Andrey,
On 07/16/2013 10:19 AM, Andrey Vagin wrote:
> Retrieve signals without removing them from a queue.
>
> Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
> ---
> man2/ptrace.2 | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/man2/ptrace.2 b/man2/ptrace.2
> index 5fcac2b..e74535e 100644
> --- a/man2/ptrace.2
> +++ b/man2/ptrace.2
> @@ -317,6 +317,45 @@ itself.
> .RI ( addr
> is ignored.)
> .TP
> +.BR PTRACE_PEEKSIGINFO " (since Linux 3.10)"
> +.\" commit 84c751bd4aebbaae995fe32279d3dba48327bad4
> +Retrieve
> +.I siginfo_t
> +structures without removing signals from a queue.
> +.I addr
> +points to a
> +.I ptrace_peeksiginfo_args
> +structure.
> +.I siginfo_t
> +structures are copied into the buffer starting at
> +.I data.
> +The return value contains a number of copied signals (zero indicates
> +that a signal with this sequence number doesn't exist).
> +A result
> +.I siginfo
> +contains a kernel part of
> +.IR si_code
> +(
> +.BR __SI_CHLD,
> +.BR __SI_FAULT,
> +etc), which is not shown in other places.
> +.PP
> +.in +10n
> +.nf
> +struct ptrace_peeksiginfo_args {
> + u64 off; /* from which siginfo to start */
> + u32 flags;
> + s32 nr; /* how may siginfos to take */
> +};
> +.fi
> +
> +Currently here is only one flag
> +.BR PTRACE_PEEKSIGINFO_SHARED
> +for dumping signals from process-wide queue.
> +If this flag is not set, signals are read from a per-thread queue.
> +.in
> +.PP
> +.TP
> .BR PTRACE_SETOPTIONS " (since Linux 2.4.6; see BUGS for caveats)"
> Set ptrace options from
> .IR data .
Long after the fact, I've applied this patch. I reworked the text
somewhat as well. Could you please check that the following is correct:
PTRACE_PEEKSIGINFO (since Linux 3.10)
Retrieve siginfo_t structures without removing signals
from a queue. addr points to a ptrace_peeksiginfo_args
structure that specifies the ordinal position from which
copying of signals should start, and the number of sig‐
nals to copy. siginfo_t structures are copied into the
buffer pointed to by data. The return value contains
the number of copied signals (zero indicates that there
is no signal corresponding to the specified ordinal
position). Within the returned siginfo structures, the
si_code field includes information (__SI_CHLD,
__SI_FAULT, etc.), that are not otherwise exposed to
user space.
struct ptrace_peeksiginfo_args {
u64 off; /* Ordinal position in queue at which
to start copying signals */
u32 flags; /* PTRACE_PEEKSIGINFO_SHARED or 0 */
s32 nr; /* Number of signals to copy */
};
Currently, there is only one flag, PTRACE_PEEKSIG‐
INFO_SHARED, for dumping signals from the process-
wide signal queue. If this flag is not set, signals
are read from the per-thread queue of the specified
thread.
Thanks for the patch!
Michael
--
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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