Re: [Qemu-devel] [PATCH v2] linux-user: add name_to_handle_at/open_by_handle_at

[Peter Maydell <peter.maydell@linaro.org>]

On 1 September 2015 at 21:27, Laurent Vivier <laurent@vivier.eu> wrote:
> This patch allows to run example given by open_by_handle_at(2):
>
>       The following shell session demonstrates the use of these two programs:
>
>            $ echo 'Can you please think about it?' > cecilia.txt
>            $ ./t_name_to_handle_at cecilia.txt > fh
>            $ ./t_open_by_handle_at < fh
>            open_by_handle_at: Operation not permitted
>            $ sudo ./t_open_by_handle_at < fh      # Need CAP_SYS_ADMIN
>            Read 31 bytes
>            $ rm cecilia.txt
>
>        Now  we delete and (quickly) re-create the file so that it has the same
>        content and (by chance) the  same  inode.[...]
>
>            $ stat --printf="%i\n" cecilia.txt     # Display inode number
>            4072121
>            $ rm cecilia.txt
>            $ echo 'Can you please think about it?' > cecilia.txt
>            $ stat --printf="%i\n" cecilia.txt     # Check inode number
>            4072121
>            $ sudo ./t_open_by_handle_at < fh
>            open_by_handle_at: Stale NFS file handle
>
> See the man page for source code.
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
> v2: Rename function parameters, swap fh->handle_type in both functions,
>     When I have re-tested the patch I have found a bug in the size of
>     the data, so I fix this too (handle_bytes is the size of f_handle[]
>     only, not of the whole structure)

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

(I guess the signalfd patch needs to be rebased on top of this,
since this adds another syscall that returns an fd...)

thanks
-- PMM