Re: [PATCH 3/3] Use g_new() & friends where that makes obvious sense

[Eric Blake]

On Mon, Mar 14, 2022 at 05:01:08PM +0100, Markus Armbruster wrote:
> g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
> for two reasons.  One, it catches multiplication overflowing size_t.
> Two, it returns T * rather than void *, which lets the compiler catch
> more type errors.
> 
> This commit only touches allocations with size arguments of the form
> sizeof(T).
> 
> Patch created mechanically with:
> 
>     $ spatch --in-place --sp-file scripts/coccinelle/use-g_new-etc.cocci \
>            --macro-file scripts/cocci-macro-file.h FILES...
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---

I agree that this is mechanical, but...

<snip>
>  qga/commands-win32.c                     |  8 ++---
>  qga/commands.c                           |  2 +-
>  qom/qom-qmp-cmds.c                       |  2 +-
>  replay/replay-char.c                     |  4 +--
>  replay/replay-events.c                   | 10 +++---
>  scripts/coverity-scan/model.c            |  2 +-

...are we sure we want to touch this particular file?

> diff --git a/scripts/coverity-scan/model.c b/scripts/coverity-scan/model.c
> index 9d4fba53d9..30bea672e1 100644
> --- a/scripts/coverity-scan/model.c
> +++ b/scripts/coverity-scan/model.c
> @@ -356,7 +356,7 @@ int g_poll (GPollFD *fds, unsigned nfds, int timeout)
>  typedef struct _GIOChannel GIOChannel;
>  GIOChannel *g_io_channel_unix_new(int fd)
>  {
> -    GIOChannel *c = g_malloc0(sizeof(GIOChannel));
> +    GIOChannel *c = g_new0(GIOChannel, 1);
>      __coverity_escape__(fd);
>      return c;
>  }

Our model has a definition of g_malloc0(), but I'm not sure whether
Coverity picks up the macro g_new0() in the same manner.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org