Allow mdb_cursor_close() after readonly txn ends.

Catch mdb_cursor_renew(write txn's cursor).  Add flag C_UNTRACK, so
mdb_cursor_close need not peek inside a possibly-freed readonly txn.
vmware
Hallvard Furuseth 12 years ago
parent 17ffe9c992
commit 385889b0be
  1. 6
      libraries/liblmdb/mdb.c

@ -900,6 +900,7 @@ struct MDB_cursor {
#define C_SHADOW 0x08 /**< Cursor is a dup from a parent txn */ #define C_SHADOW 0x08 /**< Cursor is a dup from a parent txn */
#define C_ALLOCD 0x10 /**< Cursor was malloc'd */ #define C_ALLOCD 0x10 /**< Cursor was malloc'd */
#define C_SPLITTING 0x20 /**< Cursor is in page_split */ #define C_SPLITTING 0x20 /**< Cursor is in page_split */
#define C_UNTRACK 0x40 /**< Un-track cursor when closing */
/** @} */ /** @} */
unsigned int mc_flags; /**< @ref mdb_cursor */ unsigned int mc_flags; /**< @ref mdb_cursor */
MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */ MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
@ -5858,6 +5859,7 @@ mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
if (txn->mt_cursors) { if (txn->mt_cursors) {
mc->mc_next = txn->mt_cursors[dbi]; mc->mc_next = txn->mt_cursors[dbi];
txn->mt_cursors[dbi] = mc; txn->mt_cursors[dbi] = mc;
mc->mc_flags |= C_UNTRACK;
} }
mc->mc_flags |= C_ALLOCD; mc->mc_flags |= C_ALLOCD;
} else { } else {
@ -5877,7 +5879,7 @@ mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs) if (txn == NULL || mc == NULL || mc->mc_dbi >= txn->mt_numdbs)
return EINVAL; return EINVAL;
if (txn->mt_cursors) if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
return EINVAL; return EINVAL;
flags = mc->mc_flags; flags = mc->mc_flags;
@ -5917,7 +5919,7 @@ mdb_cursor_close(MDB_cursor *mc)
{ {
if (mc != NULL) { if (mc != NULL) {
/* remove from txn, if tracked */ /* remove from txn, if tracked */
if (mc->mc_txn->mt_cursors) { if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi]; MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
while (*prev && *prev != mc) prev = &(*prev)->mc_next; while (*prev && *prev != mc) prev = &(*prev)->mc_next;
if (*prev == mc) if (*prev == mc)

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