Re: [Qemu-devel] [PATCH v2] linux-user: fix to handle variably sized SIOCGSTAMP with new kernels

[Laurent Vivier]

Le 11/07/2019 à 11:24, Daniel P. Berrangé a écrit :
> On Thu, Jul 11, 2019 at 10:02:01AM +0200, Christian Ehrhardt wrote:
>> On Mon, Jun 17, 2019 at 5:35 PM Laurent Vivier <address@hidden> wrote:
>>>
>>> Le 17/06/2019 à 15:11, Daniel P. Berrangé a écrit :
>>>> The SIOCGSTAMP symbol was previously defined in the
>>>> asm-generic/sockios.h header file. QEMU sees that header
>>>> indirectly via sys/socket.h
>>>>
>>>> In linux kernel commit 0768e17073dc527ccd18ed5f96ce85f9985e9115
>>>> the asm-generic/sockios.h header no longer defines SIOCGSTAMP.
>>>> Instead it provides only SIOCGSTAMP_OLD, which only uses a
>>>> 32-bit time_t on 32-bit architectures.
>>>>
>>>> The linux/sockios.h header then defines SIOCGSTAMP using
>>>> either SIOCGSTAMP_OLD or SIOCGSTAMP_NEW as appropriate. If
>>>> SIOCGSTAMP_NEW is used, then the tv_sec field is 64-bit even
>>>> on 32-bit architectures
>>>>
>>>> To cope with this we must now define two separate syscalls,
>>>> with corresponding old and new sizes, as well as including
>>>> the new linux/sockios.h header.
>>>>
>>>> Signed-off-by: Daniel P. Berrangé <address@hidden>
>>>> ---
>>>>  linux-user/ioctls.h        | 15 +++++++++++++++
>>>>  linux-user/syscall.c       |  1 +
>>>>  linux-user/syscall_defs.h  |  5 +++++
>>>>  linux-user/syscall_types.h |  4 ++++
>>>>  4 files changed, 25 insertions(+)
>>>>
>>>> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
>>>> index 5e84dc7c3a..5a6d6def7e 100644
>>>> --- a/linux-user/ioctls.h
>>>> +++ b/linux-user/ioctls.h
>>>> @@ -222,8 +222,23 @@
>>>>    IOCTL(SIOCGIWNAME, IOC_W | IOC_R, MK_PTR(MK_STRUCT(STRUCT_char_ifreq)))
>>>>    IOCTL(SIOCSPGRP, IOC_W, MK_PTR(TYPE_INT)) /* pid_t */
>>>>    IOCTL(SIOCGPGRP, IOC_R, MK_PTR(TYPE_INT)) /* pid_t */
>>>> +
>>>> +#ifdef SIOCGSTAMP_OLD
>>>> +  IOCTL(SIOCGSTAMP_OLD, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timeval)))
>>>> +#else
>>>>    IOCTL(SIOCGSTAMP, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timeval)))
>>>> +#endif
>>>> +#ifdef SIOCGSTAMPNS_OLD
>>>> +  IOCTL(SIOCGSTAMPNS_OLD, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timespec)))
>>>> +#else
>>>>    IOCTL(SIOCGSTAMPNS, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timespec)))
>>>> +#endif
>>>> +#ifdef SIOCGSTAMP_NEW
>>>> +  IOCTL(SIOCGSTAMP_NEW, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timeval64)))
>>>> +#endif
>>>> +#ifdef SIOCGSTAMPNS_NEW
>>>> +  IOCTL(SIOCGSTAMPNS_NEW, IOC_R, MK_PTR(MK_STRUCT(STRUCT_timespec64)))
>>>> +#endif
>>>>
>>>>    IOCTL(RNDGETENTCNT, IOC_R, MK_PTR(TYPE_INT))
>>>>    IOCTL(RNDADDTOENTCNT, IOC_W, MK_PTR(TYPE_INT))
>>>> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
>>>> index b187c1281d..f13e260b02 100644
>>>> --- a/linux-user/syscall.c
>>>> +++ b/linux-user/syscall.c
>>>> @@ -37,6 +37,7 @@
>>>>  #include <sched.h>
>>>>  #include <sys/timex.h>
>>>>  #include <sys/socket.h>
>>>> +#include <linux/sockios.h>
>>>>  #include <sys/un.h>
>>>>  #include <sys/uio.h>
>>>>  #include <poll.h>
>>>> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
>>>> index 7f141f699c..7830b600e7 100644
>>>> --- a/linux-user/syscall_defs.h
>>>> +++ b/linux-user/syscall_defs.h
>>>> @@ -750,6 +750,11 @@ struct target_pollfd {
>>>>
>>>>  #define TARGET_SIOCGSTAMP      0x8906          /* Get stamp (timeval) */
>>>>  #define TARGET_SIOCGSTAMPNS    0x8907          /* Get stamp (timespec) */
>>>> +#define TARGET_SIOCGSTAMP_OLD   0x8906          /* Get stamp (timeval) */
>>>> +#define TARGET_SIOCGSTAMPNS_OLD 0x8907          /* Get stamp (timespec) */
>>>> +#define TARGET_SIOCGSTAMP_NEW   TARGET_IOC(TARGET_IOC_READ, 's', 6, 
>>>> sizeof(long long) + sizeof(long)) /* Get stamp (timeval64) */
>>>> +#define TARGET_SIOCGSTAMPNS_NEW TARGET_IOC(TARGET_IOC_READ, 's', 7, 
>>>> sizeof(long long) + sizeof(long)) /* Get stamp (timespec64) */
>>> kernel defines:
>>>
>>> #define SIOCGSTAMP_NEW   _IOR(SOCK_IOC_TYPE, 0x06, long long[2])
>>> #define SIOCGSTAMPNS_NEW _IOR(SOCK_IOC_TYPE, 0x07, long long[2])
>>>
>>> So it should be TARGET_IOR(0x89, 0x6, abi_llong[2])
>>>
>>> Their codes are 0x80108906 and 80108907.
>>
>> Hi,
>> I found the discussion around this topic being almost a month old.
>> And related to this fedora bug [1] was closed by adding [2] which
>> matches [3] that was nacked in the discussion here.
>>
>> Since I found nothing later (neither qemu commits nor further
>> discussions) I wonder if it has fallen through the cracks OR if there
>> was a kernel fix/change to resolve it (if that is the case a pointer
>> to the related kernel change would be nice)?
> 
> I didn't have time to address the feedback to this v2, and since the
> immediate problem for Fedora has a workaround, its been lower priority
> especially since my understanding of linux-iser is limited.
> 
> IOW, If anyone wants to take over my patch proposal here feel free. It
> would obviously be nice to fix for this 4.1 release if practical.

I'm going to try to update your patch.

Thanks,
Laurent