Re: [PATCH 1/2] util/uuid: Add UUID_STR_LEN definition

[Philippe Mathieu-Daudé]

On 25/10/23 12:12, Cédric Le Goater wrote:
> qemu_uuid_unparse() includes a trailing NUL when writing the uuid
> string and the buffer size should be UUID_FMT_LEN + 1 bytes. Add a
> define for this size and use it where required.
>
> Cc: Fam Zheng <fam@euphon.net>
> Signed-off-by: Cédric Le Goater <clg@redhat.com>
> ---
>   include/qemu/uuid.h              | 1 +
>   block/parallels-ext.c            | 2 +-
>   block/vdi.c                      | 2 +-
>   hw/core/qdev-properties-system.c | 2 +-
>   hw/hyperv/vmbus.c                | 4 ++--
>   migration/savevm.c               | 4 ++--
>   tests/unit/test-uuid.c           | 2 +-
>   util/uuid.c                      | 2 +-
>   8 files changed, 10 insertions(+), 9 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> diff --git a/include/qemu/uuid.h b/include/qemu/uuid.h
> index 
> e24a1099e45f2dfc330a578d3ccbe74f3e52e6c1..4e7afaf1d5bd5d382fefbd6f6275d69cf25e7483
>  100644
> --- a/include/qemu/uuid.h
> +++ b/include/qemu/uuid.h
> @@ -79,6 +79,7 @@ typedef struct {
>                    "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
>   
>   #define UUID_FMT_LEN 36
> +#define UUID_STR_LEN (UUID_FMT_LEN + 1)
>   
>   #define UUID_NONE "00000000-0000-0000-0000-000000000000"

After this patch, when do we need UUID_FMT_LEN?
If it is dangerous, better drop it and keep:

#define UUID_STR_LEN (36 + 1)

or

#define UUID_STR_LEN (36 + sizeof('\0'))