LinuxLists.cc - [PATCH 0/3] ptrace.2: explain new commands to work with signals

2013-07-16 08:22:16

Subject: [PATCH 0/3] ptrace.2: explain new commands to work with signals

Andrey Vagin (3):
ptrace.2: place GETSIGINFO and SETSIGINFO near each other
ptrace.2: add description for PTRACE_PEEKSIGINFO
ptrace.2: add description for PTRACE_{GET,SET}SIGMASK

man2/ptrace.2 | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 66 insertions(+), 12 deletions(-)

--
1.8.3.1

2013-07-16 08:22:45

by Andrei Vagin

[permalink] [raw]

Subject: [PATCH 2/3] ptrace.2: add description for PTRACE_PEEKSIGINFO

Retrieve signals without removing them from a queue.

Signed-off-by: Andrey Vagin <[email protected]>
---
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 .
--
1.8.3.1

2013-07-16 08:22:52

by Andrei Vagin

[permalink] [raw]

Subject: [PATCH 3/3] ptrace.2: add description for PTRACE_{GET,SET}SIGMASK

These two commands allow to examine and change mask of blocked signals.

Signed-off-by: Andrey Vagin <[email protected]>
---
man2/ptrace.2 | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/man2/ptrace.2 b/man2/ptrace.2
index e74535e..08697ff 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -356,6 +356,21 @@ If this flag is not set, signals are read from a per-thread queue.
.in
.PP
.TP
+.BR PTRACE_GETSIGMASK " (since Linux 3.11)"
+.\" commit 29000caecbe87b6b66f144f72111f0d02fbbf0c1
+Retrieve mask of blocked signals to the address
+.I data.
+The
+.I addr
+argument contains the size of mask.
+.TP
+.BR PTRACE_SETSIGMASK " (since Linux 3.11)"
+Change mask of blocked signals from the address
+.I data.
+The
+.I addr
+argument contains the size of mask.
+.TP
.BR PTRACE_SETOPTIONS " (since Linux 2.4.6; see BUGS for caveats)"
Set ptrace options from
.IR data .
--
1.8.3.1

2013-07-16 08:22:50

by Andrei Vagin

[permalink] [raw]

Subject: [PATCH 1/3] ptrace.2: place GETSIGINFO and SETSIGINFO near each other

Signed-off-by: Andrey Vagin <[email protected]>
---
man2/ptrace.2 | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/man2/ptrace.2 b/man2/ptrace.2
index 0d77e3f..5fcac2b 100644
--- a/man2/ptrace.2
+++ b/man2/ptrace.2
@@ -255,18 +255,6 @@ On return, the kernel modifies
.B iov.len
to indicate the actual number of bytes returned.
.TP
-.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
-Retrieve information about the signal that caused the stop.
-Copy a
-.I siginfo_t
-structure (see
-.BR sigaction (2))
-from the tracee to the address
-.I data
-in the tracer.
-.RI ( addr
-is ignored.)
-.TP
.BR PTRACE_SETREGS ", " PTRACE_SETFPREGS
Modify the tracee's general-purpose or floating-point registers,
respectively, from the address
@@ -301,6 +289,18 @@ and
is analogous to
.BR PTRACE_GETREGSET .
.TP
+.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
+Retrieve information about the signal that caused the stop.
+Copy a
+.I siginfo_t
+structure (see
+.BR sigaction (2))
+from the tracee to the address
+.I data
+in the tracer.
+.RI ( addr
+is ignored.)
+.TP
.BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
Set signal information:
copy a
--
1.8.3.1

2013-07-18 19:00:40

by Michael Kerrisk (man-pages)

[permalink] [raw]

Subject: Re: [PATCH 1/3] ptrace.2: place GETSIGINFO and SETSIGINFO near each other

Thanks Andrey. Applied.

M

On 07/16/13 10:19, Andrey Vagin wrote:
> Signed-off-by: Andrey Vagin <[email protected]>
> ---
> man2/ptrace.2 | 24 ++++++++++++------------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/man2/ptrace.2 b/man2/ptrace.2
> index 0d77e3f..5fcac2b 100644
> --- a/man2/ptrace.2
> +++ b/man2/ptrace.2
> @@ -255,18 +255,6 @@ On return, the kernel modifies
> .B iov.len
> to indicate the actual number of bytes returned.
> .TP
> -.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
> -Retrieve information about the signal that caused the stop.
> -Copy a
> -.I siginfo_t
> -structure (see
> -.BR sigaction (2))
> -from the tracee to the address
> -.I data
> -in the tracer.
> -.RI ( addr
> -is ignored.)
> -.TP
> .BR PTRACE_SETREGS ", " PTRACE_SETFPREGS
> Modify the tracee's general-purpose or floating-point registers,
> respectively, from the address
> @@ -301,6 +289,18 @@ and
> is analogous to
> .BR PTRACE_GETREGSET .
> .TP
> +.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
> +Retrieve information about the signal that caused the stop.
> +Copy a
> +.I siginfo_t
> +structure (see
> +.BR sigaction (2))
> +from the tracee to the address
> +.I data
> +in the tracer.
> +.RI ( addr
> +is ignored.)
> +.TP
> .BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
> Set signal information:
> copy a
>

2013-08-08 14:46:45

by Andrew Vagin

[permalink] [raw]

Subject: Re: [PATCH 1/3] ptrace.2: place GETSIGINFO and SETSIGINFO near each other

Hi Michael,

On Thu, Jul 18, 2013 at 03:13:39AM +0200, Michael Kerrisk wrote:
> Thanks Andrey. Applied.

You committed one of three patches. What do you think about other
patches?

ptrace.2: add description for PTRACE_PEEKSIGINFO
ptrace.2: add description for PTRACE_{GET,SET}SIGMASK

Thanks,
Andrey

>
> M
>
>
> On 07/16/13 10:19, Andrey Vagin wrote:
> > Signed-off-by: Andrey Vagin <[email protected]>
> > ---
> > man2/ptrace.2 | 24 ++++++++++++------------
> > 1 file changed, 12 insertions(+), 12 deletions(-)
> >
> > diff --git a/man2/ptrace.2 b/man2/ptrace.2
> > index 0d77e3f..5fcac2b 100644
> > --- a/man2/ptrace.2
> > +++ b/man2/ptrace.2
> > @@ -255,18 +255,6 @@ On return, the kernel modifies
> > .B iov.len
> > to indicate the actual number of bytes returned.
> > .TP
> > -.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
> > -Retrieve information about the signal that caused the stop.
> > -Copy a
> > -.I siginfo_t
> > -structure (see
> > -.BR sigaction (2))
> > -from the tracee to the address
> > -.I data
> > -in the tracer.
> > -.RI ( addr
> > -is ignored.)
> > -.TP
> > .BR PTRACE_SETREGS ", " PTRACE_SETFPREGS
> > Modify the tracee's general-purpose or floating-point registers,
> > respectively, from the address
> > @@ -301,6 +289,18 @@ and
> > is analogous to
> > .BR PTRACE_GETREGSET .
> > .TP
> > +.BR PTRACE_GETSIGINFO " (since Linux 2.3.99-pre6)"
> > +Retrieve information about the signal that caused the stop.
> > +Copy a
> > +.I siginfo_t
> > +structure (see
> > +.BR sigaction (2))
> > +from the tracee to the address
> > +.I data
> > +in the tracer.
> > +.RI ( addr
> > +is ignored.)
> > +.TP
> > .BR PTRACE_SETSIGINFO " (since Linux 2.3.99-pre6)"
> > Set signal information:
> > copy a
> >
>

2014-01-20 10:28:10

by Michael Kerrisk (man-pages)

[permalink] [raw]

Subject: Re: [PATCH 2/3] ptrace.2: add description for PTRACE_PEEKSIGINFO

Andrey,

On 07/16/2013 10:19 AM, Andrey Vagin wrote:
> Retrieve signals without removing them from a queue.
>
> Signed-off-by: Andrey Vagin <[email protected]>
> ---
> 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/

2014-01-20 10:28:17

by Michael Kerrisk (man-pages)

[permalink] [raw]

Subject: Re: [PATCH 3/3] ptrace.2: add description for PTRACE_{GET,SET}SIGMASK

On 07/16/2013 10:19 AM, Andrey Vagin wrote:
> These two commands allow to examine and change mask of blocked signals.

Thanks, Andrey.

Applied.

Cheers,

Michael

> Signed-off-by: Andrey Vagin <[email protected]>
> ---
> man2/ptrace.2 | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/man2/ptrace.2 b/man2/ptrace.2
> index e74535e..08697ff 100644
> --- a/man2/ptrace.2
> +++ b/man2/ptrace.2
> @@ -356,6 +356,21 @@ If this flag is not set, signals are read from a per-thread queue.
> .in
> .PP
> .TP
> +.BR PTRACE_GETSIGMASK " (since Linux 3.11)"
> +.\" commit 29000caecbe87b6b66f144f72111f0d02fbbf0c1
> +Retrieve mask of blocked signals to the address
> +.I data.
> +The
> +.I addr
> +argument contains the size of mask.
> +.TP
> +.BR PTRACE_SETSIGMASK " (since Linux 3.11)"
> +Change mask of blocked signals from the address
> +.I data.
> +The
> +.I addr
> +argument contains the size of mask.
> +.TP
> .BR PTRACE_SETOPTIONS " (since Linux 2.4.6; see BUGS for caveats)"
> Set ptrace options from
> .IR data .
>

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/