xml.c

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/*
 * Copyright 2004-2021 the Pacemaker project contributors
 *
 * The version control history for this file may have further details.
 *
 * This source code is licensed under the GNU Lesser General Public License
 * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
 */

#include <crm_internal.h>

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <bzlib.h>

#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xmlIO.h>  /* xmlAllocOutputBuffer */

#include <crm/crm.h>
#include <crm/msg_xml.h>
#include <crm/common/iso8601_internal.h>
#include <crm/common/xml.h>
#include <crm/common/xml_internal.h>  // PCMK__XML_LOG_BASE, etc.
#include "crmcommon_private.h"

// Define this as 1 in development to get insanely verbose trace messages
#ifndef XML_PARSER_DEBUG
#define XML_PARSER_DEBUG 0
#endif


/* @TODO XML_PARSE_RECOVER allows some XML errors to be silently worked around
 * by libxml2, which is potentially ambiguous and dangerous. We should drop it
 * when we can break backward compatibility with configurations that might be
 * relying on it (i.e. pacemaker 3.0.0).
 *
 * It might be a good idea to have a transitional period where we first try
 * parsing without XML_PARSE_RECOVER, and if that fails, try parsing again with
 * it, logging a warning if it succeeds.
 */
#define PCMK__XML_PARSE_OPTS    (XML_PARSE_NOBLANKS | XML_PARSE_RECOVER)

#define CHUNK_SIZE 1024

bool
pcmk__tracking_xml_changes(xmlNode *xml, bool lazy)
{
    if(xml == NULL || xml->doc == NULL || xml->doc->_private == NULL) {
        return FALSE;
    } else if (!pcmk_is_set(((xml_private_t *)xml->doc->_private)->flags,
                            xpf_tracking)) {
        return FALSE;
    } else if (lazy && !pcmk_is_set(((xml_private_t *)xml->doc->_private)->flags,
                                    xpf_lazy)) {
        return FALSE;
    }
    return TRUE;
}

#define buffer_print(buffer, max, offset, fmt, args...) do {            \
        int rc = (max);                                                 \
        if(buffer) {                                                    \
            rc = snprintf((buffer) + (offset), (max) - (offset), fmt, ##args); \
        }                                                               \
        if(buffer && rc < 0) {                                          \
            crm_perror(LOG_ERR, "snprintf failed at offset %d", offset); \
            (buffer)[(offset)] = 0;                                     \
            break;                                                      \
        } else if(rc >= ((max) - (offset))) {                           \
            char *tmp = NULL;                                           \
            (max) = QB_MAX(CHUNK_SIZE, (max) * 2);                      \
            tmp = pcmk__realloc((buffer), (max));                       \
            CRM_ASSERT(tmp);                                            \
            (buffer) = tmp;                                             \
        } else {                                                        \
            offset += rc;                                               \
            break;                                                      \
        }                                                               \
    } while(1);

static void
insert_prefix(int options, char **buffer, int *offset, int *max, int depth)
{
    if (options & xml_log_option_formatted) {
        size_t spaces = 2 * depth;

        if ((*buffer) == NULL || spaces >= ((*max) - (*offset))) {
            (*max) = QB_MAX(CHUNK_SIZE, (*max) * 2);
            (*buffer) = pcmk__realloc((*buffer), (*max));
        }
        memset((*buffer) + (*offset), ' ', spaces);
        (*offset) += spaces;
    }
}

static void
set_parent_flag(xmlNode *xml, long flag) 
{

    for(; xml; xml = xml->parent) {
        xml_private_t *p = xml->_private;

        if(p == NULL) {
            /* During calls to xmlDocCopyNode(), _private will be unset for parent nodes */
        } else {
            pcmk__set_xml_flags(p, flag);
        }
    }
}

void
pcmk__set_xml_doc_flag(xmlNode *xml, enum xml_private_flags flag)
{

    if(xml && xml->doc && xml->doc->_private){
        /* During calls to xmlDocCopyNode(), xml->doc may be unset */
        xml_private_t *p = xml->doc->_private;

        pcmk__set_xml_flags(p, flag);
    }
}

// Mark document, element, and all element's parents as changed
static void
mark_xml_node_dirty(xmlNode *xml)
{
    pcmk__set_xml_doc_flag(xml, xpf_dirty);
    set_parent_flag(xml, xpf_dirty);
}

// Clear flags on XML node and its children
static void
reset_xml_node_flags(xmlNode *xml)
{
    xmlNode *cIter = NULL;
    xml_private_t *p = xml->_private;

    if (p) {
        p->flags = 0;
    }

    for (cIter = pcmk__xml_first_child(xml); cIter != NULL;
         cIter = pcmk__xml_next(cIter)) {
        reset_xml_node_flags(cIter);
    }
}

// Set xpf_created flag on XML node and any children
void
pcmk__mark_xml_created(xmlNode *xml)
{
    xmlNode *cIter = NULL;
    xml_private_t *p = xml->_private;

    if (p && pcmk__tracking_xml_changes(xml, FALSE)) {
        if (!pcmk_is_set(p->flags, xpf_created)) {
            pcmk__set_xml_flags(p, xpf_created);
            mark_xml_node_dirty(xml);
        }
        for (cIter = pcmk__xml_first_child(xml); cIter != NULL;
             cIter = pcmk__xml_next(cIter)) {
            pcmk__mark_xml_created(cIter);
        }
    }
}

void
pcmk__mark_xml_attr_dirty(xmlAttr *a) 
{
    xmlNode *parent = a->parent;
    xml_private_t *p = NULL;

    p = a->_private;
    pcmk__set_xml_flags(p, xpf_dirty|xpf_modified);
    pcmk__clear_xml_flags(p, xpf_deleted);
    mark_xml_node_dirty(parent);
}

#define XML_PRIVATE_MAGIC (long) 0x81726354

// Free an XML object previously marked as deleted
static void
free_deleted_object(void *data)
{
    if(data) {
        pcmk__deleted_xml_t *deleted_obj = data;

        free(deleted_obj->path);
        free(deleted_obj);
    }
}

// Free and NULL user, ACLs, and deleted objects in an XML node's private data
static void
reset_xml_private_data(xml_private_t *p)
{
    if(p) {
        CRM_ASSERT(p->check == XML_PRIVATE_MAGIC);

        free(p->user);
        p->user = NULL;

        if(p->acls) {
            pcmk__free_acls(p->acls);
            p->acls = NULL;
        }

        if(p->deleted_objs) {
            g_list_free_full(p->deleted_objs, free_deleted_object);
            p->deleted_objs = NULL;
        }
    }
}

// Free all private data associated with an XML node
static void
free_private_data(xmlNode *node)
{
    /* need to explicitly avoid our custom _private field cleanup when
       called from internal XSLT cleanup (xsltApplyStylesheetInternal
       -> xsltFreeTransformContext -> xsltFreeRVTs -> xmlFreeDoc)
       onto result tree fragments, represented as standalone documents
       with otherwise infeasible space-prefixed name (xsltInternals.h:
       XSLT_MARK_RES_TREE_FRAG) and carrying it's own load at _private
       field -- later assert on the XML_PRIVATE_MAGIC would explode */
    if (node->type != XML_DOCUMENT_NODE || node->name == NULL
            || node->name[0] != ' ') {
        reset_xml_private_data(node->_private);
        free(node->_private);
    }
}

// Allocate and initialize private data for an XML node
static void
new_private_data(xmlNode *node)
{
    xml_private_t *p = NULL;

    switch(node->type) {
        case XML_ELEMENT_NODE:
        case XML_DOCUMENT_NODE:
        case XML_ATTRIBUTE_NODE:
        case XML_COMMENT_NODE:
            p = calloc(1, sizeof(xml_private_t));
            p->check = XML_PRIVATE_MAGIC;
            /* Flags will be reset if necessary when tracking is enabled */
            pcmk__set_xml_flags(p, xpf_dirty|xpf_created);
            node->_private = p;
            break;
        case XML_TEXT_NODE:
        case XML_DTD_NODE:
        case XML_CDATA_SECTION_NODE:
            break;
        default:
            /* Ignore */
            crm_trace("Ignoring %p %d", node, node->type);
            CRM_LOG_ASSERT(node->type == XML_ELEMENT_NODE);
            break;
    }

    if(p && pcmk__tracking_xml_changes(node, FALSE)) {
        /* XML_ELEMENT_NODE doesn't get picked up here, node->doc is
         * not hooked up at the point we are called
         */
        mark_xml_node_dirty(node);
    }
}

void
xml_track_changes(xmlNode * xml, const char *user, xmlNode *acl_source, bool enforce_acls) 
{
    xml_accept_changes(xml);
    crm_trace("Tracking changes%s to %p", enforce_acls?" with ACLs":"", xml);
    pcmk__set_xml_doc_flag(xml, xpf_tracking);
    if(enforce_acls) {
        if(acl_source == NULL) {
            acl_source = xml;
        }
        pcmk__set_xml_doc_flag(xml, xpf_acl_enabled);
        pcmk__unpack_acl(acl_source, xml, user);
        pcmk__apply_acl(xml);
    }
}

bool xml_tracking_changes(xmlNode * xml)
{
    return (xml != NULL) && (xml->doc != NULL) && (xml->doc->_private != NULL)
           && pcmk_is_set(((xml_private_t *)(xml->doc->_private))->flags,
                          xpf_tracking);
}

bool xml_document_dirty(xmlNode *xml) 
{
    return (xml != NULL) && (xml->doc != NULL) && (xml->doc->_private != NULL)
           && pcmk_is_set(((xml_private_t *)(xml->doc->_private))->flags,
                          xpf_dirty);
}

int
pcmk__xml_position(xmlNode *xml, enum xml_private_flags ignore_if_set)
{
    int position = 0;
    xmlNode *cIter = NULL;

    for(cIter = xml; cIter->prev; cIter = cIter->prev) {
        xml_private_t *p = ((xmlNode*)cIter->prev)->_private;

        if (!pcmk_is_set(p->flags, ignore_if_set)) {
            position++;
        }
    }

    return position;
}

// This also clears attribute's flags if not marked as deleted
static bool
marked_as_deleted(xmlAttrPtr a, void *user_data)
{
    xml_private_t *p = a->_private;

    if (pcmk_is_set(p->flags, xpf_deleted)) {
        return true;
    }
    p->flags = xpf_none;
    return false;
}

// Remove all attributes marked as deleted from an XML node
static void
accept_attr_deletions(xmlNode *xml)
{
    // Clear XML node's flags
    ((xml_private_t *) xml->_private)->flags = xpf_none;

    // Remove this XML node's attributes that were marked as deleted
    pcmk__xe_remove_matching_attrs(xml, marked_as_deleted, NULL);

    // Recursively do the same for this XML node's children
    for (xmlNodePtr cIter = pcmk__xml_first_child(xml); cIter != NULL;
         cIter = pcmk__xml_next(cIter)) {
        accept_attr_deletions(cIter);
    }
}

xmlNode *
pcmk__xml_match(xmlNode *haystack, xmlNode *needle, bool exact)
{
    CRM_CHECK(needle != NULL, return NULL);

    if (needle->type == XML_COMMENT_NODE) {
        return pcmk__xc_match(haystack, needle, exact);

    } else {
        const char *id = ID(needle);
        const char *attr = (id == NULL)? NULL : XML_ATTR_ID;

        return pcmk__xe_match(haystack, crm_element_name(needle), attr, id);
    }
}

void
xml_log_changes(uint8_t log_level, const char *function, xmlNode * xml)
{
    GList *gIter = NULL;
    xml_private_t *doc = NULL;

    if (log_level == LOG_NEVER) {
        return;
    }

    CRM_ASSERT(xml);
    CRM_ASSERT(xml->doc);

    doc = xml->doc->_private;
    if (!pcmk_is_set(doc->flags, xpf_dirty)) {
        return;
    }

    for(gIter = doc->deleted_objs; gIter; gIter = gIter->next) {
        pcmk__deleted_xml_t *deleted_obj = gIter->data;

        if (deleted_obj->position >= 0) {
            do_crm_log_alias(log_level, __FILE__, function, __LINE__, "-- %s (%d)",
                             deleted_obj->path, deleted_obj->position);

        } else {
            do_crm_log_alias(log_level, __FILE__, function, __LINE__, "-- %s",
                             deleted_obj->path);
        }
    }

    log_data_element(log_level, __FILE__, function, __LINE__, "+ ", xml, 0,
                     xml_log_option_formatted|xml_log_option_dirty_add);
}

void
xml_accept_changes(xmlNode * xml)
{
    xmlNode *top = NULL;
    xml_private_t *doc = NULL;

    if(xml == NULL) {
        return;
    }

    crm_trace("Accepting changes to %p", xml);
    doc = xml->doc->_private;
    top = xmlDocGetRootElement(xml->doc);

    reset_xml_private_data(xml->doc->_private);

    if (!pcmk_is_set(doc->flags, xpf_dirty)) {
        doc->flags = xpf_none;
        return;
    }

    doc->flags = xpf_none;
    accept_attr_deletions(top);
}

xmlNode *
find_xml_node(xmlNode * root, const char *search_path, gboolean must_find)
{
    xmlNode *a_child = NULL;
    const char *name = "NULL";

    if (root != NULL) {
        name = crm_element_name(root);
    }

    if (search_path == NULL) {
        crm_warn("Will never find <NULL>");
        return NULL;
    }

    for (a_child = pcmk__xml_first_child(root); a_child != NULL;
         a_child = pcmk__xml_next(a_child)) {
        if (strcmp((const char *)a_child->name, search_path) == 0) {
/*      crm_trace("returning node (%s).", crm_element_name(a_child)); */
            return a_child;
        }
    }

    if (must_find) {
        crm_warn("Could not find %s in %s.", search_path, name);
    } else if (root != NULL) {
        crm_trace("Could not find %s in %s.", search_path, name);
    } else {
        crm_trace("Could not find %s in <NULL>.", search_path);
    }

    return NULL;
}

#define attr_matches(c, n, v) pcmk__str_eq(crm_element_value((c), (n)), \
                                           (v), pcmk__str_none)

xmlNode *
pcmk__xe_match(xmlNode *parent, const char *node_name,
               const char *attr_n, const char *attr_v)
{
    /* ensure attr_v specified when attr_n is */
    CRM_CHECK(attr_n == NULL || attr_v != NULL, return NULL);

    for (xmlNode *child = pcmk__xml_first_child(parent); child != NULL;
         child = pcmk__xml_next(child)) {
        if (pcmk__str_eq(node_name, (const char *) (child->name),
                         pcmk__str_null_matches)
            && ((attr_n == NULL) || attr_matches(child, attr_n, attr_v))) {
            return child;
        }
    }
    crm_trace("XML child node <%s%s%s%s%s> not found in %s",
              (node_name? node_name : "(any)"),
              (attr_n? " " : ""),
              (attr_n? attr_n : ""),
              (attr_n? "=" : ""),
              (attr_n? attr_v : ""),
              crm_element_name(parent));
    return NULL;
}

void
copy_in_properties(xmlNode * target, xmlNode * src)
{
    if (src == NULL) {
        crm_warn("No node to copy properties from");

    } else if (target == NULL) {
        crm_err("No node to copy properties into");

    } else {
        for (xmlAttrPtr a = pcmk__xe_first_attr(src); a != NULL; a = a->next) {
            const char *p_name = (const char *) a->name;
            const char *p_value = pcmk__xml_attr_value(a);

            expand_plus_plus(target, p_name, p_value);
        }
    }

    return;
}

void
fix_plus_plus_recursive(xmlNode * target)
{
    /* TODO: Remove recursion and use xpath searches for value++ */
    xmlNode *child = NULL;

    for (xmlAttrPtr a = pcmk__xe_first_attr(target); a != NULL; a = a->next) {
        const char *p_name = (const char *) a->name;
        const char *p_value = pcmk__xml_attr_value(a);

        expand_plus_plus(target, p_name, p_value);
    }
    for (child = pcmk__xml_first_child(target); child != NULL;
         child = pcmk__xml_next(child)) {
        fix_plus_plus_recursive(child);
    }
}

void
expand_plus_plus(xmlNode * target, const char *name, const char *value)
{
    int offset = 1;
    int name_len = 0;
    int int_value = 0;
    int value_len = 0;

    const char *old_value = NULL;

    if (value == NULL || name == NULL) {
        return;
    }

    old_value = crm_element_value(target, name);

    if (old_value == NULL) {
        /* if no previous value, set unexpanded */
        goto set_unexpanded;

    } else if (strstr(value, name) != value) {
        goto set_unexpanded;
    }

    name_len = strlen(name);
    value_len = strlen(value);
    if (value_len < (name_len + 2)
        || value[name_len] != '+' || (value[name_len + 1] != '+' && value[name_len + 1] != '=')) {
        goto set_unexpanded;
    }

    /* if we are expanding ourselves,
     * then no previous value was set and leave int_value as 0
     */
    if (old_value != value) {
        int_value = char2score(old_value);
    }

    if (value[name_len + 1] != '+') {
        const char *offset_s = value + (name_len + 2);

        offset = char2score(offset_s);
    }
    int_value += offset;

    if (int_value > INFINITY) {
        int_value = (int)INFINITY;
    }

    crm_xml_add_int(target, name, int_value);
    return;

  set_unexpanded:
    if (old_value == value) {
        /* the old value is already set, nothing to do */
        return;
    }
    crm_xml_add(target, name, value);
    return;
}

void
pcmk__xe_remove_matching_attrs(xmlNode *element,
                               bool (*match)(xmlAttrPtr, void *),
                               void *user_data)
{
    xmlAttrPtr next = NULL;

    for (xmlAttrPtr a = pcmk__xe_first_attr(element); a != NULL; a = next) {
        next = a->next; // Grab now because attribute might get removed
        if ((match == NULL) || match(a, user_data)) {
            if (!pcmk__check_acl(element, NULL, xpf_acl_write)) {
                crm_trace("ACLs prevent removal of attributes (%s and "
                          "possibly others) from %s element",
                          (const char *) a->name, (const char *) element->name);
                return; // ACLs apply to element, not particular attributes
            }

            if (pcmk__tracking_xml_changes(element, false)) {
                // Leave (marked for removal) until after diff is calculated
                set_parent_flag(element, xpf_dirty);
                pcmk__set_xml_flags((xml_private_t *) a->_private, xpf_deleted);
            } else {
                xmlRemoveProp(a);
            }
        }
    }
}

xmlDoc *
getDocPtr(xmlNode * node)
{
    xmlDoc *doc = NULL;

    CRM_CHECK(node != NULL, return NULL);

    doc = node->doc;
    if (doc == NULL) {
        doc = xmlNewDoc((pcmkXmlStr) "1.0");
        xmlDocSetRootElement(doc, node);
        xmlSetTreeDoc(node, doc);
    }
    return doc;
}

xmlNode *
add_node_copy(xmlNode * parent, xmlNode * src_node)
{
    xmlNode *child = NULL;
    xmlDoc *doc = getDocPtr(parent);

    CRM_CHECK(src_node != NULL, return NULL);

    child = xmlDocCopyNode(src_node, doc, 1);
    xmlAddChild(parent, child);
    pcmk__mark_xml_created(child);
    return child;
}

int
add_node_nocopy(xmlNode * parent, const char *name, xmlNode * child)
{
    add_node_copy(parent, child);
    free_xml(child);
    return 1;
}

xmlNode *
create_xml_node(xmlNode * parent, const char *name)
{
    xmlDoc *doc = NULL;
    xmlNode *node = NULL;

    if (pcmk__str_empty(name)) {
        CRM_CHECK(name != NULL && name[0] == 0, return NULL);
        return NULL;
    }

    if (parent == NULL) {
        doc = xmlNewDoc((pcmkXmlStr) "1.0");
        node = xmlNewDocRawNode(doc, NULL, (pcmkXmlStr) name, NULL);
        xmlDocSetRootElement(doc, node);

    } else {
        doc = getDocPtr(parent);
        node = xmlNewDocRawNode(doc, NULL, (pcmkXmlStr) name, NULL);
        xmlAddChild(parent, node);
    }
    pcmk__mark_xml_created(node);
    return node;
}

xmlNode *
pcmk_create_xml_text_node(xmlNode * parent, const char *name, const char *content)
{
    xmlNode *node = create_xml_node(parent, name);

    if (node != NULL) {
        xmlNodeSetContent(node, (pcmkXmlStr) content);
    }

    return node;
}

xmlNode *
pcmk_create_html_node(xmlNode * parent, const char *element_name, const char *id,
                      const char *class_name, const char *text)
{
    xmlNode *node = pcmk_create_xml_text_node(parent, element_name, text);

    if (class_name != NULL) {
        crm_xml_add(node, "class", class_name);
    }

    if (id != NULL) {
        crm_xml_add(node, "id", id);
    }

    return node;
}

void
pcmk_free_xml_subtree(xmlNode *xml)
{
    xmlUnlinkNode(xml); // Detaches from parent and siblings
    xmlFreeNode(xml);   // Frees
}

static void
free_xml_with_position(xmlNode * child, int position)
{
    if (child != NULL) {
        xmlNode *top = NULL;
        xmlDoc *doc = child->doc;
        xml_private_t *p = child->_private;

        if (doc != NULL) {
            top = xmlDocGetRootElement(doc);
        }

        if (doc != NULL && top == child) {
            /* Free everything */
            xmlFreeDoc(doc);

        } else if (pcmk__check_acl(child, NULL, xpf_acl_write) == FALSE) {
            int offset = 0;
            char buffer[PCMK__BUFFER_SIZE];

            pcmk__element_xpath(NULL, child, buffer, offset, sizeof(buffer));
            crm_trace("Cannot remove %s %x", buffer, p->flags);
            return;

        } else {
            if (doc && pcmk__tracking_xml_changes(child, FALSE)
                && !pcmk_is_set(p->flags, xpf_created)) {
                int offset = 0;
                char buffer[PCMK__BUFFER_SIZE];

                if (pcmk__element_xpath(NULL, child, buffer, offset,
                                        sizeof(buffer)) > 0) {
                    pcmk__deleted_xml_t *deleted_obj = NULL;

                    crm_trace("Deleting %s %p from %p", buffer, child, doc);

                    deleted_obj = calloc(1, sizeof(pcmk__deleted_xml_t));
                    deleted_obj->path = strdup(buffer);

                    deleted_obj->position = -1;
                    /* Record the "position" only for XML comments for now */
                    if (child->type == XML_COMMENT_NODE) {
                        if (position >= 0) {
                            deleted_obj->position = position;

                        } else {
                            deleted_obj->position = pcmk__xml_position(child, xpf_skip);
                        }
                    }

                    p = doc->_private;
                    p->deleted_objs = g_list_append(p->deleted_objs, deleted_obj);
                    pcmk__set_xml_doc_flag(child, xpf_dirty);
                }
            }
            pcmk_free_xml_subtree(child);
        }
    }
}


void
free_xml(xmlNode * child)
{
    free_xml_with_position(child, -1);
}

xmlNode *
copy_xml(xmlNode * src)
{
    xmlDoc *doc = xmlNewDoc((pcmkXmlStr) "1.0");
    xmlNode *copy = xmlDocCopyNode(src, doc, 1);

    xmlDocSetRootElement(doc, copy);
    xmlSetTreeDoc(copy, doc);
    return copy;
}

static void
log_xmllib_err(void *ctx, const char *fmt, ...)
G_GNUC_PRINTF(2, 3);

// Log an XML library error
static void
log_xmllib_err(void *ctx, const char *fmt, ...)
{
    va_list ap;
    static struct qb_log_callsite *xml_error_cs = NULL;

    if (xml_error_cs == NULL) {
        xml_error_cs = qb_log_callsite_get(
            __func__, __FILE__, "xml library error", LOG_TRACE, __LINE__, crm_trace_nonlog);
    }

    va_start(ap, fmt);
    if (xml_error_cs && xml_error_cs->targets) {
        PCMK__XML_LOG_BASE(LOG_ERR, TRUE,
                           crm_abort(__FILE__, __PRETTY_FUNCTION__, __LINE__, "xml library error",
                                     TRUE, TRUE),
                           "XML Error: ", fmt, ap);
    } else {
        PCMK__XML_LOG_BASE(LOG_ERR, TRUE, 0, "XML Error: ", fmt, ap);
    }
    va_end(ap);
}

xmlNode *
string2xml(const char *input)
{
    xmlNode *xml = NULL;
    xmlDocPtr output = NULL;
    xmlParserCtxtPtr ctxt = NULL;
    xmlErrorPtr last_error = NULL;

    if (input == NULL) {
        crm_err("Can't parse NULL input");
        return NULL;
    }

    /* create a parser context */
    ctxt = xmlNewParserCtxt();
    CRM_CHECK(ctxt != NULL, return NULL);

    xmlCtxtResetLastError(ctxt);
    xmlSetGenericErrorFunc(ctxt, log_xmllib_err);
    output = xmlCtxtReadDoc(ctxt, (pcmkXmlStr) input, NULL, NULL,
                            PCMK__XML_PARSE_OPTS);
    if (output) {
        xml = xmlDocGetRootElement(output);
    }
    last_error = xmlCtxtGetLastError(ctxt);
    if (last_error && last_error->code != XML_ERR_OK) {
        /* crm_abort(__FILE__,__func__,__LINE__, "last_error->code != XML_ERR_OK", TRUE, TRUE); */
        /*
         * http://xmlsoft.org/html/libxml-xmlerror.html#xmlErrorLevel
         * http://xmlsoft.org/html/libxml-xmlerror.html#xmlParserErrors
         */
        crm_warn("Parsing failed (domain=%d, level=%d, code=%d): %s",
                 last_error->domain, last_error->level, last_error->code, last_error->message);

        if (last_error->code == XML_ERR_DOCUMENT_EMPTY) {
            CRM_LOG_ASSERT("Cannot parse an empty string");

        } else if (last_error->code != XML_ERR_DOCUMENT_END) {
            crm_err("Couldn't%s parse %d chars: %s", xml ? " fully" : "", (int)strlen(input),
                    input);
            if (xml != NULL) {
                crm_log_xml_err(xml, "Partial");
            }

        } else {
            int len = strlen(input);
            int lpc = 0;

            while(lpc < len) {
                crm_warn("Parse error[+%.3d]: %.80s", lpc, input+lpc);
                lpc += 80;
            }

            CRM_LOG_ASSERT("String parsing error");
        }
    }

    xmlFreeParserCtxt(ctxt);
    return xml;
}

xmlNode *
stdin2xml(void)
{
    size_t data_length = 0;
    size_t read_chars = 0;

    char *xml_buffer = NULL;
    xmlNode *xml_obj = NULL;

    do {
        xml_buffer = pcmk__realloc(xml_buffer, data_length + PCMK__BUFFER_SIZE);
        read_chars = fread(xml_buffer + data_length, 1, PCMK__BUFFER_SIZE,
                           stdin);
        data_length += read_chars;
    } while (read_chars == PCMK__BUFFER_SIZE);

    if (data_length == 0) {
        crm_warn("No XML supplied on stdin");
        free(xml_buffer);
        return NULL;
    }

    xml_buffer[data_length] = '\0';
    xml_obj = string2xml(xml_buffer);
    free(xml_buffer);

    crm_log_xml_trace(xml_obj, "Created fragment");
    return xml_obj;
}

static char *
decompress_file(const char *filename)
{
    char *buffer = NULL;
    int rc = 0;
    size_t length = 0, read_len = 0;
    BZFILE *bz_file = NULL;
    FILE *input = fopen(filename, "r");

    if (input == NULL) {
        crm_perror(LOG_ERR, "Could not open %s for reading", filename);
        return NULL;
    }

    bz_file = BZ2_bzReadOpen(&rc, input, 0, 0, NULL, 0);
    if (rc != BZ_OK) {
        crm_err("Could not prepare to read compressed %s: %s "
                CRM_XS " bzerror=%d", filename, bz2_strerror(rc), rc);
        BZ2_bzReadClose(&rc, bz_file);
        return NULL;
    }

    rc = BZ_OK;
    // cppcheck seems not to understand the abort-logic in pcmk__realloc
    // cppcheck-suppress memleak
    while (rc == BZ_OK) {
        buffer = pcmk__realloc(buffer, PCMK__BUFFER_SIZE + length + 1);
        read_len = BZ2_bzRead(&rc, bz_file, buffer + length, PCMK__BUFFER_SIZE);

        crm_trace("Read %ld bytes from file: %d", (long)read_len, rc);

        if (rc == BZ_OK || rc == BZ_STREAM_END) {
            length += read_len;
        }
    }

    buffer[length] = '\0';

    if (rc != BZ_STREAM_END) {
        crm_err("Could not read compressed %s: %s "
                CRM_XS " bzerror=%d", filename, bz2_strerror(rc), rc);
        free(buffer);
        buffer = NULL;
    }

    BZ2_bzReadClose(&rc, bz_file);
    fclose(input);
    return buffer;
}

void
pcmk__strip_xml_text(xmlNode *xml)
{
    xmlNode *iter = xml->children;

    while (iter) {
        xmlNode *next = iter->next;

        switch (iter->type) {
            case XML_TEXT_NODE:
                /* Remove it */
                pcmk_free_xml_subtree(iter);
                break;

            case XML_ELEMENT_NODE:
                /* Search it */
                pcmk__strip_xml_text(iter);
                break;

            default:
                /* Leave it */
                break;
        }

        iter = next;
    }
}

xmlNode *
filename2xml(const char *filename)
{
    xmlNode *xml = NULL;
    xmlDocPtr output = NULL;
    gboolean uncompressed = TRUE;
    xmlParserCtxtPtr ctxt = NULL;
    xmlErrorPtr last_error = NULL;

    /* create a parser context */
    ctxt = xmlNewParserCtxt();
    CRM_CHECK(ctxt != NULL, return NULL);

    xmlCtxtResetLastError(ctxt);
    xmlSetGenericErrorFunc(ctxt, log_xmllib_err);

    if (filename) {
        uncompressed = !pcmk__ends_with_ext(filename, ".bz2");
    }

    if (filename == NULL || !strcmp(filename, "-")) {
        /* STDIN_FILENO == fileno(stdin) */
        output = xmlCtxtReadFd(ctxt, STDIN_FILENO, "unknown.xml", NULL,
                               PCMK__XML_PARSE_OPTS);

    } else if (uncompressed) {
        output = xmlCtxtReadFile(ctxt, filename, NULL, PCMK__XML_PARSE_OPTS);

    } else {
        char *input = decompress_file(filename);

        output = xmlCtxtReadDoc(ctxt, (pcmkXmlStr) input, NULL, NULL,
                                PCMK__XML_PARSE_OPTS);
        free(input);
    }

    if (output && (xml = xmlDocGetRootElement(output))) {
        pcmk__strip_xml_text(xml);
    }

    last_error = xmlCtxtGetLastError(ctxt);
    if (last_error && last_error->code != XML_ERR_OK) {
        /* crm_abort(__FILE__,__func__,__LINE__, "last_error->code != XML_ERR_OK", TRUE, TRUE); */
        /*
         * http://xmlsoft.org/html/libxml-xmlerror.html#xmlErrorLevel
         * http://xmlsoft.org/html/libxml-xmlerror.html#xmlParserErrors
         */
        crm_err("Parsing failed (domain=%d, level=%d, code=%d): %s",
                last_error->domain, last_error->level, last_error->code, last_error->message);

        if (last_error && last_error->code != XML_ERR_OK) {
            crm_err("Couldn't%s parse %s", xml ? " fully" : "", filename);
            if (xml != NULL) {
                crm_log_xml_err(xml, "Partial");
            }
        }
    }

    xmlFreeParserCtxt(ctxt);
    return xml;
}

const char *
pcmk__xe_add_last_written(xmlNode *xe)
{
    const char *now_str = pcmk__epoch2str(NULL);

    return crm_xml_add(xe, XML_CIB_ATTR_WRITTEN,
                       now_str ? now_str : "Could not determine current time");
}

void
crm_xml_sanitize_id(char *id)
{
    char *c;

    for (c = id; *c; ++c) {
        /* @TODO Sanitize more comprehensively */
        switch (*c) {
            case ':':
            case '#':
                *c = '.';
        }
    }
}

void
crm_xml_set_id(xmlNode *xml, const char *format, ...)
{
    va_list ap;
    int len = 0;
    char *id = NULL;

    /* equivalent to crm_strdup_printf() */
    va_start(ap, format);
    len = vasprintf(&id, format, ap);
    va_end(ap);
    CRM_ASSERT(len > 0);

    crm_xml_sanitize_id(id);
    crm_xml_add(xml, XML_ATTR_ID, id);
    free(id);
}

static int
write_xml_stream(xmlNode *xml_node, const char *filename, FILE *stream,
                 bool compress, unsigned int *nbytes)
{
    int rc = pcmk_rc_ok;
    char *buffer = NULL;

    *nbytes = 0;
    crm_log_xml_trace(xml_node, "writing");

    buffer = dump_xml_formatted(xml_node);
    CRM_CHECK(buffer && strlen(buffer),
              crm_log_xml_warn(xml_node, "formatting failed");
              rc = pcmk_rc_error;
              goto bail);

    if (compress) {
        unsigned int in = 0;
        BZFILE *bz_file = NULL;

        rc = BZ_OK;
        bz_file = BZ2_bzWriteOpen(&rc, stream, 5, 0, 30);
        if (rc != BZ_OK) {
            crm_warn("Not compressing %s: could not prepare file stream: %s "
                     CRM_XS " bzerror=%d", filename, bz2_strerror(rc), rc);
        } else {
            BZ2_bzWrite(&rc, bz_file, buffer, strlen(buffer));
            if (rc != BZ_OK) {
                crm_warn("Not compressing %s: could not compress data: %s "
                         CRM_XS " bzerror=%d errno=%d",
                         filename, bz2_strerror(rc), rc, errno);
            }
        }

        if (rc == BZ_OK) {
            BZ2_bzWriteClose(&rc, bz_file, 0, &in, nbytes);
            if (rc != BZ_OK) {
                crm_warn("Not compressing %s: could not write compressed data: %s "
                         CRM_XS " bzerror=%d errno=%d",
                         filename, bz2_strerror(rc), rc, errno);
                *nbytes = 0; // retry without compression
            } else {
                crm_trace("Compressed XML for %s from %u bytes to %u",
                          filename, in, *nbytes);
            }
        }
        rc = pcmk_rc_ok; // Either true, or we'll retry without compression
    }

    if (*nbytes == 0) {
        rc = fprintf(stream, "%s", buffer);
        if (rc < 0) {
            rc = errno;
            crm_perror(LOG_ERR, "writing %s", filename);
        } else {
            *nbytes = (unsigned int) rc;
            rc = pcmk_rc_ok;
        }
    }

  bail:

    if (fflush(stream) != 0) {
        rc = errno;
        crm_perror(LOG_ERR, "flushing %s", filename);
    }

    /* Don't report error if the file does not support synchronization */
    if (fsync(fileno(stream)) < 0 && errno != EROFS  && errno != EINVAL) {
        rc = errno;
        crm_perror(LOG_ERR, "synchronizing %s", filename);
    }

    fclose(stream);

    crm_trace("Saved %d bytes to %s as XML", *nbytes, filename);
    free(buffer);

    return rc;
}

int
write_xml_fd(xmlNode * xml_node, const char *filename, int fd, gboolean compress)
{
    FILE *stream = NULL;
    unsigned int nbytes = 0;
    int rc = pcmk_rc_ok;

    CRM_CHECK(xml_node && (fd > 0), return -EINVAL);
    stream = fdopen(fd, "w");
    if (stream == NULL) {
        return -errno;
    }
    rc = write_xml_stream(xml_node, filename, stream, compress, &nbytes);
    if (rc != pcmk_rc_ok) {
        return pcmk_rc2legacy(rc);
    }
    return (int) nbytes;
}

int
write_xml_file(xmlNode * xml_node, const char *filename, gboolean compress)
{
    FILE *stream = NULL;
    unsigned int nbytes = 0;
    int rc = pcmk_rc_ok;

    CRM_CHECK(xml_node && filename, return -EINVAL);
    stream = fopen(filename, "w");
    if (stream == NULL) {
        return -errno;
    }
    rc = write_xml_stream(xml_node, filename, stream, compress, &nbytes);
    if (rc != pcmk_rc_ok) {
        return pcmk_rc2legacy(rc);
    }
    return (int) nbytes;
}

// Replace a portion of a dynamically allocated string (reallocating memory)
static char *
replace_text(char *text, int start, int *length, const char *replace)
{
    int lpc;
    int offset = strlen(replace) - 1;   /* We have space for 1 char already */

    *length += offset;
    text = pcmk__realloc(text, *length);

    for (lpc = (*length) - 1; lpc > (start + offset); lpc--) {
        text[lpc] = text[lpc - offset];
    }

    memcpy(text + start, replace, offset + 1);
    return text;
}

char *
crm_xml_escape(const char *text)
{
    int index;
    int changes = 0;
    int length = 1 + strlen(text);
    char *copy = strdup(text);

    /*
     * When xmlCtxtReadDoc() parses &lt; and friends in a
     * value, it converts them to their human readable
     * form.
     *
     * If one uses xmlNodeDump() to convert it back to a
     * string, all is well, because special characters are
     * converted back to their escape sequences.
     *
     * However xmlNodeDump() is randomly dog slow, even with the same
     * input. So we need to replicate the escaping in our custom
     * version so that the result can be re-parsed by xmlCtxtReadDoc()
     * when necessary.
     */

    for (index = 0; index < length; index++) {
        switch (copy[index]) {
            case 0:
                break;
            case '<':
                copy = replace_text(copy, index, &length, "&lt;");
                changes++;
                break;
            case '>':
                copy = replace_text(copy, index, &length, "&gt;");
                changes++;
                break;
            case '"':
                copy = replace_text(copy, index, &length, "&quot;");
                changes++;
                break;
            case '\'':
                copy = replace_text(copy, index, &length, "&apos;");
                changes++;
                break;
            case '&':
                copy = replace_text(copy, index, &length, "&amp;");
                changes++;
                break;
            case '\t':
                /* Might as well just expand to a few spaces... */
                copy = replace_text(copy, index, &length, "    ");
                changes++;
                break;
            case '\n':
                /* crm_trace("Convert: \\%.3o", copy[index]); */
                copy = replace_text(copy, index, &length, "\\n");
                changes++;
                break;
            case '\r':
                copy = replace_text(copy, index, &length, "\\r");
                changes++;
                break;
                /* For debugging...
            case '\\':
                crm_trace("Passthrough: \\%c", copy[index+1]);
                break;
                */
            default:
                /* Check for and replace non-printing characters with their octal equivalent */
                if(copy[index] < ' ' || copy[index] > '~') {
                    char *replace = crm_strdup_printf("\\%.3o", copy[index]);

                    /* crm_trace("Convert to octal: \\%.3o", copy[index]); */
                    copy = replace_text(copy, index, &length, replace);
                    free(replace);
                    changes++;
                }
        }
    }

    if (changes) {
        crm_trace("Dumped '%s'", copy);
    }
    return copy;
}

static inline void
dump_xml_attr(xmlAttrPtr attr, int options, char **buffer, int *offset, int *max)
{
    char *p_value = NULL;
    const char *p_name = NULL;
    xml_private_t *p = NULL;

    CRM_ASSERT(buffer != NULL);
    if (attr == NULL || attr->children == NULL) {
        return;
    }

    p = attr->_private;
    if (p && pcmk_is_set(p->flags, xpf_deleted)) {
        return;
    }

    p_name = (const char *)attr->name;
    p_value = crm_xml_escape((const char *)attr->children->content);
    buffer_print(*buffer, *max, *offset, " %s=\"%s\"", p_name, p_value);
    free(p_value);
}

// Log an XML element (and any children) in a formatted way
void
pcmk__xe_log(int log_level, const char *file, const char *function, int line,
             const char *prefix, xmlNode *data, int depth, int options)
{
    int max = 0;
    int offset = 0;
    const char *name = NULL;
    const char *hidden = NULL;

    xmlNode *child = NULL;

    if ((data == NULL) || (log_level == LOG_NEVER)) {
        return;
    }

    name = crm_element_name(data);

    if (pcmk_is_set(options, xml_log_option_open)) {
        char *buffer = NULL;

        insert_prefix(options, &buffer, &offset, &max, depth);

        if (data->type == XML_COMMENT_NODE) {
            buffer_print(buffer, max, offset, "<!--%s-->", data->content);

        } else {
            buffer_print(buffer, max, offset, "<%s", name);

            hidden = crm_element_value(data, "hidden");
            for (xmlAttrPtr a = pcmk__xe_first_attr(data); a != NULL;
                 a = a->next) {

                xml_private_t *p = a->_private;
                const char *p_name = (const char *) a->name;
                const char *p_value = pcmk__xml_attr_value(a);
                char *p_copy = NULL;

                if (pcmk_is_set(p->flags, xpf_deleted)) {
                    continue;
                } else if (pcmk_any_flags_set(options,
                                              xml_log_option_diff_plus
                                              |xml_log_option_diff_minus)
                           && (strcmp(XML_DIFF_MARKER, p_name) == 0)) {
                    continue;

                } else if (hidden != NULL && p_name[0] != 0 && strstr(hidden, p_name) != NULL) {
                    p_copy = strdup("*****");

                } else {
                    p_copy = crm_xml_escape(p_value);
                }

                buffer_print(buffer, max, offset, " %s=\"%s\"", p_name, p_copy);
                free(p_copy);
            }

            if(xml_has_children(data) == FALSE) {
                buffer_print(buffer, max, offset, "/>");

            } else if (pcmk_is_set(options, xml_log_option_children)) {
                buffer_print(buffer, max, offset, ">");

            } else {
                buffer_print(buffer, max, offset, "/>");
            }
        }

        do_crm_log_alias(log_level, file, function, line, "%s %s", prefix, buffer);
        free(buffer);
    }

    if(data->type == XML_COMMENT_NODE) {
        return;

    } else if(xml_has_children(data) == FALSE) {
        return;

    } else if (pcmk_is_set(options, xml_log_option_children)) {
        offset = 0;
        max = 0;

        for (child = pcmk__xml_first_child(data); child != NULL;
             child = pcmk__xml_next(child)) {
            pcmk__xe_log(log_level, file, function, line, prefix, child,
                         depth + 1,
                         options|xml_log_option_open|xml_log_option_close);
        }
    }

    if (pcmk_is_set(options, xml_log_option_close)) {
        char *buffer = NULL;

        insert_prefix(options, &buffer, &offset, &max, depth);
        buffer_print(buffer, max, offset, "</%s>", name);

        do_crm_log_alias(log_level, file, function, line, "%s %s", prefix, buffer);
        free(buffer);
    }
}

// Log XML portions that have been marked as changed
static void
log_xml_changes(int log_level, const char *file, const char *function, int line,
                const char *prefix, xmlNode *data, int depth, int options)
{
    xml_private_t *p;
    char *prefix_m = NULL;
    xmlNode *child = NULL;

    if ((data == NULL) || (log_level == LOG_NEVER)) {
        return;
    }

    p = data->_private;

    prefix_m = strdup(prefix);
    prefix_m[1] = '+';

    if (pcmk_all_flags_set(p->flags, xpf_dirty|xpf_created)) {
        /* Continue and log full subtree */
        pcmk__xe_log(log_level, file, function, line, prefix_m, data, depth,
                     options|xml_log_option_open|xml_log_option_close
                        |xml_log_option_children);

    } else if (pcmk_is_set(p->flags, xpf_dirty)) {
        char *spaces = calloc(80, 1);
        int s_count = 0, s_max = 80;
        char *prefix_del = NULL;
        char *prefix_moved = NULL;
        const char *flags = prefix;

        insert_prefix(options, &spaces, &s_count, &s_max, depth);
        prefix_del = strdup(prefix);
        prefix_del[0] = '-';
        prefix_del[1] = '-';
        prefix_moved = strdup(prefix);
        prefix_moved[1] = '~';

        if (pcmk_is_set(p->flags, xpf_moved)) {
            flags = prefix_moved;
        } else {
            flags = prefix;
        }

        pcmk__xe_log(log_level, file, function, line, flags, data, depth,
                     options|xml_log_option_open);

        for (xmlAttrPtr a = pcmk__xe_first_attr(data); a != NULL; a = a->next) {
            const char *aname = (const char*) a->name;

            p = a->_private;
            if (pcmk_is_set(p->flags, xpf_deleted)) {
                const char *value = crm_element_value(data, aname);
                flags = prefix_del;
                do_crm_log_alias(log_level, file, function, line,
                                 "%s %s @%s=%s", flags, spaces, aname, value);

            } else if (pcmk_is_set(p->flags, xpf_dirty)) {
                const char *value = crm_element_value(data, aname);

                if (pcmk_is_set(p->flags, xpf_created)) {
                    flags = prefix_m;

                } else if (pcmk_is_set(p->flags, xpf_modified)) {
                    flags = prefix;

                } else if (pcmk_is_set(p->flags, xpf_moved)) {
                    flags = prefix_moved;

                } else {
                    flags = prefix;
                }
                do_crm_log_alias(log_level, file, function, line,
                                 "%s %s @%s=%s", flags, spaces, aname, value);
            }
        }
        free(prefix_moved);
        free(prefix_del);
        free(spaces);

        for (child = pcmk__xml_first_child(data); child != NULL;
             child = pcmk__xml_next(child)) {
            log_xml_changes(log_level, file, function, line, prefix, child,
                            depth + 1, options);
        }

        pcmk__xe_log(log_level, file, function, line, prefix, data, depth,
                     options|xml_log_option_close);

    } else {
        for (child = pcmk__xml_first_child(data); child != NULL;
             child = pcmk__xml_next(child)) {
            log_xml_changes(log_level, file, function, line, prefix, child,
                            depth + 1, options);
        }
    }

    free(prefix_m);

}

void
log_data_element(int log_level, const char *file, const char *function, int line,
                 const char *prefix, xmlNode * data, int depth, int options)
{
    xmlNode *a_child = NULL;

    char *prefix_m = NULL;

    if (log_level == LOG_NEVER) {
        return;
    }

    if (prefix == NULL) {
        prefix = "";
    }

    /* Since we use the same file and line, to avoid confusing libqb, we need to use the same format strings */
    if (data == NULL) {
        do_crm_log_alias(log_level, file, function, line, "%s: %s", prefix,
                         "No data to dump as XML");
        return;
    }

    if (pcmk_is_set(options, xml_log_option_dirty_add)) {
        log_xml_changes(log_level, file, function, line, prefix, data, depth,
                        options);
        return;
    }

    if (pcmk_is_set(options, xml_log_option_formatted)) {
        if (pcmk_is_set(options, xml_log_option_diff_plus)
            && (data->children == NULL || crm_element_value(data, XML_DIFF_MARKER))) {
            options |= xml_log_option_diff_all;
            prefix_m = strdup(prefix);
            prefix_m[1] = '+';
            prefix = prefix_m;

        } else if (pcmk_is_set(options, xml_log_option_diff_minus)
                   && (data->children == NULL || crm_element_value(data, XML_DIFF_MARKER))) {
            options |= xml_log_option_diff_all;
            prefix_m = strdup(prefix);
            prefix_m[1] = '-';
            prefix = prefix_m;
        }
    }

    if (pcmk_is_set(options, xml_log_option_diff_short)
               && !pcmk_is_set(options, xml_log_option_diff_all)) {
        /* Still searching for the actual change */
        for (a_child = pcmk__xml_first_child(data); a_child != NULL;
             a_child = pcmk__xml_next(a_child)) {
            log_data_element(log_level, file, function, line, prefix, a_child, depth + 1, options);
        }
    } else {
        pcmk__xe_log(log_level, file, function, line, prefix, data, depth,
                     options|xml_log_option_open|xml_log_option_close
                        |xml_log_option_children);
    }
    free(prefix_m);
}

static void
dump_filtered_xml(xmlNode * data, int options, char **buffer, int *offset, int *max)
{
    for (xmlAttrPtr a = pcmk__xe_first_attr(data); a != NULL; a = a->next) {
        if (!pcmk__xa_filterable((const char *) (a->name))) {
            dump_xml_attr(a, options, buffer, offset, max);
        }
    }
}

static void
dump_xml_element(xmlNode * data, int options, char **buffer, int *offset, int *max, int depth)
{
    const char *name = NULL;

    CRM_ASSERT(max != NULL);
    CRM_ASSERT(offset != NULL);
    CRM_ASSERT(buffer != NULL);

    if (data == NULL) {
        crm_trace("Nothing to dump");
        return;
    }

    if (*buffer == NULL) {
        *offset = 0;
        *max = 0;
    }

    name = crm_element_name(data);
    CRM_ASSERT(name != NULL);

    insert_prefix(options, buffer, offset, max, depth);
    buffer_print(*buffer, *max, *offset, "<%s", name);

    if (options & xml_log_option_filtered) {
        dump_filtered_xml(data, options, buffer, offset, max);

    } else {
        for (xmlAttrPtr a = pcmk__xe_first_attr(data); a != NULL; a = a->next) {
            dump_xml_attr(a, options, buffer, offset, max);
        }
    }

    if (data->children == NULL) {
        buffer_print(*buffer, *max, *offset, "/>");

    } else {
        buffer_print(*buffer, *max, *offset, ">");
    }

    if (options & xml_log_option_formatted) {
        buffer_print(*buffer, *max, *offset, "\n");
    }

    if (data->children) {
        xmlNode *xChild = NULL;
        for(xChild = data->children; xChild != NULL; xChild = xChild->next) {
            pcmk__xml2text(xChild, options, buffer, offset, max, depth + 1);
        }

        insert_prefix(options, buffer, offset, max, depth);
        buffer_print(*buffer, *max, *offset, "</%s>", name);

        if (options & xml_log_option_formatted) {
            buffer_print(*buffer, *max, *offset, "\n");
        }
    }
}

static void
dump_xml_text(xmlNode * data, int options, char **buffer, int *offset, int *max, int depth)
{
    CRM_ASSERT(max != NULL);
    CRM_ASSERT(offset != NULL);
    CRM_ASSERT(buffer != NULL);

    if (data == NULL) {
        crm_trace("Nothing to dump");
        return;
    }

    if (*buffer == NULL) {
        *offset = 0;
        *max = 0;
    }

    insert_prefix(options, buffer, offset, max, depth);

    buffer_print(*buffer, *max, *offset, "%s", data->content);

    if (options & xml_log_option_formatted) {
        buffer_print(*buffer, *max, *offset, "\n");
    }
}

static void
dump_xml_cdata(xmlNode * data, int options, char **buffer, int *offset, int *max, int depth)
{
    CRM_ASSERT(max != NULL);
    CRM_ASSERT(offset != NULL);
    CRM_ASSERT(buffer != NULL);

    if (data == NULL) {
        crm_trace("Nothing to dump");
        return;
    }

    if (*buffer == NULL) {
        *offset = 0;
        *max = 0;
    }

    insert_prefix(options, buffer, offset, max, depth);

    buffer_print(*buffer, *max, *offset, "<![CDATA[");
    buffer_print(*buffer, *max, *offset, "%s", data->content);
    buffer_print(*buffer, *max, *offset, "]]>");

    if (options & xml_log_option_formatted) {
        buffer_print(*buffer, *max, *offset, "\n");
    }
}

static void
dump_xml_comment(xmlNode * data, int options, char **buffer, int *offset, int *max, int depth)
{
    CRM_ASSERT(max != NULL);
    CRM_ASSERT(offset != NULL);
    CRM_ASSERT(buffer != NULL);

    if (data == NULL) {
        crm_trace("Nothing to dump");
        return;
    }

    if (*buffer == NULL) {
        *offset = 0;
        *max = 0;
    }

    insert_prefix(options, buffer, offset, max, depth);

    buffer_print(*buffer, *max, *offset, "<!--");
    buffer_print(*buffer, *max, *offset, "%s", data->content);
    buffer_print(*buffer, *max, *offset, "-->");

    if (options & xml_log_option_formatted) {
        buffer_print(*buffer, *max, *offset, "\n");
    }
}

#define PCMK__XMLDUMP_STATS 0

void
pcmk__xml2text(xmlNode *data, int options, char **buffer, int *offset,
               int *max, int depth)
{
    if(data == NULL) {
        *offset = 0;
        *max = 0;
        return;
    }

    if (!pcmk_is_set(options, xml_log_option_filtered)
        && pcmk_is_set(options, xml_log_option_full_fledged)) {
        /* libxml's serialization reuse is a good idea, sadly we cannot
           apply it for the filtered cases (preceding filtering pass
           would preclude further reuse of such in-situ modified XML
           in generic context and is likely not a win performance-wise),
           and there's also a historically unstable throughput argument
           (likely stemming from memory allocation overhead, eventhough
           that shall be minimized with defaults preset in crm_xml_init) */
#if (PCMK__XMLDUMP_STATS - 0)
        time_t next, new = time(NULL);
#endif
        xmlDoc *doc;
        xmlOutputBuffer *xml_buffer;

        doc = getDocPtr(data);
        /* doc will only be NULL if data is */
        CRM_CHECK(doc != NULL, return);

        xml_buffer = xmlAllocOutputBuffer(NULL);
        CRM_ASSERT(xml_buffer != NULL);

        /* XXX we could setup custom allocation scheme for the particular
               buffer, but it's subsumed with crm_xml_init that needs to
               be invoked prior to entering this function as such, since
               its other branch vitally depends on it -- what can be done
               about this all is to have a facade parsing functions that
               would 100% mark entering libxml code for us, since we don't
               do anything as crazy as swapping out the binary form of the
               parsed tree (but those would need to be strictly used as
               opposed to libxml's raw functions) */

        xmlNodeDumpOutput(xml_buffer, doc, data, 0,
                          (options & xml_log_option_formatted), NULL);
        /* attempt adding final NL - failing shouldn't be fatal here */
        (void) xmlOutputBufferWrite(xml_buffer, sizeof("\n") - 1, "\n");
        if (xml_buffer->buffer != NULL) {
            buffer_print(*buffer, *max, *offset, "%s",
                         (char *) xmlBufContent(xml_buffer->buffer));
        }

#if (PCMK__XMLDUMP_STATS - 0)
        next = time(NULL);
        if ((now + 1) < next) {
            crm_log_xml_trace(data, "Long time");
            crm_err("xmlNodeDump() -> %dbytes took %ds", *max, next - now);
        }
#endif

        /* asserted allocation before so there should be something to remove */
        (void) xmlOutputBufferClose(xml_buffer);
        return;
    }

    switch(data->type) {
        case XML_ELEMENT_NODE:
            /* Handle below */
            dump_xml_element(data, options, buffer, offset, max, depth);
            break;
        case XML_TEXT_NODE:
            /* if option xml_log_option_text is enabled, then dump XML_TEXT_NODE */
            if (options & xml_log_option_text) {
                dump_xml_text(data, options, buffer, offset, max, depth);
            }
            return;
        case XML_COMMENT_NODE:
            dump_xml_comment(data, options, buffer, offset, max, depth);
            break;
        case XML_CDATA_SECTION_NODE:
            dump_xml_cdata(data, options, buffer, offset, max, depth);
            break;
        default:
            crm_warn("Unhandled type: %d", data->type);
            return;

            /*
            XML_ATTRIBUTE_NODE = 2
            XML_ENTITY_REF_NODE = 5
            XML_ENTITY_NODE = 6
            XML_PI_NODE = 7
            XML_DOCUMENT_NODE = 9
            XML_DOCUMENT_TYPE_NODE = 10
            XML_DOCUMENT_FRAG_NODE = 11
            XML_NOTATION_NODE = 12
            XML_HTML_DOCUMENT_NODE = 13
            XML_DTD_NODE = 14
            XML_ELEMENT_DECL = 15
            XML_ATTRIBUTE_DECL = 16
            XML_ENTITY_DECL = 17
            XML_NAMESPACE_DECL = 18
            XML_XINCLUDE_START = 19
            XML_XINCLUDE_END = 20
            XML_DOCB_DOCUMENT_NODE = 21
            */
    }

}

void
pcmk__buffer_add_char(char **buffer, int *offset, int *max, char c)
{
    buffer_print(*buffer, *max, *offset, "%c", c);
}

char *
dump_xml_formatted_with_text(xmlNode * an_xml_node)
{
    char *buffer = NULL;
    int offset = 0, max = 0;

    pcmk__xml2text(an_xml_node,
                   xml_log_option_formatted|xml_log_option_full_fledged,
                   &buffer, &offset, &max, 0);
    return buffer;
}

char *
dump_xml_formatted(xmlNode * an_xml_node)
{
    char *buffer = NULL;
    int offset = 0, max = 0;

    pcmk__xml2text(an_xml_node, xml_log_option_formatted, &buffer, &offset,
                   &max, 0);
    return buffer;
}

char *
dump_xml_unformatted(xmlNode * an_xml_node)
{
    char *buffer = NULL;
    int offset = 0, max = 0;

    pcmk__xml2text(an_xml_node, 0, &buffer, &offset, &max, 0);
    return buffer;
}

gboolean
xml_has_children(const xmlNode * xml_root)
{
    if (xml_root != NULL && xml_root->children != NULL) {
        return TRUE;
    }
    return FALSE;
}

void
xml_remove_prop(xmlNode * obj, const char *name)
{
    if (pcmk__check_acl(obj, NULL, xpf_acl_write) == FALSE) {
        crm_trace("Cannot remove %s from %s", name, obj->name);

    } else if (pcmk__tracking_xml_changes(obj, FALSE)) {
        /* Leave in place (marked for removal) until after the diff is calculated */
        xml_private_t *p = NULL;
        xmlAttr *attr = xmlHasProp(obj, (pcmkXmlStr) name);

        p = attr->_private;
        set_parent_flag(obj, xpf_dirty);
        pcmk__set_xml_flags(p, xpf_deleted);
    } else {
        xmlUnsetProp(obj, (pcmkXmlStr) name);
    }
}

void
save_xml_to_file(xmlNode * xml, const char *desc, const char *filename)
{
    char *f = NULL;

    if (filename == NULL) {
        char *uuid = crm_generate_uuid();

        f = crm_strdup_printf("%s/%s", pcmk__get_tmpdir(), uuid);
        filename = f;
        free(uuid);
    }

    crm_info("Saving %s to %s", desc, filename);
    write_xml_file(xml, filename, FALSE);
    free(f);
}

static void
set_attrs_flag(xmlNode *xml, enum xml_private_flags flag)
{
    for (xmlAttr *attr = pcmk__xe_first_attr(xml); attr; attr = attr->next) {
        pcmk__set_xml_flags((xml_private_t *) (attr->_private), flag);
    }
}

static void
mark_attr_deleted(xmlNode *new_xml, const char *element, const char *attr_name,
                  const char *old_value)
{
    xml_private_t *p = new_xml->doc->_private;
    xmlAttr *attr = NULL;

    // Prevent the dirty flag being set recursively upwards
    pcmk__clear_xml_flags(p, xpf_tracking);

    // Restore the old value (and the tracking flag)
    attr = xmlSetProp(new_xml, (pcmkXmlStr) attr_name, (pcmkXmlStr) old_value);
    pcmk__set_xml_flags(p, xpf_tracking);

    // Reset flags (so the attribute doesn't appear as newly created)
    p = attr->_private;
    p->flags = 0;

    // Check ACLs and mark restored value for later removal
    xml_remove_prop(new_xml, attr_name);

    crm_trace("XML attribute %s=%s was removed from %s",
              attr_name, old_value, element);
}

/*
 * \internal
 * \brief Check ACLs for a changed XML attribute
 */
static void
mark_attr_changed(xmlNode *new_xml, const char *element, const char *attr_name,
                  const char *old_value)
{
    char *vcopy = crm_element_value_copy(new_xml, attr_name);

    crm_trace("XML attribute %s was changed from '%s' to '%s' in %s",
              attr_name, old_value, vcopy, element);

    // Restore the original value
    xmlSetProp(new_xml, (pcmkXmlStr) attr_name, (pcmkXmlStr) old_value);

    // Change it back to the new value, to check ACLs
    crm_xml_add(new_xml, attr_name, vcopy);
    free(vcopy);
}

static void
mark_attr_moved(xmlNode *new_xml, const char *element, xmlAttr *old_attr,
                xmlAttr *new_attr, int p_old, int p_new)
{
    xml_private_t *p = new_attr->_private;

    crm_trace("XML attribute %s moved from position %d to %d in %s",
              old_attr->name, p_old, p_new, element);

    // Mark document, element, and all element's parents as changed
    mark_xml_node_dirty(new_xml);

    // Mark attribute as changed
    pcmk__set_xml_flags(p, xpf_dirty|xpf_moved);

    p = (p_old > p_new)? old_attr->_private : new_attr->_private;
    pcmk__set_xml_flags(p, xpf_skip);
}

static void
xml_diff_old_attrs(xmlNode *old_xml, xmlNode *new_xml)
{
    xmlAttr *attr_iter = pcmk__xe_first_attr(old_xml);

    while (attr_iter != NULL) {
        xmlAttr *old_attr = attr_iter;
        xmlAttr *new_attr = xmlHasProp(new_xml, attr_iter->name);
        const char *name = (const char *) attr_iter->name;
        const char *old_value = crm_element_value(old_xml, name);

        attr_iter = attr_iter->next;
        if (new_attr == NULL) {
            mark_attr_deleted(new_xml, (const char *) old_xml->name, name,
                              old_value);

        } else {
            xml_private_t *p = new_attr->_private;
            int new_pos = pcmk__xml_position((xmlNode*) new_attr, xpf_skip);
            int old_pos = pcmk__xml_position((xmlNode*) old_attr, xpf_skip);
            const char *new_value = crm_element_value(new_xml, name);

            // This attribute isn't new
            pcmk__clear_xml_flags(p, xpf_created);

            if (strcmp(new_value, old_value) != 0) {
                mark_attr_changed(new_xml, (const char *) old_xml->name, name,
                                  old_value);

            } else if ((old_pos != new_pos)
                       && !pcmk__tracking_xml_changes(new_xml, TRUE)) {
                mark_attr_moved(new_xml, (const char *) old_xml->name,
                                old_attr, new_attr, old_pos, new_pos);
            }
        }
    }
}

static void
mark_created_attrs(xmlNode *new_xml)
{
    xmlAttr *attr_iter = pcmk__xe_first_attr(new_xml);

    while (attr_iter != NULL) {
        xmlAttr *new_attr = attr_iter;
        xml_private_t *p = attr_iter->_private;

        attr_iter = attr_iter->next;
        if (pcmk_is_set(p->flags, xpf_created)) {
            const char *attr_name = (const char *) new_attr->name;

            crm_trace("Created new attribute %s=%s in %s",
                      attr_name, crm_element_value(new_xml, attr_name),
                      new_xml->name);

            /* Check ACLs (we can't use the remove-then-create trick because it
             * would modify the attribute position).
             */
            if (pcmk__check_acl(new_xml, attr_name, xpf_acl_write)) {
                pcmk__mark_xml_attr_dirty(new_attr);
            } else {
                // Creation was not allowed, so remove the attribute
                xmlUnsetProp(new_xml, new_attr->name);
            }
        }
    }
}

static void
xml_diff_attrs(xmlNode *old_xml, xmlNode *new_xml)
{
    set_attrs_flag(new_xml, xpf_created); // cleared later if not really new
    xml_diff_old_attrs(old_xml, new_xml);
    mark_created_attrs(new_xml);
}

static void
mark_child_deleted(xmlNode *old_child, xmlNode *new_parent)
{
    // Re-create the child element so we can check ACLs
    xmlNode *candidate = add_node_copy(new_parent, old_child);

    // Clear flags on new child and its children
    reset_xml_node_flags(candidate);

    // Check whether ACLs allow the deletion
    pcmk__apply_acl(xmlDocGetRootElement(candidate->doc));

    // Remove the child again (which will track it in document's deleted_objs)
    free_xml_with_position(candidate,
                           pcmk__xml_position(old_child, xpf_skip));

    if (pcmk__xml_match(new_parent, old_child, true) == NULL) {
        pcmk__set_xml_flags((xml_private_t *) (old_child->_private), xpf_skip);
    }
}

static void
mark_child_moved(xmlNode *old_child, xmlNode *new_parent, xmlNode *new_child,
                 int p_old, int p_new)
{
    xml_private_t *p = new_child->_private;

    crm_trace("Child element %s with id='%s' moved from position %d to %d under %s",
              new_child->name, (ID(new_child)? ID(new_child) : "<no id>"),
              p_old, p_new, new_parent->name);
    mark_xml_node_dirty(new_parent);
    pcmk__set_xml_flags(p, xpf_moved);

    if (p_old > p_new) {
        p = old_child->_private;
    } else {
        p = new_child->_private;
    }
    pcmk__set_xml_flags(p, xpf_skip);
}

// Given original and new XML, mark new XML portions that have changed
static void
mark_xml_changes(xmlNode *old_xml, xmlNode *new_xml, bool check_top)
{
    xmlNode *cIter = NULL;
    xml_private_t *p = NULL;

    CRM_CHECK(new_xml != NULL, return);
    if (old_xml == NULL) {
        pcmk__mark_xml_created(new_xml);
        pcmk__apply_creation_acl(new_xml, check_top);
        return;
    }

    p = new_xml->_private;
    CRM_CHECK(p != NULL, return);

    if(p->flags & xpf_processed) {
        /* Avoid re-comparing nodes */
        return;
    }
    pcmk__set_xml_flags(p, xpf_processed);

    xml_diff_attrs(old_xml, new_xml);

    // Check for differences in the original children
    for (cIter = pcmk__xml_first_child(old_xml); cIter != NULL; ) {
        xmlNode *old_child = cIter;
        xmlNode *new_child = pcmk__xml_match(new_xml, cIter, true);

        cIter = pcmk__xml_next(cIter);
        if(new_child) {
            mark_xml_changes(old_child, new_child, TRUE);

        } else {
            mark_child_deleted(old_child, new_xml);
        }
    }

    // Check for moved or created children
    for (cIter = pcmk__xml_first_child(new_xml); cIter != NULL; ) {
        xmlNode *new_child = cIter;
        xmlNode *old_child = pcmk__xml_match(old_xml, cIter, true);

        cIter = pcmk__xml_next(cIter);
        if(old_child == NULL) {
            // This is a newly created child
            p = new_child->_private;
            pcmk__set_xml_flags(p, xpf_skip);
            mark_xml_changes(old_child, new_child, TRUE);

        } else {
            /* Check for movement, we already checked for differences */
            int p_new = pcmk__xml_position(new_child, xpf_skip);
            int p_old = pcmk__xml_position(old_child, xpf_skip);

            if(p_old != p_new) {
                mark_child_moved(old_child, new_xml, new_child, p_old, p_new);
            }
        }
    }
}

void
xml_calculate_significant_changes(xmlNode *old_xml, xmlNode *new_xml)
{
    pcmk__set_xml_doc_flag(new_xml, xpf_lazy);
    xml_calculate_changes(old_xml, new_xml);
}

void
xml_calculate_changes(xmlNode *old_xml, xmlNode *new_xml)
{
    CRM_CHECK(pcmk__str_eq(crm_element_name(old_xml), crm_element_name(new_xml), pcmk__str_casei),
              return);
    CRM_CHECK(pcmk__str_eq(ID(old_xml), ID(new_xml), pcmk__str_casei), return);

    if(xml_tracking_changes(new_xml) == FALSE) {
        xml_track_changes(new_xml, NULL, NULL, FALSE);
    }

    mark_xml_changes(old_xml, new_xml, FALSE);
}

gboolean
can_prune_leaf(xmlNode * xml_node)
{
    xmlNode *cIter = NULL;
    gboolean can_prune = TRUE;
    const char *name = crm_element_name(xml_node);

    if (pcmk__strcase_any_of(name, XML_TAG_RESOURCE_REF, XML_CIB_TAG_OBJ_REF,
                             XML_ACL_TAG_ROLE_REF, XML_ACL_TAG_ROLE_REFv1, NULL)) {
        return FALSE;
    }

    for (xmlAttrPtr a = pcmk__xe_first_attr(xml_node); a != NULL; a = a->next) {
        const char *p_name = (const char *) a->name;

        if (strcmp(p_name, XML_ATTR_ID) == 0) {
            continue;
        }
        can_prune = FALSE;
    }

    cIter = pcmk__xml_first_child(xml_node);
    while (cIter) {
        xmlNode *child = cIter;

        cIter = pcmk__xml_next(cIter);
        if (can_prune_leaf(child)) {
            free_xml(child);
        } else {
            can_prune = FALSE;
        }
    }
    return can_prune;
}

xmlNode *
pcmk__xc_match(xmlNode *root, xmlNode *search_comment, bool exact)
{
    xmlNode *a_child = NULL;
    int search_offset = pcmk__xml_position(search_comment, xpf_skip);

    CRM_CHECK(search_comment->type == XML_COMMENT_NODE, return NULL);

    for (a_child = pcmk__xml_first_child(root); a_child != NULL;
         a_child = pcmk__xml_next(a_child)) {
        if (exact) {
            int offset = pcmk__xml_position(a_child, xpf_skip);
            xml_private_t *p = a_child->_private;

            if (offset < search_offset) {
                continue;

            } else if (offset > search_offset) {
                return NULL;
            }

            if (pcmk_is_set(p->flags, xpf_skip)) {
                continue;
            }
        }

        if (a_child->type == XML_COMMENT_NODE
            && pcmk__str_eq((const char *)a_child->content, (const char *)search_comment->content, pcmk__str_casei)) {
            return a_child;

        } else if (exact) {
            return NULL;
        }
    }

    return NULL;
}

void
pcmk__xc_update(xmlNode *parent, xmlNode *target, xmlNode *update)
{
    CRM_CHECK(update != NULL, return);
    CRM_CHECK(update->type == XML_COMMENT_NODE, return);

    if (target == NULL) {
        target = pcmk__xc_match(parent, update, false);
    }

    if (target == NULL) {
        add_node_copy(parent, update);

    } else if (!pcmk__str_eq((const char *)target->content, (const char *)update->content, pcmk__str_casei)) {
        xmlFree(target->content);
        target->content = xmlStrdup(update->content);
    }
}

void
pcmk__xml_update(xmlNode *parent, xmlNode *target, xmlNode *update,
                 bool as_diff)
{
    xmlNode *a_child = NULL;
    const char *object_name = NULL,
               *object_href = NULL,
               *object_href_val = NULL;

#if XML_PARSER_DEBUG
    crm_log_xml_trace("update:", update);
    crm_log_xml_trace("target:", target);
#endif

    CRM_CHECK(update != NULL, return);

    if (update->type == XML_COMMENT_NODE) {
        pcmk__xc_update(parent, target, update);
        return;
    }

    object_name = crm_element_name(update);
    object_href_val = ID(update);
    if (object_href_val != NULL) {
        object_href = XML_ATTR_ID;
    } else {
        object_href_val = crm_element_value(update, XML_ATTR_IDREF);
        object_href = (object_href_val == NULL) ? NULL : XML_ATTR_IDREF;
    }

    CRM_CHECK(object_name != NULL, return);
    CRM_CHECK(target != NULL || parent != NULL, return);

    if (target == NULL) {
        target = pcmk__xe_match(parent, object_name,
                                object_href, object_href_val);
    }

    if (target == NULL) {
        target = create_xml_node(parent, object_name);
        CRM_CHECK(target != NULL, return);
#if XML_PARSER_DEBUG
        crm_trace("Added  <%s%s%s%s%s/>", crm_str(object_name),
                  object_href ? " " : "",
                  object_href ? object_href : "",
                  object_href ? "=" : "",
                  object_href ? object_href_val : "");

    } else {
        crm_trace("Found node <%s%s%s%s%s/> to update", crm_str(object_name),
                  object_href ? " " : "",
                  object_href ? object_href : "",
                  object_href ? "=" : "",
                  object_href ? object_href_val : "");
#endif
    }

    CRM_CHECK(pcmk__str_eq(crm_element_name(target), crm_element_name(update),
                           pcmk__str_casei),
              return);

    if (as_diff == FALSE) {
        /* So that expand_plus_plus() gets called */
        copy_in_properties(target, update);

    } else {
        /* No need for expand_plus_plus(), just raw speed */
        for (xmlAttrPtr a = pcmk__xe_first_attr(update); a != NULL;
             a = a->next) {
            const char *p_value = pcmk__xml_attr_value(a);

            /* Remove it first so the ordering of the update is preserved */
            xmlUnsetProp(target, a->name);
            xmlSetProp(target, a->name, (pcmkXmlStr) p_value);
        }
    }

    for (a_child = pcmk__xml_first_child(update); a_child != NULL;
         a_child = pcmk__xml_next(a_child)) {
#if XML_PARSER_DEBUG
        crm_trace("Updating child <%s%s%s%s%s/>", crm_str(object_name),
                  object_href ? " " : "",
                  object_href ? object_href : "",
                  object_href ? "=" : "",
                  object_href ? object_href_val : "");
#endif
        pcmk__xml_update(target, NULL, a_child, as_diff);
    }

#if XML_PARSER_DEBUG
    crm_trace("Finished with <%s%s%s%s%s/>", crm_str(object_name),
              object_href ? " " : "",
              object_href ? object_href : "",
              object_href ? "=" : "",
              object_href ? object_href_val : "");
#endif
}

gboolean
update_xml_child(xmlNode * child, xmlNode * to_update)
{
    gboolean can_update = TRUE;
    xmlNode *child_of_child = NULL;

    CRM_CHECK(child != NULL, return FALSE);
    CRM_CHECK(to_update != NULL, return FALSE);

    if (!pcmk__str_eq(crm_element_name(to_update), crm_element_name(child), pcmk__str_casei)) {
        can_update = FALSE;

    } else if (!pcmk__str_eq(ID(to_update), ID(child), pcmk__str_casei)) {
        can_update = FALSE;

    } else if (can_update) {
#if XML_PARSER_DEBUG
        crm_log_xml_trace(child, "Update match found...");
#endif
        pcmk__xml_update(NULL, child, to_update, false);
    }

    for (child_of_child = pcmk__xml_first_child(child); child_of_child != NULL;
         child_of_child = pcmk__xml_next(child_of_child)) {
        /* only update the first one */
        if (can_update) {
            break;
        }
        can_update = update_xml_child(child_of_child, to_update);
    }

    return can_update;
}

int
find_xml_children(xmlNode ** children, xmlNode * root,
                  const char *tag, const char *field, const char *value, gboolean search_matches)
{
    int match_found = 0;

    CRM_CHECK(root != NULL, return FALSE);
    CRM_CHECK(children != NULL, return FALSE);

    if (tag != NULL && !pcmk__str_eq(tag, crm_element_name(root), pcmk__str_casei)) {

    } else if (value != NULL && !pcmk__str_eq(value, crm_element_value(root, field), pcmk__str_casei)) {

    } else {
        if (*children == NULL) {
            *children = create_xml_node(NULL, __func__);
        }
        add_node_copy(*children, root);
        match_found = 1;
    }

    if (search_matches || match_found == 0) {
        xmlNode *child = NULL;

        for (child = pcmk__xml_first_child(root); child != NULL;
             child = pcmk__xml_next(child)) {
            match_found += find_xml_children(children, child, tag, field, value, search_matches);
        }
    }

    return match_found;
}

gboolean
replace_xml_child(xmlNode * parent, xmlNode * child, xmlNode * update, gboolean delete_only)
{
    gboolean can_delete = FALSE;
    xmlNode *child_of_child = NULL;

    const char *up_id = NULL;
    const char *child_id = NULL;
    const char *right_val = NULL;

    CRM_CHECK(child != NULL, return FALSE);
    CRM_CHECK(update != NULL, return FALSE);

    up_id = ID(update);
    child_id = ID(child);

    if (up_id == NULL || (child_id && strcmp(child_id, up_id) == 0)) {
        can_delete = TRUE;
    }
    if (!pcmk__str_eq(crm_element_name(update), crm_element_name(child), pcmk__str_casei)) {
        can_delete = FALSE;
    }
    if (can_delete && delete_only) {
        for (xmlAttrPtr a = pcmk__xe_first_attr(update); a != NULL;
             a = a->next) {
            const char *p_name = (const char *) a->name;
            const char *p_value = pcmk__xml_attr_value(a);

            right_val = crm_element_value(child, p_name);
            if (!pcmk__str_eq(p_value, right_val, pcmk__str_casei)) {
                can_delete = FALSE;
            }
        }
    }

    if (can_delete && parent != NULL) {
        crm_log_xml_trace(child, "Delete match found...");
        if (delete_only || update == NULL) {
            free_xml(child);

        } else {
            xmlNode *tmp = copy_xml(update);
            xmlDoc *doc = tmp->doc;
            xmlNode *old = NULL;

            xml_accept_changes(tmp);
            old = xmlReplaceNode(child, tmp);

            if(xml_tracking_changes(tmp)) {
                /* Replaced sections may have included relevant ACLs */
                pcmk__apply_acl(tmp);
            }

            xml_calculate_changes(old, tmp);
            xmlDocSetRootElement(doc, old);
            free_xml(old);
        }
        child = NULL;
        return TRUE;

    } else if (can_delete) {
        crm_log_xml_debug(child, "Cannot delete the search root");
        can_delete = FALSE;
    }

    child_of_child = pcmk__xml_first_child(child);
    while (child_of_child) {
        xmlNode *next = pcmk__xml_next(child_of_child);

        can_delete = replace_xml_child(child, child_of_child, update, delete_only);

        /* only delete the first one */
        if (can_delete) {
            child_of_child = NULL;
        } else {
            child_of_child = next;
        }
    }

    return can_delete;
}

xmlNode *
sorted_xml(xmlNode *input, xmlNode *parent, gboolean recursive)
{
    xmlNode *child = NULL;
    GSList *nvpairs = NULL;
    xmlNode *result = NULL;
    const char *name = NULL;

    CRM_CHECK(input != NULL, return NULL);

    name = crm_element_name(input);
    CRM_CHECK(name != NULL, return NULL);

    result = create_xml_node(parent, name);
    nvpairs = pcmk_xml_attrs2nvpairs(input);
    nvpairs = pcmk_sort_nvpairs(nvpairs);
    pcmk_nvpairs2xml_attrs(nvpairs, result);
    pcmk_free_nvpairs(nvpairs);

    for (child = pcmk__xml_first_child(input); child != NULL;
         child = pcmk__xml_next(child)) {

        if (recursive) {
            sorted_xml(child, result, recursive);
        } else {
            add_node_copy(result, child);
        }
    }

    return result;
}

xmlNode *
first_named_child(const xmlNode *parent, const char *name)
{
    xmlNode *match = NULL;

    for (match = pcmk__xe_first_child(parent); match != NULL;
         match = pcmk__xe_next(match)) {
        /*
         * name == NULL gives first child regardless of name; this is
         * semantically incorrect in this function, but may be necessary
         * due to prior use of xml_child_iter_filter
         */
        if (pcmk__str_eq(name, (const char *)match->name, pcmk__str_null_matches)) {
            return match;
        }
    }
    return NULL;
}

xmlNode *
crm_next_same_xml(const xmlNode *sibling)
{
    xmlNode *match = pcmk__xe_next(sibling);
    const char *name = crm_element_name(sibling);

    while (match != NULL) {
        if (!strcmp(crm_element_name(match), name)) {
            return match;
        }
        match = pcmk__xe_next(match);
    }
    return NULL;
}

void
crm_xml_init(void)
{
    static bool init = TRUE;

    if(init) {
        init = FALSE;
        /* The default allocator XML_BUFFER_ALLOC_EXACT does far too many
         * pcmk__realloc()s and it can take upwards of 18 seconds (yes, seconds)
         * to dump a 28kb tree which XML_BUFFER_ALLOC_DOUBLEIT can do in
         * less than 1 second.
         */
        xmlSetBufferAllocationScheme(XML_BUFFER_ALLOC_DOUBLEIT);

        /* Populate and free the _private field when nodes are created and destroyed */
        xmlDeregisterNodeDefault(free_private_data);
        xmlRegisterNodeDefault(new_private_data);

        crm_schema_init();
    }
}

void
crm_xml_cleanup(void)
{
    crm_info("Cleaning up memory from libxml2");
    crm_schema_cleanup();
    xmlCleanupParser();
}

#define XPATH_MAX 512

xmlNode *
expand_idref(xmlNode * input, xmlNode * top)
{
    const char *tag = NULL;
    const char *ref = NULL;
    xmlNode *result = input;

    if (result == NULL) {
        return NULL;

    } else if (top == NULL) {
        top = input;
    }

    tag = crm_element_name(result);
    ref = crm_element_value(result, XML_ATTR_IDREF);

    if (ref != NULL) {
        char *xpath_string = crm_strdup_printf("//%s[@id='%s']", tag, ref);

        result = get_xpath_object(xpath_string, top, LOG_ERR);
        if (result == NULL) {
            char *nodePath = (char *)xmlGetNodePath(top);

            crm_err("No match for %s found in %s: Invalid configuration", xpath_string,
                    crm_str(nodePath));
            free(nodePath);
        }
        free(xpath_string);
    }
    return result;
}

void
crm_destroy_xml(gpointer data)
{
    free_xml(data);
}

char *
pcmk__xml_artefact_root(enum pcmk__xml_artefact_ns ns)
{
    static const char *base = NULL;
    char *ret = NULL;

    if (base == NULL) {
        base = getenv("PCMK_schema_directory");
    }
    if (pcmk__str_empty(base)) {
        base = CRM_SCHEMA_DIRECTORY;
    }

    switch (ns) {
        case pcmk__xml_artefact_ns_legacy_rng:
        case pcmk__xml_artefact_ns_legacy_xslt:
            ret = strdup(base);
            break;
        case pcmk__xml_artefact_ns_base_rng:
        case pcmk__xml_artefact_ns_base_xslt:
            ret = crm_strdup_printf("%s/base", base);
            break;
        default:
            crm_err("XML artefact family specified as %u not recognized", ns);
    }
    return ret;
}

char *
pcmk__xml_artefact_path(enum pcmk__xml_artefact_ns ns, const char *filespec)
{
    char *base = pcmk__xml_artefact_root(ns), *ret = NULL;

    switch (ns) {
        case pcmk__xml_artefact_ns_legacy_rng:
        case pcmk__xml_artefact_ns_base_rng:
            ret = crm_strdup_printf("%s/%s.rng", base, filespec);
            break;
        case pcmk__xml_artefact_ns_legacy_xslt:
        case pcmk__xml_artefact_ns_base_xslt:
            ret = crm_strdup_printf("%s/%s.xsl", base, filespec);
            break;
        default:
            crm_err("XML artefact family specified as %u not recognized", ns);
    }
    free(base);

    return ret;
}

void
pcmk__xe_set_propv(xmlNodePtr node, va_list pairs)
{
    while (true) {
        const char *name, *value;

        name = va_arg(pairs, const char *);
        if (name == NULL) {
            return;
        }

        value = va_arg(pairs, const char *);
        if (value == NULL) {
            return;
        }

        crm_xml_add(node, name, value);
    }
}

void
pcmk__xe_set_props(xmlNodePtr node, ...)
{
    va_list pairs;
    va_start(pairs, node);
    pcmk__xe_set_propv(node, pairs);
    va_end(pairs);
}

// Deprecated functions kept only for backward API compatibility

#include <crm/common/xml_compat.h>

xmlNode *
find_entity(xmlNode *parent, const char *node_name, const char *id)
{
    return pcmk__xe_match(parent, node_name,
                          ((id == NULL)? id : XML_ATTR_ID), id);
}

// End deprecated API