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Fix multibyte issue in ltree_strncasecmp().

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Previously, the API for ltree_strncasecmp() took two inputs but only
one length (that of the smaller input). It truncated the larger input
to that length, but that could break a multibyte sequence.

Change the API to be a check for prefix equality (possibly
case-insensitive) instead, which is all that's needed by the
callers. Also, provide the lengths of both inputs.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/5f65b85740197ba6249ea507cddf609f84a6188b.camel%40j-davis.com
Backpatch-through: 14
This commit is contained in:
Jeff Davis
2025-12-16 10:35:40 -08:00
parent 1d0fc2499f
commit b8cfe9dc2e
3 changed files with 37 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
contrib/ltree/lquery_op.c
View File

@@ -41,7 +41,8 @@ getlexeme(char *start, char *end, int *len)
}
bool
compare_subnode(ltree_level *t, char *qn, int len, int (*cmpptr) (const char *, const char *, size_t), bool anyend)
compare_subnode(ltree_level *t, char *qn, int len,
ltree_prefix_eq_func prefix_eq, bool anyend)
{
char *endt = t->name + t->len;
char *endq = qn + len;
@@ -57,7 +58,7 @@ compare_subnode(ltree_level *t, char *qn, int len, int (*cmpptr) (const char *,
while ((tn = getlexeme(tn, endt, &lent)) != NULL)
{
if ((lent == lenq || (lent > lenq && anyend)) &&
(*cmpptr) (qn, tn, lenq) == 0)
(*prefix_eq) (qn, lenq, tn, lent))
{
isok = true;
@@ -74,14 +75,29 @@ compare_subnode(ltree_level *t, char *qn, int len, int (*cmpptr) (const char *,
return true;
}
int
ltree_strncasecmp(const char *a, const char *b, size_t s)
/*
* Check if 'a' is a prefix of 'b'.
*/
bool
ltree_prefix_eq(const char *a, size_t a_sz, const char *b, size_t b_sz)
{
char *al = str_tolower(a, s, DEFAULT_COLLATION_OID);
char *bl = str_tolower(b, s, DEFAULT_COLLATION_OID);
int res;
if (a_sz > b_sz)
return false;
else
return (strncmp(a, b, a_sz) == 0);
}
res = strncmp(al, bl, s);
/*
* Case-insensitive check if 'a' is a prefix of 'b'.
*/
bool
ltree_prefix_eq_ci(const char *a, size_t a_sz, const char *b, size_t b_sz)
{
char *al = str_tolower(a, a_sz, DEFAULT_COLLATION_OID);
char *bl = str_tolower(b, b_sz, DEFAULT_COLLATION_OID);
bool res;
res = (strncmp(al, bl, a_sz) == 0);
pfree(al);
pfree(bl);
@@ -109,19 +125,19 @@ checkLevel(lquery_level *curq, ltree_level *curt)
for (int i = 0; i < curq->numvar; i++)
{
int (*cmpptr) (const char *, const char *, size_t);
ltree_prefix_eq_func prefix_eq;
cmpptr = (curvar->flag & LVAR_INCASE) ? ltree_strncasecmp : strncmp;
prefix_eq = (curvar->flag & LVAR_INCASE) ? ltree_prefix_eq_ci : ltree_prefix_eq;
if (curvar->flag & LVAR_SUBLEXEME)
{
if (compare_subnode(curt, curvar->name, curvar->len, cmpptr,
if (compare_subnode(curt, curvar->name, curvar->len, prefix_eq,
(curvar->flag & LVAR_ANYEND)))
return success;
}
else if ((curvar->len == curt->len ||
(curt->len > curvar->len && (curvar->flag & LVAR_ANYEND))) &&
(*cmpptr) (curvar->name, curt->name, curvar->len) == 0)
(*prefix_eq) (curvar->name, curvar->len, curt->name, curt->len))
return success;
curvar = LVAR_NEXT(curvar);

7
contrib/ltree/ltree.h
View File

@@ -157,6 +157,8 @@ typedef struct
char data[FLEXIBLE_ARRAY_MEMBER];
} ltxtquery;
typedef bool (*ltree_prefix_eq_func) (const char *, size_t, const char *, size_t);
#define HDRSIZEQT MAXALIGN(VARHDRSZ + sizeof(int32))
#define COMPUTESIZE(size,lenofoperand) ( HDRSIZEQT + (size) * sizeof(ITEM) + (lenofoperand) )
#define LTXTQUERY_TOO_BIG(size,lenofoperand) \
@@ -208,9 +210,10 @@ bool ltree_execute(ITEM *curitem, void *checkval,
int ltree_compare(const ltree *a, const ltree *b);
bool inner_isparent(const ltree *c, const ltree *p);
bool compare_subnode(ltree_level *t, char *qn, int len,
int (*cmpptr) (const char *, const char *, size_t), bool anyend);
ltree_prefix_eq_func prefix_eq, bool anyend);
ltree *lca_inner(ltree **a, int len);
int ltree_strncasecmp(const char *a, const char *b, size_t s);
bool ltree_prefix_eq(const char *a, size_t a_sz, const char *b, size_t b_sz);
bool ltree_prefix_eq_ci(const char *a, size_t a_sz, const char *b, size_t b_sz);
/* fmgr macros for ltree objects */
#define DatumGetLtreeP(X) ((ltree *) PG_DETOAST_DATUM(X))

8
contrib/ltree/ltxtquery_op.c
View File

@@ -58,19 +58,19 @@ 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);
ltree_prefix_eq_func prefix_eq;
cmpptr = (val->flag & LVAR_INCASE) ? ltree_strncasecmp : strncmp;
prefix_eq = (val->flag & LVAR_INCASE) ? ltree_prefix_eq_ci : ltree_prefix_eq;
while (tlen > 0)
{
if (val->flag & LVAR_SUBLEXEME)
{
if (compare_subnode(level, op, val->length, cmpptr, (val->flag & LVAR_ANYEND)))
if (compare_subnode(level, op, val->length, prefix_eq, (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)
(*prefix_eq) (op, val->length, level->name, level->len))
return true;
tlen--;