From 19749fb0cf16dbb3a3e71b0c387edef907ea5d6b Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Sat, 6 Jan 2007 19:18:36 +0000
Subject: [PATCH] Replace xmlroot with a properly functioning version that
parses the value, sets the items, and serializes the value back (rather than
adding an arbitrary number of XML preambles as before).
The libxml memory management via palloc had to be disabled because it
crashes when libxml tries to access memory that was helpfully freed
earlier by PostgreSQL. This needs further thought.
---
src/backend/utils/adt/xml.c | 90 +++++++++++++++++++++--------
src/test/regress/expected/xml.out | 32 +++++++++-
src/test/regress/expected/xml_1.out | 6 ++
src/test/regress/sql/xml.sql | 3 +
4 files changed, 103 insertions(+), 28 deletions(-)
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 6771360c48a..ab929eed647 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.10 2007/01/05 22:19:42 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.11 2007/01/06 19:18:36 petere Exp $
*
*-------------------------------------------------------------------------
*/
@@ -31,6 +31,7 @@
#include <libxml/tree.h>
#include <libxml/uri.h>
#include <libxml/xmlerror.h>
+#include <libxml/xmlsave.h>
#endif /* USE_LIBXML */
#include "fmgr.h"
@@ -49,10 +50,12 @@
static StringInfo xml_err_buf = NULL;
static void xml_init(void);
+#ifdef NOT_USED
static void *xml_palloc(size_t size);
static void *xml_repalloc(void *ptr, size_t size);
static void xml_pfree(void *ptr);
static char *xml_pstrdup(const char *string);
+#endif
static void xml_ereport(int level, int sqlcode,
const char *msg, void *ctxt);
static void xml_errorHandler(void *ctxt, const char *msg, ...);
@@ -76,6 +79,7 @@ xml_in(PG_FUNCTION_ARGS)
char *s = PG_GETARG_CSTRING(0);
size_t len;
xmltype *vardata;
+ xmlDocPtr doc;
len = strlen(s);
vardata = palloc(len + VARHDRSZ);
@@ -86,7 +90,8 @@ xml_in(PG_FUNCTION_ARGS)
* Parse the data to check if it is well-formed XML data. Assume
* that ERROR occurred if parsing failed.
*/
- xml_parse(vardata, false, true);
+ doc = xml_parse(vardata, false, true);
+ xmlFreeDoc(doc);
PG_RETURN_XML_P(vardata);
#else
@@ -120,6 +125,7 @@ xml_recv(PG_FUNCTION_ARGS)
xmltype *result;
char *str;
int nbytes;
+ xmlDocPtr doc;
str = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
@@ -132,7 +138,8 @@ xml_recv(PG_FUNCTION_ARGS)
* Parse the data to check if it is well-formed XML data. Assume
* that ERROR occurred if parsing failed.
*/
- xml_parse(result, false, true);
+ doc = xml_parse(result, false, true);
+ xmlFreeDoc(doc);
PG_RETURN_XML_P(result);
#else
@@ -175,6 +182,21 @@ stringinfo_to_xmltype(StringInfo buf)
return result;
}
+
+
+static xmltype *
+xmlBuffer_to_xmltype(xmlBufferPtr buf)
+{
+ int32 len;
+ xmltype *result;
+
+ len = xmlBufferLength(buf) + VARHDRSZ;
+ result = palloc(len);
+ VARATT_SIZEP(result) = len;
+ memcpy(VARDATA(result), xmlBufferContent(buf), len - VARHDRSZ);
+
+ return result;
+}
#endif
@@ -221,7 +243,10 @@ xmltype *
xmlparse(text *data, bool is_document, bool preserve_whitespace)
{
#ifdef USE_LIBXML
- xml_parse(data, is_document, preserve_whitespace);
+ xmlDocPtr doc;
+
+ doc = xml_parse(data, is_document, preserve_whitespace);
+ xmlFreeDoc(doc);
return (xmltype *) data;
#else
@@ -280,31 +305,38 @@ xmltype *
xmlroot(xmltype *data, text *version, int standalone)
{
#ifdef USE_LIBXML
- xmltype *result;
- StringInfoData buf;
+ xmlDocPtr doc;
+ xmlBufferPtr buffer;
+ xmlSaveCtxtPtr save;
- initStringInfo(&buf);
+ doc = xml_parse((text *) data, true, true);
- /*
- * FIXME: This is probably supposed to be cleverer if there
- * already is an XML preamble.
- */
- appendStringInfo(&buf,"<?xml");
if (version)
+ doc->version = xmlStrdup(xml_text2xmlChar(version));
+ else
+ doc->version = NULL;
+
+ switch (standalone)
{
- appendStringInfo(&buf, " version=\"");
- appendStringInfoText(&buf, version);
- appendStringInfo(&buf, "\"");
+ case 1:
+ doc->standalone = 1;
+ break;
+ case -1:
+ doc->standalone = 0;
+ break;
+ default:
+ doc->standalone = -1;
+ break;
}
- if (standalone)
- appendStringInfo(&buf, " standalone=\"%s\"",
- (standalone == 1 ? "yes" : "no"));
- appendStringInfo(&buf, "?>");
- appendStringInfoText(&buf, (text *) data);
- result = stringinfo_to_xmltype(&buf);
- pfree(buf.data);
- return result;
+ buffer = xmlBufferCreate();
+ save = xmlSaveToBuffer(buffer, NULL, 0);
+ xmlSaveDoc(save, doc);
+ xmlSaveClose(save);
+
+ xmlFreeDoc(doc);
+
+ return xmlBuffer_to_xmltype(buffer);
#else
NO_XML_SUPPORT();
return NULL;
@@ -444,7 +476,14 @@ xml_init(void)
/* Now that xml_err_buf exists, safe to call xml_errorHandler */
xmlSetGenericErrorFunc(NULL, xml_errorHandler);
+#ifdef NOT_USED
+ /*
+ * FIXME: This doesn't work because libxml assumes that whatever
+ * libxml allocates, only libxml will free, so we can't just drop
+ * memory contexts behind it. This needs to be refined.
+ */
xmlMemSetup(xml_pfree, xml_palloc, xml_repalloc, xml_pstrdup);
+#endif
xmlInitParser();
LIBXML_TEST_VERSION;
}
@@ -528,8 +567,6 @@ xml_parse(text *data, bool is_document, bool preserve_whitespace)
* ) */
/* ... */
- if (doc)
- xmlFreeDoc(doc);
if (ctxt)
xmlFreeParserCtxt(ctxt);
xmlCleanupParser();
@@ -538,6 +575,7 @@ xml_parse(text *data, bool is_document, bool preserve_whitespace)
{
if (doc)
xmlFreeDoc(doc);
+ doc = NULL;
if (ctxt)
xmlFreeParserCtxt(ctxt);
xmlCleanupParser();
@@ -567,6 +605,7 @@ xml_text2xmlChar(text *in)
}
+#ifdef NOT_USED
/*
* Wrappers for memory management functions
*/
@@ -596,6 +635,7 @@ xml_pstrdup(const char *string)
{
return pstrdup(string);
}
+#endif /* NOT_USED */
/*
diff --git a/src/test/regress/expected/xml.out b/src/test/regress/expected/xml.out
index 14744656124..9ebef1404b9 100644
--- a/src/test/regress/expected/xml.out
+++ b/src/test/regress/expected/xml.out
@@ -124,6 +124,30 @@ SELECT xmlpi(name foo, 'bar');
SELECT xmlpi(name foo, 'in?>valid');
ERROR: invalid XML processing instruction
DETAIL: XML processing instruction cannot contain "?>".
+SELECT xmlroot(xml '<foo/>', version no value, standalone no value);
+ xmlroot
+-----------------------
+ <?xml version="1.0"?>
+ <foo/>
+
+(1 row)
+
+SELECT xmlroot(xml '<foo/>', version '2.0');
+ xmlroot
+-----------------------
+ <?xml version="2.0"?>
+ <foo/>
+
+(1 row)
+
+SELECT xmlroot(xmlroot(xml '<foo/>', version '1.0'), version '1.1', standalone no);
+ xmlroot
+---------------------------------------
+ <?xml version="1.1" standalone="no"?>
+ <foo/>
+
+(1 row)
+
SELECT xmlroot (
xmlelement (
name gazonk,
@@ -139,9 +163,11 @@ SELECT xmlroot (
version '1.0',
standalone yes
);
- xmlroot
-------------------------------------------------------------------------------------------
- <?xml version="1.0" standalone="yes"?><gazonk name="val" num="2"><qux>foo</qux></gazonk>
+ xmlroot
+----------------------------------------------------
+ <?xml version="1.0" standalone="yes"?>
+ <gazonk name="val" num="2"><qux>foo</qux></gazonk>
+
(1 row)
SELECT xmlserialize(content data as character varying) FROM xmltest;
diff --git a/src/test/regress/expected/xml_1.out b/src/test/regress/expected/xml_1.out
index 259bccbf4ba..662c0e236a8 100644
--- a/src/test/regress/expected/xml_1.out
+++ b/src/test/regress/expected/xml_1.out
@@ -62,6 +62,12 @@ SELECT xmlpi(name foo, 'bar');
ERROR: no XML support in this installation
SELECT xmlpi(name foo, 'in?>valid');
ERROR: no XML support in this installation
+SELECT xmlroot(xml '<foo/>', version no value, standalone no value);
+ERROR: no XML support in this installation
+SELECT xmlroot(xml '<foo/>', version '2.0');
+ERROR: no XML support in this installation
+SELECT xmlroot(xmlroot(xml '<foo/>', version '1.0'), version '1.1', standalone no);
+ERROR: no XML support in this installation
SELECT xmlroot (
xmlelement (
name gazonk,
diff --git a/src/test/regress/sql/xml.sql b/src/test/regress/sql/xml.sql
index 11db4905c76..cf96beab060 100644
--- a/src/test/regress/sql/xml.sql
+++ b/src/test/regress/sql/xml.sql
@@ -52,6 +52,9 @@ SELECT xmlpi(name xmlstuff);
SELECT xmlpi(name foo, 'bar');
SELECT xmlpi(name foo, 'in?>valid');
+SELECT xmlroot(xml '<foo/>', version no value, standalone no value);
+SELECT xmlroot(xml '<foo/>', version '2.0');
+SELECT xmlroot(xmlroot(xml '<foo/>', version '1.0'), version '1.1', standalone no);
SELECT xmlroot (
xmlelement (
--
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