File bug-1024037_pacemaker-libcrmcommon-compare-XML-comments.patch of Package pacemaker.14737

commit c509cd07008b1f9b3402eeb7d7f3f6d504aa4fdb
Author: Gao,Yan <ygao@suse.com>
Date:   Fri Feb 10 15:44:16 2017 +0100

    Fix: libcrmcommon: Correctly compare XML comments to prevent crmd from getting into infinite election loop
    
    With b7fa323, crmd could still get into an infinite election loop when
    there was more than one comment with the exactly same text at the same
    level within a CIB XML element. For example:
    
    '''
      <!--# "Fri Feb 10 11:20:40 CET 2017-->
      <!--#============================================================================-->
      <!--#-->
      <!--# Administrator A-->
      <!--#-->
      <!--# Pacemaker basic config file for Cluster A-->
      <!--#============================================================================-->
      <!--#-->
    '''
    
    Basically, it'd produce big messes if using the diff operation "move"
    for XML comments in such a case.
    
    With this commit, it strictly tries to match the XML comments at the
    exactly same offsets when comparing v2 patchset, so that only the diff
    operations "create" and "delete" will be used for XML comments.

Index: pacemaker/lib/common/xml.c
===================================================================
--- pacemaker.orig/lib/common/xml.c
+++ pacemaker/lib/common/xml.c
@@ -142,7 +142,7 @@ static struct schema_s *known_schemas =
 static int xml_schema_max = 0;
 
 static xmlNode *subtract_xml_comment(xmlNode * parent, xmlNode * left, xmlNode * right, gboolean * changed);
-static xmlNode *find_xml_comment(xmlNode * root, xmlNode * search_comment);
+static xmlNode *find_xml_comment(xmlNode * root, xmlNode * search_comment, gboolean exact);
 static int add_xml_comment(xmlNode * parent, xmlNode * target, xmlNode * update);
 static bool __xml_acl_check(xmlNode *xml, const char *name, enum xml_private_flags mode);
 const char *__xml_acl_to_text(enum xml_private_flags flags);
@@ -1815,11 +1815,11 @@ xml_accept_changes(xmlNode * xml)
 }
 
 static xmlNode *
-find_element(xmlNode *haystack, xmlNode *needle)
+find_element(xmlNode *haystack, xmlNode *needle, gboolean exact)
 {
     CRM_CHECK(needle != NULL, return NULL);
     return (needle->type == XML_COMMENT_NODE)?
-           find_xml_comment(haystack, needle)
+           find_xml_comment(haystack, needle, exact)
            : find_entity(haystack, crm_element_name(needle), ID(needle));
 }
 
@@ -1875,7 +1875,7 @@ __subtract_xml_object(xmlNode * target,
         xmlNode *target_child = cIter;
 
         cIter = __xml_next(cIter);
-        patch_child = find_element(patch, target_child);
+        patch_child = find_element(patch, target_child, FALSE);
         __subtract_xml_object(target_child, patch_child);
     }
     free(id);
@@ -1937,7 +1937,7 @@ __add_xml_object(xmlNode * parent, xmlNo
     for (patch_child = __xml_first_child(patch); patch_child != NULL;
          patch_child = __xml_next(patch_child)) {
 
-        target_child = find_element(target, patch_child);
+        target_child = find_element(target, patch_child, FALSE);
         __add_xml_object(target, target_child, patch_child);
     }
 }
@@ -4284,7 +4284,7 @@ __xml_diff_object(xmlNode * old, xmlNode
 
     for (cIter = __xml_first_child(old); cIter != NULL; ) {
         xmlNode *old_child = cIter;
-        xmlNode *new_child = find_element(new, cIter);
+        xmlNode *new_child = find_element(new, cIter, TRUE);
 
         cIter = __xml_next(cIter);
         if(new_child) {
@@ -4299,7 +4299,7 @@ __xml_diff_object(xmlNode * old, xmlNode
             __xml_acl_apply(top); /* Make sure any ACLs are applied to 'candidate' */
             free_xml(candidate);
 
-            if (find_element(new, old_child) == NULL) {
+            if (find_element(new, old_child, TRUE) == NULL) {
                 xml_private_t *p = old_child->_private;
 
                 p->flags |= xpf_skip;
@@ -4309,7 +4309,7 @@ __xml_diff_object(xmlNode * old, xmlNode
 
     for (cIter = __xml_first_child(new); cIter != NULL; ) {
         xmlNode *new_child = cIter;
-        xmlNode *old_child = find_element(old, cIter);
+        xmlNode *old_child = find_element(old, cIter, TRUE);
 
         cIter = __xml_next(cIter);
         if(old_child == NULL) {
@@ -4484,18 +4484,36 @@ in_upper_context(int depth, int context,
 }
 
 static xmlNode *
-find_xml_comment(xmlNode * root, xmlNode * search_comment)
+find_xml_comment(xmlNode * root, xmlNode * search_comment, gboolean exact)
 {
     xmlNode *a_child = NULL;
+    int search_offset = __xml_offset(search_comment);
 
     CRM_CHECK(search_comment->type == XML_COMMENT_NODE, return NULL);
 
     for (a_child = __xml_first_child(root); a_child != NULL; a_child = __xml_next(a_child)) {
-        if (a_child->type != XML_COMMENT_NODE) {
-            continue;
+        if (exact) {
+            int offset = __xml_offset(a_child);
+            xml_private_t *p = a_child->_private;
+
+            if (offset < search_offset) {
+                continue;
+
+            } else if (offset > search_offset) {
+                return NULL;
+            }
+
+            if (is_set(p->flags, xpf_skip)) {
+                continue;
+            }
         }
-        if (safe_str_eq((const char *)a_child->content, (const char *)search_comment->content)) {
+
+        if (a_child->type == XML_COMMENT_NODE
+            && safe_str_eq((const char *)a_child->content, (const char *)search_comment->content)) {
             return a_child;
+
+        } else if (exact) {
+            return NULL;
         }
     }
 
@@ -4590,7 +4608,7 @@ subtract_xml_object(xmlNode * parent, xm
          left_child = __xml_next(left_child)) {
         gboolean child_changed = FALSE;
 
-        right_child = find_element(right, left_child);
+        right_child = find_element(right, left_child, FALSE);
         subtract_xml_object(diff, left_child, right_child, full, &child_changed, marker);
         if (child_changed) {
             *changed = TRUE;
@@ -4716,7 +4734,7 @@ add_xml_comment(xmlNode * parent, xmlNod
     CRM_CHECK(update->type == XML_COMMENT_NODE, return 0);
 
     if (target == NULL) {
-        target = find_xml_comment(parent, update);
+        target = find_xml_comment(parent, update, FALSE);
     }
 
     if (target == NULL) {