[CRIU] Re: [PATCH] sockets: Fix file-bound socket check for dgram sockets

[Pavel Emelyanov]

On 02/08/2012 03:24 PM, Pavel Emelyanov wrote:
> On 02/08/2012 03:09 PM, Pavel Emelyanov wrote:
>> On 02/08/2012 03:07 PM, Pavel Emelyanov wrote:
>>> On 02/08/2012 03:03 PM, Cyrill Gorcunov wrote:
>>>> On Wed, Feb 08, 2012 at 02:52:19PM +0400, Cyrill Gorcunov wrote:
>>>>> DGRAM sockets do not care about mount point of
>>>>> file-bound sockets and at time of connect() kernel
>>>>> do not update this information once socket is cretaed,
>>>>> thus do not eliminate dumping of suck sockets name
>>>>> if at least inode match.
>>>>>
>>>>
>>>> Sorry for such silly changelog. In short -- when connect is
>>>> called on stream socket, the kernel updates dentry of sockets
>>>> so that both ino and st_dev match, but in case of dgrams, they
>>>> are not updated and then we will not dump socket name and at
>>>> restore time there will be no way to resolve a name of a socket
>>>> to call connect on (ie sockets00 test-case fails)
>>>
>>> Это неверный патч. Надо так:
>>>
>>> if (sk->type == SOCK_STREAM && (ino != vfs_ino || dev != vfs_dev)
>>> 	/* drop bound name */
>>
>> Нет, стоп, все назад. Ты не прав, Кирил. По ядру пути connect-а
>> не отличаются -- там делается тупой path_walk.
>>
>>>> 	Cyrill
>>>>
>>>
> 
> Надо примерно так, но после этого тест повисает где-то на синхронизации кто отресторился а кто нет :(

А, не, вру. Все ОК, просто у меня ядро без поддержки exe линка. Что, кстати, тоже херово -- линк
не отресторился, а все висит.

> diff --git a/include/util.h b/include/util.h
> index e9c1832..5fab3f4 100644
> --- a/include/util.h
> +++ b/include/util.h
> @@ -264,4 +264,25 @@ FILE *fopen_proc(int pid_dir_fd, char *fmt, ...);
>  #define pr_img_head(type, ...) pr_info("\n"#type __VA_ARGS__ "\n----------------\n")
>  #define pr_img_tail(type)      pr_info("----------------\n")
>  
> +#define KDEV_MINORBITS 20
> +#define KDEV_MINORMASK ((1UL << KDEV_MINORBITS) - 1)
> +
> +static inline u32 kdev_major(u32 kdev)
> +{
> +       return kdev >> KDEV_MINORBITS;
> +}
> +
> +static inline u32 kdev_minor(u32 kdev)
> +{
> +       return kdev & KDEV_MINORMASK;
> +}
> +
> +static inline dev_t kdev_to_odev(u32 kdev)
> +{
> +       /*
> +        * New kernels envcode devices in a new form
> +        */
> +       return (kdev_major(kdev) << 8) | kdev_minor(kdev);
> +}
> +
>  #endif /* UTIL_H_ */
> diff --git a/sockets.c b/sockets.c
> index 2b8a1b4..2c21e5e 100644
> --- a/sockets.c
> +++ b/sockets.c
> @@ -466,7 +466,10 @@ static int unix_collect_one(struct unix_diag_msg *m, struct rtattr **tb)
>                         }
>  
>                         if ((st.st_ino != uv->udiag_vfs_ino) ||
> -                           (st.st_dev != uv->udiag_vfs_dev)) {
> +                           (st.st_dev != kdev_to_odev(uv->udiag_vfs_dev))) {
> +                               pr_info("unix: Dropping path for unlinked bound sk %x.%x real %x.%x\n",
> +                                               (int)st.st_dev, (int)st.st_ino,
> +                                               (int)uv->udiag_vfs_dev, (int)uv->udiag_vfs_ino);
>                                 /*
>                                  * When a listen socket is bound to
>                                  * unlinked file, we just drop his name,