[PATCH] capabilities: use g_autofree in capabilities.c

[Ján Tomko]

On a Monday in 2022, Jiang Jiacheng wrote:
>Use g_autofree in capabilities.c for some pointers still using manual cleanup,
>and remove unnecessary cleanup.
>
>Signed-off-by: Jiang Jiacheng <jiangjiacheng at huawei.com>
>---
> src/conf/capabilities.c | 44 +++++++++++++----------------------------
> 1 file changed, 14 insertions(+), 30 deletions(-)
>
>@@ -1685,7 +1675,7 @@ static int
> virCapabilitiesHostNUMAInitFake(virCapsHostNUMA *caps)
> {
>     virNodeInfo nodeinfo;
>-    virCapsHostNUMACellCPU *cpus;
>+    g_autofree virCapsHostNUMACellCPU *cpus;

All g_auto variable declarations must be initialized, otherwise we might
try to free some uninitialized pointer.

`ninja test` complains:

>>> MALLOC_PERTURB_=46 /usr/bin/make -C /home/jtomko/build/libvirt/build-aux sc_require_attribute_cleanup_initialization
―――――――――――――――――――――――――――――――――――――――――――――――――――― ✀  ――――――――――――――――――――――――――――――――――――――――――――――――――――
stdout:
make: Entering directory '/home/jtomko/build/libvirt/build-aux'
/home/jtomko/work/libvirt/src/conf/capabilities.c:1678:    g_autofree virCapsHostNUMACellCPU *cpus;
make: Leaving directory '/home/jtomko/build/libvirt/build-aux'
stderr:
variable declared with a cleanup macro must be initialized
make: *** [/home/jtomko/work/libvirt/build-aux/syntax-check.mk:851: sc_require_attribute_cleanup_initialization] Error 1


>     int ncpus;
>     int n, s, c, t;
>     int id, cid;
>@@ -1741,7 +1731,6 @@ virCapabilitiesHostNUMAInitFake(virCapsHostNUMA *caps)
>  error:
>     for (; cid >= 0; cid--)
>         virBitmapFree(cpus[cid].siblings);
>-    VIR_FREE(cpus);

Mixing automatic cleanup of `cpus` with manual clearing of its content
looks a bit confusing to me. virCapabilitiesClearHostNUMACellCPUTopology
does not seem to be easily usable with g_auto, since `ncpus` is stored
separately.

Jano

>     return -1;
> }
>