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libxml reports some errors (like invalid xmlns attributes) via the error handler hook, but still returns a success indicator to the library caller. This causes us to miss some errors that are important to report. Since the "generic" error handler hook doesn't know whether the message it's getting is for an error, warning, or notice, stop using that and instead start using the "structured" error handler hook, which gets enough information to be useful. While at it, arrange to save and restore the error handler hook setting in each libxml-using function, rather than assuming we can set and forget the hook. This should improve the odds of working nicely with third-party libraries that also use libxml. In passing, volatile-ize some local variables that get modified within PG_TRY blocks. I noticed this while testing with an older gcc version than I'd previously tried to compile xml.c with. Florian Pflug and Tom Lane, with extensive review/testing by Noah Misch
215 lines
4.4 KiB
C
215 lines
4.4 KiB
C
/*
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* contrib/xml2/xslt_proc.c
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*
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* XSLT processing functions (requiring libxslt)
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*
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* John Gray, for Torchbox 2003-04-01
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*/
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#include "postgres.h"
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#include "executor/spi.h"
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#include "fmgr.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "utils/builtins.h"
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#include "utils/xml.h"
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#ifdef USE_LIBXSLT
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/* libxml includes */
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#include <libxml/xpath.h>
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#include <libxml/tree.h>
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#include <libxml/xmlmemory.h>
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/* libxslt includes */
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#include <libxslt/xslt.h>
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#include <libxslt/xsltInternals.h>
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#include <libxslt/transform.h>
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#include <libxslt/xsltutils.h>
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#endif /* USE_LIBXSLT */
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/* externally accessible functions */
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Datum xslt_process(PG_FUNCTION_ARGS);
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#ifdef USE_LIBXSLT
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/* declarations to come from xpath.c */
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extern PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
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/* local defs */
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static const char **parse_params(text *paramstr);
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#endif /* USE_LIBXSLT */
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PG_FUNCTION_INFO_V1(xslt_process);
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Datum
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xslt_process(PG_FUNCTION_ARGS)
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{
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#ifdef USE_LIBXSLT
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text *doct = PG_GETARG_TEXT_P(0);
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text *ssheet = PG_GETARG_TEXT_P(1);
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text *paramstr;
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const char **params;
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PgXmlErrorContext *xmlerrcxt;
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volatile xsltStylesheetPtr stylesheet = NULL;
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volatile xmlDocPtr doctree = NULL;
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volatile xmlDocPtr restree = NULL;
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volatile xmlDocPtr ssdoc = NULL;
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volatile int resstat = -1;
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xmlChar *resstr = NULL;
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int reslen = 0;
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if (fcinfo->nargs == 3)
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{
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paramstr = PG_GETARG_TEXT_P(2);
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params = parse_params(paramstr);
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}
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else
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{
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/* No parameters */
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params = (const char **) palloc(sizeof(char *));
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params[0] = NULL;
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}
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/* Setup parser */
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xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
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PG_TRY();
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{
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/* Check to see if document is a file or a literal */
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if (VARDATA(doct)[0] == '<')
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doctree = xmlParseMemory((char *) VARDATA(doct), VARSIZE(doct) - VARHDRSZ);
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else
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doctree = xmlParseFile(text_to_cstring(doct));
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if (doctree == NULL)
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xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
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"error parsing XML document");
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/* Same for stylesheet */
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if (VARDATA(ssheet)[0] == '<')
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{
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ssdoc = xmlParseMemory((char *) VARDATA(ssheet),
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VARSIZE(ssheet) - VARHDRSZ);
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if (ssdoc == NULL)
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xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
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"error parsing stylesheet as XML document");
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stylesheet = xsltParseStylesheetDoc(ssdoc);
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}
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else
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stylesheet = xsltParseStylesheetFile((xmlChar *) text_to_cstring(ssheet));
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if (stylesheet == NULL)
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xml_ereport(xmlerrcxt, ERROR, ERRCODE_EXTERNAL_ROUTINE_EXCEPTION,
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"failed to parse stylesheet");
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restree = xsltApplyStylesheet(stylesheet, doctree, params);
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resstat = xsltSaveResultToString(&resstr, &reslen, restree, stylesheet);
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}
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PG_CATCH();
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{
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if (stylesheet != NULL)
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xsltFreeStylesheet(stylesheet);
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if (restree != NULL)
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xmlFreeDoc(restree);
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if (doctree != NULL)
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xmlFreeDoc(doctree);
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xsltCleanupGlobals();
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pg_xml_done(xmlerrcxt, true);
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PG_RE_THROW();
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}
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PG_END_TRY();
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xsltFreeStylesheet(stylesheet);
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xmlFreeDoc(restree);
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xmlFreeDoc(doctree);
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xsltCleanupGlobals();
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pg_xml_done(xmlerrcxt, false);
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if (resstat < 0)
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PG_RETURN_NULL();
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PG_RETURN_TEXT_P(cstring_to_text_with_len((char *) resstr, reslen));
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#else /* !USE_LIBXSLT */
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("xslt_process() is not available without libxslt")));
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PG_RETURN_NULL();
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#endif /* USE_LIBXSLT */
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}
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#ifdef USE_LIBXSLT
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static const char **
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parse_params(text *paramstr)
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{
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char *pos;
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char *pstr;
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char *nvsep = "=";
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char *itsep = ",";
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const char **params;
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int max_params;
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int nparams;
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pstr = text_to_cstring(paramstr);
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max_params = 20; /* must be even! */
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params = (const char **) palloc((max_params + 1) * sizeof(char *));
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nparams = 0;
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pos = pstr;
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while (*pos != '\0')
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{
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if (nparams >= max_params)
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{
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max_params *= 2;
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params = (const char **) repalloc(params,
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(max_params + 1) * sizeof(char *));
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}
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params[nparams++] = pos;
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pos = strstr(pos, nvsep);
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if (pos != NULL)
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{
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*pos = '\0';
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pos++;
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}
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else
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{
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/* No equal sign, so ignore this "parameter" */
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nparams--;
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break;
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}
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/* since max_params is even, we still have nparams < max_params */
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params[nparams++] = pos;
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pos = strstr(pos, itsep);
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if (pos != NULL)
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{
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*pos = '\0';
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pos++;
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}
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else
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break;
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}
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/* Add the terminator marker; we left room for it in the palloc's */
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params[nparams] = NULL;
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return params;
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}
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#endif /* USE_LIBXSLT */
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