gwj / at91sam9263 · Commits

Commit 63c75dcd669d011f438421980b4379827da4bb1c

Authored by malc
1 parent 4c621805

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
Inline Side-by-side
Showing 1 changed file with 10 additions and 2 deletions
block-qcow2.c
  View file @63c75dc
@@ -1809,6 +1809,12 @@ static int qcow_read_snapshots(BlockDriverState *bs) @@ -1809,6 +1809,12 @@ static int qcow_read_snapshots(BlockDriverState *bs)
1809 int64_t offset; 1809 int64_t offset;
1810 uint32_t extra_data_size; 1810 uint32_t extra_data_size;
1811 1811
  1812 + if (!s->nb_snapshots) {
  1813 + s->snapshots = NULL;
  1814 + s->snapshots_size = 0;
  1815 + return 0;
  1816 + }
  1817 +
1812 offset = s->snapshots_offset; 1818 offset = s->snapshots_offset;
1813 s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot)); 1819 s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
1814 if (!s->snapshots) 1820 if (!s->snapshots)
@@ -2023,8 +2029,10 @@ static int qcow_snapshot_create(BlockDriverState *bs, @@ -2023,8 +2029,10 @@ static int qcow_snapshot_create(BlockDriverState *bs,
2023 snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot)); 2029 snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
2024 if (!snapshots1) 2030 if (!snapshots1)
2025 goto fail; 2031 goto fail;
2026 - memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));  
2027 - qemu_free(s->snapshots); 2032 + if (s->snapshots) {
  2033 + memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
  2034 + qemu_free(s->snapshots);
  2035 + }
2028 s->snapshots = snapshots1; 2036 s->snapshots = snapshots1;
2029 s->snapshots[s->nb_snapshots++] = *sn; 2037 s->snapshots[s->nb_snapshots++] = *sn;
2030 2038