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/*
* Copyright 2004-2024 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 <string.h>
#include <crm/common/xml.h>
#include <crm/common/xml_internal.h>
#include "crmcommon_private.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(const xmlNode *xml_top, const char *path)
{
xmlXPathObjectPtr xpathObj = NULL;
xmlXPathContextPtr xpathCtx = NULL;
const xmlChar *xpathExpr = (pcmkXmlStr) path;
CRM_CHECK(path != NULL, return NULL);
CRM_CHECK(xml_top != NULL, return NULL);
CRM_CHECK(strlen(path) > 0, return NULL);
xpathCtx = xmlXPathNewContext(xml_top->doc);
pcmk__mem_assert(xpathCtx);
xpathObj = xmlXPathEvalExpression(xpathExpr, xpathCtx);
xmlXPathFreeContext(xpathCtx);
return xpathObj;
}
/*!
* \brief Run a supplied function for each result of an xpath search
*
* \param[in,out] 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(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) {
if (error_level < LOG_NEVER) {
do_crm_log(error_level, "No match for %s in %s",
xpath, pcmk__s(nodePath, "unknown path"));
crm_log_xml_explicit(xml_obj, "Unexpected Input");
}
} else if (max > 1) {
if (error_level < LOG_NEVER) {
int lpc = 0;
do_crm_log(error_level, "Too many matches for %s in %s",
xpath, pcmk__s(nodePath, "unknown path"));
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,
pcmk__s(matchNodePath, "unrecognizable match"));
free(matchNodePath);
}
}
crm_log_xml_explicit(xml_obj, "Bad Input");
}
} else {
result = getXpathResult(xpathObj, 0);
}
freeXpathObject(xpathObj);
free(nodePath);
return result;
}
/*!
* \internal
* \brief Get an XPath string that matches an XML element as closely as possible
*
* \param[in] xml The XML element for which to build an XPath string
*
* \return A \p GString that matches \p xml, or \p NULL if \p xml is \p NULL.
*
* \note The caller is responsible for freeing the string using
* \p g_string_free().
*/
GString *
pcmk__element_xpath(const xmlNode *xml)
{
const xmlNode *parent = NULL;
GString *xpath = NULL;
const char *id = NULL;
if (xml == NULL) {
return NULL;
}
parent = xml->parent;
xpath = pcmk__element_xpath(parent);
if (xpath == NULL) {
xpath = g_string_sized_new(256);
}
// Build xpath like "/" -> "/cib" -> "/cib/configuration"
if (parent == NULL) {
g_string_append_c(xpath, '/');
} else if (parent->parent == NULL) {
g_string_append(xpath, (const gchar *) xml->name);
} else {
pcmk__g_strcat(xpath, "/", (const char *) xml->name, NULL);
}
id = pcmk__xe_id(xml);
if (id != NULL) {
pcmk__g_strcat(xpath, "[@" PCMK_XA_ID "='", id, "']", NULL);
}
return xpath;
}
char *
pcmk__xpath_node_id(const char *xpath, const char *node)
{
char *retval = NULL;
char *patt = NULL;
char *start = NULL;
char *end = NULL;
if (node == NULL || xpath == NULL) {
return retval;
}
patt = crm_strdup_printf("/%s[@" PCMK_XA_ID "=", node);
start = strstr(xpath, patt);
if (!start) {
free(patt);
return retval;
}
start += strlen(patt);
start++;
end = strstr(start, "\'");
CRM_ASSERT(end);
retval = strndup(start, end-start);
free(patt);
return retval;
}
static int
output_attr_child(xmlNode *child, void *userdata)
{
pcmk__output_t *out = userdata;
out->info(out, " Value: %s \t(id=%s)",
crm_element_value(child, PCMK_XA_VALUE),
pcmk__s(pcmk__xe_id(child), "<none>"));
return pcmk_rc_ok;
}
void
pcmk__warn_multiple_name_matches(pcmk__output_t *out, xmlNode *search,
const char *name)
{
if (out == NULL || name == NULL || search == NULL ||
search->children == NULL) {
return;
}
out->info(out, "Multiple attributes match " PCMK_XA_NAME "=%s", name);
pcmk__xe_foreach_child(search, NULL, output_attr_child, out);
}

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