On Tue, 12 Nov 2019 16:16:39 +0100,
Arnd Bergmann wrote:
>
> From: Baolin Wang <baolin.wang@xxxxxxxxxx>
>
> The struct snd_rawmidi_status will use 'timespec' type variables to record
> timestamp, which is not year 2038 safe on 32bits system.
>
> Thus we introduced 'struct snd_rawmidi_status32' and 'struct snd_rawmidi_status64'
> to handle 32bit time_t and 64bit time_t in native mode, which replace
> timespec with s64 type.
>
> In compat mode, we renamed or introduced new structures to handle 32bit/64bit
> time_t in compatible mode. The 'struct snd_rawmidi_status32' and
> snd_rawmidi_ioctl_status32() are used to handle 32bit time_t in compat mode.
> 'struct compat_snd_rawmidi_status64' is used to handle 64bit time_t.
>
> When glibc changes time_t to 64-bit, any recompiled program will issue ioctl
> commands that the kernel does not understand without this patch.
>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> include/uapi/sound/asound.h | 3 +
> sound/core/rawmidi.c | 132 ++++++++++++++++++++++++++++--------
> sound/core/rawmidi_compat.c | 87 ++++++------------------
> 3 files changed, 128 insertions(+), 94 deletions(-)
>
> diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
> index 7b74524f9406..cb830813da5d 100644
> --- a/include/uapi/sound/asound.h
> +++ b/include/uapi/sound/asound.h
> @@ -651,13 +651,16 @@ struct snd_rawmidi_params {
> unsigned char reserved[16]; /* reserved for future use */
> };
>
> +#ifndef __KERNEL__
> struct snd_rawmidi_status {
> int stream;
> + unsigned char pad1[sizeof(time_t) - sizeof(int)];
> struct timespec tstamp; /* Timestamp */
> size_t avail; /* available bytes */
> size_t xruns; /* count of overruns since last status (in bytes) */
> unsigned char reserved[16]; /* reserved for future use */
> };
Can we use union instead of padding? Something like:
struct snd_rawmidi_status {
union {
int stream;
time_t stream_alignment;
};
struct timespec tstamp; /* Timestamp */
....
thanks,
Takashi
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