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Fix memory leaks in for_xml_ffunc() by adding missing regfree() calls #4663

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Merged
tanscorpio7 merged 2 commits into from
Mar 19, 2026
+33 −23
Merged

Fix memory leaks in for_xml_ffunc() by adding missing regfree() calls #4663

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028ac6f
Fix memory leaks in for_xml_ffunc() by adding missing regfree() calls…
rohit01010 Mar 18, 2026
7cf319d
Merge branch 'BABEL_6_X_DEV' into fix_memory_leaks-6x
rohit01010 Mar 19, 2026
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56 changes: 33 additions & 23 deletions contrib/babelfishpg_tsql/src/tsql_for/forxml.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,7 @@
#include "utils/typcache.h"
#include "catalog/pg_type.h"
#include "catalog/namespace.h"

#include <regex.h>
#include "catalog/pg_collation.h"

#include "tsql_for.h"

Expand Down Expand Up @@ -150,37 +149,48 @@ static StringInfo
for_xml_ffunc(PG_FUNCTION_ARGS)
{
StringInfo res = makeStringInfo();
char *state = ((StringInfo) PG_GETARG_POINTER(0))->data;
char *state;

if (PG_ARGISNULL(0))
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected null state in FOR XML processing")));

state = ((StringInfo) PG_GETARG_POINTER(0))->data;

if (state[0] == '{') /* '{' indicates that root was specified, so
* add the corresponding end tag */
{
/* set up regex to match first tag */
char *pattern = "<([^\\/>]+)[\\/]*>";
regex_t preg;
regmatch_t match,
pmatch[1];
StringInfoData root;

if (regcomp(&preg, pattern, REG_EXTENDED) != 0)
/*
* Using PostgreSQL's textregexsubstr() to extract the root tag name.
* simpler than manual regex handling and leverages PostgreSQL's
* cached regex compilation and proper memory management.
*/
text *state_text = cstring_to_text(state);
text *pattern_text = cstring_to_text("<([^\\/>]+)[\\/]*>");
Datum root_tag_datum;
text *root_tag_text;
char *root_tag;

/* Extract the root tag name using textregexsubstr */
root_tag_datum = DirectFunctionCall2Coll(textregexsubstr,
C_COLLATION_OID,
PointerGetDatum(state_text),
PointerGetDatum(pattern_text));

if (DatumGetPointer(root_tag_datum) == NULL)
{
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected error parsing xml root tag")));
}

if (regexec(&preg, state, 1, pmatch, 0) != 0)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("unexpected error parsing xml root tag")));
root_tag_text = DatumGetTextPP(root_tag_datum);
root_tag = text_to_cstring(root_tag_text);

match = pmatch[0];
/* we will be bashing the string in state, so copy it into res first */
/* Copy state content (skip the '{' marker) and add closing tag */
appendStringInfoString(res, state + 1);

/* copy the root tag */
state[match.rm_eo - 1] = '\0';
initStringInfo(&root);
appendStringInfoString(&root, state + match.rm_so + 1);
appendStringInfo(res, "</%s>", root.data);
appendStringInfo(res, "</%s>", root_tag);
}
else
{
Expand Down
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