt);
+//     return (false);
+//   }
+//
+//   /* Range check values... */
+//   if (dt->month < 1 || dt->month > 12 || dt->day < 1 || dt->day > 31 ||
+//       dt->hour < 0 || dt->hour > 23 || dt->minute < 0 || dt->minute > 59 ||
+//       dt->second < 0 || dt->second > 60)
+//   {
+//     /* Date information is out of range... */
+//     free(dt);
+//     return (false);
+//   }
+//
+//   /* Convert ISO time to UNIX time in seconds... */
+//   tmdata.tm_year = dt->year - 1900;
+//   tmdata.tm_mon  = dt->month - 1;
+//   tmdata.tm_day  = dt->day;
+//   tmdata.tm_hour = dt->hour;
+//   tmdata.tm_min  = dt->minute;
+//   tmdata.tm_sec  = dt->second;
+//
+//   dt->unix = gmtime(&tmdata);
+//
+//   /* Set custom data and free function... */
+//   mxmlSetCustom(node, data, free);
+//
+//   /* Return with no errors... */
+//   return (true);
+// }
+// ```
+//
+// The save callback `save_cb` accepts the callback data pointer `cbdata` and a
+// node pointer and returns a malloc'd string on success and `NULL` on error,
+// for example:
+//
+// ```c
+// char *
+// my_custom_save_cb(void *cbdata, mxml_node_t *node)
+// {
+//   char data[255];
+//   iso_date_time_t *dt;
+//
+//   /* Get the custom data structure */
+//   dt = (iso_date_time_t *)mxmlGetCustom(node);
+//
+//   /* Generate string version of the date/time... */
+//   snprintf(data, sizeof(data), "%04u-%02u-%02uT%02u:%02u:%02uZ",
+//            dt->year, dt->month, dt->day, dt->hour, dt->minute, dt->second);
+//
+//   /* Duplicate the string and return... */
+//   return (strdup(data));
+// }
+// ```
+//
+
+
+void
+mxmlSetCustomCallbacks(
+    mxml_custom_load_cb_t load_cb,	// I - Load callback function
+    mxml_custom_save_cb_t save_cb,	// I - Save callback function
+    void                  *cbdata)	// I - Callback data
+{
+  _mxml_global_t *global = _mxml_global();
+					// Global data
+
+
+  global->custom_load_cb = load_cb;
+  global->custom_save_cb = save_cb;
+  global->custom_cbdata  = cbdata;
+}
+
+
+//
+// 'mxmlSetErrorCallback()' - Set the error message callback.
+//
+// This function sets a function to use when reporting errors.  The callback
+// `cb` accepts the data pointer `cbdata` and a string pointer containing the
+// error message:
+//
+// ```c
+// void my_error_cb(void *cbdata, const char *message)
+// {
+//   fprintf(stderr, "myprogram: %s\n", message);
+// }
+// ```
+//
+// The default error callback writes the error message to the `stderr` file.
+//
+
+void
+mxmlSetErrorCallback(
+    mxml_error_cb_t cb,			// I - Error callback function
+    void            *cbdata)		// I - Error callback data
+{
+  _mxml_global_t *global = _mxml_global();
+					// Global data
+
+
+  global->error_cb     = cb;
+  global->error_cbdata = cbdata;
+}
+
+
+//
+// 'mxmlSetStringCallbacks()' - Set the string copy/free callback functions.
+//
+// This function sets the string copy/free callback functions for the current
+// thread.  The `strcopy_cb` function makes a copy of the provided string while
+// the `strfree_cb` function frees the copy.  Each callback accepts the
+// `str_cbdata` pointer along with the pointer to the string:
+//
+// ```c
+// char *my_strcopy_cb(void *cbdata, const char *s)
+// {
+//   ... make a copy of "s" ...
+// }
+//
+// void my_strfree_cb(void *cbdata, char *s)
+// {
+//   ... release the memory used by "s" ...
+// }
+// ```
+//
+// The default `strcopy_cb` function calls `strdup` while the default
+// `strfree_cb` function calls `free`.
+//
+
+void
+mxmlSetStringCallbacks(
+    mxml_strcopy_cb_t strcopy_cb,	// I - String copy callback function
+    mxml_strfree_cb_t strfree_cb,	// I - String free callback function
+    void              *str_cbdata)	// I - String callback data
+{
+  _mxml_global_t *global = _mxml_global();
+					// Global data
+
+
+  global->strcopy_cb = strcopy_cb;
+  global->strfree_cb = strfree_cb;
+  global->str_cbdata = str_cbdata;
+}
+
+
 //
 // '_mxml_error()' - Display an error message.
 //
@@ -70,6 +248,48 @@ _mxml_error(const char *format,		// I - Printf-style format string
 }
 
 
+//
+// '_mxml_strcopy()' - Copy a string.
+//
+
+char *					// O - Copy of string
+_mxml_strcopy(const char *s)		// I - String
+{
+  _mxml_global_t *global = _mxml_global();
+					// Global data
+
+
+  if (!s)
+    return (NULL);
+
+  if (global->strcopy_cb)
+    return ((global->strcopy_cb)(global->str_cbdata, s));
+  else
+    return (strdup(s));
+}
+
+
+//
+// '_mxml_strfree()' - Free a string.
+//
+
+void
+_mxml_strfree(char *s)			// I - String
+{
+  _mxml_global_t *global = _mxml_global();
+					// Global data
+
+
+  if (!s)
+    return;
+
+  if (global->strfree_cb)
+    (global->strfree_cb)(global->str_cbdata, s);
+  else
+    free((void *)s);
+}
+
+
 #ifdef HAVE_PTHREAD_H			// POSIX threading
 #  include <pthread.h>
 

mxml-private.h

@@ -107,6 +107,9 @@ typedef struct _mxml_global_s		// Global, per-thread data
   struct lconv	*loc;			// Locale data
   size_t	loc_declen;		// Length of decimal point string
   bool		loc_set;		// Locale data set?
+  mxml_strcopy_cb_t strcopy_cb;		// String copy callback function
+  mxml_strfree_cb_t strfree_cb;		// String free callback function
+  void		*str_cbdata;		// String callback data
   int		wrap;			// Wrap margin
 } _mxml_global_t;
 
@@ -119,6 +122,7 @@ extern _mxml_global_t	*_mxml_global(void);
 extern int		_mxml_entity_cb(void *cbdata, const char *name);
 extern const char	*_mxml_entity_string(int ch);
 extern void		_mxml_error(const char *format, ...) MXML_FORMAT(1,2);
-
+extern char		*_mxml_strcopy(const char *s);
+extern void		_mxml_strfree(char *s);
 
 #endif // !MXML_PRIVATE_H

mxml-set.c

@@ -47,13 +47,13 @@ mxmlSetCDATA(mxml_node_t *node,		// I - Node to set
   }
 
   // Allocate the new value, free any old element value, and set the new value...
-  if ((s = strdup(data)) == NULL)
+  if ((s = _mxml_strcopy(data)) == NULL)
   {
     _mxml_error("Unable to allocate memory for CDATA.");
     return (false);
   }
 
-  free(node->value.cdata);
+  _mxml_strfree(node->value.cdata);
   node->value.cdata = s;
 
   return (true);
@@ -94,13 +94,13 @@ mxmlSetCDATAf(mxml_node_t *node,	// I - Node
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for CDATA string.");
     return (false);
   }
 
-  free(node->value.cdata);
+  _mxml_strfree(node->value.cdata);
   node->value.cdata = s;
 
   return (true);
@@ -137,13 +137,13 @@ mxmlSetComment(mxml_node_t *node,	// I - Node
     return (true);
 
   // Free any old string value and set the new value...
-  if ((s = strdup(comment)) == NULL)
+  if ((s = _mxml_strcopy(comment)) == NULL)
   {
     _mxml_error("Unable to allocate memory for comment string.");
     return (false);
   }
 
-  free(node->value.comment);
+  _mxml_strfree(node->value.comment);
   node->value.comment = s;
 
   return (true);
@@ -184,13 +184,13 @@ mxmlSetCommentf(mxml_node_t *node,	// I - Node
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for comment string.");
     return (false);
   }
 
-  free(node->value.comment);
+  _mxml_strfree(node->value.comment);
   node->value.comment = s;
 
   return (true);
@@ -267,13 +267,13 @@ mxmlSetDeclaration(
     return (true);
 
   // Free any old string value and set the new value...
-  if ((s = strdup(declaration)) == NULL)
+  if ((s = _mxml_strcopy(declaration)) == NULL)
   {
     _mxml_error("Unable to allocate memory for declaration string.");
     return (false);
   }
 
-  free(node->value.declaration);
+  _mxml_strfree(node->value.declaration);
   node->value.declaration = s;
 
   return (true);
@@ -314,13 +314,13 @@ mxmlSetDeclarationf(mxml_node_t *node,	// I - Node
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for declaration string.");
     return (false);
   }
 
-  free(node->value.declaration);
+  _mxml_strfree(node->value.declaration);
   node->value.declaration = s;
 
   return (true);
@@ -357,13 +357,13 @@ mxmlSetDirective(mxml_node_t *node,	// I - Node
     return (true);
 
   // Free any old string value and set the new value...
-  if ((s = strdup(directive)) == NULL)
+  if ((s = _mxml_strcopy(directive)) == NULL)
   {
     _mxml_error("Unable to allocate memory for directive string.");
     return (false);
   }
 
-  free(node->value.directive);
+  _mxml_strfree(node->value.directive);
   node->value.directive = s;
 
   return (true);
@@ -404,13 +404,13 @@ mxmlSetDirectivef(mxml_node_t *node,	// I - Node
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for directive string.");
     return (false);
   }
 
-  free(node->value.directive);
+  _mxml_strfree(node->value.directive);
   node->value.directive = s;
 
   return (true);
@@ -446,13 +446,13 @@ mxmlSetElement(mxml_node_t *node,	// I - Node to set
     return (true);
 
   // Free any old element value and set the new value...
-  if ((s = strdup(name)) == NULL)
+  if ((s = _mxml_strcopy(name)) == NULL)
   {
     _mxml_error("Unable to allocate memory for element name.");
     return (false);
   }
 
-  free(node->value.element.name);
+  _mxml_strfree(node->value.element.name);
   node->value.element.name = s;
 
   return (true);
@@ -518,13 +518,13 @@ mxmlSetOpaque(mxml_node_t *node,	// I - Node to set
     return (true);
 
   // Free any old opaque value and set the new value...
-  if ((s = strdup(opaque)) == NULL)
+  if ((s = _mxml_strcopy(opaque)) == NULL)
   {
     _mxml_error("Unable to allocate memory for opaque string.");
     return (false);
   }
 
-  free(node->value.opaque);
+  _mxml_strfree(node->value.opaque);
   node->value.opaque = s;
 
   return (true);
@@ -567,13 +567,13 @@ mxmlSetOpaquef(mxml_node_t *node,	// I - Node to set
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for opaque string.");
     return (false);
   }
 
-  free(node->value.opaque);
+  _mxml_strfree(node->value.opaque);
   node->value.opaque = s;
 
   return (true);
@@ -646,13 +646,13 @@ mxmlSetText(mxml_node_t *node,		// I - Node to set
   }
 
   // Free any old string value and set the new value...
-  if ((s = strdup(string)) == NULL)
+  if ((s = _mxml_strcopy(string)) == NULL)
   {
     _mxml_error("Unable to allocate memory for text string.");
     return (false);
   }
 
-  free(node->value.text.string);
+  _mxml_strfree(node->value.text.string);
 
   node->value.text.whitespace = whitespace;
   node->value.text.string     = s;
@@ -698,13 +698,13 @@ mxmlSetTextf(mxml_node_t *node,		// I - Node to set
   vsnprintf(buffer, sizeof(buffer), format, ap);
   va_end(ap);
 
-  if ((s = strdup(buffer)) == NULL)
+  if ((s = _mxml_strcopy(buffer)) == NULL)
   {
     _mxml_error("Unable to allocate memory for text string.");
     return (false);
   }
 
-  free(node->value.text.string);
+  _mxml_strfree(node->value.text.string);
 
   node->value.text.whitespace = whitespace;
   node->value.text.string     = s;

mxml.h

@@ -124,6 +124,11 @@ typedef ssize_t (*mxml_read_cb_t)(void *cbdata, void *buffer, size_t bytes);
 typedef const char *(*mxml_save_cb_t)(void *cbdata, mxml_node_t *node, mxml_ws_t when);
 					// Save callback function
 
+typedef char *(*mxml_strcopy_cb_t)(void *cbdata, const char *s);
+					// String copy/allocation callback
+typedef void (*mxml_strfree_cb_t)(void *cbdata, char *s);
+					// String free callback
+
 typedef ssize_t (*mxml_write_cb_t)(void *cbdata, const void *buffer, size_t bytes);
 					// Write callback function
 
@@ -220,7 +225,7 @@ extern bool		mxmlSetDeclaration(mxml_node_t *node, const char *declaration);
 extern bool		mxmlSetDeclarationf(mxml_node_t *node, const char *format, ...) MXML_FORMAT(2,3);
 extern bool		mxmlSetDirective(mxml_node_t *node, const char *directive);
 extern bool		mxmlSetDirectivef(mxml_node_t *node, const char *format, ...) MXML_FORMAT(2,3);
-extern bool		mxmlSetCustom(mxml_node_t *node, void *data, mxml_custom_destroy_cb_t destroy);
+extern bool		mxmlSetCustom(mxml_node_t *node, void *data, mxml_custom_destroy_cb_t destroy_cb);
 extern void		mxmlSetCustomCallbacks(mxml_custom_load_cb_t load_cb, mxml_custom_save_cb_t save_cb, void *cbdata);
 extern bool		mxmlSetElement(mxml_node_t *node, const char *name);
 extern void		mxmlSetErrorCallback(mxml_error_cb_t cb, void *cbdata);
@@ -228,6 +233,7 @@ extern bool		mxmlSetInteger(mxml_node_t *node, long integer);
 extern bool		mxmlSetOpaque(mxml_node_t *node, const char *opaque);
 extern bool		mxmlSetOpaquef(mxml_node_t *node, const char *format, ...) MXML_FORMAT(2,3);
 extern bool		mxmlSetReal(mxml_node_t *node, double real);
+extern void		mxmlSetStringCallbacks(mxml_strcopy_cb_t strcopy_cb, mxml_strfree_cb_t strfree_cb, void *str_cbdata);
 extern bool		mxmlSetText(mxml_node_t *node, bool whitespace, const char *string);
 extern bool		mxmlSetTextf(mxml_node_t *node, bool whitespace, const char *format, ...) MXML_FORMAT(3,4);
 extern bool		mxmlSetUserData(mxml_node_t *node, void *data);