ldb_mdb: Store pid to change destructor on fork

Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

lib/ldb/ldb_mdb/ldb_mdb.c

@@ -595,6 +595,25 @@ static int lmdb_pvt_destructor(struct lmdb_private *lmdb)
 {
 	struct lmdb_trans *ltx = NULL;
 
+	/* Check if this is a forked child */
+	if (getpid() != lmdb->pid) {
+		int fd = 0;
+		/*
+		 * We cannot call mdb_env_close or commit any transactions,
+		 * otherwise they might appear finished in the parent.
+		 *
+		 */
+
+		if (mdb_env_get_fd(lmdb->env, &fd) == 0) {
+			close(fd);
+		}
+
+		/* Remove the pointer, so that no access should occur */
+		lmdb->env = NULL;
+
+		return 0;
+	}
+
 	/*
 	 * Close the read transaction if it's open
 	 */
@@ -685,6 +704,9 @@ static int lmdb_pvt_open(TALLOC_CTX *mem_ctx,
 		return ldb_mdb_err_map(ret);
 	}
 
+	/* Store the original pid during the LMDB open */
+	lmdb->pid = getpid();
+
 	return LDB_SUCCESS;
 }
 

lib/ldb/ldb_mdb/ldb_mdb.h

@@ -41,6 +41,8 @@ struct lmdb_private {
 	int error;
 	MDB_txn *read_txn;
 
+	pid_t pid;
+
 };
 
 struct lmdb_trans {