From 546454f8a3ef2e749288cda972abfd1674aee340 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 12 May 2009 20:17:40 +0000
Subject: [PATCH] Fix intratransaction memory leaks in xml_recv, xmlconcat,
xmlroot, and xml_parse, all arising from the same sloppy usage of
parse_xml_decl. The original coding had that function returning its output
string parameters in the libxml context, which is long-lived, and all but one
of its callers neglected to free the strings afterwards. The easiest and
most bulletproof fix is to return the strings in the local palloc context
instead, since that's short-lived. This was only costing a dozen or two
bytes per function call, but that adds up fast if the function is called
repeatedly ...
Noted while poking at the more general problem of what to do with our
libxml memory allocation hooks. Back-patch to 8.3, which has the
identical coding.
---
src/backend/utils/adt/xml.c | 40 ++++++++++++++++++++++++++-----------
1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 5cb761773d9..7cfca13feaf 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.86 2009/04/08 21:51:38 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.87 2009/05/12 20:17:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -236,8 +236,6 @@ xml_out_internal(xmltype *x, pg_enc target_encoding)
}
appendStringInfoString(&buf, str + len);
- if (version)
- xmlFree(version);
pfree(str);
return buf.data;
@@ -455,7 +453,7 @@ xmlconcat(List *args)
if (!version)
global_version_no_value = true;
else if (!global_version)
- global_version = xmlStrdup(version);
+ global_version = version;
else if (xmlStrcmp(version, global_version) != 0)
global_version_no_value = true;
@@ -918,6 +916,24 @@ xml_init(void)
|| xmlIsCombiningQ(c) \
|| xmlIsExtender_ch(c))
+/* pnstrdup, but deal with xmlChar not char; len is measured in xmlChars */
+static xmlChar *
+xml_pnstrdup(const xmlChar *str, size_t len)
+{
+ xmlChar *result;
+
+ result = (xmlChar *) palloc((len + 1) * sizeof(xmlChar));
+ memcpy(result, str, len * sizeof(xmlChar));
+ result[len] = 0;
+ return result;
+}
+
+/*
+ * str is the null-terminated input string. Remaining arguments are
+ * output arguments; each can be NULL if value is not wanted.
+ * version and encoding are returned as locally-palloc'd strings.
+ * Result is 0 if OK, an error code if not.
+ */
static int
parse_xml_decl(const xmlChar * str, size_t *lenp,
xmlChar ** version, xmlChar ** encoding, int *standalone)
@@ -930,6 +946,7 @@ parse_xml_decl(const xmlChar * str, size_t *lenp,
xml_init();
+ /* Initialize output arguments to "not present" */
if (version)
*version = NULL;
if (encoding)
@@ -971,7 +988,7 @@ parse_xml_decl(const xmlChar * str, size_t *lenp,
return XML_ERR_VERSION_MISSING;
if (version)
- *version = xmlStrndup(p + 1, q - p - 1);
+ *version = xml_pnstrdup(p + 1, q - p - 1);
p = q + 1;
}
else
@@ -999,7 +1016,7 @@ parse_xml_decl(const xmlChar * str, size_t *lenp,
return XML_ERR_MISSING_ENCODING;
if (encoding)
- *encoding = xmlStrndup(p + 1, q - p - 1);
+ *encoding = xml_pnstrdup(p + 1, q - p - 1);
p = q + 1;
}
else
@@ -1172,8 +1189,6 @@ xml_parse(text *data, XmlOptionType xmloption_arg, bool preserve_whitespace,
xmlChar *version = NULL;
int standalone = -1;
- doc = xmlNewDoc(NULL);
-
res_code = parse_xml_decl(utf8string,
&count, &version, NULL, &standalone);
if (res_code != 0)
@@ -1181,15 +1196,16 @@ xml_parse(text *data, XmlOptionType xmloption_arg, bool preserve_whitespace,
"invalid XML content: invalid XML declaration",
res_code);
+ doc = xmlNewDoc(version);
+ Assert(doc->encoding == NULL);
+ doc->encoding = xmlStrdup((const xmlChar *) "UTF-8");
+ doc->standalone = standalone;
+
res_code = xmlParseBalancedChunkMemory(doc, NULL, NULL, 0,
utf8string + count, NULL);
if (res_code != 0)
xml_ereport(ERROR, ERRCODE_INVALID_XML_CONTENT,
"invalid XML content");
-
- doc->version = xmlStrdup(version);
- doc->encoding = xmlStrdup((xmlChar *) "UTF-8");
- doc->standalone = standalone;
}
xmlFreeParserCtxt(ctxt);
--
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