This patch modifies the NWFilter parameter parser to support multiple
elements with the same name and to internally build a list of items.
An example of the XML looks like this:

        <parameter name='TEST' value='10.1.2.3'/>
        <parameter name='TEST' value='10.2.3.4'/>
        <parameter name='TEST' value='10.1.1.1'/>

The list of values is then stored in the newly introduced data type
virNWFilterVarValue.

The XML formatter is also adapted to print out all items in alphabetical
order sorted by 'name'.

This patch als fixes a bug in the XML schema on the way.

v4:
 - schema: removed the <optional> node in favor of the <zeroOrMore> node

v3:
 - Follow Daniel Berrange's suggestion of parsing a list as shown above
 - Rewrote XML formatter to print out parameters in alphabetical order

v2:
 - check that each item in the list only contains allowed characters

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

---
 docs/schemas/nwfilter.rng  |    4 +-
 src/conf/nwfilter_params.c |   86 ++++++++++++++++++++++++++++-----------------
 2 files changed, 56 insertions(+), 34 deletions(-)

Index: libvirt-acl/src/conf/nwfilter_params.c
===================================================================
--- libvirt-acl.orig/src/conf/nwfilter_params.c
+++ libvirt-acl/src/conf/nwfilter_params.c
@@ -674,7 +674,7 @@ isValidVarName(const char *var)
 static bool
 isValidVarValue(const char *value)
 {
-    return value[strspn(value, VALID_VARVALUE)] == 0;
+    return (value[strspn(value, VALID_VARVALUE)] == 0) && (strlen(value) != 0);
 }
 
 static virNWFilterVarValuePtr
@@ -706,15 +706,22 @@ virNWFilterParseParamAttributes(xmlNodeP
                 if (nam != NULL && val != NULL) {
                     if (!isValidVarName(nam))
                         goto skip_entry;
-                    value = virNWFilterParseVarValue(val);
-                    if (!value)
+                    if (!isValidVarValue(val))
                         goto skip_entry;
-                    if (virNWFilterHashTablePut(table, nam, value, 1)) {
-                        VIR_FREE(nam);
-                        VIR_FREE(val);
-                        virNWFilterVarValueFree(value);
-                        virNWFilterHashTableFree(table);
-                        return NULL;
+                    value = virHashLookup(table->hashTable, nam);
+                    if (value) {
+                        /* add value to existing value -> list */
+                        if (!virNWFilterVarValueAddValue(value, val, false)) {
+                            value = NULL;
+                            goto err_exit;
+                        }
+                        val = NULL;
+                    } else {
+                        value = virNWFilterParseVarValue(val);
+                        if (!value)
+                            goto skip_entry;
+                        if (virNWFilterHashTablePut(table, nam, value, 1))
+                            goto err_exit;
                     }
                     value = NULL;
                 }
@@ -727,40 +734,55 @@ skip_entry:
         cur = cur->next;
     }
     return table;
-}
-
-
-struct formatterParam {
-    virBufferPtr buf;
-    const char *indent;
-};
 
+err_exit:
+    VIR_FREE(nam);
+    VIR_FREE(val);
+    virNWFilterVarValueFree(value);
+    virNWFilterHashTableFree(table);
+    return NULL;
+}
 
-static void
-_formatParameterAttrs(void *payload, const void *name, void *data)
+static int
+virNWFilterFormatParameterNameSorter(const virHashKeyValuePairPtr a,
+                                     const virHashKeyValuePairPtr b)
 {
-    struct formatterParam *fp = (struct formatterParam *)data;
-    virNWFilterVarValuePtr value = payload;
-
-    virBufferAsprintf(fp->buf, "%s<parameter name='%s' value='",
-                      fp->indent,
-                      (const char *)name);
-    virNWFilterVarValuePrint(value, fp->buf);
-    virBufferAddLit(fp->buf, "'/>\n");
+    return strcmp((const char *)a->key, (const char *)b->key);
 }
 
-
 char *
 virNWFilterFormatParamAttributes(virNWFilterHashTablePtr table,
                                  const char *indent)
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
-    struct formatterParam fp = {
-        .buf = &buf,
-        .indent = indent,
-    };
+    char **keys, *key;
+    int i, j, card, numKeys;
+    virNWFilterVarValuePtr value;
+
+    if (!table)
+        return NULL;
+
+    keys = (char **)virHashGetKeys(table->hashTable,
+                                   virNWFilterFormatParameterNameSorter);
+    if (!keys)
+        return NULL;
+
+    numKeys = virHashSize(table->hashTable);
+
+    for (i = 0; i < numKeys; i++) {
+        value = virHashLookup(table->hashTable, keys[i]);
+        card = virNWFilterVarValueGetCardinality(value);
+
+        for (j = 0; j < card; j++) {
+            virBufferAsprintf(&buf,
+                              "%s<parameter name='%s' value='%s'/>\n",
+                              indent, keys[i],
+                              virNWFilterVarValueGetNthValue(value, j));
+        }
+        key = keys[i];
+    }
 
-    virHashForEach(table->hashTable, _formatParameterAttrs, &fp);
+    virHashFreeKeys(table->hashTable, (void **)keys);
 
     if (virBufferError(&buf)) {
         virReportOOMError();
Index: libvirt-acl/docs/schemas/nwfilter.rng
===================================================================
--- libvirt-acl.orig/docs/schemas/nwfilter.rng
+++ libvirt-acl/docs/schemas/nwfilter.rng
@@ -312,7 +312,7 @@
     <attribute name="filter">
       <data type="NCName"/>
     </attribute>
-    <optional>
+    <zeroOrMore>
       <element name="parameter">
         <attribute name="name">
           <ref name="filter-param-name"/>
@@ -321,7 +321,7 @@
           <ref name="filter-param-value"/>
         </attribute>
       </element>
-    </optional>
+    </zeroOrMore>
   </define>
 
   <define name="rule-node-attributes">