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postgres/contrib/xml2/xpath.c

888 lines
21 KiB

/*
* contrib/xml2/xpath.c
*
* Parser interface for DOM-based parser (libxml) rather than
* stream-based SAX-type parser
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "executor/spi.h"
#include "fmgr.h"
#include "funcapi.h"
#include "lib/stringinfo.h"
#include "utils/builtins.h"
#include "utils/xml.h"
/* libxml includes */
#include <libxml/xpath.h>
#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
#include <libxml/xmlerror.h>
#include <libxml/parserInternals.h>
PG_MODULE_MAGIC_EXT(
.name = "xml2",
.version = PG_VERSION
);
/* exported for use by xslt_proc.c */
PgXmlErrorContext *pgxml_parser_init(PgXmlStrictness strictness);
/* workspace for pgxml_xpath() */
typedef struct
{
xmlDocPtr doctree;
xmlXPathContextPtr ctxt;
xmlXPathObjectPtr res;
} xpath_workspace;
/* local declarations */
static xmlChar *pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
xmlChar *toptagname, xmlChar *septagname,
xmlChar *plainsep);
static text *pgxml_result_to_text(xmlXPathObjectPtr res, xmlChar *toptag,
xmlChar *septag, xmlChar *plainsep);
static xmlChar *pgxml_texttoxmlchar(text *textstring);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
static xpath_workspace *pgxml_xpath(text *document, xmlChar *xpath,
PgXmlErrorContext *xmlerrcxt);
static void cleanup_workspace(xpath_workspace *workspace);
/*
* Initialize for xml parsing.
*
* As with the underlying pg_xml_init function, calls to this MUST be followed
* by a PG_TRY block that guarantees that pg_xml_done is called.
*/
PgXmlErrorContext *
pgxml_parser_init(PgXmlStrictness strictness)
{
PgXmlErrorContext *xmlerrcxt;
/* Set up error handling (we share the core's error handler) */
xmlerrcxt = pg_xml_init(strictness);
/* Note: we're assuming an elog cannot be thrown by the following calls */
/* Initialize libxml */
xmlInitParser();
return xmlerrcxt;
}
/* Encodes special characters (<, >, &, " and \r) as XML entities */
PG_FUNCTION_INFO_V1(xml_encode_special_chars);
Datum
xml_encode_special_chars(PG_FUNCTION_ARGS)
{
text *tin = PG_GETARG_TEXT_PP(0);
text *volatile tout = NULL;
xmlChar *volatile tt = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
PG_TRY();
{
xmlChar *ts;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
ts = pgxml_texttoxmlchar(tin);
tt = xmlEncodeSpecialChars(NULL, ts);
if (tt == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate xmlChar");
pfree(ts);
tout = cstring_to_text((char *) tt);
}
PG_CATCH();
{
if (tt != NULL)
xmlFree(tt);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (tt != NULL)
xmlFree(tt);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, false);
PG_RETURN_TEXT_P(tout);
}
/*
* Function translates a nodeset into a text representation
*
* iterates over each node in the set and calls xmlNodeDump to write it to
* an xmlBuffer -from which an xmlChar * string is returned.
*
* each representation is surrounded by <tagname> ... </tagname>
*
* plainsep is an ordinary (not tag) separator - if used, then nodes are
* cast to string as output method
*/
static xmlChar *
pgxmlNodeSetToText(xmlNodeSetPtr nodeset,
xmlChar *toptagname,
xmlChar *septagname,
xmlChar *plainsep)
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
volatile xmlBufferPtr buf = NULL;
xmlChar *volatile result = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
/* spin up some error handling */
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
buf = xmlBufferCreate();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (buf == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate xmlBuffer");
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
{
xmlBufferWriteChar(buf, "<");
xmlBufferWriteCHAR(buf, toptagname);
xmlBufferWriteChar(buf, ">");
}
if (nodeset != NULL)
{
for (int i = 0; i < nodeset->nodeNr; i++)
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (plainsep != NULL)
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlBufferWriteCHAR(buf,
xmlXPathCastNodeToString(nodeset->nodeTab[i]));
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
/* If this isn't the last entry, write the plain sep. */
if (i < (nodeset->nodeNr) - 1)
xmlBufferWriteChar(buf, (char *) plainsep);
}
else
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
{
xmlBufferWriteChar(buf, "<");
xmlBufferWriteCHAR(buf, septagname);
xmlBufferWriteChar(buf, ">");
}
xmlNodeDump(buf,
nodeset->nodeTab[i]->doc,
nodeset->nodeTab[i],
1, 0);
if ((septagname != NULL) && (xmlStrlen(septagname) > 0))
{
xmlBufferWriteChar(buf, "</");
xmlBufferWriteCHAR(buf, septagname);
xmlBufferWriteChar(buf, ">");
}
}
}
}
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if ((toptagname != NULL) && (xmlStrlen(toptagname) > 0))
{
xmlBufferWriteChar(buf, "</");
xmlBufferWriteCHAR(buf, toptagname);
xmlBufferWriteChar(buf, ">");
}
result = xmlStrdup(xmlBufferContent(buf));
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (result == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
}
PG_CATCH();
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (buf)
xmlBufferFree(buf);
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_END_TRY();
xmlBufferFree(buf);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, false);
return result;
}
/* Translate a PostgreSQL "varlena" -i.e. a variable length parameter
* into the libxml2 representation
*/
static xmlChar *
pgxml_texttoxmlchar(text *textstring)
{
return (xmlChar *) text_to_cstring(textstring);
}
/* Publicly visible XPath functions */
/*
* This is a "raw" xpath function. Check that it returns child elements
* properly
*/
PG_FUNCTION_INFO_V1(xpath_nodeset);
Datum
xpath_nodeset(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_PP(0);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
8 years ago
text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
xmlChar *toptag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
xmlChar *septag = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(3));
xmlChar *xpath;
text *volatile xpres = NULL;
xpath_workspace *volatile workspace = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
xpath = pgxml_texttoxmlchar(xpathsupp);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
workspace = pgxml_xpath(document, xpath, xmlerrcxt);
xpres = pgxml_result_to_text(workspace->res, toptag, septag, NULL);
}
PG_CATCH();
{
if (workspace)
cleanup_workspace(workspace);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
/*
* The following function is almost identical, but returns the elements in
* a list.
*/
PG_FUNCTION_INFO_V1(xpath_list);
Datum
xpath_list(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_PP(0);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
8 years ago
text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
xmlChar *plainsep = pgxml_texttoxmlchar(PG_GETARG_TEXT_PP(2));
xmlChar *xpath;
text *volatile xpres = NULL;
xpath_workspace *volatile workspace = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
xpath = pgxml_texttoxmlchar(xpathsupp);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
workspace = pgxml_xpath(document, xpath, xmlerrcxt);
xpres = pgxml_result_to_text(workspace->res, NULL, NULL, plainsep);
}
PG_CATCH();
{
if (workspace)
cleanup_workspace(workspace);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
PG_FUNCTION_INFO_V1(xpath_string);
Datum
xpath_string(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_PP(0);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
8 years ago
text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
xmlChar *xpath;
int32 pathsize;
text *volatile xpres = NULL;
xpath_workspace *volatile workspace = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
pathsize = VARSIZE_ANY_EXHDR(xpathsupp);
/*
* We encapsulate the supplied path with "string()" = 8 chars + 1 for NUL
* at end
*/
/* We could try casting to string using the libxml function? */
xpath = (xmlChar *) palloc(pathsize + 9);
memcpy(xpath, "string(", 7);
memcpy(xpath + 7, VARDATA_ANY(xpathsupp), pathsize);
xpath[pathsize + 7] = ')';
xpath[pathsize + 8] = '\0';
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
workspace = pgxml_xpath(document, xpath, xmlerrcxt);
xpres = pgxml_result_to_text(workspace->res, NULL, NULL, NULL);
}
PG_CATCH();
{
if (workspace)
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
pfree(xpath);
if (xpres == NULL)
PG_RETURN_NULL();
PG_RETURN_TEXT_P(xpres);
}
PG_FUNCTION_INFO_V1(xpath_number);
Datum
xpath_number(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_PP(0);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
8 years ago
text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
xmlChar *xpath;
volatile float4 fRes = 0.0;
volatile bool isNull = false;
xpath_workspace *volatile workspace = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
xpath = pgxml_texttoxmlchar(xpathsupp);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
workspace = pgxml_xpath(document, xpath, xmlerrcxt);
pfree(xpath);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (workspace->res == NULL)
isNull = true;
else
fRes = xmlXPathCastToNumber(workspace->res);
}
PG_CATCH();
{
if (workspace)
cleanup_workspace(workspace);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (isNull || xmlXPathIsNaN(fRes))
PG_RETURN_NULL();
PG_RETURN_FLOAT4(fRes);
}
PG_FUNCTION_INFO_V1(xpath_bool);
Datum
xpath_bool(PG_FUNCTION_ARGS)
{
text *document = PG_GETARG_TEXT_PP(0);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
8 years ago
text *xpathsupp = PG_GETARG_TEXT_PP(1); /* XPath expression */
xmlChar *xpath;
volatile int bRes = 0;
xpath_workspace *volatile workspace = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
xpath = pgxml_texttoxmlchar(xpathsupp);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
workspace = pgxml_xpath(document, xpath, xmlerrcxt);
pfree(xpath);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (workspace->res == NULL)
bRes = 0;
else
bRes = xmlXPathCastToBoolean(workspace->res);
}
PG_CATCH();
{
if (workspace)
cleanup_workspace(workspace);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
cleanup_workspace(workspace);
pg_xml_done(xmlerrcxt, false);
PG_RETURN_BOOL(bRes);
}
/* Core function to evaluate XPath query */
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
static xpath_workspace *
pgxml_xpath(text *document, xmlChar *xpath, PgXmlErrorContext *xmlerrcxt)
{
int32 docsize = VARSIZE_ANY_EXHDR(document);
xmlXPathCompExprPtr comppath;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xpath_workspace *workspace = (xpath_workspace *)
palloc0(sizeof(xpath_workspace));
workspace->doctree = NULL;
workspace->ctxt = NULL;
workspace->res = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
workspace->doctree = xmlReadMemory((char *) VARDATA_ANY(document),
docsize, NULL, NULL,
XML_PARSE_NOENT);
if (workspace->doctree != NULL)
{
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
workspace->ctxt = xmlXPathNewContext(workspace->doctree);
workspace->ctxt->node = xmlDocGetRootElement(workspace->doctree);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
/* compile the path */
comppath = xmlXPathCtxtCompile(workspace->ctxt, xpath);
if (comppath == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
"XPath Syntax Error");
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
/* Now evaluate the path expression. */
workspace->res = xmlXPathCompiledEval(comppath, workspace->ctxt);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
xmlXPathFreeCompExpr(comppath);
}
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
return workspace;
}
/* Clean up after processing the result of pgxml_xpath() */
static void
cleanup_workspace(xpath_workspace *workspace)
{
if (workspace->res)
xmlXPathFreeObject(workspace->res);
workspace->res = NULL;
if (workspace->ctxt)
xmlXPathFreeContext(workspace->ctxt);
workspace->ctxt = NULL;
if (workspace->doctree)
xmlFreeDoc(workspace->doctree);
workspace->doctree = NULL;
}
static text *
pgxml_result_to_text(xmlXPathObjectPtr res,
xmlChar *toptag,
xmlChar *septag,
xmlChar *plainsep)
{
xmlChar *volatile xpresstr = NULL;
text *volatile xpres = NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PgXmlErrorContext *xmlerrcxt;
if (res == NULL)
return NULL;
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
/* spin some error handling */
xmlerrcxt = pg_xml_init(PG_XML_STRICTNESS_ALL);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_TRY();
{
switch (res->type)
{
case XPATH_NODESET:
xpresstr = pgxmlNodeSetToText(res->nodesetval,
toptag,
septag, plainsep);
break;
case XPATH_STRING:
xpresstr = xmlStrdup(res->stringval);
if (xpresstr == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
break;
default:
elog(NOTICE, "unsupported XQuery result: %d", res->type);
xpresstr = xmlStrdup((const xmlChar *) "<unsupported/>");
if (xpresstr == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
}
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
/* Now convert this result back to text */
xpres = cstring_to_text((char *) xpresstr);
}
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
PG_CATCH();
{
if (xpresstr != NULL)
xmlFree(xpresstr);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
/* Free various storage */
xmlFree(xpresstr);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
pg_xml_done(xmlerrcxt, false);
return xpres;
}
/*
* xpath_table is a table function. It needs some tidying (as do the
* other functions here!
*/
PG_FUNCTION_INFO_V1(xpath_table);
Datum
xpath_table(PG_FUNCTION_ARGS)
{
/* Function parameters */
char *pkeyfield = text_to_cstring(PG_GETARG_TEXT_PP(0));
char *xmlfield = text_to_cstring(PG_GETARG_TEXT_PP(1));
char *relname = text_to_cstring(PG_GETARG_TEXT_PP(2));
char *xpathset = text_to_cstring(PG_GETARG_TEXT_PP(3));
char *condition = text_to_cstring(PG_GETARG_TEXT_PP(4));
/* SPI (input tuple) support */
SPITupleTable *tuptable;
HeapTuple spi_tuple;
TupleDesc spi_tupdesc;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
AttInMetadata *attinmeta;
char **values;
xmlChar **xpaths;
char *pos;
const char *pathsep = "|";
int numpaths;
int ret;
uint64 proc;
int j;
int rownr; /* For issuing multiple rows from one original
* document */
bool had_values; /* To determine end of nodeset results */
StringInfoData query_buf;
PgXmlErrorContext *xmlerrcxt;
volatile xmlDocPtr doctree = NULL;
InitMaterializedSRF(fcinfo, MAT_SRF_USE_EXPECTED_DESC);
/* must have at least one output column (for the pkey) */
if (rsinfo->setDesc->natts < 1)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("xpath_table must have at least one output column")));
/*
* At the moment we assume that the returned attributes make sense for the
* XPath specified (i.e. we trust the caller). It's not fatal if they get
* it wrong - the input function for the column type will raise an error
* if the path result can't be converted into the correct binary
* representation.
*/
attinmeta = TupleDescGetAttInMetadata(rsinfo->setDesc);
values = (char **) palloc(rsinfo->setDesc->natts * sizeof(char *));
xpaths = (xmlChar **) palloc(rsinfo->setDesc->natts * sizeof(xmlChar *));
/*
* Split XPaths. xpathset is a writable CString.
*
* Note that we stop splitting once we've done all needed for tupdesc
*/
numpaths = 0;
pos = xpathset;
while (numpaths < (rsinfo->setDesc->natts - 1))
{
xpaths[numpaths++] = (xmlChar *) pos;
pos = strstr(pos, pathsep);
if (pos != NULL)
{
*pos = '\0';
pos++;
}
else
break;
}
/* Now build query */
initStringInfo(&query_buf);
/* Build initial sql statement */
appendStringInfo(&query_buf, "SELECT %s, %s FROM %s WHERE %s",
pkeyfield,
xmlfield,
relname,
condition);
SPI_connect();
if ((ret = SPI_exec(query_buf.data, 0)) != SPI_OK_SELECT)
elog(ERROR, "xpath_table: SPI execution failed for query %s",
query_buf.data);
proc = SPI_processed;
tuptable = SPI_tuptable;
spi_tupdesc = tuptable->tupdesc;
/*
* Check that SPI returned correct result. If you put a comma into one of
* the function parameters, this will catch it when the SPI query returns
* e.g. 3 columns.
*/
if (spi_tupdesc->natts != 2)
{
ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("expression returning multiple columns is not valid in parameter list"),
errdetail("Expected two columns in SPI result, got %d.", spi_tupdesc->natts)));
}
/*
* Setup the parser. This should happen after we are done evaluating the
* query, in case it calls functions that set up libxml differently.
*/
xmlerrcxt = pgxml_parser_init(PG_XML_STRICTNESS_LEGACY);
PG_TRY();
{
/* For each row i.e. document returned from SPI */
uint64 i;
for (i = 0; i < proc; i++)
{
char *pkey;
char *xmldoc;
xmlXPathContextPtr ctxt;
xmlXPathObjectPtr res;
xmlChar *resstr;
xmlXPathCompExprPtr comppath;
HeapTuple ret_tuple;
/* Extract the row data as C Strings */
spi_tuple = tuptable->vals[i];
pkey = SPI_getvalue(spi_tuple, spi_tupdesc, 1);
xmldoc = SPI_getvalue(spi_tuple, spi_tupdesc, 2);
/*
* Clear the values array, so that not-well-formed documents
* return NULL in all columns. Note that this also means that
* spare columns will be NULL.
*/
for (j = 0; j < rsinfo->setDesc->natts; j++)
values[j] = NULL;
/* Insert primary key */
values[0] = pkey;
/* Parse the document */
if (xmldoc)
doctree = xmlReadMemory(xmldoc, strlen(xmldoc),
NULL, NULL,
XML_PARSE_NOENT);
8 years ago
else /* treat NULL as not well-formed */
doctree = NULL;
if (doctree == NULL)
{
/* not well-formed, so output all-NULL tuple */
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
tuplestore_puttuple(rsinfo->setResult, ret_tuple);
heap_freetuple(ret_tuple);
}
else
{
/* New loop here - we have to deal with nodeset results */
rownr = 0;
do
{
/* Now evaluate the set of xpaths. */
had_values = false;
for (j = 0; j < numpaths; j++)
{
ctxt = xmlXPathNewContext(doctree);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (ctxt == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt,
ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate XPath context");
ctxt->node = xmlDocGetRootElement(doctree);
/* compile the path */
1 year ago
comppath = xmlXPathCtxtCompile(ctxt, xpaths[j]);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (comppath == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt, ERROR,
ERRCODE_INVALID_ARGUMENT_FOR_XQUERY,
"XPath Syntax Error");
/* Now evaluate the path expression. */
res = xmlXPathCompiledEval(comppath, ctxt);
xmlXPathFreeCompExpr(comppath);
if (res != NULL)
{
switch (res->type)
{
case XPATH_NODESET:
/* We see if this nodeset has enough nodes */
if (res->nodesetval != NULL &&
rownr < res->nodesetval->nodeNr)
{
resstr = xmlXPathCastNodeToString(res->nodesetval->nodeTab[rownr]);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt,
ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
had_values = true;
}
else
resstr = NULL;
break;
case XPATH_STRING:
resstr = xmlStrdup(res->stringval);
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt,
ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
break;
default:
elog(NOTICE, "unsupported XQuery result: %d", res->type);
resstr = xmlStrdup((const xmlChar *) "<unsupported/>");
xml2: Improve error handling of libxml2 calls The contrib module xml2/ has always been fuzzy with the cleanup of the memory allocated by the calls internal to libxml2, even if there are APIs in place giving a lot of control over the error behavior, all located in the backend's xml.c. The code paths fixed in the commit address multiple defects, while sanitizing the code: - In xpath.c, several allocations are done by libxml2 for xpath_workspace, whose memory cleanup could go out of sight as it relied on a single TRY/CATCH block done in pgxml_xpath(). workspace->res is allocated by libxml2, and may finish by not being freed at all upon a failure outside of a TRY area. This code is refactored so as the TRY/CATCH block of pgxml_xpath() is moved one level higher to its callers, which are responsible for cleaning up the contents of a workspace on failure. cleanup_workspace() now requires a volatile workspace, forcing as a rule that a TRY/CATCH block should be used. - Several calls, like xmlStrdup(), xmlXPathNewContext(), xmlXPathCtxtCompile(), etc. can return NULL on failures (for most of them allocation failures. These forgot to check for failures, or missed that pg_xml_error_occurred() should be called, to check if an error is already on the stack. - Some memory allocated by libxml2 calls was freed in an incorrect way, "resstr" in xslt_process() being one example. The class of errors fixed here are for problems that are unlikely going to happen in practice, so no backpatch is done. The changes have finished by being rather invasive, so it is perhaps not a bad thing to be conservative and to keep these changes only on HEAD anyway. Author: Michael Paquier <michael@paquier.xyz> Reported-by: Karavaev Alexey <maralist86@mail.ru> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18943-2f2a04ab03904598@postgresql.org
3 months ago
if (resstr == NULL || pg_xml_error_occurred(xmlerrcxt))
xml_ereport(xmlerrcxt,
ERROR, ERRCODE_OUT_OF_MEMORY,
"could not allocate result");
}
/*
* Insert this into the appropriate column in the
* result tuple.
*/
values[j + 1] = (char *) resstr;
}
xmlXPathFreeContext(ctxt);
}
/* Now add the tuple to the output, if there is one. */
if (had_values)
{
ret_tuple = BuildTupleFromCStrings(attinmeta, values);
tuplestore_puttuple(rsinfo->setResult, ret_tuple);
heap_freetuple(ret_tuple);
}
rownr++;
} while (had_values);
}
if (doctree != NULL)
xmlFreeDoc(doctree);
doctree = NULL;
if (pkey)
pfree(pkey);
if (xmldoc)
pfree(xmldoc);
}
}
PG_CATCH();
{
if (doctree != NULL)
xmlFreeDoc(doctree);
pg_xml_done(xmlerrcxt, true);
PG_RE_THROW();
}
PG_END_TRY();
if (doctree != NULL)
xmlFreeDoc(doctree);
pg_xml_done(xmlerrcxt, false);
SPI_finish();
/*
* SFRM_Materialize mode expects us to return a NULL Datum. The actual
* tuples are in our tuplestore and passed back through rsinfo->setResult.
* rsinfo->setDesc is set to the tuple description that we actually used
* to build our tuples with, so the caller can verify we did what it was
* expecting.
*/
return (Datum) 0;
}