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/*
* Copyright (C) 2004 Andrew Beekhof <andrew@beekhof.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <crm_internal.h>
#include <stdio.h>
#include <string.h>
/*
* From xpath2.c
*
* All the elements returned by an XPath query are pointers to
* elements from the tree *except* namespace nodes where the XPath
* semantic is different from the implementation in libxml2 tree.
* As a result when a returned node set is freed when
* xmlXPathFreeObject() is called, that routine must check the
* element type. But node from the returned set may have been removed
* by xmlNodeSetContent() resulting in access to freed data.
*
* This can be exercised by running
* valgrind xpath2 test3.xml '//discarded' discarded
*
* There is 2 ways around it:
* - make a copy of the pointers to the nodes from the result set
* then call xmlXPathFreeObject() and then modify the nodes
* or
* - remove the references from the node set, if they are not
namespace nodes, before calling xmlXPathFreeObject().
*/
void
freeXpathObject(xmlXPathObjectPtr xpathObj)
{
int lpc, max = numXpathResults(xpathObj);
if (xpathObj == NULL) {
return;
}
for (lpc = 0; lpc < max; lpc++) {
if (xpathObj->nodesetval->nodeTab[lpc] && xpathObj->nodesetval->nodeTab[lpc]->type != XML_NAMESPACE_DECL) {
xpathObj->nodesetval->nodeTab[lpc] = NULL;
}
}
/* _Now_ it's safe to free it */
xmlXPathFreeObject(xpathObj);
}
xmlNode *
getXpathResult(xmlXPathObjectPtr xpathObj, int index)
{
xmlNode *match = NULL;
int max = numXpathResults(xpathObj);
CRM_CHECK(index >= 0, return NULL);
CRM_CHECK(xpathObj != NULL, return NULL);
if (index >= max) {
crm_err("Requested index %d of only %d items", index, max);
return NULL;
} else if(xpathObj->nodesetval->nodeTab[index] == NULL) {
/* Previously requested */
return NULL;
}
match = xpathObj->nodesetval->nodeTab[index];
CRM_CHECK(match != NULL, return NULL);
if (xpathObj->nodesetval->nodeTab[index]->type != XML_NAMESPACE_DECL) {
/* See the comment for freeXpathObject() */
xpathObj->nodesetval->nodeTab[index] = NULL;
}
if (match->type == XML_DOCUMENT_NODE) {
/* Will happen if section = '/' */
match = match->children;
} else if (match->type != XML_ELEMENT_NODE
&& match->parent && match->parent->type == XML_ELEMENT_NODE) {
/* Return the parent instead */
match = match->parent;
} else if (match->type != XML_ELEMENT_NODE) {
/* We only support searching nodes */
crm_err("We only support %d not %d", XML_ELEMENT_NODE, match->type);
match = NULL;
}
return match;
}
void
dedupXpathResults(xmlXPathObjectPtr xpathObj)
{
int lpc, max = numXpathResults(xpathObj);
if (xpathObj == NULL) {
return;
}
for (lpc = 0; lpc < max; lpc++) {
xmlNode *xml = NULL;
gboolean dedup = FALSE;
if (xpathObj->nodesetval->nodeTab[lpc] == NULL) {
continue;
}
xml = xpathObj->nodesetval->nodeTab[lpc]->parent;
for (; xml; xml = xml->parent) {
int lpc2 = 0;
for (lpc2 = 0; lpc2 < max; lpc2++) {
if (xpathObj->nodesetval->nodeTab[lpc2] == xml) {
xpathObj->nodesetval->nodeTab[lpc] = NULL;
dedup = TRUE;
break;
}
}
if (dedup) {
break;
}
}
}
}
/* the caller needs to check if the result contains a xmlDocPtr or xmlNodePtr */
xmlXPathObjectPtr
xpath_search(xmlNode * xml_top, const char *path)
{
xmlDocPtr doc = NULL;
xmlXPathObjectPtr xpathObj = NULL;
xmlXPathContextPtr xpathCtx = NULL;
const xmlChar *xpathExpr = (const xmlChar *)path;
CRM_CHECK(path != NULL, return NULL);
CRM_CHECK(xml_top != NULL, return NULL);
CRM_CHECK(strlen(path) > 0, return NULL);
doc = getDocPtr(xml_top);
xpathCtx = xmlXPathNewContext(doc);
CRM_ASSERT(xpathCtx != NULL);
xpathObj = xmlXPathEvalExpression(xpathExpr, xpathCtx);
xmlXPathFreeContext(xpathCtx);
return xpathObj;
}
/*!
* \brief Run a supplied function for each result of an xpath search
*
* \param[in] xml XML to search
* \param[in] xpath XPath search string
* \param[in] helper Function to call for each result
* \param[in/out] user_data Data to pass to supplied function
*
* \note The helper function will be passed the XML node of the result,
* and the supplied user_data. This function does not otherwise
* use user_data.
*/
void
crm_foreach_xpath_result(xmlNode *xml, const char *xpath,
void (*helper)(xmlNode*, void*), void *user_data)
{
xmlXPathObjectPtr xpathObj = xpath_search(xml, xpath);
int nresults = numXpathResults(xpathObj);
int i;
for (i = 0; i < nresults; i++) {
xmlNode *result = getXpathResult(xpathObj, i);
CRM_LOG_ASSERT(result != NULL);
if (result) {
(*helper)(result, user_data);
}
}
freeXpathObject(xpathObj);
}
xmlNode *
get_xpath_object_relative(const char *xpath, xmlNode * xml_obj, int error_level)
{
int len = 0;
xmlNode *result = NULL;
char *xpath_full = NULL;
char *xpath_prefix = NULL;
if (xml_obj == NULL || xpath == NULL) {
return NULL;
}
xpath_prefix = (char *)xmlGetNodePath(xml_obj);
len = strlen(xpath_prefix) + strlen(xpath) + 1;
xpath_full = malloc(len);
strcpy(xpath_full, xpath_prefix);
strcat(xpath_full, xpath);
result = get_xpath_object(xpath_full, xml_obj, error_level);
free(xpath_prefix);
free(xpath_full);
return result;
}
xmlNode *
get_xpath_object(const char *xpath, xmlNode * xml_obj, int error_level)
{
int max;
xmlNode *result = NULL;
xmlXPathObjectPtr xpathObj = NULL;
char *nodePath = NULL;
char *matchNodePath = NULL;
if (xpath == NULL) {
return xml_obj; /* or return NULL? */
}
xpathObj = xpath_search(xml_obj, xpath);
nodePath = (char *)xmlGetNodePath(xml_obj);
max = numXpathResults(xpathObj);
if (max < 1) {
do_crm_log(error_level, "No match for %s in %s", xpath, crm_str(nodePath));
crm_log_xml_explicit(xml_obj, "Unexpected Input");
} else if (max > 1) {
int lpc = 0;
do_crm_log(error_level, "Too many matches for %s in %s", xpath, crm_str(nodePath));
for (lpc = 0; lpc < max; lpc++) {
xmlNode *match = getXpathResult(xpathObj, lpc);
CRM_LOG_ASSERT(match != NULL);
if(match != NULL) {
matchNodePath = (char *)xmlGetNodePath(match);
do_crm_log(error_level, "%s[%d] = %s", xpath, lpc, crm_str(matchNodePath));
free(matchNodePath);
}
}
crm_log_xml_explicit(xml_obj, "Bad Input");
} else {
result = getXpathResult(xpathObj, 0);
}
freeXpathObject(xpathObj);
free(nodePath);
return result;
}

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