Commit 63c75dcd authored by malc's avatar malc
Browse files

Avoid calling qemu_mallocz with zero size 

Currently qemu_mallocz calls malloc and handling of zero by malloc is
implementation defined behaviour:
http://www.opengroup.org/onlinepubs/7990989775/xsh/malloc.html

malloc(0) on AIX returns NULL[1] and qcow2 images without snapshots
are thus unusable

[1] Unless special Linux compatibility define is used when compiling

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6359 c046a42c-6fe2-441c-8c8c-71466251a162
parent 4c621805

block-qcow2.c

+10 −2
Original line number Diff line number Diff line
@@ -1809,6 +1809,12 @@ static int qcow_read_snapshots(BlockDriverState *bs) 
    int64_t offset;

    uint32_t extra_data_size;



    if (!s->nb_snapshots) {

        s->snapshots = NULL;

        s->snapshots_size = 0;

        return 0;

    }



    offset = s->snapshots_offset;

    s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));

    if (!s->snapshots)
@@ -2023,8 +2029,10 @@ static int qcow_snapshot_create(BlockDriverState *bs, 
    snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));

    if (!snapshots1)

        goto fail;

    if (s->snapshots) {

        memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));

        qemu_free(s->snapshots);

    }

    s->snapshots = snapshots1;

    s->snapshots[s->nb_snapshots++] = *sn;