From c4810d9ae05a4c6b93cfbe5e58ae55cd1a0d3808 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 3 Mar 2010 19:10:40 +0000 Subject: [PATCH] Make contrib/xml2 use core xml.c's error handler, when available (that is, in versions >= 8.3). The core code is more robust and efficient than what was there before, and this also reduces risks involved in swapping different libxml error handler settings. Before 8.3, there is still some risk of problems if add-on modules such as Perl invoke libxml without setting their own error handler. Given the lack of reports I'm not sure there's a risk in practice, so I didn't take the step of actually duplicating the core code into older contrib/xml2 branches. Instead I just tweaked the existing code to ensure it didn't leave a dangling pointer to short-lived memory when throwing an error. --- contrib/xml2/xpath.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/contrib/xml2/xpath.c b/contrib/xml2/xpath.c index 9c091c9572c..59f7c618645 100644 --- a/contrib/xml2/xpath.c +++ b/contrib/xml2/xpath.c @@ -103,9 +103,20 @@ elog_error(const char *explain, bool force) (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION), errmsg("%s", explain))); else + { + /* + * Ensure pgxml_errorMsg is reset to null before we give up + * control. This provides some protection against crashes if + * pgxml_errorHandler is invoked again later, perhaps as a + * result of other modules' use of libxml. + */ + char *msg = pgxml_errorMsg; + + pgxml_errorMsg = NULL; ereport(ERROR, (errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION), - errmsg("%s: %s", explain, pgxml_errorMsg))); + errmsg("%s: %s", explain, msg))); + } } }