postgresql/contrib/ltree/ltxtquery_op.c
Noah Misch 5976097c0f Prevent stack overflow in query-type functions.
The tsquery, ltxtquery and query_int data types have a common ancestor.
Having acquired check_stack_depth() calls independently, each was
missing at least one call.  Back-patch to 9.0 (all supported versions).
2015-10-05 10:06:30 -04:00

116 lines
2.5 KiB
C

/*
* txtquery operations with ltree
* Teodor Sigaev <teodor@stack.net>
* contrib/ltree/ltxtquery_op.c
*/
#include "postgres.h"
#include <ctype.h>
#include "ltree.h"
#include "miscadmin.h"
PG_FUNCTION_INFO_V1(ltxtq_exec);
PG_FUNCTION_INFO_V1(ltxtq_rexec);
/*
* check for boolean condition
*/
bool
ltree_execute(ITEM *curitem, void *checkval, bool calcnot, bool (*chkcond) (void *checkval, ITEM *val))
{
/* since this function recurses, it could be driven to stack overflow */
check_stack_depth();
if (curitem->type == VAL)
return (*chkcond) (checkval, curitem);
else if (curitem->val == (int32) '!')
{
return (calcnot) ?
((ltree_execute(curitem + 1, checkval, calcnot, chkcond)) ? false : true)
: true;
}
else if (curitem->val == (int32) '&')
{
if (ltree_execute(curitem + curitem->left, checkval, calcnot, chkcond))
return ltree_execute(curitem + 1, checkval, calcnot, chkcond);
else
return false;
}
else
{ /* |-operator */
if (ltree_execute(curitem + curitem->left, checkval, calcnot, chkcond))
return true;
else
return ltree_execute(curitem + 1, checkval, calcnot, chkcond);
}
}
typedef struct
{
ltree *node;
char *operand;
} CHKVAL;
static bool
checkcondition_str(void *checkval, ITEM *val)
{
ltree_level *level = LTREE_FIRST(((CHKVAL *) checkval)->node);
int tlen = ((CHKVAL *) checkval)->node->numlevel;
char *op = ((CHKVAL *) checkval)->operand + val->distance;
int (*cmpptr) (const char *, const char *, size_t);
cmpptr = (val->flag & LVAR_INCASE) ? ltree_strncasecmp : strncmp;
while (tlen > 0)
{
if (val->flag & LVAR_SUBLEXEME)
{
if (compare_subnode(level, op, val->length, cmpptr, (val->flag & LVAR_ANYEND)))
return true;
}
else if (
(
val->length == level->len ||
(level->len > val->length && (val->flag & LVAR_ANYEND))
) &&
(*cmpptr) (op, level->name, val->length) == 0)
return true;
tlen--;
level = LEVEL_NEXT(level);
}
return false;
}
Datum
ltxtq_exec(PG_FUNCTION_ARGS)
{
ltree *val = PG_GETARG_LTREE(0);
ltxtquery *query = PG_GETARG_LTXTQUERY(1);
CHKVAL chkval;
bool result;
chkval.node = val;
chkval.operand = GETOPERAND(query);
result = ltree_execute(
GETQUERY(query),
&chkval,
true,
checkcondition_str
);
PG_FREE_IF_COPY(val, 0);
PG_FREE_IF_COPY(query, 1);
PG_RETURN_BOOL(result);
}
Datum
ltxtq_rexec(PG_FUNCTION_ARGS)
{
PG_RETURN_DATUM(DirectFunctionCall2(ltxtq_exec,
PG_GETARG_DATUM(1),
PG_GETARG_DATUM(0)
));
}