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/*
* contrib/xml2/xslt_proc.c
*
* XSLT processing functions (requiring libxslt)
*
* John Gray, for Torchbox 2003-04-01
*/
#include "postgres.h"
#include "executor/spi.h"
#include "fmgr.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/xml.h"
#ifdef USE_LIBXSLT
/* libxml includes */
#include <libxml/xpath.h>
#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
/* libxslt includes */
#include <libxslt/xslt.h>
#include <libxslt/xsltInternals.h>
#include <libxslt/security.h>
#include <libxslt/transform.h>
#include <libxslt/xsltutils.h>
#endif /* USE_LIBXSLT */
#ifdef USE_LIBXSLT
/* declarations to come from xpath.c */
extern PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
/* local defs */
static const char **parse_params(text *paramstr);
#endif /* USE_LIBXSLT */
PG_FUNCTION_INFO_V1(xslt_process);
Datum
xslt_process(PG_FUNCTION_ARGS)
{
#ifdef USE_LIBXSLT
text *doct = PG_GETARG_TEXT_PP(0);
text *ssheet = PG_GETARG_TEXT_PP(1);
text *result;
text *paramstr;
const char **params;
PgXmlErrorContext *xmlerrcxt;
volatile xsltStylesheetPtr stylesheet = NULL;
volatile xmlDocPtr doctree = NULL;
volatile xmlDocPtr restree = NULL;
volatile xsltSecurityPrefsPtr xslt_sec_prefs = NULL;
volatile xsltTransformContextPtr xslt_ctxt = NULL;
volatile int resstat = -1;
xmlChar *resstr = NULL;
int reslen = 0;
if (fcinfo->nargs == 3)
{
paramstr = PG_GETARG_TEXT_PP(2);
params = parse_params(paramstr);
}
else
{
/* No parameters */
params = (const char **) palloc(sizeof(char *));
params[0] = NULL;
}
/* Setup parser */
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
PG_TRY();
{
xmlDocPtr ssdoc;
bool xslt_sec_prefs_error;
/* Parse document */
doctree = xmlParseMemory((char *) VARDATA_ANY(doct),
VARSIZE_ANY_EXHDR(doct));
if (doctree == NULL)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"error parsing XML document");
/* Same for stylesheet */
ssdoc = xmlParseMemory((char *) VARDATA_ANY(ssheet),
VARSIZE_ANY_EXHDR(ssheet));
if (ssdoc == NULL)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"error parsing stylesheet as XML document");
/* After this call we need not free ssdoc separately */
stylesheet = xsltParseStylesheetDoc(ssdoc);
if (stylesheet == NULL)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"failed to parse stylesheet");
xslt_ctxt = xsltNewTransformContext(stylesheet, doctree);
xslt_sec_prefs_error = false;
if ((xslt_sec_prefs = xsltNewSecurityPrefs()) == NULL)
xslt_sec_prefs_error = true;
if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_FILE,
xsltSecurityForbid) != 0)
xslt_sec_prefs_error = true;
if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_FILE,
xsltSecurityForbid) != 0)
xslt_sec_prefs_error = true;
if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_CREATE_DIRECTORY,
xsltSecurityForbid) != 0)
xslt_sec_prefs_error = true;
if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_READ_NETWORK,
xsltSecurityForbid) != 0)
xslt_sec_prefs_error = true;
if (xsltSetSecurityPrefs(xslt_sec_prefs, XSLT_SECPREF_WRITE_NETWORK,
xsltSecurityForbid) != 0)
xslt_sec_prefs_error = true;
if (xsltSetCtxtSecurityPrefs(xslt_sec_prefs, xslt_ctxt) != 0)
xslt_sec_prefs_error = true;
if (xslt_sec_prefs_error)
ereport(ERROR,
(errmsg("could not set libxslt security preferences")));
restree = xsltApplyStylesheetUser(stylesheet, doctree, params,
NULL, NULL, xslt_ctxt);
if (restree == NULL)
xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
"failed to apply stylesheet");
resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
}
PG_CATCH();
{
if (restree != NULL)
xmlFreeDoc(restree);
if (xslt_ctxt != NULL)
xsltFreeTransformContext(xslt_ctxt);
if (xslt_sec_prefs != NULL)
xsltFreeSecurityPrefs(xslt_sec_prefs);
if (stylesheet != NULL)
xsltFreeStylesheet(stylesheet);
if (doctree != NULL)
xmlFreeDoc(doctree);
xsltCleanupGlobals();
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xmlFreeDoc(restree);
xsltFreeTransformContext(xslt_ctxt);
xsltFreeSecurityPrefs(xslt_sec_prefs);
xsltFreeStylesheet(stylesheet);
xmlFreeDoc(doctree);
xsltCleanupGlobals();
pg_xml_done(xmlerrcxt, false);
/* XXX this is pretty dubious, really ought to throw error instead */
if (resstat < 0)
PG_RETURN_NULL();
result = cstring_to_text_with_len((char *) resstr, reslen);
if (resstr)
xmlFree(resstr);
PG_RETURN_TEXT_P(result);
#else /* !USE_LIBXSLT */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("xslt_process() is not available without libxslt")));
PG_RETURN_NULL();
#endif /* USE_LIBXSLT */
}
#ifdef USE_LIBXSLT
static const char **
parse_params(text *paramstr)
{
char *pos;
char *pstr;
char *nvsep = "=";
char *itsep = ",";
const char **params;
int max_params;
int nparams;
pstr = text_to_cstring(paramstr);
max_params = 20; /* must be even! */
params = (const char **) palloc((max_params + 1) * sizeof(char *));
nparams = 0;
pos = pstr;
while (*pos != '\0')
{
if (nparams >= max_params)
{
max_params *= 2;
params = (const char **) repalloc(params,
(max_params + 1) * sizeof(char *));
}
params[nparams++] = pos;
pos = strstr(pos, nvsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
else
{
/* No equal sign, so ignore this "parameter" */
nparams--;
break;
}
/* since max_params is even, we still have nparams < max_params */
params[nparams++] = pos;
pos = strstr(pos, itsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
else
break;
}
/* Add the terminator marker; we left room for it in the palloc's */
params[nparams] = NULL;
return params;
}
#endif /* USE_LIBXSLT */
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