On 05.06.25 11:47, Jim Jones wrote:
> Taking a further look at xml.c I am wondering if other functions might
> also need some attention in this regard:
>
> * xmlTextWriterStartElement [3]
> * xmlTextWriterWriteAttribute [4]
> * xmlTextWriterWriteRaw [5]
> * xmlTextWriterEndAttribute [6]
>
> We're assuming they never fail. Perhaps something like this?
> ...
> nbytes = xmlTextWriterStartElement(writer, (xmlChar *) xexpr->name);
> if (nbytes == -1 || xmlerrcxt->err_occurred)
> xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
> "could not allocate xmlTextWriterStartElement");
>
There is also a further xmlXPathCastNodeToString() call in xml.c at
xml_xmlnodetoxmltype() - it calls xmlNodeGetContent() and it can return
NULL.
xmlChar *str;
str = xmlXPathCastNodeToString(cur);
PG_TRY();
{
/* Here we rely on XML having the same representation as TEXT */
char *escaped = escape_xml((char *) str);
result = (xmltype *) cstring_to_text(escaped);
pfree(escaped);
}
PG_FINALLY();
{
xmlFree(str);
}
PG_END_TRY();
The function pgxmlNodeSetToText() also calls xmlXPathCastNodeToString(),
but apparently xmlBufferAdd() can handle NULL values.[1]
Best regards, Jim
1 -
https://github.com/GNOME/libxml2/blob/2b6b3945f2df548b56f2c73c490dda9781f92eb2/buf.c#L989
