Hello Cyril,
On 08/06/2017 09:38 AM, Cyrill Gorcunov wrote:
> KCMP_EPOLL_TFD
> Check whether the file descriptor idx1 of process pid1 present in epoll(7)
> instance described by idx2 of process pid2. The argument idx2 is an
> address of structure where the target file is described.
>
> struct kcmp_epoll_slot {
> __u32 efd;
> __u32 tfd;
> __u64 toff;
> };
>
> where efd is epoll file descriptor from epoll_create(2) call, tfd is a
> target file number, toff is a target file offset counted from zero. Sev‐
> eral different targets may be registered with the same file descriptor
> number and setting specific offset helps to investigate each of them.
Thanks. I've applied this patch. Is there some example program that
demonstrates the use of this feature?
Cheers,
Michael
> Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
> ---
> man2/kcmp.2 | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 48 insertions(+)
>
> Index: man-pages/man2/kcmp.2
> ===================================================================
> --- man-pages.orig/man2/kcmp.2
> +++ man-pages/man2/kcmp.2
> @@ -156,6 +156,44 @@ See the discussion of the
> .BR CLONE_VM
> flag in
> .BR clone (2).
> +.TP
> +.BR KCMP_EPOLL_TFD
> +Check whether the file descriptor
> +.I idx1
> +of the process
> +.I pid1
> +present in
> +.BR epoll (7)
> +instance described by
> +.I idx2
> +of the process
> +.IR pid2 .
> +The argument
> +.I idx2
> +is an address of a structure where the target file is described.
> +.in +4n
> +.nf
> +.sp
> +struct kcmp_epoll_slot {
> + __u32 efd;
> + __u32 tfd;
> + __u64 toff;
> +};
> +.fi
> +.in
> +.sp
> +where
> +.I efd
> +is epoll file descriptor from
> +.BR epoll_create (2)
> +call,
> +.I tfd
> +is a target file number,
> +.I toff
> +is a target file offset counted from zero.
> +Several different targets may be registered with
> +the same file descriptor number and setting specific
> +offset helps to investigate each of them.
> .PP
> Note the
> .BR kcmp ()
> @@ -246,6 +284,16 @@ Process
> or
> .I pid2
> does not exist.
> +.TP
> +.B EFAULT
> +The epoll slot addressed by
> +.I idx2
> +is outside of the user's address space.
> +.TP
> +.B ENOENT
> +The target file is not present in
> +.BR epoll ()
> +instance.
> .SH VERSIONS
> The
> .BR kcmp ()
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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