Full_Name: Juerg Bircher
Version: LMDB master
OS: macOS / linux
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (84.75.150.99)
I had the situation that my custom compare function was called with a MDB_val
with zero size.
I assume this should never happen as a key with zero length should not be
valid?
Unfortunately I do not have a simple case to reproduce it as it happens in large
transaction with a lot of mdb_cursor_put() interleaved with mdb_cursor_get()
calls.
However it is reproducible.
In mdb_cursor_set() at line mdb.c:6943 nodekey.mv_size is zero.
rc = mc->mc_dbx->md_cmp(key, &nodekey);
So the custom compare function is called with a value of zero length.
A possible fix could be to surrond the code from line 6943 to 7007 with a check
if (nodekey.mv_size > 0) {
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
line 6943 to 7007
}
I thank you in advance to inform me:
a. if this fix is correct
b. my assumption is wrong
c. it needs another fix somewhere else
