tdb: Do not allow to pass NULL as the buffer to transaction_write()

This fixes a GCC warning.

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Thu Aug 10 02:26:09 CEST 2017 on sn-devel-144

diff --git a/lib/tdb/common/transaction.c b/lib/tdb/common/transaction.c
index c570cee48da980ae0adccaf83e6c0e884dd8a99b..8ec00256924735c7a255bb3baffcada2afe682dd 100644 (file)
--- a/lib/tdb/common/transaction.c
+++ b/lib/tdb/common/transaction.c
@@ -210,6 +210,10 @@ static int transaction_write(struct tdb_context *tdb, tdb_off_t off,
 {
        uint32_t blk;
 
+       if (buf == NULL) {
+               return -1;
+       }
+
        /* Only a commit is allowed on a prepared transaction */
        if (tdb->transaction->prepared) {
                tdb->ecode = TDB_ERR_EINVAL;
@@ -234,9 +238,7 @@ static int transaction_write(struct tdb_context *tdb, tdb_off_t off,
                }
                len -= len2;
                off += len2;
-               if (buf != NULL) {
-                       buf = (const void *)(len2 + (const char *)buf);
-               }
+               buf = (const void *)(len2 + (const char *)buf);
        }
 
        if (len == 0) {
@@ -289,11 +291,7 @@ static int transaction_write(struct tdb_context *tdb, tdb_off_t off,
        }
 
        /* overwrite part of an existing block */
-       if (buf == NULL) {
-               memset(tdb->transaction->blocks[blk] + off, 0, len);
-       } else {
-               memcpy(tdb->transaction->blocks[blk] + off, buf, len);
-       }
+       memcpy(tdb->transaction->blocks[blk] + off, buf, len);
        if (blk == tdb->transaction->num_blocks-1) {
                if (len + off > tdb->transaction->last_block_size) {
                        tdb->transaction->last_block_size = len + off;